JPH06109420A - Optical measuring apparatus - Google Patents

Abstract

PURPOSE:To measure the shape in the X-axis direction and the Y-axis direction of an object under test without circling a sensor part and the object under test. CONSTITUTION:Laser beams from semiconductor lasers 11a, 11b are divided into two sets of laser beams Ba1, Bb1 and Ba2, Bb2 in the X-axis direction and the Y-axis direction by using a beam splitter 12, the laser beams Ba1, Bb1 in the X-axis direction are passed through a polarization beam splitter 13, an object 1 under test is irradiated with the laser beams, the laser beams Ba2, Bb2 in the Y-direction are passed through a polarization beam splitter 15, and the object 1 under test is irradiated with the beams. Images of the laser beams Ba1, Bb1, in the X-axis direction, which are reflected from the object 1 under test are formed on a position detection element 18, and images of the laser beams Ba2, Bb2, in the Y-direction, which are reflected from the object 1 under test are formed on a position detection element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical measuring device for measuring the surface shape of an object to be measured using light from a semiconductor laser or the like.

[0002]

2. Description of the Related Art A conventional optical measuring device will be described with reference to FIG. In FIG. 4, reference numeral 1 denotes an object to be measured, which is an object of shape measurement. The object to be measured 1 is placed on a table (not shown) which can move in the X and Y axis directions and can be swung. There is. Reference numeral 2 denotes a differential autocollimation sensor that measures the surface shape of the DUT 1 without contact.

The differential autocollimation sensor 2 comprises a pair of semiconductor lasers 3a, 3a,
3b, a beam splitter 4 for converting laser light generated from the semiconductor lasers 3a, 3b into parallel beams separated by a predetermined distance and directing the parallel beam to the DUT 1, and a polarized beam arranged on the light beam emission side of the beam splitter 4. The splitter 5 and the quarter-wave plate 6, a beam bender 7 disposed on the side of the polarization beam splitter 5 for redirecting the light beam reflected from the DUT 1, and reflected from the beam bender 7. Position detection including a condenser lens 8 that condenses the light beam, and a PSD or the like that is disposed at the focal position of the condenser lens 8 and that detects the tangent angle of the DUT 1 from the imaging position of the reflected beam light. And element 9.

When the surface shape of the DUT 1 is measured by using the differential autocollimation sensor 2 constructed as described above, the semiconductor lasers 3a and 3b are alternately operated at predetermined intervals to emit laser light. Alternately generate. This laser light is applied to the DUT 1 through the beam splitter 4, the polarization beam splitter 5, and the quarter-wave plate 6.
Then, the reflected lights of the two laser lights reflected on the surface of the DUT 1 are passed through the quarter-wave plate 6 and then bent toward the beam bender 7 by the polarization beam splitter 5 and then by the condenser lens 8. An image is formed on the position detection element 8. At this time, since the signal output according to the image forming position of the reflected light imaged on the position detection element 8 represents the tangent angle of the surface of the DUT 1, the difference between the tangential angles of the two reflected lights is integrated. By doing so, the shape data of the laser irradiation point can be obtained.

Therefore, when obtaining the shape of the entire surface of the DUT 1, the DUT 1 is moved in the X-axis direction every time the DUT 1 is moved in the Y-axis direction by a predetermined amount, and the differential autocollimation is performed. Two light beams B1 and B emitted from the sensor 2
2, the surface of the DUT 1 is scanned in the X-axis direction to obtain shape data in the cross-sectional direction x over the entire surface. Next, the DUT 1 is rotated 90 degrees, and the DUT 1 is moved in the Y-axis direction orthogonal to the previously measured cross-sectional direction x to scan the surface once with the light beams B1 and B2. Shape data in the cross-sectional direction y is obtained. Then, the obtained cross-sectional direction x,
The shape of the entire surface of the DUT 1 is obtained by combining the shape data of y.

[0006]

In order to combine the shape data in the cross-sectional direction x and the shape data in the cross-sectional direction Y, the conventional optical measuring apparatus as described above irradiates the object to be measured with a light beam before turning. The relationship between the position and the irradiation position of the light beam on the measured object after turning must be accurately grasped. Conventionally, since the irradiation position relationship of the light beam before and after the turning is visually obtained, there is a problem of lacking accuracy. In addition, there is a problem that the reproducibility when 90-degree turning indexing is lacking.

The present invention has been made in view of the above circumstances, and is an optical system capable of measuring the shape of an object to be measured in the X-axis direction and the Y-axis direction without rotating the sensor unit and the object to be measured. The purpose is to provide a dynamic measuring device.

[0008]

In order to achieve the above object, the present invention provides a light source for generating two parallel light beams and two light beams for emitting light in the X and Y directions. A beam splitter for splitting into two sets of light beams, a first optical system for irradiating the set of light beams in the X direction toward the object to be measured, and a set of light in the X direction reflected by the object to be measured First position detecting means for detecting an image formation position of the beam, a second optical system for irradiating the object to be measured with the pair of light beams in the Y direction, and a Y direction reflected by the object to be measured. Second position detecting means for detecting the image forming positions of the light beams of the group.

