FAQs – Microresist

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FAQ

Are there exact data available for the high etch resistance of ma-P 1200 resists?

The resists of the ma-P 1200 series exhibit a good etch resistance. E.g. ma-P 1200 gives very good results in dry etching (as with CF₄ or high density SF₆/O₂ plasma). The etch rates of the resists strongly depend on the etching conditions. The etching equipment has an influence, the amount of open wafer surface to be etched, the etch gas composition and all other parameters such as pressure, temperature or voltage. ma-P 1200 resists show a good thermal stability. That enables the thermal stabilisation of the resists for the subsequent plasma etching. E.g. a hardbake is recommendable at 120°C in an oven (with a temperature ramp to minimize the pattern rounding). For that also a stronger prebake is necessary. In case of a 7.5 µm thick film of ma-P 1275 that would be a prebake at 110°C for 5 – 10 min on a hotplate. We cannot deliver any more detailed data. This is nearly impossible since etching conditions can differ very much from lab to lab.

How can I avoid bubbles in the resist film?

Several reasons for the formation of bubbles in the resist are possible. Big bubbles could arise if the resist was shaken too much, or if the resist has undergone a bigger temperature change. They should disappear when the resist can “relax” a while (i.e. when the bottle is kept under constant climatic conditions in the cleanroom for some time). This applies mainly for resists of a higher viscosity. Bubbles occurring during the prebake of thick resist films are caused by the solvent evaporation. It is important to maintain a certain relaxation time between spin-coating and prebake to avoid this. Only high viscosity resists show this tendency. Smaller bubbles in the exposed area could have several reasons. Adjusting the respective process condition prevents the bubble formation:

The resist film isn´t dry enough, i.e. it wasn´t sufficiently softbaked (= prebaked).
The exposure dose was much too high. This is connected with a distinctly decreased developing time compared to the one at standard processing conditions.
c) Too much primer was used (HMDS on Si and SiO₂).
d) The cleanroom conditions were out of the tolerances. Especially a too high humidity can cause bubble formation.

Is ma-P 1200 resistant to strong acids?

In general ma-P 1200 positive photoresists withstand strong acids very well. Tests have shown that 2.5 µm thick ma-P 1225 and 7.5 µm thick ma-P 1275, both processed under standard conditions, resist concentrated HCl at 45…50 °C for at least 10 minutes without any problems. No erosion of the resist film is observed.
Concentrated HF is challenging for all photoresists (cf. QUESTION 4).
Also strongly oxidising acids can cause some problems. The resist stability depends on the temperature and composition of the etchant in such cases.

Can I use ma-P 1200 resists as etch mask for HF glass etching?

HF etching is a very demanding. HF doesn´t attack the resist. But it can diffuse under the photoresist and lift it from below causing bad adhesion of the resist on the substrate. This is why a film thickness as high as possible should be chosen, and the resist should be hardened (stronger prebake + hardbake). Nevertheless it depends strongly on the HF concentration and the etch time to what extend the photoresist sustains the etching.
In the literature it is mentioned that ma-P 1200 is suitable for etching with buffered HF [*].

[*] A. Pozzato, S. Dal Zilio, G. Fois, D. Vendramin, G. Mistura, M. Belotti, Y. Chen, M. Natali, Microelectronic Eng. 83 (2006), 884-888, doi:10.1016/j.mee.2006.01.012

Can I use positive photoresists for lift-off processes?

For lift-off processes a bi-layer resist system can be applied. E.g. LOR (a not photosensitive polymer provided by MicroChem Corp. for various film thicknesses) can be used as bottom layer. In a second step a positive resist e.g. from the ma-P 1200 series is applied as top layer. During the aqueous-alkaline development of the exposed areas of the positive resist film also the LOR film underneath is dissolved. The undercut profile in the bottom layer is adjusted by varying the development time and the prebake conditions for the LOR layer.
For some applications you can do the lift-off with a single-layer resist which does not give an undercut profile. E.g. the use of ma-P 1200 resist without an additional bottom layer would be sufficient – preferably with a somewhat higher film thickness to give sidewalls that can be reached by the stripper. The quality of the edges of the deposited metal layer is slightly worse than in a bi-layer process in this case.

