Wafer Division via Plasma Etching and Resist Film Control
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Solution Overview
Problem
The existing methods for wafer dicing, such as cutting with a high-speed blade or plasma etching, result in small chips on the cutting surface, reducing die strength, and the use of resist films in plasma etching complicates the process, leading to reduced productivity due to the need for ashing.
Innovation Solution
A method where a resist film is coated on the back of the wafer excluding street areas, and plasma etching is used to divide the wafer, with the resist film's thickness adjusted to be etched simultaneously, eliminating the need for ashing and improving productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a resist film is used in plasma etching for wafer dicing, then the etching process can be performed, but the resist film must be removed by ashing, reducing productivity
Solution Approach 1:
The patent extracts the harmful resist film completely by making it etchable, so that the resist film is removed together with the street material during plasma etching, eliminating the need for separate ashing processes
Solution Approach 2:
The patent merges the resist film removal process with the street etching process by designing the resist film to be etchable, so both the street material and resist film are removed in a single plasma etching operation
2Productivity
If a high-speed cutting blade is used for wafer dicing, then the cutting process is fast, but small chips appear on the cutting surface, reducing die strength
Solution Approach 1:
The patent replaces the mechanical cutting blade system with a plasma etching system, which uses plasma to erode the street material without mechanical contact, thereby eliminating chip formation while maintaining processing efficiency
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 approach enhances die strength by removing stress from the devices and simplifies the dicing process, eliminating the need for ashing and reducing chipping, thereby improving productivity and maintaining device quality.
Implementation Method 1
a division step of performing plasma etching from a side of the back of the wafer coated with the resist film, so that the areas corresponding to the streets of the wafer are etched to divide the wafer into the individual devices
Data Source
AI summary
A method of dividing and separating a wafer having a plurality of devices formed on its front surface, which are separated by streets. The method includes applying a resist film coating to a portion of the back surface of the wafer other than an area corresponding to the streets, and plasma etching the area of the back surface corresponding to the streets to divide the wafer into a plurality of individual devices. The thickness of the resist film coating is adjusted in the coating operation to allow the resist film to be completely removed during the plasma etching.