JP3542733B2 - Fixed orifice and discharge system using the same - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fixed orifice that efficiently discharges a fixed amount of exhaust gas at a set pressure with respect to a set pressure of an exhaust gas containing a by-product from a CVD apparatus, for example, and a discharge system using the fixed orifice.
[0002]
Problems to be solved by the prior art and the invention
For example, in a vapor phase growth apparatus for performing vapor phase growth on a substrate (wafer) such as silicon, there are by-products such as by-products of the reaction from chemical vapor deposition on the substrate, and it is necessary to efficiently discharge these by-products. is there.
For this reason, conventionally, an orifice limited area is formed in a discharge line to purify the orifice limited area.
[0003]
FIG. 9 shows an outline of a normal pressure CVD apparatus.
As shown in FIG. 9, a chemical vapor and a chemical gas 02 are supplied to the dispersion head 01 and nitrogen (N ₂ 3.) The film is formed by chemical vapor deposition on the surface of the wafer W carried by the substrate supply means (not shown) in the clean tunnel 03 in the gas atmosphere. The gas (process gas) and by-products that do not contribute to the chemical vapor deposition are discharged to the outside as a discharge gas 04 from a discharge pipe 05 connected to the dispersion head 01.
[0004]
The discharge system needs to discharge gas at a predetermined rate so as to provide a predetermined reaction time between the chemical vapor deposition gas in the dispersion head 01 and the wafer W. This is because if the gas is discharged quickly, it is discharged outside before the reaction takes place, and the raw material gas does not contribute to the chemical vapor deposition and is wasted.On the other hand, if the gas discharge is delayed, the gas flow will fluctuate. This is because uniform chemical vapor deposition cannot be performed.
[0005]
For this reason, in the related art, an orifice area limit is provided in a discharge line to which a fixed amount of exhaust gas is supplied, and the discharge line is optimized by the orifice area limit.
FIG. 10 shows an example of a schematic view of this conventional fixed orifice. As shown in FIG. 10, a discharge valve 05 for discharging a discharge gas 04 connected to a dispersion head 01 is provided with a ball valve 07 having an opening 06 that can be freely changed by a manual or automatic variable motor M provided outside. The opening 06 of the ball valve 07 is opened together with the accumulation of by-products, and the flow rate of the exhaust gas 04 discharged from the exhaust box 08 is restricted.
[0006]
However, in the case of using the ball valve 07, powder of by-products also accumulates in the orifice opening, and the flow rate changes because the opening is narrowed. Even at the time of opening, it is necessary to always clean the sediment before the sediment accumulates and becomes clogged, and each time it is troublesome.
In addition, there is a problem that the deposits deposited in the openings are discharged at once, which causes a change in the amount of exhaust gas, which affects the film formation.
[0007]
FIG. 11 shows another example. As shown in FIG. 11, a pair of rotatable rollers 011 and 011 provided in the discharge pipe 05 so as to face each other, and a scraper 012 that slides on the outer surface of the roller 011 and cleans the surface. An orifice is formed by opposing the roller 011, and the accumulated by-products are removed by hitting the scraper 012 by rotating the roller.
[0008]
However, the method of removing the deposit by the roller 011 and the scraper 012 has a problem that if a large amount of deposit is deposited on the roller and the scraper, the deposit can no longer be removed by rotation.
[0009]
For this reason, for example, a method has been proposed in which the orifice is cleaned by rotating the inside of the orifice diameter with the wire using a rotating metal wire or the like. However, there is a problem that the deposition of deposits occurs, and the deposition of the deposits hinders normal gas flow.
[0010]
In view of the above circumstances, the present invention keeps the pressure in the reaction section constant by collecting exhaust gas containing by-products contained in exhaust gas of a CVD apparatus or the like and passing it through a constant orifice that does not change. It is an object of the present invention to provide a fixed orifice capable of ensuring uniformity of a thin film formed on a wafer and a discharge system using the same.
