JP2019215418A - Substrate holding device, exposure equipment, and manufacturing method of article - Google Patents

Abstract

To provide a substrate holding device and exposure equipment, capable of reducing exposure unevenness.SOLUTION: In a substrate holding device including a base holding a substrate and having a clearance, and a light source mechanism provided on the clearance, for radiating light toward the substrate, a quantity of light radiated from the light source mechanism toward the substrate is adjusted so that a difference is reduced, between a quantity of light reflected by the base, and arriving at a first resist area over the base, and a quantity of light emitted from the light source mechanism, and arriving at a second resist area over the light source mechanism.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a substrate holding device, an exposure device, and an article manufacturing method.

  When manufacturing a device such as a semiconductor device or a liquid crystal display device using a photolithography technique, an exposure apparatus that transfers a pattern by projecting a mask pattern onto a substrate by a projection optical system is used.

  The device manufacturing process includes a process of applying a resist to the substrate, a process of transferring a pattern to the substrate by exposure, and a process of developing the substrate to which the pattern has been transferred. Generally, a step of applying a resist to a substrate and a step of developing a substrate on which a pattern has been transferred are performed by a coater / developer different from an exposure apparatus that transfers a pattern to a substrate by exposure.

  As described above, in the device manufacturing process, the device is manufactured while transferring the substrate between different apparatuses. Each device is provided with a substrate holding mechanism for holding the substrate by suction or the like and transferring the substrate. The substrate holding mechanism includes a base for holding the substrate and a substrate lift such as a lift pin for raising and lowering the substrate. It is common to include a mechanism.

  Here, a gap is formed between the base provided below the substrate and the substrate lifting mechanism. Therefore, the substrate has a region where the base and the substrate elevating mechanism are disposed below the substrate, and a region where these are not disposed.

  In recent years, it has also become common to manufacture devices using a transparent substrate through which exposure light is transmitted.When performing exposure on a transparent substrate, the exposure light transmitted through the substrate moves up and down the base and the substrate. The light is reflected by the mechanism, and the reflected light exposes the resist applied on the substrate. When the resist is exposed to light by this reflected light, exposure unevenness occurs on the substrate.

  As a method for reducing the above-mentioned exposure unevenness, Patent Document 1 discloses a configuration in which reflection of exposure light is limited by providing an antireflection member in a gap below a substrate. Japanese Patent Application Laid-Open No. H11-163873 has an object that exposure light incident on a gap below a substrate exposes a resist on the substrate as reflected light, and the amount of exposure becomes excessive in a region on the substrate located above the gap. In order to reduce the amount of exposure in a region on the substrate located above the gap, an anti-reflection member is arranged in the gap in the substrate holding device in Patent Document 1.

Chinese Patent Application Publication No. 1050404848

  On the other hand, the inventor of the present application has found that the exposure light incident on the gap under the substrate advances to the lower portion of the substrate holding device and is attenuated, and most of the light does not reach the resist on the substrate. Accordingly, an object of the present invention is to reduce the above-described exposure unevenness by irradiating light to a resist above the gap.

  A substrate holding device of the present invention that solves the above-mentioned problem is a substrate holding device that holds a substrate, includes a base having a gap, and a light source mechanism that is provided in the gap and irradiates light to the substrate. A resist is applied on the substrate, and the amount of light reflected by the base and reaching the first resist region on the base, and emitted from the light source mechanism, The amount of light emitted from the light source mechanism to the substrate is adjusted so that the difference between the amount of light reaching the two resist regions is reduced.

  According to the present invention, a substrate holding device and an exposure device capable of reducing exposure unevenness are obtained.

