Split Substrate Carrier with Beveled Conical Interface
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Solution Overview
Problem
Chemical vapor deposition (CVD) processes face challenges in achieving uniform temperature profiles across substrates due to non-uniform thermal expansion between substrate carriers and rotating supports, leading to asymmetric temperature distributions and non-uniform film deposition.
Innovation Solution
A substrate carrier system with a beveled edge forming a conical interface with the rotating support, where the self-locking angle is determined by the coefficient of friction, ensuring secure attachment and uniform thermal expansion, and a split substrate carrier configuration to decouple sections and reduce tensile hoop stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a substrate carrier system is used in CVD processes, then substrate support and processing is enabled, but non-uniform thermal expansion between carrier and rotating support causes asymmetric temperature distributions
Solution Approach 1:
The patent changes the geometric parameters of the interface between substrate carrier and rotating support by introducing a beveled edge at a specific self-locking angle. This angular parameter modification allows the interface to accommodate thermal expansion differences while maintaining axial symmetry, thereby resolving the contradiction between temperature uniformity and thermal expansion compatibility.
Solution Approach 2:
The patent explicitly addresses thermal expansion by designing the beveled interface to self-lock during thermal cycling. The carrier expands thermally and locks onto the rotating support through the beveled geometry, preventing relative motion that would cause asymmetric temperature distribution. This directly resolves the contradiction by utilizing thermal expansion rather than resisting it.
2Strength
If a single-piece substrate carrier is used, then structural simplicity is maintained, but tensile hoop stresses cause structural integrity issues
Solution Approach 1:
The patent divides the substrate carrier into multiple segments rather than using a single-piece design. This segmentation allows each segment to independently manage tensile hoop stresses, preventing structural failure. The increased complexity of having multiple segments is justified by the significant improvement in structural integrity under thermal and mechanical loading.
3Stability of the object's composition
If the substrate carrier is securely attached to the rotating support, then carrier stability is improved, but carrier wobble and eccentricity occur during rotation
Solution Approach 1:
The patent introduces asymmetric beveled edges at the interface between carrier and support. This asymmetric geometry creates a self-centering effect during rotation, where the carrier naturally aligns itself to eliminate wobble and eccentricity. The asymmetric design resolves the contradiction by using the asymmetry of the bevel to achieve symmetric rotational behavior.
Solution Approach 2:
The beveled interface design allows the carrier to self-lock and self-center during thermal expansion and rotation. The system automatically adjusts and maintains optimal positioning without external intervention, preventing wobble and eccentricity while maintaining secure attachment. This self-service mechanism resolves the contradiction between stable attachment and smooth rotation.
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 provides axially symmetric temperature profiles and reduces substrate carrier eccentricity, resulting in improved film uniformity and reduced maintenance costs by preventing substrate carrier wobble and maintaining structural integrity.
Implementation Method 1
The self-locking angle can be determined by the expression tan α>f, where α is the self-locking angle and f is the coefficient of friction
Implementation Method 2
non-uniform thermal expansion between substrate carriers and rotating supports
Data Source
AI summary
A self-centering split substrate carrier that supports a semiconductor substrate in a CVD system includes a first section configured to be centrally located in the split substrate carrier having a top surface with a recessed area for receiving a substrate for CVD processing and comprising a plurality of apertures positioned in an outer surface. A second section formed in a ring-shape having an inner surface configured to receive the first section and an outer surface configured to interface with an edge drive rotation mechanism that rotates the substrate carrier. The inner surface comprising a plurality of boss structures, wherein a respective one of the plurality of boss structures on the inner surface of the second section is configured to fit into a respective one of the plurality of apertures positioned in the outer surface of the first section, so as to improve alignment of the first and the second section of the self-centering split substrate carrier.