Terminal Design with Barrier Layer for Bonding Strength

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Solution Overview

Problem

Existing acceleration sensors face a decrease in bonding strength between terminals and bonding wires due to material diffusion during the production process, leading to potential disconnection and deterioration.

Innovation Solution

The design includes a terminal configuration with a non-overlapping region for reduced material migration, an overlapping region for enhanced electrical connection, and an intermediate layer acting as a barrier to prevent material diffusion, along with a platinum-based wiring system to minimize electric discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If heat is applied during the production process, then the manufacturing process can be completed, but atoms in the foundation layer are diffused into the coating layer and deposited on the surface, decreasing the bonding strength between the terminal and the bonding wire

Engineering Contradiction:

Improveproduction process completionVSAvoidbonding strength

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces a barrier layer as an intermediary between the foundation layer and the coating layer. This barrier layer prevents atom diffusion from the foundation layer to the coating layer during heat application, thereby maintaining bonding strength while allowing the manufacturing process to proceed. The barrier layer acts as a mediator that blocks the harmful diffusion path without interfering with the necessary production steps.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The terminal structure is segmented into multiple distinct layers: foundation layer, barrier layer, and coating layer. This segmentation separates the functions of each layer - the foundation layer provides structural support, the barrier layer prevents diffusion, and the coating layer ensures electrical conductivity and bonding strength. By dividing the terminal into functional segments, the patent resolves the contradiction between heat treatment necessity and bonding strength maintenance.

Inventive Principle:

Principle #1Segmentation

2Strength

If the terminal is constituted by a stacked body of foundation layer and coating layer, then adhesion and electrical properties are improved, but material diffusion occurs during heating, leading to decreased bonding strength

Engineering Contradiction:

Improveadhesion and electrical propertiesVSAvoidbonding strength

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The barrier layer serves as a mediator inserted between the foundation layer and coating layer. It allows the terminal to maintain the beneficial stacked structure for adhesion and electrical properties while preventing the harmful material diffusion that would otherwise occur between the foundation and coating layers during heating processes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The terminal is designed as a composite structure with three distinct material layers, each serving a specific function. The composite nature allows the structure to achieve multiple properties simultaneously: adhesion from the foundation layer, diffusion prevention from the barrier layer, and electrical conductivity with bonding strength from the coating layer, without the materials adversely interacting.

Inventive Principle:

Principle #40Composite materials

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 effectively suppresses the decrease in bonding strength, ensuring reliable electrical connections and reducing the risk of disconnection or deterioration, thereby enhancing the overall reliability of the electronic device.

Implementation Method 1

an intermediate layer disposed between the wiring and the terminal... migration or diffusion of the material (atoms) contained in the wiring into the terminal can be reduced

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

migration or diffusion of the material contained in the wiring into the non-overlapping region can be reduced

Methodology Applied

Scientific EffectMaterial diffusion: Diffusion

Data Source

PatentUS10641788B2Electronic device, electronic device apparatus, electronic apparatus, and moving object

Publication Date: 2020.05.05 SEIKO EPSON CORP

AI summary

An electronic device includes a base body, a functional element disposed on the base body, a wiring disposed on the base body and electrically connected to the functional element, and a terminal disposed on the base body and electrically connected to the wiring, wherein the terminal includes a non-overlapping region which does not overlap with the wiring. Further, the terminal includes an overlapping region which overlaps with the wiring.