Angled Wafer Holder Structure for Uniform Thin-Film Deposition
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Solution Overview
Problem
Thin wafers undergoing deposition processes experience mechanical deformation due to compressive stress, leading to sagging and tilt, resulting in uneven coating thickness and performance variations across the wafer, which reduces yield and increases rejection rates.
Innovation Solution
A wafer holder apparatus with a jig structure and spring structure that includes angled compression surfaces and optimized contact areas to minimize deformation by pre-biasing the wafer against the coating-induced deformation, maintaining flatness and reducing mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a wafer is held flat during deposition, then coating thickness uniformity is improved, but mechanical stress from clamping causes deformation and reduces yield
Solution Approach 1:
The wafer holder apparatus applies a preliminary counter-bending force to the wafer before deposition, creating a pre-deformation that opposes the coating-induced sagging. This preliminary anti-action ensures that as the coating is deposited and causes the wafer to sag, the pre-applied opposite force maintains the wafer surface closer to the nominal coating plane, improving coating thickness uniformity while using optimized contact areas to minimize mechanical stress and crack loss
Solution Approach 2:
The patent implements local quality by optimizing the contact area between the wafer and the holder apparatus. Specifically, the press ring contact width and spring compression surface area are carefully designed to distribute mechanical stress evenly across critical regions of the wafer. This localized optimization of contact geometry ensures adequate support to maintain flatness during deposition while minimizing point-load stresses that could cause cracking and reduce yield
2Stability of the object's composition
If clamping force is increased to reduce wafer movement, then positioning stability is improved, but wafer deformation and crack loss increase
Solution Approach 1:
The patent applies parameter changes by optimizing the contact area parameters between the wafer and holder apparatus. The press ring contact width and spring compression surface area are specifically designed to distribute clamping force over larger areas, reducing contact pressure while maintaining adequate positioning stability. This parameter optimization allows sufficient clamping force to prevent wafer movement during deposition without exceeding the stress threshold that would cause cracking
Solution Approach 2:
The spring structure is pre-loaded to apply a controlled compression force that stabilizes the wafer in the nominal coating plane position before deposition begins. This preliminary action ensures the wafer is properly positioned and supported from the start of the deposition process, preventing movement and instability while the force is carefully calibrated to avoid excessive stress that would cause cracking
3Stability of the object's composition
If contact area between holder and wafer is increased to improve stability, then wafer positioning is improved, but coating area is reduced
Solution Approach 1:
The patent implements local quality by strategically placing contact elements (press ring and spring compression surface) at specific locations on the wafer holder apparatus. These contact areas are positioned to provide maximum stabilization support to the wafer during deposition while being located in regions that minimize the impact on the overall coating surface area. The contact geometry is optimized to concentrate support where needed while leaving the majority of the wafer surface available for coating
Solution Approach 2:
The patent applies partial action by using a press ring with a contact width of at least 3mm, which provides sufficient stabilization force to maintain wafer positioning stability during deposition. This contact width is optimized to be large enough to provide adequate support and distribute stress, yet small enough relative to the overall wafer size that it does not significantly reduce the coating surface area. The spring compression surface area is similarly optimized to provide necessary support while minimizing the covered area
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 enhances wafer yield and improves the performance of components by reducing sagging, crack loss, and variations in coating thickness, thereby increasing the number of functional components produced from a single wafer.
Implementation Method 1
a spring structure to compress an end of the wafer against the first angled surface
Implementation Method 2
a spring structure to compress an end of the wafer against the first angled surface, wherein the spring structure includes: a spring; and a compression surface attached to the spring
Data Source
AI summary
In some implementations, a wafer holder apparatus includes a jig structure to receive a wafer, wherein the jig structure includes a first angled surface with respect to a nominal coating plane; and a spring structure to compress an end of the wafer against the first angled surface, wherein the spring structure includes: a spring; and a compression surface attached to the spring, wherein the compression surface includes a second angled surface matched to the first angled surface.