Semiconductor Package Inner Outer Cavities Hermetic Seal
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Solution Overview
Problem
Existing semiconductor package structures have a low hermetic seal effectiveness, which affects the lifespan and performance of semiconductor devices by allowing moisture, particles, and contamination to reach sensitive components like communication ICs, MEMS dies, and optical dies, leading to issues such as impedance changes and signal deterioration.
Innovation Solution
A semiconductor package structure is designed with a substrate, one or more lids, and caps that define hermetic cavities with pressures different from atmospheric pressure, using adhesive or bonding materials to create a sealed environment, and optionally incorporating moisture getters and inert gases to enhance the seal and prevent contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor package structures are used, then manufacturing is simpler, but hermetic seal effectiveness is low allowing moisture and contamination to reach sensitive components
Solution Approach 1:
The package structure is divided into multiple sealed cavities, each containing specific sensitive components. The cavity is segmented by a first lid and a second lid with different opening orientations, creating distinct hermetic zones that independently protect different components from moisture and contamination.
Solution Approach 2:
One cavity structure is nested within another larger cavity structure. The first cavity containing sensitive components is nested within a second cavity that provides additional hermetic protection, creating a multi-layered defense against environmental degradation.
2Reliability
If hermetic seal effectiveness is improved through better sealing, then reliability increases, but manufacturing precision requirements increase
Solution Approach 1:
Different sealing structures are applied to different regions of the package. The first lid and second lid have different opening orientations and sealing configurations tailored to their specific functional requirements, allowing optimized sealing for each region rather than a uniform approach.
Solution Approach 2:
A pressure equalization hole is introduced as an intermediary element between the first cavity and second cavity. This hole allows pressure equalization during manufacturing processes, facilitating easier sealing without requiring extremely high precision, while still maintaining hermetic effectiveness during operation.
3Object-affected harmful factors
If pressure inside cavity is increased above atmospheric pressure, then moisture ingress is prevented, but stress on seals increases
Solution Approach 1:
The cavity is pre-filled with inert gas at a pressure higher than atmospheric pressure before final sealing. This preliminary pressurization creates a pressure differential that prevents moisture ingress during operation, while the pressure equalization hole allows stress relief during manufacturing.
Solution Approach 2:
The cavity is filled with inert gas (such as nitrogen or dry air) at elevated pressure. This inert atmosphere not only prevents moisture ingress through the pressure differential but also provides a chemically inert environment that protects sensitive components from oxidation and contamination.
Data Source
AI summary
A semiconductor package structure includes a substrate, a semiconductor die, a lid and a cap. The semiconductor die is disposed on the substrate. The lid is disposed on the substrate. The cap is disposed on the lid. The substrate, the lid and the cap define a cavity in which the semiconductor die is disposed, and a pressure in the cavity is greater than an atmospheric pressure outside the cavity.