JP2021021644A - Dust detection device - Google Patents

Abstract

To provide a dust detection device capable of identifying a dust generating source and detecting the floating state of dust.SOLUTION: A dust detection device 2 is provided, comprising a light source 4 configured to irradiate at least three types of pulsed light at different times, image capturing means 6 configured to capture images of dust D irradiated with the at least three types of pulsed light emitted from the light source 4, and display means 8 for displaying the images captured by the image capturing means 6.SELECTED DRAWING: Figure 1

Description

The present invention relates to a dust detection device that detects dust.

A wafer in which a plurality of devices such as ICs and LSIs are partitioned by a planned division line and formed on the surface is divided into individual device chips by a dicing device and a laser processing device, and each divided device chip is a mobile phone, a personal computer, etc. Used for electrical equipment in Japan.

The dicing device and the laser processing device include a chuck table that sucks and holds the waha and a processing means that processes the waha that is sucked and held by the chuck table (in the dicing device, a cutting blade that cuts the waha while supplying cutting water). It is generally composed of a rotatably prepared cutting means, and in a laser processing apparatus, a laser beam irradiating means for irradiating a wafer with a laser beam) and a feeding means for relatively processing and feeding a chuck table and a processing means. The waha can be divided into individual device chips with high precision (see, for example, Patent Documents 1 and 2). Such a dicing device and a laser processing device are installed in a clean room with extremely little dust.

Japanese Unexamined Patent Publication No. 2008-279526 JP-A-2007-152355

However, although processing equipment including dicing equipment and laser processing equipment installed in the clean room may discharge dust and contaminate the inside of the clean room, it is difficult to identify the source of the dust and it is possible to detect the floating state of the dust. There is a problem that it is difficult.

An object of the present invention made in view of the above facts is to provide a dust detection device capable of identifying a dust generation source and detecting a floating state of dust.

The present invention provides the following dust detection device in order to solve the above problems. That is, it is a dust detection device that detects dust, and images a light source that irradiates at least three types of pulsed light with a time lag and dust that is illuminated by the at least three types of pulsed light emitted from the light source. The present invention provides a dust detection device including an imaging means and a display means for displaying an image captured by the imaging means.

Preferably, the at least three types of pulsed light are composed of at least three types of colors. The at least three types of pulsed light are preferably composed of at least three types of brightness. A first polarizing filter arranged adjacent to the light source to polarize at least three types of pulsed light emitted from the light source, and a first polarizing filter arranged adjacent to the imaging means and passing through the first polarizing filter. It is convenient to include a second polarizing filter, which is positioned to shield the pulsed light. It is preferable to include a storage means for storing the image captured by the imaging means. When the optical axis of the at least three types of pulsed light irradiated by the light source is the X-axis, the axis orthogonal to the X-axis is the Y-axis, and the axis orthogonal to the X-axis and the Y-axis is the Z-axis. The imaging means includes a first imaging means for imaging the XY plane specified by the X-axis and the Y-axis, and a second imaging means for imaging the XZ plane specified by the X-axis and the Z-axis. It is preferable to provide an imaging means.

The dust detection device of the present invention comprises a light source that irradiates at least three types of pulsed light with a time lag, an imaging means that captures images of dust illuminated by the at least three types of pulsed light emitted from the light source, and the like. Since the imaging means includes a display means for displaying the image captured, the dust scattering direction can be specified from the order of at least three types of pulsed light in the image obtained by capturing the dust, and the same type in the captured image can be specified. The speed of dust can be determined based on the interval of the pulsed light and the repetition frequency of the pulsed light. Therefore, according to the dust detection device of the present invention, it is possible to identify the dust generation source and detect the floating state of the dust.

The perspective view of the dust detection apparatus configured according to this invention. FIG. 6 is a schematic view of an image showing a trajectory of dust on an XY plane imaged by the first imaging means shown in FIG. The schematic diagram of the image which shows the locus of dust on the XZ plane imaged by the 2nd imaging means shown in FIG. A schematic view of an image in which the coordinates of two boundary points are plotted on a YZ plane based on the images shown in FIGS. 2 and 3.

