JP2003197613A - Substrate treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a supply amount of a liquid raw material from fluctuating due to a mixture of gas. <P>SOLUTION: An MOCVD apparatus 10 comprises a tank 32 for storing the liquid raw material 31, a vaporizer 21 for vaporizing the raw material, a liquid raw material supply duct 35 for supplying the material from the tank 32 to the vaporizer 21, and a gas supply duct 20 for supplying raw material gas 51 vaporized from the material from the vaporizer 21 to a treating chamber 11 for forming a wafer 11. In the apparatus 10, the tank 32 is disposed at a higher position than the vaporizer 21, and the duct 35 is so constituted as a liquid raw material inlet 36 disposed at a highest position. Since bubbles generated in the liquid raw material supply duct is discharged from the inlet at the top of the supply duct into the tank, it can prevent the supply amount of the material from fluctuating due to the mixture of the bubbles, and the reproducibility of the film thickness of the MOCVD apparatus is improved. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate processing apparatus, and more particularly to a substrate processing apparatus in which a liquid material is used, and for example, MOCVD (Metal Organic Chemical Vapor Depos
ition) technology effective for use in equipment.

[0002]

2. Description of the Related Art DRAM (Dynamic Random Access Memo)
In order to form a high dielectric thin film as a material of the electrostatic capacity portion (insulating film) of the capacitor (capacitor) of rry), Ta
₂ O ₅ (tantalum pentoxide) has been used. Ta
_{Since 2} O ₅ has a high dielectric constant, it is suitable for obtaining a large capacitance in a fine area. From the viewpoint of productivity, film quality, etc., in the method of manufacturing a DRAM, it is required that Ta ₂ O ₅ be formed into a film by a MOCVD device.

MOCVD used to deposit Ta ₂ O ₅
The apparatus includes a processing chamber for processing a semiconductor wafer (hereinafter referred to as a wafer) in which a DRAM, which is an example of a semiconductor integrated circuit, is processed, a source gas supply pipe having one end connected to the processing chamber, and a source gas supply. A vaporizer connected to the other end of the pipe for vaporizing the liquid raw material, and a liquid raw material supply device for supplying the liquid raw material to the vaporizer are provided, and the liquid raw material is supplied from the liquid raw material supply device to the vaporizer, This liquid raw material is vaporized in a vaporizer, and the vaporized raw material gas is supplied to the processing chamber to form a Ta ₂ O ₅ film on the wafer in the processing chamber.

[0004]

However, the MOCVD apparatus using the liquid raw material has a problem that it is difficult to secure the reproducibility of the film thickness as compared with the CVD apparatus using the gas raw material. One of the causes is said to be because it is more difficult to control the supply amount of liquid than gas. The reason why it is difficult to control the supply amount is the inert gas (nitrogen gas, helium gas, etc.) that is presumed to be dissolved in the liquid raw material.
It is considered that this is because it is not possible to control the amount of the constant. That is, the pressure of the liquid raw material becomes lower as the liquid raw material approaches the processing chamber (vaporizer), and the dissolved inert gas becomes bubbles to come out inside the liquid raw material. Therefore, the liquid raw material is supplied depending on the generated amount of the gas. This is because the amount changes.

An object of the present invention is to provide a substrate processing apparatus capable of preventing fluctuations in the supply amount of liquid raw material due to gas mixture.

[0006]

A first means for solving the problems is a tank for storing a liquid raw material, a vaporizer for vaporizing the liquid raw material, and the liquid raw material from the tank to the vaporizer. A substrate processing apparatus comprising: a liquid raw material supply pipe for supplying; and a gas supply pipe for supplying a gas obtained by vaporizing the liquid raw material from the vaporizer to a processing chamber for processing a substrate, wherein the tank is the vaporizer. It is characterized in that the liquid raw material supply pipe is arranged at a higher position than the above, and the liquid raw material supply pipe is configured so that the intake of the liquid raw material is at the highest position.

According to the first means, since the inlet of the liquid raw material is set at the highest position, the gas generated in the liquid raw material supply pipe is supplied by the liquid raw material due to the specific gravity relationship between the liquid and the gas. Through the liquid raw material filled in the pipe, the liquid raw material is discharged from the intake port to the inside of the tank. Therefore, since the gas in the liquid raw material can be constantly discharged, it is possible to prevent the supply amount of the liquid raw material from fluctuating due to mixing of the gas.

