Top 20 HDI PCB Manufacturers in the World

HDI PCB manufacturers are companies that create high-density interconnect circuit boards using incorporated microvias and fine conductors to increase wiring density. Research their documented capabilities in terms of stack-up, via map, materials, test requirements and production requirements. There are 20 listed suppliers and a method for shortlisting them.

Note: Except for PCBark, which appears first by editorial request, the remaining companies are presented in no particular order. First placement doesn’t represent an independently verified ranking by global market share, technical capability or product quality. HDI PCB supplier selection should be based on stack-up, microvia structure, layer count, trace/space, impedance requirements, laminate, copper weight, reliability class, testing requirements, production quantity and lead time.

The sources were reviewed on September 8, 2026. An official page often establishes what a supplier publishes. It doesn’t independently verify a supplier’s production performance. If a founding date, headquarters or a process limit wasn’t documented, that was noted. This is a sourcing guide for purchasing. Choosing the right HDI PCB supplier starts with defining the HDI PCB manufacturing capabilities required by the actual board, rather than comparing unrelated minimum dimensions. Those working in regulated or defense procurement will need additional verification of sourcing, manufacturing and qualification of the programs.

HDI Supplier Evidence Matrix: 20 Manufacturers at a Glance

The HDI Supplier Evidence Matrix will help you identify a manufacturing path. The last column is the first fact required to be provided. A supplier with fewer public numbers may be appropriate, while a minimum feature may apply to specific materials or a sample process.

The following profiles cover bare-board fabrication. Several companies also offer pcb assembly, layout or semiconductor substrates. Those additional services are noted where applicable, but an assembly service or substrate specification isn’t used as evidence of HDI bare-board capability.

A PCB service request should identify the product before addressing the size of the supplier. A rigid PCB, a rigid-flex HDI circuit board and a package substrate are distinct offerings. Published PCB capabilities help identify candidates; an approved process document defines which PCB manufacturing capabilities will apply to the given order.

1. PCBark

Company and history: PCBark’s corporate pages identify Shenzhen Linghangda Technology Co., Ltd. and say 2010 is the start date. The stated headquarters is Shenzhen, Guangdong, China; the published history also tells of manufacturing growth in Huizhou and Jiangxi.

Introduction and business type: PCBark offers custom PCB fabrication and related assembly services. Its HDI PCB fabrication service is the relevant starting point for a board-level enquiry. Assembly scope should be quoted separately.

HDI products and structures: The capability table separates standard 1+N+1 and 2+N+2 builds from advanced 3+N+3 and any-layer builds. Published via structures include filled and capped vias.

Materials and finishes: Standard material options include FR-4 and high-Tg FR-4, with advanced Rogers, polyimide and mixed-material options. Specify the exact grade and surface finish in the request; a material family name isn’t approval for every stack-up.

Published limits: Standard values include 3/3 mil trace/space and 0.10 mm laser drilling; advanced values include 2/2 mil and 0.075 mm. These are separate process classes, subject to engineering review.

Applications, standards and testing: The service applies to compact and controlled-impedance electronic designs and boards. Published inspection options include automated optical inspection, electrical testing, microsections and thermal checks. IPC-6012 Class 2 or Class 3 build specifications must be agreed upon for the order.

Strength and purchasing caution: The explicit standard/advanced split makes an initial enquiry easier to structure. Request the producing site, current certificate scope, material availability, minimum order and delivery commitment with the approved drawing.

Official website: https://pcbark.com/

2. AT&S

Company, founding and headquarters: AT&S was founded in 1987 and is located in Leoben, Austria. It’s an international advanced interconnect products manufacturer.

Introduction and business type: The company manufactures printed circuit boards and other interconnection products for demanding electronics programs. The HDI offering should be assessed through the proposed business unit and plant, rather than through group scale, alone.

HDI products and structures: AT&S defines laser microvias, sequential build-up layers and any-layer interconnection, as technologies for advanced constructions. These technologies enable dense connectivity where routing consumes a large footprint of the board.

Materials and finishes: The HDI discussion includes use of halogen free materials. The reviewed product page doesn’t give a laminate-grade or finish matrix. Request a materials list tied to the construction and assembly processes.

Published limits: There’s no current production table that includes laser diameter, trace/space, copper weight, and layer count, and which has been validated in the reviewed HDI page. Don’t use the package-substrate business to determine those values.

Applications, standards and testing: Examples that are published cover automotive electronics, cameras, medical devices, communication systems, and compact consumer products. Request the relevant plant certificates, qualification records, and agreed electrical and reliability tests.

Strength and purchasing caution: There are a few interconnect technologies that make AT&S pertinent to programs where design coordination is critical. Public statements don’t indicate readiness to manufacture a given prototype quantity or schedule. Confirm commercial fit before committing a layout to a proprietary production control rule.

Official website: https://ats.net/

3. TTM Technologies

Company, founding and headquarters: TTM Technologies was formed in 1998. The company information identifies its headquarters as Santa Ana, California, USA.

Introduction and business type: TTM manufactures printed circuit boards and other engineered electronic products. Their HDI products incorporate a suite of microvia processes. The industry terminology surrounding microvia processes is important as is the moniker HDI.

