Semiconductor Wafer Cleaving via Backside Crack Formation
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Solution Overview
Problem
The scribing and breaking method for semiconductor wafer division can lead to residual stress near the surface where element structures are formed, causing chipping or unintended cracks, which degrade the reliability of semiconductor devices.
Innovation Solution
Forming a crack in the thickness direction of the semiconductor wafer on the second surface, opposite to the surface with element structures, and dividing along this crack to isolate residual stress away from the element structures, thereby minimizing its impact on device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a pressing member is pressed against the semiconductor wafer to form a crack along the boundary between adjacent element structures, then the semiconductor wafer can be divided by cleaving from the crack, but residual stress remains in the semiconductor wafer causing chipping or unintended cracks that degrade device reliability
Solution Approach 1:
The patent inverts the conventional approach by pressing the pressing member against the back surface (second surface) of the semiconductor wafer rather than the front surface (first surface) where element structures are formed. This inversion causes the crack to form at a depth that positions residual stress away from the element structures, preventing chipping and cracks while maintaining the benefits of the scribing and breaking method for dividing the wafer.
Solution Approach 2:
The patent applies preliminary action by forming the crack and positioning residual stress before the element structures are fully utilized. By creating the crack along the boundary between adjacent element structures and localizing residual stress in specific regions away from the element structures, the method prepares the wafer for division while preemptively preventing reliability issues that would occur during subsequent device operation.
2Manufacturing precision
If the pressing member is pressed against the first surface of the semiconductor wafer where element structures are formed, then the crack can be formed along the boundary, but residual stress occurs in the region adjacent to the first surface causing chipping or unintended cracks
Solution Approach 1:
The patent inverts the pressing location from the conventional first surface (front surface with element structures) to the second surface (back surface). This inversion ensures that when the pressing member applies force to create a crack along the boundary, the resulting residual stress is localized in regions away from the element structures, eliminating chipping and unintended cracks while maintaining precise crack formation along boundaries.
3Length of moving object
If the scribing and breaking method is used to divide the semiconductor wafer, then the width between adjacent element structures can be reduced, but residual stress causes chipping or unintended cracks during repeated operation
Solution Approach 1:
The patent applies local quality by creating non-uniform stress distribution through strategic positioning of the pressing member. The residual stress is localized in specific regions away from the element structures (such as in the substrate region or inter-element regions), while the element structure regions maintain low stress levels. This localized stress management enables reduced width between element structures without compromising reliability.
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 method reduces the likelihood of performance degradation due to residual stress, ensuring high reliability of semiconductor devices even if chipping or cracking occurs, as the stress is localized away from the functional surface.
Implementation Method 1
a pressing member is pressed against a semiconductor wafer to generate stress inside the semiconductor wafer, thereby to form a crack
Implementation Method 2
the pressing member is pressed against the semiconductor wafer on the second surface side to apply a stress in a region adjacent to the second surface in the semiconductor wafer
Data Source
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AI summary
A manufacturing method of a semiconductor device (10) includes: forming a plurality of element structures (6) in a form of matrix on a first surface (2a) of a semiconductor wafer (2); forming a crack (5) extending in a thickness direction of the semiconductor wafer (2) along a boundary between the element structures (6) adjacent to each other by pressing a pressing member (60) against a second surface (2b) of the semiconductor wafer (2) opposite to the first surface (2a) along the boundary; and dividing the semiconductor wafer (2) along the boundary by pressing a dividing member (62) against the semiconductor wafer (2) on a first surface side along the boundary.