Ephemeral bonding
Compositions containing an adhesive material and a release additive are suitable for temporarily bonding two surfaces, such as a wafer active side and a substrate. These compositions are useful in the manufacture of electronic devices where a component, such as an active wafer, is temporarily bonded to a substrate, followed by further processing of the active wafer.
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;
(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; wherein the release additive is a polyether compound; and wherein the release additive is free of silicon;
(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.
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 chosen from polyalkylene oxide homopolymers and polyalkylene oxide copolymers.
4. The method of claim 1 wherein the polyether compound comprises terminal groups chosen from hydroxy, alkoxy, aryloxy, and mixtures thereof.
5. The method of claim 1 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.
6. The method of claim 1 wherein the temporary bonding composition is cured by the use of heat, light, radiation, or a mixture thereof.
7. 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.
8. The method of claim 1 wherein the temporary bonding composition further comprises an organic solvent.
9. The method of claim 1 wherein the release additive is non-curable under conditions used to cure the adhesive material.
10. The method of claim 1 wherein the release additive phase separates from the adhesive material during curing of the adhesive material.