Fan-Out Package Structure Thin Interposer Integration
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Solution Overview
Problem
Conventional integration schemes for integrated circuits result in thick and large packages due to bonding components to an interposer and then to a package substrate, which is inefficient for compact and thin form factors required in modern applications.
Innovation Solution
A fan-out package structure is formed by placing device dies and die stacks on a release layer over a carrier, with metal pillars and dielectric layers, followed by molding and planarization, allowing for the formation of a thin interposer that integrates redistribution lines directly over the dies, eliminating the need for a separate interposer and reducing package thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If components are bonded to an interposer and then to a package substrate using conventional integration schemes, then electrical connectivity and structural support are achieved, but the package becomes thick and large in area
Solution Approach 1:
The patent merges the interposer formation process with die stacking and molding operations. The interposer is formed directly on the carrier substrate during the same process sequence as die placement and molding, eliminating the need for separate interposer fabrication and bonding steps. This integration reduces package thickness while maintaining electrical connectivity functions.
Solution Approach 2:
The interposer structure is prepared in advance on the carrier substrate before die stacking. Redistribution lines are formed on the carrier, and the interposer structure is preliminarily established with through-vias and conductive elements positioned ready for die attachment. This preliminary preparation enables thinner overall package structure by eliminating post-assembly thickening operations.
2Area of stationary object
If a separate interposer is used for integrating redistribution lines, then electrical connectivity is achieved, but the package area and thickness increase
Solution Approach 1:
The patent combines multiple manufacturing operations into a single integrated process flow. Die stacking, interposer formation, and molding are performed in sequence on the same carrier substrate without requiring separate manufacturing lines or additional bonding equipment. This merged approach reduces package area while maintaining manufacturing simplicity through process integration.
3Reliability
If conventional bonding methods are used to attach dies to interposer, then reliable electrical connectivity is achieved, but the package becomes larger and more complex
Solution Approach 1:
The patent extracts the interposer from its traditional role as a separate bonded component and integrates it directly into the carrier substrate structure. The interposer formation is extracted from post-die-attachment operations and performed beforehand on the carrier, allowing direct electrical connection through through-vias without requiring thick bonding layers or additional interface materials that would increase package thickness.
Data Source
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. One of the device die and the plurality of dies includes a semiconductor substrate and a through-via penetrating through the semiconductor substrate, A polymer region includes 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 and the second plurality of metal pillars. Redistribution lines are formed over the first and the second plurality of metal pillars.