JPH07110299A - Glow discharge emission spectral analyzer - Google Patents

Abstract

PURPOSE:To provide a glow discharge emission spectral analyzer whose discharge efficiency does not decrease even if a high-frequency power is supplied. CONSTITUTION:An electrically insulated support block 7 consisting of polyimide resin is allowed to contact one end face of an anode block 3 and a sample 5 consisting of a cathode block 2 with cooling means 2a and 2b is pressed to one end face of the support block 7. A voltage is applied between the sample 5 and the anode block 3 via the cathode block 2 and a feeder means 10 for performing glow discharge is provided. Since the support block 7 which has an electrical insulation property and can be formed thickly is included between the anode block 3 and the cathode block 2, the distance between anodes increases, the capacitance can be suppressed to a small level, and a high discharge efficiency can be maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glow discharge optical emission spectrometer for analyzing generated light while sputtering a sample.

[0002]

2. Description of the Related Art When a DC high voltage is applied between two electrodes in an argon (Ar) atmosphere having a gas pressure of about 4 to 10 Torr, glow discharge occurs and Ar ions are generated. The generated Ar ions are accelerated by a high electric field, collide with the cathode surface, and knock out the substances present therein. This phenomenon is called sputtering. Sputtered particles (atoms, molecules, ions) are excited in plasma and emit light of a wavelength peculiar to the element when returning to the ground state. An analysis method of spectrally analyzing the emitted light with a spectroscope to identify an element is called a glow discharge emission spectral analysis method.

A hollow anode type grim glow discharge tube 1 as shown in FIG. 4 is generally used as a glow discharge tube in an analyzer that embodies the glow discharge emission spectral analysis method described above. In this grim glow discharge tube 1, a cathode block 2 and an anode block 3 are joined via a Teflon washer 4 which is an insulator. Anode block 3
Has an argon gas supply hole 3a and first and second vacuum exhaust holes 3b and 3c, and the inside V of the tube is a rare gas atmosphere of argon (4 to 10 Torr). A hollow anode tube 3d is formed integrally with the anode block 3, and the anode tube 3d penetrates the Teflon washer 4 to form a sample 5
Is close to the surface 5a. This sample 5 is an O-ring 6
It is pressed against the cathode block 2 in an airtight manner via.

The Grim glow discharge tube 1 applies a high DC voltage between the anode block 3 and the cathode block 2 to generate glow discharge, and at the same time applies a negative voltage to the sample 5 through the cathode block 2 which is generally made of copper. The sample 5 is applied to cause argon cations generated by the generation of glow discharge to collide with the surface of the sample 5 to sputter the sample 5. In addition, the cooling liquid K is introduced into the jacket 2b from the cooling liquid introduction passage 2a of the cathode block 2 and the cooling liquid discharge passage 2
Feeding to c, cathode block 2 and cathode block 2
The sample 5 and the hollow anode tube 3d are cooled via the.

[0005]

Conventionally, a high DC voltage was applied between the anode block 3 and the cathode block 2 to analyze the conductive sample 5, but in recent years, high frequency power has been utilized. A method for analyzing insulating samples is being established. However, when high frequency power is supplied between the anode block 3 and the cathode block 2 of the glow discharge tube 1 having the above structure, the following problems occur.

The electrostatic capacitance C between the anode block 3 and the cathode block 2 is C = where S is the area of the opposing electrode portions facing each other, d is the distance between the electrodes, and ε is the dielectric constant between the electrodes. It is calculated by the formula εS / d. However, in the glow discharge tube 1, the facing area between the anode block 3 and the cathode block 2, that is, the area S of the facing electrode is large, and
Since the Teflon washer 4 is thin, the distance d between the electrodes is small. Therefore, as is apparent from the above formula, the electrostatic capacitance C becomes large, and the anode block 3 and the cathode block 2 sandwiching the Teflon washer 4 function as a large-capacity capacitor, and the Teflon washer 4 for high-frequency power is used. The electrical insulation property of is significantly reduced, and a large current flows between the anode block 3 and the cathode block 2. Therefore, there is a problem that the electric power that contributes to the glow discharge decreases and the discharge efficiency decreases.

