MEMS Die Sealed by Processor Die in Substrate Cavity
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Solution Overview
Problem
Stress-sensitive device dies, such as MEMS dies, are vulnerable to damage from stresses induced during manufacturing, assembly, and use due to encapsulant material changes in moisture and temperature, which can cause deformation and impair performance.
Innovation Solution
An integrated device package design featuring a substrate with a cavity for the first stress-sensitive die, where a second die is positioned over the cavity to seal and shield the first die from external stresses, using an encapsulant over the second die to reduce assembly costs and protect the sensitive components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an encapsulant or molding material is applied over a die, then the die is protected and assembly costs are reduced, but the moisture content and material property changes of the encapsulant cause stresses that can damage the integrated device die or change stresses experienced by the die over its working life
Solution Approach 1:
The package is divided into distinct regions: a cavity region housing the stress-sensitive die and a separate encapsulant region. The encapsulant is applied only over portions of the substrate that do not contain the sensitive die, physically segmenting the stress source from the sensitive component while maintaining overall package integrity and reducing assembly complexity
Solution Approach 2:
The harmful encapsulant material is extracted or excluded from the cavity region containing the stress-sensitive die. By omitting the encapsulant over the die portion and using the cavity structure instead, the patent removes the source of moisture-induced stresses while preserving the protective and cost benefits of encapsulation in other areas
2Reliability
If traditional metal lid and cavity methods are used to protect stress-sensitive dies, then the die is well protected from stresses, but manufacturing and assembly costs increase
Solution Approach 1:
The patent replaces expensive metal lid and cavity structures with a more economical substrate-based cavity design. The substrate itself forms the cavity walls, eliminating the need for separate metal components. This substitution maintains stress protection functionality while significantly reducing material and assembly costs
Solution Approach 2:
The substrate serves multiple functions simultaneously: it provides mechanical support, forms the cavity structure through integrated recesses, and acts as the mounting platform for the die. This multi-functionality eliminates the need for separate metal lid and cavity components, reducing overall package complexity and cost while maintaining protective functionality
Data Source
AI summary
An integrated device package is disclosed. The package includes a substrate comprising a cavity through a top surface of the substrate. A first integrated device die is positioned in the cavity. The first integrated device die includes one or more active components. A second integrated device die is attached to the top surface of the substrate and positioned over the cavity. The second integrated device die covers the cavity. Encapsulant can cover the second integrate device die.