Fabrication of Microchannels Using Polynorbornene Photosensitive Sacrificial Materials

Wu, Xiaoqun; Reed, H.A.; Wang, Yong; Rhodes, Larry F.; Elce, Ed; Ravikiran, R.; Shick, Robert A.; Henderson, Clifford L.; Allen, Sue Ann Bidstrup; Kohl, Paul A.

doi:10.1149/1.1596955

Cited by 32 publications

(25 citation statements)

References 10 publications

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“…(1). where α is a dimensionless mass fraction, k is the rate constant, n is the reaction order, A is the Arrhenius pre‐exponential factor, E a is the activation energy, R is the universal gas constant, t is the time, and T is the temperature 16. Wu et al used a constant reaction rate versus mass fraction, which is reasonable for their specific polymer decomposition process 16. However, significant deviation from ideal fitting may occur in the carbonate cleavage process because the polymer contains a small amount of an impurity, which can consume the acid.…”

Section: Resultsmentioning

confidence: 99%

Photoacid generators for catalytic decomposition of polycarbonate

Cupta

Joseph

Kohl

2007

J of Applied Polymer Sci

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The photo-activated, acid catalyzed decomposition of polycarbonate was investigated in this study. The impact of the chemical and physical properties of the photoacid generators (PAG) and the ambient atmosphere effect on polycarbonate decomposition were discussed. The photo-patterns resulted from the photoacid catalyzed decomposition of a polycarbonate can be used as a sacrificial placeholder for fabrication of microelectromechanical and microfluidic devices. The effects of acid strength, vapor pressure of the acid, PAG activation process, and ambient conditions (temperature, moisture, and oxygen concentrations) on polymer film decomposition were studied. Several superacids (e.g. triflic and nonaflic based PAGs) were not suitable for decomposition of the polycarbonate because of their high vapor pressures resulting in the high volatility properties. From the decomposition experiments it was found that the nonfluorinated sulfonic acid based PAGs do not posses the superacidity needed for decomposition. Perfluorinated methide and a tetrakis (pentafluoropheyl)borate PAG were effective in the decomposition of polycarbonate films. The combination of two PAGs, one which generates high vapor pressure acid (thus, highly volatile) and the other with a lower vapor pressure acid (thus, less volatile) showed very low residue levels. This is because of the volatility of the generated high vapor pressure acid (usually remaining acid in the film was the cause of the residue left behind) and the remaining nonvolatile low vapor pressure acid was sufficient to decompose the polycarbonate that was not decomposed by the generated high volatile acid.

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Section: Resultsmentioning

confidence: 99%

Photoacid generators for catalytic decomposition of polycarbonate

Cupta

Joseph

Kohl

2007

J of Applied Polymer Sci

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“…The furnace ramp rate was adjusted so that the polymer decomposition rate was 0.5 wt.%/min to avoid excess pressure build-up during decomposition. 16,17 3 8 temperature profile during the thermal decomposition step. The half-pitch of the Cu/air-gap interconnect was 200 nm, and the height of the Cu metal lines was 380 nm.…”

Section: Methodsmentioning

confidence: 99%

Air-Gaps for High-Performance On-Chip Interconnect Part II: Modeling, Fabrication, and Characterization

Park

Allen

Kohl

2008

Journal of Elec Materi

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Air-gaps are the ultimate low-k material in microelectronics due to air having a low dielectric constant close to 1.0. The interconnect capacitance can further be reduced by extending the air-gaps into the interlayer dielectric region to reduce the fringing electric field. An electrostatic model (200 nm half-pitch interconnect with an aspect ratio of 2.0), was used to evaluate the dielectric properties of the air-gap structures. The incorporation of air-gaps into the intrametal dielectric region reduced the capacitance by 39% compared with SiO 2 . Extending the air-gap 100 nm into the top and bottom interlayer SiO 2 region lowered the capacitance by 49%. The ability to fabricate air-gaps and Ôextended air-gapsÕ was demonstrated, and the capacitance decrease was experimentally verified. Cu/air-gap and extended Cu/air-gap interconnect structures were fabricated using high-modulus tetracyclododecene (TD)-based sacrificial polymer. The aspect ratio of the air-gap was 1.8 and the air-gap was extended 80 nm and 100 nm into the top and bottom interlevel SiO 2 region, respectively. The measured effective dielectric constant (k eff ) of the Cu/air-gap and the extended Cu/air-gap structures with SiO 2 interlevel dielectric was 2.42 and 2.17, respectively. The effect of moisture uptake within the extended Cu/air-gap structure was investigated. As the relative humidity increased from 4% to 92%, the k eff increased by 7%. Hexamethyldisilazane was used to remove adsorbed moisture and create a hydrophobic termination within the air-cavities, which lowered the effect of humidity on the k eff . A dual Damascene air-gap and extended air-gap fabrication processes were proposed and the challenges of using a sacrificial polymer placeholder approach to form air-cavities are compared to other integration approaches of dual Damascene air-gap.

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“…To prevent cracking, a dynamic decomposition recipe that maintains a constant efflux of polynorbornene was employed. This recipe was derived from a thermal gravimetric analysis of polynorbornene performed by Wu et al 9 The dynamic decomposition recipe used in this a͒ Electronic mail: nicolerdevlin@gmail.com experiment for titanium channels is provided in Table I. With this recipe, both the small nanometer sized features and large millimeter sized features decomposed through a 4 m titanium encapsulating layer, as shown in Fig.…”

Section: Fabricationmentioning

confidence: 99%