JP4586421B2 - Immersion objective lens and microscope observation device - Google Patents

Description

  The present invention relates to an immersion objective lens and microscope observation apparatus used for immersion observation of an object, and more particularly to an immersion objective lens and microscope observation apparatus suitable for immersion observation of a semiconductor wafer, a liquid crystal substrate, and the like.

In a manufacturing process of a semiconductor circuit element or a liquid crystal display element, a circuit pattern formed on a semiconductor wafer or a liquid crystal substrate (generally referred to as “substrate”) is observed for defects, foreign matters, and the like using a microscope observation apparatus. The microscope observation apparatus is a combination of a mechanism for automatically transporting a substrate and an optical microscope system. The objective lens of the optical microscope system is a dry system, and the gap between the objective lens and the substrate to be observed is filled with a gas such as air (see, for example, Patent Document 1). In order to realize observation with higher resolution, it has been proposed to set the observation wavelength to the ultraviolet region.
JP 2001-118896 A

  By the way, in an apparatus using a dry objective lens, the numerical aperture of the objective lens cannot be made larger than “1”, so that there is a limit to improvement in resolution. Therefore, it is conceivable to use a known immersion method and use an immersion-type objective lens in place of the dry-type objective lens. By using an immersion objective lens and filling the space between the tip and the substrate to be observed with a liquid such as water, the numerical aperture of the objective lens is “1” according to the refractive index (> 1) of the liquid. It can be made larger and the resolution can be improved.

  However, simply exchanging the objective lens from a dry system to an immersion system cannot efficiently observe the substrate in the above manufacturing process. In order to perform the observation efficiently, a mechanism for supplying a liquid between the tip of the immersion objective lens and the substrate and a mechanism for collecting the liquid are required. As such a mechanism, a configuration in which an injection needle-like nozzle member is externally disposed around the objective lens and liquid is supplied / collected via the nozzle member is conceivable. However, if the nozzle member is arranged externally, the structure around the objective lens becomes complicated, and the microscope observation apparatus becomes large. For this reason, it is desirable to devise a liquid supply / recovery mechanism so that the structure around the objective lens is not complicated. In this case, the immersion type objective lens is referred to as an “immersion objective lens”.

  An object of the present invention is to provide an immersion objective lens and a microscope observation apparatus that can arrange a liquid supply / recovery mechanism while simplifying the structure around the objective lens.

The immersion objective lens of the present invention supplies one or more lens elements, a lens barrel that holds the lens elements, and a liquid that penetrates the interior of the lens barrel and supplies liquid to a space near the tip of the lens element. And a recovery liquid channel that is provided independently of the supply liquid channel and collects the liquid in the space, and the opening of the supply liquid channel and the recovery liquid channel is , respectively are provided at a site spatially opposed in the vicinity of the tip, a portion close to the space of the recovery liquid flow path has a thickens shape towards the space.
The total area S1 of the opening of the supply liquid channel and the total area S2 of the opening of the recovery liquid channel may satisfy the relationship of S1 ≦ S2 .

Further, the supply liquid flow path is formed such that a portion on the opening side is inclined with respect to the optical axis of the lens element, and a center line of the portion is more than the focal plane of the lens element or the focal plane. It may be provided so as to intersect the optical axis on a surface away from the lens element .

The microscope observation apparatus of the present invention uses the supporting means for supporting the substrate to be observed, the immersion objective lens of the present invention , and the supply liquid flow path, so that the tip between the lens element tip and the substrate is used. Supply means for supplying liquid to the space and recovery means for recovering the liquid from the space using the recovery liquid flow path .

  According to the present invention, it is possible to arrange the liquid supply / recovery mechanism while simplifying the structure around the objective lens.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
As shown in FIG. 1, the immersion objective lens 10 of the first embodiment includes seven lens elements 11 to 17 arranged along the optical axis 10 a and a lens barrel (20 to 20) that holds the lens elements 11 to 17. 29) and two liquid flow paths 31, 32 provided through the inside of the lens barrel (20-29). The AA cross section of FIG. 1 is shown in FIG. When the immersion objective lens 10 is viewed from below (in the direction of arrow B in FIG. 1), it is as shown in FIG. FIG. 1 is a longitudinal sectional view of the immersion objective lens 10 and corresponds to the CC section of FIG. In describing the structure of the tip portion of the immersion objective lens 10 and the like, FIG. 2B and FIGS. 3A to 3D will be referred to as appropriate. 3A to 3C correspond to the CC cross section of FIG. FIG. 3D corresponds to the DD cross section of FIG.

  The lens barrel (20-29) of the immersion objective lens 10 includes a metal piece 20-27 for fixing the lens elements 11-17 at a predetermined interval, and a cylindrical member 28 configured to cover the outside of the metal piece 20-27. And an annular member 29 attached below the cylindrical member 28. Among these, the cylindrical member 28 and the annular member 29 are fastened with sealing materials 35 and 36 such as O-rings interposed therebetween, thereby preventing liquid leakage from the liquid flow paths 31 and 32 (details will be described later). The lens elements 11 to 17 are attached to the hardware 21 to 27, and the hardware 20 is inserted between the hardware 26 and 27.

  Generally, the two liquid flow paths 31 and 32 are provided through the inside of the cylindrical member 28 and the annular member 29 in the lens barrel (20 to 29), and the through hole of the cylindrical member 28 and the annular member 29 are provided. The through holes are connected. The through hole of the tubular member 28 is a tubular hole formed substantially parallel to the optical axis 10a. The through hole of the annular member 29 is a tubular hole that is formed obliquely with respect to the optical axis 10a and is formed so as to approach the optical axis 10a as it goes downward. The lower ends of the liquid flow paths 31 and 32 are openings 31A and 32A, respectively.