[0009]

With the above structure, the set of light beams in the X direction split by the beam splitter is applied to the object to be measured through the first optical system and scanned in the X direction to perform shape measurement in the X axis direction. Be seen. Then, the light beam in the Y direction divided by the beam splitter is applied to the object to be measured through the second optical system and is scanned in the Y direction, whereby the shape measurement in the Y axis direction is performed. Therefore, it is possible to measure the shape of the measured object in the X-axis direction and the Y-axis direction without turning the measured object or the light beam side.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a block diagram showing an embodiment of an optical measuring device according to the present invention, and FIGS. 2 and 3 are AA in FIG.
It is the top view and side view which follow the line and the BB line. 1 to 3, 10 represents the surface shape of the DUT 1 by X.
This is a differential autocollimation sensor unit that measures in the axial and Y-axis directions.

Differential autocollimation sensor section 10
Are semiconductor lasers 11a and 11b arranged such that the optical axes of the laser beams are orthogonal to each other, and two laser beams generated from the semiconductor lasers 11a and 11b are parallel to each other in two sets for X-axis and Y-axis. Laser beams Ba1 and Bb
1 and beam splitter 1 for splitting into Ba2 and Bb2
2, a polarization beam splitter 13 for the X-axis arranged below the beam splitter 12, and a 1/2 provided on the lower surface of the polarization beam splitter 13 facing the DUT 1 directly.
A four-wave plate 14, a Y-axis polarization beam splitter 15 arranged on the side of the beam splitter 12, and a quarter-wave plate 16 provided on the lower surface of the polarization beam splitter 15 facing the DUT 1 are provided. .

The X-axis polarization beam splitter 1 is also provided.
On the side of 3, the DUT 1 to the polarization beam splitter 1
Laser beams Ba1 and Bb1 reflected through
A beam bender 17 for diverting the laser beam at a right angle is arranged. In the reflection direction of the laser beam by the beam bender 17, a condenser lens 18 for condensing the reflected laser beam and laser beams Ba1, Bb1 by the condenser lens 18 are arranged. A one-dimensional X-axis position detecting element 19 made of PSD or the like for detecting the image forming position is arranged.

The Y-axis polarization beam splitter 15
Is the beam splitter 12 as shown in FIGS.
A beam bender 20 that bends the separated laser beams Ba2 and Bb2 toward the polarization beam splitter 15 is provided. The laser beam including the surface shape component of the DUT 1 is focused on the laser beam transmitting side of the polarization beam splitter 15 which is directed to the DUT 1 and transmits the laser beam reflected by the surface of the DUT 1. And a one-dimensional Y-axis position detecting element 22 including a PSD for detecting the image forming position of the laser beam by the condensing lens.

Next, the operation of this embodiment configured as described above will be described. First, the cross-sectional direction x of the DUT 1
The case of measuring the shape (see FIG. 4) will be described. In this case, the position detecting element 19 for the X axis is in the operating state, and
The position detecting element 22 for the shaft is in the inoperative state.

In this state, the semiconductor laser 11
When a and 11b are alternately operated at predetermined intervals, the laser beams generated from these semiconductor lasers 11a and 11b are split by the beam splitter 12 into two sets of parallel laser beams Ba1, Bb1 and Ba2, Bb2. . Of these, the laser beams Ba1 arranged in the X-axis direction
Bb1 is applied to the DUT 1 through the polarization beam splitter 13 and the quarter-wave plate 14. Then, the laser beams Ba1 and Bb1 reflected on the surface of the DUT 1 are measured.
After passing through the quarter-wave plate 14, the light beam is bent by the polarization beam splitter 13 toward the beam bender 17, and further bent by the beam bender 17 toward the condenser lens 18. The condensing lens 18 condenses the laser beams Ba1 and Bb1 including the shape component of the DUT 1 to detect the position detecting element 1.
9 is imaged.

At this time, the signal output from the position detecting element 19 in accordance with the image forming position of the laser beam imaged on the position detecting element 19 is represented by the tangent angle of the surface of the DUT 1. The shape data of the laser irradiation point can be obtained by integrating twice the tangential angle difference of the beam. Therefore, every time the DUT 1 is moved in the Y-axis direction by a predetermined amount, the DUT 1 is moved in the X-axis direction and emitted from the sensor unit 10 by the laser beams Ba1 and Bb1 in the X-axis direction. If the surface is scanned, the cross-sectional direction x across the entire surface
Can be obtained.

The Y-axis laser beams Ba2 and Bb2 split by the beam splitter 12 scan the surface of the object to be measured 1, and the laser beam reflected from the surface of the object to be measured accompanying the scanning is for the Y-axis. An image is formed on the position detecting element 22, but since the position detecting element 22 is in an inoperative state,
The position signal becomes invalid.

