JP2013235899A - Device for thermally treating silicon disc for plasma processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce in-plane variation of a specific resistance of a silicon disc by proper thermal treatment.SOLUTION: A thermal treatment device of a silicon disc has: a frame-like disc holding tool supporting plural silicon discs under a leaning state that they are isolated from each other; a heating chamber for heating the silicon discs; a cooling chamber provided adjacent to the heating chamber and cooling the silicon discs; and transfer means for transferring the disc holding tool between the heating chamber and the cooling chamber. The cooling chamber comprises: swing means for rotating and swinging the disc holding tool around a vertical axial line; and blow means for blowing cooling wind to the silicon discs held by the disc holding tool swung by the swing means. The swing means and the blow means are arranged so that the silicon discs are swung with a center while a plane direction of the silicon discs is almost parallel to a blowing direction of the cooling wind by the blowing means.

Description

  The present invention relates to a heat treatment apparatus for a silicon disk for a plasma processing apparatus.

  In a plasma processing apparatus such as a plasma CVD apparatus, a plasma etching apparatus, or a plasma CVD apparatus used in a semiconductor device manufacturing process, for example, an upper electrode and a lower electrode connected to a high-frequency power source are disposed in a vertical direction in a chamber. In a state where the substrate to be processed is disposed on the lower electrode, plasma is generated by applying a high-frequency voltage while flowing an etching gas from the air hole formed in the upper electrode toward the substrate to be processed. Processes such as film formation and etching are performed on the substrate to be processed.

  Conventionally, single crystal silicon electrode plates, polycrystalline silicon electrode plates, columnar crystal silicon electrode plates, and the like have been used as electrode plates for this plasma processing apparatus, but in recent years, single crystal silicon ingots manufactured by the CZ method have been used. A single crystal silicon electrode plate produced by cutting into a disk shape and polishing the surface is mainly used.

  When plasma etching is performed using such a single crystal silicon electrode plate, for example, it has been confirmed that the variation in the etching rate on the wafer surface becomes smaller as the in-plane variation in the specific resistance value of the silicon electrode plate is smaller. For this reason, a silicon electrode plate with a small variation in specific resistance value is required (see Patent Document 1).

  In Patent Document 1, since the specific resistivity of the single crystal silicon ingot has a large difference between the outer peripheral portion and the central portion, it is possible to manufacture an electrode plate with small in-plane variation in specific resistance value by removing the outer peripheral portion. Have been described.

  Patent Document 2 describes a heat treatment apparatus for a semiconductor wafer that makes the resistivity distribution in the surface of the semiconductor wafer uniform by performing appropriate temperature control.

  Patent Document 3 describes a heat treatment apparatus that improves the non-uniformity of heating of a silicon wafer.

  In Patent Document 4, heat treatment is performed while measuring the resistance of the substrate surface, and the resistance value of the polycrystalline silicon film is stopped by stopping the movement of the heat treatment apparatus when the measured resistance value reaches a preset resistance value. Describes a technique for setting the resistance value to a preset resistance value.

JP 2007-158007 A JP-A-6-104269 JP 2003-209063 A JP 2007-59497 A

  Conventionally, as disclosed in Patent Documents 2 to 4, it has been studied to enable uniform heating and appropriate temperature control in a heat treatment apparatus for a silicon wafer. Further, for silicon electrode plates, there is a demand for the realization of a heat treatment apparatus that can reduce variations in specific resistance values by uniform cooling. However, since the silicon electrode plate is thicker and heavier than a silicon wafer, it is difficult to handle and uniform cooling is difficult. In particular, it was very difficult to heat treat a plurality of electrode plates simultaneously.

  The present invention has been made in view of such circumstances, and a heat treatment apparatus capable of performing appropriate heat treatment on a plurality of silicon disks and reducing in-plane variation in specific resistance of silicon disks. The purpose is to provide.

