JP4180424B2 - Substrate processing apparatus, substrate processing method, and IC manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate processing apparatus, and more particularly to a heat insulating structure of a heater unit. For example, in a method of manufacturing a semiconductor integrated circuit device (hereinafter referred to as an IC), a semiconductor wafer (hereinafter referred to as a wafer) in which an IC is fabricated. ) Is effective in performing thermal treatment such as oxidation treatment, diffusion treatment, annealing treatment, carrier activation treatment after ion implantation, reflow treatment for planarization, and film formation treatment.
[0002]
[Prior art]
In an IC manufacturing method, a batch type vertical hot wall type heat treatment apparatus (furnace) is widely used to perform various heat treatments on a wafer. The batch-type vertical hot wall heat treatment system includes a process tube that forms a vertical processing chamber that processes multiple wafers at once, a soaking tube installed outside the process tube, and the outside of the soaking tube And a heater unit for heating the processing chamber and a boat for holding a plurality of wafers and carrying them into the processing chamber, and a heat insulating tank in which a heat insulating material such as ceramic fiber is formed in a cylindrical shape. Some heater units are constructed by laying a heating element on the inner peripheral surface (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-164298
[Problems to be solved by the invention]
However, in the conventional batch type vertical hot wall heat treatment apparatus, since the heat insulating tank of the heater unit is formed of a heat insulating material such as ceramic fiber, there is a problem that a great amount of electric power is wasted. That is, in order to raise the temperature of the wafer group in the processing chamber and stabilize it at a predetermined processing temperature, not only the temperature of the processing chamber but also the heat insulating material having a large heat capacity is heated to a predetermined processing temperature. Need to be maintained. In addition, when the temperature of the processing chamber is lowered at the time of loading / unloading of the boat, it is necessary to lower the temperature of the heat insulating tank. However, since the heat insulating material has a large heat capacity, a large-scale cooling device is required, Electricity is wasted. In other words, in a heat insulating tank formed of a heat insulating material that is difficult to heat and hard to cool, there is a limit to the rate of temperature rise and fall, and the heat insulating material is heated and maintained or cooled rather than heating the wafer. A large amount of power is required to achieve a situation.
[0005]
An object of the present invention is to provide a substrate processing apparatus capable of efficiently raising and lowering the temperature.
[0006]
[Means for Solving the Problems]
A substrate processing apparatus according to the present invention includes a processing chamber for processing a substrate and a heater unit for heating the processing chamber.
The heater unit includes a heating element laid so as to surround the outside of the processing chamber, a first reflector laid so as to surround the heating element, and a space outside the first reflector. A second reflector laid on, an exhaust pipe for exhausting the space, and a supply pipe for supplying gas to the space,
A reflective coating film made of a multilayer coating film of silicon oxide or silicon nitride is deposited on the surfaces of the first reflector and the second reflector.
[0007]
According to the above-described means, by setting the heat capacities of the first reflector and the second reflector small, it is possible to suppress the thermal energy consumed by the first reflector and the second reflector, Since the temperature rate can be set large, the temperature of the processing chamber can be raised and lowered efficiently.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0009]
In the present embodiment, as shown in FIG. 1, the substrate processing apparatus according to the present invention is configured as a batch type vertical hot wall type oxidation / diffusion apparatus (hereinafter referred to as an oxidation / diffusion apparatus).
[0010]
Oxidation and diffusion apparatus shown in FIG. 1 10 is provided with a vertical process tubes 11 center line is fixedly supported is disposed vertically so as to be perpendicular, the process tube 11 is quartz (SiO ₂ ) Is used to form a cylindrical shape with the upper end closed and the lower end opened. A processing chamber 12 for collectively processing a plurality of wafers 1 is formed by a cylindrical hollow portion, and a furnace port 13 for taking in and out the wafers 1 is formed by a lower end opening of the process tube 11. A soaking tube 14 is concentrically placed outside the process tube 11, and the soaking tube 14 is made of silicon carbide and is formed in a cylindrical shape having a larger diameter than the process tube 11 with the upper end closed and the lower end opened. Has been. A vent hole 14 a is formed in the upper end blocking wall of the soaking tube 14. An air passage 15 is formed in a donut shape between the process tube 11 and the soaking tube 14, and clean air as a refrigerant flows through the air passage 15. Clean air is discharged from the vent hole 14a. The process tube 11 and the soaking tube 14 are vertically supported by a casing 16 of the oxidation / diffusion apparatus. One end of an exhaust pipe 17 is connected to the lower end portion of the side wall of the process tube 11, and the other end of the exhaust pipe 17 is connected to an exhaust device (not shown) to exhaust the processing chamber 12 to a predetermined pressure. It is configured as follows. A gas introduction pipe 18 for introducing a processing gas into the processing chamber 12 is inserted at a position different from the exhaust pipe 17 at the lower end of the side wall of the process tube 11.
