Ion implantation change in the chemical structure of a resist

Fujimura, Shigefumi; Yano, Hiroshi; Konno, Jun'ichi

doi:10.1016/0168-583x(89)90902-6

Cited by 13 publications

(7 citation statements)

References 8 publications

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“…This trend implies that ion bombardment drives ions deep into the film and shows that the crust removal mechanism is not a near-surface phenomenon like downstream photoresist removal. For high dose phosphorous implanted photoresist, Fujimura et al 46 identified the presence of a triphenylphosphine compound, so an organic arsenic compound is a possibility. So the dual-mode process transforms the olefinic sp 2 clusters and sp 3 diamondlike car-bon network within the implanted crust into an oxygen-rich organic film.…”

Section: Resultsmentioning

confidence: 99%

Surface characterization of ion-enhanced implanted photoresist removal

Kawaguchi

Papanu

et al. 2006

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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We characterize the chemical constitutents of high dose implanted deep ultraviolet photoresist before and after dual-mode oxygen plasma processing, where a remote rf-plasma source is operated simultaneously with rf bias. Raman spectroscopy indicates that the organic composition of the crust comprises a mixture of sp 2 graphite and sp 3 diamondlike carbon structures. High dose ion implantation reduces the hydrogen content by about 50 at. % as measured by hydrogen forward scattering and explains the reduced optical emission signal intensity observed during crust removal. The crust thicknesses extracted from the secondary-ion-mass spectroscopy profile correspond well to prior scanning electron microscopy characterization ͓Kawaguchi et al., J. Vac. Sci. Technol. B ͑submitted͔͒ and support the existence of a transitional layer between the hardened crust and the underlying photoresist. Angle-resolved x-ray photoelectron spectroscopy analysis of arsenic implanted photoresist shows that dual-mode plasma processing causes substantial oxidation deep into the bulk. This result contrasts with downstream plasma processing, which proceeds by a near-surface mechanism. In addition, surface arsenic levels increase by an order of magnitude, which suggests that ion bombardment does not significantly sputter the dopant.

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Section: Resultsmentioning

confidence: 99%

Surface characterization of ion-enhanced implanted photoresist removal

Kawaguchi

Papanu

et al. 2006

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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“…The more conventional ashing of the resist is sometimes not an option anymore due to the stringent substrate loss specifications and incompatibility with metal gates. 2,3,5) Wet cleans with ammonia hydrogen peroxide mixture (APM) or sulphuric acid hydrogen peroxide mixture (SPM) chemistries are also not viable due to their substrate attacking properties. Hence, new cleaning solutions are continuously being developed for post I/I resist strips.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Post Ion-Implantation Resist Strip with the Background Signal of a Light Scattering Tool

Halder

Vos

Wada

et al. 2010

Jpn. J. Appl. Phys.

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A new method for the fast evaluation of photoresist residue removal efficiency is discussed in this paper. In this method “haze” which is the low frequency component of the background signal of a light scattering instrument is mapped over the entire wafer. Since, the background signal is sensitive to any kind of surface anomaly it can be used as a metric for any kind of surface roughness or residues. The goal of this work was to devise a fast and cheap screening method for photoresist residue removal efficiency. Using this method we show that cleaning solutions can be easily screened for their residue removal efficiencies based on the haze signal of the light scattering instrument. Different ion implantation conditions are checked and also different aerosol spray assisted cleaning conditions are evaluated.