A second means for solving the problem is a tank for storing a liquid raw material, a vaporizer for vaporizing the liquid raw material, and a liquid raw material supply pipe for supplying the liquid raw material from the tank to the vaporizer. And a gas supply pipe for supplying a gas obtained by vaporizing the liquid raw material from the vaporizer to a processing chamber for processing a substrate, wherein the liquid raw material is supplied to the liquid raw material supply pipe. It is characterized in that a buffer part for storing the gas is provided.

According to the second means, the gas generated in the liquid raw material supply pipe is discharged into the buffer portion through the liquid raw material filled in the liquid raw material supply pipe due to the specific gravity relationship between the liquid and the gas. Will be. Therefore, since the gas in the liquid raw material can be constantly discharged, it is possible to prevent the supply amount of the liquid raw material from fluctuating due to mixing of the gas.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

In this embodiment, as shown in FIG. 1, the substrate processing apparatus according to the present invention is configured as a MOCVD apparatus, and this MOCVD apparatus is a DRAM.
₂ O of the capacitance part of the capacitor in the manufacturing method of
₅ Used in the process of forming a film (hereinafter referred to as the capacitor forming process).

The MOCVD apparatus 10 shown in FIG. 1 includes a housing 12 in which a processing chamber 11 is formed.
Is configured as a single-wafer cold wall type low pressure CVD apparatus. An exhaust pipe 13 for exhausting the processing chamber 11 is connected to a lower portion of the housing 12, and an oxygen gas supply pipe for supplying oxygen (O ₂ ) gas to the processing chamber 11 is connected to an upper portion of the housing 12. 14 is connected. A support shaft 15 is rotatably and vertically movable through the bottom wall of the housing 12,
The support shaft 15 is configured to be rotated and driven up and down by a driving device (not shown). A susceptor 16 for holding the wafer 1, which is a substrate to be processed, is disposed on the upper surface of the support shaft 15 in the processing chamber 11. Support shaft 15
A heater 17 is installed inside the upper end of the so as to uniformly heat the wafer 1 held by the susceptor 16.
A wafer loading / unloading port 18 for loading / unloading the wafer 1 is provided in a part of the side wall of the housing 12, and the wafer loading / unloading port 18 is opened and closed by a gate 19.

On the ceiling wall of the housing 12, the source gas is supplied to the processing chamber 1.
1, one end of a raw material gas supply pipe 20 is inserted, and the other end of the raw material gas supply pipe 20 is connected to a vaporizer 21 for vaporizing a liquid raw material. At the insertion end of the raw material gas supply pipe 20, a blowing head 22 that blows the raw material gas in a shower shape is installed. The other end of a carrier gas supply pipe 24, one end of which is connected to a carrier gas supply source 23 for supplying a carrier gas, is connected between the vaporizer 21 and a liquid flow rate control device 37 described later. In the middle of 24, a variable flow control valve 25
Is installed. The liquid raw material supply device 3 is provided in the vaporizer 21.
0 is connected. Note that, in FIG. 1, for convenience, the liquid flow rate control device 37 and the vaporizer 21 are arranged at a predetermined distance by a pipe, but in reality, the liquid flow rate control device 37 and the vaporizer 21 are extremely close to each other. Are arranged.

The liquid raw material supply device 30 is provided with a tank 32 for storing the liquid raw material 31, and the tank 32 is a carburetor 2.
It is arranged at a position higher than 1 in terms of gravity. Tank 3
An injection port 33 closed by a cap 34 is opened in the center of the ceiling wall of No. 2. One end of a liquid raw material supply pipe 35 for supplying the liquid raw material 31 to the vaporizer 21 is connected to the central portion of the bottom wall of the tank 32, and the liquid raw material supply pipe 35 is a tank serving as an inlet 36 for the liquid raw material. 32
The connection port to and is configured so as not to have the highest position (top) of the liquid raw material supply pipe 35, that is, the supply path against gravity. The other end of the liquid raw material supply pipe 35 is connected to the vaporizer 21, and a liquid flow rate control device 37 including a liquid flow rate control valve, a liquid flow meter, an on-off valve, etc. is provided in the middle of the liquid raw material supply pipe 35. It is installed.

