Inputs
- Finished trace width
- Copper thickness
- Etch factor
- Process bias
FPC / PCB Engineering Calculator
Etching Compensation Calculator
Estimate artwork width from finished trace width, copper thickness and etch factor.
How to use the Etching Compensation Calculator
Etching compensation converts a target finished trace width into an artwork width. Thicker copper and lower etch factor increase side etch.
Artwork width estimate
Formula: Artwork width = finished width + 2 x side etch + process bias
- Finished width: target trace width after etching.
- Side etch: lateral copper loss per side.
- Process bias: extra compensation based on factory experience.
Formula Basis
- Formula basis: etch-factor geometry using copper thickness and lateral side etch.
- Engineering note: production artwork compensation should be tuned from measured factory etching data.
Example
For 0.10 mm finished trace, 35 um copper and etch factor 3, side etch is about 11.7 um per side.
Outputs
- Recommended artwork width
- Estimated side etch per side
Engineering Notes
- Etch factor depends on equipment, chemistry, copper thickness and pattern density.
- Fine-line FPC requires close alignment between design rules and real etching capability.
- Use production measurement feedback to replace the generic process bias.
Validation Checks
- Minimum finished trace width
- Copper thickness selection
- Artwork compensation
- Copper balance
Related Manufacturing Process
- Etching - Etch factor, undercut, finished width, copper balance
Related Calculators
- Via Aspect Ratio Calculator - Check finished hole aspect ratio, drill allowance and annular ring.
- Copper Plating Time Calculator - Estimate copper plating current, time and amp-hour loading.
- PCB Panelization / Panel Utilization Calculator - Calculate PCB panelization count, rotation option and material utilization.
- Coverlay Opening Calculator - Estimate coverlay opening size and bridge width from pad size, registration and adhesive allowance.
FAQ
Is etch factor fixed?
No. It changes with process chemistry, conveyor speed, copper thickness, pattern density and equipment condition.
Why include process bias?
Factories often apply empirical compensation from historical measurement data. This is where your own formula can become much stronger.