JPH10221612A - Focussing operation supporting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely execute a focussing operation by vibrating a sample in a horizontal direction a little and permitting a mark for supporting the focussing operation, which is projected on the sample, to be clear. SOLUTION: A microscope 1 is supporsed to be an optical equipment. Then, A stage 10 for placing the sample S, which is positioned under an objective lens 2, is vibrated in the horizontal direction (the 'horizontal direction' in this case is used to mean the one as against a case where the optical axis of an observation optical path in a microscope is adopted as vertical) a little by driving power mechanism. Thus, the sample S is vibrated a little in the horizontal direction. Then, even when the surface constitutes the rough one, one-color uniformity is obtained by appearance by afterimage hardening so that the effect of high contrast with the mark is aimed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for assisting a focusing operation, and more particularly, to a method for sharpening a focusing operation assisting mark projected on a sample when performing a focusing operation in an optical apparatus. .

[0002]

2. Description of the Related Art For example, the length of a sample in the Z-axis direction is measured with an optical instrument such as an optical measuring instrument, a microscope, a non-contact level difference measuring instrument, an optical three-dimensional measuring instrument, a film thickness measuring instrument, and a thickness measuring instrument. It is known to project a mark such as a target mark on a sample in order to facilitate a focus determination when performing a focus operation visually, as in the case where the focus operation is performed.

[0003]

In this case, there is no problem if the contrast between the sample and the projected mark is high,
For example, the sample has a high reflectance on the surface of ceramics, etc.
With a rough surface, there is a problem that the contrast of the mark projected due to irregular reflection is insufficient, it is difficult to visually determine the focus, and it is not possible to focus accurately.

[0004]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of providing a focusing operation support method which solves the above-mentioned problems of the prior art, and performs a focusing operation in an optical apparatus. In this case, the sample is finely vibrated in a horizontal direction to sharpen a focus operation support mark projected on the sample (first invention).

In other words, according to the present invention, the sample vibrates slightly in the horizontal direction, so that even if the surface has a rough surface,
Due to the afterimage effect, the color looks uniform and uniform, and only the mark can be clearly recognized as an image.

Further, the observation light beam may be optically shaken so that the sample to be observed slightly vibrates in the horizontal direction, and in this case, the same effect as described above is produced (the second invention). ). Here, "optically shake the observation light beam" is used to mean a state in which the direction of the observation light beam is repeatedly changed between a normal direction and a direction deflected in a minute range. .

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIGS. 1 to 4 are views showing an embodiment of the first invention. Here, the microscope 1 is assumed as the optical device (see FIG. 1).
The stage 10 on which the sample S located below the objective lens 2 is mounted is moved in the horizontal direction by a power mechanism (in this specification, the “horizontal direction” refers to the horizontal direction with respect to the case where the optical axis of the observation optical path of the microscope is vertical. It is used in the meaning.)

[0008] In the present invention, by vibrating the sample in the horizontal direction, even if the surface has a rough surface,
The aim is to achieve an effect in which the afterimage effect makes the image look uniform in one color and the contrast with the mark increases. In this case, in order to obtain such an effect within a range that does not hinder practical use,
Experiments have confirmed that the sample must be slightly vibrated in the horizontal direction at the next maximum moving speed. Maximum moving speed: 0.1mm / S

FIGS. 2 and 3 show an example of a mechanism for microvibrating the stage 10 in the microscope of FIG.
Here, the stage 10 is finely vibrated by reciprocating along the guides 11. The stage 10 is reciprocally movable between the pair of guides 11, 11 by the rollers 13, 13 rotatably provided at both ends thereof being held between the rail grooves 12, 12 of the pair of guides 11, 11 and rolling. Is held. On the other hand, the stage 10 is constantly urged toward the other end by the coil spring 14 abutting on one end, and is pressed by a predetermined amount by the rotation of the eccentric cam 16 by the eccentric cam 16 rotated by the motor 15 coming into contact with the other end. Then, it reciprocates along the guides 11 and 11.

The means for pressing the stage 10 is not limited to the above-described eccentric cam 16, but may be, for example, a plunger 18 reciprocating in a solenoid 17 as shown in FIG. 4 or other means. Of course.

FIGS. 5 and 6 show an embodiment of the second invention. In the present invention, the observation light beam is optically shaken so that the sample to be observed is slightly vibrated in the horizontal direction, in contrast to the first invention in which the sample itself is finely vibrated physically. In (2), a means for optically shaking the observation light beam is provided by interposing a mirror that slightly vibrates near the exit pupil of the objective lens in the observation optical path.

Here, it is assumed that an infinity-correction microscope is used as the optical apparatus, and FIG. 5 is a diagram showing the optical system. In the drawing, reference numeral A denotes an observation optical path for the observer to observe the sample. The observation light beam of the sample on the stage 20 passes through the objective lens 21 and is reflected and deflected by the mirror 22. Is reflected and deflected, passes through the imaging lens 30, enters the eyepiece lens 31, and is observed by an observer.

On the other hand, reference numeral B in the drawing denotes an illumination light path for illuminating the sample and projecting a target mark on the sample. The illumination light flux from the light source 34 passes through the target mark plate 33, and then passes through the projection lens 32 and the projection lens 32. Semi-transparent mirror 29
And is projected onto the observation optical path A. The illumination light beam projected on the observation optical path A is also reflected and deflected by the mirror 22, enters the objective lens 21, and projects the target mark on the sample.