HDI products and structures: Some published pathways include conventional, stacked, deep and deep-stacked microvias. NextGen-SMV features a conductive-paste-to-copper metallurgical bond and a single lamination cycle. This structure shouldn’t be treated as identical to conventional, sequentially laminated, copper-filled stacked microvias.

Materials and finishes: TTM mentions thin, high-performance materials and RF-related fabrication. Obtain the laminate, finish and layer-by-layer material specification for the selected pathway.

Published limits: TTM’s HDI page differentiates a laser-drilled diameter of approximately 100 micrometres from a pad diameter of approximately 200 micrometres. These are different dimensions. Finer substrate-like product claims on the page don’t automatically apply to conventional HDI.

Applications, standards and testing: These include networking, medical monitoring, automotive sensing and aerospace applications. Plant eligibility, construction specific qualification and the scope of the certificates would need to be confirmed separately.

Strength and purchasing caution: The range of via technologies provides different interconnection options. Request the exact fabrication route in writing, including its evidence of qualification. A quick-turn statement for NextGen-SMV isn’t a guarantee for all boards manufactured by TTM that fall under the HDI product line.

Official website: https://www.ttm.com/

4. Unimicron: Germany Manufacturing Route

Company, founding and headquarters: This report discusses Unimicron’s German manufacturing subsidiary in Geldern, Germany. The company has RUWEL heritage dating to 1945. This date shouldn’t be used as the founding date of the broader Unimicron group.

Introduction and business type: The German business produces printed circuit boards and explains access to Asian group facilities. Therefore, the quotation must specify where the requested board will be fabricated.

HDI products and structures: The published portfolio includes HiDensity PCB alongside multilayer and semiflex products. The reviewed overview establishes an HDI offering but doesn’t include stacked, staggered, or any-layer combinations.

Materials and finishes: Request the approved material grade, surface finish, copper specification and regional supply alternatives. These weren’t reviewed as a complete universal matrix in the published overview.

Published limits: The portfolio mentions multilayers of up to 24 layers. This is a general PCB statement and doesn’t confirm that all 24-layer designs are available as HDI with the same definition of geometry.

Applications, standards and testing: Published markets are automotive, industrial and energy electronics. Confirm the certificate holder, site address, applicable product requirements and qualification package for the quoted plant.

Strength and purchasing caution: The German manufacturing subsidiary and group access can support regional sourcing. Site identity is essential. Don’t confuse European sales contact with European fabrication or assume the group’s capability is available at the German site.

Official website: https://www.unimicron-germany.de/

5. Compeq

Company, founding and headquarters: Compeq Manufacturing was created on August 30, 1973. Its headquarters and its operations in Luzhu are in Taoyuan, Taiwan.

Introduction and business type: Compeq has its own facilities for producing printed circuit boards, and for offering surface-mount assembly services. Detailed descriptions of the plants refer to advanced HDI, high-layer-count boards and separate assembly activities.

HDI products and structures: The product catalog includes HDI and high-layer-count flexible and rigid-flex boards. The introduction of HDI covers the use of microvia interconnection in the construction of compact electronic devices.

Materials and finishes: For the laminate and finish, an order-specific list is required. The technology figures in annual reports shouldn’t be considered the current catalog of materials, finishes and copper thicknesses.

Published limits: A complete current HDI limit table wasn’t defined in this review. Therefore, rather than providing the historical data of fine-line or build-up as current capability, this guide omits these data from the description of modern production.

Applications, standards and testing: Compeq describes applications related to smartphones, tablets, and multimedia. Plant information indicates that HDI operations are performed in certain areas, while other facilities are dedicated to assembly operations. Request the fabricator’s latest certification and the inspection plan.

Strength and purchasing caution: The detailed descriptions of the products at each site allow prospective buyers to formulate a more precise sourcing request. It should also be noted whether the request is for bare boards or assembled boards. Having a surface-mount assembly facility doesn’t prove microvia fabrication capability. Minimum quantities and qualification lead times remain commercial questions.

Official website: https://www.compeq.com.tw/

6. Tripod Technology

Company, founding and headquarters: No year of founding and no exact location for the headquarters was found for Tripod Technology in the material covered in this article. Tripod is a Taiwan-based PCB manufacturing company.

Introduction and business type: Manufacturing disclosures for Tripod include the development of HDI technology. Limited publicly available research can provide insight into probable future direction, but should be interpreted with the understanding that manufacturing disclosures and development goals are likely to remain distinct.

HDI products and structures: The annual report under review describes HDI development and discusses technologies focused on process stability and yield, but a specific four-level stacked construction was not verified. This shouldn’t be interpreted as implying that full HDI technology solutions are available on a custom basis for any customer’s production requirements.

Materials and finishes: Require the proposed factory to provide an approved laminate and surface-finish list. No complete materials matrix or universal range of finishes was verified in the research disclosures under review.

Published limits: The annual report discusses production introduction of 40/40 micrometre line/space and development work on 30/30 micrometre line/space. In this guide, we don’t consider these development stages as current production minima.

Applications, standards and testing: Program suitability depends on the family of released products and the specific factory route. Please request the latest version of the design-rule document, the certificates appropriate to this version, as well as evidence of reliability and the inspection.

