An effective monitored and improved method to control moisture for outgoing FOSB

Abstract

Quality control of outgoing wafer products is a critical item in the technical industry. An appropriate keeping environment (Humidity/Temperature…etc.) is necessary after the complex wafer manufacturing process to ensure the wafer quality. FOSB is an essential material during the wafer packing process and it can provide an isolated environment to protect outgoing wafers. But each FOSB has different properties, like different used times, clean recipe, moisture content…etc. During vacuum packaging, the humidity and pressure between the FOSB outside wall and packing bag reduces, and causes the moisture inside the FOSB to diffuse out. This then causes a humidity increase inside the FOSB, where wafers are placed (Experiment result humidity increase >5%). But the general method for detecting solid moisture content (like moisture analyser) is not suitable in FOSB, as it is such a big and unbreakable item. In this study, we understood the mechanism for inside humidity change after vacuum packing and found an effective monitored/improved method to control moisture for outgoing FOSB and ensure our packing processes are suitable, uniform, and the environmental status can be controlled precisely. Through this method we can enhance our quality control abilities and provide more assurance for both customers and producers.