The Application of UV-LEDs to Microlithography

2008 ◽  
Author(s):  
Chen-Kang Huang ◽  
Jeng-Gang Sung
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Light Sources ◽  
Light Emitting ◽  
Uv Led ◽  
Line Process ◽  
Point Light ◽  
The Cost ◽  
Uv Leds ◽  
Light Beams

Benefited by the progress of material science, Light-Emitting Diodes (LED) with UV-emitting have been produced successfully. Like other LEDs, UV-LEDs exhibit several advantages, such as energy conservation, long life, compact, and quick response. The UV-LED application to microlithography is attractive. In contrast to point light sources requiring lens to generate parallel light beams, an array of UV-LEDs can emit nearly parallel light beams easily. UV-LEDs only need 3 to 4 voltages to ignite, which is much lower than that required by mercury short arc lamps. The cost of using UV-LEDs is also much lower than current solutions. In this study, we used UV-LEDs as the light source in the laboratory lithography system. LEDs, whose emitting spectrum distributed between 370 to 410 nm mostly, were displaced on the bottom of a heat sink. Two 10-by-10 cm2 test masks, where the smallest pattern was 20 μm, were used to examine the resolution ability of this combination. Each light module was utilized to exposure photosensitized printed circuit board (PCB). After etching, the printed patterns were observed under microscope. The minimum reproducible feature size was 100 μm. Through the 4” mask, the uniformity was decent, and could be improved by using LEDs from the same batch, collimator, or LED displacement optimization. In the future, standard g-line process can be performed, and further tests will be performed to check the limits of the UV-LED system. Based on these preliminary tests, it seems like the usage of UV-LEDs should be a feasible solution for microlithography.

Temperature and Humidity Dependent Reliability Analysis of RGB LED Chips

2006 ◽  
Author(s):  
Jun-Xian Fu ◽  
Shukri Souri ◽  
James S. Harris
Keyword(s):  
Reliability Analysis ◽  
Printed Circuit Board ◽  
Light Emitting Diode ◽  
Circuit Board ◽  
Light Emitting ◽  
Printed Circuit ◽  
Root Cause ◽  
Micro Cracks ◽  
Temperature And Humidity

Abstract Temperature and humidity dependent reliability analysis was performed based on a case study involving an indicator printed-circuit board with surface-mounted multiple-die red, green and blue light-emitting diode chips. Reported intermittent failures were investigated and the root cause was attributed to a non-optimized reflow process that resulted in micro-cracks and delaminations within the molding resin of the chips.

scholarly journals Compact Modelling of Electrical, Optical and Thermal Properties of Multi-Colour Power LEDs Operating on a Common PCB

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1286
Author(s):  
Krzysztof Górecki ◽  
Przemysław Ptak
Keyword(s):  
Integrated Circuits ◽  
Optical Model ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Junction Temperature ◽  
Optical Parameters ◽  
Spice Simulation ◽  
Light Emitting ◽  
Proposed Model ◽  
Good Agreement

This paper concerns the problem of modelling electrical, thermal and optical properties of multi-colour power light-emitting diodes (LEDs) situated on a common PCB (Printed Circuit Board). A new form of electro-thermo-optical model of such power LEDs is proposed in the form of a subcircuit for SPICE (Simulation Program with Integrated Circuits Emphasis). With the use of this model, the currents and voltages of the considered devices, their junction temperature and selected radiometric parameters can be calculated, taking into account self-heating phenomena in each LED and mutual thermal couplings between each pair of the considered devices. The form of the formulated model is described, and a manner of parameter estimation is also proposed. The correctness and usefulness of the proposed model are verified experimentally for six power LEDs emitting light of different colours and mounted on an experimental PCB prepared by the producer of the investigated devices. Verification was performed for the investigated diodes operating alone and together. Good agreement between the results of measurements and computations was obtained. It was also proved that the main thermal and optical parameters of the investigated LEDs depend on a dominant wavelength of the emitted light.

scholarly journals Wideband Rectangular Foldable and Non-foldable Antenna for Internet of Things Applications

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
Steve W. Y. Mung ◽  
Cheuk Yin Cheung ◽  
Ka Ming Wu ◽  
Joseph S. M. Yuen
Keyword(s):  
Internet Of Things ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Design Parameters ◽  
Multiple Frequency ◽  
Wireless Applications ◽  
Printed Circuit ◽  
Iot Applications ◽  
Trade Offs ◽  
The Cost

This article presents a simple wideband rectangular antenna in foldable and non-foldable (printed circuit board (PCB)) structures for Internet of Things (IoT) applications. Both are simple structures with two similar rectangular metal planes which cover multiple frequency bands such as GPS, WCDMA/LTE, and 2.4 GHz industrial, scientific, and medical (ISM) bands. This wideband antenna is suitable to integrate into the short- and long-range wireless applications such as the short-range 2.4 GHz ISM band and standard cellular bands. This lowers the overall size of the product as well as the cost in the applications. In this article, the configuration and operation principle are presented as well as its trade-offs on the design parameters. Simulated and experimental results of foldable and non-foldable (PCB) structures show that the antenna is suited for IoT applications.

