TW202020570A - Illumination optical system exposure apparatus and method of manufacturing article - Google Patents

Abstract

The present invention relates to a lighting optical system which is advantageous because of lighting with high uniformity, and is available in various sizes. The lighting optical system is used in an exposure apparatus which projects a pattern of an original plate onto a substrate, and is configured to light the original plate using the light from a light source. The lighting optical system comprises: a first reflective optical integrator; and a second reflective optical integrator, wherein the second reflective optical integrator has a hollow structure, and a portion of the first reflective optical integrator is disposed in the second reflective optical integrator.

Description

Illumination optical system, exposure device and article manufacturing method

The invention relates to an illumination optical system, an exposure device, and an article manufacturing method.

An exposure device can be used for a lithography process for manufacturing articles such as semiconductor devices. The exposure device includes an illumination optical system that illuminates the main board, and a projection optical system that projects the pattern of the illuminated main board onto the substrate. The substrate has a photoresist on the surface, and the pattern of the main board is projected on the substrate so that the pattern is transferred to the photoresist. When the illumination through the main board of the illumination optical system is uneven, the pattern transfer to the photoresist may not be performed well. Therefore, a reflective optical integrator for illuminating the main board with uniform illuminance can be arranged in the illumination optical system.

To improve the uniformity of illuminance, although a reflective optical integrator with a long full length is advantageous, it is difficult to manufacture a reflective optical integrator with a long full length at low cost. Patent Document 1 has described a configuration in which a light rod (glass rod) is used as a reflective optical integrator, and a plurality of light rods are arranged in series in the passing direction of illumination light. With this configuration, the same effect as the case of using one optical integrator having a total length of a plurality of optical integrators is obtained.

In addition, in recent years, in order to reduce the manufacturing cost of semiconductor devices, the substrate size has been increased. For example, in panel-level packaging technology (FOPLP), many silicon dies are carried on a large substrate and the manufacturing of the package is implemented collectively, so as to reduce the manufacturing cost of each package. On the other hand, general wafer-sized substrates are still used. Therefore, there are exposure devices of various sizes corresponding to the size of the substrate to be processed. For this reason, depending on the size of the substrate to be handled, the total length of the illumination optical system such as the distance between the light source and the main board also varies. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2005-32909

[Problems to be solved by the invention]

To simply realize the illumination optical system with various full lengths, consider the method of changing the number of plural rods arranged in series. However, in this method, a gap is generated between adjacent optical integrators. This gap causes an increase in light propagation loss and a decrease in lighting efficiency. To illuminate the illuminated area with higher uniformity, although it is preferable to increase the incident angle of the illuminating light relative to the incident surface of the optical integrator, but in the slight gap between adjacent optical integrators, the light propagates The loss may increase. To make the gap disappear, a technique called optical contact is used to make the end faces of adjacent optical integrators closely contact each other. However, the long optical integrator formed by this technique is weak against physical and thermal external forces, so it is difficult to apply in terms of stability.

An object of the present invention is to provide an illumination optical system, which is advantageous for illuminating an illuminated area with high illuminance and high uniformity, and can cope with various sizes. [Technical means to solve problems]

One aspect of the present invention relates to an illumination optical system that is an exposure device for projecting a pattern of a main board onto a substrate. The illumination optical system is configured to illuminate the main board using light from a light source. The illumination optics The system includes a first reflective optical integrator and a second reflective optical integrator, the second reflective optical integrator has a hollow structure, and a portion of the first reflective optical integrator is disposed in the second reflective optical integrator Among. [Comparing the efficacy of the previous technology]

According to the present invention, an illumination optical system is provided, which is advantageous for illuminating an illuminated area with high illuminance and high uniformity, and can cope with various sizes.

Hereinafter, the present invention will be described with reference to the drawings, through its exemplary embodiments.

