DE102009025664A1 - Field facet element for assembly of facetted mirror to produce microchip, has reflection front wall defining reflection surface, and extensions defining stack surfaces to stack facet elements, where stack surfaces are adjacent to side walls - Google Patents

Abstract

The facet element (20) has a reflection front wall (26) defining a reflection surface (19) of the facet element, and side walls formed according to a shape of the reflection front wall. Stack extensions (31) are arranged on oppositely lying base body front walls (29, 30), which are connected with one another by the side walls. The stack extensions define flat stack surfaces for stacking of multiple facet elements on top of each other, where the stack surfaces are adjacent to the side walls. Independent claims are also included for the following: (1) a method for producing a facet element (2) a projection exposure system comprising a projection optics (3) a method for producing a structured component.

Description

The The invention relates to a facet element for constructing a facet mirror. Furthermore, the invention relates to a facet mirror with a plurality Such facet elements, a lighting optical system with such Facet mirror, a projection exposure system with such a Illumination optics, a method for producing a micro- Nanostructured device with such a projection exposure system and a device manufactured by such a method.

Facet elements and methods for their preparation are known from the DE 10 2007 008 448 A1 and the references given there.

facet mirror such facet elements can be stacked the facet elements are produced on each other.

It is an object of the invention, the orientation of the stacked Facette elements to each other to simplify.

These The object is achieved by a facet element with the features specified in claim 1.

According to the invention was recognized that stack extensions on the facet primitives offer the possibility to specify defined stacking areas. The stacking extensions can be used to specify the stacking surfaces be processed with high precision, so that the stacked Facet elements can be aligned exactly to each other. The flat stacking surfaces ensure a high Stack accuracy and thus a high alignment accuracy of Facet elements.

stacking surfaces according to claim 2 can be, for example, a common Specify flat reference surface exactly.

Batch processes according to claim 3 avoid alignment problems associated with the connection of separate stack extensions with the facet bases related.

in sections extending stack extensions according to claim 4 leave room for other components, such as stacking extensions adjacent facet elements, for cooling components or for actuators.

At least two stacking extensions according to claim 5 improve the alignment accuracy when Stack the facet elements.

A Through hole according to claim 6 allows the Implementation of mounting elements, such as mounting bolts, via the stacked facet elements are connected together can.

A Coating according to claim 7 can for tolerance compensation in the Specification of exactly aligned stacking surfaces used become. The coating may be a metallic coating, around a silicon coating or a ceramic coating act. The coating can with the help of a CVD (Chemical Vapor Deposition, chemical vapor deposition) method.

One the reflection surface continuing stacking extension after Claim 8 can be used for the reflection of radiation, the not like that reflected from the other reflection surface Radiation is used. For example, by means of the reflection surface Continuing stack extension reflected radiation a control measurement a plant are carried out in such a Facet element is used.

A Arch mold according to claim 9 has been for certain applications the facet element proved to be advantageous. It leaves hereby, for example, a corresponding arcuate Illuminate object field.

The Advantages of a facet mirror according to claim 10 correspond to those those with reference to the inventive Facet element have already been explained.

at a facet mirror according to claim 11 are the requirements of the surface quality of mutually facing side or end walls of the faceted elements reduced.

One maximum distance according to claim 12 leads to a low Loss of total reflection surface of the facet mirror in the area of adjacent stacked facet elements.

A staggered arrangement of the stack extensions according to claim 13 also leads to a small loss of total reflection surface in the area of adjacent to each other over the end walls Facet elements, as between such facet elements not the double, but only the simple width of a stack extension needs to be respected as a distance.

A method according to claim 14 enables an economical production of a facet element according to the invention. Various can be found under the heading EDM (Electrical Discharge Ma Chining) known methods are used, in particular a production by wire EDM.

The Advantages of a lighting optical system according to claim 15, a projection exposure apparatus according to Claim 16, a manufacturing method according to claim 17 and of a device according to claim 18 correspond to those above with reference to the facet element according to the invention and on the facet mirror according to the invention already explained.

embodiments The invention will be described below with reference to the drawing explained.

