Skip to main content

HDI Printed Circuit Boards for Smaller, Faster, Extremely Reliable Products

Sierra Circuits manufactures and assembles high-density interconnect PCBs with blind, buried, and micro-vias, built-up laminations, and the highest signal integrity in the industry.

Start a Custom Quote
Product image 1: HDI PCBs

You may be surprised how cost-effective the right HDI layout can be.

HDI PCB costs can be reduced when your stack-up is properly planned out. Additionally, design efficiencies in HDI production mean faster time-to-market. And in terms of reliability, microvias out-perform typical through-holes almost every time.

Ready to start building with HDI PCBs? Engineers at Sierra Circuits can help you efficiently prototype and manufacture your HDI PCBs, right here in the U.S.

Start a Custom Quote

Product Promise

Sierra Circuits manufactures your HDI PCBs with full intellectual property protection.

High tech in small form:

  • Special stack-up help / NPI review
  • Up to 30 layers
  • Files evaluated by engineers
  • Quote sent by email within a few hours

HDI features:

  • Down to 1.5-mil trace space, 2-mil holes
  • Blind vias, buried vias, and other microvia techniques
  • Built-up laminations and high-signal performance considerations
  • Laser direct imaging
  • Fine lines and via-in-pad technology
  • Metal-core
  • Flex / rigid-flex

Certified for your industry:

  • Mil-spec
  • Automotive
  • Aerospace and defense
  • Medical devices

Via capabilities for HDI PCBs

Via Type Via parameter Sierra Circuits capability
Blind Via Min total pad size 4 mils (.102 mm) over drill size
Min laser drill size 4 mils (.102 mm)
Mechanically drilled annular ring 4 mils (.102 mm) over drill size
Dielectric material thickness 2 mils (.051 mm)
Capture pad size 4 mils (.102 mm) over drill size
Laser aspect ratio .75:1
Buried Via Min total pad size 5 mils (.127 mm) over drill size
Min drill size 6 mils (.152 mm) – depending on aspect ration
Capture pad size 5 mils (.127 mm) over drill size
Laser aspect ratio .75:1
Through Hole Min total pad size 5 mils (.127 mm) over drill size
Min drill size 6 mils (.152 mm)
Capture pad size 5 mils (.127 mm) over drill size
Max layer count 26+
Min finish thickness .01″ (.254 mm)
Min trace width (I/L) 3 mils (.076 mm)
Min trace width (O/L) 3 mils (.076 mm)
Min space width (I/L) 3 mils (.076 mm)
Min space width (O/L) 3 mils (.076 mm)
Max lamination cycles 4
Min hole size 6 mils (.152 mm)
Min pitch .157″ (.4 mm)
Stacked vias Yes
Staggered vias Yes
Conductive filled vias Yes
Non-conductive filled vias Yes
Copper plate shut microvias Yes
Heat sinks Yes
UL 94V-0 (on selected materials) Yes

Quality reports for HDI PCBs

Report type Sierra Circuits capability
Specifications IPC-6012, class 1, 2, 3, & ES Yes
IPC-6013, class 1, 2 & 3 Yes
31032 MIL-PRF-55110 (on selected materials) Yes
Reports / Certificates Micro section Yes
Solderability Yes
X-ray fluorescence Yes
Ionic contamination Yes
Time domain reflectometry (TDR) Yes
First article inspection (FAI) Yes
Certificate of compliance (C of C) Yes
Electrical test Yes

Fabrication parameters for HDI PCBs

Fabrication parameter Sierra Circuits capability
Panel sizes 14×26″ (36×66 cm), 21×25″ (53×64 cm), 21x 29″ (53×74 cm), 12×18″ (30×46 cm), 18×24″ (46×61 cm), 16×18″ (41×46 cm)
Min board thickness .007″ (.178 mm)
Max board thickness .25″ (6.4 mm)
Thickness tolerance < 10%
Bow & twist tolerance < 7%
Min core thickness .002″ (0.51 mm)
Min dielectric .002″ (.051 mm)
Min starting copper foil weight 9 micron (.009 mm)

