JP2000077391A - Etching method and substrate processing apparatus - Google Patents

Abstract

An object of the present invention is to provide an etching method and a substrate processing apparatus for performing safe, high-speed, low-cost etching using a desired gas. SOLUTION: When etching is performed using ClF ₃ gas, by simultaneously supplying NO gas, etching and cleaning of plasma-free, low-cost, and high-speed silicon nitride can be performed. -S of a thin film forming apparatus for forming a silicon nitride film by sputtering
It is effective for itu (in place) cleaning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an etching method and a substrate processing apparatus, and particularly to chlorine trifluoride (ClF ₃ ).
The present invention relates to an etching method and a substrate processing apparatus for rapidly etching various substrates such as semiconductor wafers or deposits in a processing container using a gas.

[0002]

2. Description of the Related Art ClF ₃ gas is a strong fluorinated material,
At room temperature, silicon (Si) or silicon nitride (SiN _x )
Reacts with tungsten (W), molybdenum (Mo), etc. to form volatile fluorine compounds with a high vapor pressure, but hardly reacts with quartz or stainless steel forming the processing vessel of the thin film forming equipment It has been known. This is, for example, a ClF ₃ technical document provided by Iwatani Corporation and Central Glass Co., Ltd. (February 1995)
Are disclosed. Therefore, from around 1990, ClF ₃ gas began to be used as a cleaning gas in a processing container of a thin film forming apparatus mainly for amorphous silicon in the field of manufacturing semiconductor devices.

[0003]

Readily react with amorphous silicon [0008], is a ClF ₃ can achieve practically sufficient etching rate in terms of cost, the etching of the silicon nitride film (Si _x N _y) When applied, the reaction speed is slow, and ClF ₃ gas alone is 1/1 of polysilicon.
There is a drawback that only an etching rate of about 0 to 1/100 can be obtained (for example, ULSI Production Technology Emergency Report Editing Committee, "Wafer Cleaning Specifications and Problems of Semiconductor Manufacturers", Science Forum, p. 125).

As in the case of other chemical reactions, even when ClF ₃ gas is used, the etching rate for the silicon nitride film increases with increasing temperature. Therefore, if the etching target is heated to a high temperature, a practically sufficient etching rate can be obtained.

However, in practice, if the temperature is too high, the components inside the processing container are also etched, so that there is an upper limit of the processing temperature. The upper limit temperature is S
About 70 ° C when using US (stainless steel),
In the case where silicon carbide (SiC) is used, the temperature is around 250 ° C. The etching rate at this upper limit temperature is insufficient for application to an actual production apparatus, particularly a processing container cleaning process of a single wafer type thin film forming apparatus. Therefore, speeding up the etching of the silicon nitride film is a very important technical issue for realizing a practical single-wafer silicon nitride film forming apparatus.

On the other hand, another gas is added to ClF ₃ ,
Attempts have been made to increase the etching rate of the silicon nitride film. For example, ClF ₃ technical data (1995, provided by Iwatani Corporation and Central Glass Co., Ltd.)
It is reported that the etching rate of a silicon nitride film was increased about 5 times by adding 1% of HF (hydrofluoric acid) to ClF ₃ . However, H
Compared to ClF ₃ , F gas has the disadvantages of being extremely corrosive, toxic, and requiring careful handling. When HF is used, the metal pipe corrodes due to the slight moisture attached due to the release of the processing vessel or gas pipe to the atmosphere, which not only causes metal contamination, but in the worst case, a hole may be formed in the metal pipe. There is also.

For the etching of the silicon nitride film, a CDE (Chemical Dry Etching) method using CF ₄ / O ₂ / N ₂ or NF ₃ / O ₂ plasma is considered as an effective method. Furthermore, in a plasma etching method using CF ₄ / O ₂ plasma, it has been reported that the etching rate of a silicon nitride film increases when NO gas is present (MGBlain, TL Meisenheimer, and JESte).
vens, J. Vac. Sci. Technol. A14 (4), 2151 (1996)). However, in order to use plasma, additional equipment such as a microwave power supply or an RF power supply is required.
A technique for efficiently transporting the radicals generated by the plasma to the object to be etched is also required, so that the apparatus becomes complicated and the cost of the apparatus increases.