In show this:

1 schematically a meridional section through a projection exposure system for EUV lithography;

2 schematically a plan view of a field facet arrangement of a field facet element for use in the projection exposure apparatus according to 1 ;

3 schematically a plan view of a pupil facet arrangement of a pupil facet mirror for use in the projection exposure apparatus according to 1 ;

4 in perspective and magnifies a facet element of the field facet element 2 ;

5 a plan view of a reflection surface of the facet element after 4 ;

6 in a to 4 similar representation two columns by side adjacent groups to four of the facet elements after 4 in accordance with the facet arrangement 2 stacked arrangement;

7 a plan view of the reflection surfaces of the facet element arrangement 6 ; and

8th to 10 Supervision of other variants of field facet elements with further versions of facet element arrangements in a for 2 similar representation.

1 schematically shows in a meridional section a projection exposure system 1 for micro-lithography. A lighting system 2 the projection exposure system 1 has next to a radiation source 3 an illumination optics 4 for the exposure of an object field 5 in an object plane 6 , One is exposed in the object field 5 arranged and not shown in the drawing reticle, which is held by a reticle holder, also not shown. A projection optics 7 serves to represent the object field 5 in a picture field 8th in an image plane 9 , A structure on the reticle is imaged onto a photosensitive layer in the area of the image field 8th in the picture plane 9 arranged wafer, which is also not shown in the drawing and is held by a wafer holder, also not shown.

To facilitate the description of positional relationships, a Cartesian xyz coordinate system is shown in selected figures of the drawing. Insofar as this coordinate system is assigned to individual mirrors of the illumination optics, the x and y axes each span a total reflection surface of the mirror. The z-axis in this case is perpendicular to the total reflection surface of the mirror. Instead of these local coordinate systems assigned to the individual mirrors, in the 1 between the object plane 6 and the picture plane 9 used a global coordinate system of the projection exposure system. In the 1 the x-axis runs perpendicular to the plane of the drawing. The y-axis runs in the 1 to the right. The z-direction runs in the 1 down and is perpendicular to the object plane 6 and the picture plane 9 , The x-axes of the global coordinate system and the local coordinate systems run parallel to each other. In the projection exposure, the reticle holder and the wafer holder are displaced synchronized with one another in the y direction, wherein this may be a scan displacement or a stepwise displacement, ie a step displacement. The y-direction is therefore also referred to as the object displacement direction.

At the radiation source 3 It is an EUV radiation source with an emitted useful radiation in the range between 5 nm and 30 nm. It can be a plasma source, for example a GDPP source (plasma generation by gas discharge, gasdischarge-produced plasma) or an LPP source. Source (plasma generation by laser, laser-produced plasma) act. Also, a radiation source based on a synchrotron is for the radiation source 3 used. Information about such a radiation source is the expert, for example in the US Pat. No. 6,859,515 B2 , EUV radiation 10 coming from the radiation source 3 emanating from a collector 11 bundled. A corresponding collector is from the EP 1 225 481 A known. After the collector 11 propagates the EUV radiation 10 through an intermediate focus level 12 before moving to a field facet mirror 13 meets. The field facet mirror 13 is in a plane of illumination optics 4 arranged to the object level 6 is optically conjugated.

The EUV radiation 10 is hereinafter also referred to as illumination light or as imaging light.

After the field facet mirror 13 becomes the EUV radiation 10 from a pupil facet mirror 14 reflected. The pupil facet mirror 14 is in a pupil plane of the illumination optics 4 arranged to a pupil plane of the projection optics 7 is optically conjugated. With the help of the pupil facet mirror 14 and an imaging optical assembly in the form of a transmission optics 15 with mirrors in the order of the beam path 16 . 17 and 18 become reflection surfaces 19 from below described in more detail field facet elements 20 of the field facet mirror 13 (see. 2 and 4 ) in the object field 5 displayed. The last mirror 18 the transmission optics 15 is a grazing incidence mirror.

2 shows an arrangement of the field facet elements 20 on a carrier indicated by dashed lines 21 of the field facet mirror 13 , The field facet elements 20 have in the supervision according to 2 an arcuate reflection surface for the EUV radiation 10 , The field facet elements 20 provide adjacent contiguous portions of a total mirror surface of the field facet mirror 13 represents.