FIGS. 1 and 2 schematically show the configuration of the exposure apparatus 100 or the illumination optical system 101 according to the first embodiment of the present invention. In Fig. 1, Fig. 2 and Fig. 3 referred to later, the directions are displayed in the XYZ coordinate system. The exposure apparatus 100 can be used in a lithography process for manufacturing articles such as semiconductor devices. The exposure apparatus 100 may include an illumination optical system 101 that illuminates the motherboard R, a projection optical system 103 that projects the pattern of the motherboard R on the substrate W, a motherboard drive mechanism 102 that holds and drives the motherboard R, and holds and drives the substrate W的板驱动机构104。 The substrate drive mechanism 104. The exposure device 100 may be configured as a repeating step type or as a step-scan type. In the exposure device 100 or the illumination optical system 101, the optical axis AX can be bent through the mirror. The bending of the optical axis AX facilitates the miniaturization of the exposure apparatus 100 or the illumination optical system 101. In one example, the optical axis AX may include a portion parallel to the Z axis (between the light source 1 and the mirror M1, and between the mirror M2 and the substrate W), and a portion parallel to the Y axis (the mirror M1 and the mirror M2 between).

In order to suppress the reduction in vibration suppression performance due to the increased weight of the illumination optical system 101, the illumination optical system 101 is separated into the first illumination optical system 10 and the second illumination optical system 20, and the first illumination optical system 10 and the second illumination optical system 20 It can be supported by independent support mechanisms. The first illumination optical system 10 can be supported via a first support mechanism (not shown) supported through the bottom structure. The second illumination optical system 20 can be supported together with the main board drive mechanism 102 and the projection optical system 103 via a not-shown flat plate supported by the bottom structure via a second support mechanism not shown.

The illumination optical system 101 adjusts the light (light beam) from the light source 1 and illuminates the main board R disposed in the illuminated area (object surface of the projection optical system 103). The light source 1 may be, for example, an ultra-high pressure mercury lamp that generates light such as i-rays (wavelength 365 nm). Alternatively, the light source 1 may be a KrF excimer laser that generates light with a wavelength of 248 nm, an ArF excimer laser that generates light with a wavelength of 193 nm, or an F ₂ laser that generates light with a wavelength of 157 nm, but is not limited thereto. Examples from places.

The main board R has a pattern (for example, a circuit pattern) to be transferred to the substrate W. The main board R may be made of quartz glass as a base material, for example. The motherboard drive mechanism 102 may include, for example, a movable motherboard table that holds the motherboard R, and a motherboard drive mechanism that drives the motherboard table on the X axis and the Z axis. The projection optical system 103 projects the light passing through the main board R on the substrate W at a predetermined magnification (for example, 1/2 times). The substrate W may be arranged on the image plane of the projection optical system 103. The substrate W has a photoresist (photosensitive material) on the surface. The substrate driving mechanism 104 may include a movable substrate stage that holds the substrate W, and X, Y, and Z axes of the substrate table (and sometimes ωx, ωy in the respective rotation directions of these) , Ωz) to drive the substrate drive mechanism.

Hereinafter, the illumination optical system 101 will be described. The illumination optical system 101 may include, for example, a light source 1, an elliptical mirror 2, a relay lens 3, a bending mirror M1, an optical integrator 4, a bending mirror M2, and a focusing lens 5. The first illumination optical system 10 may include, for example, a light source 1, an elliptical mirror 2, a relay lens 3, a bending mirror M1, and an optical integrator 4. The second illumination optical system 20 may include, for example, a bending mirror M2 and a focusing lens 5.

