Substrate Holding Unit with Adhesion Restriction for Wafer Alignment
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Solution Overview
Problem
Existing substrate bonding techniques face challenges in aligning and bonding semiconductor wafers without damaging them, particularly due to the strong magnetic forces used for adhesion, which can cause misalignment and mechanical stress.
Innovation Solution
A substrate holding unit with a first holding member, joining members, and an adhesion restricting section that allows precise alignment and controlled adhesion of wafers, using electrostatic forces and flat spring components to manage the adhesion force and prevent damage during bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If permanent magnets are used to generate adhesion force for bonding wafers, then the wafers can be held firmly during bonding, but the strong magnetic force causes misalignment of substrates and large shock at the moment of adhesion that may damage the substrates
Solution Approach 1:
The patent applies preliminary action by using a flat spring component to preliminarily hold the wafer on the holding member before bonding. The flat spring maintains a predetermined gap between the wafer and the permanent magnet, allowing alignment to be completed before the strong adhesion force is engaged. This preliminary holding mechanism prevents misalignment that would occur if the strong magnetic force were applied immediately.
Solution Approach 2:
The flat spring component serves as a cushioning element that absorbs and distributes the shock when the wafer approaches the holding member. By maintaining a predetermined gap and providing elastic compliance, the flat spring prevents the large shock that would occur from direct contact between the wafer and the permanent magnet, thereby preventing substrate damage while still enabling firm adhesion.
2Reliability
If permanent magnets exert continuous adhesion force on magnetic bodies, then the wafers can be held securely, but the magnetic force affects the alignment when adjusting relative positions of substrates
Solution Approach 1:
The flat spring component performs preliminary action by establishing a predetermined gap between the wafer and the permanent magnet before bonding begins. During the alignment phase, this gap isolates the wafer from the magnetic force, allowing precise alignment without magnetic interference. Only after alignment is complete does the wafer make contact with the holding member, at which point the adhesion force is engaged to provide secure holding.
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 solution ensures accurate alignment and bonding of semiconductor wafers while minimizing mechanical stress and preventing damage, improving the reliability and efficiency of the bonding process.
Implementation Method 1
using electrostatic forces and flat spring components to manage the adhesion force
Implementation Method 2
using electrostatic forces and flat spring components to manage the adhesion force
Data Source
AI summary
Provided is a substrate holding unit that holds a pair of substrates that are aligned and layered, comprising a first holding member that holds one of the substrates; a plurality of members to be joined that are connected to the first holding member; a second holding member that holds the other of the substrates to face the one of the substrates; a plurality of joining members that exert an adhesion force on the members to be joined and are connected to the second holding member at positions corresponding to positions of the members to be joined; and an adhesion restricting section that restricts the adhesion force until the substrates are aligned.