JP3287345B2 - Particle monitoring device, particle monitoring method, and recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particle monitoring apparatus, a particle monitoring method, and a recording medium for monitoring particles such as dust generated during semiconductor manufacturing by using a laser beam. The present invention relates to a particle monitoring device, a particle monitoring method, and a recording medium that monitor particles in real time using the same.

[0002]

2. Description of the Related Art When a semiconductor is manufactured, particles such as dust are generated in the manufacturing chamber. When such particles adhere to the semiconductor, they cause the performance and the like of the semiconductor to deteriorate. Therefore, many devices for measuring particles have been developed in order to determine the cause and mechanism of generation of particles in a semiconductor manufacturing chamber, or to control a semiconductor manufacturing apparatus to suppress generation of particles.

[0003] An example of a conventional particle monitor system is disclosed in "Journal of Vacuum Science and Technology" published in 1991.
f Vacuum Science and Technology), Vol. B9, pages 3487 to 3492, and the same magazine published in 1996, Vol. A14, pages 649 to 654. Selwyn). As shown in FIG. 9, an introduction window 16 for introducing a laser beam emitted from the laser light source 11 and a particle 19 introduced into the reaction chamber 15 and scattered on the wall surface of the reaction chamber 15 of the process apparatus. A detection window 17 for measuring the laser light from outside the reaction chamber 15 is provided.

[0004] The particle monitor system operates as follows. The laser light emitted from the laser light source 11 is reflected by the oscillating mirror 13 and then introduced into the reaction chamber 15 through the introduction window 16. Reaction chamber 1
The laser light introduced into 5 is scattered when striking particles 19, and the scattered light is detected by scattered light detector 12 such as a CCD camera through detection window 17. The detected scattered light is recorded as a moving image, and the time and intensity change of the scattered light are indicated from the moving image, and as a result, the generation state of the particles 19 can be known. A beam damper 18 for absorbing the laser light is attached to a region of the reaction chamber 15 where the laser light introduced through the introduction window 16 reaches.

[0005] Other than the above, techniques for detecting information on particles generated in a manufacturing chamber for manufacturing semiconductors are disclosed in JP-A-4-54440, JP-A-5-273110, and JP-A-6-82358. And JP-A-9-2
No. 43549.

In the technique disclosed in Japanese Patent Application Laid-Open No. 4-54440, two laser beams are scanned in a fan shape by a rotating mirror, laser beams scattered by particles are detected by a detector, and the presence / absence of particles is determined. The speed of movement is measured.

The technique disclosed in Japanese Patent Application Laid-Open No. 5-273110 is a technique for obtaining the size (diameter) of a particle that is sufficiently smaller than the wavelength of laser light. In this technique, in image data of scattered light, the maximum scattered intensity is obtained based on the scattered intensity of each pixel. As described in the official gazette, the integrated scattered intensity is proportional to the maximum scattered intensity. We use the relationship that is also proportional to the power to determine the size of the particles.

The technique disclosed in Japanese Patent Application Laid-Open No. 6-82358 uses laser light including red, green, and blue light, and uses the laser light based on a difference in wavelength and a difference in particle size. It takes advantage of the different scattering. In this technique, the size of particles is measured by viewing the color of the scattered laser light on a television monitor.

The technique disclosed in Japanese Patent Application Laid-Open No. 9-243549 is to irradiate a laser beam in a fan shape with a rotating mirror and detect the laser beam scattered by particles. In this technique, information on the three-dimensional distribution of particles is obtained using a plurality of laser light sources and a plurality of scattered light detectors.

[0010]

In order to efficiently control particles generated in a semiconductor manufacturing apparatus, it is necessary to obtain information such as the size and number of particles in real time.

However, the particle monitor system described in the above-mentioned article uses a moving image of the detected scattered light. Therefore, when the particle image in the image is extremely complicated, information on the size of the particles is used. There is a problem that it is difficult to obtain in real time.

According to the technique disclosed in Japanese Patent Application Laid-Open No. 4-54440, it is possible to determine the presence or absence of particles and the moving speed thereof.
There is a problem that it is not possible to obtain information on the size of each particle or the like.

In the technique disclosed in Japanese Patent Application Laid-Open No. 5-273110, the sixth root of the maximum scattering intensity must be calculated in order to determine the size of the particles from the measured maximum scattering intensity. Therefore, there is a problem that a calculation program becomes complicated, a long time is required for the calculation, and a long time is required to obtain information on particles in real time.

In the technique disclosed in Japanese Patent Application Laid-Open No. 6-82358, information on the size of particles is obtained from the difference in color shown on a television monitor. Therefore, when the obtained particle image is complicated, there is a problem that it is difficult to correctly grasp the particle size. Further, when analyzing the size of particles using a measuring device, there is a problem in that the device for analyzing color becomes complicated and much analysis time is required, so that information on particles cannot be obtained in real time.

In the technique disclosed in Japanese Patent Application Laid-Open No. 9-243549, a plurality of laser light sources and a plurality of scattered light detectors are used.

Accordingly, an object of the present invention is to provide a particle monitor device, a particle monitor method, and a recording medium capable of obtaining various kinds of information of particles in real time with a simple configuration.

