Fan-out Package Blocking Layer Prevents Encapsulant Bleeding
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Solution Overview
Problem
Fan-out semiconductor packages face issues with encapsulant bleeding into redistribution layers, leading to reliability problems such as open defects, connectivity decreases, and electrical short-circuits, due to the lack of a blocking layer that prevents encapsulant from seeping into the redistribution layer during the encapsulation process.
Innovation Solution
Incorporating a blocking layer around the through-hole of the first interconnection member, which is positioned differently from the redistribution layer, to prevent encapsulant from bleeding into the redistribution layer, thereby maintaining the integrity of the redistribution layer and ensuring reliable connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fan-out semiconductor package is constructed with an interconnection member having a redistribution layer, then the package achieves a compact size with multiple pins, but the encapsulant bleeds into the redistribution layer causing reliability issues
Solution Approach 1:
A blocking layer is introduced as an intermediary component between the encapsulant and the redistribution layer. This blocking layer acts as a barrier that prevents the encapsulant from bleeding into the redistribution layer, thereby eliminating the harmful effect while maintaining the compact fan-out package structure.
Solution Approach 2:
The interconnection member is segmented into multiple functional layers: the redistribution layer for electrical connections and the blocking layer for preventing encapsulant intrusion. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between achieving compact integration and preventing harmful encapsulant bleeding.
2Ease of manufacture
If the encapsulation process is performed without a blocking layer, then the manufacturing process is simpler, but the encapsulant seeps into the redistribution layer causing open defects and connectivity issues
Solution Approach 1:
The blocking layer serves as a mediator that maintains uniform encapsulant thickness by preventing encapsulant intrusion into the redistribution layer. This ensures manufacturing precision in terms of encapsulant thickness uniformity while adding only one more layer to the structure, keeping the manufacturing process relatively simple.
3Volume of moving object
If the blocking layer is positioned at the same location as the redistribution layer, then the structure is more compact, but the encapsulant cannot be effectively blocked from the through-hole
Solution Approach 1:
The blocking layer is positioned in a different spatial location (at the through-hole opening) rather than overlapping with the redistribution layer. This dimensional separation allows the blocking layer to effectively prevent encapsulant intrusion from the through-hole while maintaining overall package compactness through optimized spatial arrangement.
Data Source
AI summary
A fan-out semiconductor package includes: a first interconnection member having a through-hole; a semiconductor chip disposed in the through-hole and having an active surface having connection pads disposed thereon and an inactive surface; a second interconnection member disposed on the first interconnection member and the active surface of the semiconductor chip and including a redistribution layer electrically connected to the connection pads; and an encapsulant encapsulating at least portions of the first interconnection member and the semiconductor chip. The first interconnection member includes a first insulating layer in contact with the second interconnection member, a first redistribution layer disposed on a surface of the first insulating layer in contact with the second interconnection member and electrically connected to the connection pads, and a blocking layer disposed on the surface of the first insulating layer on which the first redistribution layer is disposed and surrounding the through-hole.