Sintered Via Interconnects for Flat Semiconductor Wiring Surfaces

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Solution Overview

Problem

Existing semiconductor devices face issues with the flatness of the upper surface of the wiring layer for external connections, which can lead to voids in solder and decreased connection reliability.

Innovation Solution

A semiconductor device design that includes a wiring substrate with an insulating layer and a wiring layer, where the semiconductor element is fixed with its first electrode facing the substrate, and a first via interconnect formed of a sintering material of metal fills a through hole to electrically connect the wiring pattern and the electrode, ensuring a flat upper surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal plating is used to fill the through hole and form the wiring layer, then electrical connection is achieved, but the upper surface of the wiring layer becomes non-flat with depressions

Engineering Contradiction:

Improveconnection reliabilityVSAvoidflatness of upper surface

Core Design Contradiction:

ReliabilityVSShape

Solution Approach 1:

The patent changes the material parameter from traditional metal plating to sintering material (conductive paste containing metal particles). This material parameter change enables the wiring layer to be formed with a flat upper surface while maintaining electrical connectivity, resolving the contradiction between connection reliability and surface flatness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the electrochemical plating process with a sintering process. Instead of using electroplating to deposit metal, the invention uses sintering of conductive paste to form the wiring layer, which inherently produces a flat surface without the depressions caused by plating over via holes

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If a depression is formed in the upper surface of the wiring layer, then the through hole filling is complete, but voids are generated in solder during bonding

Engineering Contradiction:

Improvevia filling completenessVSAvoidsolder connection quality

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

By changing from metal plating to sintering material, the patent eliminates the depression formation issue. The sintering process allows the conductive paste to be applied in a controlled manner and sintered to form a flat wiring layer surface, preventing solder voids while ensuring complete via filling

Inventive Principle:

Principle #35Parameter changes

3Reliability

If traditional metal plating process is used, then electrical connection is established, but the process complexity and manufacturing difficulty increase

Engineering Contradiction:

Improveelectrical connectionVSAvoidmanufacturing process simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the complex electroplating process (requiring seed layers, electrochemical equipment, and multiple steps) with a simpler sintering process. The conductive paste is applied directly and sintered in a single step, significantly simplifying the manufacturing process while maintaining reliable electrical connection

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses conductive paste as a disposable material that is applied and then sintered. This eliminates the need for expensive and complex plating equipment, making the process more economical and easier to manufacture

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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

The solution improves the flatness of the upper surface of the wiring layer, reducing the likelihood of voids in solder and enhancing the reliability of external connections, while also providing better heat dissipation and reduced stress due to the use of sintering materials.

Implementation Method 1

The first via interconnect is formed of a sintering material of metal

Methodology Applied

Scientific EffectSintering: Sintering

Data Source

PatentUS20250079325A1Semiconductor device

Publication Date: 2025.03.06 SHINKO ELECTRIC IND CO LTD

AI summary

A semiconductor device includes a wiring substrate and a semiconductor element. The wiring substrate includes an insulating layer and a wiring layer. The semiconductor element includes a first electrode and is fixed to the wiring substrate with the first electrode facing the wiring substrate. The wiring layer includes a first wiring pattern on a surface of the insulating layer on the opposite side from the semiconductor element. The wiring layer further includes a first via interconnect. The first via interconnect is formed of a sintering material of metal and fills in a first through hole piercing through the first wiring pattern and the insulating layer to expose the first electrode. The first via interconnect electrically connects the first wiring pattern and the first electrode.