JPH11150112A - Semiconductor manufacturing system and manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an oxidation-resistant nitride film containing oxygen at a specific concentration or lower on a semiconductor substrate by providing a means, which connects an etching chamber for removing natural oxide films formed on the substrate to a rapid thermal nitriding chamber, in which thermal nitride films are formed on the substrates in a high vacuum or inert gas atmosphere. SOLUTION: A semiconductor manufacturing device is provided with a cassette loader 101, which sets a substrate cassette 100 and a transportation chamber 103 connected to the loader 101 and provided with a transporting arm 102 and connects to a vapor phase etching chamber 104 by the use of a hydrogen fluoride and a quick thermal nitriding chamber 105 to the transportation chamber 103. In addition, a vacuum pipe and a vacuum pump are installed to each of the transportation chamber 103, a vapor phase etching chamber 104, and a rapid thermal nitriding chamber 105. Thereafter, the excessive formation of oxide film on the surfaces of semiconductor substrates can be prevented in the succeeding oxidizing process, by forming highly oxidation- resistant nitride films containing oxygen at a concentration of <=40 ppm on the surface of the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus characterized by a rapid thermal nitridation step in the manufacture of LSI memories such as DRAMs and flash memories, and a method of manufacturing a semiconductor device using the manufacturing apparatus.

[0002]

2. Description of the Related Art In recent years, DRAMs (Dynamic Random Acceses) have been developed.
A thermal nitride film formed by rapid thermal nitridation (RTN (Rapid Thermal Nitridation)) is widely used for the capacity of a memory cell and a gate insulating film of a s memory. FIG. 13 shows a schematic view of a conventional rapid thermal nitriding apparatus. In the conventional apparatus, after the semiconductor substrate cassette 31 is set on the cassette loader 31, the transfer arm 32
The semiconductor substrate is transported into the rapid thermal nitridation chamber 33 to form a thermal nitride film. The inside of the rapid thermal nitridation chamber is usually purged with an inert gas such as nitrogen. After the semiconductor substrate is carried into the rapid thermal nitridation chamber, for example, ammonia gas, which is a nitriding species, is introduced. Is heated to form a thermal nitride film.

[0003]

However, this technique has the following problems.

That is, in forming a thermal nitride film, if the oxygen concentration in the nitride film exceeds 40 ppm, resistance to oxidizing species is lost, and the nitride film is easily oxidized (1995 Japan Society of Applied Physics). Autumn Union Lectures Proceedings 27a-ZB-1).

If the nitride film loses its resistance to oxidizing species, the thickness of the nitride film becomes small as a result, and a necessary capacity cannot be secured.

The cause of this oxidation may be oxygen contained in the raw material ammonia, but rather, when nitriding, a natural oxide film formed on the semiconductor substrate by oxygen in air forms oxygen and oxygen. It is considered that a trace amount of oxygen remaining in each chamber of the semiconductor manufacturing apparatus is often used.

In the former case, even if the natural oxide film on the surface of the semiconductor substrate is removed by an etching gas such as hydrogen fluoride before the thermal nitriding treatment, the natural oxide film is removed again from the etching chamber to the RTN processing chamber. Exposure to air causes a natural oxide film to be formed again. In the latter case, a small amount of oxygen always remains in the chamber even when the semiconductor substrate is carried into the apparatus and air is entrapped.

As described above, in the conventional manufacturing apparatus, it is difficult to control the oxygen concentration in the nitride film to 40 ppm or less, and it has been difficult to form a nitride film having high resistance to oxidizing species in semiconductor manufacturing.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and solves the above-mentioned problems and provides a semiconductor manufacturing apparatus and a semiconductor device capable of reducing the oxygen concentration in a thermal nitride film. It is intended to provide a manufacturing method.

That is, the present invention is a semiconductor manufacturing apparatus having a means for removing an oxide film on a semiconductor substrate and a means for forming a thermal nitride film, wherein the means for removing the oxide film and the thermal nitride film are provided. A semiconductor manufacturing apparatus comprising: means for connecting a means for forming under a high vacuum or an atmosphere of an inert gas.

