JP2002093793A - Apparatus and method for forming insulation film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for forming an insulation film, having a small film thickness unevenness between a plurality of wafers, even when the films are continuously formed on the wafers. SOLUTION: The apparatus for forming the insulating film comprises a reduced pressure vessel, formed of a chamber dome 1 which is made of an insulator and a chamber body 2 made of a metal, a pressure-reducing means (4, 5 and 6) for reducing pressure in the vessel, a gas introducing port 3 for introducing a material gas of the insulating film in the container, a plasma- generating means (coil) 7 for generating plasma in the vessel, and a cooling pipe 8 provided at the dome 1 to fill a liquid or a liquefied gas therein. Since the liquid or the liquefied gas filled in the pipe 8 absorbs a hat of the dome 1 due to a radiation from the plasma, even if plurality of wafers are formed continuously without conducting cleaning works, the temperature of the dome 1 can be held constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an insulating film forming apparatus and an insulating film forming method, and more particularly to an inductively coupled plasma CVD apparatus capable of continuously forming an insulating film.

[0002]

2. Description of the Related Art Conventional inductively-coupled plasma CVD (Chem)
The ical vapor deposition apparatus has a reduced-pressure container on which a predetermined plasma process is performed, and the reduced-pressure container includes a chamber dome made of an insulating material and a chamber body made of metal. A coil is arranged on the outer periphery of the decompression container, and a susceptor is arranged inside the decompression container. In addition, a vacuum pump, a gas inlet, and the like are connected to the decompression container, respectively. First, a material gas is introduced from a gas introduction port into a decompression container reduced in pressure by a vacuum pump. Then, by applying a voltage to the coil, a plasma is formed in the decompression container, and an insulating film is formed on the wafer mounted on the susceptor. From the film formation conditions, the temperature of the wafer during film formation increases to a temperature of about 300 to 400 ° C.

Japanese Patent Application Laid-Open No. 7-99098 discloses a plasma processing apparatus having a vacuum vessel having a cavity for circulating a constant temperature fluid. By using this plasma device, by setting the temperature of the water so that the temperature of the inner wall of the vacuum vessel is lower than the sublimation temperature of the adhered film, the temperature fluctuation of the inner wall of the vacuum vessel is reduced, and the inner wall of the vacuum vessel is attached. The effect of preventing the adhesion film from being peeled off can be obtained.

[0004]

In the conventional inductively coupled plasma CVD apparatus, the temperature of the chamber dome 1 rises due to radiation from the plasma as the temperature of the wafer rises. Normally, the chamber dome after film formation is
By performing dry cleaning without using inductively coupled plasma after film formation, the temperature can be cooled to a temperature before film formation. However, due to demands such as a reduction in process time and a reduction in cost, it is desired to omit this cleaning operation and perform film formation continuously. When the continuous film formation is performed without performing the cleaning, the chamber dome 1 continues to receive the radiation from the plasma, and its temperature becomes 4 ° C.
The temperature rises above 00 ° C. Further, the film forming speed on the wafer increases as the temperature of the chamber dome increases. As a result, when continuous film formation is performed, the film thickness variation between wafers increases. If the temperature of the chamber dome further increases, the chamber dome itself may be damaged. Therefore, in order to reduce the variation in film thickness between wafers even when continuous film formation is performed, it is necessary to keep the temperature of the chamber dome during the continuous film formation constant between the wafers. Japanese Patent Application Laid-Open No. 7-99098 does not disclose how to suppress the temperature rise of the chamber when a continuous film is formed.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and an object of the present invention is to form an insulating film by continuously forming a film on a plurality of wafers. An object of the present invention is to provide an insulating film forming apparatus and an insulating film forming method capable of reducing the film thickness variation between wafers even in the case of the above.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, a first feature of the present invention is that a decompression container composed of a chamber dome made of an insulator and a chamber body made of metal, Pressure reducing means for reducing the pressure, and a gas inlet for introducing a material gas for the insulating film into the pressure reducing container,
Plasma generating means for generating plasma in the decompression vessel,
The present invention is an insulating film forming apparatus having a cooling pipe provided in a chamber dome and capable of filling a liquid or a liquefied gas therein.

