Optical imaging device and method for reducing dynamic fluctuations in pressure difference
AssigneeCarl Zeiss SMT GmbH
InventorsStefan Hembacher, Bernhard Gellrich, Jens Kugler, Sascha Bleidistel
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Abstract
There is provided an optical imaging device, in particular for microlithography, comprising at least one optical element and at least one holding device associated to the optical element (109), wherein the holding device holds the optical element and a first part (109.1) of the optical element contacts a first atmosphere and a second part (109.2) of the optical element at least temporarily contacts a second atmosphere. There is provided a reduction device at least reducing dynamic fluctuations in the pressure difference between the first atmosphere and the second atmosphere.
Claims22
An optical imaging device comprising
- at least one optical element;
- a first part of said optical element contacting a first atmosphere and a second part of said optical element at least temporarily contacting a second atmosphere, wherein
- a reduction device is provided, said reduction device at least reducing dynamic fluctuations in a pressure difference between said first atmosphere and said second atmosphere, wherein
- said reduction device comprises a control device and an adjustment device connected to said control device;
- said control device is configured to determine a frequency and a first amplitude of first pressure waves within said second atmosphere,
- said adjustment device, as a function of said frequency and said first amplitude of said first pressure waves as well as controlled by said control device, is configured to generate second pressure waves in said second atmosphere in such a manner that said second pressure waves and said first pressure waves interfere to form resulting pressure waves with a resulting amplitude that is one of smaller than said first amplitude and substantially zero,
- a shell structure is adjacent to and at least partially surrounds at least one member selected from the group consisting of said optical element and a holding device that holds said optical element,
- said adjustment device comprising at least one pressure wave generating device mechanically connected to said shell structure and configured to generate said second pressure waves,
- wherein said shell structure is non-pressure tight.
An optical imaging method, wherein
- a projection pattern is imaged onto a substrate using an optical imaging device;
- a first part of an optical element of said optical imaging device contacting a first atmosphere and a second part of said optical element at least temporarily contacting a second atmosphere;
- for reducing an imaging error occurring during imaging said projection pattern onto said substrate and resulting from dynamic fluctuations in a pressure difference between said first atmosphere and said second atmosphere, at least a reduction of said dynamic fluctuations in said pressure difference between said first atmosphere and said second atmosphere being provided, wherein reducing the imaging error comprises:
- determining the frequency and the first amplitude of first pressure waves within said second atmosphere,
- as a function of said frequency and said first amplitude of said first pressure waves, generating second pressure waves in said second atmosphere so that said second pressure waves and said first pressure waves interfere to form resulting pressure waves with a resulting amplitude,
- said resulting amplitude being one of smaller than said first amplitude and substantially zero,
- said second pressure waves being generated via a shell structure that is adjacent to and at least partially surrounding at least one of said optical element and a holding device holding said optical element,
- wherein said shell structure is non-pressure tight.
Dependencies are inferred from the claim text.