[0011]
[Means for Solving the Problems]
The invention of claim 1 which solves the above problem is Includes by-products emitted after subjecting the material to chemical vapor deposition An orifice arranged in a discharge line for discharging exhaust gas and having a thin ring shape having pores, and a gas inlet for holding the orifice and collecting exhaust gas and an outlet for discharging gas after passing through the orifice. Orifice body having a predetermined interval in the orifice body so that the orifice is perpendicular to the gas flow, and a predetermined amount of inert gas is introduced into the gap and held. It is characterized by the following.
[0012]
[Claim 2] Is Claim 1 Wherein the inert gas is any one of nitrogen gas, helium gas, argon gas, carbon dioxide and air or a mixture thereof, and the above-mentioned inert gas decreases as the amount of exhaust gas passing through the orifice body decreases. It is characterized in that the supply amount of the inert gas is reduced and the exhaust gas amount is kept constant.
[0013]
[Claim 3] Is Claim 1 In the fixed orifice described in (1), the ring-shaped orifice is characterized in that a downstream side of the gas flow is a tapered cylinder with a small diameter flange.
[0014]
[Claim 4] Is Claim 3 Wherein the tapered angle (θ) from the direction perpendicular to the gas flow of the ring-shaped orifice is not more than 80 degrees.
[0016]
[Claim 5] Is installed in a storage chamber under a predetermined pressure, is provided with a chemical vapor deposition means for performing chemical vapor deposition on an object to be vapor-deposited, a discharge line for discharging exhaust gas from the chemical vapor deposition means, and interposed in the discharge line. Claims 1 to 4 And a blower fan that is installed inside or outside the storage chamber and discharges exhaust gas from the discharge line to the outside of the storage chamber. When deposits and by-products accumulate and the emission amount of exhaust gas decreases, the supply amount of inert gas supplied to the fixed orifice is reduced as the emission amount decreases, and a constant emission amount is maintained. It is characterized in that the deposition atmosphere is kept constant.
[0017]
[Claim 6] Is Claim 5 In the fixed orifice described in (1), the chemical vapor deposition is either a normal pressure method or a reduced pressure method.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.
[0019]
FIG. 1 shows a schematic view of a fixed orifice according to the present embodiment. 2 is a partially cutaway structural view of the fixed orifice, FIG. 3 is a sectional view taken along the line III-III of FIG. 2, and FIG. 4 is an enlarged view of a portion IV in FIG.
[0020]
As shown in FIGS. 1 to 4, the fixed orifice 11 according to the present embodiment is discharged without contributing to the reaction after performing the chemical vapor deposition on the wafer W in the lower reaction part of the dispersion head 12. An exhaust pipe 16 for exhausting a process exhaust gas (reaction gas, nitrogen carrier gas, selector gas) 13 and an exhaust gas 15 containing a powdery reaction by-product 14 is provided. An orifice 18 having a thin ring-shaped orifice 18 having a hole 17, a gas inlet 19 for holding the orifice 18 therein, a gas inlet 19 for collecting the exhaust gas 15, and an exhaust gas 20 for discharging the exhaust gas after passing through the orifice And a main body 21.
[0021]
The thin ring-shaped orifice 18 is held while having a gap 22 at a predetermined interval so as to be orthogonal to the gas flow of the exhaust gas 15, and the gap 22 is provided with a predetermined amount of system gas from outside. Inert gas (for example, N ₂ ) Is supplied from the gas supply unit 23, and a predetermined exhaust amount is secured, and the exhaust gas 24 is exhausted from the exhaust port 20 while maintaining the pressure constant by the supply amount of the nitrogen gas. In the drawings, reference numeral 25 indicates a seal member and reference numeral 26 indicates a seal ring.
[0022]
Here, in the present invention, the inert gas is N ₂ The gas is not limited, and may be any one of helium gas, argon gas, carbon dioxide, air, or a mixture thereof. In the following, N is used as an inert gas. ₂ The case where gas is used will be described.
The exhaust gas (exhaust gas downstream of the orifice) 24 exhausted from the fixed orifice 11 is the exhaust gas 24 that is introduced into the orifice body 21 together with the powdery by-product 14 and the inert gas. Gas.
