JP2009004631A - Exposure apparatus and device manufacturing method - Google Patents

Abstract

In an immersion exposure apparatus, liquid is prevented from entering the back side of a substrate.
An exposure apparatus projects an original pattern onto a substrate through a projection optical system and a liquid to expose the substrate. The exposure apparatus includes a substrate chuck that holds the substrate. The substrate chuck includes an ejection port 50 that ejects gas toward the outer peripheral portion of the back surface of the substrate 12.
[Selection] Figure 4B

Description

  The present invention relates to an exposure apparatus that projects an original pattern onto a substrate through a projection optical system and a liquid to expose the substrate, and a device manufacturing method that uses the exposure apparatus as part of a process to manufacture a device. .

An immersion exposure apparatus has attracted attention as an exposure apparatus that realizes a high resolving power and a large depth of focus. In an immersion exposure apparatus, a pattern of an original is projected onto a substrate with a liquid interposed between the projection optical system and the substrate. In the immersion exposure apparatus, there are a method in which the entire surface of the substrate is brought into contact with the liquid and a method in which only a part of the surface of the substrate is brought into contact with the liquid.
Japanese Patent Laying-Open No. 2005-5707

  FIG. 8A is a diagram showing a configuration of a substrate chuck used in the immersion exposure apparatus. FIG. 8B is an enlarged view of a portion A in the substrate chuck 20 of FIG. 8A. The substrate chuck 20 has a plurality of convex portions that support the back surface of the substrate 112. The convex portion 21 arranged on the outermost side among the plurality of convex portions is an annular convex portion. The convex part 22 arrange | positioned inside the cyclic | annular convex part 21 is a pin-shaped or cyclic | annular convex part, for example. The substrate chuck 20 is configured as a vacuum chuck, and holds the substrate 112 by reducing the pressure inside the annular convex portion 21 disposed on the outermost side.

  If scratches are formed on the substrate support surface of the annular convex portion 21 arranged on the outermost side or foreign matter is placed on the substrate support surface, a gap may be generated between the back surface of the substrate 112 and the substrate support surface. . As a result, the liquid 116 flows into the back surface of the substrate 112, and problems such as poor holding of the substrate 112 and a decrease in the liquid level of the liquid 116 may occur.

  FIG. 9 is a view showing another configuration of the substrate chuck used in the immersion exposure apparatus. The substrate chuck 30 is configured as an electrostatic chuck, and holds the substrate 112 by applying a voltage to the electrodes 31 and 32. Even in the substrate chuck 30 illustrated in FIG. 9, the inflow of the liquid 116 to the inside of the back surface of the substrate 112 may cause problems such as poor holding of the substrate 112 and a decrease in the liquid level of the liquid 116.

  The present invention has been made with the above problem recognition as an opportunity, and an object thereof is to prevent, for example, liquid from entering the inside of the back surface of the substrate.

  An exposure apparatus according to a first aspect of the present invention is configured as an exposure apparatus that exposes a substrate by projecting an original pattern onto the substrate via a projection optical system and a liquid, and includes a substrate chuck that holds the substrate. The substrate chuck includes an injection port that injects gas toward an outer peripheral portion of the back surface of the substrate.

  An exposure apparatus according to a second aspect of the present invention is configured as an exposure apparatus that exposes a substrate by projecting an original pattern onto the substrate via a projection optical system and a liquid, and includes a substrate chuck that holds the substrate. The substrate chuck has a plurality of convex portions, and the convex portion arranged on the outermost side among the plurality of convex portions is an annular convex portion, and at least the liquid-repellent coating is provided on the annular convex portion. It has been subjected.

  An exposure apparatus according to a third aspect of the present invention is configured as an exposure apparatus that exposes a substrate by projecting an original pattern onto the substrate via a projection optical system and a liquid, and includes a substrate chuck that holds the substrate. The substrate chuck has a plurality of convex portions, and at least a first convex portion arranged on the outermost side of the plurality of convex portions and a second convex portion arranged closest to the first convex portion. The convex portion is an annular convex portion, and at least the first convex portion and the second convex portion are liquid-repellent coated.

