JP2004104034A - Semiconductor manufacturing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor manufacturing apparatus in which the clogging of an exhaust piping system is effectively prevented. <P>SOLUTION: Inside a first exhaust pipe 41 connected to an exhaust port 20 of the exhaust piping system 40 of which the upstream end is connected to a treatment chamber 14 for treating a wafer 1 and the downstream end is connected to an exhaustion device, a cover pipe 47 having outflows 52 and 53 is inserted via a buffer 46 to lead antisticking gases 44 into the buffer 46. When the antisticking gases are led into the buffer in the case of exhaustion by the exhaust pipe, the antisticking gases flow out of the outflow of the cover pipe to cut off the contact of a by-product or the like which is contained in the exhausted gases flowing down in the exhaust pipe and is easy to stick to the surface of the exhaust pipe, such that the by-product or the like easy to deposit is prevented from being stuck to the inner peripheral surface of the exhaust pipe or the cover pipe. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor manufacturing apparatus, for example, in a method of manufacturing a semiconductor integrated circuit device (hereinafter, referred to as an IC), various heat treatments are applied to a semiconductor wafer (hereinafter, referred to as a wafer) on which an integrated circuit including a semiconductor element is to be manufactured. The present invention relates to a heat treatment apparatus (furnace) for performing (thermal treatment).
[0002]
[Prior art]
2. Description of the Related Art In a method of manufacturing an IC, a batch type vertical hot wall type low pressure CVD apparatus is widely used for depositing silicon nitride (Si ₃ N ₄ ), silicon oxide (SiO x), polysilicon and the like on a wafer. ing. A batch type vertical hot wall type reduced pressure CVD apparatus (hereinafter, referred to as a CVD apparatus) is constituted by an inner tube forming a processing chamber, an outer tube surrounding the inner tube, and a vertically installed process tube, and exhausting the processing chamber. A manifold connected to an exhaust pipe system and a gas introduction pipe for supplying gas to the processing chamber, a heater unit laid outside the process tube to heat the processing chamber, and a plurality of wafers aligned vertically. And a boat for holding and carrying the wafer into the processing chamber. The boat holding a plurality of wafers is loaded (boat loading) from the furnace port at the lower end into the processing chamber, and a film forming gas is supplied to the processing chamber from the gas introduction pipe. The processing chamber is heated by the heater unit while being supplied, so that the CVD film is deposited on the wafer. It is.
[0003]
In a conventional CVD apparatus of this type, particles (particles) such as residual film forming gas, by-products, and dust accumulate in a place where the exhaust pipe system is likely to adhere, such as a joint portion of the exhaust pipe system. Therefore, a gas introduction port is provided at an upstream portion of a place where the joint portion or the like of the exhaust pipe easily adheres, and an anti-adhesion gas such as nitrogen gas is flown to prevent the gas from being deposited on the exhaust pipe system. Has been implemented.
[0004]
[Problems to be solved by the invention]
However, a gas introduction port is provided at an upstream portion of a place where the exhaust pipe system is likely to adhere, such as a joint portion, and an anti-adhesion gas such as nitrogen gas is supplied to prevent by-products from being deposited on the exhaust pipe system. In the CVD apparatus, the adhesion preventing effect is not exerted on the portion of the exhaust pipe upstream of the gas introduction port or on the opening (exhaust port) in the manifold of the exhaust pipe system. However, there is a problem in that, for example, they adhere to the exhaust port and accumulate.
[0005]
An object of the present invention is to provide a semiconductor manufacturing apparatus capable of effectively preventing clogging of an exhaust pipe system.
[0006]
[Means for Solving the Problems]
The semiconductor manufacturing apparatus according to the present invention includes an exhaust pipe having one end connected to a processing chamber for processing the substrate and the other end connected to an exhaust device, and a coating pipe having an outlet inside the exhaust pipe. It is inserted through a buffer, and is configured so that an anti-adhesion gas is introduced into the buffer.