[0023]
As a method for supporting the orifice 18 in the present embodiment, as shown in FIG. 4, for example, a first support member 28 provided with a notch 27 having an L-shaped cross section, and an end surface 29 side of the notch 27 And an orifice support portion 31 composed of a second support member 30 which forms a concave portion in contact with the second support member 30. As shown in FIG. 3, the orifice 18 is supported by concentrically arranging a plurality of the support portions 31 (three in the present embodiment).
The orifice 18 has an optimal orifice diameter (small diameter) 17 for controlling the exhaust of the process gas. The orifice diameter 17 is not specified, and the orifice 18 has a different diameter for each exhaust port. The fixed orifice 11 provided with 18 may be interposed.
That is, the CVD apparatus is provided with a plurality of dispersion heads, and discharge lines are individually formed from the heads. Therefore, the atmosphere of a clean room or the like to be installed, the gas-tight structure of the CVD apparatus, and the structure of the dispersion head. Due to various characteristics, pressure fluctuations can be individually dealt with.
When the opening of the orifice diameter (small diameter) 17 is d, it is preferable that d is in the range of 1d to 0.4d. That is, for example, when the opening d is 15 mm, the range is d = 15 mm to 0.6 mm. Although the pipe diameter D at this time is 42 mm, the present invention is not limited to this.
[0024]
The nitrogen gas supplied to the fixed orifice body 21 via the gas supply unit 23 is a nitrogen gas swirling introduction unit (N ₂ The gas is supplied from the revolving portion 32 to the gap 22 and exhausted. As a result, by-products are prevented from adhering while preventing the generation of turbulence in the orifice main body 21, and the orifice held in the gap 22 is vibrated by discharging nitrogen, thereby preventing adhesion.
Preferably, the gap 22 is about 0.1 mm.
[0025]
That is, the system N supplied to the orifice body 21 ₂ Is introduced in order to maintain the orifice diameter 17 and control the amount of the exhaust gas 15 that is the process exhaust gas. ₂ The gas enters the swirl part 32 uniformly from the surroundings through the gap 22 through the gap 22 to prevent the by-products and the like contained in the exhaust gas 15 from adhering due to the gas flow near the sonic velocity.
[0026]
The structure for supporting the orifice in the fixed orifice is not limited to the above-described structure, but any support method may be used as long as the orifice is supported with a gap and the orifice vibrates by supplying nitrogen gas. Methods can also be employed.
In the present invention, the ring-shaped orifice is not limited to the vibrating type as described above, but may be fixed.
[0027]
By providing the fixed orifice 11 having such a configuration, the process exhaust gas from the head exhaust (orifice upstream side) side is taken in, the pressure can be controlled by supplying nitrogen gas, and the exhaust gas in the lower reaction section of the dispersion head can be exhausted. The process exhaust gas introduced into the orifice body and the system N ₂ Can be discharged so as to always have a constant exhaust pressure in an exhaust box sucked by a blower fan.
[0028]
If the by-product fine particles slightly adhere to the exhaust pipe or the orifice before the fixed orifice due to the change over time due to long-term use, the differential pressure, which is separately monitored, corresponds to the change in the drop. By gradually reducing the supply of nitrogen gas to be supplied, the pressure in the lower reaction section of the dispersion head can be kept constant without changing the amount of exhaust gas as a whole.
[0029]
FIG. 5 schematically shows a discharge system using the fixed orifice of the present invention. As shown in FIG. 5, in a clean room 41 under a predetermined pressure, a fixed orifice 11 is interposed in a discharge pipe 43 which is a discharge line connected to a dispersion head 42 of a chemical vapor deposition means. The exhaust gas 44 from the exhaust pipe 43 is exhausted outside the clean room 41 by the blower fan 46 via the exhaust box 45.