  Here, the immersion objective lens 10 of the first embodiment uses the mounting portion 37 provided at the upper end of the cylindrical member 28 of the lens barrel (20 to 29), and the microscope observation apparatus 40 shown in FIG. Fixed to the body. Furthermore, one of the two liquid flow paths 31 and 32 is connected to the pipe 51 of the liquid supply apparatus 50 of the microscope observation apparatus 40 via the joint 38 on the upper end side. The other liquid flow path 32 is connected to a pipe 61 of the liquid recovery apparatus 60 of the microscope observation apparatus 40 via a joint 39 on the upper end side.

  Then, the liquid flow path 31 on the liquid supply device 50 side has a liquid 30 (see FIG. 5) in the space near the tip 11A of the lens elements 11 to 17 (that is, between the tip 11A and the object for immersion observation). 3 (a)). The liquid 30 is discharged from the opening 31 </ b> A of the liquid flow path 31. In the following description, the liquid passage 31 for supply is referred to as “discharge nozzle 31”. The liquid flow path 32 on the liquid recovery device 60 side is used when recovering the liquid 30 from the space. At this time, the liquid 30 is sucked from the opening 32 </ b> A of the liquid flow path 32. In the following description, the recovery liquid channel 32 is referred to as a “suction nozzle 32”.

  The tip 11A of the lens elements 11 to 17 is the lens surface of the lens element 11 (the tip ball) closest to the object among the lens elements 11 to 17, and has a substantially flat shape. The tip of the hardware 21 for fixing the lens element 11 has a similar shape. The distance δ from these flat tip portions (the surface of diameter d shown in FIG. 3B) to the focal planes of the lens elements 11 to 17 corresponds to the working distance δ of the immersion objective lens 10. The liquid 30 is generally filled in a space from a flat surface having a diameter d to a distance δ (FIG. 3A), and forms “droplets” by surface tension. The lens elements 11 to 14 are designed so that the aberration is corrected when the liquid 30 is filled.

Next, the discharge nozzle 31 and the suction nozzle 32 will be described in detail.
The lower end of the discharge nozzle 31 is an opening 31A, and the liquid 30 is discharged from the opening 31A (FIG. 3A). The opening 31 </ b> A is provided in a portion 29 </ b> A (FIG. 1) facing the space near the tip 11 </ b> A of the lens elements 11 to 17 on the surface of the lens barrel (20 to 29). The portion 29A is a surface that is inclined with respect to the optical axis 10a, and has a shape (annular) around the optical axis 10a while maintaining the inclination angle with respect to the optical axis 10a. The shape of the opening 31A is a small circle as shown in FIG.

  Further, in the discharge nozzle 31, a portion on the opening 31A side (through hole of the annular member 29) is formed obliquely with respect to the optical axis 10a, and the center line 31B (FIG. 3C) is the lens element 11-11. It is provided so as to intersect the optical axis 10a at 17 focal planes. By setting the inclination angle θ of the portion on the opening 31A side as described above, the liquid 30 can be discharged from the opening 31A with the vicinity of the optical axis 10a on the focal plane of the lens elements 11 to 17 as a target. In order to improve the directivity during discharge, it is preferable to determine the size of the opening 31A of the discharge nozzle 31 in consideration of the capability of the liquid supply device 50 of the microscope observation device 40 (FIG. 4).

  In addition, the inclination of the portion 29A (inclined surface) where the opening 31A of the discharge nozzle 31 is provided is preferably determined so as to be substantially orthogonal to the inclination angle θ of the portion on the opening 31A side. By processing in this way, the directivity at the time of discharge can be improved. Further, in consideration of the inclination angle θ of the portion on the opening 31A side, the inclination angle α (FIG. 3 (b)) of the taper portion exposed to the outside of the hardware 21 for fixing the lens element 11 (tip ball) is It is preferable to determine so as to satisfy the relationship “α ≦ θ”.

  On the other hand, the suction nozzle 32 has an opening 32A at one lower end, and sucks the liquid 30 from the opening 32A (FIG. 3A). Similarly to the above-described opening 31A, the opening 32A is provided in a portion 29A (inclined surface) facing the space near the tip 11A of the lens elements 11-17. As shown in FIG. 2B, the shape of the opening 32A is a ring centered on the optical axis 10a, and extends along the circumferential direction of the portion 29A to a portion excluding the opening 31A.

  Therefore, the total area S1 of the opening 31A of the discharge nozzle 31 and the total area S2 of the opening 32A of the suction nozzle 32 satisfy the relationship “S1 ≦ S2”. In the example of FIG. 2B, the total area S2 of the opening 32A is much larger than the total area S1 of the opening 31A. By making the opening 32A larger than the opening 31A and extending along the circumferential direction of the portion 29 (inclined surface), substantially the entire periphery of the liquid 30 can be surrounded by the opening 32A. For this reason, the liquid 30 can be sucked from the entire periphery, and the recovery efficiency is improved.

Further, in the suction nozzle 32, a portion on the opening 32A side (through hole of the annular member 29) is formed obliquely with respect to the optical axis 10a, and an inclination angle thereof is a center line 31B of the portion on the opening 31A side (FIG. 3). The angle is substantially the same as (c)). For this reason, there is also an advantage that the liquid 30 can be sucked efficiently and can be easily processed.
Further, the portion of the suction nozzle 32 on the side of the opening 32A (the through hole of the annular member 29) has a tapered shape in which the cross-sectional area when cut along a plane perpendicular to the optical axis 10a increases downward. A groove 32B as shown in FIG. 3 (d) is provided in the lowermost portion 29 (inclined surface) of the tapered shape in order to ensure a large total area S2 of the opening 32A. The upper side of the groove 32B gradually widens at an angle ψ (FIG. 2B). Thus, the liquid 30 can be efficiently sucked by making the portion on the opening 32A side of the suction nozzle 32 into a tapered shape.