In the semiconductor manufacturing apparatus according to the present invention, the semiconductor substrate is preferably a silicon semiconductor substrate. Further, the means for removing the oxide film on the semiconductor substrate preferably etches the semiconductor substrate with an etching gas after transporting the semiconductor substrate into an etching chamber, and the etching gas is preferably hydrogen fluoride. . Further, the means for removing the oxide film preferably treats the semiconductor substrate with an etching gas after reducing the pressure in the etching chamber to 1 × 10 ⁻³ Pa or less.

Preferably, the means for forming the thermal nitride film performs a rapid thermal nitridation process in a rapid thermal nitridation chamber.

Preferably, the means for connecting the means for removing the oxide film and the means for forming the thermal nitride film under a high vacuum or in an atmosphere of an inert gas preferably includes a step of rapidly removing the semiconductor substrate from the etching chamber. Into the thermal nitriding chamber, under high vacuum, more preferably, the pressure in the apparatus is 3
The semiconductor substrate is transported at a pressure of × 10 ⁻³ Pa or less or in an atmosphere of an inert gas such as a nitrogen gas or an argon gas.

In the semiconductor manufacturing apparatus according to the present invention, the means for forming the thermal nitride film preferably comprises: setting the pressure in the rapid thermal nitridation chamber to 1 × 10 ⁻³ Pa or less or an inert gas atmosphere; The semiconductor substrate is heated at 800 to 1200 ° C. in the chamber in the presence of ammonia gas. The thermal nitride film is preferably a silicon nitride film.

Further, the present invention provides a method of manufacturing a semiconductor device, comprising the steps of: etching a semiconductor substrate in a gas phase; and performing a thermal nitridation process after the etching. And a method of manufacturing a semiconductor device, wherein the semiconductor substrate is held under a high vacuum or in an atmosphere of an inert gas during the step of performing the thermal nitriding treatment.

The method for manufacturing a semiconductor device according to the present invention is preferably used by the semiconductor manufacturing apparatus.

Hereinafter, the present invention will be described in detail.

As described above, the present invention provides a means for removing an oxide film on a semiconductor substrate, a means for forming a thermal nitride film, a means for removing the oxide film, and a means for forming the thermal nitride film. Are connected under high vacuum or in an inert gas atmosphere.

FIG. 1 shows an outline of a semiconductor manufacturing apparatus according to the present invention. The apparatus shown in FIG. 1 includes an etching chamber 104 for removing a natural oxide film on the surface of a semiconductor substrate, a rapid thermal nitridation processing chamber 105 for forming a thermal nitride film on a semiconductor substrate, and the semiconductor substrate. And a transfer chamber 103 for transfer to the chamber.

The interiors of the chambers can be sealed from each other, and are connected to each other so that the semiconductor substrates are transported under a high vacuum or in an inert gas atmosphere.

The semiconductor substrate used in the present invention comprises:
A silicon semiconductor substrate that may be doped with impurities such as phosphorus, arsenic, boron, and gallium is preferable.

In the present invention, high vacuum means that the pressure in the system is 1 × 10 ⁻³ Pa or less, preferably 2 × 10 ⁻⁴ Pa.
It means a state of Pa or less. When each operation is performed at a pressure in the system of 1 × 10 ⁻³ Pa or more, a natural oxide film is formed on the surface of the semiconductor substrate by a trace amount of oxygen remaining in the system, and as a result,
It is not preferable because 40 ppm or more of oxygen is taken into the thermal nitride film.

In the etching chamber 104,
A pipe capable of supplying an etching gas such as hydrogen fluoride and CF ₄ and an inert gas such as nitrogen gas and argon gas is provided. The rapid thermal nitriding chamber 1
A pipe capable of supplying a nitride source such as ammonia, nitrogen and hydrazine and an inert gas such as nitrogen gas (high-purity oxygen-free gas) and argon gas are also provided in 05.

The operation of the semiconductor manufacturing apparatus according to the present invention is as follows.

First, after a semiconductor substrate is set in the cassette 100 housed in the cassette housing part 101 of the semiconductor manufacturing apparatus of the present invention, the inside of the transfer chamber 103, the etching chamber 104 and the rapid thermal nitriding chamber 105 are set in a turbo molecular chamber. A high vacuum is applied by a vacuum pump such as a pump, and each chamber is sealed. In the present invention,
The operation of filling each chamber with a high vacuum or an inert gas may be performed simultaneously as described above, or may be performed separately.