The first pressure gauge P in the clean room 41 ₁ Assuming that the discharge amount of the exhaust box 45 sucked by the blower fan 46 is constant, the first pressure gauge P ₁ And a pressure gauge (negative pressure) P provided in the exhaust pipe 43 ₂ , P ₃ By measuring the pressure difference with the predetermined time or constantly, the discharge status can be confirmed.
If fine powder of by-products adheres to the exhaust pipe or the like before the fixed orifice or the pipes such as the fixed orifice 11 or the discharge pipe after the fixed orifice to some extent due to aging due to long-term use, the fixed orifice Since the amount of exhaust gas passing through the discharge head 11 decreases, the pressure in the lower reaction section of the dispersion head 42 is kept constant without changing the overall amount of exhaust gas by gradually reducing the supply of nitrogen gas to be supplied. It can be.
As a result, even if chemical vapor deposition and by-products accumulate in the discharge pipe 43 and the discharge amount of the discharge gas 44 decreases, the supply amount of the inert gas supplied to the fixed orifice 11 decreases as the discharge amount decreases. By reducing the amount, it is possible to maintain a constant discharge amount and maintain a constant chemical vapor deposition atmosphere.
[0030]
As described above, the fixed orifice 11 has a physical orifice diameter, has a space for supplying a system nitrogen gas therein, and has a process gas discharged from a reactor reaction section of the CVD apparatus, the dispersion head, and its periphery. Reaction gas, nitrogen carrier gas, selector N ₂ The exhaust gas containing powdery by-products after the reaction of the gas is collected and allowed to pass through to keep the pressure in the reaction section constant and to ensure the uniformity of the thin film formed on the wafer. ing.
For this reason, in order to secure a specific displacement, the physical orifice diameter is specified.
When a plurality of exhaust ports are provided, the physical orifice diameter of the fixed orifice attached to each port is specified so as to achieve balance.
After the balance of the plurality of exhaust ports has been adjusted, fine exhaust balance can be adjusted by adjusting the amount of system nitrogen gas supplied. Thereby, the uniformity of the thin film can be further improved.
[0031]
In order to secure a specific exhaust amount, a differential pressure port is provided, and the exhaust pressure can be kept constant by automatically controlling the flow rate of system nitrogen with an MFC (mass flow controller) for the differential pressure. That is, the amount of nitrogen gas introduced is automatically controlled based on the differential pressure while monitoring with a pressure sensor provided at a predetermined location, thereby making it possible to make the exhaust amount constant.
[0032]
Although the above-described orifice has been described as a ring-shaped flat orifice, the present invention is not limited to the flat orifice, and the ring-shaped orifice as shown in FIG. A tapered cylinder with a flange may be used.
That is, as shown in FIG. 6, similarly to the fixed orifice shown in FIG. 1, the fixed orifice 101 has a small-diameter hole (orifice opening) 102 flange 103 on the downstream side of the gas flow of the exhaust gas 15. An orifice body having an orifice 105 formed of a tapered cylinder 104, a gas inlet 19 for holding the orifice 105 with a predetermined gap therein, and a gas inlet 19 for collecting the exhaust gas 15 and an outlet 20 for discharging the exhaust gas after passing through the orifice. And N introduced into the swirl introducing section 32. ₂ The gas passes through the predetermined gap 22 to the gas outlet 20 ₂ I am trying to emit gas.
The angle of the ring-shaped orifice tapered cylinder 104 may be such that the taper angle (θ) from a direction perpendicular to the gas flow of the exhaust gas 15 is 80 degrees or less. Although the taper angle of 0 degree is the orifice in the shape of a flat plate shown in FIG. 1 described above, the supply gas is obliquely injected toward the downstream of the gas flow by forming the tapered cylindrical shape, so that the by-products adhere. As a result, the exhaust efficiency is improved, and it becomes possible to flexibly cope with aging over a longer period of time as compared with the ring-shaped orifice.
When the angle is 80 degrees or more, it is difficult to form a tapered cylinder, and it is not possible to improve the exhaust efficiency. Therefore, the upper limit of the taper angle (θ) is set to about 80 degrees.
