JP2000097886A - X-ray fluorescence analyzer - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide an X-ray fluorescence spectrometer that uses a wafer housed in a cassette as a sample and that can perform mapping for a plurality of types of cassettes having different sizes and shapes. Kind Code: A1 A type of a loaded cassette is input, and a cassette table on which the cassette is mounted is set in a predetermined direction by a rotating means according to the type, and a lifting means is provided.
Control for obtaining the stored height of the wafer 1 in the loaded cassette 6 based on the detection signal from the detecting means 21 for detecting the cassette 6 or the wafer 1 in the predetermined detection height and direction in the predetermined detection height and direction. Means 28 are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray fluorescence analyzer for measuring the intensity of X-ray fluorescence generated by irradiating a sample with primary X-rays, and particularly to an apparatus using a wafer stored in a cassette as a sample. It is about.

[0002]

2. Description of the Related Art Conventionally, contamination analysis of a semiconductor wafer has been performed using a so-called fluorescent X-ray analyzer.
The wafer is disk-shaped, 6 inches, 8 inches, 300 mm (1
There are various diameters such as 2 inches), each of which is stored in a cassette having a predetermined size and shape according to the diameter of the wafer and handled. Here, as shown in FIG. 5, the cassette 6 is formed with a number of shelves for storing the wafers 1 one by one inside the left and right side walls 6c.
The 8-inch cassettes 6A and 6B can store up to 25 wafers, and the 300-mm cassette 6C holds one wafer.
Although up to three wafers can be stored, the number of stored wafers 1 and the storage positions of the cassettes 6 storing the wafers 1 to be analyzed are usually different for each cassette 6.

Therefore, when the cassette 6 is loaded into the apparatus and placed on the cassette table, the stored wafers 1 are loaded and unloaded one by one by the robot hand and analyzed on the sample table. It is necessary to determine the number of the shelf in the cassette 6, in other words, for example, the height of the cassette 6 from the upper surface of the cassette table. This is called mapping of the wafer 1 in the cassette 6. Further, in order to load and unload the wafer 1 from the open front surface (entrance / exit) 6a of the cassette 6, the cassette 6 needs to be positioned and placed on the cassette table so that the entrance / exit 6a of the cassette 6 faces the robot hand. There is also.

On the other hand, since the size and shape of the bottom of the cassette 6 are determined in accordance with the size of the cassette 6, that is, the diameter of the wafers 1 to be stored, conventionally, an adapter corresponding to the size and shape of the bottom is conventionally used. Was applied to a common cassette table, and the cassettes 6 of each size were positioned and mounted. Then, for example, in the cassette chamber into which the cassette 6 is loaded, the cassette 6 is detected in a predetermined horizontal detection direction.
The LED and the optical sensor opposed to each other are moved up and down, and the light from the LED is blocked on the side surface of the wafer 1 to detect the wafer 1 and perform mapping.

[0005]

However, in this conventional apparatus, unless an appropriate adapter is selected and used for each size of the cassette 6, it cannot be positioned and mounted on the cassette table, and the analysis procedure becomes complicated. Become. Further, although the basic shape of the cassette 6 is defined by the standard according to the size, the light of the horizontal LED is opposed to the height of the cassette 6 without the wafer 1 without being blocked by the side wall 6c of the cassette 6. The direction in which the optical sensor reaches the optical sensor is not always the same depending on the size of the cassette 6 and the difference in shape between manufacturers even if the size is the same. That is, the detection direction suitable for detecting the stored wafer 1 cannot be unified for a plurality of types of cassettes 6, and if the detection direction is determined corresponding to a certain type of cassette 6, the size and shape may differ. In some cases, the side wall 6c of the cassette 6 is detected and mapping cannot be performed on the cassette 6 of the type.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. In a fluorescent X-ray analyzer using a wafer stored in a cassette as a sample, mapping is performed even for a plurality of types of cassettes having different sizes and shapes. It is an object of the present invention to provide a device capable of performing such operations.

