JP4155849B2 - Substrate processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate processing apparatus, and more particularly to a technology for transferring a boat to a processing chamber. For example, diffusion, CVD, epitaxial growth, or the like on a semiconductor wafer (hereinafter referred to as a wafer) on which a semiconductor integrated circuit including semiconductor elements is fabricated. The present invention relates to an effective heat treatment apparatus (furnace) for performing a thermal treatment. In particular, the present invention relates to an effective device for use in an apparatus for silicon epitaxial growth or silicon germanium epitaxial growth performed at a low temperature of 400 to 700 ° C.
[0002]
[Prior art]
As a heat treatment apparatus for performing heat treatment on wafers, a process tube in which a treatment chamber for heat treatment is formed in a state where a plurality of wafers are held in a boat, and a boat that is formed directly below the process tube and is carried into and out of the treatment chamber. 2. Description of the Related Art A batch type vertical hot wall heat treatment apparatus including a standby chamber for waiting and a boat elevator that lifts and lowers a boat and carries it in and out of the processing chamber is widely used. In the conventional batch type vertical hot wall type heat treatment apparatus, the boat elevator is constituted by a feed screw shaft device and is installed vertically in the standby chamber, and the lower end of the feed screw shaft is supported in the standby chamber and the standby chamber at the upper end. The motor is rotated by a motor installed outside.
[0003]
In such a batch type vertical hot wall type heat treatment apparatus, since the boat elevator is installed inside the waiting room, organic substances are scattered from grease, wiring cables, etc. used in the feed screw shaft apparatus and the guide rail. As a result, there is a problem that the wafer is contaminated. When the boat heated to a high temperature is lowered into the standby chamber and the temperature of the standby chamber rises, the amount of evaporation of the organic substance increases. For this reason, after the heat treatment in the processing chamber is completed, the boat or wafer group is cooled to a temperature of, for example, 100 ° C. or less while the board is left in the processing chamber, and the temperature of the boat or wafer group is sufficiently lowered, The boat is carried out from the processing chamber.
[0004]
However, if the boat is unloaded from the processing chamber after the temperature of the boat or wafer group has been sufficiently lowered, the throughput of the batch type vertical hot wall heat treatment apparatus is lowered. Therefore, the boat elevator is installed outside the waiting room, the nut and the boat screwed up and down to the feed screw shaft of the boat elevator are connected by the lifting shaft, and the bellows is provided between the lifting shaft and the waiting room. A batch type vertical hot wall type heat treatment apparatus that prevents scattering of organic substances from a boat elevator by hermetically sealing with a water jet is proposed (for example, see Patent Document 1).
[0005]
[Patent Document 1]
JP-A-6-120159 gazette
[Problems to be solved by the invention]
However, in the batch type vertical hot wall heat treatment apparatus in which the boat elevator is installed outside the waiting room and hermetically sealed by the bellows, organic contamination can be prevented, but the problem is that the boat elevator becomes large. is there. In addition, a seal ring is generally used to maintain a hermetic seal between the seal cap and the processing chamber. In order to reduce the crushing rate of the seal ring to 8% or more, for example, the seal cap is about 10 N. It is necessary to push up with the power of. When the boat elevator is installed outside the waiting room, the moment acting on the boat elevator increases, so that the mechanical strength of each component of the boat elevator needs to be set large.
[0007]
The objective of this invention is providing the substrate processing apparatus which can prevent the contamination by a boat elevator, avoiding enlargement.
[0008]
[Means for Solving the Problems]
The substrate processing apparatus according to the present invention includes a processing chamber that performs processing while holding a plurality of substrates in a boat, a standby chamber connected to the processing chamber, and the processing chamber and the standby by moving the boat. In a substrate processing apparatus provided with a boat elevator that carries in and out of a chamber,
The boat elevator includes a guide rail and a feed screw shaft that are inserted into an insertion hole formed in the standby chamber so as to extend in and out of the standby chamber, and an outer side of the standby chamber of the guide rail and the feed screw shaft. A motor part installed at one end of the motor, a guide block in which the guide rail is slidably inserted and fixed in the standby chamber, and the feed screw shaft fixed to the guide block and rotated by the motor is screwed. And a fitted nut.
