Plasma processing apparatus

Abstract

According to one embodiment, a plasma processing apparatus that includes a process target holding portion and a plasma generating unit in a chamber, and processes a process target by using generated plasma is provided. An yttrium oxide film is formed on an inner wall of the chamber and a surface of a structural member in the chamber on a generation region side of the plasma. The yttrium oxide film includes yttrium oxide particles, has a film thickness of 10 μm or more and 200 μm or less, has a film density of 90% or more, and is such that yttrium oxide particles, which are present in a unit area 20 μm×20 μm and whose grain boundary is confirmable, are 0 to 80% in area ratio.

1 . A plasma processing apparatus that includes a process target holding portion that holds a process target in a chamber and a plasma generating unit that turns gas introduced into the chamber into plasma, and processes the process target by using generated plasma, wherein
 an yttrium oxide film is formed on an inner wall of the chamber and a surface of a structural member in the chamber on a generation region side of plasma generated in the plasma generating unit, and   the yttrium oxide film includes yttrium oxide particles, has a film thickness of 10 μm or more and 200 μm or less, has a film density of 90% or more, and is such that yttrium oxide particles, which are present in a unit area 20 μm×20 μm and whose grain boundary is confirmable, are 0 to 80% in area ratio and yttrium oxide particles, whose grain boundary is not confirmable, is 20 to 100% in area ratio.   
     
     
         2 . The plasma processing apparatus according to  claim 1 , wherein the plasma generating unit is a plate-like gas supplying member that is arranged to face the process target holding portion, supplies the gas to a side of the process target holding portion via a gas ejection port, and functions as an electrode that turns the gas into plasma. 
     
     
         3 . The plasma processing apparatus according to  claim 2 , wherein
 the gas supplying member includes a gas ejection port that includes a first hole having a first diameter and a second hole, which is connected to one end portion of the first hole, whose opening diameter increases from the end portion to be a second diameter larger than the first diameter, and which is provided on one main surface side of the gas supplying member, and   the yttrium oxide film is provided on a surface forming the second hole and the one main surface of the gas supplying member.   
     
     
         4 . The plasma processing apparatus according to  claim 1 , further comprising a tubular inner wall protective member provided to be fitted in an inner wall of the chamber exposed to the plasma generation region, wherein
 the yttrium oxide film is formed on a surface of the inner wall protective member on the plasma generation region side.   
     
     
         5 . The plasma processing apparatus according to  claim 4 , wherein
 the inner wall protective member includes a shutter that openably covers an opening provided to move the process target between an inside and an outside of the chamber, and   the yttrium oxide film is formed also on a surface of the shutter on the plasma generation region side.   
     
     
         6 . The plasma processing apparatus according to  claim 1 , wherein
 the process target holding portion includes
 a support member that holds the process target and functions as an electrode that turns the gas into plasma, and 
 an insulator ring that is provided to cover a side surface of the support member and is formed of a dielectric material, and 
   the yttrium oxide film is provided on an upper surface and an outer peripheral portion of the insulator ring to be the plasma generation region side.   
     
     
         7 . The plasma processing apparatus according to  claim 6 , wherein
 the process target holding portion includes a focus ring that is arranged around the process target placed on the support member and is formed of a conductive material, and   the yttrium oxide film is provided on a surface of the focus ring on the plasma generation region side.   
     
     
         8 . The plasma processing apparatus according to  claim 1 , further comprising a baffle plate that connects an outer periphery of the process target holding portion and a sidewall of the chamber, and includes a gas exhaust hole from which gas on the plasma generation region side is exhausted, wherein
 the yttrium oxide film is provided on a surface of the baffle plate on the plasma generation region side.   
     
     
         9 . The plasma processing apparatus according to  claim 1 , wherein the yttrium oxide particles are yttrium oxide particles whose purity is 99.9% or more. 
     
     
         10 . The plasma processing apparatus according to  claim 1 , wherein the yttrium oxide film has a film thickness of 10 to 200 μm and a film density of 99% or more and 100% or less. 
     
     
         11 . The plasma processing apparatus according to  claim 1 , wherein the yttrium oxide particles whose grain boundary is confirmable have an average particle diameter of 2 μm or less. 
     
     
         12 . The plasma processing apparatus according to  claim 1 , wherein an average particle diameter of the yttrium oxide particles is 5 μm or less. 
     
     
         13 . The plasma processing apparatus according to  claim 1 , wherein, when an XRD analysis is performed on the yttrium oxide film, a ratio Im/Ic is 0.2 to 0.6, where Ic is a strongest peak of a cubic crystal and Im is a strongest peak of a monoclinic crystal. 
     
     
         14 . The plasma processing apparatus according to  claim 1 , wherein a surface roughness Ra of the yttrium oxide film is 3 μm or less. 
     
     
         15 . The plasma processing apparatus according to  claim 1 , wherein the yttrium oxide film is formed on an inner wall of the chamber and a surface of a structural member in the chamber via an aluminum oxide film. 
     
     
         16 . The plasma processing apparatus according to  claim 15 , wherein the aluminum oxide film has an a structure.