[0007]

In order to achieve the above object, an X-ray fluorescence spectrometer according to claim 1 uses a plurality of wafers having a predetermined diameter as a sample, and uses one of the predetermined diameters as a sample. A cassette chamber into which a predetermined type of cassette containing wafers is loaded, and positioning means provided in the cassette chamber for positioning the cassette at a predetermined position in accordance with the diameter of the stored wafers; And a cassette table to be placed.

The apparatus further comprises a rotating means for rotating the cassette table, an elevating means for elevating the cassette table, and detecting a cassette or a wafer at a predetermined detection height and direction in the cassette chamber. It comprises a detecting means and the following control means. When the type of the loaded cassette is input, the control unit sets the cassette table in a predetermined direction by the rotation unit according to the type, moves the cassette table up and down by the lifting unit, and outputs a detection signal from the detection unit. Then, the stored height of the wafer in the loaded cassette is obtained based on the above.

According to the first aspect of the present invention, the cassette table comprises:
Since there is a positioning means for positioning the cassette at a predetermined position according to the size, cassettes of each size can be positioned and mounted on a single cassette table without using an adapter or the like. Then, the control means rotates the cassette table in accordance with the type of the input cassette by the rotating means, sets the wafer in a predetermined direction suitable for detecting the wafer by the fixed detecting means, and sets the cassette in the elevating means. Since the mapping is performed based on the detection signal from the detection means by moving the table up and down, mapping can be performed on a plurality of types of cassettes having different sizes and shapes.

The X-ray fluorescence analyzer according to the second aspect is different from the first aspect only in the content of the control performed by the control means. That is, the control means of the apparatus according to claim 2 sets the cassette table at a predetermined height by the elevating means, rotates the cassette table by the rotating means, and based on the detection signal from the detecting means, The wafer is set in an appropriate direction for detection, is moved up and down by the elevating means, and the stored height of the wafer in the loaded cassette is obtained based on a detection signal from the detecting means.

According to the apparatus of claim 2, first, claim 1
In the same manner as in the above device, cassettes of each size can be positioned and mounted on a single cassette table without using an adapter or the like. Then, the control means sets the cassette table at a predetermined height by the elevating means, rotates it by the rotating means, and detects a wafer by the fixed detecting means based on a detection signal from the detecting means. After setting the direction, the cassette table is moved up and down by the elevating means and mapping is performed based on the detection signal from the detecting means, so there is no need to input the type of the loaded cassette, and multiple types of cassettes with different sizes and shapes Can be mapped to

According to a third aspect of the present invention, there is provided an X-ray fluorescence analyzer.
In the apparatus described above, the control means further obtains the diameter of the wafer in the loaded cassette. According to the apparatus of the third aspect, the control means can convert the interval of the detection signal at the time of mapping into the height interval of the stored wafers and calculate the pitch of the cassette shelf based on the converted interval. The diameter of the wafer stored in the cassette is automatically obtained without inputting the data, so that the operation necessary for the analysis such as the subsequent movement of the wafer to the sample table by the robot hand is smoothly performed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus according to a first embodiment of the present invention will be described below. First, the configuration of this device will be described. As shown in the plan view of FIG. 2, the apparatus includes a sample table 2 on which a sample wafer 1 is mounted, an X-ray source 4 such as an X-ray tube for irradiating the sample 1 with primary X-rays 3, And a detecting means 5 such as an SSD for measuring the intensity of the fluorescent X-rays generated from the device 1. This apparatus is a so-called total reflection X-ray fluorescence spectrometer, in which primary X-rays 3 are incident on the surface of the wafer 1 almost in parallel at a small incident angle, and the detecting means 5 is installed above the wafer 1.

This apparatus uses a 6-inch, 8-inch, or 300-mm wafer 1 as a sample and stores the wafer 1 in a 6-inch, 8-inch, or 30-mm size.
The cassette 6 having a size of 0 mm is carried into the cassette chamber 7. A robot hand 8 for carrying in / out the wafers 1 one by one from the entrance / exit (opened, left side surface perpendicular to the paper surface) 6a of the cassette 6 between the sample stage 2 and the cassette chamber 7.
It has. X-ray source room 1 in which the front part of X-ray source 4 is stored
0, the cassette chamber 7 communicates with the sample table 1 and the sample chamber 9 in which the robot hand 8 is provided, and the pressure is reduced by a pressure reducing means such as a vacuum pump (not shown). When the pressure in the cassette chamber 7 is reduced, the lid 11 is closed. It should be noted that the X-ray source chamber 10 and the sample chamber 9 are shown in cross section, and the housings and the like of the devices further outside the chambers 10, 7, 9 are not shown.

