Bonding Apparatus Selective Peripheral Holding for Wafer Deformation
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Solution Overview
Problem
Conventional bonding apparatuses face challenges in uniformly expanding the bonding wave from the central to the peripheral portions of substrates due to anisotropy in physical properties like Young's modulus and Poisson's ratio, leading to non-uniform deformation and distortion of bonded substrates.
Innovation Solution
A bonding apparatus with a first holding unit to attract and hold a first substrate from above and a second holding unit to hold a second substrate from below, using a striker to press the central portion of the first substrate into contact with the second substrate, while selectively holding the peripheral regions where the bonding wave expands fastest, specifically in the 45° directions for the upper substrate and 45° and 90° directions for the lower substrate, to manage stress distribution and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the bonding wave is expanded from the central portions of the substrates toward the peripheral portions, then the bonding region is formed and expanded uniformly, but the anisotropy in physical properties causes non-uniform expansion and deformation
Solution Approach 1:
The holding unit selectively holds specific peripheral regions (intersecting with directions where bonding wave expands faster) rather than the entire peripheral portion, creating non-uniform local support that compensates for anisotropic expansion differences in different crystal directions
Solution Approach 2:
The holding pattern is made asymmetric by selectively holding only certain peripheral regions rather than uniformly holding all peripheral regions, matching the anisotropic nature of substrate expansion to achieve more uniform overall bonding
2Ease of operation
If the entire peripheral portion of the upper substrate is held, then the bonding process can proceed, but non-uniform stress distribution causes substrate deformation
Solution Approach 1:
Instead of holding the entire peripheral portion uniformly, the holding unit applies localized support only to specific regions that intersect with directions where bonding wave expands faster, creating optimized stress distribution
Solution Approach 2:
The holding pattern parameters are changed from uniform peripheral holding to selective regional holding, adjusting the spatial distribution of holding force to match the anisotropic expansion characteristics of the substrate
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 configuration reduces non-uniformity in the bonding wave expansion, allowing for more uniform stress distribution and minimizing deformation of the combined substrate, thereby enhancing the bonding process by promoting a nearly concentric expansion of the bonding region.
Implementation Method 1
a bonding apparatus configured to bond substrates such as semiconductor wafers by an intermolecular force
Implementation Method 2
The striker is configured to press a central portion of the first substrate from above and bring the first substrate into contact with the second substrate
Data Source
AI summary
Deformation of substrates after the substrates are bonded can be suppressed. A bonding apparatus includes a first holding unit configured to attract and hold a first substrate from above; a second holding unit provided under the first holding unit and configured to attract and hold a second substrate from below; and a striker configured to press a central portion of the first substrate from above and bring the first substrate into contact with the second substrate. The first holding unit is configured to attract and hold a partial region of a peripheral portion of the first substrate, and the first holding unit attracts and holds the region which intersects with a direction, among directions from the central portion of the first substrate toward the peripheral portion thereof, in which a bonding region between the first substrate and the second substrate is expanded faster.