JP3215081B2 - Apparatus and method for removing exhaust gas from semiconductor manufacturing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for removing exhaust gas generated during the production of semiconductors, liquid crystals and the like.

[0002]

2. Description of the Related Art Recently, in the production of semiconductors, a multi-chamber system having a plurality of chambers is generally employed for CVD because of the need for higher efficiency and higher productivity. In that case, the gas used is a specific gas for deposit, purge, and cleaning depending on the type of process,
Each process changes over time, and it repeats.

Depending on the type of gas used, there is a danger of explosion if the concentration of the deposit gas and the cleaning gas is higher than a certain concentration. Typical example is SiH ₄ / N
F ₃ and SiH ₄ / SF ₆ are known.

Therefore, in order to avoid this danger, the deposit gas and the cleaning gas discharged from the CDV are separately and independently collected regardless of the number of chambers.
It is common to connect a separate abatement machine, that is, two abatement machines, for abatement.

Further, since the cleaning gas is a fluorine-based compound, a special abatement machine is used to avoid corrosion by a fluorine-based gas (eg, F ₂ , HF) generated by thermal decomposition. Often.

[0006] As an extreme case, there is a case in which a detoxifier is connected to each of the CVD chambers in accordance with the number of chambers.

In any case, in the multi-chamber type CVD, a system is adopted in which at least two, and in some cases, more abatement machines are connected to one CVD. Therefore, the equipment cost of the abatement equipment must be large, and the installation area of the abatement equipment also becomes large.

[0008] It is desirable to reduce the installation area of the apparatus in the clean room as much as possible. In particular, since the exhaust gas abatement apparatus is not an apparatus directly involved in the manufacture of products, there is a strong demand for area reduction.

It is also conceivable to install the abatement apparatus outside the clean room in order to reduce the installation area of the apparatus in the clean room. However, it is desirable that the length of the exhaust pipe from the CVD to the abatement apparatus be short,
It needs to be installed near VD. Therefore, there is a problem in that installation outside the clean room requires a long exhaust pipe.

[0010]

The present invention is to challenge you try provide a process aimed at overcoming the problems of the prior art, the corresponding possible in one in the multi-chamber CVD, moreover energy in simple structure
Exhaust gas abatement system with small lug loss and small equipment area, and safe abatement even with small equipment area
Therefore, there is a demand for an exhaust gas abatement method with low energy loss .

[0011]

According to a first aspect of the present invention, there is provided a semiconductor manufacturing exhaust gas abatement apparatus comprising: a plurality of chambers;
Independent piping for each chamber (1) of CVD (2)
A plurality of independent abatement equipment units connected in (4),
It has an outlet scrubber (10) for collecting and cooling and cooling the gas treated in the abatement equipment unit, and the abatement equipment unit has an inlet scrubber (5) and a heating oxidative decomposition zone (7). As a reaction tube , wherein the reaction tube is a partition wall
All the abatement equipment units come together through contact
Are housed in one cabinet .

According to this, each chamber is connected to an independent abatement equipment unit by an independent pipe. Each abatement equipment unit is provided with an inlet scrubber and a heat oxidative decomposition zone (reaction tube), so that the entire apparatus has the same number of inlet scrubbers and heat oxidative decomposition zones (reaction tubes) as the number of chambers.

In this method, the exhaust gas for deposit, purging and cleaning is introduced from each chamber to the independent abatement equipment unit by independent piping according to the time sequence. The exhaust gas for deposits and cleaning is thermally decomposed and harmed.

That is, there is no danger of simultaneous discharge and mixing of the exhaust gas for deposit and the exhaust gas for cleaning with the danger of explosion, and it is safe.

The gas treated in each of the abatement units is collected in a common outlet scrubber, washed and cooled, and then discharged to the atmosphere. In other words, the abatement process is performed in each abatement facility unit, but subsequent facilities such as an outlet scrubber, a water tank, and a fan can be used in common. Therefore, the configuration of the equipment is simplified, and the installation area of the equipment can be reduced as compared with the conventional one.

