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US 6,549,267 B1Granted
Pulse-width extending optical systems, projection-exposure apparatus comprising same, and manufacturing methods using same
AssigneeNikon Corporation
InventorYuji Kudo
Life of this patent
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Abstract
This invention pertains to systems for extending the pulse length of pulsed sources of optical radiation. These systems reduce peak optical pulse power without reducing average optical power. The pulse-width extending systems split optical pulses into pulse portions, introduce relative delays among the pulse portions, and then redirect the pulse portions (or portions thereof) along a common axis. Such pulse-width extending systems are especially useful in projection-exposure apparatus for the manufacture of semiconductor devices where short wavelength, high power optical sources tend to damage optical components.
Claims109
A projection-exposure apparatus for projecting a pattern formed on a mask onto a sensitized substrate, the apparatus comprising:
- (a) a source of radiation operable to emit a pulse of radiation having a peak power;
- (b) a pulse-width extending optical system for extending a duration of the pulse emitted by the source of radiation whereby the peak power is reduced, the pulse-width extending optical system comprising (i) a pulse splitter operable to receive the pulse from the source of radiation and to split the pulse into multiple pulse portions, the pulse splitter comprising a pulse-splitting surface;
- (ii) pulse-delaying optical paths situated relative to the pulse splitter so as to receive the pulse portions and cause the pulse portions to propagate along the pulse-delaying optical paths and become relatively delayed with respect to each other;
- (iii) a pulse recombiner operable to receive the relatively delayed pulse portions from the pulse-delaying optical paths and to direct the relatively delayed pulse portions along a direction so as to form a pulse-width-extended pulse, the pulse recombiner comprising a pulse-directing surface;
- and (iv) a relay optical system situated so that the pulse-splitting surface is imaged onto the pulse-directing surface;
- (c) an irradiation optical system situated so as to receive the pulse-width-extended pulse and illuminate the mask with the pulse-width-extended pulse;
- and
- (d) a projection optical system operable to receive radiation, from the pulse-width-extended pulse, transmitted through the mask and to project the received radiation so as to form an image of the mask pattern on the sensitized substrate.
5 more elements
In a method of manufacturing a semiconductor device in which a pattern is formed on a substrate by irradiating a pattern-defining mask with radiation pulses from a radiation source, and forming an image of the mask pattern on the substrate, an improvement comprising the steps:
- (a) before the radiation pulses irradiate the mask, directing the radiation pulses into a pulse-width extending optical system, the radiation pulses each having a pulse width and a peak radiation power;
- (b) passing the radiation pulses through the pulse-width extending optical system so as to produce pulse-width-extended radiation pulses each having a peak radiation power that is less than the peak radiation power of the radiation pulses from the radiation source;
- (c) directing the pulse-width-extended radiation pulses to the mask;
- (d) irradiating the substrate with the pulse-width-extended radiation pulses from the mask;
- and
- (e) wherein step (b) comprises passing the radiation pulses through a pulse-width extending optical system comprising (i) a pulse splitter operable to receive the radiation pulses from the radiation source and to split each of the radiation pulses into multiple pulse portions, the pulse splitter comprising a pulse-splitting surface;
- (ii) pulse-delaying optical paths situated relative to the pulse splitter so as to receive the pulse portions and cause the pulse portions to propagate along the pulse-delaying optical paths and become relatively delayed with respect to each other;
- (iii) a pulse recombiner operable to receive the relatively delayed pulse portions from pulse-delaying optical paths and to combine and direct the relatively delayed pulse portions along a direction so as to form pulse-width-extended pulses, the pulse recombiner comprising a pulse-directing surface;
- and (iv) a relay optical system that images the pulse-splitting surface onto the pulse-directing surface.
6 more elements
A projection-exposure apparatus for projecting a pattern formed on a mask onto a sensitized substrate, the apparatus comprising:
- (a) a pulse-width extending optical system that includes a pulse-splitting surface that splits a light pulse received from a light source into multiple light-pulse portions, a pulse-delaying optical path that introduces respective delays to the light-pulse portions, a pulse-directing surface that recombines the delayed light-pulse portions to form a pulse-width-extended light pulse having a power, and a relay optical system that images the pulse-splitting surface onto the pulse-directing surface;
- and
- (b) an exposure optical system situated and configured to receive the pulse-width-extended light pulse from the pulse-width extending optical system, direct the pulse-width-extended light pulse to the mask, and transfer the pattern from the mask to the sensitized substrate;
- and wherein
- (c) the delays of the multiple light-pulse portions are selected so that the power of the pulse-width-extended light pulse is reduced to decrease degradation of the exposure optical system.
