JPH0942928A - Scanning dimension measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely measure two-dimensional dimensions with the use of an inexpensive and small-sized galvanomirror for deflecting a received laser beam, by locating an article to be measured between the galvanomirror and a light incident position detecting means. SOLUTION: When a scanning beam 111 is oscillated so as to scan an article 112 to be measured, which is located between a collimator lens 102 and a PSD (position sensitive device), by means of a two-dimensional galvanomirror 101, the scanning beam 111 which is not blocked by the article 112 to be measured can reach a detecting surface of the SPD 103, and X-axial and Y-axial data are delivered from the PSD 103. These X-axial and Y-axial data are amplified by amplifiers 104, 107, and are then converted by A-D converters 105, 106 into digital data which are then computed by a microcomputer 106. With this arrangement, dimensions of respective parts of the projected image shape 113 of the article 112 onto the PSD 103 can be measured. Further, a projected image area can be obtained from the dimensions of the respective parts thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring an object by scanning an object to be measured with a laser beam.

[0002]

2. Description of the Related Art FIG. 15 is a diagram showing a configuration of a conventional scanning type dimension measuring apparatus, which is described as a conventional example in Japanese Patent Laid-Open No. 6-3116. In FIG. 15, 30
Reference numerals 0 to 305 are elements constituting a "scanning type dimension measuring device", 300 is a light emitting means of a semiconductor laser, 301 is a front lens, 302 is a scanning mirror of a polygon mirror, 303 is a collimator lens, 304 is a condenser lens, 305 Is a light receiving element. 306 is a laser beam, and 307 is an object to be measured.

The laser light 306 sent from the light emitting means 300 to the scanning mirror 2 through the front mirror 301 becomes scanning light parallel to the optical axis of the collimator lens 303 due to the rotation of the scanning mirror 2 and the refraction of the collimator lens 3. To be done.

As the collimator lens 303 arranged so that the reflecting surface of the scanning mirror 302 becomes the focal point, what is generally called an fθ lens is used.
By scanning the scanning mirror 2 at a constant speed, the scanning light is scanned at a constant speed in the direction orthogonal to the optical axis.

In the above structure, the collimator lens 3
If the object to be measured 307 is arranged between the measuring lens 03 and the condensing lens 304, the incidence of the scanning light on the light receiving element 305 is blocked for a time corresponding to the dimension of the object to be measured 307. The dimension D of the object to be measured 307 can be measured from the product of the time when the scanning light is blocked by the object 307 and the scanning speed.

[0006]

In the above-mentioned conventional example, a polygon mirror or an expensive f.theta. Lens must be used. Further, since the polygon mirror also needs to be accurately rotated at a constant speed, there is a problem that the device becomes expensive as in the case of the fθ lens due to the devise of the servo motor and its drive circuit.

Further, in the conventional example, since the laser beam is used for one-dimensional scanning, only the one-dimensional dimension can be measured as it is. Therefore, for example, when measuring the shape of a hole, it is necessary to separately provide a means for accurately moving the object to be measured. To perform this movement automatically, an expensive and large XY
A stage must be prepared, and there is a problem that the entire system becomes expensive and large-sized.

The present invention has been made in order to solve such a problem, and a first object thereof is to provide an inexpensive and compact scanning type dimension measuring device, and a scanning type capable of measuring two-dimensional dimensions. A second object is to provide a measuring device.

[0009]

In order to achieve the first object, the present invention provides a scanning type dimension measuring device (1) to (1).
In order to achieve the first and second objects, the scanning-type dimension measuring apparatus is configured as in (4) and as in (3) and (4) below.

(1) A laser beam generating means, a galvano mirror for receiving and deflecting a laser beam from the laser beam generating means, and a light incident position detecting means for receiving the laser beam from the galvano mirror and detecting its incident position. A scanning-type dimension measuring apparatus, comprising: an object to be measured between the galvanometer mirror and the light incident position detecting means, and measuring the dimension of the object to be measured.

(2) The scanning size measuring apparatus according to (1), further comprising a collimator lens for collimating a laser beam deflected by a galvanometer mirror.

(3) The galvanometer mirror is a two-dimensional galvanometer mirror capable of secondary deflection, and the light incident position detecting means is 2
The scanning-type dimension measuring device according to (1) or (2), which is a two-dimensional light incident position detecting means capable of detecting a three-dimensional light incident position.

(4) The galvanometer mirror is formed on the semiconductor substrate.
A movable plate and a torsion bar that pivotally supports the movable plate with respect to the semiconductor substrate are integrally formed, a drive coil is provided at a peripheral portion of the movable plate, and a mirror is provided on the movable plate. The scanning size measuring apparatus according to any one of (1) to (3), wherein the drive coil is provided with a magnetic field generating means for applying a static magnetic field, and the mirror is driven by passing a current through the drive coil. .

