JP3502915B2 - Glow discharge emission spectrometer - Google Patents

Description

BACKGROUND OF THE INVENTION [0001] [Technical Field of the Invention The present invention, while sputtering of the sample, the generated light relates glow discharge optical emission spectroscopy min 析装 location to be analyzed by a spectrometer. 2. Description of the Related Art When a DC or high-frequency high voltage is applied between two electrodes in an argon (Ar) atmosphere at a gas pressure of about 500 to 1300 Pa, a glow discharge occurs.
Ar ions are generated. The generated Ar ions are accelerated by a high electric field, collide with the surface of the cathode, and knock out substances existing there. This phenomenon is called sputtering, and the sputtered particles (atoms, molecules, ions) are excited in the plasma and emit light having a wavelength specific to the element when returning to the ground state. An analysis method in which the emitted light is spectrally separated by a spectroscope to identify the element is called a glow discharge emission spectral analysis method. In this glow discharge emission spectroscopic analysis method, a hollow anode type grim glow discharge tube is generally used. In the glow discharge tube, the inner space in which the anode tube is housed is evacuated, and the anode tube and the sample are removed. A glow discharge is generated by applying a voltage between the samples, and the generated light is analyzed by a spectroscope while sputtering the sample. Here, since the inner surface and the tip surface of the anode tube are contaminated by sputtering, before analysis, the inner surface and the tip surface of the anode tube are cut and cleaned with a drill or a stepped reamer after the analysis. .
This cleaning operation is performed regularly or every time before the analysis. [0004] Here, in order to prevent the anode tube from being damaged by a reamer or the like, a clearance is required at a contact surface with the anode tube. The outer diameter of the reamer or the like is larger than the inner diameter of the anode tube. Is also set small, so that the step portion of the reamer is not excessively pressed against the tip end surface of the anode tube. Therefore, unlike the flat tip surface of the anode tube, which has a small area, the inside surface of the anode tube, which has a large area and is a curved surface, is not contaminated even if the cleaning operation using the conventional stepped reamer or the like is performed every time before the analysis. Cannot be removed sufficiently. This unremovable stain causes the background of the next analysis, etc., and it is difficult to analyze sufficiently accurately, especially when analyzing a sample of a different type from the previous one or when precisely analyzing the outermost layer. Met. [0005] The present invention, contamination of the inner surface of the anode tube can be sufficiently removed, it is an object to provide a glow discharge optical emission spectroscopy min 析装 location that can more accurate analysis. [0008] In order to achieve the above object,
The glow discharge optical emission spectrometer according to claim 1 , further comprising: a glow discharge tube having an anode tube; a decompression means for evacuating an inner space in which the anode tube is housed; A power supply means for applying a voltage to generate a glow discharge, a substantially cylindrical brush having a number of flexible branches having spherical abrasive grains at a tip for polishing the inner surface of the anode tube, and In a glow discharge optical emission spectrometer equipped with automatic cleaning means for polishing the inner surface of the anode tube using the brush, provided with a plurality of brushes according to the inner diameter of the anode tube, the automatic cleaning means, The brush is selected according to the inner diameter of the anode tube used for analysis. According to the device of claim 1, the brush makes the brush positive.
Polished properly without damaging the inner surface of the electrode
As a result, dirt on the inner surface of the anode tube can be sufficiently removed,
Accurate analysis can be performed. Moreover, it can be used as an automatic cleaning means
Thus, the effect can be easily obtained. Further
In addition, such a configuration can cope with a case where the inner diameter of the anode tube used for analysis is changed. DETAILED DESCRIPTION OF THE INVENTION Hereinafter, will be described glow discharge optical emission spectroscopy min 析装 location of an embodiment of the present invention. In this device, as shown in FIG. 3, light S emitted from a grim glow discharge tube 1 that generates light having a wavelength specific to an element by sputtering using a glow discharge and transmitted through a window 13a.
Enters the spectroscope 13. The spectroscope 13 has a window 13a
In addition, an incident slit 24, a diffraction grating 26 for diffracting the light S incident from the incident slit 24 at different diffraction angles according to the wavelength, an exit slit 27 for transmitting the diffracted light, and a photoelectron for measuring the intensity of the diffracted light A multiplier tube 28 is provided. [0010] Further, this device is used as a glow discharge tube.
