Bare PCB Prototype Fabrication
PCB Prototype
Manufacturing Capabilities
Review our prototype PCB specifications for layer counts, materials, copper thickness, trace spacing, drilling and controlled impedance. Compare your requirements below, or send your fabrication files for engineering review.
- Materials & Stackups
- Fabrication Specifications
- Engineering Review Conditions
Before You Compare Specifications
How to Read Our
Prototype Capabilities
Use the specifications on this page to compare your bare PCB design with our prototype manufacturing capabilities. Read each value together with its material, copper thickness and process conditions.
This page focuses on fabrication limits and review requirements. For an overview of the service, visit our PCB prototype services page.
Check the Conditions Behind Each Value
Trace spacing, drill sizes and tolerances depend on the material, stackup, copper thickness and board construction. Individual minimum and maximum values are not necessarily available in the same design.
Identify Requirements That Need Review
Specifications marked as requiring engineering review are not unconditional manufacturing commitments. Submit the relevant files and requirements so the proposed construction can be assessed.
Confirm the Complete Fabrication Specification
Include your material, stackup, finished copper requirements, impedance targets and special features with the fabrication files. Final manufacturability is confirmed through engineering review.
Prototype Fabrication Overview
PCB Prototype Capabilities at a Glance
Compare the key specifications below with your design. Each capability must be read together with its copper thickness, board construction and engineering review conditions.
Swipe horizontally to view the complete table.
| Parameter | Prototype Capability | Conditions & Review Notes |
|---|---|---|
| Layer count | 1–36 layers | Confirm the complete stackup and construction. See our multilayer PCB prototype service. |
| Finished board thickness | 0.1–8.0 mm | Thickness below 0.2 mm or above 6.5 mm requires engineering review. Surface-finish thickness limits must also be checked. |
| Maximum finished copper | Outer layers: 8 oz Inner layers: 6 oz | Higher copper weights require review. Trace and spacing requirements depend on copper thickness. View our PCB copper thickness capabilities. |
| Minimum inner-layer trace / space | 2 / 2 mil At 18 μm finished copper thickness Engineering review required | Not a universal limit for all copper weights. At 35 μm finished copper, the listed capability is 3 / 3 mil. |
| Minimum outer-layer trace / space | 2 / 2 mil At 12 μm base copper thickness Engineering review required | Base copper and finished copper are different specification references. At 35 μm base copper, the listed capability is 5 / 5 mil. |
| Mechanical drilling | 0.1–6.5 mm tool diameter 0.1 mm drilling requires review | The 0.1 mm drill condition applies to board thickness ≤1.0 mm. Tool diameter is not a finished plated-hole diameter specification. |
| Laser-drilled via diameter | 4 mil standard 3 mil subject to review | The 3 mil condition is listed for a single 106 prepreg ply. Material and dielectric construction must be confirmed. |
| HDI laser build-up stages | 1–6 stages Stage 6 and above require review | High-speed HDI is separately listed at 1–3 stages. Discuss the construction through our HDI PCB fabrication service. |
| Controlled impedance tolerance | ±5 Ω below 50 Ω ±10% at 50 Ω and above | ±8% at 50 Ω and above requires review. Include targets and stackup requirements for controlled impedance PCB fabrication. |
| Smallest finished board | 2.5 × 2.5 mm Supplied in a panel / set | Individual-board delivery is listed for dimensions above 10 × 10 mm. Confirm the delivery format with the fabrication files. |
Materials & Board Construction
Prototype PCB Materials & Stackup Options
Material selection and stackup construction should be reviewed together. Specify your required laminate grade, copper thickness and dielectric structure so the prototype can be assessed against the intended fabrication process.
FR-4 Laminates
Conventional FR-4 Options
FR-4 options are available for prototype constructions. Include the required material grade, finished board thickness and copper specification rather than specifying “FR-4” alone.
Compare the available PCB material options when preparing your fabrication requirements.
