Semiconductor Wafer Backgrinding Kerf Shift Reduction
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Solution Overview
Problem
The semiconductor wafer undergoes kerf shifting and accumulates debris and contaminants during the backgrinding or wafer thinning process, which affects the precision and cleanliness of the manufacturing process.
Innovation Solution
A method involving forming a trench on the semiconductor wafer, applying a protective coating and lamination tape, removing a portion of the substrate to expose the coating, and using a die attach film with a modified region to singulate the wafer, thereby reducing kerf shifting and debris accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If backgrinding or wafer thinning operation is performed, then the thickness of the semiconductor wafer is reduced, but kerf shifting and accumulation of debris and contaminants occur on the surfaces
Solution Approach 1:
A protective coating is applied to the wafer surface before the backgrinding operation begins. This preliminary protective layer prevents debris and contaminants from adhering to the wafer surface during the thinning process, thereby eliminating kerf shifting while still achieving the desired thickness reduction.
Solution Approach 2:
The protective coating acts as an intermediary layer between the wafer surface and the grinding process. This intermediate layer captures and contains debris and contaminants generated during backgrinding, preventing them from directly contacting and displacing the wafer kerf, thus maintaining manufacturing precision.
2Length of stationary object
If backgrinding or wafer thinning operation is performed, then the thickness of the semiconductor wafer is reduced, but debris and contaminants accumulate on the surfaces
Solution Approach 1:
The protective coating is applied in advance before the backgrinding operation to create a barrier that prevents debris and contaminants from accumulating on the wafer surface during the thinning process.
Solution Approach 2:
The protective coating transforms the harmful effect of debris generation into a beneficial outcome by capturing the debris within the coating matrix, converting what would be surface contamination into a contained feature that does not affect wafer quality.
3Manufacturing precision
If protective coating and lamination tape are applied, then kerf shifting and debris accumulation are reduced, but the process complexity increases
Solution Approach 1:
The protective coating and lamination tape are applied as preliminary steps before backgrinding. These additional layers, while increasing process steps, ensure precise kerf control and debris management, with the added complexity offset by the elimination of post-processing corrections.
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 effectively reduces kerf shifting and debris accumulation, enhancing the precision and cleanliness of the semiconductor wafer singulation process, leading to improved manufacturing outcomes.
Implementation Method 1
forming a protective coating over the first surface of the semiconductor wafer and into the trench
Implementation Method 2
expanding the semiconductor wafer to separate the modified region of the die attach film and singulate the semiconductor wafer
Data Source
AI summary
A semiconductor device has a semiconductor wafer with an interconnect structure formed over a first surface of the wafer. A trench is formed in a non-active area of the semiconductor wafer from the first surface partially through the semiconductor wafer. A protective coating is formed over the first surface and into the trench. A lamination tape is applied over the protective coating. A portion of a second surface of the semiconductor wafer is removed by backgrinding or wafer thinning to expose the protecting coating in the trench. A die attach film is applied over the second surface of the semiconductor wafer. A cut or modified region is formed in the die attach film under the trench using a laser. The semiconductor wafer is expanded to separate the cut or modified region of the die attach film and singulate the semiconductor wafer.