Therefore, an object of the present invention is to provide a glow discharge emission spectroscopic analyzer in which the discharge efficiency does not decrease even when high frequency power is supplied.

[0008]

In order to achieve the above object, a glow discharge emission spectroscopic analyzer according to the present invention comprises an anode block and an electrical insulating property made of a polyimide resin in contact with one end surface of the anode block. Support block of
A sample is in contact with one end surface of the support block, a cathode block is in contact with the sample, a cooling means for cooling the cathode block, and a voltage is applied between the anode block and the sample to generate glow discharge. And a power feeding means.

[0009]

[Operation] When a high frequency voltage is supplied between the sample and the anode block through the cathode block to perform glow discharge,
The support block joined to the anode block is made of electrically insulating polyimide resin and does not function as a cathode.
Since the support block made of resin and having a large thickness is interposed between the anode block and the cathode block, the distance between the electrodes can be increased. Therefore, the electrostatic capacity does not increase, and high discharge efficiency can be maintained.
In addition, since the polyimide resin, which is the material of the support block, has high heat resistance, it is not thermally damaged due to temperature rise due to glow discharge. On the other hand, the cathode block is
It has three functions: power supply to the sample, holding and pressing the sample, and cooling the sample.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a glow discharge tube 17 in an embodiment of the glow discharge emission spectral analyzer of the present invention. In the figure, the same or corresponding parts as in FIG. 4 are designated by the same reference numerals.

An electrically insulating support block 7 made of polyimide resin is provided at the cathode portion of the existing glow discharge tube 1 where the cathode block 2 was provided. The copper cathode block 2 is pressed against the back surface of the sample 5 by the pressing mechanism 9 via the insulator 8. This cathode block 2 is provided with a cooling means for introducing the cooling K from the cooling liquid introducing passage 2a to the jacket 2b and feeding it to the cooling liquid discharging passage 2c, as in the existing one. A high frequency power source (power feeding means) 10 is connected to the anode block 3 and the cathode block 2.

FIG. 2 shows an overall schematic structure of the glow discharge emission spectral analyzer of the present invention, and the operation will be described with reference to FIG. 1 and FIG. When a high-frequency voltage of several hundred to several thousand volts is applied from the high-frequency power source 10 between the sample 5 and the anode block 3 through the cathode block 2, glow discharge is caused and argon cations are generated. The generated Ar ions collide with the sample 5, which is the cathode, and knock out atoms from the surface 5 a of the sample 5. The atoms that are knocked out and peeled off are excited by Ar ions or electrons, and emit light L unique to the element when returning to the ground state again.

The light L thus emitted passes through the window plate 11 of the glow discharge tube 17, passes through the entrance slit 12, and
It goes to the diffraction grating 14 of the spectroscope 13. The light L that has entered the spectroscope 13 is diffracted into light having a predetermined wavelength by the diffraction grating 14, is separated into each wavelength, and enters the photomultiplier tube 15 through the exit slit 16, and the intensity thereof is measured. The surface 5a of the sample 5 is sputtered, and its thickness gradually decreases with time. The measured intensity is measured with the lapse of sputtering time to obtain a spectrum of the analysis element, and from this spectrum, the analysis of the element along the thickness direction of the sample is performed by a known method.

In this way, between the anode block 3 and the cathode block 2, the support block 7 which is made of resin and can be formed to have a remarkably large thickness as compared with the existing Teflon washer 4 is interposed as shown in FIG. Therefore, the distance between the electrodes does not increase and the electrostatic capacitance does not increase, so that high discharge efficiency can be maintained.