Next, in the transfer chamber 103,
After the oxygen in the system is removed as much as possible by filling an inert gas such as a nitrogen gas or an argon gas, the semiconductor substrate is transferred to the etching chamber 104. The inside of the etching chamber 104 is also preferably set to a high vacuum or an inert gas atmosphere in order to prevent a natural oxide film from being formed again after etching the semiconductor substrate surface.

A natural oxide film due to oxygen in the air exists on the semiconductor substrate. When this natural oxide film is present, oxygen is taken into the nitride film from the natural oxide film in the next thermal nitridation treatment, and the oxygen concentration in the nitride film is increased. Therefore, a step of removing the natural oxide film is required.

Next, after the semiconductor substrate is transferred into the etching chamber 104, the chamber is closed. Next, an oxide film on the surface of the semiconductor substrate is removed by etching using an etching gas such as a hydrogen fluoride gas. At this time, it is preferable to fill the inside of the etching chamber 104 again with a high vacuum or an inert gas before the etching in order to completely remove oxygen from the system.

As a method of etching in the etching chamber 104, for example, hydrogen fluoride, CF ₄
Gas etching, plasma etching, sputter etching, ion beam etching, and the like using an etching gas such as

Next, the semiconductor substrate from which the natural oxide film has been removed by etching is transferred to a rapid thermal nitridation chamber 105, the chamber 105 is sealed, and a nitride source is supplied at a temperature of 800 to 1200 ° C. For example, from 1 minute
By heating for 5 minutes, a nitride film is formed on the semiconductor substrate. As the nitride source, ammonia, nitrogen,
Hydrazine and the like can be mentioned, and ammonia is preferably used in view of handleability, cost and the like. It is preferable that the inside of the rapid thermal nitridation chamber 105 is again set to a high vacuum or filled with an inert gas before the rapid thermal nitridation treatment, since oxygen can be completely removed.

Thereafter, the heating of the rapid thermal nitridation chamber and the supply of the nitride source are stopped, the chamber is evacuated by a vacuum pump, and the semiconductor substrate is taken out, thereby completing the rapid thermal nitridation step by the semiconductor manufacturing apparatus of the present invention.

The semiconductor manufacturing apparatus of the present invention can
It can be preferably used for forming an insulating film of an AM or a flash memory and a silicon nitride film as a dielectric film.

According to the manufacturing apparatus of the present invention, the oxygen concentration is 4
A nitride film of 0 ppm or less can be formed. Such a nitride film has excellent oxidation resistance. Therefore, it is possible to prevent an oxide film from being formed more than necessary in the subsequent oxidation step, and it is possible to secure a capacity required for the nitride film.

According to a second aspect of the present invention, a step of placing a semiconductor substrate in an atmosphere of high vacuum or an inert gas, a step of etching the semiconductor substrate, and a step of performing rapid thermal nitridation after the etching are performed. A method for manufacturing a semiconductor device, comprising:

As a semiconductor substrate that can be used in the present invention, a silicon semiconductor substrate that may be doped with impurities such as phosphorus, arsenic, boron, and gallium is preferable.

The step of placing the semiconductor substrate in a high vacuum or an atmosphere of an inert gas includes placing the semiconductor substrate in a high vacuum or in an atmosphere of an inert gas such as a nitrogen gas or an argon gas before the etching step. It is. This is because by removing oxygen gas from the system as much as possible, even if the natural oxide film on the surface of the semiconductor substrate is removed with an etching gas such as hydrogen fluoride before thermal nitriding, it is exposed to air again. This is to prevent the formation of a natural oxide film again.

In the present invention, high vacuum means a state in which the pressure in the system is 1 × 10 ⁻³ or less, preferably 2 × 10 ⁻⁴ or less. When each operation is performed at a pressure in the system of 1 × 10 ⁻³ Pa or more, a natural oxide film is formed on the surface of the semiconductor substrate due to a small amount of oxygen remaining in the system, and as a result, 40 ppm is contained in the thermal nitride film. Thus, oxygen is taken in.

