A metal lift-off process through hyperbolic undercut of laser heat-mode lithography

Wang

et al. 2022

Chin. Opt. Lett.

An AgGeSbTe thin film is proposed as a negative heat-mode resist for dry lithography. It possesses high etching selectivity with the etching rate difference of as high as 62 nm/min in CHF 3 =O 2 mixed gases. The etched sidewall is steep without the obvious lateral corrosion. The lithographic characteristics and underlying physical mechanisms are analyzed. Besides, results of X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy further indicate that laser irradiation causes the formation of Ge, Sb, and AgTe crystals, which is the basis of etching selectivity. In addition, the etching selectivity of Si to AgGeSbTe resist is as high as 19 at SF 6 =Ar mixed gases, possessing good etching resistance. It is believed that the AgGeSbTe thin film is a promising heat-mode resist for dry lithography.

Section: Resultsmentioning

confidence: 95%

“…However, wet development is adopted in heat-mode lithography, which readily results in the undercut of resist and, therefore, the pattern collapse [19] . At the same time, wet development will also readily cause resist swelling, influencing the pattern fidelity.…”

Section: Introductionmentioning

confidence: 99%

AgGeSbTe thin film as a negative heat-mode resist for dry lithography

Wang

et al. 2022

Chin. Opt. Lett.

“…Under laser irradiation (exposure), the as-deposited AIST can be changed to the crystalline state. , After development with the alkaline solution, the uncrystallized part of the resist film can be removed Figure a,b shows the two-dimensional (2D) and cross-sectional AFM images of the developed AIST film, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…20,21 After development with the alkaline solution, the uncrystallized part of the resist film can be removed. 22 Figure 2a,b shows the two-dimensional (2D) and cross-sectional AFM images of the developed AIST film, respectively. The AIST grating structure with a thickness of about 70 nm was formed on the Cr surface and the halfpitch (HP) of the grating is about 200 nm, which is quite smaller than the writing wavelength (405 nm).…”

Section: Resultsmentioning

confidence: 99%

Nanoscale-Patterned Cr Films by Selective Etching Using a Heat-Mode Resist: Implications for X-ray Beam Splitter

Liu

Wei

et al. 2021

ACS Appl. Nano Mater.

Self Cite

Nanoscale-patterned chromium (Cr) metal structures are widely used in a large variety of semiconductor processing fields. These structures are usually fabricated via the direct etching method. Owing to the drawbacks of traditional lithography techniques (such as electron beam, ion beam, and scanning probe lithography), it is still a high-cost and complex work to accomplish nanoscale structure fabrication. In this paper, through laser heat-mode lithography, a chalcogenide AgInSbTe (AIST) film is chosen as the dry-etching resist to fabricate a series of arbitrary micro/nanostructures on the Cr film. The etching mechanism from the AIST resist to the Cr mask under the Cl2/O2-based gases has been elucidated through energy-dispersive X-ray spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. A grating pattern with a minimum pitch of 300 nm has been achieved on the Cr mask, and successfully transferred onto a diamond substrate as an X-ray beam splitter. This work provides an effective method for nanoscale structure fabrication and clarifies the antietching mechanisms of AIST resist films under Cl-based plasma etching.

“…The development of the AIST resist is generally carried out in a solution of 17% ammonium sulfide. [22,23] However, hydrolysis of the ammonium sulfide releases toxic and corrosive hydrogen sulfide gas, which causes serious air pollution and potential danger to operators. Furthermore, this photoresist development process not only has a low etching rate, but also generates inhomogeneous structures.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Strategy for High‐Resolution Nanostructures in Laser‐Heat‐Mode Resist Toward Next Generation Diffractive Optical Elements

Wang

Wen

et al. 2022

Small

Self Cite

For achieving high‐resolution nanostructures for next‐generation diffractive optical elements (DOEs) using an environmentally friendly process, an electrochemical development strategy is proposed and developed using AgInSbTe‐based laser heat‐mode resist (AIST‐LHR). Based on the electrical resistivity difference of amorphous and crystalline phases for this resist, an etching selectivity ratio of ≈30:1 (i.e., the etch ratio between the amorphous and crystalline ones) is achieved through the oxidation of Fe3+ ions with the assisted pitting activation etching using Cl− ions in an acid medium. Nanostructures with a minimum feature size down to 41 nm are successfully generated, including grating patterns, meta‐surface optical structures, gears, and English characters. Using a post‐plasma etching process, the nanostructures are successfully transferred from the AIST‐HLR onto silica substrate, and X‐ray grating patterns with a line space of 80 nm are created as a demonstration for its potential applications in DOEs.