Wafer wet cleaning system

Patent metadata

Field	Value
Publication number	US-12162045-B2
Application number	US-201916521187-A
Country	US
Kind code	B2
Filing date	Jul 24, 2019
Priority date	Sep 26, 2018
Publication date	Dec 10, 2024
Grant date	Dec 10, 2024

Abstract

The present disclosure describes a wafer cleaning process in which a drained cleaning solution, which is used to remove metal contaminants from the wafer, is sampled and analyzed to determine the concentration of metal ions in the solution. The wafer cleaning process includes dispensing, in a wafer cleaning station, a chemical solution on one or more waters; collecting the dispensed chemical solution; determining a concentration of contaminants in the chemical solution; in response to the concentration of the contaminants being greater than a baseline value, adjusting one or more parameters in the cleaning process; and in response to the concentration of the contaminants being equal to or less than the baseline value, transferring the one or more wafers out of the wafer cleaning station.

First claim

What is claimed is:

1. A system, comprising:
a cleaning station configured to remove contaminants from one or more wafers via a cleaning process comprising a chemical solution;
a drain collector configured to intermittently collect samples of the chemical solution by diverting a flow of the chemical solution from the cleaning station at sampling intervals;
an analyzer configured to analyze the chemical solution collected in the drain collector to determine a contaminant concentration in the chemical solution; and
a computer unit configured to:
store a plurality of established baseline values determined based on downstream processes, wherein the plurality of established baseline values comprises a first baseline value for a front end of the line (FEOL) wet cleaning process and a second baseline value for a back end of the line (BEOL) wet cleaning process, wherein the first baseline value is lower than the second baseline value;
compare the contaminant concentration to a baseline value of the established baseline values according to a downstream process following the cleaning process;
terminate the cleaning process performed by the cleaning station in response to the contaminant concentration being equal to or less than the baseline value; and
increase a temperature of the chemical solution dispensed by the cleaning station in response to the contaminant concentration being greater than the baseline value.

2. The system of claim 1 , wherein the contaminant concentration indicates an amount of metal contamination on the one or more wafers.

3. The system of claim 1 , wherein the computer unit is further configured to, in response to the contaminant concentration being greater than the baseline value, change a water content in the chemical solution, increase a duration of the cleaning process, or both.

4. The system of claim 1 , wherein the chemical solution comprises one or more of a hydrochloric acid/hydrogen peroxide/deionized (DI) water (HPM) solution, a sulfuric acid/hydrogen peroxide/DI water (SPM) solution, a hydrofluoric acid/DI water (DHF) solution, an ozone solution, and combinations thereof.

5. The system of claim 1 , wherein the analyzer is configured to determine a contaminant concentration using x-ray analysis.

6. The system of claim 5 , wherein the x-ray analysis comprises one or more of x-ray fluorescence (XRF), x-ray photoelectron spectroscopy (XPS), and small-angle x-ray scattering (SAXS).

7. A system, comprising:
a cleaning station configured to perform a cleaning process with a chemical solution on a wafer;
a drain collector configured to collect samples of the chemical solution;
an analyzer configured to analyze the samples;
a computer unit configured to:
store a plurality of baseline values, wherein the plurality of established baseline values comprises a baseline value for a front end of the line (FEOL) wet cleaning process;
compare a contaminant concentration of the samples to the plurality of baseline values; and
in response to the contaminant concentration being greater than at least one baseline value of the plurality of baseline values, increase a temperature of the chemical solution dispensed by the cleaning station.

8. The system of claim 7 , wherein the computer unit is further configured to, in response to the contaminant concentration being equal to or less than the plurality of baseline values, terminate the cleaning process.

9. The system of claim 7 , wherein the contaminant concentration indicates an amount of metal contaminants on the wafer.

10. The system of claim 9 , wherein the metal contaminants comprise copper, iron, tungsten, cobalt, titanium, tantalum, yttrium, zirconium, ruthenium, hafnium, or combinations thereof.

11. The system of claim 7 , wherein the chemical solution comprises a mixture of hydrofluoric acid and deionized water.

12. The system of claim 7 , wherein, in response to the contaminant concentration being greater than the at least one baseline value, the cleaning station is further configured to adjust a duration of the cleaning process.

13. The system of claim 7 , wherein the drain collector is further configured to collect samples of the chemical solution at sampling intervals.

14. A system, comprising:
a cleaning station configured to remove contamination from a wafer via a cleaning process comprising a chemical solution, wherein the cleaning station is configured to collect the chemical solution after the chemical solution has been dispensed onto the wafer;
a drain collector configured to collect a sample of the chemical solution from the cleaning station;
an analyzer configured to analyze the sample to determine a contaminant concentration in the chemical solution;
a computer unit configured to:
store, in a database of the computer, a plurality of baseline values comprising a baseline value for a back end of the line (BEOL) wet cleaning process;
compare the contaminant concentration to at least one baseline value of the plurality of baseline values; and
in response to the contaminant concentration being greater than the at least one baseline value, increase a temperature of the chemical solution.

15. The system of claim 14 , further comprising a main drain configured to divert the chemical solution for neutralization.

16. The system of claim 14 , wherein the computer unit is further configured to, in response to the contaminant concentration being equal to or less than the at least one baseline value, terminate the cleaning process performed by the cleaning station.

17. The system of claim 14 , wherein the contaminant concentration comprises an amount of metal contaminants on the wafer.

18. The system of claim 14 , wherein the chemical solution comprises a mixture of hydrofluoric acid and deionized water.

19. The system of claim 14 , wherein in response to the contaminant concentration being greater than the at least one baseline value, the cleaning station is further configured to adjust a water content of the chemical solution.

20. The system of claim 14 , wherein, in response to the contaminant concentration being greater than the at least one baseline value, the cleaning station is further configured to adjust a duration of the cleaning process.

Assignees

• Taiwan Semiconductor Mfg Co Ltd
• Tawain Semiconductor Mfg Co Ltd

Inventors

• Chao Chih-Wei
• Wang Shu-Yen

Classifications

• H10P72/0414 Primary

  using mainly spraying means, e.g. nozzles · CPC title

• H10P70/20

  Cleaning during device manufacture · CPC title

• H10P70/15

  by wet cleaning only (H10P70/52 takes precedence) · CPC title

• H10P72/0604 Primary

  Process monitoring, e.g. flow or thickness monitoring · CPC title

• B08B2203/007

  Heating the liquid · CPC title