Liquid composition, method of producing silicon substrate, and method of producing liquid discharge head substrate

Abstract

A liquid composition used to carry out crystal anisotropic etching of a silicon substrate provided with an etching mask formed of a silicon oxide film with the silicon oxide film used as a mask includes cesium hydroxide, an alkaline organic compound, and water.

1 . A liquid composition used to carry out crystal anisotropic etching of a silicon substrate provided with an etching mask formed of a silicon oxide film with the silicon oxide film used as a mask, the liquid composition comprising:
 cesium hydroxide;   an alkaline organic compound; and   water.   
     
     
         2 . The liquid composition according to  claim 1 , wherein the alkaline organic compound includes tetramethylammonium hydroxide. 
     
     
         3 . The liquid composition according to  claim 1 , wherein a ratio by weight of the cesium hydroxide to the weight of the liquid composition is 1% by weight to 40% by weight inclusive. 
     
     
         4 . The liquid composition according to  claim 2 , wherein a ratio by weight of the tetramethylammonium hydroxide to the weight of the liquid composition is 5% by weight to 25% by weight inclusive. 
     
     
         5 . A method of producing a silicon substrate, the method comprising:
 preparing a silicon substrate on which a silicon oxide film formed with an opening is formed on at least one surface of the substrate; and   etching the substrate from the opening by using a liquid composition containing cesium hydroxide, an alkaline organic compound, and water as an etching solution and using the oxide film as a mask to form a through-port penetrating through the substrate.   
     
     
         6 . The method according to  claim 5 , wherein the alkaline organic compound includes tetramethylammonium hydroxide. 
     
     
         7 . A method of producing a liquid discharge head substrate including a silicon substrate provided with an energy generation element generating energy used to discharge ink above a first surface of the silicon substrate, the liquid discharge head substrate being provided with a supply port penetrating through the liquid discharge head substrate to supply a liquid to the energy generation element, the method comprising:
 preparing a silicon substrate including the energy generation element disposed above the first surface and a silicon oxide film with an opening on at least a second surface which is a back surface of the silicon substrate;   etching the silicon substrate from the opening by using a liquid composition containing cesium hydroxide, an alkaline organic compound, and water as an etching solution and using the oxide film as a mask to form a through-port penetrating through the silicon substrate; and   forming the supply port by using the through-port.   
     
     
         8 . The method according to  claim 7 , wherein the alkaline organic compound includes tetramethylammonium hydroxide.