Package-on-Package Structure With Direct RDL on Encapsulant
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving compact and reliable package-on-package (POP) structures due to the complexity and thickness of conventional packaging methods, which often result in increased production costs and reliability issues related to voids and breakage of conductive traces.
Innovation Solution
The method involves forming a first redistribution structure on a carrier with a de-bonding layer, followed by the placement of a die and conductive structures, encapsulation, and the creation of a second redistribution structure directly on the encapsulant without intermediate dielectric layers, allowing for flip-chip bonding and reduced thickness, thereby eliminating unnecessary layers and enhancing planarity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packaging methods with multiple dielectric layers and adhesive films are used, then structural completeness and electrical connectivity are ensured, but the overall thickness increases and reliability decreases due to voids and trace breakage
Solution Approach 1:
The patent removes unnecessary dielectric layers and adhesive films from the conventional packaging structure. Specifically, the method eliminates at least one dielectric layer between the first and second redistribution structures, and removes adhesive films that typically bond these layers, thereby reducing thickness and eliminating sources of voids and reliability issues
Solution Approach 2:
The patent merges the function of multiple layers into fewer integrated structures. The encapsulant directly encapsulates the die and conductive structures, and the second redistribution structure is formed directly on the encapsulant without intermediate dielectric layers, creating a more integrated and compact package structure
2Ease of manufacture
If multiple dielectric layers and adhesive films are included in the package structure, then electrical connectivity and structural support are maintained, but manufacturing complexity and production costs increase
Solution Approach 1:
The patent extracts and removes unnecessary manufacturing steps associated with forming and bonding multiple dielectric layers and adhesive films. By eliminating at least one dielectric layer and the adhesive films, the manufacturing process is simplified while maintaining essential structural and electrical functions
Solution Approach 2:
Instead of building up the package structure with multiple intermediate layers as in conventional methods, the patent inverts the approach by forming the second redistribution structure directly on the encapsulant, reversing the traditional layering sequence and simplifying the manufacturing workflow
Data Source
AI summary
A manufacturing method of a package-on-package structure includes forming a first package structure and staking a second package structure over the first package structure. The first package structure is formed by at least the following steps. A first redistribution structure is provided. Conductive structures are formed on the first redistribution structure. A die is placed between the conductive structures. The die and the conductive structures are encapsulated by an encapsulant. The encapsulant is planarized such that an entirety of a top surface of the encapsulant is coplanar with an entirety of top surfaces of the conductive structures. A second redistribution structure is formed on the encapsulant. The second redistribution structure includes a conductive pattern layer that is in physical contact with the top surfaces of the encapsulant and the conductive structures. An entire bottom surface of the conductive pattern layer is located at a same level height.