A comparative study of the bonding energy in adhesive wafer bonding

• Published in: Journal of micromechanics and microengineering Vol. 23; no. 8; pp. 85019 - 7
• Main Authors: Forsberg, F, Saharil, F, Haraldsson, T, Roxhed, N, Stemme, G, van der Wijngaart, W, Niklaus, F
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.08.2013; Institute of Physics
• Subjects: Adhesive bonding; Applied sciences; BCB; Benzocyclobutene; Bond energy; Bonding; Delaminating; Dies; Electronics; Energy use; Exact sciences and technology; heterogeneous integration; Level; Microelectronic fabrication (materials and surfaces technology); Microfluidic Devices; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silicon; SU-8; wafer bonding; Wafers; Wafer bonding; Microelectronic fabrication; Engraving; Adhesive strength; Epoxy resin; Blistering; Polymer; Silicon; Delamination
• ISSN: 0960-1317; 1361-6439; 1361-6439
• DOI: 10.1088/0960-1317/23/8/085019

Adhesion energies are determined for three different polymers currently used in adhesive wafer bonding of silicon wafers. The adhesion energies of the polymer off-stoichiometry thiol-ene-epoxy OSTE+ and the nano-imprint resist mr-I 9150XP are determined. The results are compared to the adhesion energies of wafers bonded with benzocyclobutene, both with and without adhesion promoter. The adhesion energies of the bonds are studied by blister tests, consisting of delaminating silicon lids bonded to silicon dies with etched circular cavities, using compressed nitrogen gas. The critical pressure needed for delamination is converted into an estimate of the bond adhesion energy. The fabrication of test dies and the evaluation method are described in detail. The mean bond energies of OSTE+ were determined to be 2.1 and 20 J m−2 depending on the choice of the epoxy used. A mean bond energy of 1.5 J m−2 was measured for mr-I 9150XP.