In the arrangement according to 2 are the field facet elements 20 in field facet groups 22 to a plurality of field facet elements arranged one above the other in the y direction 20 grouped. The field facet groups 22 lie in the y-direction in partially mutually offset group columns and in the x-direction in groups. The number of field facet elements 20 per field facet group 22 can be different. In the center of the field facet arrangement according to 2 has a central section 23 of the field facet mirror 13 no field facet element 20 on.

The x / y aspect ratio of the field facet elements 20 in the arrangement after 2 is 13. Even larger or smaller aspect ratios are possible. For example, the x / y aspect ratio may be less than 5, greater than or equal to 5, greater than or equal to 10, greater than or equal to 15, greater than or equal to 20, greater than or equal to 30, greater, or be equal to 40 or greater than or equal to 50.

3 shows an arrangement of pupil facets 24 of the pupil facet mirror 14 , The pupil facets 24 in this arrangement form a plurality of concentric circles around a central area 25 of the pupil facet mirror 14 around.

The number of pupil facets 24 corresponds to the number of field facet elements 20 , Alternatively, the number of pupil facets 24 also on the number of field facet elements 20 differ and in particular be greater than the number of field facet elements 20 , There are more than 100 field facet elements 20 and correspondingly more than 100 pupil facets 24 in front.

4 illustrates the structure of one of the field facet elements 20 , The other field facet elements 20 of the field facet mirror 13 are constructed accordingly, so that it is sufficient, based on the 4 and 5 one of the field facet elements 20 to describe in more detail.

The field facet element 20 has a faceted body 25 with an arcuate reflection end wall that covers the reflection surface 19 forms. The faceted body 25 has according to the arch shape of the reflection end wall 26 concave and convex sidewalls 27 . 28 , On opposite main body end walls 29 . 30 of the faceted basic body 25 that go over the side walls 27 . 28 are connected to each other, are stacking extensions 31 executed. At the main body end wall 29 are two of the pile extensions 31 executed. At the main body end wall 30 are also two of the stack extensions 31 executed. The pile extensions 31 thus extend in sections along the two main body end walls 29 . 30 , The pile extensions 31 define the sidewalls 27 . 28 adjacent flat stacking surfaces 32 . 33 such as 34 . 35 , These stacking surfaces 32 to 35 serve for stacking several facet elements 20 like this in the 6 and 7 is shown by way of example.

In the view of the 5 Reminds the shape of the facet element 20 to a letter Ω drawn apart along the x-axis.

On both sides of the concave side wall 27 of the faceted basic body 25 are the two stacking surfaces 32 and 33 arranged. On both sides of the convex side wall 28 of the faceted basic body 25 are the two stacking surfaces 34 and 35 arranged.

The two stacking surfaces 32 and 33 that over the pile extensions 31 on both sides of the concave front wall 27 are defined lie in one and the same stack level 36 , The two stacking surfaces 34 and 35 the over the pile extensions 31 on both sides of the convex side wall 28 are defined lie in one and the same stack level 37 , The two stack levels 36 . 37 are parallel to each other and have a distance to each other, the extent of the facet body 25 in the y-direction.

The stacking surfaces 32 to 35 are ground with high precision and show deviations from the stack levels 36 . 37 in terms of their flatness and in terms of their parallelism, which are less than or equal to 2 microns.

The pile extensions 31 set the faceted body 25 in one piece. The faceted body 25 and the stack extensions 31 are made of silicon.

The pile extensions 31 each have a through opening extending in the y direction 38 ,

On the stacking surfaces 32 to 35 predetermining sidewalls can be the stack extensions 31 a metallic coating 39 wear. About the metallic coatings 39 can be the default of stack levels 36 . 37 over the stacking surfaces 32 to 35 Fine, that is, given with very low tolerance.

The Indian 4 top left illustrated stacking extension 31 sets edge in one area 19a the reflection surface 19 continued. This edge extension of the reflection surface 19 can be used to one not for object field exposure, but for monitoring the radiation source 3 serving the EUV radiation 10 to reflect. This portion can be supplied to a corresponding monitoring detector.

