Highly selective reactive-ion etching using CO/NH3/Xe gases for microstructuring of Au, Pt, Cu, and 20% Fe–Ni

Abe, Takashi; Hong, Youn Gi; Esashi, Masayoshi

doi:10.1116/1.1612516

Cited by 12 publications

(7 citation statements)

References 7 publications

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“…SIS-modified PS- b -PMMA also enables direct pattern transfer into permalloy (Ni 0.8 Fe 0.2 ) using CO-based plasma etching (Figure a,b) . As in the previous cases, without SIS treatment, the PS- b -PMMA layer does not resist well to plasma etching, and no pattern is transferred (Figure c).…”

Section: Resultsmentioning

confidence: 85%

“…26 As in the previous cases, without SIS treatment, the PS-b-PMMA layer does not resist well to plasma etching, and no pattern is transferred (Figure 4c). Thickness segregation on this sample leads to regions with single and double layers of in-plane PMMA cylinders, facilitating visualization of the efficacy of the mask.…”

Section: ' Experimental Methodsmentioning

confidence: 81%

“…The thicker regions prevent the permalloy from plasma etching, while the thinner, single-layer PMMA cylinders allow permalloy to be etched with nanoscale features. Deeper pattern transfer should be possible using optimized plasma chemistries and also through the use of alternate SIS chemistries such as TiO 2 , which has a large selectivity as compared to permalloy …”

Section: Resultsmentioning

confidence: 99%

“…Deeper pattern transfer should be possible using optimized plasma chemistries and also through the use of alternate SIS chemistries such as TiO 2 , 18 which has a large selectivity as compared to permalloy. 26 Thus, the above method of increasing the etch resistance of PS-b-PMMA enables the direct transfer of nanoscale patterns into several types of technologically relevant substrates. BCPs are intensively studied as a potential method to enhance photolithography for semiconductor manufacturing.…”

Section: ' Experimental Methodsmentioning

confidence: 99%

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Enhanced Block Copolymer Lithography Using Sequential Infiltration Synthesis

et al. 2011

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INTRODUCTIONSelf-assembly of block copolymer (BCP) thin films has been explored extensively as a strategy to make periodic nanostructures. 1À4 Because these nanoscale features can be formed reproducibly and at low-cost, there is tremendous interest in transferring such patterns to functional materials. In particular, BCP films are promising for microelectronics and data storage applications where highly dense and periodic nanoscale patterns are needed over a large area. 5À8 BCP films can self-organize to form nanostructures of various morphologies with tunable length scales. Furthermore, by guiding BCP self-assembly using surface topography, highly regular patterns can be generated over macroscopic area with low defect density. 9,10 Since BCP films with a single layer of laterally ordered domains have a thickness on the order of the domain size, they are generally too thin for transferring patterns into the underlying substrate using plasma etching. Because carbon-based polymer blocks erode quickly in a plasma, the masking BCP film is completely removed before features with significant depth can be transferred. For example, polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA), one of the most widely studied BCPs (including in lithography experiments), has an overall poor etch resistance, and the etch contrast between the blocks is only about two. 11 As a result, the depth that can be etched is only on the order of the thickness of the film at best, which is tens of nanometers in most cases. Significant effort has been invested in developing BCPs containing etch-resistant blocks such as polystyrene-block-polydimethylsiloxane (PS-b-PDMS) 12,13 or polystyrene-block-poly(ferrocenylsilane) (PS-b-PFS), 14À17 but many of these BCPs have poor wetting properties or are difficult to remove after the etching process. The synthesis of these polymers can also be challenging. Furthermore, organometallic blocks (such as PFS) are undesirable for microelectronics manufacturing, a major potential application of BCPs, because the uncontrolled diffusion of metals in a semiconductor can degrade the performance of microelectronic devices.For the reasons stated above, a BCP that is easy to synthesize, applicable over large areas, and resistant to plasma etching remains elusive. To etch high aspect-ratio structures, a common scheme is to first transfer the BCP pattern to an intermediate hard mask layer that provides greater etch resistance. The insertion of a hard mask layer adds complexity and cost to the fabrication process due to complications from stress and adhesion as well as the risk of damaging the underlying substrate during deposition. The interfacial interaction between the hard mask and the BCP may also change dramatically how the BCP self-assembles. Furthermore, transferring the pattern with high fidelity into the hard mask layer still requires etch contrast between the polymer blocks. Consequently, strong etch contrast between the BCP blocks is highly desired, regardless of the overall pattern transfer scheme.In this ...

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Section: Resultsmentioning

confidence: 85%

Section: ' Experimental Methodsmentioning

confidence: 81%

Section: Resultsmentioning

confidence: 99%

Section: ' Experimental Methodsmentioning

confidence: 99%

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Enhanced Block Copolymer Lithography Using Sequential Infiltration Synthesis

et al. 2011

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“…Alternately, a CO/NH 3 mixture has been demonstrated as another option, since it can form carbonyls that are volatile, [331][332][333][334] with some enhancement with the addition of Xe. 335 This process is not entirely chemical, however, and sputtering does take place, as evident from the thick sidewalls of redeposited sputtered material. 336 Another option to avoid patterning tough-to-etch materials is to use damascene structures.…”

Section: E Mram and Ferammentioning

confidence: 99%

Plasma etching: Yesterday, today, and tomorrow

Donnelly¹,

Kornblit²

2013

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

676

422

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The field of plasma etching is reviewed. Plasma etching, a revolutionary extension of the technique of physical sputtering, was introduced to integrated circuit manufacturing as early as the mid 1960s and more widely in the early 1970s, in an effort to reduce liquid waste disposal in manufacturing and achieve selectivities that were difficult to obtain with wet chemistry. Quickly,the ability to anisotropically etch silicon, aluminum, and silicon dioxide in plasmas became the breakthrough that allowed the features in integrated circuits to continue to shrink over the next 40 years. Some of this early history is reviewed, and a discussion of the evolution in plasma reactor design is included. Some basic principles related to plasma etching such as evaporation rates and Langmuir–Hinshelwood adsorption are introduced. Etching mechanisms of selected materials, silicon,silicon dioxide, and low dielectric-constant materials are discussed in detail. A detailed treatment is presented of applications in current silicon integrated circuit fabrication. Finally, some predictions are offered for future needs and advances in plasma etching for silicon and nonsilicon-based devices.

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