JP4845786B2 - Vacuum exhaust apparatus, semiconductor manufacturing apparatus, and vacuum processing method - Google Patents

Description

The present invention relates to a vacuum exhaust apparatus, a semiconductor manufacturing apparatus, and a vacuum processing method, and more particularly to a vacuum processing method for stably forming a high-performance semiconductor element on a semiconductor substrate, a glass substrate, a plastic substrate, or the like.

  In the course of studying a semiconductor manufacturing method for the purpose of further improving the performance and yield of a semiconductor device, the present inventor uses an ultra-high purity as a processing gas when a turbo molecular pump is used in an exhaust system. Even when processing is performed with great care to prevent impurities from being mixed using a vacuum processing chamber having a surface that uses gas and suppresses degassing, for example, when a thin film constituting a semiconductor element is formed, It has been found that impurities are mixed and hinder the improvement of the characteristics of the semiconductor element.

  Therefore, as a result of diligent investigation of this cause, the gas molecules once exhausted from the exhaust side of the turbo molecular pump to the vacuum processing chamber for manufacturing the thin film, the impurity gas existing on the exhaust side of the turbo molecular pump, etc. are back-diffused. It has been found that this is because it is mixed into the thin film when the thin film is formed. That is, it has been found that in order to achieve higher performance and higher yield of the semiconductor element, an evacuation system that prevents back diffusion of such impurities and the like is required.

The present invention has been completed on the basis of the above knowledge, and provides a vacuum exhaust apparatus, a semiconductor manufacturing apparatus, and a vacuum processing method capable of stably manufacturing a high-performance semiconductor element with a high yield. Objective.

The vacuum exhaust apparatus of the present invention is an exhaust apparatus for exhausting the inside of a vacuum chamber, and includes a turbo molecular pump and an auxiliary pump connected to an exhaust side of the turbo molecular pump, and the turbo molecular pump A gas introduction part for introducing Ar gas between the auxiliary pump and the Ar gas, wherein the Ar gas flow rate is 5% or more and less than 17.5% of the gas flow rate supplied to the vacuum chamber, A configuration in which the inside of the vacuum chamber is evacuated while introducing Ar gas from the introduction portion, and impurity gas, moisture, or particles present on the exhaust side of the turbo molecular pump is prevented from back-diffusing into the vacuum chamber. It is characterized by that.
The vacuum processing method of the present invention is a vacuum processing for processing a substrate in the vacuum chamber while exhausting the inside of the vacuum chamber by a turbo molecular pump and an auxiliary pump connected to an exhaust side of the turbo molecular pump. The flow rate of Ar gas is 5% or more and less than 17.5% of the flow rate of the gas supplied to the vacuum chamber, Ar gas is introduced between the turbo molecular pump and the auxiliary pump, The back diffusion of impurity gas, moisture, or particles from the exhaust side of the turbo molecular pump to the vacuum chamber is prevented.
Furthermore, the vacuum processing method of the present invention is a vacuum processing for processing a substrate in the vacuum chamber while exhausting the inside of the vacuum chamber by a turbo molecular pump and an auxiliary pump connected to an exhaust side of the turbo molecular pump. The flow rate of Ar gas is 5% or more and less than 17.5% of the flow rate of the gas supplied to the vacuum chamber, Ar gas is introduced between the turbo molecular pump and the auxiliary pump, A molecular flow region to a viscous flow region is provided between the exhaust side of the turbo molecular pump and the auxiliary pump to prevent back diffusion of impurity gas, moisture, or particles from the exhaust side of the turbo molecular pump to the vacuum chamber. It is characterized by.
The vacuum exhaust apparatus of the present invention is an exhaust apparatus for exhausting the inside of a vacuum chamber, and includes a turbo molecular pump and an auxiliary pump connected to an exhaust side of the turbo molecular pump, and the turbo molecular pump A gas introduction part for introducing N ₂ gas between the auxiliary pump and the auxiliary pump , wherein the flow rate of the N ₂ gas is 2% or more and less than 8% of the flow rate of the gas supplied to the vacuum chamber, While introducing N ₂ gas from the introduction part, the inside of the vacuum chamber was evacuated to prevent back diffusion of impurity gas, moisture, or particles present on the exhaust side of the turbo molecular pump into the vacuum chamber. It is characterized by having a configuration.
The vacuum processing method of the present invention is a vacuum processing for processing a substrate in the vacuum chamber while exhausting the inside of the vacuum chamber by a turbo molecular pump and an auxiliary pump connected to an exhaust side of the turbo molecular pump. In this method, the flow rate of N ₂ gas is 2% or more and less than 8% of the flow rate of gas supplied to the vacuum chamber, and N ₂ gas is introduced between the turbo molecular pump and the auxiliary pump , The back diffusion of impurity gas, moisture, or particles from the exhaust side of the turbo molecular pump to the vacuum chamber is prevented.
Furthermore, the vacuum processing method of the present invention is a vacuum processing for processing a substrate in the vacuum chamber while exhausting the inside of the vacuum chamber by a turbo molecular pump and an auxiliary pump connected to an exhaust side of the turbo molecular pump. In this method, the flow rate of N ₂ gas is 2% or more and less than 8% of the flow rate of gas supplied to the vacuum chamber, and N ₂ gas is introduced between the turbo molecular pump and the auxiliary pump , A molecular flow region to a viscous flow region is provided between the exhaust side of the turbo molecular pump and the auxiliary pump to prevent back diffusion of impurity gas, moisture, or particles from the exhaust side of the turbo molecular pump to the vacuum chamber. It is characterized by.

