JP3729578B2 - Semiconductor manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a semiconductor manufacturing technique, and more particularly to a semiconductor manufacturing method for removing reaction byproducts in a CVD (Chemical Vapor Deposition) apparatus.To the lawRelated.
[0002]
[Prior art]
The technology described below has been studied by the present inventors in researching and completing the present invention, and the outline thereof is as follows.
[0003]
Silicon nitride film deposition technology using dichlorosilane gas and ammonia gas, especially when a low-pressure CVD apparatus is used, silicon nitride deposited on the inner wall of a reaction furnace (also referred to as a vacuum processing vessel) or a jig for supporting a semiconductor wafer When the accumulated film thickness reaches about 1 μm, ammonium chloride as a reaction by-product adheres to the inside of the exhaust pipe (exhaust part), back diffuses into the furnace, and adheres as foreign matter on the wafer. Are known.
[0004]
As for the hot wall type CVD apparatus, Kogyo Kenkyukai Co., Ltd., issued on November 22, 1991, “November issue of electronic materials, VLSI manufacturing / test equipment guidebook <1992 version”, 29-34. Page.
[0005]
[Problems to be solved by the invention]
However, in the low-pressure CVD apparatus in the above-described technology, a reaction by-product adheres to the inside of the exhaust pipe, so that it takes a long time to maintain the exhaust pipe.
[0006]
Furthermore, since ammonium chloride adheres to the surface of the semiconductor wafer when the semiconductor wafer is carried in and out, there arises a problem that the yield of the semiconductor wafer (product) is lowered.
[0007]
  An object of the present invention is to improve a semiconductor wafer yield and reduce a maintenance frequency.The lawIt is to provide.
[0008]
The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.
[0009]
[Means for Solving the Problems]
Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
[0010]
  That is, the semiconductor manufacturing method according to the present invention performs a predetermined process on the semiconductor wafer in the processing unit of a vacuum processing container including a processing unit for processing a semiconductor wafer and a gas introduction unit and an exhaust unit communicating with the processing unit. After that, a step of supplying a purge gas into the vacuum processing container and sublimation into the vacuum processing container by controlling at least one or both of the degree of vacuum in the vacuum processing container and the temperature of the exhaust part Forming an atmosphere and sublimating the reaction by-product generated in the vacuum processing container; and exhausting the reaction by-product together with the purge gas.Introducing the purge gas from the gas introduction part on one side of the vacuum processing container and flowing the purge gas to the exhaust part on the other side of the vacuum processing container through the processing part; and introducing the gas on the other side And introducing the purge gas from a section and flowing the purge gas through the processing section to the one-side exhaust section, and each process is performed at least once.
[0011]
As a result, the reaction by-product generated in the vacuum processing container can be sublimated, that is, converted into a gas. As a result, the reaction by-product that has been changed to a gas is exhausted together with the purge gas. Reaction by-products can be removed.
[0012]
Therefore, it is possible to prevent the reaction by-product from staying inside the exhaust part of the vacuum processing container, and thereby the frequency of maintenance in the semiconductor manufacturing apparatus can be reduced.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0018]
FIG. 1 is a structural conceptual diagram showing an example of an embodiment of a structure of a semiconductor manufacturing apparatus according to the present invention in a partial cross section, and FIG. 2 shows an example of an embodiment of a structure of a control system of a semiconductor manufacturing apparatus according to the present invention. FIG. 3 is a control block diagram, FIG. 3 is a sublimation curve diagram showing an example of an embodiment of sublimation conditions for a reaction by-product (ammonium chloride) generated in the semiconductor manufacturing apparatus of the present invention, and FIG. 4 is in the semiconductor manufacturing method of the present invention. It is a control flow which shows an example of embodiment of the procedure of sequence control.
[0019]
The semiconductor manufacturing apparatus according to the present embodiment is a hot wall type two-sheet transfer simultaneous deposition type low-pressure CVD apparatus that performs film formation processing (predetermined processing) on the semiconductor wafer 1, and in this embodiment, is a process gas. A case where a silicon nitride film is formed on the semiconductor wafer 1 using dichlorosilane gas and ammonia gas will be described.
[0020]
Therefore, the reaction by-product generated in this case is ammonium chloride (3SiH₂Cl₂+ 10NH_Three→ Si_ThreeN_Four+ 6NH_FourCl + 6H₂).
