Patent ID: 7972935
Filing Date: 2011-07-05
Classification: G11C,H01L

Abstract:
1. A method for manufacturing a semiconductor memory device comprising: irradiating a single crystal semiconductor substrate with hydrogen ions to form a single crystal semiconductor layer and a separation layer under the single crystal semiconductor layer, wherein the separation layer is formed at a certain depth from a surface of the single crystal semiconductor substrate; selectively etching the single crystal semiconductor layer and the separation layer to form a groove in the single crystal semiconductor substrate so as to divide the single crystal semiconductor layer into a first single crystal semiconductor layer and a second single crystal semiconductor layer; bonding a base substrate having an insulating surface and the first single crystal semiconductor layer with each other; separating the first single crystal semiconductor layer from the single crystal semiconductor substrate so as to leave the first single crystal semiconductor layer over the insulating surface of the base substrate; selectively etching the first single crystal semiconductor layer to divide into a third single crystal semiconductor layer and a fourth single crystal semiconductor layer; forming a first semiconductor memory comprising a first transistor by using the third single crystal semiconductor layer and a second semiconductor memory comprising a second transistor by using the fourth single crystal semiconductor layer.