Multi-chip Fan-Out Package Pre-Formed Redistribution
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Solution Overview
Problem
Current semiconductor packaging technologies face challenges in achieving high integration density and reliable redistribution structures due to thermal limitations of molding materials, which restrict the use of advanced processes like damascene and dual-damascene for forming front side redistribution structures.
Innovation Solution
The method involves pre-forming redistribution structures over a carrier that is more tolerant to high temperatures, allowing the use of damascene and dual-damascene processes to achieve finer pitches and smaller vias, and attaching these pre-formed structures to the semiconductor package after functional testing of dies to ensure only known good dies are integrated, thereby enhancing yield and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If molding material is used for semiconductor packaging, then the package provides structural support and protection, but the thermal limitations of the molding material restrict the use of advanced processes like damascene and dual-damascene for forming redistribution structures
Solution Approach 1:
The patent divides the packaging structure into two segments: a carrier substrate that provides thermal stability for advanced manufacturing processes, and a molding material that provides structural protection. This segmentation allows each material to be optimized for its specific function without compromise.
Solution Approach 2:
The carrier substrate acts as an intermediary between the manufacturing process and the molding material. It provides the thermal stability needed for damascene processes while the molding material provides structural support, mediating between the conflicting requirements of advanced manufacturing and thermal limitations.
2Manufacturing precision
If redistribution structures are formed after die attachment, then the process is simpler, but the line pitches are coarser and integration density is lower
Solution Approach 1:
The redistribution structures are pre-formed on the carrier substrate before die attachment using advanced damascene processes. This preliminary action enables finer line pitches and higher manufacturing precision while the modular approach keeps the overall process manageable.
3Productivity
If all dies are packaged without functional testing, then production throughput is higher, but yield is lower due to inclusion of defective dies
Solution Approach 1:
Functional testing of dies is performed before attachment to the carrier substrate with pre-formed redistribution structures. This preliminary action ensures that only known good dies are packaged, improving yield while the efficient testing and modular approach minimize impact on throughput.
4Quantity of substance
If multiple semiconductor dies are packaged in one package, then integration density increases, but the complexity of redistributing signals between multiple dies increases
Solution Approach 1:
The carrier substrate with its pre-formed redistribution structures acts as an intermediary that simplifies signal routing between multiple dies. The complex redistribution logic is embedded in the pre-formed structures on the carrier, reducing the complexity of inter-die signal management.
Data Source
AI summary
A method includes surrounding a die and a conductive pillar proximate the die with a molding material, where the die and the conductive pillar are disposed over a first side of a first redistribution structure, where a second side of the first redistribution structure opposing the first side is attached to a first carrier; bonding conductive pads disposed on a first surface of a pre-made second redistribution structure to the die and to the conductive pillar, where a second surface of the pre-made second redistribution structure opposing the first surface is attached to a second carrier; after bonding the conductive pads, removing the second carrier to expose conductive features of the pre-made second redistribution structure proximate the second surface; and forming conductive bumps over and electrically coupled to the conductive features of the pre-made second redistribution structure.