Special FR-4 Grades
High-Tg, Halogen-Free & High-CTI
The material range includes high-Tg, halogen-free and high-CTI grades. State the properties required for your design; these categories should not be treated as interchangeable specifications.
Review high-Tg PCB materials and identify any additional material requirements in your fabrication notes.
RF Material Options
High-Frequency Laminates
RF material options include Rogers, Taconic and Arlon laminate families, with PTFE and ceramic-filled grades listed in the material range. Specify the exact grade and construction for review.
Explore our high-frequency PCB fabrication service for RF board requirements.
High-Speed Material Options
Low-Loss Multilayer Constructions
High-speed laminate options can be reviewed with your layer stackup and impedance requirements. Include the laminate designation and dielectric construction, not only the target data rate.
Provide the proposed construction for pre-production engineering review.
Define the Complete Stackup
A layer count alone does not define the board construction. Include the material and copper requirements for each layer, along with the via structure and any controlled impedance requirements.
- Materials: laminate grade, core and prepreg requirements, and any permitted substitutions.
- Copper and thickness: base or finished copper reference, dielectric thicknesses and finished board thickness.
- Via construction: through, blind or buried vias, laser-drilled features and backdrilling requirements.
- Electrical requirements: impedance targets, tolerances and the layers to which they apply.
Material families listed here do not indicate live stock. Confirm the exact grade, availability, approved substitutions and any procurement-related lead time during quotation. Ceramic-filled RF laminates should not be interpreted as a claim of solid ceramic PCB manufacturing capability.
Detailed Manufacturing Specifications
PCB Prototype Fabrication Specifications
Review the specifications by process category. Copper references, material restrictions and review conditions are included alongside the relevant values.
Swipe within each table to view all columns.
Layers, Board Thickness & Dimensions
| Parameter | Capability | Conditions |
|---|---|---|
| Layer count | 1–36 layers | Stackup and process combination subject to review. |
| Board thickness | 0.1–8.0 mm | Below 0.2 mm or above 6.5 mm requires review. |
| Smallest finished board | 2.5 × 2.5 mm | Panel / set delivery. Individual-board delivery is listed for sizes above 10 × 10 mm. |
| Large-format dimensions | 21 × 33 inches for 2–20 layers; 1000 mm length also listed | Confirm the applicable construction and finish. A short side above 21 inches requires review; these entries do not define one combined maximum rectangle. |
| Finished copper thickness | Minimum: 0.5 oz Maximum: outer 8 oz / inner 6 oz | Above the listed maximum copper weights requires review. |
| Lamination cycles per core | High-Tg FR-4: up to 6 High-speed materials: up to 3 | Material-specific limits; not interchangeable with HDI laser build-up stages. |
Copper Thickness, Trace Width & Spacing
Values are shown as trace width / spacing in mil. Inner-layer values reference finished copper; outer-layer values reference base copper.
| Finished Copper | Trace / Space | Review |
|---|---|---|
| 18 μm / 0.5 oz | 2 / 2 mil | Required |
| 35 μm / 1 oz | 3 / 3 mil | Per construction |
| 70 μm / 2 oz | 4 / 5 mil | Per construction |
| 105 μm / 3 oz | 6.5 / 6.5 mil | Per construction |
| 140 μm / 4 oz | 8 / 8 mil | Per construction |
| 175 μm / 5 oz | 10 / 10 mil | Per construction |
| 210 μm / 6 oz | 12 / 12 mil | Per construction |
| Base Copper | Trace / Space | Review |
|---|---|---|
| 12 μm / ⅓ oz | 2 / 2 mil | Required |
| 18 μm / 0.5 oz | 3 / 3 mil | Per construction |
| 35 μm / 1 oz | 5 / 5 mil | Per construction |
| 70 μm / 2 oz | 8 / 8 mil | Per construction |
| 105 μm / 3 oz | 10 / 10 mil | Per construction |
| 140 μm / 4 oz | 10 / 13 mil | Per construction |
| 175 μm / 5 oz | 12 / 15 mil | Per construction |
| 210 μm / 6 oz | 15 / 15 mil | Per construction |
For finished copper above 70 μm with limit-level etch compensation, the listed process excludes 1.5 oz, 2.5 oz and 3.5 oz base copper. Confirm the copper construction before applying the minimum trace rules.
