Plating-deplating waveform based contact cleaning for a substrate electroplating system

Abstract

An electrochemical deposition system configured for electrochemical plating of a substrate includes a chamber, an electrode, a plating cup and a controller. The chamber holds a plating bath. The electrode is disposed in the plating bath. The plating cup includes a contact ring. The contact ring includes contacts. The contacts are immersed in the plating bath. The controller is configured to apply a voltage signal across the contact ring and the electrode to remove residual from the contacts. The voltage signal includes a plating-de-plating waveform. The plating-de-plating waveform includes multiple cycles. Each of the cycles includes a pair of pulses with different polarity.

What is claimed is: 
     
         1 . An electrochemical deposition system configured for electrochemical plating of a substrate, the electrochemical deposition system comprising:
 a chamber holding a plating bath;   an electrode disposed in the plating bath;   a plating cup comprising a contact ring, wherein the contact ring comprises contacts, and wherein the contacts are immersed in the plating bath; and   a controller configured to apply a voltage signal across the contact ring and the electrode to remove residual from the contacts, wherein the voltage signal comprises a plating-de-plating waveform, wherein the plating-de-plating waveform comprises a plurality of cycles, and wherein each of the plurality of cycles includes a pair of pulses with different polarity.   
     
     
         2 . The electrochemical deposition system of  claim 1 , further comprising a membrane disposed in the chamber between the electrode and the contact ring and separating a first portion of the plating bath from a second portion of the plating bath. 
     
     
         3 . The electrochemical deposition system of  claim 1 , wherein a respective portion of the residual is removed during each of the plurality of cycles. 
     
     
         4 . The electrochemical deposition system of  claim 1 , wherein the controller is configured to adjust a voltage of one of the pulses prior to or during a corresponding one of the plurality of cycles. 
     
     
         5 . The electrochemical deposition system of  claim 1 , wherein the controller is configured to adjust a duration of one of the pulses prior to or during a corresponding one of the plurality of cycles. 
     
     
         6 . The electrochemical deposition system of  claim 5 , wherein the controller is configured to adjust a current level of one of the pulses prior to or during a corresponding one of the plurality of cycles. 
     
     
         7 . The electrochemical deposition system of  claim 1 , wherein the controller is configured to:
 determine whether a predetermined criterion is satisfied; and   based on whether the predetermined criterion is satisfied, proceed with applying the voltage signal.   
     
     
         8 . The electrochemical deposition system of  claim 1 , wherein the plating-de-plating waveform includes an initial de-plating pulse prior to the plurality of cycles. 
     
     
         9 . The electrochemical deposition system of  claim 1 , wherein a last de-plating pulse of the plating-de-plating waveform has an extended duration such that a duration of the last de-plating pulse is longer than durations of other de-plating pulses of the plating-de-plating waveform. 
     
     
         10 . The electrochemical deposition system of  claim 1 , wherein the controller is configured to perform one or more passive etching operations to further remove residual from the contacts. 
     
     
         11 . A residual removal method for an electrochemical deposition system configured for electrochemical plating of a substrate, the method comprising:
 removing the substrate from a plating cup, wherein the plating cup includes contacts for contacting the substrate;   immersing the contacts in a plating bath in a chamber of the electrochemical deposition system;   applying a voltage signal across an electrode and the contacts to remove residual from the contacts, wherein the electrode is disposed in the plating bath, wherein the voltage signal includes a plating-de-plating waveform, wherein the plating-de-plating waveform comprises a plurality of cycles, and wherein each of the plurality of cycles includes a pair of pulses with different polarity; and   subsequent to applying the voltage signal, rinsing the contacts with deionized water.   
     
     
         12 . The residual removal method of  claim 11 , wherein a respective portion of the residual is removed during each of the plurality of cycles. 
     
     
         13 . The residual removal method of  claim 11 , further comprising adjusting a voltage of one of the pulses prior to or during a corresponding one of the plurality of cycles. 
     
     
         14 . The residual removal method of  claim 11 , further comprising adjusting a duration of one of the pulses prior to or during a corresponding one of the plurality of cycles. 
     
     
         15 . The residual removal method of  claim 11 , further comprising adjusting a current level of one of the pulses prior to or during a corresponding one of the plurality of cycles. 
     
     
         16 . The residual removal method of  claim 11 , further comprising:
 determining whether a predetermined criterion is satisfied; and   based on whether the predetermined criterion is satisfied, proceeding with the residual removal method.   
     
     
         17 . The residual removal method of  claim 16 , wherein the predetermined criterion includes determining whether a predetermined number of substrates have been processed in the chamber. 
     
     
         18 . The residual removal method of  claim 11 , wherein the plating-de-plating waveform includes an initial de-plating pulse prior to the plurality of cycles. 
     
     
         19 . The residual removal method of  claim 11 , wherein a last de-plating pulse of the plating-de-plating waveform has an extended duration such that a duration of the last de-plating pulse is longer than durations of other de-plating pulses of the plating-de-plating waveform. 
     
     
         20 . The residual removal method of  claim 11 , further comprising performing one or more passive etching operations to further remove residual from the contacts.