[0011]
A disc-shaped seal cap 21 is installed below the process tube 11 so as to be lifted and lowered by a boat elevator (not shown) on an extension of the center line of the process tube 11. On the seal cap 21, a heat insulating cap 22 is installed vertically to insulate the vicinity of the furnace port 13 of the process tube 11. The heat insulating cap 22 is configured by holding a plurality of heat insulating plates 24 in a state of being aligned horizontally and centered by a plurality of holding members 23. A sub-heater unit 25 formed in a disk shape is coaxially and horizontally installed on the heat insulation cap 22, and a boat 26 is vertically installed on the sub-heater unit 25. The boat 26 is configured so that a plurality of wafers 1 are aligned and held in a state where their centers are aligned with each other by a plurality of holding members 27. A temperature sensor 28 is inserted into the seal cap 21 in the vertical direction.
[0012]
A heater unit 30 is installed outside the soaking tube 14 so as to entirely cover the soaking tube 14, and the heater unit 30 is vertically supported by the housing 16. The heater unit 30 includes a case 31 formed in a cylindrical shape with a thin steel plate or the like, and a heat insulating material 32 such as a ceramic fiber is thinly lined on the inner peripheral surface of the case 31. Inside the heat insulating material 32, a heat insulating tank 33 having a so-called thermos structure is installed concentrically. The heat insulating tank 33 has a first reflector 34 formed in a cylindrical shape having a larger diameter than the outer diameter of the soaking tube 14, and a second reflector 35 formed in a cylindrical shape having a larger diameter than the first reflector 34. The doughnut-shaped space 36 is formed by arranging the first reflector 34 and the second reflector 35 concentrically. The space 36 is configured to be airtight by being closed at both upper and lower ends of the first reflector 34 and the second reflector 35, and a supply pipe 37 and a discharge for circulating a refrigerant through the upper and lower ends of the space 36. Tubes 38 are connected to each other. A heater 39 made of molybdenum silicide (MoSi ₂ ) is laid concentrically inside the first reflector 34 so as to surround the soaking tube 14, and the heater 39 is divided into a plurality of heater portions. . Electric wires 40 for supplying electric power are respectively connected to these heater units, and are configured to be sequenced independently and in cooperation with each other by a temperature controller (not shown). A cooling air passage 42 for circulating the cooling air 41 is formed between the heat insulating tank 33 and the soaking tube 14 so as to entirely surround the soaking tube 14. An air supply pipe 43 that supplies the cooling air 41 to the cooling air passage 42 is connected to the lower end of the heat insulating tank 33, and the cooling air 41 supplied to the air supply pipe 43 is diffused over the entire circumference of the cooling air passage 42. It has become. The upper end of the heat insulating tank 33 is covered with a cover 44 formed of a heat insulating material or the like. An exhaust port 45 is opened at the center of the cover 44, and an exhaust path 46 is connected to the exhaust port 45. A sub-heater unit 47 is installed in the exhaust port 45.
[0013]
As shown in FIG. 2, the first reflector 34 and the second reflector 35 include a main body 51 that is formed in a cylindrical shape using a heat-resistant material such as metal, ceramic, and an insulator. The surface 52 of the main body 51 is mirror-finished by electrolytic polishing or the like. A reflective coating film 53 composed of a multilayer coating film of silicon oxide or silicon nitride is deposited on the surface 52 of the main body 51. The reflective coating film 53 reflects the first reflector 34 and the second reflector 35. The rate has been increased.
[0014]
Next, a heat treatment step in the IC manufacturing method according to the embodiment of the present invention using the oxidation / diffusion apparatus according to the above configuration will be described.
[0015]
As shown in FIG. 1, a boat 26 in which a plurality of wafers 1 are aligned and held is placed on a seal cap 21 in a state where the direction in which a group of wafers 1 is arranged is vertical, and is lifted by a boat elevator. Then, it is carried into the processing chamber 12 from the furnace port 13 of the process tube 11 (boat loading), and remains in the processing chamber 12 while being supported by the seal cap 21.
