KR100334147B1 - Lighting units for optical systems with reticle-masking system - Google Patents

Abstract

The present invention relates to an illumination system for an optical system, in particular a microlithographic projection-exposure installation, comprising a glass rod (5) for light integration, wherein a reticle masking system (REMA) 51 is provided on the glass rod (5). It was installed at the outlet end of the.

Description

Lighting equipment for optical systems with reticle-masking system

The present invention relates to an illumination device for an optical system, an illumination device for a microlithography projection-exposure system, having a reticle-masking system.

One projection-exposure can be used to manufacture a variety of microchips, in which case the format of the masks for the reticle can vary. Thus, an accurate variable limit of the lighting position relative to the reticle must be planned, or lighting errors may occur. Devices as close as possible to the reticle prohibit its operation and do not meet the requirement to be a high resolution structure for the edge sharpness of the aperture. Thus, it is known to provide an additional intermediate field plane in the illumination beam path and to ensure that the reticle masking system is correctly positioned in the intermediate field plane. The additional lenses required therefore require considerable effort and space for additional equipment due to the given conditions associated with imagefield, aperture, homogeneity and chromatic aberration rejection.

EP 0 297 161 A1 discloses that for a projection-exposure installation having a light conductor-glass rod in an illumination beam path, a pass filter can be installed after the glass rod. This is clearly for developing homogeneity, not for shading.

It is therefore an object of the present invention to provide a reticle masking system having more advantages and at a lower cost.

The above object is achieved by providing a glass rod for condensing and providing a reticle masking system at an outlet end of the glass rod in the lighting apparatus according to the preamble having the features of claim 1. In the case of a lighting device according to the premise, a honeycomb condenser for the uniformity of light distribution is common. Or a glass rod can take over the function. At the exit end, the fact that there is an intermediate field plane used for reticle masking is used. No additional measures for the generation of intermediate field planes are also necessary.

Preferred embodiments are disclosed in the dependent claims. The contents of paragraphs 2, 3 and 13 to 19 are also described in patent application DE 44 21 053.1 "lighting device" by the same person, the same applicant and the inventor.

The contents of paragraphs 4 to 12 are also described in the patent application DE 43 42 424 of 13 December 1993 on which the priority claims are based. The disclosures of these two applications are also part of the present application.

1 is also attached and described in the same patent application described above.

1 shows an embodiment of a lighting apparatus for projection-lithography having a resolution of 1 μm or less according to the invention, for example for the manufacture of integrated circuits.

A lamp 1, which is a 365 nm wavelength mercury short-arclamp for i-line, is placed at the focal point of the elliptical mirror 12, and the elliptical mirror 12 carries out the emitted rays of the second focus 121. Collect on.

Unlike usual, the shutter 13 is installed outside the focus 121, and the distance to the vertex of the oval mirror 12 is about 5 to 20% preferably 10% more than the distance to the vertex of the focus 121. Big. Thereby, the secondary light source formed there is more homogeneous and the partial coherence effect of the illumination on the optical imaging is improved. Thus, a special mixing device for this can be saved. This measure is equally applicable to conventional lighting equipment.

You may use a UV laser as a light source.

The following objective lens 2 is composed of a first lens group 21, a concave first axon 22, a convex second axon 23 and a second lens group 24. The adjusting means 231 and 241 enable the axial movement of the elements of the axicon 23 and the second lens group 24. As a result, the mutual spacing of the axicones 22 and 23 can be adjusted to not only change the annular opening characteristic, but also a zoom effect for the variation of the illuminated pupil diameter and coherence coherence σ can be obtained.

The pupil intermediate plane 3 is followed by a second objective lens 4, which causes light rays to be collected into a glass rod 5 of about 0.5 m in length. The exit of the glass rod 5 is an intermediate field plane, in which a masking system 51 is arranged, which is provided in place of a conventional REMA (reticle masking) system. Thus, there is no need to provide additional conventional intermediate field planes for REMA systems with expensive lens groups.

The formation of the other reticle masking system 51 corresponds to a conventional precision mechanical engineering configuration. However, it should be noted that the limit line runs exactly in the plane. It is desirable to have a sharp aperture slanted symmetrically to the optical axis. This is because reflected light from those surfaces can effectively escape the beam path of the lighting device.

The following objective lens 6 projects an intermediate field plane with a masking system 51 on a reticle 7 (mask, lithographic template) and may contain a first lens group 61, a filter or an aperture. Pupil-intermediate plane 62, second and third lens groups 63 and 65 and diversion reflecting mirror 64 therebetween, and the diversion reflecting mirror 64 allows for a large illumination device (approximately 3 m long). Can be configured horizontally and the reticle 7 can be vertically supported.

2A and 2B show a mercury short-arclamp as the light source 1 ', which collects the luminous flux from the four collectors 21'-24' in a large spatial angle range, respectively. Therefore, most of the light rays are supplied to the four light conductors 31'-34 '. The photoconductors 31'-34 'are configured as cross-sectional transducers, and the exit faces thereof are annular segments. To further homogenize the light intensity across the exit face, the light conductors 31'-34 'are combined, for example, with statistically mixed individual fibers. In addition, the inlet end surface can be made suitable for light distribution.

Otherwise, illumination of the light conductors 31'-34 'can also be realized by means of a laser having a light expanding optics and a pyramid reflector which is a geometric light splitter. In this case the laser is for example an excimer laser that emits UV.

Each of the four optical conductors 31'-34 'has an exit surface composed of a relay optical device 41'-44', a first switching reflector 511'-514 'and a second switching reflector 521'-. Units 524 'are connected respectively. These units can be adjusted or scanned respectively radially and azimuthally by the adjusting mechanism 541'-544 ', including the connecting ends of the flexible conductors 31'-34'. The controller 100 'controls the adjusting mechanism 541'-544'.

