WAFER MOUNTING

1,267,320. Seaming. INTERNATIONAL BUSINESS MACHINES CORP. 24 Nov., 1970 [30 Dec., 1969], No. 55762/70. Heading B5K. [Also in Divisions B3 and H1] A semi-conductor wafer 25 is bonded to a surface 17 of a support 10, which surface is flat when cool but convex as shown when hot, by heating the support 10 to the bonding temperature, spreading a bonding agent over the surface 17, placing the wafer 25 into contact with the highest point of the surface 17, e.g. using a rubber-coated vacuum tool, and maintaining the wafer 25 in contact with the surface 17 while the support 10 cools down and resumes its flat shape. The bonding agent is thus forced outwards from the highest point of the surface 17 as the latter cools, and voids in the bonding layer are avoided. After mounting in this way the wafer 25 may be cut into chips for device manufacture. The support 10 is preferably made of a phenolic resin, the bonding agent being glycol phthalate and being preheated and applied in a metered amount to the surface 17. A concave cooled forming tool is used to shape the bonding agent over the surface 17 prior to positioning of the wafer 25.