Modified Semi Additive Process Yield Loss Recovery Contract Mechanics
Modified semi additive process contracts require clear yield baselines, defect attribution formulas, and flash-etch metrology to recover scrap costs cleanly.
Sap Photoresist
Imaging Medium
High resolution polymer films act as a mask for building conductors from the bottom up in specialized builds. The sap photoresist defines narrow channels where copper is added rather than removed. Using these materials allows for tighter spacing than conventional subtractive etching could ever reliably produce.
Chemical Resistance
Plating bath stability depends on the ability of the masking material to withstand high pH environments for long periods. During the use of sap photoresist, the thickness of the material must match the height of the copper goal exactly. Any softening of the resist walls during the electroplating stage causes dimensions to bloom and creates shorts between neighbor paths.
Technicians choose the exposure dose carefully to ensure the sidewalls stay perfectly vertical after development. This focus on vertical geometry ensures that signal integrity remains high for radio frequency circuits. If the film stays in the bath for more than four hours, it might leach organics that poison the copper solution.
Resolution Floor
Feature sizes can reach limits far below common industry standards when these films are correctly applied. The density limits of sap photoresist enable the manufacturing of high end smartphone components and advanced semiconductor packaging. Final yield depends on the absence of tiny particles that would block the growth of copper in the open channels.