JPH04252000A - Aligner - Google Patents

Abstract

PURPOSE:To make it possible to detect relative positional errors between objects with a high precision by dividing light in a range from ultra violet to infrared into multiple channels to allow it pass through a prism with time differences and then pick up the image of an object for the correction of misalignment. CONSTITUTION:To a prism 22 with half mirrors 24 and 25 mounted on its first inclination and a second inclination provided in parallel thereto, ultraviolet light is caused to enter through a cold mirror 21. There are arranged a first object 30 which emits fluorescent when exposed to this ultraviolet light, and a second object 27 above the prism 22. Then, from the rear side thereof, infrared light is made incident on the prism 22. The optical images of the objects 30 and 27 are picked up by image pick up means 31 with time differences thereby to operate the image output signals. In accordance with the electric signal corresponding to the difference between the objects 30 and 27, the object 27 is shifted with respect to the object 30 for alignment. Thus, it becomes possible to detect the relative positional errors with a high precision.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an alignment device for aligning the corresponding positions of two objects or patterns with high precision, and in particular, for highly accurate alignment of the corresponding positions of an electronic component and a board on which the electronic component is mounted. This invention relates to an alignment device for achieving high accuracy.

0002

2. Description of the Related Art When attaching one of two objects to the other using an industrial automatic assembly device, it is necessary to match the corresponding positions of the two objects. In particular, when assembling electronic components, it is necessary to correct the position by calculating the relative positional error between the positioning marks on the printed circuit board and the external shape of the electronic component to be mounted. For this purpose, conventionally, alignment was performed by viewing the board side and the electronic component side using separate video cameras.

However, when aligning two video cameras, errors tend to occur depending on the distance between the cameras and the installation method, which causes positional errors. In addition, there was no reproducibility when reinstalling the entire assembly device, and detailed adjustments were required.

[0004] As an apparatus for solving the above-mentioned problems, there is an alignment apparatus disclosed in, for example, Japanese Patent Application Laid-open No. 182718/1983.

FIG. 4 is a schematic diagram showing an example of the optical device of the alignment device disclosed in the above-mentioned publication. As shown in the figure,
The semi-transparent mirror surfaces 3 and 4 of both prisms 1 and 2 are formed as an integral semi-transparent mirror surface H, and a reflecting mirror 2a is attached to the prism 2, and a reflecting mirror 2a is attached to the prism 2, and a reflecting mirror 2a is attached to the prism 2. A video camera 5 is installed at the observation point position. Further, the input surfaces of both prisms 1 and 2, that is, the surfaces into which light energy from objects 6 and 7 are input, and the surfaces of both prisms 1 and 2,
7, shutters S1 and S2 are interposed, respectively.

According to such an optical device, the image AB of the object 6 and the image CD of the object 7 are observed as images A1 B1 and C1 D1 through the prisms 1 and 2. Since the optical path lengths are different,
The optical path L1 or L2 in the air is adjusted so that the same lens in the video camera 5 forms an image on the same photocathode. In this way, when the shutters S1 and S2 are sequentially opened after adjustment is made to obtain the same image, the images A1 B1 and C1 D1 are individually stored in the video camera 5 as images in sequence. These two sets of image memories A1 B1, C1 D
The difference between the opposing addresses of 1 corresponds to the deviation of the corresponding positional relationship between the two objects 6 and 7.

FIG. 5 is a schematic diagram showing an example of an alignment device using the optical device shown in FIG. 4. An optical device consisting of prisms 1 and 2 and a reflecting mirror 2a is installed at the left end of the movable pedestal 8. Mounted on this pedestal 8 is a video camera 5 and an image processing device 9 equipped with, for example, a microcomputer that processes the image output signals. It has become. Furthermore, an illumination system consisting of illumination lights 10 and 11 for illuminating both objects 6 and 7 is installed at the left end of the pedestal 8.

In the illustrated example, the object 6 is an IC circuit element, for example, and is held by the robot arm 13 via a holder 12, and the other object 7 is an IC circuit element mounting portion on a printed circuit board 14. be. In addition, printed circuit board 1
4 is installed on a movable base 16 which can be finely adjusted in the direction of the arrow by a servo motor 18 via a holder 15.

The output from the image processing device 9, that is, the deviation difference signal between the corresponding positions of the two objects 6 and 7, is input to the servo motor 18, which adjusts the deviation of the movable table 16 in proportion to the signal amount. do. Therefore, by the operation of the servo motor 18, the position of the printed circuit board 14 is finely adjusted via the movable table 16, and when the image formed by the pattern 7 matches the image formed by the object 6,
The output from the image processing device 9 becomes zero, which means that the position correction has been completed and alignment has been performed.