[0016]

In addition, the same number of reaction tubes as the number of chambers are brought into contact with each other via a partition wall and then brought together, so that there is an overall heat retaining effect, loss due to heat release is suppressed, and an energy saving effect is enhanced.

Further, since a plurality of inlet scrubbers and reaction tubes are assembled and integrated in a cabinet, the abatement apparatus provided with multiple functions has a simple structure including piping without taking up an installation area. .

The method for removing harmful gas from semiconductor production according to the present invention comprises:
Each chamber of CVD (2) having a plurality of chambers (1)
The exhaust gas from (1) is provided with a reaction tube as an inlet scrubber (5) and a heating oxidative decomposition zone (7) , respectively, wherein the reaction tube is
All abatement equipment units are contacted and gathered through bulkheads.
The gas is guided to independent abatement equipment units housed in a single cabinet , respectively, to abate, and the ablated gas is collected in a common outlet scrubber (10), washed, cooled, and released to the atmosphere. Of semiconductor manufacturing exhaust gas
Therefore, a series of abatement processes stagger each time
It is characterized in that it progresses in accordance with the sequential operation of the bar .

According to this, since the exhaust gas from each chamber is eliminated by the independent abatement equipment unit, there is no danger of simultaneous exhausting and mixing of the exhaust gas for the deposit and the exhaust gas for the cleaning with the danger of explosion. It is safe. Also, because a common exit scrubber and water tank can be used,
Exhaust gas removal in the case of using multi-chamber type CVD can be performed in a small area. In addition, thermal oxidative decomposition
A reaction tube as zone (7) is provided, and the reaction tube
All abatement equipment units are contacted and gathered through bulkheads.
Are housed in one cabinet and a series of abatement
Processed to operate each chamber sequentially while shifting the time
So that it progresses in response to
The required energy (heat) differs for each abatement process
Energy between adjacent reaction tubes through partition walls
Exchange of energy and eliminate energy loss
Overall, reducing the amount of energy required for abatement.
You.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a conceptual diagram of an apparatus when the present invention is constituted by, for example, three chambers. In the figure
(1) is a chamber provided in the CVD apparatus (2). The gas in the chamber (2) is exhausted to independent exhaust gas introduction pipes (4) by an exhaust pump (3).

The exhaust gas introduction pipes (4) are connected to independent inlet scrubbers (5). The inlet scrubber (5) is provided with a spray nozzle (5a) for injecting water, and the atomized high-pressure water ejected from the spray nozzle (5a) is used to spray Si.
Dust such as O ₂ , SiF ₄ and F ₂ , water-hydrolyzable substances and water-soluble components are washed away with water.

The inlet scrubber (5) is a pipe for introducing exhaust gas after cleaning.
It is connected to the reaction tube (7) via (6). As a countermeasure against the corrosion of fluorine-based corrosive gas generated as a result of thermal decomposition of the cleaning exhaust gas, the reaction tube (7) is made of a ceramic whose surface is entirely made of a high-alumina ceramic as in Japanese Patent Application No. 8-265297. The structure was covered with a material.

A series of abatement processes are carried out at staggered times.
Proceed with the sequential operation of the chamber. C ₂ H ₆ , C
When there is no problem even if PFC such as F ₄ is mixed with, for example, deposited SiH ₄ , N ₂ gas for purging is essentially unnecessary. The thermal decomposition of such PFC requires the presence of O ₂ (usually external air), and the amount added to the amount of air required for oxidative decomposition of SiH ₄ is added to the upper part of the reaction tube (7) or the reaction tube.
It is necessary to introduce it at a position upstream of (7). (9) is an external air introduction pipe, which is connected so as to be able to supply external air to a position upstream of the reaction tube (7).

If the deposit gas and the cleaning gas are mixed and there is a risk of explosion, use SiH
By avoiding both mixed state between SiH ₄ and NF ₃ by purging with N ₂ gas during the deposition and cleaning processes switch if the Example ₄ and NF _3, be abating each independently it can.

In the thermal oxidation decomposition according to the present invention, when the exhaust gas treatment conditions are SiH ₄ , the gas concentration is 0.3 to 1%, and the air flow rate is 1
The heater surface temperature of the reaction tube (7) is 7 at 000 liter / min.
When the temperature is set to 00 ° C., the concentration of SiH ₄ in the released gas is much lower than the reference value TLV (that is, 5 ppm).

