JPH0414742B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a novel method for quantifying S, and an S monitor capable of highly sensitive detection and quantification on the spot using the method. The present invention relates to semiconductor manufacturing products, manufacturing equipment, waste processing equipment, etc. that use S, such as Zns, Cds,
Growth equipment for compound semiconductors such as ZnSxSe _1-x (CVD furnace, LPE furnace, etc.), high pressure HB furnace, annealing furnace, S pressure annealing furnace, MBE equipment, MOCVD
It can be used as a high-sensitivity monitor for detecting and quantifying S in equipment, or can be used in melting furnaces for S-containing alloys, ceramics, glasses, etc. (Prior art) Conventionally, when detecting S, there is almost no known method for detecting and quantifying gaseous S on the spot in a non-destructive manner without disturbing the system. is the main thing. Gas chromatography can be considered as a non-destructive detection/quantification method for gaseous substances.
It is unsuitable because it has the inherent problem that it adheres to the wall of the introduction tube before the sample is introduced into the measurement system, making accurate quantification impossible, and that it disturbs the system because it requires sampling from within the system. , has not been put into practice. In addition, although atomic absorption spectrometry can accurately measure samples in the atomic state, it requires the sample to be heated to a high temperature of 2000°C or higher, and detection and quantification at temperatures below the atomization temperature is theoretically impossible. , there are no hollow cathode lamps available. (Means to be Solved by the Invention) The present invention has been made in view of the above-mentioned current situation, and is non-destructive, does not leak out the system, and is capable of producing gaseous Sulfur on the spot.
The purpose of the present invention is to provide a method capable of detecting and quantifying with high sensitivity, and a highly sensitive monitor using the method. (Means for solving the problem) That is, the present invention provides gaseous S with a wavelength of 263 nm,
265.5nm, 268nm, 270.5nm, 273nm, 276nm,
At least one of the group peaks having peaks at 279nm and 282nm (hereinafter referred to as peaks) and wavelengths of 264.5nm, 267nm, 269.5nm, 272nm,
At least one spectral line of the group peak having valleys (hereinafter referred to as valley peaks) at 275 nm, 278 nm, and 281 nm is incident, and the absorption of the incident spectral line by the gaseous S is measured, and each light intensity is measured. Method for detecting and quantifying S from the peak height of
268nm, 270.5nm, 273nm, 276nm, 279nm,
At least one of the group peaks having a peak of 282 nm and a wavelength of 264.5 nm, 267 nm,
At least one spectral line light-emitting part of the first group of peaks having valley peaks of 269.5 nm, 272 nm, 275 nm, 278 nm, and 281 nm, and the other window contains light of the spectral line that has passed through the gaseous S in the heater-equipped container. This is an S monitor that is connected to a light receiving and photometric unit that detects and quantifies S based on the height of the peak intensity. The present invention will be explained in detail below. The present inventors have discovered that gaseous S (in gaseous form S ₂ , S ₄ ,
It is thought that it will be S ₆ , S _8, etc., but it has not been identified. ) As a result of detailed research on the absorption spectra of
As shown in Figure 1, the wavelengths are 263nm, 265.5nm,
268nm, 270.5nm, 273nm, 276nm, 279nm and
The absorption peak of the first group is at 282nm, and the wavelength
264.5nm, 267nm, 269.5nm, 272nm, 275nm,
It was discovered that there is a group of absorbance trough peaks at 278 nm and 281 nm. The peaks and valleys of the first and second groups are S at a temperature of about 300°C.
By using the above-mentioned absorption peaks caused by the absorption of gaseous S, it is possible to detect and quantify gaseous S with high sensitivity even on the spot. That is. The reason why the valley peak can be used for this detection and quantification is as follows. In Figure 6, m
indicates the transmission of background light, and if there is no absorption etc., m is measured. For it,
If light is absorbed, the amount of light is absorbed by the absorption amount a, and the value of i is measured. The absorption of light seems to be related to the structure of the S molecule, and it is presumed that the absorption of light is due to energy being absorbed by vibrations such as bonding between S and S, so the amount of light transmitted in the background is If a calibration curve has been created in advance, the light absorption amount Ia for Im can be adjusted to S by measuring Ii, that is, by measuring the peak of the valley with respect to Im. Can be quantified. In fact, at least one of the above group peaks
Since at least one spectral line of the first and second group peaks is simultaneously incident, measured separately using a spectrometer in the light emitting part, and then averaged, separation from other substances is easier than when using a single spectral line. It becomes more reliable and the precision of S quantification improves. As shown in FIG. 2, the present invention involves attaching a window 2 to a furnace, a cell with a heater, or a cylindrical portion 1, causing a light emitting portion 3 to emit spectrum lines of the above-mentioned group peaks and group peaks, and transmitting this light to the window 2. incident from
By measuring the peak height of light intensity in the light receiving section 4, S in the furnace or cell is detected and quantified. The detection and quantification of S is determined from the fact that the peak absorption of the above group peak and group peak is proportional to the S concentration. The relationship between peak absorption and S concentration is expressed by the equations (1) and (2) above: D=log1/T (%) (1) D∝C (2). Here, T is the absorbance at the peak (%), and C is the concentration of S. As the spectral emission source for the above-mentioned 1st and group peaks, a hollow cathode lamp can be used, which is provided with a filter centered on the 1st and group peaks, respectively. Further, the filter can also be provided in the light receiving section. Furthermore, the detection results can be processed by a computer and the results can be displayed. If you do this,
Since it is possible to quantitatively detect S in almost real time, it is possible to realize a highly sensitive S monitor that can detect and quantify S on the spot and control the amount of S input, S pressure, etc. (Example) FIG. 3a is a schematic diagram of an apparatus used in an example of the present invention, in which 1 is a cell, 2 is a window, 3 is a light emitting part, and 4 is a schematic diagram of a device used in an example of the present invention.
5 represents a light receiving section, and 5 represents a heating means. Note that FIG. 3b is a graph showing the temperature distribution of this device. FIG. 4 shows the spectrum obtained when S was placed in the cell 1 and the temperature inside the cell 1 was kept constant at 298° C. by the heating means 5. Group peaks: wavelengths 263nm, 265.5nm, 268nm, 270.5nm, 273nm,
Absorption spectrum with maximum peaks at 276nm, 279nm and 282nm and group peak, i.e. wavelength
264.5nm, 267nm, 269.5nm, 272nm, 275nm,
An absorption spectrum with valley peaks at 278 nm and 281 nm was clearly measured. On the other hand, it was confirmed through detailed experiments that there is generally a relationship shown in FIG. 5 between the amount of S added and the absorbance. Here, if the light intensity detected when gaseous S is present is I, and the light intensity when gaseous S is not present is Io, the absorbance T (%) is given by the following equation (3). T=I/Io×100 (3) Therefore, S can be quantified from the absorbance using equations (1) and (2) above. Note that point A represents the saturation point at temperature t, and is defined by vapor pressure = (logPt (mmHg) = 6750/t + 11.32). Since the relationship shown in FIG. 5 holds true for the absorption spectra of the peaks and valleys of each group, the amount of S can be determined by measuring any of the peaks. Detection is possible down to the order of 0.01ppm. However, according to the present invention, by simultaneously detecting these by using a combination of spectral lines of at least one of the above-mentioned peaks and troughs, and by simultaneously quantifying and averaging from the height of each peak, the S detection and Quantitative accuracy was further improved. That is, in this case, the following evaluation means (a) to (c) are used instead of the above equations (1) and (3). In addition, is the respective average value, n=
1, 2...8 are for the above eight types of peaks,
represents each measurement. (a) D=log1/T(%), (%)= _1i=o 〓 ⁿⁱ⁼¹ I _i /Io _i ×100 n=1, 2,...8 (b) = _1i=o 〓 ⁿⁱ⁼¹ log1 /T _i (%), T _i (%) = I _i /Io _i ×100 n = 1, 2,...8 (c) D = log1/To (%),

