3D Stacked MEMS Package Structure With Shielding
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Solution Overview
Problem
Current MEMS device package structures face challenges with signal interference between closely packed MEMS elements, leading to reduced yield and reliability, and require additional controlling units, resulting in a larger package area that hinders miniaturization.
Innovation Solution
The package structure incorporates a substrate with recesses, where a first MEMS chip with a through-substrate via is formed, followed by an intermediate chip with signal conversion and control units, and a second MEMS chip stacked on top, with a capping plate providing a receiving space for the upper sensor or microactuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple MEMS elements are assembled closely in the same package structure, then the package area is reduced, but signal interference between MEMS elements increases and yield and reliability are reduced
Solution Approach 1:
The patent transitions from a planar arrangement of MEMS elements to a three-dimensional stacked configuration. Multiple MEMS chips are vertically stacked with intermediate chips positioned between them, allowing closer integration while maintaining signal isolation through the vertical dimension and intermediate shielding layers.
Solution Approach 2:
Intermediate chips are introduced between the MEMS chips to serve as mediators. These intermediate chips include shielding layers and signal processing units that prevent direct signal interference between adjacent MEMS elements while enabling integrated control and readout functions.
2Adaptability or versatility
If additional controlling units are added to process signals from different MEMS elements, then signal integration is achieved, but the package area increases
Solution Approach 1:
The patent combines multiple functions into integrated intermediate chips that are stacked with MEMS chips. These intermediate chips integrate signal processing, control, and shielding functions, eliminating the need for separate controlling units and reducing overall package area while maintaining full signal integration capability.
Solution Approach 2:
The intermediate chips serve multiple functions simultaneously: they provide electromagnetic shielding between MEMS elements, process signals from multiple MEMS chips, perform control operations, and enable readout functions. This multi-functionality reduces the need for additional dedicated components.
3Area of stationary object
If MEMS chips are stacked vertically to reduce package area, then miniaturization is achieved, but signal interference between stacked chips increases
Solution Approach 1:
Intermediate chips with electromagnetic shielding layers are positioned between vertically stacked MEMS chips. These intermediate structures act as mediators that block electromagnetic interference between adjacent MEMS elements while maintaining the compact vertical stacking configuration.
Solution Approach 2:
The patent applies localized electromagnetic shielding at specific interfaces between MEMS chips through intermediate chips. Rather than shielding the entire package, shielding is applied locally where signal interference occurs between adjacent stacked elements, optimizing protection while minimizing impact on signal transmission.
Data Source
AI summary
A method for manufacturing package structure is provided, including: providing a substrate having recesses; forming first MEMS chips on the substrate, each with a through-substrate via, and a first sensor or microactuator on the lower surface, located in one of the recesses; forming first intermediate chips on the substrate, each respectively on one of the first MEMS chips, having a through-substrate via, and including a signal conversion unit, a logic operation unit, control unit, or a combination thereof; forming second MEMS chips on the first intermediate chips, each with a through-substrate via, having a second sensor or microactuator on its upper surface, wherein the package structure includes at least one of the first sensor and the second sensor; and forming first capping plates on the second MEMS chips, each providing a receiving space for the second sensor or microactuator on the upper surface of each second MEMS chip.