When the alignment is completed, the pedestal 8 is retracted to the right, and the robot arm 13 is then moved downward to move the IC.
The object 6, which is a circuit element, is lowered to the mounting position 7.

[0011]

[Problems to be Solved by the Invention] In the conventional alignment device configured as described above, the illumination systems 10, 11 are installed inside the device.
It was difficult to make it compact. Furthermore, the shutters S1 and S2, which are used to distinguish between the image formed by the object 6 and the image formed by the object 7, are disadvantageous in terms of implementation.

The present invention has been made to solve the above-mentioned problems, and it is possible to compactly configure a device to make it smaller and simpler, and to detect relative position errors between objects with high precision. The purpose is to obtain a positioning device that can be used.

[0013]

Means for Solving the Problems The alignment device according to the present invention has a first slope, a vertical surface, and a second slope provided from the lower end of the vertical surface parallel to the first slope. an inverted trapezoidal prism to which a humirar is attached; a first light source that makes light with a wavelength in the ultraviolet region enter the prism from a first slope via a cold mirror; and a first light source provided below the prism. A first object that emits fluorescence when exposed to ultraviolet light from a light source, a second object provided above the prism, and a wavelength in the infrared region that is emitted by illuminating this second object from the back. a second light source that is incident on the prism; an imaging device that is provided above the prism to capture optical image outputs from each of the first and second objects with a time difference; and image output from the imaging device. an image processing means that receives a signal, performs arithmetic processing on the signal, and outputs an electrical signal corresponding to the difference between the corresponding positions of the first and second objects; and position actuating means for aligning the positions of the two by relatively changing the positions of the two.

[0014]

[Operation] Light in the ultraviolet to infrared region is divided into multiple channels and passed through the prism with a time difference.
The images of the objects are captured by the imaging device, and the differences in the positions of the objects are corrected and the objects are aligned.

[0015]

Embodiment FIG. 1 is a schematic diagram showing the main part of an embodiment of the present invention. In the figure, reference numeral 20 denotes an ultraviolet illumination light source for illuminating ultraviolet light, which has a peak near a wavelength of 365 nm. Reference numeral 21 denotes a cold mirror having spectral transmission characteristics as shown in FIG. 3(a), which allows visible light components with a wavelength of 400 nm or more to pass through and reflects wavelengths around 365 nm. 23a is a first prism having a diamond-shaped cross section;
b is a second prism having a right triangular cross section, and both prisms 23a and 23b are joined to form a prism 22 having an inverted trapezoidal shape. 24 is a first half mirror having spectral transmission characteristics as shown in FIG. 3(b);
It is provided on the right slope portion of 3a in the figure, and transmits about 95% of a component with a wavelength of 365 nm. Reference numeral 25 denotes a second half mirror having spectral transmission characteristics as shown in FIG. . Reference numeral 26 denotes a third half mirror having spectral transmission characteristics as shown in FIG.
About 95% of nm components are transmitted. 27 is an electronic component provided above the vertical plane side of the second prism 23b; 28
is a pad that attracts the electronic component 27.

Reference numeral 29 denotes an infrared light source that illuminates the electronic component 27 from behind and makes light incident on the upper surface of the second prism 23b, and is configured to have a peak near a wavelength of 600 nm. A glass epoxy substrate 30 on which a pattern is drawn is provided below the second prism 23b, and when irradiated with ultraviolet rays, it generates fluorescence having a main component in the wavelength range of 400 nm to 500 nm. Note that 31 is a video camera.

Next, the operation of the present invention constructed as described above will be explained. First, when the power source of the ultraviolet illumination light source 20 is closed, ultraviolet light having a peak near 365 nm is emitted from the ultraviolet illumination light source 20 and hits the cold mirror 21. Here, visible light of 400 nm or more passes through the cold mirror 21, and ultraviolet light of around 365 nm is reflected and reaches the first half mirror 24. Furthermore, the first half mirror
24, about 95% of the ultraviolet light having a wavelength of 365 nm is transmitted and reaches the second half mirror 25. Here, a component with a wavelength of 365 nm is further reflected, and the reflected light is irradiated onto the glass epoxy substrate 30. Therefore, the glass epoxy substrate 30 emits fluorescence having a main component in the wavelength range of 400 nm to 500 nm, and the fluorescence is further reflected by the second half mirror 25 and reaches the first half mirror 24, where it is reflected. and reaches the video camera 31. As a result, the video camera 31 images a pattern on the substrate in the form of a silhouette against the background of the glass epoxy substrate 30 which has emitted fluorescence due to the ultraviolet irradiation.