FIG. 1 is a side view showing the vicinity of the cassette chamber 7.
The cassette chamber 7 includes a cylindrical side wall 12, a bottom 13, and the lid 1.
1, a cassette table 14 on which the cassette 6 is placed is provided. In addition, the side wall 12, the bottom part 13, and the lid 11 are shown in cross sections. As shown in FIG. 3, which is a view in the direction of arrow A in FIG. 1, the cassette table 14 has a substantially square plate shape, and positioning means for positioning the cassette 6 at a predetermined position according to its size, as will be described later. That is, the positioning blocks 15, 16, 17 and the positioning pins 18 are screwed.

As shown in FIG. 1, this apparatus comprises a rotating means 19 for rotating the cassette table 14, an elevating means 20 for raising and lowering the cassette table 14, and a predetermined detection height and a predetermined detection direction in the cassette chamber 7. , Detecting means 21 for detecting a cassette or a wafer. Rotating means 19
Comprises a rotating shaft 22 and a slider moving unit 23. A rotating shaft 22 that extends vertically downward is fixed to the center of the cassette table 14, and the rotating shaft 22 is supported by the cassette chamber bottom 13 via a bearing 24 so as to be rotatable and vertically movable above the cassette shaft 14,
Below, it is rotatably supported near one end of the slider moving part 23.

A motor is built in the vicinity of the other end of the slider moving section 23, and rotates the rotary shaft 22 via a belt or the like. The elevating means 20 uses a so-called slider unit, and includes a slider moving portion 23 and a slider fixing portion 24. The slider fixing portion 24 is moved along the rail 24a by a built-in motor, a ball screw, or the like.
Is raised and lowered in the vertical direction. The slider fixing portion 24 is connected to the cassette chamber bottom 1 via a back plate 24b and a frame 25.
3 and the cassette chamber bottom 13 is fixed to the frame of the entire apparatus.

The detecting means 21 comprises an LED 26 and an optical sensor 27, and is installed outside the cassette chamber 7 at a predetermined detection height and a predetermined detection direction in the cassette chamber 7. The light from the LED 26 is transmitted to the cassette chamber side wall 12.
If the light passes through the transparent window 12a and is not blocked by the cassette 6 or the wafer 1, the light passes through the opposite window 12a and is received by the optical sensor 27. That is, the cassette 6 or the wafer 1 is detected when the optical sensor 27 does not receive light.

Further, this apparatus has the following control means 28
It has. The control means 28 sets the cassette table 14 at a predetermined height by the elevating means 20, rotates the cassette table 14 by the rotating means 19, and based on the detection signal from the detecting means 21,
The direction is set so that the detection means 21 can detect the wafer 1. Then, the cassette table 14 is moved up and down by the elevating means 20, and based on the detection signal from the detecting means 21, the height and diameter of the loaded cassette 6 in which the wafer 1 is stored are obtained.

Next, the operation of this device will be described.
Before the cassette 6 is loaded, the cassette table 14 is located at a height immediately below the lid 11 of the cassette chamber 7, for example, in the direction shown in FIG. 3 (the upper side in FIG. 3 is the sample chamber 9 side in FIG. 2). It is suitable. When loading the cassette 6, the lid 11 is opened, and a 6-inch, 8-inch, or 300 mm-size cassette 6 containing the wafer 1 to be analyzed is placed on the cassette table 14. Here, for example, the bottom surface of the 8-inch size cassette 6B has a shape as shown by hatching in the bottom view of FIG. 6, whereas the bottom surface of the four positioning blocks 15B of the cassette table 14 of FIG.
Ba contacts to position in the left-right direction in FIG. 3, and the contact surfaces 17a of the two positioning blocks 17 contact to perform positioning in the vertical direction.

