JP4399279B2 - Substrate processing apparatus and IC manufacturing method - Google Patents

Description

  The present invention relates to a substrate processing apparatus that accommodates a substrate in a processing chamber and performs processing under heating. For example, the present invention relates to a semiconductor wafer (hereinafter referred to as a wafer) in which a semiconductor integrated circuit device (hereinafter referred to as an IC) is fabricated. The present invention relates to an effective heat treatment apparatus (furnace) used for thermal treatment such as annealing, reflow, oxidation, diffusion, and film formation by thermal CVD reaction.

In an IC manufacturing method, a batch type vertical hot wall type annealing apparatus, which is an example of a heat treatment apparatus, is widely used for annealing a wafer. A batch type vertical hot wall type annealing apparatus (hereinafter referred to as an annealing apparatus) includes a process tube that forms a processing chamber and is installed vertically, an exhaust pipe that exhausts the processing chamber, and a gas supply pipe that supplies gas to the processing chamber Are connected to each other, a heater unit that is installed outside the process tube and heats the processing chamber, and a boat that holds a plurality of wafers aligned in the vertical direction and carries them into the processing chamber. When a boat holding a plurality of wafers is loaded into the processing chamber from the bottom furnace port (boat loading), annealing gas is supplied from the gas supply pipe to the processing chamber, and the processing chamber is heated by the heater unit. The wafer is annealed (see, for example, Patent Document 1).
JP 2003-324106 A

As a conventional annealing apparatus, there is one in which a process tube is formed of silicon carbide (SiC) and a manifold is formed of transparent quartz. Since the transparent quartz manifold has a sealing surface made of transparent quartz with a silicon carbide process tube, aluminum oxide (Al ₂ O) is used on the outer periphery of the transparent quartz manifold to prevent transmission of radiant heat. _A heat insulation cloth consisting of ₃ ) is wound.

  However, in the above-described annealing apparatus, since the main component of the heat insulating cloth is heavy metal, there is a problem that metal contamination occurs in the annealed wafer.

  An object of the present invention is to provide a substrate processing apparatus capable of preventing the occurrence of metal contamination.

A substrate processing apparatus according to the present invention is provided under a process tube made of silicon carbide forming a processing chamber for processing a substrate, a heater unit for heating the substrate in the processing chamber to 1200 ° C. or more, and the process tube. And a metal seal cap that closes the lower end opening of the manifold. At least a part of the manifold on the process tube side is formed of opaque quartz, and fixes the manifold. The holding ring is provided with a cooling mechanism, the seal cap is provided with a cooling mechanism, and the process tube side main surface of the seal cap is covered with a quartz cover. To do.
Among the other inventions disclosed in the present application, representative ones are as follows.
A double annular groove is laid on the sealing surface of the manifold with the process tube, the inner annular groove is evacuated, and the outer annular groove is supplied with processing gas. A substrate processing apparatus.

  According to the present invention, since the manifold is made of opaque quartz, it is possible to prevent the transmission of radiant heat, so that the heat insulating cloth that causes metal contamination can be eliminated. By eliminating the heat insulating cloth, occurrence of metal contamination can be prevented.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  In the present embodiment, the substrate processing apparatus according to the present invention is configured as an annealing apparatus (batch type vertical hot wall annealing apparatus) for performing an annealing step in an IC manufacturing method. As shown in FIGS. 1 and 2, the annealing apparatus 10 includes a housing 11 formed in a substantially rectangular parallelepiped box shape. A cassette stage 12 is installed inside the front wall of the housing 11, and a cassette 2 for storing and transferring the wafer 1 is supplied to the cassette stage 12 by an in-process transfer device (not shown). ing. A cassette elevator 13 as an elevating means is provided on the rear side of the cassette stage 12 inside the housing 11, and a cassette transfer device 14 as a conveying means is attached to the cassette elevator 13. A cassette shelf 15 for storing the cassette 2 is provided on the rear side of the cassette elevator 13, and a spare cassette shelf 16 is provided above the cassette stage 12. A clean unit 17 is provided above the spare cassette shelf 16, and the clean unit 17 is configured to distribute clean air inside the housing 11. A transfer elevator 18 is installed vertically on the rear side of the cassette shelf 15 inside the housing 11, and a wafer transfer device 19 for transferring the wafer 1 is installed in the transfer elevator 18.

