JP4954176B2 - Substrate heat treatment equipment - Google Patents

Description

  The present invention relates to a substrate heat treatment apparatus used for performing a CVD process, an oxidation process, a diffusion process, or the like on a surface of a plate-shaped workpiece such as a semiconductor wafer, that is, a substrate.

Conventionally, for example, a vertical heat treatment apparatus shown in FIG. 4 is used to perform a CVD process on the surface of a semiconductor wafer.
The heat treatment apparatus includes a vertical heat treatment furnace 100, a load space 110 provided below the heat treatment furnace 100, and a lift lift 120 for transporting the semiconductor wafer W (see, for example, Patent Document 1). ).

The heat treatment furnace 100 has a heater 101 and a process tube 103 made of quartz, and a furnace port 104 for taking the semiconductor wafer W into and out of the process tube 103 is provided at the bottom thereof. Yes. The furnace port 104 is closed by an opening / closing door 105 so as to be openable.
The process tube 103 includes an outer tube 103a and an inner tube 103b, and a gas supply pipe 106 for supplying a process gas is introduced into the inner tube 103b. The gas supply pipe 106 is provided in the state of being close to the peripheral wall of the inner tube 103b so as not to obstruct the carry-in and carry-out of the semiconductor wafer W.

The lifting / lowering lift 120 includes a boat 121 for holding the semiconductor wafer W. The semiconductor wafer W held on the boat 121 is carried into the process tube 103 from the load space 110, and at the same time, the process tube 103. It is carried out from the inside to the load space 110.
Further, the lift lift 120 is equipped with a heat barrier 122 composed of a plurality of quartz plates 122a. The heat barrier 122 reflects the heat in the process tube 103 upward, and Heat is prevented from escaping into the load space 110.

However, in the heat treatment apparatus, the effect of the heat barrier 122 is not sufficient, and the temperature near the furnace port 104 tends to decrease. For this reason, there is a problem that it takes time to raise the temperature of the semiconductor wafer W and the heat treatment time becomes long.
Therefore, an auxiliary heater for preventing a temperature drop near the furnace port is provided, and the distal end portion of the gas supply pipe is constituted by a tubular heater, and the process gas supplied from the gas supply pipe is heated, so that the heat treatment time is increased. Has been proposed (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 5-90186 JP-A-9-148315

  However, in any of the heat treatment apparatuses, since the atmosphere in the process tube is difficult to flow, the temperature distribution in the process tube becomes non-uniform and the gas supply pipe 106 is biased from the semiconductor wafer W. The process gas is supplied non-uniformly to the processing surface of the semiconductor wafer W in combination with the points arranged on the semiconductor wafer W. For this reason, there is a problem that the heat treatment tends to be non-uniform, such as the thickness of the CVD film generated on the processing surface of the semiconductor wafer varies.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a substrate heat treatment apparatus capable of performing heat treatment of a substrate such as a semiconductor wafer quickly and uniformly.

In order to achieve the above object, a substrate heat treatment apparatus according to the present invention includes a heat treatment furnace for heat treating a substrate carried into a process tube through a furnace opening provided at the bottom, and an open / close door that closes the furnace opening so as to be openable. And a load space provided below the heat treatment furnace, a lift for holding the substrate in a boat and carrying it into the process tube from the load space side through the furnace port, and carrying it out from the process tube to the load space; A substrate heat treatment apparatus comprising a gas supply means for supplying a process gas into the process tube, wherein the gas supply means is introduced into the process tube from the load space side through the furnace port by the lifting lift. A gas supply pipe, a heater for heating the process gas supplied from the gas supply pipe, It is location, and having a nozzle for blowing out a process gas heated by the heater upward, and a fan for convection process gas blown from the nozzle in the process tube.

  According to the substrate heat treatment apparatus having such a configuration, the process gas supplied from the gas supply pipe is heated by the heater and blown upward from the nozzle, and the blown process gas is convected in the process tube by the fan. be able to. For this reason, the substrate can be rapidly heated by the heated process gas. Further, since the temperature distribution and the process gas distribution in the process tube can be made uniform by the convection of the process gas, the substrate can be uniformly heat-treated.

  It is preferable that a plurality of the nozzles are arranged symmetrically with respect to the axis of the substrate held by the boat. Thereby, the process gas supplied from the gas supply pipe can be supplied more uniformly to the substrate, and thus the substrate can be heat-treated more uniformly.