Light rays reaching the entrance face 71 'of the glass rod 7' from the four diversion reflecting mirrors 521'-524 'via the collecting mirror 6' form an image. This entrance surface 71 'is present in the pupil plane P of the lighting device, and each of the four units can illuminate each part of the quadrants of the entrance surfaces according to the adjustment of the adjusting mechanism 541'-544'. . The four beams captured by the collectors 21'- 24 'are also geometrically combined here to form an effective secondary light source.

On the exit surface 72 'of the glass rod 7' there is a field plane F, in which the reticle masking system 8 'and an adjustable aperture are arranged in accordance with the invention. The reticle masking system REMA is adjusted as necessary by the adjusting means 81 '.

The reticle masking system 8 'at this position saves the cost of preparing additional field planes exclusively for the reticle masking system, compared to known methods.

Subsequent mesomorphism system 9 'consists of a pupil plane P 93' and a previous inter-masking system 91 'and subsequent plane mirrors and symbolically shown beam switching sections. It is an objective lens having a 92 ', and the planar mirror enables a more compact assembly as a whole. Then, the reticle 10 to be illuminated is in the field plane F.

Patent application DE-P 43 42 424 is described, including FIGS. 2a and 2b.

Subsequent projection objectives and wafers to be illuminated are not shown since they are known.

1 is a schematic diagram of one embodiment having a Zoom-Axicon,

2a is a schematic side view of an embodiment having an adjustable reflector for the selection of illumination type,

FIG. 2B is a plan view of FIG. 2A.

* Explanation of symbols for main parts of the drawings

1: mercury stage-arc lamp 2: objective lens

3: pupil middle plane 5: glass rod

13: shutter 22, 23: axicon

31, 32, 33, 34: optical conductor 51: reticle masking system

100: control unit

Claims (20)

In an optical system having a reticle-masking system (51), in particular in a lighting apparatus for microlithography projection-exposure equipment, A glass rod (5) for collecting light, and the reticle masking system (51) is provided at the exit end of the glass rod (5). An illuminating device for a microlithography projection-exposure system as set forth in claim 1, wherein an objective lens (2) having a light source (1) and a glass rod (5) and a cime axicon (24) is arranged. 3. The device according to claim 2, comprising two axicones (22, 23), and by adjusting the distance between the two axicons (22, 23), the annular structure name or multipole illumination of conventional illumination and various geometric shapes A luminaire for microlithographic projection-exposure installations, characterized by being configurable. A symmetrical arrangement according to claim 1, wherein between the light source 1 'and the glass rod 7' a conventional illumination with adjustable coherence coefficient σ, an annular structure name, and two or four directions of symmetry. There is provided an apparatus for selectively processing various illumination methods including inclined lighting, the apparatus comprising means for separating and collecting the beams emitted from the light source 1 'into two or four solid angle regions 21'-24'. Beams for sectors of the pupil plane 93 'which are converted into reticle planes for the reticle 10'to be imaged, and means 31'-34' for forming or shading the collected beams. Reflectors (511'-514 ', 521'-524', 531 ', 533'; 6 ') and images of the beams are radially and azimuthal in the pupil plane 93' Microlithographic projection comprising an adjustment means 541'-544'to be movable Gwangseol cost of the illumination device. 5. A microlithography projection-exposure system as set forth in claim 4, wherein said collecting means (21'-24 ') or said collecting or forming means of said luminous flux comprises photoconductors (31'-34'). Lighting equipment. 6. An apparatus according to claim 5, wherein said adjusting means (541'-544 ') adjusts the positions of the outlets of said light conductors (31'-34'). 5. A lighting device for a microlithography projection-exposure system as set forth in claim 4, wherein said adjusting means (541'-544 ') controls the members of said reflecting mechanism (511'-533'). 8. Microlithography projection according to any one of claims 4 to 7, wherein the image of the beams in the pupil plane 93 'is dimensioned to be suitable for symmetrical oblique or conventional illumination. Lighting equipment for exposure equipment. 8. An illuminating device according to any one of claims 4 to 7, wherein means for changing the image size of the beams is provided in the pupil plane. 8. A lighting apparatus for a microlithography projection exposure apparatus according to any one of claims 4 to 7, wherein means for changing the image shape of the beams is provided. 8. A lighting device for a microlithography projection-exposure system according to any one of claims 4 to 7, wherein the beams appear in the shape of an annular segment. 8. An illuminating device according to any one of the preceding claims, wherein said light source is a laser. The method according to claim 1, 2 or 3, Two axicones 22, 23 are provided, the two axicons 22, 23 are directly contiguous with each other in the beam path and their spacing is adjustable, and one axicon 22 is concave. And the second axicon (23) is convex, and the attachment of the two axicons (22, 23) is in the same direction. 14. A lighting apparatus for a microlithography projection-exposure system as set forth in claim 13 wherein said axicons (22, 23) have the same sharpness [alpha] that can be made manufacturable and functionally useful. 14. An illuminating device according to claim 13, wherein the spacing of said axicons (22, 23) can be reduced until contact. 15. A lighting device according to claim 13, wherein the axicons (22, 23) are conical. 15. A lighting device according to claim 13, wherein the axicons (22, 23) are pyramid shaped. 8. Apparatus as claimed in any one of the preceding claims, comprising an objective lens (2) having a zoom function. 8. A light source (1) according to any one of the preceding claims, comprising a light source (1) in focus of the lamp reflector, A shutter (13) for forming a second light source is disposed outside the focus (121) of the lamp reflector (12). 8. A lighting apparatus according to any one of the preceding claims, wherein said reticle masking system (51) comprises a diaphragm plate that is inclined.