Solid-state image sensor and manufacturing method of the sensor

Abstract

A single crystal silicon layer is formed on a principal surface of a first wafer by epitaxial growth. A silicon oxide layer is formed on the single crystal silicon layer. Next, a defect layer is formed inside the single crystal silicon layer by ion implantation, and then, the second wafer is bonded to the silicon oxide layer on the first wafer. After that, an SOI wafer including the silicon oxide layer formed on the second wafer and the single crystal silicon layer formed on the silicon oxide layer is formed by separating the first wafer including the single crystal silicon layer from the second wafer including the single crystal silicon layer in the defect layer. Then, a photodiode is formed in the single crystal silicon layer. An interconnect layer is formed on a surface of the single crystal silicon layer which is opposite to the silicon oxide layer.

1 . A manufacturing method of a solid-state image sensor comprising:
 forming a single crystal silicon layer on a principal surface of a first wafer by epitaxial growth;   forming a silicon oxide layer on the single crystal silicon layer;   forming a defect layer inside the single crystal silicon layer by ion implantation;   bonding the second wafer to the silicon oxide layer on the first wafer;   forming an SOI wafer including the silicon oxide layer formed on the second wafer and the single crystal silicon layer formed on the silicon oxide layer by separating the first wafer including the single crystal silicon layer from the second wafer including the single crystal silicon layer in the defect layer;   forming a photodiode in the single crystal silicon layer; and   forming an interconnect layer including a photodiode charge read-out structure on a surface of the single crystal silicon layer which is opposite to the silicon oxide layer.   
     
     
         2 . The method of  claim 1 , further comprising
 after forming the interconnect layer, selectively etching part of or the entire second wafer with respect to the silicon oxide layer, wherein   in forming the photodiode, the light-receiving section of the photodiode is formed to face the silicon oxide layer.   
     
     
         3 . A manufacturing method of a solid-state image sensor comprising:
 forming a first single crystal silicon layer on a principal surface of a first wafer by epitaxial growth;   forming a silicon oxide layer on the first single crystal silicon layer;   forming a defect layer inside the first single crystal silicon layer by ion implantation;   bonding the second wafer to the silicon oxide layer on the first wafer;   forming an SOI wafer including the silicon oxide layer formed on the second wafer and the first single crystal silicon layer formed on the silicon oxide layer by separating the first wafer including the first single crystal silicon layer from the second wafer including the first single crystal silicon layer in the defect layer;   forming a second single crystal silicon layer on the first single crystal silicon layer by epitaxial growth;   forming a photodiode in the first single crystal silicon layer or the second single crystal silicon layer; and   forming an interconnect layer including a photodiode charge read-out structure on a surface of the second single crystal silicon layer which is opposite to the first single crystal silicon layer.   
     
     
         4 . The method of  claim 3 , further comprising
 after forming the interconnect layer, selectively etching part of or the entire second wafer with respect to the silicon oxide layer, wherein   in forming the photodiode, the light-receiving section of the photodiode is formed to face the silicon oxide layer.   
     
     
         5 . A manufacturing method of a solid-state image sensor comprising:
 forming a first single crystal silicon layer having impurity concentration of 1×10 17  cm −3  or more on a principal surface of a first wafer by epitaxial growth;   forming a silicon oxide layer on the first single crystal silicon layer;   forming a defect layer inside the first single crystal silicon layer by ion implantation;   bonding the second wafer to the silicon oxide layer on the first wafer;   forming an SOI wafer including the silicon oxide layer formed on the second wafer and the first single crystal silicon layer formed on the silicon oxide layer by separating the first wafer including the first single crystal silicon layer from the second wafer including the first single crystal silicon layer in the defect layer;   forming a second single crystal silicon layer having lower impurity concentration than the first single crystal silicon layer on the first single crystal silicon layer by epitaxial growth;   forming a photodiode in the second single crystal silicon layer so that a light-receiving section faces the silicon oxide layer;   forming an interconnect layer including a photodiode charge read-out structure on a surface of the second single crystal silicon layer which is opposite to the first single crystal silicon layer; and   selectively etching part of or the entire second wafer with respect to the silicon oxide layer.   
     
     
         6 . The method of  claim 5 , wherein
 the first single crystal silicon layer is of a first conductivity type,   the second single crystal silicon layer is of a second conductivity type, and   the photodiode is of the second conductivity type.   
     
     
         7 . The method of  claim 5 , wherein
 the first single crystal silicon layer is of a first conductivity type,   the second single crystal silicon layer is of a second conductivity type,   the forming of the photodiode includes forming a well of the first conductivity type in the second single crystal silicon layer, and   the photodiode is of the second conductivity type, and is formed in the well.   
     
     
         8 . A solid-state image sensor comprising:
 a plate-like single crystal silicon layer formed by epitaxial growth, and including a first surface and a second surface facing the first surface;   an interconnect layer provided on the first surface of the single crystal silicon layer and including a photodiode charge read-out structure; and   a plurality of photodiodes formed in the single crystal silicon layer so that light-receiving sections face the second surface.   
     
     
         9 . The solid-state image sensor of  claim 8 , further comprising:
 an insulating film provided on the second surface of the single crystal silicon layer; and   color filters provided on the insulating film to correspond to the photodiodes.   
     
     
         10 . The solid-state image sensor of  claim 8 , further comprising
 on-chip microlenses provided on the second surface of the single crystal silicon layer to correspond to the photodiodes.   
     
     
         11 . The solid-state image sensor of  claim 8 , further comprising
 an insulating film provided on the second surface of the single crystal silicon layer;   color filters provided on the insulating film; and   on-chip microlenses provided on the color filters to correspond to the photodiodes.