JP3247581B2 - Gas supply device for semiconductor manufacturing apparatus and its supply method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas supply apparatus of a semiconductor manufacturing apparatus for performing, for example, a film forming process and an etching process on a semiconductor substrate, and a method of supplying the same.
In particular, it is used when performing processing in a short time.

[0002]

2. Description of the Related Art In a conventional semiconductor manufacturing apparatus, for example, a CVD apparatus for forming a film on a semiconductor substrate, SiH4 is used for forming a polysilicon film, and WF6 is used for forming a W film.
Is used as a material gas for processing. In the case of an etching apparatus that performs an etching process, the process is performed using a halogen-based material gas.

FIG. 4 schematically shows a configuration of a general film forming apparatus represented by a CVD apparatus. In this apparatus, a semiconductor substrate 101 on which a film is formed is processed in a processing chamber 102.
Is stored inside. The housed semiconductor substrate 101 is heated by the heater 103 to a temperature required for the film forming process.

The inside of the processing chamber 102 is depressurized by a pump 106 via a valve 104 and a pressure controller 105, and controlled by a pressure controller 105 to a pressure required for a film forming process.

[0005] A cylinder 107 is provided in the processing chamber 102.
Then, a material gas necessary for the film forming process is supplied through a pressure adjusting valve 108, a valve 109, a mass flow controller (MFC) 110 for adjusting a flow rate, and a valve 111. The material gas supplied into the processing chamber 102 is deposited on the semiconductor substrate 101 by the shower head 112.

[0006] In recent years, as the diameter of semiconductor substrates has increased, semiconductor manufacturing apparatuses have taken the form of single-wafer processing in which a large number of semiconductor substrates are processed one at a time instead of batch processing. It is becoming possible.

In order to increase the processing capacity (throughput) of an apparatus for performing such single-wafer processing, it is necessary to shorten the processing time per sheet. For this reason, conventionally, the processing time is shortened by selecting the processing conditions, for example, the flow rate of the material gas, so as to increase the film forming rate and the etching rate.

[0008] For example, in the case of the apparatus shown in FIG.
110. However, the MFC 110 has an elaborate flow sensor inside, and feeds back the signal of the sensor to the valve 11.
By controlling the opening degree of 1, the flow rate of the material gas is controlled. For this reason, the control of the flow rate of the material gas in a short time is greatly affected by the responsiveness and controllability of the MFC 110, and it is difficult to perform precise control for several seconds without cost.

Further, since the flow rate sensor used in the MFC 110 is susceptible to an external environment, for example, temperature, there is a problem that it is very difficult to maintain controllability of the processing.

[0010]

As described above, conventionally, it is difficult to supply a material gas with good controllability in a short time processing, and the controllability of the processing is stable because it is easily affected by the external environment. There were problems such as not.

Accordingly, the present invention provides a semiconductor manufacturing method capable of supplying a material gas with good controllability even in a short time process without being affected by an external environment, and improving controllability of the process. It is an object of the present invention to provide a gas supply device for a device and a method for supplying the gas.

[0012]

In order to achieve the above object, a gas supply apparatus for a semiconductor manufacturing apparatus according to the present invention includes a gas supply apparatus for supplying a processing material gas to a processing chamber of a semiconductor manufacturing apparatus. A container for storing a constant amount of the material gas required for processing at least one semiconductor substrate, and a pressure gauge for measuring a pressure of the material gas in the container, and a gas discharge unit side of the container. Degree of opening of provided valve
Is supplied from the container to the processing chamber by adjusting
The pressure change rate of the material gas to be
It is configured to be controlled to be constant .

Further, in the gas subjected <br/> supply method of a semiconductor manufacturing apparatus of the present invention, stored a certain amount of material gas required for processing at least one semiconductor substrate into the container, the container While measuring the pressure of the material gas of the above with a pressure gauge, the material gas stored in the container, the gas discharge unit of the container
By adjusting the opening of the valve provided on the side,
Do not control so that the rate of pressure change in the container is almost constant.
Meanwhile, the semiconductor substrate is supplied to a processing chamber in which the semiconductor substrate is stored.

[0014]

According to the present invention, the above-mentioned means makes it possible to stably supply a constant amount of material gas required for one process, so that the flow rate of material gas in a short time can be controlled with high precision. It is possible.

[0015]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a CVD (Ch) according to the present invention.
(Electric Vapor Deposition)
1 shows a schematic configuration of a film forming apparatus.

That is, the processing chamber 12 in which the semiconductor substrate 11 is accommodated is a chamber for performing a CVD film forming process on the semiconductor substrate 11, and a susceptor 12a on which the semiconductor substrate 11 is mounted, and a susceptor 12a from the back of the susceptor 12a. A heater 12b for heating the semiconductor substrate 11, and a shower head 12 for supplying a material gas onto the semiconductor substrate 11
c.