On the ceiling wall of the tank 32, a delivery gas supply pipe 43 for delivering a delivery gas 42 for delivering the liquid raw material.
Is connected to one end, and the other end of the delivery gas supply pipe 43 is connected to a delivery gas supply source 41 which supplies an inert gas such as nitrogen gas as the delivery gas 42. An end of the delivery gas supply pipe 43, which is inserted into the tank 32, is opened in an upper space 32 a of the liquid raw material 31 in the tank 32. A stop valve 44 is provided in the delivery gas supply pipe 43.

Next, the MOCVD apparatus 1 having the above configuration
The capacitor forming process in the method of manufacturing the DRAM in which 0 is used will be described.

In the present embodiment, the capacitance portion of the capacitor is formed of Ta ₂ O ₅ film. Therefore, the wafer 1 carried into the processing chamber 11 of the MOCVD apparatus 10 has a predetermined pattern formed before the formation of the capacitance portion of the capacitor. Then, Ta (OC ₂ H ₅ ) ₅ (penta-ethoxy-tantalum; hereinafter referred to as PETa) is stored as a liquid raw material 31 in the tank 32 of the liquid raw material supply device 30.

The wafer 1 on which a predetermined pattern is formed is held by a handling device (not shown), and the processing chamber 11 is transferred from the wafer loading / unloading port 18 with the gate 19 opened.
And is delivered to the susceptor 16. The wafer 1 transferred to the susceptor 16 has a heater 17
Is heated to a predetermined temperature (430-480 ° C) by
The support shaft 15 raises and rotates. Processing room 11
Is exhausted to a predetermined pressure (20 to 40 Pa) by a vacuum pump (not shown) connected to the exhaust pipe 13. When the processing chamber 11 stabilizes at a predetermined pressure, oxygen gas 50 is supplied from the oxygen gas supply pipe 14 as indicated by the double-dashed line arrow in FIG.

When the stop valve 44 of the delivery gas supply pipe 43 of the liquid raw material supply device 30 is opened and the delivery gas 42 is supplied from the delivery gas supply source 41 to the upper space 32a of the tank 32, the delivery gas 42 is transferred to the tank. In order to push down the liquid surface of the liquid raw material 31 stored in 32, the liquid raw material 31 is sent out to the liquid raw material supply pipe 35. Then, under the control of the liquid flow rate control device 37 of the liquid raw material supply pipe 35, PETa as the liquid raw material 31 is supplied to the vaporizer 21 through the liquid raw material supply pipe 35.

By the way, nitrogen gas, helium gas, etc. are dissolved as impurities in the liquid of PETa which is the liquid raw material 31, and the liquid raw material 31 is the gas from these gases.
When the pressure of the liquid raw material 31 decreases as it gets closer to the (vaporizer 21), the liquid raw material 31 cannot be dissolved in the liquid, so that the liquid raw material 3 becomes bubbles 53 as shown in FIG.
It comes out in the liquid of 1. When the bubbles 53 flow into the liquid flow rate control device 37, the flow rate control of the liquid raw material 31 by the liquid flow rate control device 37 is affected by the content of the bubbles 53. Therefore, the vaporizer of the liquid raw material 31 depends on the generation amount of the bubbles 53. The supply amount to 21 will fluctuate.

However, in the present embodiment, since the liquid raw material supply pipe 35 is set at the highest position of the intake port 36 of the liquid raw material 31, the specific gravity generated inside the liquid raw material supply pipe 35 is higher than that of the liquid. A much smaller bubble 5
3 rises in the liquid raw material 31 filled in the liquid raw material supply pipe 35, and is discharged from the intake port 36 to the upper space 32a of the tank 32. Therefore,
Since it is possible to prevent the bubbles 53 from flowing into the liquid flow rate control device 37, the flow rate control of the liquid raw material 31 by the liquid flow rate control device 37 is not affected by the generation amount of the bubbles 53, and the liquid flow rate control device 37. Can supply the liquid raw material 31 with a preset flow rate to the vaporizer 21.

As described above, PETa, which is the liquid raw material 31 properly controlled to the preset flow rate by the liquid flow rate controller 37, is supplied to the vaporizer 21 and atomized into fine particles, and at the same time, the vaporizer 21. It is effectively vaporized by being heated by the cartridge heater built in the, and becomes a raw material gas. On the other hand, an inert gas such as N ₂ (nitrogen) gas is introduced into the vaporizer 21 from a carrier gas supply source 23 through a carrier gas supply pipe 24 as a carrier gas.

