Plasma etching method and apparatus, and method of manufacturing liquid ejection head

Abstract

The plasma etching method includes: an etching step of placing, on a stage in a chamber, a substrate in which a prescribed mask pattern is formed by a protective film on a surface of a material to be etched, generating a plasma in the chamber while supplying processing gas to the chamber, and etching a portion of the material corresponding to an opening portion in the mask pattern; a voltage measurement step of, during the etching in the etching step, measuring a voltage at the surface of the material on a side where the mask pattern is formed, through a conductive member that is placed in contact with the surface of the material on the side where the mask pattern is formed; and a control step of controlling an etching condition in the etching step in accordance with a measurement result obtained in the voltage measurement step.

1 . A plasma etching apparatus, comprising:
 a stage which holds a substrate having a prescribed mask pattern formed by a protective film on a surface of a material to be etched;   a chamber inside which the stage is arranged;   an evacuation device which evacuates gas from the chamber;   a processing gas supply device which supplies processing gas to the chamber;   a high-frequency power source which generates a plasma in the chamber;   a bias power source which applies a bias voltage to the stage;   a conductive member which contacts the surface of the material on a side where the mask pattern is formed, of the substrate held on the stage;   a voltage measurement device which measures a voltage at the surface of the material on the side where the mask pattern is formed, of the substrate held on the stage, through the conductive member; and   a control device which controls an etching condition in accordance with a measurement result obtained by the voltage measurement device.   
     
     
         2 . The apparatus as defined in  claim 1 , wherein the control device stores the measurement result obtained in an etching step of the substrate as a target value, and when processing a subsequent substrate, adjusts the etching condition for the subsequent substrate so as to obtain the measurement result same with the target value. 
     
     
         3 . The apparatus as defined in  claim 1 , wherein:
 the stage has a clamp member by which the substrate is held on the stage; and   the conductive member is arranged in the clamp member.   
     
     
         4 . The apparatus as defined in  claim 1 , wherein the measurement result obtained by the voltage measurement device includes a self-bias voltage at the surface of the material. 
     
     
         5 . The apparatus as defined in  claim 1 , wherein the measurement result obtained by the voltage measurement device includes a peak-to-peak voltage at the surface of the material. 
     
     
         6 . The apparatus as defined in  claim 1 , wherein the etching condition controlled by the control device includes output of the high-frequency power source. 
     
     
         7 . The apparatus as defined in  claim 1 , wherein the etching condition controlled by the control device includes output of the bias power source. 
     
     
         8 . The apparatus as defined in  claim 1 , wherein the etching condition controlled by the control device includes a flow volume of the processing gas. 
     
     
         9 . The apparatus as defined in  claim 1 , wherein the etching condition controlled by the control device includes a pressure in the chamber.