# PCBA Design for Manufacturing (DFM) Review Checklist > Source: https://netray.co/tools/pcba-dfm-design-for-manufacturing-review-checklist > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: Free Tools ## Short answer Checklist to review a PCB design for assembly before release: panel, fiducials, pads, stencil, test and documentation. ## Category electronics ## Industry Electronics Manufacturing ## Audience - PCB designer - NPI engineer - EMS process engineer ## Tool **Kind:** checklist **Scoring Note:** Every critical item left open is a likely cause of a delay or yield problem. Resolve all critical items before releasing the design to the EMS or the line. **Groups:** #### Board and panel **Items:** **Text:** Board outline, thickness and layer stackup are defined on the fabrication drawing **Critical:** true Panel or array drawing shows rails, tooling holes and the break method (V score or tab routed) **Text:** Tab locations keep stress away from ceramic capacitors and BGAs **Critical:** true Board edge keep out for components matches the conveyor and depaneling method Board bow and twist limits are stated for the finished assembly **Text:** Surface finish and its standard are specified, for example ENIG or OSP **Critical:** true #### Fiducials and tooling **Items:** **Text:** Global fiducials are present on each side that carries parts **Critical:** true Local fiducials are present for fine pitch parts and large BGAs Fiducials have clear copper free area and no solder mask conflict Tooling holes are non plated and placed to the machine requirement Fiducials are asymmetric enough to avoid loading the panel rotated #### Pads, spacing and stencil **Items:** **Text:** Land patterns follow the IPC-7351 style and the manufacturer datasheet **Critical:** true Component to component spacing allows placement, inspection and rework Thermal pads on QFN and similar parts have a defined paste aperture pattern Solder mask dams exist between fine pitch pads where the fabricator can hold them **Text:** Chip components have symmetrical pads and thermal relief to avoid tombstoning **Critical:** true Via in pad is filled and capped or tented as required **Text:** Stencil thickness and aperture reductions have been reviewed for the finest pitch part **Critical:** true Tall components are not placed next to small fine pitch parts that need printing and rework space #### Components and BOM **Items:** **Text:** Every BOM line has a manufacturer and manufacturer part number **Critical:** true **Text:** Reference designators in the BOM match the CAD and centroid file **Critical:** true Polarity and pin 1 marks are visible on the silkscreen after assembly Moisture sensitive parts are identified with their MSL End of life and long lead time parts are flagged and alternates approved Do not populate parts are marked consistently in BOM and assembly drawing Through hole parts have a selective, wave or hand solder method defined #### Test and inspection **Items:** Test points are accessible for in circuit or flying probe test with sufficient spacing Programming and debug headers are accessible and described BGA and other hidden joints have an inspection method agreed (X-ray) **Text:** IPC class (2 or 3) is stated on the drawing **Critical:** true Conformal coating or potting areas and keep out zones are defined #### Documentation and release **Items:** **Text:** Gerber or ODB++ package, drill, BOM, centroid and assembly drawing are all on the same revision **Critical:** true Special process notes (press fit, underfill, glue) are on the drawing Labeling, serial number and traceability requirements are stated Packaging and ESD requirements are described Open DFM questions are logged and signed off before release ## Content **Intro:** A design that passes electrical checks can still be hard or expensive to assemble. This checklist helps the design team and the assembler review a PCBA before release so problems with panels, fiducials, pads, stencils and documentation are found early. **Sections:** #### How to use the checklist **Body:** Run the review with the layout engineer and a process engineer present. Go through the groups in order, tick items that are confirmed and note actions for anything open. Critical items are those that commonly stop a build or cause yield loss. Export the completed list as evidence with the release package and attach the action log to the engineering change record. #### What DFM covers **Body:** DFM covers three layers: the board (panel, finish, outline), the assembly (pads, spacing, fiducials, stencil) and the information package (BOM, centroid, drawings). IPC-7351 gives guidance on land patterns, IPC-2221 on generic design, and IPC-A-610 and J-STD-001 define acceptance and soldering requirements for the product class you build. **Bullets:** - Early review is far cheaper than a board respin - Ask the assembler for their DFM rules before layout - Use one revision for every file in the package #### Worked example **Body:** A review finds that a QFN thermal pad has a single large paste aperture. The process engineer proposes a window pane pattern to reduce voiding and floating. The layout engineer updates the stencil file, and the decision is recorded as a closed critical item with the new stencil revision. #### Common mistakes **Body:** Teams often hold the DFM review after the PCB fabrication order, when changes mean new boards. Another mistake is sending files from different revisions, which causes quantity and designator mismatches. A third is missing manufacturer part numbers, which forces the buyer to guess and risks the wrong part. **Cta:** Netray can help link DFM findings and engineering changes to your ERP item and BOM records so the release is traceable. **Faq:** #### When should a DFM review be done? **Answer:** Before PCB fabrication is ordered, ideally at layout review, and again before the first build. Early reviews cost little. Late changes can mean new boards, a new stencil and schedule delays. #### Who should attend? **Answer:** The layout engineer, a manufacturing or process engineer, a test engineer and a buyer. A quality engineer helps with the IPC class and inspection plan. #### What are fiducials for? **Answer:** Fiducials are copper marks that vision systems on the printer and placement machine use to find the true board position. They compensate for panel and board distortion. #### Is this checklist enough for IPC class 3? **Answer:** It is a general review aid. Class 3 products add stricter workmanship, documentation and inspection requirements, so check the customer contract and IPC standards for your specific program. ## Search terms dfm checklist pcb assembly, pcba design for manufacturing checklist, pcb dfm review template, smt design rules checklist, pcb fiducial requirements, design for assembly checklist electronics, npi dfm review, pcb panel design checklist --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json