Semiconductor Pad Grid for Crosstalk Noise Reduction
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Solution Overview
Problem
The increasing demand for high-density signal input/output and power supply connections in semiconductor devices leads to a shortage of pads, causing issues with crosstalk noise and wire contact, which existing technologies like flip chip mounting and wire bonding struggle to address effectively, especially in reducing fabrication costs and maintaining signal integrity.
Innovation Solution
A semiconductor device with pads arranged linearly perpendicular to the peripheral edge of the semiconductor substrate and wire cemented elements on the mounting substrate, where signal pads are positioned farthest from the edge, and power supply and reference voltage pads are arranged closer, with wires bridging them in different loop heights to minimize crosstalk noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of pads is increased to meet high-density signal input/output and power supply connections, then the connection functionality is improved, but the chip area available for circuit integration is reduced
Solution Approach 1:
The patent transitions from traditional peripheral pad arrangement to a two-dimensional grid arrangement of pads on the chip surface. This dimensional change allows pads to be distributed across the chip area rather than confined to the perimeter, significantly increasing the number of available connection points without reducing circuit integration area.
Solution Approach 2:
The pad structure is segmented into multiple types (signal pads, power supply pads, ground pads) arranged in a systematic grid pattern. This segmentation allows different functional pads to be organized efficiently, maximizing connection density while maintaining proper spacing and reducing interference between adjacent pads.
2Ease of manufacture
If wire bonding is used to connect pads, then the assembly process is simplified, but the pad size must be large which reduces the number of pads that can be disposed
Solution Approach 1:
The patent changes the geometric parameters of pad arrangement from peripheral to grid-based, and modifies the connection methodology by introducing wire cemented elements that bridge the grid pads to external connections. This parameter change allows for smaller, more numerous pads while maintaining wire bonding simplicity.
Solution Approach 2:
Wire cemented elements are introduced as intermediary components between the grid pads on the chip and the external mounting substrate. These intermediaries enable compact pad design on the chip while preserving the simplicity of wire bonding assembly processes.
3Speed
If high speed interface is implemented, then the performance is improved, but power supply noise and ground bounce increase requiring more power supply voltage pads and ground pads
Solution Approach 1:
The patent applies local quality by strategically assigning different pad functions to different regions of the grid arrangement. Power supply pads and ground pads are distributed throughout the grid in close proximity to signal pads, creating localized power and ground networks that minimize noise and ground bounce for high-speed signals.
Solution Approach 2:
Multiple ground pads are distributed across the chip surface in the grid arrangement, creating equipotential regions that reduce ground bounce. The close spacing of ground pads throughout the grid maintains consistent ground potential even during high-speed switching operations.
4Reliability
If ground pads for shielding are added to high speed signal lines, then noise resistance is improved, but the number of pads increases further
Solution Approach 1:
The patent merges multiple functions into the grid pad arrangement: signal pads, power supply pads, and ground pads are integrated into a unified two-dimensional structure. Ground pads serve dual purposes as both power/ground connections and shielding elements for adjacent signal pads, eliminating the need for separate shielding pads.
Solution Approach 2:
Each pad in the grid arrangement is designed with multi-functionality. Ground pads provide both electrical connection functions and electromagnetic shielding functions. The grid structure itself provides both signal routing and noise protection, making each pad element serve multiple purposes simultaneously.
Data Source
AI summary
The present invention provides a semiconductor device, including: a semiconductor substrate having a circuit formed thereon; a mounting substrate cemented to a rear face of the semiconductor substrate; a plurality of pads arranged in a linearly juxtaposed relationship with each other in a direction perpendicular to a peripheral edge side of the semiconductor substrate which is nearest to the pads on a main face of the semiconductor substrate and electrically connected to the circuit in a corresponding relationship to a signal, a power supply voltage and a reference signal; a plurality of wires individually cemented at one end thereof to the pads; and a plurality of wire cemented elements formed on the mounting substrate and cemented to the other end of the wires.