Manufacture and Evaluation of Light Emitting Diode Package Substrate Using Flexible Printed Circuit Board

2015 ◽  
Vol 15 (10) ◽  
pp. 7578-7581
Author(s):  
Jung-Kab Park ◽  
Jin-Ha Shin ◽  
Mun-Gi Jung ◽  
Tomabechi Shigehisa ◽  
Hwa-Sun Park ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Light Emitting Diode ◽  
Thermal Conductance ◽  
Polyimide Film ◽  
Luminous Efficiency ◽  
Circuit Board ◽  
Light Sources ◽  
Thermal Shock Test ◽  
Light Emitting ◽  
Au Electrode

Unlike other light sources such as fluorescent lamps and incandescent bulbs, light-emitting diodes (LED) convert 70∼80% of energy into heat. If the heat produced an LED chip is not effectively released, its luminous efficiency and lifespan are reduced. Therefore, as a method effectively release heat, an LED PKG substrate containing a heat-releasing material with excellent thermal conductance was fabricated, and its thermal resistance and luminous efficiency were analyzed. In this experiment, a thin polyimide film with excellent ductility was used to fabricate the LED PKG substrate. A 35-μm-thick Cu foil with excellent thermal conductance was subjected to high temperature and pressure and attached to both sides of the polyimide film. By electroplating Ag or Au, which has excellent thermal conductance, for us as the electrode and heat-releasing material, LED PKG substrate was fabricated with a thickness of approximately 170 μm. (−40 °C → RT → 120 °C). The results revealed that the LED PKG substrate having a Ag electrode with excellent thermal conductance had an excellent thermal resistance of approximately 4.2 °C/W (Au electrode: 5.6 °C/W). The luminous flux after 100 cycles in the thermal shock test was reduced by approximately 0.09% (Au electrode: 2.77%), indicating that the LED PKG substrate had excellent thermal resistance without any mechanical and material defects in a rapid-temperature-changing environment. The advantages and excellent thermal resistance can be exploited in cellular phones and LCD panels, and heat-releasing problems in thin panels be solved.

ACCURATE MEASUREMENT OF ULTRAVIOLET LIGHT-EMITTING DIODES

2021 ◽  
Author(s):  
C. Yuqin Zong ◽  
Cameron Miller
Keyword(s):  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Luminous Flux ◽  
Junction Temperature ◽  
Integrating Sphere ◽  
Light Emitting ◽  
Type D ◽  
Uv Led ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes

We have developed a new calibration capability for 200 nm to 400 nm ultraviolet light-emitting diodes (UV LEDs) using a Type D gonio-spectroradiometer. The recently-introduced mean differential continuous pulse (M-DCP) method is used to overcome the measurement difficulty associated with the initial forward voltage, VF, anomaly of a UV LED, which makes it impossible to use VF to infer junction temperature, TJ, during pulsed operation. The new measurement facility was validated indirectly by comparing the measured total luminous flux of a white LED with that measured using the NIST’s 2.5 m absolute integrating sphere. The expanded calibration uncertainty for the total radiant flux is approximately 2 % to 3 % (k = 2) depending the wavelength of the UV LED.

scholarly journals 3D Microlithography Using an Integrated System of 5-mm UV-LEDs with a Tilt-Rotational Sample Holder

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 157 ◽  
Author(s):  
Sabera Fahmida Shiba ◽  
Hyeongmin Jeon ◽  
Jong-Soo Kim ◽  
Jong-Eun Kim ◽  
Jungkwun Kim
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Vertical Direction ◽  
Ultra Violet ◽  
Integrated System ◽  
Sample Holder ◽  
Large Area ◽  
Light Emitting ◽  
Uv Led ◽  
Uv Leds

