JPH09306959A - Semiconductor thin film impurity concentrator and analysis thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To concentrate impurity in a semiconductor thin film without dissolving this sample of semiconductor thin film, and analyze it quickly and easily at high sensitivity. SOLUTION: A concentrator comprises a DC voltage feed means 1 for applying a first and a second different potentials to a first and a second terminals 13 and 17, a closed vessel 3 for shielding a semiconductor thin film sample S from outside, a first electrode 5 which is electrically connected to the first terminal 13 and holds one surface of the sample S in the vessel 3 and a second electrode 7 which is disposed near or on the other surface of the sample S in the vessel 3 and has a sharp edge part near the other surface of the sample S.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impurity concentrating device for a semiconductor thin film and an impurity analyzing method therefor, and more particularly, to an impurity concentrating device for a semiconductor thin film for preparing a sample for analysis of ultratrace impurities in a semiconductor thin film, and The present invention relates to a method for analyzing impurities.

[0002]

_2. Description of the Related Art A semiconductor thin film such as a SiO ₂ film or a Si ₃ N ₄ film is used as a dopant partial diffusion mask or a protective film for a metal vapor deposition film in a silicon semiconductor device. If impurities such as Fe are present,
Even if the amount is extremely small, the electrical characteristics of the device are greatly affected. Therefore, in order to improve the performance of the VLSI element and the like, it is necessary to keep the content of these impurities as low as possible, but in order to achieve this purpose,
It is necessary to accurately measure the concentration of impurities in the semiconductor thin film. As a means for measuring impurities in such a thin film, a thin film sample is dissolved in an acid solution or an acid vapor, impurities are separated and concentrated, and then wet chemical analysis means for measuring by a filmless atomic absorption spectrometry or inductively coupled plasma mass spectrometry etc. Is generally known.

However, in the wet chemical analysis means, a large amount of sample is required, and since the sample is dissolved and the operation of separating and concentrating the impurities is complicated, it requires skill to acquire the analytical operation technique. There was a problem that analysis took time. Furthermore, in order to use an acid solution or acid vapor,
From the viewpoint of environment and health and safety, there was also a problem that a draft for acid, exhaust gas treatment equipment and acid treatment equipment had to be installed, so SIMS (Secondary Ion Mass Spec
trometry), TRXRF (Total Reflection X-ray Fluo
rescence Spectrometry), AES (Auger Electron Spec)
trometry), PIXE (Particle Induced X-ray Emissi
Physical analysis means such as on spectroscopy are commonly used. Since this physical analysis means can usually be directly measured without a chemical treatment operation, it is excellent in quickness. It is also excellent in terms of the amount of analysis sample and the resolution in the depth direction.

Here, in the above-mentioned physical analysis means, S
Except for IMS, it has an analytical sensitivity of about 10 ppm to 10000 ppm and is not suitable for the detection of ultratrace impurity components.
Moreover, although the ppb level can be detected by SIMS, it is difficult to analyze impurities below ppb. Therefore, in order to improve the performance of the VLSI element or the like, it is essential to develop a method for detecting these ultra-trace amount impurity components with the highest possible sensitivity.

Therefore, in order to increase the sensitivity of impurity analysis, conventionally, a thin film sample is dissolved with an acid solution or acid vapor,
After separating and concentrating impurities by solvent extraction separation method or ion exchange separation method, etc., it is dried by heating and measured by physical analysis means, that is, the measurement sensitivity is improved by concentrating impurities by chemical treatment operation etc. A so-called combined means for measuring by a physical analysis means has been used.

[0006]

However, in the method of concentrating impurities by a chemical treatment operation to improve the measurement sensitivity, as described in the above wet chemical analysis means, the sample is dissolved or the impurities are separated and concentrated. Since it is complicated, there is a problem that it requires skill to acquire analysis operation technique and analysis takes time. Further, since the acid solution or the acid vapor is used, from the viewpoint of environment and safety and hygiene, it is necessary to install a dedicated draft for the acid, an exhaust gas treatment equipment and an acid treatment equipment.

The present invention has been made in order to solve such a conventional technique, and its purpose is to concentrate impurities in a semiconductor thin film without performing a chemical treatment operation such as dissolution of a sample. However, it is another object of the present invention to provide a semiconductor thin film impurity concentrating device and an impurity analyzing method capable of performing a quick, simple and highly sensitive analysis.

[0008]

In order to achieve the above object, the inventors of the present invention have conducted earnest studies on a semiconductor thin film, and as a result, when a potential difference is generated in the semiconductor thin film, impurities are epoch-making. It was found that the impurities were concentrated, and the inventors of the present invention invented the semiconductor thin film impurity concentration device and the impurity analysis method thereof.

The impurity concentrating device for a semiconductor thin film according to the present invention is a device for concentrating impurities quickly, simply and at high concentration without dissolving the semiconductor thin film, which is characterized by a potential difference in the semiconductor thin film. The semiconductor thin film is provided with an electrode for concentrating the ionic impurities in the semiconductor thin film to a part of the semiconductor thin film due to a potential difference, and a closed container for blocking the semiconductor thin film from the outside.

Further, a direct current voltage applying means for applying a first potential to the first electrode terminal and a second potential different from the first potential to the second electrode terminal, and the semiconductor thin film. A closed container for blocking the sample from the outside; a first electrode electrically connected to the first electrode terminal for holding the semiconductor thin film sample in the closed container from one surface;
A second electrode which is electrically connected to the electrode terminal of the semiconductor thin film sample and is provided in the vicinity of or on the other surface of the semiconductor thin film sample in the closed container, and a voltage is applied to the first and second electrodes. May be applied to collect the impurities in the semiconductor thin film in the vicinity of the second electrode to concentrate the impurities.

Here, the material of the first electrode and the second electrode is a conductive material such as platinum, gold, palladium, silver, tantalum, copper or the like, which directly or indirectly concentrates the ionic impurities for the purpose of analysis. Any material may be used as long as it does not interfere, and platinum, gold and tantalum are preferable. Further, in the above electrode, impurities for the purpose of analysis from the electrode to the thin film sample,
Also, any material may be used as long as it can apply an arbitrary voltage without moving from the thin film sample to the electrode.

