HDI Printed Circuit Boards | HDI Layout

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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.

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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 be etched.	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 be etched.	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.

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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

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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.

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