Multilayer Conductive Posts for Void-Free Electronic Packaging

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Solution Overview

Problem

Conventional semiconductor packages face issues such as void formation due to size variation and unevenness in lasered holes, leading to poor yield, and conductive posts made of single materials suffer from thermal expansion mismatch and poor electrical properties in high temperature or high frequency environments.

Innovation Solution

The use of multilayer composite materials for conductive posts, comprising layers of cobalt, copper, and optionally a dielectric fill material, formed through existing processes and machinery to ensure uniform dimensions and flat side walls, preventing voids and improving CTE matching and electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional electroplated copper post method is used, then manufacturing process is simple, but voids are easily formed due to size variation and unevenness of lasered holes

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidconductive post uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by forming a planarization layer before forming the conductive posts. This planarization layer pre-compensates for the unevenness of the lasered holes, providing a uniform base surface for subsequent electroplating. This preliminary intervention ensures that the conductive posts formed later have uniform dimensions and flat side walls, preventing void formation while maintaining the simplicity of the electroplating process.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If single material conductive posts are used, then manufacturing process is simple, but CTE mismatch and poor electrical properties occur in high temperature or high frequency environments

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidelectrical properties and CTE matching

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies composite materials by constructing conductive posts with multiple material layers: a copper layer for electrical conductivity, a cobalt layer for CTE matching and barrier properties, and optionally a dielectric fill material for structural stability. This multi-layer composite structure simultaneously achieves good electrical properties, matched CTE, and prevention of copper migration, resolving the reliability issues of single-material posts while extending the manufacturing process in a controlled manner.

Inventive Principle:

Principle #40Composite materials

3Reliability

If multilayer composite materials are used for conductive posts, then CTE matching and electrical conductivity are improved, but manufacturing process complexity increases

Engineering Contradiction:

Improveelectrical properties and CTE matchingVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses preliminary action by forming a planarization layer before depositing the multilayer composite structure. This preliminary step creates a uniform surface that simplifies subsequent layer deposition, ensuring consistent thickness and composition of the copper, cobalt, and dielectric layers. This approach reduces manufacturing variability and makes the complex multilayer process more controllable and repeatable.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies parameter changes by carefully controlling the thickness parameters of each layer in the composite structure. The copper layer thickness is optimized for electrical conductivity, the cobalt layer thickness is controlled for CTE matching and barrier function, and the dielectric fill material thickness is adjusted for structural stability. By optimizing these parameters, the patent achieves high reliability while keeping the manufacturing process manageable through precise but not excessive complexity.

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

This approach enhances product yield by preventing void formation and improving electrical conductivity, while maintaining compatibility with existing manufacturing infrastructure without significant cost increases.

Implementation Method 1

the conductive posts 13 are formed by conventional electroplated copper post method

Methodology Applied

Scientific EffectElectroplating: Electroplating

Implementation Method 2

the conductive posts 13 made of a single material are prone to have mismatch in coefficient of thermal expansion (CTE)

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20260006717A1Electronic package and manufacturing method thereof

Publication Date: 2026.01.01 SILICONWARE PRECISION IND CO LTD

AI summary

An electronic package is provided. A plurality of conductive posts with multilayer composite materials and at least one electronic component are disposed on a carrier structure. An encapsulation layer covers the at least one electronic component and the plurality of conductive posts. A circuit structure is disposed on the encapsulation layer and is electrically connected to the plurality of conductive posts. Therefore, the multilayer composite materials for the conductive posts achieve CTE (coefficient of thermal expansion) matching, improve electrical conductivity, and prevent copper diffusion in high temperature or high frequency working environments. A manufacturing method of the electronic package is also provided.