Design and measurement of stress indicator structures for the characterization of Epoclad negative photoresist

Wouters, Kristof; Puers, Robert

doi:10.1088/0960-1317/19/7/074019

Cited by 10 publications

(9 citation statements)

References 13 publications

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“…For our sensor, the thermo-optic coefficient of the EpoCore is −71 ppm/K [13], but no manufacturer data about the coefficient of thermal expansion of EpoCore and EpoClad exist, and rare values from literature differ strongly. While Wouters and Puers approximated the CTE of EpoClad to be in the range of 80 ± 10 ppm/K [30], Shi calculated the CTE of EpoCore to be 20-30 ppm/K [31], but obtained this result from a sensor on a glass substrate. Nevertheless, we assume that the dominant thermal expansion is caused by the COP substrate with a CTE of 60 ppm/K, thus we would expect a temperature sensitivity of −11 ppm/K.…”

Section: Influence Of Temperaturementioning

confidence: 99%

Manufacturing and Characterization of Femtosecond Laser-Inscribed Bragg Grating in Polymer Waveguide Operation in an IR-A Wavelength Range

Meyer

Nedjalkov

Kelb

et al. 2020

Sensors

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Optical sensors, such as fiber Bragg gratings, offer advantages compared to other sensors in many technological fields due to their outstanding characteristics. This sensor technology is currently transferred to polymer waveguides that provide the potential for cost-effective, easy, and flexible manufacturing of planar structures. While sensor production itself, in the majority of cases, is performed by means of phase mask technique, which is limited in terms of its degrees of freedom, other inscription techniques enable the manufacture of more adaptable sensor elements for a wider range of applications. In this article, we demonstrate the point-by-point femtosecond laser direct inscription method for the processing of polymer Bragg gratings into waveguides of the epoxy-based negative photoresist material EpoCore for a wavelength range around 850 nm. By characterizing the obtained grating back-reflection of the produced sensing element, we determined the sensitivity for the state variables temperature, humidity, and strain to be 45 pm/K, 19 pm/%, and 0.26 pm/µε, respectively. Individual and more complex grating structures can be developed from this information, thus opening new fields of utilization.

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Section: Influence Of Temperaturementioning

confidence: 99%

Manufacturing and Characterization of Femtosecond Laser-Inscribed Bragg Grating in Polymer Waveguide Operation in an IR-A Wavelength Range

Meyer

Nedjalkov

Kelb

et al. 2020

Sensors

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“…In particular, this enables us to quantify the volume change of the epoxy due to the absorption or desorption of a liquid. The working principle is relatively simple, see figure 1 [17]. When the test beams are freestanding, they will relax their built-in stress and move the amplification beam.…”

Section: The Used Stress Indicator Structurementioning

confidence: 99%

Diffusing and swelling in SU-8: insight in material properties and processing

Wouters

Puers

2010

J. Micromech. Microeng.

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The swelling behavior of SU-8 is studied. It is well known that negative resist swells under the influence of common processing liquids, developers, solvents, etc. However, when SU-8 is used as a construction material for plating molds, or for permanent structures, for instance in microfluidics or as active mechanical components in the MEM structure, a more quantitative investigation is needed. In this paper, the volume change is measured when the SU-8 epoxy is submersed in common processing liquids. An analytical model is derived to link the diffusion mechanism to the mechanical response of the SU-8 material. Using the obtained model, the diffusion constants are calculated from the mechanical displacement measurements. Also, the derived model can be used for the prediction of the mechanical behavior of SU-8 structures in the future. The swelling behavior is also correlated with the internal stresses that exist in the SU-8 film. This helps to understand crack formation and delamination of SU-8 patterns during processing. The results show that the built-in stress in the SU-8 epoxy is strongly dependent on the ambient or submersion liquid and that this effect in itself is strongly dependent on the softbake procedure of the polymer. The built-in stress in SU-8 was found to be maximum when submersed in propylene glycol methyl ether acetate and in isopropyl alcohol, both liquids that are used during the development, and found to be very low in water.

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“…7. For the rest of this work, we have selected these materials for several additional reasons as well: • Improved thermal stability as the oxides have a much lower thermal expansion coefficient (0.55 ppm/K for silicon oxide vs 87±10 ppm/K for EpoClad [43]).…”

Section: Silicon Oxide-silicon Oxynitride Planar Waveguidesmentioning

confidence: 99%

Lippmann waveguide spectrometer with enhanced throughput and bandwidth for space and commercial applications

Madi¹,

Ceyssens²,

Shorubalko³

et al. 2018

Opt. Express

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This article presents an innovative high spectral resolution waveguide spectrometer, from the concept to the prototype demonstration and the test results. The main goal is to build the smallest possible Fourier transform spectrometer (FTS) with state of the art technology. This waveguide FTS takes advantage of a customized pattern of nano-samplers fabricated on the surface of a planar waveguide that allows the increase of the measurement points necessary for increasing the spectral bandwidth of the FTS in a fully static way. The use of a planar waveguide on the other hand allows enhancing the throughput in a waveguide spectrometer compared to the conventional devices made of single-mode waveguides. A prototype is made in silicon oxynitride/silicon dioxide technology and characterized in the visible range. This waveguide spectrometer shows a nominal bandwidth of 256~nm at a central wavelength of 633~nm thanks to a custom pattern of nanodisks providing a μm sampling interval. The implementation of this innovative waveguide FTS for a real-case scenario is explored and further development of such device for the imaging FTS application is discussed.

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Design and measurement of stress indicator structures for the characterization of Epoclad negative photoresist

Cited by 10 publications

References 13 publications

Manufacturing and Characterization of Femtosecond Laser-Inscribed Bragg Grating in Polymer Waveguide Operation in an IR-A Wavelength Range

Manufacturing and Characterization of Femtosecond Laser-Inscribed Bragg Grating in Polymer Waveguide Operation in an IR-A Wavelength Range

Diffusing and swelling in SU-8: insight in material properties and processing

Lippmann waveguide spectrometer with enhanced throughput and bandwidth for space and commercial applications

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