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.
Micro-Etch Rate
Kinetic Property
Chemical speed determines the amount of copper mass removed per unit of immersion time. A micro-etch rate measures how efficiently an acid solution creates the tiny textures needed for copper layers to stick. Controlling this process ensures that metal surfaces are clean enough for subsequent plating without being too thin to function.
Bath Balance
Copper concentrations and temperature directly modify how fast the solution eats into the solid metal. Every micro-etch rate is calibrated by dipping test coupons for specific intervals and weighing them before and after. Standard operations target between zero point five and one point five microns of removal depth.
If the chemistry becomes too saturated with dissolved copper, the speed drops and results in smooth, poorly adhering traces. Technicians add fresh oxidizers frequently to keep the removal speed within the desired operational window. Measuring this every shift prevents common errors like delamination during assembly.
Surface Anchor
High speeds might create overly deep pits that trap moisture and cause outgassing. Within typical production, the micro-etch rate balances clean geometry with the need for a high surface area for dry film adhesion. Failure to maintain consistency here results in entire panels of circuits peeling apart during high heat cycles.