The susceptor 12a is mounted via a rotating shaft 12d.
000 rpm. By rotating the susceptor 12a, the material gas supplied from the shower head 12c is supplied to the semiconductor substrate 1
1 can be efficiently supplied on the substrate 1, so that the film forming speed can be increased.

In the processing chamber 12, along the exhaust path,
The valve 13, the pressure controller 14, and the pump 15 are connected in order. The inside of the processing chamber 12 is depressurized by the pump 15 and is controlled by the pressure controller 14 to a pressure necessary for the film forming process.

The shower head 1 in the processing chamber 12
2c, an opening adjustment valve 1 is provided along the gas flow path.
6, a container 17, a valve 18, a pressure regulating valve 19, and a gas cylinder 20 are provided.

The container 17 stores a certain amount of material gas required for one processing of one semiconductor substrate 11 supplied from the gas cylinder 20 through the pressure regulating valve 19 and the valve 18 through the valve 18. It has enough capacity. The container 17 is provided with a pressure gauge 21 for monitoring the pressure of the material gas stored therein.

The opening of the opening adjustment valve 16 provided on the gas discharge side of the container 17 is controlled by an opening adjuster 22. The opening adjuster 22 is controlled by a controller 23 connected to the pressure gauge 21.

For example, the controller 23 controls the opening adjuster 22, and the opening adjustment valve 1
6 is adjusted according to the output of the pressure gauge 21, so that the pressure change rate (dP / dt) of the material gas supplied to the processing chamber 12 in the container 17 becomes substantially constant. Is controlled as follows.

Here, it is assumed that the temperature of the semiconductor substrate 11 is 70 ° C., the number of revolutions is 5000 rpm, SiH 4 gas is supplied from the shower head 12 c at 1 slm, and H 2 gas is supplied from a nozzle (not shown) at 30 slm. Then, the deposition rate of the polysilicon film under these conditions is about 1000 nm / min. Therefore, 100
In the case of depositing polysilicon having a thickness of nm, the film formation time is about 6 seconds.

In the process of forming a 100-nm thick polysilicon film, 100 cc of SiH4 gas is required.
Assuming that the internal volume of 7 is 20 cc, this is
By storing H4 gas, it becomes 100 cc at 1 atm. That is, by using all of the 5 atm SiH4 gas stored in the container 17 having an inner volume of 20 cc,
A 100 nm-thick polysilicon film can be formed. In this case, the gas pressure in the container 17 gradually decreases from 5 atm to 0 atm. During film formation, the film formation rate usually changes depending on the flow rate of the gas, so the flow rate needs to be kept constant. This can be solved by making the pressure change rate from 5 atm to 0 atm constant.

FIG. 2 shows the relationship between the film formation time and the gas pressure when the pressure change rate is constant. As shown in this figure, the gas pressure in the container 17 is monitored by the pressure gauge 21 and the output is fed back to the control of the opening of the opening adjustment valve 16 so that the pressure of the gas in the container 17 is reduced during the film formation time. It is controlled so that it changes at a constant rate over time. Thereby, the flow rate of the material gas can be stably controlled even within the processing time as short as 6 seconds,
It is possible to keep the film forming rate constant.

Next, the procedure of the film forming process will be briefly described. Here, the content of the container 17 is assumed to be 20 cc, and 1
An example in which a 100-nm thick polysilicon film is formed using 00 cc of SiH4 gas will be described.

First, 5 atm of SiH4 gas necessary for one process is supplied from the gas cylinder 20 through the pressure regulating valve 19 and the valve 18 through the valve 18 to the container 17.
Stored inside. Further, the semiconductor substrate 11 on which the film forming process is performed
Is placed on the susceptor 12a in the processing chamber 12, and 500
Rotated at 0 rpm. Further, the semiconductor substrate 11
Is heated to 70 ° C. by the heater 12b. The processing chamber 12 is provided with a valve 1 along the exhaust path.
3. The pressure is reduced by the pressure controller 14 and the pump 15.

In this state, the opening adjustment valve 16 is opened, and the SiH4 gas stored in the container 17 is supplied to the processing chamber 12, and is supplied onto the semiconductor substrate 11 via the shower head 12c. Thereby, the semiconductor substrate 11
A polysilicon film is gradually deposited thereon.

During the film forming time, the controller 23 controls the opening degree adjuster 22 based on the output of the pressure gauge 21 so that the rate of change of the gas pressure in the container 17 becomes constant. Then, the opening of the opening adjustment valve 16 is controlled.

When the gas pressure in the container 17 is reduced to 0 atm in this way, the film forming process is completed.
Then, the semiconductor substrate 11 is replaced, and with this replacement, the inside of the container 17 is filled with an amount of SiH4 gas necessary for the next processing.

By repeating the above procedure, a 100-nm-thick polysilicon film can be formed on a single wafer with high precision. As a result, in the process of forming the polysilicon film in a short time, the variation σ in the film thickness was improved from 1.5% in the prior art to 0.5%.

