Papers by Keyword: Photoresist

Abstract: Tetramethylammonium hydroxide (TMAH) and N-methyl pyrrolidinone (NMP) are commonly used in photoresist developing and stripping process, however, both of TMAH and NMP have been confirmed with CMR (Carcinogenic, Mutagenic and Reprotoxic) concerns. With more attention attracted to TMAH and NMP replacements, Huntsman developed a range of new quaternary amines products, including E-GRADE^® Choline OH (Choline Hydroxide), E-GRADE^® THEMAH (Tris (2-hydroxyethyl) methylammonium Hydroxide), XHE-125, XHE-128, XHE-138, XHE-145 and XHE-148, and solvents, E-GRADE^® MEOX (3-Methyl-2-oxazolidinone) and XHE-123, which have been evaluated in comparison with the performance of TMAH and NMP.

Abstract: Photoresist after implantation is commonly removed either by wet chemical dissolution with sulfuric acid, or by dry ash stripping followed with a wet cleaning. To prevent any photoresist residues, sulfuric acid is still conserved in post ash cleans as additional safety. However, by ensuring sufficient over ash time, SPM (Sulfuric acid Peroxide hydrogen Mixture) chemical need becomes less essential. This paper reevaluates the benefit of SPM after dry ash stripping regarding the environmental context. The advantages of dry ash stripping with clean, compared to wet stripping are outlined. The study introduces prior analyses on defectivity and material consumption. Finally, device matching and yield stability, defined as the main success criteria, are described.

Abstract: Semiconductor component and microelectromechanical system manufacturing requires metal patterning in an integrated circuit (IC), using the photoresist lift-Off process. Ideal advantages like cost-effectiveness, reduction of complexity and process maturity are associated with the lift-Off process. Alternatively, the choice of photoresist relies on factors such as cost, initial photoresist thickness and reliable processing parameters extraction. However, the availability of the cheap photoresist is still at question. For the case of the underlying study, a highly cheap photoresist E8015 of thickness 38-micrometer was developed for the purpose of edge profiling. Desirable extraction of the useful parameter range for dry resist processing is performed. Parameter variation like exposure energy and development time led to a successful undercut angle of 66° to 73°, while the straight edge profile of 90° was realized at various parameter combinations. Eventually, a metallic multilayer of 10-micrometer thickness is successfully lifted off on plain silicon. Controlled self-propagating reaction within these structured metallic layers may be employed for IC packaging hereafter.

Abstract: The article discusses the technological process for MEMS sensors manufacturing, which provides the minimum allowable technological defects to achieve MEMS technical characteristics. The paper deals with experiments on the definition of technological operations and the choice of their parameters. The factors influencing the size of technological defects are revealed. There is a technology to manufacture MEMS considered as "silicon on glass." There were successful experiments with the use of mask thickness of 540 nm and 450 nm. The slope of the faces does not exceed 1o, the maximum height of the surface roughness profile was 75 nm.

Abstract: In this paper we presented the synthesis of TEOS with photoresist in order to use it like a hybrid material for 3D printer on the micrometer scale by means of the two-photon polymerization process, in which two photon are absorbed simultaneously by the material using an ultrafast laser causing its polymerization. We analyzed the mix of TEOS and photoresist with UV-VIS and FTIR spectrometers, checking that complies with two important conditions: has an optical transmission at 780 nm and absorbs at 390 nm. Finally we fabricated micro-structures with a new hybrid material; TEOS does not absorb the laser in this system and does not interfere with the formation of a three-dimensional structure. After formation the 3D microstructure, samples were heated to form the SiO. These samples of microstructures were observed under digital microscope and SEM.

Abstract: With the increase of implantation dose in new technologies, implanted photoresist stripping is even more challenged in terms of efficiency and substrate consumption. In this work, the effect of implantation parameters (energy and implanted specie) on the photoresist modifications are studied and several plasma chemistries are evaluated to remove it. A good removal efficiency with a low substrate consumption has been found with H₂-based processes especially N₂H₂.

