Wafer Edge Temperature Control for Uniform Film Deposition
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Summary
Problems
In semiconductor processing, radiant heating in CVD processes often results in nonuniform temperature distributions on wafers due to localized heating by infrared lamps, leading to uneven film deposition and potential defects in epitaxial layers.
Innovation solutions
A reactor system with a pyrometer mounting assembly and alignment jig for precise positioning of edge pyrometers to measure wafer edge temperatures, ensuring accurate and repeatable temperature monitoring and control by using a smaller spot size for edge temperature sensing and a fiber optic sensor to identify the wafer edge based on reflectivity differences.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If radiant heating with infrared lamps is used to heat wafers, then heating efficiency is improved, but nonuniform temperature distribution and localized hot spots occur on the substrate surface
Why choose this principle:
The heating system is segmented into multiple independent infrared lamp zones positioned at different locations (front, center, rear) around the reaction chamber. Each zone can be independently controlled to provide localized heating, allowing compensation for temperature nonuniformities and hot spots while maintaining overall heating efficiency.
Principle concept:
If radiant heating with infrared lamps is used to heat wafers, then heating efficiency is improved, but nonuniform temperature distribution and localized hot spots occur on the substrate surface
Why choose this principle:
Different regions of the reaction chamber receive different heating intensities through independently controlled lamp zones. The system applies local quality control by adjusting the radiant heating intensity in specific areas to achieve uniform temperature distribution across the substrate surface, rather than applying uniform heating throughout.
Application Domain
Data Source
AI summary:
A reactor system with a pyrometer mounting assembly and alignment jig for precise positioning of edge pyrometers to measure wafer edge temperatures, ensuring accurate and repeatable temperature monitoring and control by using a smaller spot size for edge temperature sensing and a fiber optic sensor to identify the wafer edge based on reflectivity differences.
Abstract
A reactor system designed to provide accurate monitoring of wafer temperatures during deposition steps. The reactor system includes a pyrometer mounting assembly supporting and positioning three or more pyrometers (e.g., infrared (IR) pyrometers) relative to the reaction chamber to measure a center wafer temperature and an edge wafer temperature as well as reaction chamber temperature. The pyrometer mounting assembly provides a small spot size or temperature sensing area with the edge pyrometer to accurately measure edge wafer temperatures. A jig assembly, and installation method for each tool setup, is provided for use in achieving accurate alignment of the IR pyrometer sensing spot (and the edge pyrometer) relative to the wafer, when the pyrometer mounting assembly is mounted upon a lamp bank in the reactor system or in tool setup. The wafer edge temperature sensing with the reactor system assembled with proper alignment ensures accurate and repeatable measurement of wafer temperatures.