Is there a developer that doesn´t corrode Al and Al containing substrates, respectively?

We recommend to apply “Developer Concentrate” by DOW Electronic Materials for developing resists of the ma-P 1200 series on Al and Al containing substrates. You can purchase the developer from our company. The developer is based on metasilicate which practically doesn´t corrode Al.

Examples of ma-P 1200 applications in the literature:

[1] W. Schrott, M. Svoboda, Z. Slouka, D. Šnita, Metal electrodes in plastic microfluidic systems, Microelectronic Engineering, 86 (2009), 1340-1342;
doi: 10.1016/j.mee.2009.01.001
ma-P 1275 is used as mould for electroplating Au and Cu structures to be used in plastic microfluidic systems.

[2] P.W. Leech, G.K. Reeves, A.S. Holland, Reactive ion etching of TiN, TiAlN, CrN and TiCN Films in CF4/O2 and CHF3/O2 Plasmas, Mater. Res. Soc. Symp. Proc. 890 (2006), 0890-Y08-13.1-6;doi: 10.1557/PROC-0890-Y08-13
ma-P 1205 is used as etch mask for plasma etching in the manufacture of stamps for imprint lithography.

[3] G. Kaltsas, A. Petropoulos, K. Tsougeni, D. N. Pagonis, T. Speliotis, E. Gogolides, A. G. Nassiopoulou, A novel microfabrication technology on organic substrates – Application to a thermal flow sensor, Journal of Physics: Conference Series 92 (2007) 012046; doi:10.1088/1742-6596/92/1/012046
ma-P 1275 is used in a lift-off process with Pt deposition in the manufacture of a thermal flow sensor.

[4] J.-C. Galas, D. Bartolo, V. Studer, Active connectors for microfluidic drops on demand, New J. Phys. 11 (2009) 075027;
doi:10.1088/1367-2630/11/7/075027
After reflow ma-P 1275HV is used as mask for moulding PDMS in the fabrication of active microfluidic connectors.

Are there resists for other film thicknesses available?

In general we offer ready–to-use resists for the film thicknesses given in the spin curves. Thinner film thicknesses can be obtained by diluting the resists with the recommended thinner (solvent mixture).
We guarantee unchanged resist properties of the ready-to-use resists before the expiration date and by storage of the resists at the recommended conditions.

Can the resists be used for film preparation by spray coating?

In general the resists were designed for film preparation by spin coating. Film preparation by spray coating should also be possible, but up to now we are not able to give guidelines for this method.

For which applications do you recommend ma-N 400 or ma-N 1400?

Both resist series differ in their available film thickness regions, their sensitivity, in the thermal stability of the resist patterns and in the profile of the undercutted patterns. For pattern transfer processes via PVD (physical vapour deposition) and lift-off the ma-N 400 is recommended for pattern transfer by evaporation or by sputtering with low thermal impact. ma-N 1400 is recommend for sputtering processes at higher temperatures.

What is the difference between the single layer negative resist systems ma-N 400 or ma-N 1400 and a bilayer system, e.g. LOR and a positive tone photoresist, for a pattern transfer process via lift-off, and what is the possible resolution of both systems?

For the lithographic processing of the single layer resist systems ma-N 400 and ma-N 1400 less processing steps are necessary than for the bilayer system. The thermal stability of the ma-N 1400 is higher than that of the ma-N 400 series and of the bilayer system. In general, the resolution of both systems, the single layer and the bilayer system is comparable, but the resolution of the bilayer system can be slightly better.

For clean lift-off processing, the resist film thickness should be 1.5 to 2 times that of the metal layer to be deposited.

What is the difference between the material systems Epocore/ Epoclad and Ormocore/ Ormoclad for the manufacture of polymer based waveguides?

Both material systems are composed of different chemical components. For a detailed comparison of both material systems, of the lithographic processing and the properties of the manufactured waveguides see the attached pdf document.

Summary in PDF »

Which adhesion promoter is suitable for which substrate (silicon Si, silicondioxide SiO2, glass, copper Cu or gold Au) and resist material?

