Oblique Die Bonding Imaging for 3D Fiducial Alignment
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Solution Overview
Problem
Conventional die-bonding inspection methods fail to effectively detect micron- or submicron-scale patterns on dies or substrates in the depth direction due to spatial constraints, limiting the detection of microelectronics and die geometry information from a top-down view.
Innovation Solution
Implementing an oblique view imaging system that projects oblique view images onto top and side views using projection matrices, determining fiducial marker positions, and correcting positional errors through image registration algorithms to enhance die bonding inspection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a top-down view imaging system is used for die bonding inspection, then the inspection area can be covered, but the microelectronics and die geometry information in the depth direction cannot be distinctively detected
Solution Approach 1:
The patent transitions from a conventional top-down (2D) view to an oblique view that captures three-dimensional information. By imaging the die at an angle rather than perpendicular to the surface, the system simultaneously obtains both planar alignment data and depth/geometry information, resolving the contradiction between coverage and dimensional information loss.
2Ease of operation
If a top-down view imaging system is used, then the inspection process can be simplified, but the robotic arm motion path occupies the necessary space for accurate imaging
Solution Approach 1:
By changing the imaging angle from top-down to oblique, the system creates spatial clearance that allows robotic arm motion paths without compromising imaging accuracy. The oblique view geometry enables the imaging system to capture necessary information while accommodating the physical constraints of robotic arm movement in the workspace.
3Measurement precision
If oblique view imaging is implemented, then three-dimensional information can be obtained, but image processing complexity increases due to projection transformations
Solution Approach 1:
The patent creates a projected top view image as a computational copy or representation of the actual die surface. By transforming the oblique view image into a projected top view using mathematical models, the system simplifies subsequent processing steps while preserving the enhanced three-dimensional information, thus managing complexity through intelligent image representation.
Solution Approach 2:
The projected top view image serves as an intermediary representation that bridges the oblique view capture and the final inspection requirements. This intermediate processed image format allows the system to leverage three-dimensional information while maintaining compatibility with standard inspection algorithms and fiducial marker detection methods.
Data Source
AI summary
Various examples are provided related to oblique view imaging for die bonding inspection. In one example, a method includes obtaining an oblique view image of a die on an inspection stage in an XOY plane, the image obtained at an angle with respect to the die; generating a top view image in the XOY plane by projecting the oblique view image using a projection matrix based upon top view and oblique view intrinsic parameters; and determining positions of fiducial markers in the projected top view image. In another example, a method includes obtaining an oblique view image of a die on an inspection stage in an XOY plane; generating a side view image in a YOZ plane or an XOZ plane by projecting the oblique view image using a projection matrix based upon side view and oblique view intrinsic parameters; and determining positions of fiducial markers.