Electronic Package Support Layer for Underfill Flow and Joint Stability

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Solution Overview

Problem

In electronic package structures, small size solders used for electrical connections between wiring and package structures face challenges with underfill coverage and warpage, leading to reduced yield due to insufficient space and potential failure in joining, which complicates the manufacturing process.

Innovation Solution

An electronic package structure design that includes a support layer around electrical contacts with a surface featuring inflection points, allowing for better coverage and protection of small size electrical contacts, and a thermocompression bonding technique to ensure proper jointing with conductive pillars and wiring structures, even in tight spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If small size solders are used to electrically connect the wiring structure and the package structure, then the risk of solder bridging is reduced, but the underfill cannot flow to cover and protect the solders due to insufficient space

Engineering Contradiction:

Improvesolder connection reliabilityVSAvoidspace between wiring structure and package structure

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent introduces a support layer with a three-dimensional structure including recesses and protrusions around the electrical contacts. This adds vertical and lateral dimensions to the support layer geometry, creating channels and spaces that allow underfill to flow around the small solders and reach protective positions, solving the space constraint problem while maintaining solder connection reliability

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The support layer is segmented into multiple functional regions: recesses that accommodate electrical contacts, protrusions that create flow channels for underfill, and varying thickness regions that guide underfill movement. This segmentation allows the support layer to simultaneously provide mechanical support, facilitate underfill flow, and protect small solders

Inventive Principle:

Principle #1Segmentation

2Reliability

If small size solders are used for electrical connection, then solder bridging is prevented, but warpage causes the solders to fail to joint with the package structure or wiring structure, resulting in reduced yield

Engineering Contradiction:

Improvesolder joint integrityVSAvoidmanufacturing yield

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The support layer is positioned around the electrical contacts before the bonding process, providing pre-established mechanical support and positioning. This beforehand cushioning ensures that small solders maintain proper alignment and contact pressure during bonding, preventing joint failures due to warpage while maintaining high manufacturing yield

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Volume of moving object

If the space between wiring structure and package structure is too small, then compact packaging is achieved, but underfill cannot flow to cover and protect the electrical contacts

Engineering Contradiction:

Improvepackage structure compactnessVSAvoidunderfill flowability

Core Design Contradiction:

Volume of moving objectVSEase of manufacture

Solution Approach 1:

The support layer exhibits local quality variations with different thickness regions, recesses, and protrusions positioned at specific locations. The recesses are located where electrical contacts need protection, while protrusions are positioned to create underfill flow channels. This localized structural differentiation enables underfill to navigate the compact space and reach protective positions around electrical contacts

Inventive Principle:

Principle #3Local quality

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 design enhances the yield of electronic package structures by ensuring effective coverage and protection of electrical contacts, improving the jointing process and reducing warpage issues, thereby stabilizing the connections between the wiring and package structures.

Implementation Method 1

The support layer is disposed around the electrical contact and has a surface facing the electrical contact. The surface includes at least one inflection point in a cross-sectional view.

Methodology Applied

Scientific EffectMechanical support:

Implementation Method 2

a thermocompression bonding technique to ensure proper jointing with conductive pillars and wiring structures, even in tight spaces

Methodology Applied

Scientific EffectThermocompression bonding:

Data Source

PatentUS12183683B2Electronic package structure

Publication Date: 2024.12.31 ADVANCED SEMICON ENG INC

AI summary

An electronic package structure includes an electronic structure, a wiring structure, an electrical contact and a support layer. The wiring structure is located over the electronic structure. The electrical contact connects the wiring structure and the electronic structure. The support layer is disposed around the electrical contact and has a surface facing the electrical contact. The surface includes at least one inflection point in a cross-sectional view.