US2021066081A1PendingUtilityA1

Methods and apparatuses related to shaping wafers fabricated by ion implantation

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Assignee: CREE INCPriority: Feb 7, 2019Filed: Nov 17, 2020Published: Mar 4, 2021
Est. expiryFeb 7, 2039(~12.5 yrs left)· nominal 20-yr term from priority
Inventors:Alexander SuvorovRobert Tyler LeonardEdward Robert Van Brunt
H10P 30/2042H10P 30/208H10P 30/204H10P 30/21H10P 30/2044H10D 30/028H10D 62/117H10D 62/8325H10D 62/156H01L 29/0657H01L 21/26506H01L 21/0415H01L 21/046H10P 30/218H10P 30/22
59
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Claims

Abstract

The wafer fabrication technique uses an ion implantation process on the back side of the wafer to control the shape of the wafer. At least one first dopant is implanted into a front side of a wafer to dope the wafer. At least one second dopant is implanted into a back side of the wafer in a dopant profile to create a back side structure, where the back side structure controls a shape of the wafer. A blank wafer is provided that has an undoped front side and a form shaping back side structure on the back side. A doped wafer is provided that has a dopant implanted on the front side and a form shaping back side structure on the back side that least partially offsets the strain in the wafer induced by the front side dopant.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
         1 . A blank wafer comprising:
 a front side and a back side;   a dopant profile implanted into the back side for controlling the shape of the wafer.   
     
     
         2 . The blank wafer according to  claim 1 , wherein the dopant profile is in at least one of a ring pattern, a ribbed pattern, a grid pattern, a ring and ribbed pattern and a pattern of discrete areas. 
     
     
         3 . The blank wafer according to  claim 1 , wherein the dopant profile comprises at least two dopants. 
     
     
         4 . The blank wafer according to  claim 1 , wherein the dopant profile creates a back side structure. 
     
     
         5 . The blank wafer according to  claim 4 , wherein the back side structure extends over less than the entire back side. 
     
     
         6 . The blank wafer according to  claim 4 , wherein the back side structure is in a masked pattern. 
     
     
         7 . The blank wafer according to  claim 1 , wherein the front side comprises an epitaxial layer. 
     
     
         8 . The blank wafer according to  claim 1 , wherein the blank wafer has a warped shape. 
     
     
         9 . The blank wafer according to  claim 1 , wherein the blank wafer has a non-planar shape. 
     
     
         10 . The blank wafer according to  claim 4 , wherein the back side structure is selected based on strains induced by a subsequent front side doping. 
     
     
         11 . A blank wafer comprising:
 a front side configured to support an active electrical device structure and a back side;   a dopant profile implanted into the back side such that the blank wafer has a desired intermediate shape.   
     
     
         12 . The blank wafer according to  claim 11 , wherein the desired intermediate shape is a warped shape. 
     
     
         13 . The blank wafer according to  claim 11 , wherein the desired intermediate shape is a shallow cup shape. 
     
     
         14 . The blank wafer according to  claim 11 , wherein the desired intermediate shape is a non-planar shape. 
     
     
         15 . The blank wafer according to  claim 11 , wherein the dopant profile implanted into the back side creates a back side structure. 
     
     
         16 . The blank wafer according to  claim 15 , wherein the back side structure is a universal back side structure that may be used over a range of front side doping implants to create the desired intermediate shape. 
     
     
         17 . The blank wafer according to  claim 11 , wherein the dopant profile is in at least one of a ring pattern, a ribbed pattern, a grid pattern and a ring, ribbed pattern and a pattern of discrete areas and inverses of such patterns. 
     
     
         18 . The blank wafer according to  claim 11 , wherein the dopant profile comprises a stacked structure. 
     
     
         19 . The blank wafer according to  claim 15 , wherein the back side structure induces un-offset strains in the blank wafer 
     
     
         20 . A method of making a blank wafer having a front side and a back side comprising:
 determining a back side structure to at least partially offset a strain in the wafer induced by a second dopant applied to the front side;   implanting a dopant profile into the back side of the wafer in an ion implantation process to create the back side structure

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