JPH11287743A - Thermal desorbing/analyzing chamber for wafer process monitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform thermal desorption analysis stably and to analyze the entire substrate, e.g. a silicon wafer, as a sample. SOLUTION: In the analyzing chamber 14, a hot plate 22 incorporating a heater 24 and an electrode 23 is set in a vacuum tank 15 to be evacuated and a sample 20 carried into the vacuum tank 15 is mounted on the hot plate 22. When the heater 24 is heated while being attracted electrostatically to the electrode 23, temperature of the sample 20 increases and gas is emitted from substances adhering to the surface thereof. The vacuum tank 15 is coupled with an analyzer 16 for analyzing gas contained in the vacuum atmosphere. Since the sample 20 is heated by the hot plate 22, the kind and quantity of substances adhering to the surface of a sample, i.e., a large area substrate, can be analyzed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching apparatus for etching a substance on a semiconductor using plasma, a CVD (Chemical Vapor Deposition) apparatus for forming a film, a sputtering apparatus, and an ashing apparatus for ashing a resist. And a technology for monitoring the process.

[0002]

2. Description of the Related Art In order to analyze a substance attached to a substrate such as a silicon wafer, the attached substance is directly dissolved in addition to a chemical device such as ion chromatography which dissolves the attached substance with a solvent and analyzes the solution. XPS to analyze (X-ray Photo
electron spectroscopy), AES (Auger Electron Spectroscopy)
troscopy), SIMS (Secondary ion Mass Spectrometr)
y), FTIR (Fourier Transformed Infra-Red spectro
scopy) is used.

[0003] Since a chemical analyzer such as an ion chromatography performs solution analysis, it is not usually used in combination with a process device using a vacuum atmosphere, but is usually constituted as an independent device. On the other hand, the surface analysis apparatus is not only used in an independent apparatus configuration, but also has a good connection with a vacuum atmosphere, and thus may be experimentally used in a configuration combined with a wafer processing apparatus.
However, in the case of an experimental apparatus, the substrate itself is rarely analyzed, and a small piece is usually analyzed.

[0004] Among the surface analyzers, the thermal desorption analyzer has a simple structure and is suitable for analyzing substances adhering to a substrate. Conventional thermal desorption analyzer is 60-100mm
It has a quartz tube with a diameter of 10 to 30 m.
After being carried into a quartz tube as small pieces of m-square and placed on a sample table made of quartz material or metal material, the sample is heated in a vacuum atmosphere by an infrared lamp arranged outside the quartz tube,
The analysis of the gas released and released from the sample is performed. Generally, the sample stage is slightly larger than the sample to be analyzed in order to minimize the heat capacity and the released gas.

When such a thermal desorption analyzer is connected to a process apparatus, the substrate is supported by being floated in a vacuum with point-contact pins and a quartz window in order to efficiently heat only the sample. Through an infrared lamp from outside.

However, since a substrate such as a silicon wafer has a light transmission characteristic, even in the case of irradiating infrared rays, light in the far-infrared region is transmitted, and the efficiency for raising the temperature of the substrate is low. Very bad.

Further, when the adhered substance absorbs infrared rays and generates heat, it is difficult to control the temperature of the adhered substance because the infrared absorption rate differs if the adhered substance is different even if the same heating conditions are set. Or the sample is heated unevenly.

Further, although the substrate is held by using pins in a vacuum atmosphere, the temperature can be raised rapidly, but the substrate cannot be rapidly cooled due to the heat insulating effect of the vacuum, so that the substrate is overheated. In such a case, there is a problem that it is necessary to rely on a natural temperature drop due to radiation loss, and it is difficult to control the temperature.

As described above, in the conventional thermal desorption analyzer technology, when the entire substrate is used as a sample, a point contact pin is used as a sample holding mechanism, and an infrared lamp is used. Since it was used as a heating source, it was very difficult to control the temperature of the sample.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages of the prior art, and has as its object to provide a thermal desorption analysis chamber capable of performing analysis using the whole substrate as a sample. An object of the present invention is to provide a vacuum processing apparatus using the thermal desorption analysis chamber.

[0011]

Means for Solving the Problems To solve the above problems, the invention according to claim 1 comprises a vacuum tank capable of evacuating,
A thermal desorption analysis chamber having an analyzer for analyzing gas contained in a vacuum atmosphere in the vacuum chamber, wherein a hot plate with a built-in heater is provided in the vacuum chamber, and the hot plate is carried into the vacuum chamber. The sample is placed on a hot plate, the sample is heated by the heater, and gas is released from a substance attached to the sample.

The invention according to claim 2 is the thermal desorption analysis chamber according to claim 1, wherein the hot plate has an electrode, a voltage is applied to the electrode, and the sample is placed on the hot plate. It is characterized in that it can be heated while being adsorbed.