In the first illumination optical system 10, the elliptical mirror 2, the relay lens 3, the bending mirror M1, and the optical integrator 4 may be arranged in this order from the side of the light source 1. The light beam homogenized by the optical integrator 4 can enter the second illumination optical system 20. The second illumination optical system 20 may include a focusing lens 5 and a bending mirror M2. The elliptical mirror (condenser lens) 2 has a first focus and a second focus, and focuses light emitted from the light source 1 disposed at the first focus at the second focus. The relay lens 3 is an imaging optical system, and its front focal point is arranged at the second focal point of the elliptical mirror 2, and its rear focal point is arranged at the incident surface of the optical integrator 4. In other words, the relay lens 3 has a conjugate relationship between the second focal point of the elliptical mirror 2 and the incident surface of the optical integrator 4. In the vicinity of the pupil plane of the relay lens 3, a wavelength filter that blocks light in a specific wavelength band is arranged, and through this wavelength filter, an exposure wavelength (wavelength of light that exposes the substrate W) can be defined.

The optical integrator 4 is a reflective optical integrator having an incident surface, a reflective surface, and an exit surface ES, and reflects the light beam incident on the incident surface through the reflective surface to be reflected a plurality of times, forming a uniform light intensity distribution on the exit surface ES (Illumination distribution). Although the optical integrator 4 may have a rectangular shape in cross section parallel to the plane (XZ plane) orthogonal to its axis direction LD (direction parallel to the Y axis (longitudinal direction of the optical integrator 4)), it may also have Other shapes (eg polygonal).

The second illumination optical system 20 illuminates the main board R using the light emitted from the exit surface ES of the optical integrator 4. The second illumination optical system 20 includes a focus lens 5, the front focus of the focus lens 5 is arranged on the exit surface ES of the optical integrator 4, and the rear focus of the focus lens 5 is arranged at a position (illuminated area) where the main board R is arranged. In other words, the focusing lens 5 has a conjugate relationship between the exit surface ES of the optical integrator 4 and the surface on which the main board R is disposed. As described above, the first illumination optical system 10 and the second illumination optical system 20 can be supported by independent support mechanisms. With such a configuration, the light intensity distribution (illuminance distribution) following the light intensity distribution (illuminance distribution) of the exit surface ES of the optical integrator 4 forming a uniform light intensity distribution (illuminance distribution) is formed on the main board through the focusing lens 5 R's configuration surface. Therefore, even if the first illumination optical system 10 vibrates due to the driving of the motherboard R through the motherboard driving mechanism 102 and the driving of the substrate W through the substrate driving mechanism 104, the arrangement surface of the motherboard R continues to be illuminated with uniform illuminance. Although the shape of the illuminated area (illuminated area) through the illumination optical system 101 may conform to the shape of the exit surface ES of the optical integrator 4, it is also possible to define the shape of the illuminated area through a light-shielding sheet (not shown).

Hereinafter, the configuration of the optical integrator 4 will be exemplarily described. The optical integrator 4 may include a first reflective optical integrator 4a and a second reflective optical integrator 4b. In the example of FIGS. 1 and 2, the first reflective optical integrator 4 a is arranged between the light source 1 and the second reflective optical integrator 4 b. The exit surface of the second reflective optical integrator 4b is the exit surface ES of the optical integrator 4 and is conjugated with the arrangement surface of the main board R.

The first reflective optical integrator 4a may be a light rod with a solid structure. The second reflective optical integrator 4b may be a hollow rod having a hollow structure. For example, the first reflective optical integrator 4a is a light rod having a rectangular column shape, and the second optical integrator 4b may be a hollow rod in which four plate-shaped mirrors are combined so that the inner surface becomes a reflective surface. The cross-sectional size of the second reflective optical integrator 4b surrounded by four plate mirrors (cross-sectional size parallel to the XZ plane) is slightly larger than the cross-sectional size of the first reflective optical integrator 4a (cross-sectional size parallel to the XZ plane) Big. In addition, a part of the first reflective optical integrator 4a is disposed in the second reflective optical integrator 4b. In other aspects, a part of the first reflective optical integrator 4a and a part of the second reflective optical integrator 4b overlap each other in a direction parallel to the optical axis AX (axial direction LD). With this structure, the reflection surfaces of the two reflective optical integrators 4a and 4b have no gap in the direction parallel to the optical axis AX. Therefore, the light emitted from the first reflective optical integrator 4a enters the second reflective optical integrator 4b without propagation loss. When the second reflective optical integrator 4b has a solid structure, when a foreign object adheres to the exit surface of the second reflective optical integrator 4b (the exit surface ES of the optical integrator 4), it may be projected on the illuminated area. On the other hand, when the second reflective optical integrator 4b has a hollow structure, the problem caused by the adhesion of such foreign matter can be solved.