In any case the substrates have to be free of impurities and moisture. They should be baked at 200 °C and cooled down to room temperature immediately before coating. Alternatively, oxygen or ozone plasma cleaning is recommended.
For improving the resist film adhesion to semiconductor substrates, e.g. FR 4, or for applying multiple coating and patterning of resist films, e.g. with Epoclad/ Epocore/ Epoclad, a short oxygen plasma activation step is recommended.

How can strongly crosslinked ma-N 2400, ma-N 400 and ma-N 1400 resist films be removed?

The ready-to-use removers mr-Rem 660 (NMP based), mr-Rem 400/ 500 (NMP free), mr-Rem 700 (NMP and NEP free), ma-R 404/ S (strongly alkaline) and aceton are recommended for the remove of the resists. Using mr-Rem 660 or mr-Rem 400 the remove can be done ultrasonic-assisted and at higher temperatures between 40 and 60 °C.
For the residue-free remove of during the pattern transfer process strongly crosslinked ma-N 2400, ma-N 400 or ma-N 1400 films an oxygen plasma step is highly recommended.

Are there data available for the high etch resistance of the ma-N 2400, ma-N 400 and ma-N 1400 series?

In general the resists exhibit a good etch resistance.
The series gave good results in dry etching (e.g. with CF4 or high dry density SF6/ O2 plasma). The etch rates of the resists strongly depend on the etching conditions. The etching equipment has an influence, the amount of open wafer surface to be etched, the etch gas composition and all other parameters such as pressure, temperature or voltage.

If required, the etch resistance and thermal stability of the resist can be increased by applying a higher prebake temperature or a longer prebake time. The developing time will increase in this case. Hardbaking of the developed resist patterns is also recommended for an increase of the etch resistance and the thermals stability.

In general the etch selectivity can be assume for the most etch applications as 1 to 1.

We cannot deliver any more detailed data. This is nearly impossible since etching conditions can differ very much from lab to lab.

Is there a resist available which is suitable for pattern transfer via HF-etch?

HF etching is a bit demanding. HF doesn´t attack the resist. But it can diffuse through and under the photoresist and lift it from below causing bad adhesion of the resist on the substrate. This is why a film thickness as high as possible should be chosen, and the resist should be hardened (stronger prebake + hardbake). Nevertheless it depends strongly on the HF concentration and the etch time how acceptably the photoresist sustains the etching.

Is there a developer that doesn´t corrode Al and Al containing substrates, respectively?

We recommend to apply metasilicate based developers for processing of the ma-N series resists on Al and Al containing substrates. You can purchase the developers from our company. Metasilicate practically doesn´t corrode Al.

How can be avoided the electrostatic charging effect during e-beam lithography when resist layers are exposed on insulating substrates?

There are some recommendations to avoid or reduce the electrostatic charging during e-beam exposure on insulating substrates.
1: Deposition of a thin metal layer as top coat layer:
Coat a thin metal layer (e.g. Al or Cr, ~ 10 – 20 nm) on top of the resist layer. The thin metal layer has to be removed after exposure and prior development.
In the case when using ma-N 2400 resist, the developer is aqueous alkaline based and the thin Al layer (which is soluble in weak alkaline solutions) is dissolved or removed during development step.
Thin Cr layer can be removed using e.g. Chrome Etch 18 solution.
2: Coat of a thin conductive layer.

[Ji] J. Ji et al “High-Throughput Nanohole Array Based System to Monitor Multiple Binding Events in Real Time” Anal. Chem. 80 (2008) 2491-2498

[Mohamed_1] K. Mohamed et al “Surface charging suppression using PEDOT/PSS in the fabrication of three dimensional structures on a quartz substrate” Microelectronic Engineering Vol. 86 (2009) 535 – 538”

Is there any literature available about the use/ processing or application of the resists ma-N 400, ma-N 1400, ma-N 2400, mr-EBL 6000, Epocore/ Epoclad or mr-DWL?

