Suppression of 193-nm photoresist deformation by H2 addition to fluorocarbon plasma in via-hole etching

Yonekura, Kazumasa; Yoshikawa, Kazunori; Fujiwara, Y.; Sakamori, Shigenori; Fujiwara, Nobuo; Kosaka, Takayoshi; Ohkuni, M.; Tateiwa, K.

doi:10.1016/j.tsf.2006.10.037

Cited by 11 publications

(8 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…C 4 F 8 /Ar discharges C 4 F 8 / Ar discharges are widely used for highly selective plasma etching of dielectrics. 12,18,27,32 While the process conditions are adjusted to achieve satisfactory etching results for the dielectric materials, the impact of these adjustments on the PR material and feature profile is often not clear.…”

Section: B Effect Of Fluorocarbon Gas Addition To Ar Dischargesmentioning

confidence: 99%

“…13,15,40 The study of H 2 was also motivated by a prior study that had shown reduced PR roughening for CF 4 / H 2 discharges. 18 We also studied Ar addition to CF 4 / H 2 discharges to investigate the effect of Ar + ion bombardment in conjunction with the CF 4 / H 2 chemistry.…”

Section: A Influence Of Surface Composition On Polymer Etching Ratementioning

confidence: 99%

“…17,18 This is followed by a detailed examination of FC-radical rich to Ar-rich discharges ͑C 4 F 8 / Ar͒ and F-rich to Ar-rich discharges ͑CF 4 / Ar͒. Section III will finish with a detailed compositional analysis of the conditions examined.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dependence of photoresist surface modifications during plasma-based pattern transfer on choice of feedgas composition: Comparison of C4F8- and CF4-based discharges

Engelmann¹,

Bruce²,

Weilnboeck³

et al. 2009

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

View full text Add to dashboard Cite

The authors report a study of the impact of surface chemical factors on etch rates along with surface and line edge roughness introduction for prototypical photoresist (PR) materials and structures during plasma-based pattern transfer employing fluorocarbon (FC) discharges. For selected photoresist materials and model polymers (193nm PR, 248nm, PR, and polymethyladamantyl methacrylate), the influence of bulk polymer properties on plasma durability was clarified by comparing etch rates, surface roughness introduction, and profile evolution of nanostructures. They studied the effects of both fluorocarbon fragment deposition and polymer surface fluorination by gas phase fluorine atoms on plasma etching resistance and surface roughness evolution of the organic materials by comparing discharges fed with C4F8∕Ar or CF4∕Ar∕H2 gas mixtures. The spatial frequency distribution of surface roughness was obtained using fast Fourier transformation of atomic force microscopy data. A graphitic layer was formed for Ar containing discharges on the polymer surfaces. Fluorocarbon deposition on the damaged photoresist affected roughening in two opposing ways: ion-induced mixing with the damaged polymer layer increased surface roughening, whereas for simple FC precursor deposition a reduction in surface roughness was seen. The latter effect was especially important during profile evolution of three-dimensional structures. Fluorination of the photoresist surfaces by fluorine-rich plasma increased polymer etching yields, and for highly fluorinated surfaces inhibited the formation of the graphitic surface layer. The destruction of the adamantyl structure is usually found in fluorocarbon/argon discharges and is a major origin of roughness evolution for 193nm PR materials. Process conditions having high etch yields were found to improve the roughness results of 193nm PR after etch. The fluorination of the photoresist materials prevented the formation of characteristic small scale roughness features at the cost of large scale roughness introduction. Use of low energy density process conditions prevented the introduction of large scale roughness and can be explained by suppression of surface roughness growth by an ion-induced transfer mechanism. Alternatively, CF4∕H2 processing also showed improved roughness results due to a separate layer deposition of the fluorocarbon film on top of the photoresist material. The etch results for all process conditions can be combined in a surface roughening model where the roughening behavior of the film scales linearly with the energy density delivered to the polymer surface during processing. Even for a range of feedgas chemistries, adamantyl-containing polymers show enhanced roughening rates, suggesting that the instability of the adamantyl structure used in 193nm PR polymers is the performance limiting factor for processing these PR materials.

