Wafer Bonding Alignment Using Laser Interferometer Feedback
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Solution Overview
Problem
The existing bonding apparatuses face challenges in accurately aligning semiconductor wafers due to horizontal position deviations during vertical movement, which can lead to misalignment and improper bonding.
Innovation Solution
Incorporation of a laser interferometer system and linear scales to measure and control the position of holders, enabling precise adjustment and alignment of substrates during bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a linear scale is used to measure the position of the mover in the horizontal direction, then the position can be measured, but the position deviation cannot be detected when the lower chuck is moved in the vertical direction
Solution Approach 1:
A laser interferometer is introduced as an intermediary measurement device to detect the horizontal position of the lower chuck directly, independent of the mover's vertical movement. This intermediary measurement system resolves the limitation of the linear scale by providing a separate, reliable position detection path that is not affected by the mechanical coupling between vertical and horizontal movements.
Solution Approach 2:
The mechanical measurement system (linear scale attached to the mover) is supplemented with an optical measurement system (laser interferometer) that measures the lower chuck's position directly. This substitution replaces the indirect mechanical measurement with a direct optical measurement, eliminating the error caused by mechanical coupling in the wedge-shaped base structure.
2Speed
If the lower chuck is moved in the vertical direction using a wedge-shaped base, then vertical movement is achieved, but horizontal position deviation occurs
Solution Approach 1:
The laser interferometer provides real-time feedback on the horizontal position of the lower chuck during vertical movement. This feedback enables the control system to detect and correct horizontal position deviations, ensuring that the bonding process maintains high precision even while achieving efficient vertical movement through the wedge-shaped base mechanism.
3Ease of operation
If feedback control is performed based on linear scale measurement, then position adjustment is possible, but position deviation during vertical movement cannot be corrected
Solution Approach 1:
The laser interferometer serves as an intermediary measurement system that directly monitors the lower chuck's horizontal position, providing accurate data for feedback control. This intermediary measurement path bypasses the errors introduced by the wedge-shaped base mechanism, enabling precise position correction that maintains bonding alignment accuracy while preserving ease of 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
Ensures accurate and reliable bonding of substrates by correcting horizontal deviations, enhancing the precision of the bonding process.
Implementation Method 1
a laser interferometer system configured to measure a position of the first holder or the second holder which is moved by the mover
Implementation Method 2
a first holder configured to vacuum-exhaust a first substrate to attract and hold the first substrate on a bottom surface thereof
Implementation Method 3
the wafers are bonded in the bonding apparatus by a Van der Waals force and a hydrogen bond (intermolecular force)
Implementation Method 4
the wafers are bonded in the bonding apparatus by a Van der Waals force and a hydrogen bond (intermolecular force)
Data Source
AI summary
A bonding apparatus configured to bond substrates comprises a first holder configured to vacuum-exhaust a first substrate to attract and hold the first substrate on a bottom surface thereof; a second holder disposed under the first holder, and configured to vacuum-exhaust a second substrate to attract and hold the second substrate on a top surface thereof; a mover configured to move the first holder and the second holder relatively in a horizontal direction; a laser interferometer system configured to measure a position of the first holder or the second holder which is moved by the mover; a linear scale configured to measure a position of the mover; and a controller configured to control the mover based on a measurement result of the laser interferometer system and a measurement result of the liner scale.