It is preferable that the gas supply pipe is provided coaxially with respect to the axis of symmetry of the nozzle in a state where the opening / closing door is inserted. Thereby, since process gas can be supplied to each nozzle from the symmetrical axis part of each nozzle, it can suppress that the supply amount of process gas to each nozzle varies. For this reason, the substrate can be heat-treated more uniformly.
The rotation shaft of the fan is preferably inserted through the gas supply pipe. In this case, the fan can be easily driven to rotate.

  In the substrate heat treatment apparatus, a hollow flange portion is provided at an upper end portion of the gas supply pipe, a process gas introduction space is formed inside the flange portion, and the flange portion is in communication with the introduction space. It is preferable that the plurality of nozzles are formed at the upper end portion, and the heater is arranged facing the introduction space. In this case, the process gas can be easily and efficiently heated by the heater, and a plurality of nozzles can be easily formed.

  A heat reflecting plate is preferably provided inside the flange portion so as to face the lower surface of the heater. In this case, since the heat of the heater can be reflected upward by the heat reflecting plate, the process gas can be heated more effectively.

  According to the substrate heat treatment apparatus of the present invention, the substrate can be rapidly heated by the heated process gas, and the temperature distribution in the process tube and the distribution of the process gas can be made uniform. Heat treatment can be performed quickly and uniformly.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic longitudinal sectional view showing a substrate heat treatment apparatus according to an embodiment of the present invention.
This heat treatment apparatus is provided with a heat treatment furnace 2 for performing heat treatment on a semiconductor wafer (substrate) W inside a housing 1, and a load space 3 is provided below the heat treatment furnace 2. A transfer space A for transferring the semiconductor wafer W to the load space 3 is provided. The load space 3 and the conveyance space A do not necessarily need to be closed spaces, and include cases where they are open spaces.

  The heat treatment furnace 2 is a vertical type in which a heater 21 is disposed around a quartz process tube 22 having an open bottom. The process tube 22 has a cylindrical inner tube 22b disposed inside an outer tube 22a having a dome-shaped ceiling. At the bottom of the heat treatment furnace 2, a furnace port 23 is provided for carrying the semiconductor wafer W into and out of the process tube 22. A space between the peripheral wall of the outer tube 22a and the peripheral wall of the inner tube 22b is configured as a process gas exhaust path.

  Inside the load space 3, a boat 4 for holding the semiconductor wafers W is arranged, and a lifting lift 5 for introducing the boat 4 into the process tube 22 of the heat treatment furnace 2 is arranged. Yes. The boat 4 horizontally holds a plurality of semiconductor wafers W with a gap therebetween, and is supported by a lifting table 51 provided on the lifting lift 5 through a frame (not shown).

The elevating table 51 is coupled to a plurality of pairs of ball screws 53 erected in the load space 3 via ball nuts 54. The elevating table 51 can be moved up and down by rotationally driving the ball screw 53 by the rotation drive mechanism 55, whereby the semiconductor wafer W held in the boat 4 can be carried into the process tube 22, It can be carried out from within the process tube 22.
The elevating table 51 also serves as an open / close door that closes the furnace port 23 of the heat treatment furnace 2 at its rising end and opens the furnace port 23 as it descends.

  A heat barrier 52 is provided above the lifting table 51. The heat barrier 52 is formed by stacking a plurality of stages of disk-shaped reflecting plates 52 a made of quartz with a predetermined gap, and reflects the radiant heat in the process tube 22 upward so that the radiant heat is transferred to the load space 3. The transmission is suppressed.

  A gas supply means 6 for supplying a process gas into the process tube 22 is mounted on the lift 5. This gas supply means 6 is provided directly under the boat 4, and a metal or quartz gas supply pipe 61 that passes through the lifting table 51 and the heat barrier 52, and a process gas supplied through the gas supply pipe 61. 2, a plurality of nozzles 63 for blowing process gas heated by the heater upward, and a fan 64 for convection of the process gas blown upward (see FIG. 2).

  A flexible tube (not shown) is connected near the lower end portion of the gas supply pipe 61 located in the load space 3 so that the gas supply pipe 61 can be lifted and lowered together with the lifting table 51. The axis L2 of the gas supply pipe 61 and the axis L1 of the semiconductor wafer W held by the boat 4 are located on the same line (see FIG. 1).

