Semiconductor Package Dielectric Barrier for Copper Post Grinding

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Solution Overview

Problem

During semiconductor packaging, the exposure of copper posts to grinding causes diffusion into the epoxy molding compound, leading to short circuits and topography issues due to the copper diffusing into the surrounding material.

Innovation Solution

A dielectric layer is introduced between the protective mold structure and conductive material to prevent copper diffusion, enhancing semiconductor package reliability by maintaining separation during grinding and reducing stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the copper post is exposed to grinding during the molding process, then the EMC layer can be ground back to the desired level, but copper diffuses into the surrounding EMC material causing short circuits and topography issues

Engineering Contradiction:

ImproveEMC layer grinding precisionVSAvoidpackage reliability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

A dielectric layer is introduced as an intermediary barrier between the copper post and the EMC material. This dielectric layer prevents copper diffusion into the EMC while allowing the EMC to be ground to the desired level, thus resolving the contradiction between manufacturing precision and package reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the copper post is ground to connect the EMC layer to the underlying silicon die circuitry, then electrical connection is achieved, but copper diffusion causes short circuits

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidcopper diffusion

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The dielectric layer serves as a mediator that allows the copper post to maintain its electrical connection function while preventing the harmful copper diffusion into the surrounding EMC material.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful diffusion property of copper is extracted or isolated from the system by introducing the dielectric layer, which blocks the diffusion path while preserving the electrical connection function of the copper post.

Inventive Principle:

Principle #2Taking out (Extraction)

3Shape

If the EMC layer is ground back after molding, then the desired topography is achieved, but copper diffusion creates topography issues

Engineering Contradiction:

ImproveEMC layer topographyVSAvoidcopper diffusion-induced topography defects

Core Design Contradiction:

ShapeVSObject-generated harmful factors

Solution Approach 1:

The dielectric layer acts as a protective intermediary that enables the EMC layer to be ground to the desired shape without the harmful side effect of copper diffusion creating topography defects.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12438086B2Semiconductor package and method of forming the same with dielectric layer disposed between protective mold structure and stepped structure of side portion of semiconductor die

Publication Date: 2025.10.07 CHENGDU ESWIN SYST IC CO LTD

AI summary

In an embodiment, a semiconductor package is disclosed that includes a conductive material disposed in electrical contact with a semiconductor die, a protective mold structure disposed on the semiconductor die and a dielectric layer disposed on the semiconductor die and between the protective mold structure and the conductive material.