Next, the microscope observation apparatus 40 (FIG. 4) equipped with the immersion objective lens 10 according to the first embodiment will be described.
The microscope observation apparatus 40 includes a stage (41, 42) that supports the substrate 40A to be observed, an immersion observation unit (10, 45), and a mechanism (31, 32, 50, 60). Although not shown, the microscope observation apparatus 40 is also provided with a control unit, a mechanism for automatically transporting the substrate 40A, a TTL autofocus mechanism, and the like. The substrate 40A is a semiconductor wafer or a liquid crystal substrate. The microscope observation apparatus 40 is used for observation (appearance inspection) of defects or foreign matters in a circuit pattern formed on the substrate 40A in the manufacturing process of a semiconductor circuit element or a liquid crystal display element. The circuit pattern is, for example, a resist pattern.

The stage (41, 42) will be described. The stage (41, 42) includes a syringe 41 and an XYZ stage 42. The syringe 41 is supported by an XYZ stage 42 so as to be movable in the vertical direction and movable in a horizontal plane. For example, the substrate 40A is conveyed from the developing device and placed on the upper surface of the syringe 41, and is fixedly supported by, for example, vacuum suction.
The XYZ stage 42 moves the syringe 41 in the vertical direction when focusing the substrate 40A. The focusing operation is performed by a control unit (not shown) using an autofocus mechanism. Further, the XYZ stage 42 moves the syringe 41 within the horizontal plane when positioning a predetermined observation point of the substrate 40A within the visual field of the immersion observation unit (10, 45). The base member of the XYZ stage 42 is fixed to the main body of the microscope observation apparatus 40.

  The immersion observation unit (10, 45) will be described. The immersion observation unit (10, 45) is provided with the immersion objective lens 10 (see FIGS. 1 to 3) of the first embodiment and the eyepiece 45. The immersion objective lens 10 and the eyepiece 45 are each fixed to the main body of the microscope observation apparatus 40. The immersion objective lens 10 is an immersion objective lens, and when the space between the tip and the substrate 40A is filled with the immersion medium (liquid 30), the aberration of the optical system (lens elements 11 to 17). Is designed to be corrected. The tip of the immersion objective lens 10 is a part that touches the liquid 30.

  An illumination light source (not shown) is provided inside the main body of the microscope observation apparatus 40 (between the immersion objective lens 10 and the eyepiece lens 45). The observation wavelength is, for example, a visible region or an ultraviolet region. Note that when an illumination light source having a wavelength in the ultraviolet region is used, observation from the eyepiece lens 45 is not possible. Therefore, a CCD camera or the like is provided instead of the eyepiece lens 45, and an image is taken and displayed on a monitor device for observation.

  In the immersion observation unit (10, 45), an enlarged image (pattern image) of the substrate 40A is formed at the visual field position of the eyepiece 45, and the substrate 40A is observed by this image. Further, the numerical aperture of the immersion objective lens 10 can be made larger than “1” according to the refractive index (> 1) of the liquid 30 filling the space between the tip of the immersion objective lens 10 and the substrate 40A. Compared with a system apparatus (numerical aperture of objective lens ≦ 1), the resolution can be improved reliably.

  Incidentally, the resolution is expressed as “resolution = k × λ / NA” using the numerical aperture NA of the immersion objective lens 10, the observation wavelength λ, and the constant k. When discussing the resolution between two lines, the value of the constant k is normally “0.5”. Further, the numerical aperture NA of the immersion objective lens 10 is expressed as “NA = n” using the opening angle β of the immersion objective lens 10 and the refractive index n of the medium between the immersion objective lens 10 and the substrate 40A. Xsinβ ". Thus, the resolution decreases (increases) in inverse proportion to the increase in the refractive index n between the immersion objective lens 10 and the substrate 40A.

  The mechanism (31, 32, 50, 60) for supplying / recovering the liquid 30 will be described. The mechanism (31, 32, 50, 60) includes a liquid supply device 50, a discharge nozzle 31, a suction nozzle 32, and a liquid recovery device 60. As already described, the discharge nozzle 31 and the suction nozzle 32 penetrate the inside of the lens barrel (20-29) of the immersion objective lens 10 and are integrally provided, and the tips (opening 31A, opening 32A) are liquid. It is disposed near the tip of the immersion objective lens 10.

The liquid supply device 50 includes a pipe 51 connected to the discharge nozzle 31, a two-position switching type electromagnetic valve 52 disposed in the middle of the pipe 51, a liquid tank 53 that contains new clean liquid 5A, and pressurization. It is comprised with a pump (54-57). The pressurizing pump (54 to 57) includes a cylinder 54, a piston 55, a feed screw 56, and a motor 57.
The piston 55 is coupled to a feed screw 56 that converts the power of the motor 57 into linear motion, and can reciprocate in the left-right direction at an arbitrary speed. The moving speed of the piston 55 can be adjusted according to the rotational speed of the motor 57. The moving direction of the piston 55 corresponds to the rotating direction of the motor 57.

  The cylinder 54 is connected to the liquid tank 53 via the first path of the electromagnetic valve 52 and is connected to the discharge nozzle 31 via the second path. However, in the solenoid valve 52, the two paths are not opened at the same time, and only one of them is always opened, and the connected state is set. The electromagnetic valve 52 connects / disconnects the path between the cylinder 54 and the liquid tank 53 in the first path. The electromagnetic valve 52 connects / disconnects the path between the cylinder 54 and the discharge nozzle 31 in the second path.

