Annular Susceptor Design for Thinned Wafer Stability
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Solution Overview
Problem
Thinned semiconductor wafers are prone to warping and displacement during heating processes in sputtering deposition, leading to potential transportation failures and wafer cracks due to lack of stabilization in existing manufacturing methods.
Innovation Solution
An annular susceptor with a radial vertical cross-section design, featuring a first upper surface for holding the wafer's peripheral portion against gravity and a second upper surface with an inclination closer to vertical, prevents lateral displacement of the wafer during processing by maintaining it in an unrestrained state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If thinned semiconductor wafers are processed without reinforcing members, then manufacturing simplicity is improved, but wafer stability deteriorates leading to warping and displacement
Solution Approach 1:
The susceptor design applies local quality by creating different surface regions with distinct functions: a first upper surface with gentle inclination for holding the wafer against gravity, and a second upper surface with steeper inclination for preventing lateral displacement. This localized functional differentiation stabilizes the wafer without requiring reinforcing members throughout the entire structure.
Solution Approach 2:
The invention transitions from conventional planar susceptor surfaces to a multi-level three-dimensional surface structure. By adding the second upper surface with steeper inclination extending from the first upper surface, the design utilizes vertical dimensionality to create lateral containment, preventing wafer displacement without adding horizontal complexity or reinforcing elements.
2Manufacturing precision
If thinned wafers are heated during processing, then deposition quality is improved, but wafer warping increases causing displacement and cracks
Solution Approach 1:
The susceptor design implements preliminary anti-action by providing the second upper surface with steeper inclination before heating occurs. This pre-configured lateral constraint counteracts the warping tendency that will arise during subsequent heating and deposition processes, preventing displacement and cracks before they can occur.
Solution Approach 2:
The invention changes the geometric parameters of the susceptor surface by introducing the second upper surface with a steeper inclination angle. This parameter modification creates a physical constraint that compensates for thermal-induced warping, allowing high-temperature processing to proceed while maintaining wafer stability.
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
This design effectively prevents wafer displacement and instability during processing, enhancing the reliability of semiconductor device manufacturing by ensuring stable handling and processing of thinned wafers without the need for reinforcing members.
Implementation Method 1
a first upper surface for holding a peripheral portion of a top surface of the semiconductor wafer against gravity
Implementation Method 2
a second upper surface continued to and located outside the first upper surface and having an inclination closer to that of a vertical surface than the inclination of the first upper surface to hold a side surface of the semiconductor wafer against lateral displacement
Data Source
AI summary
In the manufacturing steps of a power-type semiconductor device, after grinding the back surface of the semiconductor wafer, when a metal film is deposited by sputtering deposition over the back surface of the wafer in a preheated state, the wafer is contained in an annular susceptor, and processed. A radial vertical cross section of the annular shape of the susceptor has a first upper surface closer to a horizontal surface for holding a peripheral portion of the top surface of the semiconductor wafer against gravity, and a second upper surface continued to and located outside the first upper surface and closer to a vertical surface for holding a side surface of the semiconductor wafer against lateral displacement.