Electronic Component Terminal Electrode Structure for Wire Bonding and Solder Mounting

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Solution Overview

Problem

Existing electronic components face challenges in allowing wire bonding with base metals on one surface and solder mounting on another, while maintaining electrical characteristics and preventing infiltration of plating solutions that can deteriorate performance.

Innovation Solution

The electronic component features a first terminal electrode with a sintered metal layer and a base metal plating layer on one surface for wire bonding, and a second terminal electrode with a sintered metal layer, a base metal plating layer, and a solder layer including Sn and a higher melting point metal like Sb on the other surface for solder mounting, which improves bonding strength and suppresses plating solution infiltration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If wire bonding with base metal is used on the first principal surface, then cost is reduced, but bonding strength may be insufficient without proper plating

Engineering Contradiction:

ImprovecostVSAvoidbonding strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The terminal electrode uses a composite structure combining sintered metal layer (for cost-effectiveness and base metal compatibility) with plating layer (for enhanced bonding strength). This composite approach allows wire bonding with base metals at reduced cost while the plating layer ensures sufficient bonding strength.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The plating layer acts as an intermediary between the sintered metal layer and the wire. It provides a surface that enhances bonding strength for wire attachment while the underlying sintered metal layer maintains cost-effectiveness by using base metals.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If plating is applied to both terminal electrodes, then wire bonding and solder mounting are enabled, but plating solution may infiltrate and deteriorate electrical characteristics

Engineering Contradiction:

Improvemounting method compatibilityVSAvoidelectrical characteristics

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The terminal electrodes are segmented into different structures: the first terminal electrode has a sintered metal layer with plating for wire bonding, while the second terminal electrode has sintered metal layer with plating and solder layer for solder mounting. This segmentation allows different mounting methods on different surfaces while managing plating solution infiltration risks.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different local qualities are applied to different terminal electrodes based on their mounting requirements. The first terminal electrode is optimized for wire bonding with base metal wire, while the second is optimized for solder mounting with appropriate plating and solder layer, preventing plating solution infiltration in both cases.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If solder layer is added to the second terminal electrode, then solder mounting is enabled, but manufacturing complexity increases

Engineering Contradiction:

Improvesolder mounting capabilityVSAvoidelectrode structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The electrode structure is segmented with the solder layer added only to the second terminal electrode where solder mounting is required. This selective addition enables solder mounting capability without unnecessarily complicating the first terminal electrode structure used for wire bonding.

Inventive Principle:

Principle #1Segmentation

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 enables cost-effective wire bonding with base metals and solder mounting, enhancing bonding strength and reducing the risk of electrical characteristic deterioration, while maintaining the stability of the component's sintered ceramic material and preventing cracks.

Implementation Method 1

infiltration of a plating solution into the element body is suppressed by the first sintered metal layer

Methodology Applied

Scientific EffectPhysical barrier (sintered metal layer):

Implementation Method 2

wire bonding mounting using the wire including the base metal is possible on the first principal surface side

Methodology Applied

Scientific EffectMetal bonding:

Implementation Method 3

a solder layer formed on the second plating layer. The second plating layer includes the base metal. The solder layer includes Sn, and a metal having a higher melting point than the melting point of Sn

Methodology Applied

Scientific EffectSoldering: Soldering

Data Source

PatentUS9984822B2Electronic component

Publication Date: 2018.05.29 TDK CORP

AI summary

An element body includes a first principal surface and a second principal surface opposing each other in a first direction. A first terminal electrode is disposed on the first principal surface side of the element body. A second terminal electrode is disposed on the second principal surface side of the element body. The first terminal electrode includes a first sintered metal layer formed on the first principal surface; and a first plating layer formed on the first sintered metal layer and including base metal. The second terminal electrode includes a second sintered metal layer formed on the second principal surface, a second plating layer formed on the second sintered metal layer and including base metal, and a solder layer formed on the second plating layer and including Sn and a metal having a higher melting point than the melting point of Sn.