  A boat elevator 20 constructed by a motor-driven feed screw shaft device or the like is installed on the rear side of the transfer elevator 18 inside the housing 11, and an arm 22 and a seal are provided on a lift 21 of the boat elevator 20. The boat 23 is supported via a cap or the like. The boat 23 includes a pair of end plates 24 and 25 at the top and bottom, and a plurality of holding members 26 arranged vertically between the both end plates 24 and 25, and each holding member 26 has a plurality of holding grooves. 27 are arranged at equal intervals in the longitudinal direction so as to be opened in the same plane. The wafer 1 is held in the boat 23 by being aligned in a state where the centers are aligned with each other horizontally by inserting the outer peripheral portion between the plurality of holding grooves 27. A heat insulating cap 28 is formed on the lower side of the boat 23.

  A heater unit 30 is installed vertically above the housing 11 so that the center line is vertical. A process tube 31 is installed concentrically inside the heater unit 30. The process tube 31 is made of silicon carbide and is formed in a cylindrical shape whose upper end is closed and whose lower end is opened. A circular ring-shaped flange portion 32 is horizontally provided at the lower end of the outer periphery of the process tube 31. ing. The cylindrical hollow portion of the process tube 31 forms a processing chamber 33 into which a plurality of wafers held by the boat 23 are loaded. The inner diameter of the process tube 31 forming the processing chamber 33 is the maximum outer diameter of the wafer to be handled. It is set to be larger than (for example, 300 mm).

  A support ring 35 is horizontally suspended below the process tube 31 of the housing 11 via a lifting tool 34, and the support ring 35 supports the manifold 40 from below. As shown in FIG. 3, a holding ring 36 that holds the manifold 40 is mounted on the support ring 35. A cooling water channel 37 is laid concentrically inside the holding ring 36, and cooling water is passed through the cooling water channel 37. The manifold 40 is made of opaque quartz and is formed in a short, substantially cylindrical shape with both upper and lower ends opened, and a furnace port 41 is formed by the lower end opening of the manifold 40. A circular ring-shaped flange portion 42 protrudes horizontally at the lower end of the outer periphery of the manifold 40. The support ring 35 supports the manifold 40 and the process tube 31 by engaging with the peripheral edge of the lower end surface of the flange portion 42 from below. The holding ring 36 is in contact with the upper surface of the flange portion 42 of the manifold 40, thereby forcibly cooling the manifold 40 with cooling water flowing through the cooling water flow path 37.

  As shown in FIG. 3, the lower end surface of the flange portion 32 of the process tube 31 is in contact with the upper end surface of the manifold 40, and the process tube 31 is supported vertically on the manifold 40. It has become. A sealing gas circulation groove 43 for circulating a sealing gas is laid concentrically on the sealing surface with the process tube 31 which is the upper end surface of the manifold 40, and the gas introduction pipe 44 is disposed in the sealing gas circulation groove 43. Is connected. As the sealing gas 45, the same gas as the processing gas is used. A vacuum groove 46 is concentrically laid outside the sealing gas flow groove 43 on the upper end surface of the manifold 40, and a vacuum pipe 47 is connected to the vacuum groove 46.

  As shown in FIG. 2, a large-diameter exhaust pipe 48 whose other end is connected to a vacuum exhaust device (not shown) is connected to the side wall of the manifold 40 so as to communicate with the processing chamber 33. The exhaust pipe 48 exhausts the processing chamber 33. A gas supply pipe 49 is connected to the other side wall of the manifold 40 so as to communicate with the processing chamber 33, and the other end of the gas supply pipe 49 is connected to a gas supply device (not shown) for supplying an annealing gas. It is connected.

