JP4941514B2 - Process gas supply apparatus and film forming apparatus - Google Patents

Description

The present invention relates to a processing gas supply apparatus and a film forming apparatus provided in, for example, a semiconductor manufacturing apparatus.

In general, in a manufacturing process of a semiconductor integrated circuit, a desired element is obtained by repeatedly performing film formation and pattern etching on a substrate such as a semiconductor wafer or glass. As the semiconductor integrated circuit is miniaturized and highly integrated, the processing line width and the gate width are made narrower, and the film thickness tends to be reduced in accordance with the demand for a multilayer structure of the integrated circuit.
In particular, in an integrated circuit having a multi-layer structure, circuit elements are stacked in multiple layers. Therefore, if the control of the film thickness in each layer is insufficient, the influence is spread to the upper layer, for example, the surface As a result, it becomes impossible to realize an appropriate integrated circuit.
Usually, in a semiconductor manufacturing apparatus, in order to control the gas flow rate, a flow rate controller with high accuracy of flow rate control, for example, a mass flow controller is used.

By the way, the above-described mass flow controller has a very good flow rate controllability with respect to the gas flow, but as described above, when further integration and multi-layering are further promoted, the film thickness to be formed becomes thinner, and Those having high controllability of the film thickness are required.
However, in the above-described mass flow controller, for very small gas flow rates, it is very difficult to control with high accuracy due to the structure thereof, and film formation with a sufficiently controlled film thickness is performed. It has become difficult. For example, when a gate electrode or wiring having a film thickness of several hundreds of liters is formed, there is a problem that it is very difficult to control the film thickness because it is difficult to control the flow rate of the minute gas.

The present invention has been devised to pay attention to the above problems and to effectively solve them. An object of the present invention is to provide a processing gas supply apparatus and a film forming apparatus capable of supplying a minute amount of gas with high accuracy.

The invention according to claim 1 includes a gas discharge passage for discharging the control target gas that is a processing gas stored in the control target gas source, and a gas use system for flowing the carrier gas stored in the carrier gas source. A connected carrier gas passage, a plurality of auxiliary pipes connected so as to span between the carrier gas passage and the gas discharge passage, and a span between the plurality of auxiliary pipes having a predetermined volume. to a quantitative pipe connected to a valve mechanism for switching the communication state of the quantitative pipe selectively between the two passages, and a valve drive unit that controls the operation of the valve mechanism, comprising the A processing gas supply device. This makes it possible to supply a predetermined amount of the control target gas in the metering tube to the working system.

In this case, at the time of non-use of the control target gas For example, the valve mechanism is previously filled by passing a controlled target gas in the quantification canal communicates the gas exhaust passage and quantification tube, at the time of gas used, the valve mechanism, the The metering pipe and the carrier gas passage are communicated to supply the control target gas filled in the metering pipe to the gas use system. Therefore, a minute amount of gas corresponding to the preset capacity of the metering tube can be accurately supplied to the gas use system.
Further, when a gas use system requires a capacity that is several times larger than the capacity of the metering tube, for example, filling the metering tube with the control target gas and carrying it in the future may be repeated a plurality of times.

  Such a trace gas supply apparatus can be applied as a processing gas supply system of a semiconductor manufacturing apparatus, for example. When applied to a semiconductor manufacturing apparatus, for example, during the film formation process, it is necessary to avoid the occurrence of pressure fluctuations in the processing container. A state in which the flow is performed at a constant pressure and a state in which the carrier gas is constantly flowed at a constant pressure to the semiconductor manufacturing apparatus side through the carrier gas passage are also provided. Then, if necessary, the valve mechanism is operated to selectively connect the metering tube to the gas discharge passage side or to the carrier gas passage, and fill the metering tube. Gas is supplied to the semiconductor manufacturing apparatus when necessary (during processing). According to this, since the gas is not shut off to the semiconductor manufacturing apparatus and is always supplied at a constant pressure during processing and during non-processing, there is no pressure fluctuation in the processing container. .