Next, the case of measuring the shape of the DUT 1 in the cross-sectional direction y (see FIG. 4) will be described. in this case,
The Y-axis position detecting element 22 is in the operating state, and the X-axis position detecting element 19 is in the inoperative state. here,
The positions of the laser beams Ba1 and Bb1 in the X-axis direction and the positions of the laser beams Ba2 and Bb2 in the Y-axis direction have a fixed relationship due to the optical system such as the beam splitter 12 and the polarization beam splitter 15, and it is known in advance. Therefore,
It is not necessary to visually determine the positions of the laser beams Ba2 and Bb2 in the Y-axis direction, and the cross-sectional direction x can be obtained only by moving the sensor unit 10 or the DUT 1 in the X- and Y-axis directions.
Positioning in the cross-sectional direction y with respect to can be easily performed.

In this state, when the semiconductor lasers 11a and 11b are alternately operated every predetermined time as in the shape measurement in the X-axis direction, these semiconductor lasers 11a and 1b are operated.
The laser beam generated from 1b is the beam splitter 1
2 splits into two sets of parallel laser beams Ba1, Bb1 and Ba2, Bb2. Of these, the laser beams Ba2 and Bb2 arranged in the Y-axis direction are the beam benders 2
0, polarization beam splitter 15 and quarter-wave plate 16
The object to be measured 1 is irradiated through the through. Then, the DUT 1
The laser beams Ba2 and Bb2 reflected on the surface of
After passing through the four-wave plate 16, the polarization beam splitter 15
It reaches the condenser lens 21 through. In the condenser lens 21, the laser beam Ba2 containing the shape component of the DUT 1 is formed.
Bb2 is condensed and imaged on the position detection element 22.

At this time, the signal output from the position detecting element 22 in accordance with the image forming position of the laser beam imaged on the position detecting element 22 represents the tangential angle of the surface of the DUT 1. The shape data of the laser irradiation point can be obtained by integrating twice the tangential angle difference of the beam. This shape data is stored in a memory (not shown) in association with the coordinates X and Y of the laser irradiation point.

Therefore, the DUT 1 is moved in the Y-axis direction and emitted from the sensor section 10 in the Y-axis direction.
If the surface of the DUT 1 is scanned with 2 and Bb2, the shape data in the cross-sectional direction y can be obtained. This shape data is also the same as
It is stored in the memory in association with the coordinates X and Y of the laser irradiation point.

Finally, by using the coordinates of the laser irradiation point, the shape data in the cross-sectional direction x and the shape data in the cross-sectional direction y are combined by a processing circuit such as a CPU (not shown) to obtain the surface shape of the entire object to be measured. You can

In this embodiment, a laser beam generated from a pair of semiconductor lasers is split by a beam splitter into two sets of laser beams in the X-axis and Y-axis directions. The cross-sectional shape in the X-axis direction is measured by irradiating the DUT with the beam through the polarization beam splitter and the quarter-wave plate. And
By irradiating the object to be measured with a pair of laser beams in the Y-axis direction through the polarization beam splitter and the quarter-wave plate, the cross-sectional shape in the Y-axis direction can be measured.
X direction, Y without turning the sensor unit or DUT
It is possible to measure the shape in the direction. Therefore, it is possible to accurately obtain the positional relationship between the laser irradiation point in the X direction and the laser irradiation point in the Y direction.

Further, since the turning mechanism is not required, the structure of the measuring device is simplified, and the X-axis and the Y-axis are divided into two parts.
Since the pair of laser beams is generated by the optical system, the relative positional relationship between the two laser beams is invariable and stable.

In the above embodiment, the case of generating two sets of laser beams from a pair of semiconductor lasers has been described, but the present invention is not limited to this. For example, using calcite, two laser beams generated from one semiconductor laser are used.
It may be divided into books. Further, the present invention is not limited to the semiconductor laser, other light sources may be used, and various modifications can be made without departing from the scope described in the claims.

[0026]

As described above, according to the present invention, 2
The parallel light beams of the book are split into two sets of light beams in the X and Y directions by the beam splitter, and the light beams of the X direction set are used for shape measurement in the X axis direction. Since it is configured to be used for shape measurement in the Y-axis direction, shape measurement in the X and Y directions of the measured object can be performed without turning the sensor unit or the measured object.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of an optical measuring device according to the present invention.

FIG. 2 is a plan view taken along the line AA of FIG.

FIG. 3 is a side view taken along the line BB of FIG.

FIG. 4 is a configuration diagram of a conventional optical measurement device.

[Explanation of symbols]

 10 Differential Auto Collimation Sensor Section 11a, 11b Semiconductor Laser 12 Beam Splitter 13 Polarization Beam Splitter 14,16 1/4 Wave Plate 15 Polarization Beam Splitter 17,20 Beam Vendor 18,21 Condenser Lens 19,22 Position Detector

Claims (1)

[Claims] 1. A light source that generates two parallel light beams, a beam splitter that splits the two light beams generated from the light source into two sets of light beams in an X direction and a Y direction, and the X direction. A first optical system for irradiating the object to be measured with the group of light beams, and first position detecting means for detecting an image formation position of the group of light beams in the X direction reflected by the object to be measured. , A second optical system for irradiating the object to be measured with the Y-direction set of light beams, and a second optical system for detecting an image-forming position of the Y-direction set of light beams reflected by the object to be measured. An optical measuring device comprising a position detecting means.