Photosensitive Encapsulant for Conductive Post Handling
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Solution Overview
Problem
The challenge in semiconductor manufacturing lies in forming z-direction electrical interconnects for stacked wafer level chip scale semiconductor packages, as traditional methods like metal plating are time-consuming and costly, and mechanical conductive bonding faces difficulties due to high aspect ratios, leading to handling issues and reduced manufacturing yield.
Innovation Solution
The method involves providing a substrate with conductive posts, disposing a photosensitive material around them, forming openings to expose the substrate, and placing a semiconductor die within these openings, followed by depositing an encapsulant to structurally support and protect the z-direction conductive posts during fabrication, using a photosensitive encapsulant to facilitate easier handling and integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal plating is used to form z-direction electrical interconnects, then electrical connectivity is achieved, but manufacturing time and cost increase
Solution Approach 1:
The patent extracts the conductive posts from the substrate before final assembly, allowing them to be pre-formed and pre-positioned. This eliminates the time-consuming metal plating step during final package assembly, as the conductive posts are already in place to receive the semiconductor die
Solution Approach 2:
The conductive posts are prepared in advance on the substrate, and the substrate with pre-positioned conductive posts is used as a carrier throughout the manufacturing process. This preliminary preparation of conductive interconnect structures enables faster final assembly without compromising electrical connectivity
2Reliability
If mechanical conductive bonding is used to form z-direction electrical interconnects, then electrical connectivity is achieved, but handling difficulty increases due to high aspect ratio
Solution Approach 1:
The substrate acts as an intermediary carrier that supports the conductive posts during manufacturing and assembly. This intermediary structure provides mechanical stability and ease of handling, allowing the high aspect ratio conductive posts to be manipulated indirectly through the substrate rather than directly, thus improving ease of operation
Solution Approach 2:
The photosensitive encapsulant material is applied as a thin film that conforms to the substrate and conductive posts, providing structural support and protection during handling. This flexible encapsulant layer enables easier manipulation of the assembly without damaging the delicate high aspect ratio conductive posts
3Strength
If conductive posts are embedded in structurally protective encapsulant, then structural support and protection are provided, but manufacturing complexity increases
Solution Approach 1:
The patent merges the structural support function and the protective encapsulation function into a single integrated process step. The photosensitive encapsulant is applied to embed the conductive posts and provide both structural support and protection simultaneously, rather than requiring separate steps for each function, thus reducing manufacturing complexity
Solution Approach 2:
The photosensitive encapsulant material serves multiple functions: it provides structural support to the conductive posts, protects them during handling and assembly, and enables precise positioning through photolithographic patterning. This multi-functional material reduces the number of separate manufacturing steps and components needed
4Ease of operation
If photosensitive encapsulant is used to facilitate handling and integration, then ease of operation improves, but material complexity increases
Solution Approach 1:
The photosensitive encapsulant's key property is its ability to change from a liquid or soft state to a rigid solid state through UV irradiation. This parameter change enables the material to provide structural support after application, improving handling ease during subsequent steps without requiring complex additional materials or processes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach simplifies the formation of z-direction electrical interconnects, reduces manufacturing complexity and costs, and enhances the yield of semiconductor devices by providing structural support and protection during the fabrication process, allowing for more efficient stacking and integration of semiconductor packages.
Implementation Method 1
disposing a photosensitive material over the substrate and around the conductive posts
Data Source
AI summary
A semiconductor package includes a post carrier having a base plate and plurality of conductive posts. A photosensitive encapsulant is deposited over the base plate of the post carrier and around the conductive posts. The photosensitive encapsulant is etched to expose a portion of the base plate of the post carrier. A semiconductor die is mounted to the base plate of the post carrier within the etched portions of the photosensitive encapsulant. A second encapsulant is deposited over the semiconductor die. A first circuit build-up layer is formed over the second encapsulant. The first circuit build-up layer is electrically connected to the conductive posts. The base plate of the post carrier is removed and a second circuit build-up layer is formed over the semiconductor die and the photosensitive encapsulant opposite the first circuit build-up layer. The second circuit build-up layer is electrically connected to the conductive posts.