  The present invention relates to a silicon disk heat treatment apparatus for a plasma processing apparatus, a frame-shaped disk holder made of quartz that supports a plurality of silicon disks in a standing state spaced apart from each other, and the disk holder A heating chamber in which the silicon disk held in a state is heated, and a cooling chamber provided adjacent to the heating chamber and in which the silicon disk held in the disk holder is cooled. A transfer means for transferring the disc holder between the heating chamber and the cooling chamber, and the disc holder holding the silicon disc is disposed around the vertical axis in the cooling chamber. Oscillating means for rotating and oscillating, and blasting means for blowing cooling air to the silicon disk held by the disk holder oscillated by the oscillating means are provided. Before the cooling air blowing direction As the planar direction of the silicon discs around the substantially parallel with the silicon disc is swung, the oscillating means and the blower means is arranged.

  According to this heat treatment apparatus, the cooling air is supplied to the entire surface of the silicon disk by supplying the cooling air while swinging the silicon disk held in a small contact area by the frame-shaped disk holder. Therefore, the silicon disk is efficiently cooled. Therefore, the heated silicon disk can be quickly cooled to the target temperature, and the in-plane variation of the specific resistance of the silicon disk used for the electrode plate or the like can be reduced.

  In this heat treatment apparatus, the disk holder includes two mounting recesses on which outer peripheral edges of one silicon disk are mounted, and one of the silicon disks mounted on the mounting recesses. It is preferable to have a plurality of disk holding portions each including a plate surface support portion that supports the plate surface by placing the plate surface on the surface. In this case, the cooling air is supplied while being swung in a state where the silicon disk is supported at two positions on the outer peripheral edge and at three positions on one plate surface in the disk holding portion. That is, since the part which contacts a silicon disc can be minimized, the whole silicon disc can be cooled uniformly.

  In this heat treatment apparatus, it is preferable that glass fiber is disposed at a position where the disk holder comes into contact with the silicon disk. In this case, the silicon disk can be prevented from being broken due to cracking or chipping.

  In this heat treatment apparatus, it is preferable that a preliminary chamber for waiting the cooled silicon disc is provided adjacent to the cooling chamber. In this case, since the silicon disk before heating in the next step can be put into the heat treatment apparatus before the operation of carrying out the cooled silicon disk from the heat treatment apparatus is completed, the working time can be shortened.

  According to the silicon disk heat treatment apparatus for a plasma processing apparatus of the present invention, it is possible to efficiently perform appropriate heat treatment and reduce the in-plane variation of the resistivity of the silicon disk.

It is a top view which shows the outline | summary of the heat processing apparatus of the silicon disc for plasma processing apparatuses of this invention. It is a perspective view which shows the disc holder which comprises the heat processing apparatus of FIG. It is a side view which shows typically the disc holder of FIG. 2, and a silicon disc.

  Embodiments of a heat treatment apparatus for a silicon disk for a plasma processing apparatus according to the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the heat treatment apparatus 10 of the present embodiment is made of quartz, and includes a disk holding portion 21 (see FIG. 2) that can hold the silicon disk P in a state in which the surface of the silicon disk P extends along a substantially vertical direction. By providing a plurality, the frame-shaped disk holder 20 that supports the plurality of silicon disks P in a standing state spaced apart from each other, and heating that heats the silicon disk P held by the disk holder 20 The cooling chamber 40 provided adjacent to the chamber 30 and the heating chamber 30 and cooled by the silicon disc P held by the disc holder 20 is circular between the heating chamber 30 and the cooling chamber 40. It has the transfer means 50 which transfers the plate holder 20, and the cart 70 which conveys the disk holder 20 outside the heating chamber 30 and the cooling chamber 40.

  The silicon disk P is a disk-shaped member made of silicon having a thickness of 11.5 mm and a diameter of 200 to 600 mm, for example, and can be stabilized in in-plane variation in specific resistance value by performing a predetermined heat treatment. It is used for a disk-shaped electrode plate for a plasma processing apparatus. Further, the silicon disk P heat-treated by the heat treatment apparatus 10 is further processed to be used as a ring material for a plasma processing apparatus. In the heat treatment apparatus 10, the silicon disk P is first carried into the cooling chamber 40, transferred from the cooling chamber 40 into the heating chamber 30 by the transfer means 50 and heated to a predetermined temperature, and then from the heating chamber 30 to the cooling chamber. 40, cooled to a target temperature at a predetermined cooling rate, and taken out from the heat treatment apparatus 10.

