Coating adhesives onto dicing before grinding and micro-fabricated wafers
View Patent ↗A method for preparing a semiconductor wafer into individual semiconductor dies uses both a dicing before grinding step and/or via hole micro-fabrication step, and an adhesive coating step.
1. A method for preparing a semiconductor wafer into individual semiconductor circuits, the wafer having a plurality of circuits on the top side of the wafer, the method comprising the steps of:
(1) applying a tape onto the back side of the wafer;
(2) forming dicing grooves or via holes into the top side of the wafer between adjacent circuits to a final target depth, or slightly deeper, for the wafer;
(3) removing the tape from the back side of the wafer and applying a tape onto the top side of the wafer;
(4) thinning the wafer by removing material from the back side of the wafer
(5) applying an adhesive coating to the back side of the circuits;
(6) B-stage curing the adhesive either thermally or photochemically;
(7) removing the tape from the top side of the wafer and applying a tape onto the adhesive coating.
2. The method according to claim 1 in which the adhesive coating is applied by spin coating, spray coating, ink jetting, or needle dispensing.
3. The method according to claim 1 in which the adhesive coating is substantially absent from the dicing streets and via holes.
4. The method according to claim 1 in which the adhesive coating is applied with a thickness within the range of 5 to 100 micrometers.
5. The method according to claim 1 in which the adhesive applied forms a meniscus that has a decrease in adhesive thickness near the die edge.