The first electrode holds a part of the semiconductor thin film sample, and a high DC voltage is applied to the semiconductor sample through the above two electrodes to locally concentrate impurities in the semiconductor thin film near the surface. It is provided in the closed container in such a positional relationship as to obtain it. Further, it may be one that holds only one thin film sample (for example, a sample wafer with a thin film), or one that holds a plurality of thin film samples. Here, “holding” includes the concept of fixing, but also includes the operation of simply putting. In order to hold a plurality of thin film samples and simultaneously apply a high DC voltage to them, it is preferable to provide a partition in order to prevent the influence of other samples by separating each sample. Correspondingly, a pair of electrodes is preferably provided for each of the plurality of thin film samples. Moreover, it is preferable that the first and second electrodes are detachable. This is for facilitating the positioning of the semiconductor sample and facilitating the electrode exchange at the time of contamination.

Next, the shape of the second electrode is preferably such that the tip portion thereof is sharpened. This is because a higher electric field is applied to a specific portion of the semiconductor thin film to increase the impurity concentration of the specific portion. Further, the second electrode may or may not be in contact with the semiconductor thin film sample. However, since impurities for the purpose of analysis may adhere to the second electrode, it is preferable to have a positional relationship that keeps an arbitrary distance from the semiconductor thin film sample. Further, the second electrode may be provided with a moving means that moves up and down, back and forth, and left and right to accurately concentrate a predetermined portion of the semiconductor thin film sample.

Next, the DC voltage applying means may be any one that can apply a predetermined DC voltage by converting the AC voltage into a DC voltage or the like in order to locally concentrate the ionic impurities in the semiconductor thin film. May be In order to concentrate the ionic impurities to a high concentration, it is desirable that the DC voltage be as high as possible. However, if the voltage is too high, a strong discharge occurs between the electrode and the semiconductor thin film sample, the ionic impurities in the semiconductor thin film sample evaporate, and the secondary contamination due to the evaporation of impurities from the electrode occurs. The accuracy and sensitivity of the impurity analysis of is significantly reduced. Practically, the DC voltage is preferably 20 to 1000V. Further, the DC voltage applying means has a function of reversing the magnitude of the first potential and the second potential in order to separately concentrate the ionic impurities of the cation and the anion present in the semiconductor thin film sample. Is preferred.

Next, the closed container is for reducing secondary pollution from the environment and for maintaining high concentration of organic vapor and the like. Further, the heating means heats the semiconductor thin film sample to raise the sample temperature in order to accelerate the concentration of ionic impurities in the semiconductor thin film by the DC voltage. In addition, the organic substance solution storage container is heated to raise the temperature of the organic substance solution to form a predetermined film. Therefore, those which can be heated separately are preferable. Here, the heating means may be of any type such as electric resistance heating, infrared heating, laser heating, etc., but electric resistance heating is preferable in terms of heating rate and efficiency. Further, from the viewpoints of cooling efficiency after the concentration operation, heat resistance of the apparatus, etc., it is preferable to heat only the portion to which a voltage is applied. Therefore, heating using light is preferable in that heating control and local heating can be performed accurately and easily. Here, heating with light includes heating with infrared rays, visible light, laser light, microwaves, and the like. Further, it is preferable that these heating means are arranged outside the closed container from the viewpoint of preventing contamination.

From the viewpoint of increasing the concentration rate of ionic impurities, it is desirable that the heating temperature be set as high as possible. However, if the temperature is too high, impurities from the material of the concentrator may be mixed. Therefore, the heating temperature of the semiconductor thin film sample is 300 ° C. or less, particularly 50 to 20 ° C.
The range of 0 ° C is preferred. In addition, in order to fix the concentration state of impurities in the thin film by cooling the semiconductor thin film after heating,
A gas introducing / exhausting means may be provided on the side surface of the closed container.

The materials of the members constituting the device of the present invention include:
It may be anything as long as it does not directly or indirectly interfere with the accurate measurement of impurities in the semiconductor thin film sample. Further, it is preferable that the closed container is provided with a semiconductor thin film sample monitoring means at least a part of which is made of a transparent material so that the DC high voltage application state of the semiconductor thin film sample can be monitored. With such a configuration, the high voltage application process can be stopped according to the high voltage application state, and thus the time required for the high voltage application process can be shortened. Furthermore, since it is not necessary to open the closed container during the high voltage application process to check the high voltage application status, it is possible to prevent impurities from entering from the atmosphere. Since an extremely minute amount of analysis is performed, it is preferable to avoid such contamination of impurities as much as possible, and the effect is great. The transparent material is preferably a heat-resistant and acid-resistant material, for example, quartz or sapphire, a copolymer of ethylene tetrafluoride and ethylene hexafluoride, a copolymer of ethylene tetrafluoride and ethylene, Polyethylene, acrylic,
Polycarbonate, polystyrene, acrylonitrile styrene resin and the like are preferable. A plate material laminated with a transparent resin such as an acrylic resin or a polycarbonate resin with a hydrofluoric acid resistant film may be used.

Here, it is preferable to previously form a predetermined film on the other surface of the semiconductor thin film sample. Here, the film includes an organic film, a carbon film, or a silicon carbide film in addition to the silicon film. By preliminarily forming these films, it is possible to suppress the secondary contamination of the semiconductor thin film sample from the environment and also to suppress the evaporation loss of the target impurities in the thin film. Further, it is desirable that these thin films are set as thick as possible from the viewpoint of suppressing secondary pollution. However, if it is too thick, it takes a long time to analyze, so the film thickness is 3000 Å or less, particularly 100 to 2000 Å for a silicon film, and 2000 Å or less, especially 20 to 1000 Å for an organic film. Is preferred.

The types of organic film include polyimide resin, epoxy resin, polycarbonate, polyethylene,
Polypropylene, polystyrene, naphthalene, organic film such as camphor, or carbon film or silicon carbide film, as long as it does not interfere with the concentration of ionic impurities for analysis directly or indirectly, any may be used, Preferred are polyethylene, polypropylene, polystyrene, naphthalene, camphor, and carbon film. The thin film may be formed by any method such as a coating and drying method or a vapor deposition method, but the vapor deposition method is preferable from the viewpoint of suppressing secondary contamination.

Further, instead of preliminarily forming the above-mentioned membrane before the concentration, a membrane forming means for forming a predetermined membrane may be provided in the closed container. With such a configuration, desorption and the like of the semiconductor thin film sample is unnecessary, and efficient concentration is possible.

In order to clearly specify the analysis range of the semiconductor thin film sample surface, that is, the impurity concentration range, a laser beam having an energy intensity capable of starting the evaporation and vaporization of the semiconductor thin film is irradiated in advance to the periphery of a predetermined position on the semiconductor thin film surface for marking. Preferably.