[0021]
The configuration of the low-pressure CVD apparatus will be described. Through a vacuum processing container 2 provided with a processing unit 2a that is shielded from outside air and performs film formation on the semiconductor wafer 1, and a gas introduction unit 2b that communicates with the processing unit 2a. A vacuum for exhausting the process gas or purge gas 3 out of the vacuum processing vessel 2 through a gas supply means 4 for supplying the process gas or purge gas 3 to the processing section 2a and an exhaust pipe 2c (exhaust section) communicating with the processing section 2a. The pump 7 (exhaust means), the heater 5 as the main heating means for heating the processing unit 2a, and the vacuum processing container 2 are controlled in a sublimation atmosphere in which ammonium chloride as a reaction by-product generated therein is sublimated. After the film forming process on the semiconductor wafer 1 is completed, the control unit 10 sublimates the ammonium chloride and purges the ammonium chloride. It is intended to exhaust along with the scan 3.
[0022]
That is, the vacuum processing container 2 in the low-pressure CVD apparatus according to the present embodiment has the gas introduction part 2b, the processing part 2a, and the exhaust pipe 2c, and the film forming process on the semiconductor wafer 1 is performed in the processing part 2a. Done.
[0023]
Here, the processing section 2a is a cylindrical member having a prismatic shape (which may be cylindrical) and is formed by a tube member 2d (also referred to as a reaction furnace) made of quartz, silicon carbide, or the like, and a heater 5 is provided outside the tube member 2d. Is arranged.
[0024]
That is, since the low-pressure CVD apparatus of the present embodiment is a hot wall type, the semiconductor wafer 1 is heated by the heater 5 through the tube member 2d during the film forming process (for example, the processing unit 2a and the semiconductor wafer 1 are Heat to about 600 to 900 ° C.).
[0025]
Further, the gas introduction part 2b is formed by a flange member 2e, and the exhaust pipe 2c is mounted inside the flange member 2e and is provided so as to protrude outward from the flange member 2e.
[0026]
Further, the vacuum processing container 2 is provided with a gate valve 8 for carrying in and out the semiconductor wafer 1 and an opening / closing valve 9 that opens and closes when maintenance of the pipe member 2d is performed. The processing container 2 can be hermetically sealed from the atmosphere of the outside air.
[0027]
The gate valve 8 and the opening / closing valve 9 each have a flange surface 8a or a flange surface 9a for keeping airtightness on the inner surface.
[0028]
Here, the gate valve 8 is opened and closed by the driving member 6, and the semiconductor wafer 1 is transferred by the transfer robot 15.
[0029]
Further, in the vacuum processing container 2 of the present embodiment, two gas introduction parts 2b and two exhaust pipes 2c corresponding to the two gas introduction parts 2b are connected to the process gas or purge gas 3 introduced from the gas introduction part 2b. A pair is provided on each of the one side 2f and the other side 2g of the vacuum processing container 2 so as to flow to the exhaust pipe 2c.
[0030]
That is, the vacuum processing container 2 of the low-pressure CVD apparatus of the present embodiment has two flow paths for gas such as process gas and purge gas 3.
[0031]
Here, the first pipe 11 provided with the first on-off valve 11a is connected to the gas introduction part 2b on one side 2f of the vacuum processing container 2, and the gas introduction part 2b on the other side 2g is connected to the first gas supply part 2b. A second pipe 12 having a second on-off valve 12a is connected to the exhaust pipe 2c on one side 2f, and a third pipe 13 having a third on-off valve 13a is connected to the other side 2g. The 4th piping 14 in which the 4th on-off valve 14a was installed is connected to this exhaust piping 2c.
[0032]
Therefore, by controlling the opening / closing of the four on-off valves by the control unit 10, the process gas or the purge gas 3 taken from the gas introduction unit 2b on the one side 2f flows to the exhaust pipe 2c on the other side 2g through the processing unit 2a. In addition, the process gas or purge gas 3 taken from the gas introduction part 2b on the other side 2g can be made to flow to the exhaust pipe 2c on the one side 2f via the processing part 2a.
[0033]
That is, when a gas such as process gas or purge gas 3 flows from the gas inlet 2b on the one side 2f to the exhaust pipe 2c on the other side 2g, the first on-off valve 11a and the fourth on-off valve 14a are opened and the second on-off is opened. The valve 12a and the third on-off valve 13a are closed.
[0034]
Further, when the gas flows from the gas introduction portion 2b on the other side 2g to the exhaust pipe 2c on the one side 2f, the second on-off valve 12a and the third on-off valve 13a are opened and the first on-off valve 11a and the fourth on-off valve are opened. The valve 14a is closed.
