Patent ID: 8247309
Filing Date: 2012-08-21
Classification: H01L

Abstract:
1. A method of reducing surface roughness and improving thickness uniformity in a transfer layer that is transferred from a donor substrate of semiconductor material onto a receiving substrate, which method comprises: disposing the donor substrate on a circular gasket held by a platen so as to define an enclosed recess between a backside of the substrate and the platen, the circular gasket forming a partial seal between the substrate and the platen; implanting ions by bombarding a front face of a donor substrate with an ion beam to form, at a predetermined depth in the donor substrate, a layer of weakness that includes microcavities or platelets and that defines the transfer layer between layer of weakness and the front face; during the implanting, diffusing a cooling gas into the recess and across the backside of the donor substrate, the cooling gas escaping the recess through the partial seal; bonding the front face of the donor substrate to a face of the receiving substrate; and detaching the transfer layer by splitting the microcavities or platelets at the layer of weakness in the donor substrate in order to transfer the layer to the receiving substrate; wherein the gasket enables the cooling gas to better maintain the donor substrate at a mean temperature in the range 20° C. to 150° C. with a maximum temperature variation of less than 30° C. during the implanting to reduce surface roughness and improve thickness uniformity of the transfer layer.