Substrate Support Thermal Voids for Wafer Edge Temperature Gradients
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Solution Overview
Problem
Existing substrate supports with single heating elements struggle to provide adequate temperature gradients between the center and the outer peripheral area of a substrate, leading to deposition uniformity issues during processes like ALD and CVD.
Innovation Solution
The substrate support incorporates multiple heating elements and thermal voids, specifically annular-shaped manifolds defined by plates, to increase temperature gradients across the substrate. These thermal voids provide thermal breaks, allowing for differential heating of the substrate's center and outer edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a single heating element is used in the substrate support, then the structure is simple, but the temperature gradient between the center and outer peripheral area is insufficient
Solution Approach 1:
The substrate support body is divided into multiple plate layers (first plate layer, second plate layer, third plate layer) with heating elements positioned between them. This segmentation allows independent temperature control of different zones, enabling the creation of temperature gradients between the center and outer peripheral areas while maintaining structural organization.
Solution Approach 2:
Different heating elements are applied to different regions of the substrate support. The first heating element is positioned to heat the center area, while the second heating element heats the outer peripheral area. This local differentiation of heating quality creates the desired temperature gradient across the substrate surface.
2Manufacturing precision
If multiple heating elements are added to create temperature gradients, then deposition uniformity improves, but device complexity increases
Solution Approach 1:
Multiple heating elements and plate layers are merged into a single integrated substrate support structure. The heating elements are embedded between the plate layers, combining the heating function with the structural support function, thereby reducing overall system complexity despite the addition of multiple heating zones.
Solution Approach 2:
The plate layers serve multiple functions: they provide structural support for the substrate, act as thermal management components with integrated heating elements, and create the necessary temperature gradients for uniform deposition. This multi-functionality reduces the need for separate components, offsetting the complexity added by multiple heating elements.
3Strength
If plate layers are bonded together to form a unitary structure, then thermal conductivity and structural integrity improve, but manufacturing complexity increases
Solution Approach 1:
The substrate support is manufactured as separate plate layers that are subsequently bonded together. This segmentation allows each plate layer to be manufactured independently using standard machining processes, and the heating elements to be installed between layers before final assembly, simplifying the overall manufacturing process despite the multi-component structure.
Solution Approach 2:
Heating elements are nested between the plate layers during assembly, with the first heating element positioned between the first and second plate layers, and the second heating element between the second and third plate layers. This nested arrangement integrates the heating components within the structural layers, simplifying assembly compared to separate mounting 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
The implementation of multiple heating elements and thermal voids enhances temperature control, achieving gradients of greater than 2° C. or 6° C. between the center and the outer peripheral area, thereby improving deposition uniformity across the substrate.
Implementation Method 1
A heating element can be disposed in the body to heat the pedestal and as a result the substrate during processing. Power is supplied to the heating element
Implementation Method 2
The thermal void is defined by an upper surface of the second intermediate plate and at least one of a lower surface of the first intermediate plate or a lower surface of the top plate. The thermal void provides a thermal break
Data Source
AI summary
A substrate support includes a body and a thermal void. The body is configured to support a substrate during processing of the substrate. The body includes plates including a top plate, a first intermediate plate, a second intermediate plate and a bottom plate. The plates are arranged to form a stack. The first intermediate plate is disposed on the second intermediate plate. The thermal void is defined by an upper surface of the second intermediate plate and at least one of a lower surface of the first intermediate plate or a lower surface of the top plate. The thermal void is annular-shaped.