Fabrication method to create high-aspect ratio pillars for photonic coupling of board level interconnects

C. Debaes, J. Van Erps, Mikko Karppinen, Jussi Hiltunen, H. Suyal, A. Last, M. G. Lee, Pentti Karioja, M. Taghizadeh, J. Mohr, H. Thienpont, A. L. Glebov

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

2 Citations (Scopus)

Abstract

An important challenge that remains to date in board level optical interconnects is the coupling between the optical waveguides on printed wiring boards and the packaged optoelectronics chips, which are preferably surface mountable on the boards. One possible solution is the use of Ball Grid Array (BGA) packages. This approach offers a reliable attachment despite the large CTE mismatch between the organic FR4 board and the semiconductor materials. Collimation via micro-lenses is here typically deployed to couple the light vertically from the waveguide substrate to the optoelectronics while allowing for a small misalignment between board and package. In this work, we explore the fabrication issues of an alternative approach in which the vertical photonic connection between board and package is governed by a micro-optical pillar which is attached both to the board substrate and to the optoelectronic chips. Such an approach allows for high density connections and small, high-speed detector footprints while maintaining an acceptable tolerance between board and package. The pillar should exhibit some flexibility and thus a high-aspect ratio is preferred. This work presents and compares different fabrication methods and applies different materials for such high-aspect ratio pillars. The different fabrication methods are: photolithography, direct laser writing and deep proton writing. The selection of optical materials that was investigated is: SU8, Ormocers, PU and a multifunctional acrylate polymer. The resulting optical pillars have diameters ranging from 20um up to 80um, with total heights ranging between 30um and 100um (symbol for micron). The aspect-ratio of the fabricated structures ranges from 1.5 to 5.
Original languageEnglish
Title of host publicationMicro-Optics 2008
DOIs
Publication statusPublished - 2008
MoE publication typeA4 Article in a conference publication
EventMicro-Optics 2008: SPIE Photonics Europe - Strasbourg, France
Duration: 4 Apr 20084 Apr 2008

Publication series

SeriesProceedings of SPIE
Volume6992

Conference

ConferenceMicro-Optics 2008
CountryFrance
CityStrasbourg
Period4/04/084/04/08

Fingerprint

high aspect ratio
photonics
fabrication
chips
optical interconnects
wiring
collimation
footprints
optical materials
photolithography
acrylates
optical waveguides
misalignment
attachment
aspect ratio
balls
flexibility
grids
lenses
high speed

Keywords

  • Deep proton writing
  • Direct laser writing
  • Micro-fabrication
  • Optical interconnects
  • UV-lithography

Cite this

Debaes, C., Van Erps, J., Karppinen, M., Hiltunen, J., Suyal, H., Last, A., ... Glebov, A. L. (2008). Fabrication method to create high-aspect ratio pillars for photonic coupling of board level interconnects. In Micro-Optics 2008 Proceedings of SPIE, Vol.. 6992 https://doi.org/10.1117/12.782721
Debaes, C. ; Van Erps, J. ; Karppinen, Mikko ; Hiltunen, Jussi ; Suyal, H. ; Last, A. ; Lee, M. G. ; Karioja, Pentti ; Taghizadeh, M. ; Mohr, J. ; Thienpont, H. ; Glebov, A. L. / Fabrication method to create high-aspect ratio pillars for photonic coupling of board level interconnects. Micro-Optics 2008. 2008. (Proceedings of SPIE, Vol. 6992).
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title = "Fabrication method to create high-aspect ratio pillars for photonic coupling of board level interconnects",
abstract = "An important challenge that remains to date in board level optical interconnects is the coupling between the optical waveguides on printed wiring boards and the packaged optoelectronics chips, which are preferably surface mountable on the boards. One possible solution is the use of Ball Grid Array (BGA) packages. This approach offers a reliable attachment despite the large CTE mismatch between the organic FR4 board and the semiconductor materials. Collimation via micro-lenses is here typically deployed to couple the light vertically from the waveguide substrate to the optoelectronics while allowing for a small misalignment between board and package. In this work, we explore the fabrication issues of an alternative approach in which the vertical photonic connection between board and package is governed by a micro-optical pillar which is attached both to the board substrate and to the optoelectronic chips. Such an approach allows for high density connections and small, high-speed detector footprints while maintaining an acceptable tolerance between board and package. The pillar should exhibit some flexibility and thus a high-aspect ratio is preferred. This work presents and compares different fabrication methods and applies different materials for such high-aspect ratio pillars. The different fabrication methods are: photolithography, direct laser writing and deep proton writing. The selection of optical materials that was investigated is: SU8, Ormocers, PU and a multifunctional acrylate polymer. The resulting optical pillars have diameters ranging from 20um up to 80um, with total heights ranging between 30um and 100um (symbol for micron). The aspect-ratio of the fabricated structures ranges from 1.5 to 5.",
keywords = "Deep proton writing, Direct laser writing, Micro-fabrication, Optical interconnects, UV-lithography",
author = "C. Debaes and {Van Erps}, J. and Mikko Karppinen and Jussi Hiltunen and H. Suyal and A. Last and Lee, {M. G.} and Pentti Karioja and M. Taghizadeh and J. Mohr and H. Thienpont and Glebov, {A. L.}",
year = "2008",
doi = "10.1117/12.782721",
language = "English",
series = "Proceedings of SPIE",
publisher = "International Society for Optics and Photonics SPIE",
booktitle = "Micro-Optics 2008",