In the case of a 6-inch cassette 6A,
Since the bottom is a little smaller with the same shape as the 8-inch size,
Vertical positioning is done in the same way as 8 inch size,
The positioning in the left-right direction is performed by four positioning blocks 15A,
The contact surfaces 15Aa and 16a are provided. 300mm
In the case of the cassette 6C having the size, V-grooves which are substantially oriented toward the center are provided at three places on the bottom, and the positioning is performed by three positioning pins 18 corresponding to the V-grooves (in the direction B in FIG. (See FIG. 4 which is an arrow view). Thus, according to the apparatus of the first embodiment, the cassette table 14
Since there are positioning means 15, 16, 17, and 18 for positioning the cassette 6 at a predetermined position in accordance with the size, the cassette 6 of each size can be set on the single cassette table 14 without using an adapter or the like. It can be positioned and mounted on the table 14.

When the cassette 6 is placed on the cassette base 14 and a message to the effect that mapping is to be performed is input, the control means 28 first lowers the cassette base 14 by the elevating means 20 to a predetermined height. Set. This predetermined height means that, regardless of the size of the loaded cassette 6 or the difference in shape depending on the manufacturer, if the cassette 6 is appropriately rotated at that height, the light from the LED 26 will cause the wafer The height of the cassette table 14 which is received by the optical sensor 27 without being interrupted.

The predetermined height is usually such that the lower part of the lowermost shelf of the cassette 6 comes to the detection height of the detection means 21 (the height indicated by a dashed line in FIG. 1). You can decide beforehand. In order to determine the predetermined height, if necessary, a positioning pin 18 (FIG. 4) on which a V-groove on the bottom of the 300 mm cassette 6C is placed.
30 when placed on the cassette table 14 with the height of
It is also possible to adjust the height of the 0 mm cassette 6C from the upper surface of the cassette table. At this stage, the pressure in the cassette chamber 7 can be reduced by closing the lid 11.

Next, the control means 28 rotates the cassette table 14 by the rotation means 19 and sets the direction to an appropriate direction for detecting the wafer 1 by the detection means 21 based on the detection signal from the detection means 21. . Specifically, the light from the LED 26 irradiating the direction in which the optical sensor 27 receives light, that is, the light slightly lower than the lowest shelf of the cassette 6 is received by the optical sensor 27 without being blocked by the cassette 6. The rotation of the cassette table 14 is stopped in the direction shown in FIG. The appropriate direction of the cassette table 14 usually means the entrance 6a of the loaded cassette 6 and the opening 6b on the rear surface facing the entrance 6a.
(FIG. 2) is a direction penetrated in the detection direction of the detection means 21.

The control means 28 controls the cassette table 14
Is lowered by the elevating means 20, and the stored height of the wafer 1 in the loaded cassette 6 is obtained based on the detection signal from the detecting means 21. More specifically, if the wafer 1 comes to the detection height of the detection means 21 by lowering the cassette table 14, the wafer 1 is blocked by the wafer 1 and the light sensor 27 stops receiving light. The height at which the wafer 27 is not received is determined as the height at which the wafer 1 is stored in the loaded cassette 6.

If the time during which the optical sensor 27 does not receive light is longer than the time corresponding to the thickness of the wafer 1, since the cassette 6 has been detected, the lowering of the cassette table 14 is stopped, and the mapping is terminated. . As described above, according to the apparatus of the first embodiment, after the cassette table 14 is set by the control unit 28 or the like in an appropriate direction for detecting the wafer 1 by the fixed detection unit 21, mapping is performed. Therefore, mapping can be performed for a plurality of types of cassettes 6 having different sizes and shapes without inputting the type of the loaded cassette 6.

Further, the control means 28 not only obtains the stored height of the wafer 1 in the loaded cassette 6 but also detects the detection signal from the detection means 21 when the cassette table 14 is lowered by the lifting / lowering means 20. The diameter of the wafer 1 is obtained based on More specifically, if the pitch of the shelves of the cassettes 6 of each size is previously input to the control means 28, the height of the wafer 1 in which the interval of the detection signal indicating that the optical sensor 27 does not receive light during mapping is stored. A cassette 6 having a pitch of shelves that is converted into an interval and is a common divisor
, That is, the diameter of the stored wafer 1. Therefore, the diameter of the wafer 1 stored in the cassette 6 is automatically obtained without inputting the type of the loaded cassette 6, and the robot hand 8 shown in FIG. Operations required for analysis such as movement are smoothly performed.

