Analysis of Coulomb and Johnsen-Rahbek electrostatic chuck performance for extreme ultraviolet lithography

Abstract

The successful implementation of extreme ultraviolet lithography ͑EUVL͒ requires the use of an electrostatic chuck to both support and flatten the mask during scanning exposure. The EUVL Mask and Chucking Standards, SEMI P37 and P40, specify the nonflatness of the mask frontside and backside, as well as the chucking surface, to be on the order of 50 nm peak-to-valley. Thus, characterizing and predicting the capability of the electrostatic chuck to reduce mask nonflatness to meet this specification are critical issues. Details describing the performance of the Coulomb electrostatic chuck have been presented in earlier publications. In this paper, the governing equation identifying the force-gap relationship for a Johnsen-Rahbek ͑J-R͒ chuck is described and compared to the Coulomb response. Using finite element techniques, numerical models of Coulomb and J-R electrostatic chucks have been constructed and evaluated for their clamping performance. The models include the effects of reticle and chuck nonflatness, surface friction, and the finite stiffness of the chuck. Modeling predictions are presented for the two types of chucks. The simulations indicate that using a reticle and chuck ͑Coulomb or J-R style͒ that meet the SEMI standards for flatness can result in a clamped reticle flatness of less than 100 nm. However, there may be a need to increase the chuck stiffness specified in SEMI P40. These results, which provide the first comprehensive comparison of Coulomb and J-R chucks, are currently being used to establish specifications for chuck geometry and to identify the range of flatness variations that can be accommodated with electrostatic chucking.

Preparation and Characterization of Sprayed-Yttrium Oxyfluoride Corrosion Protective Coating for Plasma Process Chambers

“…Furthermore, the YOF coating exhibited superior insulating capability, with an electrical resistivity of 1 × 10 16 Ω•cm and a breakdown voltage of 5.57 kV, implying that YOF is an effective material for insulating applications. Moreover, owing to their large electrical resistivity and high corrosion resistance, YOF coatings meet the requirements of ceramic electrostatic chucks [29,30] (Coulomb type: Electrical resistivity > 10 14 Ω•cm, Johnsen-Rahbek type: Electrical resistivity > 10 10 Ω•cm). Overall, the mechanical and thermal properties of YOF coating are higher than those of the YF 3 coating.…”

Application of electrolaminates for the development of biomimetic morphing unmanned aerial vehicles

“…Even theoretical analyses typically rely on empirical correction factors. 19 The amount of power required to hold the electrolaminate in the clamped state is typically 0.1 mW for each square centimeter of clamping area. More power is required to initially charge the capacitor.…”

Materials with Electroprogrammable Stiffness

“…Materials that use electroadhesion for stiffness modulation often assume the dielectric layers to be fully insulating, but this is not always an accurate representation. [ 50 ] When charge carriers can move through the dielectric layer, electroadhesion occurs via the Johnsen–Rahbek (J–R) effect. [ 46 ] In this case, current flows through the dielectric (e.g., a polyelectrolyte or a semiconducting material) and charges migrate to the surfaces of the dielectric film.…”

“…However, J–R forces dominate when the bulk resistivity of the dielectric material is less than 10 10 Ω cm, and coulombic forces dominate when the bulk resistivity is greater than 10 13 Ω cm. [ 48 ] The J–R effect, which is often utilized in electrostatic chucks in semiconductor manufacturing, [ 48,50 ] has not been utilized for electroadhesive stiffness modulation. As seen in Equation (), J–R attraction can lead to larger electrostatic pressures at a fixed voltage since the interfacial gap g is often much smaller than the thickness of a dielectric film in a coulombic system, [ 50 ] thus making J–R adhesion potentially attractive for electrostatic clutches and laminates.…”

“…[ 48 ] The J–R effect, which is often utilized in electrostatic chucks in semiconductor manufacturing, [ 48,50 ] has not been utilized for electroadhesive stiffness modulation. As seen in Equation (), J–R attraction can lead to larger electrostatic pressures at a fixed voltage since the interfacial gap g is often much smaller than the thickness of a dielectric film in a coulombic system, [ 50 ] thus making J–R adhesion potentially attractive for electrostatic clutches and laminates. J–R adhesion is also independent of dielectric material thickness and relative permittivity, [ 48 ] which could facilitate the use of dielectric materials with increased conductivity, such as aluminum nitride, in the next generation of electroadhesive programmable materials.…”