Here, the insulator constituting the chamber dome includes, for example, glass (quartz), ceramics and the like. Other materials may be used as long as they are air-tight insulators capable of maintaining a reduced pressure state in the reduced-pressure container. The decompression means is capable of reducing the pressure to a degree necessary for generating plasma in the decompression container. For example, a rotary pump (RP), a turbo molecular pump (TMP) and the like are connected in series. The configuration is appropriate. Further, by arranging a variable valve capable of changing the opening degree in front of these pumps, it is possible to generate a reduced pressure state that accurately satisfies the plasma generation conditions. The gas inlet is provided in the vacuum container (preferably, in the chamber dome). A necessary amount of material gas for forming the insulating film flows out from the gas inlet. It is desirable that the flow rate of the material gas accurately satisfy the conditions for forming the insulating film via a variable flow rate valve (variable leak valve). The plasma generating means is desirably a coil spirally arranged along the outer periphery of the chamber dome. By applying a voltage to the coil, inductive coupling energy is formed in the depressurized container, and high-density plasma is generated in the depressurized container.

According to the first feature of the present invention, the inside of the decompression container is decompressed to a predetermined degree of vacuum by the decompression means, and the material gas introduced from the gas inlet is formed by the plasma generated by the plasma generation means. And is formed as an insulating film on the wafer placed in the reduced pressure container.
At this time, the liquid or liquefied gas filled in the cooling pipe provided in the chamber dome absorbs the heat of the chamber dome due to the radiation from the plasma. Therefore, even when an insulating film is continuously formed on a plurality of wafers without performing a cleaning operation, the temperature of the chamber dome can be kept constant, so that the film thickness between the wafers can be maintained. Variation can be reduced. Further, since the temperature of the chamber dome is maintained at a low temperature, the amount of film formation on the inner wall of the chamber dome decreases, and the precoat film formation performed on the chamber dome after cleaning can be omitted.

[0009] In the first aspect of the present invention, it is preferable that the cooling pipe is arranged at an arbitrary position inside the chamber dome. Alternatively, the cooling pipe may be arranged at any position outside the chamber dome. Furthermore, it may be arranged at any position inside the chamber dome.

A second feature of the present invention is that (1) a first step of mounting a wafer in a reduced-pressure container composed of a chamber dome made of an insulator and a chamber body made of metal, and (2) Form plasma in the decompression vessel,
A second step of forming an insulating film on the wafer; (3)
A third step of removing the wafer from the decompression container,
(4) If there is a next wafer, return to the first step, place the next wafer in the reduced pressure container, and if there is no next wafer, end a series of continuous film forming steps. In the method for forming an insulating film according to the above, at least in the second step, the inside of a cooling pipe provided in the chamber dome is filled with a liquid or a liquefied gas.

According to a second feature of the present invention, an insulating film is continuously formed on a plurality of wafers without performing a cleaning operation between a wafer processing and a next wafer processing. Even so, the temperature of the chamber dome can be kept constant, so that the film thickness variation between wafers can be reduced. Further, since the temperature of the chamber dome is maintained at a low temperature, the amount of film formation on the inner wall of the chamber dome decreases, and the precoat film formation performed on the chamber dome after cleaning can be omitted.

In the second aspect of the present invention, not only the second step but also a liquid or a liquid is always contained in the cooling pipe during a series of continuous film forming steps further including the first, third and fourth steps. A liquefied gas may be filled. Alternatively, the temperature of the chamber dome is measured during a series of continuous film forming steps, and when at least the temperature of the chamber dome is higher than a predetermined reference temperature, the inside of the cooling pipe is filled with a liquid or a liquefied gas. No problem.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, taking an inductively coupled plasma CVD apparatus as an example of an insulating film forming apparatus. FIG. 1 is a schematic diagram showing a configuration of an inductively coupled plasma CVD apparatus according to an embodiment of the present invention.

