Wafer Division Monitoring via Particle Counting Below Dicing Tape
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Solution Overview
Problem
Existing wafer dividing methods fail to effectively check whether modified layers have been properly formed after division, especially when particles are not deposited on the wafer surface.
Innovation Solution
A wafer dividing method and apparatus that form modified layers using a laser beam, position the wafer with a frame and dicing tape, and use a particle counter in a dust collection path to determine the formation of modified layers by counting scattered particles during division.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the wafer is divided in a downwardly directed state to prevent particles from being deposited on the front surface, then particle deposition on the wafer surface is reduced, but the ability to check whether modified layers have been properly formed is lost
Solution Approach 1:
A particle counter is introduced as an intermediary device to detect particles in the dust collection path. This mediator enables indirect measurement of modified layer formation quality without requiring particles to deposit on the wafer surface, thus resolving the contradiction between preventing particle deposition and maintaining measurement capability
Solution Approach 2:
The traditional mechanical inspection method (visual or physical checking of deposited particles on the wafer surface) is replaced with an optical/electronic detection system (particle counter). This substitution allows for non-contact, indirect measurement of particle generation, enabling quality verification without particles needing to deposit on the wafer
2Productivity
If particles are scattered from modified layers during division, then division process occurs, but particle quality of device chips is lowered
Solution Approach 1:
The particles scattered during division, which were previously considered harmful contaminants, are converted into useful measurement indicators. By counting these particles with a particle counter, the invention transforms a harmful byproduct into a beneficial diagnostic tool for verifying modified layer formation, thus resolving the contradiction between completing division and maintaining chip quality
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
Enables determination of proper modified layer formation even when particles are not deposited on the wafer surface, ensuring accurate division and quality of device chips.
Implementation Method 1
applying a laser beam of such a wavelength as to be transmitted through the wafer to the wafer while positioning a condensing point of the laser beam to an inside of the wafer corresponding to the streets, to form modified layers
Implementation Method 2
counting particles scattered at the time of division of the wafer by a particle counter disposed in a dust collection path set directly below the wafer
Data Source
AI summary
A wafer dividing method includes forming modified layers which will be starting points of division, integrally attaching an annular frame and the wafer together through a dicing tape, directing the wafer downward and expanding the dicing tape to divide, into individual device chips, the wafer along the modified layers formed along the streets, counting particles scattered at the time of division of the wafer by a particle counter disposed in a dust collection path set directly below the wafer, and determining, on the basis of the number of the particles, whether or not the modified layers have been properly formed, at the time of carrying out the dividing step.