[0017]

In order to achieve the above object, a particle monitoring apparatus according to a first aspect of the present invention comprises: a laser irradiating means for irradiating a laser beam to a particle monitoring target area; comprising a distributed multiple of light receiving elements, receiving scattered light scattered by a plurality of the particles the laser beam, a light receiving means for outputting the image data representing the luminance values of a plurality of pixels, said light receiving means outputs using said image data, previously set
Adjacent to each other with a brightness value above a defined threshold
A group of pixels is detected as a pixel region corresponding to a region where scattered light scattered by one particle is incident, and a luminance value of each pixel included in the pixel region is detected.
A region detecting means for outputting a high-luminance pixel information indicating the
A maximum luminance value detecting means for detecting a maximum luminance value in the pixel area using the high luminance pixel information;
Pixel using the information to count the number of pixels in the pixel area
Using the number counting means and the high-brightness pixel information,
Summing means for calculating the sum of the brightness values in the elementary region, and comparing the maximum brightness value , the number of pixels, and each of the sums with a preset reference value, thereby obtaining a relative size of the particles. And a size measuring means for measuring the According to the present invention, the relative size of the particles can be obtained only by comparing the maximum luminance values. Therefore, the time required to determine the relative size of the particles is short, and information on the size of the particles can be obtained in real time.

The image data output by the light receiving means is
Among the luminance values shown, a luminance value less than the threshold value is set to zero.
Initialization means for resetting the area,
The means for resetting the brightness value by the initialization means;
The pixel area may be detected using image data.

The area detecting means uses the image data.
The pixels are scanned one by one using the
When one first pixel having a value is detected, the first pixel is connected to the first pixel.
And a second image having a luminance value equal to or greater than the threshold value.
All the elements are detected, and the first pixel and the second pixel
A stop region may be detected as the pixel region.

The area detecting means detects one of the pixel areas.
Every time the image data is output,
Reset means to reset the brightness value of the pixel to be reset to zero.
In addition, the area detecting means may include one pixel area.
Is detected, the reset means sets one pixel area
Each time the brightness value of the included pixel is reset to zero, another
One pixel region may be detected.

The size measuring means includes the maximum luminance value,
The number of pixels and the parameters obtained from each of the sums
Multiply the size of the article by a preset weight
The relative size of the particles
You may ask for size.

The part measured by the size measuring means is
Display means for displaying the relative size of the vehicle.
You may get.

A counter, wherein the area detecting means includes
Each time one pixel area is detected, the count value of the counter
Count the number of particles by incrementing
Further comprising a particle number counting means,
When the image data does not have the pixel area,
The display means outputs zero information indicating that there is no pixel area.
The display means responds to the zero information in response to the zero information.
Displays the number of particles counted by the particle counting means
May be.

The maximum luminance value is detected by the maximum luminance value detecting means.
Measuring the intensity of the scattered light from the maximum luminance value.
Measuring means, the strength determined by the intensity measuring means
Scattered light intensity, absolutely scattered light intensity and particle
Using a relational expression showing the relationship with the
Measurement means for determining the absolute size of the vehicle
May be provided.

In a particle monitoring method according to a second aspect of the present invention, a laser irradiation step of irradiating a laser beam to a particle monitoring target area and a plurality of light-receiving elements arranged in a matrix are used. Receiving the scattered light of the laser light scattered by the particles,
Each other with a light receiving step of outputting the image data representing the luminance values of a plurality of pixels, using the image data outputted by the light receiving step, a preset threshold or more luminance values
A group of adjacent pixels is detected as a pixel region corresponding to a region where scattered light scattered by one particle is incident, and each of the pixels included in the pixel region is detected.
A region detecting step of outputting a high-luminance pixel information representing the luminance value of the pixels, using the high-luminance pixel information, the highest luminance value detection step of detecting a maximum luminance value of the pixel area, wherein
Using the high brightness pixel information, the number of pixels in the pixel area is calculated.
Using the high-brightness pixel information to count the number of pixels to be counted
Summing step of calculating a sum of brightness values in the pixel area
And the maximum luminance value , the number of pixels, and the sum of the sum.
Each is compared with a preset reference value .
And a size measuring step of measuring a relative size of the particles. According to the present invention, the relative size of the particles can be determined only by comparing the maximum luminance values. Therefore, the time required to determine the relative size of the particles is short, and information on the size of the particles can be obtained in real time.

Computer according to a third aspect of the present invention
The readable recording medium stores the computer
A plurality of light receiving elements arranged in a matrix
The receiver that receives the scattered light scattered by the
Uses image data that shows the brightness values of multiple pixels to be output
And has a luminance value equal to or higher than a preset threshold value.
A group of adjacent pixels is
The area where the scattered light scattered by the
Corresponding pixel area, and each pixel area
Area detection that outputs high-luminance pixel information indicating the luminance value of a pixel
Means and the pixel area using the high brightness pixel information.
Maximum luminance value detecting means for detecting the maximum luminance value in the
Using the high brightness pixel information, the number of pixels in the pixel area is calculated.
Uses the number-of-pixels counting means for counting and the high-brightness pixel information
Summing means for calculating a sum of brightness values in the pixel area
And the maximum luminance value, the number of pixels, and the sum of the sum.
Each is compared with a preset reference value.
Size measurement to measure the relative size of particles
Function as a particle monitor device comprising:
It records the program and data to be used.

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

Next, a particle monitor system according to a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a particle monitor system.

The particle monitor system includes a computer 100, a laser light source device 110, a process device 120, and a scattered light detector 130.

The computer 100 has functions of a device called a central processing unit, a processor, or a data processing device (data transfer, program control, system management, etc.). Specifically, the computer 100 controls the particle monitor system and processes monitored data and the like.