Abstract: Periodic nanohole pattern was created in spin-coated photoresist S1805 on Si substrates by Laser Interference Lithography (LIL). Wavelength of a laser source used in the optical system is 442 nm with the photon energy 2.80 eV. The system was set up to employ two laser beams from a beam splitter to generate interference pattern and expose to the photoresist. There are two parameters (incident angle and exposure time) which are determined due to affecting the ordering and feature of nanohole array. Therefore, the relation of these two parameters and actual dose were investigated and theoretically analyzed to optimize the resolution of LIL technique for nanoholes. The prepared samples after developing in the M26A for 5 sec were analyzed by field-emission scanning electron microscopy (FE-SEM). The results show that the pitch of the pattern is 440 nm and the smallest hole size is 190 nm The best feature is found for a laser fluence of 140 mJ/cm². This nanohole array patterned by LIL consists of periodic nanostructures for high density storage to fabricate various nanodevices.

Abstract: Photoresist used in the fabrication of Microelectrochemical Systems (MEMS) has traditionally been processed using conventional curing technology. This type of curing is often time intensive and results in non-uniform products. A uniform bake of the layer is not always possible due to the mechanisms of heat transfer conventional curing offers, leading to poor pattern resolution, formation of micro-cracks and severe outgassing occurring as a consequence. The Variable Frequency Microwave (VFM) Technique was successfully utilised in this study as an alternative method for the processing of negative tone SU8 photoresist. The VFM method was compared to the conventional processing method, which utilises a Hotplate, and a hybrid method utilizing both Hotplate and the VFM and found that an increase on the degree of cure was observed using the VFM at similar processing temperatures which means that SU8 curing at lower temperatures or rapid curing is possible. The increase in cure rates can be attributed to a combination of heat transfer and the unique capability of microwave to couple with the sample. Optical studies of the microstructures fabricated suggest that films that have a degree of cure of <60% resulted in poor quality microstructures. The VFM was found to achieve satisfactory microstructures at most of the temperatures tested as compared to the other two methods tested.

Abstract: The fabrication of sensitive and selective nanodevices is one of the important challenges for future detection of low concentration single bio molecule. The current research article is one of the attempts to achieve such sensitive and selective micro-gap electrodes by simple, low cost controllable process. Therefore high sensitive chrome mask was designed for micro-gap design transformation to wafer samples. At first the positive photoresist namely PR-1 2000A was spin coated on the samples wafer at different rotation speed. Then by implementation of low cost conventional photolithography technique an initial structure of micro-gap was patterned on wafer sample. Finally by using surface Nanoprofiler the thickness of resist coated wafer samples were investigated. The obtained results show that the thickness of the resist is directly related with spin coating speed of spin coater.

Abstract: For a submicron photolithography process, there is little room for error. In this paper, an optimized technique for photoresist (PR) development is reported, to fabricate a nanogap biosensor for application in biomedical nanodiagnostics. The pattern transfer on the wafer substrate requires precise alignment and Deep Ultra-Violet (DUV) light exposure. This research describes the photolithography process to develop a standard manufacturing procedure for pattern transfer from chrome mask. The key factor for PR development is understood and the optimization is done based on the PR thickness, spin speed, spin time, exposure time, post-exposure bake (PEB) time, developer concentration and developing time to achieve the design feature size of 1 micron. The PR is coated and spun at 3000 rpm and 5000 rpm at 30s and 40s respectively to form a very thin layer. However, the UV exposure time is remained constant at 10s. After the pattern transfer, the wafer is immersed in different concentrations of RD6 developer to develop the PR. To further improve the resolution of image transfer, the PEB time is also optimized for a better throughput on feature size. These optimizations are important to reduce the dimension error and were able to achieve error free design to protect critical dimension and prevent device failure.