KR-102962546-B1 - Copper electrofill on non-copper liner layers

Abstract

Void-free bottom-up fill of copper within the features is achieved on non-copper liner layers. The non-copper liner layers have higher resistance than copper. An electroplating solution for plating copper on the non-copper liner layers comprises a low copper concentration, a high pH, organic additives, and bromide ions as copper complexing agents. The high pH and bromide ions do not interfere with the activity of the organic additives. In some embodiments, the concentration of copper ions is about 0.2 g/L to about 10 g/L, the concentration of sulfuric acid is about 0.1 g/L to about 10 g/L, and the concentration of bromide ions is about 20 mg/L to about 240 mg/L. In some embodiments, the electroplating solution further comprises chloride ions as additional copper complexing agents at a concentration of about 0.1 mg/L to about 100 mg/L.

Inventors

• 브로건, 리 제이.
• 레이드, 조나단 데이비드
• 리우, 이 후아

Assignees

• 램 리써치 코포레이션

Dates

Publication Date

20260511

Application Date

20190405

Priority Date

20180409

Claims (11)

1. In a method for electroplating copper on the surface of a wafer, A step of receiving the wafer having a plurality of features and a cobalt liner layer on the surface of the wafer; A step of contacting the surface of the wafer with an electroplating solution, wherein the electroplating solution is, Copper ions at a concentration of 0.2 g/L to 3 g/L in the electroplating solution; Accelerator additive; Suppressor additive; A first inorganic complexing agent comprising bromide ions, wherein the concentration of bromide ions in the electroplating solution is 30 mg/L to 200 mg/L; As an acid, the pH of the electroplating solution is greater than 2.0 and the concentration of the acid in the electroplating solution is 0.5 g/L to 5 g/L; and A step of contacting the surface of the wafer with an electroplating solution comprising a second inorganic complexing agent containing chloride ions; and The method includes the step of electroplating copper on the cobalt liner layer to fill the plurality of features with copper, A method of electroplating copper, wherein the above cobalt liner layer covers the bottom portion and side wall of the above features.
2. In Article 1, A method for electroplating copper, wherein the above electroplating solution further comprises a leveler additive.
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6. In Article 1, A method for electroplating copper, wherein the concentration of chloride ions in the electroplating solution is 1 mg/L to 100 mg/L.
7. In Article 1, A method for electroplating copper, wherein the electroplating solution is configured to induce a cathodic overpotential sufficient to prevent the dissolution of the cobalt liner layer on the cobalt liner layer.
8. A copper electroplating solution for electroplating copper on the surface of a wafer having a plurality of features and a cobalt liner layer, Copper ions at a concentration of 0.2 g/L to 3 g/L in the copper electroplating solution; Accelerator additive; Inhibitor additive; A first inorganic complexing agent comprising bromide ions at a concentration of 30 mg/L to 200 mg/L in the copper electroplating solution; A second inorganic complexing agent comprising chloride ions at a concentration of 1 mg/L to 100 mg/L in the copper electroplating solution; and It comprises sulfuric acid at a concentration of 0.5 g/L to 5 g/L in the copper electroplating solution, and The pH of the above copper electroplating solution is greater than 2.0, The above cobalt liner layer is a copper electroplating solution covering the bottom and side walls of the above feature.
9. In Article 8, A copper electroplating solution having a concentration of the inhibitor additive of 30 ppm to 300 ppm.
10. In Article 8, A copper electroplating solution having a concentration of the above-mentioned accelerator additive of 5 ppm to 40 ppm.
11. In any one of Articles 8 through 10, A copper electroplating solution having a concentration of the chloride ions of the above 10 mg/L to 80 mg/L.

Description

Copper electrofill on non-copper liner layers Citation as a reference A PCT application form has been filed concurrently with this specification as part of this application. Each application claiming priority or interest, as identified in the PCT application form filed concurrently with this application, is incorporated by reference in its entirety for all purposes. The formation of metal wire interconnects in integrated circuits (ICs) can be achieved using a damascene or dual damascene process. Typically, trenches or holes are etched into a dielectric material, such as silicon oxide, located on a substrate. The holes or trenches may be lined with one or more liner layers and barrier layers. Subsequently, thin layers of copper may be deposited within the holes or trenches and may serve as copper seed layers. Afterward, the holes or trenches may be filled with copper. Conventional copper deposition typically occurs in two steps. First, a copper seed layer is deposited on a substrate using a PVD process. Next, copper is electroplated onto the seed layer to fill holes or trenches. Techniques have been developed to avoid depositing the copper seed layer using PVD by directly electroplating copper onto barrier or liner layers. However, there are problems with directly electroplating copper onto barrier or liner layers. The background art provided in this specification is intended to provide a general context for the present disclosure. The work of the inventors named in this specification to the extent described in this background art, as well as aspects of the present art that may not otherwise be recognized as prior art at the time of filing, are not explicitly or implicitly acknowledged as prior art for the present disclosure. The present specification provides a method for electroplating copper on the surface of a wafer. The method comprises the steps of receiving a wafer having a plurality of features and a non-copper liner layer on the surface of the wafer, and bringing the surface of the wafer into contact with an electroplating solution. The electroplating solution comprises copper ions, an accelerator additive, an inhibitor additive, and bromide ions at a concentration in the electroplating solution of about 0.2 g/L to about 10 g/L. The pH of the electroplating solution is greater than about 1.0. The method further comprises the step of electroplating copper on the non-copper liner layer to fill the plurality of features with copper. In some embodiments, the electroplating solution further comprises a leveler additive. In some embodiments, the concentration of bromide ions in the electroplating solution is about 20 mg/L to about 240 mg/L. In some embodiments, the non-copper liner layer comprises cobalt or ruthenium. In some embodiments, the electroplating solution comprises sulfuric acid at a concentration in the electroplating solution of about 0.1 g/L to about 10 g/L. In some embodiments, the electroplating solution further comprises chloride ions at a concentration in the electroplating solution of about 1 mg/L to about 100 mg/L. A plurality of copper-filled features are void-free or substantially void-free. In some embodiments, the method further comprises the step of applying a constant potential of about -400 mV to about -2000 mV with respect to Hg/ HgSO₄ to the wafer before or at the time of contact between the electroplating solution and the surface of the wafer. In some embodiments, the method further comprises the step of applying a constant current to a wafer at a current density of about 0.2 mA/ cm² to about 5 mA/ cm² when electroplating copper on a non-copper liner layer. In some embodiments, the electroplating solution is configured to induce a cathodic overpotential sufficient to prevent dissolution of the non-copper liner layer on the non-copper liner layer. Electroplating copper on the non-copper liner layer occurs without depositing a copper seed layer. Another embodiment comprises a copper electroplating solution for electroplating copper on the surface of a wafer having a plurality of features and a non-copper liner layer. The electroplating solution comprises copper ions at a concentration of about 0.2 g/L to about 5 g/L in the copper electroplating solution, an accelerator additive, an inhibitor additive, bromide ions at a concentration of about 20 mg/L to about 240 mg/L in the copper electroplating solution, chloride ions at a concentration of about 1 mg/L to about 100 mg/L in the copper electroplating solution, and sulfuric acid at a concentration of about 0.1 g/L to about 10 g/L in the copper electroplating solution. In some embodiments, the copper electroplating solution contains a leveling agent additive. In some embodiments, the concentration of the inhibitor additive is about 30 ppm to about 300 ppm. In some embodiments, the concentration of the accelerator additive is about 5 ppm to about 40 ppm. In some embodiments, the concentration of chloride ions is about 10 mg/L to ab