Planar Redistribution Interconnects With Copper Bumps to Reduce Warpage

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Solution Overview

Problem

Embedded via pads in redistribution metal structures cause warpage, leading to interconnection failures and electrical yield loss due to high interfacial resistance and formation of electrical opens.

Innovation Solution

A redistribution structure with a manufacturing process that omits embedded via pads, using a redistribution layers-first approach to reduce warpage and enhance electrical characteristics by minimizing seed layer interfaces and intermetallic components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If embedded via pads are used, then redistribution connection is achieved, but warpage causes high interfacial resistance and electrical opens

Engineering Contradiction:

Improveredistribution connectionVSAvoidinterfacial resistance control

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent converts the potential harm of removing embedded via pads (which traditionally provide structural support) into a benefit by using planar metal interconnects with copper bumps that eliminate warpage. The removal of via pads prevents warpage-induced interfacial resistance issues and electrical opens, while the copper bump structure provides robust electrical connection without the harmful warpage effects.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Adaptability or versatility

If traditional embedded via pad structure is used, then redistribution is enabled, but warpage and intermetallic formation reduce electrical yield

Engineering Contradiction:

Improveredistribution structureVSAvoidelectrical yield

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the fundamental parameter of the redistribution structure from three-dimensional embedded via pads to two-dimensional planar metal interconnects with surface-mounted copper bumps. This parameter change eliminates the vertical extent that causes warpage and intermetallic formation, thereby improving electrical yield while maintaining redistribution functionality.

Inventive Principle:

Principle #35Parameter changes

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 effectively reduces warpage and increases electrical yield by eliminating embedded via pads, thereby improving the reliability and performance of semiconductor structures.

Implementation Method 1

forming a first continuous barrier metal layer and a first continuous copper seed layer; forming a first patterned electroplating mask layer and electroplating copper on exposed surfaces

Methodology Applied

Scientific EffectElectroplating: Electroplating

Data Source

PatentUS20250357293A1Redistribution structure with copper bumps on planar metal interconnects

Publication Date: 2025.11.20 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

First redistribution interconnect structures having a respective uniform thickness throughout are formed on a top surface of a first adhesive layer over a first carrier wafer. Redistribution dielectric layers and additional redistribution interconnect structures are formed over the first redistribution interconnect structures to provide at least one redistribution structure. A respective set of one or more semiconductor dies is attached to each of the at least one redistribution structure. The first redistribution interconnect structures are physically exposed by removing the first carrier wafer and the first adhesive layer. Fan-out bump structures are formed on the physically exposed first planar surfaces of the first redistribution interconnect structures.