A hollow anode type grim glow discharge tube 1 as shown in FIG. 4 is used. In the grim glow discharge tube 1, a support block (a support portion to which the sample 6 is brought into contact, which is also a cathode in the present embodiment) 2 and an anode block 3 are connected via a Teflon washer 4 as an insulating portion. Are joined. The anode block 3 is integrally formed with a hollow anode tube 3d. The anode tube 3d penetrates the Teflon washer 4 and is close to the analysis surface (surface) 6a of the sample 6. The sample 6 is pressed against the support block 2 in an airtight manner via a sealing member 11 such as an O-ring having a ring shape surrounding a portion to be analyzed on the analysis surface 6a. Note that, in the present invention, the glow discharge tube is not limited to the structure as in this embodiment, and the supporting portion to which the sample comes into contact is an insulating portion, and the sample is sandwiched between the supporting portion and the cathode block. It may be of such a structure. Further, in the present embodiment, the sample 6 is illustrated as a substantially disk-shaped one such as a semiconductor wafer, but the application of the present invention is not limited to such a sample. Thus, the inner space (glow discharge space) of the support block 2 for accommodating the hollow anode tube 3d by the sample 6.
The opening of V is sealed, and the inner space V is evacuated from the first and second evacuation holes 3b and 3c by an evacuation device (decompression means) (not shown). Further, the anode block 3 has an argon gas supply hole 3a, and the tube V has a rare gas atmosphere of argon (500 to
1300 Pa). The glyme glow discharge tube 1 includes an anode tube 3d
A high voltage is applied by a power supply unit (power supply means) 12 between the anode 6 and the support 6 through the anode block 3 and the support block 2 to generate a glow discharge, and the sample 6 passes through the support block 2 which is generally made of copper. A negative voltage is applied to the sample and the sample 6 is sputtered by causing cations of argon generated by the generation of glow discharge to collide with the analysis surface 6a of the sample. Further, the sample 6 and the hollow anode tube 3d are cooled through the support block 2 by introducing the coolant K from the coolant introduction passage 2a of the support block 2 into the jacket 2b and feeding it to the coolant discharge passage 2c. are doing. [0013] Further, the apparatus has an inner surface 3 of the anode tube 3d.
In order to polish f, a brush cleaning tool 18B to which a brush 30 having a substantially cylindrical shape as shown in the front view of FIG. This brush 30 is shown in FIG.
As shown in the plan view of FIG.
Have a plurality of flexible branches 30b spirally around the axis 30a. Here, the spherical abrasive grains 30c are, for example, silicon carbide, the branches 30b are, for example, nylon resin, the shaft 3
Oa is preferably made of, for example, stainless steel. FIG.
In (a), the outer diameter of the brush 30 (the spherical abrasive grains 30 c
Is set to be slightly larger than the inner diameter of the anode tube 3d (FIG. 4). The brush 30 is attached to a substantially cylindrical holder 31, and constitutes a brush cleaning tool 18B as a whole. Specifically, first, the lower part of the brush body 30d is housed in the hole 31b at the upper part of the holder 31, and the shaft 3 having no spherical abrasive grains 30c below the brush body 30d.
The mounting portion 30e, which is the portion of 0a, is passed through the hole 31c at the lower part of the holder 31. The lower left side of the holder 31 is separated from the upper side, and a pair of flanges 31e and 31f (only one side 31e is shown) are formed in the direction perpendicular to the paper across the slit 31d. By screwing a bolt 31g for pinching through the through hole formed in the other side 31e, the attachment portion 30e of the brush passed through the hole 31c is tightened, and the brush 30 is detachably attached to the holder 31. Further, this apparatus is provided with a stepped reamer 32 as shown in FIG. 1 for cutting the inner surface 3f and the tip surface 3e of the anode tube 3d in FIG. A reamer cleaning tool 18A is also provided.
Brush cleaning tool 18B, reamer cleaning tool 1
8A is held in a stocker 17 provided on the right side of the glow discharge tube 1 when it is not used. The stocker 17 is set at the height indicated by the one-dot chain line in FIG.