As shown in FIG. 1, an inductively coupled plasma CVD apparatus 11 according to an embodiment of the present invention comprises a decompression vessel (1, 2), a gas inlet 3, and decompression means (4, 5,.
6), a plasma generating means 7, a cooling pipe 8, and a slit valve 18. Decompression container (1,
2) is composed of a chamber dome 1 made of an insulator and a chamber body 2 made of metal. Here, the insulator constituting the chamber dome 1 is quartz glass. The gas inlet 3 is provided on the upper surface and the side surface of the chamber dome 1, and introduces a material gas necessary for forming an insulating film in the reduced pressure vessel (1, 2). The material gas is introduced at a flow rate that satisfies the conditions for forming the insulating film through a variable flow rate valve (variable leak valve). The decompression means comprises a variable valve 4, a turbo molecular pump (TMP) 5, and a rotary pump (RP) 6 connected in series, and decompresses the interior of the decompression containers (1, 2). By changing the opening of the variable valve 4, it is possible to generate a reduced pressure state that accurately satisfies the plasma generation conditions. The plasma generating means is a coil 7 spirally arranged along the outer periphery of the chamber dome 1. By applying a voltage to the coil 7, inductive coupling energy is formed in the depressurized containers (1, 2). High-density plasma is generated in the decompression vessel. A susceptor 10 for mounting the wafer 9 is installed in the decompression containers (1, 2). The plasma is formed in a space between the wafer 9 and the gas inlet 3 on the susceptor 10. The wafer 9 is loaded / unloaded into / out of the vacuum containers (1, 2) via the slit valve 18.

The cooling pipe 8 is arranged at an arbitrary position inside the chamber dome 1 and can be filled with a liquid or a liquefied gas. The liquid to be filled in the cooling pipe 8 is suitably water, oil, or the like, and the liquefied gas is suitably liquid nitrogen, liquid helium, or the like. FIG. 1 shows a cross-sectional structure of a cooling pipe 8 arranged inside the chamber dome 1. As shown in FIG.
Are arranged parallel to the inner and outer walls of the chamber dome 1. The cooling pipe 8 is connected to the chamber dome 1
Since it is arranged on the whole, the heat of the entire chamber dome 1 can be absorbed. The material of the cooling pipe 8 is not particularly limited as long as it does not impair the function of filling the inside of the chamber dome 1 with a liquid or a liquefied gas even at a temperature (300 to 400 ° C.). Alternatively, the cooling pipe 8 may be a space that is continuous in a pipe shape inside the chamber dome 1. That is, instead of the cooling pipe 8, the chamber dome 1 itself may have a function of filling the inside with a liquid or a liquefied gas. Further, a cooling device for cooling the liquid or the liquefied gas may be connected to both ends of the cooling pipe 8 to circulate the liquid or the liquefied gas in the cooling pipe 8. The cooling performance of the chamber dome 1 is further improved.

FIG. 2 is a schematic diagram showing how the wafer 9 is placed on the susceptor 10 and taken out. As shown in FIG. 2, by moving the slit valve 18 along the outer wall of the chamber body 2, the wafer 9A on the susceptor 10 can be taken out through the opening of the chamber body 2, and the susceptor 10 can be taken out. The wafer 9B can be mounted thereon.

The inductively coupled plasma CVD apparatus 11 shown in FIG. 1 and FIG. 2 is a single-wafer type film forming apparatus in which a decompression container (1, 2) is opened and a wafer is replaced every time one wafer is processed. This is an example. Even in the case of the same single-wafer apparatus, an inductively coupled plasma CVD apparatus 11 in an actual mass production facility
Has a plurality of chambers for efficient wafer processing. FIG. 3 is a plan view showing a chamber configuration of an insulating film forming apparatus including a plurality of chambers suitable for mass production equipment in the inductively coupled plasma CVD apparatus according to the embodiment of the present invention. Insulation film deposition equipment as mass production equipment consists of a plurality of process chambers in which actual deposition processing is performed, a plurality of load lock chambers in which cassettes containing wafers are set, and cooling of wafers after deposition processing And a transfer chamber for transferring a wafer among the process chamber, the load lock chamber, and the cooling chamber. The process chamber, load lock chamber, and transfer chamber are always kept in a vacuum state. During film formation, the load lock chamber is vented (open to the atmosphere), a wafer (cassette) is set, and the inside of the load lock chamber is evacuated. During this time, the process chamber and the transfer chamber are kept in a vacuum state. The wafer is transferred from the load lock chamber to the transfer chamber, and then transferred to the process chamber. After the film forming process is performed in the process chamber, the film is transferred again to the load lock chamber or the cooling chamber via the transfer chamber. Then, the next wafer is similarly transported in the order of load lock, transfer, and process chamber, and continuous film formation is performed.