[0007]
According to the above-described means, when the anti-adhesion gas is introduced into the buffer at the time of exhaustion by the exhaust pipe, the anti-adhesion gas flows out of the outlet of the cladding tube, thereby causing the adhesion included in the exhaust gas flowing down the exhaust pipe. Since the contact of easily produced by-products and the like with the surface of the exhaust pipe is blocked, it is possible to prevent easily deposited by-products and the like from adhering to and accumulating on the inner peripheral surface of the exhaust pipe and the cladding pipe.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0009]
As shown in FIG. 1, a CVD apparatus 10 according to the present embodiment includes a vertical process tube 11 which is disposed vertically so that the center line is vertical and is fixedly supported. The process tube 11 includes an outer tube 12 and an inner tube 13 which are arranged concentrically with each other. The outer tube 12 is made of quartz glass or silicon carbide (SiC) and has a cylindrical shape with an upper end closed and a lower end opened. The inner tube 13 is formed integrally, and the inner tube 13 is made of quartz glass or silicon carbide and is formed in a cylindrical shape having upper and lower ends opened. The cylindrical hollow portion of the inner tube 13 forms a processing chamber 14 into which a plurality of wafers held concentrically by a boat are loaded, and a lower end of the inner tube 13 has a processing target substrate. A furnace port 15 having a diameter larger than the maximum outer diameter of the wafer is formed.
[0010]
As shown in FIGS. 1 and 2, a manifold 16 is arranged concentrically at the lower end of the process tube 11, and the process tube 11 is supported vertically by the housing 2. It has become. The manifold 16 is made of a metal such as stainless steel, and is formed in a short cylindrical shape having upper and lower ends opened. A partition 17 which vertically partitions an inner space of the manifold 16 is provided at an intermediate portion of an inner periphery of the manifold 16. It protrudes horizontally. A gas introduction pipe 18 is connected to the lower end of the side wall of the manifold 16 so as to communicate with a lower space on the furnace port 15 side of the inside space of the manifold 16 partitioned by the partition wall 17. Is connected to a gas supply device (not shown) for supplying a gas such as a source gas or a nitrogen gas. An exhaust port 20 to which an exhaust pipe system 40 described later is connected is provided at an upper portion of a side wall of the manifold 16 so as to fully communicate with an upper space of the inner space of the manifold 16 partitioned by the partition wall 17. The opening 20 exhausts an exhaust passage 19 formed by a gap between the outer tube 12 and the inner tube 13.
[0011]
As shown in FIGS. 1 and 2, the CVD apparatus 10 includes a furnace port opening / closing device 21 as an isolation valve for opening and closing the furnace port 15 of the manifold 16. It is arranged so as to be concentric with the extension of the center line and to be raised and lowered by a boat elevator (not shown). A furnace port opening / closing device 21 includes a base 22 vertically moved up and down by a boat elevator, and a seal cap 23 formed in a disk shape substantially equal to the outer diameter of the manifold 16 to tightly contact the lower end surface of the manifold 16 to seal the furnace port 15. The seal cap 23 is disposed in parallel with a slight gap right above the base 22, and is supported horizontally. A rotation shaft 24 rotated by a rotation driving device (not shown) is vertically inserted on the center line of the base 22 and is rotatably supported by a bearing device. Standed vertically and fixed.
[0012]
As shown in FIG. 1, the boat 25 includes a pair of upper and lower end plates 26 and 27, and a plurality of holding members 28 vertically disposed between the both end plates 26 and 27. A plurality of holding grooves 29 are provided in the holding member 28 at equal intervals in the longitudinal direction, and are formed so as to open in the same plane. The wafer 1 is held horizontally by the boat 25 by inserting the outer peripheral portion between the plurality of holding grooves 29 so as to be aligned horizontally and with the centers aligned with each other.
[0013]
As shown in FIG. 1, a heater unit 30 for heating the inside of the process tube 11 is provided concentrically around the outer tube 12 outside the process tube 11. Numeral 30 is configured to heat the inside of the process tube 11 to a uniform or predetermined temperature distribution. The heater unit 30 is configured by helically laying a resistance heater 31 on the inner periphery of a cylindrical heat insulating tank 32 and is vertically installed on the housing 2.