According to a third aspect of the present invention, there is provided the thermal desorption analysis chamber according to any one of the first to second aspects, wherein the heater and the electrode are provided in an insulator made of boron nitride. And the sample is configured to be arranged on the insulator surface.

According to a fourth aspect of the present invention, there is provided the thermal desorption analysis chamber according to any one of the first to third aspects, wherein the vacuum chamber is provided with a cooling mechanism for cooling the hot plate. It is characterized by having been done.

According to a fifth aspect of the present invention, there is provided a vacuum processing apparatus, wherein the thermal desorption analysis chamber according to any one of the first to fourth aspects and a process chamber for processing the sample in a vacuum atmosphere. Are connected to a transfer chamber capable of vacuum evacuation, so that the sample processed in the process chamber is carried into the thermal desorption analyzer via the transfer chamber.

The present invention is configured as described above, and has a vacuum chamber capable of evacuating and an analyzer for analyzing a gas in a vacuum atmosphere in the vacuum chamber. A hot plate with a built-in heater is provided in the vacuum chamber.When the sample carried in the vacuum chamber is placed on the hot plate and the heater is energized, the sample is heated in a vacuum atmosphere and Gas is released.

The gas is configured to be analyzed by an analyzer. As described above, since the sample is placed on the hot plate and the sample is heated, the whole large substrate such as a silicon wafer can be used as the sample.

If an electrode for electrostatic attraction is built in such a hot plate, the sample can be brought into close contact with the surface of the hot plate in a vacuum atmosphere, so that the heat transfer efficiency between the sample and the hot plate can be improved. And rapid heating becomes possible, and the temperature controllability of the sample is improved.

If a cooling mechanism is provided in the vacuum chamber in which the sample is placed so that the hot plate can be cooled, the sample can be cooled via the hot plate, so that the sample can be rapidly cooled. And the temperature controllability of the sample is further improved.

The thermal desorption analysis chamber using a hot plate described above and a process chamber for processing a sample surface in a vacuum atmosphere and forming a thin film or etching are connected to a transfer chamber capable of evacuating. When a vacuum processing apparatus is configured, a sample processed in the process chamber can be carried into the thermal desorption analysis chamber without being exposed to the atmosphere. Therefore, it is possible to immediately analyze a sample that has been subjected to etching or the like, and to perform accurate analysis because a gas that poses a problem when exposed to the atmosphere is not adsorbed on the sample surface. Is possible.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a thermal desorption analysis chamber of the present invention will be described together with a multi-chamber type vacuum processing apparatus of the present invention. Referring to FIG. 1, reference numeral 2 denotes a vacuum processing apparatus of the present invention, which includes a transfer chamber 10, a cassette chamber 11, an infrared spectroscopic measurement chamber 12, a process chamber 13, and a thermal desorption analysis chamber 14. doing.

The cassette chamber 11 and the infrared spectrometer 12
, The process chamber 13 and the thermal desorption analysis chamber 14 are arranged around the transfer chamber 10 and are connected to the transfer chamber 10 in an airtight manner.
It is configured such that the insides of 1, 12, 13, and 14 can be individually evacuated.

When the vacuum processing apparatus 2 is used, a vacuum atmosphere is previously set in the inside, only the cassette chamber 11 is opened to the atmosphere, a predetermined number of substrates are mounted on the cassette, and placed in the cassette chamber 11. After shutting off the atmosphere inside the cassette chamber 11 from the atmosphere, the cassette chamber 11 is evacuated and connected to the inside of the transfer chamber 10 when a predetermined pressure is reached.

A transfer robot (not shown) is provided in the transfer chamber 10 and takes out one substrate from the cassette chamber 11 and carries it into the process chamber 13. If the process chamber 13 is a sputtering apparatus here, after the substrate is loaded, the internal atmosphere of the process chamber 13 is cut off from the internal atmosphere of the transfer chamber 10, and
The target in 3 is sputtered to grow a thin film such as a metal thin film on the substrate surface. When the thin film has been formed to a predetermined thickness, the substrate is unloaded from the process chamber 13 and returned to the cassette chamber 11.

Next, the unprocessed substrate in the cassette chamber 11 is carried into the process chamber 13 and a thin film is formed subsequently. After the thin film is formed on all of the substrates disposed in the cassette chamber 11, the internal atmosphere of the transfer chamber 10 is cut off from the internal atmosphere of the cassette chamber 11, the cassette chamber 11 is opened to the atmosphere, and the process is completed. The removed substrate is taken out together with the cassette.

As described above, when the substrate is processed normally, the infrared spectroscopy measurement chamber 12 and the thermal desorption analysis chamber 14 are not used, but when examining the stability of the process or when a process abnormality occurs. In the case of occurrence, the infrared spectrometry room 12 and the thermal desorption analysis room 14 are used as the substrate. here,
A case will be described in which there is an abnormality during the formation of a thin film in the process chamber 13 and the attached substance is analyzed using the thermal desorption analysis chamber 14.

