Wafer Processing Resist Film Removal via Chemical Spraying
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Solution Overview
Problem
Existing wafer processing methods, such as plasma dicing, face challenges in removing resist films without damaging devices and incur high costs due to the use of dry etching or chemical fluids, which can harm metal and resin components like polyimide.
Innovation Solution
A wafer processing method involving resist film formation, plasma etching, and subsequent chemical fluid spraying to remove the resist film, followed by grinding to expose the groove on the backside, allowing for the division of the wafer into individual chips without damaging the devices and reducing processing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ashing (dry etching) is used to remove the resist film, then the resist film can be removed, but the devices including metal and resin may be damaged
Solution Approach 1:
The patent changes the chemical parameters of the removal process by using a wet chemical solution instead of plasma ashing. The chemical solution is formulated to selectively remove the resist film while having minimal effect on the device materials, thus changing the removal mechanism from physical/chemical plasma action to controlled chemical dissolution.
Solution Approach 2:
The patent employs a disposable chemical solution that can be applied and then discarded after use. This chemical solution serves its purpose of removing the resist film and is then replaced, avoiding the need for complex equipment like ashing chambers while effectively removing the resist without damaging devices.
2Manufacturing precision
If a dry etching apparatus or chemical fluid is used to remove the resist film, then the resist film can be removed, but the cost and man-hour increase
Solution Approach 1:
The chemical solution is designed to automatically penetrate and remove the resist film through capillary action and chemical dissolution without requiring complex equipment operation. The solution applies itself to the resist film areas and removes it efficiently, reducing the need for sophisticated dry etching apparatus and associated operational costs.
Solution Approach 2:
The patent utilizes hydraulic principles by applying the chemical solution through liquid delivery mechanisms. The solution is pumped or sprayed onto the wafer surface, using fluid dynamics to ensure uniform distribution and penetration into the resist film, achieving effective removal through simple hydraulic action rather than complex pneumatic plasma systems.
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
The method effectively removes the resist film using a simple chemical fluid spraying operation, avoiding damage to the devices and reducing costs by eliminating the need for ashing, thus improving the die strength and processing efficiency while maintaining low costs.
Implementation Method 1
spraying a chemical fluid to the resist film formed on the front side of the wafer, thereby removing the resist film
Implementation Method 2
performing plasma etching to the wafer after performing the resist film forming step, thereby forming a groove on the front side of the wafer along each division line
Implementation Method 3
grinding the back side of the wafer held on the chuck table to reduce the thickness of the wafer to the finished thickness, whereby the groove is exposed to the back side of the wafer
Data Source
AI summary
A wafer processing method includes forming a resist film on the front side of a wafer in an area except division lines, plasma etching the wafer to form a groove on the front side of the wafer along each division line, the groove having a depth greater than a finished thickness, removing the resist film from the front side of the wafer by cleaning, and grinding the back side of the wafer to reduce the thickness of the wafer to the finished thickness, so that the groove is exposed to the back side of the wafer to thereby divide the wafer into individual device chips. In the resist film removing step, a chemical fluid is sprayed to the resist film formed on the front side of the wafer, thereby removing the resist film.