TSV bath evaluation using field versus feature contrast

Patent metadata

Field	Value
Publication number	US-10508359-B2
Application number	US-201715590718-A
Country	US
Kind code	B2
Filing date	May 9, 2017
Priority date	Jun 14, 2013
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

The embodiments herein relate to methods and apparatus for determining whether a particular test bath is able to successfully fill a feature on a substrate. In various cases, the substrate is a semiconductor substrate and the feature is a through-silicon-via. Generally, two experiments are used: a first experiment simulates the conditions present in a field region of the substrate during the fill process, and the second experiment simulates the conditions present in a feature on the substrate during the fill process. The output from these experiments may be used with various techniques to predict whether the particular bath will result in an adequately filled feature.

First claim

What is claimed is:

1. An apparatus for evaluating whether additives in an electroplating bath of interest meet an electroplating specification, the apparatus comprising:
an analysis chamber;
one or more inlets for providing to the analysis chamber a test bath solution from an electroplating bath of interest and one or more additional solutions;
an outlet for removing fluid from the analysis chamber;
a working electrode;
a power supply; and
a controller configured to cause:
(a) performing a first experiment while the test bath solution is present in the analysis chamber by applying a defined current density to the working electrode, and recording a potential trace output of the working electrode;
(b) contacting the working electrode with an acceleration solution for a duration sufficient to substantially fully saturate the working electrode with accelerator;
(c) performing a second experiment while the test bath solution is present in the analysis chamber by either (i) applying a second defined current density to the working electrode and recording a second potential trace output of the working electrode, or (ii) applying a defined potential to the working electrode and recording a current density trace output; and
(d) determining, based on information contained in one or more of the potential trace output, the second potential trace output, the current density trace output, and calibration data, whether the additives in the electroplating bath of interest meet the electroplating specification.

2. The apparatus of claim 1 , wherein the defined current density applied to the working electrode in (a) approximates a current density experienced in a field region of a substrate when electroplated in the electroplating bath of interest.

3. The apparatus of claim 2 , wherein the second defined current density or the defined potential applied to the working electrode in (c) approximates a current density or potential, respectively, experienced within a feature on the substrate when electroplated in the electroplating bath of interest.

4. An apparatus for evaluating whether additives in an electroplating bath of interest meet an electroplating specification, the apparatus comprising:
an analysis chamber;
one or more inlets for providing to the analysis chamber a test bath solution from an electroplating bath of interest and one or more additional solutions;
an outlet for removing fluid from the analysis chamber;
a working electrode;
a power supply; and
a controller configured to cause:
(a) applying a defined current density to the working electrode while in contact with the electroplating bath of interest,
wherein the defined current density represents a current density experienced in a field region of a substrate when electroplated in the electroplating bath of interest, and
wherein the working electrode's surface is not substantially fully accelerated during (a);

(b) recording a potential trace output of the working electrode when applying the defined current density;
(c) applying a second defined current density or a defined potential to a substantially fully accelerated surface of the working electrode while in contact with the electroplating bath of interest,
wherein the second defined current density or the defined potential represents the current density or potential experienced within a feature on the substrate when electroplated in the electroplating bath of interest;

(d) recording a second potential trace output and/or a current density trace output of the working electrode when applying the second defined current density or the defined potential; and
(e) determining, based on information contained in one or more of the potential trace output, the second potential trace output, and the current density trace output, whether the additives of the electroplating bath of interest meet the electroplating specification.

5. An apparatus for evaluating whether additives in an electroplating bath of interest meet an electroplating specification, the apparatus comprising:
an analysis chamber;
one or more inlets for providing to the analysis chamber a test bath solution from an electroplating bath of interest and one or more additional solutions;
an outlet for removing fluid from the analysis chamber;
a working electrode;
a power supply; and
a controller configured to cause:
(a) applying a current to the working electrode while in contact with the electroplating bath of interest, wherein the working electrode's surface is not substantially fully accelerated during (a);
(b) recording an electrical output of the working electrode produced in response to the applied current in (a);
(c) applying a second current or a potential to a substantially fully accelerated surface of the working electrode while in contact with the electroplating bath of interest,
(d) recording a second electrical output of the working electrode when applying the second current or the potential; and
(e) determining, based on information contained in one or more of the electrical output and the second electrical output, whether the electroplating bath of interest meets the electroplating specification.

6. The apparatus of claim 5 , wherein the current applied to the working electrode in (a) approximates a current density experienced in a field region of a substrate when electroplated in the electroplating bath of interest.

7. The apparatus of claim 6 , wherein the second current or the potential applied to the working electrode in (c) approximates a current density or potential, respectively, experienced within a feature on the substrate when electroplated in the electroplating bath of interest.

8. The apparatus of claim 5 , wherein the controller is configured to cause: prior to (c), contacting the working electrode with an acceleration solution such that the surface of the working electrode becomes substantially fully accelerated.

9. The apparatus of claim 5 , wherein the controller is configured to cause: prior to (a), flowing a standardized electroplating solution into the analysis chamber, electroplating metal onto the working electrode while the working electrode is in contact with the standardized electroplating solution, removing the standardized electroplating solution from the analysis chamber, and flowing the test bath solution into the analysis chamber.

10. The apparatus of claim 9 , wherein the controller is configured to cause: after (b) and before (c), removing metal electroplated onto the working electrode and removing the test bath solution from the analysis chamber, flowing an acceleration solution into the analysis chamber and contacting the working electrode with the acceleration solution such that the surface of the working electrode becomes substantially fully accelerated, removing the acceleration solution from the analysis chamber, rinsing the working electrode to thereby remove unadsorbed acceleration solution, and flowing the test bath solution into the analysis chamber.

11. The apparatus of claim 10 , wherein the metal electroplated onto the working electrode is removed by (i) applying a reverse current to the working electrode to thereby deplate the metal, or (ii) contacting the working electrode with a chemical etching solution to thereby chemically etch the metal.

12. The apparatus of claim 5 , wherein the electroplating specification relates to a capability of the additives in the electroplating bath of interest to fully fill a feature on a substrate through a bottom-up fill mechanism in an acceptable timeframe.

13. The apparatus of claim 12 , wherein the acceptable timeframe is about 1 hour or less.

14. The

Assignees

• Lam Res Corp

Inventors

• Brogan Lee
• Mayer Steven T
• Thorum Matthew
• Richardson Joseph
• Porter David W
• Fu Haiying

Classifications

• C25D21/12 Primary

  Process control or regulation (controlling or regulating in general G05) · CPC title

• H05K3/241

  characterised by the electroplating method; means therefor, e.g. baths or apparatus · CPC title

• C25D21/14 Primary

  Controlled addition of electrolyte components · CPC title

• G01N27/416

  Systems (G01N27/27 takes precedence) · CPC title

• G01N27/413

  Concentration cells using liquid electrolytes {measuring currents or voltages in voltaic cells} · CPC title