Through-Via Package Structure for Stress-Balanced Interconnects

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing semiconductor package structures face issues with stress accumulation and the formation of cracks or voids during the packaging process, particularly due to mismatched coefficients of thermal expansion between conductive and passivation layers, and unbalanced stress distribution caused by the alignment of through via structures and conductive connectors.

Innovation Solution

The package structure incorporates a conductive structure with a first via portion directly connected to a through via structure and a second via portion with one end connected to the substrate, where the second via portion is used to balance stress and prevent cracking by being directly below the conductive connector, and the formation of a specific ratio of the second via portion to the conductive connector area reduces stress without affecting routing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If through via structures are aligned with conductive connectors, then routing efficiency is improved, but stress concentration and crack formation increase due to unbalanced stress distribution

Engineering Contradiction:

Improverouting efficiencyVSAvoidstress distribution balance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The conductive structure is divided into two separate via portions: a first via portion that aligns with the through via structure for routing efficiency, and a second via portion that is offset from the through via structure to balance stress distribution. This segmentation allows each via portion to serve a specific function, resolving the contradiction between routing efficiency and stress balance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the conductive structure are designed with different via configurations. The first via portion is positioned to optimize electrical routing, while the second via portion is positioned specifically to address stress concentration issues. This local differentiation allows the structure to simultaneously achieve good routing efficiency and balanced stress distribution in different areas.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If conductive and passivation layers are used with mismatched coefficients of thermal expansion, then manufacturing flexibility is improved, but stress accumulation and void formation increase during packaging

Engineering Contradiction:

Improvematerial selection flexibilityVSAvoidstress accumulation

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention changes the geometric parameters of the conductive structure by introducing a second via portion with specific dimensions and positioning. This via portion is designed with a cross-sectional area ratio between 0.1 to 0.5 relative to the conductive connector, which optimizes stress distribution and prevents void formation while maintaining manufacturing flexibility.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If a single via structure is used for electrical connection, then device complexity is reduced, but stress concentration and crack formation increase

Engineering Contradiction:

Improveconductive structure configurationVSAvoidcrack prevention

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The conductive structure is segmented into two via portions with distinct functions. The first via portion provides the primary electrical connection, while the second via portion serves as a stress-relief feature. This segmentation increases structural reliability without significantly complicating the overall device design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second via portion acts as an intermediary element between the first via portion and the surrounding passivation layer. It mediates the stress distribution by providing an additional conductive path that relieves concentration stresses, thereby preventing crack formation while maintaining electrical functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 configuration effectively reduces the formation of cracks and voids, enhancing the reliability and yield of the package structure by balancing stress distribution and minimizing material mismatch-induced failures.

Implementation Method 1

the second via portion is used to balance stress and prevent cracking by being directly below the conductive connector

Methodology Applied

Scientific EffectStress distribution:

Implementation Method 2

mismatched coefficients of thermal expansion between conductive and passivation layers

Methodology Applied

Scientific EffectCoefficient of thermal expansion mismatch: Thermal Expansion

Data Source

PatentUS11923310B2Package structure including through via structures

Publication Date: 2024.03.05 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A package structure and method for forming the same are provided. The package structure includes a first through via structure formed in a substrate and a semiconductor die formed below the first through via structure. The package structure further includes a conductive structure formed in a passivation layer over the substrate. The conductive structure includes a first via portion and a second via portion, the first via portion is directly over the first through via structure, and there is no conductive material directly below and in direct contact with the second via portion.