2 more elements
A method for exposing a sensitized substrate to a pattern defined by a mask, comprising:
- (a) producing a light pulse;
- (b) directing the light pulse through a pulse-width extending optical system to split the light pulse into multiple light-pulse portions and delay each light-pulse portion to produce a pulse-width-extended light pulse, the pulse-width extending optical system comprising (i) a pulse splitter operable to receive the light pulse from the radiation source and to split the light pulse into multiple pulse portions, the pulse splitter comprising a pulse-splitting surface;
- (ii) pulse-delaying optical paths situated relative to the pulse splitter so as to receive the pulse portions and cause the pulse portions to propagate along the pulse-delaying optical paths and become relatively delayed with respect to each other;
- (iii) a pulse recombiner operable to receive the relatively delayed pulse portions from the pulse-delaying optical paths and to combine and direct the relatively delayed pulse portions along a direction so as to form pulse-width-extended pulses, the pulse recombiner comprising a pulse-directing surface;
- and (iv) a relay optical system that images the pulse-splitting surface onto the pulse-directing surface;
- (c) directing the pulse-width-extended light pulse to an exposure optical system;
- (d) irradiating the pattern defined by the mask with the pulse-width-extended light pulse from the exposure optical system;
- (e) imaging the pattern onto a sensitized substrate, and
- (f) delaying each light-pulse portion in the pulse-width extending optical system sufficiently to reduce deterioration in optical properties of the exposure optical system.
6 more elements
An exposure apparatus for transferring patterns from a mask to a substrate, comprising:
- (a) a light source that generates a light pulse;
- (b) a secondary light-source system situated and configured to receive the light pulse, form multiple secondary light sources, and direct light from the secondary light sources to the mask;
- (c) a projection optical system situated and configured to project an image of the pattern from the mask onto a sensitized substrate;
- and
- (d) a pulse-width extending optical system situated to receive the light pulse and configured to direct the light pulse to the secondary light-source system and to extend a pulse length of the light pulse, the pulse-width extending optical system comprising (i) a pulse splitter operable to receive the light pulse from the radiation source and to split the light pulse into multiple pulse portions, the pulse splitter comprising a pulse-splitting surface;
- (ii) pulse-delaying optical paths situated relative to the pulse splitter so as to receive the pulse portions and cause the pulse portions to propagate along the pulse-delaying optical paths and become relatively delayed with respect to each other;
- (iii) a pulse recombiner operable to receive the relatively delayed pulse portions from the pulse-delaying optical paths and to combine and direct the relatively delayed pulse portions along a direction so as to form pulse-width-extended pulses, the pulse recombiner comprising a pulse-directing surface;
- and (iv) a relay optical system that images the pulse-splitting surface onto the pulse-directing surface.
5 more elements
An exposure method for transferring a pattern from a mask to a substrate, comprising:
- (a) providing a light pulse having a pulse length;
- (b) extending the pulse length of the light pulse with a pulse-width extending optical system comprising (i) a pulse splitter operable to receive the light pulse from the radiation source and to split the light pulse into multiple pulse portions, the pulse splitter comprising a pulse-splitting surface;
- (ii) pulse-delaying optical paths situated relative to the pulse splitter so as to receive the pulse portions and cause the pulse portions to propagate along the pulse-delaying optical paths and become relatively delayed with respect to each other;
- (iii) a pulse recombiner operable to receive the relatively delayed pulse portions from the pulse-delaying optical paths and to combine and direct the relatively delayed pulse portions along a direction so as to form pulse-width-extended pulses, the pulse recombiner comprising a pulse-directing surface;
- and (iv) a relay optical system that images the pulse-splitting surface onto the pulse-directing surface;
- (c) forming multiple secondary light sources from the light pulse after step (b);
- and
- (d) exposing the substrate to the pattern from the mask using the multiple secondary light sources.