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to its embodiments. Prior to the description of the embodiments, the main elements that can be used in the present invention will be described.

In the present invention, a galvanometer mirror is used as the scanning mirror, and a PSD (Position Sewing) is used as the light (spot) detecting element.
nsitive Device) is used. Galvanometer mirrors and PSDs suitable for the present invention will be sequentially described as related technology examples.

(Galvano Mirror) The applicant of the present invention relates to a galvano mirror manufactured by utilizing a semiconductor manufacturing process and operating according to the principle of operation of a galvanometer, and Japanese Patent Application No. 5-3.
No. 20524, Japanese Patent Application No. 6-327369, Japanese Patent Application No. 7-
Proposals such as No. 138081 are made.

The contents of the respective proposals will be briefly described. The contents of the above-mentioned Japanese Patent Application No. 5-320524 are as follows: a semiconductor substrate, a movable plate, and a torsion bar which pivotally supports the movable plate with respect to the semiconductor substrate. Are integrally formed, a drive coil is provided on the peripheral portion of the movable plate, a mirror is provided on the movable plate, and a magnetic field generating means for applying a static magnetic field to the drive coil is provided to supply a current to the drive coil. This is a galvanometer mirror that drives the mirror, and is the basic form of this type of electromagnetic actuator.

Further, the content of the above-mentioned Japanese Patent Application No. 6-327369 is to prevent the wiring pattern of the torsion bar portion from breaking due to repeated twisting motions of the torsion bar in the electromagnetic actuator such as the galvanometer mirror described above. The torsion bar itself is electrically conductive to make an electrical connection. Further, the content of Japanese Patent Application No. 7-138081 relates to measures against impact of this electromagnetic actuator, and it is a stopper that opposes at least one surface of the movable plate and prevents excessive displacement of the movable plate when a shock is applied. Is provided.

As described above, the content of Japanese Patent Application No. 5-320524 is a basic type, so that Examples 1 to 3 will be described below as related technical examples 1 to 3.

(Related Art Example 1) FIGS. 3 and 4 are views showing a configuration of a "galvano mirror" which is related art example 1. As shown in FIG. This related technology example operates on the same principle as a galvanometer like the related technology example 2 and the related technology example 3 described later. Note that the size is exaggerated in FIGS. 3 and 4 for the sake of clarity. 5, 7, and 8, which will be described later.
The same applies to FIGS. 9 and 10.

In FIGS. 3 and 4, the galvanometer mirror 1
Are flat upper and lower glass substrates 3 and 4 as upper and lower insulating substrates made of, for example, borosilicate glass on the upper and lower surfaces of the silicon substrate 2 which is a semiconductor substrate.
It has a three-layer structure in which The upper glass substrate 3 is laminated on the left and right ends (in FIG. 3) of the silicon substrate 2 so as to open the upper portion of the movable plate 5 described later.

The silicon substrate 2 has a flat plate-shaped movable plate 5 and a torsion bar 6 which pivotally supports the movable plate 5 at the center of the movable plate 5 so that the movable plate 5 can swing vertically with respect to the silicon substrate 2. And are integrally formed by anisotropic etching in the semiconductor manufacturing process. Therefore, the movable plate 5
The torsion bar 6 is also made of the same material as the silicon substrate 2. A movable plate 5 is provided on an upper peripheral portion of the movable plate 5.
A plane coil 7 made of a copper thin film for supplying a driving current for driving and a detecting current for detecting a displacement angle superimposed on the driving current is provided by being covered with an insulating film. The detection current is for detecting the displacement of the movable plate 5 based on the mutual inductance with the detection coils 12A and 12B provided on the lower glass substrate 4 as described later.

Here, the coil has a Joule heat loss due to the resistance component, and a thin film coil having a large resistance is used as the plane coil 7.
Since the driving force is limited due to heat generation when mounted in high density, the plane coil 7 is formed by a known electroformed coil method by electrolytic plating in a related art example. In the electroformed coil method, a thin nickel layer is formed on a substrate by sputtering, copper electroplating is performed on the nickel layer to form a copper layer, and the copper layer and the nickel layer are removed except for the portion corresponding to the coil. By removing it, a thin-film planar coil consisting of a copper layer and a nickel layer is formed. It has the characteristic that the thin-film coil can be mounted with low resistance and high density, and it is effective for downsizing and thinning of micro magnetic devices. . In addition, a mirror 8 is provided at the center of the upper surface of the movable plate 5 surrounded by the plane coil 7.
Are formed by aluminum vapor deposition. Further, a pair of electrode terminals 9, 9 electrically connected to the planar coil 7 via the portion of the torsion bar 6 are provided on the lateral upper surface of the torsion bar 6 of the silicon substrate 2. , 9 are formed on the silicon substrate 2 at the same time as the plane coil 7 by the electroformed coil method.