Preferred materials for HDI PCBs

Material Type Raw board manufacturer Sierra Circuits capability
FR-4 Lead Free Isola 370 HR Yes
Ventec VT47 Yes
Nan Ya NPG-170 Yes
Polyimide Isola P95 Yes
Nelco N7000-2 HT Yes
Arlon 85N Yes
Highspeed FR/MW Applications Isola I-speed Yes
FR 408HRR Yes
Nelco N4000-13 Yes
Nelco N4800-20 Yes
Teflon Nelco N9000-13 RF Yes
Rogers RO3000 Series Yes
Rogers RT/DUROID Series Yes
Rogers ULTRALAM 2000 Yes
Ceramic Rogers RO4003 Yes
Rogers RO4350 Yes
Rogers TTM 3, 4, 6, 10, 10i Yes
Taconics CER-10 Yes
Taconics RF-35, RF-35A2 Yes
Taconics RF-60 Yes
Flex DuPont Pyralux AP Yes
DuPont Pyralux LF Yes
DuPont Pyralux FR Yes
Rigid Laird IMPCB Yes

Drill parameters for HDI PCBs

Drill parameter Sierra Circuits capability
Smallest laser drill diameter .003″ (.076 mm)
Largest laser drill diameter .010″ (.254 mm)
Max laser aspect ratio >.75:1
Min mechanical diameter .005″ (.127 mm)
Max mechanical aspect ratio > 10:1
Min mechanical drill to copper .005″ (.127 mm)
Min plated through hole tolerance +/- .002” (.051 mm)
Min non plated through hole tolerance +/- .001” (.025 mm)

Pad diameter parameters for HDI PCBs

Board Type Placement Sierra Circuits capability
Rigid Inner layer Drill + .008″ (.203 mm) + class 2
Outer layer Drill + .006″ (.152 mm) + class 2
Flex Inner layer Drill + .010″ (.254 mm) + class 2
Outer layer Drill + .008″ (.203 mm) + class 2

Conductor parameters for HDI PCBs

Feature Conductor parameter Sierra Circuits capability
Pad Size Min pad size for electrical test .004″ (.102 mm)
Min wire bond pad size .004″ (.102 mm)
Min Trace Vs Copper Thickness Note: Thickness includes starting foil plus panel plates (for wrap if any) to beetched. 5 microns .002″ (.051 mm)
9 microns .0025″ (.064 mm)
3/8 oz .003″ (.076 mm)
1/2 oz .0035″ (.089 mm)
1 oz .0045″ (.114 mm)
2 oz .006″ (.152 mm)
3 oz .0065″ (.165 mm)
> 3 oz Contact us
Min Space Vs Copper Thickness Note: Thickness includes starting foil plus panel plates (for wrap if any) to beetched. 5 microns .0025″ (.064 mm)
9 microns .003″ (.076 mm)
3/8 oz .0035″ (.089 mm)
1/2 oz .004″ (.102 mm)
1 oz .005″ (.126 mm)
2 oz .0065″ (.165 mm)
3 oz .007″ (.178 mm)
> 3 oz Contact us

Permanent solder mask parameters for HDI PCBs

Type Solder mask parameter Sierra Circuits capability
Liquid Photoimageable (LPI) Colors Green, red, blue, yellow
Gloss Semi-gloss, matte (only in green)
Min dam/web size SMT .004″ (.102 mm)
Min dam/web size BGA .0035″ (0.89 mm)
Clearance >.0005″ (.013 mm)
Mask-defined SMT Or BGA (not ground plane) Yes
Mask-defined features on ground plane Yes
Laser Direct Imaging (LDI) Colors Green, black, red, blue
Gloss Semi-gloss
Min web for SMT .004″ (.102 mm)
Min web for BGA .0035″ (.089 mm)
Clearance .005″ (.126 mm)
Mask-defined SMT Or BGA (not ground plane) Yes