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“…The degradation of photoresist by ion bombardment is a complex phenomenon, which is discussed in few reports. [15][16][17][18][19][20][21][22] Some of them seem even contradictory or difficult to compare, mainly because the results are obtained on different resist systems (resist chemical structure) and/or implantation conditions such as ion species, ion energy, ion dose etc. The chemical modifications in high energy ( $ > 100 keV) and high dose implanted novolak based resists are described in few publications.…”

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confidence: 99%

“…The chemical modifications in high energy ( $ > 100 keV) and high dose implanted novolak based resists are described in few publications. [15][16][17][18][19][20] It has been suggested that the photoresist (PR) is transformed into inorganic disordered carbon by the physical ion bombardment. [16][17][18] This process is referred as "carbonization" of the resist and responsible for crust formation in the implanted top region of the resist.…”

mentioning

confidence: 99%

“…18 Later, Fujimura et al have investigated the chemical modifications in phosphorus implanted novolak resist by solid state nuclear magnetic resonance and X-ray photoelectron spectroscopy (XPS). 19,20 They conclude that the crust layer consists of a crosslinked resist. Moreover, the phosphorus implanted species assist in the cross-linking by forming chemical bonds with the resist.…”

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confidence: 99%

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Degradation of 248 nm Deep UV Photoresist by Ion Implantation

Tsvetanova

Vos

Vereecke

et al. 2011

J. Electrochem. Soc.

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Wet processes are gaining a renewed interest for removal of high dose ion implanted photoresist (II-PR) in front-end-of-line semiconductor manufacturing because of their excellent selectivity towards the wafer substrate and gate materials. The selection of wet chemistries is supported by an insight into the resist degradation by ion implantation. In this work, different analytical techniques have been applied for in-depth characterization of the chemical changes in 248 nm DUV PR after arsenic implantation. A radical mechanism of resist degradation is proposed involving cross-linking and chain scission reactions. The cross-linking of the resist is dominant especially for high doses and energies. It leads to significant depletion of hydrogen and formation of carbon macroradicals that recombine to form C-C cross-linked crust. Moreover, formation of ab-unsaturated ketonic and/or quinonoid structures by cross-linking reactions is suggested. In addition, the dopant species may provide rigid points in the PR matrix by chemical bonding with the resist. For higher doses and energies further dehydrogenation occurs, which leads to formation of triple bonds in the crust. Different p-conjugated structures are formed in the crust by cross-linking and dehydrogenation reactions. No presence of amorphous carbon in the crust is revealed.In the processing of integrated circuits, the source and drain of a p-type and n-type metal-oxide-semiconductor field-effect transistor (MOSFET) are defined by implantation of donor and acceptor ions respectively. During the ion implantation, a photoresist is used as a masking material. The removal of high dose ( $ >1 Â 10 15 at. cm À2 ) and low energy ion implanted photoresist (II-PR) after implantation of ultra shallow extension and halo regions is considered one of the most challenging front-end-of-line (FEOL) processing steps for 32 nm and beyond technology nodes of logic devices. This is due to the difficulties of removing the modified layer (crust) formed on top and the sidewalls of the PR during the ion implantation in combination with the compatibility towards shallow implanted substrates, novel metal gate and high k-materials. Commonly used resist strip processes such as fluorine-based dry plasma ash and hot sulfuric/peroxide mixtures induce unacceptable levels of oxidation and material loss. 1-4 Alternative cleans are being developed for removal of II-PR. [5][6][7][8][9][10][11][12][13][14][15] In order to design approaches for selective stripping of II-PR a more profound insight into the resist degradation induced by ion implantation is needed.The degradation of photoresist by ion bombardment is a complex phenomenon, which is discussed in few reports. 15-22 Some of them seem even contradictory or difficult to compare, mainly because the results are obtained on different resist systems (resist chemical structure) and/or implantation conditions such as ion species, ion energy, ion dose etc. The chemical modifications in high energy ( $ > 100 keV) and high dose implanted novolak based resis...

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Ion implantation change in the chemical structure of a resist

Cited by 13 publications

References 8 publications

Surface characterization of ion-enhanced implanted photoresist removal

Surface characterization of ion-enhanced implanted photoresist removal

Evaluation of Post Ion-Implantation Resist Strip with the Background Signal of a Light Scattering Tool

Degradation of 248 nm Deep UV Photoresist by Ion Implantation

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