JP2007206404A - Objective and optical device equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an objective for a microscope having a long actuation distance, achieving facilitation of an operation to insert/pull out or replace a sample, and further, achieving complete correction of chromatic aberration, and simultaneously performing high-resolution observation and highly accurate repair of a defect by making an image forming position by observation wavelength in macroscopic observation or observation through a television camera, an image forming position by laser wavelength for repair in the repair of a defective part and an image forming position with infrared light in autofocus using an infrared region close to each other, and to provide an optical device equipped therewith. <P>SOLUTION: The objective is constituted of a first lens group G1 having positive refractive power, a second lens group G2 having positive refractive power, and a third lens group G3 having negative refractive power in order from an object side, and satisfies a following conditional expression: 0.3<F/WD<20.5<F/¾f3¾<1.5, provided that F is the focal distance of an entire system on a d-line, WD is the actuation distance and f3 is the focal distance of the third lens group on a d-line. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an objective lens of a microscope used in, for example, a laser repair apparatus, and particularly has an optical performance with a high transmittance in the near ultraviolet region, and at the same time an optical performance in the visible region is good, and aberrations over a wide wavelength region. The present invention relates to an objective lens in which is corrected and an optical apparatus including the same.

  Recently, in observation and inspection of semiconductor ICs and liquid crystal panels using a microscope device, in addition to observation with the naked eye or TV camera, for example, a semiconductor IC or the like as a laser repair device combining a Yag laser or the like with a microscope device In many cases, repairs are made to the defective parts. In such a case, it is desirable that the working distance of the microscope objective lens is large in order to easily perform operations such as insertion and removal of the specimen and replacement.

  In general, the glass material (optical glass) constituting the objective lens has a low transmittance in the ultraviolet region. However, in the laser repair device, if the transmittance of the ultraviolet light of the objective lens is low, the irradiation energy at the sample position becomes small, and the defect portion cannot be removed by one-time irradiation of the repair laser light. It becomes necessary to irradiate the laser light twice, resulting in an increased burden in terms of time and cost. For this reason, it is preferable that the transmittance of ultraviolet light in the objective lens is high. In the objective lens, it is desirable to correct aberrations in a wide wavelength range while using a limited glass material so that high transmittance can be maintained in the ultraviolet range.

However, conventionally, as an objective lens having a high transmittance in the ultraviolet region, for example, near-infrared objective lenses described in the following Patent Documents 1 to 3 have been proposed.
Japanese Patent Laid-Open No. 11-142744 JP-A-11-223774 JP 2000-62118 A

The near-ultraviolet objective lens described in Patent Document 1 has a long working distance.
However, in the aberration correction, the near-ultraviolet region is mainly emphasized over visible light such as C-line, d-line, and F-line.
Further, the lens configuration is composed of 17 elements in 10 groups, and the focal distance corresponds to about 155 mm, so that a compact system cannot be configured.
Furthermore, from the viewpoint of aberration correction, the imaging position of the observation light in the naked-eye observation or TV camera observation, the imaging position of the infrared light used for autofocus, and the wavelength for repairing the defective part, For example, the imaging position of light of 355 nm, which is the fourth harmonic of a Yag laser, does not match. For this reason, even if the imaging position is shifted, chromatic aberration occurs in the visible region, and sufficient imaging performance cannot be obtained.

The near-ultraviolet objective lens described in Patent Document 2 is a near-ultraviolet objective lens having a long working distance that simultaneously performs specimen observation and specimen processing, and has a configuration of 16 elements in 7 groups with a focal distance of about 63 mm. It has become.
Also, from the viewpoint of aberration correction, the difference between the imaging position of the observation light in the naked eye observation and TV camera observation and the imaging position of the laser beam for repairing the defective part is small, but autofocusing The axial chromatic aberration is not sufficiently corrected up to the imaging position of the infrared light used, for example, 785 nm light. For this reason, with the objective lens described in Patent Document 2, autofocus is difficult.

The near-ultraviolet objective lens described in Patent Document 3 has a configuration of 13 elements in 8 groups with a focal distance of about 63 mm.
Further, from the viewpoint of aberration correction, the aberration is corrected from the d-line to the i-line, and from the observation wavelength for visual observation or television camera observation to the wavelength for repairing the defective portion is sufficiently corrected. However, the objective lens described in Patent Document 3 has a short working distance and lacks operability. For this reason, it is insufficient as an objective lens for laser repair.

  The present invention has been made in view of the above-mentioned conventional problems, has a long working distance, can easily perform operations such as insertion / removal of a specimen, exchange, etc., and sufficiently performs chromatic aberration correction. In addition, the imaging position of the observation wavelength during observation with the naked eye and the TV camera, the imaging position of the repair laser wavelength (for example, the fourth harmonic of Yag 355 nm) at the time of defect repair, and auto using the infrared region To provide a microscope objective lens capable of simultaneously performing high-resolution observation and highly-accurate defect repair by bringing an infrared imaging position in focus (for example, 785 nm) close to the imaging position, and an optical device including the same. With the goal.