[0009]
According to the above-described means, by fixing the nut of the feed screw shaft device constituting the boat elevator and raising and lowering the feed screw shaft, the boat can be lifted and lowered directly by the feed screw shaft. The number of parts can be reduced. Since the distance in the horizontal direction of the load center when hermetic sealing is carried into the processing chamber of the boat can be shortened, and the vertical distance between the support point of the guide rail and the load can also be shortened, the boat The mechanical strength or rigidity of each component of the elevator can be set small, and the initial cost and running cost of the boat elevator and thus the substrate processing apparatus can be greatly reduced.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0011]
In the present embodiment, a substrate processing apparatus according to the present invention is configured as a batch type vertical hot wall type heat treatment apparatus (hereinafter referred to as a batch type heat treatment apparatus) for performing a heat treatment on a wafer in a method for manufacturing a semiconductor device. Yes.
[0012]
As shown in FIG. 1, the batch heat treatment apparatus 10 includes a housing 11, and a cassette transfer unit 12 is installed on the front surface of the housing 11. The cassette transfer unit 12 includes a cassette stage 13 on which two cassettes 2 serving as carriers of the wafer 1 can be placed. The cassette stage 13 is transferred by an external transfer device (not shown). Is placed on the cassette stage 13 in a vertical posture (the wafer 1 accommodated in the cassette 2 is vertical), the cassette 2 is turned to a horizontal posture by rotating 90 degrees. A cassette elevator 14 is installed on the rear side of the cassette stage 13, and the cassette elevator 14 is configured to raise and lower the cassette transfer device 15. A cassette shelf 17 that is traversed by a slide stage 16 is installed behind the cassette elevator 14, and a buffer cassette shelf 18 is installed above the cassette shelf 17. A clean unit 19 that circulates clean air inside the housing 11 is installed on the rear side of the buffer cassette shelf 18. In addition, a wafer transfer device 20 that can transfer a plurality of wafers 1 at a time or to a single wafer is provided on the rear side of the cassette shelf 17 so as to be rotatable and liftable. .
[0013]
A pressure-resistant casing 22 having an exhaust pipe 21 that exhausts to a pressure lower than atmospheric pressure is installed below the rear end of the casing 11. The pressure-resistant casing 22 forms a standby chamber 23 in which a boat waits. Yes. A wafer loading / unloading port 24 is opened on the front wall of the pressure-resistant housing 22, and the wafer loading / unloading port 24 is opened and closed by a load lock door 25. As shown in FIG. 2, a boat carry-in / out opening 26 is formed in the ceiling wall of the pressure-resistant housing 22, and a seal ring 27 is provided on the lower surface of the ceiling wall of the pressure-resistant housing 22. Is laid to surround. The boat loading / unloading port 26 is opened and closed by a shutter 28. A heater unit 29 is installed vertically on the pressure-resistant housing 22, and a process tube 30 is arranged inside the heater unit 29. The process tube 30 is formed in a cylindrical shape with the upper end closed and the lower end opened, and is disposed concentrically with the heater unit 29. The process chamber 31 is constituted by the cylindrical hollow portion of the process tube 30. Connected to the lower end of the process tube 30 are a gas introduction pipe 32 for introducing a raw material gas, a purge gas or the like into the processing chamber 31 of the process tube 30, and an exhaust pipe 33 for exhausting the processing chamber 31.
