Fan-Out Package Structure Reducing Thickness via Lateral Redistribution

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Solution Overview

Problem

Conventional integrated circuit packaging methods result in thick and large packages due to the bonding of different components to an interposer, which is then bonded to a package substrate, leading to inefficiencies in size and thickness.

Innovation Solution

A fan-out package structure is formed by placing device dies and die stacks over a carrier with adhesive, molding material is used to fill gaps, and redistribution lines are formed to create a thin interposer that supports the package without the need for a separate interposer, allowing for a significantly reduced package thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional bonding schemes are used to integrate different components, then functional integration is achieved, but package thickness and area increase significantly

Engineering Contradiction:

Improvefunctional integrationVSAvoidpackage thickness

Core Design Contradiction:

Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The patent transitions from vertical stacking (conventional bonding) to lateral expansion (fan-out configuration). The interposer extends horizontally beyond the die footprint, allowing I/O pads to be redistributed laterally rather than vertically, thus reducing package thickness while maintaining integration capability

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The package structure is divided into distinct functional regions: the die, the interposer with redistribution layers, and the molding compound. This segmentation allows each component to be optimized independently, with the interposer serving as a thin intermediary that redistributes signals without adding significant thickness

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If conventional bonding schemes are used to integrate different components, then functional integration is achieved, but package area increases significantly

Engineering Contradiction:

Improvefunctional integrationVSAvoidpackage area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The die is nested within the interposer structure, which itself is embedded in the molding compound. The interposer's I/O pads are positioned within the molding compound footprint rather than extending the overall package area, achieving compact integration of multiple functional elements

Inventive Principle:

Principle #7Nested doll (Nesting)

3Reliability

If a separate interposer and package substrate are used, then component support is achieved, but manufacturing complexity increases

Engineering Contradiction:

Improvecomponent supportVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The interposer and package substrate functions are merged into a single integrated structure. The interposer serves both as a mechanical support platform and as the substrate for mounting the die, eliminating the need for separate bonding steps and reducing manufacturing complexity

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8803306B1Fan-out package structure and methods for forming the same

Publication Date: 2014.08.12 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A package includes a device die including a first plurality of metal pillars at a top surface of the device die. The package further includes a die stack including a plurality of dies bonded together, and a second plurality of metal pillars at a top surface of the die stack. A polymer region includes first portions encircling the device die and the die stack, wherein a bottom surface of the polymer region is substantially level with a bottom surface of the device die and a bottom surface of the die stack. A top surface of the polymer region is level with top ends of the first plurality of metal pillars and top ends of the second plurality of metal pillars. Redistribution lines are formed over and electrically coupled to the first and the second plurality of metal pillars.