Ultrasonic supported development of irradiated micro-structures

El-Kholi, A.; Mohr, Jürgen; Stransky, Roman

doi:10.1016/0167-9317(94)90141-4

Cited by 17 publications

(7 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Even though the deposited dose for larger resist structures is above the developing limit, these structures adhere to the substrate because diffusion effects limit the developing process (El-Kholi et al, 1994). In this case the diffusion time of the developer into the approx.…”

Section: Secondary Radiation From the Substratementioning

confidence: 99%

Characterisation of defects in very high deep-etch X-ray lithography microstructures

Pantenburg¹,

Achenbach²,

Mohr³

1998

Microsystem Technologies

Self Cite

View full text Add to dashboard Cite

In deep X-ray lithography synchrotron radiation is applied to pattern several hundred micrometer thick resist layers. This technique has been used to obtain micro structures with an aspect ratio up to 100 and dimensions in the micrometer range. The structures are characterised by straight walls and a typical sidewall roughness of approximately 50 nm.To be able to fabricate n-coherent structures with any lateral shape and to have the possibility to use these resist microstructures in an additional electroforming process the resist is usually mounted on a ceramic or metallic substrate. Due to the different thermal expansion coefficients of the resist material and the substrate a developing temperature of 37°C produces cracks in the resist structures depending on the microstructure design. These defects are not observed if the developing temperature is reduced to 20°C. Better structure quality is obtained using the GG-developer instead of MIBK/IPA, but the developing rate is decreased. Measurements of the developing rate of PMMA in GG-developer at different temperatures show that the contrast of the developer-resist system is increased at 20°C compared to 37°C.

show abstract

Section: Secondary Radiation From the Substratementioning

confidence: 99%

Characterisation of defects in very high deep-etch X-ray lithography microstructures

Pantenburg¹,

Achenbach²,

Mohr³

1998

Microsystem Technologies

Self Cite

View full text Add to dashboard Cite

show abstract

“…The etching rate became slightly larger as increasing the beam (pattern) size if the substrate temperature was kept the same. We did not find any reduction in the etching rate, namely transportation effect (El-kholi et al (1994) ), for large aspect ratios (much more than 1). With the minimum pattern feature on the order of a few microns, quality of the microstructures which we achieved by this process was very close to that made by the LIGA process (Zhang and Katoh (1996)).…”

Section: Resultsmentioning

confidence: 73%

High aspect ratio micromachining by synchrotron radiation direct photo-etching

Katoh

Zhang

1998

Microsystem Technologies

View full text Add to dashboard Cite

We have carried out micromachining of Teflonpolymers such as PTFE, PFA and FEP as well as optical crystal such as NaCl and LiF by synchrotron radiation direct (without any chemicals) photo-etching and succeeded in creating microstructures with very high aspect ratios. The maximum aspect-ratio achieved was 50 and the maximum processing depth was 1500 microns. Dependence of the etching rate on the synchrotron beam current and on the substrate temperature was studied. Based on the study, we could use only x-rays from the synchrotron radiation so as to apply x-ray lithography technology (such as using an x-ray mask and processing in He atmosphere) to our process. A rise in the sample temperature results in significant enhancement of the etching rate. The etching rate measured was on the order of a few 100 m/min. So that this process is much faster than hard x-ray deep lithography for the processing of more than 100 m deep microstructures.

show abstract

“…The developing process of microstructures was subject not only to the problem of solubility but also of transportation. The developing process of different geometric microstructures can be improved through the application of ultrasound [19]. Developing behaviour can be divided into three consecutive reactions, such as (1) the developer diffuses to the surface of the photoresist; (2) the photoresist and developer take part in chemical reactions; and (3) the reaction products diffuse into the developer [20].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of a micro-punching head using LIGA and stacking processes

Pan¹,

Wu²,

Tsai³

et al. 2008

J. Micromech. Microeng.

View full text Add to dashboard Cite

A simple stacking process to fabricate microstructures with a high aspect ratio of 30 is presented in this study. For the x-ray absorption of a substance, an analytical model of the absorption dosage (exposure dosage) along a depth of x is developed. It can accurately estimate the time and dosage required for exposure. Based on the calculated result, 1 mm thick PMMA (polymethylmethacrylate) photoresist with a separate gold (Au)/graphite mask is exposed using x-rays followed by a developing process. Then a stacking process is applied for these 1 mm thick PMMA microstructures to form a microstructure with a high aspect ratio. With this stacking method, a PMMA microstructure with a height of 3 mm has been fabricated. In addition, a nickel–cobalt (Ni–Co) alloy electroplating process is applied to fabricate a metallic mold with high hardness. The hardness of the mold by electroforming is the key factor to the quality of the micro-punch process. As an integrated micro-punch head for IC leadframes, the hardness should be higher than 500 Vickers hardness (Hv). In addition, it was found experimentally that changing the ratio of Ni sulfamate to Co sulfamate can affect the deposit hardness and internal stress. The deposit internal stress varies with Co content. Thus, it is necessary to add a stress reducer to improve the hardness and reduce internal stress. A hardness of the mold of 550–560 Hv with 26–28 wt.% of Co and zero internal stress have been made successfully after adding a stress reducer. With this electroplating technique, a micro-punching head with high hardness and high aspect ratio can be fabricated by LIGA technology.

show abstract

Ultrasonic supported development of irradiated micro-structures

Cited by 17 publications

References 2 publications

Characterisation of defects in very high deep-etch X-ray lithography microstructures

Characterisation of defects in very high deep-etch X-ray lithography microstructures

High aspect ratio micromachining by synchrotron radiation direct photo-etching

Fabrication of a micro-punching head using LIGA and stacking processes

Contact Info

Product

Resources

About