Photoresist patterned thick-film piezoelectric elements on silicon

Frood, A.J.M.; Beeby, Steve; Tudor, John; White, NM

doi:10.1007/s10832-007-9049-y

Cited by 6 publications

(6 citation statements)

References 7 publications

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“…While producing well-formed high aspect ratio features up to 100 μm in height [13], BPR100 is not easy to dispense due to its viscosity. It is thus difficult to prevent bubbles from entering and making the photoresist nonuniform [14]. Also, development has to be done at raised temperatures and stripping requires mechanical agitation.…”

Section: Introductionmentioning

confidence: 99%

Thick single-layer positive photoresist mold and poly(dimethylsiloxane) (PDMS) dry etching for the fabrication of a glass–PDMS–glass microfluidic device

2008

J. Micromech. Microeng.

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Poly(dimethylsiloxane) (PDMS) is an elastomer widely used in microfluidic devices due to desirable characteristics such as its low cost and moldability. Photoresist patterned to form microfluidic features is often used as a mold, and SU-8 is commonly used. However, negative photoresists like SU-8 are difficult to remove, as compared to positive photoresists. Here, a method of forming microfluidic structures in the PDMS with an AZ9260 thick positive (Novolak-based) photoresist using standard microfabrication technique is reported. The chip consisted of a sandwich structure with glass on the top and bottom and PDMS with microfluidic channels in the middle; these structures have PDMS sidewalls, but are free of PDMS on the bottom and top. A single layer of the positive AZ9260 photoresist was spun to controllable and uniform thicknesses of up to 49 μm and used as a sacrificial mold to create PDMS microfluidic features. Reactive ion etching (RIE) with CF 4 and O 2 gases and a liftoff technique was used to create these features, and subsequent irreversible bonding to glass was achieved by activation in oxygen plasma by RIE. The final depths of channels were about 20-30 μm. The effect of the gas flow rate ratios on the bonding ability was investigated, and the surfaces of etched PDMS were studied under a scanning electron microscope (SEM), and the bonding strength was measured to be 0.85 MPa. The fabricated microfluidic device was tested and shown to be leak free.

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Section: Introductionmentioning

confidence: 99%

Thick single-layer positive photoresist mold and poly(dimethylsiloxane) (PDMS) dry etching for the fabrication of a glass–PDMS–glass microfluidic device

2008

J. Micromech. Microeng.

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“…Then, the parts were immersed in a 20% KOH solution at a temperature of 80°C. This resulted in the PZT films peeling off from the silicon substrates in ∼10 min causing a slight damage to the films 24. Finally the mass of the films was measured using a precision electronic balance (OHAUS Corp, Pine Brook, NJ) after clearing Pt/Ti/SiO 2 debris and drying.…”

Section: Resultsmentioning

confidence: 99%

“…This resulted in the PZT films peeling off from the silicon substrates in B10 min causing a slight damage to the films. 24 Finally the mass of the films was measured using a precision electronic balance (OHAUS Corp, Pine Brook, NJ) after clearing Pt/Ti/SiO 2 debris and drying. Earlier, Nelson detailed various sets of dielectric mixture equations considering the dielectric constant and density of different materials and can often be used to predict the density of films from its dielectric constant value or vice versa.…”

Section: Resultsmentioning

confidence: 99%

Dielectric and Piezoelectric Properties of PZT Composite Thick Films with Variable Solution to Powder Ratios

Zhou

Shung

et al. 2009

Journal of the American Ceramic Society

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The use of PZT films in sliver-mode high-frequency ultrasonic transducers applications requires thick, dense, and crack-free films with excellent piezoelectric and dielectric properties. In this work, PZT composite solutions were used to deposit PZT films >10 μm in thickness. It was found that the functional properties depend strongly on the mass ratio of PZT sol-gel solution to PZT powder in the composite solution. Both the remanent polarization, P r , and transverse piezoelectric coefficient, e 31,f , increase with increasing proportion of the sol-gel solution in the precursor. Films prepared using a solution-to-powder mass ratio of 0.5 have a remanent polarization of 8 μC/cm 2 , a dielectric constant of 450 (at 1 kHz), and e 31,f = −2.8 C/m 2 . Increasing the solution-to-powder mass ratio to 6, the films were found to have remanent polarizations as large as 37 μC/cm 2 , a dielectric constant of 1250 (at 1 kHz) and e 31,f = −5.8 C/m 2 .

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“…For achieving higher resist thicknesses, multiple coatings using the positive AZ photoresist providing thicknesses of up to 100 lm were investigated by Frood et al (2007). Several photoresists have been developed for high thicknesses up to 100 lm in single spin coating step such as AR-N 4400 (CAR 44) from ALLRESIST (2007), Epoclad from Micro resist technology (2007), and KMPR 1000 (Ito et al 2005).…”

Section: Technology Development For High Aspect Ratio Micromoldsmentioning

confidence: 99%

High aspect ratio micromolds for the electroplating of micro electro discharge machining tools

Traisigkhachol

Gatzen

2010

Microsyst Technol

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A new approach using micro systems technology for the fabrication of micro electro discharge machining tool electrodes using a combination of positive and negative photoresist fabricated with near UV-lithography as high aspect ratio micromolds was developed. Micromolds with heights varying from 200 to 650 lm and an aspect ratio of up to 26:1 were fabricated using SU-8 TM , a negative photoresist, as a micromold for the electrodeposition of the micro tool electrodes. Besides serving as a micromold, SU-8 TM is also used as an insulator to protect the sidewalls of the tool electrodes from corrosions. The fabrication of the SU-8 TM micromold was optimized to avoid cracks and delaminations. In the experiments, electrodes made of Cu, WCu, and CoFe were deposited into these High Aspect Ratio Micro Structure Technology (HARMST) micromolds. Furthermore, the process technique for electroplating in deep micromolds is discussed in this paper.

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Photoresist patterned thick-film piezoelectric elements on silicon

Cited by 6 publications

References 7 publications

Thick single-layer positive photoresist mold and poly(dimethylsiloxane) (PDMS) dry etching for the fabrication of a glass–PDMS–glass microfluidic device

Thick single-layer positive photoresist mold and poly(dimethylsiloxane) (PDMS) dry etching for the fabrication of a glass–PDMS–glass microfluidic device

Dielectric and Piezoelectric Properties of PZT Composite Thick Films with Variable Solution to Powder Ratios

High aspect ratio micromolds for the electroplating of micro electro discharge machining tools

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