Next, the inductively coupled plasma C shown in FIG.
A method for forming an insulating film using the VD device 11 will be described with reference to FIG. FIG. 4 is a flowchart showing a method of forming an insulating film according to the embodiment of the present invention.

(A) First, in step S01, the slit valve 18 is moved along the chamber body 2 as shown in FIG. 2 to open the depressurized containers (1, 2). Next, in step S02, one wafer 9 is carried into a reduced-pressure container (chamber). Then, in step S03, the wafer 9 is placed on the susceptor 10. Then, in step S04, the slit valve 18 is moved to close the opening of the chamber body 2 as shown in FIG. Next, in step S05, a gas serving as a material of the insulating film is introduced from the gas inlet 3. At this time, a material gas at a predetermined flow rate is introduced into the chamber via a variable flow rate valve (such as a variable leak valve) for adjusting the gas flow rate.

(B) Next, in step S06, a voltage is applied to the coil 7 to generate high-density plasma near the wafer 9 in the chambers (1, 2). Next, in step S07, water is circulated inside the cooling pipe 8 provided in the chamber dome 1. The water absorbs the heat of the chamber dome 1 due to the radiation from the plasma and prevents the temperature of the chamber dome 1 from rising. Next, step S08
At a predetermined degree of vacuum, gas flow rate, under the conditions of plasma density, the material gas activated by plasma,
A film is formed on the surface of the wafer 9 as an insulating film.

(C) Next, after the formation of the insulating film having a predetermined thickness is completed, in step S09, the voltage applied to the coil 7 is stopped, and the generation of plasma is terminated. Next, in step S10, the introduction of the material gas is stopped. Next, in step S11, the slit valve 18 is moved again along the chamber body 2 as shown in FIG. 2, and the decompression containers (1, 2) are opened. Then, in step S12, the wafer 9A mounted on the susceptor 10 is unloaded from the chamber. Next, in step S13, the slit valve 18 is moved to close the opening of the chamber body 2 as shown in FIG. Next, in Step S14, if there is a next wafer to be subjected to the film forming process (YES in Step S14), the process returns to Step S01, the slit valve 18 is opened, and the next wafer 9B is placed on the susceptor 10, Then, according to the above steps, the wafer 9A
A film forming process similar to that described above is performed. Here, the cleaning of the inside of the chamber is not performed between step S14 and step S01, and the process proceeds to the film forming process of the next wafer 9B continuously. If there is no next wafer 9B in step S14 (NO in step S14), a series of film forming steps for continuously forming a plurality of wafers is completed. Note that, in a series of continuous film forming steps, the rotary pump 6 and the turbo molecular pump 5 are continuously operated. In other words, the chamber is kept in a vacuum state not only at the time of the film forming process but also at the time of replacing the processing wafer in step S14.

As described above, according to the embodiment of the present invention, when an insulating film is formed on the wafer 9 placed in the depressurized container (1, 2), an arbitrary inside of the chamber dome 1 is formed. The liquid or liquefied gas filled in the cooling pipe 8 arranged at the position absorbs the heat of the chamber dome 1 due to the radiation from the plasma. Therefore, even when an insulating film is continuously formed on a plurality of wafers 9 without performing a cleaning operation, the temperature of the chamber dome 1 can be kept constant, so that the Can be reduced. Further, since the temperature of the chamber dome 1 is maintained at a low temperature, the amount of film formed on the inner wall of the chamber dome 1 is reduced, and the pre-coat film formation performed on the chamber dome 1 after cleaning can be omitted.

Although the case where the material forming the chamber dome 1 is quartz glass has been described, it is not limited to this. An insulating material such as ceramics, which has an airtight property capable of maintaining the reduced pressure state in the reduced pressure containers (1, 2), may be used. In addition, a configuration in which a rotary pump (RP), a turbo molecular pump (TMP), and the like are connected in series has been described as the decompression means, but the present invention is not limited to this. Decompression container (1,
A different type of vacuum pump may be used as long as the pressure can be reduced to a degree required for generating plasma in 2). Also, the case where the plasma generating means is the coil 7 is shown, but the present invention is not limited to this. No problem.