  As shown in FIGS. 1 and 3, the disc holder 20 that holds the silicon disc P is conveyed in a state of being placed on a tray 24 formed of stainless steel. Outside the heating chamber 30 and the cooling chamber 40, the tray 24 on which the disc holder 20 is placed is placed and transported on the upper surface of the carriage 70 set at substantially the same height as the inner lower surface of the cooling chamber 40. . Thereby, the movement of the disc holder 20 between the cart 70 and the cooling chamber 40 is facilitated.

  The cooling chamber 40 is provided with doors D <b> 1 and D <b> 2 that communicate with the outside of the heat treatment apparatus 10 in order to take in and out the disc holder 20 that holds the silicon disc P. The disc holder 20 is carried into the cooling chamber 40 through the door D1, while being carried out of the cooling chamber 40 through the door D2. The heating chamber 30 and the cooling chamber 40 are disposed adjacent to each other. By opening the door D3 provided between the heating chamber 30 and the cooling chamber 40, the heating chamber 30 and the cooling chamber 40 are disposed between the heating chamber 30 and the cooling chamber 40. The silicon disk P can be moved. That is, in the configuration of the heat treatment apparatus 10 of the present embodiment, since the heating chamber 30 is connected to the cooling chamber 40 through the door D3, the silicon disk P before and after heating is taken in and out of the heating chamber 30. It passes through the cooling chamber 40.

  The cooling chamber 40 includes a swinging means 41 for rotating and swinging the disk holder 20 holding the silicon disk P around a vertical axis, and a disk holder 20 swung by the swinging means 41. Blowing means 60 for blowing cooling air to the held silicon disk P is provided. A duct (not shown) is provided in the upper portion of the cooling chamber 40, and indoor air heated by the heated silicon disc P can be discharged to the outside.

  The swinging means 41 includes a turntable 42 that can rotate around a vertical axis, and can be rotated forward and reverse in a range of, for example, 90 ° by a driving device (not shown). Further, the turntable 42 is provided with a stopper (not shown) that can prevent the mounted disk holder 20 from moving.

  The blower 60 is a device that blows air that has been cooled to a desired temperature by a water cooling device (not shown), for example, toward the silicon disk P disposed on the turntable 42 of the swinging means 41. The blowing direction of the cooling air by the blowing means 60 is substantially horizontal, and the silicon disk P on the turntable 42 is swung around a state where the surface direction is substantially parallel to the blowing direction. Placed in.

  Further, the cooling chamber 40 is provided with a spare chamber 43 that waits for the cooled silicon disc P in a portion that does not overlap the moving route of the disc holder 20 between the heating chamber 30 and the cooling chamber 40. Yes. The spare chamber 43 is provided with a conveyance roller 44 for moving the disk holder 20 (tray 24), and the disk holder 20 can be conveyed from the turntable 42 to the door D2.

  In the heat treatment process of the silicon disk P, the silicon disk P before heating is carried into the heating chamber 30 from the door D1 through the cooling chamber 40 while the preliminary cooling chamber 43 is waiting for the cooled silicon disk P. can do. And while the next heating process is performed in the heating chamber 30, the silicon disc P kept in the standby chamber 43 can be unloaded from the door D2 and transported using the carriage 70. . Thus, by using the spare chamber 43, the silicon disc P before cooling can be quickly carried into the heating chamber 30.

  The transfer means 50 for transferring the silicon disk P between the heating chamber 30 and the cooling chamber 40 advances and retreats through the doors D1 and D2 through the heating chamber 30 and the cooling chamber 40 as shown in FIG. A transfer rod 51 is provided. Along with the tray 24 and the disc holder 20, the hook portion 51 a formed at the tip of the transfer rod 51 is engaged with the tray 24 on which the disc holder 20 is placed and the transfer rod 51 is advanced and retracted. The silicon disk P can be moved between the cooling chamber 40 and the heating chamber 30.