[0035]
The first piping 11 and the first on-off valve 11a connected to the gas introduction part 2b, and the second piping 12 and the second on-off valve 12a are provided in the same number as the type of the process gas.
[0036]
That is, in the present embodiment, since there are two types of process gases (dichlorosilane gas and ammonia gas), two first pipes 11 and two first gas pipes installed in each gas introduction section 2b are provided. The on-off valve 11a, the two second pipes 12, and the two second on-off valves 12a installed on the second pipe 12 are attached.
[0037]
Further, in the low pressure CVD apparatus of the present embodiment, the exhaust part heater 16 that is controlled by the control part 10 and is an exhaust part heating means for heating the exhaust pipe 2c is connected to the exhaust pipe 2c on the one side 2f and the exhaust pipe 2c on the other side 2g. It is provided on both the exhaust pipe 2c.
[0038]
This exhaust part heater 16 is installed, for example, on the outside of each exhaust pipe 2c, and heats the exhaust pipe 2c from the outside of the exhaust pipe 2c. In this embodiment, the heating temperature is controlled by the control unit 10. Controlled by.
[0039]
Moreover, the control part 10 which the low pressure CVD apparatus of this Embodiment has is the gas supply means 4, the vacuum pump 7, the heater 5, the exhaust part heater 16, the 1st on-off valve 11a, the 2nd on-off valve 12a, the 3rd on-off valve. 13a, the fourth on-off valve 14a, and the transfer robot 15 can be controlled.
[0040]
Thereby, the control part 10 can control the vacuum degree and temperature in the vacuum processing container 2, and also the kind of the said gas to supply and the temperature of the exhaust pipe 2c, and can adjust these to a predetermined setting value.
[0041]
That is, under the control of the control unit 10, a sublimation atmosphere for sublimating ammonium chloride can be formed in the vacuum processing container 2.
[0042]
The sublimation conditions for ammonium chloride can be derived from the sublimation curve shown in FIG. 3 using the degree of vacuum (pressure) and temperature in the vacuum processing container 2 as parameters.
[0043]
Further, the purge gas 3 according to the present embodiment is an inert gas.₂The case of gas will be described. Depending on the type of film formed on the semiconductor wafer 1, He, Ar, or NH_ThreeA gas such as may be used.
[0044]
The semiconductor manufacturing method of the present embodiment will be described.
[0045]
In the semiconductor manufacturing method, a film formation process is performed on the semiconductor wafer 1 using the low-pressure CVD apparatus of the present embodiment shown in FIG. 1, that is, the hot-wall type two-sheet simultaneous depot type low-pressure CVD apparatus, and then the low-pressure CVD. The reaction by-product produced | generated within the vacuum processing container 2 of an apparatus is removed.
[0046]
In the present embodiment, a silicon nitride film is formed on the semiconductor wafer 1 using two kinds of process gases (dichlorosilane gas and ammonia gas), and then generated in the vacuum processing container 2 at the time of film formation. The case where ammonium chloride is removed will be described.
[0047]
Further, the vacuum processing vessel 2 of the low-pressure CVD apparatus described here also has a processing unit 2a, a gas introduction unit 2b, and an exhaust pipe 2c (exhaust unit). In the vacuum processing vessel 2, two gases are introduced. One side of the vacuum processing vessel 2 so that the process gas or purge gas 3 introduced from the gas introduction part 2b flows into the exhaust pipe 2c through the processing part 2a is connected to the part 2b and the two exhaust pipes 2c corresponding thereto. 2f and the other side 2g, respectively. That is, it is a low-pressure CVD apparatus having two flow paths for gases such as the process gas and the purge gas 3.
[0048]
First, under the control of the control unit 10 shown in FIG. 2, the gate valve 8 of the vacuum processing container 2 is opened by the driving member 6, and the two semiconductor wafers 1 are transferred to the processing unit 2a in the tube member 2d using the transfer robot 15. A wafer carry-in 20 (see FIG. 4) is carried in, and then the gate valve 8 is closed.
[0049]
Thereby, the inside of the vacuum processing container 2 is shut off from outside air, that is, sealed.
[0050]
Thereafter, the heater 5 is controlled to perform wafer heating 21 for heating the processing unit 2a of the vacuum processing container 2 to a predetermined temperature via the tube member 2d.
[0051]
In the present embodiment, for example, the temperature is detected by the temperature sensor 17 provided in the processing unit 2a, and thereby the processing unit 2a and the semiconductor wafer 1 are heated to 600 to 900 ° C.
