Substrate Recess Channels for Void-Free Semiconductor Underfill

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Semiconductor packages face issues such as delamination, cracking, and moisture-induced defects due to voids in the underfill material between the interposer and package substrate, which affect mechanical integrity and yield.

Innovation Solution

Incorporating recesses in the package substrate surface and channels in their bottom surfaces to accommodate semiconductor devices, ensuring a minimum gap for adequate underfill material flow, enhancing structural coupling and reducing defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If semiconductor devices are mounted directly on the package substrate surface, then device integration is achieved, but voids form in the underfill material causing delamination and cracking

Engineering Contradiction:

Improvedevice integrationVSAvoidmechanical integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The package substrate surface is segmented into recess regions and non-recess regions, creating localized depressions beneath each semiconductor device. This segmentation allows the underfill material to properly distribute and bond around the devices without forming voids, while maintaining direct mounting integration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The recess regions are formed only in specific locations beneath semiconductor devices, creating local structural modifications rather than uniform changes across the entire substrate. This local quality change enables adequate underfill flow and bonding precisely where needed, improving mechanical integrity without affecting overall device integration.

Inventive Principle:

Principle #3Local quality

2Reliability

If the package substrate surface is modified with recesses, then underfill material flow is improved and defects reduced, but manufacturing complexity increases

Engineering Contradiction:

Improvestructural coupling integrityVSAvoidsubstrate structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The recess regions are formed in the package substrate before the semiconductor devices are mounted. This preliminary action prepares the substrate surface in advance to receive the devices and underfill material, ensuring proper bonding without requiring complex post-assembly modifications.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The substrate surface geometry is modified by changing the local depth parameter to create recess regions. This parameter change from a flat surface to a stepped surface with controlled depth enables improved underfill flow and bonding while maintaining a relatively simple overall structure.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250357358A1Semiconductor package with substrate recess and methods for forming the same

Publication Date: 2025.11.20 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Semiconductor packages and methods of fabricating semiconductor packages include a package substrate having a recess formed in a surface of the package substrate and at least one channel in a bottom surface of the recess. The recess may be configured to accommodate a semiconductor device located over a surface of an interposer that is bonded to the package substrate. Accordingly, a minimum gap distance may be maintained between the semiconductor device and the package substrate, which may ensure that sufficient underfill material may flow between the semiconductor device and the package substrate and within the at least one channel, thereby improving of the structural coupling between the interposer and the package substrate, and reducing the likelihood of package defects, such as delamination, cracking, and/or popcorn defects.