JP2924596B2 - Low temperature dry etching method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-temperature dry etching method and apparatus for dry-etching the surface of a material to be etched while keeping the material to be etched at a low temperature.

[0002]

2. Description of the Related Art Recently, as a method of dry-etching an oxide film or a metal film with good verticality, the temperature of a material to be etched is set to 0 ° C.
The so-called low-temperature dry etching technique, which holds and controls the following low temperature and suppresses the radical reaction on the side while maintaining the etching rate in the depth direction by the ion assist effect, has attracted attention.

FIG. 6 shows a schematic configuration diagram of a low-temperature dry etching apparatus used for study by the present inventors. It comprises a reaction chamber 1 for performing etching and a preparatory chamber 2 for inserting and removing a material to be etched.

First, a material to be etched (quartz glass sample) 10 to be etched is a sample insertion / sample removal system 1.
2 to the preparatory chamber 2. Thereafter, the preliminary chamber 2 is evacuated by the exhaust system 4. On the other hand, the inside of the reaction chamber 1 is maintained at a high vacuum by the exhaust system 3 so as to receive the sample 10 from the preliminary chamber 2. Also, the lower electrode 5-2 for mounting the sample 10 is configured to keep the sample 10 at a low temperature of 0 ° C. or less by flowing a coolant in the electrode as indicated by arrows 9-1 to 9-2. It is.

Next, the preparatory chamber 2 is set to a desired degree of vacuum (13.3 ×
When the pressure reaches 10 ^{−2 to} 13.3 × 10 ⁻³ Pa), the airtight valve (gate valve) 11 is opened, and the sample 10 is transferred from the preliminary chamber 2 onto the lower electrode 5-2 of the reaction chamber 1. It is placed on the electrode 5-2. Next, He is sprayed on the back surface of the sample 10 in the direction of the arrow of the He gas introduction system 8 to accelerate the temperature reduction of the sample 10.

After that, the upper electrode 5-1 and the lower electrode 5-2
To generate a plasma by applying a high-frequency power source 6 between
This is a method in which etching is performed while flowing an etching gas (in this case, a CHF ₃ gas is used to etch quartz-based glass) in the plasma atmosphere.

In this method, it is known that the quartz glass film can be etched with good verticality by using the WSi film as a mask by keeping the temperature of the sample 10 at a lower temperature (-40 ° C. or lower). .

[0008]

However, it has been found that the low-temperature dry etching method using the low-temperature dry etching apparatus for examination in which only a preliminary chamber is provided in the reaction chamber has the following problems.

(1) When the material to be etched is transferred from the preparatory chamber to the reaction chamber, water vapor attached to the material to be etched is condensed and dew condensation easily occurs. It turned out to be difficult to progress. Further, a phenomenon that the etched surface became cloudy occurred.

(2) After the etching is completed, the material to be etched is inserted from the reaction chamber through the preliminary chamber.
It was found that when the material to be etched was taken out of the material to be etched into the atmosphere, dew condensation occurred on the surface of the material to be etched. Therefore, when the material to be etched is transferred to the next step (for example, a step of removing the WSi film on the surface of the material to be etched),
Extra work was needed to eliminate condensation.

(3) Every time the material to be etched is etched, deviations in characteristics such as an etching rate and verticality of a side surface occur, and there is a problem in reproducibility.

(4) Since there is only one reaction chamber, the material to be etched must be once taken out to the atmosphere in order to etch two or more films having different etching conditions.
For this reason, pattern defects have occurred due to the attachment of dust and impurities.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, to prevent the formation of dew on the surface of the material to be etched when the material to be etched is inserted into the reaction chamber and when the material is taken out to the outside. An object of the present invention is to provide a low-temperature dry etching method for performing etching with good reproducibility, and a low-temperature dry etching apparatus that can be realized by a simple configuration.

[0014]

According to a first aspect of the present invention, a material to be etched inserted into a preliminary chamber is conveyed to a reaction chamber via an airtight valve, and the material to be etched is kept at a low temperature of 0 ° C. or lower in the reaction chamber. In the method of low-temperature dry etching, after the material to be etched is inserted into the preliminary chamber, and after the material to be etched is transported from the reaction chamber to the preliminary chamber, a gas having a dew point of −60 ° C. or less is introduced into the preliminary chamber. while it is flowing,
This is a low-temperature dry etching method in which the preliminary chamber is evacuated by an exhaust system and dried under vacuum. The reason why the gas having a dew point of −60 ° C. or less is that dew condensation cannot be effectively prevented if the temperature is higher than −60 ° C.

