Capacitively-Coupled Plasma Reactor Gap Fill
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Solution Overview
Problem
Current methods for depositing dielectric films into gaps on semiconductor wafers face challenges such as void formation, high resistance, contamination, and increased complexity and cost due to limitations in conformality and throughput, especially in high aspect ratio gaps.
Innovation Solution
An integrated apparatus and method that switches between deposition and etch modes using low-frequency and high-frequency RF generators in a capacitively-coupled plasma reactor, allowing for anisotropic etching and subsequent dielectric layer deposition to prevent voids and ensure conformal filling of gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ALD processes are used for gap fill, then conformality is improved, but processing time increases and throughput decreases
Solution Approach 1:
The patent combines deposition and etch processes into a single integrated apparatus with a unified chamber design. The showerhead and pedestal configuration allows alternating between deposition mode (showerhead powered) and etch mode (pedestal powered) without chamber transitions, merging two previously separate process steps into one continuous operation.
Solution Approach 2:
The patent employs periodic alternation between deposition and etch cycles within the same chamber. The system switches between depositing dielectric material and performing anisotropic etching to create tapered profiles, repeating this sequence to progressively fill high aspect ratio gaps while maintaining conformality and preventing voids.
2Reliability
If multi-step deposition-etch-deposition processes are used, then void formation is prevented, but process complexity increases
Solution Approach 1:
The patent integrates deposition and etch functions into a single apparatus with mode-switching capability. The same chamber, showerhead, and pedestal system performs both dielectric deposition and anisotropic etching by alternating power application, eliminating the need for separate process chambers and reducing overall process complexity despite maintaining multiple process steps.
Solution Approach 2:
The showerhead-pedestal system is designed to serve dual functions: deposition mode when showerhead is powered, and etch mode when pedestal is powered. This multi-functional design allows the same hardware to perform multiple process steps, reducing equipment complexity while maintaining the necessary deposition-etch-deposition sequence for void prevention.
3Manufacturing precision
If anisotropic etching is performed to create tapered profiles, then gap fill conformality is improved, but processing time increases
Solution Approach 1:
The patent maintains continuous processing by performing deposition and etching in alternating cycles within the same chamber without intermediate transfers or interruptions. The integrated apparatus enables seamless transition between deposition mode and etch mode, keeping the wafer continuously processed and eliminating idle time between steps.
Solution Approach 2:
The anisotropic etching step creates a tapered profile in advance before final deposition, preparing the gap geometry to facilitate subsequent conformal filling. By pre-shaping the gap walls with controlled etching, the process ensures that following deposition steps can uniformly coat the surfaces, preventing void formation and improving overall fill quality.
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
The solution effectively prevents void formation and enhances the conformality of dielectric film deposition in high aspect ratio gaps, improving the performance and reliability of integrated circuits by integrating deposition and etch processes in a single apparatus.
Implementation Method 1
An integrated apparatus and method that switches between deposition and etch modes using low-frequency and high-frequency RF generators in a capacitively-coupled plasma reactor
Implementation Method 2
deposition of a dielectric film into a gap between features patterned over or into semiconductor wafers
Implementation Method 3
The etching may be done to remedy or prevent void formation in the gap. Specifically, the etch step can be an anisotropic etch that creates a tapered positive slope profile
Data Source
AI summary
Provided are apparatuses and methods for performing deposition and etch processes in an integrated tool. An apparatus may include a plasma processing chamber that is a capacitively-coupled plasma reactor, and the plasma processing chamber can include a showerhead that includes a top electrode and a pedestal that includes a bottom electrode. The apparatus may be configured with an RF hardware configuration so that an RF generator may power the top electrode in a deposition mode and power the bottom electrode in an etch mode. In some implementations, the apparatus can include one or more switches so that at least an HFRF generator is electrically connected to the showerhead in a deposition mode, and the HFRF generator and an LFRF generator is electrically connected to the pedestal and the showerhead is grounded in the etch mode.