Packaging Substrate Opening for Uniform Interposer Underfill

Solution Overview

Problem

The application of underfill material between an interposer and a packaging substrate becomes difficult due to the increased lateral dimensions of interposers, leading to non-uniform distribution as the underfill material needs to be pushed through a long extrusion distance.

Innovation Solution

A packaging substrate with an underfill injection opening is used to apply underfill material through an opening in the packaging substrate, allowing uniform distribution by injecting it from the center region of an array of solder material portions, accommodating surface mount dies if present, and ensuring adequate space for underfill material application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the lateral dimensions of interposers are increased to accommodate larger components, then the packaging capacity is improved, but the underfill material distribution becomes non-uniform due to the increased extrusion distance

Engineering Contradiction:

Improveinterposer lateral dimensionsVSAvoidunderfill material distribution uniformity

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The packaging substrate is segmented by creating a through-opening that divides the underfill application path into two segments: from the periphery to the opening, and from the opening to the center region. This segmentation reduces the effective extrusion distance for each segment, enabling uniform underfill distribution even across large interposer dimensions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The through-opening acts as an intermediary structure that facilitates underfill material delivery. By providing a direct pathway through the packaging substrate, it mediates the transport of underfill material from the application point to the center region, ensuring uniform distribution without being constrained by the full lateral dimension of the interposer.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If the underfill material is applied from the periphery to fill the entire gap, then the coverage area is improved, but the extrusion distance increases causing non-uniform distribution

Engineering Contradiction:

Improveunderfill coverage areaVSAvoidunderfill extrusion distance

Core Design Contradiction:

Area of stationary objectVSLength of moving object

Solution Approach 1:

The underfill application approach transitions from a two-dimensional periphery-based application to a three-dimensional approach utilizing the through-opening. The underfill material is applied through the opening in the vertical dimension, allowing it to reach the center region directly and reducing the lateral extrusion distance required for complete coverage.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If the packaging substrate is made larger to accommodate more components, then the component integration capacity is improved, but the underfill material application difficulty increases

Engineering Contradiction:

Improvecomponent integration capacityVSAvoidunderfill material application ease

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The packaging substrate is segmented by creating a through-opening that divides the underfill application path into two segments: from the periphery to the opening, and from the opening to the center region. This segmentation reduces the effective extrusion distance for each segment, enabling uniform underfill distribution even across large interposer dimensions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The through-opening acts as an intermediary structure that facilitates underfill material delivery. By providing a direct pathway through the packaging substrate, it mediates the transport of underfill material from the application point to the center region, ensuring uniform distribution without being constrained by the full lateral dimension of the interposer.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12588525B2Packaging substrate including an underfill injection opening and methods of forming the same

Publication Date: 2026.03.24 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

An assembly including at least one semiconductor die and an interposer is provided. A packaging substrate including substrate bonding pads is provided. The packaging substrate includes a first horizontal surface facing the assembly, a second horizontal surface located on an opposite side of the first horizontal surface, and an opening extending between the first horizontal surface and the second horizontal surface. The assembly is attached to the packaging substrate by bonding first solder material portions bonded to a respective one of the substrate bonding pads and to a respective one of first interposer bonding pads located on the interposer.