As described above, a constant amount of material gas required for one processing can be supplied stably. That is, a certain amount of SiH4 gas required for one film forming process is stored in advance and supplied at a certain ratio. As a result, even if a mass flow controller (gas flow controller) is not used, SiH4
It is possible to control the gas flow rate with high accuracy. Therefore, the polysilicon film formed in a short time can be stably formed without being affected by the external environment, and the controllability of the film formation can be remarkably improved.

Moreover, since no mass flow controller is used, the cost of the apparatus can be reduced. In addition,
In the above embodiment, the case where a polysilicon film having a thickness of 100 nm is formed is described. However, the present invention is not limited to this. For example, the present invention can be applied to the formation of a film other than the polysilicon film. This can be easily achieved by changing the internal volume of the container or changing the pressure of the material gas stored in the container. It is also possible to prepare a plurality of containers having different internal volumes and switch the containers to be used according to the thickness of the film to be formed.

The present invention can be applied not only to the film forming process depending on the flow rate of the material gas (the surface reaction rate-limiting region) but also to the film forming process that does not depend much on the gas flow rate (the supply-limiting region). In this case, since the pressure change rate of the gas in the container does not need to be constant, it is not necessary to adjust the opening degree of the valve.

The present invention can be applied not only to the film forming process but also to a semiconductor manufacturing apparatus for performing an etching process, for example. Furthermore, by using together with the mass flow controller,
Higher precision control is possible.

FIG. 3 shows an example in which the CVD film forming apparatus shown in FIG. 1 is further provided with a mass flow controller (MFC). In the case of this device, the MFC 24 and the valve 25 are provided between the opening adjustment valve 16 and the shower head 12 c on the downstream side of the container 17.
Is provided. According to such a configuration, the flow rate of the material gas is controlled by the MFC 24,
By setting the total amount of the supplied material gas to a constant amount necessary for one process stored in the container 17, it is possible to perform a process with good controllability even in a short time.

It is not necessary to adjust the opening of the opening adjustment valve 16 during this processing time.
The controllability can be further enhanced by controlling the opening of the opening adjustment valve 16 so that the rate of change of the pressure of the material gas inside becomes constant. Of course, various modifications can be made without departing from the scope of the present invention.

[0038]

As described above in detail, according to the present invention, the material gas can be supplied with good controllability even in a short-time processing without being affected by the external environment, and the controllability of the processing can be improved. Gas supply apparatus for a semiconductor manufacturing apparatus and a method for supplying the same can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a CVD film forming apparatus according to one embodiment of the present invention.

FIG. 2 is a view for explaining the relationship between the film formation time and the gas pressure when the pressure change rate is constant.

FIG. 3 is a schematic configuration diagram of a CVD film forming apparatus according to another embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a film forming apparatus shown to explain a conventional technique and its problems.

[Explanation of symbols]

11: semiconductor substrate, 12: processing chamber, 12a: susceptor,
12b ... heater, 12c ... shower head, 13 ... valve, 14 ... pressure controller, 15 ... pump, 16 ... opening adjustment valve, 17 ... container, 18 ... valve, 19 ... pressure adjustment valve, 20 ... gas cylinder, 21 ... Pressure gauge, 22 ... opening regulator, 23 ... controller, 24 ... mass flow controller (MFC).

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/205 C23C 16/44 C23F 4/00 H01L 21/3065

Claims (4)

(57) [Claims] 1. A gas supply device for supplying a material gas for processing to a processing chamber of a semiconductor manufacturing apparatus, comprising: a container for storing a constant amount of the material gas required for processing at least one semiconductor substrate; A pressure gauge for measuring a pressure of the material gas of the container, and adjusts an opening degree of a valve provided on a gas discharge portion side of the container.
Is supplied from the container to the processing chamber.
The rate of change in pressure of the material gas in the vessel is substantially constant
A gas supply device for a semiconductor manufacturing apparatus, characterized in that the gas supply device is controlled to be as follows. 2. A gas flow controller is provided downstream of the valve, and the material gas in the container is supplied to the processing chamber via the gas flow controller. 2. The gas supply device for a semiconductor manufacturing apparatus according to 1 . 3. A method according to claim 1, wherein a predetermined amount of material gas required for processing at least one semiconductor substrate is stored in the container, and the pressure of the material gas in the container is measured by a pressure gauge and stored in the container. The material gas is transferred to the gas of the container.
To adjust the opening of the valve provided on the
Thus, the pressure change rate in the container is substantially constant.
While controlling the gas supply method of a semiconductor manufacturing apparatus and supplying to the processing chamber in which the semiconductor substrate is housed. 4. The semiconductor manufacturing apparatus according to claim 3 , wherein the material gas passing through the valve is supplied to the processing chamber via a gas flow controller provided on a downstream side thereof. Gas supply method.