[0052]
Subsequently, the gas supply means 4 and the vacuum pump 7 are controlled, the first on-off valve 11a of the first pipe 11 and the fourth on-off valve 14a of the fourth pipe 14 are opened, and the second on-off valve of the second pipe 12 is opened. 12a and the third on-off valve 13a of the third pipe 13 are closed, and the first process gas introduction 22 is performed.
[0053]
That is, the two types of process gases, each controlled to a predetermined flow rate using the gas flow meter 19, are separately introduced into the gas introduction part 2b on the one side 2f. Thereafter, the two kinds of introduced process gases flow through the processing section 2a to the exhaust pipe 2c on the other side 2g.
[0054]
At this time, the gas flow meter 19 and the pressure sensor 18 for detecting the pressure in the vacuum processing container 2 are used, and the gas supply means 4 and the vacuum pump 7 are controlled by the control unit 10 so that the inside of the vacuum processing container 2 is maintained. Maintain a predetermined degree of vacuum (pressure).
[0055]
In this state, a silicon nitride film having a desired thickness can be formed on the semiconductor wafer 1 by flowing the process gas for a predetermined time.
[0056]
Thereafter, by closing the first on-off valve 11a of the first pipe 11 and the second on-off valve 12a of the second pipe 12, the introduction of the process gas is stopped, and the third on-off valve 13a of the third pipe 13 and the fourth The fourth open / close valve 14a of the pipe 14 is opened and the vacuum pump 7 is controlled to perform the vacuum exhaust 23 for adjusting the inside of the vacuum processing container 2 to a predetermined degree of vacuum.
[0057]
Subsequently, the gas supply means 4 and the vacuum pump 7 are controlled, the second on-off valve 12 a of the second pipe 12 and the third on-off valve 13 a of the third pipe 13 are opened, and the first on-off valve of the first pipe 11 is opened. 11a and the fourth on-off valve 14a of the fourth pipe 14 are closed, and the second process gas introduction 24 is performed.
[0058]
That is, the two types of process gases, each controlled to a predetermined flow rate using the gas flow meter 19, are separately introduced into the gas introduction part 2b on the other side 2g. Thereafter, the introduced process gas flows through the processing section 2a to the exhaust pipe 2c on the one side 2f.
[0059]
At this time, similarly to the first process gas introduction 22, the gas flow meter 19 and the pressure sensor 18 for detecting the pressure in the vacuum processing container 2 are used, and the gas supply means 4 and the vacuum pump 7 are controlled by the control unit 10. By controlling, the inside of the vacuum processing container 2 is kept at a predetermined degree of vacuum (pressure).
[0060]
In this state, similarly to the first process gas introduction 22, a silicon nitride film having a desired thickness can be formed on the semiconductor wafer 1 by flowing the process gas for a predetermined time.
[0061]
The second process gas introduction 24 is for uniformly depositing the silicon nitride film on the semiconductor wafer 1, and the process gas is caused to flow in the opposite direction in the first and second processes in the processing section 2a. Thus, uniform film formation can be performed on the semiconductor wafer 1.
[0062]
However, the number of times the process gas is introduced is not limited to two, and the number can be changed as necessary.
[0063]
Thereafter, the film forming process end determination 25 is executed.
[0064]
That is, if a silicon nitride film having a desired thickness can be formed, the film forming process is terminated, and if not, the film forming process is repeated.
[0065]
When the silicon nitride film is formed, ammonium chloride, which is a reaction by-product, adheres to the inside of the vacuum processing vessel 2, particularly to the inner wall of the exhaust pipe 2c that is the exhaust part.
[0066]
Subsequently, after the film forming process is completed, the gate valve 8 is opened by the control unit 10, and the wafer unloading 26 for taking out the semiconductor wafer 1 from the vacuum processing container 2 using the transfer robot 15 is performed, so that the semiconductor wafer 1 is placed at a predetermined position. Transport.
[0067]
Further, after the semiconductor wafer 1 is unloaded from the vacuum processing container 2, a purge process in the vacuum processing container 2 is performed.
[0068]
The purge gas 3 in the present embodiment is N₂Gas.
[0069]
First, the exhaust section heater 16 is controlled while detecting the temperature of the temperature sensor 17 provided in the exhaust pipe 2c by the control section 10 shown in FIG. 2, whereby the temperature of the exhaust pipe 2c is set to 80 to 180 ° C., preferably Heat to 150 ° C.
