Patterned Susceptor Surface for CVD Wafer Sticking
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Solution Overview
Problem
Conventional substrate-supporting devices in CVD apparatuses suffer from low controllability and significant individual differences in susceptor surface states, leading to varying contact areas with wafers, which results in wafer sticking, poor film uniformity, and increased stress in thin film formation.
Innovation Solution
A substrate-supporting device with a patterned surface featuring continuous regions of high and low elevations, where the high regions support the substrate with a contact area of 20% or less, reducing wafer sticking and improving susceptor surface controllability by maintaining uniform temperature and RF current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the susceptor surface is made smooth and continuous, then the film uniformity is improved, but wafer sticking occurs due to increased contact area
Solution Approach 1:
The susceptor surface is segmented into multiple protruding regions instead of being continuous, creating discrete contact points. This segmentation reduces the total contact area between wafer and susceptor, preventing wafer sticking while maintaining film uniformity through controlled deposition zones.
Solution Approach 2:
The susceptor surface is designed with non-uniform local properties, creating specific protruding regions with defined geometries (circular, rectangular, or triangular patterns). These local structures control the contact areas to prevent sticking while ensuring adequate support and heat distribution for uniform film formation.
2Object-generated harmful factors
If the contact area between wafer and susceptor is reduced to prevent sticking, then wafer sticking is suppressed, but film uniformity and stress control deteriorate
Solution Approach 1:
The susceptor protruding regions are designed with optimized dimensions and spacing that can be adjusted based on wafer size and process requirements. This dynamic design allows the contact area to be precisely controlled to prevent sticking while maintaining sufficient support for uniform film deposition and stress management.
Solution Approach 2:
The geometry, size, and distribution parameters of the protruding regions are systematically optimized to achieve the desired balance between preventing wafer sticking and maintaining film uniformity. By controlling parameters such as protrusion height, base area, and spacing, both contradictory requirements are satisfied simultaneously.
3Object-generated harmful factors
If conventional susceptor surface treatments (blasting, chemical treatment) are applied to reduce contact area, then wafer sticking is reduced, but controllability of susceptor surface state deteriorates
Solution Approach 1:
Instead of applying surface treatments after susceptor fabrication, the protruding region structure is built into the susceptor during manufacturing. This preliminary structural design permanently establishes the contact area reduction without requiring subsequent surface treatments, thereby maintaining full controllability of the susceptor surface state.
Solution Approach 2:
The invention replaces chemical and mechanical surface treatments (blasting, etching) with a structural geometric approach. By using three-dimensional protruding regions instead of two-dimensional surface modifications, the solution achieves contact area reduction through geometry rather than surface chemistry or mechanics, preserving surface controllability.
4Object-generated harmful factors
If the susceptor surface is patterned with discontinuous high regions, then wafer sticking is reduced, but film thickness uniformity worsens
Solution Approach 1:
The protruding regions are designed with asymmetric distributions and varying geometries optimized for specific wafer sizes and deposition patterns. This asymmetric design allows non-uniform contact areas that compensate for natural deposition gradients, maintaining film thickness uniformity while preventing sticking through strategic placement of support regions.
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 effectively suppresses wafer sticking while maintaining controllability, achieving stable and uniform film characteristics without apparatus troubles, even with larger contact areas, by using continuous high regions and dimples to reduce substrate-susceptor contact.
Implementation Method 1
The susceptor 3 supports a wafer 4 on it and heats the wafer continuously by the heater 2 to maintain it at a given temperature (−50° C. to 650° C.)
Implementation Method 2
The gas inlet port 5 and the first electrode 9 are insulated from the reaction chamber 6 and connected to an external first radio-frequency power source 7. A second radio-frequency source 8 may also be connected at this time.
Data Source
AI summary
A substrate-supporting device for CVD having a substrate-supporting region includes: a substrate-supporting surface which is a continuous surface defining a reference plane on which a substrate is placed; and multiple dimples having bottom surfaces lower than the reference plane. The respective dimples are isolated from each other by a portion of the substrate-supporting surface.