Abstract

We explored an alternative light emitting diode (LED) - based solution to replace the existing yellow fluorescent light tubes (YFT) used in photolithography rooms. A no-blue LED lamp was designed and a prototype was fabricated. For both solutions, the spectral power distribution (SPD) was measured, the colorimetric values were calculated, and a visual comparison using Gretagmacbeth colorcharts was performed. The visual comparison showed that the LED bulb was better to render colors despite a low color rendering index (CRI). Furthermore, the LED bulb was tested in a photolithography room and there was no exposure to the photoresist even after 168 hours illumination.

© 2009 Optical Society of America

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References

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  1. A. G. Baca and C. I. H. Ashby, Fabrication of GaAs Devices, (Institution of Electrical Engineers, 2005). pp. 129-132.
  2. Tel Aviv University, "Yellow Room (2009)," http://www.tau.ac.il/~srichter/images/lab/yellowroom.JPG
  3. M. C. Breadmore, and R. M. Guijt, "High intensity light emitting diode array as an alternative exposure source for the fabrication of electrophoretic microfluidic devices," J. Chromaticy A, 3-7 (2008).
    [CrossRef]
  4. Clariant, "Data Sheet: AZ5214E (2009)," http://www.first.ethz.ch/infrastructure/Chemicals/Photolithography/DataAZ5214E.pdf.
  5. Clariant, "Data Sheet: AZ4500 (2009)," http://www.first.ethz.ch/infrastructure/Chemicals/Photolithography/DataAZ4500.pdf.
  6. Clariant, "Data Sheet: AZ1500 (2009)," http://www.first.ethz.ch/infrastructure/Chemicals/Photolithography/DataAZ1500.pdf.
  7. Clariant, "Data Sheet: AZ4000 (2009)," http://www.azem.com/PDFs/p4000/azp4000.pdf.
  8. micro resist technology, "Product Information: Negative Tone Photoresist ma-N 400 (2009)," http://www.first.ethz.ch/infrastructure/Chemicals/Photolithography/DatamaN400.pdf.
  9. micro resist technology, "Product Information: Negative Tone Photoresist ma-N 1400 (2009)," http://www.first.ethz.ch/infrastructure/Chemicals/Photolithography/Data maN1400.pdf.
  10. micro resist technology, "Product Information: Negative Tone Photoresist ma-N 2400 (2009)," http://www.first.ethz.ch/infrastructure/Chemicals/Photolithography/DatamaN2400.pdf.
  11. Shipley, "Microposit S1800 series Photo Resist (2009)," http://www.camd.lsu.edu/microfabrication/cleanroomchemicals/Shipley1800Series.pdf.
  12. Shipley, "i-line Photoresist, Megaposit SPR220 series Photoresist (2009)," http://www.ece.neu.edu/groups/mfl/reference/photoprocess/SPR220DataSheet.pdf.
  13. Microchem, "Permanent Epoxy Negative Photoresist: SU-8 2100 and SU-8 2150 (2009)," http://www.microchem.com/products/pdf/SU82000DataSheet2100and2150Ver5.pdf.
  14. Microchem, "Permanent Epoxy Negative Photoresist: SU-8 2000.5, SU-8 2002, SU-8 2005, SU-8 2007, SU-8 2010 and SU-8 2015 (2009)," http://www.microchem.com/products/pdf/SU82000DataSheet20005thru2015Ver4.pdf.
  15. Microchem, "Permanent Epoxy Negative Photoresist: SU-8 2025, SU-8 2035, SU-8 2050 and SU-8 2075 (2009)," http://www.microchem.com/products/pdf/SU82000DataSheet2025thru2075Ver4.pdf.
  16. Microchem, "KMPR 1000: Chemical Amplified Negative Photoresist (2009)," http://www.microchem.com/products/pdf/KMPRDataSheetver42a.pdf.
  17. E. Fred Schubert, "Light-Emitting Diodes.," (Cambridge University Press, United Kingdom, 2008).
  18. CIE, "Method of Measuring And Specifying Colour Rendering Properties Of Light Sources," CIE 13.3-1995 (1995).
  19. Labsphere, "Method of Measuring And Specifying Colour Rendering Properties Of Light Sources,"
  20. Pike Technologies (2005), "Integrating Spheres - Introduction and Theory,"
  21. N. Koren, "Color management (2009)," http://www.normankoren.com/color management 2A.html.
  22. N. Koren, "ColorChecker (2009)," http://www.normankoren.com/ColorCheckersRGB.jpg.
  23. R. A. Young, "Porphyria skin disease (2009)," http://visionscience.com/mail/cvnet/1995/0339.html.

2008 (1)

M. C. Breadmore, and R. M. Guijt, "High intensity light emitting diode array as an alternative exposure source for the fabrication of electrophoretic microfluidic devices," J. Chromaticy A, 3-7 (2008).
[CrossRef]

Breadmore, M. C.

M. C. Breadmore, and R. M. Guijt, "High intensity light emitting diode array as an alternative exposure source for the fabrication of electrophoretic microfluidic devices," J. Chromaticy A, 3-7 (2008).
[CrossRef]

Guijt, R. M.

M. C. Breadmore, and R. M. Guijt, "High intensity light emitting diode array as an alternative exposure source for the fabrication of electrophoretic microfluidic devices," J. Chromaticy A, 3-7 (2008).
[CrossRef]

J. Chromaticy A (1)

M. C. Breadmore, and R. M. Guijt, "High intensity light emitting diode array as an alternative exposure source for the fabrication of electrophoretic microfluidic devices," J. Chromaticy A, 3-7 (2008).
[CrossRef]

Other (22)

Clariant, "Data Sheet: AZ5214E (2009)," http://www.first.ethz.ch/infrastructure/Chemicals/Photolithography/DataAZ5214E.pdf.

