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.
Step-down Yield Curve
Statistical Model
Predictive data sets illustrate the predictable decline in usable units as boards move through various production stages. A step-down yield curve maps each manufacturing station where errors might happen, from drill to test. It allows production managers to overstuff initial orders so they end up with the correct quantity at the finish.
Volume Forecast
Mathematical estimates show that an eight layer board will lose more units during image and etch than a simpler double sided sheet. Every step-down yield curve starts at one hundred percent and drops as panels fail inspection at automated stations. If the visual pattern of the drop is too sharp at the plating stage, it signals a systemic problem with the chemical bath.
High reliability products often have a shallower start but finish lower because final acceptance criteria are more demanding. Designers use this curve to judge the commercial viability of high density interconnect techniques. If early prototypes show too steep a fall, the price for high volume runs must rise to compensate for the waste.
Operational Baseline
Typical curves become standard for the factory over several years of running similar jobs. Consistent reference to the step-down yield curve prevents the sales team from promising delivery dates that the shop floor cannot physically meet. The model only stays accurate if data from every shift is correctly reported.