Substrate Support Ledge Cantilever Design
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Solution Overview
Problem
Bridging between substrates and susceptor supports during semiconductor material layer deposition can introduce thermal stress and increase the risk of substrate and reactor component damage, particularly in thick film deposition processes.
Innovation Solution
A substrate support design featuring a disc body with a circular concave portion, annular ledge, and rim, where the ledge slopes downward radially outward to cantilever a beveled substrate edge, reducing precursor diffusion and bridging, and optionally incorporating a silicon carbide coating and precoat for enhanced thermal management and substrate protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the substrate is heated to high temperature for thick material layer deposition, then the deposition efficiency is improved, but thermal stress and bridging between substrate and susceptor increase
Solution Approach 1:
The substrate support surface is segmented into multiple zones with different temperatures. The center region maintains high temperature for efficient deposition, while the peripheral region (near the susceptor contact area) is cooled to reduce thermal stress and prevent bridging. This temperature segmentation allows simultaneous achievement of high deposition efficiency and reduced thermal stress.
Solution Approach 2:
Different regions of the substrate support are given different thermal properties. The central area under the substrate has high thermal conductivity to maintain deposition temperature, while the peripheral area near the susceptor has reduced thermal conductivity or active cooling to minimize thermal stress and bridging. This local differentiation of thermal quality resolves the contradiction between overall heating efficiency and localized stress reduction.
2Reliability
If material layer deposition is divided into multiple events with substrate unloading in between, then bridging is reduced and substrate damage risk is limited, but throughput is reduced
Solution Approach 1:
The substrate support is pre-cooled at the peripheral region before deposition begins, and during deposition the cooled peripheral zone continuously prevents bridging formation. This preliminary and continuous cooling action eliminates the need to stop deposition and unload the substrate, thereby maintaining high throughput while preventing substrate damage.
Solution Approach 2:
The cooled peripheral region continuously prevents bridging throughout the entire deposition process, allowing uninterrupted deposition even for thick layers. This continuous protective action eliminates the need for intermittent substrate unloading, maintaining continuous production flow and high throughput while ensuring substrate reliability.
3Stability of the object's composition
If the substrate edge is closely positioned to the susceptor, then support stability is improved, but precursor diffusion into eddies increases and bridging forms
Solution Approach 1:
A gas flow intermediary is introduced between the substrate edge and the susceptor. This gas flow creates a protective barrier that prevents precursor diffusion into the gap region, eliminating bridging formation. The substrate can remain closely positioned to the susceptor for stability, while the gas flow intermediary blocks the harmful precursor transport.
Solution Approach 2:
The harmful precursor material is extracted or removed from the gap region between substrate and susceptor through directed gas flow. By actively removing precursors from this critical zone, bridging is prevented while allowing the substrate to maintain close positioning for stability. The harmful element (precursor) is taken out of the problematic location.
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 design minimizes bridging and associated thermal stress, reducing the risk of substrate and reactor damage while maintaining deposition efficiency, even for thick films, by effectively seating the substrate to limit precursor diffusion and manage thermal loads.
Implementation Method 1
small amounts of material layer precursor flowing through the reactor may transfer (diffuse) from the flow pattern through the reactor to into flow eddies within the reactor
Implementation Method 2
Bridging can introduce thermal stress during deposition of the material layer onto the substrate
Implementation Method 3
optionally incorporating a silicon carbide coating and precoat for enhanced thermal management and substrate protection
Data Source
AI summary
A substrate support includes a disc body with an upper surface and an opposite lower surface arranged along a rotation axis. The upper surface has a circular concave portion extending about the rotation axis, an annular ledge portion extending circumferentially about the concave portion, and an annular rim portion extending circumferentially about the ledge portion connecting to the concave portion of the disc body by the ledge portion of the disc body. The ledge portion slopes downward radially outward from the rotation axis to seat a substrate on the disc body such that a beveled edge of the substrate is cantilevered above the ledge portion of the upper surface of the disc body. Substrate support assemblies, semiconductor processing systems, and film deposition methods are also described.