As described above, when the height at which the wafer 1 is stored and the diameter of the wafer 1 in the loaded cassette 6 are obtained, the control means 28 controls the entrance 6 of the cassette 6
a so that the rotation means 19a faces the robot hand 8.
The cassette table 14 (FIG. 1) is rotated in (FIG. 1). Then, for example, the elevating means 20 is set to a height suitable for carrying out the uppermost wafer 1 from the entrance 6a by the robot hand 8.
The cassette table 14 (FIG. 1) is raised (FIG. 1), the wafer 1 is moved to the sample table 2 by the robot hand 8, the primary X-rays 3 are radiated from the X-ray source 4, and the detection unit 5 is moved. The measurement of the intensity of the fluorescent X-rays in step S1 and the accommodation in the cassette 6 by the robot hand 8 are performed. Thereafter, the procedure from the raising of the cassette table 14 (FIG. 1) by the lifting / lowering means 20 (FIG. 1) to the storage in the cassette 6 is repeated in the descending order of the position, and the analysis of each wafer 1 is performed.

It is to be noted that whether or not the wafer 1 has been unloaded from the cassette 6 by the robot hand 8 and stored in the cassette 6 has been normally determined by raising and lowering means so that the stored position of the wafer 1 is at the detection height. At 20 (FIG. 1), the cassette table 14 (FIG. 1) can be moved up and down for confirmation. Here, in the apparatus of the first embodiment, since the wafer 1 is detected in the cassette chamber 7 which is decompressed and communicates with the sample chamber 9, whether or not the loading and unloading of the wafer 1 is normally performed quickly while maintaining the vacuum atmosphere. Can be checked, and the loading and unloading can be performed again. When the analysis of each wafer 1 is completed, the pressure in the cassette chamber 7 is released, the lid 11 is opened, and the lid 11 is opened immediately below the lid 11 when the cassette table 14 (FIG. 1) is closed by the lifting / lowering means 20 (FIG. 1). Can be raised to height. The operator unloads the cassette 6 from the apparatus.

Next, an apparatus according to a second embodiment of the present invention will be described. This device differs from the device of the first embodiment only in the content of the control performed by the control means 38. The control means 38 of the apparatus according to the second embodiment shown in FIG.
Is input, the cassette table 1 is set according to the type.
4 is set in a predetermined direction by the rotating means 19, moved up and down by the elevating means 20, and based on the detection signal from the detecting means 21, the stored height of the wafer 1 in the loaded cassette 6 is obtained.

That is, for this apparatus, it is necessary to input the type of the cassette 6 to be carried in at the time of mapping, and the control means 38 controls the cassette table 1 according to the type.
4 is set in a predetermined direction by the rotating means 19. The predetermined direction is a direction suitable for detecting the wafer 1 by the detection unit 21 described above. In the apparatus of the first embodiment, the control unit 28 finds this, but in the apparatus of the second embodiment, Are input to the control means 38 in advance for each type of the cassette 6. As described above, the appropriate direction for detecting the wafer 1 by the detecting means 21 may be different depending on the shape of the cassette 6 even if the size of the cassette 6 is the same. It is necessary to sort them in consideration of the difference in shape between different sizes and manufacturers.

After or while setting the cassette table 14 in a predetermined direction, the control means 38 controls the cassette table 1
4 is lowered by the elevating means 20 so that the predetermined height at which the detection of the wafer 1 is to be started, for example, a height at which the lower part of the lowermost shelf of the cassette 6 comes to the detected height of the detecting means 21. Set to Thereafter, similarly to the control unit 28 of the device of the first embodiment, the control unit 38 of the device of the second embodiment
Moves the cassette table 14 down by the elevating means 20, finds the stored height of the wafer 1 in the loaded cassette 6 based on the detection signal from the detecting means 21, and performs mapping.