According to a second aspect of the present invention, there is provided a low-temperature dry etching method according to the first aspect, wherein when the vacuum drying is performed while flowing the gas into the preliminary chamber, the drying is further performed by heating.

According to a third aspect of the present invention, there is provided a low-temperature dry etching method according to the first or second aspect, wherein at least two reaction chambers are connected by an airtight valve and dry-etch the material to be etched. It is possible to carry out the material to be etched through the hermetic valve to each reaction chamber without taking out the material into the atmosphere,
This is a low-temperature dry etching method characterized by continuously performing dry etching according to the function of each reaction chamber.

A fourth invention is the low-temperature dry etching method according to the third invention, wherein the material to be etched is transported into each reaction chamber via a preliminary chamber.

According to a fifth aspect of the present invention, there is provided a preparatory chamber having a mechanism for evacuating while flowing a gas for preventing dew condensation on a material to be etched, and at least one reaction connected to the preparatory chamber via an airtight valve. And a transfer mechanism for inserting / removing the material to be etched into / from the preliminary chamber and transferring the material between the preliminary chamber and the reaction chamber. Is a low-temperature dry etching apparatus characterized by having a mechanism for dry-etching a material to be etched by flowing water and having a mechanism for etching at least one of the reaction chambers at a low temperature of 0 ° C. or lower.

A sixth invention is the low-temperature dry etching apparatus according to the fifth invention, wherein a heating mechanism is provided in the preliminary chamber.

[0020]

According to the first aspect of the invention, after the material to be etched is inserted into the preliminary chamber, and after the material to be etched is transported from the reaction chamber to the preliminary chamber, the dew point is maintained at -60 ° C. or lower in the preliminary chamber. Vacuum drying is performed while flowing gas, so water vapor on the surface of the material to be etched is effectively removed,
No dew condensation occurs on the surface of the material to be etched. Also,
The surface etched in the reaction chamber does not become cloudy. Thereby, characteristics such as an etching rate and verticality of a side surface can be obtained with good reproducibility.

In particular, as in the second invention, when evacuation is performed while flowing gas, if the preparatory chamber is further heated and dried by heating, the removal of water vapor on the surface of the material to be etched becomes more effective, and Not at all.

According to the third aspect, since the material to be etched having at least two types of films (for example, a metal film and an oxide film) can be continuously dry-etched without being exposed to the atmosphere, There is almost no occurrence of pattern defects due to attachment of dust and impurities. Naturally, no dew condensation occurs on the surface of the material to be etched. A specific example of the third invention will be described with reference to a waveguide substrate. First, in a reaction chamber for performing dry etching at room temperature, WSi on a substrate is formed using a photoresist pattern as a mask.
After dry etching of the film, the photoresist pattern is subsequently stripped off in the same reaction chamber. After the separation, the glass (eg, a SiO ₂ -based film) can be dry-etched at a low temperature by being transferred to another reaction chamber capable of low-temperature dry etching.

According to the fourth aspect, since the material to be etched is always sent to the reaction chamber via the preliminary chamber, no dew condensation occurs.

According to the fifth aspect of the present invention, dry etching can be performed without causing dew condensation on the surface of the material to be etched by adding a simple dew condensation preventing mechanism for evacuating and exhausting gas while flowing gas into the preliminary chamber. It is also possible to provide a low-temperature dry etching apparatus which does not cause dew condensation even when the material to be etched is taken out.

In particular, as in the sixth aspect of the present invention, a simple structure in which a heating mechanism is added to the preliminary chamber can more effectively prevent dew condensation on the surface of the material to be etched.

[0026]

FIG. 1 shows a first embodiment of a low-temperature dry etching apparatus for carrying out the method of the present invention. Here, a waveguide sample was used as a material to be etched.

This apparatus comprises two reaction chambers 1-1 and 1-2 for performing dry etching, evacuation systems 3-1 and 3-2 for evacuating the respective reaction chambers, and a vacuum before transporting to each reaction chamber. A preparatory chamber 2 for creating a state, an exhaust system 4 for evacuating the preparatory chamber 2, a gate valve 11-1 connecting one reaction chamber 1-1 to the preparatory chamber 2, and a reaction chamber 1-2 and a preparatory chamber 2 for the other. , A gas supply system 14 for supplying an etching gas (NF ₃ , CF ₄ , Ar, etc.) into one reaction chamber 1-1, and an etching gas (CHF) into the other reaction chamber 1-2. ₃ , a gas supply system 7 for supplying Ar, etc.).