This paper demonstrates a 3D microlithography system where an array of 5 mm Ultra Violet-Light Emitting Diode (UV-LED) acts as a light source. The unit of the light source is a UV-LED, which comes with a length of about 8.9 mm and a diameter of 5 mm. The whole light source comprises 20 × 20 matrix of such 5 mm UV-LEDs giving a total number of 400 LEDs which makes it a very favorable source with a large area for having a batch production of the desired microstructures. This light source is able to give a level of precision in microfabrication which cannot be obtained using commercial 3D printers. The whole light source performs continuous rotational movement once it is turned on. This can also move up and down in a vertical direction. This multidirectional light source also comprises a multidirectional sample holder. The light source teaming up with the multidirectional sample holder highly facilitates the process of fabrication of a huge range of 3D structures. This article also describes the different levels of characterization of the system and demonstrates several fabricated 3D microstructures including high aspect ratio vertical micro towers, twisted turbine structures, triangles, inclined pillar ‘V’ structures, and hollow horn structures as well.

scholarly journals Transcriptome and metabolome analyses revealed that narrowband 280 and 310 nm UV-B induce distinctive responses in Arabidopsis

2021 ◽  
Author(s):  
Tomohiro Tsurumoto ◽  
Yasuo Fujikawa ◽  
Daisaku Ohta ◽  
Atsushi Okazawa
Keyword(s):  
Anthocyanin Biosynthesis ◽  
Uv Light ◽  
Current Model ◽  
Phenylpropanoid Pathway ◽  
Metabolic Responses ◽  
Uv Resistance ◽  
Light Emitting ◽  
Uv Led ◽  
Uv Leds ◽  
Led Irradiation

SUMMARYIn plants, the UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8) perceives UV-B and induces UV-B responses including synthesis of UV-B absorbing phenolic compounds such as anthocyanins. UVR8 absorbs a range of UV-B (260–335 nm). However, the responsiveness of plants to each UV-B wavelength has not been intensively studied so far. Here, we performed transcriptome and metabolome analyses of Arabidopsis using UV light emitting diodes (LEDs) with peak wavelengths of 280 and 310 nm to investigate the differences in the wavelength-specific UV-B responses. Irradiation with both UV-LEDs induced gene expression of the transcription factor ELONGATED HYPOCOTYL 5 (HY5), which has a central role in the UVR8 signaling pathway. However, the overall transcriptomic and metabolic responses to 280 and 310 nm UV-LED irradiation were different. Most of the known UV-B-responsive genes, such as salicylic acid, jasmonic acid, and defense-related genes, responded only to 280 nm UV-LED irradiation. Lipids, polyamines and organic acids were the metabolites most affected by 280 nm UV-LED irradiation, whereas the effect of 310 nm UV-LED irradiation on the metabolome was considerably less. Enzymatic genes involved in the phenylpropanoid pathway upstream in anthocyanin biosynthesis were up-regulated only by 280 nm UV-LED irradiation. On the other hand, no enzymatic genes downstream in anthocyanin biosynthesis were induced by the UV-LEDs, but rather, they were down-regulated by 310 nm UV-LED irradiation. These results revealed that the responsivenesses of Arabidopsis to 280 and 310 nm UV-B were significantly different, suggesting that UV-B signaling is mediated by more complex pathways than the current model.

PENGARUH DIMENSI GEOMETRIK LAMPU LED TERHADAP PERSEPSI KECERAHAN

2013 ◽  
Vol 3 (2) ◽  
pp. 41
Author(s):  
Andrea Marisi ◽  
Revantino Revantino
Keyword(s):  
Solid State ◽  
Printed Circuit Board ◽  
Light Emitting Diode ◽  
Circuit Board ◽  
Solid State Lighting ◽  
Light Emitting ◽  
Printed Circuit ◽  
Surface Mounting

Perkembangan teknologi di bidang Solid State Lighting selama dekade terakhir membuat diversifikasi penggunaan Light Emitting Diode untuk pelayanan pencahayaan umum. Balai Besar Bahan dan Barang Teknik sejak tahun 2011 telah melakukan penelitian dan pengembangan lampu LED berbasis Surface Mounting Device (SMD) 5050. Pada perancangan Printed Circuit Board (PCB) untuk memasangkan LED-smd tersebut, dilakukan analisis dimensi geometrik yang optimal sehingga dapat memancarkan cahaya ke segala arah dan memberikan persepsi kecerahan yang lebih baik. Untuk perancangan PCB tersebut, dipilih 2 (dua) model berbentuk silinder dengan memperhatikan rasio antara tinggi dan diameter alas. Dari pendekatan sumber titik dan perhitungan eksitansi luminus, diperoleh bahwa model dengan rasio ≈ 1 menghasilkan persepsi lebih cerah terhadap visual manusia.Kata kunci : dimensi geometrik, pendekatan sumber titik, eksitansi luminus, persepsi kecerahan

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