In order to achieve the above object, an objective lens according to the present invention includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a first lens group having a negative refractive power. It is composed of three lens groups and satisfies the following conditional expressions (1) and (2).
0.3 <F / WD <2 (1)
0.5 <F / | f3 | <1.5 (2)
Where F is the focal length of the entire system at the d-line, WD is the working distance, and f3 is the focal length of the third lens group at the d-line.

In the objective lens of the present invention, it is preferable that the following conditional expression (3) is satisfied.
0.6 <f2 / f1 <1.67 (3)
Here, f1 is the focal length of the first lens group at the d-line, and f2 is the focal length of the second lens group at the d-line.

Further, the objective lens of the present invention includes at least one cemented lens, and in at least two of the glass materials constituting the cemented lens, the difference in refractive index at d line is Δn, and the Abbe number at d line. It is preferable that the following conditional expressions (4) and (5) are satisfied, where Δν is Δν.
0.17 <| Δn | (4)
42 <| Δν | (5)

The objective lens according to the present invention includes at least one cemented lens, and the cemented lens includes a convex lens and a meniscus lens, and the convex lens has the following conditional expression when Δθgd is anomalous dispersion in the d-line: It is preferable to satisfy (6).
0.03 <Δθgd (6)

  An optical device according to the present invention includes any one of the objective lenses according to the present invention.

  According to the present invention, it has a long working distance, and can easily perform operations such as insertion / removal of a specimen, replacement, etc., and is sufficiently corrected for chromatic aberration, and observation during observation with a naked eye or a TV camera. The imaging position of the wavelength, the imaging position of the repair laser wavelength (for example, the fourth harmonic of Yag 355 nm) at the time of repairing the defect portion, and the imaging of the infrared light in the autofocus (for example, 785 nm) using the infrared region A microscope objective lens capable of simultaneously performing high-resolution observation and high-precision defect repair by bringing the position close to each other and an optical apparatus including the same are obtained.

Prior to the description of the embodiments, the effects of the present invention will be described.
The objective lens of the present invention includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a negative refractive power. The following conditional expressions (1) and (2) are satisfied.
0.3 <F / WD <2 (1)
0.5 <F / | f3 | <1.5 (2)
Where F is the focal length of the entire system at the d-line, WD is the working distance, and f3 is the focal length of the third lens group at the d-line.

If the lower limit of conditional expression (1) is not reached, the working distance WD becomes too large, and it becomes necessary to bend the light beam in a short space in order to obtain the power of the focal length F of the entire system in the d line. Will be increased, and spherical aberration, astigmatism, off-axis coma, etc. will increase.
On the other hand, when the upper limit value of conditional expression (1) is exceeded, the working distance WD becomes too small, the operability becomes worse, and processing powder such as resist generated when repairing is likely to adhere to the lens. Since it is necessary to remove the deposits by wiping, it is disadvantageous in terms of time and man-hours.
The following conditional expression (1 ′) is preferably satisfied, and more preferably, the following conditional expression (1 ″) is satisfied.
0.5 <F / WD <1.5 (1 ')
0.7 <F / WD <1.2 (1 ")

If the lower limit value of conditional expression (2) is not reached, the focal length f3 of the third lens group at the d-line becomes too large, and the focal length of the combined group of the second lens group and the third lens group at the d-line. Also grows. As a result, the power of anomalous dispersion at the g-line included in the combined group of the second lens group and the third lens group becomes too small, and chromatic aberration at a short wavelength cannot be sufficiently corrected. .
On the other hand, if the upper limit value of conditional expression (2) is exceeded, the refractive power of the third lens group at the d-line becomes too large, and the refractive power of the group of the first lens group and the second lens group at the d-line is also large. The radius of curvature becomes too small. For this reason, the spherical aberration becomes large in the region where the ray height is high.
It is preferable that the following conditional expression (2 ′) is satisfied.
0.75 <F / | f3 | <1.2 (2 ')

The objective lens according to the present invention preferably satisfies the following conditional expression (3).
0.6 <f2 / f1 <1.67 (3)
Here, f1 is the focal length of the first lens group at the d-line, and f2 is the focal length of the second lens group at the d-line.

