Quartz Cover Support Table for Semiconductor Thermal Processing
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Solution Overview
Problem
Existing support table structures in thermal processing systems for semiconductor wafers suffer from metal and organic contamination, uneven temperature distributions, and frequent maintenance due to thermal expansion issues and deposition of unnecessary films, limiting the maximum processing temperature and product yield.
Innovation Solution
A support table structure with heat-resistant upper, side, and lower surface covering members, including an opaque back cover made of quartz glass, to prevent contamination and ensure uniform temperature distribution, along with a heating system divided into concentric zones for flexible power adjustment, embedded in a quartz glass support table to maintain thermal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the support table is made of ceramic material (AlN) with integrated heater, then heating efficiency is improved, but metal contamination and organic contamination occur due to diffusion of heavy metals at high temperatures
Solution Approach 1:
A quartz cover is introduced as an intermediary component between the support table and the processing environment. The quartz cover prevents direct exposure of the AlN support table to process gases, thereby preventing diffusion of heavy metals and organic contamination while maintaining thermal processing efficiency.
Solution Approach 2:
The support table structure combines multiple materials: AlN for the support table body (providing thermal conductivity and mechanical strength), quartz for the cover (providing chemical inertness and contamination prevention), and heater elements (providing heating function). This composite structure resolves the contradiction by assigning different functional requirements to different materials.
2Temperature
If the heater sections are controlled with greatly different power magnitudes, then optimal temperature distribution for wafer processing is achieved, but the support table breaks due to differential thermal expansion
Solution Approach 1:
The heater is divided into multiple sections with independently controllable power magnitudes. By adjusting the power parameters of each section, optimal temperature distribution across the wafer surface is achieved. The quartz cover protects the AlN support table from excessive thermal stress that would otherwise cause structural failure.
Solution Approach 2:
The heater is segmented into multiple independent sections, each capable of being controlled with different power magnitudes. This segmentation allows for precise control of temperature distribution across different zones of the support table, achieving optimal processing conditions while the quartz cover provides structural protection against thermal stress.
3Productivity
If unnecessary films are deposited on the support table surface, then film deposition process is completed, but product yield reduces due to particle formation when films peel off
Solution Approach 1:
The quartz cover acts as a protective intermediary layer that prevents unnecessary films from depositing on the support table surface. By blocking the deposition pathway, the cover eliminates the source of particles that would form when films peel off, thereby maintaining high product yield while still allowing the film deposition process to complete on the wafer.
4Object-generated harmful factors
If transparent quartz plates are used for support table cover, then contamination prevention is achieved, but uneven intrasurface temperature distribution occurs on the wafer
Solution Approach 1:
The patent specifies using opaque or translucent quartz for the cover rather than transparent quartz. The opacity or translucency of the quartz material prevents direct transmission of heating element temperature patterns to the wafer surface, thereby achieving uniform intrasurface temperature distribution while maintaining contamination prevention benefits.
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 solution effectively prevents contamination, maintains uniform intrasurface temperature distribution, reduces maintenance frequency, and allows for higher temperature processing without material degradation, enhancing the thermal processing system's efficiency and product quality.
Implementation Method 1
a heating element with a temperature distribution, and a quartz cover covering an upper surface of the support table. The heating element heats the support table in the temperature distribution
Implementation Method 2
When the quarts plates are transparent, a temperature distribution on the heating element is reflected on the temperature of the wafer and the wafer is hated in an uneven intrasurface temperature distribution
Implementation Method 3
a support table, for supporting a workpiece thereon to subject the workpiece to a predetermined thermal process in a processing vessel, provided with a heating means for heating the workpiece
Implementation Method 4
The cleaning process etches off the unnecessary films by supplying an etching gas into the processing vessel
Data Source
AI summary
A thermal processing system has a processing vessel 4, a support post 30 stood on the bottom wall of the processing vessel 4, and a support table 32 internally provided with a heating means 38 and supported on the support post 30. A workpiece W is placed on the upper surface of the support table 32 and is subjected to a predetermined thermal process. The upper, the side and the lower surface of the support table 32 are covered with heat-resistant covering members 72, 74 and 76 to prevent the thermal diffusion of metal atoms causative of contamination from the support table 32. thus, various types of contamination, such as metal and organic contamination, can be prevented.