According to the processing gas supply apparatus and the film forming apparatus of the present invention, the following excellent operational effects can be exhibited.
Since the metering tube is used to supply the control target gas filled therein to the gas using system by the carrier gas, it is possible to control the minute flow rate with high accuracy.
Further, by applying this trace gas supply device (process gas supply device) to the process gas supply system of the semiconductor manufacturing apparatus, the flow rate of the trace process gas can be controlled with high accuracy. Therefore, when a very thin film is formed, the film thickness can be controlled with high accuracy.
In particular, film formation can be performed without causing pressure fluctuations in the processing vessel by switching the communication of the metering tube in the state where the gas of the same pressure flows in the carrier gas passage and the gas discharge passage. The film thickness can be controlled with high accuracy.

It is a figure which shows the state which provided the trace gas supply apparatus which concerns on this invention in the gas usage system. It is a figure which shows the kind of metering tube. It is explanatory drawing for demonstrating switching operation | movement of the valve | bulb in this invention apparatus.

Hereinafter, an embodiment of a processing gas supply apparatus and a film forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram showing a state in which a trace gas supply device (processing gas supply device) according to the present invention is provided in a gas use system, and FIG. 2 is a diagram showing types of metering tubes. Here, a case where a Ti film is formed using a semiconductor manufacturing apparatus that performs a predetermined process such as a film forming process on a substrate such as a semiconductor wafer or an LCD will be described as an example of a gas using system.
As shown in the figure , a trace gas supply device 2 which is a processing gas supply device according to the present invention is connected to a single-wafer type semiconductor manufacturing apparatus 4 as a gas use system. Is supplied as a control target gas.
The semiconductor manufacturing apparatus 4 includes, for example, an aluminum processing container 6 whose inner surface is anodized, and a mounting table 8 on which a substrate W such as a semiconductor wafer is mounted is provided. For example, a resistance heater 10 is built in the mounting table 8 as a heating means, and the substrate W on the mounting table 8 can be heated and maintained at a predetermined temperature.

Further, an exhaust port 12 connected to a vacuum exhaust system (not shown) is provided at the bottom of the container so that the inside of the processing container 6 can be evacuated evenly from the periphery of the mounting table 8. A gate valve 14 that is opened and closed when the substrate W is carried in and out is provided on the side wall of the processing container 6.
A shower head 16 for uniformly supplying a predetermined gas into the processing container 6 at the time of film formation, for example, is provided on the ceiling portion of the processing container 6. Ports 16A and 16B are provided. An NH ₃ gas supply system 18 for supplying, for example, NH ₃ (ammonia) gas as a reaction gas required for film formation is connected to one gas introduction port 16B, and the other gas introduction port 16A is connected to the above-described gas introduction port 16B. Thus, for example, TiCl ₄ (titanium tetrachloride) gas can be supplied as a processing gas.

This trace gas supply device 2 includes an N ₂ gas source 20 as a carrier gas source filled with, for example, N ₂ gas as a carrier gas, and a TiCl ₄ gas source 22 as a control target gas source filled with TiCl ₄ as a processing gas. Have. As the carrier gas, in addition to N ₂ gas, other inert gases such as Ar gas and He gas can be used.
The N ₂ gas source 20 and one gas inlet 16A of the shower head 16 are connected by a carrier gas passage 24, and the carrier gas passage 24 on the outlet side of the N ₂ gas source 20 has a A regulator 26 is provided for sending out the N ₂ gas in the N ₂ gas source 20 at a constant pressure.

On the other hand, TiCl _4, since the room temperature is liquid, TiCl ₄ is in the gas source 22 and the TiCl ₄ is stored in a liquid state, the temperature adjustment mechanism consisting of a heater or the like on the periphery of the TiCl ₄ gas source 22 28 is provided to heat the liquid TiCl ₄ at a constant temperature, so that TiCl ₄ gas having a constant pressure can be delivered.
A gas discharge passage 30 is connected to the TiCl ₄ gas source 22, and this gas discharge passage 30 is connected to a factory exhaust duct having a substantially atmospheric pressure (not shown), for example.

