JP3326538B2 - Cold wall forming film processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cold wall
The present invention relates to a formed film processing apparatus.

[0002]

2. Description of the Related Art A CVD apparatus used in a film forming process of a semiconductor integrated circuit has a hot-wall type in which an entire processing vessel is placed in an electric furnace to heat a semiconductor wafer, and a processing vessel itself is at room temperature (room temperature). It is divided into a cold wall type in which only the semiconductor wafer is heated as it is. Generally, the hot wall type is used for batch processing for forming a large number of semiconductor wafers at a time, whereas the cold wall type is used for single wafer processing for forming semiconductor wafers one by one.

In a cold-wall type CVD apparatus, a semiconductor wafer is set on a susceptor (substrate mounting table), and light is directly applied to the wafer from outside without heating the semiconductor wafer via a susceptor by a suitable heater. While applying and heating, a predetermined gas is supplied to the surface of the semiconductor wafer, and a decomposition product or a reaction product of the gas is deposited on the wafer. When a film is formed on the semiconductor wafer in this manner, decomposition products or reaction products of the reactive gas are deposited on the surfaces of the susceptor, wafer holding means, and the like around the semiconductor wafer, and the film adheres. Such a coating may also adhere to the inner wall surface of the processing container.

Conventionally, as a method of cleaning the inside of a cold-wall type CVD apparatus, a cleaning gas containing NF3 is supplied into the apparatus, and the film adhering to the susceptor and the wafer holding means as described above is etched by the cleaning gas. There is known a method of removing. In this cleaning method, plasma is used because the decomposability of NF3 itself is not good. That is, an electrode plate is arranged at a position facing the susceptor in the processing vessel, and a high-frequency voltage is applied between the susceptor and the electrode plate to generate plasma therein, and the plasma excites NF3 to an active state. Like that.

[0005] In the cold wall type processing apparatus,
A susceptor (substrate mounting table) for mounting and supporting the substrate is required
Jig, and the most unwanted coating adheres
It is also an easy member. However, the NF3
Plasma cleaning method generates plasma
Not only requires a high-frequency power supply and electrode plates for
A susceptor site (particularly
It is difficult to remove the coating on the outer peripheral edge of the
Low cleaning speed (etching rate for film removal)
There was also a problem.

[0006] From the viewpoint of exhaust gas control, it is customary to attach an expensive removal device for decomposing and removing harmful and dangerous gas components from exhaust gas in a CVD apparatus, but NF3 is decomposed. Since it is a difficult gas, a common removal device cannot be used with other exhaust gas such as a reaction gas, and a dedicated removal device is required separately. Therefore, two removal devices have to be installed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has an advantage in that a large amount of an undesired film adheres most efficiently in a cold-wall-type processing vessel at a large cleaning speed from a substrate mounting table. and to provide a cold-wall type thin film deposition apparatus which is adapted to remove the safety coating.

[0008]

To achieve the above object, according to the Invention The cold-wall type thin film deposition apparatus of the present invention, a vacuum can be treated vessel, to support by placing the target substrate in the processing chamber a substrate holding base, and heating means for the substrate to be treated is heated through the substrate holding table in the film forming process, a predetermined processing gas for film formation in the film formation process prior to
A processing gas supply means for supplying the processing container via the perforated plate facing the substrate mounting table into the processing container; and a cleaning gas supply for supplying a cleaning gas containing ClF3 to the processing container via the perforated plate in the cleaning step. means a film forming process and a cleaning vacuum <br/> exhaust means for exhausting gas in the processing chamber while maintaining said processing chamber at a predetermined vacuum degree through a predetermined exhaust path in each step of the process In the cleaning step, the heating operation of the heating means with respect to the substrate mounting table is turned on, and the film adhered to the substrate mounting table in a state where the substrate mounting table is heated within the range of its corrosion resistance temperature. It was configured to be removed.