ma-N 2400:
[Bilenberg] B. Bilenberg, M. Schøler, P. Shi, M. S. Schmidt, P. Bøggild, M. Fink, C. Schuster, F. Reuther, C. Gruetzner, A. Kristensen „Comparison of high resolution negative electron beam resists” J. Vac. Sci. Technol. B 24(4) (2006) 1776

[Blideran] M.M. Blideran, M. Häffner, B.-E. Schuster, C. Raisch, H. Weigand, M. Fleischer, H. Peisert, T. Chassé, D.P. Kern „Improving etch selectivity and stability of novolak based negative resists by fluorine plasma treatment” Microelectronic Engineering 86 (2009) 769–772

[Cardenas] J. Cardenas, C. B. Poitras, J. T. Robinson, K. Preston, L. Chen, M. Lipson “Low loss etchless silicon photonic waveguides” Optics Express Vol. 17, No 6 (2009) 4752

[Chen] S. C. Chen, Y. C. Lin, J. C. Wu, L. Horng, C. H. Cheng „Parameter optimization for an ICP deep silicon etching system” Microsyst Technol (2007) 13: 465–474

[Elsner_1] H. Elsner, H.-G. Meyer, A. Voigt, G. Gruetzner “Evaluation of the ma-N 2400 series DUV photoresists for the electron beam exposure“ Microelectron. Eng. 46 (1999), 389–392

[Elsner_2] H. Elsner, H.-G. Meyer “Nanometer and high aspect ratio patterning by electron beam lithography using simply DUV negative tone resists” Microelectronic Engineering Vol. 57-58 (2001), 291 – 296

[Gondarenko] A. Gondarenko, J. S. Levy, M. Lipson “High confinement micron-scale silicon nitride high Q ring resonator” Optics Express Vol. 17, No. 14 (2009) 11366

[Konijn] M. Konijn, M.M. Alkaisi , R.J. Blaikie “Nanoimprint lithography of sub-100 nm 3D structures” Microelectronic Engineering 78–79 (2005) 653–658

[Mohamed_2] K. Mohamed, M. M. Alkaisi, R. J. Blaikie “A Three-Dimensional Ultraviolet Curable Nanoimprint Lithography (3D UV-NIL)” American Institute of Physics (AIP) Conf. Proc. 1151, (2009) 114

[Verhagen] E. Verhagen, A. Polman, L. (Kobus) Kuipers “Nanofocusing in laterally tapered plasmonic waveguides” Optics Express Vol. 16, No. 1 (2008) 45

[Voigt_1] A. Voigt, H. Elsner, H.-G. Meyer, G. Gruetzner “Nanometer patterning using ma-N 2400 series DUV negative photoresist and electron beam lithography“ Proc. SPIE 3676 (1999) 485–491

[Yu] Q. Yu, S. Braswell, B. Christin, J. Xu, P. M. Wallace, H. Gong, D. Kaminsky “Surface-enhanced Raman scattering on gold quasi-3D nanostructure and 2D nanohole arrays” Nanotechnology 21 (2010) 355301 (9pp)

ma-N 400/ ma-N 1400:
[Voigt_2] A. Voigt, G. Gruetzner, E. Sauer, S. Helm, T. Harder, S. Fehlberg, J. Bendig „A series of AZ-compatible negative photoresists“ Proc. SPIE 2348 (1995) 413–420

[Voigt_3] A. Voigt, M. Heinrich, K. Hauck, R. Mientus, G. Gruetzner, M. Töpper, O. Ehrmann „A Single Layer Negative Tone Lift-Off Photo Resist for Patterning a Magnetron Sputtered Ti/Pt/Au Contact System and for Solder Bumps“ Microelectron. Eng. 78 – 79 (2005) 503 – 508

ma-N 1400:
[Goeppl] M. Goeppl, A. Fragner, M. Baur, R. Bianchetti, S. Filipp, J. M. Fink, P. J. Leek, G. Puebla, L. Steffen, A. Wallraff „Coplanar Waveguide Resonators for Circuit Quantum Electrodynamics” J. Appl. Phys. 104, 113904 (2008)

