Chip Mounting Calibration for Scheimpflug Image Displacement
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Solution Overview
Problem
The use of a Scheimpflug optical system in mounting apparatuses is prone to image displacement due to temperature changes, leading to errors in determining the target position for semiconductor chip placement, which hinders accurate mounting.
Innovation Solution
A mounting apparatus employing top-view and bottom-view imaging units arranged to satisfy the Scheimpflug condition, with a calibration controller calculating calibration values to correct for image displacement, ensuring accurate placement of semiconductor chips despite temperature fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a Scheimpflug optical system is used for top-view imaging, then the imaging unit can image the work target from an oblique direction, but minute displacements of optical system elements due to temperature changes cause output image displacement in the plane direction, leading to errors in calculating target position
Solution Approach 1:
The patent introduces a calibration index as an intermediary object to establish a reference relationship between the top-view imaging unit and bottom-view imaging unit. By imaging the calibration index with both imaging units and calculating calibration values, the system creates a mediating reference frame that compensates for temperature-induced displacements in the Scheimpflug optical system, thereby maintaining target position accuracy
Solution Approach 2:
The patent applies parameter changes by calculating calibration values that represent the displacement relationship between coordinate systems of different imaging units. These calibration values are dynamically computed based on imaged positions of calibration indices and are used to correct target position calculations, effectively compensating for temperature-induced optical element displacements
2Measurement precision
If a bonding apparatus uses a camera to image the work target from directly above, then the position can be confirmed, but the apparatus takes time to work and has accumulation of movement errors with respect to the work target position
Solution Approach 1:
The patent transitions from a single top-view imaging approach to a multi-dimensional imaging system that includes both top-view imaging units (oblique direction with Scheimpflug condition) and bottom-view imaging units (opposite side). This dimensional expansion allows simultaneous acquisition of position information from multiple perspectives, enabling faster positioning while maintaining accuracy through coordinate calibration
Data Source
AI summary
A mounting apparatus includes a mounting tool; top-view imaging units employing Scheimpflug optical systems for imaging from above a substrate; a bottom-view imaging unit for imaging from below a mounting body held by the mounting tool; a calibration controller calculating calibration values for calibrating a difference between coordinate values calculated based on top-view images and a bottom-view image, based on the top-view images and the bottom-view image of imaging the same calibration index; and a mounting controller recognizing a reference position of the mounting body based on the bottom-view image of the bottom-view imaging unit imaging the mounting body held by the mounting tool, and causing the mounting tool to place and mount the mounting body on the substrate so that the reference position coincides with a target position determined based on the top-view images of the top-view imaging units imaging the substrate and the calibration values.