Next, when the power source of the ultraviolet illumination light source 20 is turned on and the power source of the infrared light source 29 is closed, a wavelength of 600 nm is detected.
The light having a peak near m reaches the second half mirror 25, where it is reflected by about 50%. The reflected light is further reflected by the third half mirror 26, passes through the second half mirror 25 again by 50%, and reaches the first half mirror 24.
and reaches the video camera 31. This results in
An image of the electronic component 27 is captured by a video camera 31 in the form of a silhouette using an infrared light source 29 as a backlight.

FIG. 6 is a schematic diagram of an embodiment of the alignment device according to the present invention. 32 is the optical unit shown in FIG.
Cold mirror 21, prism 22, first, second, third
It is composed of half mirrors 24, 25, and 26. 33 is a Zθ axis arm having a pad 28 at the bottom; 34
35 is a camera control unit, and 35 is an ultraviolet light source device.A camera control unit 34, an ultraviolet light source device 35, and an optical unit 32 are integrally attached to the Zθ-axis arm 33. It is now possible to slide to the left and right in the figure. 37 is a Y-axis arm that moves in the front-rear direction in the figure. Note that 20 is an ultraviolet illumination light source, 27 is an electronic component, 29 is an infrared light source, and 31 is a video camera.

The operation of the present invention constructed as described above will be explained. First, the Zθ-axis arm 33 is moved along the X-axis arm 36.
By moving the Y-axis arm 37, the Zθ-axis arm 33 is moved to the electronic component supply position. Next, slide the optical unit 32 to the right to lower the Zθ-axis arm 33, suck the electronic component 27 and raise it, then slide the optical unit 32 to the left and return it to its original position. , roughly position the electronic component mounting position.

Next, as shown in FIG. 1, the power to the ultraviolet light source device 35 is closed, the power to the infrared light source 29 is turned on, and the video camera 31 is exposed to the pattern of the glass epoxy substrate 30.
After obtaining the image, turn on the power to the ultraviolet light source device 35,
The power of the infrared light source 29 is closed to obtain an image of the electronic component. Then, from both images captured by the video camera 31,
The image processing means calculates minute positional deviation amounts (ΔX, ΔY, Δθ) at the rough electronic component mounting position, and the X-axis arm 36 and Y-axis arm 37, which are position actuating mechanisms, move the The arm 33 is used to finely adjust the Zθ direction. Next, the optical unit 32 is slid to the right, and then the electronic component 27 is lowered using the Zθ-axis arm 33, placed on the glass epoxy substrate 30, released from suction, and raised. Through the above series of operations, the electronic component 27 is attached to the glass epoxy substrate 3.
Installed on 0.

[0022]

As is clear from the above description, the present invention provides a first light source that generates light in the ultraviolet region, a second light source that generates light in the infrared region, and a cold mirror and a half mirror. -, and the ultraviolet light region to the visible light region is divided into a plurality of channels depending on the purpose, resulting in a compact device configuration, so the device can be made compact and simple. Furthermore, since the relative position error between the pattern on the board and the electronic components can be detected without any mechanical movement, highly accurate alignment is possible, and it can be applied to various precision alignment devices. can.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing main parts of an embodiment of the present invention.

FIG. 2 is a schematic diagram of an embodiment of the present invention.

FIGS. 3(a) to 3(d) are diagrams showing the relationship between wavelength and transmittance.

FIG. 4 is a schematic diagram showing an example of an optical device of a conventional alignment device.

FIG. 5 is a schematic diagram showing an example of a conventional alignment device.

[Explanation of symbols]

20 Ultraviolet illumination light source 21 Cold mirror 22 First prism 23 Second prism 24 First half mirror 25 Second half mirror 26 Third half mirror 27 Electronic parts 29 Infrared light source 30 Glass epoxy substrate 31 Video camera 32 Optical unit 33 Zθ axis arm 36 X-axis arm 37 Y-axis arm

Claims (1)

[Claims] 1. An inverted trapezoidal prism in which a half mirror is attached to a first slope, a vertical surface, and a second slope parallel to the first slope from the lower end of the vertical surface. and a cold mirror from the first slope to the prism.
a first light source that allows light with a wavelength in the ultraviolet region to enter through the prism; a first object that is provided below the prism and generates fluorescence when irradiated with ultraviolet light by the first light source; a second object provided above; a second light source that irradiates the second object from the back and makes wavelengths in the infrared region enter the prism; an imaging means for capturing optical image outputs from each of the first and second objects with a time difference;
image processing means for outputting an electrical signal corresponding to the difference in the corresponding position of the object images; A positioning device comprising position actuating means for aligning.