  As shown in FIGS. 1 and 2, a shutter 50 that opens and closes the furnace port 41 is installed in the vicinity of the manifold 40 inside the housing 11. The shutter 50 is carried out from the processing chamber 33 by the boat 23. The furnace port 41 is configured to be closed when being operated. When the boat 23 is carried into the processing chamber 33, the furnace port 41 is configured to be closed by a seal cap 51. The seal cap 51 is made of a metal material such as stainless steel and is formed in a disk shape having a larger diameter than the furnace port 41. A cooling water flow path 52 is laid in a meandering shape inside the seal cap 51, and cooling water is circulated through the cooling water flow path 52.

A cover 53 formed of quartz (SiO ₂ ) is attached to the upper surface of the seal cap 51, and a seal ring housing groove 54 is concentrically disposed on the peripheral edge of the upper surface of the cover 53. A storage ring 54 stores a seal ring 55 that seals the furnace port 41.

  Next, an annealing process by the annealing apparatus according to the above configuration will be described.

  The cassette 2 loaded with the wafer 1 is loaded into the cassette stage 12 by the in-process transfer device in an upward posture, and is rotated 90 degrees by the cassette stage 12 so that the wafer 1 is in a horizontal posture. Further, the cassette 2 is transported from the cassette stage 12 to the cassette shelf 15 or the spare cassette shelf 16 by cooperation of the raising / lowering operation of the cassette elevator 13, the transverse operation, the advance / retreat operation of the cassette transfer device 14, and the rotation operation. The cassette shelf 15 is provided with a transfer shelf in which the cassette 2 to be transferred by the wafer transfer device 19 is stored. The cassette 2 to which the wafer 1 is transferred is the cassette elevator 13 and the cassette transfer device. 14 is transferred to the transfer shelf.

  When the cassette 2 is transferred to the transfer shelf, the wafer 1 is transferred from the transfer shelf to the boat 23 by the cooperation of the advance / retreat operation, the rotation operation of the wafer transfer device 19 and the raising / lowering operation of the transfer elevator 18. The The plurality of wafers 1 are loaded (wafer charging) by the wafer transfer device 19 in a state where the center lines are aligned parallel to each other on the boat 23.

  When a predetermined number of wafers 1 are loaded, the boat 23 is loaded into the processing chamber 33 from the furnace port 41 of the manifold 40 (boat loading) as the seal cap 51 is lifted by the boat elevator 20, and FIG. As shown in the figure, it remains in the processing chamber 33 while being supported by the seal cap 51. In this state, the seal cap 51 is in a state of hermetically sealing the furnace port 41. That is, when the seal ring 55 at the peripheral edge of the cover 53 attached to the seal cap 51 is in close contact with the lower end surface of the manifold 40, the furnace port 41 is hermetically sealed.

  Subsequently, the inside of the process tube 31 is exhausted by the exhaust pipe 48 to a predetermined degree of vacuum (several tens to several tens of thousands Pa). Further, the inside of the process tube 31 is uniformly heated to a predetermined temperature (1200 ° C. or more) by the heater unit 30. At this time, the cooling water flows through the cooling water flow path 37 of the holding ring 36 and the cooling water flow path 52 of the seal cap 51, respectively, and the manifold 40 and the seal cap 51 are cooled to maintain their temperatures at predetermined values. When the temperature and pressure inside the process tube 31 are stabilized, an annealing gas such as argon (Ar) is supplied to the processing chamber 33 through the gas supply pipe 49.

  When a preset processing time elapses, the seal cap 51 is lowered to open the furnace port 41, and the group of wafers is held from the furnace port 41 and directly below the process tube 31 while being held in the boat 23. The boat is unloaded (boat unloading). When the boat 23 is carried out, the shutter 50 hermetically seals the furnace port 41.

  The processed wafer 1 is transferred from the boat 23 to the cassette 2 of the transfer shelf by the reverse procedure of the operation described above, and the cassette 2 is transferred from the transfer shelf to the cassette stage 12 by the cassette transfer device 14. It is carried out of the casing 11 by the in-process transfer device.