In the step of etching the semiconductor substrate in a gas phase, the semiconductor substrate is placed in a high vacuum or an inert gas atmosphere, and then the surface of the semiconductor substrate is naturally oxidized in the presence of an etching gas such as hydrogen fluoride. This is a step of removing the film by etching. As an etching method, for example,
A so-called dry etching method such as gas etching, plasma etching, sputter etching, or ion beam etching using an etching gas such as hydrogen fluoride or CF ₄ can be used.

In the next step of performing a rapid thermal nitridation treatment, the nitride film is heated on the semiconductor substrate in a temperature range of 800 to 1200 ° C., for example, for 1 to 5 minutes in the presence of a nitride source. It is formed. Examples of the nitride film include a silicon nitride film. Further, as the nitride source,
Ammonia, nitrogen, hydrazine and the like can be mentioned, but ammonia is preferably used from the viewpoint of handleability and cost. It is preferable to make the inside of the system a high vacuum or fill it with an inert gas before the rapid thermal nitriding treatment in order to completely remove oxygen.

After the nitride film is formed on the semiconductor substrate as described above, the semiconductor substrate is taken out, and the rapid thermal nitridation process of the semiconductor device manufacturing method of the present invention is completed.

According to the method of manufacturing a semiconductor device of the present invention,
For example, a silicon nitride film as an insulating film or a dielectric film of a DRAM or a flash memory can be preferably used.

According to the production method of the present invention, the oxygen concentration is 4
A nitride film of 0 ppm or less can be formed. Such a nitride film has excellent oxidation resistance. Therefore, it is possible to prevent an oxide film from being formed more than necessary in the subsequent oxidation step, and it is possible to secure a capacity required for the nitride film.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a semiconductor device and a method of manufacturing the semiconductor device according to the present invention will be described with reference to the embodiments.
This will be described in more detail.

First Embodiment First, FIG. 2 shows a conceptual diagram of a semiconductor manufacturing apparatus according to a first embodiment of the present invention. In this embodiment, FIG.
As shown in FIG. 2, a cassette loader 101 for installing a substrate cassette 100, a transfer chamber 103 having a transfer arm 102 connected to the cassette loader 101, and a gas phase etching chamber 104 of hydrogen fluoride and a rapid thermal nitridation chamber 105 are transferred. Each is connected to the chamber 103.

As shown in FIG. 3, a vacuum pipe 106 and a vacuum pump 107 are connected to the transfer chamber 103. As shown in FIG. 4 and FIG. The thermal nitriding chamber 105 is also provided with vacuum pipes 108 and 109 and vacuum pumps 110 and 111, respectively.

Further, the rapid thermal nitriding chamber 105
The vacuum pump 111 is connected to a high vacuum pump 112 such as a turbo molecular pump for evacuating to a high vacuum. This vacuum pump system includes switching valves 113 and 11.
4 enables switching between the processing exhaust pipes 115 and 116 for the vapor phase etching and the rapid thermal nitridation processing.

Further, a pipe 117 for supplying hydrogen fluoride is provided in the vapor phase etching chamber 104, and a pipe 11 for supplying ammonia gas is provided in the rapid thermal nitriding chamber 105.
8, and the inert gas supply pipes 119 and 120 are connected to each other.

FIG. 6 shows a flow chart of forming a silicon nitride film on a silicon semiconductor substrate by rapid thermal nitridation using the above semiconductor manufacturing apparatus.

First, the silicon semiconductor substrate is set in a cassette in the transfer chamber 103, and the pressure in the transfer chamber is set to about 0.13 Pa.

Next, the semiconductor substrate is previously set at 0.13 Pa
Vapor phase etching chamber 1 evacuated to a degree
04 is transported using the transport arm 102 and the substrate is set. Next, nitrogen gas, which is an inert gas, is purged by about 1 SLM, the exhaust is switched to 115, hydrogen fluoride gas is introduced into the chamber 103, and the natural silicon oxide film on the silicon semiconductor substrate is etched. Next, after evacuation of the hydrogen fluoride in the system by an exhaust pump, nitrogen gas is purged by about 1 SLM, and vacuuming is performed again using the vacuum pump.

