Split MEMS Gyroscope Stacked Die Architecture
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Solution Overview
Problem
There is a demand for microelectronic packages with reduced footprints that contain MEMS gyroscopes and additional sensors, with the need for fluidly-isolated cavities to optimize sensor performance, and existing technologies struggle to achieve this while maintaining efficient manufacturing processes.
Innovation Solution
The solution involves splitting MEMS gyroscope structures between at least two stacked MEMS die, with hermetic cavities containing different pressures to optimize performance, and using a high-volume, low-cost manufacturing process that includes forming Through Substrate Vias and bonding materials to create a 'split-gyroscope' architecture, allowing for reduced planform dimensions and efficient packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If MEMS gyroscope and additional sensors are integrated on a single die or stacked dies, then device functionality is achieved, but planform footprint remains too large for advanced mobile applications
Solution Approach 1:
The gyroscope structure is divided into two separate MEMS dies (first MEMS die with first gyroscope structure, second MEMS die with second gyroscope structure) that are stacked and bonded together. This segmentation allows each die to be optimized independently and enables the integration of additional sensors on one of the dies without increasing the planform footprint, as the stacked configuration utilizes the third dimension for integration.
Solution Approach 2:
The patent transitions from a planar integration approach to a three-dimensional stacked architecture. By bonding MEMS dies in a stacked relationship, the design utilizes the vertical dimension (thickness direction) to accommodate multiple gyroscope structures and additional sensors, thereby reducing the planform footprint while maintaining or enhancing device functionality.
2Reliability
If different MEMS devices are enclosed in fluidly-isolated cavities with different pressures, then sensor performance is optimized, but manufacturing complexity increases
Solution Approach 1:
The patent implements separate hermetic cavities for the first and second MEMS gyroscope structures, with the option to enclose additional sensors in separate cavities. Each cavity can be independently filled with different gases or vacuum conditions optimized for the specific sensor performance requirements. The segmentation of cavities allows independent pressure control without requiring complex inter-cavity isolation mechanisms.
3Area of stationary object
If stacked die configuration is used to reduce footprint, then planform dimensions are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs preliminary alignment features and bonding techniques that ensure precise registration between stacked MEMS dies before final bonding. By preparing alignment structures in advance and using controlled bonding processes, the design achieves high stacking precision without requiring extremely tight tolerances on individual component dimensions, thereby reducing overall manufacturing difficulty.
Data Source
AI summary
Methods for fabricating microelectronic packages and microelectronic packages having split gyroscope structures are provided. In one embodiment, the microelectronic package includes a first Microelectromechanical Systems (MEMS) die having a first MEMS gyroscope structure thereon. The microelectronic package further includes a second MEMS die, which has a second MEMS gyroscope structure thereon and which is positioned in a stacked relationship with the first MEMS die. The first and second MEMS gyroscope structures overlap as taken along a first axis orthogonal to a principal axis of the first MEMS die.