Mechanical Drilling, Laser Vias & HDI
| Parameter | Capability | Conditions |
|---|---|---|
| Mechanical drill tool | 0.1–6.5 mm | 0.1 mm requires review. |
| Drill / board thickness | 0.1 mm / ≤1.0 mm 0.15 mm / ≤1.6 mm 0.2 mm / ≤2.4 mm | Apply the relevant board-thickness condition; 0.1 mm drilling remains subject to review. |
| PTFE / hybrid drilling | Mechanical blind holes: 0.15 mm Through holes: 0.2 mm | Material-specific drilling limits. |
| Board thickness / hole diameter ratio | Up to 14:1 | Above 14:1 requires review. |
| Laser-drilled holes | 4 mil standard 3 mil subject to review 8 mil maximum | 3 mil: single 106 prepreg ply. The 8 mil entry applies to dielectric thickness ≤0.15 mm. |
| Laser build-up stages | 1–6 stages | Stage 6 and above require review. High-speed HDI is listed separately at 1–3 stages. |
| Resin plugging — board thickness | 0.254–6.5 mm | Double-sided PTFE requires review. Hybrid and all-PTFE multilayer constructions are listed as supported. |
| Resin plugging — hole diameter | 0.254–6.5 mm | Specify the required fill and finished surface condition. |
| Through-hole filling | Board thickness ≤0.6 mm Hole diameter ≤0.2 mm Fill saturation ≥70% | Other conditions require review. Do not interpret this entry as a 100% void-free fill commitment. |
| Controlled-depth drilling | Plated holes: 0.15 mm Non-plated holes: 0.25 mm | Minimum listed drilling diameters. |
| Backdrill depth tolerance | ±0.02 mm | Listed target-to-next-layer dielectric separation: ≥0.10 mm. |
| Castellated / half-hole drill | 0.3 mm minimum tool diameter | Confirm the finished edge construction. |
| Finished BGA pad diameter | 5 mil minimum | Below 5 mil requires review. |
| BGA escape trace / clearance | Trace: 2.4 mil Pad-to-trace clearance: 2.2 mil | Trace width below 2.4 mil requires review. |
Impedance, Thickness & Mechanical Tolerances
| Parameter | Capability | Conditions |
|---|---|---|
| Double-sided board thickness | ±0.05 mm | Board thickness ≤3.0 mm. |
| 4-layer board thickness | ±0.05 mm | Board thickness ≤1.0 mm. |
| 6-layer board thickness | ±0.075 mm | Board thickness ≤1.2 mm. |
| Other board-thickness cases | ±10% | Tighter requirements need review. |
| Impedance below 50 Ω | ±5 Ω | Provide target values and relevant layers. |
| Impedance at or above 50 Ω | ±10% ±8% subject to review | Confirm stackup and tolerance before fabrication. |
| Layer-to-layer registration | ≤3 mil | Listed registration capability. |
| Hole position versus CAD | ±3 mil; limit: 2 mil | State any limit-level requirement for confirmation. |
| Press-fit hole diameter tolerance | ±2 mil | Include finished hole requirements. |
| NPTH diameter tolerance | ±2 mil | Include required non-plated hole sizes. |
| Profile dimensional tolerance | ±0.1 mm | Limit ±0.05 mm requires review. |
| Controlled-depth NPTH routing | ±0.15 mm depth tolerance | Applies to the listed slot / edge process. |
| Warpage | Standard: 0.75% Limit: 0.5% Maximum: 2.0% | State the required acceptance value in the fabrication specification. |
| V-cut board thickness | 0.4–3.2 mm | Above 3.2 mm requires review. |
| Routed copper clearance | Outer layers: 6 mil Inner layers: 10 mil | Minimum listed clearance for routing without exposed copper. |
Surface Finishes, Solder Mask & Marking
| Parameter | Capability | Conditions |
|---|---|---|