[Formula] n=1, 2,...8 Such evaluation is easy and quick using an arithmetic device such as a computer, and since the amount of S can be displayed in real time, the system can be controlled. (Effects of the invention) The effects of the invention are as follows. 1. By utilizing the spectrum of the above-mentioned first group peak (peak) and second group peak (trough) due to the absorption of gaseous S, it has become possible to detect and quantify gaseous S with high sensitivity on the spot. 2. In order to perform simultaneous quantification from the peak height of the spectra of the above-mentioned group peak and group peak,
Clear separation from other substances improves detection accuracy.
Furthermore, the accuracy of S quantitative determination is greatly improved. 3. The high-sensitivity S monitor of the present invention is capable of on-the-spot detection and quantification of the amount of S, and when combined with a calculation device such as a computer, the amount of S can be detected and quantified in real time from the absorbance of each spectrum, and the amount of S can be detected and quantified on the spot. The S input amount, S pressure, etc. can be controlled on the spot based on the output signal of the device.

[Brief explanation of drawings]

FIG. 1 shows the absorption spectrum of gaseous S. FIG. 2 is a schematic diagram showing the outline of the method and monitor of the present invention. FIG. 3a is a schematic diagram of the apparatus used in the embodiment of the present invention, and FIG. 3b is a graph showing the temperature distribution in the apparatus of FIG. 3a. FIG. 4 is a graph showing the relationship between wavelength and absorbance obtained in an example of the present invention, and FIG. 5 is a graph showing the relationship between S amount and absorbance. FIG. 6 is a schematic diagram of an absorption spectrum to show why the valley peak can be used for detecting and quantifying S.

Claims (1)

[Claims] 1 Gaseous S has wavelengths of 263 nm, 265.5 nm,
268nm, 270.5nm, 273nm, 276nm, 279nm,
At least one of the group peaks having a peak of 282 nm and a wavelength of 264.5 nm, 267 nm,
At least one spectral line of the first group peaks having valley peaks of 269.5 nm, 272 nm, 275 nm, 278 nm, and 281 nm is incident, absorption of the incident spectral line by the gaseous S is measured, and the absorption of the incident spectral line by the gaseous S is measured. A method for detecting and quantifying S based on the peak height of light intensity. 2. A window is provided in the direction of light propagation of the furnace or container with a heater, and one window has wavelengths of 263 nm, 265.5 nm,
268nm, 270.5nm, 273nm, 276nm, 279nm,
At least one of the group peaks having a peak of 282 nm and a wavelength of 264.5 nm, 267 nm,
At least one spectral line light-emitting part of the first group of peaks having valley peaks of 269.5 nm, 272 nm, 275 nm, 278 nm, and 281 nm, and the other window contains light of the spectral line that has passed through the gaseous S in the heater-equipped container. The S monitor consists of a light receiving and photometering unit that detects and quantifies S based on the intensity peak height. 3 Detect and quantify S from the peak height of light intensity,
The S monitor according to claim 2, which controls S input amount control and S pressure control in real time. 4. The S monitor according to claim 2, wherein the light emitting section comprises a hollow cathode lamp. 5. The S monitor according to claim 2, wherein the light-emitting section or the light-receiving section has a filter centered on a group peak and a filter centered on the group peak.