Substrate Support Heat Shield for Wafer Temperature Uniformity
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Solution Overview
Problem
In vertical batch furnaces, achieving uniform temperature across all substrates, particularly the lower wafers, is challenging due to their proximity to the cold lower door zone, leading to non-uniform heating, slower cooldown, and distortion of airflow during handling.
Innovation Solution
A substrate processing apparatus with a heat shield that covers the substrate support when no substrate or carrier is present, preventing unnecessary heating and maintaining temperature uniformity by using a support heater only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the support heater is continuously activated to maintain temperature uniformity of lower wafers, then temperature uniformity is improved, but energy consumption increases and cooldown time increases
Solution Approach 1:
The support heater is controlled dynamically based on the presence of substrates. The control system activates the support heater only when substrates are loaded on the substrate support, and deactivates it when substrates are removed, allowing the support surface to cool down. This dynamic control resolves the contradiction by maintaining temperature uniformity when needed while reducing energy consumption and enabling cooldown when substrates are absent.
2Temperature
If the support heater is continuously activated, then temperature uniformity is improved, but handling efficiency deteriorates due to distorted airflow
Solution Approach 1:
The support heater operation is dynamically adjusted based on substrate presence. When substrates are present, the heater maintains temperature uniformity. When substrates are removed for handling, the heater is deactivated, allowing normal airflow patterns to restore, thus preventing airflow distortion and maintaining handling efficiency while still achieving temperature uniformity during processing.
3Temperature
If the support heater is activated without substrates, then temperature uniformity is maintained, but cooldown time increases
Solution Approach 1:
The control system performs preliminary action by detecting substrate presence before activating the support heater. When substrates are detected, the heater is activated in advance to prepare the support surface for uniform heating. When substrates are removed, the heater is immediately deactivated, allowing the support surface to cool down quickly without unnecessary heating, thus reducing cooldown time while maintaining temperature uniformity during actual processing.
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
The heat shield ensures consistent and efficient heating, reducing cooldown times and preventing airflow distortion, thereby enhancing temperature uniformity and handling efficiency across all wafers.
Implementation Method 1
a support heater constructed and arranged to heat the support surface
Implementation Method 2
a heat shield constructed and arranged to cover and shield the substrate support when no substrate or substrate carrier is on the support surface
Data Source
AI summary
A substrate processing apparatus, comprising a substrate support (32) provided with a support surface (34) for supporting a substrate or a substrate carrier (24) thereon and a support heater (50) constructed and arranged to heat the support surface (34). The apparatus comprises a heat shield constructed and arranged to cover and shield the substrate support (32) when no substrate or substrate carrier (24) is on the support surface.