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Debaes, C, Van Erps, J, Karppinen, M, Hiltunen, J, Suyal, H, Last, A, Lee, MG, Karioja, P, Taghizadeh, M, Mohr, J, Thienpont, H & Glebov, AL 2008, Fabrication method to create high-aspect ratio pillars for photonic coupling of board level interconnects. in Micro-Optics 2008. Proceedings of SPIE, vol. 6992, Micro-Optics 2008, Strasbourg, France, 4/04/08. https://doi.org/10.1117/12.782721

Fabrication method to create high-aspect ratio pillars for photonic coupling of board level interconnects. / Debaes, C.; Van Erps, J.; Karppinen, Mikko; Hiltunen, Jussi; Suyal, H.; Last, A.; Lee, M. G.; Karioja, Pentti; Taghizadeh, M.; Mohr, J.; Thienpont, H.; Glebov, A. L.

Micro-Optics 2008. 2008. (Proceedings of SPIE, Vol. 6992).

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

TY - GEN

T1 - Fabrication method to create high-aspect ratio pillars for photonic coupling of board level interconnects

AU - Debaes, C.

AU - Van Erps, J.

AU - Karppinen, Mikko

AU - Hiltunen, Jussi

AU - Suyal, H.

AU - Last, A.

AU - Lee, M. G.

AU - Karioja, Pentti

AU - Taghizadeh, M.

AU - Mohr, J.

AU - Thienpont, H.

AU - Glebov, A. L.

PY - 2008

Y1 - 2008

N2 - An important challenge that remains to date in board level optical interconnects is the coupling between the optical waveguides on printed wiring boards and the packaged optoelectronics chips, which are preferably surface mountable on the boards. One possible solution is the use of Ball Grid Array (BGA) packages. This approach offers a reliable attachment despite the large CTE mismatch between the organic FR4 board and the semiconductor materials. Collimation via micro-lenses is here typically deployed to couple the light vertically from the waveguide substrate to the optoelectronics while allowing for a small misalignment between board and package. In this work, we explore the fabrication issues of an alternative approach in which the vertical photonic connection between board and package is governed by a micro-optical pillar which is attached both to the board substrate and to the optoelectronic chips. Such an approach allows for high density connections and small, high-speed detector footprints while maintaining an acceptable tolerance between board and package. The pillar should exhibit some flexibility and thus a high-aspect ratio is preferred. This work presents and compares different fabrication methods and applies different materials for such high-aspect ratio pillars. The different fabrication methods are: photolithography, direct laser writing and deep proton writing. The selection of optical materials that was investigated is: SU8, Ormocers, PU and a multifunctional acrylate polymer. The resulting optical pillars have diameters ranging from 20um up to 80um, with total heights ranging between 30um and 100um (symbol for micron). The aspect-ratio of the fabricated structures ranges from 1.5 to 5.

AB - An important challenge that remains to date in board level optical interconnects is the coupling between the optical waveguides on printed wiring boards and the packaged optoelectronics chips, which are preferably surface mountable on the boards. One possible solution is the use of Ball Grid Array (BGA) packages. This approach offers a reliable attachment despite the large CTE mismatch between the organic FR4 board and the semiconductor materials. Collimation via micro-lenses is here typically deployed to couple the light vertically from the waveguide substrate to the optoelectronics while allowing for a small misalignment between board and package. In this work, we explore the fabrication issues of an alternative approach in which the vertical photonic connection between board and package is governed by a micro-optical pillar which is attached both to the board substrate and to the optoelectronic chips. Such an approach allows for high density connections and small, high-speed detector footprints while maintaining an acceptable tolerance between board and package. The pillar should exhibit some flexibility and thus a high-aspect ratio is preferred. This work presents and compares different fabrication methods and applies different materials for such high-aspect ratio pillars. The different fabrication methods are: photolithography, direct laser writing and deep proton writing. The selection of optical materials that was investigated is: SU8, Ormocers, PU and a multifunctional acrylate polymer. The resulting optical pillars have diameters ranging from 20um up to 80um, with total heights ranging between 30um and 100um (symbol for micron). The aspect-ratio of the fabricated structures ranges from 1.5 to 5.

KW - Deep proton writing

KW - Direct laser writing

KW - Micro-fabrication

KW - Optical interconnects

KW - UV-lithography

U2 - 10.1117/12.782721

DO - 10.1117/12.782721

M3 - Conference article in proceedings

T3 - Proceedings of SPIE

BT - Micro-Optics 2008

ER -

Debaes C, Van Erps J, Karppinen M, Hiltunen J, Suyal H, Last A et al. Fabrication method to create high-aspect ratio pillars for photonic coupling of board level interconnects. In Micro-Optics 2008. 2008. (Proceedings of SPIE, Vol. 6992). https://doi.org/10.1117/12.782721