Semiconductor Cutting via Laser-Reformed Region and Dry Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional cutting methods for semiconductor substrates using expandable tape result in surface roughness, cracks, and defective shapes due to chemical and thermal changes in the tape during dry etching, leading to reduced mechanical strength and unintended cutting, and require lowering etching gas pressure and temperature, limiting the etching rate.
Innovation Solution
A cutting method that forms a reformed region on the semiconductor substrate using a laser beam and performs a dry etching process from the front surface to the rear surface while the substrate is fixed, eliminating the need for an expandable tape and preventing chemical and thermal changes in the tape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a common dry etching process is used on the reformed region, then the etching rate can be maintained, but the expandable tape undergoes chemical and thermal changes causing deformation and unintended cutting
Solution Approach 1:
The patent removes the expandable tape from the processing system entirely. By fixing the workpiece directly to the support member using suction or weight, the tape is extracted from the process, eliminating its harmful chemical and thermal reactions with etching gas while maintaining stable workpiece positioning during dry etching.
Solution Approach 2:
The patent changes the fixing method parameters from mechanical bonding with expandable tape to suction-based or gravity-based fixation. This parameter change eliminates the tape material that causes harmful reactions, allowing standard dry etching conditions (pressure and temperature) to be maintained without causing deformation or unintended cutting.
2Reliability
If the pressure of etching gas and processing temperature are lowered to avoid reaction with expandable tape, then harmful reactions are prevented, but the etching rate becomes impractically low
Solution Approach 1:
By removing the expandable tape from the system and replacing it with direct suction or gravity-based fixation, the patent eliminates the source of harmful chemical and thermal reactions. This allows the etching process to proceed at standard pressure and temperature conditions without compromising process stability, thereby maintaining practical etching rates.
3Ease of operation
If expandable tape is used to hold the workpiece, then the workpiece can be positioned, but surface roughness and cracks occur in chips reducing mechanical strength
Solution Approach 1:
The patent extracts the expandable tape from the workholding system and replaces it with direct fixation to the support member via suction or gravity. This elimination of the tape prevents mechanical damage such as surface roughness and cracks during chip separation, thereby preserving the mechanical strength of the resulting chips while maintaining ease of workpiece positioning.
4Productivity
If expandable tape is used during cutting, then the workpiece can be divided, but by-products adhere inside the device requiring cleaning operations
Solution Approach 1:
By removing the expandable tape from the cutting process and using direct suction or gravity-based fixation instead, the patent eliminates the organic material that reacts with etching gas to form harmful by-products. This extraction prevents adhesion inside the device, maintaining cutting efficiency without creating cleaning requirements.
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 allows precise cutting along intended lines without surface roughness or cracks, maintaining mechanical strength and enabling a practical etching rate without the need to lower etching gas pressure or temperature, thus preventing by-product adherence and extending processing time.
Implementation Method 1
forming a reformed region in the workpiece along the intended cut line, by applying a laser beam while positioning a point of condensation in the workpiece
Implementation Method 2
the workpiece is fixed on a support member at least under its own weight or by suction
Data Source
AI summary
A cutting method includes: forming a reformed region in a workpiece; and after forming the reformed region in the workpiece, cutting the workpiece along an intended cut line. In the cutting the workpiece, a dry etching process is performed from a front surface toward a rear surface of the workpiece while the workpiece is fixed on a support member at least under its own weight or by suction, to form a groove from the front surface to reach the rear surface of the workpiece.