A high-frequency power supply 6-1 is applied between an upper electrode 13-1 provided in one reaction chamber 1-1 and a lower electrode 13-2 on which the sample 10 is mounted, and the other reaction chamber 1-2 is provided.
The high frequency power supply 6-2 applied between the upper electrode 5-1 installed in the inside and the lower electrode 5-2 on which the sample 10 is mounted, and the sample 10 on the lower electrode 5-2 in the other reaction chamber 1-2 are In order to cool to a low temperature, there is provided a refrigerant circulation system 9 for flowing a refrigerant in a direction indicated by arrows 9-1 to 9-2. As can be seen from the illustrated example, all of the reaction chambers of this embodiment constitute a parallel plate reactive ion etching apparatus. The other reaction chamber 1-2 provided with the circulation system 9 is used for low-temperature dry etching.

Further, the sample 10 in the other reaction chamber 1-2 is
He gas introduction system 8 for blowing He gas to the back surface of sample 10 to efficiently maintain the temperature of sample 10 at a low temperature; sample insertion / removal of sample 10 from preliminary chamber 2
A sample removal system 12, a gas introduction system 15 for introducing gas (N ₂ , Ar, O ₂ , O, He, etc.) into the preparatory chamber 2 to prevent dew condensation. A transfer system for transferring the sample 10 between the reaction chambers 1-1 and 1-2 is provided. The transfer system and the sample insertion / sample removal system 12 constitute a transport mechanism.

Next, a method of performing dry etching using the low-temperature dry etching apparatus will be described with reference to FIG.

First, the sample inserted from the sample insertion / sample removal system 12 in the preliminary chamber 2 will be described with reference to FIG. The sample was a 0.5 mm thick, 3 inch diameter Si substrate. S
Instead of the i-substrate, a semiconductor such as InP or GaAs, quartz-based or multi-component glass, a dielectric, a magnetic material, or the like may be used. In this sample, a buffer layer 20, a core layer 19, and a WSi film 18 are sequentially formed on a substrate 16, and a photoresist pattern 17 is patterned on the WSi film 18. The buffer layer 20 is made of SiO ₂ and has a thickness of about 10 μm. The core layer 19 is formed of a film (about 8 μm thick) in which TiO ₂ (or GeO ₂ ) is added at 1% by weight to SiO ₂ . The WSi film 18 is a core layer 19
Is formed to a thickness of about 1 .mu.m because it becomes a mask material for etching the substrate. Photoresist pattern 1
Reference numeral 7 denotes a mask material for patterning the WSi film 18 by dry etching, and its film thickness is selected to be 0.5 to 1 μm in view of a selectivity.

Now, the sample 10 shown in FIG.
After being inserted into the preparatory chamber 2 shown in FIG. 5, the N ₂ gas having a dew point of −60 ° C. or less (or a gas such as Ar, He, O _2, etc.) may be introduced into the preparatory chamber 2 from the direction of the arrow of the gas introduction system 15. While the gas is flowing (gas flow rate of 100 SCCM), the interior of the preliminary chamber 2 is evacuated and dried by the exhaust system 4. At the same time, the two reaction chambers 1-1 and 1-2 are also evacuated by the exhaust systems 3-1 and 3-2. Vacuum evacuation is performed while flowing N ₂ gas having a dew point of −60 ° C. or less into the preliminary chamber 2, thereby removing water vapor adhering to the sample 10. Here, the degree of vacuum in the preliminary chamber 2 and the reaction chambers 1-1 and 1-2 is maintained at 1.33 × 10 ⁻² Pa or less.

After removing the water vapor adhering to the sample 10 by using both N ₂ gas and vacuum exhaust, one of the reaction chambers 1-1 was used.
Samples 10 to open the Ruge Tobarubu 11-1 connected to and carried from the pre-chamber 2 into the reaction chamber 1-1, is placed on the lower electrode 13-2. Next, the gate valve 11-1 is closed, and the high frequency power supply 6 is connected between the upper electrode 13-1 and the lower electrode 13-2.
1 is applied to generate plasma between the electrodes 13-1 and 13-2, and NF ₃ gas is flowed in the plasma atmosphere from the gas supply system 14 in the direction of the arrow. Reaction chamber 1-1 at this time
The degree of vacuum inside was set to 7.98 Pa. The NF ₃ gas flow rate was kept at 13 SCCM, and the high frequency power was 20 W. As a result, the etching of the WSi film 18 was completed in about 6 minutes. The sample in this state is shown in FIG. This etching is not performed at a low temperature.

