Semiconductor External Terminal Grid Layout for Current Distribution

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Solution Overview

Problem

Conventional semiconductor devices with grid array packages do not adequately address current concentration issues, leading to reduced device lifespan as current tends to concentrate in specific external terminals.

Innovation Solution

The semiconductor device employs a grid layout with multiple external terminals arranged in various patterns (such as comb-like, cross, S, T, and L shapes) to distribute current evenly across multiple paths, preventing concentration and enhancing current distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a grid array package is used to mount a large number of external terminals in high density, then the quantity of external terminals is improved, but current concentration occurs in particular external terminals leading to reduced device lifespan

Engineering Contradiction:
Improvequantity of external terminalsVSAvoiddevice lifespan
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by assigning different arrangement patterns to different groups of external terminals based on their current carrying requirements. Terminals handling large currents are arranged in distributed patterns (comb-like, cross, S, T, or L shapes) to prevent concentration, while other terminals may use simpler arrangements. This localized optimization of terminal arrangement patterns resolves the contradiction by ensuring high terminal density overall while protecting specific high-current terminals from concentration effects that would reduce lifespan.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If external terminals are arranged in a conventional grid layout, then manufacturing simplicity is maintained, but current concentration occurs in specific terminals

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcurrent concentration
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent employs asymmetry by replacing the conventional symmetric grid layout with asymmetric arrangement patterns for external terminals. Specifically, comb-like, cross, S, T, and L shaped patterns are used to distribute terminals in ways that break the symmetry of conventional grids. These asymmetric patterns naturally distribute current more evenly across multiple terminals, preventing the concentration effect while remaining manufacturable using standard PCB layout techniques.

Inventive Principle:
Principle #4Asymmetry

3Productivity

If current is allowed to flow through multiple external terminals, then current distribution is improved, but uniform current distribution is difficult to achieve with conventional layouts

Engineering Contradiction:
Improvecurrent distribution efficiencyVSAvoiduniformity of current distribution
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent applies segmentation by dividing external terminals into multiple groups, each handled by a different arrangement pattern (comb-like, cross, S, T, or L shapes). This segmentation allows current to be distributed through multiple separate terminal groups rather than concentrating in a few terminals. Each segmented group is optimized for its specific current load, achieving stable and uniform current distribution across the entire terminal set while maintaining high current handling capability.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3336888B1Semiconductor device
Publication Date: 2020.05.06 ROHM CO LTD
  • EP3336888B1 patent drawingFigure 1
  • EP3336888B1 patent drawingFigure 2
  • EP3336888B1 patent drawingFigure 3

AI summary

This semiconductor device has a plurality of external terminals arranged in an array on a bottom surface of a package. The plurality of external terminals include a first external terminal group for receiving an input of a current from outside the device, and a second external terminal group for outputting a current to the outside of the device. The first external terminal group and the second external terminal group are laid out such that respective arrangement patterns thereof are interlocked with each other. The arrangement patterns may be comb-tooth shaped, cross-shaped, S-shaped, T-shaped, L-shaped, or may have a shape comprising a combination thereof. The plurality of external terminals may be pins, solder balls, or electrode pads.