5 more elements
An exposure apparatus comprising:
- (a) a radiation source configured to emit a pulse of radiation;
- (b) an illumination optical system that is situated to receive the pulse of radiation and configured to direct the pulse of radiation to a mask;
- (c) a projection optical system situated and configured to project an image of the mask onto a substrate;
- and
- (d) a pulse-width-extending optical system situated to receive the pulse of radiation and configured to produce at least two pulse portions having relative delays, the pulse-width-extending optical system including (i) a pulse splitter having either a transmittance T such that 29.3%<T<50% or a reflectance R such that 29.3%<R<50%, and (ii) a relay optical system situated to receive at least one pulse portion and configured to direct the received pulse portion from the pulse splitter back to the pulse splitter and to form an image of the pulse splitter on the pulse splitter.
2 more elements
A method of manufacturing a semiconductor device, comprising:
- (a) providing a radiation source that emits a pulse of radiation;
- (b) providing a pulse-width extending-optical system that divides the pulse of radiation into two or more pulse portions, wherein the pulse portions are relatively delayed with respect to each other, the pulse-width-extending optical system including (i) a pulse-separating surface situated to receive the pulse of radiation and having either a transmittance T such that 29.3%<T<50% or a reflectance R such that 29.3%<R<50%, and (ii) a relay optical system situated to direct a pulse portion from the pulse-separating surface back to the pulse-separating surface and that images the pulse-separating surface onto the pulse-separating surface;
- (c) directing the pulse portions to a mask;
- and
- (d) projecting an image of the mask onto a substrate.
2 more elements
An exposure apparatus comprising:
- a light source unit supplying a light pulse to transfer a pattern formed on a mask onto a photosensitive substrate;
- an illumination optical system arranged in an optical path between said mask and said light source unit, said illumination optical system comprising a uniform illumination unit disposed in an optical path within said illumination optical system so as to perform uniform illumination with respect to the mask;
- and
- a pulse-width extending optical system arranged in an optical path between said light source and said uniform illumination unit, which extends a duration of the light pulse supplied from said light source while decreasing a peak power of the light pulse, said pluse-width extending optical system including an optical surface having a multi-layer coating dividing the light pulse into at least two light pulses.
1 more element
An exposure apparatus comprising:
- a light source unit supplying a light pulse to transfer a pattern formed on a mask onto a photosensitive substrate;
- an illumination optical system arranged in an optical path between said mask and said light source unit, said illumination optical system comprising a uniform illumination unit disposed in an optical path within said illumination optical system so as to perform uniform illumination with respect to the mask;
- and
- a pulse-width extending optical system arranged in an optical path between said light source unit and said uniform illumination unit, which extends a duration of the light pulse supplied from said light source unit while decreasing a peak power of the light pulse, said pulse-width extending optical system including a polarizing beam splitter.
1 more element
An exposure apparatus comprising:
- a light source unit supplying a light pulse to transfer a pattern formed on a mask onto a photosensitive substrate;
- an illumination optical system arranged in an optical path between said mask and said light source unit, said illumination optical system comprising a uniform illumination unit disposed in an optical path within said illumination optical system so as to perform uniform illumination with respect to the mask;
- and
- a pulse-width extending optical system arranged in an optical path between said light source unit and said uniform illumination unit, which extends a duration of the light pulse supplied from said light source unit while decreasing a peak power of the light pulse, said pulse-width extending optical system including a beam converting member that changes a polarized beam condition.
1 more element
An exposure apparatus comprising:
- a light source unit supplying a light pulse with energy of at least 10 mw/cm2 and a pulse width δ[sec] to transfer a pattern formed on a mask onto a photosensitive substrate;
- an illumination optical system arranged in an optical path between said mask and said light source unit, said illumination optical system comprising a uniform illumination unit disposed in an optical path within said illumination optical system so as to perform uniform illumination with respect to the mask;
- and
- a pulse-width extending optical system arranged in an optical path between said light source unit and said uniform illumination unit, which extends a duration of the light pulse supplied form said light source unit while decreasing a peak power of the light pulse, said pulse-width extending optical system divides the light pulse into multiple pulse portions and provides a pulse length of at least 3×108×δ[m] with respect to said divided pulse portions.