Next, the method for analyzing impurities in a semiconductor thin film according to the present invention is a method for analyzing impurities quickly, simply and with high sensitivity after concentrating impurities without dissolving the semiconductor thin film. By applying a voltage to the semiconductor thin film sample, the impurities are locally collected and concentrated, and the concentrated semiconductor thin film sample is analyzed for impurities.

Here, in the impurity analysis of the semiconductor thin film sample, secondary ion mass spectrometry, total reflection X-ray fluorescence analysis, P
It is preferable to measure by the IXE method or the AES method.

Next, the gist of the semiconductor thin film impurity concentrating apparatus and its analyzing method according to the present invention will be described. The ionic impurities of the semiconductor thin film are mainly sodium, potassium, magnesium, calcium, fluorine, chlorine, etc., and they are usually present almost uniformly throughout. When a DC voltage is applied to this semiconductor thin film to generate a potential difference, such ionic impurities move due to electrostatic attraction or repulsion, so that they can be concentrated. For example, when the cation impurity sodium uniformly distributed as shown by the line A in the graph of FIG. 2 is applied with a direct current voltage to the semiconductor thin film to generate a potential difference, the surface of the surface applied with a negative potential, that is, a low potential After a certain period of time, the concentration of the cation impurity sodium increases as the distance from the surface on the negative voltage side decreases, and the distribution changes to a locally concentrated distribution after a predetermined time. That is, since the concentration of the ionic impurities can be increased, it is possible to perform the analysis with higher sensitivity even by using a conventionally used analyzer such as SIMS. The local concentration of ionic impurities becomes more remarkable as the potential difference (applied voltage) is large and the time for which the potential difference occurs (DC voltage application time) is longer. On the other hand, anionic impurities such as fluorine and chlorine are concentrated on the positive voltage side (high potential side).

Further, in the above-mentioned local concentration of ionic impurities by applying a DC voltage, the degree of concentration is dramatically increased by raising the temperature of the semiconductor thin film. This is because the diffusion coefficient of ions increases when the temperature is high. Therefore, by heating the semiconductor thin film, the applied DC voltage and the voltage application time required for efficiently moving and concentrating the ionic impurities are set. Can be reduced.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a semiconductor thin film impurity concentrating apparatus and an analyzing method according to the present invention will be described in more detail with reference to the drawings.

First Embodiment As shown in FIG. 1, the impurity concentrating device 1 of the present embodiment applies a first potential to an electrode terminal 13 and a second potential to an electrode terminal. 1
DC voltage applying means 11 to be applied to the semiconductor thin film sample 7, a closed container 3 for shutting off the semiconductor thin film sample S from the outside, and an electrode terminal 13 are electrically connected and held from the back surface of the semiconductor thin film sample S in the closed container 3. It is electrically connected to the electrode (sample holding member) 5 and the electrode terminal 17, and is provided in the vicinity of or on the surface of the semiconductor thin film sample S in the closed container 3, and the vicinity of the surface of the semiconductor thin film sample is sharp. Electrode 7 having a shape
And by applying a voltage to the electrodes 5 and 7,
The impurities are concentrated by collecting the impurities near the surface of the semiconductor thin film sample S near the electrode 7.
Further, in order to monitor the DC voltage application status of the semiconductor thin film sample S, the closed container 3 has a semiconductor thin film sample monitoring window 19,
21 are provided.

Further, the semiconductor thin film sample heating means 27 is provided under the closed container 3 for the reason of shortening the time required for the high voltage application process. In addition, after heating, the semiconductor thin film sample S is cooled to fix the concentrated state of impurities in the thin film, so that the gas introducing / exhausting means 23 is provided on the side surface of the closed container 3.
25 are provided. Further, the electrode 7 is provided with a moving means 9 which moves up and down and left and right in order to accurately concentrate a target impurity on a predetermined portion of the semiconductor thin film sample. Further, an electrode attaching / detaching means 15 is provided so that the electrode 5 can be removed.

Further, in the present embodiment, after the thin film sample produced on the Si wafer is processed by the semiconductor thin film impurity concentrating device, the ions of the impurity contained in the thin film are measured by using the secondary ion mass spectrometer (SIMS). The strength was measured. Here, a principle diagram of SIMS is shown in FIG. This SIMS is 1
The primary ion irradiation system is divided into a secondary ion irradiation system and a secondary ion mass spectrometry system. First, an ion gun 39 provided in the primary ion irradiation system accelerates primary ions to an energy of several keV to several tens of keV, and an electrostatic lens is used. The surface of the sample 41 is sputter-etched with focused ions of O ₂ ⁺ , Cs ^{+ and the} like, and positive and negative secondary ions generated from the sample 41 are extracted. Next, in the secondary ion mass spectrometry system, positive and negative secondary ions generated from the sample 41 are incident on the sector magnetic field 45 through the sector electric field 43 and the slit 47. In this sector magnetic field 45, a difference in mass number of secondary ions is separated by a magnetic field, and the secondary electron multiplier 51 detects the difference, whereby elemental analysis can be performed.

Here, it is also possible to measure the element distribution in the depth direction by continuously performing the sputter etching described above. Further, the in-plane distribution of the element in a predetermined region can be measured by scanning the primary ions, and the depth direction can be repeated to measure the three-dimensional distribution.

Here, as another analysis method, a total reflection fluorescent X-ray analysis method, which is a kind of fluorescent X-ray analysis in which X-rays are irradiated onto the sample surface at a low angle and only the impurity elements on the surface are measured, By irradiating a desired measurement sample with high-speed (about MeV) hydrogen ions to bring each element contained in the sample into an excited state and analyzing the X-ray peculiar to the element emitted when the element is relaxed to the ground state The PIXE method for analyzing the elements contained in the sample, and 10 in the ultra-high vacuum ( ^{-10 -10} Torr)
AES that analyzes the elements contained in a sample by measuring the specific energy of Auger electrons generated from atoms in the solid when the solid surface is irradiated with an electron beam accelerated to 20 keV
A method or the like may be used.

An experiment of the semiconductor thin film concentrating apparatus according to the present invention was conducted using the above apparatus. The results are shown below.

Example 1 In this example, SiO formed on a Si wafer by a thermal oxidation method.
Ionic impurities in the _two membranes (2000Å) were concentrated using the device of the present invention and examined by a secondary ion mass spectrometer.