Strength and purchasing caution: The evidence is important as it provides insight into process development. The procurement requirement is to determine which part of the development has reached qualified production. Ask for the release date of the capability document and confirm that the proposed quantity, material, and via architecture are included.

Official website: https://www.tripod-tech.com/

7. Zhen Ding Technology

Company, founding and headquarters: The corporate history of Zhen Ding Technology Holding distinguishes its incorporation in 2006 from its earlier business activities. The Group has located its headquarters in Taoyuan, Taiwan.

Introduction and business type: Zhen Ding manufactures several families of PCB and interconnection products. At the group level, its HDI page gives a technology overview as opposed to a production-ready specification for one factory.

HDI products and structures: Published information includes blind and buried vias, multiple layer structures and high end any layer development. Confirm the release of the required structure with the relevant production operation.

Materials and finishes: The overview refers to different material combinations, but no current laminate-grade or surface-finish matrix was verified. These should be included in the stack-up submitted with the quote.

Published limits: No universal minimum trace/space, laser diameter or maximum HDI layer count is used in this document. Illustrations of technologies aren’t evidence that all illustrated features can be combined.

Applications, standards and testing: Examples on file include wearables, tablets, solid-state storage, servers, and augmented- and virtual-reality devices. Request the actual plant’s certificate, scope, inspection plan and qualification records.

Strength and purchasing caution: The broad interconnection portfolio is relevant for applications where board density and product miniaturization drive design choices. Buyers must still obtain project-level assurance on materials, capacity and order acceptance. This article doesn’t repeat an unconditional claim that HDI becomes cheaper above a particular layer count; that requires a same-design cost comparison.

Official website: https://www.zdtco.com/

8. Meiko Electronics

Company, founding and headquarters: Meiko Electronics was founded on November 25, 1975 and is based in Ayase, Kanagawa Japan.

Introduction and business type: Meiko manufactures printed circuit boards across several product families. Its MEIKO Labo service provides a clearly described development and prototype route.

HDI products and structures: The reviewed Labo offering uses laser processing and plating for build-up interconnections. The company also lists HDI within its wider PCB portfolio, alongside other constructions.

Materials and finishes: Request the available dielectric grades, finished copper and surface treatment for the particular Labo or production route. The reviewed prototype page doesn’t establish every material combination offered across the group.

Published limits: MEIKO Labo describes 4–10-layer development and prototype boards. This is the scope of that service, not a maximum layer count for all Meiko production and not proof of every 10-layer stacked-via construction.

Applications, standards and testing: Published use cases include automotive electronics, wearables and cameras. Define requirements for prototype inspection early on and ask about how construction qualification will apply to the intended volume production facility.

Strength and purchasing caution: A named development service offers engineers a specific route for early stage hardware. The following question is if the prototype process is adequate for duplicating the production process. Confirm any change to the factory, material, lamination, tooling, or test process before considering a prototype as approval for volume production.

Official website: https://www.meiko-elec.com/

9. Kinwong

Company, founding and headquarters: Kinwong, according to their information, was founded in 1993 and is located in Shenzhen, China.

Introduction and business type: Kinwong is a PCB manufacturer with many different board technologies. Their HDI (high density interconnect) presentation distinguishes patterning routes instead of offering an undifferentiated fine line number.

HDI products and structures: Their published product range includes any-layer HDI and modified semi-additive processing (mSAP). Confirm which process will be used for the proposed layer stack and copper distribution.

Materials and finishes: A complete current grade-by-grade laminate and finish matrix hasn’t been verified by the reviewed HDI page. Material substitution, copper foil, and plating should be specified in the quote.

Published limits: Kinwong states 30/30 micrometre line/space for mSAP and 40/40 micrometre for tenting. These values are process specific. Their inclusion, referencing microvias at or below 0.15 mm, shouldn’t be converted to a minimum laser diameter.

Applications, standards and testing: The interconnection addresses dense electronic circuitry. It’s necessary to confirm end-use suitability, factory certification, and test requirements against the board’s reliability requirements.

Strength and purchasing caution: Process-specific disclosures provide an anchor for technical discussion of line formation and copper thickness. These disclosures don’t allow speculating on minimum spacing, maximum copper weight, and their combination in the most complex any-layer stack. Please ask for one signed capability response covering the full proposed construction and production quantity.

Official website: https://www.kinwong.com/

10. Shennan Circuits

Company, founding and headquarters: Shennan Circuits is a China-based manufacturer. This review didn’t independently confirm the founding year and exact headquarters address from the primary pages used, so those fields remain unverified here.

Introduction and business type: The company manufactures printed circuit boards and other electronic interconnection products. Its published product examples provide more precise evidence than a broad advanced-manufacturing label.

HDI products and structures: One disclosed enterprise solid-state-drive example is a 14-layer rigid-flex board with a four-level HDI structure. That’s a specific product example, not a promise covering every board with the same nominal layer count.

Materials and finishes: The same example identifies high-Tg FR-4 combined with polyimide and an OSP surface finish. Keep those details attached to that example when discussing alternatives.

Published limits: General PCB tables distinguish production and sample capabilities. Their highest layer counts and smallest sample holes must not be repackaged as a single mass-production HDI limit.

Applications, standards and testing: The reviewed evidence directly supports an enterprise-storage application. Ask for the nominated factory’s certificate scope and the electrical, impedance and reliability records required for your construction.