[0070]
Subsequently, the gas supply means 4 and the vacuum pump 7 are controlled, the first on-off valve 11a of the first pipe 11 and the fourth on-off valve 14a of the fourth pipe 14 are opened, and the second on-off valve of the second pipe 12 is opened. 12 a and the third on-off valve 13 a of the third pipe 13 are closed, and the first purge gas introduction 27 is performed.
[0071]
In the present embodiment, the gas flow meter 19 is used, and the control unit 10 controls the N to be 1 l / min or more, preferably 4 l / min.₂Flow gas (purge gas 3) for 5 minutes.
[0072]
This is because N per unit time is set so that the amount of the purge gas 3 is three times or more the internal volume of the pipe member 2d (reactor).₂For example, in the case of the tube member 2d used for the film forming process of the semiconductor wafer 1 having a diameter of up to 200 mm, it is appropriate to flow 4 l / min for 5 minutes. Because.
[0073]
As a result, the purge gas 3 introduced from the gas introduction part 2b on the one side 2f of the vacuum processing container 2 flows through the treatment part 2a to the exhaust pipe 2c on the other side 2g.
[0074]
At this time, the gas flow meter 19 and the pressure sensor 18 for detecting the pressure in the vacuum processing container 2 are used, and the gas supply means 4 and the vacuum pump 7 are controlled by the control unit 10, thereby The pressure is kept at 80 Pa.
[0075]
Thereafter, by closing the first on-off valve 11a of the first pipe 11 and the second on-off valve 12a of the second pipe 12, the introduction of the purge gas 3 is stopped, and the third on-off valve 13a and the fourth pipe of the third pipe 13 are stopped. The fourth on-off valve 14a is opened, and the vacuum pump 7 is controlled to perform the vacuum exhaust 28 for adjusting the pressure in the vacuum processing container 2 to about 0.1 Pa.
[0076]
That is, the vacuum processing container 2 is depressurized to about 0.1 Pa to form an ammonium chloride sublimation atmosphere in the vacuum processing container 2.
[0077]
At this time, the temperature of the exhaust pipe 2c may be 150 ° C. or a temperature other than this.
[0078]
The time for performing the pressure reduction may be, for example, about 5 minutes, but may be other time.
[0079]
That is, it is only necessary that the pressure and temperature in the vacuum processing container 2 (particularly the temperature of the exhaust pipe 2c) satisfy the conditions for sublimating ammonium chloride using the ammonium chloride sublimation curve diagram shown in FIG.
[0080]
For example, as shown in FIG. 3, when the pressure in the vacuum processing container 2 is 60 Pa, it is necessary to adjust the temperature of the exhaust pipe 2c to about 150 ° C. or more, and when the pressure in the vacuum processing container 2 is 200 Pa, It is necessary to adjust the temperature of the exhaust pipe 2c to about 170 ° C. or higher.
[0081]
Thereby, the ammonium chloride adhering in the exhaust pipe 2c on the other side 2g can be sublimated, and the sublimated ammonium chloride can be exhausted together with the purge gas 3.
[0082]
Thereafter, the controller 10 shown in FIG. 2 controls the gas supply means 4 and the vacuum pump 7, opens the second on-off valve 12 a of the second pipe 12 and the third on-off valve 13 a of the third pipe 13, and The first on-off valve 11a of the pipe 11 and the fourth on-off valve 14a of the fourth pipe 14 are closed, and the second purge gas introduction 29 is performed.
[0083]
In the second purge gas introduction 29 as well, the gas flow meter 19 is used, and the purge gas 3 controlled by the control unit 10 at 1 l / min or more, preferably 4 l / min, is allowed to flow for 5 minutes.
[0084]
As a result, the purge gas 3 introduced from the gas introduction part 2b on the other side 2g of the vacuum processing container 2 flows into the exhaust pipe 2c on the one side 2f through (via) the processing part 2a, and the inside of the vacuum processing container 2 again reaches 80 Pa. Increase pressure.
[0085]
After the pressure increase, by closing the first on-off valve 11a of the first pipe 11 and the second on-off valve 12a of the second pipe 12, the introduction of the purge gas 3 is stopped, and the third on-off valve 13a of the third pipe 13 and the second on-off valve 12a The fourth open / close valve 14a of the four pipes 14 is opened and the vacuum pump 30 is controlled to perform the vacuum exhaust 30 for adjusting the pressure in the vacuum processing container 2 to about 0.1 Pa.
[0086]
That is, as in the case of the vacuum evacuation 28, the vacuum processing container 2 is depressurized to about 0.1 Pa to form a sublimation atmosphere of ammonium chloride in the vacuum processing container 2.