[0009]

[0010]

[Action] In cold-wall type thin film deposition apparatus of the present invention, a predetermined film forming process step is performed several times, at the time the undesired coating of the film forming material to the substrate installation platform in the processing container is attached, A cleaning step may be performed. In this cleaning step, the heating means heats the substrate mounting table on which the substrate to be processed is not mounted, and the cleaning gas containing ClF3 is reduced there by the cleaning gas supply means.
From the perforated plate evenly toward the substrate
Be paid. The supplied ClF3 gas easily reacts with the coating on the substrate mounting table even without plasma. That is, C
When a part of the 1F3 gas reacts and generates reaction heat, the reaction heat activates the nearby ClF3 gas and reacts, and more ClF3 gas is activated and reacted by the reaction heat. Spontaneously develop etching. The spontaneous etching with the ClF3 gas is possible at room temperature, but the present inventors have found that the higher the cleaning temperature, the higher the etching rate for removing the film. At the same time, it has been found that if the temperature of the substrate mounting table heated by the heating means exceeds its corrosion resistance temperature, particles may be generated from the substrate mounting table. From this viewpoint, in the present invention, an undesired film of a film- forming material adhering to a substrate mounting table is removed by performing spontaneous etching with a ClF3 gas while heating the substrate mounting table within the range of its corrosion resistance temperature. It can be efficiently and safely removed at a large cleaning speed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a cold wall type single wafer type CVD apparatus will be described below with reference to the accompanying drawings.

In FIG. 1, a processing vessel 10 of this CVD apparatus is a cylindrical chamber made of, for example, aluminum, and a susceptor (substrate mounting table) 12 is provided at a central portion thereof. When the film forming process is performed, the semiconductor wafer 14 is mounted on the susceptor 12 as shown by a dotted line. A gate valve 16 is provided on one side wall of the processing container 10, and the semiconductor wafer 14 is taken in and out through the gate valve 16.

A perforated plate 18 for uniformly supplying gas is mounted above the susceptor 12, and a gas discharge portion 20a of a gas introduction pipe 20 is vertically inserted into the container from the back (upper portion) of the perforated plate 18. Have been. In this gas introduction pipe 20,
A reaction gas supply system 22 and a cleaning gas supply system 24 are connected, and these are switched by valves 26 and 28.
Done by

The cleaning gas supply system 24 is provided with a ClF3 gas supply unit 30 for supplying ClF3 as an etching gas and an N2 gas supply unit 32 for supplying N2 gas as a diluting carrier gas. Reference numerals 30 and 32 denote gas flow controllers (MFCs) 34 and 32, respectively.
36 and the gas introduction pipe 20 via valves 38, 40, etc.
Connected to. By adjusting the supply flow rates of the ClF3 gas and the N2 gas by the gas flow controllers 34 and 36, a cleaning gas in which ClF3 is diluted to a predetermined concentration is supplied to the gas introduction pipe 20.

At the lower part of the processing container 10, the container bottom 1
A plurality of exhaust ports 42 are provided in Oa. The reaction product gas generated in the processing container 10 and the surplus reaction gas or cleaning gas are discharged from these exhaust ports 42 through the exhaust pipe 44 to the vacuum pump 46 side. It is preferable to use an oil-free dry pump as the vacuum pump 46. This is because the use of a wet pump for using ClF3 as a cleaning gas may cause deterioration of the pump oil and deterioration of the pump itself due to chlorine or fluorine mixed in the oil.

The discharge system downstream of the vacuum pump 46 is provided with a removing device 48 for removing harmful and dangerous gas components from the exhaust gas of the reaction gas or the cleaning gas discharged from the pump. The removing device 48 contains a tube 50 containing a chemical for absorbing or decomposing harmful or dangerous gas components.

A quartz window 52 is attached to the bottom of the container below the susceptor 12, and a heating halogen lamp 54 is provided below the quartz window 52. During the film forming process, the light from the halogen lamp 54 is transmitted to the quartz window 52.
Irradiates the back surface of the susceptor 12 through the susceptor 12, and the light energy heats the susceptor 12 to, for example, 650 to 700 ° C., and the semiconductor wafer 14 is heated to about 500 to 550 ° C. through the heated susceptor 12, for example. It is supposed to be.

Next, the step of forming a tungsten-based film in the CVD apparatus and the step of cleaning the CVD apparatus will be described.

