Embedded IC in MEMS Microphone PCB for Size Reduction
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Solution Overview
Problem
The size reduction of MicroElectroMechanical System (MEMS) devices, such as microphones, is hindered by the significant size of integrated circuits mounted on printed circuit boards, which limits their miniaturization in applications like cellular phones and headsets.
Innovation Solution
Embedding an integrated circuit within the printed circuit board of MEMS devices, allowing the MEMS die to be mounted over the integrated circuit, with signals routed through plated through hole vias to the outer metallization layer, enabling a more compact design and acoustic sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the integrated circuit is mounted on the printed circuit board, then the electrical connections and signal processing are achieved, but the device size increases
Solution Approach 1:
The integrated circuit is embedded within a cavity formed in the printed circuit board, nesting one component (IC) inside the structure of another (PCB). This allows the IC to be housed within the PCB footprint rather than occupying additional board area, resolving the contradiction between reliable electrical connections and minimized device footprint.
Solution Approach 2:
The solution transitions from a two-dimensional surface mounting approach to a three-dimensional embedded approach. By creating a cavity and embedding the IC vertically within the PCB structure, the design utilizes the Z-dimension (depth) to accommodate the IC, thereby reducing the X-Y plane footprint while maintaining all necessary electrical connections through vias and conductors.
2Volume of moving object
If the integrated circuit size is reduced, then the device miniaturization is improved, but the circuit functionality may be compromised
Solution Approach 1:
The embedded integrated circuit approach allows for optimized local routing and connection structures. The PCB can be designed with specific via patterns, conductor traces, and cavity dimensions tailored to the exact requirements of the embedded IC, ensuring that each local area provides the optimal electrical and mechanical properties for that specific component, thereby maintaining functionality while reducing overall volume.
Data Source
AI summary
A Microelectromechanical System (MEMS) microphone includes a printed circuit board, a MEMS die, and an integrated circuit. The MEMS die is disposed on a top surface of the printed circuit board. The integrated circuit is disposed at least partially within the printed circuit board and produces at least one output signal. The output signals of the integrated circuit are routed directly into at least one conductor to access pads at the printed circuit board and the access pads are disposed on a bottom surface of the printed circuit board that is opposite the top surface.