Plasma Metal Deposition Pressure Control for Trench Coverage
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Solution Overview
Problem
Conventional metal deposition methods face challenges in achieving adequate coverage in small trenches and vias due to short deposition times and scattering issues, requiring higher ionization ratios for directional deposition.
Innovation Solution
A method involving the ignition of plasma at varying pressures within a processing chamber, where the pressure is gradually decreased in specific time frames to maintain a stable plasma, reducing neutral scattering and increasing ionization ratios for improved metal deposition coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a short metal deposition time is used to reduce metal deposition amount, then deposition time is reduced, but neutral scattering increases causing overhang at structure entrance
Solution Approach 1:
The patent changes the pressure parameter during deposition by implementing a two-stage pressure reduction: first reducing pressure quickly to minimize neutral scattering and overhang formation, then maintaining a low steady-state pressure to ensure adequate metal deposition coverage. This dynamic parameter adjustment resolves the contradiction between short deposition time and uniform coverage.
2Manufacturing precision
If more ions or high ionization ratios are used to facilitate directional deposition, then bottom coverage within structure is improved, but plasma stability becomes more difficult to maintain
Solution Approach 1:
The patent applies preliminary action by first reducing the chamber pressure before initiating or continuing metal deposition. This pre-conditioning of the environment (lower pressure) enables higher ionization ratios and more directional deposition to occur while maintaining plasma stability, as the reduced pressure environment is already prepared to support the required ionization levels.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in enhanced metal deposition coverage on substrates by reducing neutral scattering and increasing ionization ratios, ensuring better bottom coverage within structures.
Implementation Method 1
depositing sputter material from a target disposed within the processing volume
Implementation Method 2
igniting a plasma at a first pressure within a processing volume of a process chamber
Data Source
AI summary
Methods and apparatus for processing a substrate are provided herein. A method, for example, includes igniting a plasma at a first pressure within a processing volume of a process chamber; depositing sputter material from a target disposed within the processing volume while decreasing the first pressure to a second pressure within a first time frame while maintaining the plasma; continuing to deposit sputter material from the target while decreasing the second pressure to a third pressure within a second time frame less than the first time frame while maintaining the plasma; and continuing to deposit sputter material from the target while maintaining the third pressure for a third time frame that is greater than or equal to the second time frame while maintaining the plasma.