The holding type of the fixed orifice 101, the orifice hole diameter, and the like are the same as those of the above-described fixed orifice 11, and the description thereof is omitted.
[0033]
As described above, the fixed orifice according to the present invention is disposed in the discharge line that discharges the exhaust gas containing by-products that are discharged after subjecting the deposition target to chemical vapor deposition, and has a thin ring shape having pores. And an orifice body holding the orifice and having a gas inlet for collecting exhaust gas and an outlet for discharging gas after passing through the orifice. The orifice is provided with a gas in the orifice body. A gap is provided at a predetermined interval so that the flow has an angle of about orthogonal to about 80 degrees, and a predetermined amount of inert gas is introduced and held in the gap, so that the following effects are obtained. Play.
(1) The diameter of the fixed orifice can be easily selected.
(2) An orifice of an arbitrary diameter can be set for each exhaust pipe.
{Circle around (3)} The control can be performed by supplying only the inert gas and the air and the like, and the running cost is low because the electricity, the motor and the like are not used.
(4) By flowing inert gas, air, etc. as system gas, adhesion of by-products such as powder is prevented, and exhaust gas control is performed by individually changing the orifice hole diameter according to the installation line. For a long time.
{Circle over (5)} Since the orifice is held inside the orifice body with a predetermined gap, by flowing the system gas, the orifice vibrates minutely and powder or the like is prevented from adhering.
{Circle around (6)} By adjusting the flow rate of the gas by the supply of the inert gas, it is possible to control the amount of exhaust gas.
{Circle around (7)} The flow rate of the inert gas can be controlled by an external signal based on the differential pressure before and after the fixed orifice, and the displacement can be automatically controlled.
(8) Since a driving component driven from the outside such as a motor is not used as in the related art, there is no failure or the like.
[0034]
【Example】
FIG. 7 is a schematic diagram of an atmospheric pressure CVD apparatus using three dispersion heads.
In the CVD apparatus shown in FIG. 7, a process gas discharged from the first head 51, the second head 52, and the third head 53 is interposed in a discharge pipe 54 of a discharge gas containing a by-product that does not contribute to thin film formation. The hole diameters of the six fixed orifices 55 are changed. In the present embodiment, the first fixed orifice 55a and the sixth fixed orifice 55f interposed in the discharge pipes 56 and 57 provided outside the first head 51 and the third head 53 have a hole diameter of 17 mm. The other fixed orifices 55b, 55c, 55d, 55e have a hole diameter of 13 mm.
N to be supplied to each fixed orifice 55a to 55f ₂ When the wafer was subjected to chemical vapor deposition at a gas flow rate of 5 liters / minute, good vapor deposition could be performed over a long period of time. In addition, supply N ₂ The supply amount of gas is related to the amount of gas flowing through the discharge pipe of the discharge line and the amount of adhesion of intermediate deposits.Therefore, the supply amount is not limited at all. It is not necessary, and it is effective even in the case of supplying a large amount of 50 l / min. ₂ Since the gas is consumed, it may be replaced appropriately.
[0035]
Next, an example of a CVD apparatus provided with an exhaust gas facility provided with a fixed orifice according to the present invention will be described below.
[0036]
FIG. 8 is an overall system of a normal pressure CVD apparatus according to the present embodiment.
As shown in FIG. 8, the present atmospheric pressure CVD apparatus includes a wafer supply / collection unit 61 for automatically supplying a wafer W onto a transfer tray or collecting the wafer W into a wafer storage box, and a supplied wafer W to a chemical vapor deposition apparatus. A wafer transfer unit 62 for transferring, a chemical vapor deposition unit 63 for forming an oxide film on the wafer W, a wafer return unit 64 for transferring the wafer on which the oxide film is deposited to a wafer collection position while being placed on a tray, The control unit (not shown) controls the wafer supply / collection unit 61, the transport unit 62, the chemical vapor deposition unit 63, and the return unit 64 according to a preset program.
[0037]
Hereinafter, the system flow of the normal pressure CVD apparatus will be described with reference to FIG.