(First Modification) The cooling pipe 7 shown in FIGS. 1 and 2 is arranged at an arbitrary position inside the chamber dome 1, but the present invention is not limited to this. . The cooling pipe is provided in the chamber dome,
Other configurations may be used as long as they have a function of filling the inside with a liquid or a liquefied gas. In the first modified example, a case where the cooling pipe is arranged at an arbitrary position outside the chamber dome will be described with reference to FIG. FIG. 5 is a schematic diagram showing a configuration of an inductively coupled plasma CVD apparatus according to a first modification of the present invention. FIG.
As shown in the figure, the inductively coupled plasma CVD apparatus 12 according to the first modification includes a decompression vessel (14, 2), a gas inlet 3, a decompression means (4, 5, 6), and a plasma generation means. 7 and a cooling pipe 15. The decompression containers (14, 2) are composed of the chamber dome 14 and the chamber body 2. C shown in FIGS. 1 and 2
Although the configurations of the chamber dome 14 and the cooling pipe 15 are different from those of the VD device 11, the other components are the same. The same process elements are denoted by the same reference numerals and description thereof is omitted.

The chamber dome 14 is different from the chamber dome 1 shown in FIGS. 1 and 2 in that a cooling pipe 15 is not disposed inside the chamber dome 1. Decompression container (1
4, 2) Other points such as an insulating material such as quartz glass or ceramics having an airtightness capable of maintaining a reduced pressure state, and a point at which a joint portion with the chamber body 2 is subjected to an airtight treatment. The points are the same as those of the chamber dome 1 shown in FIGS.

On the other hand, the cooling pipe 15 is different from the cooling pipe 8 shown in FIGS. 1 and 2 in that it is arranged at an arbitrary position outside the chamber dome 14. The point of maintaining the function of filling the inside of the chamber dome 14 with a liquid or a liquefied gas even under the temperature of the chamber dome 14 (300 to 400 ° C.), the point of absorbing the heat of the entire chamber dome 14 by being disposed over the entire chamber dome 14, and the cooling. Pipe 15
The liquid to be filled into the inside of the pipe is suitably water, oil, and the like, and the liquefied gas is liquid nitrogen, liquid helium, and the like. Same as 8. FIG. 5 shows a cross-sectional structure of the cooling pipe 15 arranged outside the chamber dome 14. As shown in FIG. 5, the cooling pipe 15 extends along the outer wall of the chamber
4 are arranged all over. Of course, a cooling device for cooling the liquid or the liquefied gas may be connected to both ends of the cooling pipe 15 to circulate the liquid or the liquefied gas in the cooling pipe 15.

(Second Modification) In a second modification, a case where the cooling pipe is arranged at an arbitrary position inside the chamber dome will be described with reference to FIG. FIG. 6 is a schematic diagram showing a configuration of an inductively coupled plasma CVD apparatus according to a second modification of the present invention. As shown in FIG. 6, the inductively coupled plasma C according to the second modified example
The VD device 13 includes a decompression container (16, 2), a gas inlet 3, a decompression unit (4, 5, 6), and a plasma generation unit 7.
And a cooling pipe 17. The decompression container includes a chamber dome 16 and a chamber body 2. CVD apparatus 11 shown in FIGS. 1 and 2
Although the configurations of the chamber dome 16 and the cooling pipe 17 are different from those of the first embodiment, the other components are the same. The same process elements are denoted by the same reference numerals and description thereof is omitted.

The chamber dome 16 is different from the chamber dome 1 shown in FIGS. 1 and 2 in that the cooling pipe 17 is not disposed inside. Decompression container (1
6, 2) Other points such as the point that it is an insulator such as quartz glass or ceramics having airtightness capable of maintaining the reduced pressure state, and the point that the joint portion with the chamber body 2 is airtightly processed. The points are the same as those of the chamber dome 1 shown in FIGS.

