Method for Thinning Substrates

Abstract

According to various embodiments, a method includes: providing a substrate having a first side and a second side opposite the first side; forming a buried layer in and/or over the substrate by implanting a chemical element having a greater electronegativity than the substrate into the first side of the substrate by ion implantation; and thinning the substrate from the second side of the substrate, wherein the buried layer comprises a solid state compound having a greater resistance to the thinning than the substrate and wherein the thinning stops at the buried layer.

What is claimed is: 
     
         1 . A method, comprising:
 providing a substrate having a first side and a second side opposite the first side;   forming a buried layer in and/or over the substrate by implanting a chemical element having a greater electronegativity than the substrate into the first side of the substrate by ion implantation; and   thinning the substrate from the second side of the substrate, wherein the buried layer comprises a solid state compound having a greater resistance to the thinning than the substrate and wherein the thinning stops at the buried layer.   
     
     
         2 . The method of  claim 1 , wherein implanting the chemical element into the first side of the substrate comprises:
 implanting at least one of carbon ions and nitrogen ions into the first side of the substrate.   
     
     
         3 . The method of  claim 1 , wherein implanting the chemical element into the first side of the substrate comprises:
 exposing the first side of the substrate to an ion current including ions of the chemical element.   
     
     
         4 . The method of  claim 1 , wherein the buried layer is formed in the substrate and covered by a first portion of the substrate, wherein a thickness of the first portion of the substrate is in a range from about 50 nm to about 500 nm, and wherein a thickness of the buried layer is in a range from about 10 nm to about 100 nm. 
     
     
         5 . The method of  claim 4 , wherein the thickness of the first portion of the substrate is in a range from about 100 nm to about 250 nm, and wherein a thickness of the buried layer is in a range from about 20 nm to about 50 nm. 
     
     
         6 . The method of  claim 4 , further comprising:
 forming an epitaxial layer over the substrate; and   forming one or more electrical circuit elements in the epitaxial layer,   wherein a thickness of the epitaxial layer is in a range from about 1 micrometer to about 200 micrometers.   
     
     
         7 . The method of  claim 1 , wherein forming the buried layer comprises:
 forming a first epitaxial layer over the first side of the substrate; and   forming the buried layer in the first epitaxial layer, or between the substrate and the first epitaxial layer.   
     
     
         8 . The method of  claim 7 , wherein the buried layer is formed in the first epitaxial layer, the method further comprising:
 forming a second epitaxial layer over the first epitaxial layer; and   forming one or more electrical circuit elements in the second epitaxial layer,   wherein the second epitaxial layer is thicker than the first epitaxial layer.   
     
     
         9 . The method of  claim 8 , wherein a thickness of the second epitaxial layer is in a range from about 1 micrometer to about 200 micrometers. 
     
     
         10 . The method of  claim 1 , wherein implanting the chemical element into the first side of the substrate comprises:
 implanting ions of the chemical element into the first side of the substrate.   
     
     
         11 . The method of  claim 1 , wherein the substrate includes or is formed from silicon, and wherein the solid state compound comprises at least one of silicon nitride and silicon carbide. 
     
     
         12 . The method of  claim 1 , wherein forming the buried layer comprises:
 forming a first sublayer of the buried layer in the substrate by implanting first ions into the substrate; and   forming a second sublayer of the buried layer over the first sublayer and in the substrate by implanting second ions into the substrate.   
     
     
         13 . The method of  claim 12 , wherein the first ions include or are formed from ions of the chemical element. 
     
     
         14 . The method of  claim 13 , wherein the ions of the chemical element comprise at least one of carbon ions and nitrogen ions. 
     
     
         15 . The method of  claim 13 , wherein the second ions include or are formed from p-dopant ions. 
     
     
         16 . The method of  claim 12 , wherein the first ions are implanted into the substrate using a first implantation energy, wherein the second ions are implanted into the substrate using a second implantation energy, and wherein the first implantation energy is smaller than the second implantation energy. 
     
     
         17 . The method of  claim 16 , wherein a difference between the first implantation energy and the second implantation energy is selected so that an intermediate layer is formed between the first sublayer of the buried layer and the second sublayer of the buried layer. 
     
     
         18 . The method of  claim 1 , wherein forming the buried layer comprises:
 forming at least three sublayers of the buried layer in the substrate, including at least a first sublayer, a second sublayer and a third sublayer.   
     
     
         19 . The method of  claim 18 , wherein the second sublayer of the buried layer is disposed between the first sublayer of the buried layer and the third sublayer of the buried layer. 
     
     
         20 . The method of  claim 19 , wherein forming the at least three sublayers of the buried layer in the substrate comprises:
 prior to forming the second sublayer of the buried layer, implanting first ions of the chemical element into the substrate to form the first sublayer of the buried layer and the third sublayer of the buried layer;   forming an intermediate layer between the first sublayer of the buried layer and the third sublayer of the buried layer; and   implanting second ions into the intermediate layer to form the second sublayer of the buried layer.   
     
     
         21 . The method of  claim 1 , further comprising:
 tempering the substrate to homogenize a composition of the buried layer.   
     
     
         22 . The method of  claim 21 , wherein tempering the substrate comprises:
 heating a region including or formed from at least one of the buried layer and a cover layer formed over the buried layer above a. solid-liquid transition temperature or a glass transition temperature of the respective layer being heated.