The processing conditions of the exhaust gas for cleaning are stricter. For example, when NF ₃ , C ₂ F ₆ , and CF ₄ are representative examples and all gas concentrations are 1 to 4%, the air flow rate is 30 to 600 l / min. 800 ° C or higher, 1000 ° C or higher, 1
Requires a heater surface temperature of 100 ° C. or higher. Under these treatment conditions, the concentration in the released gas was ₃ pp
m and C ₂ F ₆ and CF ₄ can achieve an abatement rate of 90% or more.

Therefore, in the present invention, the set temperature is adjusted to the processing condition of the gas that is most harmful. For example, Si
In the case of the H ₄ / NF ₃ system, the surface temperature of the reaction tube (7) is set to 850.
℃ or more, 1000 ℃ or more for SiH ₄ / C ₂ F ₆ system, Si
In the case of the H ₄ / CF ₄ system, the temperature is set to 1100 ° C. or more, and more specifically, it depends on the exhaust gas air flow.

In the reaction tube (7), SiO ₂ , N ₂ , F ₂ , and HF are newly generated by thermal oxidative decomposition, but dust generated in exhaust gas treatment for deposit, for example, SiO ₂
Is automatically scraped off by the dust scraping mechanism (8),
It falls into the water tank (12) and gathers. Dust scraping mechanism (8)
The one used in Japanese Patent Application No. 9-38318, which was capable of scraping off dust and stirring the inside of the reaction tube (7), was used. However, in the present invention, the dust scraping mechanism is not an essential component. Further, a dust scraping mechanism (8) having a different configuration may be used.

In the present invention, the inlet scrubber (5) and the reaction tube (7) are constituent elements of the abatement equipment unit, and one abatement equipment unit is provided with one inlet scrubber (5) and a reaction cylinder (7). ing. Since the abatement treatment is performed in the abatement equipment unit that is independently connected to each chamber, the simultaneous exhausting and mixing of the deposit exhaust gas and cleaning exhaust gas with the danger of explosion in each abatement equipment unit. There is no danger and it is safe.

FIG. 2 is a diagram showing an example of the arrangement of the components of the apparatus, and FIG. 3 is a diagram showing an example of another arrangement.
These are the reaction tube (7) and the exhaust gas introduction pipe connected to it.
The arrangement of (4) is different. When the reaction tubes are brought into contact with each other via the partition walls and then assembled as described above, the reaction tubes have a heat retaining effect as a whole, a loss due to heat release is suppressed, and an energy saving effect is enhanced.

The gas treated in the reaction tube (7) is sucked by the air discharge fan (11) and guided into the water tank (12). Aquarium
(12) is one, and the treated gas discharged from each reaction tube (7) is collected here.

The collected treated gases are cleaned and gas cooled as they pass through a common outlet scrubber (10). In this case, O ₂ is required for oxidizing SiH ₄ , but usually it is introduced into the upper part of the reaction tube (7) using external air.

The treated gas that has passed through the outlet scrubber (10) is discharged to the atmosphere via an air discharge fan (11). Therefore, only one outlet scrubber (10) and one air release fan (11) are required for the entire apparatus. Since the water tank (12), the outlet scrubber (10), the air release fan (11), the piping, and the like can be integrated into one, the configuration of the entire apparatus becomes simple and the installation area of the apparatus may be small. Also, the piping can be simple.

[Example 1] P having three chambers
SiH ₄ is 0.18 liter / min and NH ₃ is 0.08 per chamber as a deposit gas in CVD.
A mixed gas of 9 L / min, N ₂ of 3.8 L / min, N ₂ O of 1 L / min, and diluted N ₂ of 31 L / min was discharged.

On the other hand, as a cleaning gas, NF ₃ was 0.45 l / min and diluted N ₂ was 1 per chamber.
4.6 liter / min was used. The gas concentration is SiH ₄ 0.5
% And NF ₃ were 3%.