{Circle around (1)} The wafer supply / collection unit 61 is provided in the first cabinet 65, and the transfer unit 62, the chemical vapor deposition unit 63, and the return unit 64 are provided in the second cabinet 66, respectively.
The wafer W is stored in the wafer cassette port 67 constituting the wafer supply unit 61.
The tray (made of SiC) 68 on which the circulating wafer W is placed is moved from below to a fixed position by an uplift 69 and an uplift fork 70, and waits in a state where the wafer W can be loaded.
The pin member 89 is lifted up from the wafer cassette port 67 to the SiC tray 68 waiting on the uplift fork 70 by the wafer transfer robot 71 by the wafer transfer robot 71, the wafer W is loaded on the pin member 89, and the pins are lifted down. Then, the wafer W is loaded.
[0038]
(2) The SiC tray 68 loaded with the wafer W is transferred to the guide rail 72 of the wafer transfer section 62 by the uplift fork 70.
The SiC tray 68 transferred to the guide rail 72 is sequentially conveyed on the guide rail 72 at a constant speed by a tray driving mechanism 73.
The SiC tray 68 is N ₂ The wafer W on the SiC tray 68 is uniformly raised to a target temperature by a heater (not shown) charged in the guide rail 72 while passing through the inside of the clean tunnel 74, and is introduced into the reaction section of the chemical vapor deposition section 63.
[0039]
{Circle around (3)} The reaction section of the chemical vapor deposition section 63 is composed of a head base member 75, a dispersion head 76, a triangular duct 77, a fixed orifice 78, and a discharge pipe 79. Is uniformly discharged from the dispersion head 76, and a thin oxide film is formed on the wafer W by exhaust controlled by a fixed orifice 78 interposed between the triangular duct 77 and the discharge pipe 79. The exhausted process residual gas passes through an exhaust duct 81 via a process exhaust box 80 and is exhausted.
The wafer W having the oxide film formed thereon exits the reaction part of the chemical vapor deposition part 63 while being loaded on the SiC tray 68, is collected by the downlift fork 82, and is conveyed downward by the downlift 83.
[0040]
{Circle around (4)} The SiC tray 68 conveyed downward passes from the SiC tray receiver 84 of the tray return portion 64 through a clean airflow that has passed through the ulper filter member 85, and is transferred onto the wafer uplift fork 70. And is transported to a fixed position above.
When the SiC tray 68 reaches the upper fixed position, only the wafer W on which the oxide film is formed on the SiC tray is moved up by the pin member 89.
The lifted wafer W is collected by the wafer transfer robot 71 and transferred to a cooling port 86 for cooling the heated wafer W.
[0041]
{Circle around (5)} The wafer W cooled by the cooling port 86 is recovered and accommodated in the original position of the wafer cassette port 67 as a substrate stacking device in place of the wafer to be transported next.
{Circle around (6)} By repeating the above, the wafer W can be processed continuously.
[0042]
{Circle around (7)} When a film having a constant thickness is deposited on the SiC tray 68 by continuous thin film formation, the used SiC tray 68 is collected in the SiC tray rack 87 while the SiC tray 68 is transported at a constant speed by the automatic SiC tray exchange function. Then, the cleaned and cleaned SiC tray 68 can be carried out of the SiC tray rack 87 and automatically replaced. The replaced SiC tray 68 is taken out of the apparatus together with the tray rack 87 by the tray exchange mechanism 88 and transferred to the cleaning step.
[0043]
In the above-described CVD apparatus, a fixed orifice is provided in an exhaust line of the chemical vapor deposition section 63, and by adjusting the amount of nitrogen gas supplied to the fixed orifice, predetermined stable exhaust can be performed, and good chemical vapor deposition can be performed on the wafer W. Can be applied. Further, even when powders of by-products adhere to the discharge line, the exhaust control means gradually reduces the nitrogen supply amount as the exhaust pressure fluctuates, thereby enabling stable exhaust to be performed continuously. Does not fluctuate.