[Lysko] J. M. Lysko, B. Latecki, M. Nikodem „Gas micro-fow-metering with the in-channel Pt resistors” J. of Telecommunications & Information Technology (2005) 98

ma-N 400:
[Figi] H. Figi, M. Jazbinsek, C. Hunziker, M. Koechlin, P. Guenter „Electro-optic single-crystalline organic waveguides and nanowires grown from the melt” Optics Express Vol. 16, No. 15 (2008) 11310

[Guo] H.C. Guo, D. Nau, A. Radke, X.P. Zhang, J. Stodolka, X.L. Yang, S.G. Tikhodeev, N.A. Gippius, H. Giessen “Large-area metallic photonic crystal fabrication with interference lithography and dry etching” Appl. Phys. B 81 (2005) 271–275

Epocore/ Epoclad:
[Ceyssens] F. Ceyssens, M. Driesen, K. Wouters, R. Puers, K.U. Leuven „A low-cost and highly integrated fiber optical pressure sensor system” Sensors and Actuators A 145–146 (2008) 81–86

[DeDockera] H.W.J.A. De Doncker, T. Guan, M. Driesen, R. Puers “Biaxial and Uniaxial Epoxy Accelerometers” Procedia Chemistry 1 (2009) 572–575

[Driesen] M. Driesen, K. Wouters, R. Puers „Etch rate optimization in reactive ion etching of epoxy photoresists” Procedia Chemistry 1 (2009) 796–799

[Gijsenbergh] P. Gijsenbergh, K. Wouters, K. Vanstreels, R. Puers “Determining the physical properties of EpoClad negative photoresist for use in MEMS applications” J. Micromech. Microeng. 21 (2011) 074001 (6pp)

[Himmelhuber] R. Himmelhuber, M. Fink, K. Pfeiffer, U. Ostrzinski, A. Klukowska, G. Gruetzner, R. Houbertz, H. Wolter „Innovative materials tailored for advanced microoptic applications“ Proc- SPIE Vol. 6487 (2007)

[Wouters_1] K. Wouters, R. Puers “Determining the Young’s modulus and creep effects in three different photo definable epoxies for MEMS applications” Sensors and Actuators A 156 (2009) 196–200

[Wouters_2] K. Wouters, H. De Doncker, R. Puers „Dynamic thermal mechanical characterization of Epoclad negative photoresist for micro mechanical structures” Microelectronic Engineering 87 (2010) 1278–1280

mr-DWL:
[Cadarso] V. J. Cadarso, K. Pfeiffer, U Ostrzinski, J. B. Bureau, G. A. Racine, A. Voigt, G. Gruetzner, J. Brugger “Direct writing laser of high aspect ratio epoxy microstructures” J. Micromech. Microeng. 21 (2011) 017003 (6pp)

What is a Hybrid Polymer (ORMOCER®)?

Hybrid polymers exhibit both inorganic and organic units and thus combine superior properties in one material class, e.g. outstanding optical transparency and non-yellowing behavior, high thermal and chemical stability as well as excellent mechanical stability.

Hybrid polymers are derived from the ORMOCER^®s (Organically Modified Ceramics), which were initially developed by the Fraunhofer Institute of Silicate Research (FhG ISC), Germany. ORMOCER^® is a trademark of the Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. München.

Are there any processing guidelines for the Hybrid Polymer products available?

For each Hybrid Polymer processing guidelines are available, which come with the delivery of the product. Please contact the corresponding product manager if you need further processing details in advance or use our contact form.

What are the Tg (glass transition temperature) values for the Hybrid Polymers?

Hybrid Polymers form a three-dimensional polymer network during curing, so no glass transition occurs once the material is crosslinked. Hybrid Polymers are duromeric.

Can I get Hybrid Polymers with lower film thicknesses?

Apart from the standard Hybrid Polymer products (see product listings) micro resist technology GmbH provides diluted Hybrid Polymer solutions customized for lower film thicknesses as special designs on request. The minimum attainable film thickness for the Hybrid Polymers is around 100 nm.

Does micro resist technology provide thinners for the Hybrid Polymer products?

In case you want to dilute a Hybrid Polymer by yourself in order to obtain thinner films after spin-coating, we provide the following solvent systems.

