X-Ray Wafer Singulation for Irregular Die Spacing
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Solution Overview
Problem
Current semiconductor wafer singulation processes face challenges due to inconsistent die spacing and the presence of infrared inhibiting layers, which obscure alignment features, leading to inaccurate imaging and cutting, especially in cases where metallized layers or mold material obscure the necessary features.
Innovation Solution
The implementation of an X-ray imaging system that can penetrate infrared inhibiting layers to detect alignment features, coupled with a cutting system that uses a laser or water jet to dynamically adjust cutting paths, allowing for precise singulation of dies with irregular spacings and orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If infrared imaging is used to detect alignment features, then imaging can be performed, but infrared inhibiting layers (metallized layers, mold material) obscure the features leading to inaccurate detection
Solution Approach 1:
The patent introduces an X-ray imaging system as an intermediary detection method that penetrates through the infrared-inhibiting metallized layers and mold material to directly visualize alignment features and die structures. This mediator (X-ray) bypasses the harmful infrared-blocking layers that prevent accurate infrared imaging, enabling precise detection of alignment features without requiring modification to the wafer structure.
Solution Approach 2:
The patent changes the detection parameter from infrared radiation to X-ray radiation. By transitioning to a different electromagnetic spectrum range (X-ray instead of infrared), the system overcomes the obstruction caused by metallized layers and mold material that are transparent to X-rays but blocking to infrared, thereby achieving accurate alignment feature detection.
2Manufacturing precision
If fixed cutting paths are used for wafer singulation, then cutting process is simple, but inconsistent die spacing leads to inaccurate cutting and die damage
Solution Approach 1:
The patent implements dynamic cutting path adjustment where the cutting system transitions from fixed, pre-programmed paths to real-time adaptive paths based on actual die positions detected by X-ray imaging. The cutting tool coordinates its motion dynamically to follow the actual locations of dies and alignment features, accommodating spacing variations and misalignments while maintaining high cutting accuracy.
Solution Approach 2:
The system incorporates feedback by using X-ray imaging to detect actual die positions and alignment feature locations, then using this information to adjust and optimize the cutting paths in real-time. This closed-loop feedback mechanism ensures that cutting paths adapt to manufacturing variations in die spacing and orientation, preventing die damage while maintaining precision.
3Measurement precision
If extensive pre-processing is performed to expose alignment features, then accurate imaging is achieved, but process time and complexity increase
Solution Approach 1:
The patent uses X-ray imaging as an intermediary detection method that requires no pre-processing to expose alignment features. Unlike infrared imaging that requires removing or modifying infrared-inhibiting layers, X-rays penetrate these layers directly, eliminating time-consuming pre-processing steps while maintaining accurate alignment feature visualization.
Solution Approach 2:
The patent extracts the detection capability from the visible/infrared spectrum and moves it to the X-ray spectrum, where the harmful infrared-inhibiting layers become transparent. This extraction of the detection function to a different physical domain eliminates the need for pre-processing steps designed to make alignment features visible to infrared imaging.
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 enables accurate and efficient singulation of semiconductor dies with variable pitches and orientations, reducing die damage and increasing yield by accounting for irregular spacings and misalignments, while avoiding the need for extensive pre-processing to expose alignment features.
Implementation Method 1
The implementation of an X-ray imaging system that can penetrate infrared inhibiting layers to detect alignment features
Implementation Method 2
coupled with a cutting system that uses a laser or water jet to dynamically adjust cutting paths
Data Source
AI summary
Methods and systems for imaging and cutting semiconductor wafers and other microelectronic device substrates are disclosed herein. In one embodiment, a system for singulating microelectronic devices from a substrate includes an X-ray imaging system having an X-ray source spaced apart from an X-ray detector. The X-ray source can emit a beam of X-rays through the substrate and onto the X-ray detector, and X-ray detector can generate an X-ray image of at least a portion of the substrate. A method in accordance with another embodiment includes detecting spacing information for irregularly spaced dies of a semiconductor workpiece. The method can further include automatically controlling a process for singulating the dies of the semiconductor workpiece, based at least in part on the spacing information. For example, individual dies can be singulated from a workpiece via non-straight line cuts and/or multiple cutter passes.