The predetermined gas is preferably an inert gas, a gas supplied to the vacuum chamber, a component of the gas, or a mixed gas of these and an inert gas. Further, the flow rate of the predetermined gas is preferably 10% or less of the flow rate of the gas supplied to the vacuum chamber.
The semiconductor manufacturing apparatus of the present invention includes at least a vacuum chamber and the above-described vacuum exhaust apparatus of the present invention connected to the vacuum chamber, and processes the substrate in the vacuum chamber.
The semiconductor processing apparatus of the present invention has at least a vacuum chamber and the vacuum exhaust apparatus of the present invention connected to the vacuum chamber, and deposits a metal, semiconductor, or insulator material in the vacuum chamber. It is characterized by.
Further, the vacuum chamber and at least the vacuum exhaust apparatus of the present invention connected to the vacuum chamber are provided, and surface treatment of a metal, a semiconductor, or an insulator material is performed in the vacuum chamber.
A method for manufacturing a semiconductor device of the present invention is characterized in that a thin film constituting a semiconductor element is formed using the vacuum processing method of the present invention.
In addition, a semiconductor element is formed over a semiconductor substrate, a glass substrate, or a plastic substrate using the vacuum processing method of the present invention.
Furthermore, the substrate is processed using the vacuum processing method of the present invention.

  Moreover, it is preferable that the vacuum chamber and the connection member have a chromium oxide passivated film or a fluorinated passivated film formed on the inner surface.

  As an example of the semiconductor manufacturing apparatus of the present invention, the operation of the present invention will be described through an experiment conducted using the sputtering apparatus shown in FIG.

In FIG. 1, reference numeral 101 denotes a vacuum chamber for performing sputtering film formation in which the inner surface is subjected to chromium oxide passivation treatment, and the amount of released water is about 1 × 10 ⁻⁷ Torr · L / sec. The vacuum chamber 101 is connected to the intake side of the turbo molecular pump 103 via a pipe 102, and the exhaust side of the pump 103 is connected to the roughing pump 105 via a flexible pipe 104. In addition, a process gas is supplied to the vacuum chamber 101 via the mass flow controller 110, and further, a pipe 106, a needle valve 107, a quadrupole mass spectrometer 108, and a roughing pump 109 are connected to the vacuum chamber 101. 101 is configured to perform mass spectrometry of the gas in 101.

  An introduction unit 114 for introducing a predetermined gas is provided on the exhaust side of the turbo molecular pump 103, and the predetermined gas is introduced via the mass flow controller 111.

  In the vacuum chamber 101, high-frequency power is applied to an electrode (not shown) from a high-frequency power source 112 through a matching box 113, and plasma is generated in the vacuum chamber.

Using the sputtering apparatus of FIG. 1, Ar gas having a moisture concentration of 1 ppb is supplied to the vacuum chamber 101 via the mass flow controller 110 as a process gas (gas supplied to the vacuum chamber), and a roughing pump having various exhaust capabilities is used. FIG. 2 shows the results of measuring the H ₂ O concentration in the vacuum chamber with a quadrupole mass spectrometer when evacuated.

As shown in FIG. 2, it was found that although the H ₂ O concentration changes depending on the Ar flow rate and the exhaust speed of the roughing pump, a considerably large amount of water is contained in the process gas atmosphere. This water is considered to be the result of the reverse diffusion of the water released from the flexible piping 104 on the exhaust side of the turbo molecular pump.