Concentration and measurement conditions Concentration conditions of thin film: potential on back surface of sample wafer (electrode 5): 0 V, potential on electrode 7: -500 V, distance between electrode 7 and sample wafer surface: 0.1 mm, closed container Space volume: 1800 cm ³ , DC voltage application time: 30 minutes, sample wafer heating: 60 ° C.-10 minutes, sample wafer cooling: 20 ° C.
-20 minutes Measurement conditions of the secondary ion mass spectrometer ...... Device: ATOMIC
A SIMS4000, primary ion beam: Ar ⁺ , accelerating voltage: 1
0 KV, beam diameter: 0.05 mmφ, scanning range: 0.5
mm × 0.5 mm, current: 0.05 μA, secondary ion accelerating voltage: 3 KV, others: use of electrospray gun As a result, Na from the SiO ₂ film surface to 50 Å,
The ionic strengths of K and Mg are 710, 420, and 23, respectively.
It was 0.

[0035] without any Comparative Examples 1-1 concentration operation was measured directly sample by secondary ion mass spectrometer in Example 1 and the same measurement conditions (sample heating, etc.), 50 Å of SiO ₂ film surface Up to N
The ionic strengths of a, K and Mg were 20, 15 and 8, respectively.

Comparative Example 1-2 Concentration and measurement were carried out under the same conditions as in Example 1 except that no DC voltage was applied, that is, the potential of the electrode 7 was set to 0 V. As a result, Na from the SiO ₂ film surface to 50 Å , K, M
The ionic strength of g was 20, 16 and 7, respectively.

Example 2 A SiO ₂ film (5 formed by LPCVD on a Si wafer)
The ionic impurities in 000Å) were concentrated using the apparatus of the present invention and examined by a secondary ion mass spectrometer.

Concentration and measurement conditions Concentration conditions of thin film: potential of back surface of sample wafer (electrode 5): 0 V, potential of electrode 7: -500 V, distance between electrode 7 and sample wafer surface: 0.1 mm, sealed container Space volume: 1800 cm ³ , DC voltage application time: 30 minutes, sample wafer heating temperature: 60 ° C.-10 minutes, sample wafer cooling: 2
0 ℃ -20 minutes Measurement condition of secondary ion mass spectrometer ...... Device: ATOMIC
A SIMS4000, primary ion beam Ar ⁺ , accelerating voltage: 10
KV, beam diameter: 0.05 mmφ, scanning range: 0.5 m
m × 0.5 mm, current: 0.05 μA, secondary ion accelerating voltage: 3 KV, others: use of electrospray gun As a result, Na from the SiO ₂ film surface to 50 Å,
The ionic strengths of K and Mg are 830, 610 and 17, respectively.
It was 0.

Comparative Example 2-1 A sample was directly measured with a secondary ion mass spectrometer under the same measurement conditions as in Example 2 without performing any concentration operation. Na, K from the SiO ₂ film surface to 50 Å , Mg had ionic strengths of 12, 9, and 4, respectively.

Comparative Example 2-2 Concentration and measurement were carried out under the same conditions as in Example 2 except that no DC voltage was applied, that is, the potential of the electrode 7 was set to 0 V. Na of the SiO ₂ film surface up to 50 Å was measured. , K, M
The ionic strength of g was 11, 9, and 4, respectively.

Example ₃ Ionic impurities in a Si ₃ N ₄ film (4000 Å) formed on a Si wafer by a plasma CVD method were concentrated by using the apparatus of the present invention and examined by a secondary ion mass spectrometer.

Concentration and measurement conditions Concentration conditions for thin film: potential on back surface of sample wafer (electrode 5): 0 V, potential on electrode 7: -800 V, distance between electrode 7 and sample wafer surface: 0.1 mm, sealed container Spatial volume: 1800 cm ³ , DC voltage application time: 30 minutes, sample wafer heating temperature: 90 ° C.-10 minutes, sample wafer cooling: 2
0 ℃ -20 minutes Measurement condition of secondary ion mass spectrometer ...... Device: ATOMIC
A SIMS4000, primary ion beam: Ar ⁺ , accelerating voltage: 1
0 KV, beam diameter: 0.05 mmφ, scanning range: 0.5
mm × 0.5 mm, current: 0.05 μA, secondary ion accelerating voltage; 3 KV, others: use of electrospray gun As a result, Na from the SiO ₂ film surface to 50 Å,
The ionic strengths of K and Mg are 1200, 850 and 5, respectively.
It was 70.

Comparative Example 3-1 A sample was directly measured with a secondary ion mass spectrometer under the same measurement conditions as in Example 3 without performing any concentration operation. Na, K from the SiO ₂ film surface to 50 Å , Mg had ionic strengths of 22, 17, and 10, respectively.

Comparative Example 3-2 Concentration and measurement were carried out under the same conditions as in Example 3 except that no DC voltage was applied, that is, the potential of the electrode 7 was set to 0 V. Na of the SiO ₂ film surface to 50 Å was measured. , K, M
The ionic strengths of g were 21, 17, and 10, respectively.

Example 4 A SiO ₂ film (250 formed on a Si wafer by a thermal oxidation method)
The ionic impurities in 0Å) were concentrated using the apparatus of the present invention and examined with a secondary ion mass spectrometer.

Concentration and measurement conditions Thin film concentration conditions: potential of the backside of the sample wafer (electrode 5): 0 V, potential of the electrode 7: +500 V, distance between electrode 7 and sample wafer surface: 0.1 mm, space of closed container Volume: 1800 cm ³ , DC voltage application time: 30 minutes, sample wafer heating: 60 ° C.-10 minutes, sample wafer cooling: 20 ° C.
-20 minutes Measurement conditions of the secondary ion mass spectrometer ...... Device: ATOMIC
A SIMS4000, primary ion beam: Ar ⁺ , accelerating voltage: 1
0 KV, beam diameter: 0.05 mmφ, scanning range: 0.5
mm × 0.5 mm, current: 0.05 μA, secondary ion accelerating voltage: 3 KV, others: using electrospray gun As a result, F, Cl from the SiO ₂ film surface to 50 Å
Had an ionic strength of 110 and 230, respectively.

Comparative Example 4-1 When a sample was directly measured by a secondary ion mass spectrometer under the same measurement conditions as in Example 4 without performing any concentration operation, F, Cl from the SiO ₂ film surface to 50 Å. Had an ionic strength of 3 and 8, respectively.

Comparative Example 4-2 Concentration and measurement were carried out under the same conditions as in Example 4 except that no DC voltage was applied, that is, the potential of the electrode 7 was set to 0 V, and F from the SiO ₂ film surface to 50 Å was measured. , Cl had ionic strengths of 3 and 8, respectively.