[0044]
【The invention's effect】
As described in detail above, a thin ring-shaped orifice having pores is disposed in an exhaust line that exhausts an exhaust gas containing a by-product that is exhausted after performing chemical vapor deposition on an object to be deposited, and the orifice. And an orifice body having a gas inlet for collecting exhaust gas and an outlet for discharging gas after passing through the orifice. The orifice is inserted into the orifice body at an angle of 80 degrees perpendicular to the gas flow. It has a gap at a predetermined interval so as to have a degree angle, and a predetermined amount of inert gas is introduced and held in the gap to secure a predetermined exhaust amount and to maintain a constant pressure. Exhaust gas can be exhausted.
[Brief description of the drawings]
FIG. 1 shows a schematic view of a fixed orifice according to the present embodiment.
FIG. 2 is a partially cutaway structural view of a fixed orifice.
FIG. 3 is a sectional view taken along line III-III of FIG. 2;
FIG. 4 is an enlarged view of a part IV in FIG. 2;
FIG. 5 is a schematic view of a discharge system using a fixed orifice.
FIG. 6 is a schematic view of another fixed orifice.
FIG. 7 is a schematic diagram of an atmospheric pressure CVD apparatus using three dispersion heads.
FIG. 8 is an overall system diagram of a normal pressure CVD apparatus according to the present embodiment.
FIG. 9 schematically shows a normal pressure CVD apparatus.
FIG. 10 is a schematic view of a conventional fixed orifice.
FIG. 11 is a schematic view of another conventional fixed orifice.
[Explanation of symbols]
11 Fixed orifice
12 dispersion head
13 Process gas
14 Reaction by-products
15 Exhaust gas
16 Discharge pipe
17 holes (orifice opening)
18 orifice
19 Gas inlet
20 outlet
21 Orifice body
22 gap
23 Gas supply unit
24 Exhaust gas
25 Sealing member
26 Seal ring

Claims (6)

Disposed on an exhaust line that exhausts exhaust gas containing by-products that are emitted after subjecting the object to be deposited to chemical vapor deposition ,
A thin ring-shaped orifice having pores,
An orifice body holding the orifice and having a gas inlet for collecting exhaust gas and an outlet for discharging gas after passing through the orifice,
A fixed orifice having a predetermined gap in the orifice main body so as to be orthogonal to a gas flow, and a predetermined amount of inert gas being introduced into and held in the gap. . The fixed orifice according to claim 1 ,
The inert gas is any one of nitrogen gas, helium gas, argon gas, carbon dioxide, and air, or a mixture thereof. As the amount of exhaust gas passing through the orifice body decreases, the supply amount of the inert gas decreases. A fixed orifice characterized by a reduction and a constant emission. The fixed orifice according to claim 1 ,
The fixed orifice, wherein the ring-shaped orifice is a small-diameter tapered cylinder with a flange on the downstream side of the gas flow. The fixed orifice according to claim 3 ,
A fixed orifice, wherein a taper angle (θ) from a direction perpendicular to a gas flow of the ring-shaped orifice is 80 degrees or less. Installed in a containment room under a predetermined pressure,
Chemical vapor deposition means for performing chemical vapor deposition on the object to be deposited,
An exhaust line for exhausting the exhaust gas from the chemical vapor deposition means,
A fixed orifice according to any one of claims 1 to 4 , which is interposed in the discharge line;
A blower fan that is installed inside or outside the storage room and discharges exhaust gas from the discharge line to the outside of the storage room,
When chemical vapor deposition and by-products accumulate in the exhaust line in front of the fixed orifice and the emission amount of the exhaust gas decreases, the supply amount of the inert gas supplied to the fixed orifice is reduced as the emission amount decreases, A discharge system using a fixed orifice, which maintains a constant discharge rate and maintains a constant chemical vapor deposition atmosphere. The fixed orifice according to claim 5 ,
A discharge system using a fixed orifice, wherein the chemical vapor deposition is one of a normal pressure method and a reduced pressure method.

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