  According to the present invention, for example, liquid can be prevented from entering the inside of the back surface of the substrate.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a drawing schematically showing a configuration of an exposure apparatus according to a preferred embodiment of the present invention. FIG. 2 is a view schematically showing the substrate stage mechanism 5 of the exposure apparatus 100 shown in FIG. The exposure apparatus 100 according to a preferred embodiment of the present invention is configured as an immersion exposure apparatus. That is, the exposure apparatus 100 illuminates the original (reticle) held on the original stage 2 by the illumination optical system 1 and projects the pattern of the original onto the substrate 12 via the projection optical system 3 and the liquid. As a result, the substrate 12 is exposed.

  The substrate stage mechanism 5 includes, for example, a substrate stage surface plate 5A, a substrate stage (slider) 5B that moves on the substrate stage surface plate 5A, and a substrate chuck 5C mounted on the substrate stage 5B.

  When the exposure apparatus 100 is configured as a scanning exposure apparatus, the original stage 2 and the substrate stage 5B are scanned and driven at a speed ratio corresponding to the magnification of the projection optical system 3, whereby the substrate 12 can be scanned and exposed.

  The substrate chuck 5C holds the substrate 12. The substrate chuck 5C has a frame 5W so as to form a tank for immersing the entire substrate 12 in the liquid. Details of the substrate chuck 5C will be described later.

  The alignment scope 6 measures an alignment mark formed on the substrate 112 and a reference mark arranged on the substrate stage 5B in order to position the substrate 12. The focus scope 7 measures the height of the surface of the substrate 12, that is, the surface position of the substrate 12 in the optical axis direction of the projection optical system 3 in order to make the surface of the substrate 12 coincide with the image plane of the projection optical system 3. .

  The X bar mirror 8 is used to measure the position of the substrate stage 5B in the X direction with a laser interferometer. The Y bar mirror 9 is used to measure the position of the substrate stage 5B in the Y direction with a laser interferometer. The stage reference mark 10 is provided on the substrate stage 5B and is used for alignment. The illuminance sensor 11 is provided on the substrate stage 5B and is used for measuring the illuminance of exposure light.

  The transport robot 13 is used for transporting the substrate to the substrate chuck 5C and collecting the substrate from the substrate chuck 5C.

  The liquid tank 14 stores liquid for immersion, supplies liquid to the supply / recovery unit 15, and recovers it from the supply / recovery unit 15. The supply / recovery unit 15 supplies the liquid to the substrate 12 and recovers the liquid from the substrate 12.

  Hereinafter, a sequence when the substrate is exposed by the exposure apparatus 100 will be described with reference to FIG. First, as shown in FIG. 3A, alignment measurement and focus measurement are performed on the substrate 12 transferred to the substrate chuck 5C on the substrate stage 5B. In this state, no liquid exists between the substrate 12 and the projection optical system 3. If liquid is present between the substrate 12 and the projection optical system 3 during alignment measurement and focus measurement, the difference in refractive index between the resist on the substrate and the liquid, and the liquid level and the resist. Since the difference in reflectance from the surface is small, it is difficult to measure for focus.

  When the alignment measurement and the focus measurement are completed, the substrate stage 5B (substrate 12) is driven to a position below the supply / recovery unit 15 as shown in FIG. Liquid is supplied. Here, the liquid is supplied into the frame of the substrate chuck 5C so that the substrate 12 is completely immersed. Liquid has a higher refractive index than air and fills the space between the final surface of the projection optical system 3 and the substrate 12 with the liquid, thereby increasing the apparent NA of the projection optical system 3 and improving the resolution. To do.

  Next, as shown in FIG. 3C, the substrate stage 5B is driven to the exposure position while the substrate 12 is immersed in the liquid, and the substrate 12 is exposed as shown in FIG.

  When the exposure is completed, as shown in FIG. 3E, the substrate stage 5 </ b> B is driven to the substrate collection position by the transfer robot 13, and the substrate 12 is collected by the transfer robot 13.