The 6 and 7 show two columns of adjacent blocks 40 . 41 to four stacked field facet elements 20 , The pile extensions 31 each other over the main body end walls 29 . 30 adjacent facet elements 20 are against each other along these main body end walls 29 . 30 , ie along the z-direction, by the width of the stack extensions 31 arranged offset from one another. Again 7 can be seen clearly, are used for the object field exposure reflection surfaces 19 the over the main body end walls 29 . 30 adjacent facet elements 20 about the extension of exactly one of the stack extensions 31 spaced apart in the x-direction.

The faceted basic body 25 have an arc shaping in the way that the stacked facet elements 20 within one of the faceted blocks 40 . 41 exclusively via the stack extensions 31 and not over the side walls 27 . 28 touch.

A maximum distance A (cf. 7 ) between adjacent reflecting surfaces 19 the inside of one of the blocks 40 . 41 stacked faceted elements 20 is 200 μm. Also, a smaller distance A, for example A = 100 microns, is possible.

The pile extensions 31 can in the manufacture of the facet body 25 the faceted elements 20 be prepared by spark erosion, in particular by wire erosion.

After bolting a stacked field facet group 22 can be the reflection surface 19 opposite end wall for producing a thermal contact with a heat sink, not shown, are still ground together plan.

Based on 8th to 10 will be further examples of the arrangement of facet elements 20 , which correspond to the facet elements 20 after the 1 to 7 over stack extensions 31 stacked may be described. Components which correspond to those described above with reference to 1 to 7 already described, bear the same reference numbers and will not be discussed again in detail.

In the in the 8th to 10 The arrangements shown are the stack extensions 31 not shown in detail.

8th shows another example of a group-wise arrangement of the field facet elements 20 on a carrier 21 of the field facet mirror 13 , The field facet groups or blocks 22 are arranged column by column in five group columns. The field facet groups 22 are arranged symmetrically on the support 21 inscribed in a circular envelope. This also applies accordingly to the arrangement 2 ,

Also in the arrangement 8th lie the field facet elements 20 with the arcuate reflection surfaces 19 in front. In the arrangement according to 8th lie the field facet elements 20 column-wise in the y-direction against each other before. Even with such, in columns in the y-direction staggered arrangement, the stacking extensions in the z-direction to each other according to the arrangement of the 6 and 7 be offset so that there also adjacent columns to the width of exactly one of the stack extensions 31 spaced apart in the x-direction.

9 shows a further variant of an array of field facet elements 20 , In the arrangement according to 9 have the field facet elements 20 no arched, but a rectangular reflection surface 19 , wherein the x / y aspect ratio corresponds to what was previously described in connection with the arcuate field facet elements 20 was explained. In the arrangement according to 9 are a total of four columns, each with a plurality of field facet groups 22 in front. Where in one centrally cruciform section 42 a shading of the field facet mirror 13 by upstream components of the illumination optics 4 takes place, are adjacent field facet groups 22 correspondingly more spaced apart, so in the section 42 no field facet elements 20 available. In the embodiment according to 9 with the rectangular reflection surfaces 19 stand the stack levels 36 . 37 for example, by 50 microns or 100 microns on the then also just executed main body side walls 27 . 28 the faceted body 25 above. This can be done by a corresponding metallic coating of the stacking surfaces 32 to 35 the pile extensions 31 be achieved.

10 shows a further variant of an array of field facet elements 20 on a field facet mirror 13 , Again, the field facet elements 20 rectangular and have an x / y aspect ratio, which in turn is that of the arcuate Feldfacettenelemente 20 corresponds to that explained above. The field facet groups 22 are in the arrangement after 10 arranged offset from each other in columns. In this configuration of field facet groups 22 is a horizontal central section 43 of the field facet mirror 13 expanding in the center, not with field facet elements 20 busy. The pile extensions 31 become with the rectangular field facet elements 20 made as in connection with the arcuate field facet elements 20 explained.