Magnetic fields are applied to the left and right sides (in FIG. 3) of the upper and lower glass substrates 3 and 4 (in FIG. 3) on the flat coil 7 portion on the opposite side of the movable plate 5 parallel to the axial direction of the torsion bar 6. Paired circular permanent magnets 10A, 1
0B, 11A, and 11B are provided. The upper and lower three permanent magnets 10A and 10B, which are paired with each other, are provided so that the upper and lower polarities are the same, for example, as shown in FIG. 4, the lower side is the N pole and the upper side is the S pole. There is. In addition, the other three permanent magnets 11A and 11B each have the same upper and lower polarities, for example, as shown in FIG.
The lower side is an S pole and the upper side is an N pole. The permanent magnets 10A and 11A on the upper glass substrate 3 side and the permanent magnets 10B and 11B on the lower glass substrate 4 side are provided so that the upper and lower polarities thereof are opposite to each other.

Further, as described above, the lower glass substrate 4
A pair of coils 12A and 12B, which are arranged so as to be electromagnetically coupled to the planar coil 7 and whose ends are electrically connected to the paired electrode terminals 13 and 14, respectively, are provided on the lower surface of (1) by patterning ( In addition, in FIG. 3, one dashed line is schematically shown, but in reality, a plurality of windings are provided. The detection coils 12A and 12B are arranged at symmetrical positions with respect to the torsion bar 6 to detect the displacement angle of the movable plate 5, and the flat coil 7 based on the detection current passed through the flat coil 7 in a manner superimposed on the drive current. Since the mutual inductance between the detecting coil 12A and the detecting coil 12A and 12B changes so that one of them approaches and increases and the other of them separates and decreases by the angular displacement of the movable plate 5,
For example, the displacement angle of the movable plate 5 can be detected by differentially detecting the change in the voltage signal output based on the mutual inductance.

Next, the operation will be described.

For example, one electrode terminal 9 is used as a + pole and the other electrode terminal 9 is used as a pole, and a current is passed through the planar coil 7. A magnetic field is formed on both sides of the movable plate 5 by the permanent magnets 10A and 10B and the permanent magnets 11A and 11B in a direction crossing the plane coil 7 along the plane of the movable plate 5 as shown by an arrow B in FIG. Therefore, when a current flows through the plane coil 7 in the magnetic field, the plane coil 7, in other words, both ends of the movable plate 5, are moved in accordance with the current density and the magnetic flux density of the plane coil 7.
The force F acts in the direction (indicated by the arrow F in FIG. 5) according to the Fleming's left-hand rule of current, magnetic flux density, and force, and this force is obtained from the Lorentz force.

This force F is calculated by the following equation (1), where i is the current density flowing in the planar coil 7 and B is the magnetic flux density of the upper and lower permanent magnets.

F = i × B (1) Actually, it depends on the number of turns n of the plane coil 7 and the coil length w (shown in FIG. 5) on which the force F acts. Like

F = nw (i × B) (2) On the other hand, as the movable plate 5 rotates, the torsion bar 6
The relationship between the spring reaction force F ′ of the torsion bar 6 and the displacement angle φ of the movable plate 5 caused by this is expressed by the following equation (3).

Θ = (Mx / GIp) = F′L / 8.5 × 10 ⁹ r ⁴ ) × l ₁ (3) where Mx is a torsional moment, G is a lateral elastic coefficient, and Ip
Is the polar moment of inertia. Also, L, l ₁ , r
Are respectively the distance from the central axis of the torsion bar to the force point, the length of the torsion bar, and the radius of the torsion bar, which are shown in FIG.

Then, the movable plate 5 is rotated to a position where the force F and the spring reaction force F'balance. Therefore, by substituting the F in the equation (2) into the F ′ in the equation (3), it is understood that the displacement angle φ of the movable plate 5 is proportional to the current i flowing in the plane coil 7.

Therefore, the displacement angle φ of the movable plate 5 can be controlled by controlling the current flowing through the plane coil 7, so that, for example, the light of the mirror 8 is reflected in a plane perpendicular to the axis of the torsion bar 6. The axial direction can be freely controlled, and if the displacement angle is continuously changed, the monitored object can be scanned one-dimensionally.

