In the second post of this series, I described how a chance encounter between two old college classmates forever changed SunPower’s fortunes, and that semiconductor and solar cell production had little in common. This post describes how Cypress process controls and production innovations were implemented to accelerate learning and achieve low-cost, high-volume production of high-performance solar cells.
The Cypress Years, Part Two: Processes, Autoline and Accelerated Learning
Chuck Stone was engineering manager at the Cypress facility in Texas where SunPower production development was initially conducted. He was charged with instilling Cypress business processes into SunPower. Three key processes were critical in the low-cost, high-volume production of solar cells: equipment procurement reviews (EPR), statistical process control (SPC) and process control reviews (PCR).
Chuck recalls that because semiconductor equipment was too expensive and no high-volume solar cell production equipment existed, “We effectively created the first modern solar-cell supply chain.” Cypress specified the equipment it needed to vendors that were eager to get a foothold in this new, promising industry. EPR was employed to ensure that the novel equipment consistently met the exacting specifications required for low-cost, high-volume production.
SPC was employed to identify and control key variables for improved product quality, cost and cycle-time. PCR enabled the product development team to characterize, qualify and verify initial process designs and revisions. According to Chuck, “PCR is critical because if you do it right, the solution you define in development is the final production solution.”
Another key aspect of solar cell production was the Autoline. This transformed the multi-stage semiconductor production process into a single, continuous process for solar cell production—from raw silicon wafer to finished product. Not only did this lower cost, but it reduced cycle time from weeks to days. According to T.J. Rodgers, “The Autoline completely changes the discipline and culture of manufacturing.”
Chuck Stone recalls that the greatest benefit of the Autoline process was from accelerated learning. “With semiconductor manufacturing, we conducted critical process reviews, such as yield, once a month. With solar cell production, we did it weekly.” The increased frequency of review and learning allowed SunPower to improve processes, reduce cost and increase production more quickly. In 2004, Chuck led a team that began high-volume production at the SunPower Fab 1 facility in the Philippines at an annual output rate of 110 MW. Three years later SunPower launched Fab 2 at an annual output rate of 480 MW.