KR-102961902-B1 - Electrodeposition of cobalt tungsten films

Abstract

Tungsten-containing metal films may be deposited within recessed features of semiconductor substrates by electrodeposition. The tungsten-containing metal film is electrodeposited under conditions such that the tungsten-containing metal film is oxide-free or substantially oxide-free. Conditions are optimized during electrodeposition for pH, tungsten concentration, and current density, among other parameters. The tungsten-containing metal film may comprise a cobalt-tungsten alloy, a cobalt-nickel-tungsten alloy, or a nickel-tungsten alloy, and the tungsten content of the tungsten-containing metal film is about 1 to 20 atomic percent.

Inventors

• 스펄린, 티게 에이.
• 오포센스키, 에드워드 씨.
• 펭, 장이
• 릭스비, 매튜 에이.
• 리드, 조나단 데이비드

Assignees

• 램 리써치 코포레이션

Dates

Publication Date

20260511

Application Date

20200623

Priority Date

20190628

Claims (20)

1. A method for electroplating a tungsten-containing metal film on a semiconductor substrate, A step of providing a semiconductor substrate to an electroplating apparatus, wherein the semiconductor substrate comprises at least one reset feature and a conductive seed layer exposed on at least the sidewalls of the at least one reset feature; A step of contacting the semiconductor substrate with an electroplating solution within the electroplating apparatus; and An electroplating method comprising the step of electroplating a tungsten-containing metal film and biasing the semiconductor substrate in the electroplating apparatus to the cathode so as to electrochemically fill at least one recessed feature with the tungsten-containing metal film, wherein the tungsten-containing metal film comprises a metal selected from the group consisting of cobalt, nickel, and combinations thereof, the tungsten content of the tungsten-containing metal film is 1 to 20 atomic %, and the electroplating solution has a tungsten content of 4 g/L or less, and the tungsten-containing metal film is substantially free of oxide.
2. In Article 1, The above tungsten-containing metal film is a cobalt tungsten (CoW) film, an electroplating method.
3. In Article 1, The above-described exposed conductive seed layer is a cobalt seed layer, an electroplating method.
4. In Article 1, The above-mentioned at least one resized feature has a width of 40 nm or less, in an electroplating method.
5. In Article 1, The above tungsten-containing metal film is an electroplating method having a sheet resistance of 100 μΩ/cm or less.
6. In Article 1, An electroplating method comprising the step of annealing the electroplated tungsten-containing metal film.
7. In Article 1, The above electroplating solution is an electroplating method having a pH of 6 or less.
8. In any one of paragraphs 1 to 7, The above electroplating solution has a pH of 2 to 4, and is an electroplating method.
9. In any one of paragraphs 1 to 7, An electroplating method comprising the step of biasing the semiconductor substrate as a cathode to electroplat the tungsten-containing metal film, wherein the electroplating is performed at a current density of 12 mA/cm² or less.
10. In any one of paragraphs 1 to 7, An electroplating method wherein the electroplating solution has a tungsten content of 2 g/L or less, and the step of biasing the semiconductor substrate as a cathode to electroplat the tungsten-containing metal film comprises electroplating at a current density of 8 mA/cm² or less.
11. In any one of paragraphs 1 to 7, The above electroplating solution is an electroplating method comprising an inhibitor.
12. delete
13. In an aqueous electroplating solution for electroplating a tungsten-containing metal film, A tungsten source, wherein the tungsten source comprises tungsten-oxygen bonds and the concentration of tungsten in the electroplating aqueous solution is 4 g/L or less; As a source of a metal other than the source of tungsten, the metal source is selected from the group consisting of cobalt, nickel, and combinations thereof; and An electroplating aqueous solution containing acid, wherein the electroplating aqueous solution has a pH of less than 6, and the tungsten-containing metal film is substantially free of oxide.
14. In Article 13, The above metal is cobalt, an electroplating aqueous solution.
15. delete
16. In any one of paragraphs 13 to 14, The above electroplating aqueous solution is an electroplating aqueous solution containing boric acid and having a pH of 2 to 4.
17. In any one of paragraphs 13 to 14, The above electroplating aqueous solution is an electroplating aqueous solution further comprising an inhibitor.
18. In an apparatus for electroplating a tungsten-containing metal film on a semiconductor substrate, An electroplating chamber configured to hold an electroplating solution; A substrate holder configured to hold the semiconductor substrate in the above electroplating solution; Power supply unit; and As a controller, An operation of contacting a semiconductor substrate with an electroplating solution, wherein the semiconductor substrate has a plurality of reset features, and the electroplating solution comprises a source of tungsten and a source of a metal selected from the group consisting of cobalt, nickel, and combinations thereof; and An electroplating apparatus comprising a controller, wherein the operation of electroplating the semiconductor substrate onto the tungsten-containing metal film and biasing the semiconductor substrate toward the cathode to electrochemically fill the plurality of recessed features into the tungsten-containing metal film is composed of program instructions for performing the operation of biasing the semiconductor substrate toward the cathode, wherein the tungsten content in the tungsten-containing metal film is 1 to 20 atomic % and the electroplating solution has a tungsten content of 4 g/L or less, and the tungsten-containing metal film is substantially free of oxide.
19. In Article 18, An electroplating apparatus, wherein the program instructions for performing the operation of biasing the semiconductor substrate to the cathode to electroplat the tungsten-containing metal film include program instructions for providing a current density of 0.25 to 12 mA/cm².
20. In Article 18, The above tungsten-containing metal film is a cobalt tungsten (CoW) film, an electroplating apparatus.

