MODULE FOR A PROJECTION EXPOSURE APPARATUS FOR SEMICONDUCTOR LITHOGRAPHY WITH A SEMI-ACTIVE SPACER, AND METHOD FOR USING THE SEMI-ACTIVE SPACER

Abstract

A module for a projection exposure apparatus for semiconductor lithography includes at least one optical element arranged in a holder. At least one spacer is arranged between the holder and a further holder or a main body. The spacer is designed to semi-actively vary its extent. A method for positioning at least one holder in a projection exposure apparatus for semiconductor lithography includes using a semi-active spacer is to position the holder.

Claims

1. A module, comprising: a holder; an optical element in the holder; and a spacer between the holder and a member selected from the group consisting of a further holder and a main body, wherein the spacer is configured so that: when the spacer is activated by a supply of energy, an extent of the spacer changes from a first extent to a second extent different from the first extent; and after achieving the second extent, when the spacer is de-activated by removing the supply of energy, the spacer maintains the second extent to within 100 nanometers.

2. The module of claim 1, wherein, after achieving the second extent, when the spacer is de-activated by removing the supply of energy, the spacer maintains the second extent to within 20 nanometers.

3. The module of claim 1, wherein, after achieving the second extent, when the spacer is de-activated by removing the supply of energy, the spacer maintains the second extent to within five nanometers.

4. The module of claim 1, wherein the spacer comprises a piezoelectric material.

5. The module of claim 1, further comprising an intermediate element, wherein one of the following holds: the intermediate element is between the holder and the spacer; the member comprises the further holder, and the intermediate element is between the further holder and the spacer; and the member comprises the main body, and the intermediate element is between the main body and the holder.

6. The module of claim 5, wherein the intermediate element comprises an adjustment ring.

7. The module of claim 1, wherein the holder is mounted on the member in a statically determinate manner.

8. The module of claim 7, wherein: the module comprises a plurality of spacers; and for each of the six degrees of freedom, a spacer of the plurality of spacers is between the holder and the member.

9. The module of claim 1, wherein the holder is mounted on the member in a statically overdeterminate manner.

10. The module of claim 1, further comprising an open-loop and closed-loop control device configured to control the spacer to adjust a spacing between the holder and the member.

11. The module of claim 1, wherein the module comprises a plurality of spacers configured so that movement of the spacers deforms the holder, and the deformation of the holder is transmitted to the optical element.

12. The module of claim 1, further comprising a seal between the holder and the member.

13. The module of claim 12, wherein the seal is a gas tight seal.

14. The module of claim 12, wherein the seal surrounds the spacer.

15. The module of claim 12, wherein the seal comprises an O-ring.

16. The module of claim 12, wherein the spacer comprises a washer.

17. The module of claim 12, wherein: the member comprises the main body; the module further comprises a decoupling element between the spacer and the main body; and the decoupling element is stiff in a direction of action of the spacer.

18. The module of claim 1, wherein the member comprises the main body, and the module further comprises a decoupling element between the spacer and the main body.

19. The module of claim 1, wherein the optical element comprises a diffractive optical element or a reflective optical element.

20. An apparatus, comprising: a module, comprising: a holder; an optical element in the holder; and a spacer between the holder and a member selected from the group consisting of a further holder and a main body, wherein the spacer is configured so that: when the spacer is activated by a supply of energy, an extent of the spacer changes from a first extent to a second extent different from the first extent; and after achieving the second extent, when the spacer is de-activated by removing the supply of energy, the spacer maintains the second extent to within 100 nanometers; and wherein the apparatus is a semiconductor lithography projection exposure apparatus.

21. (canceled)

22. A method, comprising: using a spacer to positioning a holder in a semiconductor lithography projection exposure apparatus, wherein the spacer is configured so that: when the spacer is activated by a supply of energy, an extent of the spacer changes from a first extent to a second extent different from the first extent; and after achieving the second extent, when the spacer is de-activated by removing the supply of energy, the spacer maintains the second extent to within 100 nanometers.