Among the first reflective optical integrator 4a, the length (the length in the axial direction LD) of a portion disposed in the second reflective optical integrator 4b is variable. In other words, the second reflective optical integrator 4b can be relatively moved in the axial direction LD with respect to the first reflective optical integrator 4a. Thereby, the length TL of the optical integrator 4 in the axial direction LD can be made variable. In FIGS. 1 and 2, the length TL of the optical integrator 4 in the axial direction LD is different from each other.

The illumination optical system 101 of the first embodiment is advantageous in order to achieve high illuminance and high uniformity in the illuminated area without light propagation loss between the first reflective optical integrator 4a and the second reflective optical integrator 4b Perform lighting. In addition, in the illumination optical system 101 of the first embodiment, the total length TL of the optical integrator 4 is variable, so it can cope with the exposure apparatus 100 of various sizes. Therefore, the exposure apparatus 100 provided with the illumination optical system 101 is advantageous for achieving the smallest occupied area corresponding to the size of the substrate W to be processed. In contrast to this, it has been determined that the size of the illumination optical system and the area occupied by the exposure device have been determined to be unfavorable in terms of the conventional configuration with no degree of freedom in changing the overall length of the optical integrator.

In the above example, the first reflective optical integrator 4a is arranged between the light source 1 and the second reflective optical integrator 4b. Alternatively, a second reflective optical integrator 4b may be arranged between the light source 1 and the first reflective optical integrator 4a. In the above example, although the first reflective optical integrator 4a has a solid structure, the first reflective optical integrator 4a may have a hollow structure.

Hereinafter, the exposure apparatus 100 and the illumination optical system 101 according to the second embodiment of the present invention will be described with reference to FIG. 3. Matters not mentioned in the second embodiment can follow the first embodiment. The second embodiment is advantageous for an exposure apparatus that handles a larger substrate W. In the second embodiment, the optical integrator 4 includes a first reflective optical integrator 4a, a second reflective optical integrator 4b, and a third reflective optical integrator 4c. When the optical integrator 4 is composed of three reflective optical integrators 4a, 4b, and 4c, it is advantageous to increase the total length TL of the optical integrator 4.

A first reflective optical integrator 4a can be disposed between the light source 1 and the second reflective optical integrator 4b, and a third reflective optical integrator 4c can be disposed between the light source 1 and the first reflective optical integrator 4a . The first reflective optical integrator 4a may be a light rod with a solid structure. The second reflective optical integrator 4b and the third reflective optical integrator 4c may be hollow rods having a hollow structure. For example, the first reflective optical integrator 4a is a light rod having a rectangular column shape. In addition, the second optical integrator 4b and the third optical integrator 4c may be a hollow rod in which four plate mirrors are combined so that the inner surface becomes a reflecting surface. A part (one end side) of the first reflective optical integrator 4a may be disposed in the second reflective optical integrator 4b. The other part (the other end side) of the first reflective optical integrator 4a may be disposed in the third reflective optical integrator 4c.

The relay lens 3 has a conjugate relationship between the second focal point of the elliptical mirror 2 and the incident surface of the optical integrator 4. The focusing lens 5 has a conjugate relationship between the exit surface ES of the optical integrator 4 and the surface on which the main board R is disposed. The second reflective optical integrator 4b has a hollow structure, so that it is possible to avoid such a problem that foreign matter adheres to the emission surface ES and is projected on the illuminated area.