Next, Ar gas having a moisture concentration of 1 ppb is supplied to the vacuum chamber 101 as a process gas while introducing N ₂ gas from the gas introduction unit 114 on the exhaust side of the turbo molecular pump through the mass flow controller 111. FIG. 3 shows the results of measuring the H ₂ O concentration in the vacuum chamber with a quadrupole mass spectrometer. Compared with FIG. 2, the H ₂ O concentration is greatly reduced by supplying N ₂ gas to the exhaust side of the turbo molecular pump 111, and further, the N ₂ gas flow rate is set to about 10% of the process gas flow rate. It was found that the vacuum chamber was reduced to about 10 ppb, and an extremely clean atmosphere could be obtained in the vacuum chamber.

  The details of this reason are not clear at present, but can be considered as follows. That is, by introducing an inert gas between the turbo molecular pump and the auxiliary pump, the molecular flow region is changed to the viscous flow region between the exhaust side of the turbo molecular pump and the auxiliary pump, and the turbo molecular pump is temporarily outside the vacuum chamber. This is probably because the process gas molecules exhausted in this way are moved by the viscous flow as they are and are exhausted by the auxiliary pump, so that back diffusion hardly occurs.

In consideration of the possibility of back diffusion into the vacuum chamber even though it is a small amount, as the predetermined gas, in order to suppress the influence on the processing in the vacuum chamber as much as possible even if reverse diffusion, an inert gas, or It is preferable to use a gas contained in the process gas or a mixed gas thereof. As the inert gas, Ar, N ₂ gas or the like is preferably used. Furthermore, on the inner surface of the connecting member (for example, piping) between the molecular turbo pump and the auxiliary pump, a chromium oxide passivated film or a fluorinated passivated film having a low moisture adsorption amount and excellent desorption characteristics is formed. Is preferred.

  Further, the impurity concentration of the predetermined gas is preferably 1 ppm or less, more preferably 1 ppb or less, but this purity may be less than this depending on the purity of the process gas, the performance of the semiconductor element, or the purpose of use. Needless to say. Further, the amount of the predetermined gas introduced is preferably 10% or less of the process gas flow rate. This is because if the gas flow rate exceeds 10% of the process gas flow rate, sufficient exhaust characteristics of the turbo molecular pump cannot be obtained. This is thought to be because the pressure on the exhaust side of the turbo molecular pump increases and the compression ratio decreases.

  In the present invention, the predetermined gas introduction part may be provided in the exhaust port part of the turbo molecular pump as described above, or may be provided in a connection member (for example, a pipe) with the auxiliary pump.

  In order to fabricate a higher performance semiconductor element, it is preferable to form a chromium oxide passivated film or a fluorinated passivated film not only on the connecting member but also on the inner surface of a vacuum chamber or other piping.

  The vacuum evacuation apparatus and the vacuum processing method of the present invention include various vacuum related apparatuses such as sputtering, vacuum deposition, dry etching, ion implantation apparatus and other semiconductor manufacturing apparatuses, analyzers such as AES and SIMS, and metals. It is preferably applied to film formation of semiconductor and insulator materials, surface treatment, and the like.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

  In this example, an Al film was produced using the sputtering apparatus shown in FIG. 1 and evaluated.

A silicon substrate is placed on a substrate electrode (not shown) of the sputtering chamber (vacuum chamber) 101 in FIG. 1, and the inside of the chamber is evacuated to 10 ⁻⁸ Torr. Ar gas having a moisture concentration of 1 ppb or less was introduced at 200 sccm through the mass flow 110, high-frequency power was applied at a pressure in the chamber of 10 mTorr, and an Al film was formed to a thickness of about 100 nm. At this time, the moisture concentration in the film forming atmosphere was measured with a quadrupole mass spectrometer.

A predetermined gas (Ar) of 0 to 50 sccm was introduced through the mass flow controller 111 with the film forming conditions kept constant, and the relationship between the Ar gas introduction flow rate, the moisture content in the chamber, and the Al resistivity was examined. The results are shown in FIG. In FIG. 4, the horizontal axis represents the Ar flow rate introduced from the mass flow controller 111, and the vertical axis represents the moisture content in the chamber and the specific resistance of the Al film. As is apparent from the figure, the water content and specific resistance decrease with an increase in the Ar gas flow rate, become minimal at 1/10 (20 sccm) of the Ar gas flow rate introduced into the chamber, and further, the Ar gas flow rate introduced from the mass flow controller 111. It was found that increasing the amount increases both the water content and the specific resistance.
As shown in FIG. 4, in the range of 10 sccm (0.5 / 10 = 5%) or more to 35 sccm (1.75 / 10 = 17.5%), the water concentration is significantly reduced compared to the other ranges ( 0.1 ppm or less). In particular, in the range of 15 sccm (0.75 / 10 = 7.5%) or more and 30 sccm (1.5 / 10 = 15%), it is 0.01 ppm or less, which shows that it is further excellent.

