Patterned Sapphire Substrate Manufacturing Method

Abstract

A patterned sapphire substrate manufacturing method uses two-section dip etching procedure to improve the lateral etching rate at each etching position, so as to produce a concave-convex pattern composed of a plurality of triangular pyramid structures protruded from a surface onto an upper surface of a sapphire substrate, such that less planar area of the sapphire substrate surface will remain, and a mixed solution of sulfuric acid and phosphoric acid is used in a first dip etching step, and pure phosphoric acid or a mixed solution of sulfuric acid and phosphoric acid is used in a second dip etching step for etching the sapphire substrate to control the inclination of each triangular pyramid structure precisely, and providing a better light extraction rate for later manufactured light emitting diodes.

1 . A patterned sapphire substrate manufacturing method, and the sapphire substrate having an upper surface with a crystal orientation (0001), and the method comprising the steps of:
 (a) selectively forming an etching barrier onto the upper surface of the sapphire substrate, such that a portion of the upper surface is exposed;   (b) using a first etching solution to etch the exposed portion of the upper surface of the sapphire substrate, such that a plurality of triangular pyramid frustum structures are formed onto the upper surface of the sapphire substrate, wherein each triangular pyramid structure of the plurality of triangular pyramid frustum structures has a first crystal face with an orientation (1012), a second crystal face with an orientation (0112), and a third crystal face with an orientation (1102), and the first etching solution is a mixed solution of sulfuric acid and phosphoric acid used for performing a first etch, and the ratio of the sulfuric acid and the phosphoric acid is 3:1;   (c) using the first etching solution to etch the exposed portion on the upper surface of the sapphire substrate, such that the plurality of triangular pyramid frustum structures are formed into the whole triangular pyramid structures, and the second etching solution is pure phosphoric acid.   
     
     
         2 . The patterned sapphire substrate manufacturing method of  claim 1 , wherein the first etch is preferably performed at a temperature of 270° C. 
     
     
         3 . The patterned sapphire substrate manufacturing method of  claim 1 , wherein the second etch is preferably performed at a temperature of 270° C. 
     
     
         4 . The patterned sapphire substrate manufacturing method of  claim 1 , wherein the etching barrier is formed by silicon oxide. 
     
     
         5 . The patterned sapphire substrate manufacturing method of  claim 1 , wherein the etching barrier is formed onto the upper surface of the sapphire substrate by a chemical vapor deposition process or a sputtering process. 
     
     
         6 . A patterned sapphire substrate manufacturing method, and the sapphire substrate having an upper surface with a crystal orientation (0001), and the method comprising the steps of:
 (a) selectively forming an etching barrier onto the upper surface of the sapphire substrate, such that a portion of the upper surface is exposed;   (b) using a first etching solution to etch the exposed portion of the upper surface of the sapphire substrate, such that a plurality of triangular pyramid frustum structures are formed onto the upper surface of the sapphire substrate, wherein each triangular pyramid structure of the plurality of triangular pyramid frustum structures has a first crystal face with an orientation (1012), a second crystal face with an orientation (0112), and a third crystal face with an orientation (1102), and the first etching solution is a mixed solution of sulfuric acid and phosphoric acid used for performing a first etch, and the ratio of the sulfuric acid and the phosphoric acid is 5:1;   (c) using the first etching solution to etch the exposed portion on the upper surface of the sapphire substrate, such that the plurality of triangular pyramid frustum structures are formed into the whole triangular pyramid structures, and the second etching solution is a mixed solution of sulfuric acid and phosphoric acid, and the ratio of the sulfuric acid and the phosphoric acid is 5:1.   
     
     
         7 . The patterned sapphire substrate manufacturing method of  claim 6 , wherein the etching barrier is made of silicon oxide. 
     
     
         8 . The patterned sapphire substrate manufacturing method of  claim 6 , wherein the etching barrier is formed onto the upper surface of the sapphire substrate by a chemical vapor deposition process or a sputtering process.