JPH05312738A - Analyzer - Google Patents

Abstract

PURPOSE:To measure the content of a thin film, etc., easily and with a high accuracy by a method wherein a weight measuring means which measures the total weight of a sample is unified with the main part of a measurement apparatus which is composed of an exciting means which generates an X-ray, etc., and applies it to the sample and a detecting means which detects an X-ray, etc., emitted from the sample at that time. CONSTITUTION:An X-ray tube 3 which is placed in a sample chamber 2 and applies an X-ray to a sample 10, an electronic balance 5 which is placed in a sample chamber 2 and measures the total weight of the sample 10 and a detecting means which is placed in a sample measurement chamber 1 and detects the intensity of a fluorescent X-ray emitted from the thin film material surface of the sample are unified to constitute an analyzer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to physical analysis techniques, and in particular to
The present invention relates to a technique that is effective for measuring the weight ratio and the content rate of each of the objects to be measured having different laminated states.

[0002]

2. Description of the Related Art When a solder layer is formed on the surface of a wafer,
For example, a lead (Pb) film is vapor-deposited on the lower layer, and a tin (Sn) film is vapor-deposited on the surface thereof. The content of Pb and Sn may be specified by the customer (for example, determined from the viewpoint of melting point, temperature cycle test, etc.). In this case, is the content within the specified allowable value? You must inspect whether or not.

Conventionally, Pb /
There is a method in which Sn is dissolved with an acid, and this is mounted on a high frequency induction emission analyzer, an atomic analyzer, or the like to perform measurement.

[0004]

According to the study by the present inventor, the technique of dissolving Pb / Sn with an acid and analyzing it with an analyzer requires a pretreatment of dissolution and requires skill in the work. However, there is a problem that it is difficult for workers on site to do. Further, the measurement accuracy of the measuring device is several percent, and it is difficult to measure the content rate with high accuracy.

Therefore, an object of the present invention is to provide an analyzer capable of measuring the content rate of a thin film or the like easily and with high accuracy.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0007]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, excitation means for irradiating the sample with any of X-rays, electron beams and ions, weight measuring means for measuring the total weight of the sample, and X-rays emitted from the thin film material surface of the sample. , And detection means for detecting the intensity of the electron beam or ions.

[0009]

According to the above-mentioned means, the total weight of the sample is added to the main part of the measuring device, which is composed of the exciting means for generating X-rays and irradiating the sample and the detecting means for detecting the X-rays from the sample at this time. By integrating the weight measuring means for measuring, the content rate of the thin film or the like can be easily measured in a short time and with high accuracy.

[0010]

1 is a front sectional view showing an embodiment of an analyzer according to the present invention.

In the spherical sample measuring chamber 1, a detecting means 18 including a detector and a spectroscopic system is installed. This sample measurement room 1
A sample chamber 2 is provided in connection with the X-ray tube 3, and an X-ray tube 3 as an excitation means is installed above the sample chamber 2. Further, a sample loading / unloading lid 4 which is opened when loading / unloading the sample is provided in a part of the upper part of the sample chamber 2. In addition, a plurality of samples 10 (here, 2) are set near the floor of the sample chamber 2.
The electronic balance 5 (weight measuring means) is attached to both ends of the sample table 6, and the sample table 6 is fixed to a support rod 7 that rotates using a motor (not shown) as a drive source. The partition 8 between the sample measuring chamber 1 and the sample chamber 2 is made of a material that transmits X-rays.

Further, the upper portion of the sample measuring chamber 1 is constructed so that it can be opened for the convenience of access of the detector of the detection means 18 and the spectroscopic system (in FIG. 1, the state in which the cover is left uncovered). Is shown). A vacuum pump 9 is connected to the sample measuring chamber 1 to evacuate the interior of the sample measuring chamber 1. Further, the vacuum pump 9 has a solenoid valve 1
1 is provided on the way to evacuate the inside of the sample chamber 2
2 is connected.

A high voltage power supply 13 for generating X-rays is connected to the X-ray tube 3.

FIG. 2 is a block diagram showing the details of the detecting means 18.

The diffraction phenomenon of the crystal lattice is used to separate (split) the characteristic X-rays of various elements emitted from the sample 10 placed on the electronic balance 5. For this purpose, the dispersive crystal 14 is used as a sample. It is arranged on the traveling path of the proper X-ray from 10. As the dispersive crystal 14, LiF (lithium fluoride), ADP (ammonium dihydrogen phosphate), or the like is used. This dispersive crystal 14 is a goniometer (goniometer).
It is attached to the center of rotation so that it can rotate. A collimator 15 is arranged between the dispersive crystal 14 and the sample 10. The collimator 15 is configured by arranging thin plates of stainless steel or the like in parallel at intervals of about 0.1 mm. Further, a detector 16 is arranged on the spectral path of the dispersive crystal 14. As the detector 16, for example, a proportional counter, a scintillation counter or the like is used.

The detection output of the detector 16 and the weighing output of the electronic balance 5 are taken into a computer (for example, a device having the ability of a personal computer) 17 to calculate the weight ratio and the like.

Next, in the embodiment having the above configuration, Pb / S
A method for obtaining the weight ratio of n will be described.

