MEMS Package Cavity Carrier and Metal Shielding
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Solution Overview
Problem
Conventional microelectromechanical system packages are difficult to mass produce due to their large profile and limited application, requiring additional covers for protection which increases thickness and complexity.
Innovation Solution
A method using a silicon wafer as a carrier to form cavities, depositing a metal layer and isolation layer, and connecting microelectromechanical system chips to the conductive trace layer, eliminating the need for additional covers and reducing thickness by shielding the chips from electromagnetic interference with the metal layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional covers are used to protect the MEMS device from electromagnetic interference and environmental influences, then the protection capability is improved, but the package thickness increases and mass production becomes difficult
Solution Approach 1:
The patent combines multiple protective functions (EM shielding, environmental protection, structural support) into a single integrated substrate structure. The substrate serves simultaneously as the mounting platform for the MEMS device, the EM shield through its conductive nature, and the environmental barrier through its sealed cavity design, eliminating the need for separate cover components.
Solution Approach 2:
The substrate is designed to perform multiple functions: mechanical support for the MEMS device, electromagnetic shielding through its conductive material, environmental protection via the sealed cavity, and electrical connection through integrated traces. This multi-functional design reduces the overall package thickness while maintaining comprehensive protection.
2Object-affected harmful factors
If additional covers and conductive layers are used to shield the MEMS device, then the electromagnetic shielding capability is improved, but the device complexity increases
Solution Approach 1:
The patent merges the EM shielding function with the substrate structure itself. The conductive substrate forms an integrated shield that combines structural support and electromagnetic protection in a single component, reducing the number of separate layers and simplifying the overall package design.
Solution Approach 2:
The substrate serves itself by providing both mechanical support and electromagnetic shielding through its inherent conductive properties. The same substrate that mounts the MEMS device also provides the EM shield, eliminating the need for additional dedicated shielding layers and reducing overall complexity.
3Reliability
If conventional package structures with covers are used, then the protection from environmental influences is improved, but the mass production capability deteriorates
Solution Approach 1:
The patent segments the protective function into the substrate's integrated cavity structure rather than using a separate cover component. This segmentation allows for direct assembly and simplifies the manufacturing process, enabling better mass production capability while maintaining environmental protection through the sealed cavity design.
Solution Approach 2:
The substrate is pre-designed with integrated shielding and sealing features before the MEMS device is mounted. The cavity structure and conductive properties are built into the substrate during substrate fabrication, allowing subsequent assembly steps to be simpler and more suitable for mass production.
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
The method reduces package thickness and enhances protection from external interference, facilitating easier mass production and broader application of microelectromechanical system packages.
Implementation Method 1
the metal layer formed on the inside surface of the cavity is able to shield the microelectromechanical system chip from external electromagnetic interference
Data Source
AI summary
A method for manufacturing a microelectromechanical system package is provided. A plurality of cavities is first formed on a surface of a silicon wafer. The surface of the silicon wafer is then bonded to the microelectromechanical system wafer in such a manner that the active areas of the chips on the microelectromechanical system wafer are corresponding to the cavities on the silicon wafer. The structure assembly of the two wafers is finally singulated to form individual microelectromechanical system chips whose active areas are covered by the cavities. In this way, the profile of the microelectromechanical system package may be reduced accordingly.