Wiring Substrate Lead Layout for High-Frequency Impedance Matching
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Solution Overview
Problem
Existing wiring substrates for high-frequency semiconductor devices employing differential signaling lack improved high-frequency properties.
Innovation Solution
A wiring substrate design featuring a substrate with ground and signal conductors, and lead terminals with specific bends and tapered parts to optimize impedance matching and reduce crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lead terminal design is used, then manufacturing is simple, but high-frequency properties are insufficient
Solution Approach 1:
The lead terminal is divided into multiple functional segments: a contacting part for electrical connection, a connecting part with first and second bends for impedance control, and a lead part for external connection. This segmentation allows each part to be optimized for its specific function, improving overall high-frequency performance while maintaining manufacturability.
Solution Approach 2:
The connecting part of the lead terminal incorporates bent portions (first bend and second bend) instead of straight connections. These curved geometries are designed to control impedance and reduce signal reflection, directly addressing the high-frequency property requirements while adding manageable structural complexity.
2Area of moving object
If lead terminals are aligned closely for compact design, then area is reduced, but crosstalk increases
Solution Approach 1:
The connecting part with its bent geometry acts as an intermediary structure between the contacting part and the lead part. This intermediate section is specifically designed to control the distance relationship with adjacent lead terminals, reducing crosstalk while allowing compact overall layout through the bends that can be positioned optimally.
3Reliability
If simple lead terminal geometry is used, then manufacturing is easier, but impedance matching is poor
Solution Approach 1:
The lead terminal's geometric parameters (bend angles, bend radii, segment lengths) are specifically designed and controlled to achieve target impedance values. By adjusting these parameters during the design stage, optimal impedance matching is achieved while the overall structure remains compatible with standard manufacturing processes for lead terminals.
Data Source
AI summary
A wiring substrate includes a substrate having a first surface, a first lead terminal in contact with a ground conductor on the first surface, and a second lead terminal in contact with a signal conductor on the first surface and aligned with the first lead terminal. The first lead terminal includes a first end, a contacting part, a connecting part, a lead part and a second end. The contacting part includes the first end and is in contact with the ground conductor. The connecting part includes a first bend, a short-distance part and a second bend. The first bend is away from the first end across the contacting part. The second bend is closer to the second end than the first bend. The short-distance part has a shorter distance to the second lead terminal than the contacting part in plan view toward the first surface.