Protecting anodes from passivation in alloy plating systems

Patent metadata

Field	Value
Publication number	US-2018371637-A1
Application number	US-201816122589-A
Country	US
Kind code	A1
Filing date	Sep 5, 2018
Priority date	Jun 5, 2012
Publication date	Dec 27, 2018
Grant date	—

Abstract

An apparatus for continuous simultaneous electroplating of two metals having substantially different standard electrodeposition potentials (e.g., for deposition of Sn—Ag alloys) comprises an anode chamber for containing an anolyte comprising ions of a first, less noble metal, (e.g., tin), but not of a second, more noble, metal (e.g., silver) and an active anode; a cathode chamber for containing catholyte including ions of a first metal (e.g., tin), ions of a second, more noble, metal (e.g., silver), and the substrate; a separation structure positioned between the anode chamber and the cathode chamber, where the separation structure substantially prevents transfer of more noble metal from catholyte to the anolyte; and fluidic features and an associated controller coupled to the apparatus and configured to perform continuous electroplating, while maintaining substantially constant concentrations of plating bath components for extended periods of use.

First claim

1 . A leak detection probe for detecting the presence of metal ions in a tin ion containing electrolyte, where the metal ions are of a metal more noble than tin, the leak detection probe comprising:
a first electrode comprising substantially tin metal; a second electrode comprising substantially a second metal more noble than tin; and an electrically insulating separator positioned between the first electrode and the second electrode, wherein the leak detection probe is configured such that the tin ion containing electrolyte flows through the electrically insulating separator and contacts the second electrode during operation.

2 . The leak detection probe of claim 1 , further comprising a resistor electrically connecting the first electrode and the second electrode, wherein the leak detection probe is configured such that voltage across the resistor is used to detect the presence of the metal ions in the tin ion containing electrolyte.

3 . The leak detection probe of claim 1 , wherein the second metal is porous silver.

4 . The leak detection probe of claim 1 , wherein the first electrode is a rod centrally disposed in the leak detection probe, wherein the electrically insulating separator is disposed around at least a portion of the perimeter of the rod, and wherein the second electrode is disposed around at least a portion of an outer perimeter of the electrically insulating separator.

5 . The leak detection probe of claim 4 , further comprising a sense lead connected to the second electrode.

6 . The leak detection probe of claim 1 , wherein the probe has an impedance of between about 10 ohm and 1 ohm.

7 . The leak detection probe of claim 1 , wherein the first electrode comprises low alpha tin.

8 . The leak detection probe of claim 1 , wherein the metal ions detected in the tin ion containing electrolyte are silver ions.

9 . The leak detection probe of claim 1 , wherein the electrically insulating separator comprises an electrolyte permeable membrane.

10 . The leak detection probe of claim 1 , wherein the electrically insulating separator comprises an electrolyte permeable sintered glass or plastic.

11 . The leak detection probe of claim 1 , wherein the first and second electrodes are electrically connected to a power supply.

12 . The leak detection probe of claim 1 , wherein the first and second electrodes are electrically connected to a power supply that is configured to positively bias the second electrode relative to the first electrode.

13 . The leak detection probe of claim 12 , wherein the power supply is configured to maintain a potential between leads to the first and second electrodes at a fixed value.

14 . The leak detection probe of claim 1 , wherein the second electrode is a silver foil electrode.

15 . The leak detection probe of claim 1 , wherein the second electrode comprises sintered silver powder.

Assignees

• Novellus Systems Inc

Inventors

• Chua Lee Peng
• Mayer Steven T
• Porter David W
• Ponnuswamy Thomas A

Classifications

• C25D17/10

  Electrodes {, e.g. composition, counter electrode} · CPC title

• C25D17/001

  Apparatus specially adapted for electrolytic coating of wafers, e.g. semiconductors or solar cells · CPC title

• C25D21/06

  Filtering {particles other than ions (filtering ions C25D21/22)} · CPC title

• C25D17/002

  Cell separation, e.g. membranes, diaphragms · CPC title

• C25D5/00

  Electroplating characterised by the process; Pretreatment or after-treatment of workpieces · CPC title