Improved bonding behavior by plasma coating for roughened surfaces

Direct bonding of glass and silicon wafers requires very low surface roughness. In many cases, substrates do not have a sufficient surface quality after polishing, or surface damages occurs from previous process steps. Experiments on roughened glass and silicon wafers suggest that silicon oxide layers with a high silanol concentration can be used to promote direct bonding for substrates having low surface quality. The layers were deposited from silane, SiH4, using atmospheric-pressure plasma-enhanced CVD.