Strength and purchasing caution:A documented product configuration offers a useful starting point for a similar enquiry. Similarity isn’t qualification however. Have the manufacturer identify differences in via sequence, rigid-flex transition, material, thickness and test requirements before relying on the example.

Official website: https://www.scc.com.cn/

11. WUS Printed Circuit, Taiwan

Company, founding and headquarters: The Taiwan WUS printed circuit, whose official Chinese name is 楠梓電子, is what this entry is about. This entry isn’t about the Kunshan company with a similar name. The technology page provides no information regarding the year of founding or the exact location of the headquarters.

Introduction and business type: WUS produces printed circuit boards and also publishes several advanced interconnection technologies. The first step in sourcing is to identify the correct legal entity.

HDI products and structures: The WUS technology page states that the company can produce multi-stage HDI from +1 to +8 and any-layer boards from 4 to 18 layers. The page also states that they can produce stacked and skip vias, plated over filled vias and backdrilling.

Materials and finishes: There are some descriptions of high-speed and low-loss materials. Request specific grades of laminate and surface finishes. The family descriptions wouldn’t define an approved stack-up.

Published limits: The figures regarding stage and layer are published ranges. The reviewed page doesn’t describe all combinations of minimum trace/space, copper weight or finished board thickness.

Applications, standards and testing: The technology portfolio addresses dense, high-speed circuitry and also includes embedded components. The suitability of the program and current site certificates require an order-specific response.

Strength and purchasing caution: The build-up range that’s described helps to identify an advanced-HDI route. Confirm that the quote comes from the intended Taiwan entity and names its producing site. Don’t include another WUS company’s facilities, customers, certifications or production limits in this profile.

Official website: https://www.wus.com.tw/

12. Korea Circuit

Company, founding and headquarters: Korea Circuit’s history starts in 1972. Their published address is in Ansan, Gyeonggi-do, South Korea. The relevant official domain is kcg.co.kr.

Introduction and business type: Korea Circuit makes printed circuit boards and shares info about application-specific capabilities. Their mobile-board page is an excellent case to explain to customers the importance of keeping the limits of each product family together.

HDI products and structures: The mobile offering shows stacked and staggered vias, filling and metal capping. These descriptions provide a basis to discuss dense component fanout.

Materials and finishes: The page lists FR-4, high-Tg, low-dielectric-constant, low-loss and halogen-free material options, as well as resin-coated copper. Published surface finishes include ENIG and OSP.

Published limits: The mobile table has 4–12 layers, 30 micrometre conductor width, 40 micrometre spacing and 80 micrometre laser drilling. Don’t mix these with the higher layer count or the different storage-board geometry.

Applications, standards and testing: The limits described are for mobile electronics. For other applications, please request the current inspection plan, material approval and site-specific qualifications.

Strength and purchasing caution: Product-specific tables can help in providing clarity for the intended board, as long as it falls under that family. However, these need to be confirmed for the complete design. The supplier should provide the applicable table revision along with manufacturing approval, a via map and copper definition.

Official website: https://www.kcg.co.kr/

13. Daeduck Electronics

Company, founding and headquarters: Daeduck’s corporate heritage dates to 1965, while the current legal company followed a 2020 spin-off. Their headquarters is in Ansan, South Korea. The dates serve different milestones.

Introduction and business Type: Daeduck manufactures PCB and semiconductor package products. Current corporate disclosures are critical, as older descriptions for its mobile HDI business don’t keep up with the portfolio as it currently stands.

HDI products and structures: The 2024–2025 disclosures include descriptions of high-end HDI and multilayer boards for use in semiconductor, data-center and network applications. Package substrate capabilities as a separate product line are also included.

Materials and finishes: What are the material grade, copper treatments, and surface finishes for the HDI product family? This review didn’t verify a current list of compatible material, copper-treatment and finish combinations.

Published limits: There’s no validated all-purpose HDI table for minimum line/space, laser diameter or maximum build-up count. Therefore, historical mobile-board figures can’t be used as present production limits.

Applications, standards and testing: The current data provides support for data-center, communication and semiconductor specific board applications. Request from the selected site the relevant certificates and reliability and inspection related requirements.

Strength and purchasing caution: Current high-end board disclosures position Daeduck in those application families. Buyers should first verify product and program fit. A well known company name doesn’t mean a product line described in an older brochure is presently offered under the same process, legal entity or with the same terms.

Official website: https://www.daeduck.com/

14. Unitech, Taiwan

Company, founding and headquarters: Unitech Printed Circuit Board Corp. was established in 1984. Its corporate disclosure identifies Tucheng, New Taipei, Taiwan, as headquarters. This is the Taiwan business at pcbut.com.tw.

Introduction and business type: Unitech makes printed circuit boards, including HDI and rigid-flex products. The identity must be checked carefully as other firms use similar English names.

HDI products and structures: Corporate reporting gives information on HDI circuitry for smart electronic devices. Historical reports discuss laser microvias and via-filling, but these accomplishments aren’t a current release document for every configuration of stacked-via.

Materials and finishes: The reviewed corporate disclosure doesn’t give a complete current laminate and finish matrix. Ask the proposed factory to identify grades that are approved and whether any customer approval is necessary for substitutions.