First, the step of forming a tungsten-based film will be described. The semiconductor wafer 14 subjected to the film forming process
The wafer is loaded onto the susceptor 12 by a wafer transfer mechanism (not shown) such as a hand arm via the gate valve 16. Next, as reaction gases, for example, WF6 (tungsten hexafluoride) and SiH2 C12 (dichlorosilane) are introduced into the processing vessel 10 from the reaction gas supply system 22 through the gas introduction pipe 20 at predetermined flow rates. The introduced reaction gas is blown onto the semiconductor wafer 14 through the perforated plate 18 so that the semiconductor wafer 14
Is formed on the surface of WSi (tungsten silicide). When WF6 and H2 are used as another reaction gas, a W (tungsten) film is formed on the surface of the semiconductor wafer 14.

In this film forming step, the semiconductor wafer 14
Is heated by the heating lamp 54 via the susceptor 12, but the processing container 10 itself is kept at room temperature (room temperature). In addition, most of the decomposition products or reaction products of the reaction gas are deposited on the surface of the semiconductor wafer 14, but a part thereof adheres to the outer peripheral edge of the susceptor 12 and a wafer holding member (not shown), and It adheres to the inner wall surface of 10 slightly. When the film forming process is completed, the semiconductor wafer 1
4 is unloaded from the susceptor 12 by the wafer transfer mechanism. During the unloading or loading, the semiconductor wafer 14 or the susceptor 1
2. The coating may be peeled off from the wafer holding member or the like.
a and the like.

When the above-described film forming process is performed a predetermined number of times, the film forming process is temporarily stopped, the reaction gas supply system 22 and the heating lamp 54 are turned off, and the processing vessel 1
The cleaning according to the present embodiment is performed at a normal temperature in a state where the semiconductor wafer 14 is not in the area 0. Prior to this cleaning, purging with H2 gas or N2 gas or the like is performed to remove the reaction gas from the processing container 10.

In the cleaning according to this embodiment,
As described above, ClF3 is supplied from the cleaning gas supply system 24.
A cleaning gas obtained by diluting the gas to a predetermined concentration with N2 gas is introduced into the processing vessel 10 through the gas introduction pipe 20, and the introduced cleaning gas is supplied from the perforated plate 18 to the susceptor 12 and other parts of the apparatus. .

The ClF3 gas is a chemically active gas, and reacts well with a film, particularly a tungsten-based film, even without plasma. Therefore, by controlling the supply flow rate so that the cleaning gas fills the inside of the processing vessel 10, the ClF3 gas spreads to every corner in the processing vessel 10, and the WSi film or W film adhering to each part becomes C
The etching is effectively performed only by receiving the supply of the 1F3 gas.

Thus, the coating on the bottom surface 10a of the container, which is difficult to remove by the conventional NF3 plasma cleaning method, can be easily removed by the cleaning method of this embodiment. Therefore, there is no need for manual cleaning, which is troublesome for an operator. In addition, Cl
When the F3 gas passes through the exhaust port 42 and the exhaust pipe 44, the film adhering thereto is also etched and removed.

Since the ClF3 gas has a good decomposability and is easily dissolved in an alkali solution or the like, the exhaust gas can be treated by the common removing device 48 similarly to the exhaust gas of the reaction gas. Therefore, no special cleaning device is required.

FIGS. 2 to 5 are graphs showing the etching effect of the cleaning method of this embodiment. The data shown in the figure shows that a semiconductor wafer having a W film formed on its surface is placed on the susceptor 12 as a test material, and the cleaning film containing the ClF3 gas is supplied under various conditions. This was obtained in an experimental example in which the etching rate was measured.

First, the graph of FIG. 2 shows the characteristics of the etching rate when the gas pressure is changed while the flow rates of the ClF3 gas and the N2 gas in the cleaning gas are kept constant at 500 sccm at room temperature. As shown in FIG. 2, as the gas pressure is increased, the reaction between the ClF3 gas and the W film is accelerated, and the etching rate is increased.
It can be seen that an etching rate of 000 angstroms / min can be obtained.

