Heating Plate Edge Cooling for Thermal Homogeneity
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Solution Overview
Problem
Existing thermal treatment methods for semiconductor substrates, particularly for angular and round substrates, face challenges in achieving temperature homogeneity due to uneven heating and cooling, leading to asymmetrical temperature distribution during the heat-up and cooling phases.
Innovation Solution
A method and device that utilize a heating plate with separately controllable heating elements and a surrounding frame with a gas-conveying gap to actively cool the edge regions, allowing for controlled temperature adjustment through gas flow quantity and temperature, enabling improved temperature homogeneity by reducing temperature differences between the center and edges of the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional heating devices with multiple actively regulated zones are used to heat the center more strongly during heat-up phase, then temperature homogeneity is improved, but device complexity increases
Solution Approach 1:
The heating plate is divided into multiple independently controllable heating zones (first, second, third heating zones) that can be controlled separately. This segmentation allows different regions to be heated at different rates, enabling temperature homogeneity across the substrate while using a relatively simple overall device structure without requiring complex active regulation systems.
Solution Approach 2:
Different regions of the heating plate are assigned different heating characteristics - the center region (first heating zone) receives different heating control compared to the edge regions (second and third heating zones). This local differentiation in heating quality allows the center to be heated more strongly during heat-up phase while edges are cooled more effectively, achieving temperature homogeneity without complex device architecture.
2Manufacturing precision
If gas cooling is applied to edge regions of the heating plate, then temperature homogeneity is improved, but energy loss increases
Solution Approach 1:
Gas cooling is applied locally only to the edge regions (second and third heating zones) of the heating plate, while the center region (first heating zone) receives different treatment. This localized cooling approach improves temperature homogeneity by counteracting the natural tendency for edge regions to cool faster, while minimizing overall energy loss by not cooling the entire heating plate uniformly.
Solution Approach 2:
The natural tendency of edge regions to cool faster and lose heat is converted into a benefit by deliberately applying controlled gas cooling to these regions. This transforms the harmful effect of uneven cooling into a useful feature that actively maintains temperature homogeneity, where the edge cooling that would normally cause temperature differences is harnessed to balance the thermal distribution across the substrate.
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 approach achieves faster and more precise temperature control, resulting in enhanced temperature homogeneity during thermal treatments, particularly beneficial for next-generation photomasks at the 65 nm node, by actively cooling the edge regions of the heating plate, thereby improving the quality of thermal treatments.
Implementation Method 1
a heating plate (4) which is heated by a plurality of separately controllable heating elements (9) on the side of the heating plate facing away from the substrate
Implementation Method 2
the center therefore warms up more slowly relative to the edges... the edges radiate more heat relative to the center
Implementation Method 3
a gas is conveyed through a gap between the frame and at least one edge of the heating plate... the flow-through quantity and/or the temperature of the gas is controlled to influence the temperature of the edge of the heating plate
Data Source
AI summary
This invention relates to a method and a device for the thermal treatment of substrates in which the substrates are held in contact with or a small distance away from a heating plate, which is heated by a plurality of separately controllable heating elements on the side of the heating plate facing away from the substrate, the heating plate being surrounded, at least in its plane, by a frame spaced apart therefrom, and gas being conveyed, in a controlled manner, through a gap between the frame and at least one edge of the heating plate.