Methods and systems for controlling the concentration of a component in a composition with absorption spectroscopy

• US 6,762,832 B2
• Filed: 06/21/2002
• Issued: 07/13/2004
• Est. Priority Date: 07/18/2001
• Status: Expired due to Fees

• Current Assignee: American Liquide America Corporation
• Original Assignee: Air Liquide America LP (Mitsubishi Chemical Group Corp.)
• Inventors: Snyder, David L., Fisher, Matthew L., Misra, Ashutosh
• Primary Examiner(s): Evans, F. L.
• Application Number:
  US10/064,222
• Publication Number:
  US 20030020907A1
• Time in Patent Office: 753 Days
• Field of Search: 356/319, 356/323, 356/325, 356/326, 356/328, 356/300, 438/16
• US Class Current: 356/300
• CPC Class Codes: G01J 3/42 Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry beam switching arrangements G01J3/08
• CPC Class Codes: G01N 2021/3155 Measuring in two spectral ranges, e.g. UV and visible
• CPC Class Codes: G01N 21/33 using ultraviolet light G01N21/39 takes precedence
• CPC Class Codes: G05D 11/138 by sensing the concentration of the mixture, e.g. measuring pH value

Abstract

Provided are methods and systems for controlling the concentration of a component in a composition, and semiconductor processing methods and systems. One exemplary method of controlling the concentration of a component in a composition involves: providing a composition which has a liquid portion, wherein the liquid portion contains a component to be monitored; performing an absorption spectroscopy measurement on a sample of the composition; and controlling the concentration of the component in the composition based on the absorption spectroscopy measurement using a feedback control loop. The invention allows for controlling the concentration of a component in a composition, for example, a corrosion inhibitor in a chemical planarization (CMP) chemical, as well as in pre- and post-CMP storage/treatment chemicals, and can provide real time, accurate process control in a simple and robust manner.

Claims

1. A semiconductor processing method, comprising:

contacting a semiconductor wafer with a solution comprising a component to be monitored;

controlling the concentration of the component by a method comprising;

performing an absorption spectroscopy measurement on a sample of the solution; and

controlling the concentration of the component in the solution based on the absorption spectroscopy measurement using a feedback control loop.

2. The method according to claim 1, wherein the component to be monitored is a corrosion inhibitor.

3. The method according to claim 2, wherein the corrosion inhibitor is benzotriazole, tolyltriazole, imidazole, triazole, benzothiazole, mercaptobenzotriazole, hydroquinone, gallic acid, pyragallol, catechol, recorsinol, or a combination thereof.

4. The method according to claim 1, wherein the concentration of the component in the solution is controlled by adjustment of the amount of the component introduced into the solution.

5. The method according to claim 1, wherein the concentration of the component in the solution is controlled by adjustment of the amount of a diluent introduced into the solution.

6. The method according to claim 1, wherein the absorption spectroscopy measurement is a UV/visible light spectroscopy measurement.

7. The method according to claim 1, further comprising transporting the sample of the solution using a pump.

8. A semiconductor processing system, comprising:

a chemical bath tank containing a solution for treating a semiconductor substrate;

one or more conduits for introducing process materials into the chemical bath, the process materials comprising a component to be monitored;

an absorption spectroscopy measurement apparatus for measuring the concentration of the component in a sample of the solution; and

feedback control means for controlling the concentration of the component in the solution based on the absorption spectroscopy measurement.

9. The system of claim 8, wherein the absorption spectroscopy system comprises a plurality of measurement cells.

10. The system of claim 8, further comprising means for directing the sample to an appropriate measurement cell depending on the concentration of the component to be monitored in the sample.

11. The system according to claim 8, wherein the component to be monitored is a corrosion inhibitor.

12. The system according to claim 11, wherein the corrosion inhibitor is benzotriazole, tolyltriazole, imidazole, triazole, benzothiazole, mercaptobenzotriazole, hydroquinone, gallic acid, pyragallol, catechol, recorsinol, or a combination thereof.

13. The system according to claim 8, wherein the absorption spectroscopy measurement system is a UV/visible light spectroscopy measurement system.

14. The system according to claim 8, further comprising a pump disposed between the chemical bath tank and the absorption spectroscopy measurement apparatus.