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 of the object.
Innovation Solution
The method involves forming an etching protection layer on one main surface of a single crystal silicon substrate, irradiating it with laser light to create modified regions and fractures, and then performing dry etching from the opposite main surface to form a groove, allowing for precise cutting of semiconductor chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser light is irradiated to form modified regions and fractures extend to both main surfaces, then cutting depth is improved, but incomplete cutting and remaining unprocessed portions occur
Solution Approach 1:
The cutting process is divided into two distinct stages: first forming modified regions and initial fractures through laser irradiation, then performing dry etching to complete the groove formation. This segmentation allows each stage to optimize for its specific function, ensuring complete and reliable cutting without remaining unprocessed portions.
Solution Approach 2:
The laser irradiation step performs preliminary action by creating modified regions and initial fractures that serve as starting points for the subsequent dry etching process. This preliminary modification makes the material more susceptible to complete removal during etching, ensuring final cutting completeness.
2Manufacturing precision
If dry etching is performed from the second main surface side to form narrow and deep grooves, then chip separation precision is improved, but process complexity increases
Solution Approach 1:
The patent replaces traditional mechanical cutting methods with a combination of laser irradiation and dry etching. This substitution enables the formation of narrow and deep grooves with high precision that would be difficult to achieve mechanically, while the process steps remain relatively simple and controllable.
Solution Approach 2:
The dry etching process utilizes controlled parameter changes (etching depth, groove width, etching rate) to achieve precise chip separation. By adjusting etching parameters, the process forms grooves with specific dimensions that enable clean separation while maintaining process simplicity through standard semiconductor manufacturing techniques.
3Productivity
If extension film is extended to cut the object into semiconductor chips, then chip separation is achieved, but fractures reaching both surfaces cause incomplete cutting
Solution Approach 1:
The laser irradiation creates preliminary modified regions and initial fractures that serve as controlled starting points. When the extension film is subsequently extended, these pre-formed structures guide the separation process, ensuring that chips are cleanly separated without leaving incomplete portions, thus achieving both high productivity and precision.
Solution Approach 2:
The extension film acts as an intermediary tool that, when extended, utilizes the pre-formed modified regions and fractures to achieve clean chip separation. The combination of the intermediary film and the pre-prepared fracture paths ensures complete cutting while maintaining efficient batch processing capability.
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 reliable cutting of semiconductor chips by forming a narrow and deep groove, preventing unnecessary influence from the etching protection layer and maintaining the substrate's strength, while facilitating efficient chip separation and pickup.
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, in a state in which the etching protection layer is formed on the second main surface, 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 to be processed including a single crystal silicon substrate and a functional device layer provided on a first main surface side and forming an etching protection layer on a second main surface of the object; a second step of irradiating the object with laser light to form at least one row of modified regions in the single crystal silicon substrate and to form a fracture in the object so as to extend between the at least one row of modified regions and a surface of the etching protection layer; and a third step of performing dry etching on the object from the second main surface side, in a state in which the etching protection layer is formed on the second main surface, to form a groove opening to the second main surface.