As described above in detail, when a silicon nitride film is etched using a conventional etching method and a substrate processing apparatus, a practically sufficient etching rate cannot be obtained by an inexpensive etching method without using plasma. There was a problem.

The present invention has been made based on the recognition of such a problem. That is, an object of the present invention is to provide an etching method and a substrate processing apparatus for eliminating the drawbacks of the conventional etching method and the substrate processing apparatus as described above and realizing safe, high-speed, low-cost etching using a desired gas. To provide.

[0010]

In order to achieve the above object, according to the present invention, when a deposit in a processing substrate or a processing vessel is etched using ClF ₃ gas, a NO gas is supplied at the same time. It is characterized by the following.

That is, according to the etching method of the present invention, NOF is added together with ClF ₃ gas into a processing vessel of a substrate processing apparatus.
The method is characterized in that a gas is supplied to etch a surface of a substrate to be processed placed inside the processing container or a product attached to the inside of the processing container.

The present invention works particularly effectively when the product adhered to the substrate to be processed or the inside of the processing vessel is silicon nitride.

It is preferable that the etching is performed while controlling the temperature of the product adhered to the substrate to be processed or the inside of the processing container.

Further, the inside of the processing container is 760 tons.
By performing etching at a reduced pressure of rr or less, vaporization of a reaction product with an etching gas is promoted to stabilize the etching, and leakage of the etching gas to the outside of the apparatus can be suppressed.

Meanwhile, the substrate processing apparatus of the present invention includes: a processing container, and a gas supply means for supplying a ClF ₃ gas and NO gas into the processing container, the inside of the processing container ClF ₃ The method is characterized in that the NO gas is supplied together with a gas to etch a product adhering to the surface of the substrate to be processed placed inside the processing chamber or the inside of the processing chamber.

Here, it is preferable that the apparatus further comprises temperature control means for controlling the temperature of the product adhering to the inside of the substrate to be processed or the inside of the processing vessel within a predetermined range.

Further, the present invention is particularly effective when cleaning the inside of the processing container of an apparatus having a substrate holding means in the processing container and capable of forming a silicon nitride film on the substrate to be processed. .

Further, it is desirable to use a vacuum pump as an exhaust means capable of holding the processing vessel at a pressure of 100 Pa or less.

Further, it is desirable to provide a porous rectifying plate for uniformly supplying the ClF ₃ gas and the NO gas onto the processing substrate.

Further, by providing a mechanism for rotating the substrate holding means together with the substrate to be processed,
More uniform etching becomes possible.

The operation of the present invention will be described as follows. That is, when etching silicon nitride with ClF ₃ gas, it is considered that silicon (Si) atoms are gasified as SiF ₄ having a high vapor pressure, and remaining nitrogen (N) atoms are desorbed as N 2 gas. At this time,
It is the desorption of N atoms that controls the etching rate.
It is considered that the etching rate of silicon nitride is much lower than the etching rate of silicon alone due to the difficulty in removing atoms.

On the other hand, in the present invention, ClF
By supplying NO gas with _3, elimination previous N atoms remaining on the surface, N ₂ O or N ₂ + 1 / 2O ₂
Thus, the removal of N atoms is promoted, and a high etching rate can be obtained.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a principal part conceptually showing a substrate processing apparatus according to a first embodiment of the present invention.

The apparatus shown in the figure is a single-wafer-type vapor phase growth apparatus for forming a thin film on the surface of a semiconductor wafer. By using the etching method of the present invention, it is possible to remove deposits deposited in the processing vessel. The feature is that cleaning can be performed quickly and reliably.

