Compound Semiconductor Substrate Venting for Crack-Free Laser Dicing
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Solution Overview
Problem
The existing methods for manufacturing semiconductor devices using compound semiconductor substrates face challenges such as cracks in the substrate due to pressure from gases generated during the formation of altered layers, which can lead to reduced yield and device reliability.
Innovation Solution
A manufacturing method that involves forming a gas vent recess in the compound semiconductor substrate, creating an altered layer using a laser beam, dividing the substrate at the altered layer, and forming a metal film that covers the divided surface while exposing the gas vent recess, thereby minimizing stress on the semiconductor devices and preventing cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an altered layer is formed inside a compound semiconductor substrate by irradiating with a laser beam, then the substrate can be processed and divided to obtain thinner substrates, but gas generated at the altered layer causes pressure that creates cracks in unintended directions
Solution Approach 1:
The gas vent recess is formed in advance before laser irradiation to provide a predetermined escape path for gas. This preliminary structural preparation prevents gas pressure buildup during the subsequent altered layer formation process, eliminating cracks while maintaining the ability to produce thin substrates with controlled thickness.
Solution Approach 2:
The harmful gas pressure generated during laser processing is converted into a beneficial outcome by directing it through the gas vent recess. The gas that would otherwise cause cracks is now channeled to form or deepen the vent recess, transforming a harmful byproduct into a useful feature that enhances both processing capability and substrate reliability.
2Reliability
If a gas vent recess is formed to reach the altered layer depth, then gas pressure cracks are prevented, but the recess may cause stress concentration during dicing
Solution Approach 1:
The gas vent recess is preliminarily formed with controlled dimensions and positioning before dicing. By establishing the recess geometry in advance with appropriate depth and width constraints, the design anticipates and prevents stress concentration issues during subsequent dicing operations, maintaining substrate strength while preserving crack prevention functionality.
Solution Approach 2:
The gas vent recess is positioned locally at specific regions where gas generation is most intense, rather than uniformly distributed. This localized approach concentrates the gas venting function where needed most while minimizing the overall impact on substrate structural integrity and reducing stress concentration areas during dicing.
3Ease of manufacture
If the metal film is formed to cover the divided surface, then electrode formation is achieved, but the metal film may form inside the gas vent recess causing stress during dicing
Solution Approach 1:
The metal film formation process is selectively applied to exclude the gas vent recess interior from metal deposition. By extracting or excluding the recess region from the metal film coverage, the solution achieves electrode formation on the divided surface while preventing metal accumulation inside the recess that would cause stress concentration and cracking during dicing.
Solution Approach 2:
The metal film is applied with spatially varying coverage: present on the divided surface for electrode functionality, but absent from the gas vent recess interior to prevent stress issues. This local differentiation in metal film presence optimizes both electrical connectivity and mechanical strength during subsequent 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
This method enhances the yield of semiconductor devices by reducing the likelihood of cracks during the dicing process, ensuring higher reliability and accuracy in device manufacturing.
Implementation Method 1
forming an altered layer inside the compound semiconductor substrate to extend along the first surface at a depth corresponding to a range of a depth of the gas vent recess by applying a laser beam
Data Source
AI summary
A manufacturing method of a semiconductor device, includes: forming a gas vent recess in a first surface of a compound semiconductor substrate, which includes a plurality of device regions adjacent to the first surface, along an interface between the plurality of device regions; forming an altered layer inside the compound semiconductor substrate to extend along the first surface at a depth corresponding to a range of a depth of the gas vent recess by applying a laser beam; dividing the compound semiconductor substrate at the altered layer into a first part including the first surface and a second part including a second surface of the compound semiconductor substrate opposite to the first surface; and forming a metal film to cover a divided surface of the first part while exposing the gas vent recess.