MEMS Resonator Transducer Integration in CMOS Dielectric Layers
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Solution Overview
Problem
The challenge in creating MEMS resonator devices is the inefficiency of transducers in converting electrical signals to mechanical vibrations and vice versa, due to the difficulty in fabricating very fine gaps and the complexity of integrating MEMS devices with ICs using standard CMOS processes, which limits the capacitance and increases manufacturing costs.
Innovation Solution
A method for manufacturing a MEMS resonator device using the same device, dielectric, and conductive layers as in a CMOS process, where transducers are formed as capacitors with a dielectric plate and transducer plate from the dielectric and conductive layers, respectively, to enhance capacitance and efficiency without increasing complexity or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If MEMS devices are formed before or after standard foundry IC processing using high temperature oxidation, deposition, or both, then MEMS devices can be integrated with ICs on a single wafer, but the manufacturing process complexity and cost increase
Solution Approach 1:
The patent merges MEMS device formation with standard CMOS IC processing by using the same device layer, dielectric layer, and conductive layer for both MEMS resonator structures and transistor gates. This integration eliminates separate high temperature oxidation and deposition steps, reducing manufacturing complexity while maintaining the ability to create both MEMS and IC components on a single wafer
Solution Approach 2:
The dielectric layer and conductive layer serve dual purposes: they form the gate dielectric and gate electrode for CMOS transistors, and simultaneously create the dielectric plate and transducer plate for MEMS resonators. This multi-functionality eliminates the need for additional specialized processing steps for MEMS integration
2Reliability
If very fine gaps are required for MEMS resonators, then transducer efficiency can be improved, but fabrication difficulty increases significantly
Solution Approach 1:
The patent replaces mechanical gap formation techniques with a field-based approach where the dielectric layer thickness, controlled by standard CMOS deposition processes, determines the gap dimensions. This substitution of mechanical gap control with deposited layer thickness control eliminates the fabrication difficulties associated with creating very fine mechanical gaps while maintaining transducer efficiency
Solution Approach 2:
The patent changes the controlling parameter for gap dimension from mechanical etching depth to dielectric layer thickness, which can be precisely controlled through standard CMOS deposition processes. This parameter change enables precise gap control without the fabrication difficulties of mechanical methods
3Reliability
If the distance between transducer plate and resonator body is minimized to increase capacitance, then transducer effectiveness improves, but manufacturing complexity increases
Solution Approach 1:
The patent combines the formation of the dielectric plate and the minimization of distance between transducer plate and resonator body into a single step using the same dielectric layer deposition process. This eliminates additional processing steps that would be required to achieve minimal spacing, improving transducer effectiveness without increasing manufacturing complexity
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 simplifies the manufacturing process, reduces the footprint of semiconductor devices, and improves the efficiency of transducers by using a high dielectric constant dielectric layer and low resistive losses conductive layer, resulting in effective signal conversion and mechanical vibration in MEMS resonators.
Implementation Method 1
Each transducer is effectively a capacitor created by forming a dielectric plate between a transducer plate and the resonator body
Implementation Method 2
The dielectric plate is formed from the dielectric layer, which is also used to form the gate dielectric for the gate
Implementation Method 3
a common challenge remaining in creating a MEMS resonator device is the inability to construct transducers that will efficiently and effectively convert electrical signals to mechanical vibrations and vice versa
Data Source
AI summary
The present invention provides a method for manufacturing a micro-electro-mechanical system (MEMS) resonator device using the same device layer, dielectric layer, and conductive layer that is used to create other electrical devices in a complementary metal oxide semiconductor (CMOS) process.