A Process-Capability Roadmap for Achieving Cpk Above 1.67 Across Twenty Critical Parameters in High-Volume Solar Cell Manufacturing

Abstract

Achieving Process Capability Index (Cpk) values above 1.67 across the full critical-parameter set is widely regarded as the operational target separating mature from immature solar cell manufacturing. This study presents a structured roadmap progressing from Cpk-naive baseline through six maturity stages, illustrated against a representative set of twenty critical parameters spanning incoming wafer quality, diffusion uniformity, antireflection coating thickness, metallization linewidth, firing-profile peak temperature, and end-of-line efficiency. Each stage defines its data-infrastructure prerequisites, measurement-system-analysis requirements, and the engineering-organization practices needed to achieve and sustain capability gains. The roadmap is offered as a practitioner-grade reference complementing the theoretical literature on process capability.