OrmoThin – Dilution for d > 0.5 μm (product-specific) *
ma-T 1050 – Dilution for d < 0.5 μm (product-specific) *

* More detailed information about the dilution of Hybrid Polymers can be found in the processing guidelines.

Is it possible to increase the adhesion of the Hybrid Polymers on substrates like glass, fused silica, or Si?

For glass, SiO₂, or metal surfaces it is advisable to use an adhesion promoter such as OrmoPrime^®08. For processing information please see the OrmoPrime^®08 processing guidelines.

Do I have to apply a release agent on mould, template or mask?

We strongly recommend to apply a release agent on the mould or stamp in order to generate a high adhesion contrast between mould or stamp and substrate. It is advisable to pre-treat the lithography mask, even if only a proximity lithography process is performed. The formed anti-sticking layer (ASL) prevents defects caused by sticking of the Hybrid Polymers on the mould/stamp. The most common release agent for silicon or silicon dioxide is “F13-TCS” (1H,1H,2H,2H-perfluorooctyl-trichlorosilane, CAS number [78560-45-9], available from common specialty chemicals suppliers).

The processing of F13-TCS for Si and SiO₂ moulds is described in: S. Park, “Anti-adhesive layers on nickel stamps for nanoimprint lithography“, Microel. Eng. 73-74 (2004), 196-201; H. Schift et al., „Controlled co-evaporation of silanes for nanoimprint stamps“, Nanotechnology 16 (2005), 171-175.

Can Hybrid Polymers also be cured thermally? Why are heating steps recommended?

Hybrid Polymers are only curable by UV exposure. The recommended heating steps fulfill other purposes:

The prebake step is recommended in order to remove possible air inclusions and to improve the uniformity of the hybrid polymer layer after the coating process. The prebake is mandatory when the Hybrid polymer is diluted by a solvent. Please note: Hybrid polymers do not harden during the prebake step and are still viscous thereafter!
The recommended post-exposure bake as well as the subsequent hardbake-step is recommended in order to increase the thermal and environmental stability and for improving the adhesion to the substrate.

Removal of cured Hybrid Polymers?

As Hybrid Polymers form a three-dimensional polymer network during curing, drastic conditions for removal are necessary, e.g. peel off via hot piranha etch. Alternatively O₂/ CHF₃ plasma can be used to remove the cured hybrid polymer. Do not use pure oxygen plasma! Porous SiO₂ will be formed.

What is the so-called „inhibition layer“? Which Hybrid Polymers form such an inhibition layer?

OrmoClear®, OrmoCore and OrmoClad as well as many acrylic-based polymers form a so-called inhibition layer when exposed under ambient atmosphere. This is due to partial quenching of radical polymerization by oxygen which results in a 5–15 μm thick layer of uncured material on the surface (“inhibition layer”). It has to be washed away in a development step (e.g. with OrmoDev). However, OrmoComp®, OrmoClear®FX and OrmoStamp® are not sensitive to oxygen and do not form an inhibition layer.

When applying UV moulding or (nano)imprint with hard molds (e.g. Si-, SiO2-, Ni-molds) there is no formation of an inhibition layer. However, using PDMS-molds (acting as some kind of “oxygen sponge”) will result in the formation of an inhibition layer.

Can I get nanoimprint polymer solutions for other film thicknesses?

Apart from the standard nanoimprint polymer and resist solutions (see product listings) micro resist technology GmbH provides solutions customised for other film thicknesses as special designs on request. The maximum attainable film thicknesses for each series are the following.

Nanoimprint polymer	Maximum attainable film thickness at 3000 rpm
mr-I 7000R	2 µm
mr-I 8000R	2 µm
SIPOL	4 µm
mr-I T85	25 µm
mr-I PMMA 35k	3 µm
mr-I 9000M	3 µm
mr-NIL 6000E	3 µm
mr-NIL210	2 µm
mr-UVCur21-Serie	1 µm
mr-UVCur21SF	1.6 µm (same as standard)
mr-XNIL26
mr-XNIL26SF	4.7 µm

Does micro resist technology provide solvent thinners for the nanoimprint products?