If the lower limit of conditional expression (3) is not reached, the focal length f2 of the second lens group at the d-line becomes too small. For this reason, the radius of curvature of the second lens group becomes too small, and the occurrence of off-axis coma becomes large.
On the other hand, if the upper limit of conditional expression (3) is exceeded, the focal length f2 of the second lens group at the d-line becomes too large, and the convex power of the second lens group becomes small. Then, the power of anomalous dispersion of g-line contained in the second lens group becomes too small, and short wavelength chromatic aberration cannot be sufficiently corrected.
More preferably, the following conditional expression (3 ′) should be satisfied.
0.8 <f2 / f1 <1.3 (3 ')

The objective lens according to the present invention preferably includes at least one cemented lens, and the difference in refractive index between d-line in Δn and d-line in at least two of the glass materials constituting the cemented lens. When the Abbe number difference is Δν, the following conditional expressions (4) and (5) should be satisfied.
0.17 <| Δn | (4)
42 <| Δν | (5)

  If the conditional expressions (4) and (5) are not satisfied, it is difficult to sufficiently correct the axial chromatic aberration, and the chromatic aberration of magnification also increases at the same time. In addition, the spherical aberration of the portion of the short wavelength (355 nm) where the ray height is high increases, and the coma aberration also increases.

In the objective lens according to the present invention, it is preferable that the objective lens includes at least one cemented lens. The cemented lens includes a convex lens and a meniscus lens. It is preferable that the conditional expression (6) is satisfied.
0.03 <Δθgd (6)

One glass material having a large anomalous dispersion Δθgd is an FPL-based glass material. Since this FPL-based glass material has a small refractive index, the curvature radius tends to be small when it is made to act as a convex lens. However, if the radius of curvature is small, edge breakage is likely to occur when an effective diameter is set, and spherical aberration and coma aberration are likely to occur at a portion where the ray height is high.
In order to avoid this and maintain a certain amount of optical power, it is preferable to join a meniscus lens to a convex lens made of a glass material having a large anomalous dispersion Δθgd. When cemented with a meniscus lens, the light beam can be further bent at the meniscus lens, so that the optical power that the convex lens alone was insufficient can be distributed to the meniscus lens, and the radius of curvature of the glass material with large anomalous dispersion should be set large. Is possible. Therefore, a fixed amount of combined focal length can be maintained, and at the same time, the power of anomalous dispersion for color correction can be obtained from a lens with a large anomalous dispersion, reducing coma and spherical aberrations, and at the same time providing sufficient anomalous dispersion effects. Can be used.

  Furthermore, in the objective lens of the present invention, it is preferable that all the glass materials constituting the third lens group have a negative value for the anomalous dispersion Δθgd in the g-line.

  The first lens group and the second lens group have anomalous dispersion having a strong positive power in the g-line. For this reason, if the lenses constituting the third lens group have positive anomalous dispersion in the g-line, color correction becomes excessive.

  In the objective lens of the present invention, it is preferable that aberration correction is performed so that axial chromatic aberration at 355 nm to 785 nm is within 20 μm.

When the axial chromatic aberration is 20 μm or more, the imaging position of the observation light by visible light and the focus position of the 355 nm laser light for repair are different. Further, when capturing 785 nm for AF with a sensor, a dedicated chromatic aberration correction lens is required, which increases the burden in terms of operation and cost.
More preferably, the axial chromatic aberration in the wavelength range is within 15 μm, and even more preferably within 10 μm.

In the objective lens of the present invention, it is preferable that the peripheral light amount outside the most axis is 90% or more of the light amount in the central portion.
If the objective lens for laser repair has a small amount of peripheral light, a difference occurs in the energy density of the irradiated laser between the central portion and the peripheral portion of the test surface during processing, and processing unevenness occurs.
More preferably, the peripheral light amount off the most axis is configured to be 95% or more of the light amount at the center.

In the objective lens according to the present invention, it is preferable that the ray height of the principal ray of the most off-axis light beam with respect to the most off-axis marginal ray height is less than 10% on all surfaces.
When the ray height of the principal ray of the most off-axis light beam with respect to the off-axis marginal ray height is 10% or more, the region through which the light beam passes through each lens greatly deviates from the center of the lens, resulting in large coma aberration. End up. Furthermore, off-axis vignetting is likely to occur, and the amount of peripheral light is also reduced.

  Next, embodiments of the present invention will be described with reference to the drawings.

1 is a cross-sectional view along the optical axis showing the optical configuration of an objective lens according to Example 1 of the present invention, and FIG. 2 is a diagram showing spherical aberration, astigmatism, coma aberration, and distortion of the objective lens shown in FIG. It is. The aberration diagram of FIG. 2 shows the light ray shown in FIG.
The objective lens of Example 1 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a negative refractive power. It consists of and.
The first lens group G1 includes, in order from the object side, a positive meniscus lens L11 having a concave surface directed toward the object side, and a cemented lens L12 of a biconvex lens L12 ₁ , a biconcave lens L12 _2, and a biconvex lens L12 ₃ . .
The second lens group G2, a cemented lens L21 of a negative meniscus lens L21 ₃ having a concave surface facing the negative meniscus lens L21 ₁ biconvex lens L21 ₂ and the object side with a convex surface on the object side, a biconvex lens L22 ₁ with the object And a cemented lens L22 with a negative meniscus lens L22 ₂ having a concave surface on the side.
The third lens group G3 includes a biconcave lens L31, and a biconvex lens L32 ₁ and a cemented lens L32 of a biconcave lens L32 _2.

