Method of depositing a copper seed layer which promotes improved feature surface coverage
First Claim
1. A method of providing a copper seed layer over an interior surface of a feature upon or within a semiconductor substrate, said method comprising:
- depositing said copper seed layer over said interior surface of said feature using copper species wherein at least 30 percent of said species are in the form of copper ions at the time said species contact said substrate surface, and wherein a bias voltage on said substrate surface is adjusted during deposition of said copper seed layer, so that a continuous copper seed layer is formed over said interior surface of said feature.
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Abstract
We have discovered a method of improving step coverage of a copper seed layer deposited over a semiconductor feature surface which is particularly useful for small size features having a high aspect ratio. We have demonstrated that it is possible to increase the copper seed layer coverage simultaneously at the bottom of a high aspect ratio contact via and on the walls of the via by increasing the percentage of the depositing copper species which are ions. The percentage of species ionization which is necessary to obtain sufficient step coverage for the copper seed layer is a function of the aspect ratio of the feature. An increase in the percentage of copper species which are ionized can be achieved using techniques known in the art, including but not limited to applicants'"'"' preferred technique, an inductively coupled RF ion metal plasma.
67 Citations
22 Claims
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1. A method of providing a copper seed layer over an interior surface of a feature upon or within a semiconductor substrate, said method comprising:
- depositing said copper seed layer over said interior surface of said feature using copper species wherein at least 30 percent of said species are in the form of copper ions at the time said species contact said substrate surface, and wherein a bias voltage on said substrate surface is adjusted during deposition of said copper seed layer, so that a continuous copper seed layer is formed over said interior surface of said feature.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of providing a complete copper fill of a semiconductor feature upon or within a semiconductor substrate, said method comprising:
- depositing a continuous copper seed layer over an interior surface of said feature using copper species wherein at least 30 percent of said species are in the form of copper ions at the time said species contact said substrate surface, and wherein a bias voltage on said substrate surface is adjusted during deposition of said copper seed layer; and
subsequently depositing a copper fill layer over said continuous copper seed layer. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
- depositing a continuous copper seed layer over an interior surface of said feature using copper species wherein at least 30 percent of said species are in the form of copper ions at the time said species contact said substrate surface, and wherein a bias voltage on said substrate surface is adjusted during deposition of said copper seed layer; and
Specification