23.-26. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Illustrative embodiments and variants of the disclosure are explained in more detail below with reference to the drawing, in which:

[0057] FIG. 1 shows the basic construction of an EUV projection exposure apparatus,

[0058] FIG. 2 shows the basic construction of a DUV projection exposure apparatus,

[0059] FIG. 3 shows a detail view of a first embodiment of the disclosure,

[0060] FIG. 4 shows a further detail view of the disclosure,

[0061] FIG. 5 shows a further embodiment of the disclosure, and

[0062] FIG. 6 shows a further embodiment of the disclosure.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0063] FIG. 1 shows an example of the basic construction of a microlithographic EUV projection exposure apparatus 1, in which the disclosure can find use. An illumination system of the projection exposure apparatus 1 has, in addition to a light source 3, an illumination optical unit 4 for the illumination of an object field 5 in an object plane 6. EUV radiation 14 in the form of optical used radiation generated by the light source 3 is aligned via a collector, which is integrated in the light source 3, in such a way that the radiation passes through an intermediate focus in the region of an intermediate focal plane 15 before it is incident on a field facet mirror 2. Downstream of the field facet mirror 2, the EUV radiation 14 is reflected by a pupil facet mirror 16. With the aid of the pupil facet mirror 16 and an optical assembly 17 having mirrors 18, 19 and 20, field facets of the field facet mirror 2 are imaged into the object field 5.

[0064] A reticle 7, which is arranged in the object field 5 and held by a schematically illustrated reticle holder 8, is illuminated. A projection optical unit 9, illustrated merely schematically, serves for imaging the object field 5 into an image field 10 in an image plane 11. A structure on the reticle 7 is imaged onto a light-sensitive layer of a wafer 12, which is arranged in the region of the image field 10 in the image plane 11 and is held by a wafer holder 13 that is likewise illustrated in part. The light source 3 can emit used radiation in particular in a wavelength range of between 5 nm and 30 nm.

[0065] The disclosure may likewise be used in a DUV projection exposure apparatus 31, which is illustrated in FIG. 2. This uses used radiation in a wavelength range from 100 nm to 300 nm.

[0066] The projection exposure apparatus 31 serves for the exposure of structures on a substrate which is coated with photosensitive materials, and which, in some embodiments, generally consists predominantly of silicon and is referred to as a wafer 32, for the production of semiconductor components, such as computer chips.

[0067] The projection exposure apparatus 31 in this case substantially includes an illumination device 33, a reticle stage 34 for receiving and exactly positioning a mask provided with a structure, a so-called reticle 35, by which the later structures on the wafer 32 are determined, a wafer stage 36 for holding, moving and exactly positioning specifically the wafer 32 and an imaging device, to be specific a projection lens 37, with multiple optical elements 38, which are held by way of mounts 39 in a lens housing 40 of the projection lens 37.

[0068] The basic functional principle in this case provides that an image of the structures introduced into the reticle 35 is projected onto the wafer 32, the imaging generally being on a reduced scale.

[0069] The illumination device 33 provides a projection beam 41 in the form of electromagnetic radiation, which is used for the imaging of the reticle 35 on the wafer 32. A laser, plasma source or the like may be used as the source of this radiation. Optical elements in the illumination device 33 are used to shape the radiation in such a way that, when it is incident on the reticle 35, the projection beam 41 has the desired properties with regard to diameter, polarization, form of the wavefront and the like.

[0070] An image of the reticle 35 is produced by the projection beam 41 and transferred from the projection lens 37 onto the wafer 32 in an appropriately reduced form, as already explained above. In this case, the reticle 35 and the wafer 32 may be moved synchronously, so that images of regions of the reticle 35 are projected onto corresponding regions of the wafer 32 virtually continuously during a so-called scanning operation. The projection lens 37 has a multiplicity of individual refractive, diffractive and/or reflective optical elements 38, such as for example lens elements, mirrors, prisms, terminating plates and the like, wherein the optical elements 38 can be actuated for example via one or more of the actuator arrangements described here.

[0071] FIG. 3 is a schematic illustration of a main body 54, for example the lens housing illustrated in FIG. 2, and of a holder 50, for example the mount illustrated in FIG. 2, wherein the holder 50 includes a flange 51. A semi-active spacer 52 is arranged between the flange and the main body 54. The semi-active spacer is designed as a ring, such that a screw 53, which may for example be designed as an expansion screw, firstly connects the flange 51 and the main body 54, and secondly, the spacer 52 is preloaded. To seal the connection, a seal designed as an O-ring 56 is likewise arranged between the flange 51 and the main body 54. The travels of the semi-active spacers 52 are in this case much shorter than the compression of the seal 56, such that the sealing action is ensured at all times. A further seal may optionally be arranged on the other side of the spacers 52.

[0072] FIG. 4 is a schematic illustration of two holders 50, 50′, wherein a first holder 50 includes a flange 51. Arranged on the second holder 50′ is an intermediate element 57, which is designed for example as a passive spacer and which includes through-holes 58 for screws 53. Arranged between the intermediate element 57 and the flange 51 of the first holder 50 are semi-active spacers 52, which are designed as rings and through the opening of which the screws 53 extend for the purposes of connecting the first 50 and second holder 50′. Likewise arranged between the flange 51 and the intermediate element 57 is a seal designed for example as an O-ring 56′. The intermediate element 57 may, for example after initial assembly of the holders 50, 50′ and a determination of the setpoint spacing of the optical elements, be uninstalled again and reworked. After reassembly, the remaining deviation can be adjusted via the semi-active spacers 52. This has the advantage that the unpredictable deformations as a result of the screw connection of the two holders 50, 50′ can be reduced to a minimum.

