2D-3D Solder Inspection for Warped Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current solder inspection techniques for semiconductor integrated circuit devices face challenges in accurately measuring the height and volume of solder on warped substrates, requiring multiple PSDs, manual setting of height measurement references, and lack of efficient 2D image storage for visual confirmation, leading to increased costs and reduced efficiency.
Innovation Solution
A 2D-3D inspection method that uses a CMOS area camera to measure solder height and volume by adjusting image pickup ranges and exposure times to account for substrate warping, automatically setting height references, and storing 2D images of defective areas for visual confirmation, reducing manual data preparation and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Z-axis mechanism is added to vertically actuate a laser and PSD to follow the warped surface of the substrate, then measurement accuracy of solder height is improved, but device complexity and cost increase
Solution Approach 1:
The patent transitions from 2D inspection to 3D inspection by adding height measurement capability. A laser beam is projected onto the solder surface and the reflected light is detected by a PSD (Position Sensitive Detector) to measure the height of the solder in the vertical dimension, enabling accurate measurement on warped substrates without requiring mechanical Z-axis adjustment mechanisms.
Solution Approach 2:
The patent replaces the conventional mechanical Z-axis actuation mechanism with an optical measurement system. Instead of physically moving the laser and PSD vertically to follow substrate warping, the system uses laser light reflection and PSD position detection to optically measure height variations, eliminating the need for mechanical adjustment mechanisms.
2Measurement precision
If two PSDs are mounted to detect light reflected from both printed solder and substrate surface, then measurement accuracy is improved, but cost increases
Solution Approach 1:
The patent makes a single PSD perform multiple functions by using it in sequence for both substrate surface detection and solder surface detection. The PSD first detects the substrate surface to establish a reference plane, then detects the solder surface to measure height, eliminating the need for separate detection devices for each surface type.
Solution Approach 2:
The patent employs periodic detection actions where the laser and PSD are sequentially positioned to detect different surfaces. The system alternates between detecting the substrate surface and the solder surface at different time points, using temporal separation to achieve what would otherwise require simultaneous multi-device detection.
3Measurement precision
If manual setting of height measurement reference is required, then measurement accuracy can be maintained, but productivity decreases
Solution Approach 1:
The inspection system automatically performs height reference measurement by detecting the substrate surface and establishing a reference plane without requiring manual intervention. The system self-calibrates by using the detected substrate surface as the zero-height reference, enabling automated height measurement of solder relative to the substrate.
Solution Approach 2:
The patent performs preliminary detection of the substrate surface to establish the height reference plane before proceeding to solder height measurement. This preliminary action automatically sets the measurement baseline, eliminating the need for manual reference setting and enabling subsequent automated inspection operations.
4Reliability
If 2D inspection is performed before 3D inspection, then inspection thoroughness is improved, but time consumption increases
Solution Approach 1:
The patent merges 2D and 3D inspection functions into a single integrated inspection process. The same laser and PSD system used for 3D height measurement also provides 2D positional information, combining both inspection dimensions into one simultaneous operation rather than requiring separate sequential inspection steps.
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 method enables efficient and cost-effective 2D-3D inspection, allowing for accurate measurement and visual confirmation of solder defects, improving overall inspection efficiency and reducing operational costs by automating data preparation and storage.
Implementation Method 1
a laser beam is projected onto a solder surface to thereby measure a height of the printed solder
Data Source
AI summary
In the fabrication of a semiconductor integrated circuit device, a 2D-3D inspection technique for solder printed on a substrate is provided which permits easy preparation of data and easy visual confirmation of a defective portion. In a substrate inspecting step, first, a 3D inspection is performed, followed by execution of 2D inspection, whereby a 2D picked-up image of the portion of a pad determined to be defective can be displayed on a larger scale simultaneously with the end of inspection, thereby providing an environment for efficient visual confirmation of the defect. Further, by subjecting a raw substrate to measurement at the time of preparing inspection data, a relation between an original height measurement reference generated automatically by the inspection system and the height of a pad upper surface is checked, whereby it is possible to measure the height and volume of printed solder based on the pad upper surface.