Chip Separation Grooves With Plasma-Deposited Masking
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Solution Overview
Problem
The existing methods for plasma etching in chip manufacturing, such as using photoresist or water-soluble protective films, are time-consuming and costly, especially when requiring elaborate laser processing to avoid heat damage to the workpiece.
Innovation Solution
A manufacturing method that forms a mask by supplying a plasmatic deposition gas to the workpiece and uses a cutting blade with a tapered tip to cut along scribe lines, followed by plasma etching, allowing for the use of an inexpensive cutting machine instead of a costly laser processing apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photoresist is used as a mask for plasma etching, then the mask can be formed on the workpiece, but the process requires multiple steps (application, exposure, development) which increases time and effort
Solution Approach 1:
The patent extracts the mask formation process from the complex photoresist steps by using a water-soluble protective film that can be directly patterned with a laser beam, eliminating the need for application, exposure, and development steps while maintaining mask reliability
Solution Approach 2:
The patent replaces the mechanical/chemical photoresist processing system with a laser-based direct writing system that patterns the water-soluble protective film, significantly reducing the number of steps required for mask formation
2Productivity
If laser processing is used to pattern the water-soluble protective film, then the number of processing steps is reduced, but elaborate laser processing with short pulsed laser is needed to avoid heat damage, which increases costs
Solution Approach 1:
The patent changes the laser processing parameters by using a longer pulse duration (10^-6 to 10^-3 seconds) compared to conventional short pulsed lasers, which allows the use of less complex and more cost-effective laser processing equipment while still preventing heat damage to the workpiece
Solution Approach 2:
The patent uses a water-soluble protective film that can be easily removed after serving its masking purpose, replacing the need for complex mask removal processes and allowing the use of simpler, more cost-effective laser processing equipment
3Device complexity
If a cutting blade is used to cut the mask along scribe lines, then the costs are reduced compared to laser processing, but the cut-in depth must be controlled to be small (less than 10 μm) to avoid workpiece damage
Solution Approach 1:
The patent applies local quality by using a cutting blade with a tapered tip shape that concentrates the cutting action at the tip, allowing precise control of cut depth to be less than 10 μm while using a simple, cost-effective cutting blade instead of complex laser equipment
Solution Approach 2:
The patent performs preliminary action by forming the mask with a water-soluble protective film before cutting, which protects the workpiece during the cutting process and allows the use of shallow cuts (less than 10 μm) that can be safely performed with simple cutting blades
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 reduces the costs of plasma etching by simplifying the mask formation process and enabling efficient division of wafers into chips using a standard cutting machine, while maintaining the precision needed to avoid workpiece damage.
Implementation Method 1
a mask forming step of forming a mask by supplying a plasmatic deposition gas to a side of a front surface or a side of a back surface of the workpiece
Implementation Method 2
a cutting step of forming cut grooves, with the mask being removed along the scribe lines, by causing a cutting blade to cut into the workpiece at a predetermined cut-in depth along the scribe lines on the side of a surface on which the mask has been formed
Implementation Method 3
a plasma etching step of removing the workpiece along the scribe lines to divide the workpiece into the chips by applying plasma etching to the workpiece while supplying a plasmatic etching gas to the side of the surface of the workpiece in which the cut grooves have been formed
Data Source
AI summary
Provided is a manufacturing method of a plurality of chips by dividing a workpiece that is defined into a plurality of regions by scribe lines. The manufacturing method includes the following steps of forming a mask by supplying a plasmatic deposition gas to a side of a front surface or a side of a back surface of the workpiece, forming cut grooves, with the mask being removed along the scribe lines, by causing a cutting blade to cut into the workpiece at a predetermined cut-in depth along the scribe lines on a side of the surface on which the mask has been formed, and then removing the workpiece along the scribe lines to divide the workpiece into the chips by applying plasma etching to the workpiece while supplying a plasmatic etching gas to the side of the surface of the workpiece in which the cut grooves have been formed.