The graph in FIG. 3 shows the characteristics of the etching rate when the flow rate of the ClF3 gas is changed while keeping the flow rate of the N2 gas constant at 1500 sccm and the pressure at 10 Toor at room temperature. As can be seen from FIG. 3, as the flow rate of the ClF3 gas is increased, the supply rate of the ClF3 gas is increased and the etching rate is increased, and
It can be seen that an etching rate of about 3000 to 6000 angstroms / min can be obtained for a ClF3 gas flow rate of m.

The graph in FIG. 4 shows the characteristics of the etching rate when the flow rate of ClF3 gas is kept constant at 500 sccm and the pressure is kept constant at 10 Toor at room temperature, and the flow rate of N2 gas is changed. As can be seen from FIG. 4, as the flow rate of the N2 gas is increased, the ClF3 gas is diluted and the etching rate is reduced, and the flow rate of the N2 gas is 500 to 5000 sccm.
It can be seen that an etching rate of min can be obtained.

The graph of FIG. 5 shows that the pressure is 10 To
This shows the characteristics of the etching rate when the flow rate ratio between ClF3 gas and N2 gas is kept constant (1: 3) while the total flow rate is kept at rr. From this figure, it can be seen that, as the flow rate of the cleaning gas is increased, the supply amount of the ClF3 gas is increased, and the etching rate is increased.
About 360 for a flow rate of 3000 ClF3 / N2 gas
It can be seen that an etching rate of 0 to 4800 angstroms / min can be obtained.

As described above, according to the cleaning method of this embodiment, even at room temperature, the etching rate of 3000 Å / min or more can be easily achieved by appropriately selecting the conditions such as the flow rate of the gas, the pressure, and the concentration of the ClF 3 gas. Can be obtained. Experiments have confirmed that a similar etching rate can be obtained with the WSi coating. In this respect, the etching rate obtained by the conventional plasma-type cleaning method using NF3 gas is at most about 2,000 angstroms / min, so that the cleaning efficiency is as good as that of the conventional method.

Next, a second embodiment of the present invention will be described. In the second embodiment, a susceptor 14, a wafer holding member (not shown), a processing vessel 10 in a cold wall type processing apparatus, for example, a processing apparatus as shown in FIG.
In a state where a heatable portion such as an inner wall of the container is maintained at a high temperature within a range of a corrosion resistance temperature to ClF3, a cleaning gas containing ClF3 is supplied thereto, and each portion of the container 10, etc. Cleaning is performed.

FIG. 6 shows the respective corrosion resistance temperatures of ClF3 of various materials available for the heatable portion in the cold wall type processing apparatus. When these materials are used for heatable portions such as a susceptor, a wafer holding member, and a processing container, the higher the temperature, the higher the cleaning speed. However, when the temperature exceeds the range of the corrosion resistance temperature , particles are generated from the member itself, which is not good.
Therefore, even if the temperature is high, the corrosion resistance temperature of each part
It is desirable to keep it below the upper limit value of .

FIG. 7 shows that the heatable portion in the cold wall type processing apparatus is composed of silicon carbide (SiC), the degree of vacuum (10 Torr) in the container, and the cleaning gas (Cl
F3 / N2) flow rate (100/2000 sccm), cleaning gas supply method (simultaneous supply of ClF3 / N2),
The characteristics of the etching rate when the conditions of the cleaning time (20 seconds) are fixed and the cleaning temperature is changed are shown. As shown in FIG. 7, as the cleaning temperature is increased, the etching rate is increased, and at a high temperature around 200 ° C., about 3200 angstroms / mi.
It can be seen that an etching rate of n can be obtained.

As the heating means, a heating means for heat treatment such as the halogen lamp 54 in FIG. 1 may be used .
No. Further, a heating means such as a nichrome wire for cleaning may be embedded inside the wall or the like of the processing container 10.

In the above-described embodiment, the cleaning is performed by removing the W film or the WSi film. However, the present invention is applicable not only to the tungsten-based film but also to an undesired film of another film forming material. Cleaning method can be used. Further, the cold wall type processing apparatus in the above-described embodiment is a single wafer type CVD apparatus. However, the cleaning method of the present invention is not limited to such a film forming processing apparatus, but may be another type such as a sputtering apparatus. It can also be used for a cold wall forming film processing apparatus .

