Si wafer Edge grinding/Down sizing
From wafers with large diameter (150-300 mm), simply polished, SOI (Silicon On Insulator) or with devices on to smaller diameters (2", 3" or 100 mm).
Sil'tronix Silicon Technologies supplies down sizing solution according the following operations :
- Spin coating of a classical photoresist resin on one or both sides as protection of the sensible surfaces already performed
- Laser cutting of the wafer with potential one, two or more wafers designed with standard flats following the orientation of the initial wafer.
- Edge rounding at the precise final diameter +/- 0.02 mm if needed.
- Removing of the protected resin
- Cleaning and packaging the wafers in compatible boxes under vacuum in cleanroom.
The residual rings (after laser cutting) could be diced in squares for additional test pieces.
Silicon is very hard, but brittle material. The sharp edge of sawn wafers fractures readily, producing unacceptable edge chips and particles. This edge is ground with a diamond disk to remove the damage and to eliminate periferical stress. By edge grinding, the final diameter of the wafer is adjusted. During this process, we adjust also the flat (major and minor) according the SEMI standard.
Specific profile :
On customer’s request, we can also provide non standard wafers. We can adjust the diameter of the wafer to a specific value (e.g ; 60mm diameter). We can also modify the length or the position of the flat (e.g. JEIDA flat, for a 6 inches wafer, the lenght of the flat is 45.7mm). For silicon parts with a thickness above 1mm, we can also make a beveled edge (e.g., edge with 45° angle)