When the displacement angle φ of the optical axis of the mirror 8 is controlled, the plane coil 7 is superposed on the drive current and is used for detection for displacement angle detection at a frequency of at least 100 times the drive current frequency. Apply current. Then, based on this detection current, an induced voltage due to mutual inductance between the flat coil 7 and the detection coils 12A and 12B provided on the lower glass substrate 5 is generated in each of the detection coils 12A and 12B. The induced voltages generated in the detection coils 12A and 12B are equal because the distance between the detection coils 12A and 12B and the corresponding planar coil 7 is equal when the movable plate 5, in other words, the mirror 8 is in the horizontal position. The difference is zero. When the movable plate 5 is rotated about the torsion bar 6 by the driving force described above, the one detection coil 12A is rotated.
(Or 12B), the induced voltage increases due to the increase in mutual inductance, and the other detection coil 12B
(Or 12A), the induced voltage is lowered due to the reduction of mutual inductance. Therefore, the detection coil 12
The induced voltage generated in A and 12B changes according to the displacement of the mirror 8, and the optical axis displacement angle φ of the mirror 8 can be detected by detecting this induced voltage.

Then, for example, as shown in FIG. 6, a power source is connected to a bridge circuit configured by providing two resistors in addition to the detection coils 12A and 12B, and a midpoint between the detection coils 12A and 12B is set. The output of the differential amplifier according to the voltage difference between the two midpoints is fed to the drive system of the movable plate 5 by using a circuit configured by providing a differential amplifier having a voltage between the midpoint of the two resistors as an input. By moving back and controlling the drive current, the optical axis displacement angle φ of the mirror 8 can be accurately controlled.

As described above, in the related art example,
Since the movable part including the mirror can be made compact and lightweight, the optical axis direction of the mirror can be changed at high speed, and the monitoring target can be scanned at high speed. Further, since the movable plate, the torsion bar, and the mirror, which are the main parts, can be formed from the same semiconductor substrate using the semiconductor element manufacturing process, cost reduction due to mass production can be expected.

(Related Art Example 2) FIG. 7 is a diagram showing a configuration of a "galvano mirror" which is related art example 2. As shown in FIG. The related art example 1 described above is one in which the optical axis direction is shaken in one dimension. However, in this related art example, two torsion bars are provided so as to be orthogonal to each other so that the torsion bar can be shaken in two dimensions. It is an example of a galvanometer mirror. The same elements as those of the related art example 1 are designated by the same reference numerals.

In FIG. 7, a galvano mirror 21 of the related art example has an upper and lower glass substrate as upper and lower insulating substrates made of borosilicate glass on the upper and lower surfaces of a silicon substrate 2 which is a semiconductor substrate, respectively. A three-layer structure in which 3 and 4 are overlapped and joined as indicated by an arrow is shown. As shown in the figure, the upper and lower glass substrates 3 and 4 each have a structure in which rectangular recesses 3A and 4A formed by, for example, ultrasonic processing are provided in the central portions, and when bonded to the silicon substrate 2, In the upper glass substrate 3, the recessed portion 3A is located on the silicon substrate 2 side with the recessed portion on the lower side, and in the lower glass substrate 4, the recessed portion 4A is located on the silicon substrate 2 side in the same manner. To join. Thus, the swinging space of the movable plate 5 provided with the mirror 8 described later is secured and hermetically sealed.

The silicon substrate 2 is provided with a flat movable plate 5 composed of an outer movable plate 5A formed in a frame shape and an inner movable plate 5B axially supported inside the outer movable plate 5A. ing. The outer movable plate 5A is pivotally supported on the silicon substrate 2 by the first torsion bars 6A and 6A,
The inner movable plate 5B includes the first torsion bar 6
The second torsion bar 6 whose axial direction is orthogonal to A and 6A
B and 6B are pivotally supported inside the outer movable plate 5A. Movable plates 5A, 5B and first and second torsion bars 6
A and 6B are integrally formed on the silicon substrate 2 by anisotropic etching, and are made of the same material as the silicon substrate 2.

On the upper surface of the outer movable plate 5A, a pair of outer electrode terminals 9A, 9A formed on the upper surface of the silicon substrate 2 are formed.
A flat coil 7A (both of which has a plurality of turns on the movable plate 5A is schematically shown by a single line in the drawing) whose both ends are electrically connected to each other through one of the first torsion bars 6A It is provided so as to be covered with an insulating layer. Further, on the upper surface of the inner movable plate 5B, a pair of inner electrode terminals 9B, 9B formed on the silicon substrate 2 is passed from the one second torsion bar 6B through the outer movable plate 5A portion to the first torsion bar. The flat coil 7B (which is schematically shown by a single line in the drawing, but has a plurality of turns on the inner movable plate 5B as well as the outer movable plate 5A) electrically connected to each other via the other side of 6A is insulated. It is provided covered with a layer. These plane coils 7A and 7B are formed by the known electroplating coil method by electrolytic plating as in the case of the related art example 1. The outer and inner electrode terminals 9A and 9B are formed on the silicon substrate 2 at the same time as the plane coils 7A and 7B by the electroformed coil method. At the center of the inner movable plate 5B surrounded by the plane coil 7B, a mirror 8 is formed by aluminum vapor deposition.

