Method of etching backside ink supply channels for an inkjet printhead

Abstract

A method of etching backside ink supply channels for an inkjet printhead. The method includes the steps of: (a) attaching a frontside of the printhead to a handle wafer; (b) etching the backside of the printhead using an anisotropic DRIE process to form a plurality of ink supply channels, the DRIE process including alternating etching and passivation steps, the passivation steps depositing a polymeric coating on sidewalls of the ink supply channels; and (c) removing the polymeric coating by etching the backside of the printhead in a biased plasma etching chamber using an O 2 plasma. The chamber temperature is in the range of 90 to 180° C.

1 . A method of etching backside ink supply channels for an inkjet printhead, said method comprising the steps of:
 (a) attaching a frontside of said printhead to a handle wafer;   (b) etching the backside of said printhead using an anisotropic DRIE process to form a plurality of ink supply channels, said DRIE process including alternating etching and passivation steps, said passivation steps depositing a polymeric coating on sidewalls of said ink supply channels;   (c) removing said polymeric coating by etching the backside of said printhead in a biased plasma etching chamber using an O 2  plasma,   
       wherein said chamber temperature is in the range of 90 to 180° C. 
     
     
         2 . The method of  claim 1 , wherein said etching chamber is an inductively coupled plasma (ICP) etching chamber. 
     
     
         3 . The method of  claim 2 , wherein an ICP power is in the range of 2000 to 3000 W. 
     
     
         4 . The method of  claim 1 , wherein said frontside of said printhead is attached to a platen, and a biasing platen power is in the range of 10 to 100 W. 
     
     
         5 . The method of  claim 1 , wherein said chamber temperature is in the range of 120 to 150° C. 
     
     
         6 . The method of  claim 1 , wherein a chamber pressure is in the range of 30 to 120 mTorr. 
     
     
         7 . The method of  claim 1 , wherein a chamber pressure is in the range of 60 to 100 mTorr. 
     
     
         8 . The method of  claim 1 , where said platen has a temperature in the range of 5 to 20° C. 
     
     
         9 . The method of  claim 8 , wherein said platen is cooled using backside helium cooling. 
     
     
         10 . The method of  claim 1 , wherein an oxygen flow rate to said chamber is in the range of 20 to 200 sccm. 
     
     
         11 . The method of  claim 1 , wherein an etching time is in the range of 40 to 80 minutes. 
     
     
         12 . The method of  claim 1 , wherein said polymeric coating is a hydrophobic fluoropolymer. 
     
     
         13 . The method of  claim 1 , wherein said ink supply channel has a width in the range of 20 to 120 microns 
     
     
         14 . The method of  claim 1 , wherein said ink supply channel has a depth of at least 100 microns. 
     
     
         15 . The method of  claim 1 , wherein the frontside of said printhead is attached to the handle wafer using adhesive tape.