Multi-objective optimization of laser scribing for the isolation process of solar cell wafers using grey relational analysis

A novel method is presented for optimizing laser scribing of solar cell wafers for the isolation process. Multiple performance characteristics are optimized using grey relational analysis (GRA). Laser scribing technology is a useful solution for solar cell isolation processes. Solar energy is available worldwide and useful to everybody. Most solar cell technology is currently based on silicon wafer technology. Two important targets for this solar cell industry are high effective rates of energy transfer and low manufacturing costs. The isolation process for solar cell silicon wafer processing using laser scribing technology needs a high quality process to obtain a good surface profie. This study uses a Q-switched diode-pumped solid-state laser (DPSSL) to perform the scribing. Results are characterized using three parameters, including two laser operation parameters (laser average power and Q-switching frequency), and one laser scanning parameter (laser scribing speed for manufacturing throughput). These parameters are optimized based on multiple performance characteristics. Some characteristics of the scribing isolation process using laser technology for solar cell wafers are verified. The characteristics of interest are the minimum width of the average scribing groove for edge isolation on wafer substrates and the maximum depth of the average groove. Nine experiments were conducted using GRA to optimize the values for laser scribing parameters in order to generate various quality characteristics. Analysis of the grey relational grade indicates parameter significance and the optimal parameter combination for the laser scribing process is identified. The measured analytical results using the optimal parameters confirm that laser scribing technology can be effectively applied to isolate the edge of solar cell wafers.