Gap Epitaxial Silicon Deposition With Multi-Zone Temperature Control
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Solution Overview
Problem
Conventional methods for forming epitaxial semiconductor material within a gap on a substrate surface face challenges due to unpredictable temperature variations, leading to undesired thickness variations in deposited silicon, which is critical for silicon isolation applications.
Innovation Solution
A method involving a reactor with independent control of multiple heater zones using pyrometers to measure and maintain precise temperature profiles across different substrate locations, allowing selective epitaxial silicon deposition on a bottom surface relative to a sidewall, with etching to achieve uniform thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cyclical deposition and etch processes are used to selectively form semiconductor material, then silicon can be deposited within the gap, but temperature variation across the substrate surface becomes high and unpredictable, leading to undesired thickness variation in the epitaxial silicon
Solution Approach 1:
The heater system is divided into multiple independently controllable zones (first zone and second zone) positioned at different locations on the substrate support. This segmentation allows each zone to be controlled separately to compensate for spatial temperature variations across the substrate surface, thereby achieving uniform silicon thickness deposition.
Solution Approach 2:
Different regions of the substrate receive different heating conditions through the multi-zone heater system. The first and second heater zones can be independently adjusted to provide locally optimized temperature profiles, ensuring that each area of the substrate achieves the desired temperature for uniform epitaxial silicon growth.
2Manufacturing precision
If conventional heating control is used, then the process is simpler, but temperature control precision and stability are insufficient, resulting in poor deposition uniformity
Solution Approach 1:
Pyrometers are positioned to monitor substrate temperatures in real-time, and this temperature feedback is used to independently adjust the power supplied to each heater zone. This closed-loop control system maintains precise temperature stability during deposition, significantly improving deposition uniformity despite the increased system complexity.
Solution Approach 2:
The system replaces simple mechanical heating control with an automated feedback-controlled thermal management system. Pyrometers optically measure substrate temperature without physical contact, and electronic control systems automatically adjust heater power based on these measurements, achieving precision that would be difficult to obtain with manual or simple mechanical control.
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
Achieves reduced non-uniformity in silicon thickness, improving control from 1.5% to 0.16%, and faster temperature stabilization, enhancing the precision of silicon isolation structures in devices like nanosheet or gate-all-around semiconductor devices.
Implementation Method 1
measuring one or more first substrate temperatures at a first substrate location using a first pyrometer, measuring one or more second substrate temperatures at a second substrate location using a second pyrometer
Implementation Method 2
The reactor includes a first zone of one or more heaters and a second zone of one or more heaters
Implementation Method 3
selectively forming epitaxial silicon on a bottom surface of the gap relative to a sidewall of the gap
Implementation Method 4
Cyclical deposition and etch processes have been reported to selectively form semiconductor material
Data Source
AI summary
A method of forming silicon within a gap on a surface of a substrate. The method includes use of two or more pyrometers to measure temperatures at two or more positions on a substrate and/or a substrate support and a plurality of heaters that can be divided into zones of heaters, wherein the heaters or zones of heaters can be independently controlled based on the measured temperatures and desired temperature profiles.