Backmetal Jet Ablation for Non-Rectangular Die Singulation
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Solution Overview
Problem
Conventional methods for forming semiconductor packages often result in chips and cracks on the die surface during sawing, leading to reliability issues and limited shape options for die perimeters, as they rely on mechanical sawing which is not effective for non-square or non-rectangular shapes.
Innovation Solution
The method involves forming notches on the semiconductor substrate using etching techniques, applying an organic material, thinning the substrate, and jet ablating the backmetal to singulate the packages, allowing for the formation of packages with varied die shapes and reduced surface defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical sawing is used to singulate semiconductor packages, then the singulation process is simple and fast, but chips and cracks occur on the die surface and only rectangular shapes are possible
Solution Approach 1:
The patent replaces the mechanical sawing system with a jet ablation system that uses high-velocity fluid jets to remove material. This substitution eliminates mechanical contact with the die surface, preventing chips and cracks while enabling complex shape singulation through programmable jet paths
Solution Approach 2:
The patent changes the physical state and properties of the cutting medium by using controlled pressure and composition of the jet fluid. By adjusting pressure parameters and fluid composition, the system achieves precise material removal without mechanical stress, resolving the contradiction between precision and simplicity
2Adaptability or versatility
If mechanical sawing is used for singulation, then the process is straightforward, but non-rectangular die shapes cannot be formed
Solution Approach 1:
The patent implements a dynamic singulation system where the jet ablation paths are programmable and adaptable. The system can dynamically adjust jet trajectories, speeds, and patterns to create various die shapes including non-rectangular configurations, transforming a static mechanical process into a flexible programmable one
Solution Approach 2:
The patent adds computational and control dimensions to the singulation process. By introducing programmable jet paths and multi-axis movement control, the system transitions from simple linear sawing to complex three-dimensional material removal patterns, enabling versatile shape creation
3Manufacturing precision
If jet ablation is used to remove backmetal, then precise material removal is achieved, but the process takes longer than conventional methods
Solution Approach 1:
The patent segments the backmetal removal process into multiple targeted jet ablation zones. By dividing the removal operation into discrete regions that can be processed sequentially or in parallel, the system achieves both precision in each zone and improved overall throughput through efficient process orchestration
Solution Approach 2:
The patent employs periodic pulsed jet ablation rather than continuous material removal. The pulsed action allows for controlled material removal with cooling intervals, preventing heat buildup while maintaining precision, and the rhythmic operation optimizes productivity by balancing removal rate with process control
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 enhances the reliability of semiconductor packages by eliminating cracks and chips, enabling the production of packages with non-rectangular die shapes and improving the overall structural integrity and connectivity.
Implementation Method 1
removing one or more portions of the backmetal through jet ablating the second side of the semiconductor substrate
Data Source
AI summary
Various implementations of a method of forming a semiconductor package may include forming a plurality of notches into the first side of a semiconductor substrate; forming an organic material over the first side of the semiconductor substrate and the plurality of notches; thinning a second side of the semiconductor substrate opposite the first side one of to or into the plurality of notches; stress relief etching the second side of the semiconductor substrate; applying a backmetal over the second side of the semiconductor substrate; removing one or more portions of the backmetal through jet ablating the second side of the semiconductor substrate; and singulating the semiconductor substrate through the permanent coating material into a plurality of semiconductor packages.