  Between the carrier gas passage 24 and the gas discharge passage 30, a metering tube 32, which is a feature of the present invention, is connected in parallel. Specifically, the metering pipe 32 is connected and communicated between two auxiliary pipes 34 and 36 connected so as to span between the passages 24 and 30. At both ends of the metering tube 32, flanges 32A and 33A are provided. The flanges 34A and 36A provided on the auxiliary tubes 34 and 36 are airtightly detachable with bolts or the like. The metering tube 32 has an inner diameter and a length determined in advance with high accuracy, and is set so that the internal capacity is a predetermined volume.

  The communication state of the metering pipe 32 is controlled by a valve mechanism 38 including a plurality of valves interposed in the auxiliary pipes 34 and 36 and both the passages 24 and 30, for example, selectively communicated with both the passages 24 and 30. It has come to be able to do. Specifically, the valve mechanism 30 includes a first valve 38A provided between the connection points of the auxiliary pipes 34 and 36 to the carrier gas passage 24, and a connection of the both auxiliary pipes 34 and 36 to the gas discharge passage 30. The second valve 38B provided between the points, the third and fourth valves 38C and 38D provided on both sides of the connection point A to the one auxiliary pipe 34 of the metering pipe 32, and the other auxiliary pipe 36 of the metering pipe 32. It is comprised by the 5th and 6th valve | bulb 38E, 38F provided in the both sides of the connection point B to. In this case, the third and fourth valves 38C and 38D and the fifth and sixth valves 38E and 38F provided across the connection points A and B are moved as close to the connection points A and B as possible. The tube capacity between the valves 38C and 38D and the tube capacity between the valves 38E and 38F are reduced. Opening / closing of the valves 38A to 38F is controlled by a valve driving unit 41 under the control of a main control unit (not shown) of the semiconductor manufacturing apparatus 4.

As shown in FIG. 2, the metering tube 32 is prepared in advance with a plurality of types having different internal capacities, for example, by varying the inner diameter, and corresponds to the flow rate of the processing gas required at the time of film formation. Those are appropriately selected and used. For example, FIG. 2 (A) shows a 10 cc metering tube, FIG. 2 (B) shows a 30 cc metering tube, and FIG. 2 (C) shows a 50 cc metering tube. It should be noted that, strictly speaking, the capacity of each metering pipe is the auxiliary pipe capacity between the third and fourth valves 38C and 38D and the auxiliary pipe capacity between the fifth and sixth valves 38E and 38F. Therefore, the gas flow rate can be controlled with high accuracy by the total volume of the gas. The tube capacity is only an example, and it is needless to say that the tube capacity is not limited to the above.
Further, in the portion where the TiCl ₄ gas flows, a heater 40 such as a tape heater (shown by a broken line) is used in order to prevent the TiCl ₄ gas from being condensed and liquefied in the middle of the passage or in the pipeline. Are provided along the passages 24 and 30, the auxiliary pipes 34 and 36, and the metering pipe 32.
In the illustrated example, six valves are formed separately. However, if a multi-way valve in which a plurality of valves are incorporated into one block body is used, the overall configuration can be greatly simplified.

Next, the case where the film forming process is performed by the semiconductor manufacturing apparatus using the trace gas supply apparatus configured as described above will be described.
First, prior to starting the film formation process, based on past experience, when TiCl ₄ gas is supplied at a certain pressure, how much flow is formed and how thick the film is formed. Therefore, the metering tube 32 having a gas amount corresponding to the target thickness for film formation is attached to the trace gas supply device 2. For example, if it is assumed that a target thickness is 100 mm and a Ti film having a thickness of 100 mm requires 10 cc of TiCl ₄ gas at the constant pressure, 10 cc shown in FIG. This is mounted using a metering tube for the purpose.
Now, when the preliminary preparation is completed in this way, the substrate W is placed on the mounting table 8 in the processing container 6 and heated to a predetermined processing temperature, and at the same time, the processing container 6 is evacuated. To maintain a predetermined processing pressure. The processing temperature is, for example, 600 ° C., and the processing pressure is in the range of 10 mTorr to 10 Torr, for example, about 300 mTorr.