On the upper and lower glass substrates 3 and 4, eight disk-shaped permanent magnets 1 each consisting of two pairs are provided.
0A to 13A and 10B to 13B are arranged as illustrated. The permanent magnets 10A and 11A facing each other on the upper glass substrate 3 are the permanent magnets 10 on the lower glass substrate 4.
B and 11B act on the plane coil 7A of the outer movable plate 5A by a magnetic field to drive the outer movable plate 5A by interaction with a drive current flowing in the plane coil 7A. The permanent magnets 12A and 13A facing each other on the substrate 3 are the permanent magnets 1 on the lower glass substrate 4.
2B and 13B are for rotating the inner movable plate 5B by interacting with a driving current flowing through the planar coil 7B by applying a magnetic field to the planar coil 7B of the inner movable plate 5B. The upper and lower polarities of the permanent magnets 10A and 11A facing each other are opposite to each other.
When the upper surface of A is the S pole, the upper surface of the permanent magnet 11A is provided so as to be the N pole, and the magnetic flux thereof is arranged so as to cross the plane coil portion of the movable plate 5 in parallel.
Other permanent magnets 12A and 13 facing each other
A, permanent magnets 10B and 11B and permanent magnets 12B and 13
The same applies to B. Furthermore, the corresponding permanent magnets 1 in the vertical direction
The relationship between 0A and 10B is such that the upper and lower polarities are the same, for example, when the upper surface of the permanent magnet 10A is the S pole, the upper surface of the permanent magnet 10B is also the S pole. Other upper and lower corresponding permanent magnets 11A and 11B, permanent magnets 12A and 12
The same applies to B and the permanent magnets 13A and 13B, whereby the forces act in opposite directions at both ends of the movable body 5.

Then, on the lower surface of the lower glass substrate 4, the detection coils 15A, 15B and 16A, 16B arranged so as to be electromagnetically coupled to the above-mentioned plane coils 7A, 7B, respectively.
Are provided by patterning. Detection coil 15
A and 15B are provided at symmetrical positions with respect to the first torsion bar 6A, and the detection coils 16A and 16B are provided at symmetrical positions with respect to the second torsion bar 6B and are paired with each other. Then, the pair of detection coils 15A, 1
Reference numeral 5B is for detecting the displacement angle of the outer movable plate 5A, and the mutual inductance between the flat coil 7A and the detection coils 15A and 15B based on the detection current which is superposed on the drive current in the flat coil 7A is detected by the outer movable plate. It is changed by the angular displacement of 5 A, and an electric signal corresponding to this change is output. The displacement angle of the outer movable plate 5A can be detected from this electric signal.
The pair of detection coils 16A and 16B similarly detect the displacement angle of the inner movable plate 5B.

Next, the operation will be described.

When a drive current is applied to the plane coil 7A of the outer movable plate 5A, the outer movable plate 5A rotates about the first torsion bars 6A, 6A as a fulcrum in accordance with the current direction, and at this time, the inner movable plate 5B. Also rotates integrally with the outer movable plate 5A.
In this case, the mirror 8 moves in the same manner as the related art example 1. On the other hand, when a drive current is applied to the plane coil 7B of the inner movable plate 5B, the inner movable plate 5B is moved to the second movable torsion bar 6B, 6B relative to the outer movable plate 5A in the direction perpendicular to the rotating direction of the outer movable plate 5A. Rotate around as a fulcrum. Therefore, for example, by controlling the drive current of the plane coil 7A, the outer movable plate 5
After rotating A for one cycle, the drive current of the plane coil 7B is controlled so that the inner movable plate 5B is displaced by a certain angle, and if this operation is repeated cyclically, the optical axis of the mirror 8 is changed to two.
It can be swung in two dimensions and the monitored object can be scanned in two dimensions.

When glass is present above the mirror 8 as in the case of the related art, it is advisable to coat the glass surface with an antireflection film or the like.

