Patent EP-2224476-A1 (EP)
Inventor: FOURNEL FRANCK
IPC: H01L21/762
Filed: 2010-02-22
Abstract: The process comprises preparing a first substrate (3A) of which a monocrystalline layer made of a first material is present, separating the first substrate into two parts to release two surfaces of two superficial portions (11, 12) of which the crystalline axis are in perfect coincidence during separation, preparing a second temporary substrate (3B) by forming two superficial portions on the surface of the first substrate and a mixed layer made of a second material on first areas (13) and second adjacent areas (14) made of a third material in amorphous form. The process comprises preparing a first substrate (3A) of which a monocrystalline layer made of a first material is present, separating the first substrate into two parts to release two surfaces of two superficial portions (11, 12) of which the crystalline axis are in perfect coincidence during separation, preparing a second temporary substrate (3B) by forming two superficial portions on the surface of the first substrate and a mixed layer made of a second material on first areas (13) and second adjacent areas (14) made of a third material in amorphous form, pasting the surface of the second superficial portions with the temporary substrate by molecular pasting on the amorphous areas so that the surface has the same crystallographic orientation portion, and applying a heat treatment to the mixed layer to cause the solid phase recrystallization of an amorphous area following the common crystallographic orientation of two superficial portions. The second areas have a difference composition and/or crystallographic form with respect to the first areas and form a part of the free surface of the temporary substrate. Retrieval marks are developed in the first substrate on both sides of the weakened area during the fracture depending on a given related configuration with respect to the fracture layer. The second superficial portion is pasted to the temporary substrate after laying the second portion so that the retrieval marks are in that given relative configuration with respect to the mixed layer. One of the superficial portions is partly removed after pasting of the second superficial portion towards the mixed layer. The removal is carried out by separating between the superficial portion and recrystallized areas of the mixed layer. One of sides to be pasted is roughened by molecular pasting and separating at the interface. The second superficial portion for degrading the mechanical strength is present near the interface. An embrittlement is applied to the second superficial portion by ion implantation to a given depth. The heat treatment for recrystallization is adapted for recrystallizing the amorphous areas and, after separation, a second heat treatment is applied for completing the recrystallization of the amorphous areas. The constituent material of second areas has a composition identical to that of the first areas. The constituent material of second areas and the amorphous areas have a common element. The mixed layer is made of single material having predefined crystallographic orientation areas. The second areas are obtained by amorphization of a monocrystalline layer initially having the crystallographic orientation of the first areas, and formed by digging a monocrystalline layer initially having the crystallographic orientation of first areas and by depositing the second material in amorphous form in the dug cavities. The amorphous material is deposited to form a layer covering the first areas.