Hereinafter, preferred embodiments of the dust detection device configured according to the present invention will be described with reference to the drawings.

Explaining with reference to FIG. 1, the dust detection device represented by reference numeral 2 is composed of a light source 4 that irradiates at least three types of pulsed light with a time lag and at least three types of pulsed light emitted from the light source 4. An image pickup means 6 for capturing an image of the illuminated dust D and a display means 8 for displaying an image captured by the image pickup means 6 are provided.

The light source 4, which may be composed of a projector or the like, irradiates at least three types of pulsed light one by one with a time lag. The light source 4 of the illustrated embodiment is adapted to irradiate three types (three colors) of pulsed light of red, blue, and green in order at appropriate repeating frequencies (for example, about 120 Hz). The order of the pulsed light emitted from the light source 4 may be arbitrary, but in the illustrated embodiment, the pulsed light is emitted from the light source 4 in the order of red, blue, and green. The at least three types of pulsed light emitted from the light source 4 may be composed of at least three types of brightness.

As shown in FIG. 1, the imaging means 6 of the illustrated embodiment includes a first imaging means 6a that images an XY plane specified by the X-axis and the Y-axis, and an XZ specified by the X-axis and the Z-axis. A second imaging means 6b for imaging a plane is provided. In the illustrated embodiment, the optical axis of at least three types of pulsed light emitted by the light source 4 is the X-axis, the axis orthogonal to the X-axis is the Y-axis, and the axis orthogonal to the X-axis and the Y-axis is Z. Use as the axis.

The first imaging means 6a images an arbitrary region irradiated with three types of pulsed light along the Z-axis direction, and the second imaging means 6b is the same as the region imaged by the first imaging means 6a. The region is imaged along the Y-axis direction. Therefore, the object imaged by the first imaging means 6a is imaged by the second imaging means 6b at an imaging angle different from the imaging angle of the first imaging means 6a.

The exposure times of the first and second imaging means 6a and 6b are set to be sufficiently longer than the repetition period (for example, 1/120 second) of each of the three types of pulsed light emitted from the light source 4. There is. Therefore, when the dust D is suspended in the imaging regions of the first and second imaging means 6a and 6b, the three types of pulsed light emitted from the light source 4 are sequentially scattered by the dust D, and FIGS. As shown in 3, the locus T of the dust D composed of the repeating pattern of the red portion Tr, the blue portion Tb, and the green portion Tg is imaged by the first and second imaging means 6a and 6b. Then, the images captured by the first and second imaging means 6a and 6b are sent to the display means 8.

The dust detection device 2 of the illustrated embodiment is further arranged adjacent to the light source 4 and is adjacent to a first polarizing filter 10 for polarizing at least three types of pulsed light emitted from the light source 4 and an imaging means 6. A second polarizing filter 12 is provided so as to shield the pulsed light that has passed through the first polarizing filter 10. As shown in FIG. 1, the second polarizing filter 12 is arranged adjacent to the first imaging means filter 12a and the second imaging means 6b arranged adjacent to the first imaging means 6a. It has a second filter for imaging means 12b.

The polarization directions of the first and second imaging means filters 12a and 12b are orthogonal to the polarization directions of the first polarizing filter 10. Therefore, if dust D is not present in the imaging regions of the first and second imaging means 6a and 6b, the pulsed light emitted from the light source 4 and passed through the first polarizing filter 10 is used for the first and second imaging means. It is shielded by the filters 12a and 12b so that it does not enter the first and second imaging means 6a and 6b.

On the other hand, when dust D is present in the imaging regions of the first and second imaging means 6a and 6b, the pulsed light emitted from the light source 4 and passed through the first polarizing filter 10 is scattered by the dust D and scattered pulsed light. Is not shielded by the first and second imaging means filters 12a and 12b, and is imaged as the trajectory T of the dust D by the first and second imaging means 6a and 6b. Further, when the first and second polarizing filters 10 and 12 are arranged, the contrast of the images captured by the first and second imaging means 6a and 6b becomes large, and the trajectory T of the dust D becomes large. Is imaged more clearly.