That is, when a silicon nitride film is formed on the surface of a semiconductor wafer by a vapor phase growth method, the silicon nitride film is formed on a portion other than the surface of the semiconductor wafer as a substrate to be processed, for example, on the surface of a holder holding the semiconductor wafer or the inner wall surface of the processing vessel. Nitride adheres. The attached silicon nitride contaminates the surface of the semiconductor wafer as particles, lowering the yield of semiconductor devices as products, and changing the heat dissipation conditions of the semiconductor wafer to worsen the temperature distribution, thereby causing inconvenience in substrate processing. It may cause it to occur. Therefore, by introducing a mixed gas of ClF ₃ gas and NO gas into the processing container after film formation by the vapor phase growth method, silicon nitride attached to the holder surface or the processing container inner wall surface can be quickly removed, Thereby, good substrate processing is maintained.

A processing chamber 2 is formed in the processing container 1. The processing container 1 has a structure capable of maintaining airtightness, and is connected to an exhaust pump (not shown) through an exhaust pipe 3. Between the processing chamber 2 and the upper wall of the processing chamber 1, a rectifying plate 4 having a large number of holes formed in a plate made of quartz or the like is arranged in parallel with the processing substrate. A space 5 formed between the current plate 4 and the upper wall of the processing container 1 is connected to a gas supply device (not shown) through gas inlets 6 and 7.

At a central position in the processing chamber 2, a holder 9 for holding a semiconductor wafer 8 as a substrate to be processed in a position parallel to the rectifying plate 4 is rotatably arranged. The lower end of the holder 9 is held by a bearing provided with a seal mechanism for maintaining airtightness, and is rotatable by a rotation drive device 11. Inside the holder 9, an electric heater 1 for heating a semiconductor wafer 8 supported by the holder 9 from below is provided.
0 is disposed, and the electric heater 10 is connected to the power supply device 12 through an electrode penetrating the lower wall of the processing container 1 while maintaining airtightness and insulation. Further, the power supply device 12
Can be controlled by a thermocouple 13 fixed in the vicinity of an electric heater 10 or an output signal of a radiation thermometer 14 for measuring the temperature of the holder 9, whereby the holder 9 and the semiconductor wafer held by the holder 9 can be controlled. 8 is controlled and maintained at a predetermined temperature.

Various gases such as NO gas introduced through the gas inlets 6 and 7 act on the processing chamber 2 for depositing and etching a thin film, and then the exhaust pipe 3
And exhausted by an exhaust gas treatment device (not shown).

Hereinafter, an example of a procedure for cleaning the inside of the processing chamber 2 by the substrate processing apparatus configured as described above will be described.

FIG. 2 is a flowchart illustrating a series of vapor phase growth steps including a procedure for cleaning the inside of the processing chamber in the present embodiment. The flowchart shown in the figure is roughly divided into a step 200 for depositing a thin film on a wafer and a step 300 for cleaning the processing chamber.

First, as shown as step 202 in FIG. 2, the processing chamber 2 is opened using an exhaust pump (not shown).
Is exhausted to 100 Pa or less. By this operation, oxygen (O ₂ ) in the processing chamber 2 is exhausted, and the semiconductor wafer 8 and the holder 9 can be prevented from being oxidized even during heating using the electric heater 10. Next, in step 204, the processing chamber 2 is maintained at a predetermined pressure, for example, 6666 Pa, by controlling the exhaust amount while introducing a fixed amount of inert gas, for example, argon (Ar) gas through the gas inlet 6. Next, in step 206, power is supplied to the electric heater 10 while controlling using the power supply device 12, and the semiconductor wafer 8 is maintained at a predetermined temperature, for example, 1000 ° C. Further, in step 210, a mixed gas of a source gas containing silicon and nitrogen atoms and a carrier gas, for example, dichlorosilane, is introduced into the processing chamber 2 from the gas inlet 6 through the space 5 so that the above-mentioned pressure relationship is maintained. (SiH ₂ Cl ₂ )
, Ammonia (NH ₃ ), and argon (Ar) are supplied to form a silicon nitride film.