Further, since the polyimide resin, which is the material of the support block 7, has a usable temperature of about 300 ° and has the highest heat resistance among the resins, it is thermally damaged due to temperature rise due to glow discharge. There is no. Moreover, since the polyimide-based resin has excellent machinability, it has an advantage that mechanical accuracy can be easily obtained. Although ceramics are generally used as the insulating material, this ceramic has a defect that the dielectric constant is high and cracks easily occur. Therefore, in the present invention, polyimide is used as the material of the support block 7. A system resin is used. Needless to say, in the glow discharge tube 17 of FIG. 1, the high frequency power supply 10 can be driven without any problem even if the high frequency power supply 10 is replaced with a direct current power supply.

Further, since the cathode block 2 in the glow discharge tube 17 has three functions of supplying power to the sample 5, holding the sample 5 by pressing, and cooling the sample 4, the number of parts is increased. Is suppressed as much as possible. The cathode block 2 is formed of copper as a material, and therefore has excellent electrical conductivity and thermal conductivity.

Next, the support block 7 is formed to have a relatively large diameter as shown in FIG. 1, and its purpose will be described with reference to FIG. Since the sputtered powder scraped by the sample 5 being sputtered adheres to the tip end surface 31 and the inner peripheral surface 32 of the hollow anode tube 3d, the spatter deposit is automatically attached to the main body 18 with the rotary cutting blade 19. It is removed by the cleaning device 20. However,
If the plane cutting portion 19a of the automatic cleaning device 20 is brought into direct contact with the tip surface 31 of the hollow anode tube 3d, the tip surface 31 will be scraped. In addition, the automatic cleaning device 2
When the main body 18 of 0 is brought into contact with the sample holding surface 7a of the support block 7 against which the sample 5 is pressed, the sample holding surface 7a may be damaged.

Therefore, the support block 7 is formed to have a large diameter, and the contact surface 7b is provided radially outward of the sample holding surface 7a.
On the other hand, the distance D1 between the plane cutting portion 19a of the automatic cleaning device 20 and the front surface 18a of the main body is set to be equal to the distance D between the sample holding surface 7a of the support block 7 and the hollow anode tube 3d. In this state, when the sputter deposit is removed by the automatic cleaning device 20, the front surface 18a of the main body comes into contact with the contact surface 7b on the outer side of the support block 7 and the flat cutting portion 19a is hollow, as shown by a phantom line in FIG. Anode tube 3
It is positioned so that it does not go inward from the tip surface 31 of d, the cylindrical cutting portion 18b is inserted into the hollow portion of the hollow anode tube 3d, and the tip of the hollow anode tube 3d is rotated by the rotation of the rotary cutting blade 19. Sputter deposits on the surface 31 and the inner peripheral surface 32 are removed.

[0019]

As described above, according to the glow discharge emission spectroscopy analyzer of the present invention, the support block, which is made of resin and can be formed with a large thickness, is interposed between the anode block and the cathode block. Therefore, the distance between the electrodes becomes large. Therefore, the capacitance between the anode block and the cathode block does not increase, and high discharge efficiency can be maintained. In addition, since the polyimide resin, which is the material of the support block, has high heat resistance, it is not thermally damaged due to temperature rise due to glow discharge. Further, the cathode block can have the three functions of supplying power to the sample, holding the sample by pressing, and cooling the sample.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a grim glow discharge tube of a glow discharge emission spectral analyzer according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of the same glow discharge emission spectral analyzer.

FIG. 3 is a vertical cross-sectional view showing a state where sputter deposits are removed in the example.

FIG. 4 is a cross-sectional view showing a Grim glow discharge tube in a conventional device.

[Explanation of symbols]

2 ... Cathode block, 2a ... Coolant introducing passage (cooling means),
2b ... Jacket (cooling means), 3 ... Anode block, 5
... sample, 7 ... support block, 10 ... high frequency power source (power supply means).

Claims (1)

[Claims] 1. An anode block, an electrically insulating support block made of a polyimide resin that contacts one end surface of this anode block, a sample that contacts one end surface of this support block, and a cathode block that contacts this sample. A glow discharge emission spectroscopy analyzer comprising: a cooling unit for cooling the cathode block; and a power supply unit for applying a voltage between the anode block and the sample to generate glow discharge.