Wafer Cutting Apparatus with Line Sensor for Stepped Portion
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Solution Overview
Problem
Conventional cutting apparatuses for wafer processing are complex and costly due to the need for multiple sensors to accurately position and measure the wafer and cutting blade, which complicates the edge trimming process and increases the risk of chipping or cracking during grinding.
Innovation Solution
A cutting apparatus featuring a rotatable chuck table, a cutting unit with a spindle-mounted cutting blade, and a line sensor unit that applies a laser beam to detect reflected light, allowing for the calculation of wafer position, height, and stepped portion dimensions, reducing the need for multiple sensors and simplifying the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are mounted to acquire wafer position and stepped portion information, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple measurement functions into a single line sensor system. The line sensor captures both wafer position information and stepped portion dimensional information simultaneously through one integrated component, eliminating the need for multiple separate sensors and reducing system complexity while maintaining measurement precision
Solution Approach 2:
The line sensor is designed to perform multiple functions: measuring wafer position, determining stepped portion width, and measuring stepped portion height. This multi-functional approach allows one sensor to replace what would traditionally require several different sensors, simplifying the overall device structure
2Manufacturing precision
If accurate positional adjustment of cutting blade and wafer is implemented, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the line sensor measures the actual wafer position and stepped portion dimensions, and this information is used to adjust and optimize the cutting process. The measurement results feed back to control the cutting blade positioning, ensuring high precision edge trimming while using a relatively simple adjustment system
Solution Approach 2:
The patent replaces complex mechanical positioning and measurement systems with an optical measurement system using a line sensor. This substitution reduces mechanical complexity while achieving high positioning accuracy through optical detection and computational methods
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 solution enables a simpler, cost-effective cutting apparatus that accurately forms stepped portions on wafers, allowing for precise control of the cutting process and determination of cutting blade wear, thereby preventing chipping or cracking during grinding.
Implementation Method 1
a line sensor unit that applies a laser beam in a band shape elongate in a radial direction of the wafer to a region inclusive of the peripheral portion of the wafer held on the chuck table
Implementation Method 2
detects reflected light of the laser beam reflected on the region
Implementation Method 3
a cutting unit that cuts the peripheral portion of the wafer held on the chuck table from a front surface side by a cutting blade mounted to a spindle, to form on the front surface side of the wafer an annular stepped portion along the peripheral portion
Data Source
AI summary
A cutting apparatus includes a line sensor unit that applies a laser beam in a band shape elongated in a radial direction of a wafer to a region inclusive of a peripheral portion of the wafer held on a chuck table, and detects reflected light, and an information calculation section that calculates the position of the wafer and the height of the front surface of the wafer from the reflected light of the laser beam detected by the line sensor unit in a state in which the chuck table is rotated before the wafer is cut to form a stepped portion, and that calculates the width and the height of the stepped portion from the reflected light of the laser beam detected by the line sensor unit after the wafer is cut to form the stepped portion.