Pre-heat ring with segmented heaters for epitaxial deposition
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Solution Overview
Problem
Semiconductor substrate processing faces challenges with non-uniform deposition due to varying process gas temperatures, leading to inefficiencies in epitaxial deposition processes, particularly at the edges of substrates.
Innovation Solution
A pre-heat ring assembly within a semiconductor processing chamber, equipped with heaters and temperature sensors, is used to independently control and elevate the temperature of process gases before they reach the substrate, ensuring uniform heating and increased reaction rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If process gas is flowed over substrate without pre-heating, then substrate is protected from excessive heat, but temperature uniformity across substrate surface deteriorates
Solution Approach 1:
The heating system is segmented into multiple independent heating zones (first heating zone at front end, second heating zone at back end, third heating zone at edges) that can be controlled separately to achieve uniform temperature distribution across the substrate surface
Solution Approach 2:
Process gas is pre-heated in the heating zones before reaching the substrate surface, ensuring the gas is at the optimal temperature for deposition while preventing thermal shock to the substrate
2Manufacturing precision
If heating elements are added to improve temperature control, then deposition uniformity improves, but device complexity increases
Solution Approach 1:
Different heating elements are positioned at specific locations (front end, back end, edges) to address local temperature variations, with each heating zone providing targeted heating to achieve uniform deposition across the entire substrate surface
Solution Approach 2:
Temperature sensors are positioned to detect temperatures in different heating zones, providing feedback to the controller which adjusts heating element power to maintain uniform temperature and deposition rate across the substrate
3Productivity
If process gas temperature is increased to improve reaction rate, then deposition speed increases, but temperature control precision deteriorates
Solution Approach 1:
The heating system dynamically adjusts the power to different heating zones based on real-time temperature sensor feedback, allowing the system to maintain precise temperature control while operating at higher temperatures to improve deposition rates
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 solution enhances temperature control, leading to more uniform deposition, higher growth rates, and increased substrate throughput while preventing substrate damage from excessive heat.
Implementation Method 1
a heating element disposed within the front heater volume
Implementation Method 2
one or more heaters disposed adjacent to the pre-heat ring
Implementation Method 3
a reflector disposed within the heater casing and forming a front heater volume
Data Source
AI summary
An apparatus for heating a gas is described. The apparatus is a pre-heat ring and heater assembly positioned in a deposition chamber, such as an epitaxial deposition chamber. The pre-heat ring has a first portion configured to be heated using one or more heaters. The one or more heaters are disposed through a sidewall of the process volume beneath the pre-heat ring and are configured to heat the pre-heat ring so that gas flowed over the pre-heat ring is also heated before being flowed over a substrate. The one or more heaters may include two heaters disposed at distal ends of the first portion of the pre-heat ring. One or more temperature sensors are also configured to measure a temperature of the pre-heat ring.