As shown in FIG. 1, the raw material gas 51 formed by vaporizing PETa in the vaporizer 21 is mixed with the carrier gas 52, flows from the vaporizer 21 through the raw material gas supply pipe 20, It blows out like a shower from the blowing head 22 to the processing chamber 11. PET blown into the processing chamber 11
Since the source gas 51, which is the vaporized gas of a, is sufficiently vaporized, it becomes Ta ₂ O ₅ on the wafer 1 and becomes susceptor 16 a.
Is deposited on the heated and held wafer 1 by a thermal CVD reaction. By this deposition, a Ta ₂ O ₅ film is formed on the surface of the wafer 1. The conditions for forming the Ta ₂ O ₅ film are as follows. Film formation temperature is 352 to 520
C, pressure 15-300 Pa, carrier gas flow rate 0.1-1 SLM (standard liters per minute),
The pumping gas pressure is 0.05 to 0.3 MPa, and the flow rate of the raw material gas is 0.01 to 0.5 ccm (cubic centimeter per minute).

After a preset time has elapsed for the Ta ₂ O ₅ film forming process, the on / off valve of the liquid flow rate control device 37 of the liquid raw material supply pipe 35 of the vaporizer 21 and the variable flow rate control valve of the carrier gas supply pipe 24. By closing 25, the supply of PETa as the liquid raw material 31 and the carrier gas 52 is stopped.

The wafer 1 on which the Ta ₂ O ₅ film is formed as described above is unloaded from the processing chamber 11 by the handling device. After that, the Ta ₂ O ₅ film is formed on the wafer 1 by repeating the above-described work.

According to the above embodiment, the following effects can be obtained.

1) The bubbles (gas) generated inside the liquid raw material supply pipe are discharged from the inlet to the space above the tank by setting the inlet of the liquid raw material supply pipe to the highest position. Therefore, it is possible to prevent bubbles from flowing into the liquid flow rate control device.

2) By preventing the bubbles generated in the liquid raw material of the liquid raw material supply pipe from flowing into the liquid flow rate control device, the flow rate control of the liquid raw material by the liquid flow rate control device is influenced by the amount of bubbles generated. Since this can be prevented, the liquid flow rate control device can appropriately supply the liquid raw material at a preset flow rate to the vaporizer.

3) By properly supplying a preset flow rate of liquid raw material to the vaporizer, the vaporizer can supply a preset amount of raw material gas to the processing chamber,
It is possible to secure film formation with good reproducibility of film thickness in the MOCVD apparatus.

FIG. 2 shows a second embodiment M of the present invention.
It is a schematic diagram which shows an OCVD apparatus.

The present embodiment differs from the above-mentioned embodiments in that the tank 32A is arranged at an arbitrary height, and one end of the liquid raw material supply pipe 35A is inserted into the ceiling wall of the tank 32A so that the intake port 36A is provided. Is opened in the liquid of the liquid raw material 31, and a buffer pipe 38 as a buffer portion for temporarily storing bubbles (gas) generated in the liquid of the liquid raw material 31 is connected in the middle of the liquid raw material supply pipe 35A. That is the point.

According to the present embodiment, the bubbles 53 generated in the liquid of the liquid raw material 31 are removed from the liquid raw material supply pipe 35A.
Since it can be collected by the buffer pipe 38 connected midway, it is possible to prevent the bubbles 53 from flowing into the liquid flow rate control device 37, and it is possible to obtain the same effect as that of the above-described embodiment. Further, according to the present embodiment, the tank 32A can be arranged at an arbitrary height, so that the degree of freedom in the layout of the MOCVD device 10 can be increased. Since the pressure becomes lower and the bubbles are more likely to be generated as the position is closer to the processing chamber 11, the installation position of the buffer pipe 38 is preferably as close to the processing chamber 11 as possible. That is, the vicinity of the vaporizer 21 is preferable. Further, the buffer pipe 38 may be provided at a plurality of places. For example, it may be provided at a plurality of locations between the tank 32A and the liquid flow rate control device 37. Also, the buffer tube 3
A drain pipe for removing the collected air bubbles may be provided at 8.

FIG. 3 is a graph showing the effect of improving the reproducibility of the film thickness, in which the vertical axis represents the film thickness and the horizontal axis represents the number of processed wafers. Line A shows the case of the conventional example,
A polygonal line B shows the case of the first embodiment of the present invention, and a polygonal line C shows the case of the second embodiment of the present invention.