On the other hand, the plane coil 7A and the plane coil 7B
If the detection current is passed by superimposing it on each drive current flowing in
Due to the mutual inductance between the detection coils 15A and 15B and the plane coil 7A and the mutual inductance between the detection coils 16A and 16B and the plane coil 7B, the displacement of the outer movable plate 5A is performed through a circuit similar to that of FIG. Can be detected by the differential output of the detection coils 15A and 15B, and can be detected by the differential output of the displacement detection coils 16A and 16B of the inner movable plate 5B. This differential output can be detected by the outer movable plate 5A and the inner side. By feeding back to each drive system of the movable plate 5B, the outer movable plate 5A and the inner movable plate 5B.
It is possible to accurately control the displacement of. Needless to say, in the case of the biaxial galvanometer mirror of the related art example, two circuits similar to those shown in FIG. 4 are provided for the outer movable plate displacement detection and the inner movable plate displacement detection.

According to the structure of the related art example 2, in addition to the same effect as the related art example 1, the monitoring target can be two-dimensionally scanned, and the scanning area is the one axis of the related art example 1. Can be increased compared to. In addition, the swinging space of the movable plate 5 is defined by the upper and lower glass substrates 3 and 4 and the surrounding silicon substrate 2.
Since the space is hermetically closed by means of, the air resistance to the rotating operation of the movable plate 5 is eliminated by bringing the closed space into a vacuum state, and the responsiveness of the movable plates 5A and 5B is improved.

Further, when the drive current flowing through the plane coils 7A and 7B is increased to set the displacement amount of the movable plates 5A and 5B large, the sealed movable plate swing space is not made to be a vacuum, but helium and argon are used. It is desirable to enclose an inert gas such as helium, and helium having particularly good thermal conductivity is preferable. This is because when the amount of current flowing through the planar coil 7 is increased, the amount of heat generated from the planar coil 7 increases, and heat radiation from the movable plate deteriorates when the movable plates 5A and 5B are in a vacuum state. As a result, the heat radiation from the movable plates 5A and 5B can be enhanced as compared with the vacuum state, and the heat effect can be reduced. By filling the inert gas, the responsiveness of the movable plates 5A and 5B will be slightly lower than that in the vacuum state.

It is needless to say that the upper and lower glass substrates of the above-mentioned related technology example 1 may have a structure similar to that of the related technology example 2 in which the movable plate portion is hermetically sealed.

(Related Technique Example 3) FIGS. 8, 9 and 10 show
It is a figure which shows the structure of the "galvano mirror" which is the example 3 of a related technology.

This related art example is similar to the related art example 2 in that
It is an example of an axis. The same elements as those of the related art example 2 are designated by the same reference numerals and the description thereof will be omitted.

The biaxial galvanometer mirror 31 of the related art example.
Has substantially the same configuration as the related art example 2 described above, but in the related art example, as shown in FIGS. 8 to 10, the upper and lower glass substrates 3 and 4 are different from those of the related art example 2. Differently, it is a flat plate without the concave portions 3A and 4A. The upper glass substrate 3 is provided with a rectangular opening 3a in the upper portion of the movable plate 5 according to the shape of the movable plate 5, and the upper portion of the mirror 8 is opened so that laser light can directly enter the mirror 8. Is done. Since the upper and lower glass substrates 3 and 4 are flat, the intermediate silicon substrate 2 is laminated on top of another silicon substrate to form a three-layer structure, and the movable plate 5 is formed on the intermediate layer to move the silicon substrate. A space for rotating the plate 5 is ensured.

Further, as shown by a broken line in FIG. 8, on the lower surface of the lower glass substrate 4, the detection coils 15A and 15B for detecting the displacement of the outer movable plate 5A and the detection coil 16A for detecting the displacement of the inner movable plate 5B. , 16B is the corresponding planar coil 7
A and 7B are patterned and provided at positions where electromagnetic coupling is possible.

The operation and effect of this related art example having such a configuration are the same as those of related art example 2, and the description thereof will be omitted.

(Variation) In the related technology example 2, scanning is performed linearly, but depending on the object, scanning can be performed in a concentric circle shape, a spiral shape, or a Lissajous figure shape.

In each of the related art examples, the central portion of the movable plate is pivotally supported by the torsion bar. However, the present invention is not limited to this, and the end portion of the movable plate, for example, the right side portion of the movable plate 5 in FIG. 3 is pivotally supported. Can be implemented as a form, in this case 1 on the left side
Displacement angle is detected by providing a number of detection coils.

In each of the related art examples, the drive current and the detection current are passed through the plane coil provided on the movable plate. However, when the frequency of the drive current is as high as several kilohertz, the drive current is also used as the detection current. However, it is possible to adopt a form in which the detection currents are not superimposed.

In each related art example, the displacement angle is detected by the difference between the outputs of the two detection coils, but one detection coil may be provided and the displacement angle may be detected by the output. .