Next, numerical data of optical members constituting the objective lens of Example 1 are shown.
In the numerical data of Example 1, r ₁ , r ₂ ,... Are the radius of curvature of each lens surface, d ₁ , d ₂ ,... Are the thickness or air spacing of each lens, n _d1 , n _d2,. The refractive index of each lens at the d-line, ν _d1 , ν _d2 ,... Represents the Abbe number of each lens at the d-line.
These symbols are common to numerical data in the embodiments described later.

Numerical data 1 (Example 1)
r ₀ = ∞ (object surface) d ₀ = 10.30
r ₁ = -15.5 d ₁ = 3.70 n _d1 = 1.773 ν _d1 = 49.6
r ₂ = -9.6 d ₂ = 0.50
r ₃ = 23.9 d ₃ = 3.30 n _d3 = 1.439 ν _d3 = 94.9
r ₄ = -13.7 d ₄ = 1.30 n _d4 = 1.518 ν _d4 = 58.9
r ₅ = 18.8 d ₅ = 3.30 n _d5 = 1.439 ν _d5 = 94.9
r ₆ = -18.8 d ₆ = 0.50
r ₇ = 25.7 d ₇ = 1.30 n _d7 = 1.741 ν _d7 = 52.6
r ₈ = 10.9 d ₈ = 4.30 n _d8 = 1.439 ν _d8 = 94.9
r ₉ = -16.0 d ₉ = 1.30 n _d9 = 1.673 ν _d9 = 38.2
r ₁₀ = -66.5 d ₁₀ = 1.10
r ₁₁ = 10.4 d ₁₁ = 4.30 n _d11 = 1.439 ν _d11 = 94.9
r ₁₂ = -16.3 d ₁₂ = 1.50 n _d12 = 1.673 ν _d12 = 38.2
r ₁₃ = -20.3 d ₁₃ = 1.10
r ₁₄ = -17.0 d ₁₄ = 1.60 n _d14 = 1.589 ν _d14 = 61.1
r ₁₅ = 12.7 d ₁₅ = 1.40
r ₁₆ = 12.1 d ₁₆ = 4.10 n _d16 = 1.673 ν _d16 = 38.2
r ₁₇ = -21.8 d ₁₇ = 2.10 n _d17 = 1.516 ν _d17 = 64.1
r ₁₈ = 7.5

3 is a cross-sectional view along the optical axis showing the optical configuration of the objective lens according to Example 2 of the present invention, and FIG. 4 is a diagram showing the spherical aberration, astigmatism, coma aberration, and distortion of the objective lens shown in FIG. It is. Note that the aberration diagram of FIG. 4 shows the rays shown in FIG.
The objective lens of Example 2 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a negative refractive power. It consists of and.
The first lens group G1 includes, in order from the object side, a positive meniscus lens L11 having a concave surface directed toward the object side, and a cemented lens L12 of a biconvex lens L12 ₁ , a biconcave lens L12 _2, and a biconvex lens L12 ₃ . .
The second lens group G2, a cemented lens L21 of a negative meniscus lens L21 ₃ having a concave surface facing the negative meniscus lens L21 ₁ biconvex lens L21 ₂ and the object side with a convex surface on the object side, a biconvex lens L22 ₁ with the object And a cemented lens L22 with a negative meniscus lens L22 ₂ having a concave surface on the side.
The third lens group G3 includes a biconcave lens L31, and a biconvex lens L32 ₁ and a cemented lens L32 of a biconcave lens L32 _2.

Next, numerical data of optical members constituting the objective lens of Example 2 are shown.
Numerical data 2 (Example 2)
r ₀ = ∞ (object surface) d ₀ = 12.00
r ₁ = -19.662 d ₁ = 2.43 n _d1 = 1.755 ν _d1 = 52.3
r ₂ = -9.535 d ₂ = 1.21
r ₃ = 44.615 d ₃ = 2.02 n _d3 = 1.439 ν _d3 = 94.9
r ₄ = -54.988 d ₄ = 0.98 n _d4 = 1.755 ν _d4 = 52.3
r ₅ = 21.850 d ₅ = 2.54 n _d5 = 1.439 ν _d5 = 94.9
r ₆ = -18.869 d ₆ = 0.30
r ₇ = 38.263 d ₇ = 1.12 n _d7 = 1.773 ν _d7 = 49.6
r ₈ = 19.024 d ₈ = 3.40 n _d8 = 1.439 ν _d8 = 94.9
r ₉ = -15.078 d ₉ = 1.16 n _d9 = 1.673 ν _d9 = 38.2
r ₁₀ = -29.176 d ₁₀ = 0.30
r ₁₁ = 10.111 d ₁₁ = 4.80 n _d11 = 1.439 ν _d11 = 94.9
r ₁₂ = -16.352 d ₁₂ = 2.38 n _d12 = 1.673 ν _d12 = 38.2
r ₁₃ = -21.922 d ₁₃ = 1.04
r ₁₄ = -19.343 d ₁₄ = 1.68 n _d14 = 1.755 ν _d14 = 52.3
r ₁₅ = 16.276 d ₁₅ = 2.95
r ₁₆ = 10.724 d ₁₆ = 4.38 n _d16 = 1.673 ν _d16 = 38.2
r ₁₇ = -139.230 d ₁₇ = 2.32 n _d17 = 1.487 ν _d17 = 70.2
r ₁₈ = 6.443

