Stacked MEMS Package with Composite Substrates for Compact Shielding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing MEMS sensor packages, such as capacitive microphones, face challenges with large dimensions, limited design freedom, and inefficiencies in space utilization due to the need for specific molding tools and incompatible pitch and layout, which affect the bulkiness and acoustic performance of the device.
Innovation Solution
A packaged MEMS device is manufactured using stacked composite substrates with separate chambers and support structures, allowing for optimized dimensions and reduced bulk through the use of laminated BT boards, metal coatings, and electroplating techniques, enabling precise tuning of front and back chambers for improved acoustic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a molded cap package is used to enclose MEMS die and ASIC side-by-side, then the package provides electromagnetic shielding and structural support, but the package dimensions become large and design freedom is limited due to compatibility requirements with molding tools
Solution Approach 1:
The patent transitions from a planar side-by-side arrangement to a three-dimensional stacked configuration, placing the MEMS die and ASIC vertically one above the other on the substrate. This vertical stacking enables compact packaging while maintaining electromagnetic shielding through the cap structure, effectively resolving the contradiction between package size and shielding performance.
Solution Approach 2:
The patent implements a nested structure where the MEMS die and ASIC are positioned in close proximity on the substrate, with the cap enclosing both components. The chambers are nested within the package structure, with the first chamber accommodating the MEMS die and the second chamber accommodating the ASIC, allowing efficient space utilization and reduced package dimensions.
2Manufacturing precision
If specific molding tools are used for each variation of dimensions and shapes, then the cap can be precisely formed, but the device complexity and manufacturing cost increase due to dedicated tools for each configuration
Solution Approach 1:
The patent employs a universal molding tool that can accommodate multiple die sizes and configurations through adjustable positioning mechanisms and standardized tooling interfaces. This single multi-functional tool replaces the need for dedicated molding tools for each specific package variation, reducing device complexity and manufacturing cost while maintaining precision.
Solution Approach 2:
The patent utilizes adjustable molding parameters such as pressure, temperature, and tool positioning to accommodate different cap dimensions and shapes. By changing these process parameters rather than requiring different physical tools, the system achieves manufacturing precision across multiple configurations without increasing device complexity.
3Ease of manufacture
If the pitch and layout of molding and punching tools are fixed, then the manufacturing process is simplified, but the compatibility with varying array contact dimensions and configurations is reduced
Solution Approach 1:
The patent incorporates dynamic positioning systems in the molding and punching tools that allow real-time adjustment of pitch and layout parameters. This enables the fixed manufacturing process to adapt to varying contact array dimensions and configurations, maintaining ease of manufacture while achieving versatility across different designs.
Solution Approach 2:
The patent divides the contact array into modular segments that can be independently positioned and configured. The molding and punching tools are designed to work with these segmented contacts, allowing the fixed tool pitch and layout to accommodate variable contact configurations through modular arrangement, thus maintaining manufacturing simplicity while achieving adaptability.
4Reliability
If two dice are accommodated side-by-side with a cap, then the package provides electromagnetic shielding, but the design freedom in sizing the front and back chambers is insufficient
Solution Approach 1:
The patent transitions from a planar side-by-side arrangement to a three-dimensional stacked configuration, enabling independent sizing of front and back chambers in the vertical dimension. This allows the first chamber (accommodating MEMS die) and second chamber (accommodating ASIC) to be optimized independently for their respective functions while maintaining electromagnetic shielding through the enclosing cap.
Solution Approach 2:
The patent segments the package into distinct functional chambers: a first chamber for the MEMS die with optimized front and back volumes, and a second chamber for the ASIC. This segmentation allows independent dimensioning of each chamber to meet specific acoustic and electrical performance requirements while the overall package structure provides electromagnetic shielding.
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 results in a more compact, robust, and modular package design that optimizes the front and back chambers, reduces parasitic capacitance, and enhances the overall acoustic performance by allowing for precise control over chamber dimensions and separation, while also providing effective shielding from electromagnetic interference.
Implementation Method 1
electroplating techniques
Implementation Method 2
metal coatings
Implementation Method 3
The cap 2 may be made of metal... so as to prevent noise due to external electromagnetic signals (by providing a sort of Faraday cage)
Data Source
AI summary
A packaged MEMS device, wherein at least two support structures are stacked on each other and are formed both by a support layer and a wall layer coupled to each other and delimiting a respective chamber. The chamber of the first support structure is upwardly delimited by the support layer of the second support structure. A first and a second dice are accommodated in a respective chamber, carried by the respective support layer of the first support structure. The support layer of the second support structure has a through hole allowing wire connections to directly couple the first and the second dice. A lid substrate, coupled to the second support structure, closes the chamber of the second support structure.