Conductive Stub Geometry for Full EMI Shield Coverage

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Solution Overview

Problem

The assembly process for embedded die packages with EMI protection can cause conductive material to be unprotected by the EMI shield, negatively affecting the EMI characteristics of the package.

Innovation Solution

The implementation of modified conductive stubs with thinner edge portions on the bottom layer of the substrate, ensuring they do not come into contact with adhesive tape during assembly, thereby maintaining full coverage by the EMI shield and enhancing EMI characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conductive stubs have uniform thickness throughout, then manufacturing is simpler, but edge portions contact adhesive tape during assembly causing EMI shield exposure and degraded EMI characteristics

Engineering Contradiction:

ImproveEMI characteristicsVSAvoidconductive stub structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The conductive stub is designed with non-uniform thickness where the edge portion has a reduced thickness compared to the central portion. This local variation ensures that the edge portion does not contact the adhesive tape during assembly, preventing EMI shield exposure and maintaining EMI characteristics, while the central portion maintains sufficient thickness for electrical connectivity.

Inventive Principle:

Principle #3Local quality

2Reliability

If conductive stubs are positioned close to substrate edges, then EMI shield coverage is improved, but they contact adhesive tape during assembly causing exposure

Engineering Contradiction:

ImproveEMI shield coverageVSAvoidassembly process

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The edge portion of the conductive stub has a reduced thickness that allows it to be positioned close to the substrate edge for improved EMI shield coverage while preventing contact with the adhesive tape during assembly, thus avoiding exposure and maintaining both coverage and assembly ease.

Inventive Principle:

Principle #3Local quality

3Stability of the object's composition

If adhesive tape is applied broadly during assembly, then mechanical stability is improved, but conductive stubs contact the tape causing EMI shield exposure

Engineering Contradiction:

Improvemechanical stabilityVSAvoidEMI characteristics

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The reduced thickness of the edge portion allows the adhesive tape to be applied broadly for mechanical stability without causing contact with the conductive stub, thereby preventing EMI shield exposure and maintaining EMI characteristics while achieving the desired mechanical stability.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12482761B2Semiconductor device package having improved conductive stub coverage

Publication Date: 2025.11.25 SANDISK TECHNOLOGIES LLC

AI summary

A semiconductor device package includes a multi-layer substrate including a bottom layer and a top layer. One or more dies are mounted on and electrically coupled to the top layer of the substrate. An electromagnetic interference (EMI) shield encapsulates the substrate and the semiconductor dies. A first plurality of conductive stubs is positioned around edges of the top layer of the substrate. Each of the conductive stubs includes an edge portion having a first thickness and in contact with the EMI shield. A second plurality of conductive stubs is positioned around edges of the bottom layer of the substrate. Each of the second plurality of conductive stubs includes an edge portion having a second thickness less than the first thickness and in contact with the EMI shield.