Wafer Mount Side Cleaning via UV Plasma Ozone
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Solution Overview
Problem
The existing wafer processing methods, such as dicing with a blade or laser processing, often result in foreign matter sticking to the mount side of wafers, leading to difficulties in removing tape dust and increasing the likelihood of faulty chip mounting.
Innovation Solution
A wafer processing method that involves dividing the wafer along pre-defined lines, followed by an irradiation step using ultraviolet radiation or plasma to generate ozone and active oxygen, which effectively removes organic matter from the mount side of each chip, reducing the risk of faulty mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dicing with a blade or laser processing is performed on the wafer, then the wafer is divided into individual chips, but foreign matter and tape dust stick to the mount side of the chips
Solution Approach 1:
The patent applies ultraviolet irradiation or plasma treatment to the mount side of chips before mounting to proactively remove organic matter and tape dust. This preliminary cleaning action prevents contamination from affecting subsequent mounting operations, resolving the contradiction between efficient wafer division and prevention of foreign matter adhesion.
Solution Approach 2:
The patent utilizes ozone generated through ultraviolet irradiation or plasma treatment to oxidize and remove organic matter from the mount side. The strong oxidizing action of ozone effectively eliminates tape dust and foreign matter that would otherwise adhere to the mount side during dicing operations, maintaining cleanliness while preserving productivity.
2Ease of manufacture
If protective tape is attached to the front side of the wafer during grinding, then the wafer is held securely, but releasing agent residue increases water repellency of the mount side
Solution Approach 1:
The patent employs ozone treatment through ultraviolet irradiation or plasma to oxidize and remove releasing agent residue from the mount side. This eliminates the water repellency effect caused by the residue, ensuring reliable mounting while maintaining the ease of wafer handling provided by the protective tape during grinding.
Solution Approach 2:
The patent changes the surface energy parameters of the mount side through ultraviolet irradiation or plasma treatment. This process modifies the surface properties to reduce water repellency caused by releasing agent residue, thereby improving mounting reliability without affecting the protective tape's holding function during manufacturing.
3Ease of operation
If spinner cleaning is performed on the wafer, then general cleaning is achieved, but tape dust cannot be completely removed from the mount side
Solution Approach 1:
The patent introduces ozone treatment via ultraviolet irradiation or plasma as a post-cleaning step to oxidize and remove tape dust that spinner cleaning cannot eliminate. This complementary approach maintains the simplicity of spinner cleaning while effectively removing persistent organic contaminants from the mount side.
Solution Approach 2:
The patent combines mechanical cleaning (spinner cleaning) with chemical cleaning (ozone treatment through ultraviolet irradiation or plasma). This composite cleaning approach leverages the strengths of both methods: spinner cleaning for general dust removal and ozone treatment for complete elimination of tape dust, achieving thorough cleaning without complicating the operation.
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 successfully removes foreign matter and tape dust, reducing the occurrence of faulty chip mounting by cleaning the mount side of each chip and minimizing the increased water repellency caused by protective tape residue.
Implementation Method 1
applying ultraviolet radiation or plasma to the mount side of each chip after performing the dividing step, thereby generating ozone and active oxygen
Implementation Method 2
applying ultraviolet radiation or plasma to the mount side of each chip after performing the dividing step, thereby generating ozone and active oxygen
Implementation Method 3
applying ultraviolet radiation or plasma to the mount side of each chip after performing the dividing step, thereby generating ozone and active oxygen
Implementation Method 4
applying ultraviolet radiation or plasma to the mount side of each chip after performing the dividing step, thereby generating ozone and active oxygen
Data Source
AI summary
After performing a dividing step to divide a wafer into individual chips, an irradiation step is performed to apply ultraviolet radiation or plasma to the mount side of each chip, thereby generating ozone and active oxygen, which functions to remove organic matter sticking to the mount side of each chip. Accordingly, it is possible to remove from the mount side of each chip not only foreign matter sticking to the wafer during handling the wafer, but also foreign matter generated in dividing the wafer, so that faulty mounting of each chip can be reduced.