  The heater 62 and the nozzle 63 are provided in a flange portion 65 connected to the upper end portion of the gas supply pipe 61. The flange portion 65 has a hollow disk shape, and is provided coaxially with the axis L <b> 2 of the gas supply pipe 61. A gas introduction space 67 for introducing a process gas from the gas supply pipe 61 is formed inside the flange portion 65. The gas introduction space 67 is formed so as to face the top plate 66, and the disk-shaped heater 62 is arranged in a state of facing the gas introduction space 67. The process gas introduced into the gas introduction space 67 can be heated by the heater 62. For this reason, it is possible to prevent the semiconductor wafer W from being cooled by the process gas, and as a result, the semiconductor wafer W can be rapidly heated to the processing temperature. As the heater 62, a quartz heater, a ceramic heater, or the like can be used.

A gap 70 is provided between the heater 62 and the bottom plate 69 of the flange portion 65, and the gap 70 and the gas introduction space 67 are partitioned by the heater 62 while maintaining hermeticity.
A disc-shaped heat reflecting plate 71 is provided on the inner bottom portion of the flange portion 65 so as to face the lower surface of the heater 62. The heat reflecting plate 71 is made of, for example, molybdenum or platinum. Thereby, the heat of the heater 62 is reflected upward, and the process gas can be heated more effectively.

  The heater 62 is supplied with electric power through a power supply portion 62 a provided outside the outer periphery of the gas supply pipe 61. Further, the gas supply pipe 61 and the power feeding part 62 a are surrounded by a quartz pipe 68 that passes through each reflection plate 52 a of the heat barrier 52.

Each nozzle 63 includes a through hole formed in the top plate 66 and communicates with the gas introduction space 67 of the flange portion 65. Each nozzle 63 is arranged symmetrically with respect to the axis L 1 of the semiconductor wafer W held in the boat 4 and the axis L 2 of the gas supply pipe 61. FIG. 3 is a plan view showing an example of the arrangement form of the nozzles 63. A plurality of nozzles 63 are arranged on the axis L1 for each concentric circle along a plurality of concentric circles about the symmetry axis Q coincident with the axis L2. They are arranged at predetermined intervals so as to be axially symmetric.
Thus, by forming the hollow flange portion 65 at the upper end of the gas supply pipe 61 and providing the gas introduction space 67 and the heater 62 therein, the process gas can be easily and efficiently heated by the heater 62. In addition, the plurality of nozzles 63 can be easily formed with axial symmetry.

  The fan 64 is disposed above the top plate 66 of the flange portion 65, and with the rotation, the process gas blown out from each nozzle 63 is blown upward to forcibly convection in the process tube 22. A rotation shaft 64 a of the fan 64 passes through the inside of the gas supply pipe 61 concentrically with the axis L <b> 2 of the gas supply pipe 61. A gap between the rotating shaft 64a of the fan 64 and the inner periphery of the gas supply pipe 61 is appropriately sealed at the lower end of the gas supply pipe 61 by a magnetic seal (not shown). The lower end of the rotary shaft 64a is connected to a rotary drive device (not shown) mounted on the lift lift 5. Thus, by inserting the rotation shaft 64a into the gas supply pipe 61, the fan 64 can be easily rotated.

  Inside the transfer space A, a cassette stocker and a transfer robot are arranged (not shown). By this transfer robot, the semiconductor wafer W is transferred from the cassette stocker to the boat 4 through a door (not shown). It can be transferred or taken out from the boat 4 to the transport space A.

  The heat treatment apparatus having the above-described configuration lowers the lift lift 5 to the load space 3 and raises the lift lift 5 with a plurality of semiconductor wafers W transferred from the transfer space A to the boat 4. The semiconductor wafer W is introduced into the process tube 22 together with the boat 4 through 23. Simultaneously with the introduction of the semiconductor wafer W, the furnace port 23 is closed by the lifting table 51 and the process tube 22 is sealed, and in this state, the semiconductor wafer W is subjected to a heat treatment such as a CVD process.

  During this heat treatment, the process gas is continuously supplied to the semiconductor wafer W by the gas supply means 6. At this time, the semiconductor wafer W can be rapidly heated by the heated process gas. Further, since the process gas blown out from each nozzle 63 can be forcedly convected by the fan 64, the temperature distribution and the process gas distribution in the process tube 22 can be made uniform. As a result, the semiconductor wafer can be uniformly heat-treated.