The laser light source device 110 is a computer 1
In response to the control signal from 00, the process device 120 is irradiated with the laser light 140. The region irradiated with the laser light 140 is a region corresponding to the cross-sectional area of the laser light 140, but some particles generated in the process device 120 always enter the irradiation region of the laser light 140. Therefore, the laser light source device 110 does not necessarily
There is no need to scan 0. In addition, the process device 120
The number of particles generated in the process apparatus is calculated by the number of particles per cross-sectional area of the laser beam 140 and the cross-sectional area of the laser beam 140.
It is determined by multiplying the ratio of the cross-sectional area of 20 (the cross-sectional area of the process apparatus 120 / the cross-sectional area of the laser beam 140). Since the obtained number of particles is an approximate value, the cross-sectional area of the laser beam 140 must be adjusted so as to obtain necessary accuracy.

The process device 120 is a device for manufacturing a semiconductor. At the time of semiconductor manufacturing, the process equipment 1
Particles such as dust are generated in the semiconductor device 20, and cause a performance defect or the like in the semiconductor. The process apparatus 120 has a window 121 for receiving a laser beam 140, a window 122 for emitting a laser beam (scattered light 150) scattered by particles (particles) in the apparatus, and a surface facing the window 121. And an absorber 123 for absorbing the laser light 140 that has not been scattered.

The scattered light detector 130 is a CCD (Charge Cou) having a plurality of light receiving elements arranged in a matrix.
pled Device) Equipped with a camera. Then, the scattered light detector 130 detects the scattered light 150 of the laser light 140 emitted from the process device 120 and outputs the scattered light 150 to the computer 100 as two-dimensional image data. In the two-dimensional image data, coordinates indicating the position of a pixel are associated with the luminance value of each pixel. For example, an image of the scattered light 150 obtained by the CCD camera is composed of a plurality of pixels (each square in the figure) as shown in FIG. The position of each pixel is indicated by coordinates such as (i, j).

Next, the configuration of the computer 100 will be further described. The computer 100 shown in FIG.
As shown in the figure, functionally, an area searching unit 101, an intra-area maximum luminance value detecting unit 102, and an intra-area luminance value sum calculating unit 1
03, the number-of-pixels-in-region counting section 104, the number-of-particles counting section 105, the number-of-particles generation / size notification section 10
6, an input unit 107, and a display unit 108.

The area search unit 101 includes a memory or the like and stores a threshold value input from the input unit 107 in advance. Further, the area search unit 101 processes the two-dimensional image data by a method described later using the two-dimensional image data input from the scattered light detector 130 and the stored threshold value, and A group of pixel regions (high-luminance pixel regions) having the above-described luminance values is detected. Then, the area search unit 101
Takes out the detected position of the high-luminance pixel area and the luminance value of the light, and as the high-luminance pixel information, the maximum luminance value detection section 102 within the area, the total luminance value calculation section 103 within the area, the pixel number counting section 104 within the area, And a particle generation number counting unit 105
Output to If the high-luminance pixel area cannot be detected, the area search unit 101 outputs zero information indicating that no high-luminance pixel area exists to the particle occurrence number / size notification unit 106.

The maximum luminance value detection unit 102 within the area uses the high luminance pixel information input from the area search unit 101 to
The maximum luminance value included in the high luminance pixel area is detected and output to the particle generation number / size notification unit 106 as maximum luminance value information.

The intra-region total brightness value calculation unit 103 uses the high-luminance pixel information input from the region search unit 101 to calculate
The sum of the brightness values included in the high brightness pixel area is obtained, and the number of generated particles / size notification unit 1 is used as the brightness sum information.
06 is output.

The intra-region pixel number counting unit 104 counts the number of pixels included in the high-luminance pixel region using the high-luminance pixel information input from the region search unit 101, and generates particle generation information as particle pixel number information. Output to the number / size notification unit 106.

The particle generation number counting unit 105 includes a counter. Each time high-luminance pixel information is input from the area search unit 101, the count value of the counter is increased by one, and the count value is used as particle number information. The number of occurrences/
Output to the size notification unit 106.

The laser light 140 generated by the above-described particles is used.
Scattering depends on the size of the scattering particles. Therefore, the maximum luminance value information, the luminance value total information, and the particle pixel number information from each of the intra-region maximum luminance value detection unit 102, the intra-region luminance value sum calculation unit 103, and the intra-region pixel number counting unit 104 are: , Respectively, indicate the size of the particles.
Further, the particle number information from the particle generation number counting unit 105 indicates information on the particle generation number.

Particle generation number / size notification section 106
Has a memory or the like, and stores, as reference data, a maximum luminance value, a total sum of luminance values, and the number of pixels, which are input in advance from the input unit 106, as a reference. Then, the particle generation number / size notification unit 106 sets the maximum luminance value detection unit 1 in the area.
02, information input from the in-region luminance value sum calculation unit 103 and the in-region pixel number counting unit 104 are compared with the values indicated by the reference data to determine the relative size of the particles. Subsequently, the number of generated particles / size notification unit 1
06 is the size of the particle obtained for each information, and the input unit 10
7 is weighted in advance and averaged to obtain the relative size of the particles.
Output to Further, in response to the zero information input from area search section 101, particle generation number / size notification section 106 outputs the particle number information input from particle generation number counting section 105 to display section 108.

The input unit 107 includes a keyboard and the like, and the area search unit 101 uses the threshold value used in processing of the two-dimensional image data and the number / size notification unit 1 of particle generation.
Reference numeral 06 inputs reference data or the like used when obtaining the relative size of the particles. In addition, when a predetermined key of the keyboard is pressed, a control signal or the like for controlling the laser light source device 110 and the above-described units is output.

The display unit 108 outputs information on the size and number of particles input from the particle generation number / size notification unit 107. Information on the size and number of the particles is displayed on the screen of the computer 100, for example.

Next, the operation of the particle monitor system having the above configuration will be described. Initially, the user of the particle monitor system
Of the input unit 107 (keyboard) is pressed.
With this depression, an irradiation signal for instructing the laser light source device 110 to irradiate the laser light 140 is output from the computer 100, and the laser light source device 110
The laser light 140 is radiated into 0.