In addition, N ₂ for purging was used between the exhaust gas for depositing and the exhaust gas for cleaning at 30 liter / min per chamber. Further, 6.3 external air was supplied to the upper part of each
Liter / min was introduced.

The heater surface temperature was set at 850 ° C.
After passing through the outlet scrubber and measuring the concentration after the detoxification treatment before release to the atmosphere, both TLVs were significantly lower at 1 ppm or less for both SiH ₄ and NF ₃ .

The amount of circulating water in the inlet scrubber was 5 l / min for each chamber, and the amount of circulating water in the outlet scrubber was 15
It was operated at liter / min.

The size of 2 × 10 × 120 (m
m) A stirring and scraping mechanism using three alumina ceramic strip plates is provided. As a result, there was no phenomenon of dust clogging in the reaction cylinder, and there was no increase in gas flow velocity resistance.

Although the abatement system was operated continuously for 48 hours, no abnormal phenomena such as explosions (sudden pressure fluctuations and temperature rises) occurred, and there was no influence on the P-CVD operation. There was no.

Example 2 Two-chamber PE-CVD
SiH ₄ per each chamber deposit for exhaust gas in the 0.12 liters /min,0.5%PH ₃ (N ₂
Balance) 200 l / min, NH ₃ 1 l / min, TEOS 0.1 l / min, diluted N ₂ 2
A mixed gas of 6 liter / min was discharged.

On the other hand, as a cleaning gas, C ₂ F ₆ was 1 liter / min and O ₂ was 3 liter / min.
min and diluted N ₂ were discharged at 46 l / min. The gas concentration of SiH ₄ + TEOS was 0.8% in total, and C ₂ F ₆ was 2%.
%Met.

Further, between the deposit exhaust gas and the cleaning exhaust gas, N ₂ for purging was used at a rate of 30 liter / min per chamber. Further, O ₂ was further supplied to the upper part of the reaction tube at a rate of 5 L / min per chamber. The heater surface temperature was set at 1100 ° C.

As a result of measuring the concentration of the processing gas at a place after the outlet scrubber, SiH ₄ could not be detected and TEOS was 1
ppm or less, and C ₂ F ₆ was 800 ppm. This means that the abatement rate is 96%.

[0046]

As described above, according to the present invention, a single chamber can cope with multi-chamber CVD, and has a simple structure and a small equipment area, and it is safe even if the equipment area is small. It was possible to provide an exhaust gas elimination method capable of elimination.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration of an apparatus.

FIG. 2 is a diagram showing an example of an arrangement of each device element.

FIG. 3 is a diagram showing another example of the arrangement of each device element.

[Explanation of symbols]

 (1) Chamber (2) CVD equipment (3) Exhaust pump (4) Exhaust gas introduction pipe (5) Inlet scrubber (6) Cleaning exhaust gas introduction pipe (7) Reaction tube (8) Dust scraping mechanism (9) External air Inlet pipe (10) Outlet scrubber (11) Air release fan (12) Water tank

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/205 C23C 16/44 B01D 53/34

Claims (2)

(57) [Claims] 1. A plurality of independent abatement equipment units connected to each chamber of a CVD having a plurality of chambers by independent pipes, and a gas processed by the abatement equipment unit is collected and commonly cleaned, It has an outlet scrubber for cooling, and the abatement equipment unit has an inlet scrubber and a reaction tube as a heating oxidative decomposition zone, and the reaction tube is provided with a partition wall.
All the abatement equipment units are
A semiconductor manufacturing exhaust gas abatement apparatus characterized by being housed in one cabinet . 2. An exhaust gas from each chamber of a CVD system having a plurality of chambers is provided with an inlet scrubber and a reaction tube as a heating oxidative decomposition zone , respectively.
All abatement equipment units so that they contact and gather through the wall
To separate harm removal equipment units housed in a single cabinet , respectively, to remove the harm, collect the removed gas in a common outlet scrubber, wash and cool it, and then release it to the semiconductor exhaust gas In the abatement method, a series of abatement processes are carried out at different times for each chamber.
A method for removing exhaust gas from semiconductor manufacturing, wherein the method is adapted to proceed in accordance with sequential operation .