  Next, as shown in FIG. 3F, the substrate 12 is transferred to the outside of the exposure apparatus by the transfer robot 13. Next, as shown in FIG. 3G, the next substrate 12 is transferred to the substrate chuck 5C on the substrate stage 5B by the transfer robot 13. Thereafter, the same processing as described above is performed on the next substrate 12.

  FIG. 4A is a diagram schematically showing the configuration of the substrate chuck 5C of the first embodiment. FIG. 4B is an enlarged view of a portion A in the substrate chuck 5C of FIG. 4A. The substrate chuck 5C shown in FIGS. 4A and 4B has a plurality of convex portions that support the back surface of the substrate 12. The convex portion 21 arranged on the outermost side among the plurality of convex portions is an annular convex portion. The convex part 22 arrange | positioned inside the cyclic | annular convex part 21 is a pin-shaped or cyclic | annular convex part, for example. The substrate chuck 20 is configured as a vacuum chuck, and holds the substrate 12 by reducing the pressure inside the annular convex portion 21 disposed on the outermost side.

  The substrate chuck 5 </ b> C includes an ejection port 50 that ejects gas toward the outer peripheral portion of the back surface of the substrate 12. The injection port 50 is arrange | positioned on the outer side of the cyclic | annular convex part 21 arrange | positioned on the outermost side. The substrate chuck 5 </ b> C can include at least the annular protrusion 21, preferably the annular protrusion 21, and the liquid-repellent coating 19 applied to the outer portion in addition to or instead of the injection opening 50. . The liquid repellent coating 19 preferably has a wetting angle of 90 ° or more, for example. The gas injected from the injection port 50 and / or the liquid repellent coating 19 prevents the liquid from entering the back surface of the substrate 12. The pressure of the gas injected from the injection port 50 is sufficiently smaller than the force for vacuum-adsorbing the substrate 12 so that the peripheral portion of the substrate 12 is not lifted and the flatness of the substrate 12 is not deteriorated. It is preferable to make it. Moreover, it is preferable that the gas injected from the injection port 50 is injected only at the time of exposure so as not to promote the vaporization of the liquid 16. Here, “liquid repellency” means that the liquid is repelled, and when the liquid is water, it is called “water repellency”.

  FIG. 5 is a diagram schematically showing the configuration of the substrate chuck 5C of the second embodiment. The substrate chuck 5 </ b> C is configured as an electrostatic chuck, and holds the substrate 12 by applying a voltage to the electrodes 31 and 32. The substrate chuck 5 </ b> C of the second embodiment includes an ejection port 50 that ejects gas toward the outer peripheral portion of the back surface of the substrate 12. The substrate chuck 5 </ b> C of the second embodiment can include a liquid repellent coating applied to at least a portion facing the outer peripheral portion of the back surface of the substrate 12 in addition to or instead of the injection port 50.

The gas and / or liquid repellent coating sprayed from the spray port 50 prevents the liquid from entering the back surface of the substrate 12.

  FIG. 6A is a diagram schematically showing a configuration of a substrate chuck 5C of the third embodiment. FIG. 6B is an enlarged view of a portion A in the substrate chuck 5C of FIG. 4A. The substrate chuck 5C shown in FIGS. 6A and 6B has a plurality of convex portions. Of the plurality of convex portions, the first convex portion 25 disposed on the outermost side and the second convex portion 21 disposed closest to the first convex portion 25 are annular convex portions. The convex part 22 arrange | positioned inside the 2nd convex part 21 is a pin-shaped or cyclic | annular convex part, for example. The substrate chuck 20 is configured as a vacuum chuck, and holds the substrate 12 by reducing the pressure inside the annular convex portion 21 disposed on the outermost side. In this way, by adding the annular protrusion 25 to the outside of the annular protrusion 21 that defines the decompression space for vacuum suction of the substrate 12, liquid can be prevented from entering the inside of the annular protrusion 21. Is done. Here, the width of the first protrusion 25 can be configured to be narrower than the width of the second protrusion 21.

  The substrate chuck 5 </ b> C preferably includes a first protrusion 25 and a discharge port for discharging a liquid that can accumulate between the first protrusion 25. Such discharge of the liquid can be performed in a state where the substrate 12 is not held.

