Heater Pedestal Mesa Height Adjustment for Thermal Uniformity
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Solution Overview
Problem
Semiconductor processing chambers face temperature non-uniformity issues due to gas channels on heater pedestals, leading to variations in substrate temperature and deposited film thickness, which affect reaction rates and processing outcomes.
Innovation Solution
Modifying the physical dimensions and arrangement of elements on the heater pedestal, such as increasing mesa heights, reducing the number of mesas, modifying the depth of chucking channels, and altering the composition and orientation of edge purge gas flows, to enhance thermal conductance and reduce temperature non-uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If gas channels (vacuum channel and edge purge channel) are included on the heater pedestal, then substrate processing functions are improved, but temperature uniformity deteriorates
Solution Approach 1:
The patent applies local quality by modifying specific regions of the heater pedestal - increasing mesa heights in certain concentric regions and adjusting chucking channel depths in specific areas. This creates localized thermal management that compensates for cooling effects from gas channels while maintaining their processing functions.
Solution Approach 2:
The patent changes physical parameters of the heater pedestal elements - modifying mesa heights, chucking channel depths, and edge ring dimensions. These parameter adjustments optimize thermal distribution to counteract the temperature non-uniformity introduced by gas channels.
2Temperature
If mesa heights are increased to improve temperature uniformity, then thermal conductance is enhanced, but device complexity increases
Solution Approach 1:
The patent segments the heater pedestal into concentric regions with different mesa height modifications. This segmentation allows targeted thermal management in different areas without requiring complete redesign of the entire pedestal structure, thereby limiting complexity increases.
3Temperature
If the depth of chucking channels is modified to reduce temperature non-uniformity, then substrate securing function is maintained, but manufacturing precision requirements increase
Solution Approach 1:
The patent modifies the depth parameter of chucking channels as a controlled variable to achieve thermal uniformity. By carefully selecting and implementing specific depth modifications, the patent balances temperature improvement with manufacturability considerations.
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 modifications significantly reduce temperature non-uniformity by up to 40% and thickness non-uniformity of deposited films by up to 60%, improving processing consistency and film quality.
Implementation Method 1
A heater plate is on the base plate... The heater plate comprises two concentric heaters
Implementation Method 2
The pedestals contain a vacuum channel which is used to provide a vacuum to secure the substrate to the pedestal. Another example is an edge purge channel which provides a flow of purge gas
Data Source
AI summary
Some embodiments of the disclosure relate to methods of modifying a heater pedestal to improve temperature and thickness uniformity. Some embodiments of the disclosure relate to the modified heater pedestals with improved temperature and thickness uniformity. In some embodiments, the height of support mesas in different regions of the pedestal are modified to increase temperature uniformity. In some embodiments, the heater elements are moved above the vacuum channel and purge channel to increase temperature uniformity. In some embodiments, the edge ring is modified to be coplanar with the top of a supported substrate.