Taguchi optimization for the processing of Epon SU-8 resist

Eyre, Beverley; Blosiu, Julian O.; Wiberg, Dean

doi:10.1109/memsys.1998.659757

Cited by 25 publications

(25 citation statements)

References 4 publications

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“…Eyre et al have shown that, if the optical absorption of a photoresist is too high, UV light will not penetrate a thick resist layer and therefore clean, sharp images cannot be generated. 28 The absorption coefficient of fully formulated Avatrel 8000P (i.e., with epoxy-functionalized crosslinker, and photopackage) was measured after soft-bake, exposure, and post-exposure bake. As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Aqueous-Develop, Photosensitive Polynorbornene Dielectric: Properties and Characterization

Rajarathinam

Lightsey

Osborn

et al. 2009

Journal of Elec Materi

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The properties of a new aqueous-base-develop, negative-tone photosensitive polynorbornene have been characterized. High-aspect-ratio features of 7:1 (height:width) were produced in 70-lm-thick films in a single coat with straight side-wall profiles and high fidelity. The polymer films studied had contrast of 12.2 and low absorption coefficient. To evaluate the polymerÕs suitability to microelectronics applications, epoxy crosslinking reactions were studied as a function of processing condition through Fourier-transform infrared spectroscopy, nanoindentation, and dielectric measurements. The fully crosslinked films had an elastic modulus of 2.9 GPa and hardness of 0.18 GPa.

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Section: Resultsmentioning

confidence: 99%

Aqueous-Develop, Photosensitive Polynorbornene Dielectric: Properties and Characterization

Rajarathinam

Lightsey

Osborn

et al. 2009

Journal of Elec Materi

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“…Based on this analysis, an L9 orthogonal array was used to reduce the number of experiments at each thickness to 9. A detailed description of Taguchi analysis can be found in other references [5,13,19]. Table 2 gives the experimental conditions of each of the processing parameters.…”

Section: Experimental Methodologymentioning

confidence: 99%

“…Overall, the results of these studies [10,15] highlight the importance that physical, chemical and mechanical processes play in SU-8 lithography, but they also show the necessity of the parametric optimisation of the process. The optimisation of SU-8 processing conditions with respect to aspect-ratio, resolution and adhesion has been carried out by two different groups using the Taguchi method [5,19]. Eyre et al reported an optimised process for three thicknesses (50, 100 and 220 lm) while demonstrating the use of the Taguchi method for SU-8 optimisation.…”

Section: Introductionmentioning

confidence: 99%

Optimisation of SU-8 processing parameters for deep X-ray lithography

et al. 2005

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The negative photoresist SU-8 has been recognised as an unique resist, equally useful for conventional UV lithography as well as deep X-ray lithography (DXRL) applications [2,7,12,17,18]. One of the major limitations in the use of SU-8 in lithographic processes is the occurrence of internal stress [15]. The processing parameters investigated for DXRL of SU-8 included resist thickness (450-850 lm), soft bake time (7-11 h), exposure dose (30-70 J/cm 3 ), post exposure bake time (20, 40, 60 min) and development time. The effect of these parameters on stress was evaluated using wafer curvature measurements. Taguchi optimisation techniques have been used to asses the contribution of these parameters on the stress of the developed structures. This study shows that softbake time contributes the most to stress in the SU-8 film at 50%, followed by the exposure dose and post exposure bake with 30% and 15% respectively. Stress varied somewhat linearly with thickness. At higher thickness, the deposition process needs to be changed for very high aspect ratio structures. The main objective of this work has been to optimise the processing conditions of thick SU-8 films for DXRL.

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“…Edge bead is another difficulty commonly encountered in contact UV lithography using ultra-thick photoresist (Eyre et al 1998;Lin et al 2002). It refers to the thicker photoresist around the rim of the wafer and is due to the radial force pattern inherent to spin coating.…”

Section: Introductionmentioning

confidence: 99%

Reduction of diffraction effect for fabrication of very high aspect ratio microchannels in SU-8 over large area by soft cushion technology

et al. 2005

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Edge bead due to spin coating has been found to cause an air gap as large as 53 lm for a 99-lm thick (measured at the wafer center) SU-8 coating over a 4-in. wafer. This caused poor mask width replication and non-uniformity of SU-8 pattern width. We have devised a process using a soft cushion technology to improve mask dimension replication and large-area pattern uniformity. A soft cushion was placed beneath the substrate to produce convex bending of the wafer in order to improve the contact between the mask and photoresist top surface during UV exposure. Dramatic improvements in pattern uniformity, from over 30% variation in SU-8 width across the wafer to less than 10%, and mask width replication, from 54% deviation from mask width to 20%, have been demonstrated. Numerically calculated increases in SU-8 width from the wafer center to the edge bead using the Fresnel diffraction equation match well with observed values. Further, employment of this technique with a narrow (10 lm) dark-field mask enabled the fabrication over the entire surface of 4-in. diameter wafers of dense SU-8 gratings separated by microchannels with aspect ratio over 18.

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Taguchi optimization for the processing of Epon SU-8 resist

Cited by 25 publications

References 4 publications

Aqueous-Develop, Photosensitive Polynorbornene Dielectric: Properties and Characterization

Aqueous-Develop, Photosensitive Polynorbornene Dielectric: Properties and Characterization

Optimisation of SU-8 processing parameters for deep X-ray lithography

Reduction of diffraction effect for fabrication of very high aspect ratio microchannels in SU-8 over large area by soft cushion technology

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