It is a schematic diagram of an exposure apparatus. It is a schematic diagram of a substrate holding mechanism. FIG. 4 is a view showing a first embodiment of a base constituting the substrate holding mechanism. It is a figure showing a 2nd example of a base which constitutes a substrate holding mechanism. It is a figure showing a 3rd example of a base which constitutes a substrate holding mechanism. It is the schematic which shows the generation | occurrence | production mechanism of exposure unevenness. FIG. 4 is a diagram illustrating a relationship between a wavelength of light and a transmittance in a photosensitive agent. FIG. 3 is a diagram illustrating a configuration for reducing exposure unevenness. It is the schematic which shows the arrangement | sequence of a light source. FIG. 3 is a diagram illustrating a first configuration example of a light source mechanism. It is a figure showing the 2nd example of composition of a light source mechanism. It is a figure showing the 3rd example of composition of a light source mechanism.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The substrate holding device of the present invention is suitable for holding a transparent substrate such as a sapphire substrate or a glass substrate. The sapphire substrate is used as a substrate for an LED (Light Emitting Diode) element or the like. A glass substrate is used as a substrate for a liquid crystal panel or the like.

  FIG. 1 is a schematic diagram illustrating a configuration of an exposure apparatus 1 according to one aspect of the present embodiment. The exposure apparatus 1 is used for forming a pattern on a substrate. The exposure apparatus 1 includes a light source device 100 including an exposure light source 110, an illumination optical system 200 for illuminating the original 310, and an original stage 300 for holding the original 310. Further, the exposure apparatus 1 includes a projection optical system 400 that projects an image of the pattern of the original 310 onto a substrate 510 held on a substrate stage 500 (substrate holding device).

  As the light source 110, a high-pressure mercury lamp, an excimer laser, or the like is used. As general exposure light, g-ray (wavelength: about 436 nm) or near-ultraviolet light having a wavelength range of 100 nm to 400 nm is used. For example, g-line or i-line (wavelength: about 365 nm) of an ultra-high pressure mercury lamp, KrF excimer laser light (wavelength: about 248 nm), ArF excimer laser light (wavelength: about 193 nm), F2 laser light (wavelength: about 157 nm), and the like are used. .

  Light emitted from the light source 110 is guided to the original 310 via the optical system 210 included in the illumination optical system 200. The projection optical system 400 includes an optical system 410 and an aperture stop 420, and projects the pattern of the original 310 onto the substrate 510 at a predetermined projection magnification. A photosensitive agent (resist) having sensitivity to light of a specific wavelength is applied to the substrate 510, and when an image of the pattern of the original 310 is projected on the resist, a latent image pattern is formed on the resist.

  The substrate 510 is held by a substrate holding mechanism 500 as a substrate holding device. The substrate holding mechanism 500 holds the substrate 510 by vacuum suction or electrostatic suction using a suction pad (not shown). The detailed configuration of the substrate holding mechanism 500 will be described later.

  In this embodiment, the exposure apparatus 1 is a scanning exposure apparatus (scanner) that transfers the pattern of the original 310 to the substrate 510 while scanning the original 310 and the substrate 510 synchronously with each other in the scanning direction. Hereinafter, the vertical direction is the Z-axis direction, the scanning direction of the substrate 510 in a plane perpendicular to the Z-axis direction is the Y-axis direction, and the non-scanning direction that is the direction perpendicular to the Z-axis direction and the Y-axis direction is the X-axis direction. I do.

  The amount of light (exposure amount) projected onto the substrate 510 by the projection optical system 400 is an important factor for determining the line width of the pattern, and by exposing the resist on the substrate 510 with an appropriate exposure amount, the accuracy can be improved. A high pattern can be formed.

  For example, in the case where the same pattern is repeatedly formed in the pattern formation region on the substrate 510, it is preferable to perform exposure so that exposure unevenness does not occur in the entire pattern formation region. By devising the configuration of the illumination optical system 200 and the projection optical system 400, it is possible to reduce unevenness in the amount of exposure projected on the substrate 510, but so-called flare light is applied to the resist on the substrate 510. This may cause unevenness in the amount of light incident on the resist.

  Here, of the light transmitted through the original plate 310, the light transmitted through the optical system 410 included in the projection optical system 400 and the opening of the aperture stop 420 and irradiated on the resist on the substrate 510 is assumed to be regular light. Light other than regular light is flare light.

(About the occurrence of exposure unevenness)
Next, the cause of the occurrence of exposure unevenness in the exposure apparatus will be described with reference to FIGS. FIG. 2A shows a state where the substrate 510 is held by the substrate holding mechanism 500. FIG. 2B shows a state where the substrate 510 is lifted in the Z-axis direction by the substrate lifting mechanism 522. The substrate 510 is transported by a substrate transport device such as a transport robot (not shown) while being separated from the substrate holding mechanism 500 by the substrate lifting mechanism 522.