In the state where the first path is opened in the solenoid valve 52 and the cylinder 54 and the liquid tank 53 are actually connected, the piston 55 is moved in the right direction in the drawing, whereby the liquid 5A inside the liquid tank 53 is moved to the cylinder. 54 (liquid 5B).
In the state where the second path is opened in the solenoid valve 52 and the cylinder 54 and the discharge nozzle 31 are actually connected, the piston 55 is moved in the left direction in the figure, whereby the liquid 5B inside the cylinder 54 is discharged from the discharge nozzle. 31 can be sent out. The delivered liquid 5B is discharged from the tip of the discharge nozzle 31 and reaches between the tip of the immersion objective lens 10 and the substrate 40A (liquid 30). In other words, the liquid 30 is supplied through the discharge nozzle 31 by the liquid supply device 50. The supply of the liquid 30 is automatically performed by a control unit (not shown) before the immersion observation.

  The amount of the liquid 5B delivered from the cylinder 54 to the discharge nozzle 31 (that is, the supply amount V of the liquid 30) is equal to the product of the cross-sectional area S of the cylinder 54 and the movement amount X of the piston 55 (V = S · X). It can be arbitrarily adjusted according to the movement amount X of the piston 55. Further, the supply speed of the liquid 30 can be arbitrarily adjusted according to the moving speed of the piston 55. The moving speed of the piston 55 is preferably set to be slow so that the liquid 30 does not scatter from the tip of the discharge nozzle 31.

  If the supply amount V of the liquid 30 can be made appropriate, the liquid 30 forms “droplets” between the tip of the immersion objective lens 10 and the substrate 40A due to surface tension. That is, it does not flow out to the surroundings, or the bubbles cannot be removed. The liquid 30 flows out to the surroundings when the supply amount V of the liquid 30 is too large and exceeds the limit of the surface tension. In this case, it becomes difficult to collect all the liquid 30 after observation. The bubbles remain when the supply amount V of the liquid 30 is too small. In this case, it becomes difficult to form a clear image by the immersion objective lens 10. The appropriate supply amount V of the liquid 30 is an amount capable of forming a “droplet” between the tip of the immersion objective lens 10 and the substrate 40A due to surface tension.

  The liquid recovery apparatus 60 includes a vacuum buffer tank 62 connected to the suction nozzle 32 via a pipe 61 and a vacuum pump 64 connected to the vacuum buffer tank 62 via a pipe 63. The pipes 61 and 63 are connected to the upper part of the vacuum buffer tank 62. The vacuum buffer tank 62 is provided with a cock 65 for discharging the waste liquid 6A. Instead of the vacuum pump 64, a vacuum device (not shown) in the factory may be connected to the pipe 63.

  In the liquid recovery apparatus 60, the liquid 30 between the tip of the immersion objective lens 10 and the substrate 40A is sucked together with the surrounding air by the vacuum pump 64 through the suction nozzle 32 and the like. That is, the liquid 30 is removed from the substrate 40A. The sucked liquid 30 is guided to the vacuum buffer tank 62 through the pipe 61, where it is separated from the air and falls into the vacuum buffer tank 62 (waste liquid 6A). Only air is guided to the vacuum pump 64 via the pipe 63. Thus, the liquid 30 is recovered by the liquid recovery device 60 via the suction nozzle 32. Since only air is guided to the vacuum pump 64, it is not damaged by the inflow of liquid. A moisture removal filter may be provided in the middle of the pipe 63. Recovery of the liquid 30 is automatically performed by a control unit (not shown) after immersion observation.

  The suction speed (vacuum exhaust speed) by the vacuum pump 64 is such that the suction amount from the suction nozzle 32 is larger than the amount of air leakage caused by the distance between the tip of the immersion objective lens 10 and the substrate 40A. It is preferable to use conditions. This is clear from Bernoulli's theorem. In the middle of the suction operation, the XYZ stage 42 is controlled to raise the syringe 41 slightly (within ≦ δ), thereby reducing the distance between the tip of the immersion objective lens 10 and the substrate 40A. The amount of air leakage due to the above may be reduced. In this case, the liquid 30 remaining on the substrate 40A can be sucked effectively.

  In the present embodiment, for example, pure water is used as the liquid 30 of the immersion medium. Pure water can be easily obtained in large quantities in a semiconductor manufacturing process or the like. Further, since there is no adverse effect on the photoresist on the substrate 40A, a nondestructive inspection of the substrate 40A is possible. In addition, pure water has no adverse effect on the environment, and since the content of impurities is extremely low, an effect of cleaning the surface of the substrate 40A can be expected. The pure water used in the semiconductor manufacturing process is generally called “ultra pure water”. This is more pure than what is commonly referred to as “pure water”. Also in this embodiment, it is more preferable to use ultrapure water.

  Here, among the above-described components, the discharge nozzle 31 and the suction nozzle 32 are made of stainless steel (stainless steel formed by electrolytic polishing to form an oxide film) steel or Teflon (registered trademark) (fluororesin PTFE), and a sealing material is used. It is made of Teflon or fluororubber, all the pipes 51, 61,... Are made of stainless steel or Teflon, and all other surfaces that the liquid 30 touches (the inner surface of the piston 55, the liquid tank 53, the vacuum buffer tank 62, etc.) Is preferably made of the same material. These stainless steels and Teflon are advantageous in that they are chemically stable and impurities (for example, metal ion-based materials) are hardly mixed into the liquid 30.