First, before the actual film forming process is performed, as shown in FIG. 3A, the first, fourth, and sixth valves 38A, 38D, and 38F are opened, and the second, third, and fifth valves are opened. 38B, 38C, and 38E are closed. As a result, the carrier gas is directly introduced into the processing container 6 through the carrier gas passage 24 as shown by an arrow 42, while the TiCl ₄ gas as the processing gas is introduced into the gas discharge passage as shown by an arrow 44. From 30, the gas flows into the metering tube 32 through the fourth valve 38 </ b> D, and flows again into the gas discharge passage 30 through the sixth valve 38 </ b> F to be discharged. In this state, the metering tube 32 always flows in a state filled with a constant amount, that is, 10 cc of TiCl ₄ gas.
Here, the carrier gas is controlled so that the carrier gas always flows at a constant pressure into the carrier gas passage 24, and at the same time, the TiCl ₄ gas constantly flows into the gas discharge passage 30 at a constant pressure by the temperature adjustment mechanism 28. Controlled to flow. And the pressure in both the passages 24 and 30 is adjusted so that it may become substantially the same pressure. Here, for example, the temperature adjusting mechanism 28 generates liquid by heating the liquid TiCl ₄ to about 75 ° C., and the heater 40 passes through the passage at about 80 ° C. in order to prevent condensate liquefaction on the way. Heating.

In addition, a certain amount of NH ₃ gas is supplied as a reaction gas from a separate NH ₃ gas supply system 18 into the processing vessel 6.
Under such circumstances, in order to actually perform the film forming process, as shown in FIG. 3B, the open / closed state of each valve is switched in the opposite manner to the case of FIG. These valve switching operations are all performed simultaneously. That is, the first, fourth, and sixth valves 38A, 38D, and 38F are closed, and the second, third, and fifth valves 38B, 38C, and 38E are opened. As a result, as shown by an arrow 46, the carrier gas flows into the metering tube 32 from the carrier gas passage 24 through the third valve 38C, and again into the carrier gas passage 24 through the fifth valve 38C. To the processing vessel 6. At this time, the TiCl ₄ gas filled in the metering tube 32 is pushed out by the carrier gas and flows into the processing container 6.

On the other hand, the TiCl ₄ gas is discharged to the factory exhaust duct side directly, that is, without flowing through the metering pipe 32, as shown by an arrow 48.
As described above, 10 cc of TiCl ₄ under a constant pressure filled in the metering tube 32 can be supplied into the processing container 6, and a film having a thickness corresponding to this flow rate, for example, 100 Å is formed with high accuracy. It becomes possible.
As described above, the flow rate of the processing gas corresponding to the target film thickness can be supplied with high accuracy by using the corresponding metering tube, and the film thickness can be controlled with high accuracy. In particular, with this metering tube, it is possible to easily control a minute flow rate that could not be controlled with high accuracy by conventional mass flow controllers. Can be accurately controlled.

Further, since each valve is switched in a state where both the carrier gas and TiCl ₄ gas are flowed at a constant pressure, the pressure fluctuation of the supply gas does not occur in the processing vessel 6 even if the valve is switched. Therefore, the process conditions do not fluctuate, and the film thickness can be controlled with higher accuracy than this point.
In the above embodiment, the valves are switched at the same time. For example, in the state shown in FIG. 3A, the fourth and sixth valves 38D and 38F are closed and the second valve 38B is opened at the same time. 3 is temporarily isolated while the TiCl ₄ gas is filled in the chamber 32, and then the third and fifth valves 38C and 38E are opened and the first valve 38A is closed at the same time as shown in FIG. 3B. You may make it transfer. That is, any valve switching operation may be performed as long as the TiCl ₄ gas can be transported into the processing container 6 through the metering tube 32.

