Semiconductor Chip Cutting via Laser Modified Regions and Dry Etching
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Solution Overview
Problem
In object cutting methods for semiconductor chips, fractures from modified regions often extend to both main surfaces, leading to incomplete cutting and remaining unprocessed portions.
Innovation Solution
The method involves preparing a single crystal silicon substrate with a functional device layer, irradiating it with laser light to form modified regions, and performing dry etching from the second main surface to create a groove, which allows for reliable cutting of semiconductor chips by extending an extension film stuck to the second main surface, while forming an uneven region with exposed single crystal silicon to prevent strength decrease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser irradiation is performed to form modified regions for cutting semiconductor chips, then the cutting process is initiated, but fractures may extend to both main surfaces causing incomplete cutting and remaining unprocessed portions
Solution Approach 1:
The cutting process is divided into multiple stages: first forming modified regions with laser irradiation, then performing dry etching to create grooves, and finally extending the extension film to complete the separation. This segmentation ensures that each step contributes to complete cutting without fractures extending improperly
Solution Approach 2:
Before extending the extension film for final cutting, the patent performs preliminary dry etching to form grooves along the cut lines. This preliminary action creates controlled pathways that guide the subsequent film extension process, ensuring complete and reliable cutting without unprocessed portions
2Reliability
If dry etching is performed to form grooves for complete cutting, then cutting reliability is improved, but the modified regions may cause strength decrease in the vicinity
Solution Approach 1:
The patent removes the modified regions by performing dry etching that selectively targets and extracts these laser-modified areas. By taking out the modified regions that could compromise strength, the resulting groove structure maintains substrate integrity while ensuring complete cutting separation
3Productivity
If fractures extend to both main surfaces, then cutting separation is achieved, but unprocessed portions remain leading to incomplete manufacturing
Solution Approach 1:
The patent introduces an extension film as an intermediary element that is extended along the grooves to achieve final separation. This intermediary mechanism ensures complete cutting through the substrate without leaving unprocessed portions, while maintaining manufacturing efficiency through automated film extension
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 ensures complete cutting of semiconductor chips with precise control over the cutting process, preventing unprocessed areas and maintaining the integrity of the single crystal silicon substrate.
Implementation Method 1
irradiating the object with laser light to form at least one row of modified regions in the single crystal silicon substrate along each of a plurality of lines to cut and to form a fracture in the object
Implementation Method 2
performing dry etching on the object from the second main surface side to form a groove opening to the second main surface, in the object along each of the plurality of lines to cut
Data Source
AI summary
An object cutting method includes a first step of preparing an object including a single crystal material substrate and a functional device layer provided on a first main surface side, a second step of irradiating the object with laser light to form at least one row of modified regions in the substrate and to form a fracture in the object so as to extend between the at least one row of modified regions and a second main surface of the object, and a third step of performing dry etching on the object from the second main surface side to form a groove opening to the second main surface, in the object. In the third step, the at least one row of modified regions is removed to form an uneven region which has an uneven shape and in which single crystal silicon is exposed, in an inner surface of the groove.