Semiconductor Pad Layout for Inductance Minimization
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Solution Overview
Problem
Current semiconductor device pad layouts with pads arranged in a single row lead to increased inductance, causing power and ground noise issues, which hinder high-speed data transmission, especially in multi-bit components.
Innovation Solution
The implementation of a pad layout with two rows of pads in the central area of the semiconductor chip, where data power source and ground pads are placed in a checker pattern to minimize mutual inductance between lead wires, reducing effective inductance and noise, and allowing for high-speed data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pads are arranged in a single row in the central area, then the device structure is simple and manufacturing is easier, but the inductance increases causing power and ground noise
Solution Approach 1:
The patent transitions from a single-row pad arrangement to a two-row pad arrangement in the central area. This dimensional change allows data power source pads and ground pads to be interleaved in an alternating pattern across two rows, which reduces the loop area and effective inductance of the power and ground paths, thereby suppressing power and ground noise while maintaining manufacturing feasibility.
Solution Approach 2:
The pad layout is segmented into multiple functional groups (data pads, data power source pads, ground pads) arranged in alternating sequence across two rows. This segmentation allows each type of pad to be strategically positioned relative to others, creating multiple small current loops instead of large loops, which reduces inductance and electromagnetic noise.
2Object-affected harmful factors
If data power source and ground pads are placed close together, then the loop area is reduced and noise is minimized, but the layout complexity increases
Solution Approach 1:
The patent employs an asymmetric alternating pattern where data power source pads and ground pads are interleaved in a specific sequence (e.g., DQ0, VDDQ0, DQ1, VDDQ1, DQ2, VSSQ2, DQ3, VSSQ3) rather than symmetric grouping. This asymmetric arrangement optimizes the current path to minimize loop area and inductance while maintaining a regular enough pattern that can be systematically manufactured.
3Productivity
If the number of pads is increased for multi-bit components, then the data transmission capacity increases, but the inductance and noise increase
Solution Approach 1:
For multi-bit components, the patent extends the two-row alternating pattern to accommodate additional pads. Instead of adding pads in a single row which would increase inductance, the alternating pattern across two rows is maintained and expanded, ensuring that each additional data pad is paired with corresponding power and ground pads in close proximity, thus scaling capacity without proportionally increasing noise.
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 configuration reduces power and ground noise, enabling high-speed data transmission by minimizing effective inductance between lead wires for the data power source and ground, thus improving the semiconductor device's performance.
Implementation Method 1
Given pads included in the first and second pad layouts are wire bonded to solder ball lands of the BGA package substrate
Implementation Method 2
data power source and ground pads are placed in a checker pattern to minimize mutual inductance between lead wires, reducing effective inductance and noise
Data Source
AI summary
A semiconductor device is disclosed including a data family pad layout wherein an effort is made to contrive layouts of a power lead wire and a ground lead wire to minimize effective inductance in priority to a length of a lead wire between a pad and a solder ball land of a semiconductor chip. Pad layouts are arrayed in two rows and one unit of the pad layout is configured such that a data power source and ground are adjacent to each other or one data is inserted between the data power source and the ground. Such configurations decrease mutual inductance between the data power sources and increase mutual inductance between the data power source and the ground causing reduction in effective inductance between the data power source and the ground with the resultant minimization of power and ground noises.