Semiconductor Wafer Stacked Dicing Region for Straight Cleavage
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Solution Overview
Problem
The laser dicing technique for semiconductor wafers results in a cleavage line that is not straight, leading to meandering and increased risk of cracks in the semiconductor chip during the thinning process, as the cleavage spreads from a modified portion with low straightness.
Innovation Solution
A semiconductor wafer design with a stacked body in the dicing region, composed of alternately stacked first and second insulating films, which induces a linear cleavage along the stacked body, preventing the meandering of the division line and reducing the risk of cracks by maintaining linearity in both the thickness and plane directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser modification is used to enable cleavage of the semiconductor wafer, then the wafer can be divided into chips, but the cleavage line becomes non-straight and meanders
Solution Approach 1:
A guide film is introduced as an intermediary layer between the laser modification layer and the semiconductor wafer. This guide film has a specific refractive index that differs from both the wafer and the modification layer, causing the laser beam to refract and follow the guide film's path, thereby maintaining a straight cleavage line while still enabling effective wafer division
Solution Approach 2:
The refractive index parameter of the guide film is specifically controlled to be between that of the semiconductor wafer and the laser modification layer. This parameter optimization ensures proper laser beam refraction and guidance, resolving the contradiction between enabling cleavage and maintaining line straightness
2Length of moving object
If the semiconductor wafer is thinned in the polish process after laser modification, then chip thickness is reduced, but the division line curves largely and cracks may reach the device region
Solution Approach 1:
The guide film is formed before the laser modification and thinning processes. This preliminary structure guides the cleavage line to remain straight throughout the subsequent thinning process, preventing the division line from curving into the device region and avoiding cracks that would compromise chip integrity
Solution Approach 2:
The guide film acts as a protective cushion that prevents the cleavage line from deviating during the thinning process. By establishing this guiding structure in advance, the patent prevents potential damage to the device region before it can occur
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 solution ensures a straight and controlled cleavage line during the dicing process, reducing the likelihood of cracks in the semiconductor chip and maintaining the integrity of the chip region by forming a guard ring and using a specific configuration of stacked bodies in both chip and dicing regions.
Implementation Method 1
A laser dicing technique is a method using a laser to modify the inside of a semiconductor wafer to cleave the semiconductor wafer from a modified portion as the starting point
Implementation Method 2
A semiconductor wafer design with a stacked body in the dicing region, composed of alternately stacked first and second insulating films, which induces a linear cleavage along the stacked body
Data Source
AI summary
A semiconductor wafer according to the present embodiment includes a plurality of semiconductor chip regions and a division region. The plurality of semiconductor chip regions have a semiconductor element. The division region is provided between the semiconductor chip regions adjacent to each other. A first stacked body is provided on the division region. The first stacked body is configured with a plurality of first material films and a plurality of second material films alternately stacked.