show abstract

Section: B Effect Of Fluorocarbon Gas Addition To Ar Dischargesmentioning

confidence: 99%

Section: A Influence Of Surface Composition On Polymer Etching Ratementioning

confidence: 99%

See 1 more Smart Citation

Dependence of photoresist surface modifications during plasma-based pattern transfer on choice of feedgas composition: Comparison of C4F8- and CF4-based discharges

Engelmann¹,

Bruce²,

Weilnboeck³

et al. 2009

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

View full text Add to dashboard Cite

show abstract

“…Therefore, the weak-point of SOC could be overcome by the H 2 plasma treatment. Hardening technique of the imaging layer by H 2 plasma treatment was reported 7) , but this process had the limitation of pattern shrinkage by hardening. We have to consider only the shrinkage of the film thickness in the MLR with the hardening process and it can be easily compensated by controlling the initial thickness of the SOC film.…”

Section: Discussionmentioning

confidence: 99%

Development of high-performance multi-layer resist process with hardening treatment

et al. 2007

Self Cite

View full text Add to dashboard Cite

In the manufacture of devices beyond the 45 nm node, it is important to employ a high-performance multi-layer resist (MLR) process that uses silicon containing ARC (Si-ARC) and spin on carbon (SOC). We examined an additional hardening process of SOC by H 2 plasma treatment in order to improve the etching durability of the MLR. The dry etching durability of H 2 -plasma-hardened SOC film showed a drastic improvement, while the wiggling features of the MLR without H 2 treatment observed after SiO 2 etching disappeared completely. The hardening mechanism of SOC was analyzed by Fourier transform infrared spectroscopy (FTIR) with gradient shaving preparation (GSP) and Raman spectrometry. The formation of diamond-like amorphous carbon at a depth of approximately 50 nm was observed and was attributed to the improvement in the dry etching durability. In addition, the MLR stack with hardening has good reflectivity characteristics. The simulated reflectivity at the interface between the bottom of the resist and top surface of the MLR stack with hardening below 0.6% was attained over a wide range of Si-ARC thicknesses and hyper NA (~1.3) regions. The measured refractive indices of the hardened SOC film at 193 nm had a high value at the surface; however, they gradually decreased toward the inner region and finally became the same as those of untreated SOC. This might be the origin of the estimated excellent reflectivity characteristics.

show abstract

“…H 2 plasma treatment was performed after the substrate was coated with SOC and baked, as shown in Fig. In addition, Yonekura et al 4 have revealed that H 2 plasma treatment for a 193 nm resist restrains the deformation of the via profile. So far, several evaluations of pattern roughness reduction by plasma treatment have been reported.…”

Section: A Sample Preparationmentioning

confidence: 99%

Improvement of the wiggling profile of spin-on carbon hard mask by H2 plasma treatment

Tadokoro

Yonekura

Yoshikawa

et al. 2008

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

View full text Add to dashboard Cite

Infinitely high selective inductively coupled plasma etching of an indium tin oxide binary mask structure for extreme ultraviolet lithographyThe effects of oxygen plasma on the chemical composition and morphology of the Ru capping layer of the extreme ultraviolet mask blanksThe H 2 plasma treatment for spin-on carbon ͑SOC͒ hard mask in the trilayer resist process is expected to serve as a reliable alternative to single layer resist process for 45 nm nodes and beyond. The authors have investigated this treatment with a view to suppress the deformation of SOC by oxide etching. The wiggling profile of SOC drastically improves due to the formation of a thicker diamondlike amorphous carbon structure by the H 2 plasma treatment with higher-energy hydrogen ions.

show abstract

Suppression of 193-nm photoresist deformation by H2 addition to fluorocarbon plasma in via-hole etching

Cited by 11 publications

References 21 publications

Dependence of photoresist surface modifications during plasma-based pattern transfer on choice of feedgas composition: Comparison of C4F8- and CF4-based discharges

Dependence of photoresist surface modifications during plasma-based pattern transfer on choice of feedgas composition: Comparison of C4F8- and CF4-based discharges

Development of high-performance multi-layer resist process with hardening treatment

Improvement of the wiggling profile of spin-on carbon hard mask by H2 plasma treatment

Contact Info

Product

Resources

About