(PSD) PSD is a light spot position detection sensor utilizing the surface resistance of a photodiode,
Since it is a non-divided type element different from a CCD or the like, continuous electric signals (X, Y coordinate signals) can be obtained, and position resolution and responsiveness are excellent.

As shown in FIG. 11, in this PSD, when light (spot) is incident, a charge proportional to the light energy is generated at the incident position. The generated charges pass through the surface resistance layer as photocurrent I _O and are output from the electrodes. Since the resistance layer has a uniform resistance value over the entire surface, the photocurrent I
O is divided and extracted in inverse proportion to the distance (resistance value) to the electrode, and the incident position is obtained from the equations (4) and (5) regardless of the incident light energy by the photocurrent ratio I1 / I2. be able to.

This PSD is divided into two types, one for one-dimensional position detection and the other for two-dimensional position detection. Further, the two-dimensional position detection is divided into a surface division type and a double side division type depending on the structure. The double-sided split type has excellent position detection error and resolution.
These PSDs are available from Hamamatsu Photonics KK, for example. The PSD of Hamamatsu Photonics KK will be described as related technologies 4 to 6 based on the pamphlet.

(Related Technique Example 4) FIG. 12 is an explanatory diagram of a one-dimensional SPD which is a related technique example 4. (A) shows a schematic structure and (b) shows an equivalent circuit. This PSD is C _j
Since it has a distribution circuit of R _p and R _p , this time constant is an element that determines the response waveform. However, by using the position signal integration circuit, it can be used for position detection of laser light having a pulse width of several hundred ps.

(Related Art Example 5) FIG. 13 shows a surface division type PS.
In the explanatory view of D, (a) shows a schematic configuration and (b) shows an equivalent circuit.

As shown in the figure, the structure is such that four electrodes are attached to the surface of the photodiode. The photocurrent is divided into four by the same resistance layer and output as a position signal. Distortion in the peripheral area is larger than that of the double-sided split type, but it has features such as easy bias application, low dark current, and high-speed response.

(Related technology example 6) FIG. 14 shows a double-sided split type PS.
In the explanatory view of D, (a) shows a schematic configuration and (b) shows an equivalent circuit.

As shown, electrodes are provided on both the front and back surfaces of the photodiode. As is clear from the equivalent circuit, each position signal (photocurrent) is only divided into two by two resistance layers, and therefore the position detection capability (position detection error, resolution) is excellent.

[0067]

The present invention will be described in more detail with reference to the following examples.

(Embodiment 1) FIG. 1 shows Embodiment 1 "2".
1 is a diagram showing a schematic configuration of a "dimensional scanning type dimension measuring device". In the figure, 101 is a two-dimensional galvanometer mirror as shown in related technical examples 2 and 3 capable of two-dimensional scanning (two-dimensional deflection), and 103 Is a PSD as shown in Related Art Examples 5 and 6 capable of detecting the light spot position in two dimensions.

A collimator lens 102 refracts a laser beam 110 incident from the focal point on the mirror of the two-dimensional galvanometer mirror 101 into a scanning beam 111 which is a laser beam parallel to its optical axis. 104 and 107 are P
An amplifier for amplifying the SD output to a required level, 10
Reference numerals 5 and 108 are analog-to-digital converters, and 106 is a microcomputer for performing necessary calculations.

As shown in the figure, when the object to be measured 112 is placed between the collimator lens 102 and the PSD 103, the scanning beam 111 is swung by the two-dimensional galvanometer mirror 101 to scan, and the scanning beam 1 not blocked by the object to be measured 112.
11 reaches the detection surface of the PSD 103, and X-axis data and Y-axis data corresponding to the position thereof are output from the PSD 103. The X-axis data and the Y-axis data are fed to the amplifiers 105 and 10
Amplify to a required level by 8 and AD converter 10
The size of each part in the projected shape 113 of the object 112 to be measured onto the PSD 103 can be obtained by converting into digital data by 5.108 and inputting to the microcomputer 106 for calculation. In addition, the projected area can be obtained from the dimensions of each part.

Here, the photometric surface of the PSD is 10 mm × 10 mm
Therefore, if the A / D conversion output is 8 bits, the minimum scale is 256 μm × 256 dots, which is 40 μm. With 12 bits, the minimum scale is 2.4 μm.

Since the error for each PSD detection position in the present embodiment has a unique value, this error is measured in advance and stored in a memory, and is corrected by the contents of this memory at the time of dimension measurement, whereby a more accurate dimension is obtained. It becomes possible to measure.