[0087]
At this time, similarly to the case of the vacuum exhaust 28, the temperature of the exhaust pipe 2c may be 150 ° C. or a temperature other than this, and the time for performing the pressure reduction is, for example, 5 Minutes may be used, but other time may be used.
[0088]
That is, it is only necessary that the pressure and temperature in the vacuum processing container 2 (particularly the temperature of the exhaust pipe 2c) satisfy the conditions for sublimating ammonium chloride using the ammonium chloride sublimation curve diagram shown in FIG.
[0089]
Thereby, the ammonium chloride adhering in the exhaust pipe 2c on the one side 2f can be sublimated, and the sublimated ammonium chloride can be exhausted together with the purge gas 3.
[0090]
Thereafter, the purge process end determination 31 is executed.
[0091]
Here, in the work shown in FIG. 4, the first work from the purge gas introduction 27 to the vacuum exhaust 30, that is, the purge process is performed until the operator gives an instruction to end the purge process.
[0092]
In the present embodiment, in the low-pressure CVD apparatus, after the film forming process is completed, until the next film forming process is started, that is, the low-pressure CVD apparatus forms a silicon nitride film (film forming process). Therefore, when the vacuum processing container 2 is not used, the purge process is continued until the operator gives an instruction to end the purge process.
[0093]
However, even when the low-pressure CVD apparatus is not performing the film formation process, it is needless to say that the purge process is not necessarily performed if ammonium chloride is not adhered in the vacuum processing container 2. Yes.
[0094]
In addition, the purge gas 3 is introduced from the gas introduction part 2b on one side 2f of the vacuum processing container 2, and the purge gas 3 is caused to flow to the exhaust pipe 2c on the other side 2g of the vacuum processing container 2 through the processing part 2a. The introduction of the purge gas 3 from the 2 g gas introduction part 2b and the flow of the purge gas 3 to the exhaust pipe 2c on the one side 2f through the processing part 2a are preferably performed a plurality of times by repeating each pair intermittently. .
[0095]
It goes without saying that the number of intermittent repetitions can be changed depending on the degree of adhesion of ammonium chloride.
[0096]
According to the semiconductor manufacturing method and apparatus of the present embodiment, the following operational effects can be obtained.
[0097]
That is, after the film formation process is performed on the semiconductor wafer 1, the purge gas 3 is supplied into the vacuum processing container 2, and the degree of vacuum in the vacuum processing container 2 or the temperature of the exhaust pipe 2c is controlled to enter the vacuum processing container 2. By forming a sublimation atmosphere of ammonium chloride (reaction by-product), the ammonium chloride generated in the vacuum processing vessel 2 can be sublimated, that is, changed from solid to gas.
[0098]
As a result, it is possible to remove ammonium chloride from the vacuum processing container 2 by exhausting the ammonium chloride changed into a gas together with the purge gas 3.
[0099]
Therefore, it is possible to prevent ammonium chloride from staying in the exhaust pipe 2c of the vacuum processing container 2, thereby reducing the frequency of maintenance in the low-pressure CVD apparatus (semiconductor manufacturing apparatus).
[0100]
In this embodiment, the cumulative film thickness of the silicon nitride film on the tube member 2d, which is a guideline for maintenance of the low-pressure CVD apparatus, can be reduced to about 2.5 μm (about 1 μm in the conventional low-pressure CVD apparatus). As a result, the frequency of maintenance can be greatly reduced.
[0101]
Furthermore, since ammonium chloride can be prevented from continuing to adhere to the exhaust pipe 2c, ammonium chloride can be prevented from adhering to the semiconductor wafer 1 when the semiconductor wafer 1 is carried in and out.
[0102]
Thereby, the yield of the semiconductor wafer 1 can be improved.
[0103]
Further, when the purge gas 3 flows in the vacuum processing container 2, the purge gas 3 is introduced from the gas introduction part 2b on one side 2f of the vacuum processing container 2, and the purge gas 3 is supplied to the other side of the vacuum processing container 2 through the processing part 2a. Flowing the exhaust gas 2c on the side 2g, introducing the purge gas 3 from the gas introduction part 2b on the other side 2g, and flowing the purge gas 3 to the exhaust pipe 2c on the one side 2f through the processing part 2a several times ( By performing both at least once), back diffusion of ammonium chloride into the vacuum processing container 2 can be prevented.
[0104]
As a result, it is possible to prevent ammonium chloride and other foreign matters from adhering in the vacuum processing container 2 and dilute the produced ammonium chloride.
