GAA Cluster Etch Tool Layout for Sidewall Loss Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for forming gate-all-around (GAA) device structures result in significant sidewall loss and variation due to multiple cleaning and etch steps, which negatively impact semiconductor device performance.
Innovation Solution
A cluster tool and processing method that minimizes sidewall loss and variation by reducing the number of cleaning steps through an integrated system with independently connected processing chambers, including a first etch chamber for removing dummy gate polysilicon, a second etch chamber for removing dummy gate oxide, and a third etch chamber for removing sacrificial layers, allowing for in situ wet etching and reducing exposure to ambient environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple cleaning and etch steps are used to form GAA device structures, then the structures can be formed with conventional methods, but significant sidewall loss and variation occur
Solution Approach 1:
The patent divides the processing system into multiple independently connected processing chambers (first etch chamber, second etch chamber, third etch chamber) that can perform different etching operations sequentially without requiring wafer removal and cleaning between steps. This segmentation allows continuous processing while maintaining spacer material integrity, resolving the contradiction between conventional process compatibility and sidewall loss control.
Solution Approach 2:
The patent implements continuous processing by eliminating idle time and cleaning steps between etching operations. The wafer remains in the vacuum environment and proceeds directly from one etching operation to the next, maintaining process continuity. This continuous action prevents spacer material degradation while preserving the ability to form complex GAA structures.
2Ease of operation
If cleaning process is performed before each step of the remove-load-move-move back-reload sequence, then wafers can be transferred between tools, but variation in sidewall material is induced
Solution Approach 1:
The patent merges multiple etching operations into a single integrated vacuum environment with independently connected processing chambers. This eliminates the need to break vacuum and perform cleaning steps between operations, thereby maintaining sidewall material consistency while still enabling sequential processing of different etching steps.
Solution Approach 2:
The patent maintains a vacuum (inert) environment throughout the entire multi-step etching process. By keeping the wafer in vacuum from one etching step to the next without exposure to ambient atmosphere or cleaning interventions, the spacer material remains protected from degradation, ensuring consistent sidewall dimensions.
3Manufacturing precision
If additional sidewall material is deposited to compensate for sidewall loss, then the absolute value of sidewall loss is compensated, but semiconductor device performance is negatively impacted
Solution Approach 1:
The patent performs preliminary protection of the spacer material by conducting all etching operations in a continuous vacuum environment without intermediate cleaning steps. This preliminary action prevents sidewall loss from occurring in the first place, eliminating the need for compensatory deposition and preserving device performance.
Data Source
AI summary
Semiconductor devices (e.g., GAA device structures) and processing methods and cluster tools for forming GAA device structures are described. The cluster tools for forming GAA device structures comprise a first etch chamber, a second etch chamber, and a third etch chamber. Each of the first etch chamber and the second etch chamber independently comprises a single-wafer chamber or an immersion chamber. One or more of the first etch chamber or the second etch chamber may be a wet etch chamber. In some embodiments, at least one of the first etch chamber, the second etch chamber, and the third etch chamber is a dry etch chamber. The cluster tool described herein advantageously reduces the number of cleaning processes, the total time between cleaning and processing operations, variations in time between processing and variation in sidewall loss compared to conventional cluster tools.