  In addition, since the nozzles 63 directly below the boat 4 are arranged symmetrically with respect to the axis L1 of the semiconductor wafer W held in the boat 4, the process gas supplied from the gas supply pipe 61 is transferred to the semiconductor. The wafer W can be supplied axially symmetrically. For this reason, the process gas can be supplied uniformly to the processing surface of the semiconductor wafer W, and as a result, the heat treatment can be performed more uniformly.

  In particular, in the embodiment described above, the symmetry axis Q of each nozzle 63 and the axis L2 of the gas supply pipe 61 coincide with each other, so that the process gas is diffused radially from the center of the gas introduction space 67 and the nozzle 63 Can lead to. For this reason, it can suppress that the quantity of the process gas supplied to each nozzle 62 varies. As a result, the semiconductor wafer W can be heat-treated more uniformly.

  When the heat treatment of the semiconductor wafer W is completed, the lift lift 5 is driven to lower the semiconductor wafer W together with the boat 4 to the load space 3 and cool it. When the semiconductor wafer W is cooled to a predetermined temperature, the semiconductor wafer W is transferred to the transfer space A by the transfer robot. Thus, one heat treatment cycle is completed.

  The substrate heat treatment apparatus according to the present invention is not limited to the above embodiment. For example, the object to be heat-treated is not limited to the semiconductor wafer W, but may include various plate-like workpieces, that is, substrates. Further, the boat may be one that supports the substrate in a standing state in addition to one that supports the substrate in a horizontal state. Furthermore, the heat barrier 52 is configured as necessary.

It is a schematic longitudinal cross-sectional view which shows the heat processing apparatus of the board | substrate which concerns on one Embodiment of this invention. It is an expanded sectional view of a nozzle part. It is a top view which shows an example of the arrangement form of a nozzle. It is a schematic longitudinal cross-sectional view which shows the conventional heat processing apparatus.

Explanation of symbols

2 Heat treatment furnace 22 Process tube 23 Furnace port 3 Load space 4 Boat 5 Lifting lift 51 Lifting table (opening / closing door)
6 Gas supply means 62 Heater 63 Nozzle 64 Fan 64a Rotating shaft of fan 65 Flange portion 67 Gas introduction space 71 Heat reflection plate W Semiconductor wafer (substrate)
L1 Axis of semiconductor wafer (substrate) L2 Axis of gas supply pipe Q Axis of symmetry of nozzle

Claims (6)

A heat treatment furnace for heat-treating the substrate carried into the process tube through a furnace port provided at the bottom;
An open / close door that closes the furnace port in an openable manner;
A load space provided below the heat treatment furnace;
The substrate is held by a boat and carried into the process tube from the load space side through the furnace port, and a lifting lift to be carried out from the process tube to the load space;
A substrate heat treatment apparatus comprising gas supply means for supplying a process gas into the process tube,
The gas supply means;
A gas supply pipe introduced into the process tube from the load space side through the furnace port by the lifting lift;
A heater for heating the process gas supplied from the gas supply pipe;
A nozzle that is disposed immediately below the boat and blows upward the process gas heated by the heater;
A substrate heat treatment apparatus, comprising: a fan for convection of process gas blown from the nozzle in a process tube.   The substrate heat treatment apparatus according to claim 1, wherein a plurality of the nozzles are arranged symmetrically with respect to an axis of the substrate held by the boat.   The substrate heat treatment apparatus according to claim 2, wherein the gas supply pipe is provided coaxially with respect to an axis of symmetry of the nozzle in a state in which the opening / closing door is inserted.   The substrate heat treatment apparatus according to claim 3, wherein a rotation shaft of the fan is inserted through the inside of the gas supply pipe.   A hollow flange portion is provided at an upper end portion of the gas supply pipe, a process gas introduction space is formed inside the flange portion, and the plurality of nozzles are provided at the upper end portion of the flange portion in a state of communicating with the introduction space. The substrate heat treatment apparatus according to claim 3, wherein the heater is disposed so as to face the introduction space.   6. The substrate heat treatment apparatus according to claim 5, wherein a heat reflecting plate is provided inside the flange portion so as to face the lower surface of the heater.

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