According to the above examples, according to the semiconductor concentrator of this embodiment, the impurities could be concentrated about 30 times. Therefore, it is considered that the analysis sensitivity is improved 30 times and the accuracy is improved considerably. Further, there is a concentration effect regardless of the type of thin film and the manufacturing method.

As described above, the sample is not acid-dissolved and the impurities are not separated and concentrated, but the direct current high voltage is applied to locally concentrate the ionic impurities in a non-contact manner, so that the contamination from the reagents and instruments is significantly increased. It can be reduced. Further, since the impurities are concentrated in the closed container, pollution from the environment can be reduced. From the above, according to the present invention, the sensitivity of ionic impurities such as Na, K, F, and Cl in the local thin film can be significantly improved as compared with the conventional method. Moreover, the operation for concentrating impurities in the thin film sample is simple, and its industrial value is great.

Second Embodiment Next, an impurity concentrating device for a semiconductor thin film sample according to a second embodiment will be described with reference to the drawings.

FIG. 4 shows an impurity concentrating device for a semiconductor thin film sample according to this embodiment. The impurity concentrating device 1 includes a closed container 3 for shutting off the semiconductor thin film sample S from the outside, and the semiconductor thin film sample S is placed on an electrode (holding member) 5 formed of a conductive material and the closed container 3 is placed. It is installed inside. Further, an electrode 7 having a sharp tip is provided in the closed container 3, and an electrode moving means 9 is attached to move the electrode 7 up, down, front and back, left and right in the closed container 3 and fix it at a desired position. Has been done. The impurity concentrating device 1 further includes a DC voltage power supply 1 as a means for generating a potential difference in the semiconductor thin film sample S.
1, and the positive electrode terminal 13 of the DC voltage power supply 11 is
It is connected to the electrode (holding member) 5 through the electrode attaching / detaching means 15 provided in the closed container 3 and the ammeter 29 for monitoring. Therefore, this electrode (holding member) 5 acts as a positive electrode. On the other hand, the negative electrode terminal 17 is the electrode 7 in the closed container 3.
Connected to The closed container 3 has monitoring windows 19 and 21 and a transparent window 31, and a laser irradiation device 33 is attached to the transparent window 31. Laser light emitted from the laser irradiation device 33 reaches the semiconductor thin film sample S on the electrode (holding member) 5 through the transparent window 31 and heats the portion of the semiconductor thin film sample S below the electrode 7.

The impurity concentrating device 1 is equipped with a gas supply means 23 and an exhaust means 25 for introducing and exhausting a cooling gas for cooling the semiconductor thin film sample S.

In the above-mentioned structure, the semiconductor thin film sample S has a silicon film formed on the surface, if necessary, and then placed on the electrode (holding member) 5 and fixed at an appropriate position in the closed container 3,
Connect with the connection terminal 15. Next, the electrode 7 is arranged at an appropriate position above the semiconductor thin film sample S, a DC voltage is applied to the electrode (holding member) 5 and the electrode 7 acting as electrodes by the DC voltage power supply 11, and the laser irradiation device 33 is used. The semiconductor thin film sample S is irradiated with laser light to heat the semiconductor thin film sample S below the electrode 7. As a result, the ionic impurities of the semiconductor thin film sample S are concentrated near the electrode 7. When the heating for a predetermined time is completed, the cooling gas is supplied from the gas supply means 23 into the closed container 3 to cool the semiconductor thin film sample S, and at the same time, the cooled gas is discharged to the outside by the exhaust means 25. After the temperature of the semiconductor thin film sample S has dropped to about room temperature, the voltage application is released, the semiconductor thin film sample S is taken out of the closed container 3, and the ionic impurities concentrated near the surface of the semiconductor thin film sample S are analyzed by physical analysis means. taking measurement.

Further, in the above configuration, the DC voltage power source 1
Electrodes (holding members) of the positive electrode terminal 13 and the negative electrode terminal 17 of 1
5 and the connection with the electrode 7 are reversed, the electrode 7 becomes a positive electrode, and anionic impurities such as halogen are concentrated near the electrode 7. A voltage changeover switch may be provided in the DC voltage power supply 11 to easily switch the connection.

As is apparent from the above, according to the semiconductor thin film concentrating device of this embodiment, the impurities in the semiconductor thin film are locally concentrated in a part of the semiconductor thin film without performing the chemical treatment operation of the semiconductor thin film. In addition, the time required for concentration is short, and the concentration can be performed easily. Therefore, by measuring the impurities that are concentrated in the semiconductor thin film, it is possible to detect a very small amount of impurities, and thus it is possible to measure impurities quickly, easily and with high sensitivity.

[Sample 1] A sample 1 was obtained by forming a 3000 Å thick silicon dioxide film on a 6-inch silicon wafer by a thermal oxidation method.

(Operation Example 1) A silicon film having a thickness of 500 Å was formed on the silicon dioxide film of Sample 1 by the CVD method, and 1
Cut out into a square of 5 mm × 15 mm, condense the ionic impurities in the silicon dioxide film according to the following conditions using the apparatus of FIG. 4, and measure the sodium ion ranging from the surface of the silicon dioxide film to 50 Å by secondary ion mass spectrometry. The ionic strength of potassium and magnesium was measured. The results are shown in Table 1.

[Concentration conditions] Potential of the electrode (holding member) 5:
0 V, potential of electrode 7: -500 V, distance between electrode 7 and sample 1 surface: 0.05 mm, volume of closed container 3: 1800 cm
³ , voltage application time: 15 minutes, heating of sample 1 by laser light: 60 ° C-10 minutes, cooling of sample 1: 20 ° C-5 minutes [Ion strength measurement conditions] Device: ATOMICA SIMS4000, primary ion beam: Ar ⁺ , Accelerating voltage: 10KV, beam diameter: 0.05mmφ, scanning range: 0.5mm × 0.5mm, current: 0.05μA, secondary ion accelerating voltage: 3KV, others: using electrospray gun (Operation example 2) sample Table 1 shows the results of measuring the ionic strength by performing the same operation as in Operation Example 1 except that the silicon film was not formed on No. 1.

(Operation Example 3) Using sample 1, the same operation as in operation example 1 was carried out except that heating with a laser was not performed in the operation of concentrating impurities. Shown in 1.

(Operational Example 4) Operational Example 1 using Sample 1 except that the impurity concentration operation was performed without applying a DC voltage.
The measurement results of the ionic strength are shown in Table 1 by performing the same operation as in (Standard Example 1) Sample 1 is used, and the operation of concentrating impurities is omitted from Operation Example 1 to measure the ionic strength. The results obtained are shown in Table 1.