Next, the etched silicon semiconductor substrate is again transferred to the transfer chamber 103 by using the transfer arm 102.
Transport to At this time, it is preferable that the inside of the transfer chamber 102 is evacuated again by a vacuum pump in some cases.

Next, the silicon semiconductor substrate is transported by the transport arm 102 into the rapid thermal nitriding chamber 105, which has been evacuated to about 0.13 Pa, and the substrate is set.

Thereafter, the rapid thermal nitriding chamber 105
Using a high vacuum exhaust pump 112, for example,
After evacuating to about 3 × 10 ⁻⁴ Pa, piping 118
, An ammonia gas is introduced into the chamber 105, and at the same time, the exhaust is switched to the processing exhaust 116. Then, the silicon semiconductor substrate is heated to 850 ° C. by a lamp, for example.
Then, the thermal silicon nitride film is formed by a process of about 1 minute.

Next, the supply of ammonia is stopped, the chamber is evacuated by the vacuum pump 111, and the chamber is evacuated again to take out the silicon semiconductor substrate. By repeating the above operation, all the substrates are subjected to the rapid thermal nitridation process, the transfer chamber is returned to the atmospheric pressure, the cassette 100 of the silicon semiconductor substrate is taken out, and the rapid thermal nitridation process is completed.

According to the semiconductor manufacturing apparatus of this embodiment, a nitride film having an oxygen concentration of 40 ppm or less can be formed. Such a nitride film has excellent oxidation resistance. Therefore, it is possible to prevent an oxide film from being formed more than necessary in the subsequent oxidation step, and it is possible to secure a capacity required for the nitride film.

Second Embodiment In the second embodiment of the present invention, the configuration of each chamber is the same as in the first embodiment. However, the transfer chamber 103
(For the sake of convenience, the same components are denoted by the same reference numerals. The same applies hereinafter.) The difference is that a pipe 121 for constantly flowing an inert gas is connected. FIG. 7 shows a conceptual diagram of the transfer chamber 103 of the second embodiment. In the present embodiment, the pipe 121 also serves as an inert gas supply pipe.

FIG. 8 is a flowchart of forming a silicon nitride film on a silicon semiconductor substrate by rapid thermal nitridation using the above semiconductor manufacturing apparatus. In the following description, the same components as those in the first embodiment are not shown.

First, the silicon semiconductor substrate is set in a cassette in the transfer chamber 103, and the inside of the transfer chamber is evacuated to about 0.13 Pa. Next, the pipe 121
, A nitrogen gas as an inert gas is supplied into the chamber, and the semiconductor substrate is placed under a nitrogen gas atmosphere.

Next, in the same manner as in the first embodiment, the transfer arm 102 is placed in the vapor phase etching chamber 104 in which the semiconductor substrate has been evacuated to about 0.13 Pa in advance.
Then, the natural silicon oxide film on the silicon semiconductor substrate is etched by hydrogen fluoride gas. And
The etched silicon semiconductor substrate is transported again into the transport chamber 103, and the silicon semiconductor substrate is transported into the rapid thermal nitridation chamber 105 which has been evacuated to about 0.13 Pa in advance. After evacuation is performed to, for example, about 1.3 × 10 ⁻⁴ Pa using the high vacuum evacuation pump 112, ammonia gas is introduced into the rapid thermal nitridation chamber 105 from the pipe 118, and the silicon semiconductor is irradiated with a lamp. The substrate is heated to, for example, about 1000 ° C., and a thermal silicon nitride film is formed by processing for about 1 minute.

Next, the supply of ammonia was stopped, the inside of the chamber was evacuated by the vacuum pump 111, the chamber was evacuated again, the silicon semiconductor substrate was taken out, and the transfer chamber was returned to atmospheric pressure.
00 is taken out, and the rapid thermal nitriding treatment is completed.

According to the semiconductor manufacturing apparatus of this embodiment, a nitride film having an oxygen concentration of 40 ppm or less can be formed as in the first embodiment. Such a nitride film has excellent oxidation resistance. Therefore, it is possible to prevent an oxide film from being formed more than necessary in the subsequent oxidation step, and it is possible to secure a capacity required for the nitride film.

Third Embodiment A third embodiment of the present invention is an example of manufacturing a DRAM using the method of manufacturing a semiconductor device according to the present invention.

