Semiconductor Cutting Method Using Periodic Dry Etching and Pressure Reduction
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Solution Overview
Problem
Conventional dry etching processes for cutting semiconductor substrates result in grooves with small widths, making it difficult for etching gas to enter, leading to a low rate of groove formation.
Innovation Solution
A cutting method involving the formation of a reformed region using a laser beam, followed by a first dry etching process from the front surface to the rear surface, then a pressure-reducing process, and a second dry etching process under reduced pressure to enhance groove formation along the intended cut line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a common dry etching process is used to form a groove along the intended cut line, then the groove width is reduced (enabling microfabrication), but the etching gas cannot easily enter the groove, resulting in a low groove formation rate
Solution Approach 1:
The patent applies periodic action by alternating between dry etching processes and pressure-reducing processes. The dry etching process etches the groove while the pressure-reducing process removes accumulated reaction by-products by reducing chamber pressure. This periodic cycling maintains high etching gas supply to the groove opening, sustaining a high groove formation rate throughout the deep etching process
Solution Approach 2:
The patent changes the pressure parameter periodically during the etching process. By reducing pressure after initial etching steps, the system removes reaction by-products that would otherwise block etching gas from entering the groove. This parameter change (pressure reduction) enables continuous high-rate etching gas supply to reach the groove interior, maintaining high productivity throughout the process
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 significantly increases the rate of groove formation along the intended cut line by allowing etching gas to readily enter the groove, improving the etching process efficiency.
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
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 3
a first dry etching process is performed from a front surface toward a rear surface of the workpiece
Implementation Method 4
a first pressure-reducing process is performed in which the workpiece is placed under an atmosphere of reduced pressure as compared to pressure during the first dry etching process
Data Source
AI summary
A cutting method includes: forming a reformed region in a workpiece; and after forming the reformed region in the workpiece, forming a groove in the workpiece along an intended cut line. In the forming a groove, a first dry etching process is performed from a front surface toward a rear surface of the workpiece. After the first dry etching process, a first pressure-reducing process is performed in which the workpiece is placed under an atmosphere of reduced pressure as compared to pressure during the first dry etching process. After the first pressure-reducing process, a second dry etching process is performed from the front surface toward the rear surface of the workpiece.