As described above, according to the present invention, it is possible to obtain an accurate two-dimensional dimension by using an inexpensive and small galvanometer mirror without using an expensive polygon mirror or a constant velocity rotary drive device. A two-dimensional scanning type size measuring device can be provided. (Embodiment 2) FIG. 2 is a diagram showing the construction of a "two-dimensional scanning type dimension measuring apparatus" which is Embodiment 2. In FIG. The amplifier, the AD converter, and the microcomputer unit are the same as in the first embodiment,
Illustration is omitted.

In this embodiment, as shown in the drawing, the two-dimensional galvanometer mirror 101 is used without using a collimator lens.
The object 112 to be measured is directly scanned by the reflected light 111 of

In this embodiment, the two-dimensional galvanometer mirror 10 is used.
This is equivalent to the case where the object to be measured 112 is irradiated (scanned) with the reflection point of No. 1 as a point light source, and the galvanometer mirror 101 is used.
And the front surface of the DUT 112 is f1, and the distance between the galvano mirror 101 and the detection surface of the PSD 103 is f1 + f.
If it is 2, the size of the projected image 113 of the object to be measured is (f1 + f2) / f1 times the size of the object to be measured 112.

For example, the photometric surface of PSD is 10 mm × 10
mm, A-D conversion is 8 bits, (f1 + f2) / f1 = 1
If 0, the minimum scale is 4 μm.

As described above, according to the present embodiment,
Provided is a two-dimensional scanning type dimension measuring device capable of obtaining an accurate two-dimensional dimension by using an inexpensive and small two-dimensional galvanometer mirror without using an expensive polygon mirror, a constant-speed rotation driving device, and a collimator lens. be able to.

(Embodiment 3) In each of the above embodiments, two-dimensional dimensions are measured, but the present invention is not limited to this.
It can be implemented in the form of measuring one-dimensional dimensions.

At this time, 2 in the first and second embodiments
The galvano mirror of Related Technique Example 1 (see FIG. 3) is used instead of the two-dimensional Galvano mirror 101, and the one-dimensional PSD of Related Technique Example 4 (see FIG. 12) is used instead of the two-dimensional PSD.

According to this embodiment, it is possible to provide a one-dimensional scanning type size measuring device which can obtain an accurate one-dimensional size without using an expensive polygon mirror or a constant-speed rotary driving device.

[0081]

As described above, according to the present invention,
It is possible to provide an inexpensive and compact scanning size measuring device. Further, according to the inventions of claims 3 and 4,
It is possible to provide a scanning-type dimension measuring device that can obtain accurate two-dimensional dimensions.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment.

FIG. 2 is a diagram showing a configuration of a second embodiment.

FIG. 3 is a diagram showing a configuration of Related Art Example 1;

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is an operation explanatory diagram of Related Art Example 1

FIG. 6 is an explanatory diagram of displacement angle detection of a movable plate in Related Art Example 1.

FIG. 7 is a diagram showing a configuration of Related Art Example 2;

FIG. 8 is a diagram showing a configuration of Related Art Example 3;

9 is a sectional view taken along line BB of FIG.

FIG. 10 is a sectional view taken along line CC of FIG.

FIG. 11 is an explanatory diagram of light incident position detection of PSD.

FIG. 12 is an explanatory diagram of a one-dimensional PSD.

FIG. 13 is an explanatory diagram of a surface division type PSD.

FIG. 14 is an explanatory diagram of a double-sided split PSD.

FIG. 15 is a diagram showing a configuration of a conventional example.

[Explanation of symbols]

 100 semiconductor laser 101 two-dimensional galvanometer mirror 103 PSD

Claims (4)

[Claims] 1. A laser beam generating means, a galvano mirror for receiving and deflecting a laser beam from the laser beam generating means, and a light incident position detecting means for receiving the laser beam from the galvano mirror and detecting its incident position. A scanning-type dimension measuring apparatus, comprising: an object to be measured between the galvanometer mirror and the light incident position detecting means, and measuring the dimension of the object to be measured. 2. The scanning size measuring apparatus according to claim 1, further comprising a collimator lens for collimating the laser beam deflected by the galvanometer mirror. 3. The galvanometer mirror is capable of two-dimensional deflection.
The scanning dimension measuring apparatus according to claim 1 or 2, wherein the scanning dimension measuring device is a two-dimensional galvanometer mirror, and the light incident position detecting means is a two-dimensional light incident position detecting means capable of detecting a two-dimensional light incident position. 4. A galvanometer mirror is such that a movable plate and a torsion bar that pivotally supports the movable plate with respect to the semiconductor substrate are integrally formed on a semiconductor substrate, and a drive coil is provided on a peripheral portion of the movable plate. And a mirror provided on the movable plate, magnetic field generating means for applying a static magnetic field to the drive coil is provided, and the mirror is driven by passing a current through the drive coil. The scanning size measuring apparatus according to any one of claims 1 to 3.