The dust detection device 2 of the illustrated embodiment further includes a storage means 14 for storing an image captured by the image pickup means 6. Each image captured by the first and second imaging means 6a and 6b is displayed on the display means 8 and stored in the storage means 14.

When the dust D is detected by the dust detection device 2 as described above, three types of pulsed light are irradiated one by one in order from the light source 4 at an appropriate repeating frequency with a time lag. Then, when the dust D is suspended in the imaging regions of the first and second imaging means 6a and 6b, the three types (three colors) of pulsed light emitted from the light source 4 are sequentially scattered by the dust D, and the figure shows the figure. As shown in 2 and FIG. 3, the locus T of the dust D composed of the repeating pattern of the red portion Tr, the blue portion Tb, and the green portion Tg is imaged by the first and second imaging means 6a and 6b.

From the images of the trajectory T of the dust D captured by the first and second imaging means 6a and 6b, the scattering direction of the dust D and the speed of the dust D can be obtained.

First, the scattering direction of the dust D will be described with reference to FIGS. 2 to 4. As described above, the light source 4 of the illustrated embodiment irradiates three types of pulsed light in the order of red, blue, and green. Therefore, the dust D scatters the pulsed light in the order of red, blue, and green. With reference to FIG. 2, since the locus T has a repeating pattern in the order of the red portion Tr, the blue portion Tb, and the green portion Tg from the upper left to the lower right of FIG. 2, the dust D is scattered on the XY plane. The direction is the direction indicated by the arrow Axy. With reference to FIG. 3, since the locus T has a repeating pattern in the order of the red portion Tr, the blue portion Tb, and the green portion Tg from the lower left to the upper right of FIG. 3, the scattering direction of the dust D on the XZ plane. Is the direction indicated by the arrow Axz.

Further, when determining the scattering direction of the dust D on the YZ plane, first, as shown in FIGS. 2 and 3, P ₁ is set at an arbitrary boundary point between the green portion Tg and the red portion Tr in the trajectory T of the dust D. Let P _{2 be} the boundary point between the green portion Tg and the red portion Tr on the downstream side of P ₁ . Then, the image shown in FIG. 2, to identify the X and Y coordinates of _{P 1 (X 1, Y 1} ), an X-coordinate and Y-coordinate of _{P 2 (X} 2, _{Y 2).} Further, the image shown in FIG. 3, is identified as X and Z coordinates of _{P 1 (X 1, Z 1} ), and X and Z coordinates of _{P 2 (X 2, Z 2} ).

Then, as shown in FIG. 4, Y-coordinate and Z-coordinate _(Y 1, _{Z 1)} of _{P 1} identified from the image shown in FIGS. 2 and 3 as well as _{P 2} Y-coordinate and Z-coordinate _{(Y 2, Z} 2) Is plotted on the YZ plane. Since the dust D is scattered from P ₁ to P ₂ , it can be determined that the direction indicated by the arrow Ayz in FIG. 4 is the scattering direction of the dust D on the YZ plane. In this way, the scattering directions (Axy, Ax, Ayz) of the dust D can be obtained from the order of the three types of pulsed light in the image obtained by capturing the dust D. Note that P ₁ and P ₂ are not limited to the boundary point between the green portion Tg and the red portion Tr.

Next, determining the speed of the dust D based on the interval of the same type of pulsed light in the captured image and the repetition frequency of the pulsed light will be described with reference to FIGS. 2 to 4. In the illustrated embodiment, it is assumed that the repetition frequency of the pulsed light is set to 120 Hz.

First, regarding the velocity Vxy of the dust D on the XY plane, assuming that the length from P ₁ to P ₂ (interval between pulsed lights of the same type in the captured image) is 30 mm as shown in FIG.
Vxy = 30 (mm) x 120 (Hz)
= 3600 (mm / s)
Will be.

