Substrate Holder with Recessed Protrusions for Thermal Homogeneity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing substrate holders in CVD and PVD reactors cause uneven surface temperature distribution on substrates due to localized heating at contact points, leading to higher temperatures at support points compared to the rest of the substrate.
Innovation Solution
The substrate holder design features carrying protrusions that project from depressions, with the contact surfaces aligned at a substrate contact level, and are surrounded by trenches to minimize heat transfer from positioning flanks, ensuring the substrate is supported without direct contact, thus reducing lateral heat gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the substrate is supported by carrying protrusions that directly contact the substrate edge, then the substrate is securely positioned, but localized heating occurs at the contact points causing temperature non-uniformity
Solution Approach 1:
The patent introduces a carrier gas as an intermediary medium between the carrying protrusions and the substrate. The substrate is supported by the carrier gas rather than direct contact with protrusions, eliminating localized heat conduction at contact points while maintaining substrate positioning. This resolves the contradiction by mediating the support function to prevent thermal coupling.
Solution Approach 2:
The patent replaces the mechanical contact-based support system with a fluid-based support system using carrier gas. Instead of relying on physical carrying protrusions to support the substrate, the system uses aerostatic or aerodynamic principles where the carrier gas provides the support force, eliminating the thermal conduction path through mechanical contact.
2Device complexity
If the substrate is held close to the bearing area base surface for compact design, then device size is reduced, but heat conduction from the base surface causes temperature gradients
Solution Approach 1:
The patent employs pneumatic principles by using carrier gas to provide both support and thermal isolation. The gas cushion between the substrate and bearing area base surface prevents direct thermal conduction while maintaining close proximity for compact design. This allows the device to remain compact without suffering from heat conduction-induced temperature gradients.
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 design enhances temperature homogeneity across the substrate surface by reducing heat transfer through solid conduction and promoting thermal radiation and convection, maintaining a uniform surface temperature.
Implementation Method 1
Contact heat transmission from the susceptor to the substrate takes place via these carrying protrusions
Implementation Method 2
heat transmission from the base surface of the bearing area to the lower side of the substrate takes place essentially via thermal radiation or convection
Implementation Method 3
heat transmission from the base surface of the bearing area to the lower side of the substrate takes place essentially via thermal radiation or convection by way of the carrier gas located in the process chamber
Data Source
AI summary
A device for holding at least one substrate in a process chamber of a CVD or PVD reactor includes a flat upper side on which at least one bearing area for the at least one substrate is located. An outline contour line corresponding to the outline contour of the substrate is flanked by positioning edges for positioning a respective section of an edge of the substrate. The device further includes carrying protrusions projecting from a bearing area base surface of the bearing area that is surrounded by the outline contour line. The carrying protrusions have contact surfaces that are raised in relation to the bearing area base surface, on which contact surfaces the substrate can be placed. In order to improve the temperature homogeneity of the surface of the substrate, each of the carrying protrusions originate from a recess of the bearing area base surface.