Then, the etching gas supplied from the gas supply system 14 was switched from NF ₃ gas to CF ₄ gas, and etching was similarly performed in a plasma atmosphere to remove the photoresist pattern film 17 on the surface (in this state). Is not shown in FIG. 2). Thereafter, the gas supply system 14 was closed to stop the supply of the CF ₄ gas, the high-frequency power supply 6-1 was turned off, the gate valve 11-1 was opened, and the sample 10 was sent back into the preliminary chamber 2 by the transfer system. Then, high vacuum evacuation was performed again while flowing N ₂ gas at 100 SCCM into the preliminary chamber 2.

Next, the lower electrode 5 in the other reaction chamber 1-2 is
The refrigerant flows from the circulating system 9 in the direction indicated by arrows 9-1 to 9-2 in FIG. 2 and exhausts while controlling the lower electrode 5-2 at a low temperature (any value in the range of 0 ° C. to −100 ° C.). The sample 10 was transferred into the reaction chamber 1-2 evacuated by the system 3-2. That is, the gate valve 11- connected to the other reaction chamber 1-2.
2, the lower electrode 5-2 of the reaction chamber 1-2 is opened from the preliminary chamber 2.
Transport the sample on top. After the sample 10 was placed on the lower electrode 5-2, 5 SCCM of He gas was sprayed on the back surface of the sample 10 from the direction of the arrow of the He gas introduction system 8 to further promote the lowering of the temperature of the sample 10. This He gas is sample 1
0 and the lower electrode 5-2 leak, and the reaction chamber 1-2
It leaked inside.

In this manner, the sample 10 is maintained at a desired low temperature (-40 ° C. in this embodiment), and the high-frequency power source 6-2 is applied between the upper electrode 5-1 and the lower electrode 5-2 while evacuating. A low-temperature dry etching of the core layer 19 was performed by generating plasma and flowing 15 SCCM of CHF ₃ gas from the gas supply system 7 in the direction of the arrow. The degree of vacuum at this time is 1.33P
a, RF power was 300 W, and etching was performed for about 80 minutes. As a result, as shown in FIG. 2C, the core layer 19 was etched in a rectangular shape with good verticality using the WSi film 18 as a mask.

After completion of the etching in the reaction chamber 1-2, the gas supply system 7 is closed to stop the CHF ₃ gas, the high frequency power is turned off, the gate valve 11-2 is opened, and the sample 10
_{The two} gases were transferred into the preliminary chamber 2 evacuated while flowing at 100 SCCM. After transfer, gate valve 11-2
Was closed, and the sample 10 was kept in the preliminary chamber 2 for about 30 minutes.
This is because water vapor on the surface of the sample 10 is effectively removed.

Thereafter, the gate valve 11-1 connected to the one reaction chamber 1-1 was opened again, and the sample 10 was placed from the preliminary chamber 2 on the lower electrode 13-2 of the reaction chamber 1-1. Then, the NF ₃ gas is flowed from the direction of the arrow of the gas supply system 14, and while applying a high frequency power (20 W) between the upper electrode 13-1 and the lower electrode 13-2, the core is maintained at a vacuum degree of 7.98 Pa. The WSi film 18 on the pattern 19 was removed by dry etching. Then, the structure shown in FIG. 2D was obtained.

Thereafter, the gas supply system 14 is closed to stop the NF ₃ gas, the high frequency power is turned off, and the gate valve 11-1 is turned off.
Was opened and the sample 10 was transported into the preliminary chamber 2. Then, after the evacuation while flowing while dew point -60 ° C. in N ₂ gas, stop the evacuation of the preliminary chamber 2, the pre-chamber 2 continues performing the introduction of N ₂ gas with N ₂ gas The sample was filled, the vacuum in the preliminary chamber 2 was released, and the sample 10 was taken out to the atmosphere.
From the obtained sample, it was found that the side surface of the core layer 19 was etched at an angle of about 90 ° with good perpendicularity.
Also, the side surface of the core layer 19 was extremely small, less than 50 Å (peak value). Further, even when the sample was taken out of the preliminary chamber 2 into the atmosphere, no dew condensation occurred on the sample surface. The above prototype was repeated six times, but the variation in the etching rate of the core layer 19 and the roughness of the side surface was 5%.
%. It was also found that the above-mentioned variation in the surface of the sample having a diameter of 3 inches was within 3%.