According to FIG. 3, the polygonal line A showing the conventional example has extremely poor reproducibility of the film thickness, whereas the polygonal line B showing the first embodiment and the polygonal line C showing the second embodiment. It is understood that in (1), the reproducibility of the film thickness is improved very well.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

For example, not only PETa is used as the liquid raw material, but also Nb (OC ₂ H ₅ ) ₅ (pentaethoxyniobium) for forming a film of Nb ₂ O ₅ (niobium pentoxide), TiOx Ti (OC ₃ H ₇ ) ₄ (tetra isopropyl titanium) for forming (titanium oxide) and Zr (OC ₄ H ₉ ) ₄ (tetra butoxy for forming ZrO ₂ (zirconium dioxide). Zirconium), Hf (OC ₄ H ₉ ) ₄ (tetra-butoxy-hafnium) for forming HfO ₂ (hafnium dioxide) may be used.

Further, the case where the present invention is applied to the capacitor forming step in the DRAM manufacturing method has been described, but the present invention is not limited to this, and an FRAM (ferro electric
PZT (PbZrT) for forming a capacitor of RAM)
iO ₃ ) or a metal film of iridium, ruthenium, copper or the like, and a film forming technique of those metal oxide films can also be applied.

The substrate processing apparatus is not limited to the single-wafer cold wall type CVD apparatus, but may be a single-wafer hot wall type CVD apparatus or a single-wafer wall CV.
It may be configured as a D device or the like.

[0039]

As described above, according to the present invention,
Since it is possible to prevent the supply amount of the liquid raw material from fluctuating due to the gas mixture, it is possible to stabilize the quality of the treatment.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a MOCVD apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a MOCVD device according to a second embodiment of the present invention.

FIG. 3 is a graph showing the effect of improving film thickness reproducibility.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wafer (substrate), 10 ... MOCVD apparatus (substrate processing apparatus), 11 ... Processing chamber, 12 ... Housing, 13 ... Exhaust pipe, 1
4 ... Oxygen gas supply pipe, 15 ... Support shaft, 16 ... Susceptor,
17 ... Heater, 18 ... Wafer loading / unloading port, 19 ... Gate, 20 ... Raw material gas supply pipe, 21 ... Vaporizer, 22 ... Blowing head, 23 ... Carrier gas supply source, 24 ... Carrier gas supply pipe, 25 ... Variable flow rate Control valve, 30 ... Liquid raw material supply device, 31 ... Liquid raw material, 32, 32A ... Tank, 3
2a ... upper space, 33 ... injection port, 34 ... cap, 3
5, 35A ... Liquid raw material supply pipe, 36, 36A ... Intake port, 37 ... Liquid flow rate control device, 38 ... Buffer pipe (buffer section), 41 ... Delivery gas supply source, 42 ... Delivery gas, 4
3 ... Delivery gas supply piping, 44 ... Stop valve, 50 ... Oxygen gas, 51 ... Raw material gas, 52 ... Carrier gas, 53 ... Bubbles.

Continued front page    F-term (reference) 4K030 AA11 BA17 BA42 CA04 CA12                       EA01 EA03                 5F045 AA04 AB31 AC07 AD07 AD08                       AD09 AE19 AE21 BB01 DC63                       DP03 EC08 EE02 EE03 EE04                       EF05

Claims (2)

[Claims] 1. A tank for storing a liquid raw material, a vaporizer for vaporizing the liquid raw material, a liquid raw material supply pipe for supplying the liquid raw material from the tank to the vaporizer, and a gas for vaporizing the liquid raw material. A substrate processing apparatus comprising: a gas supply pipe for supplying a processing chamber for processing a substrate from the vaporizer, wherein the tank is arranged at a position higher than the vaporizer, and the liquid raw material supply pipe is A substrate processing apparatus, characterized in that the inlet of the liquid raw material is arranged at the highest position. 2. A tank for storing a liquid raw material, a vaporizer for vaporizing the liquid raw material, a liquid raw material supply pipe for supplying the liquid raw material from the tank to the vaporizer, and a gas for vaporizing the liquid raw material. A substrate processing apparatus comprising: a gas supply pipe for supplying a gas from the vaporizer to a processing chamber for processing a substrate, wherein the liquid raw material supply pipe is provided with a buffer section for storing gas generated in the liquid raw material. A substrate processing apparatus characterized by being provided.