The spring plunger 10 for detachably attaching the brush cleaning tool 18B is attached to the shaft 30a of the brush cleaning tool 18B in the circumferential direction as shown in FIG.
I have one. Here, the spring plunger 10 is formed by projecting a ball 10a pressed by an internal spring from an open end of a cylindrical case. On the other hand, the holder 31 of the brush cleaning tool 18B has a V-shaped engagement groove 31a on its upper outer periphery for engaging with the ball 10a. Similarly, the stocker 17 has a spring plunger 10 (FIG. 2) for removably attaching a reamer cleaning tool 18A to a height indicated by a dashed line in FIG.
(A)) in the circumferential direction about the axis of the reamer cleaning tool 18A.
The holder 33 of A also has a V-shaped engagement groove 33a. Furthermore, this apparatus uses a robot hand (automatic cleaning means) for cutting or polishing the inner surface 3f and the tip surface 3e (FIG. 4) of the anode tube using the stepped reamer 32 and the brush 30 before analysis. ) 15. The robot hand 15 includes a base 15a extending left and right below the glow discharge tube 1 and the stocker 17, a horizontal moving body 15b moving left and right with respect to the base 15a, and a vertical moving body 15c moving up and down with respect to the horizontal moving body 15b. ,
It includes a rotating body 15d that rotates with respect to the vertically moving body 15c, and a hand unit 15e that is provided at the tip of the rotating body 15d and that opens and closes and grips the reamer cleaning tool 18A and the brush cleaning tool 18B. Horizontal moving body 15b,
The vertical moving body 15c and the rotating body 15d are driven horizontally and vertically by, for example, a ball screw connected to a pulse motor, an air cylinder, and a belt interlocked with the pulse motor 15f, and rotated. In addition, the hand part 15e is formed in a shape that can easily hold the holders 31 and 33 of the cleaning tools 18A and 18B. Next, the operation of this device will be described. Now, it is assumed that the sample 6 has been removed from the support block 2 of the glow discharge tube 1 after the previous analysis has been completed. Before the next analysis, when the input means (not shown) indicating that cleaning of the anode tube 3d should be performed is input to this apparatus,
The robot hand 15 moves the hand unit 15e from the initial state shown in FIG. 1 to a position below the reamer cleaning tool 18A held by the stocker 17, raises the reamer cleaning tool 18A, and holds the reamer cleaning tool 18A with the hand unit 15e ( 1 (shown by a two-dot chain line at the upper right in FIG. 1), and is pulled downward. Thus, the spring plunger ball 10a (FIG. 2)
(A) is pushed outward by the outer peripheral surface above the engagement groove 33a of the holder 33, the engagement is released, and the reamer cleaning tool 18A is removed from the stocker 17. The robot hand 15 moves the reamer cleaning tool 18A thus removed to a position below the anode tube 3d while holding it with the hand portion 15e, and raises it while rotating it so that the upper part of the stepped reamer 32 becomes anode. Tube 3d
Then, the stepped portion is brought into contact with the front end face 3e of the anode tube in FIG. 4, and the inner surface 3f and the front end surface 3e of the anode tube are cut. Here, the hand portion 15e of the robot hand of FIG. 1 and the support block 2 which is the lower part of the glow discharge tube 1 are formed in shapes that do not interfere with each other. Reamer cleaning tool 1
After rotating 8A for a predetermined time, the robot hand 15
The hand portion 15e is lowered to pull out the stepped reamer 32 from the anode tube 3d, and in conjunction with this, argon gas is flushed from the argon gas supply hole 3a (FIG. 4). When the cutting by the stepped reamer 32 and the flushing of the argon gas are repeated a predetermined number of times, the robot hand 15 stops the rotation of the hand portion 15e and holds the reamer cleaning tool 18A while holding the lower portion of the stocker 17 at the lower left. Move up and raise. Then, the ball (not shown) of the spring plunger on the left part of the stocker 17
Is the engagement groove 3 of the holder of the reamer cleaning tool 18A.