FIG. 3 shows a second embodiment of the low-temperature dry etching apparatus according to the present invention. This is spare room 2
A heating source 21 for heating the preliminary chamber 2 is added to the inside, and when the sample 10 is put in the preliminary chamber 2 and evacuated while flowing gas (Ar in this case) from the gas introduction system 15, the heating source 21 is used. At 21, the sample 10 is heated. The temperature of the heating source 21 is preferably in the range of 20 ° C. to 500 ° C. in order to effectively remove water vapor. By evacuating by flowing a gas while heating as described above, the sample 10
Water vapor on the surface can be more efficiently removed, and adhesion of water vapor on the surface of the sample 10 can be effectively prevented. Further, this heating is also an effective means for vaporizing and removing impurities (for example, organic substances such as an oil film) on the surface of the sample 10.

FIG. 4 shows a simplified third embodiment of the low-temperature dry etching apparatus of the present invention. This is a low-temperature dry etching apparatus in which only one reaction chamber capable of low-temperature dry etching is connected to the preliminary chamber 2. That is, the apparatus performs the low-temperature dry etching process of FIG.

FIG. 5 shows a low-temperature dry etching apparatus according to a fourth embodiment of the present invention in which a heating source 21 is added to the preliminary chamber 2 of the embodiment shown in FIG.

As described above, according to the present embodiment,
The following effects are obtained.

(1) Since water vapor adhering to the sample surface is removed in the preparatory chamber, even if the sample is transferred from the preparatory chamber to the reaction chamber, no dew condensation occurs on the sample. The progress of the etching is not hindered. Also, the clouding phenomenon on the etched surface due to the condensation does not occur.

(2) After the etching is completed, even if the sample is taken out of the reaction chamber through the preparatory chamber into the atmosphere from the sample insertion / sample removal system, water vapor on the sample surface is taken out in the preparatory chamber before taking out. No condensation occurs. Therefore, when transferring the sample to the next step, there is no need for an extra operation for eliminating condensation.

(3) Each time the sample is etched, there is no deviation in characteristics such as the etching rate and the verticality of the side surface, and the reproducibility is good. Therefore, an optical waveguide having excellent characteristics can be obtained.

(4) When there are two or more reaction chambers connected to each other, the material to be etched does not have to be taken out to the atmosphere even when two or more kinds of films having different etching conditions are etched. In addition, it is possible to prevent pattern defects due to adhesion of dust, impurities, and the like.

The present invention is not limited to the above embodiment. First, the number of reaction chambers may be three, or four or more.
Each of these reaction chambers is configured to be connected via a common spare chamber. In each reaction chamber, in addition to an etching gas (NF ₃ , CHF ₃ , CF _4, etc.), a gas such as Ar, N ₂ , He or the like is mixed with the above gas and flowed for efficient removal of water vapor. Or may flow independently.

In the above embodiment, one reaction chamber 1
In the case of -1, normal dry etching for etching a WSi film or the like is performed, but a low-temperature dry etching may be performed by providing a mechanism for keeping the temperature low similarly to the other reaction chamber 1-2.

Also, the sample is not limited to the above-described embodiment, and a material to be etched such as for an optical waveguide or a semiconductor IC can be used. That is, by providing one or two or more reaction chambers, a film to be etched can be a one-layer film, a two-layer film,
Metal, oxide, or a composite film of metal and oxide, which is a layer film, a three-layer film, or a multilayer film can be used.

Further, the reaction chamber is not limited to a parallel plate type reactive ion etching apparatus, but may be another dry etching apparatus.

[0052]

According to the present invention, the following effects can be obtained.

(1) According to the first aspect of the present invention, after the material to be etched is inserted into the preliminary chamber and after the material to be etched is transported from the reaction chamber to the preliminary chamber, the gas is flowed through the preliminary chamber. Since the water vapor on the surface of the material to be etched is effectively removed by vacuum drying, no dew condensation occurs. As a result, a material to be etched can be obtained with good reproducibility without deviations such as etching rate, perpendicularity of the etched side surface, and side surface roughness. Also, the phenomenon that the etched film surface becomes cloudy can be effectively prevented. (2) According to the second aspect of the invention, since heating and drying are further performed, dew condensation on the surface of the material to be etched can be more effectively prevented.