With the help of the projection exposure system 1 At least a part of the reticle is imaged on a region of a photosensitive layer on the wafer for the lithographic production of a microstructured or nanostructured component, in particular a semiconductor component, for example a microchip. Depending on the version of the projection exposure system 1 As a scanner or as a stepper, the reticle and the wafer are synchronized in the y-direction continuously in scanner operation or stepwise in stepper mode.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 102007008448 A1 [0002]
• - US 6859515 B2 [0033]
• - EP 1225481 A [0033]

Claims (18)

Facet element ( 20 ) for constructing a facet mirror ( 13 ) - with a facet basic body ( 25 ) - with a reflection end wall ( 26 ), which has a reflection surface ( 19 ) of the facet element ( 20 ), - with according to the shape of the reflection end wall ( 26 ) shaped side walls ( 27 . 28 ), - being on opposite main body end walls ( 29 . 30 ), over the side walls ( 27 . 28 ), stack extensions ( 31 ) are executed, the side walls ( 27 . 28 ) adjacent flat stacking surfaces ( 32 to 35 ) for stacking such facet elements ( 20 ) define. Facet element according to claim 1, characterized in that stacking surfaces ( 32 . 33 ; 34 . 35 ), via the stack extensions ( 31 ) on either side of one of the side walls ( 27 . 28 ) are defined in one and the same stack level ( 36 ; 37 ) lie. Facet element according to claim 1 or 2, characterized in that the stack extensions ( 31 ) the facet basic body ( 25 ) continue in one piece. Facet element according to one of claims 1 to 3, characterized in that the stack extensions ( 31 ) in sections along the main body end walls ( 29 . 30 ) overreach. Facet element according to claim 4, characterized in that at least two stack extensions ( 31 ) in each case on one of the main body end walls ( 29 . 30 ) available. Facet element according to one of claims 1 to 5, characterized in that at least one of the stack extensions ( 31 ) a passage opening ( 38 ) having. Facet element according to one of claims 1 to 6, characterized in that the stack extensions ( 31 ) at least in sections a coating ( 39 ) exhibit. Facet element according to one of claims 1 to 7, characterized in that one of the stack extensions ( 31 ) the reflection surface ( 19 ) continues. Facet element according to one of claims 1 to 8, characterized by an in one plane arcuate reflection end wall ( 26 ), the side walls ( 27 . 28 ) according to the arc shape of the reflection end wall ( 26 ) are concave and convex. Facet mirror ( 13 ) having a plurality of facet elements ( 20 ) according to one of claims 1 to 9. Facet mirror according to claim 10, characterized by a shape of the facet basic body ( 25 ) such that stacked facet elements ( 20 ) exclusively via the stack extensions ( 31 ) touch. Facet mirror according to claim 10 or 11, characterized by a maximum distance (A) between adjacent reflection surfaces ( 19 ) stacked facet elements ( 20 ) of 200 μm. Facet mirror according to one of Claims 10 to 12, characterized by at least two facet blocks ( 22 . 40 . 41 ) each having at least two facet elements ( 20 ) according to one of claims 1 to 9, wherein stack extensions ( 31 ) to each other via the main body end walls ( 29 . 30 ) of adjacent facet elements ( 20 ) against each other along (z) the main body end walls ( 29 . 30 ) by at least the width of the stack extensions ( 31 ) are offset from one another. Method for producing a facet element ( 20 ) according to one of claims 1 to 9, characterized in that the stack extensions ( 31 ) are produced by spark erosion. Illumination optics ( 4 ) for a microlithography projection exposure apparatus ( 1 ) for illuminating an object field ( 5 ) with illumination light ( 10 ) of a radiation source ( 3 ), characterized by a facet mirror ( 13 ) according to one of claims 10 to 13. Projection exposure apparatus ( 1 ) with an illumination optics ( 4 ) according to claim 15 - with a radiation source ( 3 ) for generating the illumination light ( 10 ), - with a projection optics ( 7 ) for imaging in the object plane ( 6 ) object field ( 5 ) in an image field ( 8th ) in an image plane ( 9 ), - with a reticle holder for holding a structure-bearing reticle to be imaged in the object field ( 5 ), - with a wafer holder for holding a wafer in the image field ( 8th ). Method for producing structured components, comprising the following steps: providing a wafer, on which at least partially a layer of a photosensitive material is applied, providing a reticle having structures to be imaged, providing a projection exposure apparatus, 1 ) according to claim 16, - projecting at least a part of the reticle an area of the layer of the wafer by means of the projection exposure apparatus ( 1 ). Structured component manufactured according to one Method according to claim 17.