Possible applications of Lattice Boltzmann Methods to ASML

Semiconductor Lithography problems

Lorentz Workshop 17 February 2011

Ramin Badie, Nico ten Kate

Slide 2 |

About ASML

• ASML produces lithography machines for the semiconductor industry

• Our lithography is based on optical projection critical for high speed high resolution production of ICs

• The latest production lithography machines are based on

immersion lithography using a thin layer of water between the last lens element and the wafer

• Future production is envisaged to be based on EUV technology that involves operation at very low pressure

Slide 3 |

ASML manufactures optical lithography machines;

lithography is at the heart of chip manufacturing

Repeat 30 to 40 times to build 3

dimensional structure

Slide 4 |

PhotolithographyMajor modules inside ASML systems

Slide 5 |

Limit optical projection lithography

• Resolution is described by formula: R = k1 * λ / NAWhereby:

R = half period

λ = wavelength of lightNA = numerical aperture of optics = n * sin(α) k1 = Litho process improvements: tool & mask & resist

• Single exposure: minimum k1 = 0.25

λ0 /n λ0

/nα

0.25 λ0/( n sin(α) )

n = refractive index

Slide 6 |

Extreme UV Lithography

Slide 7 |

Rarefied gas flow and heat transfer in Extreme UV

Lithography

Slide 8 |

Rarefied gas flow and heat transfer in Extreme UV

Lithography

Slide 9 |

DSMC caluclations

Slide 10 |

Modeling

• Conventional use of CFD codes using FEM and FVM with modifications for low pressure are not adequate

• Present DSMC methods give not satisfactory results with respect to the measurements

• A full model for solving gas flow and heat transfer at the

walls would be helpful for finding optimal design rules for this part of the machine

Slide 11 |

Immersion lithography

Lens

Water

Lens

Air

Slide 12 |

Thin film liquid break-up

Redistribution of drop

patterns

Continuous film

fluid

lens

wafer

Scanning stage

Slide 13 |

Evaporation at the meniscus

fluid

lens

wafer

Scanning stage