  By the way, in the above annealing process, since the processing temperature is heated to 1200 ° C. or more, the escape of heat from the manifold 40 becomes large. However, in the present embodiment, since the manifold 40 is made of opaque quartz, escape of heat from the manifold 40 can be suppressed. That is, since the opaque quartz is produced by forming bubbles in the transparent quartz, the heat rays incident on the manifold 40 are prevented from escaping to the outside by irregular reflection in the bubbles. Therefore, it is not necessary to lay a heat insulating cloth on the outer periphery of the manifold 40 to prevent the heat rays from being reflected and escape. As a result, it is possible to avoid the occurrence of metal contamination due to the heavy metal of the heat insulating cloth passing through the manifold 40.

  Here, since the opaque quartz is produced by forming bubbles in the transparent quartz, the gas circulation groove 43 for sealing is formed on the sealing surface with the process tube 31 of the manifold 40 made of opaque quartz by polishing or cutting. When formed, the bubbles are crushed to form an uneven surface, and a fine communication path is formed on the surface of the sealing gas flow groove 43. Therefore, the sealing surface between the manifold 40 and the process tube 31 is hermetically sealed. Can not do it. It is generally considered to lay a seal ring outside the sealing gas flow groove 43 on the sealing surface between the manifold 40 and the process tube 31. However, since the sealing surface between the manifold 40 and the process tube 31 becomes extremely high temperature, the seal ring cannot be used.

  In the present embodiment, the vacuum groove 46 is laid outside the sealing gas flow groove 43 to secure an airtight seal between the manifold 40 and the process tube 31 by the sealing gas flow groove 43. That is, since the pressure in the sealing gas flow groove 43 is higher than the pressure in the processing chamber 33, it is possible to prevent the atmosphere such as the annealing gas in the processing chamber 33 from leaking to the outside of the processing chamber 33. Since the sealing gas 45 leaked from the sealing gas flow groove 43 is sucked and captured by the vacuum groove 46, it is prevented from leaking outside the processing chamber 33. Even if the sealing gas 45 in the sealing gas circulation groove 43 leaks into the processing chamber 33, the same gas as the annealing gas (for example, argon gas) is used as the sealing gas. Occurrence of adverse effects in the annealing process due to leakage into the processing chamber 33 can be prevented. In this manner, according to the present embodiment, an airtight seal between the manifold 40 and the process tube 31 can be ensured, so that the manifold 40 can be formed of opaque quartz.

By the way, quartz is easy to permeate metal, whereas silicon carbide can suppress the permeation of metal (one thousandth of quartz). Therefore, it is generally considered that the manifold 40 is formed of silicon carbide. However, since the manifold 40 cannot be formed of silicon carbide for the following reasons, the manifold 40 needs to be formed of quartz.
1) Since silicon carbide has a high thermal conductivity, when the manifold 40 is formed of silicon carbide, the seal ring that seals between the contact surfaces of the manifold 40 and the seal cap is melted by heat.
2) Since silicon carbide has a high coefficient of thermal expansion, and the manifold 40 is arranged in a region not heated by the heater unit 30, the temperature gradient becomes extremely large. Therefore, when the manifold 40 is formed of silicon carbide. Will cause the manifold 40 to crack.

  In the present embodiment, the seal cap 51 is made of metal, but the upper surface of the seal cap 51 is covered with the cover 53 made of quartz, so that the metal surface is not exposed to the processing chamber 33. Here, quartz is relatively easy to permeate metal (several thousand times that of silicon carbide), but the seal cap 51 can prevent the metal from permeating through the cooling water channel 52 (for example, 200 to 250). Therefore, the metal contamination of the processing chamber 33 due to the permeation of the metal component of the seal cap 51 through the cover 53 can be prevented.

  According to the embodiment described above, the following effects can be obtained.

1) Since the manifold is made of opaque quartz, the escape of heat from the manifold can be prevented, so that the installation of the heat insulating cloth on the outer periphery of the manifold can be omitted. As a result, it is possible to prevent metal contamination of the processing chamber due to permeation of the heavy metal manifold of the heat insulating cloth.

2) By laying the vacuum groove outside the sealing gas flow groove, it is possible to secure an airtight seal between the manifold and the process tube by the sealing gas flow groove, so the manifold can be made of opaque quartz. it can.

