MIM Capacitor Manufacturing via Selective Etching
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Solution Overview
Problem
There is a need for a cost-effective method to manufacture complimentary metal-insulator-metal (MIM) capacitors on a single chip that can address different circuit design requirements, including both low capacitance density, high voltage and high density capacitors, as existing technologies lack the capability to simultaneously produce these types for various applications such as power amplifiers and RF filters.
Innovation Solution
A method involving the deposition of multiple metal and dielectric layers in an interleaved pattern, followed by etching to form both low capacitance density, high voltage and high density MIM capacitors simultaneously, where the bottom plate of one capacitor serves as the top plate of the other, allowing for the creation of capacitors with a floating middle plate for high voltage applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate manufacturing processes are used for different types of MIM capacitors, then each capacitor type can be optimized for its specific requirements, but manufacturing complexity and cost increase
Solution Approach 1:
The patent implements a universal manufacturing process that can produce multiple types of MIM capacitors (high voltage and high density) using the same deposition and etching sequences. The process uses identical metal layer depositions and dielectric layer formations for both capacitor types, with differentiation achieved through selective etching patterns rather than separate process flows, thereby achieving multi-functionality in a single manufacturing line
Solution Approach 2:
The patent segments the capacitor structure into distinct regions on the same wafer, where different etch patterns create different capacitor types from the same underlying metal layers. The uppermost metal layer is selectively etched in different patterns for different capacitor regions, allowing high voltage capacitors to have exposed upper surfaces while high density capacitors have etched-away upper layers, creating functionally distinct devices from a unified structure
2Adaptability or versatility
If different MIM capacitor types are manufactured separately, then each type can be optimized for specific applications, but manufacturing cost and time increase
Solution Approach 1:
The patent merges the manufacturing of different capacitor types into a single integrated process flow. Both high voltage and high density MIM capacitors are formed simultaneously on the same wafer using the same metal layer depositions, dielectric layer formations, and etching sequences. The only differentiation step is selective etching of the uppermost metal layer in specific regions, allowing both capacitor types to be produced in the same manufacturing batch, thereby dramatically improving productivity and reducing per-unit costs
3Ease of manufacture
If standard semiconductor processes are used, then manufacturing cost is reduced, but the ability to create specialized capacitor structures may be limited
Solution Approach 1:
The patent applies local quality by using selective etching to create different capacitor structures in different regions of the wafer. The uppermost metal layer is etched away in high density capacitor regions while being protected or left intact in high voltage capacitor regions. This localized differentiation allows specialized structures to be created using standard deposition and etching processes, maintaining cost-effectiveness while achieving the adaptability needed for different circuit requirements
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
Enables the simultaneous formation of high quality factor, high voltage MIM capacitors with a floating middle plate, suitable for diverse circuit applications, using standard semiconductor processes like Cu or Al BEOL, thereby addressing the need for capacitors with varying capacitance densities.
Implementation Method 1
depositing a plurality of metal layers and dielectric layers in an interleaved pattern
Implementation Method 2
depositing a plurality of metal layers and dielectric layers in an interleaved pattern
Implementation Method 3
The etching includes etching a portion of an uppermost plate of the plurality of plates while protecting other portions of the uppermost plate
Implementation Method 4
The etching includes etching a portion of an uppermost plate of the plurality of plates while protecting other portions of the uppermost plate
Data Source
AI summary
A low capacitance density, high voltage MIM capacitor and the high density MIM capacitor and a method of manufacture are provided. The method includes depositing a plurality of plates and a plurality of dielectric layers interleaved with one another. The method further includes etching a portion of an uppermost plate of the plurality of plates while protecting other portions of the uppermost plate. The protected other portions of the uppermost plate forms a top plate of a first metal-insulator-metal (MIM) capacitor and the etching exposes a top plate of a second MIM capacitor.