The window 121 provided in the process device 120
The laser light 140 incident from the optical path is scattered if particles exist on the optical path. Scattered light 150 of laser light 140
Are emitted from the window 122 provided in the process apparatus 120 and enter the scattered light detector 130.

The scattered light 15 incident on the scattered light detector 130
0 is received by a CCD camera or the like and output to the computer 100 as two-dimensional image data.

The computer 100 includes a scattered light detector 13
In response to the input of two-dimensional image data from 0, a pixel search process is started.

FIG. 4 is a flowchart showing a pixel search process performed by the computer 100.

The area search unit 101 includes a scattered light detector 130
To obtain the two-dimensional image data input to the computer 100 (step S100).

The area search unit 101 compares the luminance value of each pixel represented by the two-dimensional image data with a threshold value previously input from the input unit 107, and sets the luminance value of a pixel less than the threshold value to zero. It is reset (step S101).

Next, the area search unit 101 scans pixels one by one using the processed two-dimensional image data, and detects pixels having a luminance value equal to or higher than the threshold value (step S10).
2). This pixel scanning method is, for example, as shown in FIG.
1), (1, 2) ... (1, n), (2, 1), ...
.., (2, n),...

When a pixel having a luminance value equal to or higher than the threshold value is detected (step S103; YES), the area search unit 10
1 detects a pixel having a luminance value equal to or higher than a threshold value among pixels adjacent to the detected pixel (step S10).
4). For example, assuming that a hatched portion in FIG. 2 is a pixel having a luminance value equal to or greater than a threshold value, the area searching unit 101
Scanning is performed in order from the pixel (1, 1), and the pixel (2,
2) is detected first. Then, (1,2), (2,1), (2,3), (3,2) adjacent to (2,2)
Of the pixels having the luminance value equal to or higher than the threshold value are detected.

When a pixel having a luminance value equal to or higher than the threshold value is detected (step S105; YES), the area search unit 10
1 returns to step S104, and among the pixels adjacent to the detected pixel, a pixel whose luminance value is equal to or larger than the threshold is detected (step S104). Note that the area search unit 101 excludes the pixel once detected from the search target. In FIG. 2, the pixel of (3, 2) is detected in step S104, and the process returns to step S104 to return to (3, 1), (3, 3), and (4, 2) adjacent to (3, 2). Among the pixels, a pixel whose luminance value is equal to or larger than a threshold value is detected.

When a pixel having a luminance value equal to or higher than the threshold value cannot be detected (step S105; NO), the area search unit 101 determines the position (coordinate) of the pixel having the luminance value equal to or higher than the detected threshold value and Assuming that the information indicating the luminance value is high luminance pixel information, the maximum luminance value detection unit 102 within the region, the total luminance value calculation unit 103 within the region, the pixel number counting unit 104 within the region,
The number is output to the particle count counting unit 105. Note that a group of adjacent pixels (high-brightness pixel areas) detected until the result of the determination in step S105 becomes NO is a pixel area indicating an area where the scattered light 150 scattered by one particle is incident.

The maximum luminance value detection unit 102 in the area obtains the maximum luminance value among the luminance values of the light in the high luminance pixel area using the input high luminance pixel information (step S1).
06).

The in-region brightness value sum calculation unit 103 calculates the sum of brightness values of light in the high brightness pixel region using the input high brightness pixel information (step S107).

The intra-region pixel number coefficient section 104 calculates the number of pixels in the high-luminance pixel region using the input high-luminance pixel information (step S108).

The particle count counting unit 105 increases the count value of the counter by 1 in response to the input of the high luminance pixel information (step S109). High brightness pixel information is
Since the information is about the scattered light 150 scattered by one particle, the count value indicates the number of detected particles.

The values obtained by the intra-region maximum luminance value detection unit 102, the intra-region luminance value sum calculation unit 103, and the intra-region pixel number counting unit 104 are maximum luminance value information, luminance value total information, The number of generated particles / size notification unit 106 is output as pixel number information. Further, the count value counted by the particle generation number counting unit 105 is:
Particle number / size notification unit 1 as particle number information
06 is output. The particle number information is output from the display unit 108 as the number of particles generated in step S112, as described later.

The number of generated particles / size notifying section 106
Compares the input maximum luminance value information, luminance value sum information, and particle pixel number information with reference data, and obtains the relative size of the particles for each piece of information. Then, the particle generation number / size notification unit 106 multiplies the size obtained for each piece of information by a predetermined weight, takes an average, and displays information about the averaged particle size obtained by the display unit 108. To be displayed (step S110).

After outputting the high luminance pixel information, the area search unit 101 resets the luminance value of the detected high luminance pixel area to zero (step S111), and returns to step S102. In step S111, the brightness value of the detected pixel is reset to zero.
When the pixel is scanned at 102, the pixel that is first detected as a pixel having a luminance value equal to or higher than the threshold value is (5, 5) in FIG.
6) Pixels.

The above processing is repeated until it is determined in step S103 that there is no pixel having a luminance value equal to or larger than the threshold value.

If no pixel having a luminance value equal to or higher than the threshold value is detected in step S103 (step S10)
3; NO), the area search unit 101 outputs to the particle generation number / size notification unit 106, zero information indicating that there is no pixel having a luminance value equal to or greater than the threshold value. Then, in response to the input of the zero information from region search section 101, particle generation number / size notification section 106 outputs the stored particle number information from particle generation number coefficient section 105 to display section 108. Then, it is displayed on the screen of the computer 100 (step S112).

