Ball Grid Array Common Terminal Design

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Solution Overview

Problem

Conventional ball grid arrays do not effectively reduce the number of solder balls required when a single semiconductor chip is mounted on an interposer, leading to a less compact design.

Innovation Solution

A ball grid array design where at least one power supply or ground terminal acts as a common ball terminal, connecting to multiple pads of the semiconductor chip through wirings, reducing the total number of ball terminals needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If each pad of the semiconductor chip is connected to a separate ball terminal, then the electrical connection is simple and reliable, but the total number of ball terminals increases making the ball grid array less compact

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidnumber of ball terminals

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Multiple pads that require the same potential (power supply pads or ground pads) are merged to connect to a single common ball terminal through the interposer wiring, reducing the total number of ball terminals while maintaining reliable electrical connections for all connected pads

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

A single ball terminal serves multiple functions by providing a common connection point for multiple pads that share the same electrical potential requirement, making the ball terminal universal for both power supply or both ground connections

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Quantity of substance

If multiple pads are connected to a common ball terminal, then the number of ball terminals is reduced making the array compact, but noise interference may occur between power supply and ground terminals

Engineering Contradiction:

Improvenumber of ball terminalsVSAvoidnoise interference

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The power supply pads and ground pads are segmented into separate groups, with power supply pads connecting to common power ball terminals and ground pads connecting to common ground ball terminals, preventing noise interference between different potential groups while still reducing the total number of ball terminals within each group

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the interposer provide different electrical characteristics - power supply regions maintain high potential stability while ground regions provide low impedance noise sinks, ensuring that each local area maintains its functional quality even when multiple pads share common ball terminals

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS7586186B2Ball grid array

Publication Date: 2009.09.08 DENSO CORP

AI summary

A ball grid array includes: a semiconductor chip having multiple pads; and an interposer for mounting the semiconductor chip on a first surface. The interposer includes multiple wirings on the first surface and multiple ball terminals on a second surface opposite to the first surface. Each wiring is connected to a corresponding pad of the semiconductor chip, and is electrically connected to a corresponding ball terminal. At least one of ball terminals providing a power supply terminal or a ground terminal provides a common ball terminal for connecting to at least two of the pads of the semiconductor chip through two wirings.