Wafer Level Package Terminal Fixation via Segmented Encapsulant
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Solution Overview
Problem
Current wafer level packaging techniques face challenges in reducing manufacturing costs without compromising package function, particularly in the formation of external connection terminals which are prone to detachment due to water vapor pressure.
Innovation Solution
A wafer level package design featuring a rerouting pattern on a semiconductor substrate with a first encapsulant pattern having a via hole to expose the rerouting pattern, and an external connection terminal separated by a gap from the via hole's sidewall, along with a second encapsulant pattern filling the gap to enhance terminal fixation and prevent detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If external connection terminal is formed directly on rerouting pattern without gap, then manufacturing process is simplified, but terminal detachment occurs due to water vapor pressure
Solution Approach 1:
The encapsulant structure is segmented into multiple regions: a first encapsulant region directly contacting the external connection terminal, and a second encapsulant region forming a gap with the terminal. This segmentation allows the first region to provide strong fixation while the second region manages water vapor pressure, resolving the contradiction between manufacturing simplicity and terminal stability.
Solution Approach 2:
The second encapsulant pattern acts as an intermediary element between the external connection terminal and the surrounding environment. It creates a controlled gap that prevents water vapor pressure from directly acting on the terminal, thereby maintaining terminal fixation stability without complicating the manufacturing process.
2Reliability
If gap distance between via hole sidewall and external connection terminal is increased, then terminal detachment is prevented, but package volume increases
Solution Approach 1:
The encapsulant structure exhibits local quality variations: the first encapsulant region has properties optimized for terminal fixation with direct contact, while the second encapsulant region has properties optimized for water vapor management with a controlled gap. This local differentiation prevents terminal detachment while minimizing overall package volume increase.
Solution Approach 2:
The gap between the via hole sidewall and external connection terminal is utilized as a three-dimensional space filled with the second encapsulant pattern. This dimensional approach allows the gap to serve as both a protective feature and a volume-efficient design element, preventing terminal detachment without proportionally increasing package volume.
3Ease of manufacture
If first encapsulant pattern fully covers rerouting pattern without via hole, then manufacturing is simpler, but external connection terminal cannot be formed
Solution Approach 1:
The encapsulant pattern is segmented into a first encapsulant pattern that covers the rerouting pattern and forms the external connection terminal, and a second encapsulant pattern that fills the gap. This segmentation enables both full encapsulation for manufacturing simplicity and via hole formation for external connection capability.
Solution Approach 2:
The via hole structure is nested within the first encapsulant pattern, which itself is nested within the overall package structure. The second encapsulant pattern is then nested in the gap region. This nested arrangement allows the encapsulant to both cover the rerouting pattern and expose the external connection terminal through the via hole.
Data Source
AI summary
In one embodiment, a wafer level package includes a rerouting pattern formed on a semiconductor substrate and a first encapsulant pattern overlying the rerouting pattern. The first encapsulant pattern has a via hole to expose a portion of the rerouting pattern. The package additionally includes an external connection terminal formed on the exposed portion of the rerouting pattern. An upper section of the sidewall and a sidewall of the external connection terminal may be separated by a gap distance. The gap distance may increase toward an upper surface of the encapsulant pattern.