Method for Resist Strip in Presence of Low K Dielectric Material and Apparatus for Performing the Same

Abstract

A method and apparatus is provided for using a plasma generated from a processing gas mixture including H 2 O to efficiently strip photoresist material without causing significant damage to exposed, underlying low k dielectric material. The method includes disposing the processing gas mixture including the H 2 O over the wafer. The processing gas mixture including the H 2 O is then transformed into a plasma. The plasma serves to remove the photoresist material from the substrate without adversely affecting the exposed low k dielectric material.

1 . A photoresist stripping chamber, comprising:
 an internal region configured to contain a plasma;   a wafer support structure disposed within the internal region, the wafer support structure configured to hold a wafer in exposure to the plasma;   an H 2 O vapor supply inlet configured to supply H 2 O vapor to the internal region; and   a power supply for transforming the H 2 O vapor within the internal region into the plasma, wherein the plasma is capable of removing photoresist material from the wafer without adversely affecting a low k dielectric material present on the wafer and exposed to the plasma.   
   
   
       2 . A photoresist stripping chamber as recited in  claim 1 , further comprising:
 a heat exchanger configured to maintain a temperature within the internal region within a range extending from about −100° C. to about 20° C.   
   
   
       3 . A photoresist stripping chamber as recited in  claim 1 , wherein the power supply is defined as a radio frequency (RF) power supply configured to apply RF power within a range extending from about 50 Watts to about 2000 Watts. 
   
   
       4 . A photoresist stripping chamber as recited in  claim 1 , further comprising:
 a vacuum port connected to a vacuum source, the vacuum source capable of generating a partial vacuum pressure within the internal region via the vacuum port, the partial vacuum pressure being within a range extending from about 0.001 torr to about 20 torr.   
   
   
       5 . A photoresist stripping chamber as recited in  claim 1 , further comprising:
 an H 2 O vapor source connected to the H 2 O vapor supply inlet, the H 2 O vapor source capable of supplying H 2 O vapor to the internal region via the H 2 O vapor supply inlet at a flow rate within a range extending from about 50 standard cubic centimeters per minute (sccm) to about 3000 sccm.   
   
   
       6 . A photoresist stripping chamber as recited in  claim 1 , wherein the power supply is defined to include a first radio frequency (RF) generator defined to generate a low frequency RF current, and a second RF generator defined to generate a high frequency RF current. 
   
   
       7 . A photoresist stripping chamber as recited in  claim 6 , wherein the low frequency RF current is generated at about 2 megaHertz (MHz), and wherein the high frequency RF current is generated at about 27 MHz. 
   
   
       8 . A photoresist stripping chamber as recited in  claim 1 , further comprising:
 a set of confinement rings disposed around a periphery of the internal region, the set of confinement rings defined to confine the plasma to be generated within the internal region, and defined to control a pressure within the internal region.   
   
   
       9 . A photoresist stripping chamber as recited in  claim 8 , wherein the set of confinement rings are defined to be movable such that a vertical spacing between adjacent confinement rings can be adjusted to effect control of a fluid flow area between adjacent confinement rings through which process gases exit from the internal region. 
   
   
       10 . A photoresist stripping chamber, comprising:
 an internal region configured to contain a plasma;   a wafer support structure disposed within the internal region, the wafer support structure configured to hold a wafer in exposure to the plasma, the wafer support including a number of cooling channels;   a heat exchanger in fluid communication with the number of cooling channels of the wafer support structure, the heat exchanger defined to maintain a temperature of the wafer support structure;   an H 2 O vapor supply inlet configured to supply H 2 O vapor to the internal region; and   a power supply for transforming the H 2 O vapor within the internal region into the plasma, wherein the plasma is capable of removing photoresist material from the wafer without adversely affecting a low k dielectric material present on the wafer and exposed to the plasma.   
   
   
       11 . A photoresist stripping chamber as recited in  claim 10 , wherein the heat exchanger is defined to maintain the temperature of the wafer support structure at less than about 20° C. 
   
   
       12 . A photoresist stripping chamber as recited in  claim 10 , wherein the power supply is defined as a radio frequency (RF) power supply configured to apply RF power within a range extending from about 50 Watts to about 2000 Watts. 
   
   
       13 . A photoresist stripping chamber as recited in  claim 10 , further comprising:
 a vacuum port connected to a vacuum source, the vacuum source capable of generating a partial vacuum pressure within the internal region via the vacuum port, the partial vacuum pressure being within a range extending from about 0.001 torr to about 20 torr.   
   
   
       14 . A photoresist stripping chamber as recited in  claim 10 , further comprising:
 an H 2 O vapor source connected to the H 2 O vapor supply inlet, the H 2 O vapor source capable of supplying H 2 O vapor to the internal region via the H 2 O vapor supply inlet at a flow rate within a range extending from about 50 standard cubic centimeters per minute (sccm) to about 3000 sccm.   
   
   
       15 . A photoresist stripping chamber as recited in  claim 10 , wherein the power supply is defined to include a first radio frequency (RF) generator defined to generate a low frequency RF current, and a second RF generator defined to generate a high frequency RF current. 
   
   
       16 . A photoresist stripping chamber as recited in  claim 15 , wherein the low frequency RF current is generated at about 2 megaHertz (MHz), and wherein the high frequency RF current is generated at about 27 MHz. 
   
   
       17 . A photoresist stripping chamber as recited in  claim 10 , further comprising:
 a set of confinement rings disposed around a periphery of the internal region, the set of confinement rings defined to confine the plasma to be generated within the internal region, and defined to control a pressure within the internal region.   
   
   
       18 . A photoresist stripping chamber as recited in  claim 17 , wherein the set of confinement rings are defined to be movable such that a vertical spacing between adjacent confinement rings can be adjusted to effect control of a fluid flow area between adjacent confinement rings through which process gases exit from the internal region.