Substrate processing method and substrate processing apparatus

Abstract

A substrate processing method includes applying electroless plating of CoWB onto a Cu interconnection line formed on a wafer W, and then performing a post-cleaning process by use of a cleaning liquid on the target substrate or wafer before a by-product is precipitated on the surface of the CoWB film formed by the electroless plating to cover the Cu interconnection line.

1 . A substrate processing method in a substrate processing apparatus that includes a spin chuck configured to hold and rotate a process object in a horizontal state, a plurality of surrounding members for surrounding a peripheral edge of the process object held on the spin chuck, a plating liquid supply system configured to supply a plating liquid onto the process object held on the spin chuck, and a cleaning liquid supply system configured to supply a cleaning liquid onto the process object held on the spin chuck, the method comprising:
 performing an electroless plating process on a substrate with a Cu (copper) interconnection line formed thereon by supplying the plating liquid onto the substrate to plate the interconnection line with a Co (cobalt) alloy and thereby form a plated surface on the interconnection line; and   then performing a post-cleaning process on the substrate by supplying the cleaning liquid onto the substrate, before the plated surface is dried,   wherein the electroless plating process and the post-cleaning process are continuously performed while the substrate is kept held on the spin chuck in a horizontal state and the substrate is surrounded by different ones of the surrounding members in accordance with the plating liquid and the cleaning liquid, at least for a while, so as to collect or discard the plating liquid and the cleaning liquid separately from each other.   
     
     
         2 . The method according to  claim 1 , wherein the surrounding members includes an inner surrounding member configured to move up and down relative to the spin chuck between a surrounding position for surrounding the peripheral edge of the process object held on the spin chuck and a retreat position for retreating from the peripheral edge of the process object, and an outer surrounding member disposed outside the inner surrounding member and configured to surround the peripheral edge of the process object when the inner surrounding member retreats from the peripheral edge of the process object,
 the electroless plating process is performed by rotating the substrate by the spin chuck and supplying the plating liquid onto the substrate, while surrounding the peripheral edge of the substrate held on the spin chuck by a first surrounding member, which is one of the inner surrounding member and the outer surrounding member, and receiving the plating liquid thrown off from the substrate by the first surrounding member; and   the post-cleaning process is performed by rotating the substrate by the spin chuck and supplying the cleaning liquid onto the substrate, while surrounding the peripheral edge of the substrate held on the spin chuck by a second surrounding member, which is the other of the inner surrounding member and the outer surrounding member, at least for a while, and receiving the cleaning liquid thrown off from the substrate by the second surrounding member.   
     
     
         3 . The method according to  claim 2 , wherein the post-cleaning process includes performing a rinsing process by use of a rinsing liquid as the cleaning liquid, and then performing a chemical liquid process by use of a chemical liquid as the cleaning liquid;
 the rinsing process is performed by rotating the substrate by the spin chuck and supplying the rinsing liquid onto the substrate, while surrounding the peripheral edge of the substrate by the first surrounding member and receiving the rinsing liquid thrown off from the substrate by the first surrounding member; and   the chemical liquid process is performed by rotating the substrate by the spin chuck and supplying the chemical liquid onto the substrate, while surrounding the peripheral edge of the substrate held on the spin chuck by the second surrounding member and receiving the chemical liquid thrown off from the substrate by the second surrounding member.   
     
     
         4 . The method according to  claim 1 , wherein the post-cleaning process includes using as the cleaning liquid a chemical liquid acidic with a pH of 3 or more. 
     
     
         5 . The method according to  claim 4 , wherein the chemical liquid has a pH of 3 to 4. 
     
     
         6 . The method according to  claim 1 , wherein the post-cleaning process includes using as the cleaning liquid a chemical liquid containing a surfactant. 
     
     
         7 . The method according to  claim 6 , wherein the chemical liquid has a surfactant concentration of 0.0001% or more. 
     
     
         8 . The method according to  claim 1 , wherein the post-cleaning process includes performing a rinsing process by use of a rinsing liquid as the cleaning liquid, and then performing a chemical liquid process by use of a chemical liquid as the cleaning liquid. 
     
     
         9 . The method according to  claim 1 , wherein the plating liquid contains a surfactant. 
     
     
         10 . The method according to  claim 1 , wherein the Co alloy is CoWB (cobalt tungsten boron) or CoWP (cobalt tungsten phosphorous). 
     
     
         11 . The method according to  claim 1 , wherein the method is arranged to repeat the electroless plating and the post-cleaning process a plurality of times. 
     
     
         12 . The method according to  claim 1 , wherein the method further comprises performing a pre-cleaning process on the substrate by supplying a pre-cleaning liquid onto the substrate before the electroless plating process, and the pre-cleaning process, the electroless plating, and the post-cleaning process are performed without drying a surface of the substrate corresponding to the plated surface. 
     
     
         13 . The method according to  claim 12 , wherein the pre-cleaning process, the electroless plating process, and the post-cleaning process are repeated a plurality of times. 
     
     
         14 . The method according to  claim 12 , wherein the pre-cleaning process is performed by surrounding the peripheral edge of the substrate held on the spin chuck by one of the surrounding members different from that used in the electroless plating process, at least for a while. 
     
     
         15 . The method according to  claim 12 , wherein the pre-cleaning process includes performing a chemical liquid process by use of a chemical liquid as the pre-cleaning liquid and then performing a rinsing process by use of a rinsing liquid as the pre-cleaning liquid. 
     
     
         16 . The method according to  claim 8 , wherein the rinsing process of the post-cleaning process includes moving up or down one of the surrounding members, which surrounds the substrate, and the spin chuck relative to each other while supplying the rinsing liquid onto the substrate. 
     
     
         17 . The method according to  claim 15 , wherein the rinsing process of the pre-cleaning process includes moving up or down one of the surrounding members, which surrounds the substrate, and the spin chuck relative to each other while supplying the rinsing liquid onto the substrate.