3a, projecting inward and engaging with the reamer cleaning tool 1
8A is held at the left portion of the stocker 17 as shown in FIG. The robot hand 15 includes a hand unit 15e
Is opened to release the grip of the reamer cleaning tool 18A, and the hand 15e is lowered. Thus, the first-stage cleaning operation is completed. If the inner surface 3f of the anode tube of FIG. 4 can be sufficiently removed only by the second-stage cleaning operation described below, the first-stage cleaning operation may be performed only on the tip end surface 3e of the anode tube. Good. As described in the prior art, the inner surface 3f of the anode tube cannot be sufficiently removed by the stepped reamer 32 shown in FIG. Therefore, the following second stage cleaning operation is performed. First, the robot hand 15 moves the hand unit 15 e to the lower right part of the stocker 17. Then, the raised hand portion 15e is closed, and the brush cleaning tool 18B is gripped. Thereafter, the robot hand 15 moves the brush cleaning tool 18 in the same manner as the first stage cleaning operation.
B is removed from the stocker 17, moved to below the anode tube 3d, raised while rotating, and the upper part of the brush 30 is inserted into the inside of the anode tube 3d, and the inner surface 3f of the anode tube
(FIG. 4) is polished. After the polishing by the brush 30 for a predetermined time and the flushing of the argon gas are repeated a predetermined number of times, the brush cleaning tool 18B is moved to the stocker 1.
7 to the right. The robot hand 15
The hand 15e is opened to release the grip of the brush cleaning tool 18B, and the process returns to the initial state shown in FIG. Now the second
The stage cleaning operation is completed. Note that the first and second cleaning steps may be performed periodically or every time before the analysis. However, before the analysis of a sample of a different type from the last time or the precise analysis of the outermost layer, the cleaning operation may be performed at any time. May go. As described above, according to the apparatus of the present embodiment, the brush 30 shown in FIG.
Is soft and the abrasive grains 30c are spherical, so that it can be appropriately polished without damaging the inner surface 3f of the anode tube of FIG. 4, and therefore, the inner surface of the anode tube 3f can be sufficiently removed. Moreover, this cleaning operation is performed by the robot hand 1 shown in FIG.
5 makes it easy . Also, in the present invention, the brush according to the inner diameter of the anode tube by preparing a plurality of use select
There, an automatic cleaning unit of the analytical device, since selecting a brush according to the inner diameter of the anode tube to be used in the analysis, can cope with the case where the inner diameter of the anode tube to be used for analysis is changed. As described above, when the cleaning operation is completed, the operator positions the desired portion of the sample 6 to be analyzed so as to face the anode tube 3d, and places the analysis surface 6a of the sample on the support block 2. To make horizontal contact from below (state shown in FIG. 1). When the inner space V in FIG. 4 is evacuated to a rare gas atmosphere (500 to 1300 Pa) of argon by a pressure reducing means (not shown), the analysis surface 6a of the sample is sealed by the atmospheric pressure applied to the back surface 6e.
1 and is pressed against the support block 2 to be in close contact therewith.
In the present embodiment, the support block (support portion) of the glow discharge tube 1 is placed in a state where the analysis surface 6a of the sample is horizontal.
However, the present invention is not limited thereto. For example, the sample may be brought into contact with the support of the glow discharge tube in a state where the analysis surface of the sample is vertical. The power supply means 12 is provided between the anode tube 3d and the sample 6 via the anode block 3 and the support block 2.