FIG. 9 shows a vertical sectional view of a DRAM at the completion of a cell manufactured by the manufacturing method of the present invention. As shown in FIG. 1, first, LOCOS oxidation (Local Oxidation of Silicon) is performed on a silicon semiconductor substrate 2 to form a selectively oxidized region 3 and an active region 4 where elements are formed in other regions. Have been.

In the selective oxidation region 3 and the active region 4, for example, word lines 6 made of polysilicon are formed via thin oxide films 7, respectively. In particular, the word line in the active region 4 forms the gate electrode 9 of the MOSFET 8. Side walls 10 made of an insulating film are formed on both sides of the gate electrode 9, respectively.
On the semiconductor substrate 2 side, an LDD (Lightly Doped Dr.
ain), an active region 11 (source and drain regions) having a profile unique to the FET structure is formed. The active region 11 is formed by performing ion implantation twice before and after the formation of the sidewall 10. Then, the gate electrode 9 and the word line 6 are covered with an insulating layer 12 made of, for example, a silicon oxide film or a phosphorus-containing film (PSG film) and an etch stopper layer 13 made of, for example, a silicon nitride film. The insulating layer 12 and the etch stopper layer 13 have an active region 14 on the selective oxidation region 3 side.
Is formed, and a lower electrode 16 of the memory capacitor is provided through the contact hole 15.

The lower electrode 16 is formed in the contact hole 15
Three fins are provided at predetermined intervals around a column extending upward from the fin. And silicon nitride /
An upper electrode 18 is formed via a dielectric film 17 made of silicon oxide, thereby constituting a memory capacitor 19.

Next, a method for manufacturing the DRAM will be described.

FIG. 10 is a schematic sectional view showing a main part of a manufacturing process of the DRAM according to the third embodiment of the present invention. It should be noted that, for simplification, all elements and wirings other than the memory capacitors are omitted in FIG.

First, after LOCOS oxidation is performed to form a gate oxide film, word lines and MOSFET electrodes are simultaneously formed. After that, through shallow ion implantation, sidewall formation, and deep ion implantation, the MOS transistor having the LDD structure is formed.
The step of forming the FET is completed. Then, an insulating layer and an etching stopper layer are formed on the entire surface.

In FIG. 10A, the layer denoted by reference numeral 21 formed first on the semiconductor substrate 20 indicates this etching stopper layer. On the etching stopper layer 21, the first
Layer 22 and the second layer 23 alternately one or more times,
Here, lamination is repeated three times. These two types of layers 2
2 and 23 function as a so-called "mold" in order to obtain the fin shape of the lower electrode of the memory capacitor.

Next, as shown in FIG. 10B, a connection hole 24 that penetrates the first layer 22 and the second layer 23 and reaches the active layer of the MOSFET (not shown) is opened. The opening of the connection hole 24 is formed by using the patterned resist 25 as a mask. For example, RIE using a fluoride-based gas such as CF ₄ can be performed at a time.

Subsequently, as shown in FIG. 10 (C), the first and second connection holes 24 extend laterally from the inner wall of the connection hole 24.
Either one of the second layers 22 and 23 is selectively etched. In the present embodiment, the wafer is immersed in a hydrogen fluoride-based etchant or sprayed with hydrofluoric acid vapor or the like. The first layer 22 was isotropically etched.

Thereafter, as shown in FIG. 10D, the portion removed by this etching and the connection hole 24 are buried, and the lower electrode is made of polysilicon so as to cover the first and second layers 22 and 23. The third layer 26 is, for example,
The film is formed by a CVD method. At this time, an impurity may be implanted into the polysilicon layer 26.

Next, the first layer 22 and the second layer 23
Is removed from the surface side by, for example, a photo etching method.

As described above, the memory capacitor can be completed.

