DFM Checklist for PCB Design
A comprehensive Design for Manufacturability checklist covering every critical check before you submit Gerbers to your CM.
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Design for Manufacturability (DFM) is the practice of designing a PCB so that it can be reliably built at your target contract manufacturer (CM). Poor DFM leads to low yield, expensive re-spins, and delayed product launches. This checklist covers the most impactful checks across six categories — use it before every Gerber release.
Items marked Critical represent failures commonly caught during CM DFM review that cause costly board re-spins or production delays. Address these first.
Trace & Space Rules
0/7- Minimum trace width ≥ 5 mil (standard fab) or per CM specCritical
- Minimum trace/space ≥ 5/5 mil on signal layersCritical
- Power traces sized for current: ≥1 oz Cu, ≥20 mil per amp (rule of thumb)Critical
- Differential pairs routed with matched length and spacing
- No acute angles (< 90°) on traces — use 45° bends
- Controlled impedance traces match target stack-up (e.g., 50Ω ±10%)
- Trace necking under BGAs is within fab capability
Via Design
0/6- Via drill size ≥ 0.2 mm; annular ring ≥ 0.1 mm on each sideCritical
- Via-in-pad: filled and capped (VIPPO) if used under IC padsCritical
- No vias placed inside SMD pads (unless tented/filled)Critical
- Thermal relief vias to planes on through-hole pads for soldering
- Blind/buried vias confirmed with fab capability before design
- Via keepout enforced under BGAs (min 0.1 mm from via edge to pad edge)
Component Placement
0/8- All SMD components within IPC-7351 courtyard boundaries — no overlapsCritical
- Polarized components (caps, diodes) oriented consistently across boardCritical
- No components within 5 mm of board edge (3 mm min for SMD)Critical
- Heavy components (connectors, transformers) have mechanical retention
- Matched thermal mass for 0201/0402 passives in close pairs to prevent tombstoningCritical
- ICs with thermal pads have adequate via array to inner plane for heat dissipationCritical
- Test points accessible from top side; no components within 2.5 mm of test point
- Component height clearance verified against enclosure/mating PCB constraints
Solder Mask & Silkscreen
0/7- Solder mask expansion ≥ 2 mil per side from copper pad edges
- No solder mask slivers < 4 mil between adjacent pads (NSMD preferred for fine-pitch)Critical
- Thermal pad solder paste relief pattern per IC datasheetCritical
- No silkscreen over pads or exposed copperCritical
- Reference designators legible at 1:1 scale; font height ≥ 40 mil
- Board revision, part number, and date code on silkscreen
- Pin 1 indicators and polarity markers present on all relevant components
Panelization & Fiducials
0/6- Panel V-score or tab-route score lines specified and documented
- Minimum 3 global fiducials on panel (ideally 3 per board for small boards)Critical
- Fiducials: 1 mm copper circle, 3 mm clearance, on all paste/pick-and-place layersCritical
- Board outline on mechanical layer is closed (no gaps)Critical
- Edge connectors and castellated holes flagged in fab notes
- Panelization confirmed with CM before committing to layout
Design Rule Check (DRC)
0/7- Zero DRC errors in EDA tool with CM-specific rules loadedCritical
- ERC (Electrical Rules Check) passed — no unconnected nets, no shortsCritical
- Netlist comparison (schematic vs layout) passes — no missing connectionsCritical
- Gerber files reviewed in viewer (e.g., KiCad Gerber viewer, Gerbv) before submissionCritical
- BOM cross-checked against schematic — all DNP/NF components flagged
- Pick-and-place (CPL) file generated and reviewed for correct centroid data
- Stack-up and impedance notes included in fab drawing or readme
Common DFM Pitfalls to Avoid
- Using 0201 components without matched thermal pad design — causes tombstoning
- Placing vias directly in IC thermal pads without VIPPO process — causes solder wicking
- Insufficient solder paste aperture reduction for large thermal pads — causes voiding
- Forgetting to add assembly fiducials on boards smaller than 50×50 mm
- Not reviewing Gerbers in a viewer before submission — catches layer assignment errors
Frequently Asked Questions
Design for Manufacturability (DFM) is a set of guidelines and checks that ensure a PCB can be reliably manufactured at the target volume and yield. DFM covers trace/space rules, component placement, pad geometry, solder mask, silkscreen, panelization, and test point placement.
DFM review should happen before Gerber generation, ideally during the layout phase. Fixing DFM issues during layout costs hours; fixing them after you've ordered PCBs costs weeks and hundreds to thousands of dollars in re-spins.
Common DFM failures include: insufficient paste relief on thermal pads (causing solder bridging), tombstoning of 0201 passives due to unequal pad heating, via-in-pad without fill/cap (causing solder wicking), insufficient courtyard clearance causing SMD-to-SMD conflicts, and missing test points on critical nets.
For standard PCB fabs (JLCPCB, PCBWay, standard tier), minimum trace/space is 5/5 mil. Premium fabs can go to 3/3 mil. For HDI microvia boards with fine-pitch BGAs, 2/2 mil or tighter may be required from specialist fabs.
Yes. We include DFM review as part of our PCB design service and offer standalone DFM audit services for designs developed elsewhere. Our review covers IPC-2221, IPC-7711/7721, and your target CM's specific design rules.
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Our PCB design engineers can audit your Gerbers and layout files for DFM issues before you commit to production.
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