In the above optical system, the observation light beam is optically shaken by slightly vibrating the mirror 22.
FIG. 6 shows an example of a mechanism for finely oscillating the mirror 22 in this case. Here, a holder 23 holding the mirror 22 is pivotally supported on a receiving seat 24 fixed to the microscope with a shaft 24 so as to be swingable, and one side of the holder 22 is urged by a coil spring 26 in a pulling direction. Eccentric cam 28 whose other side is rotated by motor 27
, The mirror 22 is pressed by the rotation of the eccentric cam 28 and swings about the shaft 24 to cause slight vibration. Therefore, the deflection direction of the observation light beam reflected by the light beam repeatedly changes between a normal direction (90 degrees in this embodiment) and a direction in which the direction is increased or decreased in a minute range.

FIG. 7 is a diagram showing an optical system of an infinity corrected microscope according to a different embodiment of the second invention. In this embodiment, a pair of prisms having the same refractive power are arranged in the observation optical path in the vicinity of the exit pupil of the objective lens so as to be interposed between the upper and lower backs, and these are rotated in opposite directions, thereby obtaining the observation light flux. Is a means for optically shaking linearly.

In the drawing, reference numeral A denotes an observation optical path for an observer to observe the sample. The observation light beam of the sample on the stage 20 passes through the objective lens 21 and then passes through a pair of prisms 36, 3
7 and further pass through the semi-transmissive mirror 35 and the imaging lens 30 to enter the eyepiece 31 for observation by an observer.

On the other hand, reference numeral B in the figure denotes an illumination light path for illuminating the sample and projecting a target mark on the sample. The illumination light beam from the light source 34 passes through the target mark plate 33 and then passes through the lens 32. Then, the light is further reflected and deflected by the semi-transmissive mirror 35 and is projected on the observation optical path A. The illumination light beam projected on the observation optical path A passes through the pair of prisms 36 and 37, enters the objective lens 21, and projects a target mark on the sample.

The pair of prisms 36 and 37 have the same refracting power, and are arranged back-to-back and rotated in opposite directions (a rotation mechanism is not shown). Therefore, the observation light flux is deflected in different directions depending on the mutual positions of these prisms 36 and 37 during rotation, and consequently is shaken linearly. When the positions of the prisms 36 and 37 are set to 0 ° in FIG. 8, FIG.
0 °, and FIG. 9 shows a state of rotation by 180 °.

[0019]

According to the present invention having the above configuration,
Even if the surface of the sample forms a rough surface and the contrast is low,
Due to the afterimage effect due to the slight vibration in the horizontal direction, the image appears to be a uniform color in appearance, and only the mark can be clearly recognized as an image, so that there is an effect that a reliable focusing operation can be performed.

[0020] A first method in which the sample itself is physically vibrated finely.
In contrast to the invention, according to the second invention in which the observation light beam is optically shaken so that the sample to be observed slightly vibrates in the horizontal direction, even if the sample cannot be finely vibrated for some reason, the same as above. The effect can be obtained.

In the second invention, in this case, even if the sample vibrates, the mark appears to be stationary to the observer. That is, as shown in FIG. 5, the light beam is deflected by a mirror 22 installed near the exit pupil of the objective lens 21, and the mark is projected to a position off the optical axis on the sample. Are again deflected and the mark always appears stationary because it is imaged on the original optical axis. on the other hand,
When the sample is deflected by the mirror, it forms an image at a position off the optical axis, so that the sample appears to be vibrating.

[Brief description of the drawings]

FIG. 1 is a side view of a microscope embodying the first invention.

FIG. 2 is a plan view of the stage part with a part cut away;

FIG. 3 is a front view of the stage part with a part cut away;

FIG. 4 is a partially cutaway plan view of an embodiment having a different stage portion.

FIG. 5 is a configuration diagram of an optical system of a microscope embodying the second invention.

FIG. 6 is a side view of a mirror part according to the first embodiment;

FIG. 7 is a configuration diagram of an optical system of a microscope according to another embodiment.

FIG. 8 is a configuration diagram of a main part of the optical system.

FIG. 9 is a configuration diagram of a main part of the optical system according to the first embodiment;

[Explanation of symbols]

 10 Stage 22 Mirror 36 Prism 37 Prism A Observation optical path

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/027 H01L 21/30 526Z

Claims (5)

[Claims] When performing a focusing operation in an optical apparatus, a focusing operation support mark projected on the sample is sharpened by slightly vibrating the sample in a horizontal direction. Method. 2. The focusing operation supporting method according to claim 1, wherein the stage on which the sample is placed is slightly vibrated in the horizontal direction. 3. A focusing operation assisted by projecting an observation light beam on an optical device such that the observation light beam is optically shaken so that an observed sample vibrates in an apparently horizontal direction when performing a focusing operation in an optical apparatus. Focusing operation support method characterized by sharpening a mark for use. 4. The focusing operation supporting method according to claim 3, wherein a mirror that vibrates minutely in the observation optical path is interposed to optically shake the observation light beam. 5. The focusing operation supporting method according to claim 3, wherein a rotating prism is interposed in the observation optical path to optically shake the observation light beam.