[0105]
Thereby, the quantity of ammonium chloride produced | generated in the vacuum processing container 2 can be reduced, As a result, adhesion of ammonium chloride in the vacuum processing container 2 can be reduced.
[0106]
Further, after the film forming process on the semiconductor wafer 1 is completed, the purge gas 3 is caused to flow from the gas introduction unit 2b to the exhaust pipe 2c through the processing unit 2a, whereby the purge gas 3 heated by the processing unit 2a is discharged to the exhaust pipe 2c. Therefore, the inside of the exhaust pipe 2c can be heated by the heated purge gas 3.
[0107]
Thereby, when heating the exhaust piping 2c, it can heat efficiently.
[0108]
As mentioned above, the invention made by the present inventor has been specifically described based on the embodiments of the invention. However, the present invention is not limited to the embodiments of the invention, and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.
[0109]
For example, in the above embodiment, when the degree of vacuum in the vacuum processing container is controlled or the pressure is reduced, the introduction of the purge gas from the gas introduction unit is stopped by closing the first on-off valve and the second on-off valve. As described above, when controlling the degree of vacuum in the vacuum processing vessel or reducing the pressure in the vacuum processing vessel, the purge gas is introduced with the first on-off valve and the second on-off valve open. The degree of vacuum or the pressure reduction may be controlled by controlling the amount or the amount of vacuum exhaust.
[0110]
That is, when forming a sublimation atmosphere of ammonium chloride in the vacuum processing container 2 in the above-described embodiment, the purge gas 3 is introduced from the gas introduction part 2b on the one side 2f or the other side 2g to bring the inside of the vacuum processing container 2 to 80 Pa. Then, the first on-off valve 11a and the second on-off valve 12a are opened, the third on-off valve 13a and the fourth on-off valve 14a are also opened, and the flow rate of the purge gas 3 is set to 0 to 2 l / min. Run for about a minute (however, it may be other than 5 minutes).
[0111]
Furthermore, it is possible to form a sublimation atmosphere of ammonium chloride in the vacuum processing container 2 by heating the temperature of the exhaust pipe 2c to 150 ° C. or higher.
[0112]
In the above embodiment, the semiconductor manufacturing apparatus is a low-pressure CVD apparatus. However, the semiconductor manufacturing apparatus forms a silicon nitride film, a polycrystalline silicon film, an epitaxial silicon film, a silicon oxide film, or a tantalum oxide film. Other possible film forming apparatuses may be used, and further, an oxidation apparatus that performs heat treatment or oxidation treatment on the semiconductor wafer, or a doping apparatus that implants impurities from the vapor phase into the semiconductor wafer may be used.
[0113]
That is, when the semiconductor manufacturing apparatus shown in FIG. 1 is used and the process gas is replaced with a predetermined gas, and the predetermined processing is performed under the processing conditions for the semiconductor wafer, The generated reaction by-products are produced by the same method as the semiconductor manufacturing method of the above embodiment (however, the conditions for forming a sublimation atmosphere in the vacuum processing container are the same as that for each process on the semiconductor wafer or reaction by-products. The reaction by-product can be sublimated and exhausted.
[0114]
In this case, the semiconductor manufacturing method performs a predetermined process on the semiconductor wafer by the processing unit of a vacuum processing container including a processing unit in which a semiconductor wafer is processed and a gas introduction unit and an exhaust unit communicating with the processing unit. Supplying a purge gas into the vacuum processing container, and controlling at least one of or both of the degree of vacuum in the vacuum processing container and the temperature of the exhaust section to create a sublimation atmosphere in the vacuum processing container. Forming and sublimating the reaction by-product generated in the vacuum processing vessel, and evacuating the reaction by-product together with the purge gas.
[0115]
【The invention's effect】
Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.
[0116]
(1). After performing predetermined processing on the semiconductor wafer, by controlling at least one of the degree of vacuum in the vacuum processing container or the temperature of the exhaust part to form a sublimation atmosphere in the vacuum processing container, The reaction by-product generated in step 1 can be sublimated. As a result, by exhausting the reaction by-product together with the purge gas, it is possible to prevent the reaction by-product from staying in the vacuum processing container, thereby reducing the frequency of maintenance in the semiconductor manufacturing apparatus.
[0117]
(2). Since reaction by-products can be prevented from continuing to adhere to the inside of the exhaust part, reaction by-products can be prevented from adhering to the semiconductor wafer when the semiconductor wafer is carried in and out. Thereby, the yield of a semiconductor wafer can be improved.
