Wafer Bonding Alignment Using Interferometer Feedback Control
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Solution Overview
Problem
Existing bonding apparatuses face challenges in accurately aligning semiconductor wafers due to horizontal position deviations during vertical movement, which can lead to misalignment and bonding issues.
Innovation Solution
Incorporation of a laser interferometer system and linear scale for precise position measurement and control of the holders, allowing for accurate alignment and bonding of substrates.
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 horizontal position deviation caused by vertical movement cannot be detected
Solution Approach 1:
A laser interferometer system is introduced as an intermediary measurement device to detect the actual horizontal position of the lower chuck. The laser interferometer measures the horizontal position independently of the mover's commanded position, providing an accurate reference that reveals deviations caused by the wedge-shaped base during vertical movement.
Solution Approach 2:
The system implements feedback control by comparing the laser interferometer's measurement of the lower chuck's actual horizontal position with the commanded position from the linear scale. The controller uses this feedback information to calculate and apply correction amounts to the mover, ensuring accurate alignment despite mechanical deviations.
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 system replaces pure mechanical position control with a hybrid approach combining mechanical movement (mover and wedge base) with optical measurement (laser interferometer) and computational correction. The laser interferometer provides non-contact, high-precision measurement that substitutes for the inadequate mechanical linear scale feedback.
Solution Approach 2:
The controller dynamically changes the position parameters by calculating correction amounts based on the difference between the commanded horizontal position (from linear scale) and the actual horizontal position (from laser interferometer). These correction parameters are applied to the mover to compensate for the horizontal deviation introduced by vertical movement.
3Device complexity
If feedback control based on linear scale is used, then position control is simplified, but horizontal position deviation during vertical movement cannot be corrected
Solution Approach 1:
The laser interferometer system serves multiple functions: it measures the horizontal position of the mover, detects the horizontal deviation of the lower chuck during vertical movement, and provides feedback data for correction. This multi-functional approach enhances precision without proportionally increasing system complexity.
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 proper alignment and bonding of substrates by measuring and adjusting for horizontal deviations, enhancing the accuracy and reliability 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; 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
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 includes 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.