[0016]
Subsequently, the processing chamber 12 is evacuated to a predetermined pressure by the exhaust pipe 17 and heated to a predetermined temperature by the heater 39. At this time, of the heat rays (infrared rays, far-infrared rays, etc.) irradiated from the heater 39, the heat rays directed outward in the radial direction are reflected by the first reflector 34 arranged on the outer side in the radial direction, thereby being radially inward. Head in the direction. Therefore, all the heat rays irradiated from the heater 39 irradiate the soaking tube 14, and the soaking tube 14 is heated to rapidly raise the temperature with a large sheet (speed). On the other hand, since the first reflector 34 reflects all of the irradiated heat rays without absorbing them, the degree of heat waste can be suppressed. The heat rays emitted from the first reflector 34 to the space 36 are reflected by the second reflector 35 and return to the first reflector 34, so that the heat energy of the heater 39 escapes to the outside of the heat insulating tank 33. Can be almost suppressed. In addition, since the heat capacity of the heat insulating tank 33 constituted by the first reflector 34 and the second reflector 35 is extremely small, the heater 39 hardly wastes heat energy for raising the temperature of the heat insulating tank 33 itself. Before the heater 39 is heated, the space 36 of the heat insulating tank 33 is exhausted by the exhaust pipe 38 and depressurized. The degree of vacuum in the space 36 is adjusted by a pressure control valve (not shown) provided in the exhaust pipe 38. Due to the reduced pressure of the space 36, heat transfer due to heat conduction and convection of air in the space 36 is suppressed, so that the heat insulation effect of the heat insulating tank 33 constituted by the first reflector 34 and the second reflector 35 is further increased. It will be further enhanced.
[0017]
When the pressure and temperature of the processing chamber 12 reach predetermined values and stabilize, a desired processing is performed on the wafer 1 by processing steps such as introducing a processing gas into the processing chamber 12 through the gas introduction pipe 18 at a predetermined flow rate. Is done. When a predetermined processing time has elapsed, for example, after the introduction of the processing gas is stopped, a purge gas such as nitrogen gas is introduced into the processing chamber 12 from the gas introduction pipe 18 and the processing chamber 12 is exhausted by the exhaust pipe 17. The
[0018]
At this time, as shown in FIG. 1, the air passage 15 between the process tube 11 and the heat equalizing tube 14, the cooling air passage 42 between the heat equalizing tube 14 and the heat insulating tank 33, and the heat insulating tank 33. The cooling air 41 is supplied and circulated in the space 36. Due to the circulation of the cooling air 41 in the air passage 15, the cooling air passage 42 and the space 36, the entire oxidation / diffusion apparatus 10 is cooled, so that the temperature of the processing chamber 12 rapidly decreases with a large sheet (speed). It will be. In particular, since the heat insulating tank 33 constituted by the first reflector 34 and the second reflector 35 has a very small heat capacity, it can be rapidly cooled. In addition, since the ventilation path 15, the cooling air passage 42, and the space 36 are isolated from the processing chamber 12, the cooling air 41 can be used as a refrigerant. However, in order to further enhance the cooling effect, impurities in the air In order to prevent corrosion under high temperature due to the above, an inert gas such as nitrogen gas may be used as the refrigerant gas. Further, the flow rate of the cooling air 41 can be adjusted by the output of a flow rate control valve or an exhaust device.
[0019]
When the temperature of the processing chamber 12 is lowered to a predetermined temperature, the boat 26 supported by the seal cap 21 is lowered by the boat elevator and unloaded from the furnace port 13 of the processing chamber 12 (boat unloading). Thereafter, by repeating the above operation, a desired process is performed on the wafer 1 by the oxidation / diffusion apparatus 10.
[0020]
According to the embodiment, the following effects can be obtained.
[0021]
1) Since the heat insulating layer of the heater unit is composed of the first reflector and the second reflector having a small heat capacity, the heat energy wasted in the first reflector and the second reflector can be suppressed, so that the treatment The temperature of the chamber can be raised and lowered rapidly, and the amount of heat energy consumed can be reduced.
[0022]
2) By efficiently raising and lowering the temperature of the processing chamber while reducing the consumption of heat energy, the total processing time of the oxidation / diffusion system can be shortened to improve the performance, and the power consumption cost can be reduced. Therefore, it is possible to reduce the running cost of the oxidation / diffusion apparatus and the manufacturing cost of the IC manufacturing method.
[0023]
3) During the temperature raising step of the processing chamber, the space formed by the first reflector and the second reflector of the heat insulation tank is depressurized to suppress heat conduction by air heat conduction or convection in the space. Since it can do, the heat insulation effect of the heat insulation tank comprised by the 1st reflector and the 2nd reflector can be improved further.