Clariant, "Data Sheet: AZ4500 (2009)," http://www.first.ethz.ch/infrastructure/Chemicals/Photolithography/DataAZ4500.pdf.

Clariant, "Data Sheet: AZ1500 (2009)," http://www.first.ethz.ch/infrastructure/Chemicals/Photolithography/DataAZ1500.pdf.

Clariant, "Data Sheet: AZ4000 (2009)," http://www.azem.com/PDFs/p4000/azp4000.pdf.

micro resist technology, "Product Information: Negative Tone Photoresist ma-N 400 (2009)," http://www.first.ethz.ch/infrastructure/Chemicals/Photolithography/DatamaN400.pdf.

micro resist technology, "Product Information: Negative Tone Photoresist ma-N 1400 (2009)," http://www.first.ethz.ch/infrastructure/Chemicals/Photolithography/Data maN1400.pdf.

micro resist technology, "Product Information: Negative Tone Photoresist ma-N 2400 (2009)," http://www.first.ethz.ch/infrastructure/Chemicals/Photolithography/DatamaN2400.pdf.

Shipley, "Microposit S1800 series Photo Resist (2009)," http://www.camd.lsu.edu/microfabrication/cleanroomchemicals/Shipley1800Series.pdf.

Shipley, "i-line Photoresist, Megaposit SPR220 series Photoresist (2009)," http://www.ece.neu.edu/groups/mfl/reference/photoprocess/SPR220DataSheet.pdf.

Microchem, "Permanent Epoxy Negative Photoresist: SU-8 2100 and SU-8 2150 (2009)," http://www.microchem.com/products/pdf/SU82000DataSheet2100and2150Ver5.pdf.

Microchem, "Permanent Epoxy Negative Photoresist: SU-8 2000.5, SU-8 2002, SU-8 2005, SU-8 2007, SU-8 2010 and SU-8 2015 (2009)," http://www.microchem.com/products/pdf/SU82000DataSheet20005thru2015Ver4.pdf.

Microchem, "Permanent Epoxy Negative Photoresist: SU-8 2025, SU-8 2035, SU-8 2050 and SU-8 2075 (2009)," http://www.microchem.com/products/pdf/SU82000DataSheet2025thru2075Ver4.pdf.

Microchem, "KMPR 1000: Chemical Amplified Negative Photoresist (2009)," http://www.microchem.com/products/pdf/KMPRDataSheetver42a.pdf.

E. Fred Schubert, "Light-Emitting Diodes.," (Cambridge University Press, United Kingdom, 2008).

CIE, "Method of Measuring And Specifying Colour Rendering Properties Of Light Sources," CIE 13.3-1995 (1995).

Labsphere, "Method of Measuring And Specifying Colour Rendering Properties Of Light Sources,"

Pike Technologies (2005), "Integrating Spheres - Introduction and Theory,"

N. Koren, "Color management (2009)," http://www.normankoren.com/color management 2A.html.

N. Koren, "ColorChecker (2009)," http://www.normankoren.com/ColorCheckersRGB.jpg.

R. A. Young, "Porphyria skin disease (2009)," http://visionscience.com/mail/cvnet/1995/0339.html.

A. G. Baca and C. I. H. Ashby, Fabrication of GaAs Devices, (Institution of Electrical Engineers, 2005). pp. 129-132.

Tel Aviv University, "Yellow Room (2009)," http://www.tau.ac.il/~srichter/images/lab/yellowroom.JPG

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Figures (11)

Fig. 1.
Fig. 1.

A typical photolithography room illuminated by a yellow fluorescent light tube [2].

Fig. 2.
Fig. 2.

Some typical LED spectra, the spectral bandwidth ranges from 20 nm (Red LEDs) to 40 nm (Green LEDs). The LEDs measured are from the supplier “KingBright”.

Fig. 3.
Fig. 3.

The LED Bulb prototype used in the experiments, it was created by RGB Lamps.

Fig. 4.
Fig. 4.

The measurement setup; The LED bulb were located inside the darkroom, the spectra were collected by an integrated sphere and transferred to the spectrometer. The spectrometer used a 300 l/mm grating yielding a spectral measurement range from 270.6 nm to 838.7 nm, with a resolution of around 0.6 nm.

Fig. 5.
Fig. 5.

A simulated “ColorChecker” chart from Gretagmacbeth, typically used when comparing different illumination sources with each other. [22]

Fig. 6.
Fig. 6.

The spectral power distribution of the LED bulb, measured at a steady state.

Fig. 7.
Fig. 7.

The spectrum of the yellow fluorescent light tube, measured at a steady state.

Fig. 8.
Fig. 8.

The CIE 1960 (u,v)-uniform chromatic coordinate system including the uniform chromatic coordinates of the LED bulb, the yellow fluorescent light tube, the planckian locus and some typical LED locations.

Fig. 9.
Fig. 9.

The color rendering for the 14 different Color rendering indices used when calculating the color rendering index, for a normal incandescent light bulb (CRI 99.9), the YFT (CRI 30.4) and the LED bulb (CRI 12.59).

Fig. 10.
Fig. 10.

Photographs of the Gretagmacbeth color rendition chart illuminated by a) an incandescent light bulb, b) the yellow fluorescent light tube and c) the LED bulb.

Fig. 11.
Fig. 11.

A microscope image of a fraction of the patterns used on the mask.

Tables (2)

Tables Icon

Table 1. Different types of photoresists and their wavelength sensitivity [416].

Tables Icon

Table 2. The colorimetric values of the LED bulb and the yellow fluorescent light tube.

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