The area search unit 101 determines whether or not the user of the particle monitor system has pressed a predetermined key of the input unit 107 (keyboard), and received an end signal indicating the end of the pixel search processing from the input unit 107. A determination is made (step S113).

If the end signal has not been output (step S113; NO), the process returns to step S100.
The area search unit 101 acquires unprocessed two-dimensional image data (step S100).

When an end signal is output (step S1)
13; YES), the area search unit 101 ends the pixel search processing without acquiring the two-dimensional image data. The end signal output from the input unit 107 is the laser light source device 11
It is also output to 0. And the laser light source device 110
In response to the input of the end signal, the irradiation of the laser beam 140 ends.

As described above, the above processing (step S1)
The processing from 00 to 113) is repeated until a predetermined key of the input unit 107 (keyboard) is pressed and an end signal is output.

Further, as described above, the information on the particle size is displayed on the screen of the computer 100 in real time, so that it is possible to know at any time what kind of particle is being generated. Can be. Therefore, the semiconductor manufacturing apparatus can be controlled such that generation of particles in the semiconductor manufacturing apparatus is reduced.

Next, a particle monitor system according to a second embodiment of the present invention will be described with reference to the drawings. The physical configuration of the particle monitor system according to the second embodiment is substantially the same as that of the first embodiment (FIG. 1). However, the functional configuration of the particle monitor system according to the second embodiment is different from that of the first embodiment. More specifically, as shown in FIG. 5, the computer 100 further includes a particle size calculation unit 109 in addition to the configuration (FIG. 3) described in the first embodiment.

The area search unit 1 of the computer 100
01, the high luminance pixel information indicating the position of the detected high luminance pixel area and the luminance value of the light,
2. Output to the in-region luminance value sum calculation unit 103, the in-region pixel number counting unit 104, and the particle generation number counting unit 105, and also output to the particle size calculation unit 109.

The particle size calculator 109 has a memory and the like, and stores parameters, programs and the like input in advance. Specifically, the particle size calculation unit 109 calculates a particle size (reference particle size) that is used as a reference for comparing the program and parameters for obtaining the particle size of the particles using the Rayleigh scattering formula with the obtained particle size. ). Note that the reference particle size is set according to the design dimensions of a semiconductor (for example, a super LSI) to be manufactured. For example, the reference particle size is set to the same value or a value slightly smaller than the minimum size of the wiring and the like constituting the semiconductor.

Further, the particle size calculation unit 109 includes the area search unit 1
The intensity of the scattered light is calculated from the luminance value indicated by the high luminance pixel information from 01. Note that the relationship between the luminance value and the intensity of the scattered light is determined by an experiment or the like using a light source whose intensity is clear, and is set in the particle size calculation unit 109 in advance.

The particle size calculation unit 109 calculates the particle size of the particles using the calculated scattered light intensity and the Rayleigh scattering equation. Then, the particle size calculation unit 109 determines whether the obtained particle size is larger than the reference particle size. That is,
The particle size calculation unit 109 determines whether or not the obtained particle size is a size that causes a defect in a semiconductor to be manufactured. A production stop signal is output to 120 to stop the manufacture of the semiconductor. Note that the other functional configurations and operations of the particle monitor system are substantially the same as those of the first embodiment.

Next, the operation of the computer 100 when the particle size calculator 109 calculates the particle size will be described. First, similarly to the first embodiment, the user of the particle monitor system presses a predetermined key of the input unit 107 (keyboard) of the computer 100. By this pressing, the computer 100 sends the laser light source device 11
An irradiation signal instructing the irradiation of the laser light 140 to 0 is output, and the laser light source device 110 irradiates the laser light 140 into the process device 120.

The laser light 140 applied to the process device 120 is scattered by particles generated in the process device 120 and is emitted as scattered light 150 from the window 122 of the process device 120. Process device 120
Scattered light 150 emitted from the computer 1 is received by the scattered light detector 130 and is converted into two-dimensional image data by the computer 1.
Output to 00.

FIG. 6 is a flowchart showing the particle size calculation processing performed by the computer 100. First, as in the first embodiment, the area search unit 101 sets the scatter detector 1
The two-dimensional image data input to the computer 100 from the computer 30 is obtained (step S200).

Then, as in the first embodiment, the area search unit 101 detects the position (coordinate) and luminance value of a pixel having a luminance value equal to or greater than the threshold value, and determines the particle size as high luminance pixel information. Output to calculation section 109. The particle size calculation unit 109 calculates the intensity of the scattered light from the high luminance pixel information input from the region search unit 101 (Step S201).

Then, the particle size calculation unit 109 obtains the particle size of the particles by using the calculated intensity of the scattered light 150 and the Rayleigh scattering formula (step S202). The specific calculation will be described later. Particle size calculator 1
In step 09, it is determined whether or not the obtained particle size is larger than a previously stored reference particle size. That is, the particle size calculation unit 109 determines whether or not particles generated in the process apparatus 100 cause a defect in a semiconductor to be manufactured (step S203).

When it is determined that the obtained particle size is equal to or smaller than the reference particle size, that is, the particles generated in the process apparatus 120 do not cause a defect in the semiconductor to be manufactured (Step S).
203; NO), since the particle size calculation unit 109 does not output the production stop signal, the process apparatus 100 continues the production of the semiconductor. Therefore, the following two-dimensional image data is input from the scattered light detector 130 to the computer 100. That is, the computer 100 returns to step S200 and performs the above processing.

If the determined particle size is larger than the reference particle size, that is, if it is determined that the particles generated in the process apparatus 120 cause a defect in the semiconductor to be manufactured (step S203; YES), the particle size calculation unit 109 outputs a production stop signal to the process device 120 (step S2).
04) Stop manufacturing the semiconductor. Thus, the particle size calculation process performed by the computer 100 ends.