FIG. 2 shows an example of the thermal desorption analysis chamber 14 of the present invention, which has a vacuum chamber 15 and an analyzer 16 such as a quadrupole mass spectrometer. The thermal desorption analysis chamber 14 has a vacuum chamber 15 airtightly connected to the transfer chamber 10.

A vacuum evacuation system (not shown) is connected to the vacuum chamber 15. When the thermal desorption analysis chamber 14 is used, first, the internal atmosphere of the vacuum chamber 15 is cut off from the internal atmosphere of the transfer chamber 10. In this state, the inside of the transfer chamber 10 and the vacuum chamber 15 is evacuated by the evacuation system, and a high vacuum atmosphere is set in advance.

After the substrate in which the processing in the process chamber 13 is abnormal is taken out by the substrate transfer robot in the transfer chamber 10, the atmosphere inside the vacuum chamber 15 is connected to the transfer chamber 10 and Bring in.

A table 21 is fixed on the bottom wall in the vacuum chamber 15, and a cooling mechanism 28 is provided in the table 21. A hot plate 22 is disposed on the table 21, and the loaded substrate is used as a sample 20 as a hot plate 22.
After being placed on the transfer chamber 10, the atmosphere inside the vacuum chamber 15 is
Shield from the internal atmosphere.

The hot plate 22 is made of boron nitride (PB).
N: an insulator 23 made of pyrolitic Boron Nitride);
A heater 24 and an electrode 25;
Is disposed near the bottom surface near the base 21 in the insulator 23, and the electrode 25 is disposed in the insulator 23 on the opposite side to the heater 24, near the surface of the insulator 23.

Sample 2 placed on hot plate 22
0 is in contact with the insulator 23, and when a voltage is applied to the electrode 25 in that state, an electrostatic attraction force is generated between the electrode 25 and the sample 20, and the sample 20 is electrostatically attracted to the surface of the insulator 23.
(Here, it is assumed that two electrodes 25 are used, and positive and negative voltages are applied to each electrode 25).

In this state, the sample 20 is in close contact with the surface of the insulator 23, and the heat conduction efficiency between the insulator 23 and the sample 20 is increased. Therefore, when the heater 24 is energized and the hot plate 22 is heated, the sample 20 is heated by heat conduction from the insulator 23.

When the heat conduction efficiency between the sample 20 and the hot plate 22 is high, the temperature of the sample 20 and the temperature of the hot plate 22 are highly consistent. 20 can be controlled.

FIG. 3 is a graph showing the relationship between the temperature of the hot plate 22 and the temperature of the sample 20 electrostatically adsorbed on its surface. The horizontal axis is the hot plate temperature, the vertical axis is the substrate temperature (the temperature of the sample 20), and the four curve groups L are
It is a graph at the time of using four hot plates 22 of the same structure. From this curve group L, although there are individual differences,
The temperature of each hot plate 22 matches well with the temperature of the sample 20, and the temperature error between each hot plate 22 is also 400 ° C.
Within the following temperature range, it is within ± 4 ° C.

The hot plate 22 is provided with a temperature measuring element (not shown) (for example, a CA thermocouple), which detects the temperature of the hot plate 22 and automatically controls the amount of electricity supplied to the heater 24. By doing so, the temperature of the hot plate 22 is controlled, and as a result, the temperature of the sample 20 can be precisely controlled.

When controlling the temperature of the sample 20, a cooling mechanism 28 for cooling the hot plate 22 is used in addition to the heater 24. When the hot plate 22 is overheated, the cooling mechanism 28 is operated. If the hot plate 22 is cooled immediately, the temperature of the sample 20 can be controlled more precisely.

As described above, when the sample 20 is heated using the hot plate 22, gas is released from the adhered substance on the surface of the sample 20 as the temperature of the sample 20 rises. An analyzer 16 such as a quadrupole mass spectrometer is hermetically connected to the vacuum chamber 15, and the analyzer 16 is provided with an exhaust port 31. The exhaust port 31 is connected to a vacuum exhaust system (not shown) so that the inside of the analyzer 16 can be evacuated. The gas released into the vacuum chamber 15 is evacuated to a vacuum In addition to being evacuated outside the vacuum chamber 15 by the system, after entering the analyzer 16, it is also evacuated by a vacuum exhaust system connected to the analyzer 16.

The analyzer 16 is connected to a computer (not shown) by a terminal group 32 so that the gas that has entered the analyzer 16 is detected by the analyzer 16 and the type and amount of the gas can be analyzed by the computer. Is configured.

When the temperature of the sample 20 rises slowly, the sample 2
Since gas is slowly released from the attached substance of 0,
The analyzer 16 can record the type and amount of gas in association with the temperature and heating time of the sample 20.