When the film formation is completed, the supply of all the source gases is stopped, and the wafer 8 is unloaded from the processing chamber 2 in step 212. Then, if necessary, in step 208, the next wafer 8 is carried into the processing chamber 2 and placed on the holder 9. Then, in step 210, a predetermined thin film is formed again.
Remove from

When the formation of a thin film such as a silicon nitride film on one or more specified number of semiconductor wafers 8 is completed as described above, the film forming process is completed as shown in step 214.

Next, the process chamber cleaning step 300 is started.

First, in step 302, the processing chamber 2 is evacuated again to 100 Pa or less using an exhaust pump (not shown). By this operation, the source gas remaining in the processing chamber 2 is removed, and the reaction between the ClF ₃ gas to be supplied next and the source gas can be suppressed.

Next, in step 304, the amount of exhaust gas is controlled while introducing a predetermined amount of an inert gas, for example, argon gas into the processing chamber 2 again through the gas inlet 6, and the processing chamber 2 is set to a predetermined pressure. For example, it is kept at 2666 Pa.

Further, in step 306, the holder 9 is heated by the electric heater 10 and the power supply device 12 connected thereto, and is controlled to a predetermined temperature in the range of 100 ° C. to 400 ° C., for example, 250 ° C.

Next, in step 308, cleaning is performed. Specifically, C is introduced into the processing chamber 2 from the gas inlet 7 through the space 5 so that the above-mentioned pressure relationship is maintained.
By supplying the IF ₃ gas and the NO gas while controlling them at predetermined flow rates, the holder 9 and the inner wall of the processing chamber 2 can be cleaned at high speed. Here, in FIG. 2, ClF ₃ gas is introduced in step 308a,
The case where NO gas is introduced in step 308b has been exemplified. However, the present invention is not limited to this. That is, the order of supplying these gases may be reversed, or they may be supplied simultaneously.

After a predetermined time has elapsed and the deposits inside the processing chamber 2 have been removed, the cleaning is terminated in step 310.

FIG. 3 shows the case where the above-described substrate processing apparatus is used and NO
FIG. 9 is a graph showing an Arrhenius-type plot of experimental results obtained by measuring the etching rates of silicon and silicon nitride under the condition where no gas is supplied.

As can be seen from the figure, a result that the etching rate of silicon nitride is nearly two orders of magnitude lower than the etching rate of silicon over the entire experimental range. When etching silicon and silicon nitride with ClF ₃ gas, etching proceeds as Si atoms are gasified as SiF ₄ having a high vapor pressure. further,
In the case of silicon nitride, it is considered that the remaining N atoms are desorbed as N _2. At this time, it is the desorption of N atoms that controls the etching rate. It is considered that the etching rate of silicon nitride is much lower than that of silicon alone.

FIG. 4 is a graph showing experimental values of an etching rate obtained when a silicon nitride film is etched by adding a NO gas to a ClF ₃ gas.

Here, the total pressure of the etching atmosphere is set to 66.
66 Pa, the partial pressure of ClF ₃ gas was maintained at 3333 Pa, and the etching temperature was maintained at 250 ° C., respectively. From FIG. 4, it can be seen that the etching rate of the silicon nitride increases as the amount of addition of the NO gas increases, and the partial pressure of the NO gas becomes about 10%.
It can be seen that at 00 Pa, the etching rate increases to nearly four times.

That is, according to the present invention, by supplying NO gas simultaneously with ClF ₃ , N atoms remaining on the surface before desorption are extracted in the form of N ₂ O or N ₂ + 1 / 2O ₂ , By promoting the removal of atoms, high-speed etching can be performed.

Further, according to the present invention, since plasma is not required, a complicated and expensive plasma generator is not required, and the present invention is widely applied to a conventional vapor phase growth apparatus which does not use plasma, thereby ensuring cleaning. The effect that it can be obtained is also obtained.