[0014]
As shown in detail in FIG. 2, the exhaust pipe system 40 according to the present embodiment connected to the exhaust port 20 includes a first exhaust pipe 41 connected to the exhaust port 20, and The pipe 41 is formed in a large-diameter cylindrical shape corresponding to the large-diameter exhaust port 20. The end on the inner peripheral surface of the first exhaust pipe 41 on the exhaust port 20 side (hereinafter referred to as the upstream end) and the downstream end on the opposite side to the exhaust port 20 have an upstream side. The positioning portion 42 and the downstream positioning portion 43 are provided so as to project radially inward. An anti-adhesion gas introduction pipe 45 for introducing an anti-adhesion gas 44 such as nitrogen (N ₂ ) gas into the space inside the first exhaust pipe 41 is connected to an intermediate portion of the first exhaust pipe 41 to prevent adhesion. An anti-adhesion gas supply device (not shown) is connected to the gas introduction pipe 45 via a gas heating device 70.
[0015]
Inside the first exhaust pipe 41, a cladding pipe 47 having a telescope (distant glasses) structure slightly smaller in diameter than the inner diameter of the first exhaust pipe 41 is inserted via a buffer 46. That is, the cladding tube 47 has a short center ring 48 formed in a circular ring shape corresponding to the inner diameter of the downstream positioning portion 43 of the first exhaust pipe 41, and the center ring 48 is located downstream of the first exhaust pipe 41. It is fitted into the side positioning portion 43 and positioned concentrically. A flange 49 is projected from the outer periphery of the centering 48, and a seal ring 50 is fitted on the outer periphery of the flange 49. The centering 48 is fixed by being fastened by the pipe joint 56 with the flange 49 and the seal ring 50 sandwiched between the first exhaust pipe 41 and a second exhaust pipe 54 described later. I have. In addition, the covering pipe 47 is provided with a plurality of segment rings 51 which are short and formed in a cylindrical shape having a diameter smaller than the inner diameter of the first exhaust pipe 41 by the size of the buffer 46. The tubes are arranged in series with their center lines aligned, and adjacent ones are fitted at the abutting ends to form a single tube structure. A narrow gap is formed in the fitting portion between the adjacent segment rings 51, 51, and the gap forms an outlet 52 through which the anti-adhesion gas 44 of the buffer 46 flows out into the inner space of the coating tube 47. The segment ring 51 has a different diameter at one end and the other end. The diameter is large on the upstream side of the exhaust gas flow and small on the downstream side so that the adjacent segment rings 51 partially overlap. This makes it easier for the adhesion preventing gas in the buffer 46 to enter the cladding tube 47 and to flow along the inner surface of the cladding tube 47 after entering. Further, it is possible to prevent the exhaust gas flowing in the cladding tube 47 from flowing out into the buffer 46 and to prevent the exhaust gas from adhering inside the cladding tube 47. The upstream end of the segment ring 51 disposed at the most upstream end of the cladding tube 47 is fitted to the upstream positioning portion 42 of the first exhaust pipe 41 with a small clearance, and the clearance prevents the buffer 46 from adhering. An outflow port 53 that allows the gas 44 to flow out to the exhaust port 20 is configured. Then, the downstream end of the segment ring 51 arranged at the most downstream end of the cladding tube 47 is fitted into the inner periphery of the centering 48, so that the cladding tube 47 is provided inside the first exhaust pipe 41 with a predetermined buffer. 46 is fixed to a concentric circle.