Next, the particle size calculation unit 109 executes step S
The calculation of the particle size performed in 202 will be described. The Rayleigh scattering formula used in the above particle size calculation is given by Equation 1.

[0092]

I ₁ = [(1 + cos ² θ) / 2 / r ² ] · [2
π / λ] ⁴ · | (m ² -1) / (m ² +2) | ² · [a
/ ^2] 6 · _{I 0}

Here, I ₀ is the intensity of the incident laser light, I ₁ is the intensity of the scattered light, θ is the angle between the incident laser light and the detected scattered light, and r is the scattered light detection point from the scattered light generation point. , Λ is the wavelength of the incident laser light, m is the refractive index, and a is the particle size of the particles.

The parameters given to the particle size calculator 109 in advance are I ₀ , θ, r, λ, and m. Then, I ₁ is obtained by the particle size calculation unit 109 as described above. However, the luminance value of the scattered light detected by the scattered light detector 130, that is, the intensity of the scattered light calculated by the particle size calculation unit 109 depends on the sensitivity of the detection system (such as the scattered light detector 130). Scattered light intensity. Therefore, a proportionality constant (S) for correcting the sensitivity of the detection system is required. This S is obtained by measuring a particle whose particle diameter is known in advance, and comparing the actual size with the measured size, and is represented by Expression 2.

[0095]

S = q · 5 / I

Here, q is the maximum luminance value of the scattered light of a standard light source (laser) having a known intensity, which is applied to particles having a known particle size, and I is the intensity of the scattered light of the standard light source.

From the above formulas and parameters, the particle size (a) of the particles generated in the process apparatus 120 can be obtained. At this time, as described above, the particle size calculation unit 109 calculates the intensity of the scattered light using the relationship obtained from an experiment or the like, and corrects the value with the proportionality constant (S). Therefore, the absolute size (particle size) of the particles generated in the process apparatus 120 can be obtained instead of the relative size.

If the particle size obtained as described above is larger than the reference particle size, the production of the semiconductor is stopped, so that the production of a defective semiconductor can be prevented.
That is, a high yield of the manufactured semiconductor can be realized.

[0099] The process apparatus 1
YAG (yt)
irradiates twice as long wave as laser
The results of measuring the particle size with the scattered light detector 130 equipped with a CCD camera are shown below. Note that each parameter is θ = 9
0 °, r = 1 m, λ = 532 nm, m = 3.48 + 2.
27i, I ₀ = 4298 W / cm ² , S = 6.2 × 10
¹⁴ . From these parameters and the above formula, it was obtained that the particle size (a) of the titanium particles generated in the process apparatus 120 was 21 nm.

FIGS. 7A and 7B are examples in which the above-described measurement of the particle size is performed during operation of the semiconductor manufacturing apparatus, and the particle size of the obtained particles is plotted. 7 (a) and 7 (b), white circles represent the particle diameters of the particles shown on the left vertical axis, and solid lines and dotted lines show the operating state of the semiconductor manufacturing apparatus shown on the right vertical axis. Is represented. FIG. 7A and FIG. 7B
The horizontal axis represents the time of the semiconductor manufacturing process.

FIGS. 7A and 7B show how the particle size of the particles generated in the process apparatus 120 during the manufacture of the semiconductor changes. The information on the particle size obtained by such measurement can be used as a clue for examining the cause of the generation of particles.

Further, the same measurement as described above is performed using various types of particles of which the size is known, so that the particle monitor system (scattered light detector 13
A particle detection limit can be obtained as to what size of particle can be detected by 0).

FIG. 8 is a diagram showing a particle detection limit of the particle monitor system. In FIG. 8, the vertical axis indicates the CCD 1 constituting the scattered light detector 130 by the scattered light.
The number of electrons generated in the pixel is shown. The horizontal axis indicates the size of the particles. The types of particles are Al (aluminum), Ti (titanium), W
(Tungsten), Al ₂ O ₃ (aluminum oxide),
And SiO ₂ (silicon dioxide). Also, CCD
Since the number of electrons generated in one pixel is proportional to the luminance value of the pixel, it can be obtained from the luminance value or the scattered light intensity.

The particle detection limit of the particle monitor system is where the actual particle size and the particle size obtained by measurement no longer match within an error range. Specifically, as shown in FIG.
The number of electrons generated in the D1 pixel decreases. If the number of electrons is smaller than a certain value (132 in FIG. 8), the scattered light 150 may not be distinguished from background noise, or an accurate particle size may not be obtained.

As described above, when the particle detection limit of the particle monitor system becomes clear, a particle monitor system having an optimum detection limit can be configured depending on the type of semiconductor to be manufactured. Also,
The semiconductor manufacturing conditions can be changed according to the particle detection limit of the particle monitor system.

When the particle generation number / size notifying unit 106 calculates the relative size of the particles, the input unit 10
Instead of the reference data input from step 7, the maximum brightness value obtained in the past measurement, the sum of the brightness values, and the number of pixels are set as reference values and compared to determine the relative size of the particles. You may.

Further, when the particle generation number / size notifying unit 106 calculates the particle size, the particle size is determined in advance by using particles whose size is known in advance instead of the reference data from the input unit 107. The obtained maximum luminance value, the sum of the luminance values, and the number of pixels may be set as reference values. In this case, the resulting particle size is representative of the actual particle size.

Further, if the number of generated particles / size notifying section 106 stores the input maximum luminance value information, total luminance value information, and information on the number of pixels as data in a memory or the like, it is generated within a certain period. You can know the size and number of particles. Therefore, statistics on the size and number of particles can be obtained, and can be used as clues to find out the cause and mechanism of generation of particles.

