3D IC Encapsulation With Copper Posts for Thin Die Protection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

There is a need for a package that effectively protects thin semiconductor dies while allowing for the formation of electrical connections to one or both surfaces of the die, as these dies are fragile and vulnerable to cracking or chipping.

Innovation Solution

The package includes a semiconductor die with a mold compound on its back surface and edges, copper posts extending through the mold compound to the top surface, and copper pillar bumps on the bottom surface, along with redistribution layers on both surfaces of the die to facilitate electrical connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a thin semiconductor die is used, then the device size is reduced and integration is improved, but the die becomes fragile and vulnerable to cracking or chipping

Engineering Contradiction:

Improvedie thicknessVSAvoiddie strength

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

A mold compound is applied over the back surface of the thin semiconductor die before packaging, creating a protective cushioning layer that prevents cracking and chipping during handling and operation. This protective layer is applied in advance to mitigate the fragility inherent in thin die designs.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The package combines the thin semiconductor die with a mold compound to create a composite structure. The mold compound provides mechanical strength and protection while allowing the die to maintain its thin profile for integration benefits.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If electrical connections are made to both surfaces of the die, then connectivity options are increased, but the package structure becomes more complex

Engineering Contradiction:

Improveconnection optionsVSAvoidpackage structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The electrical connection system is segmented into two independent surfaces: the front surface with copper pillar bumps and the back surface with copper posts extending through the mold compound. This segmentation allows each surface to be optimized independently for its specific connection requirements, increasing versatility while managing complexity through modular design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Electrical connections are established in two dimensions - both the front and back surfaces of the die are utilized for connections. This dimensional approach to connectivity provides more routing options and design flexibility without requiring additional vertical stacking complexity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12347763B2Packaging of three-dimensional integrated circuit by encapsulation with copper posts and double sided redistribution layer

Publication Date: 2025.07.01 ROCKLEY PHOTONICS LTD

AI summary

A semiconductor package. In some embodiments, the package has a top surface and a bottom surface, and includes: a semiconductor die having a front surface, a back surface, and a plurality of edges; a mold compound, on the back surface of the die and the edges of the die; a plurality of first conductive elements extending through the mold compound on the back surface of the die to the top surface of the package; and a plurality of second conductive elements on the bottom surface of the package.