In this case, for example, a substance (gas) that is detected at a low temperature in the sample 20 in the initial stage of heating is a substance that has been physically adsorbed (adhered) to the surface of the sample 20 and constitutes the surface of the sample 20. It is considered that the chemical bonding with the substance is weak. Conversely, a substance detected after the sample 20 is heated to a high temperature
It is considered that (gas) had a strong chemical bond with the substance constituting the surface of the sample 20.

When the process chamber 13 is an etching apparatus, a residue of an etching target remains on the surface of the sample 20 depending on the etching conditions. In the separation analysis chamber 14, a large detection peak is obtained at a low temperature in the early stage of heating, and a detection peak at a high temperature is small. Conversely, when the input power at the time of etching is large, the detection peak at a low temperature is small, and the detection peak at a high temperature is large.

As described above, by using the thermal desorption analysis chamber 14 of the present invention, it is possible to examine what kind of substance is adhered on the sample 20 and in what state it is adhered. It becomes possible.

When the temperature of the sample is controlled by heating the lamp as in the prior art, the uniformity of the temperature is set to 400 ° C. ± 10 ° C.
Although it was very difficult to reduce the temperature to below ° C., according to the thermal desorption analysis chamber 14 of the present invention, highly accurate and uniform temperature control of the sample 20 is possible. Further, since rapid heating and rapid cooling of the sample 20 are possible, analysis according to the property of the attached substance can be performed.

In the prior art in which an infrared lamp is disposed outside the vacuum chamber and heated, it is necessary to provide a quartz window in the vacuum chamber to introduce infrared light. However, the present invention does not require a quartz window. is there. Therefore, there is no instability of the heating conditions due to the contamination of the quartz window. Thus, the thermal desorption analysis chamber 14 of the present invention
Thus, it is possible to precisely set the heating conditions of the sample 20.

Before the analysis of the sample 20 in the thermal desorption analysis chamber 14 of the present invention, the sample 2 is stored in the infrared spectroscopic measurement chamber 12.
If 0 is carried in, infrared spectroscopy such as Fourier transform infrared spectroscopy can be performed on the same sample 20.

In the vacuum processing apparatus 2 described above, the process chamber 13 is a sputter apparatus or an etching apparatus. However, the process chamber 13 is not limited to this. In addition to a thin film removing device such as an ashing device, a device that processes a substrate in a vacuum atmosphere can be widely used.

The analyzer 16 provided in the thermal desorption analysis chamber 14 of the present invention is not limited to mass spectrometry.
It broadly includes a device capable of analyzing gas generated when a sample is heated in a vacuum atmosphere.

[0049]

According to the present invention, stable thermal desorption analysis can be performed. The whole substrate such as a silicon wafer can be analyzed as a sample.

[Brief description of the drawings]

FIG. 1 shows an example of a vacuum processing apparatus of the present invention.

FIG. 2 shows an example of the thermal desorption analysis chamber of the present invention.

FIG. 3 is a graph showing the relationship between the temperature of a hot plate used in the thermal desorption analysis chamber of the present invention and the temperature of a sample thereon.

[Explanation of symbols]

14: Thermal desorption analysis room 15: Vacuum chamber 16:
Analysis device 20 Sample 22 Hot plate 25 Electrode

Continuation of the front page (72) Inventor Naoki Mizutani 2500 Hagizono, Chigasaki City, Kanagawa Prefecture Inside Japan Vacuum Engineering Co., Ltd.

Claims (5)

[Claims] 1. A thermal desorption analysis chamber having a vacuum chamber capable of evacuating and an analyzer for analyzing a gas contained in a vacuum atmosphere in the vacuum chamber, wherein a heater is built in the vacuum chamber. A hot plate is provided, the sample carried into the vacuum chamber is placed on the hot plate, the sample is heated by the heater, and gas is released from the attached substance of the sample. Characterized thermal desorption analysis room. 2. The apparatus according to claim 1, wherein said hot plate has an electrode, and a voltage is applied to said electrode so that said sample can be heated while adsorbing said sample on said hot plate. Thermal desorption analysis room. 3. The apparatus according to claim 1, wherein the heater and the electrode are provided in an insulator made of boron nitride, and the sample is arranged on the surface of the insulator. Item 3. The thermal desorption analysis chamber according to any one of Items 2. 4. A cooling mechanism for cooling the hot plate is provided in the vacuum chamber.
The thermal desorption analysis chamber according to any one of claims 1 to 3. 5. The thermal desorption analysis chamber according to any one of claims 1 to 4, and a process chamber for processing the sample in a vacuum atmosphere are connected to a transfer chamber capable of evacuating, A vacuum processing apparatus, wherein a sample processed in a process chamber is carried into the thermal desorption analyzer via the transfer chamber.