Semiconductor Wafer Cutting Guide Groove Chopper Method
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Solution Overview
Problem
Existing methods for cutting semiconductor wafers and similar workpieces in chopper mode often result in surface chippings and offcut chips from the outer peripheral area, damaging the cutting blade and leading to inefficient processing.
Innovation Solution
A method involving the formation of shallow guide grooves in the workpiece's outer peripheral area and device area, followed by cutting to a predetermined depth along projected dicing lines, which prevents surface chippings and offcut chips by using a chopper cutting mode with a cutting blade that initially cuts a shallow groove and then processes the device area while retracting from the outer peripheral area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chopper cutting mode is used to increase processing rate, then productivity is improved, but surface chippings are produced on the workpiece surface
Solution Approach 1:
A guide groove is formed in advance at the outer peripheral edge of the workpiece before the main cutting operation. This preliminary action creates a prepared path that guides the cutting blade during subsequent chopper cutting, preventing surface chippings while maintaining high processing rates.
Solution Approach 2:
The cutting process is divided into two distinct stages: (1) guide groove formation at the outer peripheral edge, and (2) main device area cutting. This segmentation allows each stage to be optimized independently - the guide groove stage prepares the path to prevent chippings, while the main cutting stage maximizes productivity through chopper mode.
2Productivity
If cutting is performed on the outer peripheral extra area, then complete workpiece division is achieved, but offcut chips are scattered and damage the cutting blade
Solution Approach 1:
Different cutting strategies are applied to different areas of the workpiece: the outer peripheral extra area is processed with a focus on containing offcut chips, while the device area is processed for complete division. The guide groove specifically addresses the outer peripheral area to prevent chip scattering.
Solution Approach 2:
The potentially harmful offcut chips from outer peripheral cutting are converted into a beneficial guiding feature. The guide groove formed during outer peripheral cutting serves as a path that directs subsequent cutting operations, transforming the harmful chip-scattering effect into a useful guidance mechanism for the cutting blade.
3Ease of operation
If bonding of outer periphery is not strong enough, then workpiece handling is easier, but offcut chips are easily scattered during cutting
Solution Approach 1:
The guide groove is formed as a preliminary action at the outer peripheral edge where bonding may be weak. This prepares the cutting path in advance, allowing the cutting blade to follow a predetermined groove rather than forcing through weakly bonded areas, thereby preventing offcut chip scattering while maintaining ease of handling.
Data Source
AI summary
A method of cutting a workpiece includes forming a guide groove to a depth smaller than the predetermined depth in the workpiece, the guide groove extending from the outer peripheral edge to an end portion of the device area, by causing a cutting blade to cut into the workpiece held on the holding surface of the chuck table from an outer peripheral edge of the workpiece along one of the projected dicing lines; and forming a groove to the predetermined depth in the workpiece along the projected dicing line, the groove extending from the device area beyond an opposite end of the device area to a portion of the outer peripheral extra area, after lowering the cutting blade toward and into the guide groove in the device area and then positioning a cutting edge thereof at the predetermined depth.