[0014]
An insertion hole 34 is formed in the ceiling wall of the pressure-resistant housing 22 in the vicinity of the boat loading / unloading exit 26, and a fixed base 35 is installed on the insertion hole 34 in the ceiling wall of the pressure-resistant housing 22. The fixed base 35 is formed in a cylindrical body whose upper end is closed, and a bellows storage chamber 36 is formed to be continuous with the insertion hole 34 by a hollow portion of the fixed base 35. A boat elevator 40 for raising and lowering the boat is installed on the fixed base 35. The boat elevator 40 is engaged with a guide rail 43 and a feed screw shaft 44 laid vertically by an upper mounting plate 41 and a lower mounting plate 42, respectively, and is screwed into the feed screw shaft 44 so as to be relatively movable in the vertical direction. And a nut 45 for converting the rotational motion of the screw shaft 44 into linear motion. The nut 45 is formed in a disk shape and is fixed by a guide block 46 installed on the fixed base 35, and a guide rail 43 is slidably inserted in the guide block 46 in the vertical direction. In order to improve the operation and backlash, a ball screw mechanism is used at the threaded portion between the feed screw shaft 44 and the nut 45. The upper end portion of the feed screw shaft 44 passes through the upper mounting plate 41 and is connected so as to be driven forward and reverse by a motor 47 installed on the upper mounting plate 41. That is, the upper mounting plate 41 and the motor 47 constitute a motor portion installed at the outer end of the standby chamber 23 of the guide rail 43 and the feed screw shaft 44.
[0015]
A bellows 48 that hermetically seals the guide rail 43 and the feed screw shaft 44 is interposed between the ceiling surface of the bellows storage chamber 36 and the upper surface of the lower mounting plate 42. An arm 49 is provided horizontally on the lower surface of the lower mounting plate 42, and a seal cap 50 is provided on the tip of the arm 49 via a boat rotation drive motor 51. The seal cap 50 is configured to seal the boat loading / unloading port 26 of the pressure-resistant casing 22 that becomes the furnace port of the processing chamber 31 by crushing the seal ring 27. A boat 53 is installed on the upper end of the rotation shaft 52 of the boat rotation driving motor 51 so as to stand vertically. The boat 53 has a plurality of wafers 1 (for example, 25 sheets, 50 sheets, 75 sheets, 100 sheets, 150 sheets, etc.) in a state where the wafers 1 are horizontally supported with their centers aligned, with respect to the processing chamber 31 of the process tube 30. The boat elevator 40 is configured to carry in and out as the arm 49 moves up and down.
[0016]
Hereinafter, a heat treatment process using the batch heat treatment apparatus according to the above configuration will be described.
[0017]
A cassette 2 storing a plurality of wafers 1 is supplied to a cassette stage 13 of a cassette transfer unit 12 by an external transfer device. The supplied cassette 2 assumes a horizontal posture as the cassette stage 13 rotates 90 degrees. The cassette 2 in the horizontal posture is transferred to the cassette shelf 17 or the buffer cassette shelf 18 by the cassette transfer device 15 and transferred.
[0018]
The wafer 1 stored in the cassette 2 to be formed is loaded into the standby chamber 23 through the wafer loading / unloading port 24 of the pressure-resistant housing 22 by the wafer transfer device 20 and loaded (charged) into the boat 53. At this time, as shown in FIG. 1, the boat loading / unloading port 26 is closed by the shutter 28, thereby preventing the high temperature atmosphere of the processing chamber 31 from flowing into the standby chamber 23. For this reason, the wafer 1 being loaded and the loaded wafer 1 are not exposed to a high temperature atmosphere, and the occurrence of adverse effects such as natural oxidation due to the wafer 1 being exposed to a high temperature atmosphere is prevented.
[0019]
When a predetermined number of wafers 1 are loaded into the boat 53, the wafer loading / unloading port 24 is closed by the load lock door 25, and the boat loading / unloading port 26 is opened by the shutter 28.
[0020]
Subsequently, when the feed screw shaft 44 is rotated in the forward direction by the motor 47 of the boat elevator 40, the nut 45 with which the feed screw shaft 44 is screwed is fixed to the fixed base 35 via the guide block 46. The motor 47 itself moves vertically together with the feed screw shaft 44 and the guide rail 43 with the guide block 46 as a guide. As the feed screw shaft 44 and the guide rail 43 are raised, the arm 49 connected to the feed screw shaft 44 and the guide rail 43 is raised, so that the boat 53 supported by the arm 49 via the seal cap 50 is It is loaded into the processing chamber 31 of the process tube 30 from the boat loading / unloading port 26 (boat loading). As shown in FIG. 3, when the boat 53 reaches the upper limit, the periphery of the upper surface of the seal cap 50 causes the boat loading / unloading port 26 to be crushed by the seal ring 27 and closed in a sealed state. The 30 treatment chambers 31 are closed in an airtight manner. When the feed screw shaft 44 and the guide rail 43 are raised when the boat 53 is carried into the processing chamber 31, the bellows 48 is shortened upward and is housed in the bellows housing chamber 36.
