Substrate Bonding Sequence for Void-Free Peripheral Contact
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Solution Overview
Problem
Existing substrate bonding methods face issues with void formation and reduced bonding strength due to insufficient restoring and gravitational forces, leading to gaps between peripheral portions of bonded substrates.
Innovation Solution
A bonding method and device that involves holding substrates with peripheral portions only, bringing central portions into contact while bending one substrate to protrude, and then enlarging the contact area from central to peripheral portions, followed by pressing the peripheral portion of one substrate against the other to ensure full surface contact and prevent voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only peripheral portion is held with vacuum chuck and substrates are brought into contact by restoring force and gravitational force, then the bonding process is simple, but voids occur between peripheral portions and bonding strength decreases
Solution Approach 1:
The patent applies preliminary action by first bringing central portions of substrates into contact while they are in a bent state, then gradually enlarging the contact area from central to peripheral portions before final bonding. This sequential approach ensures that peripheral portions are properly positioned and prevents void formation, thereby improving bonding strength without significantly complicating the overall process
Solution Approach 2:
The patent utilizes dynamics by controlling the bending state of substrates during the bonding process. Substrates are bent to cause central portions to protrude, then gradually returned to a flat state while enlarging the contact area. This dynamic control of substrate shape ensures proper contact and prevents voids, improving bonding reliability
2Device complexity
If peripheral portion is held with vacuum chuck and substrates are bonded by releasing suction, then the device structure is simple, but peripheral portions may be lifted and voids occur
Solution Approach 1:
The patent applies preliminary action by first bringing central portions of substrates into contact while they are in a bent state, then gradually enlarging the contact area from central to peripheral portions before final bonding. This sequential approach ensures that peripheral portions are properly positioned and prevents void formation, thereby improving bonding strength without significantly complicating the overall process
Solution Approach 2:
The patent applies parameter changes by controlling the bending degree of substrates and the gradual enlargement of contact area from central to peripheral portions. By dynamically adjusting these parameters during the bonding process, the method ensures uniform contact across the entire substrate surface and prevents peripheral lifting, thereby improving manufacturing precision
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 effectively prevents voids between substrates and enhances bonding strength by ensuring complete contact over entire surfaces, even when peripheral portions are lifted, thereby improving the reliability of the bonding process.
Implementation Method 1
an annular portion that holds a peripheral portion of a substrate, using a vacuum chuck
Implementation Method 2
due to restoring force and gravitational force acting on the peripheral portion of one of the substrates
Implementation Method 3
due to restoring force and gravitational force acting on the peripheral portion of one of the substrates
Data Source
AI summary
A bonding method includes a substrate holding step of holding substrates (W1, W2), a first contact step of bringing central portions of the substrates (W1, W2) into contact with each other, a second contact step of, enlarging a contact area between the substrates (W1, W2) from central portions toward peripheral portions of the substrates (W1, W2), and a bonding step of, bonding the substrates (W1, W2) to each other by pressing only a peripheral portion of the substrate (W1) against a peripheral portion of the substrate (W2) while the substrates (W1, W2) are in contact with each other over entire bonding surfaces.