During the backside grinding (BG) of wafer thinning process, by using grinding wheel, grind wafers close to the edge and leave the edge remain intact. This makes wafers with edges similar to the frame of a Taiko drum (and so the name of Taiko Grinding). This greatly removes warpage suffered by extremely thin wafers. The surfaces are then micro-etched with etching solution to remove the damage layer due to grinding and release stress.
Taiko Grinding Process
Tape wafers with tapes determined by wafer features and protection layers added by front end foundries after successful IQC; perform Pre-Grinding, Taiko Grinding, and Backside Wet Etching in sequence; perform non-contact thickness and Taiko ring width and thickness measurement before OQC.
The Superiority of iST
- Employ fully automatic DISCO equipment for Pre-grinding, Taiko Grinding, Taiko Ring Removal for precisely controlled grinding; single-piece etching machine available for rough or shining surface process for N- or P-type wafers as required by customers.
- Provide non-contact optical measurement for precision thickness, Taiko ring width and thickness which far outperforms the dial gauge widely adopted by the industry with and high precision measurement.
- A team of engineers with diversified experts including front end wafer foundry, wafer thinning and backend packaging house, knowledgeable and experienced in process integration and analysis in phases from front through middle to back and well-prepared to assist customers in accelerated development, troubleshooting, and mass production stabilization.
Post-grinding wafers: clearly visible grinding marks
Post-etching wafers: surface roughened
- Existing thickness options: 50~100um in mass production now, with thickness subject to customer requirements; 25~50um thickness in development, development and verification subject to customer requirements.
- Applicable to 8″/6″ P- or N-type wafers.