Ion beam exposure characteristics of resists: Experimental results

Hall, Thomas M.; Wagner, Alfred; Thompson, L. F.

doi:10.1063/1.331261

Cited by 105 publications

(29 citation statements)

References 9 publications

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“…Based on this finding, the authors suggested that the energy density in the track, and not the total deposited energy is a measure of the ion's efficiency in modifying the film. Similar ideas were raised and discussed in more detail in the study of the exposure of polymer resists to 1.5 MeV H ϩ , He ϩ , and O ϩ ions 19 and in subsequent studies 5,6,20 for other polymeric systems. It should be noted that a different behavior was found for polystyrene 21,22 and PMDA-ODA ͑Ref.…”

Section: Introductionmentioning

confidence: 87%

“…The need to consider the ion track structure in order to understand the damage induced in polymers by ion beams has been pointed out in the pioneering studies on exposure of resists 19 and electrical properties of ion-beam-irradiated organic films. 8 It was observed that 1 MeV He ϩ is around 50 times less efficient in producing resistivity drop in NiPC compared to 1 MeV Ar ϩ , although their (dE/dx) e differ by only a factor of 4.…”

Section: Introductionmentioning

confidence: 99%

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Chemical damage in poly(phenylene sulphide) from fast ions: Dependence on the primary-ion stopping power

et al. 1996

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Thin poly͑phenylene sulphide͒ foils were bombarded with fast atomic ions ͑ 4 He, 12 C, 16 O, 32 S, 79 Br, 127 I͒ in the energy range between 2.5 to 78 MeV. In order to maintain the same ion track size for all impacting ions, their initial velocity was kept constant at 1.1 cm/ns. Under these conditions the deposited energy density in a single ion track changes as a result of the varying stopping power (dE/dx) of the projectiles in the material. Fourier transform infrared spectroscopy and UV-visible spectroscopy were used to characterize the irradiated targets. Damage cross sections ͑ ͒ for different chemical bonds, such as C-S and ring C-C bonds, are extracted from the IR data. For all analyzed IR bands, the values of scale roughly with the square of dE/dx ͑energy density in a single ion track͒. The absorption of the irradiated samples in the visible and UV region increases as a function of fluence. The rate of increase of absorption at a particular wavelength scales also as (dE/dx) n with nϷ2. The observed nonlinear dependence of the damage cross sections on the deposited energy density is considered in the light of two models: a statistical model based on the fluctuations of the energy deposited by the primary ions ͑hit theory͒ and an activation ͑thermal spike͒ model. It is found that the damage cross section is not determined directly by the initial deposited energy density distribution. The best agreement between experiment and theory is obtained when transport of the deposited energy occurs.

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Section: Introductionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Chemical damage in poly(phenylene sulphide) from fast ions: Dependence on the primary-ion stopping power

et al. 1996

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“…Taking into account the mass density of the polymer film (-3) and the fraction of the -2 gm film that contains unpaired spins (-1/7) leads to a rough estimate of -5 x 1020 spins/cm 3 for PPO implanted to 10 1 6 cm-2 with 200 keV "°Br ions. A comparison of this spin density with the carrier density deduced from the optical transmission data suggests that only a fraction of these carriers have unpaired spins [14].…”

Section: Discussionmentioning

confidence: 99%

“…Of significance is the higher sensitivity of the polymer (by -2 orders of magnitude) to ion beams relative to electron beams, so that ion beam lithography is feasible at fluences of less than 10 cm- [3]. For positive resists (e.g., PMMA), ion implantation results in scission of the molecular chains, while for negative resists (e.g., polystyrene), implantation results in crosslinking of polymer chains.…”

Section: Acmmentioning

confidence: 99%

Ion Implantation of Polymers

1983

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Ion implantation provides a mechanism for radically modifying the electronic and transport properties of a variety of polymers that are normally insulating.By using masks and tailoring the implanted species and ion energies, conducting paths in an insulating medium can be fabricated between specific reference points, an application of obvious relevance to the microelectronics industry.Specific results are reported for modification of the structure, electrical conductivity, thermoelectric-power, optical transmission and electron spin resonance for several polymers under a variety of implantation conditions.The temperature and frequency dependence of the conductivity suggest a onedimensional variable range hopping mechanism for conduction along the polymer chains. Comparison is made between implantation in the 200 keV and 2 MeV energy ranges.

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“…11 It is easily visible and can be followed even by the naked eye in the film. At this very high fluence the The financial support from C.N.R.…”

mentioning

confidence: 98%