[Sample 2] L on a 6 inch silicon wafer
A 4000 Å thick silicon dioxide film was formed by the PCVD method to obtain Sample 2.

(Operation Example 5) A silicon film having a thickness of 500 Å was formed on the silicon dioxide film of Sample 2 by the CVD method, and 1
Cut out into a square of 5 mm × 15 mm, condense the ionic impurities in the silicon dioxide film according to the following conditions using the apparatus of FIG. 4, and measure the sodium ion ranging from the surface of the silicon dioxide film to 50 Å by secondary ion mass spectrometry. The ionic strength of potassium and magnesium was measured. The results are shown in Table 1.

[Concentration conditions] Potential of the electrode (holding member) 5:
0 V, potential of electrode 7: -500 V, distance between electrode 7 and sample 1 surface: 0.05 mm, volume of closed container 3: 1800 cm
³ , voltage application time: 15 minutes, heating of sample 1 by laser light: 60 ° C-10 minutes, cooling of sample 2: 20 ° C-5 minutes [Ion strength measurement conditions] Same as measurement conditions in operation example 1 (operation example 6) The same operation as in Operation Example 5 was carried out except that the silicon film was not formed on Sample 2, and the results of measuring the ionic strength are shown in Table 1.

(Operational Example 7) Using Sample 2, the same operation as in Operational Example 5 was carried out except that the heating with the laser was not performed in the operation of concentrating the impurities. Shown in 1.

(Operation Example 8) Operation Example 5 except that the concentration operation of impurities was performed using Sample 2 without applying a DC voltage.
The results of ionic strength measurement performed in the same manner as in (1) are shown in Table 1. (Standard example 2) Sample 2 is used to perform the same procedure as in operation example 5 except that the concentration of impurities is omitted, and the ionic strength is measured. The results obtained are shown in Table 1.

[Sample 3] A sample 3 was obtained by forming a 5000 Å trisilicon tetranitride film on a 6-inch silicon wafer by plasma CVD.

(Operation Example 9) A silicon film having a thickness of 500 Å was formed on the trisilicon tetranitride film of Sample 3 by the CVD method,
Cut out into a 15 mm × 15 mm square, and use the device of FIG. 4 to concentrate the ionic impurities in the trisilicon tetranitride film according to the following conditions, and measure up to 50 Å from the surface of the trisilicon tetranitride film by secondary ion mass spectrometry. The ionic strength of sodium, potassium and magnesium in the range was measured. Table 1 shows the results
Shown in

[Concentration conditions] Potential of the electrode (holding member) 5:
0 V, potential of electrode 7: -800 V, distance between electrode 7 and sample 1 surface: 0.05 mm, volume of closed container 3: 1800 cm
³ , voltage application time: 15 minutes, heating of sample 1 by laser light: 90 ° C.-10 minutes, cooling of sample 3: 20 ° C.-5 minutes [Ion strength measurement conditions] Same as measurement conditions in operation example 1 (operation example 10) The same operation as in Operation Example 9 was carried out except that the silicon film was not formed on Sample 3, and the results of measuring the ionic strength are shown in Table 1.

(Operation Example 11) Using Sample 3, the same operation as in Operation Example 9 was performed except that the heating with the laser in the operation of concentrating the impurities was not performed, and the results of measuring the ionic strength are shown. Shown in 1.

(Operation Example 12) Using sample 3, the same operation as in operation example 9 was carried out except that the impurity concentration operation was performed without applying a DC voltage. It shows in Table 1.

(Standard Example 3) Table 1 shows the results of measuring the ionic strength by using Sample 3 in the same manner as in Operation Example 9 except that the concentration of impurities was omitted.

[0073]

[Table 1] [Sample 4] A silicon dioxide film having a thickness of 3000 Å was formed on a 6-inch silicon wafer by a thermal oxidation method to obtain Sample 4.

(Operation Example 13) A silicon film having a thickness of 500 Å is formed on the silicon dioxide film of Sample 4 by the CVD method,
Cut out into a 15 mm × 15 mm square, condense the halogen impurities in the silicon dioxide film according to the following conditions using the device of FIG. 4, and measure the fluorine and chlorine in the range from the surface of the silicon dioxide film to 50 Å by secondary ion mass spectrometry. Was measured. Table 2 shows the results.

[Concentration conditions] Potential of the electrode (holding member) 5:
0 V, potential of electrode 7: +700 V, distance between electrode 7 and sample 1 surface: 0.05 mm, volume of closed container 3 1800 cm
³ , voltage application time: 15 minutes, heating of sample 1 by laser light: 60 ° C.-10 minutes, cooling of sample 4: 20 ° C.-5 minutes [Ion strength measurement conditions] Same as measurement conditions in operation example 1 (operation example 14) The same operation as in Operation Example 13 was carried out except that the silicon film was not formed on Sample 4, and the results of measuring the ionic strength are shown in Table 2.

(Operation Example 15) Using Sample 4, the same operation as in Operation Example 13 was carried out except that heating with a laser was not performed in the operation of concentrating impurities. 2 shows.

(Operation Example 16) Using sample 4, the same operation as in operation example 13 was performed except that the impurity concentration operation was performed without applying a DC voltage. It shows in Table 2.

(Standard example 4) Operation example 13 using sample 4
Table 2 shows the results of the ionic strength measurement performed by omitting the concentration operation of impurities.

[0079]

[Table 2] As is clear from the above, the effect of concentrating impurities by directly applying a voltage to the semiconductor thin film sample is dramatically increased by heating the semiconductor thin film sample. Furthermore, by forming a silicon film on the surface of the semiconductor thin film sample, the heating efficiency is improved, which further increases the impurity concentration efficiency.

Third Embodiment Next, a semiconductor thin film impurity concentrating apparatus according to a third embodiment will be described with reference to the drawings.

FIG. 5 shows the semiconductor thin film impurity concentrating apparatus of this embodiment. This concentrator comprises a DC voltage applying means 11 for applying a first potential to the electrode terminal 13 and a second potential to the electrode terminal 17, and a closed container 3 for shutting off the semiconductor thin film sample S from the outside. , An electrode 5 which is connected to the electrode terminal 13 and holds the semiconductor thin film sample S in the closed container 3 from the back surface, and an electrode terminal 17, which is connected to the surface near or on the surface of the semiconductor thin film sample S in the closed container 3. And an electrode 7 having a pointed shape is provided, and by applying a DC voltage to the electrode 5 and the electrode 7, the impurities are concentrated near the surface of the semiconductor thin film sample S in the vicinity of the electrode 7 to concentrate the impurities. I am doing it.