Among the first reflective optical integrator 4a, the length (the length in the axial direction LD) of a portion disposed in the second reflective optical integrator 4b is variable. Similarly, the length (a length in the axial direction LD) of a portion of the third reflective optical integrator 4c disposed in the second reflective optical integrator 4b is variable. Thereby, the length TL of the optical integrator 4 in the axial direction LD can be made variable. The first reflective optical integrator 4a may have a solid structure or may have a hollow structure.

In the following, a method of manufacturing an article using the aforementioned exposure device will be exemplified and explained. The article may be, for example, a semiconductor IC element, a liquid crystal display element, a MEMS element, etc., but may also be other elements. The article is a procedure for exposing a substrate (wafer, glass substrate, etc.) coated with a photosensitive agent by using the aforementioned exposure device, a procedure for developing the substrate (photosensitive agent), and other well-known procedures for developing the developed substrate Processed to be manufactured. Other well-known procedures include etching, resist stripping, cutting, bonding, and packaging. According to this article manufacturing method, articles of higher quality than ever can be manufactured.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various changes and modifications can be made within the scope of the gist thereof.

4: Optical integrator 4a: First reflective optical integrator 4b: First reflective optical integrator 101: Illumination optical system 100: Exposure device

[Fig. 1] A diagram illustrating an exposure device or an illumination optical system according to the first embodiment of the present invention. [FIG. 2] A diagram showing an exposure device or an illumination optical system according to the first embodiment of the present invention. FIG. 3 is a diagram showing an exposure device or an illumination optical system according to the second embodiment of the present invention.

1: light source

2: Elliptical mirror

3: Relay lens

4: Optical integrator

4a: the first reflective optical integrator

4b: 1st reflective optical integrator

5: focusing lens

10: The first illumination optical system

20: Second illumination optical system

100: exposure device

101: Illumination optical system

102: motherboard drive mechanism

103: Projection optical system

104: substrate drive mechanism

AX: optical axis

ES: shot face

LD: axis direction

M1, M2: reflector

R: Motherboard

TL: length

W: substrate

Claims (9)

An illumination optical system is an exposure device for projecting a pattern of a main board onto a substrate. The illumination optical system is configured to illuminate the main board using light from a light source. The illumination optical system includes a first reflective optical system An integrator and a second reflective optical integrator, the second reflective optical integrator has a hollow structure, and a part of the first reflective optical integrator is disposed in the second reflective optical integrator. An illumination optical system as claimed in item 1 of the patent application, wherein the length of the part of the first reflective optical integrator in the axial direction is variable. An illumination optical system as claimed in item 1 of the patent scope, wherein the first reflective optical integrator is arranged between the light source and the second reflective optical integrator. An illumination optical system as claimed in item 1 of the patent scope, wherein the first reflective optical integrator has a solid structure. An illumination optical system as claimed in item 1 of the patent scope, wherein the first reflective optical integrator has a hollow structure. For example, the illumination optical system according to item 1 of the patent scope further includes a third reflective optical integrator, the third reflective optical integrator has a hollow structure, and the other part of the first reflective optical integrator is disposed in the foregoing 3 Among reflective optical integrators. An illumination optical system as claimed in item 1 of the patent scope, wherein the first reflective optical integrator and the second reflective optical integrator constitute a first illumination optical system, and the illumination optical system further includes the first illumination The second illumination optical system independently supported by the optical system, the exit surface of the optical integrator composed of the first reflective optical integrator and the second reflective optical integrator is the exit surface of the first illumination optical system, as described above The second illumination optical system is configured such that the exit surface of the first illumination optical system and the illuminated area are conjugate. An exposure device comprising: an illumination optical system according to any one of claims 1 to 7; and a projection optical system that projects the pattern of the main board illuminated through the illumination optical system onto the substrate. An article manufacturing method, which includes the following procedures: exposure of a substrate using an exposure device as claimed in item 8 of the patent application scope; and development of the aforementioned substrate; wherein, articles are manufactured from the aforementioned substrate.

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