In the case that you want to dilute a nanoimprint polymer solution for yourself in order to get thinner films after spin-coating, we could provide the following solvent systems.

Nanoimprint polymer	Thinner
mr-I 7000R	ma-T 1050
mr-I 8000R	ma-T 1050
SIPOL	ma-T 1050
mr-I T85	No thinner available
mr-I PMMA 35k	ma-T 1045
mr-I 9000M	ma-T 1045
mr-NIL 6000E	ma-T 1045
mr-NIL210	ma-T 1078
mr-UVCur21-Serie	ma-T 1070
mr-UVCur21SF	–
mr-XNIL26	ma-T 1050
mr-XNIL26SF	ma-T 1050

Please keep in mind that you have to filter the diluted solutions again in order to avoid particle contamination and to guarantee a high film quality. Syringe filters work for that purpose.

Do you have processing guidelines for each product series?

You will get the processing guidelines with the delivery of the product. Please contact the corresponding product manager, if you need further processing details before.

Do I have to apply a release agent on my imprint mould?

We strongly recommend to apply a release agent on the imprint mould in order to generate a high adhesion contrast between mould and substrate. The formed anti-sticking layer (ASL) prevents defects caused by sticking of the nanoimprint polymer on the mould. The most common release agent for silicon or silicon dioxide stamps is “F13-TCS” (1H,1H,2H,2H-perfluorooctyl-trichlorosilan, CAS number [78560-45-9],available from common specialty chemicals suppliers).

The processing of F13-TCS for Si- and SiO₂ moulds is described in: M. Beck et al., Improving Stamps for 10 nm Level Wafer Scale Nanoimprint Lithography, Microel. Eng. 61-62 (2002), 441-448; H. Schift et al., Controlled co-evaporation of silanes for nanoimprint stamps, Nanotechnology 16 (2005), S171-S175.
Methods to deposit release agents on Nickel are described in S. Park, Anti-adhesive layers on nickel stamps for nanoimprint lithography, Microel. Eng. 73-74 (2004), 196-201; M. Keil, Process development and characterization of antisticking layers on nickel-based stamps designed for nanoimprint lithography, J. Vac. Sci. Technol. B22 (2004), 3283-3287.

What is the difference between the products mr NIL 6000E, mr-UVCur21, and mr-NIL210?

mr-NIL210 and mr-UVCur21 are UV-curable and liquid polymer systems for UV-based nanoimprint lithography. The spin-coated liquid films are cured by UV exposure at room temperature. There is no need for baking after the imprint step.

mr-NIL 6000E is a curing resist for thermal nanoimprint lithography, which forms a solid film after spin coating and prebake. It exhibits a low glass transition temperature (T_g) of about 40 °C. Thus, it can be imprinted at temperatures as low as 80 – 100 °C. But this epoxy-based material has to be cured by UV exposure and baking (comparable to the post exposure bake of chemically amplified resists). Otherwise there would be a reflow of the imprinted patterns on subsequent annealing. Curing can beneficially be done during imprinting in the imprint tool (if the machine has an exposure unit).

Do I have to use adhesion promoters on my substrates?

The use of adhesion promoters depends on the product series you want to use.

mr-I 7000E, mr-I 8000E, mr-I 7000R, mr-I 8000R: No adhesion promoter necessary on silicon, SiO₂, aluminium, or chromium surfaces.
mr-I T85: No adhesion promoter necessary on silicon or SiO₂ surfaces.
mr-I PMMA 35k: No adhesion promoter necessary on silicon, SiO₂ or aluminium surfaces.
mr-I 9000M: No adhesion promoter necessary on silicon or SiO₂ surfaces.
mr-NIL 6000E: No adhesion promoter necessary on silicon or SiO₂ surfaces.
mr-NIL210, mr-UVCur21, and mr-XNIL26: For improving the polymer film adhesion to Si or SiO₂ substrates it is advisable to apply an adhesion promoter on the substrate. We recommend the micro resist technologyproduct mr-APS1.Omnicoat (Microchem Corp., USA) works as an adhesion promoter, too. HMDS (Hexamethyl-disilazan) is not suitable.

+49 30 641 670 100

info@microresist.de

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