EPHEMERAL BONDING
Compositions suitable for temporarily bonding two surfaces, such as a wafer active side and a substrate, are disclosed. Methods of temporarily bonding two surfaces, such as the active side of a wafer and a substrate using the compositions disclosed herein are also provided.
1 . A method of releasably attaching a semiconductor wafer to a carrier substrate comprising:
(a) providing a semiconductor wafer having a front side and a back side;
(b) providing a carrier substrate having an attachment surface;
(c) disposing a temporary bonding composition comprising a curable adhesive material and a release additive between the front side of the semiconductor wafer and the attachment surface of the carrier substrate; and
(d) curing the adhesive material to provide a temporary bonding layer disposed between the front side of the semiconductor wafer and the attachment surface of the carrier substrate; wherein the temporary bonding layer adjacent to the attachment surface of the carrier substrate comprises a relatively lower amount of the release additive and the temporary bonding layer adjacent to the front side of the semiconductor wafer comprises a relatively higher amount of the release additive.
2 . The method of claim 1 wherein the curable adhesive material is chosen from polyarylene oligomers, cyclic-olefin oligomers, arylcyclobutene oligomers, and mixtures thereof.
3 . The method of claim 1 wherein the release additive is a polyether compound.
4 . The method of claim 3 wherein the release additive is chosen from polyalkylene oxide homopolymers and polyalkylene oxide copolymers.
5 . The method of claim 4 wherein the polyether compound comprises terminal groups chosen from hydroxy, alkoxy, aryloxy, and mixtures thereof.
6 . The method of claim 4 wherein the polyether compound is chosen from polyethylene glycol, polypropyleneglycol, poly(1,3-propanediol), polybutyleneglycol, poly(tetrahydrofuran), ethylene glycol-propylene glycol copolymers, and mixtures thereof.
7 . The method of claim 1 wherein the temporary bonding composition is cured by the use of heat, light, radiation, or a mixture thereof.
8 . The method of claim 1 further comprising the step of treating the attachment surface of the carrier substrate with an adhesion promoter prior to contact with the temporary bonding composition.
9 . The method of claim 1 further comprising the steps of: (e) performing an operation on the back side of the semiconductor wafer; and (f) separating the front side of the semiconductor wafer from the temporary bonding layer.
10 . The method of claim 1 wherein the temporary bonding composition further comprises an organic solvent.
11 . A structure comprising: a semiconductor wafer having a front side and a back side; a carrier substrate having an attachment surface; and a temporary bonding layer disposed between the front side of the semiconductor wafer and the attachment surface of the carrier substrate; wherein the temporary bonding layer comprises a cured adhesive material and a release additive; wherein the temporary bonding layer adjacent to the attachment surface of the carrier substrate comprises a relatively lower amount of the release additive and the temporary bonding layer adjacent to the front side of the semiconductor wafer comprises a relatively higher amount of the release additive.
12 . The structure of claim 11 further comprising an adhesion promoting layer disposed between the temporary bonding layer and the attachment surface of the carrier substrate.
13 . The structure of claim 11 wherein the temporary bonding layer and the front side of the semiconductor wafer have an adhesion energy of <3 J/m 2 .
14 . The structure of claim 11 wherein the temporary bonding layer and the attachment surface of the carrier substrate have an adhesion energy of >30 J/m 2 .
15 . The structure of claim 11 wherein the cured adhesive material is chosen from polyarylene polymers, cyclic-olefin polymers, arylcyclobutene polymers, and mixtures thereof.