[0118]
(3). When flowing the purge gas in the vacuum processing container, the purge gas is introduced from the gas introduction part on one side of the vacuum processing container and the purge gas is passed through the processing part to the exhaust part on the other side of the vacuum processing container; The back-diffusion of reaction by-products into the vacuum processing vessel is prevented by introducing the purge gas from the gas introduction part and flowing the purge gas through the treatment part to the exhaust part on one side at least once. Can do. As a result, the amount of reaction by-products generated in the vacuum processing container can be reduced, and thereby adhesion of reaction by-products in the vacuum processing container can be reduced.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a partial cross section of an example of an embodiment of a structure of a semiconductor manufacturing apparatus according to the present invention.
FIG. 2 is a control block diagram showing an example of an embodiment of a structure of a control system of a semiconductor manufacturing apparatus according to the present invention.
FIG. 3 is a sublimation curve diagram showing an example of an embodiment of sublimation conditions for a reaction byproduct (ammonium chloride) produced in the semiconductor manufacturing apparatus of the present invention.
FIG. 4 is a control flow showing an example of an embodiment of a sequence control procedure in the semiconductor manufacturing method of the present invention.
[Explanation of symbols]
1 Semiconductor wafer
2 Vacuum processing container
2a Processing unit
2b Gas introduction part
2c Exhaust piping (exhaust part)
2d pipe member
2e Flange member
2f One side
2g The other side
3 Purge gas
4 Gas supply means
5 Heater (Main heating means)
6 Drive member
7 Vacuum pump (exhaust means)
8 Gate valve
8a Flange surface
9 Open / close valve
9a Flange surface
10 Control unit
11 First piping
11a First on-off valve
12 Second piping
12a Second on-off valve
13 Third piping
13a Third on-off valve
14 Fourth piping
14a 4th on-off valve
15 Transfer robot
16 Exhaust section heater (exhaust section heating means)
17 Temperature sensor
18 Pressure sensor
19 Gas flow meter
20 Wafer loading
21 Wafer heating
22 First process gas introduction
23 Vacuum exhaust
24 Second process gas introduction
25 Determining film formation process completion
26 Wafer unloading
27 First purge gas introduction
28 Vacuum exhaust
29 Second purge gas introduction
30 Vacuum exhaust
31 End of purge process

Claims (3)

After the semiconductor wafer is subjected to a predetermined process in the processing section of the vacuum processing container comprising a processing section for processing the semiconductor wafer and a gas introduction section and an exhaust section communicating with the processing section, a purge gas is introduced into the vacuum processing container. A process of supplying
A sublimation atmosphere is formed in the vacuum processing container by controlling at least one of or both of the degree of vacuum in the vacuum processing container and the temperature of the exhaust part, and a reaction byproduct generated in the vacuum processing container. Sublimating the product;
Evacuating the reaction by-product together with the purge gas ,
Introducing the purge gas from the gas introduction part on one side of the vacuum processing container and flowing the purge gas to the exhaust part on the other side of the vacuum processing container through the processing part; and from the gas introduction part on the other side Introducing the purge gas and flowing the purge gas through the processing section to the exhaust section on the one side, and performing each process at least once . After performing the film forming process on the semiconductor wafer in the processing unit of a vacuum processing container including a processing unit for processing a semiconductor wafer and a plurality of gas introduction units and a plurality of exhaust units communicating with the processing unit, the vacuum processing is performed. Introducing a purge gas from a gas introduction part on one side of the container and flowing the purge gas through the processing part to an exhaust part on the other side of the vacuum processing container;
Either or both of decompression in the vacuum processing container and heating of the exhaust part are performed to form a sublimation atmosphere in the vacuum processing container and sublimate reaction by-products generated in the vacuum processing container. Process,
Introducing the purge gas from the gas introduction part on the other side and flowing the purge gas through the processing part to the exhaust part on the one side to increase the pressure in the vacuum processing container;
After increasing the pressure, either or both of the pressure reduction in the vacuum processing container and / or the heating of the exhaust part is performed to form a sublimation atmosphere in the vacuum processing container, and a reaction by-product generated in the vacuum processing container A sublimation process,
And a step of exhausting the reaction byproduct together with the purge gas. Claim 1 or is a semiconductor manufacturing method of the second aspect, when performing control or pressure reduction in the vacuum degree of the vacuum processing vessel, stopping the introduction of the purge gas from the gas inlet or introduction of the purge gas A method of manufacturing a semiconductor, comprising performing control of the amount or control of a vacuum exhaust amount.

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