Semiconductor Wafer Dicing via Laser Groove Smoothing
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Solution Overview
Problem
The existing semiconductor chip manufacturing methods using plasma dicing result in scored, irregularly shaped boundary grooves, leading to stress concentration and chipping of semiconductor chips during processing and handling.
Innovation Solution
A method involving resist film formation, laser processing to create boundary grooves, followed by a boundary-groove-surface smoothing step using oxygen plasma to smooth and clean the surfaces, and subsequent plasma etching with fluorine-based gas to separate the chips, ensuring smooth cut surfaces and minimizing chipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser beam is used to form boundary grooves in resist film, then cost is reduced by obviating expensive exposure transfer system, but boundary groove surfaces become scored and irregular leading to chipping
Solution Approach 1:
The patent applies preliminary action by performing a surface smoothing treatment on the boundary groove surfaces before the plasma etching step. This treatment removes the scored and irregular surfaces created by laser processing, preventing chipping while maintaining the cost advantage of laser-based boundary groove formation.
2Productivity
If plasma etching is performed on scored boundary groove surfaces, then dicing is achieved, but stress concentration occurs leading to cracks and chip breakage
Solution Approach 1:
The patent performs surface smoothing treatment as a preliminary action before plasma etching. This removes the scored surfaces that would cause stress concentration during dicing, thereby preventing cracks and chip breakage while maintaining efficient plasma etching productivity.
3Ease of operation
If mechanical dicing method is used, then processing is simple, but damage to wafer from bending and physical impact occurs
Solution Approach 1:
The patent replaces the mechanical dicing method with a plasma etching process. This substitution eliminates mechanical contact that causes wafer damage from bending and physical impact, while the process remains operationally simple through automated plasma processing.
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 produces chipping-free, hard-to-crack semiconductor chips by smoothing the boundary groove surfaces before plasma etching, reducing stress concentration and enhancing the durability of the chips.
Implementation Method 1
a laser beam is emitted to boundary sections among semiconductor elements of a resist film, to thus create, in the resist film, boundary grooves which partition the semiconductor elements from each other
Implementation Method 2
the surfaces of the boundary grooves which have assumed an irregular shape in the laser processing step are smoothed by means of plasma of oxygen gas or plasma of a gas mixture containing oxygen as a primary ingredient
Implementation Method 3
etching the uncovered surface of the semiconductor wafer in the boundary grooves by means of plasma of fluorine-based gas, to thus separate the semiconductor wafer into individual semiconductor chips
Data Source
AI summary
In a laser processing step S3, boundary sections among semiconductor elements 2 of a resist film 4 are exposed to a laser beam 13a, to thus form in the resist film 4 boundary grooves 5—which partition the semiconductor elements 2 from each other—and to uncover a surface 1b of a semiconductor wafer 1 in the boundary grooves 5. In a plasma etching step S6, the surface 1b of the semiconductor wafer 1 exposed in the boundary grooves 5 is etched by means of plasma Pf of a fluorine-based gas, to thus separate the semiconductor wafer 1 into individual semiconductor chips 1′ along the boundary grooves 5. Between the laser processing step S3 and the plasma etching step S6, there is performed processing pertaining to a boundary-groove-surface smoothing step S5 for smoothing, by means of plasma Po of oxygen gas, surfaces of the boundary grooves 5 having assumed an irregular shape in the laser processing step S3.