In semiconductor manufacturing, precision is key. As small consumer electronics flood the market, demand for thin wafers that can hold up to heat specs shows no sign of slowing down. One research group addressed some of the problems with backgrinding silicon wafers, and sought to address the issues by testing new measuring technology.
Issues with Backgrinding
- Backgrinding produces scratches on the surface of silicon wafers during the thinning process.
- These scratches create a rough surface and weaken the material. The pattern of scratches created by backgrinding also affects die fracture strength.
- Measuring wafers precisely for quality control is difficult because current techniques only measure a small area of the wafer instead of the entire surface.
- Current techniques take 20-30s per measurement, and require additional equipment to reduce noise.
The purpose of the study was to test a new measuring method in order to save time and materials, while also producing more meaningful measurements for quality control purposes.
Proposed Scattered Light Technology
The authors propose using a scattered light sensor to quickly and correctly measure silicon wafers. This technique has already been proven in other manufacturing processes. Testing the scattered light sensor indeed resulted in much faster, more thorough readings. The authors believe that being able to easily analyze the entire surface area of wafers subjected to different grinding techniques will inform process improvement.
Read the paper and view diagrams on Solid State Technology: Fast and precise surface measurement of back-grinding silicon wafers