[0073] FIG. 5 is a further schematic illustration of a projection exposure apparatus, wherein, for the sake of clarity, the illumination device is not illustrated. The projection optical unit 37 includes an upper lens part 60 including multiple holders 52, a holder 62 designed as a module, and a lower lens part 61 including multiple holders 52. In the event that the module 62 has to be exchanged, the upper lens part 60 is removed and the module 62 is exchanged, wherein the module 62 is aligned relative to the lower lens part 61 via intermediate elements 57 designed as passive spacers. The semi-active spacers 52 described in FIGS. 3 and 4 are arranged on the module 62, onto which, in turn, the upper lens part 60 is assembled. The upper lens part 60 is aligned relative to the module 62 by movement of the semi-active spacers 52, wherein, for example, a statically determinate three-point mounting of the upper lens part 60 on the module 62 permits an adjustment of the tilt about two axes and an adjustment along the longitudinal axis of the projection optical unit.

[0074] FIG. 6 is a schematic illustration of a holder which is designed as a module 72 and which may be used in particular in EUV projection exposure apparatuses. The module 72 is designed for example as a mirror, wherein the module 72 is mounted in a main body 74 so as to be manipulable in six degrees of freedom. For the positioning of the module 72 on the main body 74, six semi-active spacers 52 are arranged on the module 72, wherein only three spacers are visible in FIG. 6 because the others are concealed. The spacers 52 are connected, for the movement thereof, to an open-loop and closed-loop control device 59. For the decoupling of the parasitic movements of the spacers 52 resulting from the movement of the respective other spacers 52, decoupling elements 73 are arranged between the spacers 52 and the main body 75, which decoupling elements are attached to the main body 74 rigidly only in the direction of action of the spacers 52 and are attached flexibly in the five other degrees of freedom.

[0075] In this context, flexible is intended to mean that the rigidity of the decoupling elements is configured to be as low as possible in the context of the design and the technical characteristics of the material used, such as for example yield strengths or flexural strengths. By contrast, rigid is to be understood to mean a greatest possible rigidity in the context of the design and the technical characteristics of the material used.

[0076] The semi-active spacers 52 may, in particular during an initial alignment of the modules 72 in the projection exposure apparatus, be used to position the modules 72 with such accuracy that the further actuators of the projection exposure apparatus, which for the sake of better clarity are not illustrated in FIG. 6, need to use virtually no travel for the alignment of the modules 72 for the purposes of positioning the modules 72 during operation. A feature can be that the actuators, in the case of which the ratio of the travels used during operation to the travels used during the alignment is commonly 1:100, in particular 1:50, in particular 1:10, can, through the use of the semi-active spacers, be configured with shorter travels and thus so as to be less expensive.

LIST OF REFERENCE SIGNS

[0077] 1 Projection exposure apparatus

[0078] 2 Field facet mirror

[0079] 3 Light source

[0080] 4 Illumination optical unit

[0081] 5 Object field

[0082] 6 Object plane

[0083] 7 Reticle

[0084] 8 Reticle holder

[0085] 9 Projection optical unit

[0086] 10 Image field

[0087] 11 Image plane

[0088] 12 Wafer

[0089] 13 Wafer holder

[0090] 14 EUV radiation

[0091] 15 Intermediate field focal plane

[0092] 16 Pupil facet mirror

[0093] 17 Assembly

[0094] 18 Mirror

[0095] 19 Mirror

[0096] 20 Mirror

[0097] 31 Projection exposure apparatus

[0098] 32 Wafer

[0099] 33 Illumination device

[0100] 34 Reticle stage

[0101] 35 Reticle

[0102] 36 Wafer stage

[0103] 37 Projection optical unit

[0104] 38 Optical elements

[0105] 39 Mounts

[0106] 40 Lens housing

[0107] 41 Projection beam

[0108] 50, 50′ Holder

[0109] 51 Flange

[0110] 52 Semi-active spacer

[0111] 53 Preloading mechanism (screw)

[0112] 54 Main body

[0113] 56, 56′ O-ring

[0114] 57 Intermediate element

[0115] 58 Through hole

[0116] 59 Open-loop and closed-loop control device

[0117] 60 Upper lens part

[0118] 61 Lower lens part

[0119] 62 Module

[0120] 72 Module

[0121] 73 Decoupling element

[0122] 74 Main body