Published limits: Current universal minimum trace/space, laser diameter and maximum HDI layer specifications weren’t verified. They should be left as blank entries in the inquiry, not populated from suppliers’ databases.

Applications, standards and testing: The published range supports smart-device and compact-electronics applications. Request the appropriate site-specific certificates, inspection reports and the HDI qualification package.

Strength and purchasing caution: The combination of HDI and rigid-flex may be pertinent where dense routing intersects mechanical constraints. Check if the proposed construction relies on a single qualified route or multiple subcontracted steps. Old process development dates indicate previous work performed, not current production capacity or a firm commitment to a minimum order.

Official website: https://www.pcbut.com.tw/

15. Nan Ya PCB

Company, founding and headquarters: Nan Ya Printed Circuit Board Corporation was founded in October 1997. Its official company profile locates Taipei, Taiwan, as the headquarters; manufacturing-site locations should be recorded separately.

Introduction and business type: Nan Ya PCB manufactures bare printed circuit boards and semiconductor package substrates. Those businesses have overlapping interconnection interests, but distinct procurement requirements.

HDI products and structures: The profile contains HDI boards and rigid-flex boards as well as ABF and other package-substrate products. The presence of a fine-feature substrate process doesn’t imply the same minimum feature size for HDI bare boards.

Materials and finishes: Request a board-specific laminate, copper and finish specification. The reviewed company overview doesn’t contain a current matrix of HDI material combinations.

Published limits: This guide won’t adopt a universal laser diameter, trace/space, or any-layer count from old brochures. Request the latest released capability document for the selected board fabrication route.

Applications, standards and testing: The company serves electronic interconnection applications through several product families. Request the factory’s current certificate scope and the electrical, impedance and reliability evidence applicable to your bare board.

Strength and purchasing caution: The distinction between board and substrate businesses is useful when discussing a complex electronics program. It also induces a common type of mistake. Make sure you describe the product category in the query to avoid confusing an impressive package-substrate number for a HDI pcb production limit.

Official website: https://www.nanyapcb.com.tw/

16. Würth Elektronik

Company, founding and headquarters: Würth Elektronik’s circuit-board business describes operations dating to 1971. It’s based in Germany; the exact contracting entity and producing plant should be confirmed with the enquiry.

Introduction and business type: The company’s Circuit Board Technology business produces pcbs. The greater Würth Elektronik group’s component products are entirely separate from this business.

HDI products and structures: Published families include MICROVIA.hdi, SLIM.hdi and ADVANCED.hdi. This page deals with stacked, staggered and buried connections, as well as sequential lamination and advanced interconnections for small modules.

Materials and finishes: You should select the product family before you agree to a material and a finish. Published standard stack-ups aren’t necessarily impedance-matched. The manufacturer provides a separate impedance-design service.

Published limits: The SLIM.hdi discussion includes 50 micrometre structures. Advanced module examples include 0.3 mm BGA applications under specific design conditions. Neither is necessarily a universal laser-hole diameter or a logical assumption for HDI.

Applications, standards and testing: An identifiable application can be seen in the named 2025 modular smartwatch project with OVTech which is conducted by Würth Elektronik and OVTech, not by PCBark. Please request the applicable factory certificates and construction-related tests.

Strength and purchasing caution: Named technology families and stack-up support help to shape an engineering enquiry. Keep the chosen family, impedance requirements and qualification route consistent. Altering a family after the release of the layout may bring a new assumption about the original design approval.

Official website: https://www.we-online.com/

17. Sierra Circuits

Company, founding and headquarters: Sierra Circuits was founded in 1986 and is based in Sunnyvale, California, USA.

Introduction and business type: Sierra offers PCB fabrication and related engineering services. Their HDI page contains detailed production tables, which can assist in determining how a supplier identifies specific features.

HDI products and structures: Published options include stacked and staggered microvias, copper filling and sequential lamination. The table also includes a microvia aspect ratio of 0.75:1 and up to four lamination cycles.

Materials and finishes: Isola 370HR, Ventec VT-47 and polyimide are some of the published materials. Published finishes include ENIG, ENEPIG and OSP. These options are all subject to approval for the complete structure.

Published limits: The same page uses a 2 mil hole headline, a 3 mil smallest-laser-drill table entry and a 4 mil blind-via laser minimum. These figures need scope clarification. Copper-dependent trace/space tables must also remain tied to their specified copper thickness.

Applications, standards and testing: Published options for inspection include electrical testing, time domain reflectometry, microsections and first-article documentation. Agree the qualification and acceptance package required for the intended application.

Strength and purchasing caution: Detailed tables answer useful engineering questions while showing inconsistencies that need to be resolved prior to releasing layout. Ask Sierra to return one approved drilling and copper schedule rather than the lowest from various sections of their website.

Official website: https://www.protoexpress.com/

18. Cirexx International

Company, founding and headquarters: Cirexx International established their business in 1980 and claims Silicon Valley, California, USA, as their location. The business address must be verified on the quote.

Introduction and Business Type: According to its website, Cirexx provides PCB layout, in-house fabrication and assembly. Its HDI webpage notes that standard fabrication processing is done internally.

HDI products and structures: The published process list comprises laser drilling, blind and buried vias, sequential lamination, via-in-pad, backdrilling and controlled-depth drilling.

