Process optimization of Plated Through-hole (PTH) process using Evolutionary Operation (EVOP)

Interconnections between the various signal and voltage layers of a printed circuit board are typically accomplished using plated through holes. This technology involves a series of process steps including: mechanical drilling, hole cleaning, catalyzing for autocatalytic deposition of copper, and finally copper plating. This paper proposes an evolutionary operation approach for improving the quality and yield of the plated through-hole process. The technique includes two major steps: process characterization and optimization. Process characterization is used to identify the parameters that significantly influence the process responses, such as yield. Following the process characterization, an evolutionary optimization technique is used for the process optimization, which is suitable for implementation in a full-scale manufacturing process. In particular, this paper addresses a variable size sequential simplex method to rapidly optimize system parameters involving several continuous factors. This method mainly includes the identification of the vertices of the initial simplex and a step-by-step sequence of evolutionary adjacent movements of simplexes towards the optimal region.