Stencil reticle cleaning using an Ar aerosol cleaning technique

Okada, Masashi; Kawata, Shintaro; Sonoda, Y.

doi:10.1116/1.1428270

Cited by 11 publications

(8 citation statements)

References 5 publications

(1 reference statement)

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“…Next, we discuss the small translational motion of the bubbles near the node and antinode. The primary Bjerknes force is expressed as 21 [5] where V is the bubble volume. From Eq.…”

Section: Effect Of Initial Bubble Radius and Initial Bubble Position mentioning

confidence: 99%

Numerical Analysis of Single Bubble Behavior in a Megasonic Field by Non-Spherical Eulerian Simulation

Ochiai

Ishimoto

2014

ECS J. Solid State Sci. Technol.

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The mechanism of particle removal in megasonic cleaning needs to be clarified so that it can be controlled and used to clean nanodevices without causing pattern damage. Single bubble behavior in a standing megasonic wave was analyzed using a compressible locally homogeneous model of a gas-liquid two-phase medium. This simulation is the first step toward understanding the particle removal mechanism in megasonic cleaning. We confirmed that our numerical method simulated the characteristics of bubble translational motion in a standing wave, in which the direction of the movement due to the primary Bjerknes force changed at the resonant radius. When the initial position of the bubble was near a moving wall, even a bubble with a radius smaller than the resonant radius moved toward the pressure node. In the three-dimensional calculations, bubble collapse near a side wall induced a higher pressure on the side wall than the maximum pressure of the megasonic wave. The bubble dynamics calculation with gas diffusion indicated that the effect of the rectified diffusion was small because the effect of the dynamic bubble motion was dominant on a timescale of several milliseconds.Semiconductor cleaning is important because contaminant particles adhering to a wafer surface reduce the quality of the semiconductor device. As the size of semiconductor devices decreases, the size of contaminant particles that can cause fatal defects also decreases. Therefore, better cleaning techniques are required. Furthermore, unconventional materials are increasingly being used to reduce power consumption and improve the speed of semiconductor devices. Conventional RCA chemical cleaning can dissolve these new materials and damage the pattern. Physical techniques for semiconductor cleaning include a cryogenic high-speed spray of micro-solid nitrogen, 1-4 an Ar aerosol method, 5 a CO 2 gas cluster method, 6 and wet laser shockwave cleaning. 7 Megasonic cleaning is a physical cleaning technique where particles are removed by the collapse of cavitation bubbles, acoustic streaming, and the surrounding pressure gradient. 8,9 However, the physical forces resulting from the collapse of cavitation bubbles can cause pattern damage. Thus, control of cavitation bubbles in the megasonic field is essential for removing contaminant particles without pattern damage during the megasonic cleaning of nanodevices.There are many experimental studies of megasonic cleaning, such as analyses of particle removal and pattern damage in deionized water with several dissolved gases 10 and observation of bubble behavior. 11 However, it is difficult to determine the mechanism of particle removal experimentally because it occurs on very small temporal and spatial scales. Therefore, theoretical and numerical studies have also been performed. Deymier et al. calculated the acoustic pressure field around the pattern on a silicon wafer and the shear stress acting on the wafer. 12 Their results suggest that the calculated shear stress is far lower than the shear strength of the silic...

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“…Next, we discuss the small translational motion of the bubbles near the node and antinode. The primary Bjerknes force is expressed as 21 [5] where V is the bubble volume. From Eq.…”

Section: Effect Of Initial Bubble Radius and Initial Bubble Position mentioning

confidence: 99%

Numerical Analysis of Single Bubble Behavior in a Megasonic Field by Non-Spherical Eulerian Simulation

Ochiai

Ishimoto

2014

ECS J. Solid State Sci. Technol.

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“…12) cleaning has been proposed. 12,13) Tooling is the only issue remaining to be resolved for pattern inspection, repair, and cleaning systems. However, how to keep masks particle-free without a pellicle is a serious issue common to all NGL systems.…”

Section: Reticle Infrastructurementioning

confidence: 99%

Electro-Optic Characteristics of a Cooled Deuterated Potassium Dihydrogen Phosphate Crystal

Yasuki

Yoshida

Tokita

et al. 2010

Jpn. J. Appl. Phys.

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The EB stepper is an electron beam projection lithography (EPL) system. The EB stepper system is similar to an optical scanning exposure system with a reticle. Nikon has been developing EB stepper on the basis of the optical stepper design. The field size of the electron optical (EO) subsystem of EB stepper (subfield/(SF)) is 1 mm square on a reticle and 250 µm square on a wafer (demagnification: 4×). For full chip exposure, SF exposures are stitched using electron beam deflection and stage movement. A new type of stage has been developed for EB stepper using air guides and linear motors to achieve a high-throughput target. These subsystems are assembled separately at present. In this paper, preliminary results on EB stepper as an exposure system are reported. Progress on infrastructures for EPL is discussed.

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“…Therefore, wet-cleaning processes used by the mask maker should be taken into account when determining the criteria for complementary splitting of circuit patterns. 13 Since relatively new cleaning methods such as aerosol cleaning 14 and supercritical cleaning 15 are still in the stages of research and development, low-damage recipes based on conventional wet-cleaning processes must be developed.…”

Section: Concurrent Development Schemementioning

confidence: 99%

Litho-and-mask concurrent approach to the critical issues for proximity electron lithography

et al. 2003

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The performance of the LEEPL production tool is discussed from the framework of the litho-and-mask concurrent development schemes to establish the feasibility of proximity electron lithography (PEL) especially for contact and via layers in the 65-nm technology node. The critical-dimension (CD) uniformity of 4.7 nm has been achieved for 90-nm contact holes over the 1x stencil mask. Thus, the mask patterns can be transferred onto the resist layer with CD errors of less than 10%, even if the mask-error enhancement factor (MEEF) of 1.6 is taken into account. The mask manufacturability is improved if the MEEF further decreases via the use of thinner resists. Meanwhile, the overlay accuracy of 21.1 nm has been achieved in mix-and-match with the ArF scanner, with the intra-field error of only 5.1 nm owing to the real-time correction for the mask distortion. Also, the conditions for splitting dense lines into two complementary portions have been determined to avoid the pattern collapse in wet-cleaning and drying processes. The critical length of 2 µm is fairly safe for 70-nm lines if the low-damage drying is employed. The inspection tool based on transmission electron images cannot detect all printable defects without further optimization, hence a future challenge.

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Stencil reticle cleaning using an Ar aerosol cleaning technique

Cited by 11 publications

References 5 publications

Numerical Analysis of Single Bubble Behavior in a Megasonic Field by Non-Spherical Eulerian Simulation

Numerical Analysis of Single Bubble Behavior in a Megasonic Field by Non-Spherical Eulerian Simulation

Electro-Optic Characteristics of a Cooled Deuterated Potassium Dihydrogen Phosphate Crystal

Litho-and-mask concurrent approach to the critical issues for proximity electron lithography

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