Method of backside grinding a bumped wafer
A method for backside grinding a bumped wafer is disclosed. A wafer has a plurality of bumps formed on the active surface thereof. Prior to grinding the back surface of the wafer, a hot-melt adhesive layer is formed on the active surface of the wafer so as to be adhered to the active surface and cover the bumps. Also a grinding film is attached to the hot-melt adhesive layer. After grinding the back surface of the wafer, the grinding film is removed but the hot-melt adhesive layer is remained on the wafer for the following wafer-dicing step.
1. A method of backside grinding a bumped wafer, the method comprising:
providing a bumped wafer, the bumped wafer having an active surface with a plurality of bumps formed thereon and a back surface;
forming a hot-melt adhesive layer on the active surface and the bumps, wherein the hot-melt adhesive partially covers the bumps;
forming a first film on the hot-melt adhesive layer;
forming a second film on the back surface;
removing the first film;
singulating the wafer into a plurality of chips, the chips attached on the second film; and
removing the hot-melt adhesive layer so as to have the bumps exposed.
2. The method of claim 1 , wherein the step of forming the hot-melt adhesive layer on the active surface and the bumps is performed at a temperature higher than about 80° C.
3. The method of claim 1 , wherein the step of forming the hot-melt adhesive layer on the active surface and the bumps is performed at a temperature equal to about 80° C.
4. The method of claim 1 , wherein said the area of each bump covered by the hot-melt adhesive layer is at least larger than sixty percents of the area of said each bump.
5. The method of claim 1 , wherein the hot-melt adhesive layer comprises a transparent adhesive.
6. The method of claim 1 , wherein the hot-melt adhesive layer comprises an elastic adhesive.
7. The method of claim 1 , wherein the active surface further has an electronic device formed thereon.
8. The method of claim 1 , wherein the electronic device comprises a passive component.
9. The method of claim 1 , further forming a dam at a periphery of the active surface before the step of forming the hot-melt adhesive layer on the active surface.
10. The method of claim 1 , wherein the step of removing the first film is performed at a temperature less than a temperature at which the step of forming a hot-melt adhesive layer on the active surface and the bumps is performed.
11. The method of claim 1 , wherein the step of removing the first film is performed at a temperature equal to a temperature at which the step of forming a hot-melt adhesive layer on the active surface and the bumps is performed.
12. The method of claim 1 , further comprising a step grinding the back surface before the step of forming a second film on the back surface.
13. A method of backside grinding a bumped wafer, the method comprising:
providing a bumped wafer, the bumped wafer having an active surface with a device formed thereon and a back surface;
forming a hot-melt adhesive on the active surface and the device, wherein the hot-melt adhesive layer partially covers the device;
forming a first film on the hot-melt adhesive;
forming a second film on the back surface;
removing the first film; and
removing the hot-melt adhesive layer so as to have the device exposed.
14. The method of claim 13 , wherein the step of forming the hot-melt adhesive layer on the active surface is performed at a temperature higher than 80° C.
15. The method of claim 13 , further comprising a step grinding the back surface before the step of forming a second film on the back surface.
16. The method of claim 13 , wherein the device is entirely covered by the hot-melt adhesive layer.
17. The method of claim 13 , wherein the hot-melt adhesive layer comprises a transparent adhesive layer.
18. The method of claim 13 , wherein the hot-melt adhesive comprises an elastic adhesive layer.
19. The method of claim 13 , wherein the device comprises a surface mount device.
20. The method of claim 13 , wherein the device comprises a solder ball.
21. The method of claim 13 , wherein the device comprises a metal post.
22. The method of claim 13 , wherein the device comprises a wire.
23. The method of claim 13 , further forming a dam at a periphery of the active surface before the step of forming the hot-melt adhesive layer on the active surface.
24. The method of claim 13 , wherein the step of removing the first film is performed at a temperature less than a temperature at which the step of forming a hot-melt adhesive layer on the active surface and the device is performed.
25. The method of claim 13 , wherein the step of removing the first film is performed at a temperature equal to a temperature at which the step of forming a hot-melt adhesive layer on the active surface and the device is performed.