Semiconductor Wafer Plasma Dicing Corner Rounding
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Solution Overview
Problem
Conventional plasma dicing methods for semiconductor wafers result in sharp corner portions that are prone to chipping, reducing the transverse rupture strength of semiconductor chips due to difficulties in ion plasma reaching the etching bottom portion and forming protrusive sharp corners.
Innovation Solution
A manufacturing method involving plasma etching on a second surface of a semiconductor wafer with an insulating film, where corner portions on the first surface are removed by charging exposed surfaces with electric charge, followed by removing the insulating film and further etching the second surface to form rounded ridgelines and improve chip strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional plasma dicing is used to divide semiconductor wafers, then the wafer can be separated into individual chips, but sharp corner portions are formed that are prone to chipping and reduce transverse rupture strength
Solution Approach 1:
The patent applies curvature by forming rounded corner portions at the dividing regions of semiconductor chips through plasma etching. Instead of producing sharp corners from conventional dicing, the method creates curved convex surface portions that eliminate stress concentration points, thereby preventing chipping and improving transverse rupture strength while maintaining effective wafer separation
2Productivity
If mechanical dicing is used to cut semiconductor wafers, then division into individual chips is achieved, but the wafer is damaged due to its thin structure
Solution Approach 1:
The patent replaces the mechanical dicing system with a plasma etching process. Instead of using physical blades that can damage thin wafers, the method uses plasma to selectively remove material at dividing regions, achieving chip separation without mechanical contact and thus preserving wafer integrity throughout the process
3Ease of manufacture
If plasma etching is used to remove material at dividing regions, then chip separation is achieved, but ions cannot reach the etching bottom portion effectively
Solution Approach 1:
The patent employs parameter changes by adjusting plasma etching conditions including gas composition, pressure, and power settings to optimize ion penetration and etching uniformity. These parameter modifications enable ions to reach the etching bottom portion effectively, achieving both complete material removal and precise control over etching depth and corner rounding
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
The method effectively reduces chipping and enhances the transverse rupture strength of semiconductor chips by removing sharp corners and forming curved convex surface portions, preventing residual stress and damage from mechanical processing.
Implementation Method 1
performing plasma etching on a second surface of a semiconductor wafer
Implementation Method 2
by performing plasma etching on the semiconductor wafer on which the mask 505 is thus formed, the exposed surface of the surface 501b that is not covered with the mask 505 is etched
Implementation Method 3
removing corner portions on the first surface side put in contact with the insulating film in the device-formation-regions by continuously performing the plasma etching in a state in which exposed surfaces of the insulating film are charged with electric charge due to ions in plasma
Implementation Method 4
removing the exposed insulating film from the second surface after the removal of the corner portions on the first surface side, so that the device-formation-regions are separated into individual semiconductor chips
Implementation Method 5
removing corner portions on the second surface side by subsequently further performing plasma etching on the second surfaces of the semiconductor chips from which the mask has been removed, whereby the semiconductor chips each of which includes the individualized semiconductor device are manufactured
Data Source
AI summary
By performing plasma etching on the second surface of a semiconductor wafer on the first surface of which an insulating film is placed in dividing regions and on the second surface of which a mask for defining the dividing regions are placed, the second surface being located opposite from the first surface, the insulating film is exposed from an etching bottom portion by removing portions that correspond to the dividing regions. Subsequently, by continuously performing the plasma etching in the state in which the exposed surfaces of the insulating film are charged with electric charge due to ions in the plasma, corner portions put in contact with the insulating film are removed. Subsequently, by removing the mask and thereafter performing plasma etching on the second surface, corner portions located on the second surface side are removed.