[0037]

As described in the foregoing, in accordance with a cold-wall type thin film deposition apparatus of the present invention, to remove the undesired coating of the film forming material from the substrate holding stage in the processing container,
Cleaning gas containing ClF3 in a processing vessel under reduced pressure
Supply through the perforated plate toward the substrate mounting table, and heating the substrate mounting table within the range of its corrosion resistance temperature by operating the heating means for the substrate mounting table in the processing vessel. The film can be efficiently and safely removed at a large cleaning speed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing the entire configuration of a cold wall type single wafer CVD apparatus for performing a cleaning method according to an embodiment of the present invention.

FIG. 2 is a graph showing characteristics of an etching rate with respect to a pressure in a cleaning method according to an example.

FIG. 3 is a graph showing characteristics of an etching rate with respect to a flow rate of ClF3 gas in the cleaning method according to the embodiment.

FIG. 4 is a graph showing characteristics of an etching rate with respect to a flow rate of N2 gas in the cleaning method according to the embodiment.

FIG. 5 is a graph showing characteristics of an etching rate with respect to a total flow rate of a cleaning gas in the cleaning method according to the embodiment.

FIG. 6 is a table showing the respective corrosion resistance temperatures for various materials of ClF3 which can be used for the heatable portion in the cold wall type processing apparatus.

FIG. 7 is a graph showing characteristics of an etching rate with respect to a temperature in a cleaning method according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Processing container 12 Susceptor 14 Semiconductor wafer 22 Reaction gas supply system 24 Cleaning gas supply system 30 ClF3 gas supply unit 32 N2 gas supply unit 48 Removal device

Continuation of front page (56) References JP-A-3-47968 (JP, A) JP-A-1-231936 (JP, A) JP-A-3-243688 (JP, A) JP-A-3-252130 (JP) JP-A-4-280987 (JP, A) JP-A-4-58530 (JP, A) JP-A-4-171834 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB Name) C23C 16/44 H01L 21 / 205,21 / 31

Claims (7)

(57) [Claims] 1. A processing container capable of being evacuated, a substrate mounting table for mounting and supporting a substrate to be processed in the processing container, and heating for heating the substrate to be processed via the substrate mounting table in a film forming process. means and said group of predetermined process gas for film formation in the film formation process
Processing gas supply means for supplying a processing gas into the processing container via a perforated plate facing the plate mounting table; and cleaning gas supply means for supplying a cleaning gas containing ClF3 to the processing container via the perforated plate in the cleaning step. And a vacuum exhaust unit that exhausts the gas in the processing container via a predetermined exhaust path while maintaining the inside of the processing container at a predetermined degree of vacuum in each of the film forming process step and the cleaning step, In a cleaning step, a heating operation of the heating means for the substrate mounting table is turned on, and a cold wall type for removing a film adhered to the substrate mounting table in a state where the substrate mounting table is heated within a range of its corrosion resistance temperature. Film formation processing equipment. 2. The material of the substrate mounting table is quartz.
The cold wall forming film according to claim 1, wherein
Processing equipment. 3. The substrate mounting table is made of alumina (Al2).
The call of claim 1, wherein the call is O3).
Wall forming film processing equipment. 4. The material of the substrate mounting table is silicon carbide.
(SiC).
Shield wall forming film processing equipment. 5. The substrate mounting table is made of aluminum nitride.
2. The method according to claim 1, wherein
Cold wall forming film processing equipment. 6. The cleaning step, wherein
Exhaust means evacuates the processing chamber to a pressure of 1 to 50 Torr
The method according to any one of claims 1 to 5, wherein
Cold wall processing equipment. 7. The cleaning step in the cleaning step.
Cleaning gas supply means includes ClF3 and N2 in the processing vessel.
And the etching gas containing ClF3 with respect to the flow rate of N2.
It is characterized by supplying at a flow rate where the flow rate ratio is 0.2 or more
The cold war according to any one of claims 1 to 6.
Processing equipment.