Patent ID: 6315850
Filing Date: 2001-11-13
Classification: B29C,B32B,G02B,Y10T

Abstract:
A process for producing a stress-free bond at ambient temperature and pressure between two layers of dissimilar material comprising the steps of:(a) providing a first layer with a coefficient of thermal expansion which is smaller than a coefficient of thermal expansion of a second layer, with a thickness which is smaller than a thickness of the second layer, and with a thermal conductivity which is larger than a thermal conductivity of the second layer;(b) providing a bonding layer, having a thickness substantially less than the thickness of the first layer, with a softening temperature above the ambient temperature, at the ambient pressure;(c) arranging the first layer and the second layer, with the bonding layer in between the first layer and the second layer;(d) placing a heat sink in thermal contact with a surface of the second layer opposite to a surface which is in contact with the bonding layer;(e) placing a pulsed heat source in thermal contact with a surface of the first layer which is opposite to a surface which is in contact with the bonding layer;(f) applying a compressional force between the pulsed heat source and the heat sink so as to compress the first layer and the second layer so that the bonding layer flows when the bonding layer reaches its softening or melting temperature; and(g) applying a heat pulse of an intensity and duration sufficient to melt or soften the bonding layer to raise an interfacial surface temperature of the second layer above a melting or softening temperature of the bonding layer without substantially heating a remainder of the second layer.