  As shown in FIG. 6C, the height of the first convex portion 25 may be lower than the height of the second convex portion 21. According to such a configuration, by providing the first convex portion 25, the possibility that the flatness of the substrate 12 is lowered due to the foreign matter sandwiched between the first convex portion 25 and the substrate 12 is reduced. be able to.

  In the configuration example shown in FIGS. 6B and 6C, it is preferable that the liquid repellent coating 19 is applied to at least the first convex portion 25 and the second convex portion 21. Such a liquid repellent coating 19 can more effectively prevent liquid from entering the inside of the back surface of the substrate 12.

  FIG. 6D is a diagram schematically showing the configuration of the substrate chuck 5C of the fourth embodiment. The substrate chuck 5C of the fourth embodiment is configured as an electrostatic chuck. Also in such an electrostatic chuck, as shown in FIG. 6B or FIG. 6C, the electrostatic chuck includes the first convex portion 25 and the second convex portion 21, and at least the first convex portion 25 and the second convex portion 21 include the first convex portion 25 and the second convex portion 21. A configuration to which the liquid repellent coating 19 is applied can be adopted. However, the surface that attracts the substrate is configured to function as an electrostatic chuck.

  FIG. 7A schematically shows the arrangement of an exposure apparatus according to the fifth embodiment of the present invention. FIG. 7B is a view showing a part of the exposure apparatus shown in FIG. 7A in more detail. In the first to fourth embodiments, the present invention is applied to a method in which the entire substrate is immersed in a liquid. In the fifth embodiment, a part of the substrate, more specifically, the exposure light is applied to the substrate. The liquid is selectively brought into contact with only the incident area and its periphery. Such a method is sometimes called a local fill method.

  In the exposure apparatus of the fourth embodiment, liquid is supplied from the supply nozzle 18 to a space between a partial region of the substrate 12 and the final surface of the projection optical system 3, and the liquid is recovered by the liquid recovery nozzle 17. Typically, while the liquid is in contact with the substrate 12, the liquid is continuously supplied from the supply nozzle 18 to the space between the partial region of the substrate 12 and the final surface of the projection optical system 3. Excess liquid is continuously recovered by the liquid recovery nozzle 17.

  Also in such an exposure apparatus, the substrate chuck 5C represented by the first to fourth embodiments described above can be used. In this case, a frame for forming a tank for immersing the entire substrate in the liquid is unnecessary, and instead, it is preferable that the periphery of the substrate is surrounded by the same surface plate having the same height as the surface of the substrate. .

  Next, a device manufacturing method using the above exposure apparatus will be described. FIG. 10 is a diagram showing a flow of an entire manufacturing process of a semiconductor device. In step 1 (circuit design), a semiconductor device circuit is designed. In step 2 (reticle fabrication), a reticle (also referred to as an original or a mask) is fabricated based on the designed circuit pattern. On the other hand, in step 3 (wafer manufacture), a wafer (also referred to as a substrate) is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the reticle and wafer. The next step 5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer produced in step 4, and is an assembly process (dicing, bonding), packaging process (chip encapsulation), etc. Process. In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test. Through these steps, the semiconductor device is completed and shipped (step 7).

  FIG. 11 is a flowchart showing the detailed flow of the wafer process. In step 11 (oxidation), the wafer surface is oxidized. In step 12 (CVD), an insulating film is formed on the wafer surface. In step 13 (electrode formation), an electrode is formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (CMP), the insulating film is planarized by a CMP process. In step 16 (resist process), a photosensitive agent is applied to the wafer. In step 17 (exposure), the above exposure apparatus is used to expose a wafer coated with a photosensitive agent through a mask on which a circuit pattern is formed, thereby forming a latent image pattern on the resist. In step 18 (development), the latent image pattern formed on the resist on the wafer is developed to form a resist pattern. In step 19 (etching), the layer or substrate under the resist pattern is etched through the portion where the resist pattern is opened. In step 20 (resist stripping), the resist that has become unnecessary after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