[0016]
As shown in FIG. 1, the exhaust pipe system 40 includes a second exhaust pipe 54, and a reducer 55 increases in the middle of the second exhaust pipe 54 as the diameter increases from the upstream side to the downstream side. It is formed so that. The second exhaust pipe 54 is fastened to a downstream end of the first exhaust pipe 41 by a pipe joint 56. A third exhaust pipe 57 is connected to a downstream end of the second exhaust pipe 54 by a pipe joint portion 58, and the anti-adhesion gas 44 is supplied to a space inside the third exhaust pipe 57 in the middle of the third exhaust pipe 57. An anti-adhesion gas introducing pipe 59 to be introduced is connected, and an anti-adhesion gas supply device (not shown) is connected to the anti-adhesion gas introducing pipe 59 via a gas heating device 70. A fourth exhaust pipe 60 is connected to a downstream end of the third exhaust pipe 57 by a pipe joint 61, and a by-product removal unit 62 is connected to one end of the fourth exhaust pipe 60 by a pipe joint 63. ing. A fifth exhaust pipe 64 is connected to a downstream end of the by-product removal unit 62 by a pipe joint 65. Although not shown, the downstream end of the fifth exhaust pipe 64 is connected to an exhaust device constituted by a vacuum pump or the like.
[0017]
Next, a case where a silicon nitride (Si ₃ N ₄ ) film is formed on a wafer by using the CVD apparatus having the above configuration will be described.
[0018]
In the boat loading / unloading chamber just below the process tube 11, the plurality of wafers 1 are loaded into the boat 25 by the wafer transfer device in a state where they are parallel to each other and their center lines are aligned. As shown in FIG. 1, a boat 25 loaded with a plurality of wafers 1 is placed on a seal cap 23 in a state where the direction in which the wafers 1 are lined up is vertical, and is raised by a boat elevator. Then, it is carried into the processing chamber 14 from the furnace port 15 (boat loading), and is left in the processing chamber 14 while being supported by the seal cap 23. In this state, the seal cap 23 is in a state where the furnace port 15 is hermetically sealed.
[0019]
Subsequently, the inside of the process tube 11 is exhausted to a predetermined degree of vacuum (several tens to several tens of thousands Pa) by an exhaust pipe system 40 connected to the exhaust port 20. At this time, since the exhaust port 20 is set to have a large diameter, the exhaust speed of the exhaust port 20 with respect to the exhaust path 19 can be set higher than in the conventional example. It is possible to prevent particles such as residual film-forming gas and by-products from adhering and depositing on the surface of the substrate 16. Further, the inside of the process tube 11 is uniformly heated by the heater unit 30 to a predetermined temperature (about 600 ° C.).
[0020]
When the temperature and pressure inside the process tube 11 are stabilized, the film forming gas 71 is introduced into the processing chamber 14 of the inner tube 13 by the gas introducing pipe 18. In the present embodiment, a SiH ₂ Cl ₂ gas and an ammonia (NH ₃ ) gas are used as a deposition gas. Incidentally, the NH ₃ gas is introduced before the SiH ₂ Cl ₂ gas is introduced. During the processing, the boat 25 is rotated by the rotating shaft 24.
[0021]
The introduced film-forming gas 71 rises in the processing chamber 14 of the inner tube 13, flows out of the upper end opening into the exhaust path 19 formed by the gap between the inner tube 13 and the outer tube 12, and is exhausted from the exhaust port 20. . The deposition gas 71 comes into contact with the surface of the wafer 1 when passing through the processing chamber 14. Due to the thermal CVD reaction by the film forming gas 71 accompanying the contact with the wafer 1, a Si ₃ N ₄ film is deposited (deposited) on the surface of the wafer 1.
[0022]
When a predetermined processing time for depositing a desired thickness of the Si ₃ N ₄ film has elapsed, the seal cap 23 is lowered to open the furnace port 15, and a group of wafers 1 is held in the boat 25. From the furnace port 15 to a boat loading / unloading chamber (not shown) just below the process tube 11 (boat unloading).
[0023]
By the way, when the atmosphere in the processing chamber 14 is exhausted by the exhaust pipe system 40, the remaining film forming gas 71 and all particles such as by-products and dust are removed from the inner wall surface while flowing through the exhaust pipe system 40. Since it comes into contact with an extremely fine uneven surface or a joint of a joint portion, a phenomenon that it adheres to or adheres to these surfaces or gaps and deposits as a foreign matter occurs. In particular, when a sublimable substance such as antimony is used as a raw material gas, it is known that the generation thereof becomes remarkable.
