Wafer Bonding via Plasma Activation and Hydrophilization
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Solution Overview
Problem
Existing joint systems for semiconductor wafers face issues such as wafer breakage and positional displacement due to high pressure, and low joining strength, leading to reduced throughput in wafer joint processing.
Innovation Solution
A joint system that includes a surface activation apparatus to activate the wafer surfaces, a surface hydrophilizing apparatus to form hydroxyls, and a joint apparatus that uses Van der Waals force and hydrogen bonding for strong bonding without the need for physical pressing, along with a transfer-in/out station for efficient processing and handling of multiple wafers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If work rollers press two wafers together to join them, then the wafers are joined together, but the wafers may break due to the load
Solution Approach 1:
The patent replaces the mechanical pressing system with a chemical bonding system. Instead of using work rollers to physically press wafers together, the invention uses plasma treatment to activate wafer surfaces and create chemical bonds (Van der Waals forces and hydrogen bonding) between opposing surfaces. This eliminates mechanical contact and associated damage risks while achieving strong bonding.
Solution Approach 2:
The patent changes the bonding mechanism from mechanical to chemical by modifying surface properties through plasma treatment. The plasma process alters surface energy and chemistry parameters, creating activated surfaces that form strong chemical bonds without requiring mechanical pressure. This parameter change enables bonding without the harmful mechanical loads that cause wafer breakage.
2Strength
If wafers are pressed while deviated from vertical direction, then the wafers are joined together, but positional displacement of the wafers occurs
Solution Approach 1:
The patent eliminates the need for mechanical pressing alignment by replacing the mechanical bonding process with a chemical bonding process. Since plasma-activated surfaces bond through molecular forces rather than mechanical contact, precise vertical alignment is no longer critical. This substitution removes the source of positional displacement problems associated with mechanical pressing.
3Strength
If it takes a lot of time to press the two wafers together to join them, then the wafers are joined together, but the throughput of the wafer joint processing is reduced
Solution Approach 1:
The patent replaces the time-consuming mechanical pressing operation with a rapid plasma treatment and bonding process. Plasma activation occurs quickly, and the subsequent bonding happens automatically when wafers are brought into contact, eliminating the prolonged pressing time required in mechanical systems. This dramatically increases processing throughput while maintaining bond strength.
Solution Approach 2:
The patent skips the lengthy mechanical pressing step entirely by using plasma-activated chemical bonding. The plasma treatment prepares surfaces in seconds, and bonding occurs immediately upon contact without requiring extended pressing time. This rushes through the bonding process efficiently, maximizing throughput.
4Productivity
If the temporary joint is performed by generating the Van der Waals force between the activated front surfaces, then the wafers are temporarily joined, but the joining strength is insufficient
Solution Approach 1:
The patent enhances the bonding strength by modifying surface chemistry parameters through plasma treatment. The plasma process creates highly reactive surface groups and increases surface energy, which strengthens both Van der Waals forces and introduces hydrogen bonding capabilities. This parameter change transforms the bonding mechanism from weak physical adsorption to strong chemical bonding.
Solution Approach 2:
The patent creates a composite bonding mechanism that combines multiple interaction forces: Van der Waals forces from plasma activation and hydrogen bonding from hydroxyl groups on the activated surfaces. This composite approach integrates multiple bonding mechanisms to achieve superior overall bond strength while maintaining rapid processing.
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 the throughput of substrate joint processing by eliminating the risk of wafer breakage and positional displacement, while achieving strong and reliable bonding through Van der Waals forces and hydrogen bonding, thereby improving the efficiency and reliability of wafer joining.
Implementation Method 1
the beam irradiation means activates the front surfaces (joint surfaces) of the wafers to generate the Van der Waals force between the front surfaces of the two wafers
Implementation Method 2
a surface hydrophilizing apparatus hydrophilizing the front surface of the substrate activated in the surface activation apparatus
Implementation Method 3
the hydroxyls on the hydrophilized front surfaces of the substrates are hydrogen-bonded, whereby the substrates can be strongly joined together
Data Source
AI summary
A joint system includes: a transfer-in/out station capable of holding a plurality of substrates or a plurality of superposed substrates, and transferring-in/out the substrates or superposed substrates to/from a processing station; and the processing station performing predetermined processing on the substrates and joining the substrates together. The processing station includes: a surface activation apparatus activating a front surface of the substrate; a surface hydrophilizing apparatus hydrophilizing and cleaning the front surface of the substrate; a joint apparatus joining the substrates together; and a transfer region for transferring the substrate or superposed substrate to the surface activation apparatus, the surface hydrophilizing apparatus, and the joint apparatus.