Further, according to the present invention, the apparatus cost is reduced. That is, in order to perform plasma etching by the conventional method, expensive additional equipment such as a microwave power supply, a microwave matching device, a microwave reactor, and a radical transport tube is newly required in addition to a normal device. . Further, metals such as SUS cannot be used in a reaction furnace for etching (or for forming a SiN film), and surface treatment such as using an expensive aluminum chamber or applying a Teflon coat to the inner surface is required. Therefore, the extra cost for the apparatus has to be considerably larger than the cost of the entire apparatus. On the other hand, according to the present invention, the configuration of the device is simple, and the cost can be significantly reduced.

According to the present invention, the degree of freedom of the device is increased. That is, when the purpose is to clean the film forming apparatus, the shape (or material) of the apparatus should be optimized for the film formation. However, when plasma cleaning is used, optimization for radical transport is also performed at the same time. I have to. Therefore, optimization for film formation is greatly restricted, and the degree of freedom in apparatus design is also greatly limited.

For example, when a rectifying plate for uniformly supplying a source gas for film formation is provided, from the viewpoint of radical supply, the material of the rectifying plate is limited to a material such as Teflon, alumina or quartz. I will. When Teflon is used, it may be difficult to sufficiently raise the temperature of the substrate during film formation due to the limitation of the heat-resistant temperature of Teflon. In addition, when alumina or quartz is used, when it is necessary to cool the current plate in order to prevent the current plate from being contaminated during film formation, the cooling may be extremely difficult. In contrast, according to the present invention, these restrictions are not required, and the degree of freedom of the device is improved.

Further, according to the present invention, the pressure change can be small. That is, in the case of etching using plasma, the pressure of the gas phase (total pressure) needs to be kept at a low pressure of about 100 Pa or less. This is for the purpose of efficiently performing ionization at the time of plasma generation and ensuring the lifetime of generated radicals.

On the other hand, when a film is formed by a method such as thermal CVD, the film forming speed is often determined by the pressure of the source gas. Therefore, when high-speed film formation is required in a single-wafer type film formation apparatus or the like, the total pressure of the gas phase is set to a pressure of about 1,000 to 10,000 Pa.

This indicates that there is a great difference between the pressure at the time of film formation and the pressure at the time of cleaning, and a large amount of particles may be wound up in the process of pressure adjustment. Particles remaining in downstream pipes and the like are wound up when the pressure increases after cleaning and reach the substrate, which can be a major cause of abnormal growth during film formation and poor device conduction.

On the other hand, in the cleaning with ClF ₃ / NO according to the present invention, it is very easy to keep the film forming pressure and the cleaning pressure the same.

Further, according to the present invention, the inside of the metal pipe can be cleaned. That is, when a film of Si ₃ N ₄ is formed by thermal CVD using SiH ₄ / NH ₃ as a source gas, Si powder may accumulate on a low-temperature portion such as a cooled chamber inner wall or a downstream pipe. In the case of plasma cleaning, all radicals are deactivated on the surface of a pipe usually made of a metal such as SUS. Therefore, it is practically impossible to clean the downstream piping.

[0055] However, when using ClF _3, the ClF ₃ to the downstream metal pipes reached, readily react with powder deposited Si. Therefore, when silicon powder accumulates in a low-temperature portion such as a downstream pipe, cleaning including the downstream pipe can be performed.

Next, a second embodiment of the present invention will be described.

In this embodiment, an etching method and an apparatus for etching silicon nitride or the like formed on a semiconductor wafer or the like at a high speed will be described.

FIG. 5 is a sectional view showing a main part of a substrate processing apparatus according to a second embodiment of the present invention. That is, the apparatus illustrated in FIG. 1 is a single wafer type etching apparatus for etching the surface of a semiconductor wafer. In FIG. 5, the same portions as those in FIG. 1 are denoted by the same reference numerals, and detailed description of the overlapping portions will be omitted.