| Surface finish options | Lead-free HASL, ENIG, immersion tin, immersion silver, OSP, hard gold, ENEPIG | Combination finishes and gold fingers are also listed; confirm the selected process. |
| ENIG plating | Nickel: 100–200 µin Gold: 1–4 µin | Gold thickness ≥4 µin requires review. |
| ENEPIG plating | Nickel: 100–200 µin Palladium: 1–6 µin Gold: 1–4 µin | Confirm the required plating specification. |
| Hard gold / gold fingers | 2–50 µin | Above 50 µin requires review. |
| Selective gold plating | 2–50 µin | Above 50 µin requires review. Local gold above 30 µin with trace / space below 0.10 mm also requires review. |
| Other coating thicknesses | HASL: 1–40 μm Immersion tin: 0.8–6 μm Immersion silver: 6–12 µin OSP: 0.2–0.4 μm | Use the units shown for each finish; µin and μm are not interchangeable. |
| Finish-specific board thickness | ENIG: 0.2–6.5 mm Horizontal immersion tin: 0.3–3.0 mm Silver / OSP: 0.3–3.0 mm HASL: 0.6–3.5 mm Hard gold: 0.2–5.0 mm | HASL below 0.4 mm requires review. Confirm other thicknesses outside the listed process ranges. Hard-gold entry includes a listed 10:1 thickness / hole ratio condition. |
| Finish processing dimensions | ENIG: 520 × 800 mm Vertical immersion tin: 500 × 600 mm HASL: 520 × 650 mm Hard gold: 450 × 500 mm | Silver / OSP: listed side length <500 mm. Confirm panel size and finish together. |
| Minimum solder mask dam | Green: 4 mil Other colors: 5 mil | Finished copper ≤1 oz. Dams below 4 mil require review. |
| Solder mask colors | Green, yellow, black, blue, red, white, matte green, matte black, orange | Other color options subject to confirmation. |
| Minimum legend line / height | 1 oz finished copper: 4.5 / 23 mil 2 oz: 5 / 30 mil 3 oz: 6 / 45 mil | Values shown as line width / character height. |
| Peelable mask thickness | 0.2–6.0 mm | Specify required coverage and thickness. |
| Solder mask plugging diameter | 0.5 mm maximum | Different from resin plugging. |
| Printed identification | Serial numbers, barcodes, QR codes | Listed for white legend printing. |
Individual specifications must be checked as a complete construction. A listed limit for drilling, copper, dimensions or surface finish does not automatically apply to every other process combination.
Special Requirements & Process Limits
Requirements That Need Engineering Review
If your design uses a limit-level feature or combines demanding specifications, flag it when requesting a quote. Engineering review determines the feasible construction rather than assuming every listed capability can be combined.
Fine Traces & Small BGA Features
Review is required for 2 / 2 mil inner traces at 18 μm finished copper, or outer traces at 12 μm base copper. Finished BGA pads below 5 mil and BGA escape traces below 2.4 mil also require review.
Include: copper specifications, affected layers and the relevant fine-feature locations.
Small Drills & High Aspect Ratios
Flag 0.1 mm mechanical drilling, 3 mil laser holes and board thickness / hole diameter ratios above 14:1. The listed small-hole conditions must be checked against board and dielectric thickness.
Include: drill files, finished hole requirements, board thickness and via layer spans.
Advanced HDI & Material Combinations
Laser build-up stage 6 and above requires review. High-speed HDI is separately listed at 1–3 stages. PTFE and ceramic-filled RF constructions must follow the material-specific drilling and lamination route.