3) By using the same gas as the annealing gas (for example, argon gas) as the sealing gas that flows through the sealing flow groove, even if the sealing gas in the sealing gas flow groove leaks into the processing chamber The occurrence of adverse effects in the annealing process due to leakage of the sealing gas into the processing chamber can be prevented.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  For example, the entire manifold is not limited to being formed of opaque quartz, and a part of the process tube side may be formed of opaque quartz.

  The gas flow groove for sealing and the groove for vacuum are not limited to be provided on the manifold side, but may be provided on the process tube side or both.

  The process tube is not limited to being formed of silicon carbide, but may be formed of silicon carbide and a silicon impregnated material.

  The present invention is not limited to an annealing apparatus, and can be applied to any substrate processing apparatus that is also used for oxidation processing, diffusion processing, film formation processing by thermal CVD reaction, and the like.

  In the above embodiment, the case where the wafer is processed has been described. However, the processing target may be a photomask, a printed wiring board, a liquid crystal panel, a compact disk, a magnetic disk, or the like.

1 is a partially omitted perspective view showing an annealing apparatus according to an embodiment of the present invention. It is side surface sectional drawing. It is sectional drawing which shows the principal part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Wafer (substrate to be processed), 2 ... Cassette, 10 ... Annealing apparatus (substrate processing apparatus), 11 ... Housing, 12 ... Cassette stage, 13 ... Cassette elevator, 14 ... Cassette transfer device, 15 ... Cassette shelf, DESCRIPTION OF SYMBOLS 16 ... Reserve cassette shelf, 17 ... Clean unit, 18 ... Transfer elevator, 19 ... Wafer transfer device, 20 ... Boat elevator, 21 ... Lifting platform, 22 ... Arm, 23 ... Boat, 24, 25 ... End plate, 26 DESCRIPTION OF SYMBOLS ... Holding member, 27 ... Holding groove, 28 ... Heat insulation cap, 30 ... Heater unit, 31 ... Process tube, 32 ... Flange part, 33 ... Processing chamber, 34 ... Suspension tool, 35 ... Support ring, 36 ... Holding ring, 37 ... Cooling water flow path, 40 ... Manifold, 41 ... Furnace port, 42 ... Flange part, 43 ... Gas flow groove for sealing, 44 ... Gas introduction pipe, 45 ... Gas for sealing, 6 ... Vacuum groove, 47 ... Vacuum pipe, 48 ... Exhaust pipe, 49 ... Gas supply pipe, 50 ... Shutter, 51 ... Seal cap, 52 ... Cooling water flow path, 53 ... Cover, 54 ... Seal ring storage groove, 55 ... Seal ring.

Claims (2)

A process tube forming a processing chamber for processing a substrate;
A heater unit for heating the substrate in the processing chamber;
A manifold that is disposed under the process tube and at least a part of the process tube side is formed of opaque quartz ;
A seal cap for closing the lower end opening of the manifold ;
A gas supply pipe for supplying a processing gas to the processing chamber;
Laid on the sealing surface between the process tube which is the upper end surface of the manifold, and Cie Lumpur gas passage grooves by flowing a sealing gas,
A gas introduction pipe for supplying the same gas as the processing gas to the sealing gas flow groove so that the pressure in the sealing gas flow groove is higher than the pressure in the processing chamber;
Is laid on the outer side of the seal gas flow channel of the seal surface, and Luba Kyumu groove to suck the same gas and the process gas leaked from the seal gas passage grooves,
Substrate processing apparatus, characterized in that it comprises a.   A step of carrying a substrate into a processing chamber formed by a process tube and closing a lower end opening of a manifold, which is disposed under the process tube and at least a part of the process tube side is made of opaque quartz, with a seal cap When,
  The process gas is supplied from the gas supply pipe to the process chamber, and the same gas as the process gas is supplied from the gas introduction pipe to the seal gas flow groove provided on the seal surface with the process tube which is the upper end surface of the manifold. Gas from the vacuum groove laid outside the sealing gas flow groove on the sealing surface while supplying the gas in the sealing gas flow groove to be higher than the pressure in the processing chamber. Sucking the
  An IC manufacturing method comprising:

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