(3) According to the third aspect of the present invention, at least two kinds of films can be continuously etched without exposing them to the air. The occurrence of defects can be prevented. .

(4) According to the fourth aspect of the present invention, every time etching is performed in each reaction chamber, the gas must be passed through the spare chamber, and a gas having a dew point maintained at −60 ° C. or less is flowed through the spare chamber. Since the vacuum drying is performed, dew condensation on the surface of the material to be etched can be effectively prevented.

(5) According to the invention as set forth in claim 5, dry etching can be performed without causing dew condensation on the surface of the material to be etched only by providing the preliminary chamber with a simple drying mechanism of evacuating while flowing gas. And no dew condensation occurs when the material to be etched is taken out.

(6) According to the sixth aspect of the invention, dew condensation on the surface of the material to be etched can be more effectively prevented with a simple configuration in which a heating mechanism is further provided in the preliminary chamber.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a low-temperature dry etching apparatus for performing a low-temperature dry etching method of the present invention.

FIG. 2 is a sectional view of an embodiment of each etching process when the low-temperature dry etching method of the present invention is applied to a waveguide.

FIG. 3 is a schematic configuration diagram showing a second embodiment of a low-temperature dry etching apparatus for performing the low-temperature dry etching method of the present invention.

FIG. 4 is a schematic configuration diagram showing a third embodiment of a low-temperature dry etching apparatus for performing the low-temperature dry etching method of the present invention.

FIG. 5 is a schematic configuration diagram showing a fourth embodiment of a low-temperature dry etching apparatus for performing the low-temperature dry etching method of the present invention.

FIG. 6 is a schematic configuration diagram of a low-temperature dry etching apparatus used for study by the present inventors.

[Explanation of symbols]

 1-1 Reaction chamber 1-2 Reaction chamber 2 Preparatory chamber 3-1 Exhaust system 3-2 Exhaust system 5-1 Upper electrode 5-2 Lower electrode 7 Gas supply system 8 He gas introduction system 9 Refrigerant circulation system 10 Sample 11- DESCRIPTION OF SYMBOLS 1 Gate valve 11-2 Gate valve 12 Sample insertion / sample removal system 13-1 Upper electrode 13-2 Lower electrode 14 Gas supply system 15 Gas introduction system

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-4-251921 (JP, A) JP-A-4-49617 (JP, A) JP-A-4-360527 (JP, A) JP-A-6-360 326056 (JP, A) Japanese Utility Model 1-173932 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) C23F 4/00 H01L 21/3065

Claims (6)

(57) [Claims] 1. A method according to claim 1, wherein the material to be etched inserted into the preliminary chamber is conveyed to a reaction chamber via a hermetic valve, and the material to be etched is kept at a low temperature of 0 ° C. or lower in the reaction chamber. After the material to be etched is inserted into the chamber, and after the material to be etched is transported from the reaction chamber to the preliminary chamber , a vacuum having a dew point of −60 ° C. or less flows into the preliminary chamber while the preliminary chamber is evacuated by an exhaust system. A low-temperature dry etching method characterized by exhausting and drying under vacuum. 2. The low-temperature dry etching method according to claim 1, wherein heating and drying are further performed during vacuum drying while flowing the gas into the preliminary chamber. 3. A method according to claim 1, further comprising at least two reaction chambers connected by an airtight valve for dry-etching the material to be etched.
At least one of the reaction chambers is capable of performing the low-temperature dry etching method according to claim 1 or 2, and transports the material to be etched to each of the reaction chambers via the hermetic valve without taking the material into the atmosphere. A low-temperature dry etching method characterized by continuously performing dry etching according to the function of each reaction chamber. 4. The low-temperature dry etching method according to claim 3, wherein the material to be etched is transported into each reaction chamber via a preliminary chamber. 5. A spare chamber having a mechanism for evacuating while flowing a gas for preventing dew condensation on a material to be etched;
At least one connected to the spare chamber via a hermetic valve
One reaction chamber, and a transfer mechanism for inserting and removing the material to be etched into and out of the preliminary chamber, and transferring the material between the preliminary chamber and the reaction chamber. A low-temperature dry etching apparatus, comprising: a mechanism for dry-etching a material to be etched by flowing an etching gas; and a mechanism for etching at least one of the reaction chambers at a low temperature of 0 ° C. or lower. 6. The low-temperature dry etching apparatus according to claim 5, wherein a heating mechanism is provided in the preliminary chamber.