Materials and finishes: Request the available laminate and surface-finish options for HDI construction. A broad fabrication portfolio doesn’t guarantee that each of the materials offered elsewhere can be processed by the same microvia technology.

Published Limits: The page mentions 0.3 mm fine-pitch applications and controlled impedance to ±10%. Component pitch isn’t drill diameter. The evidence reviewed doesn’t provide a universal minimum size of a laser-drilled hole.

Applications, Standards and Testing: Cirexx specifies medical, aerospace, military, and other difficult applications of electronics. Their published quality and registration labels require verification of the current holder, site and scope and don’t approve all orders.

Strength and Purchasing Caution: Integrated layout and fabrication support can help resolve design concerns before release. Keep in mind the HDI-specific lead time. A 5–15-day HDI statement and a generic quick-turn statement elsewhere aren’t comparable. The quote should name the approved files, start condition, inspection scope and delivery date.

Official website: https://www.cirexx.com/

19. PCBWay

Company, founding and headquarters: PCBWay is a China-based PCB fabrication service. An exact founding year and headquarters were not confirmed from the primary pages used in this review.

Introduction and business type: PCBWay provides custom fabrication and assembly services for PCBs. The page dedicated to HDI has evaluation notes that help explain/interpret the headline capability numbers.

HDI Products and structures: The published build-up options have multiple levels of HDI. More complex builds require an engineering evaluation and can’t be automatically accepted through the order form.

Materials and finishes: The laser-drilling notes connect some advanced geometries to the dielectric construction. Request the approved laminate, prepreg, copper and finish within a single manufacturing specification.

Published limits: The table gives 4 mil standard laser drilling and 3 mil drilling subject to evaluation with a single 106 prepreg condition. It also lists 65/65 micrometre trace/space. General board aspect-ratio figures must not be treated as microvia aspect ratios.

Applications, standards and testing: The service covers customer requests for HDI boards including prototypes and small-batches, subject to the supplier’s acceptance. Published inspection methods include AOI, electrical testing and microsections. Verify the required class and test reports for this order.

Strength and purchasing caution: Detailed evaluation notes make screening easy. Those notes should be reviewed before using an advanced capability number in PCB design. Request manual engineering approval for the stack-up especially when multiple minimum features are present on the same board.

Official website: https://www.pcbway.com/

20. NextPCB

Company, founding and headquarters: NextPCB shows a manufacturing operation in China. The brand’s founding and exact headquarters couldn’t be confirmed with certainty from the reviewed HDI documents. The group’s history shouldn’t be substituted without clarification.

Introduction and business type: NextPCB offers PCB fabrication and assembly services and describes its manufacturing facilities. The request must indicate the real producer and plant.

HDI products and structures: NextPCB’s HDI page mentions 1+N+1, 2+N+2 and 3+N+3 builds as well as advanced any-layer technologies. Keep these advanced technologies distinct from the standard production path.

Materials and finishes: The published material families contain high-Tg, high-speed and RF focused alternatives. Please state the specific grade, finish and qualification status of the required via architecture.

Published limits: The at-a-glance table separates 3.5/3.5 mil standard trace/space from 2/2 mil advanced features. Other pages use different headline values. This article doesn’t combine the most aggressive trace, hole and layer figures into one guaranteed specification.

Applications, standards and testing: Published uses include compact, industrial and automotive electronics. Quality-system claims and Class 3 capability wording require current plant documentation and an agreed order-level test plan.

Strength and purchasing caution: The standard/advanced distinction provides a useful enquiry format. Ask NextPCB to return one dated capability table and signed stack-up for the actual order. Minimum quantity, prototype approval, production lead time and any subcontracted operations must be confirmed commercially.

Official website: https://www.nextpcb.com/

Process-Limit Compatibility Matrix: Which HDI Numbers Belong Together?

The Process-Limit Compatibility Matrix keeps each numerical limit attached to the conditions that make it usable. It’s a buyer’s comparison method, not a new manufacturing standard. Use it for a manufacturability review of the hdi pcb manufacturing process before fixing the final layout.

A minimum trace width describes a conductor. Trace spacing describes the gap beside it. Laser drill diameter, finished hole diameter, capture-pad diameter and component pitch describe different features. Replacing one with another can make a dense BGA fanout look manufacturable when the required annular area or registration allowance is missing.

TTM’s example helps explain this more clearly. TTM’s example makes the distinction concrete: approximately 100 micrometres for a laser-drilled via and approximately 200 micrometres for its pad. Your layout can’t be said to reserve an interconnection footprint by simply reserving a hole diameter. Use the definitions of the dimensions provided by the fabricator, whether the value applies before or after plating. Common HDI PCB technology includes different via structures; the materials used in HDI must be approved for the chosen process. The advantages of HDI can include higher interconnect density and, where the layout supports it, reducing signal path lengths.

According to the agreed-upon definition, microvia aspect ratio is concerned with the depth-to-diameter ratio of a via. It isn’t the thickness of the board divided by the smallest hole. A mechanically drilled through-hole ratio can’t qualify a laser microvia in a build-up dielectric. If two suppliers use different measurement definitions, you should normalize the definitions prior to comparing the ratios.