  Further, in order to monitor the remaining amount of the liquid 5A in the liquid tank 53 of the liquid supply device 50, the liquid tank 53 is equipped with a float sensor (liquid level gauge), an upper limit level sensor, and a lower limit level sensor, and operates the output of each sensor. It is preferable to be able to confirm on the PC screen. Furthermore, it is preferable to display a warning display on the operation PC screen when the liquid 5A reaches the position of the lower limit level sensor. Further, it is preferable that a similar sensor is mounted on the vacuum buffer tank 62 of the liquid recovery apparatus 60 so that a warning display is displayed on the operation PC screen when the waste liquid 6A reaches the position of the upper limit level sensor.

  Next, the observation operation of the substrate 40A in the microscope observation apparatus 40 will be described. The observation operation of the substrate 40A is automatic control by a control unit (not shown). The electromagnetic valve 52 of the liquid supply device 50 is in a state where the second path is opened in the initial state, and the cylinder 54 and the discharge nozzle 31 are actually connected via the pipe 51 and the like. Note that the observation using the microscope observation apparatus 40 corresponds to, for example, an appearance inspection for confirming the cause and state of a defect or foreign matter detected by another defect inspection apparatus.

Prior to the start of the observation operation of the substrate 40A, the control unit calculates an appropriate supply amount V of the liquid 30 (that is, an amount capable of forming “droplets” by surface tension), and realizes this supply amount V. A necessary movement amount X (= V0 / S) of the piston 55 is calculated as a “target value”. Then, after calculating the movement amount X of the piston 55, the observation operation of the substrate 40A is started.
First, the substrate 40A to be observed is transferred to the stage (41, 42) and fixed to the upper surface of the syringe 41. Next, the XYZ stage 42 is controlled, and the syringe 41 is moved in a horizontal plane to position a predetermined observation point of the substrate 40A within the visual field of the immersion objective lens 10. Further, by moving the syringe 41 in the vertical direction and using an autofocus mechanism (not shown), the distance between the tip of the immersion objective lens 10 and the substrate 40A is substantially the desired distance (the working distance δ of the immersion objective lens 10). ) To the position where

  Thereafter, the supply of the liquid 30 is started. That is, the motor 57 of the liquid supply device 50 is rotated to move the feed screw 56, and the piston 55 is moved leftward in the figure. Due to the movement of the piston 55, the liquid 5B inside the cylinder 54 is sent to the discharge nozzle 31 via the electromagnetic valve 52 (second path) and the pipe 51, and between the tip of the immersion objective lens 10 and the substrate 40A. Reach (liquid 30). At this time, the liquid 30 from the opening 31A of the discharge nozzle 31 is discharged using the vicinity of the optical axis 10a of the substrate 40A as a target.

  When the movement amount X of the piston 55 coincides with the “target value” calculated in advance, the motor 57 is stopped. That is, the supply of the liquid 30 is stopped. In this way, by moving the movement amount X of the piston 55 to the “target value” calculated in advance and performing precise quantitative discharge, the liquid 30 supplied between the tip of the immersion objective lens 10 and the substrate 40A. This amount can be an amount capable of forming a “droplet” by surface tension.

  When the supply of the liquid 30 is completed, the immersion observation becomes possible after performing precise focusing by the autofocus mechanism. In this state, the observer performs immersion observation of the observation point of the substrate 40A through the eyepiece lens 45. Since the supply amount V of the liquid 30 is appropriate and no bubbles remain between the tip of the immersion objective lens 10 and the substrate 40A, a clear image of the observation point of the substrate 40A can be observed.

After supplying the liquid 30, the path of the electromagnetic valve 52 of the liquid supply apparatus 50 is switched (that is, the first path is opened) as necessary, and the clean liquid 5A in the liquid tank 53 is taken into the cylinder 54. . Further, after the intake, the path of the electromagnetic valve 52 is switched again so that the cylinder 54 is connected to the discharge nozzle 31.
When receiving the instruction “end of immersion observation” from the observer, the control unit controls the vacuum pump 64 of the liquid recovery apparatus 60 and the tip of the immersion objective lens 10 and the substrate via the suction nozzle 32 and the like. The liquid 30 is recovered from between 40A. That is, no “droplet” is left on the substrate 40A. At this time, the liquid 30 on the substrate 40A is efficiently sucked from the opening 32A provided so as to surround substantially the entire periphery thereof.

When there is another observation point in the substrate 40A, the above operation is repeated. When immersion observation is completed for all observation points, the substrate 40A is recovered from the stage (41, 42), and the observation operation of the substrate 40A is completed.
As described above, in the first embodiment, since the discharge nozzle 31 and the suction nozzle 32 are integrally provided through the inside of the lens barrel (20 to 29) of the immersion objective lens 10, the immersion objective lens 10 The supply / recovery mechanism (31, 32, 50, 60) of the liquid 30 can be arranged while simplifying the peripheral structure. As a result, downsizing of the microscope observation apparatus 40 is realized. Therefore, it is possible to efficiently observe the substrate 40A by the liquid immersion method using the compact microscope observation apparatus 40.

  Furthermore, in the first embodiment, the tip of the discharge nozzle 31 and the suction nozzle 32 (opening 31A, opening 32A) can be selected according to the processing accuracy of the annular member 29 of the immersion objective lens 10 without providing a high-precision alignment mechanism. ) Can be accurately positioned near the tip of the immersion objective lens 10. Further, even if the numerical aperture NA of the immersion objective lens 10 is large and the working distance δ is very small (for example, about 0.1 to 0.2 mm), the tips of the discharge nozzle 31 and the suction nozzle 32 ( The openings 31A and 32A) can be reliably positioned.

