3D Optical Gap Metrology for Semiconductor Package Assembly
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Solution Overview
Problem
Current methods for measuring chip gaps in semiconductor packaging, such as visual inspection and advanced optical microscopy, are inadequate for small devices, and 2D/3D X-ray systems are slow and potentially damaging, lacking the accuracy and speed needed for continuous quality control.
Innovation Solution
A metrology system utilizing non-contact, 3-dimensional profilers to measure thicknesses of individual elements and assembled components, generating gap measurement maps by calculating differences in thickness measurements, enabling rapid, precise, and non-destructive inline inspection during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If 2D/3D X-ray systems are used for gap measurements, then defect detection capability is improved, but measurement speed deteriorates (several minutes per view) and device safety worsens (damage to DRAMS and safety concerns)
Solution Approach 1:
The patent replaces the mechanical X-ray measurement system with an optical measurement system using cameras and image processing. This substitution maintains defect detection capability while dramatically improving measurement speed to suitable for continuous assembly processes and eliminating device damage and safety concerns associated with X-ray systems
Solution Approach 2:
The patent creates optical copies (images) of the assembly for measurement purposes. By capturing images with cameras and processing them to extract gap measurements, the system avoids direct physical or radiological interaction with the device, thereby preventing damage while maintaining measurement accuracy
2Measurement precision
If 2D/3D X-ray systems are used for gap measurements, then defect detection capability is improved, but device safety and operational safety deteriorate
Solution Approach 1:
The patent replaces the harmful X-ray measurement system with a benign optical measurement system. The optical cameras and image processing techniques provide equivalent defect detection capability without exposing devices to ionizing radiation, thereby eliminating device damage and safety concerns
Solution Approach 2:
The patent introduces optical images as an intermediary between the measurement system and the device. By measuring gaps through optical copies rather than direct X-ray interaction, the system eliminates harmful effects while maintaining measurement capability
3Measurement precision
If advanced optical microscopy techniques are used for inspection, then measurement precision is improved, but applicability to small semiconductor devices deteriorates
Solution Approach 1:
The patent transitions from 2D optical microscopy to a stereo vision system that captures depth information in the third dimension. By using two cameras at different positions and processing their images to extract 3D coordinates, the system achieves both high precision for small features and adaptability for various semiconductor device sizes and configurations
4Ease of operation
If visual inspection techniques are used for gap analysis, then ease of operation is improved, but measurement precision deteriorates for extremely small semiconductor devices
Solution Approach 1:
The patent creates detailed optical copies of the assembly through stereo imaging. By processing these images to extract precise 3D coordinates of component surfaces, the system maintains the ease of optical inspection while achieving the measurement precision required for small semiconductor devices through automated image analysis
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 approach provides accurate, high-speed, and non-destructive chip gap measurements, suitable for high bandwidth memory products, improving quality control and reducing defects like solder ball bridging, while being compatible with memory die inspection and not affected by warpage.
Implementation Method 1
determining a first thickness measurement for the first element, a second thickness measurement for the second element, and an assembled thickness measurement for the assembled element
Data Source
AI summary
The present disclosure is directed to a metrology system having 3-dimensional sensors for thickness measurements of semiconductor elements, and methods for taking the thickness measurements. In an aspect, the 3-dimensional sensor may be a single or dual 3-dimensional profiler that may scan across the top and bottom surfaces of an element to obtain a thickness measurement. In another aspect, the method may be used to measure a gap between elements that have assembled together.