Determination of local electrostatic forces for EUVL mask chucks

Kalkowski, G.; Peschel, Thomas; Risse, Stefan; Müller, Sandra; Engelstad, Roxann L.; Zeuske, Jacob R.; Vukkadala, Pradeep

doi:10.1016/j.mee.2009.10.010

Cited by 6 publications

(3 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6 To measure the flatness of the pin surface, the e-chuck was supported in a vertical configuration to reduce gravitational effects. The chucking surface consists of a 15ϫ 15 square array of pins covering an area approximately 142.5ϫ 142.5 mm 2 .…”

Section: Description Of the Chuckmentioning

confidence: 99%

Assessing the mask clamping ability of a low thermal expansion material chuck

Zeuske

Vukkadala

Engelstad

et al. 2010

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

View full text Add to dashboard Cite

The successful implementation of extreme ultraviolet lithography (EUVL) for patterning in the sub-32 nm regime will require significant improvements in image placement (IP) accuracy over the next few years. The IP error budget for the mask system is extremely stringent; consequently, the reduction or elimination of all sources of error is essential. One potential source of IP error is the effect of the residual nonflatness of the patterned surface of the mask during exposure scanning. The focus of this article is to characterize the clamping ability of a Coulombic electrostatic pin-type chuck and to assess its ability to adequately flatten an EUVL mask. The chuck was fabricated from low thermal expansion material, with a nonflatness over the pin area of approximately 74 nm. Experimental results illustrate that a highly bowed substrate (1149 and 1047 nm for the frontside and backside nonflatness, respectively) could be chucked flat to less than 100 nm. Numerical models were also used to simulate electrostatic chucking and to predict the final nonflatness of the pattern surface of the mask. Excellent agreement was found between the experimental and numerical results. In addition, the modeling tools developed here can be used to optimize the chuck design parameters and to establish the requirements on nonflatness of both the EUVL substrate and the surface of the chuck

show abstract

Section: Description Of the Chuckmentioning

confidence: 99%

Assessing the mask clamping ability of a low thermal expansion material chuck

Zeuske

Vukkadala

Engelstad

et al. 2010

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

View full text Add to dashboard Cite

show abstract

“…7,8 The effect will be even higher in the case of thin wafer chucking 10 which has also been observed experimentally. 11,12 We will use our analytical model and directly correlate the pin-pitch, chucking pressure and pin-size to the mask OPD/IPD on the front-side. The outline of this paper is as follows: After a short introduction to the problem in Sec.…”

Section: Introductionmentioning

confidence: 99%

Analytical treatment of the deformation behavior of EUVL masks during electrostatic chucking

Brandstetter

Govindjee

2012

SPIE Proceedings

View full text Add to dashboard Cite

A new analytical approach is presented to predict mask deformation during electro-static chucking in next generation extreme-ultraviolet-lithography (EUVL). Given an arbitrary profile measurement of the mask and chuck non-flatness, this method has been developed as an alternative to time-consuming finite element simulations for overlay error correction algorithms. We consider the feature transfer of each harmonic component in the profile shapes via linear elasticity theory and demonstrate analytically how high spatial frequencies are filtered. The method is compared to presumably more accurate finite element simulations and has been tested successfully in an overlay error compensation experiment, where the residual error y-component could be reduced by a factor 2. As a side outcome, the formulation provides a tool to estimate the critical pin-size and -pitch such that the distortion on the mask front-side remains within given tolerances. We find for a numerical example that pin-pitches of less than 5 mm will result in a mask pattern-distortion of less than 1 nm if the chucking pressure is below 30 kPa.

show abstract

“…smaller than a real EUVL mask chuck, but with respect to materials, flatness, pin structured surface, and electrostatic characteristics closely related to a mask chuck prototype previously developed at our institute 3,4 . In particular, the same low thermal expansion materials (LTEM) were used and the same technologies were applied to manufacture a nominally identical pin structure at the surface.…”

Section: Introductionmentioning

confidence: 99%

Electrostatic chucking of EUVL masks: coefficients of friction

et al. 2010

Self Cite

View full text Add to dashboard Cite

In extreme ultraviolet lithography (EUVL), the mask hangs on an electrostatic chuck and is moved laterally during exposition. For proper control of the chucked mask under corresponding inertial forces, static friction of the mask on the chuck is critical and an important input parameter for reliable theoretical modelling.To determine static and dynamic friction values, measurements were performed in vacuum on a mask blank with a test chuck, smaller than a real EUVL mask chuck, but otherwise nearly identical in its characteristics. Experimental results were obtained at various voltages for a materials combination of Low Thermal Expansion Glass (LTEM) for the pin chuck surface and a mask blank with a chromium metal backside metallisation, respectively. Dynamic friction was found to be only marginally smaller than static friction and values in the range from 0.27 to 0.33 were determined for the static friction coefficient under vacuum conditions.

show abstract

Determination of local electrostatic forces for EUVL mask chucks

Cited by 6 publications

References 4 publications

Assessing the mask clamping ability of a low thermal expansion material chuck

Assessing the mask clamping ability of a low thermal expansion material chuck

Analytical treatment of the deformation behavior of EUVL masks during electrostatic chucking

Electrostatic chucking of EUVL masks: coefficients of friction

Contact Info

Product

Resources

About