MEMS Variable Capacitance and MIM Capacitor Insulator Thickness
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Solution Overview
Problem
The challenge lies in simultaneously forming MEMS variable capacitance elements and MIM capacitance elements with specific insulator characteristics in the same manufacturing process, as they require different insulator thicknesses and dielectric constants, making it difficult to achieve the desired characteristics for both without increasing the complexity and cost of the manufacturing process.
Innovation Solution
The solution involves forming MEMS devices with a MEMS element having a first insulator thickness and a MIM capacitance element with a second insulator thickness less than the first, achieved by etching the insulator on the MIM capacitance element while maintaining the thickness of the insulator on the MEMS element, and using high-dielectric constant materials for the MIM capacitance element to enhance capacitance, while ensuring the MEMS element's insulator remains thick to reduce electric field effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick insulator is used in MEMS variable capacitance element to reduce electric field effects, then reliability is improved, but capacitance value is reduced
Solution Approach 1:
The patent applies local quality by differentiating insulator thickness for different elements: the MEMS variable capacitance element uses a first insulator thickness (first insulating film) while the MIM capacitance element uses a second insulator thickness (second insulating film) that is thinner. This allows each element to have optimized insulator characteristics tailored to its specific functional requirements, resolving the contradiction between reliability and capacitance value.
2Quantity of substance
If a thin insulator is used in MIM capacitance element to increase capacitance, then capacitance value is improved, but electric field effects increase
Solution Approach 1:
The patent implements local quality by assigning different insulator thicknesses to different capacitance elements based on their functional requirements. The MIM capacitance element uses a thinner second insulating film to achieve high capacitance, while the MEMS variable capacitance element uses a thicker first insulating film to minimize electric field effects. This localized differentiation resolves the contradiction between capacitance value and electric field effects.
3Reliability
If different insulator characteristics are used for MEMS and MIM elements, then element performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the insulator structure into two distinct insulating films: a first insulating film for the MEMS variable capacitance element and a second insulating film for the MIM capacitance element. This segmentation allows each element to have optimized insulator characteristics while maintaining a unified manufacturing process, thus improving element performance without significantly increasing manufacturing complexity.
Solution Approach 2:
The patent demonstrates universality by using the same manufacturing process to form both the first and second insulating films simultaneously. The process forms a stacked insulator structure where the first insulating film serves the MEMS element and the second insulating film serves the MIM element, achieving differentiated insulator characteristics through a universal manufacturing approach that does not require separate processing steps.
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 allows for improved reliability and characteristics of both MEMS and MIM elements, reducing manufacturing complexity and costs by maintaining distinct insulator thicknesses and using high-dielectric materials, thereby enhancing capacitance and reducing electric field noise.
Implementation Method 1
forming a second insulator having a second thickness less than the first thickness on the second lower electrode, by etching the exposed first insulator through the second opening
Data Source
AI summary
A MEMS device of an aspect of the present invention including a MEMS element includes a first lower electrode provided on a substrate, a first insulator which is provided on the upper surface of the first lower electrode, and has a first thickness, and a movable first upper electrode supported by an anchor in midair above the first lower electrode, and a capacitance element includes a second lower electrode provided on the substrate, a second insulator which is provided on the upper surface of the second lower electrode, and has a second thickness, and a second upper electrode provided on the second insulator, wherein the second thickness is less than the first thickness.