Highly conductive composition for wafer coating
View Patent ↗A conductive composition for coating a semiconductor wafer comprises conductive filler that has an average particle size of less than 2 microns and a maximum particle size of less than 10 microns, a first resin that has a softening point between 80-260° C., solvent, curing agent, and a second resin, wherein at room temperature the first resin is substantially soluble in the solvent.
1. A semiconductor wafer having a front side that is active and a back side that is opposed to the front side that is inactive wherein the back side of the semiconductor wafer is coated with a conductive composition comprising:
a) 66 to 80 wt % conductive filler that has an average particle size of less than 2 microns and a maximum particle size of less than 5 microns,
b) 5 to 25 wt % first resin that has a softening point between 80-260° C.,
c) 5 to 25 wt % solvent,
d) 0 to 5 wt % curing agent, and
e) 0 to 20 wt % second resin,
wherein at room temperature the first resin is substantially soluble in the solvent.
2. The semiconductor wafer of claim 1 wherein the conductive filler is silver and the silver has a surface area of at least 1 m 2 /g.
3. The semiconductor wafer of claim 1 wherein the first resin is a bismaleimide.
4. The semiconductor wafer of claim 1 wherein the solvent is tetramethyl urea.
5. The semiconductor wafer of claim 1 wherein the second resin is selected from the group consisting of bismaleimide, epoxy, and acrylate.
6. The semiconductor wafer of claim 1 wherein the conductive filler is silver, the first resin is a bismaleimide, and the solvent is tetramethyl urea, wherein the sliver has a surface area of at least 1 m 2 /g.