Understand 1+N+1, 2+N+2 and 3+N+3 before selecting a factory

Different hdi pcb stack-up structures are used to address different routing concerns. One such concern may be the density. In these structures, HDI may permit both an increase in interconnect density and a reduction in signal path lengths. These benefits apply only to the HDI circuit design. Merely increasing the number of microvias doesn’t improve the product.

N denotes the central multilayer structure, and the outer numbers indicate additional build-up layers on either side. A 1+N+1 configuration has one such layer on either side; 2+N+2 and 3+N+3 configure additional build-up layers. This notation doesn’t show all the electrical connections, via fills or lamination operations. To define via fill or lamination, the selected construction should specify each operation.

Stacked microvias align vertically, while staggered microvias shift their alignment. Any-layer HDI allows more flexibility when designing layer-to-layer interconnection via the chosen construction method. However, this flexibility doesn’t guarantee all possible vias. For more details on this, see PCBark’s description of any-layer hdi pcb structures.

Design tools can check a PCB stackup against entered constructional constraints, but such rules still require approval by a fabrication house. In a standard HDI fanout review, engineers place the components on the top layer and identify the required layer transitions and the routing channels. The resulting HDI stackup should include the connection spans and shouldn’t rely on a software label.

The first obvious question is if a simpler construction meets the escape-routing, signal-integrity and mechanical requirements. More build-up stages will probably increase the fabrication steps and the work required to qualify the construction. They may also allow a smaller or lower-layer-count HDI solution. Compare the complete alternative solutions instead of assuming that HDI is always the cheaper or more expensive, or always more reliable, construction.

How Should Materials, Copper and Impedance Be Specified?

HDI pcb design and manufacturing rely on a compatible material set. An HDI material request is more elaborate than “FR-4” or “high frequency.” One needs to state the laminate grade, build-up dielectric, copper thickness, finished board thickness and permitted substitutions. The fabricator needs to evaluate that combination against drilling, desmear, plating, bonding and the intended assembly thermal exposure.

There are various materials with different functions, such as high-Tg FR-4, halogen-free systems, resin-coated copper, polyimide and RF laminates. Systems with high glass-transition temperature don’t necessarily have the best dielectric expansion behavior or loss characteristics for the design. Likewise, a low loss material name doesn’t verify a proposed hybrid stack-up has a released microvia process.

HDI PCB laminates must be reviewed at the appropriate stage of fabrication. For an RF PCB or microwave PCB, indicate the PCB material grade and the corresponding electronic requirements. The vendor must verify that the material is supported by their drilling, bonding and copper plating processes. HDI compatibility of general RF materials can’t be assumed.

The copper weight or thickness must be specified in the request. Clarify whether each value refers to starting Cu foil or finished copper after plating. Fine conductor spacing can be affected by this. A supplier’s thin copper minimum shouldn’t be specified in combination with a heavy finished copper requirement without explicit approval.

This distinction is helpful when significant amounts of heavy copper are used on part of the board. Determine if local fine-line features and thicker conductors can use the proposed process. If not, the construction may require a different arrangement. Advanced PCB processing integrates several techniques and shouldn’t be used as a permission slip to use any and all extreme techniques advertised.

If you want to use controlled impedance, give the target values and tolerances, layering, transmission-line structures and the operating conditions. Agree on the design and measurement of coupons. The fabricator should provide dielectric thicknesses and the dimensions of the conductors that were used in the approved calculation. PCBark’s high-speed HDI application guide has related information.

Surface finishes also need to be reviewed. There are different requirements for each application; a list of available finishes is only a preliminary list. Indicate the surface finish on the fabrication drawing and verify its suitability with the component pitch, assembly, storage, and inspection requirements.

HDI Evidence Passport: What Proves a Supplier Is Ready?

The HDI Evidence Passport is a concise document that links the producing factory, board construction, and acceptance package. It avoids treating a certificate, a successful prototype, and a capability brochure as equivalent evidence. Complete the record with the supplier’s engineering and quality teams prior to releasing production.

IPC’s microvia reliability warning describes failures that can occur after a bare-board is accepted, during operation and after assembly reflow. It comes accompanied with a caution against relying on conventional inspection alone for weak microvia interfaces. A shipment continuity pass addresses an even more limited scope in regard to the full lifecycle of the product as compared to reliability.

In regard to copper filled stacked microvias, Yan Ning’s University of Maryland research addresses void geometry, aspect ratio, dielectric expansion, and the microvia-to-target interface. The modeling of lifetime effects is useful for understanding failure mechanisms, but shouldn’t be used to predict a field failure percentage for any of the manufacturers in this list.

Automated optical inspection checks visible pattern features at the appropriate processing stage. Electrical testing verifies the intended connections and isolation. Microsections reveal selected physical features and impedance testing examines the agreed transmission-line properties. Each provides relevant information, though none should be regarded as a replacement for the others.

A historical NIST study of a flip-chip HDI substrate illustrates why the failure location matters: its microvias showed little permanent deformation and no visible cracking under the reported conditions, while other package interfaces cracked. This specific experiment does not establish a universal modern microvia lifetime or qualify any supplier in this directory.

