SAW Device Assembly Segmented Power Wiring for Pre-Dicing Sorting
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Solution Overview
Problem
Surface acoustic wave devices with a WLP structure face challenges in distinguishing between non-defective and defective products before they are cut into individual devices, as all wirings are connected to the power supply, causing electrical shorts and preventing characterization of electrical characteristics.
Innovation Solution
A surface acoustic wave device assembly with a collective board featuring separate circuit portions and power supply wiring configurations allows for the sorting of non-defective and defective products by using distinct connections and under-bump metal layers, enabling easy identification and separation of surface acoustic wave devices and evaluation elements with the same or similar electrical and physical configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all wirings are connected to the power supply wiring for electrolytic plating, then under-bump metals can be formed efficiently, but ground terminals and hot terminals become electrically short-circuited preventing electrical characteristic examination
Solution Approach 1:
The power supply wiring is segmented into multiple independent wiring groups, where each group serves specific terminals (hot terminals or ground terminals) separately. This segmentation prevents electrical short-circuits between terminals while maintaining efficient electrolytic plating formation of under-bump metals.
2Ease of manufacture
If all wirings are connected to the power supply wiring, then electrolytic plating can be performed uniformly, but non-defective and defective products cannot be sorted before dicing
Solution Approach 1:
Electrical characteristic examination is performed preliminarily on the collective board before dicing into individual devices. The segmented wiring configuration enables this early detection, allowing non-defective products to be identified and sorted before the dicing process, reducing waste and improving manufacturing efficiency.
3Reliability
If separate wiring connections are implemented for hot and ground terminals, then electrical characteristic examination becomes possible, but wiring complexity increases
Solution Approach 1:
The segmented power supply wiring groups serve multiple functions: they enable electrical characteristic examination by preventing short-circuits, facilitate efficient electrolytic plating formation, and allow preliminary product sorting. This multi-functionality reduces the need for additional separate wiring systems.
4Difficulty of detecting and measuring
If evaluation elements are included on the collective board, then product sorting is enabled, but the board layout and manufacturing complexity increase
Solution Approach 1:
Evaluation elements are merged with the surface acoustic wave devices on the same collective board, sharing the segmented power supply wiring infrastructure. This integration enables product sorting functionality without requiring completely separate evaluation boards or additional manufacturing processes.
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
Enables effective sorting of non-defective and defective products before division, improving the manufacturing process and reducing costs by ensuring only non-defective products proceed to subsequent processes, while stabilizing the posture and reducing thickness variations during substrate division.
Implementation Method 1
a collective board that is defined by a piezoelectric body
Implementation Method 2
a plurality of first circuit portions that are provided on the collective board and respectively include interdigital transducer (IDT) electrodes
Data Source
AI summary
A surface acoustic wave device assembly includes a collective board, first circuit portions provided on the collective board and respectively including first hot terminals and first ground terminals, a second circuit portion provided on the collective board and including second hot terminals and second ground terminals, and a power supply wiring provided on the collective board so as to surround the periphery of the first circuit portions and the second circuit portion. The first circuit portions include surface acoustic wave devices defining band pass filters. The second circuit portion defines a band pass filter. The first ground terminals and first hot terminals, and the second ground terminal are connected to the power supply wiring, the second hot terminals are not connected to the power supply wiring, and pass bands of the surface acoustic wave devices and a pass band of the band pass filter defined by the second circuit portion are the same or substantially the same.