Next, the memory obtained as described above
As shown in FIG. 11, for example, a semiconductor substrate with a capacitor is formed by using the semiconductor manufacturing apparatus used in the first embodiment.
After removing oxygen gas as much as possible under a high vacuum of 2 × 10 ⁻³ Pa or in an inert gas atmosphere such as nitrogen gas, the natural silicon oxide film on the surface is continuously removed by etching, and rapid thermal nitriding is performed. A silicon nitride film 27 is formed on the surface. Next, a silicon nitride film 28 is further formed by a CVD method, and the total thickness of the nitride film is set to 5 to 6 nm. Then, a thin oxide film having a thickness of 1 to 2 nm is formed on the nitride film 28 by, for example, a thermal oxidation method. A silicon film 29 is formed. FIG. 12 shows a state diagram obtained as described above.

The reason why the silicon nitride film is further formed by the CVD method after the rapid thermal nitridation treatment is to secure a sufficient film thickness. The reason for this is to prevent leakage current from easily occurring while having a large dielectric constant to improve the amount of stored charges in the MOS element.

Next, after patterning the silicon oxide film 29 and obtaining a predetermined shape by photoetching, an upper electrode layer made of polysilicon is formed on the silicon oxide film 29 by, for example, a CVD method. By doing
The memory capacitor of the DRAM shown in FIG. 9 is completed.

The DRAM manufactured as described above is
It has a nitride film having an oxygen concentration of 40 ppm or less. Such a nitride film has excellent oxidation resistance. Therefore,
Since it is possible to prevent an oxide film from being formed more than necessary in the subsequent oxidation step, it is possible to obtain a high-performance DRAM having a sufficient capacity required for the nitride film.

[0079]

According to the semiconductor manufacturing apparatus and the semiconductor device manufacturing method of the present invention, a semiconductor manufacturing apparatus having a nitride film having an oxygen concentration of 40 ppm or less can be obtained. Such a nitride film has excellent oxidation resistance. Therefore, it is possible to prevent an oxide film from being formed more than necessary in the subsequent oxidation step, and it is possible to secure a capacity required for the nitride film.

The DRAM or flash memory manufactured as described above has a nitride film having an oxygen concentration of 40 ppm or less and excellent in oxidation resistance. Therefore, it is possible to prevent an oxide film from being formed more than necessary in the subsequent oxidation step, and it is possible to obtain a high-performance DRAM or flash memory in which the capacity required for the nitride film is sufficiently ensured.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a semiconductor manufacturing apparatus of the present invention.

FIG. 2 is a schematic diagram of a semiconductor manufacturing apparatus of the present invention.

FIG. 3 is a schematic view of a transfer chamber of the semiconductor manufacturing apparatus of the present invention.

FIG. 4 is a schematic diagram of an etching chamber of the semiconductor manufacturing apparatus of the present invention.

FIG. 5 is a schematic diagram of a rapid thermal nitriding chamber of the semiconductor manufacturing apparatus of the present invention.

FIG. 6 is a flowchart of a rapid thermal nitridation process of a semiconductor substrate using the semiconductor manufacturing apparatus of the present invention.

FIG. 7 is a schematic diagram of a transfer chamber of the semiconductor manufacturing apparatus of the present invention.

FIG. 8 is a flowchart of a rapid thermal nitridation process of a semiconductor substrate using the semiconductor manufacturing apparatus of the present invention.

FIG. 9 is a schematic sectional view of a DRAM manufactured by the method of manufacturing a semiconductor device according to the present invention.

FIG. 10 is a diagram illustrating a DRA according to a method of manufacturing a semiconductor device of the present invention;
It is a principal part schematic sectional drawing which shows each process of M manufacture. (A)
The first and second layers are alternately formed on the etch stopper layer by 3
FIG. 3B is a diagram in which a contact hole is opened and then a resist film is formed, and FIG.
(D) is a diagram in which a third layer for forming an electrode in a portion removed by etching and a contact hole is coated, and FIG. Etches the third layer over the entire surface,
It is the figure which isolate | separated the lower electrode, and (F) is the figure which completed the formation of the fin-shaped lower electrode.

11 is a view in which a thermal silicon nitride film is formed from the state shown in FIG. 10 by a semiconductor manufacturing method of the present invention, and then a silicon nitride film is further formed by a CVD method.

12 is a view in which a silicon oxide film is formed from the state shown in FIG.

FIG. 13 is a schematic diagram showing a conventional semiconductor manufacturing apparatus.

