Metal Gate Pre-Clean Chamber for Oxide-Free Wafer Transfer
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Solution Overview
Problem
The formation of oxide films on metal gate layers during semiconductor processing leads to undesirable variations in thickness and composition, affecting the performance of transistors, particularly at smaller technology nodes, due to exposure to different environments and hold times within semiconductor processing apparatuses.
Innovation Solution
Incorporating a pre-clean chamber within the semiconductor processing apparatus to partially or completely remove oxide layers from metal gate layers, allowing for direct transfer between metal gate deposition chambers and maintaining uniformity without external exposure, thereby ensuring consistent metal gate layer formation across different wafers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If metal gate layers are formed in multiple different chambers of the semiconductor processing apparatus, then the metal gate structures can be successfully formed, but oxide films form on the metal gate layers during transfer and hold times, causing variations in thickness and composition
Solution Approach 1:
The patent combines multiple deposition chambers into a single integrated chamber, allowing all metal gate layers to be formed without transferring the substrate between chambers. This eliminates the hold time exposure to oxidizing environments and prevents oxide film formation, thereby maintaining uniform thickness and composition of the metal gate layers.
Solution Approach 2:
The patent maintains an inert or reducing atmosphere within the deposition chamber during the entire metal gate formation process. By controlling the chamber environment to prevent oxidation, the metal gate layers remain free from oxide films during formation and transfer, ensuring consistent thickness and composition across all layers.
2Ease of manufacture
If multiple metal gate layers are formed in separate chambers, then each layer can be deposited independently, but the transfer between chambers exposes the metal gate layers to environments that cause oxide film formation
Solution Approach 1:
The patent merges multiple deposition chambers into one, allowing independent deposition of each metal gate layer within the same controlled environment. This eliminates exposure to oxidizing conditions during chamber transfers, preventing oxide film formation while maintaining the ability to independently control deposition parameters for each layer.
Solution Approach 2:
The patent maintains an inert or reducing atmosphere throughout the entire deposition process, protecting metal gate layers from oxidation during and between deposition steps. This environmental control prevents harmful oxide film formation while allowing independent layer deposition.
3Productivity
If hold time is increased to allow for chamber transfers and processing, then more operations can be performed, but oxide films have more time to form on the metal gate layers
Solution Approach 1:
The patent combines multiple deposition operations into a single continuous process within one chamber, eliminating the need for intermediate transfers and hold times. This allows multiple metal gate layers to be deposited sequentially without exposure to oxidizing environments, maintaining uniformity while enabling multiple operations.
Solution Approach 2:
The patent maintains an inert or reducing atmosphere throughout the entire multi-step deposition process, allowing extended processing time for multiple operations without oxide film formation. This environmental control enables increased productivity while preserving layer uniformity.
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 reduces oxide layer thickness significantly, ensuring uniformity in metal gate layer thickness and composition, leading to consistent device performance across devices, including uniform threshold voltage, saturation current, and on resistance of transistors.
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.