[0024]
4) During the temperature lowering step of the processing chamber, the cooling air can be rapidly cooled by circulating cooling air through the space of the heat insulating bath, so that the cooling time of the processing chamber can be further shortened.
[0025]
5) By using air as the refrigerant, the running cost of the oxidation / diffusion device can be reduced compared to the case where an inert gas such as nitrogen gas is used.
[0026]
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.
[0027]
For example, a reflector may be installed right above the sub heater unit 47 interposed in the exhaust port 45 so that all of the radiant heat of the sub heater unit 47 is directed toward the soaking tube 14. .
[0028]
Since the heat insulating tank constituted by the first reflector and the second reflector has a very high heat insulating effect, the heat insulating material and the case outside the second reflector may be omitted. Moreover, although the 2nd reflector was comprised in the perimeter of space, you may comprise only in one side of the longitudinal direction of space.
[0029]
The heater as the heating element is not limited to being formed of molybdenum silicide, but may be formed of a metal heating element such as an Fe-Cr-Al alloy, or may be configured of a carbon lamp, a halogen lamp, or the like.
[0030]
The treatment can be used for heat treatment such as oxidation treatment, diffusion treatment, carrier activation after ion implantation, reflow for planarization, and annealing treatment.
[0031]
In the above embodiment, the oxidation / diffusion apparatus has been described. However, the present invention can be applied to all substrate processing apparatuses such as a CVD apparatus and an annealing apparatus.
[0032]
【The invention's effect】
According to the present invention, the temperature of the processing chamber can be raised and lowered efficiently, so that the total processing time can be shortened and energy saving can be realized.
[Brief description of the drawings]
FIG. 1 is a front cross-sectional view showing an oxidation / diffusion apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a main part.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Wafer (substrate), 10 ... Oxidation / diffusion apparatus (substrate processing apparatus), 11 ... Process tube, 12 ... Processing chamber, 13 ... Furnace, 14 ... Soaking tube, 14a ... Vent, 15 ... Vent DESCRIPTION OF SYMBOLS 16 ... Housing | casing, 17 ... Exhaust pipe, 18 ... Gas introduction pipe, 21 ... Seal cap, 22 ... Thermal insulation cap, 23 ... Holding member, 24 ... Thermal insulation board, 25 ... Sub heater unit, 26 ... Boat, 27 ... Holding member , 28 ... temperature sensor, 30 ... heater unit, 31 ... case, 32 ... heat insulating material, 33 ... heat insulating tank, 34 ... first reflector, 35 ... second reflector, 36 ... space, 37 ... supply pipe, 38 ... Exhaust pipe, 39 ... heater (heating element), 40 ... electric wire, 41 ... cooling air, 42 ... cooling air passage, 43 ... air supply pipe, 44 ... cover, 45 ... exhaust port, 46 ... exhaust path, 47 ... sub-heater Unit 51 ... Body 52 ... Surface 53 ... reflective coating film.

Claims (3)

In a substrate processing apparatus comprising a processing chamber for processing a substrate and a heater unit for heating the processing chamber,
The heater unit includes a heating element laid so as to surround the outside of the processing chamber, a first reflector laid so as to surround the heating element, and a space outside the first reflector. A second reflector laid on, an exhaust pipe for exhausting the space, and a supply pipe for supplying gas to the space,
A substrate processing apparatus, characterized in that a reflective coating film made of a multilayer coating film of silicon oxide or silicon nitride is deposited on the surfaces of the first reflector and the second reflector. A heating element laid to surround the outside of the processing chamber, a first reflector laid to surround the heating element, and a first laying to surround and surround the outside of the first reflector Two reflectors, and
  A process of processing a substrate in the processing chamber with a heater unit in which a reflective coating film composed of a multilayer coating film of silicon oxide or silicon nitride is deposited on the surfaces of the first reflector and the second reflector. When,
  Evacuating while supplying gas to the space;
  A substrate processing method comprising: A heating element laid to surround the outside of the processing chamber, a first reflector laid to surround the heating element, and a first laying to surround and surround the outside of the first reflector Two reflectors, and
  A process of processing a substrate in the processing chamber with a heater unit in which a reflective coating film composed of a multilayer coating film of silicon oxide or silicon nitride is deposited on the surfaces of the first reflector and the second reflector. When,
  Evacuating while supplying gas to the space;
  A method of manufacturing an IC, comprising:

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