Legend mask parameters for HDI PCBs

Type Legend mask parameter Sierra Circuits capability
Sprint Color White
Min line .050″ (1.27 mm)
Min height .025″ (.635 mm)
Screen Printable Colors White, yellow, black, red
Min line .007″ (.178 mm)
Min height .030″ (.762 mm)

Surface finishes for HDI PCBs

Surface finish Sierra Circuits capability
HASL (vertical & horizontal) Yes
Lead free HASL Yes
OSP (Shikoku F2 & Entek) Yes
ENIG (electroless nickel / immersion gold) Yes
ENEPIG (electroless nickel-electroless paladium-immersion gold) Yes
Immersion silver Yes
Tin nickel No
Electrolytic soft gold Yes
Electrolytic hard gold Yes

Fabrication parameters for HDI PCBs

Fabrication parameter Sierra Circuits capability
Mechanical Min route cutter available .021″ (.533 mm)
Routed part size tolerance <.010″ (.254 mm)
Counter sink Yes
Counter bore Yes
Bevel angles 20, 30, 45
Laser Milling, depth tolerance +/- .003″ (.076 mm)
Laser routed thickness <.032″ (.813 mm) thick
Routed array Yes
V Score Angles 30, 45, 60
Edge to copper .007″ (.178 mm)
Dicing Edge to copper .005″ (.127 mm)
Edge / Castellation Min drill via .010″ (.254 mm)
Edge plating Yes

Other screenable materials for HDI PCBs

Screenable material Sierra Circuits capability
Carbon ink Yes
Peelable solder mask Yes

Electrical tests available for HDI PCBs

Report type Sierra Circuits capability
Controlled impedance 5% w/ F/A
Hi pot Yes
Test voltage 40, 250, 500
Isolation resistance (Mohms) >100
Continuity resistance (Ohms) <.010
Min pad size .004″ (.102 mm)
Trusted by innovators

Engineers at the world’s most innovative companies choose Sierra Circuits for the highest quality microelectronics PCB design and manufacturing, right here in the USA.

Start a Custom Quote and Get to Market Faster

Product Image 2: HDI PCBs

Sierra Circuits engineers and technicians have the experience to bring your HDI layouts to life.

Whether you’re developing medical implantation devices on a tight deadline or you’re a DoD contractor looking to satisfy ITAR regulations, Sierra Circuits manufactures and assembles the most reliable high-density interconnect PCBs in the United States.

Ideal for:
  • Medical miniaturization for devices operating directly with the human body
  • Aerospace and DoD electronics for mission critical functions
  • Highly advanced and sophisticated small form factor products like IoT devices, wearables, and similar portable devices
  • Automotive engineers looking to shore-up their supply chain troubles

Start a Custom Quote

Sierra Circuits is
headquartered in Silicon Valley.
We welcome visitors at
our 70,000 sqft facility,
located at 1108 West Evelyn Avenue
in Sunnyvale, California.
Book a tour with an account manager today!
Let us introduce you to one of the most innovative communities of engineers and designers in the world.
We can help you plan your project from design to assembled board.

Manufacturing Equipment at Sierra Circuits

Our 70,000 sqft state-of-the-art campus in the heart of Silicon Valley contains the most advanced equipment required for the manufacture and assembly of your PCBs. Whether you’re looking for standard quick turn PCBs or boards with the tightest tolerances, made from exotic metals, there’s a reason Sierra Circuits leads the industry in quality and performance.

PCBs manufactured and assembled in the United States

Get started with HDI PCBs

  • Blind vias, buried vias, and other microvia techniques
  • Built-up laminations and high-signal performance considerations
  • Laser direct imaging
  • Fine lines and via-in-pad technology
Start a Custom Quote

Talk to a Sierra Circuits PCB Expert today

24 hours a day, 7 days a week.

Call us: +1 (800) 763-7503
Email us: through our Customer Care form