In addition, for example, when it is assumed that 30 cc of TiCl ₄ gas is necessary to form a film having a target film thickness, a 30 cc metering tube shown in FIG. 3B may be used. However, using the 10 cc metering tube shown in FIG. 3A, the valve switching operation described above is intermittently repeated, for example, three times, so that 30 cc of TiCl ₄ is supplied to the processing vessel 6 as a whole. It may be. That is, it is only necessary that the valve switching operation is intermittently performed an appropriate number of times to supply the necessary TiCl ₄ gas as a whole. As described above, when the film is formed by intermittently supplying the gas multiple times, it is equivalent to annealing when the film forming gas is not supplied. It is promoted to improve the film quality.
In addition, in the case where other gas supply system, for example, NH ₃ gas which is a reaction gas here, is required to control the micro flow rate with high accuracy, a trace gas supply device having a structure similar to that of the TiCl ₄ system is separately provided. In the same manner as described above, the valve switching operation may be performed to perform the same control.

Furthermore, although the case where a Ti film is formed has been described here as an example, the present invention apparatus can of course be applied to any type of film formation such as a TiN film or a TiSi film.
Furthermore, the apparatus of the present invention is not limited to a single wafer type semiconductor manufacturing apparatus, but can also be applied to a batch type semiconductor manufacturing apparatus capable of processing a large number of substrates at once. Further, the substrate is not limited to a semiconductor wafer, and can be applied to a glass substrate, an LCD substrate, and the like.

2 Trace gas supply equipment 4 Semiconductor manufacturing equipment (gas use system)
6 Processing vessel 16 Shower head 20 N ₂ gas source (carrier gas source)
22 TiCl ₄ gas source (control target gas source)
24 Carrier gas passage 26 Regulator 30 Gas discharge passage 32 Metering tube 34, 36 Auxiliary tube 38 Valve mechanism 38A-38F Valve W Substrate

Claims (8)

A gas discharge passage for discharging a control target gas that is a processing gas stored in the control target gas source, a carrier gas passage connected to a gas use system for flowing the carrier gas stored in the carrier gas source, and A plurality of auxiliary tubes connected to span between the carrier gas passage and the gas discharge passage, and a metering tube having a predetermined volume and connected to span between the plurality of auxiliary tubes; A processing gas supply apparatus comprising: a valve mechanism that selectively switches a communication state of the metering pipe between the passages; and a valve drive unit that controls the operation of the valve mechanism . The gas used systems are facilities to semiconductor manufacturing equipment processing for the substrate, the control target gas processing gas according to claim 1, characterized in that the process gas used when performing processing for the substrate Feeding device. The valve mechanism, at the time of untreated filling the process gas into the quantitative pipe by flowing the process gas into the quantitative pipe, the process gas which has been filled in the quantitative pipe transports by the carrier gas during processing process gas supply apparatus according to claim 2, wherein the operative to. The valve mechanism operates to flow the carrier gas directly to the semiconductor manufacturing apparatus during non-processing, and to discharge the processing gas from the control target gas source without flowing through the metering tube during processing. process gas supply apparatus請Motomeko 2 or 3, wherein a. The valve mechanism is
  A first valve provided between connection points of the plurality of auxiliary pipes to the carrier gas passage; a second valve provided between connection points of the plurality of auxiliary pipes to the gas discharge passage; The third and fourth valves provided on both sides of the connection point to one auxiliary pipe, and the fifth and sixth valves provided on both sides of the connection point of the metering pipe to the other auxiliary pipe. The processing gas supply device according to any one of claims 1 to 4, wherein the processing gas supply device is provided. 6. The processing gas supply apparatus according to claim 5, wherein the third valve, the fourth valve, the fifth valve, and the sixth valve are arranged as close as possible to the corresponding connection points. The processing gas supply device according to any one of claims 1 to 6, wherein the pressure in the carrier gas passage and the pressure in the gas discharge passage are set to be the same pressure. A film forming apparatus, comprising: a processing container for storing therein a substrate to be processed using a processing gas; and the processing gas supply device according to claim 1.

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