Roughened Through-Vias for InFo Package Adhesion

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Solution Overview

Problem

In Integrated Fan-Out (InFo) packaging, delamination occurs at interfaces between metal interconnects and dielectric layers due to poor adhesion, affecting the reliability of semiconductor IC packages.

Innovation Solution

The surfaces of conductive through-vias and redistribution lines are roughened using chemical treatments, enhancing the adhesion of surrounding dielectric materials such as PolyBenzOxazole (PBO) or molding materials, thereby improving the reliability of InFo packages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal interconnects are used to connect I/O pads to external electrical connectors, then electrical connectivity is achieved, but delamination occurs at interfaces due to poor adhesion

Engineering Contradiction:

Improveadhesion strengthVSAvoidinterface bonding strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies chemical treatments (such as plasma treatment, oxygen plasma, or chemical etching) to modify the surface properties of metal interconnects. These treatments change the surface energy, roughness, or chemical composition of the metal surface, thereby enhancing adhesion between the metal interconnect and surrounding dielectric layers without altering the bulk properties of the metal

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces adhesion promoter layers or interface layers between the metal interconnects and dielectric materials. These intermediary layers serve as chemical bridges that improve bonding compatibility between dissimilar materials, preventing delamination at the interfaces

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If I/O pads are redistributed to greater area using metal interconnects, then packing density is improved, but delamination occurs reducing package reliability

Engineering Contradiction:

ImproveI/O pad packing densityVSAvoidpackage reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent modifies surface parameters of metal interconnects through chemical or physical treatments to enhance adhesion properties, enabling reliable bonding in high-density interconnect structures where delamination would otherwise occur due to stress concentration

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies adhesion-enhancing treatments to metal interconnect surfaces before depositing dielectric layers or forming bonds. This preliminary surface preparation ensures that subsequent layers adhere properly, preventing delamination issues that would compromise package reliability in high-density configurations

Inventive Principle:

Principle #10Preliminary action

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 roughened surfaces increase adhesion strength by three or more times, leading to better durability and reliability of InFo packages by reducing delamination and improving resistance uniformity.

Implementation Method 1

The surfaces of conductive through-vias and redistribution lines are roughened using chemical treatments

Methodology Applied

Scientific EffectChemical treatment:

Data Source

PatentUS11282793B2Integrated fan-out structure with rugged interconnect

Publication Date: 2022.03.22 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method of forming a package assembly includes forming a first dielectric layer over a carrier substrate; forming a conductive through-via over the first dielectric layer; treating the conductive through-via with a first chemical, thereby roughening surfaces of the conductive through-via; and molding a device die and the conductive through-via in a molding material.