Temporary adhesion method, device wafer processing method, laminate for temporary adhesion, and laminate for device wafer processing

1 . A temporary adhesion method, the method comprising temporarily adhering a wafer to a support via a temporary adhesive layer, the wafer having a first main surface comprising a circuit and a second main surface to be processed, the second main surface being located on an opposite side to the first main surface,

wherein a temporary adhesion between the first main surface of the wafer and the support is performed via the temporary adhesive layer comprising a dry adhesive fiber structure having a plurality of pillar structures each having a main part and a tip having an upper end on top of the main part in which the width of the tip is enlarged toward the end directed upward,

wherein a ratio of cross sectional areas of the tip to the main part of each of the plurality of the pillar structures is 1:1 where the tip borders the main part and 2:1 at the top of the tip,

wherein each of the plurality of the pillar structures has a height of 1 μm to 1 mm, has a bottom surface having a diameter of 10 nm to 100 μm, and the tip of each of the plurality of the pillar structures has a diameter of 20 nm to 200 μm,

wherein the plurality of the pillar structures is formed at a density of 100/mm 2 or more and 5000/mm 2 or less,

wherein a structure in which the plurality of the pillar structures is formed with a silicone-modified polyimide is used as the dry adhesive fiber structure, and

wherein a structure with a capability of a repeated temporary adhesion is used as the temporary adhesive layer.

2 . A device wafer processing method, wherein

a temporary adhesion between the first main surface of the wafer and the support is performed by the temporary adhesion method according to claim 1 ; and

the second main surface of the wafer temporarily adhered is processed.

3 . The device wafer processing method according to claim 2 , wherein

a temporary adhesion with the temporary adhesive layer is released after processing the second main surface of the wafer; and

subsequently the temporary adhesive layer is reused for another temporary adhesion.

4 . The device wafer processing method according to claim 2 , wherein

a temporary adhesion with the temporary adhesive layer is released after processing the second main surface of the wafer; and

subsequently a substrate differing from the wafer is temporarily adhered to the support via the temporary adhesive layer.

5 . A laminate for temporary adhesion used for temporarily adhering a wafer to a support via a temporary adhesive layer, the laminate comprising:

the support; and

the temporary adhesive layer formed on the support,

wherein the temporary adhesive layer comprises a dry adhesive fiber structure having a plurality of pillar structures each having a main part and a tip having an upper end on top of the main part in which the width of the tip is enlarged toward the end directed upward,

wherein a ratio of cross sectional areas of the tip to the main part of each of the plurality of the pillar structures is 1:1 where the tip borders the main part and 2:1 at the top of the tip,

wherein each of the plurality of the pillar structures has a height of 1 μm to 1 mm, has a bottom surface having a diameter of 10 nm to 100 μm, and the tip of each of the plurality of the pillar structures has a diameter of 20 nm to 200 μm,

wherein the plurality of the pillar structures is formed at a density of 100/mm 2 or more and 5000/mm 2 or less,

wherein the plurality of the pillar structures is formed with a silicone-modified polyimide, and

wherein the temporary adhesive layer has a capability of a repeated temporary adhesion.

6 . The laminate for temporary adhesion according to claim 5 , further comprising a guard ring formed on the support and surrounding the dry adhesive fiber structure.

7 . A wafer processing laminate for device wafer processing, comprising:

the laminate for temporary adhesion according to claim 5 ; and

a wafer having a first main surface having a circuit and a second main surface to be processed, the second main surface being located on an opposite side to the first main surface, and the first main surface temporarily adhered to the support via the temporary adhesive layer on the support.