CMUT Array Lamination Using Stamped Cavities for Fast Fabrication
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Solution Overview
Problem
Current methods for manufacturing capacitive micromachined ultrasonic transducers (CMUTs) are limited by slow production speed, require multiple fabrication steps on different equipment, use toxic chemicals, and are restricted in maximum array size, making them inefficient and environmentally harmful.
Innovation Solution
A method involving mechanical stamping of ultra-thin films and laminating them between metalized films to create cavities, eliminating wet chemical processing and overcoming size restrictions, allowing for faster and larger array production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional photolithography methods are used to fabricate CMUTs, then manufacturing precision can be achieved, but production speed is slow and array size is limited
Solution Approach 1:
The patent replaces the conventional photolithography process (optical/chemical system) with a mechanical stamping system. A stamping die mechanically impresses cavities into the polymer membrane, eliminating the need for photoresist, UV alignment, and chemical development. This mechanical approach enables faster production speeds while maintaining the required cavity precision through controlled stamping forces and die design.
Solution Approach 2:
The patent segments the CMUT fabrication into independent modular steps: stamping the cavity pattern into the polymer membrane, depositing metal electrodes on specific regions, and laminating layers together. This segmentation allows each step to be optimized independently and enables parallel processing of multiple arrays simultaneously, significantly increasing productivity without compromising precision.
2Productivity
If multiple fabrication steps on different equipment are used, then manufacturing precision is maintained, but device complexity increases and production time extends
Solution Approach 1:
The patent merges multiple separate fabrication steps into a single integrated stamping and lamination process. The cavity pattern is stamped directly into the polymer membrane while it is being laminated between substrate and electrode layers, combining what were previously separate operations (cavity formation, layer assembly, and bonding) into one simultaneous process. This reduces the number of equipment changes and process transitions, thereby reducing overall complexity and improving efficiency.
Solution Approach 2:
The patent performs preliminary actions by pre-pattern the metal electrodes on the polymer membrane before stamping the cavities, and by pre-preparing the stamping die with the exact cavity pattern needed. This allows the cavity formation to occur during the lamination process rather than requiring separate post-processing steps, reducing the total number of fabrication steps and equipment changes required.
3Object-affected harmful factors
If wet chemical processing is used in CMUT fabrication, then manufacturing precision is achieved, but harmful chemical waste is generated
Solution Approach 1:
The patent completely eliminates wet chemical processing by replacing the photolithography-based chemical etching process with a mechanical stamping process. The stamping die physically impresses cavities into the polymer membrane without requiring any chemicals, solvents, or development processes. This mechanical approach produces no chemical waste while maintaining the precise cavity dimensions needed for accurate CMUT fabrication.
Solution Approach 2:
The patent converts the potentially harmful wet chemical process into a beneficial dry mechanical process. By using mechanical stamping instead of chemical etching, the process eliminates toxic chemicals and waste while actually improving the cavity geometry control through direct mechanical imprinting. The 'harmful' chemical step is completely replaced by a clean mechanical action that is environmentally friendly and equally precise.
4Area of stationary object
If conventional fabrication methods are used, then process reliability is maintained, but array size is restricted
Solution Approach 1:
The patent transitions from fabricating small individual CMUTs to creating large-area arrays by changing the dimensional scale of the stamping process. The stamping die can be designed to pattern large areas of polymer membrane in a single pass, and multiple stamped membranes can be laminated together to form large arrays. This dimensional scaling approach enables the production of large arrays while maintaining process reliability through consistent mechanical stamping parameters.
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 enables high-speed, large-scale production of CMUTs without toxic chemicals, reducing environmental impact and expanding array size capabilities.
Implementation Method 1
contacting said material with a die comprising projections, the projections capable of puncturing said material to form shaped cavities in a pattern
Implementation Method 2
laminating said films by the addition of energy. The energy may come from heat and/or pressure.
Implementation Method 3
laminating said films by the addition of energy. The energy may come from heat and/or pressure.
Data Source
AI summary
Methods, systems, and techniques for the high speed manufacture of micro-electrical mechanical systems (MEMS) arrays, such as arrays of polymeric capacitive micromachined ultrasonic transducers (CMUTs). A sheet of material from which to form cavities for the devices is obtained, and physical or energy projections are projected into the material to form the cavities. Upper and lower surfaces of the material are respectively contacted with and bonded to upper and lower metalized films. The metalized portions of the upper and lower metalized films may serve as electrodes for a CMUT, and the films themselves may be the CMUT's substrate and membrane.