In the apparatus according to this example, only an inert gas, for example, an argon gas is supplied from the gas inlet 6, and there is no gas supply system for supplying a source gas for depositing a thin film. That is, it is configured as a single-wafer etching apparatus having no vapor phase growth means as in the first embodiment.

The radiation thermometer 14 directly measures the temperature of the semiconductor wafer 8 and controls the semiconductor wafer 8 to be maintained at a predetermined temperature. By supplying ClF ₃ gas and NO gas to the processing chamber 2 from the gas inlet 7 through the space 5 while controlling the flow rates at predetermined rates, the silicon nitride film previously formed on the semiconductor wafer 8 is formed. A layer such as an object can be etched at a high speed.

The procedure of this etching can be substantially the same as that illustrated as the step 300 in FIG. Also in the present embodiment, by supplying the ClF ₃ gas and the NO gas, it is possible to etch the silicon nitride at a higher speed than before. In addition, since no plasma is used, the problem that the semiconductor wafer is damaged by the plasma can be solved. Further, since plasma is not required, the degree of freedom of etching conditions such as pressure during etching is greatly expanded. Further, since no plasma is required, the configuration of the apparatus is simplified, and the cost can be significantly reduced.

Next, a third embodiment of the present invention will be described.

FIG. 6 is a sectional view showing a main part of a substrate processing apparatus according to a third embodiment of the present invention.

That is, the apparatus illustrated in the figure is a batch type vapor phase growth apparatus for forming various thin films such as silicon nitride on the surface of a semiconductor wafer. In such a batch-type apparatus, silicon nitride adheres to the surface of the susceptor holding the semiconductor wafer or the inner wall surface of the processing container similarly to the single-wafer-type apparatus, and in addition to lowering the yield of the semiconductor device as particles, This may cause inconvenience in substrate processing, such as changing the heat radiation condition of the semiconductor wafer to deteriorate the temperature distribution. Therefore, as in the first embodiment described above, the present invention is effective for a batch type apparatus.

In the figure, reference numeral 21 denotes a transparent material that transmits infrared light;
For example, a processing container made of quartz is shown.
A processing chamber 22 is formed therein. The processing container 21 has a structure capable of maintaining airtightness, and is connected to an exhaust pump (not shown) through an exhaust pipe 23. A large number of semiconductor wafers 26, which are substrates to be processed, are introduced into the processing chamber 22 in parallel on a susceptor 27 made of a material that transmits infrared light, for example, quartz. An infrared lamp 28 for heating the semiconductor wafer 26 is disposed outside the processing container 21, and the semiconductor wafer 26 is heated to a predetermined temperature and maintained. Many semiconductor wafers 26
In order to control the temperature of the infrared lamps, the infrared lamps 28 may be a plurality of lamp groups each capable of independently controlling the output. A semiconductor wafer 2 is supplied by supplying a source gas, for example, dichlorosilane and ammonia gas, from a gas supply device (not shown) through a gas inlet 24 while controlling the flow rate.
6 can be formed with silicon nitride.

Also in this embodiment, the processing chamber 22 can be cleaned in substantially the same manner as the procedure illustrated in FIG. That is, after completion of the predetermined film forming process, the semiconductor wafer 26 is entirely removed, and only the ClF ₃ gas and the NO gas are supplied through the introduction port 25 while heating and controlling the temperature again, so that the surface of the susceptor 27 and the inner wall of the processing container 21 are attached. Silicon nitride can be quickly cleaned.

According to the present invention, it is not necessary to add a plasma generator to the batch type vapor phase growth apparatus as shown in FIG. 6, and it is possible to efficiently and easily clean every corner of the processing chamber 22. .

The embodiments of the present invention have been described with reference to the examples.

However, the present invention is not limited to these specific examples. That is, the cleaning method of the present invention can be similarly applied to all conventional vapor phase growth apparatuses, etching apparatuses, and the like, and can obtain the same effects. At this time, conditions such as the pressure of the atmosphere, the flow rate of the gas, and the temperature can be appropriately optimized. further,
Other gases may be mixed in addition to the ClF ₃ gas and the NO gas.