  In the first embodiment, the inclination angle θ of the portion of the discharge nozzle 31 on the opening 31A side is set so that the center line 31B (FIG. 3C) of the portion on the opening 31A side is light on the focal plane of the lens elements 11-17. Since the axis is set so as to intersect with the axis 10a, the liquid 30 can be discharged with the vicinity of the optical axis 10a of the substrate 40A positioned on the focal plane of the lens elements 11 to 17 as a target. Accordingly, a “droplet” can be quickly formed between the tip of the immersion objective lens 10 and the substrate 40A.

Furthermore, in the first embodiment, since the total areas S1 and S2 of the openings 31A and 32A of the discharge nozzle 31 and the suction nozzle 32 satisfy the relationship “S1 <S2”, the liquid 30 can be efficiently collected. In particular, when the groove 32B shown in FIG. 3D is provided at the tip of the suction nozzle 32, the liquid 30 can be sucked along the groove 32B, and the recovery efficiency is improved.
In the microscope observation apparatus 40 of the first embodiment, the liquid 30 is automatically supplied and collected during the immersion observation, so that there is almost no burden on the operator and the immersion observation of the substrate 40A can be performed with high throughput. It can be carried out.
(Second Embodiment)
As shown in FIGS. 5A and 5B, the immersion objective lens 70 of the second embodiment is provided with two discharge nozzles 71 in place of the discharge nozzle 31 of the first embodiment (FIG. 2). Instead of the suction nozzle 32 of the first embodiment, two suction nozzles 72 are provided, and other configurations are the same as those of the immersion objective lens 10 of the first embodiment. 5A corresponds to the AA cross section of FIG. 1, and FIG. 5B is a view of the immersion objective lens 70 as viewed from below.

The two discharge nozzles 71 are arranged symmetrically across the optical axis 70a, and are connected to the liquid supply device 50 of the microscope observation apparatus 40 shown in FIG. The shape of the opening 71A of the discharge nozzle 71 is a small circle.
The two suction nozzles 72 are arranged symmetrically with the optical axis 70 a interposed therebetween, and are connected to the liquid recovery device 60 of the microscope observation device 40 via a joint 75 and a pipe 76. The shape of the opening 72A of the suction nozzle 72 is an annular shape centered on the optical axis 70a, and extends to a portion excluding the above-described opening 71A along the circumferential direction of the portion 29A.

  As described above, in the second embodiment, the discharge nozzle 71 and the suction nozzle 72 are integrally provided through the inside of the lens barrel (20 to 29) of the immersion objective lens 70. The supply / recovery mechanism (31, 32, 50, 60) of the liquid 30 can be arranged while simplifying the peripheral structure. As a result, downsizing of the microscope observation apparatus 40 is realized. Therefore, it is possible to efficiently observe the substrate 40A by the liquid immersion method using the compact microscope observation apparatus 40.

  In the second embodiment, since two discharge nozzles 71 and two suction nozzles 72 are provided, the liquid 30 can be supplied and recovered more efficiently. In particular, since the two discharge nozzles 71 are arranged symmetrically with respect to the optical axis 70a and the liquid 30 is discharged with the vicinity of the optical axis 70a as a target, respectively, between the tip of the immersion objective lens 70 and the substrate 40A. It can quickly form “droplets” with good symmetry.

Furthermore, also in the second embodiment, the total area S1, S2 of the openings 71A, 72A of the discharge nozzle 71 and the suction nozzle 72 satisfies the relationship “S1 <S2”, so that the liquid 30 can be efficiently recovered.
(Third embodiment)
As shown in FIGS. 6A and 6B, the immersion objective lens 80 of the third embodiment is provided with three suction nozzles 81 instead of the suction nozzle 32 (FIG. 2) of the first embodiment. The suction nozzle 81 has a common opening 81A, and other configurations are the same as those of the immersion objective lens 10 of the first embodiment. 6A corresponds to the AA cross section of FIG. 1, and FIG. 6B is a view of the immersion objective lens 80 as viewed from below.

The three suction nozzles 81 are connected to the liquid recovery apparatus 60 of the microscope observation apparatus 40 shown in FIG. The shape of the opening 81A of the three suction nozzles 81 is an annular shape centering on the optical axis 80a, and extends to a portion excluding the above-described opening 31A along the circumferential direction of the portion 29A.
As described above, in the third embodiment, the discharge nozzle 31 and the suction nozzle 81 are integrally provided through the inside of the lens barrel (20 to 29) of the immersion objective lens 80. The supply / recovery mechanism (31, 32, 50, 60) of the liquid 30 can be arranged while simplifying the peripheral structure. As a result, downsizing of the microscope observation apparatus 40 is realized. Therefore, it is possible to efficiently observe the substrate 40A by the liquid immersion method using the compact microscope observation apparatus 40.

In the third embodiment, since the three suction nozzles 81 are provided, the liquid 30 can be collected more efficiently.
(Fourth embodiment)
As shown in FIGS. 7A and 7B, the immersion objective lens 90 of the fourth embodiment is provided with six suction nozzles 91 in place of the suction nozzle 72 (FIG. 5) of the second embodiment. Other configurations are the same as those of the immersion objective lens 10 of the first embodiment. 7A corresponds to the AA cross section of FIG. 1, and FIG. 7B is a view of the immersion objective lens 90 as viewed from below.

  The six suction nozzles 91 are connected to the liquid recovery apparatus 60 of the microscope observation apparatus 40 shown in FIG. The shapes of the openings 81A of the six suction nozzles 81 are small circles, respectively. Each of the six suction nozzles 81 on the opening 81 </ b> A side (through hole of the annular member 29) has a substantially constant cross-sectional area, like the discharge nozzle 71. Further, in the immersion objective lens 90, the groove of the portion 29 (inclined surface) is omitted.

