Extreme ultraviolet lithography (EUVL) is widely seen as a key technology for future semiconductor mass production. However, due to the short wavelength material properties of EUV, it is strongly absorbed by most materials. Thus if the shutter for a lithography system operates by means of absorption, one must consider the potential temperature rise due to the high energy radiation absorbed by the structure. In this paper, we propose using a high-reflectance shutter so as to resolve temperature-related precision problems in lithography systems. A single-layer molybdenum film is used to greatly reduce the quantity of absorbed radiation energy by the shutter structure (in line with Fresnel equation) by increasing the incidence angle. A green laser is used as the light source to construct an automatic measuring system for reflectance and transmittance to verify the increase of material reflectance by the incidence angle of the photosource. The obtained incidence angle is also be fixed on the multilayered piezoelectric to serve as an actuator, so as to measure the high-frequency echoed signal of the laser photosource. Results show that, when the incidence angle is 83°, the optimum energy reflectance (50%) is obtained and the switching frequency reaches a maximum of 19 kHz, verifying the feasibility of using the reflected energy as the photosource switch. Finally, experiments were conducted in Taiwan’s National Synchrotron Radiation Research Center (NSRRC) using EUV as the photosource to measure the reflectance curves of single-layer molybdenum and aluminum films with different thicknesses under different incidence angles. Experimental results show that a high degree of reflection can be produced by the proposed single-layer film structure given a large incidence angle. The reflectance also increased significantly at an incidence angle of 60° for molybdenum while 70° for aluminum, and this relatively high reflection by molybdenum with a smaller incidence angle can be used to facilitate lithography system construction
We present a fully-packaged acoustic power receiver which is implantable in the subcutaneous tissue to receive the acoustic energy generated from a compressive wave emitter on the skin. The implanted receiver is a piezoelectric acoustic transducer and is packaged by biocompatible cohesive gels. This specific package is soft enough to absorb the incident wave from the subcutaneous tissue. The receiver employs direct charging to convert the acoustic energy into the extractable electrical energy through piezoelectricity when exposed to the acoustic field. The effects of the scattering package shape and the stiffness ratio between the package and subcutaneous tissue are considered to design the receivers. The energy efficiency of the fabricated receiver is measured inside real streaky pork, which is used to simulate human subcutaneous tissue. The result indicates that the spherical package is more suitable than the cubic one when they are buried in the fatty layer. The maximum efficiency of the power transmission is found to be -40dB.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.