When a high voltage of several hundred to several thousand volts is applied, a glow discharge is generated, and cations of argon are generated. This A
The sample 6 is sputtered by the r ions, and the generated light S passes through the window 13a and travels through the entrance slit 24 of FIG. The diffraction grating 26 diffracts light of a predetermined wavelength and makes the light enter a photomultiplier tube 28 through an exit slit 27. The photomultiplier tube 28 measures the intensity of the incident light. That is,
A desired portion of the sample 6 is analyzed. Thereafter, the decompression of the inner space V (FIG. 1) by the decompression means is released, the sample 6 is removed from the support block 2, and the analysis operation is completed. As described above, according to the apparatus of the present embodiment, the stain on the inner surface 3f (FIG. 4) of the anode tube, which causes the background of the analysis, can be sufficiently removed, so that more accurate analysis can be performed. In particular, sufficiently accurate analysis is possible when analyzing a sample 6 of a different type from the previous time or when precisely analyzing the outermost layer of the sample 6 of the same type. As an example, an analysis result of the conventional technique using only the stepped reamer 32 of FIG. 1 for oxygen contained in the same sample 6 (a boron-phosphorus silicate glass film formed on a silicon wafer), and furthermore, FIGS. 5 and 6 show the results of analysis performed by the apparatus of this embodiment that also uses the brush 30. In both figures, the emission intensity corresponding to the amount of oxygen becomes almost 0 when the time has elapsed for about 10 seconds, and the boron-phosphorus silicate glass film to be analyzed disappears at the depth sputtered for about 10 seconds and reaches the silicon wafer. However, by then, the oxygen content should actually be almost uniform. Nevertheless, according to the analysis result of FIG. 5 according to the conventional technique, it takes 5 seconds or more from the start of the analysis until the emission intensity has a certain gentle gradient, and the so-called rise is poor. This is probably because the sputtered oxygen does not contribute to light emission by reacting with the stain on the inner surface 3f of the anode tube in FIG. 4 that cannot be completely removed by the conventional technique. That is, it takes 5 seconds or more, that is, half or more of 10 seconds, which is a substantial analysis time, before the stain on the inner surface 3f of the anode tube completely reacts with the sputtered oxygen, and at least during this time, accurate analysis has been completed. Absent. On the other hand, in the analysis result of FIG. 6 by the apparatus of the present embodiment, the emission intensity has a constant gentle gradient within less than 1 second from the start of the analysis, and the rise is good. This is because the brush 30 (FIG. 2A) can sufficiently remove the dirt on the inner surface 3f of the anode tube in FIG. 4 which cannot be completely removed by the conventional technique. This is considered to contribute to light emission immediately after the start. That is, according to the apparatus of the present embodiment, more accurate analysis can be performed. As described above, according to the present invention,
Since the brush used for cleaning has a soft abrasive surface and spherical abrasive grains, it can be properly polished without damaging the inner surface of the anode tube, and therefore, the dirt on the inner surface of the anode tube can be sufficiently removed and more accurate Analysis.

BRIEF DESCRIPTION OF THE DRAWINGS [Figure 1] Glow discharge emission spectral analysis of an embodiment of the present invention
Is a front view showing the equipment. FIG. 2A is a front view showing a brush provided in the device, and FIG. 2B is a plan view showing the brush. FIG. 3 is a front view showing a spectroscope provided in the apparatus. FIG. 4 is a longitudinal sectional view showing a glow discharge tube provided in the apparatus. FIG. 5 is a diagram showing an example of an analysis result according to a conventional technique. FIG. 6 is a diagram illustrating an example of an analysis result obtained by the apparatus according to the embodiment of the present invention. [Description of Signs] 1 glow discharge tube, 3d anode tube, 3f inner surface of anode tube, 6 sample, 12 feeding means, 13 spectroscope, 15
Automatic cleaning means (robot hand), 30: brush, 30b: flexible branch, 30c: spherical abrasive, V: inner space.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-5156 (JP, A) JP-A-9-329551 (JP, A) JP-A-1-264777 (JP, A) JP-A-7-329 276197 (JP, A) Japanese Utility Model 3-8750 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 21/62-21/74 PATOLIS

Claims (1)

(57) Claims: 1. A glow discharge tube having an anode tube, and a decompression device for evacuating an inner space in which the anode tube is housed.
Glow discharge by applying a voltage between the step and the anode tube and the sample.
Power supply means for generating , and spherical abrasive grains at the tip for polishing the inner surface of the anode tube
A generally cylindrical brush having a number of flexible branches with a brush, and polishing the inner surface of the anode tube using the brush before analysis
Glow discharge light emission component with automatic cleaning means
An optical analyzer, comprising: a plurality of the brushes according to the inner diameter of the anode tube; wherein the automatic cleaning means includes an anode tube used for analysis.
Glow discharge emission spectral component for selecting the brush according to the diameter
Analyzer .