Scanning Metrology System for Semiconductor Packaging Alignment
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Solution Overview
Problem
Existing alignment metrology techniques for semiconductor packaging are not fast enough to process thousands of locations on a single substrate, leading to throughput issues and potential alignment errors in hybrid bonding and packaging applications.
Innovation Solution
A fast-scanning alignment metrology system that uses an incoherent light source and a set of optics to transmit an illumination beam through substrates, coupled with an actuator and sensor to move and image substrates in a scanning pattern, allowing for rapid subsurface imaging and alignment data acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a step and repeat process is used to obtain alignment data from each location, then measurement precision can be maintained, but productivity decreases due to the time required to process thousands of locations on a single substrate
Solution Approach 1:
The patent replaces the mechanical step-and-repeat positioning system with a continuous scanning system. Instead of mechanically stepping to discrete locations, the system uses a continuous linear scan mode where the substrate is moved continuously through the measurement beam, eliminating the time losses associated with mechanical positioning and enabling thousands of measurements per hour while maintaining measurement precision through synchronized detection
Solution Approach 2:
The patent implements continuous measurement during substrate scanning. The measurement beam continuously scans across the substrate surface while the substrate moves, allowing measurements to be taken continuously rather than in discrete steps. This continuous action eliminates idle time between measurements and enables high-throughput processing of thousands of locations
2Difficulty of detecting and measuring
If infrared light is used to see through the silicon chip, then measurement capability is improved for subsurface alignment marks, but device complexity increases due to the specialized optics and sensors required
Solution Approach 1:
The patent changes the wavelength parameter of the measurement light to infrared. By using infrared light instead of visible light, the system can penetrate through the silicon chip substrate to access and image alignment marks on the substrate beneath the chip, enabling subsurface measurement capability
Solution Approach 2:
The patent separates the illumination function from the detection function. The illumination source uses infrared light to penetrate the chip, while the detection system captures the transmitted light carrying subsurface alignment information. This segmentation allows optimization of each function independently
3Productivity
If fast scanning is implemented to increase throughput, then productivity improves, but measurement precision may deteriorate due to reduced measurement time at each location
Solution Approach 1:
The patent replaces discrete mechanical positioning with continuous scanning motion. The linear scan mode allows the substrate to move continuously through the measurement beam at high speed while maintaining precise measurement capability through synchronized detection systems that capture data at the correct positions during the continuous motion
Solution Approach 2:
The patent uses periodic sampling during the continuous scan. The detection system synchronizes with the scanning motion to periodically capture measurement data at appropriate intervals during the continuous substrate movement, enabling fast data acquisition while maintaining measurement precision through the periodic sampling strategy
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
The system enables efficient and fast alignment metrology, capable of obtaining thousands of measurements per hour, thereby improving throughput and reducing alignment errors in semiconductor packaging processes.
Implementation Method 1
an incoherent light source configured to transmit an illumination beam through the substrate and the another substrate
Implementation Method 2
a set of optics configured to direct the illumination beam when transmitted through the substrate and the another substrate
Data Source
AI summary
Methods and apparatus for detecting metrology data are provided herein. For example, an apparatus comprises a substrate support configured to support a substrate and another substrate disposed on the substrate, an incoherent light source configured to transmit an illumination beam through the substrate and the another substrate, a set of optics configured to direct the illumination beam when transmitted through the substrate and the another substrate, an actuator operably coupled to the substrate support and configured to move the substrate and another substrate back and forth in a scanning pattern, and a sensor operably coupled to the actuator, synchronized therewith, and configured to receive the illumination beam from the set of optics to obtain subsurface images of the substrate and the another substrate.