Six Mil Traces Change the Process

The target combined 6 mil PCB features with 0.35 mm BGA geometry. At that scale, a low-cost commercial board house sells extraordinary process control for roughly two dollars per square inch. The value lies in registration, clean holes, isolated pads, plated connections, and consistent yield.

The home experiments reached about 0.5 mm as a repeatable multilayer feature size. Below that scale, glue or etchant moved into the electrical geometry, holes lost conduction, neighboring pads bridged, and layer alignment consumed the design margin.

Additive Layers Opened Another Route

A 10 mil target and Scotch tape changed the process from copper removal to additive construction. A laser engraver cut a low-adhesion mask. Conductive paste filled the openings under a squeegee. Removing the mask lifted excess particles away while leaving the intended circuit.

Repeated masks could build multiple layers without ordinary drilling and etching. Conical breakouts that widened from 10 mil to 12 mil across successive layers created a path toward larger BGA and QFN connections in conductive ink, paper, and tape.

The Maker Fab Starts With Process Windows

The sequence matters: seven failed material systems revealed the variables that control the result, then the additive mask converted one of those variables into a repeatable step. The next build can optimize adhesion, paste flow, registration, breakout geometry, drying, and electrical yield.

The Missing Maker Fab extends this same ambition from PCB interconnects into accessible semiconductor fabrication. Bring a process, measurement, or material that can move the path forward.