Wafer applied thermally conductive interposer
View Patent ↗A thermally conductive film is attached to an integrated circuit (IC) wafer through a number of steps. Initially, a thermally conductive film is positioned on a first side of a block. Next, an IC wafer that includes a plurality of chips is positioned with its non-active side in contact with the film. Then, a first surface of an elastomer pad is positioned in contact with an active side of the wafer. Next, a predetermined pressure is applied between a second side of the block that is opposite the first side and a second surface of the elastomer pad that is opposite the first surface. Finally, the film, the block, the wafer and the elastomer pad are heated to a predetermined temperature for a predetermined time while a predetermined pressure is applied to bond the film to the wafer without bonding the film to the block.
1. A method of attaching a thermally conductive film to an integrated circuit (IC) chip, comprising the steps of:
positioning a thermally conductive film on a first side of a block;
positioning an IC wafer on the film, wherein a non-active side of the wafer is in contact with the film, and wherein the IC wafer includes a plurality of chips;
positioning a first surface of an elastomer pad in contact with an active side of the wafer, wherein the active side of the wafer is opposite the non-active side of the wafer;
applying a predetermined pressure between a second side of the block that is opposite the first side and second surface of the elastomer pad that is opposite the first surface; and
heating the film, the block, the wafer and the elastomer pad to a predetermined temperature for a predetermined time while the predetermined pressure is applied to bond the film to the wafer, wherein the film does not bond to the block.
2. The method of claim 1 , wherein the film is a graphite filled thermoplastic epoxy material.
3. The method of claim 1 , wherein the coefficient of thermal expansion (CTE) of the film is about 29 ppm/° C.
4. The method of claim 1 wherein the coefficient of thermal expansion (CTE) of the film is about 29 ppm/° C.
5. The method of claim 1 , wherein the glass transition temperature of the film is about 200 degrees Celsius.
6. The method of claim 1 , wherein the glass transition temperature of the film is abut 200 degrees Celsius.
7. The method of claim 1 , wherein the heat and the pressure are applied for between about forty-five to sixty minutes, and wherein the pressure is about 25 pounds per square inch (PSI) and the temperature is about 130 degrees Celsius.
8. The method of claim 1 , wherein the block is made of TEFLON.
9. The method of claim 1 , further including the steps of:
removing the applied heat and pressure from the wafer;
applying an adhesive tape to the wafer;
dicing individual ones of the chips from the wafer;
electrically attaching at least one of the diced chips to a substrate;
placing the chip and its associated film against a heat sink backplate; and
applying a bonding temperature to the chip to bond the film with the heat sink backplate.
10. The method of claim 9 , wherein the chips are in one of a flip chip package and a chip scale package (CSP).
11. A method of attaching a thermally conductive film to an integrated circuit (IC) chip, comprising the steps of:
positioning a thermally conductive film on a first side of a TEFLON block, wherein the film is a graphite filled thermoplastic epoxy material;
positioning an IC wafer on the film, wherein a non-active side of the wafer is in contact with the film, and wherein the IC wafer includes a plurality of chips;
positioning a first surface of an elastomer pad in contact with an active side of the wafer, wherein the active side of the wafer is opposite the non-active side of the wafer;
applying a predetermined pressure between a second side of the block that is opposite the first side and second surface of the elastomer pad that is opposite the first surface; and
beating the film, the block, the wafer and the elastomer pad to a predetermined temperature for a predetermined time while the predetermined pressure is applied to bond the film to the water, wherein the film does not bond to the block.
12. The method of claim 11 , wherein the coefficient of thermal expansion (CTE) of the film is about 29 ppm/° C.
13. The method of claim 11 , wherein the glass transition temperature of the film is about 200 degrees Celsius.
14. The method of claim 11 , wherein the heat and the pressure are applied for between about forty-five to sixty minutes, and wherein the pressure is about 25 pounds pet square inch (PSI) and the temperature is about 130 degrees Celsius.
15. The method of claim 11 , further including the steps of:
removing the applied heat and pressure from the water;
applying an adhesive tape to the water;
dicing individual ones of the chips from the wafer;
electrically attaching at least one of the diced chips to a substrate;
placing the chip and its associated film against a heat sink backplate; and
applying a bonding temperature to the chip to bond the film with the heat sink backplate.
16. The method of claim 15 , wherein the chips are in one of a flip chip package and a chip scale package (CSP).
17. A method of attaching a thermally conductive film to an integrated circuit (IC) chip, comprising the steps of:
positioning a thermally conductive film on a first side of a TEFLON block, wherein the film is a graphite filled thermoplastic epoxy material;
positioning an IC wafer on the film, wherein a non-active side of the wafer is in contact with the film, and wherein the IC wafer includes a plurality of chips;
positioning a first surface of an elastomer pad in contact with an active side of the wafer, wherein the active side of the wafer is opposite the non-active side of the wafer;
applying a predetermined pressure between a second side of the block that is opposite the first side and second surface of the elastomer pad that is opposite the first surface; and
heating the film, the block, the wafer and the elastomer pad to a predetermined temperature for a predetermined time while the predetermined pressure is applied to bond the film to the wafer, wherein, the coefficient of thermal expansion (CTE) of the film is about 29 ppm/° C., and wherein the glass transition temperature of the film is about 200 degrees Celsius and the film does not bond to the block.
18. The method of claim 17 , wherein the heat and the pressure are applied for between about forty-five to sixty minutes, and
wherein the pressure is about 25 pounds per square inch (PSI) and the temperature is about 130 degrees Celsius.
19. The method of claim 17 , further including the steps of:
removing the applied heat and pressure from the wafer;
applying an adhesive tape to the wafer;
dicing individual ones of the chips from the wafer;
electrically attaching at least one of the diced chips to a substrate;
placing the chip and its associated film against a heat sink backplate; and
applying a bonding temperature to the chip to bond the film with the heat sink backplate.
20. The method of claim 19 , wherein the chips are in one of a flip chip package and a chip scale package (CSP).