On the other hand, the cooling pipe 17 is different from the cooling pipe 8 shown in FIGS. 1 and 2 in that it is arranged at an arbitrary position inside the chamber dome 16. The point of maintaining the function of filling the inside of the chamber dome 16 with a liquid or liquefied gas even under the temperature of the chamber dome 16 (300 to 400 ° C.), the point of absorbing the heat of the entire chamber dome 16 by being disposed over the entire chamber dome 16, and the cooling. Pipe 17
The liquid to be filled into the inside of the pipe is suitably water, oil, and the like, and the liquefied gas is liquid nitrogen, liquid helium, and the like. Same as 8. FIG. 6 shows a cross-sectional structure of the cooling pipe 17 arranged outside the chamber dome 16. As shown in FIG. 6, the cooling pipe 17 extends along the inner wall of the
4 are arranged all over. Of course, a cooling device for cooling the liquid or the liquefied gas may be connected to both ends of the cooling pipe 17 to circulate the liquid or the liquefied gas in the cooling pipe 17. Since the cooling pipe 17 in the second modification is exposed to the plasma space during the formation of the insulating film, the material of the cooling pipe 17 maintains the function of filling the inside with a liquid or a liquefied gas even in the plasma space. It is necessary to use something.

[0030]

As described above, according to the present invention, even when a plurality of wafers are continuously formed in forming an insulating film, the film thickness variation between wafers is reduced. It is possible to provide an insulating film forming apparatus and an insulating film forming method that can perform the method.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of an inductively coupled plasma CVD apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a state where a chamber dome and a chamber body of the inductively coupled plasma CVD apparatus shown in FIG. 1 are separated and a wafer is placed on a susceptor or a wafer on the susceptor is taken out. .

FIG. 3 is a plan view showing a chamber configuration of an insulating film forming apparatus including a plurality of chambers suitable for mass production equipment in the inductively coupled plasma CVD apparatus according to the embodiment of the present invention.

FIG. 4 is an inductively coupled plasma CV shown in FIGS. 1 and 2;
6 is a flowchart illustrating a method of forming an insulating film according to an embodiment of the present invention using the D apparatus.

FIG. 5 is a schematic diagram showing a configuration of an inductively coupled plasma CVD apparatus according to a first modification of the embodiment.

FIG. 6 is a schematic diagram showing a configuration of an inductively coupled plasma CVD apparatus according to a second modification of the embodiment.

[Explanation of symbols]

 1, 14, 16 Chamber dome 2 Chamber body 3 Gas inlet 4 Variable valve 5 Turbo molecular pump (TMP) 6 Rotary pump (RP) 7 Coil 8, 15, 17 Cooling pipe 9, 9A, 9B Wafer 10 Susceptor 11, 12 , 13 Inductively coupled plasma CVD equipment

Claims (5)

[Claims] 1. A decompression container comprising a chamber dome made of an insulator and a chamber body made of metal, a decompression means for decompressing the interior of the decompression container, and introducing a material gas for an insulating film into the decompression container. Insulation characterized by comprising: a gas inlet to be used; a plasma generating means for generating plasma in the decompression vessel; and a cooling pipe provided in the chamber dome and capable of filling a liquid or liquefied gas therein. Film forming equipment. 2. The insulating film forming apparatus according to claim 1, wherein the cooling pipe is disposed at an arbitrary position inside the chamber dome. 3. The insulating film forming apparatus according to claim 1, wherein the cooling pipe is arranged at an arbitrary position outside the chamber dome. 4. A first step of placing a wafer in a reduced-pressure container composed of a chamber dome made of an insulator and a chamber body made of metal; and forming a plasma in the reduced-pressure container to form the wafer. A second step of forming an insulating film thereon, a third step of taking out the wafer from the inside of the reduced-pressure container, and if there is a next wafer, returning to the first step,
Placing the next wafer in the depressurized container, and, if there is no next wafer, a fourth step of ending a series of continuous film forming steps. In the step, a liquid or a liquefied gas is filled in a cooling pipe provided in the chamber dome. 5. During a series of continuous film forming steps including the first step, the third step, and the fourth step in addition to the second step, a liquid is always contained in the cooling pipe. 5. The method according to claim 4, wherein the insulating film is filled with a liquefied gas.