  The heating chamber 30 is provided with, for example, a SiC heater (not shown), and can heat the silicon disk P disposed in the chamber to a desired temperature.

  As shown in FIG. 2, the disk holder 20 is formed by combining a plurality of quartz round bars, and a plurality of disk holders 21 that can hold a single silicon disk P (in this embodiment, 5 Set) is provided.

  The disk holder 20 includes four sets of bases 20A composed of three quartz rods assembled in a U-shape with an upper opening, and each base 20A orthogonal to these bases 20A arranged at equal intervals. A pair of girders 20B joined so as to connect each other, a column 20C joined to each base 20A so as to extend upward from each base 20A, and each pillar 20C A pair of beam portions 20D each provided with five mounting recesses 22 on which the outer peripheral edge of the silicon disk P is mounted, and three quartz circles that are assembled in a trapezoidal shape that is open at the bottom and narrow at the top. It is formed by combining six sets of flanges 20E that are made of rods and spanned between the pair of girders 20B, and holds one silicon disk P between each of the flanges 20E. Can do.

  Each disk holding part 21 has two mounting recesses 22 on which the outer peripheral edge of one silicon disk P is mounted, and one of the silicon disks P mounted on these mounting recesses 22. And a plate surface support portion 23 that supports the surface by placing it on the surface. Each mounting recess 22 is formed at one location on each pair of beam portions 20D in each disk holding portion 21. Each plate surface support portion 23 is carried by a flange portion 20E spanned between a pair of beam portions 20B. In each disk holding part 21 of the disk holding part 20, a glass fiber tape is wound around at least a part where the silicon disk P is in contact for the purpose of protecting the silicon disk P (not shown).

  As shown in FIGS. 2 and 3, in each disk holding portion 21, the silicon disk P is held so as not to slide in the horizontal direction by placing the outer peripheral edge on the mounting recess 22, and the plate surface It is stable without falling by being put on the support portion 23. That is, since the silicon disc P is only supported at two locations on the outer peripheral edge and three locations on one plate surface, the contact area by the disc holder 21 is small. For this reason, the cooling air from the ventilation means 60 is easy to be supplied to the whole surface of the silicon disk P, and efficient cooling is possible.

  An operation operation using the heat treatment apparatus 10 configured as described above will be described. First, the door D1 of the cooling chamber 40 is opened, and the disk holder 20 holding the silicon disk P is put into the cooling chamber 40 from the carriage 70, and then the door D1 is closed.

  Next, the door D3 is opened, the transfer rod 51 is advanced, and the hook portion 51a is engaged with the tray 24 of the disk holder 20 in the cooling chamber 40. Next, the transfer rod 51 is retracted, the tray 24 and the disc holder 20 are drawn into the heating chamber 30, and the door D3 is closed.

  When the heating process of the silicon disc P in the heating chamber 30 is completed, the door D3 is opened and the transfer rod 51 is advanced to transfer the disc holder 20 holding the heated silicon disc P to the cooling chamber 40. Place on the turntable 42. Moreover, the ventilation by the ventilation means 60 is started.

  When the silicon disk P is cooled by blowing air while swinging the turntable 42 and the temperature of the silicon disk P (or the disk holder 20) is lowered to a predetermined temperature (for example, 300 ° C.), the turntable 42 is turned on. Is rotated by 90 °, and the disk holder 20 is transferred to the spare chamber 43 and waited.

  When the cooled disk holder 20 is retracted from the turntable 42, the blowing by the blowing means 60 is stopped and the door D1 is opened, and the next silicon disk P and the disk holder 20 are moved from the cart 70 to the tray 24. At the same time, it is introduced into the heating chamber 30 through the cooling chamber 40 and the next heating step is started. While this heating process is being performed, the door D2 is opened, the disk holder 20 in the preliminary chamber 43 is taken out from the cooling chamber 40, and is transferred onto the carriage 70.