FIG. 5 is a sectional view along the optical axis showing the optical configuration of the objective lens according to Example 3 of the present invention, and FIG. 6 is a diagram showing spherical aberration, astigmatism, coma aberration, and distortion of the objective lens shown in FIG. It is. The aberration diagram of FIG. 6 shows the light rays shown in FIG.
The objective lens of Example 3 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a negative refractive power. It consists of and.
The first lens group G1 includes, in order from the object side, a positive meniscus lens L11 having a concave surface directed toward the object side, and a cemented lens L12 of a biconvex lens L12 ₁ , a biconcave lens L12 _2, and a biconvex lens L12 ₃ . .
The second lens group G2, a cemented lens L21 of a negative meniscus lens L21 ₃ having a concave surface facing the negative meniscus lens L21 ₁ biconvex lens L21 ₂ and the object side with a convex surface on the object side, a biconvex lens L22 ₁ with the object It is composed of a cemented lens L22 of a negative meniscus lens L22 ₂ having a concave surface facing the side.
The third lens group G3 includes a biconcave lens L31, and a biconvex lens L32 ₁ and a cemented lens L32 of a biconcave lens L32 _2.

Next, numerical data of optical members constituting the objective lens of Example 3 are shown.
Numerical data 3 (Example 3)
r ₀ = ∞ (object surface) d ₀ = 10.00
r ₁ = -22.417 d ₁ = 3.17 n _d1 = 1.652 ν _d1 = 58.6
r ₂ = -8.789 d ₂ = 1.36
r ₃ = 52.297 d ₃ = 2.36 n _d3 = 1.439 ν _d3 = 94.9
r ₄ = −27.425 d ₄ = 1.31 n _d4 = 1.678 ν _d4 = 55.3
r ₅ = 21.332 d ₅ = 2.79 n _d5 = 1.439 ν _d5 = 94.9
r ₆ = -18.559 d ₆ = 0.30
r ₇ = 48.139 d ₇ = 1.10 n _d7 = 1.697 ν _d7 = 55.5
r ₈ = 14.333 d ₈ = 3.27 n _d8 = 1.439 ν _d8 = 94.9
r ₉ = -16.399 d ₉ = 1.54 n _d9 = 1.673 ν _d9 = 38.2
r ₁₀ = -26.360 d ₁₀ = 0.30
r ₁₁ = 10.546 d ₁₁ = 4.79 n _d11 = 1.439 ν _d11 = 94.9
r ₁₂ = -16.080 d ₁₂ = 2.42 n _d12 = 1.673 ν _d12 = 38.2
r ₁₃ = -21.417 d ₁₃ = 1.04
r ₁₄ = -19.067 d ₁₄ = 1.83 n _d14 = 1.729 ν _d14 = 54.7
r ₁₅ = 23.332 d ₁₅ = 2.68
r ₁₆ = 11.190 d ₁₆ = 4.40 n _d16 = 1.673 ν _d16 = 38.2
r ₁₇ = -911.649 d ₁₇ = 2.33 n _d17 = 1.516 ν _d17 = 64.1
r ₁₈ = 6.600

7 is a cross-sectional view along the optical axis showing the optical configuration of the objective lens according to Example 4 of the present invention. FIG. 8 is a diagram showing spherical aberration, astigmatism, coma aberration, and distortion of the objective lens shown in FIG. It is. Note that the aberration diagram of FIG. 8 shows the rays shown in FIG.
The objective lens of Example 4 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a negative refractive power. It consists of and.
The first lens group G1 includes, in order from the object side, a positive meniscus lens L11 having a concave surface directed toward the object side, and a cemented lens L12 of a biconvex lens L12 ₁ , a biconcave lens L12 _2, and a biconvex lens L12 ₃ . .
The second lens group G2, a cemented lens L21 of a negative meniscus lens L21 ₃ having a concave surface facing the negative meniscus lens L21 ₁ biconvex lens L21 ₂ and the object side with a convex surface on the object side, a biconvex lens L22 ₁ with the object And a cemented lens L22 with a negative meniscus lens L22 ₂ having a concave surface on the side.
The third lens group G3 includes a biconcave lens L31, and a biconvex lens L32 ₁ and a cemented lens L32 of a biconcave lens L32 _2.

