Method of forming symmetric nozzles in an inkjet printhead

Abstract

A method of forming nozzles in an inkjet printhead including forming ink inlets in a first surface of a substrate, polishing a second surface of the substrate after the forming of the ink inlets, and forming ink outlets in the second surface of the substrate after the polishing of the second surface, the ink outlets communicating with the ink inlets.

1 . A method of forming nozzles in an inkjet printhead, comprising: 
 forming ink inlets in a first surface of a substrate;    polishing a second surface of the substrate after the forming of the ink inlets; and    forming ink outlets in the second surface of the substrate after the polishing of the second surface, the ink outlets communicating with the ink inlets.    
   
   
       2 . The method as claimed in  claim 1 , wherein each ink outlet is formed directly opposite a corresponding ink inlet.  
   
   
       3 . The method as claimed in  claim 2 , where the forming of the ink inlets includes removing a first portion of the substrate so as to partially penetrate the substrate; and 
 the forming of the ink outlets includes removing a second portion of the substrate opposite the first portion, so as to completely penetrate the substrate.    
   
   
       4 . The method as claimed in  claim 1 , wherein the forming of the ink inlets includes: 
 forming a first layer on the first surface of the substrate;    forming first apertures through the first layer by patterning the first layer, the first apertures exposing portions of the first surface of the substrate; and    etching the first surface of the substrate exposed through the first apertures.    
   
   
       5 . The method as claimed in  claim 4 , further including removing the first layer after the forming of the ink inlets and before the polishing of the second surface of the substrate.  
   
   
       6 . The method as claimed in  claim 4 , further including removing the first layer after the polishing of the second surface of the substrate.  
   
   
       7 . The method as claimed in  claim 4 , wherein the substrate is a silicon substrate, and 
 the first layer is a silicon oxide layer.    
   
   
       8 . The method as claimed in  claim 1 , wherein the ink inlets are formed to have an inverted pyramid shape.  
   
   
       9 . The method as claimed in  claim 1 , wherein the substrate is a single crystal substrate, and 
 the forming of the ink inlets includes an anisotropic etch.    
   
   
       10 . The method as claimed in  claim 9 , wherein the substrate is a single crystal silicon substrate.  
   
   
       11 . The method as claimed in  claim 9 , wherein the anisotropic etch is a wet etch using tetramethyl ammonium hydroxide (TMAH).  
   
   
       12 . The method as claimed in  claim 1 , wherein the polishing of the second surface of the substrate includes using chemical mechanical polishing (CMP).  
   
   
       13 . The method as claimed in  claim 1 , wherein the forming of the ink outlets includes: 
 forming a second layer on the second surface of the substrate;    forming second apertures through the second layer by patterning the second layer, the second apertures exposing portions of the second surface of the substrate;    forming the ink outlets by etching the second surface of the substrate exposed through the second apertures; and    removing the second layer.    
   
   
       14 . The method as claimed in  claim 13 , wherein the substrate is a silicon substrate, and 
 the second layer is a silicon oxide layer.    
   
   
       15 . The method as claimed in  claim 1 , wherein the forming of the ink outlets includes: 
 forming a second layer on the first and second surfaces of the substrate;    forming an aperture in the second layer on the second surface of the substrate; and    removing a portion of the second surface of the substrate so as to penetrate the substrate and the second layer on the first surface of the substrate.    
   
   
       16 . The method as claimed in  claim 1 , wherein the forming of the ink outlets includes a dry etch.  
   
   
       17 . The method as claimed in  claim 16 , wherein the dry etch is a reactive ion etch (RIE) using induced or inductively coupled plasma (ICP).