Microelectromechanical Microphone With Nested Control ASIC
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Solution Overview
Problem
The challenge lies in integrating microelectromechanical microphones with both high performance and reduced dimensions, particularly in portable and wearable devices, where fitting both a control ASIC and a microelectromechanical transducer in a package is difficult due to conflicting requirements of increasing transducer size for better performance and reducing overall size for compactness.
Innovation Solution
The solution involves a microelectromechanical microphone design where a sensor chip with a microelectromechanical acoustic transducer is bonded to a substrate, and a control chip is operatively coupled to the sensor chip, with both chips being housed within a package structure defined by a substrate and cap. The control chip is positioned in a through hole of the substrate, allowing for reduced thickness and area while maintaining acoustic communication through a sound port, and an adhesive layer or polymeric material is used for fixation, enabling efficient acoustic coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the size of the chip incorporating the control ASIC is increased to provide more control and processing functions, then the functionality and performance of the microphone is improved, but the overall dimensions of the package structure increase
Solution Approach 1:
The control ASIC chip is positioned within a through-hole of the substrate, nesting it within the existing package structure. This allows the chip to be housed inside the package footprint rather than requiring additional lateral space, thus providing enhanced control functions without increasing the overall package area.
Solution Approach 2:
The control ASIC is placed in a through-hole that extends through the substrate thickness, utilizing the vertical dimension (Z-axis) rather than lateral dimensions. This dimensional transition allows the chip to be accommodated within the existing package footprint by exploiting the depth dimension of the substrate.
2Reliability
If the size of the chip incorporating the microelectromechanical transducer is increased to improve acoustic performance, then the transduction performance is improved, but the overall dimensions of the package structure increase
Solution Approach 1:
The sensor chip containing the microelectromechanical transducer is bonded such that a first portion overlies and bonds to the control chip, while a second portion couples to the substrate base. This nested arrangement allows the transducer chip to utilize the vertical space above the control chip, providing enhanced acoustic performance without significantly increasing the lateral package footprint.
Solution Approach 2:
The sensor chip is arranged in a stacked configuration, utilizing the vertical dimension above the control chip rather than requiring additional lateral space. This allows the transducer to achieve improved acoustic performance through larger active area while maintaining a compact lateral footprint.
3Adaptability or versatility
If two chips (control ASIC and microelectromechanical transducer) are fitted in the package, then the functionality is improved, but the manufacturing complexity and difficulty of fitting increase
Solution Approach 1:
The microphone functionality is segmented into two separate chips: a control ASIC chip and a sensor chip containing the microelectromechanical transducer. This segmentation allows each chip to be optimized independently for its specific function, simplifying the design and manufacturing of each component while enabling enhanced overall functionality when integrated together.
Solution Approach 2:
The control ASIC chip is nested within a through-hole of the substrate, and the sensor chip is bonded to both the substrate and the control chip. This nested arrangement provides a structured integration approach that simplifies assembly by defining clear positioning and bonding interfaces, reducing manufacturing complexity despite having multiple chips.
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 design allows for reduced overall dimensions without increasing thickness, enabling larger chip dimensions for improved performance while maintaining efficient acoustic signal transduction, thus addressing the size and performance constraints in portable devices.
Implementation Method 1
The electroacoustic transducer converts incident acoustic waves, which cause vibrations of a membrane, into electrical signals. For example, the membrane may be capacitively coupled to a reference electrode.
Implementation Method 2
a first chip incorporating a microelectromechanical electroacoustic membrane transducer
Implementation Method 3
an adhesive layer or polymeric material is used for fixation, enabling efficient acoustic coupling
Data Source
AI summary
A microelectromechanical microphone includes: a substrate; a sensor chip, integrating a microelectromechanical electroacoustic transducer; and a control chip operatively coupled to the sensor chip. In one embodiment, the sensor chip and the control chip are bonded to the substrate, and the sensor chip overlies, or at least partially overlies, the control chip. In another embodiment, the sensor is bonded to the substrate and a barrier is located around at least a portion of the sensor chip.