  Further, when the amount of oxygen in the Al film was measured by SIMS (secondary ion mass spectrometer), it was confirmed that the change in oxygen concentration coincided with the change in specific resistance, and became minimum at an Ar flow rate of 20 sccm.

  As is apparent from the above experimental results, it is understood that a high-quality thin film is formed by supplying gas between the turbo molecular pump exhaust side and the auxiliary pump.

  In this example, a silicon nitride film was grown using a plasma CVD apparatus having a structure similar to that shown in FIG.

A substrate in which a metal electrode is formed on a glass substrate is used, and a substrate temperature of 300 ° C., SiH ₄ gas = 100 sccm, NH ₃ = 200 sccm, and N ₂ = 200 sccm are introduced into the chamber via a mass flow controller. A silicon nitride film was deposited to a thickness of 300 nm by applying high-frequency power at a pressure of 100 Pa.

While keeping the film forming conditions constant, only the total flow rate is maintained while maintaining a flow rate ratio of 1: 2: 2 in which a mixed gas of SiH ₄ , NH ₃ , and N ₂ is introduced between the turbo molecular pump and the auxiliary pump. Was introduced between 0 and 70 sccm, and the withstand voltage of the formed silicon nitride film and the number of particles of 0.3 μm or more adhering to the substrate were examined. FIG. 5 shows the result.

It was found that when the total flow rate of 30 sccm was introduced into the exhaust side of the turbo molecular pump, the total number of particles was the smallest and the withstand voltage was the highest. This is because by introducing gas to the exhaust port side of the turbo molecular pump, the reaction products generated when SiH ₄ and NH ₃ are decomposed in the plasma are completely exhausted without back diffusion into the chamber. This is probably because

  Next, when no gas was introduced into the exhaust side of the turbo molecular pump and when 30 sccm, which is the optimum value, was introduced, 50 consecutive films were formed under the same conditions, and the variation in dielectric strength was examined. The results are shown in FIG. As shown in FIG. 6, the variation in the dielectric breakdown voltage when no gas was introduced was ± 10%, whereas the variation when 30 sccm was introduced was suppressed to ± 2%, and the average breakdown voltage could be increased. It was.

  According to the present invention, it becomes possible to remarkably increase the cleanliness of the vacuum chamber, and as a result, it becomes possible to perform highly accurate vacuum processing, and thus it is possible to stably provide a semiconductor device or the like with a high yield. Become.

It is a conceptual diagram of the sputtering device which shows an example of the semiconductor manufacturing apparatus of this invention. Is a graph showing the flow rate and H ₂ O concentration of the gas supplied into the vacuum chamber. Is a graph showing the relationship between the flow rate of the predetermined gas to be introduced in H ₂ O concentration and the turbo molecular pump exhaust side of the vacuum chamber. It is a graph which shows the relationship between Al specific resistance and the flow volume of Ar gas introduce | transduced into a turbo-molecular pump exhaust side. It is a graph which shows the relationship between the withstand voltage of a silicon nitride film, and the flow volume of Ar gas introduce | transduced into the turbo-molecular pump exhaust side. It is a graph which shows the dispersion | variation in a withstand voltage.

Explanation of symbols

101 vacuum chamber,
102 piping,
103 turbomolecular pump,
104 Flexible piping,
105 roughing pump,
106 piping,
107 needle valve,
108 quadrupole mass spectrometer,
109 roughing pump,
110, 111 mass flow controller,
112 high frequency power supply,
113 matching box,
114 A predetermined gas introduction part.

Claims (16)