  2A, the substrate holding mechanism 500 vacuum-adsorbs the substrate 510 using a suction pad (not shown) located between the base 521 and the substrate 510. The suction pad is provided on the upper surface of the base 521. Note that the method of holding the substrate 510 is not limited to vacuum suction, and may be a configuration in which the substrate 510 is held by, for example, electrostatic suction. When exposure is performed on the substrate 510, the substrate 510 is held by the base 521 as shown in FIG.

  The substrate lifting mechanism 522 is movable in the Z-axis direction, and when the substrate 510 is separated from the base 521, the substrate lifting mechanism 522 moves in the Z-axis direction as shown in FIG. Is lifted upward in the Z-axis direction.

  The substrate lifting mechanism 522 includes a lifting unit 522B that moves up and down in the Z-axis direction and a contact unit 522C that contacts the substrate 510, and the upper surface of the contact unit 522C is defined as an upper surface 522A. Since the contact portion 522C is in contact with the substrate 510, the material of the contact portion 522C is determined in consideration of the fact that the substrate 510 is hardly damaged and the contact portion 522C is hardly worn by contact with the substrate 510. The contact portion 522C is generally made of a resin material or the like.

  Here, as shown in FIG. 2A, when the substrate 510 is held by the base 521, a slight gap is provided between the substrate 510 and the substrate lifting mechanism 522. Accordingly, the risk that the substrate 510 interferes with the substrate lifting / lowering mechanism 522 and the position of the substrate 510 changes in the Z-axis direction can be reduced.

  Next, the positional relationship between the base 521 and the substrate lifting mechanism 522 will be described with reference to FIGS. FIG. 3 shows an example in which a base 521 constituting the substrate holding mechanism 500 is divided into a plurality of (eight) substrate holding units on the XY plane, and a gap is provided between each substrate holding unit. Substrate holders 521a, b, c, and d are arranged on the plus side in the Y-axis direction, and substrate elevating units 522a, b, and c are provided in gaps therebetween. Further, substrate holding parts 521e, f, g, and h are arranged on the minus side in the Y-axis direction, and substrate elevating parts 522d, e, and f are provided in gaps between them. FIG. 3 shows an example in which a lift bar is arranged as a substrate elevating unit.

  In FIG. 4, the base 521 is divided into substrate holders 521a ', b', c ', and d'. Each of the substrate holding units is provided with a substrate elevating unit 522a ', b', c ', d'. A substrate elevating unit 522e 'is provided in a gap between the substrate holding units 521a' and 521b ', and a substrate elevating unit 522f' is provided in a gap between the substrate holding units 521c 'and 521d'. Each substrate lifting unit in FIG. 4 is constituted by a lift bar.

  In FIG. 5, the base 521 is divided into substrate holding parts 521a '', b '', c '', d '', e '', and f ''. Each substrate holding portion is provided with a through-hole, and a lift pin 522 as a substrate lifting mechanism that moves in the Z-axis direction inside the through-hole is provided.

  As described above, the substrate lifting mechanism 522 may be of the lift bar type shown in FIGS. 3 and 4, or may be of the lift pin type shown in FIG. In any case, the substrate lifting / lowering unit constituting the substrate lifting / lowering mechanism 522 is arranged in a gap provided on the base 521. As described with reference to FIGS. 3 to 5, gaps are provided between the substrate holding units and between the substrate holding unit and the substrate elevating unit. Is a factor.

  Next, a mechanism of causing exposure unevenness will be described with reference to FIG. FIG. 6 shows a state in which exposure light is applied to the resist 511 applied on the substrate 510. The light beam 10 incident on the resist 511 from the space above the base 521 passes through the resist 511 and the substrate 510, and is reflected on the upper surface 521A of the base 521. The light beam 12 incident on the resist 511 from the space above the substrate elevating mechanism 522 passes through the resist 511 and the substrate 510 and is reflected by the upper part of the substrate elevating mechanism 522. On the other hand, the light beam 11 incident on the resist 511 from above the gap between the base 521 and the substrate lifting mechanism 522 passes through the resist 511 and the substrate 510.