[0024]
Therefore, in the present embodiment, when the inside of the process tube 11 is exhausted by the exhaust pipe system 40, the anti-adhesion gas 44 is caused to flow by the anti-adhesion gas introduction pipes 45 and 59, so that the clogging phenomenon of the exhaust pipe system 40 is prevented. Is prevented. That is, the anti-adhesion gas 44 supplied from the anti-adhesion gas introduction pipe 45 of the first exhaust pipe 41 diffuses into the buffer 46 between the first exhaust pipe 41 and the coating pipe 47, and the buffer 46 has the exhaust pipe system 40. Since the exhaust force is acting, the air is sucked from the plurality of outlets 52 of the cladding tube 47 into the inner space of the cladding tube 47. The adhesion preventing gas 44 sucked into the inner space of the cladding tube 47 flows along the inner peripheral surface of the cladding tube 47 to cover the inner peripheral surface of the cladding tube 47. There is no contact with the inner peripheral surface of 47. Therefore, it is possible to prevent particles such as residual film forming gas, by-products, and dust from adhering and accumulating on the surface of the coating tube 47, that is, the first exhaust pipe 41. Further, since the exhaust force of the exhaust pipe system 40 also acts on the outlet 53 at the upstream end of the coating pipe 47, a part of the adhesion preventing gas 44 supplied to the buffer 46 is partially removed from the upstream end of the coating pipe 47. Is sucked out from the outlet 53 by the exhaust port 20. Since the adhesion preventing gas 44 sucked into the exhaust port 20 covers the exhaust port 20, the exhaust gas does not come into contact with the inner peripheral surface of the exhaust port 20. Accordingly, it is possible to prevent particles such as residual film forming gas, by-products, and dust from adhering and accumulating on the surface of the exhaust port 20.
[0025]
The anti-adhesion gas 44 supplied from the anti-adhesion gas introducing pipe 59 connected to the third exhaust pipe 57 flows along the inner peripheral surface of the third exhaust pipe 57, and thereby flows along the inner peripheral surface of the third exhaust pipe 57. The exhaust gas does not come into contact with the inner peripheral surface of the third exhaust pipe 57 because of being covered. Therefore, it is possible to prevent particles such as residual film forming gas, by-products, and dust from adhering and accumulating on the surface of the third exhaust pipe 57. Then, the remaining of the film-forming gas and particles such as by-products and dust in the exhaust gas are removed by the by-product removal unit 62.
[0026]
In the present embodiment, the adhesion preventing gas 44 is heated to a predetermined temperature by the gas heating device 70. For example, when TEOS is formed, the temperature of the adhesion preventing gas 44 is set to 200 ° C. Since the heated anti-adhesion gas 44 flows through the buffer 46, the exhaust port 20, and the third exhaust pipe 57, it is possible to prevent the temperature of the exhaust gas from lowering. Generation can be prevented, and as a result, particles such as residual film forming gas, by-products, and dust can be more reliably prevented from adhering and accumulating.
[0027]
According to the embodiment, the following effects can be obtained.
[0028]
1) By inserting a cladding tube having an outflow port inside the first exhaust pipe connected to the exhaust port in the exhaust pipe system, thereby covering the inner peripheral surface of the cladding pipe and the exhaust port with the anti-adhesion gas. Since the exhaust gas can be prevented from contacting the inner peripheral surface of the cladding tube and the surface of the exhaust port, particles such as the residue of the film forming gas in the exhaust gas and by-products and dust adhere and deposit. Can be prevented.
[0029]
2) Prevents particles such as residual film-forming gas, by-products, and dust from adhering and accumulating near the exhaust port of the exhaust pipe system. As a result, it is possible to prevent a phenomenon of backflow into the processing chamber due to pressure fluctuations in the processing chamber during film formation, so that it is possible to prevent a decrease in the yield of the CVD apparatus and hence the IC manufacturing method.