Description

Electrodeposition of cobalt tungsten films Electroplating has long been used in the semiconductor industry to deposit metals onto substrates. Typically, the metal deposited via electroplating is copper, and specific electrolytes and plating methods have been developed to optimize copper deposition on substrates. In damascene processing, electroplating is often used to fill recessed features with metals to fabricate interconnects and other structures. While copper is traditionally used in damascene processing to fill recessed features, other metals, such as cobalt, may also be used to fill recessed features instead of copper. However, the electrolytes and plating methods used to electroplat copper may not be optimal for electroplating other metals. The description of the background technology provided in this specification is generally intended to provide context for the present disclosure. To the extent described in this background technology section, the work of the inventors named herein, as well as aspects of the technology that may not otherwise be recognized as prior art at the time of filing, are not explicitly or implicitly recognized as prior art for the present disclosure. Citation as a reference PCT application forms are submitted concurrently with this specification as part of this application. Each application claiming the advantage or priority identified in the PCT application submitted concurrently with this application is incorporated herein by reference in its entirety for all purposes. A method for electroplating a tungsten-containing metal film on a semiconductor substrate is provided herein. The method comprises the step of providing the semiconductor substrate to an electroplating apparatus, wherein the semiconductor substrate has at least one recessed feature and comprises a conductive seed layer exposed on the sidewalls of at least one recessed feature. The method further comprises the step of contacting the semiconductor substrate with an electroplating solution within the electroplating apparatus, and the step of electroplating the tungsten-containing metal film and biasing the semiconductor substrate within the electroplating apparatus to a cathode to electrochemically fill at least one recessed feature with the tungsten-containing metal film. The tungsten-containing metal film comprises a metal selected from the group consisting of cobalt, nickel, and combinations thereof, and the tungsten content of the tungsten-containing metal film is about 1 to 20 atomic percent. In some embodiments, the tungsten-containing metal film is a cobalt tungsten (CoW) film. In some embodiments, the conductive seed layer is a cobalt seed layer. In some embodiments, the method further includes a step of annealing the electroplated tungsten-containing metal film. In some embodiments, the electroplating solution has a pH of about 2 to 4. In some embodiments, the electroplating solution has a tungsten content of about 4 g/L or less, and the step of biasing the semiconductor substrate to the cathode to electroplat the tungsten-containing metal film comprises electroplating at a current density of about 12 mA/ cm² or less. In some embodiments, the electroplating solution has a tungsten content of about 2 g/L or less, and the step of biasing the semiconductor substrate to the cathode to electroplat a tungsten-containing metal film comprises electroplating at a current density of about 8 mA/ cm² or less. In some embodiments, the tungsten-containing metal film is substantially free of oxide. Another embodiment comprises an aqueous electroplating solution for electroplating a tungsten-containing metal film. The aqueous electroplating solution comprises a source of tungsten, the source of tungsten comprises tungsten-oxygen bonds, and the concentration of tungsten in the aqueous electroplating solution is about 4 g/L or less. In addition to the source of tungsten, the aqueous electroplating solution further comprises a source of metal, the metal is selected from the group consisting of cobalt, nickel, and combinations thereof, and further comprises an acid, and the aqueous electroplating solution has a pH of about 6 or less. In some embodiments, the metal is cobalt. In some embodiments, the concentration of tungsten in the electroplating aqueous solution is about 2 g/L or less. In some embodiments, the electroplating aqueous solution further contains an inhibitor. Another embodiment comprises an apparatus for electroplating a tungsten-containing metal film on a semiconductor substrate. The apparatus comprises an electroplating chamber configured to hold an electroplating solution, a substrate holder configured to hold a semiconductor substrate in the electroplating solution, a power supply, and a controller comprising program instructions for performing the operation of contacting the semiconductor substrate with the electroplating solution—the semiconductor substrate has a plurality of recessed features, and the