Semiconductor Substrate Groove Design for Stable Dicing
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Solution Overview
Problem
Current methods for separating semiconductor substrates into individual elements, such as MEMS devices, face challenges in achieving efficient separation without damaging the fragile structures, including issues with water-based fracturing, excessive etching, and non-uniform separation leading to strength deterioration and productivity losses.
Innovation Solution
A semiconductor substrate with linear grooves formed on longitudinal and lateral separating lines, excluding intersections, and a method involving anisotropic etching and laser beam irradiation to create modified regions for stable and rectilinear separation, reducing the number of laser scans and avoiding excessive etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a plurality of scans are performed to align modified regions in the thickness direction for thick substrates, then separation can be achieved, but process takt increases
Solution Approach 1:
The patent forms V-grooves by anisotropic etching before laser processing. This preliminary action creates a pre-defined separation path that guides crack propagation, allowing thick substrates to be separated in a single laser scan without needing multiple scans to align modified regions, thereby maintaining high separation quality while improving productivity
Solution Approach 2:
The patent segments the separation process into two distinct stages: first forming V-grooves through anisotropic etching to create the separation path, then using laser processing to form modified regions that initiate cracks along this pre-defined path. This segmentation allows each process to be optimized independently, achieving both high precision and efficiency
2Ease of manufacture
If anisotropic etching is performed to form V-grooves, then separation can be achieved, but excessive etching may occur at intersecting portions leading to substrate strength deterioration
Solution Approach 1:
The patent applies local quality by forming V-grooves only in specific regions where separation is required, while leaving other regions intact to maintain substrate strength. The etching is localized to creating separation paths rather than uniformly etching the entire substrate, including intersecting portions that would compromise structural integrity
Solution Approach 2:
The patent replaces the mechanical stress of excessive etching with a chemical etching process that selectively removes material only where needed. By using anisotropic etching to form V-grooves along predetermined separating lines, the method achieves separation capability without the need for excessive material removal that would weaken the substrate
3Manufacturing precision
If continuous grooves are formed on all separating lines including intersections, then separation rectilinearity improves, but substrate strength deteriorates due to excessive etching
Solution Approach 1:
The patent applies local quality by differentiating between regions requiring V-grooves and regions where substrate strength must be maintained. V-grooves are formed only along separating lines where separation is needed, while intersecting portions and other critical regions are left unetched to preserve structural integrity, achieving both rectilinearity and strength
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 enables stable and efficient separation with improved rectilinearity, reduced process takt, and enhanced mechanical strength of semiconductor devices, while avoiding strength deterioration and maintaining high productivity.
Implementation Method 1
Japanese Patent No. 3408805 discloses a method involving using a laser beam to form a modified region in a semiconductor substrate through multiple photon absorption
Implementation Method 2
another method is to reduce the thickness of a processed portion by forming, in advance, a groove on a separating line through anisotropic etching or the like
Data Source
AI summary
A semiconductor substrate (1) includes a plurality of semiconductor elements (2) in which functional elements are constructed and which is formed in a grid pattern, wherein continuous linear grooves (3) are formed on longitudinal and lateral separating lines (4) that individually separate the plurality of semiconductor elements (2) with the exception of intersections of the separating lines (4) and portions corresponding to corners of each semiconductor element (2).