It is a figure which shows schematically the structure of the exposure apparatus of suitable embodiment of this invention. FIG. 2 is a view schematically showing a substrate stage mechanism of the exposure apparatus shown in FIG. 1 and its periphery. A sequence when the substrate is exposed by the exposure apparatus shown in FIG. 1 will be described. It is a figure which shows typically the structure of the substrate chuck of 1st Embodiment. It is a figure which shows typically the structure of the substrate chuck of 1st Embodiment. It is a figure which shows typically the structure of the substrate chuck of 2nd Embodiment. It is a figure which shows typically the structure of the substrate chuck of 3rd Embodiment. It is a figure which shows typically the structure of the substrate chuck of 3rd and 4th embodiment. It is a figure which shows typically the structure of the substrate chuck of 3rd and 4th embodiment. It is a figure which shows typically the structure of the substrate chuck of 4th Embodiment. It is a figure which shows schematically the structure of the exposure apparatus of 5th Embodiment of this invention. It is a figure which shows schematically the structure of the exposure apparatus of 5th Embodiment of this invention. It is a figure which shows the structure of the substrate chuck used in an immersion exposure apparatus. It is the figure which expanded the A section in the substrate chuck | zipper of FIG. 8A. It is a figure which shows the other structure of the substrate chuck used in an immersion exposure apparatus. It is a figure which shows the flow of the whole manufacturing process of a semiconductor device. It is a figure which shows the detailed flow of a wafer process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Illumination system unit 2 Original stage 3 Projection optical system 5 Exposure stage mechanism 5A Substrate stage surface plate 5B Substrate stage (slider)
5C Substrate chuck 6 Alignment scope 7 Focus scope 8 X bar mirror 9 Y bar mirror 10 Reference mark 11 Illuminance sensor 12 Substrate 13 Transfer robot 14 Liquid tank 15 Supply recovery unit 16 Liquid 17 Recovery nozzle 18 Supply nozzle 19 Liquid repellent coating 21 Protrusion 22 Convex Part 23 Convex part 31, 32 Electrode 50 Injection port

Claims (9)

An exposure apparatus that exposes a substrate by projecting an original pattern onto the substrate via a projection optical system and a liquid,
A substrate chuck for holding the substrate;
The substrate chuck includes an injection port for injecting gas toward the outer peripheral portion of the back surface of the substrate.
An exposure apparatus characterized by that.   The substrate chuck has a plurality of convex portions that support the back surface of the substrate, the convex portion arranged on the outermost side among the plurality of convex portions is an annular convex portion, and the injection port is the annular annular portion. The exposure apparatus according to claim 1, wherein the exposure apparatus is disposed outside the convex portion.   The exposure apparatus according to claim 2, wherein a liquid repellent coating is applied to at least the annular convex portion. An exposure apparatus that exposes a substrate by projecting an original pattern onto the substrate via a projection optical system and a liquid,
A substrate chuck for holding the substrate;
The substrate chuck has a plurality of convex portions, and the convex portion arranged on the outermost side among the plurality of convex portions is an annular convex portion, and at least the liquid-repellent coating is provided on the annular convex portion. It has been subjected,
An exposure apparatus characterized by that. An exposure apparatus that exposes a substrate by projecting an original pattern onto the substrate via a projection optical system and a liquid,
A substrate chuck for holding the substrate;
The substrate chuck has a plurality of convex portions, and at least a first convex portion arranged on the outermost side of the plurality of convex portions and a second convex portion arranged closest to the first convex portion. The convex part is an annular convex part,
Liquid repellent coating is applied to at least the first and second protrusions,
An exposure apparatus characterized by that.   6. The exposure apparatus according to claim 5, wherein a height of the first convex portion is lower than a height of the second convex portion, and the first convex portion does not contact the substrate.   7. The exposure apparatus according to claim 5, wherein a width of the first convex portion is narrower than a width of the second convex portion.   The exposure apparatus according to claim 5, wherein the substrate is held by the substrate chuck by reducing the pressure inside the second convex portion. A device manufacturing method comprising:
A step of exposing the substrate using the exposure apparatus according to claim 1;
Developing the substrate;
A device manufacturing method comprising:

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