First, the sample loading / unloading lid 4 is opened, the sample 10 is set on each of the electronic balances 5, and then the sample loading / unloading lid 4 is closed. Then, the detector and the spectroscopic system shown in FIG. 2 are set in the sample measuring chamber 1, and then the sample measuring chamber 1 is sealed. Further, the vacuum pump 9 is operated to reduce the pressure inside the sample measuring chamber 1 and the sample chamber 2. Then, the high voltage power source 13 is turned on to excite the X-ray tube 3. As a result, the sample 10 is irradiated with the X-rays from the X-ray tube 3, and fluorescent X-rays are generated from the sample 10.
Reach 4. Here, since the diffraction crystal 14 is rotated by a goniometer and diffraction occurs at an angle that satisfies the Bragg condition, this is input to the detector 16 at a double angle (double the angular velocity) of the analysis crystal. ..

By the way, in order to obtain the Sn content of Pb / Sn, the total weight of Pb / Sn and the weight of Sn may be obtained.

Sn (wt%) = Sn (weight) / (Pb + Sn) (weight) (1) Therefore, in the present invention, {Pb + Sn + material weight (wafer weight)} is obtained by the electronic balance 5 (note that Wafer weight is Sn
And Pb are measured before vapor deposition), Sn (weight) is determined based on the intensity of the fluorescent X-ray, and the Sn content is determined from the equation (1).

That is, the fluorescent X-ray spectrum is obtained by the computer 17 based on each of the intensity of the fluorescent X-ray, the weight measurement value of the electronic balance 5, and the diffraction angle of the dispersive crystal 14, and the change of the intensity with respect to the diffraction angle (waveform The type of sample can be specified from (appearing as a peak). Therefore, by grasping the relationship between the Sn thickness and the X-ray intensity in advance as shown in FIG. 3, the thickness can be known from the value of the X-ray intensity, and the weight can be known from the thickness. By setting the relationship shown in FIG. 3 as a table and referring to the obtained X-ray intensity, it is possible to automatically process the final result.

As described above, according to the above-described embodiment, the fluorescent X-ray measurement and the weight measurement can be performed with one apparatus, and the weight ratio of Pb and Sn can be easily calculated without requiring skill in the measurement. You can ask. Also, automation is possible. In this case, since the measurement accuracy of the electronic balance 5 can be set to about 5 significant digits, the measurement accuracy of the content rate depends only on the accuracy of the excitation means and the detection means, for example, 1%. The following highly accurate measurements are also possible.

When the measurement of one of the samples 10 is completed, the support rod 7 is rotated by a predetermined angle (180 degrees in this embodiment) so that the second sample 10 comes to the X-ray irradiation position. When the measurement of the sample 10 in the sample chamber 2 is completed, the electromagnetic valve 11 is closed to return the sample chamber 2 to normal pressure,
The sample loading / unloading lid 4 is opened, all the samples 10 are taken out, and the next sample 10 is set on the electronic balance 5. Then, after opening the solenoid valve 11, the vacuum pump 9 is operated again, and
By repeating the above-mentioned operations and calculations, each S of the sample 10
Determine the n content.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, in the above embodiment, the objects to be measured are limited to Sn and Pb, but the present invention is not limited to this, and it is possible to measure any substance.

Further, in the above embodiment, the example in which the thin film on the material (wafer) has two layers is shown, but the present invention can be similarly applied to the case where the thin film has two or more layers (however, the irradiation is Range that does not exceed the critical X-ray thickness).

Further, although the excitation source is the X-ray in the above embodiment, the present invention is not limited to this. Ions (secondary ions, reflected ions, etc.) and electrons (reflected ions) emitted upon irradiation of ions, electrons, etc. Qualitative / quantitative analysis is possible by detecting primary electrons, Auger electrons, etc.), intrinsic X-rays, light, etc.

[0028]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

That is, excitation means for irradiating the sample with any of X-rays, electron beams and ions, weight measuring means for measuring the total weight of the sample, and X-rays emitted from the thin film material surface of the sample. Since the detecting means for detecting the intensity of the electron beam or the ion is provided, the content of the thin film formed on the sample can be easily measured in a short time and with high accuracy. Then, it becomes possible to contribute to the improvement of the yield in the subsequent heat treatment process.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of an analyzer according to the present invention.

FIG. 2 is a configuration diagram showing a detection means of the analyzer according to the present invention.

FIG. 3 is a characteristic diagram showing a relationship between Sn thickness and X-ray intensity.

[Explanation of symbols]

 1 sample measuring room 2 sample room 3 X-ray tube 4 sample loading / unloading lid 5 electronic balance 6 sample stand 7 support rod 8 partition 9 vacuum pump 10 sample 11 solenoid valve 12 piping 13 high voltage power supply 14 spectroscopic crystal 15 collimator 16 detector 17 Computer 18 detection means

Claims (4)

[Claims] 1. Exciting means for irradiating a sample with any of X-rays, electron beams and ions, weight measuring means for measuring the total weight of the sample, and X-rays emitted from the thin film material surface of the sample. And a detection means for detecting the intensity of an electron beam or an ion. 2. The analyzer according to claim 1, wherein the weight measuring unit is an electronic balance. 3. A weight for one of the thin film materials is obtained based on the detected intensity, and this weight value is divided by the weight of all thin films to obtain a weight ratio of one of the thin film materials to another thin film material. The analyzer according to claim 1, wherein 4. The analyzer according to claim 3, wherein the thin film is a lead thin film and a tin thin film.