  As described above, in the fourth embodiment, the discharge nozzle 71 and the suction nozzle 91 are integrally provided through the inside of the lens barrel (20 to 29) of the immersion objective lens 90. The supply / recovery mechanism (31, 32, 50, 60) of the liquid 30 can be arranged while simplifying the peripheral structure. As a result, downsizing of the microscope observation apparatus 40 is realized. Therefore, it is possible to efficiently observe the substrate 40A by the liquid immersion method using the compact microscope observation apparatus 40.

Moreover, in 4th Embodiment, since the suction nozzle 91 is comprised by a small round hole (hole with a substantially constant cross-sectional area), there exists an advantage that it is easy to process. Since a large number (six) of suction nozzles 91 are provided, the recovery efficiency of the liquid 30 does not decrease.
(Fifth embodiment)
As shown in FIGS. 8A and 8B, the immersion objective lens 95 of the fifth embodiment includes two discharge / suction nozzles 96 instead of the discharge nozzle 71 (FIG. 7) of the fourth embodiment. The other configurations are the same as those of the immersion objective lens 10 of the first embodiment. 8A corresponds to the AA cross section of FIG. 1, and FIG. 8B is a view of the immersion objective lens 95 as viewed from below.

  The two discharge / suction nozzles 96 are connected to both the liquid supply device 50 and the liquid recovery device 60 of the microscope observation apparatus 100 shown in FIG. However, a two-position switching type solenoid valve 101 is arranged in the middle of the pipe 98, and the discharge / suction combined nozzle 96 and the liquid supply device 50 are actually connected only when one path of the solenoid valve 101 is opened. Is done. Further, only when the other path of the electromagnetic valve 101 is opened, the discharge / suction combined nozzle 96 and the liquid recovery device 60 are actually connected.

  As described above, in the fifth embodiment, since the discharge / suction combined nozzle 96 and the suction nozzle 91 are provided integrally through the inside of the lens barrel (20 to 29) of the immersion objective lens 95, the immersion objective The supply / recovery mechanism (31, 32, 50, 60) of the liquid 30 can be arranged while simplifying the structure around the lens 95. As a result, downsizing of the microscope observation apparatus 100 is realized. Therefore, it is possible to efficiently observe the substrate 40A by the liquid immersion method using the compact microscope observation apparatus 100.

In the fifth embodiment, since the two discharge / suction nozzles 96 and the six suction nozzles 91 are used for suction from the entire periphery of the liquid 30, the recovery efficiency of the liquid 30 is improved. Furthermore, since all the nozzles (91, 96) are constituted by small round holes, there is an advantage that they are easy to process. Further, since the common nozzle functioning as the discharge nozzle or the suction nozzle (that is, the discharge / suction combination nozzle 96) is provided, the inside of the lens barrel (20 to 29) of the immersion objective lens 95 can be used effectively. The number of discharge / suction nozzles 96 is not limited to two as described above, and may be one or three or more.
(Modification)
In the above-described embodiment, the example in which the total area S2 of the suction nozzle (including the discharge / suction / combining nozzle) opening is larger than the total area S1 of the discharge nozzle opening has been described. However, the present invention is not limited thereto. Not. The present invention can also be applied when the total areas S1 and S2 are the same. In this case, the liquid 30 can be recovered satisfactorily.

  In the embodiment described above, an example in which the discharge nozzle and the suction nozzle are provided separately (first embodiment to fourth embodiment) and an example in which the discharge / suction combined nozzle is partially provided (fifth embodiment) are provided. Although described, the present invention is not limited to this. The present invention can also be applied to the case where all nozzles are used for both discharge and suction. When all the discharge / suction nozzles are used, the number of liquid flow paths (discharge / suction nozzles) provided in the immersion objective lens can be reduced to one.

  Furthermore, in the above-described embodiment, when the portion on the opening side of the suction nozzle (the through hole of the annular member 29) is tapered, the groove 32B is provided in the portion 29 (inclined surface). It is not limited. The present invention can also be applied to a case in which the groove 32B is omitted and a tapered shape is formed only by a portion that gradually widens at an angle ψ (FIG. 2B). The tapered shape may be a combination of a small round hole (a hole having a substantially constant cross-sectional area) and the groove 32B.

  In the above-described embodiment, the inclination angle θ is set so that the center line of the discharge nozzle opening side portion (through hole of the annular member 29) intersects the optical axis 10 a at the focal plane of the lens elements 11 to 17. However, the present invention is not limited to this. The inclination angle θ may be set so that the center line of the opening side portion intersects the optical axis 10a on a surface below the focal plane (a surface away from the lens element). In this case, the liquid 30 can be discharged from the opening 31A with the vicinity of the optical axis 10a on the surface below the focal plane (the surface away from the lens element) as a target.

  Furthermore, in the above-described embodiment, the immersion objective lens 10 is fixed to the main body of the microscope observation apparatus 40, but the present invention is not limited to this. The immersion objective lens 10 may be attached to the revolver so that it can be switched to another dry objective lens. In the above-described embodiment, in the liquid supply device 50, the piston 55 is driven by the motor 57 and the feed screw 56, but an air cylinder may be provided instead. In this case, it is preferable to provide limit sensors at both ends of the stroke of the air cylinder. Further, although the liquid tank 53 is used as a means for supplying pure water, pure water may be supplied using a pure water manufacturing apparatus or the like.