[0021]
Thereafter, the processing chamber 31 of the process tube 30 is closed in an airtight manner, is exhausted by the exhaust pipe 33 so as to have a predetermined pressure, heated to a predetermined temperature by the heater unit 29, and a predetermined source gas is introduced into the gas. A predetermined flow rate is supplied by the pipe 32. Thereby, the wafer 1 is subjected to heat treatment corresponding to preset processing conditions. At this time, since the boat 53 is rotated by the boat rotation drive motor 51, the source gas is uniformly brought into contact with the surface of the wafer 1, so that the wafer 1 is uniformly heat-treated.
[0022]
When the preset processing time has elapsed, the feed screw shaft 44 is rotated in the reverse direction by the motor 47 of the boat elevator 40. When the feed screw shaft 44 is rotated in the opposite direction, the nut 45 into which the feed screw shaft 44 is screwed is fixed to the fixing base 35 via the guide block 46, so that the motor 47 itself is connected to the feed screw shaft 44. The guide block 46 is guided along with the guide rail 43 to descend vertically. As the feed screw shaft 44 and the guide rail 43 are lowered, the arm 49 connected to the feed screw shaft 44 and the guide rail 43 is lowered. As shown in FIG. The boat 53 supported via the process tube is unloaded from the processing chamber 31 of the process tube 30 (unboat loading). When carrying out the boat 53 from the processing chamber 31, if the feed screw shaft 44 and the guide rail 43 are lowered, the bellows 48 extends downward and is pulled out from the bellows storage chamber 36.
[0023]
When the boat 53 is unloaded from the processing chamber 31 to the standby chamber 23, the boat loading / unloading port 26 is closed by the shutter 28, and the wafer loading / unloading port 24 of the standby chamber 23 is opened by the load lock door 25. Thereafter, the processed wafers 1 in the boat 53 are removed (discharged) by the wafer transfer device 20 and stored in the empty cassette 2. The cassette 2 storing the predetermined number of processed wafers 1 is transferred to the cassette transfer unit 12 by the cassette transfer device 15.
[0024]
Thereafter, by repeating the above-described operation, for example, the wafer 1 is batch-processed by the batch heat treatment apparatus 10 by 25 sheets, 50 sheets, 75 sheets, 100 sheets, 150 sheets, for example.
[0025]
According to the embodiment, the following effects can be obtained.
[0026]
1) By fixing the nut 45 of the feed screw shaft device constituting the boat elevator 40 and moving the feed screw shaft 44 up and down, the feed screw shaft 44 ′ is fixed as shown in FIG. Compared to the case where the nut 45 'is lifted and lowered, the lift shaft 60 can be omitted, so the number of parts can be reduced.
[0027]
2) As shown in FIG. 3, the distance L1 in the horizontal direction of the load center when the seal ring 27 is crushed by the seal cap 50 to hermetically seal the boat loading / unloading port 26 is shown in FIG. This can be shortened compared to the horizontal distance L2 in the example. Further, the vertical distance h1 between the support point of the guide rail 43 and the load center can also be shortened compared to the vertical distance h2 in the example shown in FIG. Furthermore, by supporting the nut 45 and the guide block 46 on the fixed base 35 and omitting the elevating shaft 60, the amount of bending of the arm 49 can be reduced as compared with the example shown in FIG. Therefore, by setting the mechanical strength or rigidity of each component of the boat elevator 40 to be small, the initial cost and running cost of the boat elevator 40 and thus the batch heat treatment apparatus 10 can be significantly reduced.
