Semiconductor Substrate Grinding via Two-Stage Process and Table Processing
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Solution Overview
Problem
Conventional semiconductor substrate grinding methods face challenges in achieving uniform thickness and in-plane uniformity due to foreign substances adhering to the substrate, which affect the flattening and grinding processes, leading to inconsistent results.
Innovation Solution
The method involves a two-stage grinding process where a protection tape is used to protect the device surface, with the first grinding stage removing foreign substances and setting a grinding depth of 50 μm or more to maintain Total Thickness Variation (TTV) within 2 to 4 μm, followed by table processing to support the expected shape of the substrate for the second grinding stage, ensuring uniformity and removing foreign substances while forming a convex part for warpage suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection tape is adhered to the front surface of the wafer and the entire front surface of the base film is cut, then the front surface of the wafer can be retained via the protection tape during grinding, but foreign substances may adhere to the substrate and affect flattening and grinding processes
Solution Approach 1:
The invention extracts and removes foreign substances from the substrate surface through a preliminary cleaning step before grinding. The cleaning process eliminates contaminants that would otherwise interfere with the grinding operation, allowing the protection tape method to proceed without adverse effects from foreign substance adhesion.
Solution Approach 2:
The invention performs a preliminary cleaning action on the substrate surface before the grinding process begins. This preliminary step removes foreign substances that would otherwise adhere during grinding and compromise the flattening process, ensuring that the subsequent grinding operation can proceed with the protection tape in place without contamination issues.
2Manufacturing precision
If the grinding depth is set to 50 μm or more to maintain TTV within 2 to 4 μm, then thickness uniformity is improved, but the process complexity increases with two-stage grinding required
Solution Approach 1:
The invention segments the grinding process into two distinct stages: a first grinding stage that removes foreign substances and establishes a baseline thickness, and a second grinding stage that achieves final precision thickness uniformity with TTV within 2 to 4 μm. This segmentation allows each stage to be optimized for its specific function, with the first stage handling contamination removal and the second stage handling precision thickness control.
Solution Approach 2:
The first grinding stage serves as a preliminary action that removes foreign substances and establishes a consistent starting point for the second grinding stage. By performing this preliminary thickness reduction and cleaning function first, the second stage can focus exclusively on achieving the target TTV precision without being compromised by contaminants or excessive material removal.
3Manufacturing precision
If table processing is performed to support the expected shape of the substrate, then in-plane uniformity is improved, but the device complexity increases
Solution Approach 1:
The table is pre-processed to create a predetermined shape that corresponds to the expected substrate geometry after grinding. This preliminary table preparation ensures that when the substrate is placed on the table during the second grinding stage, the table's shape provides automatic support and guidance that maintains in-plane uniformity without requiring complex real-time adjustments or additional support mechanisms during the grinding operation.
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 approach effectively improves in-plane uniformity and maintains consistent TTV, enhancing the semiconductor substrate's quality by stabilizing the grinding process and preventing warpage through precise table processing and protection tape management.
Implementation Method 1
a protection tape 20 is stuck to a first surface 11 of the semiconductor substrate 10
Implementation Method 2
a first surface 11 of the semiconductor substrate 10 is ground while a second surface 12 of the semiconductor substrate 10 is supported via the protection tape 20
Data Source
AI summary
To provide a manufacturing method of a semiconductor device including a semiconductor substrate, the manufacturing method of the semiconductor device including a sticking for sticking a protection tape to a first surface of the semiconductor substrate, a first grinding for supporting the protection tape and grinding a second surface of the semiconductor substrate that is a surface on the opposite side of the first surface, a protection tape cutting for supporting the second surface of the semiconductor substrate and flattening the protection tape, and a second grinding for supporting the protection tape and grinding the second surface of the semiconductor substrate. In the second grinding, in order to leave a convex part in an outer circumference of the semiconductor substrate, an inside of the convex part may be ground.