Planarization and fabrication of bridges across deep grooves or holes in silicon using a dry film photoresist followed by an etch back

Spiering, V.L.; Berenschot, J.W.; Elwenspoek, Michael Curt

doi:10.1088/0960-1317/5/2/036

Cited by 7 publications

(7 citation statements)

References 4 publications

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“…Due to the corrugated zones, standard techniques like lithography and lift-off cannot be applied. Methods are known that provide planarization after realization of corrugated zones, 16,17 however the application of these methods is not very general and non-trivial.…”

Section: Design Of a Microreactor With Heaters In Silicon Nitride Tub...mentioning

confidence: 99%

Fabrication and characterization of high-temperature microreactors with thin film heater and sensor patterns in silicon nitride tubes

et al. 2005

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In this paper the fabrication and electrical characterization of a silicon microreactor for high-temperature catalytic gas phase reactions, like Rh-catalyzed catalytic partial oxidation of methane into synthesis gas, is presented. The microreactor, realized with micromachining technologies, contains silicon nitride tubes that are suspended in a flow channel. These tubes contain metal thin films that heat the gas mixture in the channel and sense its temperature. The metal patterns are defined by using the channel geometry as a shadow mask. Furthermore, a new method to obtain Pt thin films with good adhesive properties, also at elevated temperatures, without adhesion metal is implemented in the fabrication process. Based on different experiments, it is concluded that the electrical behaviour at high temperatures of Pt thin films without adhesion layer is better than that of Pt/Ta films. Furthermore, it is found that the temperature coefficient of resistance (TCR) and the resistivity of the thin films are stable for up to tens of hours when the temperature-range during operation of the microreactor is below the so-called "burn-in" temperature. Experiments showed that the presented suspended-tube microreactors with heaters and temperature sensors of Pt thin films can be operated safely and in a stable way at temperatures up to 700 degrees C for over 20 h. This type of microreactor solves the electrical breakdown problem that was previously reported by us in flat-membrane microreactors that were operated at temperatures above 600 degrees C.

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Section: Design Of a Microreactor With Heaters In Silicon Nitride Tub...mentioning

confidence: 99%

Fabrication and characterization of high-temperature microreactors with thin film heater and sensor patterns in silicon nitride tubes

et al. 2005

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“…(2) The photoresist bridge layer is self-assembled and transferred to the wafer surface. (3) After baked at 70°C for 20 min and 110°C for 90 s, the photoresist bridge layer is UV -exposed, developed, and post-baked to reveal anchor holes. (4) 50-nm-thick TiW and 350-nm-thick Cu layers are successively deposited over the bridge layer by magnetron sputtering at room temperature.…”

Section: Statnding Beamsmentioning

confidence: 99%

“…Laminated dry film resist demonstrates a unique ability to cross over pre etched through holes or trenches by paste coating [3][4][5], which emerges as a new alternative for the fabrication of free-standing structures over pre etched through holes and deep trenches. However, the thickness of the dry films is usually over 15 !lm, which decreases the planarity of the wafer surfaces when the films are used as bridge layers.…”

Section: Introductionmentioning

confidence: 99%

Self-assembly and transferring of photoresist as planar layer for fabrication of TSV and free standing beams

Yang

Dou

et al. 2011

2011 16th International Solid-State Sensors, Actuators and Microsystems Conference

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This paper outlines a novel technique for using suspended photoresist above holes and trenches as planar bridge layer in the fabrication of through silicon vias ( T SVs) and beams. Photoresist film is formed through self-assembly on water surface and then transferred to a wafer as planar bridge layer to cover previously fabricated holes and trenches, which can be patterned with photolithography. The suspension capability of the photoresist bridge layer increases with the film thickness. 300 to 500 nm thick photoresist films are able to be suspended on through-vias of up to 60 �m in diameter and 50 �m wide trenches. A novel process flow of TSV has been developed. TSVs of up to 60 �m in diameter have been fabricated, and the upper side of the TSVs is automatically planarized. Cu beams suspended above deep trenches have also been fabricated with the technique. KEYWORDS

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“…The design of MEMS devices is often limited by the impossibility of layer patterning by liquid-phase photoresist spin coating on a wafer surface containing large steps in height. A dry film Ordyl AP838 (Elga Europe) was used to planarize the surface over an etched grove to provide a flat surface for further processing 4 .…”

Section: Introductionmentioning

confidence: 99%

Dry film process development for electroplating and lift-off of metal layers

Kanikella

O’Keefe

Kim

2008

Micromachining and Microfabrication Process Technology XIII

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A dry film photoresist (MX 5020 from DuPont Electronic Technologies) was selected to fabricate microstructures with high sidewall verticality. Sidewall verticality of dry film is very important for better pattern transfer and sharp features. A fractional factorial design (FFD) method was used to identify the significant process variables for sidewall optimization. The most significant factor was determined to be exposure energy, as other factors were not significant in improving sidewall verticality. It was found that the sidewall slope increased with a decrease in exposure energy. The fabricated dry film molds with nearly vertical sidewalls (86°) were used for copper electroplating and sputter deposited Ti lift-off applications. The electroplating process was also optimized using a fractional factorial design. A lower plating current density resulted in a smoother, fine grained deposit compared to the higher current density, and the dry film resist was able to withstand a very acidic (pH ~1) copper sulfate plating solution. Sputtered titanium films with a thickness of 200 nm were also successfully lifted-off using dry film patterning.

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Planarization and fabrication of bridges across deep grooves or holes in silicon using a dry film photoresist followed by an etch back

Cited by 7 publications

References 4 publications

Fabrication and characterization of high-temperature microreactors with thin film heater and sensor patterns in silicon nitride tubes

Fabrication and characterization of high-temperature microreactors with thin film heater and sensor patterns in silicon nitride tubes

Self-assembly and transferring of photoresist as planar layer for fabrication of TSV and free standing beams

Dry film process development for electroplating and lift-off of metal layers

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