Lead-Free PCB Guide
Coordinate laminate, surface finish, components and soldering requirements—and keep material declarations separate from process qualification.
Lead-free is a coordinated build requirement.
A lead-free finish is one input. The complete project also needs compatible materials, components, soldering conditions and documented requirements.
Use separate specifications for the bare board, component terminations and assembly solder. For example, AIM identifies SAC305 as a tin/silver/copper lead-free alloy; that alloy designation does not define every other material in a finished product.
Four parts of the same manufacturing decision.
Laminate and board construction
Review the intended thermal exposure against the specified material and finished construction. High-performance laminates can be designed for lead-free assembly, but a Tg number alone does not qualify the board.
Surface finish
Identify the actual finish process and the expected assembly sequence. Lead-free HASL is one option; chemical finishes also need compatibility and handling review.
Component terminations and packages
Confirm part-level material information, package limits and moisture-sensitive handling. Use the specific manufacturer’s package information rather than a blanket assumption for all components.
Solder alloy and flux system
Specify the alloy and paste or flux product, including storage and processing instructions. SAC305 is one lead-free choice; lower-temperature lead-free alloy systems also exist.
A melting range is not a reflow recipe.
SAC305: a useful example, not a universal setting
AIM lists SAC305 as 96.5% tin, 3.0% silver and 0.5% copper, with a melting range of 217–220 °C. These alloy properties do not mean that every solder joint should peak at that temperature, or that every component can tolerate the same profile.
Package-specific limits differ. AMD, for example, publishes separate peak body-temperature requirements for different packages and processing circumstances. A component qualification limit is not an instruction to run an entire PCB at that limit.
What belongs in the qualification record.
The approved process window
Identify the paste/flux guidance, package constraints, board limits and the complete sequence of reflow, wave/selective soldering and rework.
Representative measurements
Record thermocouple locations, assembly revision and loading conditions. Evaluate both difficult-to-heat joints and temperature-sensitive components.
Controlled production changes
Record the released process, inspection criteria and permitted changes. Reassess the qualification when materials, thermal mass or the assembly sequence change.
Keep the declaration tied to its scope.
RoHS concerns more than lead
The European Commission identifies ten restricted substances under the RoHS framework. The Commission’s RoHS guidance describes restrictions at the homogeneous-material level. A lead-free alloy statement therefore does not answer every RoHS question.
Check the applicable product scope, market and any exemption against the current official rules. Retain the relevant supplier declarations and the evidence required by your compliance plan.
Build a useful evidence package
Ask for declarations tied to part numbers and revisions, the approved material list, relevant lot traceability and any agreed analytical evidence. State exactly what the supplier is declaring.
Keep process-control records separate from material-content evidence. A successful solder joint does not prove a substance declaration, and a declaration does not prove the reliability of a soldering profile.
Questions before
you release the design.
Use these answers to clarify the specification, then resolve project-specific requirements with your manufacturing and assembly teams.
Is lead-free the same as RoHS-compliant?
No. Lead-free addresses lead within a defined scope. RoHS concerns additional restricted substances and includes scope, concentration and exemption questions. Evaluate the complete product and applicable obligations.
Is a halogen-free laminate automatically lead-free?
The terms describe different requirements. A material supplier may declare both, but one label is not a substitute for the other declaration. Specify the exact grade and required evidence.
Should every lead-free board use a 260 °C peak?
No. The alloy, paste, package and board constraints must be reconciled in a qualified profile. Package limits are product-specific; do not treat a widely repeated peak temperature as a universal recipe.
Does a higher-Tg laminate guarantee reflow reliability?
No. Review the actual construction and complete thermal history, and define the required qualification. A single transition-temperature value is not a finished-board reliability guarantee.
Does completing the checklist establish compliance?
No. It records review tasks. The evidence, technical acceptance and applicable conformity assessment remain separate responsibilities.
Review lead-free readiness before release.
Bring these points to your project discussion with GlobalWellPCB. Mark the items you have reviewed and keep the unresolved questions with the design files.
Review items are not technical approval.
Local checklist only. Nothing is uploaded or saved to a server.
Related engineering resources
Technical references
- [1] AIM Solder — SAC305 lead-free alloy
- [2] European Commission — RoHS Directive, scope and exemptions
- [3] Panasonic — Halogen-free MEGTRON 6
- [4] Isola — FR408HR laminate and prepreg
- [5] Würth Elektronik — Technical Delivery Specification for PCBs (PDF)
- [6] MKS Atotech — Final finishing technologies
- [7] Texas Instruments — Package information and MSL lookup
- [8] AIM Solder — Sn42/Bi58 low-temperature alloy
- [9] AMD — Package-specific peak reflow temperatures
- [10] Coilcraft — Soldering Coilcraft Components
- [11] Analog Devices — Moisture-sensitivity-level explanation
- [12] European Commission — RoHS 2 FAQ, homogeneous materials and substance restrictions (PDF)
Use these references to compare materials and technical requirements. Confirm the exact grade, construction and applicable documents for your board before ordering.