In the above-described pixel search processing, the input unit 10
The end signal output from 7 may be configured such that the input unit 107 also has a timer function and is automatically output after a preset time has elapsed.

In the above embodiment, the computer 100 includes the maximum brightness value detecting section 102, the total brightness value calculating section 103, and the pixel number counting section 10.
Although the case where all four functions are provided is shown, a configuration in which only one or two of these functions are provided may be adopted. Alternatively, the number of generated particles / size notifying unit 106 changes the setting of the weight used when calculating the relative size of the particles, and the maximum luminance value detection unit 102 within the region and the total luminance value calculation unit 103 within the region , And the number-of-pixels-in-region counting unit 104
May be substantially functional. However, as described above, it is more accurate to use the information from the intra-region maximum luminance value detection unit 102, the intra-region luminance value sum calculation unit 103, and the intra-region pixel number counting unit 104 in combination with each other. The relative size of the particles can be determined.

The method by which the particle generation number / size notifying unit 106 obtains the relative size of the particles is based on the maximum brightness value, the sum of the brightness values, and the size obtained from each of the number of pixels. The method is not limited to the method of calculating the average by multiplying by. For example, first, the average of the relative size obtained from the maximum luminance value and the relative size obtained from the sum of the luminance values is calculated, and the relative size obtained from the average value and the number of pixels is calculated. There is a method of taking the average of In addition, it can be appropriately changed according to the purpose and the like.

Further, the scattered light 150 of the laser light 140
Varies depending not only on the size of the particle but also on its shape. Therefore, by processing the high-brightness pixel information in consideration of the shape of the particle in advance, a more accurate particle size can be obtained.

The laser light source device 110 may be provided with a driving device to scan the laser 140 within a certain area as needed.

The display unit 108 may include a speaker or the like, display the number and size of particles on a screen or the like, and notify the user of the number and size of particles by voice.

In the second embodiment, the maximum luminance value detecting unit 102 in the area of the computer 100 transmits the maximum luminance value information indicating the detected maximum luminance value to the particle generation number / size notifying unit 106 and the particle Output to the diameter calculation unit 109,
The particle size calculation unit 109 may determine the intensity of the scattered light 150 from the maximum luminance value indicated by the maximum luminance value information input from the particle generation number / size notification unit 106. However, in the case of such a configuration, the relationship between the maximum luminance value and the scattered light intensity must be obtained in advance from experiments, theoretical expressions, and the like, and set in the particle size calculation unit 109. As described above, the absolute (actual) size of the particles can be obtained by obtaining the scattered light intensity using the relationship obtained from experiments, theoretical expressions, and the like.

The particle size calculated by the particle size calculation unit 109,
A message or the like indicating that the production stop signal has been output to the process device 120 may be displayed on the display unit 108 to notify the user of the particle monitor system.

In the second embodiment, after the particle size of the particles becomes larger than the reference particle size and the semiconductor production is stopped, the reaction by-products in the furnace are removed by heating the furnace. It may be removed. By doing so, a certain amount or more of reaction by-products can be prevented from being present in the furnace, and the generation of particles can be suppressed to a certain amount or less. As a result, a high yield of the manufactured semiconductor can be realized.

The above-described functions of the computer 100 include, for example, a program and data for performing the above-described processes stored in a recording medium (FD, CD-ROM, MO, etc.).
And distribute it, install it and install it on OS (Oper
ating System).

[0119]

As is clear from the above description, according to the present invention, simple information such as the number of pixels in the pixel area corresponding to the particle, the maximum luminance value, and the sum of the luminance values can be compared with the reference value. , The relative size of the particles can be determined. Therefore, the relative size of the particles can be obtained with a simple configuration, and the time required for obtaining the relative size of the particles can be reduced. Further, the absolute size of the particles can be obtained from the intensity of the scattered light. For this reason, if the measured particles are generated by the manufacture of the semiconductor, the manufacture of the semiconductor can be stopped if the size of the particles is large enough to cause a defect in the semiconductor being manufactured. That is, a high yield of the manufactured semiconductor can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a particle monitor system according to a first embodiment.

FIG. 2 is a diagram illustrating a state of a pixel that has detected reflected light.

FIG. 3 is a diagram illustrating a configuration of a computer that configures the particle monitor system according to the first embodiment;

FIG. 4 is a flowchart illustrating a pixel search process performed by a computer constituting the particle monitor system.

FIG. 5 is a diagram illustrating a configuration of a computer that configures a particle monitor system according to a second embodiment;

FIG. 6 is a flowchart illustrating a particle size calculation process performed by a computer configuring the particle monitor system.

FIG. 7 is a diagram showing a result of measuring a particle diameter during a semiconductor manufacturing process.

FIG. 8 is a diagram showing a result of measuring a particle detection limit of the particle monitor system.