Next, numerical data of optical members constituting the objective lens of Example 4 are shown.
Numerical data 4 (Example 4)
r ₀ = ∞ (object plane) d ₀ = 8.00
r ₁ = -13.325 d ₁ = 4.20 n _d1 = 1.773 ν _d1 = 49.6
r ₂ = -8.586 d ₂ = 1.36
r ₃ = 50.451 d ₃ = 2.48 n _d3 = 1.439 ν _d3 = 94.9
r ₄ = -18.136 d ₄ = 1.50 n _d4 = 1.652 ν _d4 = 58.6
r ₅ = 25.347 d ₅ = 3.05 n _d5 = 1.439 ν _d5 = 94.9
r ₆ = -13.226 d ₆ = 0.30
r ₇ = 75.418 d ₇ = 1.10 n _d7 = 1.603 ν _d7 = 60.6
r ₈ = 1.969 d ₈ = 2.76 n _d8 = 1.439 ν _d8 = 94.9
r ₉ = -13.738 d ₉ = 1.59 n _d9 = 1.673 ν _d9 = 38.2
r ₁₀ = -28.596 d ₁₀ = 0.30
r ₁₁ = 11.188 d ₁₁ = 4.68 n _d11 = 1.439 ν _d11 = 94.9
r ₁₂ = -16.284 d ₁₂ = 2.51 n _d12 = 1.673 ν _d12 = 38.2
r ₁₃ = -20.060 d ₁₃ = 1.02
r ₁₄ = -18.242 d ₁₄ = 2.22 n _d14 = 1.755 ν _d14 = 52.3
r ₁₅ = 32.713 d ₁₅ = 3.08
r ₁₆ = 12.623 d ₁₆ = 4.47 n _d16 = 1.673 ν _d16 = 38.2
r ₁₇ = −53.137 d ₁₇ = 2.36 n _d17 = 1.516 ν _d17 = 64.1
r ₁₈ = 7.086

表２

Next, the following table 1 and table 2 show conditional expression parameters and conditional expression corresponding values in each embodiment of the present invention. In Table 1, NA is the numerical aperture and β is the magnification.
Table 1

Table 2

The objective lens of the present invention configured as described above is used in a microscope and further in an optical device having a function as a microscope.
Then, the example of the optical apparatus provided with the objective lens of this invention is demonstrated next.
FIG. 9 is a schematic configuration diagram showing an example in which the objective lens of the present invention is used in a laser repair apparatus. For convenience of explanation, each optical element is shown in a simplified manner.
The laser repair apparatus of this example includes an observation illumination optical system 1, an imaging optical system 2, a display device 3, a processing irradiation optical system 4, a processing drive control means 5, and a processing position adjustment drive control means 6. And an autofocus means 7. On the optical path common to the observation illumination optical system 1, the imaging optical system 2, and the processing irradiation optical system 3, an objective lens 8 configured in the same manner as the objective lens of any one of the above-described embodiments of the present invention is provided. Has been placed. The observation illumination optical system 1 and the imaging optical system 2 have a function as a microscope.

The observation illumination optical system 1 includes an observation light source 11, an illumination lens 12, an optical path branching member 13 such as a half mirror, and an objective lens 8 on its optical path.
The imaging optical system 2 reflects on the optical path an imaging element 21 such as a CCD, an imaging lens 23, a half mirror or a wavelength necessary for observation, and other wavelengths (for example, a repair laser wavelength of 355 nm). Optical path branching member 24 such as a dichroic mirror that transmits, optical path branching member 71 such as a dichroic mirror that reflects the wavelength of infrared light (for example, 785 nm), and transmits other wavelengths, optical path branching member 13, and objective lens 8.
The display device 3 is configured by a TV monitor or the like connected to the image sensor 21 and can display an observation image captured by the image sensor.
The processing irradiation optical system 4 includes a processing light source 41, a slit member 42 for determining a light beam diameter from the light source 41, a processing illumination lens 43, an optical path branching member 24, and an optical path branching member 13 on the optical path. The objective lens 8 is provided.
The slit member 42 is configured to be able to be switched to a plurality of types of slits having different diameters on the optical axis of the processing irradiation optical system 4.
The processing drive control unit 5 includes an image processing unit 51 and a slit diameter adjustment drive control unit 52.
The image processing unit 51 converts image information captured by the image sensor 21 into predetermined numerical information. The slit diameter adjustment drive control unit 52 determines the beam diameter of the processing irradiation light source from the numerical information obtained via the image processing unit 51, and is not shown so that the determined size of the slit is positioned on the optical path. The slit member 42 is configured to be switched and driven via the driving device.
The processing position adjustment drive control unit 6 moves the position of the workpiece in a two-dimensional direction (for example, a direction parallel to and perpendicular to the paper surface) and a stage drive control unit 61 that controls the drive direction and drive amount of the stage 62. And a possible stage 62.
The autofocus means 7 includes an optical path branching member 71, an autofocus imaging lens 72, an autofocus light sensor 73, and an autofocus control unit 74.
The autofocus lens 72 forms an image of light from the objective lens 8 on the autofocus sensor 73.
The autofocus control unit 74 is necessary for the image formation state obtained via the autofocus light sensor 73 to be in focus based on the image formation information obtained via the autofocus light sensor 73. The movement amount of the stage 62 in the direction of the optical axis of the objective lens 8 (vertical direction on the paper surface) is calculated, and the stage 62 is moved based on the calculated movement amount.