  Here, part of the exposure light that has entered the resist 511 is absorbed by the resist 511. Depending on the wavelength of the exposure light and the optical characteristics of the resist 511, the light absorption and transmittance differ. The transmittance of the exposure light to the resist is determined as follows.

  First, assuming that the light is a one-dimensional plane wave that propagates in the Z direction, the amplitude E (Z, t) of the plane wave at time t is

It is expressed. k is a wave number and ω is a frequency. Using the complex refractive index N, the frequency ω is

And the amplitude E (Z, t) can be expressed as follows.

  Furthermore, from ω = 2πc / λ

It becomes.

  Further, since the light energy I (Z, t) is obtained from the norm of the square of the amplitude E (Z, t) or the square of the norm of the amplitude E (Z, t),

It is expressed.

  From this, when calculating the light transmittance T,

It becomes.

  The light beam transmitted through the resist 511 according to the transmittance T calculated in this way passes through the substrate 510 and reaches the base 521 and the upper part of the substrate lifting mechanism 522. FIG. 7 is a diagram illustrating the relationship between the wavelength of light and the transmittance of a specific resist. In an exposure apparatus using a mercury lamp, i-ray (wavelength: about 365 nm), h-ray (wavelength: about 405 nm), g-ray (wavelength: about 436 nm), and the like are used as exposure light. In FIG. 7, the transmittance for the i-line is denoted by Ti, the transmittance for the h-line is denoted by Th, and the transmittance for the g-line is denoted by Tg. It can be seen that the transmittance value differs for each wavelength.

  The light that has reached the upper part of the base 521 and the substrate lifting mechanism 522 is reflected on the reflection surface by specular reflection and diffuse reflection. Specular reflection is reflection in which the angle of reflection is determined by the angle of light incident on the reflecting surface, and generally, the angle of incidence of light is equal to the angle of reflection. Diffuse reflection is reflection that does not depend on the angle of incidence of light incident on a reflecting surface, and the intensity of light reflected at an angle θ from a perpendicular to the reflecting surface depends on cos θ. Diffuse reflection is also called Lambert reflection.

  The light specularly or diffusely reflected on the upper surface of the base 521 or the substrate elevating mechanism 522 can enter the resist 511 as flare light after transmitting through the substrate 510. On the other hand, the light shown as the light ray 11 in FIG. 6 enters the gap between the base 521 and the substrate elevating mechanism 522, and most of the light attenuates without reentering the resist 511.

  As described above, a region where much flare light is generated and a region where almost no flare light is generated are formed on the substrate 510. As described above, the flare light is generated according to the reflection characteristics of the upper surface of the base 521 and the substrate elevating mechanism 522, and it is difficult to sufficiently reduce the flare light. Since the amount of flare light incident on the resist 511 differs for each region on the substrate 510, exposure unevenness occurs as a result.

(About the method of reducing exposure unevenness)
Next, a method for reducing exposure unevenness will be described with reference to FIG. In FIG. 8, the above-described exposure unevenness is reduced by providing a light source mechanism O in a gap between the base 521 and the substrate lifting / lowering mechanism 522. The configuration other than the light source mechanism O in FIG. 8 is the same as the configuration shown in FIG.

  Although a detailed configuration of the light source mechanism O will be described later, the light source mechanism O includes a light source 70 and a diffusion plate 80. Since the resist 511 located above the light source mechanism O is exposed to light emitted from the light source 70, exposure unevenness can be reduced.

  The amount of flare light to be incident on the resist 511 located above the gap between the base 521 and the substrate lifting mechanism 522 controls the amount of light emitted from the light source 70 and the position of the light source mechanism O in the vertical direction. Can be adjusted by doing so. The light emission amount of the light source 70 is adjusted by an adjustment unit (not shown) provided in the exposure apparatus 1. Further, the position of the light source mechanism O is adjusted by a position adjusting mechanism described later.