Include: the complete stackup, laminate grades and proposed blind / buried via construction.
Thickness, Copper & Large Formats
Review is required for board thickness below 0.2 mm or above 6.5 mm, finished copper above 8 oz outer / 6 oz inner, and a board short side above 21 inches. Large formats must also fit the selected finish process.
Include: board and panel drawings, copper weights, surface finish and delivery format.
Tighter Tolerances
Requests for ±8% impedance at 50 Ω and above, ±0.05 mm profile dimensions, or board-thickness tolerances tighter than the applicable listed values require review.
Include: target values, applicable layers or dimensions and the required acceptance criteria.
Special Filling, Plating & Masking
Flag double-sided PTFE resin plugging, through-hole filling outside the listed conditions, hard gold above 50 µin, and ENIG gold at 4 µin or above. Solder mask dams below 4 mil also require review.
Include: fill requirements, plating thickness and units, mask color and affected features.
Have a Requirement Outside the Listed Range?
Submit your fabrication files and identify the non-standard requirements. Check our PCB manufacturing file requirements before requesting a quote.
Engineering review is an assessment, not a guarantee that an out-of-range specification can be manufactured. Any approved construction, specification changes and delivery requirements must be confirmed before production.
Plan the Next Manufacturing Stage
From Prototype to Low-Volume PCB Fabrication
A successful prototype is the starting point for the next manufacturing stage. Before a pilot run or repeat small-batch order, confirm that the approved design, materials and process requirements are suitable for the planned production quantity.
Use our low-volume PCB fabrication service to plan the transition. Identify any prototype-specific approvals and confirm whether they remain applicable to the next order.
Confirm Materials & Stackup
Review laminate grades, approved substitutions, dielectric construction, copper thickness and impedance requirements. Do not assume that a material change is acceptable without approval.
Recheck Limit-Level Features
Identify fine traces, small holes, advanced HDI, special filling and tight tolerances. Confirm the process window for the intended quantity rather than carrying over a prototype exception automatically.
Release the Production Revision
Supply the approved fabrication revision, quantity, panel requirements, acceptance criteria and requested documentation. Clearly identify changes made after prototype evaluation.
Production transfer does not automatically require a redesign. It requires confirmation that the approved construction, process conditions and delivery requirements apply to the next manufacturing stage.
From File Review to Delivery Requirements
Engineering Review & Bare-Board Verification
Capability values are only part of the fabrication specification. Define what must be reviewed, inspected and documented so the finished bare boards can be assessed against the agreed requirements.
01 / Before Fabrication
Review the Manufacturing Data
Submit a consistent fabrication package and identify requirements that cannot be changed without approval. Resolve file conflicts and construction questions before production release.
- Fabrication revision, Gerber and drill data
- Materials, stackup and copper requirements
- Special vias, tolerances and impedance targets
See our pre-production engineering review information.
02 / Fabrication Planning
Identify Critical Process Features
Flag the features that need particular attention rather than relying on a general note such as “high quality” or “tight tolerance.”
- Fine traces, small holes and registration limits
- Fill condition, surface finish and plating requirements
- Profile dimensions and warpage acceptance values
Include these priorities with the order requirements. View our quality management overview.
03 / Bare-Board Verification
Confirm Inspection & Test Requirements
State the required verification scope for the bare board. Keep electrical continuity requirements, dimensional checks and impedance verification separate in the fabrication specification.
- Required electrical inspection or test scope
- Critical dimensional and finished-hole checks
- Impedance verification where specified
Review our bare PCB testing and inspection information.
04 / Delivery Documentation
Agree on the Required Records
Identify documentation needs at quotation, including any customer-specific format or approval requirement. Do not assume every inspection record is included automatically with every order.
- Requested test and inspection reports
- Material or plating documentation, if required
- Revision identification and acceptance records
Requested records, availability and any associated cost or lead time should be confirmed before order placement.