When repairing an observation object such as a semiconductor IC with the laser repair apparatus of this example configured as described above, light is emitted from the observation light source 1, passes through the illumination lens 12, and is reflected by the half mirror 13. The observation object placed on the stage 62 through the objective lens 8 is illuminated with light. The light from the observation object passes through the objective lens 8, and the light transmitted through the half mirror 13 enters the dichroic mirror 71. Then, light necessary for observation passes through the dichroic mirror 71, enters the dichroic mirror 24, and the light reflected by the dichroic mirror 24 passes through the lens 23 and is imaged by the imaging device 21. Image information captured by the image sensor 21 is displayed on the TV monitor 3. While observing the image displayed on the TV monitor 3, the observer passes through the stage drive control unit 61 and the stage 62 so that the part requiring repair is positioned on the optical axis of the processing irradiation optical system 4. The position of the observation object is moved in a predetermined direction.
At this time, of the light from the objective lens 8 incident on the dichroic mirror 71, the wavelength of infrared light (for example, 785 nm) is reflected by the dichroic mirror 71, and is used for autofocus through the autofocus imaging lens 72. An image is formed on the optical sensor 73. The autofocus control unit 74 is necessary for the image formation state obtained via the autofocus light sensor 73 to be in focus based on the image formation information obtained via the autofocus light sensor 73. Then, the movement amount of the stage 62 in the optical axis direction (vertical direction on the paper surface) of the objective lens 8 is calculated, and the stage 62 is moved based on the calculated movement amount.

At this time, the image processing unit 51 converts the image information captured by the image sensor 3 into predetermined numerical information. The slit diameter adjustment drive control unit 52 determines the light beam diameter of the processing irradiation light source from the numerical information obtained through the image processing unit 51, and the slit 42 having the determined size is positioned on the optical path. The slit 42 is switched and driven through the omitted driving device.
Thereafter, a laser beam having a predetermined wavelength (for example, 355 nm) is emitted from the processing light source 41. The laser beam passes through the slit 42 with a light beam having a predetermined diameter. Then, the light that has passed through the illumination lens 43, the dichroic mirrors 24 and 71, and the half mirror 13 is irradiated to the object to be processed through the objective lens 8. The workpiece (observation object) in the portion irradiated with the laser light is removed via the laser light.

  At this time, according to the laser repair apparatus of this example, the objective lens 8 has the same configuration as that of any objective lens of this example. Can be easily performed. Moreover, the chromatic aberration is sufficiently corrected, and the imaging position of the observation wavelength during observation with the naked eye or the TV camera and the imaging position of the repair laser wavelength (for example, the fourth harmonic of Yag at 355 nm) during the defect repair. And an infrared imaging position in autofocus using an infrared region (for example, 785 nm) can be brought close to each other, and high-resolution observation and high-precision defect repair can be performed simultaneously.

  As described above, the objective lens of the present invention has the following features in addition to the configurations described in the claims.

(1) In order from the object side, a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a negative refractive power, and the following conditions An objective lens that satisfies the expressions (1) and (3).
0.3 <F / WD <2 (1)
0.6 <f2 / f1 <1.67 (3)
Where F is the focal length of the entire system at the d-line, WD is the working distance, f1 is the focal length of the first lens group at the d-line, and f2 is the focal length of the second lens group at the d-line.

(2) In order from the object side, a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a negative refractive power, and the following conditions When satisfying the formula (1) and including at least one cemented lens and the difference in refractive index at d-line is Δn in at least two of the glass materials constituting the cemented lens, the following condition is satisfied. An objective lens satisfying Expression (4).
0.3 <F / WD <2 (1)
0.17 <| Δn | (4)
However, F is the focal length of the whole system in d line, and WD is a working distance.

(3) In order from the object side, a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a negative refractive power, and the following conditions When satisfying the formula (1) and including at least one cemented lens and the difference in Abbe number at d-line is Δν in at least two of the glass materials constituting the cemented lens, the following condition is satisfied. An objective lens satisfying the expression (5).
0.3 <F / WD <2 (1)
42 <| Δν | (5)
However, F is the focal length of the whole system in d line, and WD is a working distance.

