Equipment productivity improvement via inline qualification implementation

Abstract

This paper discusses inline etch equipment qualification implementation at the 200 mm Infineon Technologies Richmond fab. Traditional etch equipment qualification requires offline etching of test blanket (or pattern) wafers of known thickness during a defined period. The process etch rate can be calculated using known film thickness and etch time. Data is obtained using an SPC system, which is then used to qualify the tool set. As a part of process control and data acquisition, time of etch is currently being monitored for automatic endpoint steps. The etch time is collected by an equipment integration software package, which communicates directly with the tool and records readings from sensors, step times, and other process conditions. The etch time is then combined with SPC gathered pre etch film thickness to determine an inline, on product, process etch rate. This gives the ability to monitor a chamber's performance without a costly break in the production for purposes of running a test wafer. This also allows instant detection of an out of control (OOC) process and prevents a significant scrap event.