  As described above, according to the heat treatment apparatus 10, the disk holder 20 is configured so that the silicon disk P is supported at two locations on the outer peripheral edge and at three locations on one plate surface. It is possible to cool the silicon disk P uniformly by supplying the cooling air to the entire surface of the silicon disk P while keeping the portion in contact with the silicon disk P small. Further, since the cooling air is supplied while the silicon disk P is swung, the cooling air can be distributed more efficiently and uniformly over the entire surface of the silicon disk P. Therefore, the heated silicon disk P can be quickly and uniformly cooled to the target temperature, and the in-plane variation of the specific resistance of the silicon disk P can be reduced.

  Further, in this heat treatment apparatus 10, a spare chamber 43 for waiting the cooled silicon disk P is provided adjacent to the cooling chamber 40, so that the cooled silicon disk P is treated as the heat treatment apparatus 10 (cooling chamber). 40) The silicon disk P before heating in the next step can be put into the heat treatment apparatus 10 before the work to be carried out from step 40) is completed. Therefore, the working time can be shortened.

  In addition, this invention is not limited to the thing of the structure of the said embodiment, In a detailed structure, it is possible to add a various change in the range which does not deviate from the meaning of this invention. For example, in the above embodiment, there is one door through which an electrode plate (silicon disk) is taken in and out of the heating chamber, and the heating chamber and the cooling chamber are connected through this door. By providing a spare chamber at a position that does not interfere with the loading of the electrode plate, it is possible to shorten the work time required for loading and unloading the electrode plate. However, in the case where a separate door for loading the electrode plate before heating and a door for taking out the electrode plate after heating are separately provided in the heating chamber, the position of the spare chamber may be adjacent to the cooling chamber, or the spare chamber The structure which does not provide a chamber may be sufficient.

DESCRIPTION OF SYMBOLS 10 Heat processing apparatus 20 Disk holder 20A Base 20B Girder part 20C Column part 20D Beam part 20E Girder part 21 Disk holder part 22 Mounting recessed part 23 Plate surface support part 24 Tray 30 Heating room 40 Cooling room 41 Oscillating means 42 Turn Table 43 Preliminary chamber 44 Transport roller 50 Transfer means 51 Transfer rod 51a Hook part 60 Blower means 70 Dolly D1, D2, D3 Door P Silicon disc

Claims (4)

A heat treatment apparatus for a silicon disk for a plasma processing apparatus,
A frame-shaped disk holder made of quartz that supports a plurality of silicon disks in a standing state spaced apart from each other;
A heating chamber in which the silicon disk held by the disk holder is heated;
A cooling chamber which is provided adjacent to the heating chamber and in which the silicon disc in a state of being held by the disc holder is cooled;
Transfer means for transferring the disk holder between the heating chamber and the cooling chamber;
The cooling chamber is held by a swinging means for rotating and swinging the disk holder holding the silicon disk about a vertical axis, and the disk holder swinged by the swinging means. An air blowing means for blowing cooling air to the silicon disk;
The oscillating means and the air blowing means are arranged such that the silicon disk is oscillated around a state in which the surface direction of the silicon disk is substantially parallel to the air blowing direction of the cooling air by the air blowing means. A silicon disk heat treatment apparatus for a plasma processing apparatus.   The disk holder has two mounting recesses on which the outer peripheral edge of one silicon disk is mounted, and one plate surface of the silicon disk mounted on these mounting recesses. 2. The silicon disk heat treatment apparatus for a plasma processing apparatus according to claim 1, wherein the apparatus includes a plurality of disk holding portions each including a plate surface support portion that is hung and supported. 3.   3. The heat treatment apparatus for a silicon disk for a plasma processing apparatus according to claim 1, wherein a preliminary chamber for waiting the cooled silicon disk is provided adjacent to the cooling chamber.   4. The heat treatment apparatus for a silicon disk for a plasma processing apparatus according to claim 1, wherein glass fibers are disposed at a position where the disk holder comes into contact with the silicon disk.

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