(4) The following conditional expression (4) is satisfied when the difference in refractive index at d-line is Δn in at least two of the glass materials that include at least one cemented lens and constitute the cemented lens. The objective lens according to (1), wherein
0.17 <| Δn | (4)

(5) The following conditional expression (5) is satisfied when the difference of the Abbe number in d-line is Δν in at least two of the glass materials constituting the cemented lens including at least one cemented lens. The objective lens according to (1) or (2), characterized in that:
42 <| Δν | (5)

(6) When including at least one cemented lens and at least two of the glass materials constituting the cemented lens, the difference in refractive index at d-line is Δn and the difference in Abbe number at d-line is Δν The objective lens according to (1), wherein the following conditional expressions (4) and (5) are satisfied.
0.17 <| Δn | (4)
42 <| Δν | (5)

(1) An optical device including the objective lens according to any one of (1) to (5).

  The objective lens of the present invention is useful in the field of a microscope used in a laser repair apparatus for repairing a defective portion generated in observation / inspection of a semiconductor IC or a liquid crystal panel.

It is sectional drawing which follows the optical axis which shows the optical structure of the objective lens concerning Example 1 of this invention. It is a figure which shows the spherical aberration, astigmatism, coma aberration, and distortion aberration of the objective lens shown in FIG. It is sectional drawing which follows the optical axis which shows the optical structure of the objective lens concerning Example 2 of this invention. It is a figure which shows the spherical aberration, astigmatism, coma aberration, and distortion aberration of the objective lens shown in FIG. It is sectional drawing which follows the optical axis which shows the optical structure of the objective lens concerning Example 3 of this invention. It is a figure which shows the spherical aberration of the objective lens shown in FIG. 5, astigmatism, a coma aberration, and a distortion aberration. It is sectional drawing which follows the optical axis which shows the optical structure of the objective lens concerning Example 4 of this invention. It is a figure which shows the spherical aberration of the objective lens shown in FIG. 7, astigmatism, a coma aberration, and a distortion aberration. It is a schematic block diagram which shows the example which used the objective lens of this invention for the laser repair apparatus.

Explanation of symbols

G1 First lens group G2 having a positive refractive power Second lens group G3 having a positive refractive power Third lens group L11 having a negative refractive power Positive meniscus lens L12 having a concave surface facing the object side Joint lens L12 ₁ both Convex lens L12 ₂ Biconcave lens L12 ₃ Biconvex lens L21 Joint lens L21 ₁ Negative meniscus lens L21 with convex surface facing the object side ₂ Biconvex lens L21 ₃ Negative meniscus lens L22 with concave surface facing the object side Joint lens L22 ₁ Biconvex lens L22 ₂ Object Negative meniscus lens L31 with a concave surface facing side Biconcave lens L32 Joint lens L32 ₁ Biconvex lens L32 ₂ Biconcave lens 1 Observation illumination optical system 2 Imaging optical system 3 Display device 4 Processing irradiation optical system 5 Processing drive control means 6 Processing Position adjustment drive control means 7 Auto focus means 8 Objective lens 11 Light source for observation 12 Illumination lens 3 the optical path branching member (half-mirror)
21 Image sensor 23 Imaging lens 24 Optical path branching member (dichroic mirror or half mirror)
41 processing light source 42 slit member 43 processing illumination lens 51 image processing unit 52 slit diameter adjustment drive control unit 61 stage drive control unit 62 stage 71 optical path branching member (dichroic mirror)
72 Autofocus imaging lens 73 Autofocus light sensor 74 Autofocus controller

Claims (5)

In order from the object side, the lens unit includes a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a negative refractive power. The following conditional expression (1 ) And objective lens satisfying (2).
0.3 <F / WD <2 (1)
0.5 <F / | f3 | <1.5 (2)
Where F is the focal length of the entire system at the d-line, WD is the working distance, and f3 is the focal length of the third lens group at the d-line. The objective lens according to claim 1, wherein the following conditional expression (3) is satisfied.
0.6 <f2 / f1 <1.67 (3)
Here, f1 is the focal length of the first lens group at the d-line, and f2 is the focal length of the second lens group at the d-line. In at least two glass materials including at least one cemented lens and constituting the cemented lens, when the refractive index difference at d-line is Δn and the Abbe number difference at d-line is Δν, the following: The objective lens according to claim 1, wherein the conditional expressions (4) and (5) are satisfied.
0.17 <| Δn | (4)
42 <| Δν | (5) It includes at least one cemented lens, and the cemented lens includes a convex lens and a meniscus lens, and the convex lens satisfies the following conditional expression (6) when anomalous dispersion in g-line is Δθgd: The objective lens according to claim 1.
0.03 <Δθgd (6) An optical apparatus comprising the objective lens according to claim 1.

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