[0028]
3) Since the total height of the boat elevator 40 during standby in the standby chamber 23 of the boat 53 can be set lower than the total height of the heater unit 29 as shown in FIG. The efficiency of installation work and adjustment work can be improved. In the case of the example shown in FIG. 4, since the total height of the boat elevator 40 'exceeds 3000 mm, the boat elevator 40' is disassembled and shortened to 2800 mm or less, which is the maximum allowable height of air mail. After being transported, installed and reassembled, operations such as adjusting the operation of the boat elevator 40 'are unavoidable.
[0029]
4) By covering the guide rail 43 and the feed screw shaft 44 of the boat elevator 40 with the bellows 48, organic substances such as grease applied to the guide rail 43 and the feed screw shaft 44 are prevented from scattering into the standby chamber 23. Therefore, contamination of the wafer 1 with an organic substance can be prevented in advance.
[0030]
5) By immediately unloading the boat 53 holding the processed wafer 1 from the processing chamber 31, the waiting time for cooling the processed wafer 1 can be omitted. Can be increased.
[0031]
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.
[0032]
The batch-type heat treatment apparatus is not limited to use for film formation, but can also be used for heat treatment such as oxide film formation, diffusion, and annealing.
[0033]
Although the case of the batch type heat treatment apparatus has been described in the above embodiment, the present invention is not limited to this, and can be applied to all substrate processing apparatuses including a boat elevator.
[0034]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent contamination by a boat elevator while avoiding an increase in size.
[Brief description of the drawings]
FIG. 1 is a partially omitted perspective view showing an entire batch heat treatment apparatus according to an embodiment of the present invention.
FIG. 2 is a side sectional view showing the main part.
FIG. 3 is a side cross-sectional view showing when the boat is loaded.
FIG. 4 is a partially cut side view showing the main part of a comparative example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Wafer (substrate), 2 ... Cassette, 10 ... Batch type heat processing apparatus (substrate processing apparatus), 11 ... Housing | casing, 12 ... Cassette transfer unit, 13 ... Cassette stage, 14 ... Cassette elevator, 15 ... Cassette transfer apparatus , 16 ... Slide stage, 17 ... Cassette shelf, 18 ... Buffer cassette shelf, 19 ... Clean unit, 20 ... Wafer transfer device, 21 ... Exhaust pipe, 22 ... Pressure-resistant housing, 23 ... Standby chamber, 24 ... Loading wafer Outlet, 25 ... Load lock door, 26 ... Boat loading / unloading exit, 27 ... Seal ring, 28 ... Shutter, 29 ... Heater unit, 30 ... Process tube, 31 ... Processing chamber, 32 ... Gas introduction pipe, 33 ... Exhaust pipe, 34 ... Insertion hole, 35 ... Fixing base, 36 ... Bellows storage chamber, 40 ... Boat elevator, 41 ... Upper mounting plate, 42 ... Lower mounting plate, 43 ... Gas Drake, 44 ... feed screw shaft, 45 ... nut, 46 ... guide block, 47 ... motor, 48 ... bellows, 49 ... arm, 50 ... seal cap, 51 ... boat rotation drive motor, 52 ... rotary shaft, 53 ... boat 60, elevating shut, L1, L2 ... horizontal distance, h1, h2 vertical distance.

Claims (1)

A processing chamber that performs processing in a state where a plurality of substrates are held in a boat, a standby chamber connected to the processing chamber, and a boat that moves the boat into and out of the processing chamber and the standby chamber In a substrate processing apparatus provided with an elevator,
The boat elevator includes a guide rail and a feed screw shaft that are inserted into an insertion hole formed in the standby chamber so as to extend in and out of the standby chamber, and an outer side of the standby chamber of the guide rail and the feed screw shaft. A motor part installed at one end of the motor, a guide block in which the guide rail is slidably inserted and fixed in the standby chamber, and the feed screw shaft fixed to the guide block and rotated by the motor is screwed. A substrate processing apparatus comprising: a combined nut;

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