Include Acceptance Criteria with Your RFQ
Provide the fabrication files, special requirements and requested verification records together. This helps define the review scope before the manufacturing specification is finalized.
Prepare Your Fabrication Package
Files Required for a Prototype Capability Review
Send the fabrication data together with the requirements that define your board. Identify any unresolved items explicitly instead of leaving critical specifications open to interpretation.
Fabrication Files
- Gerber files and matching drill data.
- Board outline and fabrication drawing, where applicable.
- Stackup drawing with layer identification.
- Clear part number and fabrication revision.
Materials & Specifications
- Laminate grade and permitted substitutions.
- Finished board thickness and copper requirements.
- Surface finish, solder mask and legend requirements.
- Impedance targets, tolerances and applicable layers.
Quantity & Special Instructions
- Requested quantity and individual-board or panel delivery.
- Target delivery date and any scheduling constraints.
- Special vias, resin plugging, backdrilling or tight tolerances.
- Acceptance criteria and requested inspection records.
Before submitting, check our PCB manufacturing file requirements. Use the same revision across the files and drawings, and flag any specification that must not be changed without your approval.
Submit a Prototype RFQCommon Engineering Questions
PCB Prototype Capabilities FAQ
Quick answers to common questions about prototype specifications, process limits and engineering review.
What layer counts do you support for prototype PCBs?
Our listed prototype capability covers 1–36 layers. The proposed stackup, materials, copper thickness and via construction must be checked together. This layer range is not an unconditional specification for every board type or material combination.
What is your minimum prototype trace width and spacing?
The listed minimum is 2 / 2 mil, subject to engineering review: inner layers at 18 μm finished copper, or outer layers at 12 μm base copper. Other copper thicknesses have different limits. Review the copper-specific trace and spacing tables rather than applying 2 / 2 mil to every layer.
Is the minimum drill size the finished plated-hole diameter?
No. The listed mechanical drill-tool range is 0.1–6.5 mm, and tool diameter must not be used as a finished plated-hole specification. The 0.1 mm drill condition applies to board thickness ≤1.0 mm and requires engineering review. Include finished hole sizes and tolerances in your fabrication requirements.
Can you manufacture HDI prototype PCBs?
Yes. The listed laser build-up range is 1–6 stages, with stage 6 and above requiring review. High-speed HDI is separately listed at 1–3 stages. Material-specific restrictions apply to PTFE and ceramic-filled RF constructions, so conventional laser-HDI rules should not be assumed to apply to those materials.
What controlled impedance tolerances are available?
The listed tolerance is ±5 Ω for targets below 50 Ω and ±10% for targets at or above 50 Ω. A tolerance of ±8% at 50 Ω and above requires engineering review. Specify the target impedance, tolerance, relevant layers and proposed stackup with your fabrication files.
Can all minimum and maximum specifications be combined?
No. Individual capability values do not define a guaranteed combined construction. Material, copper thickness, board dimensions, hole structure, surface finish and tolerances must be evaluated together. See the requirements that need engineering review before requesting a limit-level combination.
Are prototype capabilities automatically applicable to low-volume production?
No. Confirm the construction and any prototype-specific approvals before pilot runs or repeat small-batch orders. This does not automatically mean the design needs to change. Our low-volume PCB fabrication service provides the next step for discussing the intended quantity and manufacturing requirements.
What should I submit for a prototype capability review?
Submit Gerber and drill files with the board outline, stackup, material grade, copper requirements, surface finish and quantity. Include impedance targets, special features, tolerances and requested documentation where applicable. Use the RFQ file checklist to prepare a consistent fabrication package.
Move from Specifications to Review
Check Your PCB Design Against Our Prototype Capabilities
Send your fabrication files and key requirements to discuss the proposed construction. Flag special features, tight tolerances and any specifications that require engineering confirmation.
Final manufacturability, approved specifications, pricing and delivery requirements are confirmed for the proposed order.