  In the above-described embodiment, an example of immersion observation using the eyepiece 45 has been described, but the present invention is not limited to this. An imaging element and a monitor may be provided, and immersion observation may be performed using a display image on the monitor. Both immersion observation with the eyepiece 45 and immersion observation with the imaging device and the monitor may be performed, or either one may be performed. However, when the observation wavelength is in the ultraviolet region (for example, the deep ultraviolet region), it is preferable to omit the eyepiece and provide an image sensor and a monitor. Moreover, when making an observation wavelength into an ultraviolet region, it is preferable to fill the inside of the main body of the microscope observation apparatus 40 with nitrogen. Although the optical path between the immersion objective lens 10 and the substrate 40A is not filled with nitrogen, the ultraviolet light causes a photochemical reaction with the surrounding air (oxygen) in order to perform observation with ultraviolet light after the liquid 30 is supplied. There is no.

  Furthermore, in the above-described embodiment, the example in which the liquid 30 is supplied / recovered for each observation point of the substrate 40A has been described, but the present invention is not limited to this. When the distance to the next observation point on the substrate 40A is short, the XYZ stage 42 (that is, the substrate 40A) may be moved without collecting the liquid 30 supplied to the current observation point. When the surface of the substrate 40A has a certain degree of hydrophobicity and the tip of the immersion objective lens 10 has a certain degree of hydrophilicity, the liquid 30 continues to adhere to the immersion objective lens 10 side. For this reason, even if the XYZ stage 42 (that is, the substrate 40A) is moved, the liquid 30 can be attached to the tip of the immersion objective lens 10, and the same liquid 30 is used when it reaches the next observation point. Can be observed.

  In the above embodiment, pure water is used as the liquid 30 (water immersion system), but the present invention is not limited to this. In addition, oil (for example, immersion oil or silicone oil) having a higher refractive index than pure water may be used as the liquid 30 (oil immersion system). In this case, in order to move the XYZ stage 42 (that is, the substrate 40A) while adhering the liquid 30 to the tip of the immersion objective lens 10, the surface of the substrate 40A has a certain degree of hydrophilicity, and the tip of the immersion objective lens 10 is moved. Preferably have a certain degree of hydrophobicity.

Furthermore, a liquid having a surface tension smaller than that of pure water (for example, a liquid to which a surfactant is added, an alcohol, or a mixture of these and pure water) can also be used as the liquid 30. In this case, even when the circuit pattern of the substrate 40A is fine, the liquid 30 can be reliably infiltrated into the recesses of the circuit pattern and can be observed well.
Further, in the above-described embodiment, the liquid 30 is recovered using the suction nozzle 32 and the liquid recovery device 60 in order to remove the liquid 30 from the substrate 40A after the observation in the immersion system. It is not limited to. The liquid 30 may be removed using any drying means (for example, drying under reduced pressure). In this case, the liquid flow path (one or more) provided in the lens barrel of the immersion objective lens is used only as a discharge nozzle.

  Furthermore, in the above-described embodiment, the immersion observation of a semiconductor wafer, a liquid crystal substrate, or the like has been described as an example, but the present invention is not limited to this. In addition, the immersion objective lens of the present invention can be used for immersion observation of biological specimens (for example, cells).

It is a longitudinal cross-sectional view of the immersion objective lens 10 of 1st Embodiment. FIG. 2A is a cross-sectional view of the immersion objective lens 10 along AA (a), and FIG. 2 is a longitudinal sectional view for explaining a tip portion of the immersion objective lens 10. FIG. 2 is a side view showing an overall configuration of a microscope observation apparatus 40. FIG. It is a block diagram of the immersion objective lens 70 of 2nd Embodiment. It is a block diagram of the immersion objective lens 80 of 3rd Embodiment. It is a block diagram of the immersion objective lens 90 of 4th Embodiment. It is a block diagram of the immersion objective lens 95 of 5th Embodiment. 1 is a side view showing an overall configuration of a microscope observation apparatus 100. FIG.

Explanation of symbols

10, 70, 80, 90, 95 Immersion objective lens 11-17 Lens element 20-27 Hardware 28 Cylindrical member 29 Annular member 30 Liquid 31, 71 Liquid flow path (discharge nozzle)
32, 72, 81, 91 Liquid channel (suction nozzle)
40,100 Microscope observation device 40A Substrate 41 Syringe 42 XYZ stage 45 Eyepiece 50 Liquid supply device 51, 61, 63, 98 Piping 52, 101 Solenoid valve 53 Liquid tank 54 Cylinder 55 Piston 56 Feed screw 57 Motor 60 Liquid recovery device 62 Vacuum buffer tank 64 Vacuum pump 96 Liquid flow path (Discharge / Suction nozzle)

Claims (4)

One or more lens elements;
A lens barrel holding the lens element;
A supply liquid channel that passes through the interior of the lens barrel and supplies liquid to a space near the tip of the lens element, and is provided independently of the supply liquid channel and collects the liquid in the space A recovery liquid flow path ,
The openings of the supply liquid flow path and the recovery liquid flow path are respectively provided in portions facing the space near the tip, and the portion of the recovery liquid flow path that is close to the space tapers toward the space. An immersion objective lens having a shape . The immersion objective according to claim 1.
The immersion objective lens, wherein the total area S1 of the opening of the supply liquid flow path and the total area S2 of the opening of the recovery liquid flow path satisfy a relationship of S1 ≦ S2. The immersion objective lens according to claim 1 or 2,
In the supply liquid channel, the opening side portion is formed obliquely with respect to the optical axis of the lens element, and the center line of the portion is the focal plane of the lens element or the lens element is closer to the focal plane. An immersion objective lens, wherein the immersion objective lens is provided so as to intersect the optical axis on a surface away from the optical axis. Supporting means for supporting the substrate to be observed;
The immersion objective lens according to any one of claims 1 to 3,
Supply means for supplying liquid to the space between the tip of the lens element and the substrate using the supply liquid flow path ;
A microscope observation apparatus comprising: a recovery unit that recovers the liquid from the space using the recovery liquid channel .

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