Stopper Layer Roughness for Embedded Substrate Delamination

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Solution Overview

Problem

The reliability of electronic component embedded substrates is compromised due to differences in thermal expansion coefficients between low CTE die materials and high CTE organic composite materials, leading to interface delamination issues, especially after thermal cycles or humidity tests.

Innovation Solution

A stopper layer with fine roughness is formed on the exposed surface of the substrate, increasing surface area and mechanical bonding, and a modularized structure is introduced with surface mounted components to enhance adhesion between heterogeneous materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a stopper layer is inserted into organic composite material to form a cavity for embedding electronic components, then component embedding capability is improved, but interface delamination occurs due to difference in coefficients of thermal expansion

Engineering Contradiction:

Improvecomponent embedding capabilityVSAvoidinterface bonding reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by creating a rough surface structure specifically at the interface between the stopper layer and adhesive material. The roughness is localized to the contact surface where bonding occurs, while other regions maintain their original properties. This localized surface modification enhances adhesion without affecting the overall thermal expansion characteristics of the materials.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by pre-forming a rough surface structure on the stopper layer before applying the adhesive material. This pre-prepared rough surface provides enhanced mechanical interlocking capability from the outset, ensuring improved bonding reliability before the actual assembly process occurs.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If fine roughness is formed on the exposed surface of the stopper layer to increase surface area, then adhesion between heterogeneous materials is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveadhesion strengthVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical surface treatment processes with a chemical etching process. Instead of using mechanical methods like grinding or blasting to create roughness, the invention uses chemical etching agents to form the desired surface topology, thereby reducing manufacturing complexity while achieving the same adhesion enhancement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent applies parameter changes by controlling the roughness parameters (Ra and Rz values) within specific ranges to optimize adhesion while maintaining manufacturability. By defining specific parameter ranges rather than arbitrary values, the invention balances performance improvement with manufacturing feasibility.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the surface roughness of the stopper layer is increased to enhance mechanical bonding, then bonding reliability is improved, but surface area requirement increases

Engineering Contradiction:

Improvebonding reliabilityVSAvoidsurface area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent transitions from considering only the two-dimensional surface area to incorporating the third dimension by creating vertical roughness features. This dimensional change allows the bonding interface to extend into the depth direction, increasing the effective bonding area without proportionally increasing the planar surface area footprint.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

Improved adhesion between the stopper layer and adhesive materials reduces interface delamination, enhancing bonding reliability and allowing for miniaturization and modularization of electronic component embedded substrates.

Implementation Method 1

a surface roughness of one surface of the stopper layer in the first region may be greater than a surface roughness of one surface of the stopper layer in the second region

Methodology Applied

Scientific EffectPhysical adhesion: Adhesive

Data Source

PatentUS11640952B2Electronic component embedded substrate

Publication Date: 2023.05.02 SAMSUNG ELECTRO MECHANICS CO LTD

AI summary

An electronic component embedded substrate includes a core structure including a first insulating body and core wiring layers and having a cavity and having a stopper layer disposed as a bottom surface; an electronic component disposed in the cavity and attached to the stopper layer; and a build-up structure including a second insulating body covering at least a portion each of the core structure and the electronic component and filling at least a portion of the cavity, and build-up wiring layers wherein the stopper layer has a first region in which a portion of one surface is exposed from the first insulating body and a second region in which the other portion of one surface is covered with the first insulating body, and a surface roughness of one surface of the stopper layer in the first region is greater than that of the stopper layer in the second region.