To qualify a stacked-microvia design, determine how the test structure relates to the proposed construction of the board. Relevant questions would also address the number of stacked interfaces, via-on-buried-via arrangement, fill process and material, and thermal exposure. Agree on the test method, coupon design, quantity to be tested, and acceptance criteria with the responsible engineering team. It isn’t necessary to develop a universal cycle count in order to make two quotes comparable.

A production sample also requires a transfer plan. If a volume order moves to a different plant or a different laminate, find out which qualification remains applicable and which needs to be done again. The acceptance of a prototype is valuable evidence for the process that constructed it; the customer must establish the basis for applying the process to another case.

Therefore, a PCB prototype should provide more than a functional pass result. Indicate the route of production and what quality standards were applicable for acceptance. This prototype will be useful for assessing whether the supplier has the capability of specified hdi pcb manufacturing solutions and assessing repeatable interconnect solutions.

Which Standard Revisions Matter to a 2026 HDI Enquiry?

The purchase specification needs to name a standard, revision, product class and applicable addendum. ‘IPC compliant’ isn’t sufficient for acceptance criteria. A quality-management certificate and an IPC product requirement refer to different things and must be located in separate sections of the supplier record.

On the September 2026 review, the publisher’s document revision table listed revisions for IPC-6012 Revision F (September 2023) and IPC-A-600 Revision M (May 2025). It also listed the FA automotive addendum, dated December 2025. Confirm the agreed revision when placing an order; a supplier’s older offer template may quote the use of different revisions.

The same table marks IPC-2226 Revision A as no longer maintained and IPC-6016 as superseded. Unmaintained documentation doesn’t automatically invalidate an existing contractual reference. Buyers shouldn’t refer to these documents as newly updated 2026 standards. The involved technical personnel should resolve the applicable document(s).

The publisher’s IPC-6012F release explanation identifies changes addressing microvia structures and coupons for complex interconnections. This is a reason to review the actual qualification package, rather than treating a Class 3 phrase on a website as a complete test plan.

A buying signal for 2026 is emphasizing comfortable production rules over headline minima. In a May 2026 manufacturing article, Anaya Vardya writes:

“Minimum capability is not a design target.”

The most practical next step is to determine which geometry the proposed factory produces routinely for the defined material and quantity of the order, and if there are any exceptions, those would warrant a close review. Read the author’s fabrication advice.

Quote Assumption Delta Sheet: Compare the Same Board

The Quote Assumption Delta Sheet explains why two HDI offers are different prior to selecting the lower total. It doesn’t provide a fabricated market price. Actual supplier offers should be made against one approved file set, and the bidders should be asked to price the unresolved differences.

Send Gerber or the agreed intelligent manufacturing data, drill files and via map, fabrication drawing, stack-up, netlist, impedance requirements and order quantities. For assembly, include the bill of materials, placement data and required components. Mark the manufacturing files with a controlled revision so that Engineering clarifications don’t silently change only one bidder’s scope.

An example is two different quotes for the same nominal 2+N+2 board with different laminate grades, via fill and inspection reports. These aren’t observed quotes. These are illustrative examples, and must be addressed before comparison of quotes can be done. Only then can we decide if one quotation is more economical than the other.

Reduce costs while final design decisions can still be resolved. Consider simplifying the build design or relaxing geometry requirements for improved panel utilization, provided the actual electrical and mechanical requirements are satisfied. Evaluate means and methods to be employed to improve material utilization and improve delivery while minimizing cost. Retain the required reliability and acceptance scope while evaluating alternatives.

Inquire how prototype approval leads to repeat production. The quotation must state assumptions for minimum order quantity, repeat order, reserved / unreserved production capacity, Engineering response, and the disposition of non-conforming boards. Of these assumptions, none can be derived from a generic “fast turnaround” claim.

A quick turn PCB enquiry should provide all the technical data the same as a scheduled order. Preventing a rush request from coming to engineering with unaddressed material or via questions requires consideration of HDI routing as early as possible in the design process. For high density interconnect pcbs, the promised turnaround should begin at a well-defined release event rather than at an initially uploaded fuzzy file.

In the case where the choice is still between conventional multilayer and HDI construction, check the HDI versus multilayer PCB comparison before requesting the final pricing. This design choice can change the range of potential suppliers.

Frequently Asked Questions About HDI PCB Manufacturers

Build the Shortlist Around an Approved Construction

The best outcome of a manufacturer comparison is a smaller set of suppliers that can answer the same technical and commercial questions. Keep the company name, actual producing site and approved process together. Then assess the returned stack-up, qualification evidence, test package and delivery terms as one offer.

References & Sources

Manufacturer profiles use the official company pages and corporate disclosures identified in the research review. Their full web page addresses appear as plain text in each profile. The technical sources below explain reliability mechanisms, standards and manufacturing judgment; none independently certifies the 20 suppliers.

• IPC: warning on printed-board microvia reliability (2019).
• Yan Ning, University of Maryland: reliability of Copper-Filled Stacked microvias in high density interconnect circuit boards (2017 dissertation).
• Ning, Azarian and Pecht: Influence of Plating Quality on reliability of microvias (2015; related work from the same research group).
• IPC document revision table (reviewed September 8, 2026).
• IPC-6012F release and scope explanation (October 2023).
• Anaya Vardya: ultra-HDI design guidance from the fabrication floor (May 2026; manufacturer-authored technical commentary).