[0030]
3) Reducing the rigor of maintenance of CVD equipment by preventing particles such as residual film forming gas, by-products, and dust from adhering and accumulating near the exhaust port of the exhaust pipe system. Therefore, the downtime of the operation of the CVD apparatus can be shortened, and the throughput of the CVD apparatus and thus the IC manufacturing method can be improved.
[0031]
4) Since the temperature of the exhaust gas can be prevented from lowering by heating the anti-adhesion gas to a predetermined temperature by the gas heating device, it is possible to prevent by-products from being generated by the exhaust gas. As a result, it is possible to more reliably prevent particles such as residual film forming gas, by-products, and dust from adhering and accumulating on the buffer, the exhaust port, and the third exhaust pipe.
[0032]
Note that the present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the gist of the present invention.
[0033]
For example, as the adhesion preventing gas, not only the nitrogen gas is used but also another inert gas, clean air of a clean room, or the like may be used.
[0034]
The cladding pipe is not limited to being installed in the first exhaust pipe connected to the exhaust port, but may be installed in an exhaust pipe in another stage of an exhaust pipe system such as a second exhaust pipe having a reducer.
[0035]
The cladding tube is not limited to having a telescope structure, but may have a porous tube structure or the like. Further, the outlet of the cladding tube is not limited to be formed by the gap or the clearance between the connecting portions of the segment rings, but may be formed by small holes or slits formed in the tube wall of the cladding tube.
[0036]
The present invention is not limited to the CVD apparatus, and can be applied to all semiconductor manufacturing apparatuses such as an oxide film forming apparatus, a diffusion apparatus, an annealing apparatus, and other heat treatment apparatuses.
[0037]
【The invention's effect】
As described above, according to the present invention, clogging of the exhaust pipe system can be effectively prevented.
[Brief description of the drawings]
FIG. 1 is a partially omitted side sectional view showing a CVD apparatus according to an embodiment of the present invention.
2A is a longitudinal sectional view of a main part, FIG. 2B is an enlarged sectional view of a part b of FIG. 2A, and FIG. 2C is an enlarged sectional view of a part c of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Wafer, 2 ... Casing, 10 ... CVD apparatus (semiconductor manufacturing apparatus), 11 ... Process tube, 12 ... Outer tube, 13 ... Inner tube, 14 ... Processing chamber, 15 ... Furnace port, 16 ... Manifold, 17 ... Partition wall, 18 Gas inlet pipe, 19 Exhaust passage, 20 Exhaust port, 21 Furnace opening / closing device, 22 Base, 23 Seal cap, 24 Rotating shaft, 25 Boat, 26, 27 End plate, 28 holding member, 29 holding groove, 30 heater unit, 31 resistance heater, 32 heat insulating tank, 40 exhaust pipe system, 41 first exhaust pipe, 42 upstream positioning section, 43 downstream positioning Reference numeral 44: Anti-adhesion gas, 45: Anti-adhesion gas introduction pipe, 46: Buffer, 47: Coating pipe, 48: Centering, 49: Flange part, 50: Seal ring, 51: Segment ring, 52, 53 Outflow port, 54 ... second exhaust pipe, 55 ... reducer part, 56 ... pipe joint part, 57 ... third exhaust pipe, 58 ... pipe joint part, 59 ... adhesion prevention gas introduction pipe, 60 ... fourth exhaust pipe, 61 ... pipe joint part, 62 ... by-product removal unit, 63 ... pipe joint part, 64 ... fifth exhaust pipe, 65 ... pipe joint part, 70 ... gas heating device, 71 ... film forming gas.

Claims (2)

An exhaust pipe having one end connected to the processing chamber for processing the substrate and the other end connected to an exhaust device is provided, and a coating pipe having an outflow port is inserted through a buffer inside the exhaust pipe, A semiconductor manufacturing apparatus, wherein an adhesion preventing gas is introduced into the buffer. 2. The semiconductor manufacturing apparatus according to claim 1, wherein the temperature of the adhesion preventing gas is heated to a temperature of the cladding tube capable of preventing by-products from adhering to the cladding tube. 3.

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