Here, in this embodiment, a storage container 35 for the organic substance 37 is provided as a film forming means for forming a predetermined film on the surface of the semiconductor thin film sample S. The storage container 35 forms an organic material film on the surface of the semiconductor thin film sample S by generating an organic material vapor inside the closed container 3 by heating the organic material 37 stored in the container.
By thus forming the predetermined film on the surface of the semiconductor thin film sample S, it is possible to suppress the secondary contamination of the semiconductor thin film sample from the environment and to suppress the evaporation loss of the target impurities in the thin film. . Further, it is desirable to set these thin films as thick as possible from the viewpoint of suppressing secondary pollution, but if they are too thick, it takes a long time to analyze. 3000Å
In the following, the range of 100 to 2000Å is preferable, and the range of 2000Å or less, particularly 20 to 1000Å is preferable for the organic film.

In order to monitor the DC voltage application state of the semiconductor thin film sample S, the closed container 3 is provided with semiconductor thin film sample monitoring means 19 and 21. Further, heating means 27 for heating the semiconductor thin film sample S is provided for the purpose of shortening the time required for the DC voltage application process.

An ammeter may be provided in an electric circuit outside the closed container 3 in order to monitor the amount of current between the semiconductor thin film sample S and the electrodes 5 and 7 (not shown).

After heating, the semiconductor thin film sample S is cooled to fix impurities in the thin film, or in order to suppress the generation of organic vapor by cooling the organic substance, gas introducing / exhausting means 23 is provided on the side surface of the closed container. , 25 are provided. Also,
The electrode 7 is provided with a moving means 9 that moves vertically, forward and backward, and left and right in order to accurately concentrate a predetermined portion of the semiconductor thin film sample. Further, an electrode attaching / detaching means 15 is provided so that the electrode 5 can be removed.

An experiment for concentrating impurities in a semiconductor thin film was conducted using the above-mentioned apparatus. The results are shown below.

[Sample 1] Sample 1 was obtained by forming a 2500 Å thick silicon dioxide film on a 6-inch Si wafer by a thermal oxidation method.

(Operation Example 1) A naphthalene film having a thickness of 500 Å was formed on the silicon dioxide film of Sample 1 by an evaporation method, and 1
It is cut into a square of 5 mm × 15 mm, the ionic metal impurities in the silicon dioxide film are concentrated according to the following conditions by using the device of FIG. 5, and Na in the range from the surface of the silicon dioxide film to 50 Å is measured by secondary ion mass spectrometry. , K and Mg were measured for ionic strength. The results are shown in Table 3.

[Concentration conditions] Potential of the electrode (holding member) 5:
0 V, potential of electrode 7: -50 V, distance between electrode 7 and sample surface: 0 mm, volume of closed container 3: 1800 cm ³ , DC voltage application time: 15 minutes, heating of sample 1 by laser light: 6
0 ° C.-10 minutes, cooling of sample 1: 20 ° C.-5 minutes [Ion strength measurement conditions] Device: ATOMICA SIMS4000, primary ion beam: Ar ⁺ , accelerating voltage: 10 KV, beam diameter: 0.05 mmφ, scanning range: 0 0.5 mm × 0.5 mm, current: 0.05 μA, secondary ion accelerating voltage: 3 KV, others: using electrospray gun (Operation Example 2) Same as Operation Example 1 except that the naphthalene film was not formed on Sample 1. Table 3 shows the results of performing the operation and measuring the ionic strength.

(Operation Example 3) Using sample 1, the same operation as in operation example 1 was carried out except that heating with a laser was not carried out in the operation of concentrating impurities. 3 shows.

(Operation Example 4) Operation Example 1 using Sample 1 except that the impurity concentration operation was performed without applying a DC voltage.
The measurement results of the ionic strength are shown in Table 3 by performing the same operation as in (Standard Example 1) Sample 1 is used, and the operation of concentrating impurities is omitted from Operation Example 1 to measure the ionic strength. The results obtained are shown in Table 3.

[Sample 2] A sample 3 was obtained by forming a 4000 Å thick trisilicon tetranitride film on a 6-inch Si wafer by a plasma CVD method.

(Operation Example 5) A naphthalene film having a thickness of about 500Å was formed on the trisilicon tetranitride film of Sample 2 by a vapor deposition method and cut into a square of 15 mm × 15 mm. The ionic impurities in the trisilicon tetranitride film were concentrated according to the conditions, and Na, K, Mg in the range from the surface of the trisilicon tetranitride film to 50 Å by secondary ion mass spectrometry.
Was measured. The results are shown in Table 3.

[Concentration conditions] Potential of the electrode (holding member) 5:
0 V, potential of electrode 7: -80 V, distance between electrode 7 and sample surface: 0 mm, closed container 3 volume: 1800 cm ³ , DC voltage application time: 15 minutes, heating of sample 2 by laser light: 9
0 ° C.-10 minutes, cooling of sample 2: 20 ° C.-5 minutes [Ion strength measurement conditions] Same as the measurement conditions in Operation Example 1 (Operation Example 6) Operation Example 5 except that the naphthalene film was not formed on Sample 2. Table 3 shows the results of measuring the ionic strength by performing the same operation as described above.

(Operational Example 7) Using Sample 2, the same operation as in Operational Example 5 was carried out except that the heating with a laser was not carried out in the operation of concentrating the impurities. 3 shows.

(Operation Example 8) Operation Example 5 using Sample 2 except that the impurity concentration operation was performed without applying a DC voltage.
The measurement results of the ionic strength are shown in Table 3 by performing the same operation as in (Standard Example 2) Sample 2 is used, and the operation of concentrating impurities is omitted from Operation Example 5 to measure the ionic strength. The results obtained are shown in Table 3.

[Sample 3] LPC on a 6-inch Si wafer
A sample 3 was obtained by forming a 4000 Å thick silicon dioxide film by the VD method.

(Operation Example 9) A carbon film having a thickness of 200 Å was formed on the silicon dioxide film of Sample 3 by a vapor deposition method.
Cut into squares of 15 mm × 15 mm, condense halogen impurities in the silicon dioxide film according to the following conditions using the device of FIG. 5, and measure the fluorine and chlorine in the range from the surface of the silicon dioxide film to 50 Å by secondary ion mass spectrometry. Was measured. The results are shown in Table 3.