[0070]

The present invention is embodied in the form described above, and has the following effects.

First, according to the present invention, it is possible to perform plasma-less, low-cost, high-speed etching and cleaning of silicon nitride by adding NO gas. This is effective for in-situ (in-situ) cleaning of a thin film forming apparatus for forming a film.

In particular, when the present invention is applied to the cleaning of a substrate processing apparatus, it is excellent in that it can reliably and easily clean every corner of the processing chamber as compared with the case where conventional plasma is used. . As a result, problems such as generation of particles, abnormal growth, and cross contamination caused by residues such as “flakes” deposited on the inner wall of the processing chamber can be reliably and easily eliminated. That is, according to the present invention, it is possible to widely apply the cleaning method with a much simpler structure as compared with the conventional cleaning method using plasma, and to obtain a special effect.

When the present invention is applied to a method of etching a thin film on a substrate such as a semiconductor wafer, silicon nitride can be efficiently and easily etched while preventing damage by plasma. With the recent high integration and miniaturization of semiconductor integrated circuits, semiconductor elements formed on a semiconductor wafer are easily damaged by charged particles such as plasma during the manufacturing process. In addition, since plasma is not required in the etching step, damage to semiconductor elements can be eliminated, reliability of various semiconductor devices can be improved, and manufacturing yield can be improved.

As described above, according to the present invention, it is possible to efficiently and easily perform etching or cleaning of silicon nitride without using plasma, and industrial merit is great. is there.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a main part of a substrate processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating a series of vapor phase growth steps including a procedure for cleaning the inside of a processing chamber in the present invention.

3 is a graph showing an Arrhenius-type plot of experimental results obtained by measuring the etching rates of silicon and silicon nitride using the substrate processing apparatus of FIG. 1 without supplying NO gas.

FIG. 4 is a graph showing experimental values of an etching rate obtained when a silicon nitride film is etched by adding a NO gas to a ClF ₃ gas.

FIG. 5 is a sectional view of a main part showing a substrate processing apparatus according to a second embodiment of the present invention.

FIG. 6 is a sectional view showing a main part of a substrate processing apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

 1,21 processing container 2,22 processing chamber 3,23 exhaust pipe 6,7,24,25 gas inlet 8,26 semiconductor wafer

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4K030 DA01 4K057 DA01 DA20 DB06 DB08 DB20 DD07 DE01 DE06 DE20 DG06 DG12 DG14 DM01 DN10 5F004 AA13 AA15 AA16 BA01 BA04 BA11 BB18 BB19 BB29 BB30 BD07 CA01 CA09 DA00 DB01 DB07 DB08 DB17 DB18 FA01 FA08 5F045 AB02 AB03 AB33 AB40 AC02 AC03 AC18 AD05 AD06 AD07 AE02 AE03 AE05 AE07 AE09 AE11 AE13 AE15 AE17 AE19 AE21 AE23 AE25 BB03 BB08 BB15 DP01 DP02 DP03 DP13 DP19 D0503 EB03 EK08 EB03 EK08

Claims (3)

[Claims] 1. A process vessel containing ClF ₃ gas and NO
An etching method, comprising supplying a gas and etching a surface of a substrate to be processed placed inside the processing container or a product attached to the inside of the processing container. 2. A processing container, and gas supply means for supplying ClF ₃ gas and NO gas into the processing container, wherein the N gas is supplied together with the ClF ₃ gas into the processing container.
A substrate processing apparatus, characterized in that an O gas is supplied to etch a surface of a substrate to be processed placed inside the processing container or a product attached to the inside of the processing container. 3. The apparatus according to claim 2, further comprising temperature control means for controlling the temperature of the product adhered to the inside of the substrate to be processed or the inside of the processing vessel within a predetermined range.
The substrate processing apparatus according to any one of the preceding claims.