  As a result, the difference between the amount of light reflected by the base 521 and reaching the first resist area above the base 521 and the amount of light emitted from the light source mechanism O and reaching the second resist area above the light source mechanism O is determined. Becomes smaller. The amount of light reflected by the substrate lifting mechanism 522 and reaching the third resist area above the substrate lifting mechanism 522 and the amount of light emitted from the light source mechanism O and reaching the second resist area above the light source mechanism O are described. The difference becomes smaller.

  By appropriately adjusting the amount of light applied to each resist region, the distribution of the amount of flare light applied to the resist 511 can be made uniform to some extent. The first resist region is a region illustrated as 511A in FIG. 8, the second resist region is a region illustrated as 511B in FIG. 8, and the third resist region is illustrated as 511C in FIG. Area.

(About position adjustment of light source mechanism)
As described above, in order to effectively reduce exposure unevenness, it is preferable to provide a position adjustment mechanism for adjusting the position of the light source mechanism O in the Z-axis direction. The reflectance of the base 521 and the substrate lifting mechanism 522 is determined mainly by the physical property values of the material, but the reflectance may vary depending on a manufacturing error or the like. Also, the reflectance may vary depending on the characteristics of the resist, the wavelength of the exposure light, and the process at the time of exposure. By driving the light source mechanism O in the Z-axis direction, it is possible to reduce exposure unevenness that may occur due to these variations in reflectance.

  As shown in FIG. 8, the light source mechanism O is disposed apart from the base 521 and the substrate elevating mechanism 522. The light source mechanism O includes a light source elevating mechanism 90 that supports the light source 70 and the diffusion plate 80, and the light source elevating mechanism 90 is driven in the Z-axis direction by an actuator (not shown). Changes. The light source elevating mechanism 90 functions as a position adjusting mechanism of the light source 70.

  The base 521 and the light source elevating mechanism 90 are mounted on a top plate 525 on a movable stage (not shown) movable in the X-axis direction and the Y-axis direction. The elevating part 522B constituting the substrate elevating mechanism 522 penetrates the top plate 525, and the elevating part 522B is driven in the Z-axis direction along a guide 526 by an actuator (not shown). The light source elevating mechanism 90 is driven in the Z-axis direction by an actuator (not shown) provided on the top plate 525.

(About the configuration of the light source mechanism)
The detailed configuration of the light source mechanism O will be described with reference to FIGS. FIG. 9 shows an arrangement of the light sources 70 included in the light source mechanism O. By arranging a plurality of light sources 70 side by side in the Y-axis direction which is the scanning direction of the exposure apparatus 1, it is possible to effectively reduce exposure unevenness accompanying the scanning exposure.

  FIG. 10 is a diagram illustrating a first configuration example of the light source mechanism O. A plurality of light sources 70 are arranged above a light source elevating mechanism 90, and a diffusion plate 80 is provided above them. As the light source 70 in FIG. 10, an LED, a mercury lamp, or the like that emits light in a wavelength band that exposes the resist 511 is used. Light 71 emitted from each light source 70 is diffused by the diffusion plate 80, and the resist 511 located above the light source mechanism O is exposed by the light 72 transmitted through the diffusion plate 80.

  Here, a filter such as an ND filter or a wavelength filter may be provided on the surface of the diffusion plate 80. By using the ND filter, the amount of light emitted from the light source 70 and incident on the resist 511 located above the light source mechanism O can be appropriately controlled. When a mercury lamp or the like having a wide wavelength band is used as the light source 70, it is preferable to provide a wavelength filter so that light having a wavelength to be incident on the resist 511 can be selected.

  FIG. 11 is a diagram illustrating a second configuration example of the light source mechanism O. As compared with the first configuration example shown in FIG. 10, the second configuration example is different from the first configuration example in the configuration for guiding light from the light source 70 to the diffusion plate 80. In the second configuration example, the light from the light source 70 is guided by the fiber bundle 73 and guided to the diffusion plate 80. By using the fiber bundle 73, the uniformity of the light irradiated on the diffusion plate 80 can be improved.

  FIG. 12 is a diagram illustrating a third configuration example of the light source mechanism O. As compared with the first configuration example shown in FIG. 10, the third configuration example is different from the first configuration example in the configuration for guiding light from the light source 70 to the diffusion plate 80.

