Package Substrate Oblique Landing Pads Void Reduction

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Solution Overview

Problem

In the flip chip process for semiconductor package manufacturing, the difference in thermal expansion coefficients between the semiconductor chip and the package substrate can lead to voids due to uneven flow rates of the mold resin, which compromises the integrity of the package.

Innovation Solution

A package substrate with through-holes and obliquely extending landing pads on the package substrate core, where conductive bumps are formed directly on the landing pads, and a molding material that fills the through-holes and encapsulates the bumps, ensuring uniform underfill flow and minimizing voids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mold resin is used to fill spaces between the semiconductor chip and the package substrate, then the difference in thermal expansion coefficient is relieved and solder bumps are protected, but voids can be generated due to difference in flow rate of the mold resin

Engineering Contradiction:

Improvepackage integrityVSAvoidvoid formation

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The package substrate is divided into a chip mounting region and a peripheral region, with through-holes strategically positioned to segment the mold resin flow path. This segmentation allows the mold resin to flow more uniformly through distinct regions, preventing void formation while maintaining package integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Through-holes are introduced as intermediary structures that facilitate uniform mold resin flow between the chip mounting region and peripheral region. These holes act as flow channels that mediate the resin distribution, ensuring even filling and eliminating voids caused by flow rate differences.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If landing pads are disposed on the package substrate, then electrical connection is established, but the structure complexity increases

Engineering Contradiction:

Improveelectrical connectionVSAvoidlanding pad structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The landing pads serve multiple functions: they provide electrical connection between the semiconductor chip and the package substrate, and they act as structural support elements during the molding process. This multi-functionality reduces the need for separate components, simplifying the overall device structure while maintaining reliable electrical connection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The landing pad structure is merged with the package substrate, integrating the electrical connection function directly into the substrate rather than using separate connection elements. This merging reduces component count and simplifies the overall device complexity while ensuring reliable electrical connection.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10607905B2Package substrate for a semiconductor package having landing pads extending toward a through-hole in a chip mounting region

Publication Date: 2020.03.31 SAMSUNG ELECTRONICS CO LTD

AI summary

A semiconductor package includes a package substrate including at least one through-hole in a chip mounting region, a plurality of wiring patterns at a top surface of the package substrate. The wiring patterns include respective extension portions and respective landing pads. At least some of the landing pads obliquely extend toward the through-hole. Conductive bumps are formed on corresponding landing pads to connect to a semiconductor chip mounted on the chip mounting region of the package substrate. A molding material extends between the top surface of the package substrate and the semiconductor chip and fills the through-hole.