1 more element
A method of manufacturing a semiconductor device comprising the steps of:
- supplying a light pulse;
- producing pulse-width-extended radiation pulses which extend a duration of the light pulse while decreasing a peak power of the light pulse;
- performing a uniform illumination with respect to a mask by using a uniform illumination unit;
- and
- transferring a pattern formed on the mask onto a photosensitive substrate;
- wherein said producing step includes a step of using an optical surface having a multi-layer coating dividing the light pulse into at least two light pulses.
3 more elements
A method of manufacturing a semiconductor device comprising the steps of:
- supplying a light pulse;
- producing pulse-width-extended radiation pulses which extend a duration of the light pulse while decreasing a peak power of the light pulse;
- performing a uniform illumination with respect to a mask by using a uniform illumination unit;
- and
- transferring a pattern formed on the mask onto a photosensitive substrate;
- wherein said producing step includes the step of using a polarizing beam splitter.
3 more elements
A method of manufacturing a semiconductor device comprising the steps of:
- supplying a light pulse;
- producing pulse-width-extended radiation pulses which extend a duration of the light pulse while decreasing a peak power of the light pulse;
- performing a uniform illumination with respect to a mask by using a uniform illumination unit;
- and
- transferring a pattern formed on the mask onto a photosensitive substrate;
- wherein said producing step includes the step of using a beam converting member that changes a polarized beam condition.
3 more elements
A method of manufacturing a semiconductor device comprising the steps of:
- supplying a light pulse with energy of at least 10 mw/cm2 and a pulse width δ[sec];
- producing pulse-width-extended radiation pulses which extend a duration of the light pulse while decreasing a peak power of the light pulse;
- performing a uniform illumination with respect to a mask by using a uniform illumination unit;
- and
- transferring a pattern formed on the mask onto a photosensitive substrate;
- wherein said producing step comprises the steps of:
- dividing the light pulse into multiple pulse portions;
- and
- providing a pluse length of at least 3×108×δ[m] with respect to said divided pulse portions.
6 more elements
An exposure apparatus comprising:
- an excimer laser source supplying a light pulse to transfer a pattern formed on a mask onto a photosensitive substrate;
- an illumination optical system arranged in an optical path between said mask and said excimer laser source;
- and
- a pulse-width extending optical system arranged in an optical path between said excimer laser source and said illumination optical system, which extends a duration of the light pulse supplied from said excimer laser source while decreasing a peak power of the light pulse, wherein said pulse-width extending optical system includes a light split member having a light split surface with a reflectance R such that 29.3%<R<50% or a transmittance T such that 29.3%<T<50%.
1 more element
A method of manufacturing a semiconductor device comprising the steps of:
- supplying a light pulse by using an excimer laser source;
- producing pulse-width-extended radiation pulses which extend a duration of the light pulse while decreasing a peak power of the light pulse, said producing step including a step of using a light split member having a light split surface with a reflectance R such that 29.3%<R<50% or a transmittance T such that 29.3%<T<50%;
- directing the pulse-width-extended radiation pulses to a mask;
- and
- transferring a pattern formed on the mask onto a photosensitive substrate.
2 more elements
An exposure apparatus comprising:
- a light source supplying a light pulse;
- an exposure optical system arranged in an optical path between said light source and a photosensitive substrate so as to transfer a pattern formed on a mask onto the photosensitive substrate, said exposure optical system comprising a plurality of refractive optical elements which are made from at least one of fused silica and fluorite;
- and
- a pulse-width extending optical system arranged in an optical path between said light source and said exposure optical system, which extends a duration of the light pulse supplied from said light source while decreasing a peak power of the light pulse so as to maintain an optical performance with respect to said plurality of refractive optical elements.
1 more element
A method of manufacturing a semiconductor device comprising the steps of:
- supplying a light pulse;
- transferring a pattern formed on a mask onto a photosensitive substrate by using the light pulse passing through an exposure optical system comprising a plurality of refractive optical elements which are made from at least one of fused silica and fluorite;
- and
- producing pulse-width-extended radiation pulses which extend a duration of the light pulse while decreasing a peak power of the light pulse so as to maintain an optical performance with respect to said plurality of refractive optical elements before said transferring step.
1 more element
Dependencies are inferred from the claim text.