Regarding the velocity Vxz of the dust D on the XZ plane, assuming that the length from P ₁ to P ₂ is 32 mm as shown in FIG.
Vxz = 32 (mm) x 120 (Hz)
= 3840 (mm / s)
Will be.

Regarding the velocity Vyz of the dust D on the YZ plane, assuming that the length from P ₁ to P ₂ is 19 mm as shown in FIG.
Vyz = 19 (mm) x 120 (Hz)
= 2280 (mm / s)
Will be.

Further, regarding the relationship between the coordinates of P _{1 and} the coordinates of P ₂ , the following equations 1 to 3 are derived from the images shown in FIGS. 2 to 4 by using the three-square theorem.
Equation 1 (X _2- X ₁ ) ² + (Y _2- Y ₁ ) ² = 30 ²
Equation 2 (X _2- X ₁ ) ² + (Z _2- Z ₁ ) ² = 32 ²
Equation ^{_{3 (Y 2 -Y 1) 2}} + (Z 2 -Z 1) 2 = 19 2

The distance from P ₁ to P _{2 in} three-dimensional space is L = {(X _2- X ₁ ) ² + (Y _2- Y ₁ ) ² + (Z _2- Z ₁ ) ² } ^1/2
The velocity V of the dust D in the three-dimensional space is the above distance L and the repetition frequency (120 Hz).
V = L (mm) x 120 (Hz)
= {(X _2- X ₁ ) ² + (Y _2- Y ₁ ) ² + (Z _2- Z ₁ ) ² } ^1/2 x 120
It can be expressed as. Here, when the above equations 1 to 3 are used,
^{V = {(30 2 +32 2} +19 2) / 2} 1/2 × 120
= 33.8 × 120
= 4056 (mm / s)
Will be. In this way, the velocity (V, Vxy, Vxz, Vyz) of the dust D can be obtained based on the interval of the same type of pulsed light and the repetition frequency of the pulsed light in the image obtained by capturing the dust D.

As described above, in the dust detection device 2 of the illustrated embodiment, by imaging the dust D illuminated by at least three types of pulsed light, the dust is dusted from the order of at least three types of pulsed light in the captured image. The scattering direction of D can be specified, and the speed V of dust D can be obtained based on the repetition frequency of the pulsed light and the interval of the pulsed light of the same type in the captured image. Therefore, according to the dust detection device 2 of the illustrated embodiment, the dust generation source can be specified and the floating state of the dust D can be detected.

2: Dust detection device 4: Light source 6: Imaging means 6a: First imaging means 6b: Second imaging means 8: Display means 10: First polarizing filter 12: Second polarizing filter 12a: First imaging Means filter 12b: Second imaging means filter 14: Storage means D: Dust

Claims (6)

It is a dust detection device that detects dust.
A light source that irradiates at least three types of pulsed light with a time lag, an imaging means that captures dust illuminated by the at least three types of pulsed light emitted from the light source, and an image captured by the imaging means are displayed. A dust detection device comprising a display means to be used. The dust detection device according to claim 1, wherein the at least three types of pulsed light are composed of at least three types of colors. The dust detection device according to claim 1, wherein the at least three types of pulsed light are composed of at least three types of brightness. A first polarizing filter arranged adjacent to the light source to polarize at least three types of pulsed light emitted from the light source, and a first polarizing filter arranged adjacent to the imaging means and passing through the first polarizing filter. The dust detection device according to claim 1, further comprising a second polarizing filter positioned so as to shield the pulsed light. The dust detection device according to claim 1, further comprising a storage means for storing an image captured by the image pickup means. When the optical axis of the at least three types of pulsed light emitted by the light source is the X-axis, the axis orthogonal to the X-axis is the Y-axis, and the axis orthogonal to the X-axis and the Y-axis is the Z-axis. The imaging means includes a first imaging means for imaging the XY plane specified by the X-axis and the Y-axis, and a second imaging means for imaging the XZ plane specified by the X-axis and the Z-axis. The dust detection device according to claim 1, further comprising an imaging means.