[Concentration conditions] Potential of the electrode (holding member) 5:
0 V, potential of electrode 7: +70 V, distance between electrode 7 and sample surface: 0 mm, volume of closed container 3: 1800 cm ³ , DC voltage application time: 15 minutes, heating of sample 3 by laser light: 6
0 ° C.-10 minutes, cooling of sample 3: 20 ° C.-5 minutes [Ion strength measurement conditions] Same as the measurement conditions in Operation Example 1 (Operation Example 10) Operation Example 9 except that no carbon film was formed on Sample 3. Table 3 shows the results of measuring the ionic strength by performing the same operation as described above.

(Operational Example 11) Using sample 3, the same operation as in operational example 9 was carried out except that heating with a laser was not carried out in the operation of concentrating impurities. 3 shows.

(Operation Example 12) Using sample 3, the same operation as in operation example 9 was performed except that the impurity concentration operation was performed without applying a DC voltage. It shows in Table 3.

(Standard Example 3) Table 3 shows the results obtained by measuring the ionic strength using the sample 3 except that the concentration of impurities was omitted from the operation example 9.

As is clear from the above, the effect of concentrating impurities by applying a DC voltage to the semiconductor thin film sample is
It is dramatically increased by heating the semiconductor thin film sample. Furthermore, by forming an organic film on the surface of the semiconductor thin film sample, secondary contamination from the environment is suppressed and
Since the evaporation loss of the target impurities in the thin film can be suppressed, the analytical sensitivity and accuracy of the impurities can be greatly improved.

[0104]

[Table 3]

[0105]

As described above, according to the impurity concentrating device for a semiconductor thin film and the impurity analyzing method therefor according to the present invention,
The ionic impurities of the semiconductor thin film can be locally concentrated near the surface by a simple operation without chemical treatment, making it easy to measure impurities in trace amounts below the detection sensitivity, and its industrial value is extremely high. Is large.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a configuration of an impurity concentrating device for a semiconductor thin film according to a first embodiment of the present invention.

FIG. 2 is a graph showing the concentration of ionic impurities in a semiconductor thin film according to the present invention, where the vertical axis represents the impurity concentration and the horizontal axis represents the distance from the semiconductor thin film surface to which a negative voltage is applied,
Line A shows the concentration of cation impurity sodium before the application of voltage, and line B shows the concentration of sodium cation impurity after the application of voltage.

FIG. 3 is a diagram for explaining the principle of SIMS.

FIG. 4 is a conceptual diagram showing a configuration of an impurity concentrating device for a semiconductor thin film according to a second embodiment of the present invention.

FIG. 5 is a conceptual diagram showing a configuration of an impurity concentrating device for a semiconductor thin film according to a third embodiment of the present invention.

[Explanation of symbols]

 S Semiconductor thin film sample 1 Impurity concentrator 3 Sealed container 5 Electrode (holding member) 7 Electrode 9 Electrode moving means 11 DC voltage power supply 13 Electrode terminal (positive electrode terminal) 15 Electrode attaching / detaching means 17 Electrode terminal (negative electrode terminal) 19 Semiconductor thin film sample monitoring Window 21 Semiconductor thin film sample monitoring window 23 Gas introduction means 25 Gas discharge means 27 Heating means 29 Ammeter 31 Transparent window 33 Laser irradiation device 35 Organic substance storage container 37 Organic substance 39 Ion gun 41 Sample 43 Sector electric field 45 Sector magnetic field 47 Slit 49 Deflection Electrode 51 Secondary electron multiplier

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuhiro Tomita 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Toshiba Research & Development Center (72) Inventor Takashi Yoshida Komukai-shi, Kawasaki-shi, Kanagawa 1 Incorporated Toshiba Research and Development Center (72) Inventor Isao Suzuki Komukai Toshiba Town, Kouki-ku, Kawasaki City, Kanagawa Prefecture 1 Incorporated Toshiba Research and Development Center (72) Inventor Masaaki Morita Komukai, Saiwai-ku, Kawasaki City, Kanagawa Prefecture Toshiba Town 1 Toshiba Research Consulting Co., Ltd.

Claims (10)

[Claims] 1. An electrode for causing a potential difference in a semiconductor thin film to concentrate ionic impurities in the semiconductor thin film to a part of the semiconductor thin film due to the potential difference, and a sealed container for shielding the semiconductor thin film from the outside. An impurity concentrating device for a semiconductor thin film, comprising: 2. An apparatus for concentrating impurities contained in a semiconductor thin film, wherein a first electric potential is applied to a first electrode terminal, and the first electric potential is applied to the first electrode terminal.
DC voltage applying means for applying a second electric potential different from the electric potential of the first electrode terminal to the second electrode terminal, a closed container for blocking the semiconductor thin film from the outside, and an electrical connection to the first electrode terminal, A first electrode for holding the semiconductor thin film sample in the container from one surface and an electrode electrically connected to the second electrode terminal, in the vicinity of the other surface of the semiconductor thin film sample in the closed container or on the other surface. A second electrode provided on the surface, and applying a voltage to the first and second electrodes to collect the impurities near the other surface of the semiconductor thin film sample near the second electrode. An impurity concentrating device for a semiconductor thin film, wherein the impurities are concentrated by means of: 3. The impurity concentration device for a semiconductor thin film according to claim 2, wherein the first and second electrodes are detachable. 4. The impurity concentrating device for a semiconductor thin film according to claim 2, further comprising heating means for heating the semiconductor thin film sample held by the first electrode. 5. The semiconductor thin film impurity concentrating device according to claim 1, further comprising film forming means for forming a predetermined film in the closed container. 6. The impurity concentration device for a semiconductor thin film according to claim 4, wherein the heating means irradiates the surface of the semiconductor thin film with light to heat it. 7. The semiconductor thin film impurity concentrating device according to claim 1, further comprising a physical analysis means for detecting the concentrated impurities after the impurities are concentrated. 8. A method for analyzing impurities by concentrating impurities in a semiconductor thin film, wherein a voltage is applied to the semiconductor thin film sample to locally collect and concentrate the impurities, and the concentrated semiconductor is condensed. A method for analyzing impurities in a semiconductor thin film, which comprises analyzing impurities in a thin film sample. 9. The method for analyzing impurities in a semiconductor thin film according to claim 8, wherein a predetermined film is formed in advance on the other surface of the semiconductor thin film sample. 10. A secondary ion mass spectrometry method, a total reflection X-ray fluorescence analysis method, and a PIX method for impurity analysis of the semiconductor thin film sample.
The method for analyzing impurities in a semiconductor thin film according to claim 8 or 9, wherein the method is an E method or an AES method.