  In the third configuration example, the light from the light source 70 is guided using the light guide 74, and the light is emitted from above the light guide 74.

(Modification)
In the above-described embodiment, the embodiment in which the light source mechanism O is disposed in the gap between the base 521 and the substrate elevating mechanism 522 has been described. However, as shown in FIGS. The light source mechanism O may be arranged in the gap between the two. Even when the substrate lifting mechanism 522 is not disposed between the substrate holding units, the same problem as described above may occur if a gap is generated between the substrate holding units. It is.

  Although the example in which the substrate holding device is applied to the scanner as the exposure device 1 has been described above, the present invention is also applicable to, for example, a stepper that fixes the original 310 and projects the pattern of the original 310 onto the substrate 510. The substrate holding device of the present invention is applicable. Further, the substrate holding device of the present invention can be applied to an imprint apparatus that forms a pattern on a substrate by curing the resin with curing light in a state where a mold as an original is pressed against an uncured resin. .

(Production method)
Next, a method for manufacturing an article (semiconductor integrated circuit device, liquid crystal display device, etc.) using the above-described exposure apparatus will be described. As a method of manufacturing an article, a step of irradiating exposure light to a substrate held by using the substrate holding apparatus according to the present invention to form a pattern, and processing (developing, etching, etc.) the pattern-formed substrate ) Is performed. By using the substrate holding device according to the present invention, exposure unevenness can be effectively reduced, and as a result, the accuracy of pattern formation on the substrate can be improved.

  The method of manufacturing the article is advantageous in at least one of performance, quality, productivity, and production cost of the article as compared with the related art. Alternatively, the above-described exposure apparatus can provide articles such as high-quality devices (semiconductor integrated circuit elements, liquid crystal display elements, and the like).

  The preferred embodiments of the present invention have been described above. However, it is needless to say that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

Claims (12)

A base holding a substrate and having a gap,
A substrate holding device that is provided in the gap and includes a light source mechanism that irradiates light toward the substrate,
A resist is applied on the substrate,
The difference between the amount of light reflected by the base and reaching the first resist area above the base and the amount of light emitted from the light source mechanism and reaching the second resist area above the light source mechanism is reduced. As described above, the amount of light emitted from the light source mechanism to the substrate is adjusted.   The substrate holding device according to claim 1, wherein the amount of light emitted from the light source mechanism to the substrate is adjusted by adjusting the amount of light emitted from a light source included in the light source device.   The substrate holding device according to claim 1, wherein the light source mechanism is movable in a vertical direction.   The substrate holding device according to claim 3, further comprising an adjustment mechanism that moves the light source mechanism in a vertical direction.   The substrate holding device according to claim 4, wherein the amount of light emitted from the light source mechanism to the substrate is adjusted by controlling the position of the light source mechanism in the vertical direction using the adjustment mechanism.   The substrate holding device according to claim 1, wherein a through hole is provided in the base, and the light source mechanism is provided inside the through hole. Further comprising an elevating mechanism for vertically elevating the substrate,
The substrate holding device according to any one of claims 1 to 5, wherein the light source mechanism is provided in a gap between the base and the elevating mechanism.   The difference between the amount of light emitted from the light source mechanism and reaching the second resist area above the light source mechanism and the amount of light reflected by the elevating mechanism and reaching the third resist area above the elevating mechanism becomes smaller. 8. The substrate holding apparatus according to claim 7, wherein the amount of light emitted from the light source mechanism to the substrate is adjusted. The base includes a plurality of substrate holding units that hold the substrate,
The substrate holding device according to any one of claims 1 to 8, wherein the light source mechanism is provided in a gap between the plurality of substrate holding units. An exposure apparatus for transferring an original pattern onto a substrate using exposure light,
A pattern of the original is transferred to the transparent substrate while holding a transparent substrate having a property of transmitting exposure light by the substrate holding device according to any one of claims 1 to 9. Exposure equipment.   The exposure apparatus according to claim 10, further comprising an adjustment unit that adjusts a light amount of a light source included in the light source device. A step of exposing a substrate using the exposure apparatus according to claim 10 or 11,
Developing the substrate exposed in the step,
A method for producing an article, comprising:

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