An exhaust device for exhausting the inside of the vacuum chamber,
A turbo molecular pump and an auxiliary pump connected to the exhaust side of the turbo molecular pump;
A gas introduction part for introducing Ar gas between the turbo molecular pump and the auxiliary pump;
The flow rate of the Ar gas is 5% or more and less than 17.5% of the flow rate of the gas supplied to the vacuum chamber,
While introducing Ar gas from the introduction part, the inside of the vacuum chamber was evacuated to prevent back diffusion of impurity gas, moisture, or particles present on the exhaust side of the turbo molecular pump into the vacuum chamber. An evacuation apparatus characterized by having a configuration. An exhaust device for exhausting the inside of the vacuum chamber,
A turbo molecular pump and an auxiliary pump connected to the exhaust side of the turbo molecular pump;
A gas introduction part for introducing N ₂ gas is provided between the turbo molecular pump and the auxiliary pump,
The flow rate of the N ₂ gas is 2% or more and less than 8% of the flow rate of the gas supplied to the vacuum chamber,
While introducing N ₂ gas from the introduction part, the inside of the vacuum chamber is evacuated to prevent back diffusion of impurity gas, moisture, or particles present on the exhaust side of the turbo molecular pump into the vacuum chamber. An evacuation apparatus characterized by having a configuration as described above. The vacuum according to claim 1 or 2, wherein a chromium oxide passivated film or a fluorinated passivated film is formed on an inner surface of a connecting member used for connecting the turbo molecular pump and the auxiliary pump. Exhaust system. The evacuation apparatus according to any one of claims 1 to 3, wherein a back diffusion is prevented when a process gas is supplied to the vacuum chamber. 5. A semiconductor manufacturing apparatus comprising at least a vacuum chamber and the vacuum exhaust apparatus according to claim 1 connected to the vacuum chamber, wherein the substrate is processed in the vacuum chamber. . 6. The semiconductor manufacturing apparatus according to claim 5, wherein the vacuum chamber has a chromium oxide passivated film or a fluorinated passivated film formed on an inner surface thereof. A vacuum chamber and at least the vacuum exhaust device according to any one of claims 1 to 4 connected to the vacuum chamber, and forming a metal, semiconductor, or insulator material in the vacuum chamber. The processing apparatus characterized by the above-mentioned. A vacuum chamber and at least the vacuum exhaust apparatus according to any one of claims 1 to 4 connected to the vacuum chamber, and performing a surface treatment of a metal, a semiconductor, or an insulator material in the vacuum chamber. The processing apparatus characterized by the above-mentioned. A vacuum processing method for processing a substrate in the vacuum chamber while exhausting the inside of the vacuum chamber by a turbo molecular pump and an auxiliary pump connected to an exhaust side of the turbo molecular pump,
The flow rate of Ar gas is 5% or more and less than 17.5% of the flow rate of the gas supplied to the vacuum chamber,
Ar gas is introduced between the turbo molecular pump and the auxiliary pump to prevent back diffusion of impurity gas, moisture, or particles from the exhaust side of the turbo molecular pump to the vacuum chamber. Processing method. A vacuum processing method for processing a substrate in the vacuum chamber while exhausting the inside of the vacuum chamber by a turbo molecular pump and an auxiliary pump connected to an exhaust side of the turbo molecular pump,
The flow rate of Ar gas is 5% or more and less than 17.5% of the flow rate of the gas supplied to the vacuum chamber,
Ar gas is introduced between the turbo molecular pump and the auxiliary pump, the molecular flow region to the viscous flow region between the exhaust side of the turbo molecular pump and the auxiliary pump,
A vacuum processing method characterized by preventing back diffusion of impurity gas, moisture, or particles from the exhaust side of the turbo molecular pump into the vacuum chamber. A vacuum processing method for processing a substrate in the vacuum chamber while exhausting the inside of the vacuum chamber by a turbo molecular pump and an auxiliary pump connected to an exhaust side of the turbo molecular pump,
The flow rate of N ₂ gas is 2% or more and less than 8% of the flow rate of the gas supplied to the vacuum chamber,
N ₂ gas is introduced between the turbo molecular pump and the auxiliary pump to prevent back diffusion of impurity gas, moisture, or particles from the exhaust side of the turbo molecular pump to the vacuum chamber. Vacuum processing method. A vacuum processing method for processing a substrate in the vacuum chamber while exhausting the inside of the vacuum chamber by a turbo molecular pump and an auxiliary pump connected to an exhaust side of the turbo molecular pump,
The flow rate of N ₂ gas is 2% or more and less than 8% of the flow rate of the gas supplied to the vacuum chamber,
N ₂ gas is introduced between the turbo molecular pump and the auxiliary pump, and the molecular flow region is changed to the viscous flow region between the exhaust side of the turbo molecular pump and the auxiliary pump,
A vacuum processing method characterized by preventing back diffusion of impurity gas, moisture, or particles from the exhaust side of the turbo molecular pump into the vacuum chamber. The vacuum processing method according to claim 9, wherein reverse diffusion is prevented when a process gas is supplied to the vacuum chamber. A thin film forming a semiconductor element is formed by using the vacuum processing method according to claim 9. A semiconductor device manufacturing method, wherein a semiconductor element is formed on a semiconductor substrate, a glass substrate, or a plastic substrate by using the vacuum processing method according to claim 9. A method for manufacturing a semiconductor device, wherein a substrate is processed using the vacuum processing method according to claim 9.

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