[Explanation of symbols]

100, 31: cassette, 101, 30: cassette loader, 102, 32: transport arm, 103: transport chamber, 104: etching chamber, 105, 33 ...
Rapid thermal nitriding chamber, 106, 108, 109 ...
Vacuum piping, 107, 110, 111 ... vacuum pump, 1
12: high vacuum pump, 113, 114: switching valve, 115, 116: processing exhaust pipe, 117: HF supply pipe, 118: ammonia supply pipe, 119, 1
Reference numeral 20: inert gas purging pipe, 2, 20: silicon semiconductor substrate, 3: selective oxidation region, 4: active region, 5
... Element isolation film, 6 ... Word line, 7 ... Gate oxide film, 8 ...
MOSFET, 9 gate electrode, 10 sidewall, 12 insulating layer, 13, 21 etching stopper layer, 11, 14 active region, 15, 24 contact hole, 16, 26 lower electrode, 17 silicon nitride / Dielectric film made of silicon oxide, 18 ... upper electrode, 19 ... memory
Capacitor, 22 first layer, 23 second layer, 25
Resist film, 27, 28: silicon nitride film, 29: silicon oxide film

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/8247 29/788 29/792

Claims (13)

[Claims] A means for removing an oxide film on a semiconductor substrate;
A semiconductor manufacturing apparatus having means for forming a thermal nitride film, wherein means for connecting the means for removing the oxide film and the means for forming the thermal nitride film under a high vacuum or an inert gas atmosphere is provided. Semiconductor manufacturing equipment. 2. The semiconductor manufacturing apparatus according to claim 1, wherein said semiconductor substrate is a silicon semiconductor substrate. 3. The semiconductor manufacturing apparatus according to claim 1, wherein the means for removing the oxide film on the semiconductor substrate is configured to carry the semiconductor substrate into an etching chamber and then perform etching with an etching gas. 4. The semiconductor manufacturing apparatus according to claim 3, wherein said etching gas is hydrogen fluoride. 5. The semiconductor manufacturing apparatus according to claim 1, wherein said means for forming a thermal nitride film performs a rapid thermal nitridation process in a rapid thermal nitridation chamber. 6. A means for connecting the means for removing the oxide film and the means for forming the thermal nitride film under high vacuum, wherein the semiconductor substrate is transferred from the etching chamber to the rapid thermal nitridation chamber under high vacuum. The semiconductor manufacturing apparatus according to claim 1, wherein the apparatus is transported. 7. A means for connecting the means for removing the oxide film and the means for forming the thermal nitride film under a high vacuum, wherein the pressure in the apparatus is changed from the etching chamber to the rapid thermal nitridation chamber by 3.times.10. The semiconductor manufacturing apparatus according to claim 1, wherein the semiconductor substrate is transported at a pressure of ^-3 Pa or less. 8. A means for connecting the means for removing the oxide film and the means for forming the thermal nitride film under an inert gas atmosphere includes an inert gas atmosphere from an etching chamber to a rapid thermal nitridation chamber. The semiconductor manufacturing apparatus according to claim 1, wherein the semiconductor substrate is transported by: 9. The semiconductor manufacturing apparatus according to claim 1, wherein said inert gas is a nitrogen gas or an argon gas. 10. The means for forming a thermal nitride film comprises: setting the pressure in a rapid thermal nitridation chamber to 1 × 10 ⁻³ Pa or less or in an atmosphere of an inert gas;
2. The semiconductor manufacturing apparatus according to claim 1, wherein the semiconductor substrate is heated at 800 to 1200 [deg.] C. in the presence of ammonia gas. 11. The semiconductor manufacturing apparatus according to claim 1, wherein said thermal nitride film is a silicon nitride film. 12. The method of removing an oxide film, comprising: setting the pressure in an etching chamber to 1 × 10 ⁻³ Pa or less;
The semiconductor manufacturing apparatus according to claim 1, wherein the semiconductor substrate is treated with an etching gas. 13. A method of manufacturing a semiconductor device, comprising: a step of etching a semiconductor substrate in a gas phase; and a step of performing a thermal nitridation process after the etching. A method for manufacturing a semiconductor device, wherein a semiconductor substrate is held under a high vacuum or an inert gas atmosphere during a step of performing a treatment.