FIG. 9 is a diagram showing a configuration of a conventional particle monitor system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 laser light source 12 scattered light detector 13 vibrating mirror 15 reaction chamber 16 introduction window 17 detection window 18 beam damper 19 particle 100 computer 101 area search unit 102 maximum brightness value detection unit 103 within area brightness value sum calculation unit 104 area pixel Number counting unit 105 Particle generation number counting unit 106 Particle generation number / size notification unit 107 Input unit 108 Display unit 109 Particle size calculation unit 110 Laser light source device 120 Process device 121 Window 122 Window 123 Absorber 130 Scattered light detector 140 Laser Light 150 Scattered light

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI H01L 21/66 H01L 21/66 JZ (56) References JP-A-5-273110 (JP, A) JP-A-11-51622 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 15/00 G01B 11/00 G01N 15/14 H01L 21/66 G01N 21/956

Claims (10)

(57) [Claims] A laser irradiating means for irradiating a laser beam to a particle monitoring target area; and a plurality of light receiving elements arranged in a matrix, and receiving scattered light of the laser light scattered by the plurality of particles. a light receiving means for outputting the image data representing the luminance values of a plurality of pixels, using the image data which the receiving means is outputted, pre
Adjacent to each other with a brightness value above the set threshold
A group of pixels to be detected is detected as a pixel region corresponding to a region where scattered light scattered by one particle enters, and the brightness of each pixel included in the pixel region is detected.
Area detection means for outputting high-brightness pixel information indicating a degree value; maximum-brightness value detection means for detecting a maximum-brightness value in the pixel region using the high-brightness pixel information; and Use the pixels in the pixel area
Pixel number counting means for counting the number of pixels, and using the high-brightness pixel information, the brightness in the pixel area.
A summing means for obtaining the sum of the values, the maximum luminance value, the number of pixels, and that of the total
And a size measuring means for measuring the relative size of the particles by comparing this with a preset reference value. 2. The image data output by the light receiving means is
Among the luminance values shown, a luminance value less than the threshold value is set to zero.
Further comprising initialization means for resetting to The area detecting means resets the luminance value by the initialization means.
Detecting the pixel area using the scanned image data
, The particle monitor according to claim 1, wherein
apparatus. 3. The area detecting means uses the image data.
Scan the pixels one by one using Brightness above threshold
When one first pixel having a value is detected, the first pixel is connected to the first pixel.
And a second image having a luminance value equal to or greater than the threshold value.
All the elements are detected, and the first pixel and the second pixel
Detecting a stop area as the pixel area.
The particle monitor device according to claim 1 or 2, wherein
Place. 4. The apparatus according to claim 1, wherein said area detecting means detects one of said pixel areas.
Every time the image data is output,
Reset means to reset the brightness value of the pixel to be reset to zero.
In addition, The area detecting means has detected one pixel area.
Thereafter, the reset unit outputs the image included in one of the pixel regions.
Each time the pixel luminance value is reset to zero, the other pixel area
Detect one area, The method according to any one of claims 1 to 3, wherein
Particle monitor device. 5. The apparatus according to claim 1, wherein said size measuring means comprises:
The number of pixels and the parameters obtained from each of the sums
Multiply the size of the article by a preset weight
The relative size of the particles
5. The method according to claim 1, wherein the magnitude is obtained.
2. The particle monitor according to claim 1. 6. The partition measured by the size measuring means.
Display means for displaying the relative size of the vehicle.
The method according to any one of claims 1 to 5, wherein
The particle monitor described in the above. 7. An apparatus according to claim 7, further comprising a counter, wherein said area detecting means includes:
Each time one pixel area is detected, the count value of the counter
Count the number of particles by incrementing
Further comprising a particle number counting means, The area detection means includes a step of determining whether the pixel area is included in the image data.
When there is no pixel information, zero information indicating that there is no pixel area is provided.
Output to the display means, The display means responds to the zero information,
Before counting by counting means Display the number of particles, The particle monitor according to claim 6, wherein
apparatus. 8. An intensity measuring means for measuring the intensity of the scattered light from the maximum luminance value detected by the maximum luminance value detecting means; an intensity of the scattered light obtained by the intensity measuring means; 2. The particle according to claim 1, further comprising: an actual measurement unit that obtains the absolute size of the particle using a relational expression indicating a relationship between the intensity of the particle and the absolute size of the particle. Monitor device. 9. A laser irradiation step of irradiating a laser beam to a particle monitoring target area; and using a plurality of light receiving elements arranged in a matrix, the scattered light of the laser light scattered by the plurality of particles is used. receiving and using a light receiving step of outputting the image <br/> image data indicating the luminance values of a plurality of pixels, the image data outputted by the light receiving step,
Adjacent to each other having a brightness value equal to or higher than a preset threshold
A group of adjacent pixels is detected as a pixel region corresponding to a region where scattered light scattered by one particle is incident, and each pixel included in the pixel region is detected .
An area detection step of outputting high-brightness pixel information indicating a brightness value, a maximum-brightness value detection step of detecting a maximum brightness value in the pixel area using the high-brightness pixel information, Use the pixels in the pixel area
Using the high-brightness pixel information to count the number of pixels in the pixel area
A summing step of obtaining a sum of values, the maximum luminance value, the number of pixels, and that of the total
Les and by comparing with a predetermined reference value, the particle monitoring method characterized by comprising a size measuring step of measuring the relative size of the particles, the. 10. A computer, Multiple light-receiving elements arranged in a matrix
Receive scattered light scattered by a number of particles
Image data output from the receiver and indicating the luminance values of a plurality of pixels
Brightness value above a preset threshold
A group of adjacent pixels having
Scattered light scattered by one particle is incident
Detected as a pixel area corresponding to the area, and included in the pixel area
Output high-luminance pixel information indicating the luminance value of each pixel
Area detection means; Using the high brightness pixel information, the maximum within the pixel area
Maximum luminance value detecting means for detecting a luminance value, Using the high brightness pixel information, the pixels in the pixel area
Pixel number counting means for counting the number, Using the high brightness pixel information, the brightness in the pixel area
Summing means for calculating the sum of the values; Each of the maximum luminance value, the number of pixels, and the sum
By comparing it with a preset reference value.
Size measuring means for measuring the relative size of articles
When, To function as a particle monitor device equipped with
Computer with recorded programs and data
Recording media.