The development of new laser debonding techniques involving Borofloat, a borosilicate glass from the Schott technology group has boosted the drive towards flatter and thinner silicon wafers. Borofloat is well recognised as a standard material for Micro-ElectroMechanical Systems (MEMS) processes such as anodic bonding, mainly because of its characteristics of very accurate flatness and predictable thermal performance. Anodic bonding is widely used to combine silicon wafers with borosilicate glass to cap MEMS, other electronic and optical parts or to seal micro fluidic devices. A perfect match between the two substrates is critical to ensure good bonding behaviour. The breakthrough from Schott has created new forms of de-bonding. Laser de-bonding through a glass carrier wafer made of Borofloat glass is possible because of deep UV light transmission at the relevant laser wavelength range. It is this factor that facilitates the production of larger and thinner silicon wafers in what is a perdurable production process. As well as today’s designs of smaller and flatter products, there is also the demand for higher yield rates which makes larger and thinner wafers necessary.
