CVD Susceptor Ceramic Liners for Thermal Uniformity
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Solution Overview
Problem
In plasma CVD apparatuses, the wide space below the susceptor during film formation leads to non-uniform substrate temperature and abnormal discharges due to heat loss and high-frequency voltage transmission, causing variations in film characteristics and thickness.
Innovation Solution
The CVD apparatus features a chamber with ceramic-lined surfaces and inert gas supply pipes, where the susceptor is movable vertically, and the entry/takeout port is positioned on the side, with ceramic liners covering the inner and outer surfaces to prevent heat loss and voltage interference, using aluminum nitride for the mounting plate and support for thermal conductivity and Al2O3 for the ceramic liners to maintain uniform temperature and prevent abnormal discharges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the space below the susceptor is made wider to facilitate substrate loading and unloading, then the ease of operation is improved, but the temperature uniformity and film quality deteriorate due to heat loss and abnormal discharges
Solution Approach 1:
A partition wall is introduced as an intermediary structure to divide the chamber into an upper reaction chamber and a lower space. This partition wall prevents direct thermal coupling between the susceptor and the lower space while maintaining mechanical support, thereby reducing heat loss and preventing abnormal discharges that would otherwise affect film uniformity
Solution Approach 2:
The chamber space is segmented into distinct regions using a partition wall. The lower surface of the mounting plate and the outer side surface of the support are separated from the lower chamber space, creating isolated thermal zones that prevent heat dissipation to the wider space below while preserving operational accessibility
2Ease of operation
If the space below the susceptor is made wider, then the ease of operation is improved, but the temperature stability deteriorates due to heat flowing out to the space below
Solution Approach 1:
The partition wall acts as a thermal barrier that mediates between the heated susceptor in the upper chamber and the cooler lower space. This intermediary structure blocks heat flow to the wider space below while allowing mechanical support functions to continue, thereby maintaining substrate temperature stability without compromising operational ease
Solution Approach 2:
The partition wall functions as a thin thermal barrier that selectively blocks heat transfer while maintaining structural integrity. This thin film-like structure provides effective thermal isolation between the reaction chamber and the lower space, preventing temperature instability caused by heat loss to the wider space below
3Ease of operation
If the space below the mounting plate becomes wide, then the ease of operation is improved, but harmful factors increase due to abnormal discharge caused by high frequency voltage transmission
Solution Approach 1:
The partition wall serves as an electrical intermediary that blocks high-frequency voltage from transmitting to the lower space. This intermediary structure prevents abnormal discharges in the wider space below while maintaining the mechanical support function, thereby eliminating harmful effects without sacrificing operational accessibility
Solution Approach 2:
The partition wall acts as a thin electrical barrier that prevents high-frequency voltage transmission to the lower chamber space. This thin film structure effectively blocks the propagation of electrical energy that would cause abnormal discharges, thereby eliminating harmful factors while preserving the ease of substrate loading and unloading operations
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 configuration ensures uniform substrate temperature and film thickness, reduces abnormal discharges, and prevents by-product accumulation, resulting in high-quality, uniformly formed thin films with improved thermal management and reduced particle generation.
Implementation Method 1
the inner bottom surface of the chamber, the part of the side of the chamber in the range from the inner bottom surface of the chamber to the position corresponding to the lower surface of the mounting plate when the susceptor is located at the upper end in the vertical direction, the lower surface of the mounting plate, and the outer side surface of the support are coated with ceramic liners
Implementation Method 2
the inner bottom surface of the chamber, the part of the side of the chamber in the range from the inner bottom surface of the chamber to the position corresponding to the lower surface of the mounting plate when the susceptor is located at the upper end in the vertical direction, the lower surface of the mounting plate, and the outer side surface of the support are coated with ceramic liners
Implementation Method 3
using aluminum nitride for the mounting plate and support for thermal conductivity
Data Source
AI summary
A CVD apparatus includes a chamber, a susceptor, an entry/takeout port for a substrate, and a gate valve provided at the entry/takeout port, in which the susceptor has a mounting plate and a support, the entry/takeout port is provided on a part of a side of the chamber, and is provided in a range from an inner bottom surface of the chamber to a position corresponding to the lower surface of the mounting plate when the susceptor is located at an upper end in the vertical direction, and the inner bottom surface of the chamber, the range from the inner bottom surface of the chamber to the position corresponding to the lower surface of the mounting plate when the susceptor is located at the upper end in the vertical direction, the lower surface of the mounting plate, and the outer side surface of the support are coated with ceramic liners.