Kinetic theory of bombardment induced interface evolution

Jurgensen, Charles W.

doi:10.1116/1.584518

Cited by 20 publications

(21 citation statements)

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“…The silylated etch rate for the first five minutes of etching was 106 A/mm, but for the following 3 minutes of etching was 72 A/mm. The lower silylated etch rate as the etch proceeds may be due to the initial thickness loss of silylated resist as the SiO layer is formed, after which the etch rate drops as the resist enters the "steady-st.ate" etch regime [18] 3.…”

Section: Selectivity and Mask Erosion Ratementioning

confidence: 98%

<title>Evaluation of liquid silylated resists for 213-nm exposure</title>

Hutchinson

Kalpakjian

Schenker

et al. 1993

Advances in Resist Technology and Processing X

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We explore the bulk and imaging properties of two commercially available resists, Shipley SAL-601 and AZ 5214 to 213 nm radiation operating in a liquid silylation mode. We use FTIR and thickness measurements to characterize the silicon uptake process, and explore the use of high frequency RIE etching of silylated resists to increase selectivity and reduce post-etch residues. We demonstrate sub quarter micron lithography using 213 nm exposure of a liquid silylation resist process etched in a 60 MHz 02 plasma.

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Section: Selectivity and Mask Erosion Ratementioning

confidence: 98%

<title>Evaluation of liquid silylated resists for 213-nm exposure</title>

Hutchinson

Kalpakjian

Schenker

et al. 1993

Advances in Resist Technology and Processing X

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“…This assumption is consistent with the polymer etching results that are summarized in section II of this paper. The etching yield of the organic planarizing layer is assumed to be proportional to bombardment energy as found by Visser and Baggerman [12] and by Jurgensen and Rammelsberg [13]. The planarizing layer yield is assumed to be independent of angle.…”

Section: Introductionmentioning

confidence: 99%

Application of the Kinetic Theory of Bombardment Induced Interface Evolution to the Pattern Transfer Step in Multi-Layer Lithography

Jurgensen

Shaqfeh

1990

SPIE Proceedings

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We have formulated a kinetic theory of bombardment induced interface evolution to describe etching by an axisymmetric angular distribution of energetic particles where the volume removed per particle is a function of energy and angle relative to the surface normal. Kinetic theory relates the angular distribution to the pressure, the voltage drop across the plasma sheath, the sheath thickness, and the cross sections describing the collision processes. The resulting interface evolution equation is a nonlinear partial differential equation that may be reduced to a coupled set of ordinary differential equations by the method of characteristics. Additional simplifications arise in two special cases that are relevant to the pattern transfer step in multi -layer lithography. One of these simplifications occurs when the yield is independent of angle as expected for the thermal spike mechanism of bombardment induced chemically assisted etching. This case applies to the planarizing layer in multi -layer lithography where the etching rate is proportional to the energy flux delivered by bombarding particles to a given point on the surface. Analysis of this case shows that shadowing of the angular distribution by adjacent features causes proximity effects in line etching and aspect ratio dependent etching rates in trench etching. For angle dependent yields, another simplification applies to regions that are not shadowed by a remote part of the surface. Analysis of this case shows that facet edges (slope discontinuities) will spontaneously develop from smooth initial conditions. Etching masks are not significantly shadowed by adjacent features, so this case describes mask erosion by physical sputtering mechanisms which are characterized by strongly angle dependent yields. Together these cases allow a complete description of the pattern transfer step in bi -layer lithography. We discuss the effect of mask selectivity, mask wall angle, trench aspect ratio, and etching conditions on etching profiles and process latitudes for the pattern transfer step in multi -layer lithography. ABSTRACTWe have formulated a kinetic theory of bombardment induced interface evolution to describe etching by an axisymmetric angular distribution of energetic particles where the volume removed per particle is a function of energy and angle relative to the surface normal. Kinetic theory relates the angular distribution to the pressure, the voltage drop across the plasma sheath, the sheath thickness, and the cross sections describing the collision processes. The resulting interface evolution equation is a nonlinear partial differential equation that may be reduced to a coupled set of ordinary differential equations by the method of characteristics. Additional simplifications arise in two special cases that are relevant to the pattern transfer step in multi-layer lithography. One of these simplifications occurs when the yield is independent of angle as expected for the thermal spike mechanism of bombardment induced chemically assisted etching. This case ap...

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“…A bottomanti-reflective coating was applied prior to photo resist spinning, which promoted the adhesion of small dots upon resist development. DRIE using SF 6 and O 2 during the etching phases and C 4 F 8 during the passivation phases was optimized (SPTS, Pegasus). The passivation phase was constantly 1 s, while the etch phase was linearly ramped from 3.2 to 3.4 s during the 32 min etching process including 450 cycles.…”

Section: B Microfabricationmentioning

confidence: 99%

“…1(a). 6,7 Moreover, as ions enter trenches or holes, ion deflection (ID) toward the sidewalls occurs, [8][9][10] e.g., by the attraction of ions by their image charges. 11 An uncollimated ion bombardment promotes ion/wall collisions, resulting in local sputtering of the passivation layer, partial protection breakthrough, a finite lateral etch rate, and nonvertical sidewalls.…”

Section: Introductionmentioning

confidence: 99%

Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses

Stöhr

Michael-Lindhard

Hübner

et al. 2015

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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O. (2015). Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses. Journal of Vacuum Science and Technology. Part B. Microelectronics and Nanometer Structures, 33(6), [062001]. DOI: 10.1116/1.4931622 Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses This article describes the realization of complex high-aspect ratio silicon structures with feature dimensions from 100 lm to 100 nm by deep reactive ion etching using the Bosch process. As the exact shape of the sidewall profiles can be crucial for the proper functioning of a device, the authors investigated how sacrificial structures in the form of guarding walls and pillars may be utilized to facilitate accurate control of the etch profile. Unlike other sacrificial structuring approaches, no silicon-on-insulator substrates or multiple lithography steps are required. In addition, the safe removal of the sacrificial structures was accomplished by thermal oxidation and subsequent selective wet etching. The effects of the dimensions and relative placement of sacrificial walls and pillars on the etching result were determined through systematic experiments. The authors applied this process for exact sidewall control in the manufacture of x-ray lenses that are very sensitive to sidewall shape nonuniformities. Compound kinoform lenses for focusing hard x-rays with structure heights of 200 lm were manufactured, and the lenses were tested in terms of their focusing ability and refracting qualities using synchrotron radiation at a photon energy of 17 keV. A 180 lm long line focus with a waist of 430 nm at a focal length of 215 mm was obtained.

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Kinetic theory of bombardment induced interface evolution

Cited by 20 publications

References 0 publications

<title>Evaluation of liquid silylated resists for 213-nm exposure</title>

<title>Evaluation of liquid silylated resists for 213-nm exposure</title>

Application of the Kinetic Theory of Bombardment Induced Interface Evolution to the Pattern Transfer Step in Multi-Layer Lithography

Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses

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