Metal Gate Deposition with Pre-Clean Oxide Removal
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Solution Overview
Problem
The formation of oxide layers on metal gate structures during semiconductor fabrication leads to non-uniform thickness and composition, affecting device performance parameters such as threshold voltage and on resistance, especially at smaller technology nodes.
Innovation Solution
Incorporation of a pre-clean chamber within the semiconductor processing apparatus to remove oxide layers directly after forming each metal gate layer, ensuring uniformity by reducing or removing the oxide layer before proceeding to the next deposition step, thereby maintaining consistent metal gate thickness and composition across devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If metal gate layers are formed in multiple deposition chambers, then metal gate structures can be successfully fabricated, but oxide layers form on the metal gate layers during transfer and holding, causing non-uniform thickness and composition
Solution Approach 1:
The patent applies preliminary action by performing a pre-clean process in the first deposition chamber before forming the metal gate layer. This removes oxide layers that may have formed on the substrate during prior processing, preventing oxide contamination of the metal gate layer and ensuring uniform thickness and composition.
Solution Approach 2:
The patent converts the harmful oxide layer formation into a benefit by implementing in-situ cleaning capabilities within the deposition system. The oxide layers that naturally form during transfer and holding are removed through plasma or chemical cleaning processes integrated into the deposition chamber, turning a problematic phenomenon into a controlled part of the manufacturing process.
2Manufacturing precision
If processing time is reduced to minimize oxide formation, then uniformity is improved, but this increases process complexity and requires precise timing control
Solution Approach 1:
The patent merges the deposition and cleaning functions into a single integrated deposition chamber system. By combining the pre-clean process and metal gate deposition in one chamber, the system eliminates the need for complex inter-chamber transfers and reduces process control complexity while maintaining uniformity.
Solution Approach 2:
The patent maintains an inert atmosphere (vacuum or controlled gas environment) throughout the deposition and cleaning processes. This inert environment prevents unwanted oxide formation during processing, allowing for extended processing times without compromising uniformity, thereby reducing the need for precise timing control.
3Manufacturing precision
If in-situ cleaning is performed between deposition steps, then oxide removal is achieved, but processing time increases
Solution Approach 1:
The patent performs the cleaning action preliminarily, before the metal gate layer deposition, within the same chamber. This pre-clean approach removes oxides in advance, and the cleaning process is integrated into the overall deposition timeline, minimizing additional time requirements.
Solution Approach 2:
The patent combines the cleaning and deposition processes in a single integrated sequence within one chamber. By merging these operations and eliminating intermediate transfers, the total processing time is reduced compared to performing cleaning as a separate step in a different chamber.
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 ensures uniform thickness and composition of metal gates, resulting in consistent device performance by minimizing variations in threshold voltage, saturation current, and on resistance, even with varying processing times.
Implementation Method 1
at least partially removing an oxide layer on the metal gate layer
Data Source
AI summary
Semiconductor processing apparatuses and methods are provided in which a pre-clean chamber receives a semiconductor wafer from a metal gate layer deposition chamber and at least partially removes an oxide layer on a metal gate layer. In some embodiments, a semiconductor processing apparatus includes a plurality of metal gate layer deposition chambers. Each of the metal gate layer deposition chambers is configured to form a metal gate layer on a semiconductor wafer. At least one pre-clean chamber of the apparatus is configured to receive the semiconductor wafer from one of the metal gate layer deposition chamber and at least partially remove an oxide layer on the metal gate layer.