As described above, according to the apparatus of the second embodiment, first, similarly to the apparatus of the first embodiment, the cassettes 6 of each size are stored on the single cassette table 14 without using an adapter or the like. Can be positioned and placed. The control means 38 rotates the cassette table 14 by the rotation means 19 in accordance with the type of the input cassette 6, and sets the wafer 1 in a predetermined direction suitable for detection by the fixed detection means 21. Since mapping is performed, mapping can be performed on a plurality of types of cassettes 6 having different sizes and shapes. In addition, it is possible to quickly confirm whether or not the wafer 1 has been properly loaded / unloaded into / from the cassette 6 while maintaining the vacuum atmosphere, and to carry out the loading / unloading again, similarly to the apparatus of the first embodiment. is there.

[0034]

As described above in detail, according to the present invention, a fluorescent X-ray sample using a wafer stored in a cassette as a sample is provided.
In a line analyzer, mapping can be performed on a plurality of types of cassettes having different sizes and shapes.

[Brief description of the drawings]

FIG. 1 is a side view of the vicinity of a cassette chamber of a fluorescent X-ray analyzer according to first and second embodiments of the present invention.

FIG. 2 is a plan view of the same device.

FIG. 3 is a view in the direction of arrow A in FIG. 1;

FIG. 4 is a view in the direction of arrow B in FIG. 1;

FIG. 5 is a perspective view showing a cassette containing wafers.

FIG. 6 is a bottom view of an 8-inch cassette.

[Explanation of symbols]

1. Wafer (sample), 2. Sample table, 3. Primary X-ray, 6.
Cassette, 7: cassette room, 14: cassette stand, 15,
16, 17, 18 positioning means, 19 rotating means, 2
0: elevating means, 21: detecting means, 28, 38: controlling means.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G001 AA01 BA04 CA01 GA13 JA08 JA09 JA12 JA14 JA20 KA01 LA11 MA05 PA01 PA07 PA11 PA12 PA14 PA16 PA30 QA01 4M106 AA01 BA20 CA29 DG02 DG03 DG05 DG16 DG28 DH01 5F031 CA02 HA58 JA59 MA33 PA16

Claims (3)

[Claims] 1. An X-ray fluorescence analyzer for measuring the intensity of X-ray fluorescence generated by irradiating a sample placed on a sample stage with primary X-rays, wherein a plurality of wafers having a predetermined diameter are used as samples. A cassette chamber into which a cassette of a predetermined type in which a wafer of one of the predetermined diameters is stored is loaded, and the cassette is provided in the cassette chamber and is positioned at a predetermined position in accordance with the diameter of the stored wafer. A cassette table on which a cassette is placed, a rotating means for rotating the cassette table, an elevating means for elevating and lowering the cassette table, a predetermined detection height in the cassette chamber and In the detection direction, a detection means for detecting a cassette or a wafer, and a type of the loaded cassette are input, and the cassette table is moved in a predetermined direction by the rotating means according to the type. X-ray fluorescence spectrometer, comprising: a control unit for determining the height at which wafers are stored in a cassette loaded based on a detection signal from the detection unit. . 2. An X-ray fluorescence analyzer for irradiating a sample placed on a sample stage with primary X-rays to measure the intensity of X-ray fluorescence generated, wherein a plurality of wafers having a predetermined diameter are used as samples. A cassette chamber into which a cassette of a predetermined type in which a wafer of one of the predetermined diameters is stored is loaded, and the cassette is provided in the cassette chamber and is positioned at a predetermined position in accordance with the diameter of the stored wafer. A cassette table on which a cassette is placed, a rotating means for rotating the cassette table, an elevating means for elevating and lowering the cassette table, a predetermined detection height in the cassette chamber and A detecting means for detecting a cassette or a wafer in a detecting direction; and setting the cassette table at a predetermined height by the elevating means, rotating by the rotating means, Based on the detection signal, the direction is set to an appropriate direction for detecting the wafer by the detection means, the wafer is moved up and down by the elevating means, and the wafer stored in the cassette carried in based on the detection signal from the detection means. An X-ray fluorescence spectrometer comprising: a control unit for obtaining a height. 3. The X-ray fluorescence analyzer according to claim 2, wherein the control unit further obtains a diameter of a wafer in the loaded cassette.