Heating treatment apparatus and heating treatment method

Abstract

To provide a heating treatment apparatus and a heating treatment method which can suppress variation in the cooling time of plural workpieces, and obtain the workpieces with reduced variation in quality.SOLUTION: A heating treatment apparatus comprises: a chamber in which plural workpieces are stored and a cooling gas exhaust port is provided at a wall face, and which can maintain a reduced-pressure atmosphere; an exhaust part; a heating part which heats the plural workpieces; a cooling part which feeds a cooling gas to the workpieces; and a controller. The controller controls the exhaust part to reduce the pressure in the chamber, controls the heating part to heat the plural workpieces in the reduced-pressure atmosphere, and feeds a cooling gas to the plural workpieces after the heating to cool the same. The cooling gas is exhausted from the cooling gas exhaust port. The controller changes at least one of the feed timing of the cooling gas and the feed amount of the cooling gas according to the positions of the plural workpieces relative to the cooling gas exhaust port upon cooling the plural workpieces.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] Embodiments of the present invention relate to a heat treatment apparatus and a heat treatment method.

Background Art

[0002] There is a heat treatment apparatus that heats a workpiece to form a film or the like on the surface of the workpiece or processes the surface of the workpiece. In this case, the workpiece may be heated in an atmosphere whose pressure is reduced from atmospheric pressure.

[0003] For example, a heat treatment apparatus has been proposed that includes a chamber in which a workpiece is held, a plurality of heaters provided inside the chamber, and an exhaust device that reduces the internal pressure of the chamber to a pressure lower than atmospheric pressure. Further, in such a heat treatment apparatus, in order to improve the efficiency of the treatment, a plurality of workpieces may be stored side by side in the stacking direction inside the chamber. (For example, refer to Patent Document 1)

[0004] Here, since the workpiece subjected to the heat treatment is at a high temperature, it is cooled to a temperature at which it can be carried out of the inside of the chamber. For example, a cooling gas is supplied into the chamber to cool the temperature of the workpiece from about 400°C to 600°C to about 100°C. In this case, the cooling gas supplied into the chamber is discharged to the outside of the chamber from a cooling gas exhaust port provided in the chamber.

[0005] The cooling gas discharged from the cooling gas exhaust port is heated by the heat from the workpiece when the workpiece is cooled. Therefore, the cooling gas at a high temperature will gather in the vicinity of the cooling gas exhaust port.

[0006] When a plurality of workpieces are stored inside the chamber, the temperature of the atmosphere around the workpiece stored near the cooling gas exhaust port and the temperature of the atmosphere around the workpiece stored at a position away from the cooling gas exhaust port will be different. When the temperatures of the respective atmospheres are different, the temperature of the workpiece, and thus the cooling time for the workpiece to be cooled by the cooling gas below a certain temperature, will be different. If the cooling times of the workpieces vary, there is a risk that the quality of the processing will vary. Therefore, there has been a demand for the development of a technology that can suppress variations in the cooling times of a plurality of workpieces and thereby obtain workpieces with little variation in quality among the workpieces.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The problem to be solved by the present invention is to provide a heat treatment apparatus and a heat treatment method that can suppress variations in the cooling times of a plurality of workpieces and thereby obtain workpieces with little variation in quality among the workpieces.

Means for Solving the Problems

[0009] The heat treatment apparatus according to the embodiment includes a chamber in which a plurality of workpieces are stored, a cooling gas exhaust port provided on the wall surface, and capable of maintaining an atmosphere reduced in pressure from atmospheric pressure, an exhaust unit that decompresses the inside of the chamber to a predetermined pressure, a heating unit provided inside the chamber that heats the plurality of workpieces, a cooling unit that supplies cooling gas to the plurality of workpieces, and a controller that controls the exhaust unit, the heating unit, and the cooling unit. The controller controls the exhaust unit to decompress the internal pressure of the chamber to a predetermined pressure, controls the heating unit to heat the plurality of workpieces in the decompressed atmosphere inside the chamber, and controls the cooling unit to supply the cooling gas to the plurality of workpieces whose heating has ended to cool the plurality of workpieces. The cooling gas supplied to the plurality of workpieces is discharged from the cooling gas exhaust port to the outside of the chamber. When cooling the plurality of workpieces, the controller changes at least one of the supply timing of the cooling gas and the supply amount of the cooling gas according to the positions of the plurality of workpieces with respect to the cooling gas exhaust port.

Advantages of the Invention

[0010] According to the embodiment of the present invention, there are provided a heat treatment apparatus and a heat treatment method capable of suppressing variations in the cooling time of a plurality of workpieces, and thereby obtaining workpieces with little variation in quality among the workpieces.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments will be exemplified with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and detailed descriptions thereof are omitted as appropriate. Also, in each drawing, the X direction, the Y direction, and the Z direction represent three mutually orthogonal directions. For example, the X direction and the Y direction are horizontal directions. For example, the Z direction is the vertical direction (up-and-down direction).

[0013] Hereinafter, as an example, a heat treatment apparatus for heating a workpiece in an atmosphere depressurized from atmospheric pressure to form an organic film on the surface of the workpiece will be described. However, the present invention is not limited thereto. For example, the present invention can also be applied to a heat treatment apparatus for heating a workpiece in an atmosphere depressurized from atmospheric pressure to form an inorganic film or the like on the surface of the workpiece, or for treating the surface of the workpiece.

[0014] Also, the workpiece before heating may, for example, have a substrate and a solution applied to the surface of the substrate, or may be only the substrate. Hereinafter, as an example, the case where the workpiece before heating has a substrate and a solution applied to the surface of the substrate will be described.

[0015] In this case, the substrate is, for example, a glass substrate or a semiconductor wafer, etc. However, the substrate is not limited to the exemplified ones. The solution contains, for example, an organic material and a solvent. The organic material is not particularly limited as long as it can be dissolved by the solvent. The solution can be, for example, a varnish containing polyamic acid, etc. However, the solution is not limited to the exemplified ones. Also, the solution may be one in which the liquid has been pre-fired to a semi-cured state (a state where it does not flow).

[0016] FIG. 1 is a schematic front view for illustrating a heat treatment apparatus 1 according to the present embodiment. In FIG. 1, only one cassette 50 is drawn in order to avoid complication. FIG. 2 is a schematic cross-sectional view taken along the line A-A of the heat treatment apparatus 1 in FIG. 1. In FIG. 2, the cassette 50 is omitted in order to avoid complication. FIG. 3 is a schematic perspective view of the chamber 10 and the cassette rack 60.

[0017] As shown in FIGS. 1 and 2, the heat treatment apparatus 1 is provided with, for example, a chamber 10, an exhaust unit 20, a heating unit 30, a cooling unit 40, a cassette 50, a cassette rack 60, and a controller 70.

[0018] As shown in FIGS. 1 to 3, the chamber 10 has a box shape. The chamber 10 has an airtight structure capable of maintaining an atmosphere depressurized from the atmospheric pressure. As will be described later, a plurality of cassettes 50 (workpieces 100) are stored inside the chamber 10. A cooling gas exhaust port 17 is provided on the wall surface of the chamber 10. The external shape of the chamber 10 is not particularly limited. The external shape of the chamber 10 can be, for example, a rectangular parallelepiped or a cylinder. The chamber 10 is formed of, for example, a metal such as stainless steel.

[0019] For example, openings are provided at both ends of the chamber 10 in the Y direction. A flange 11 is provided at one end of the chamber 10 in the Y direction. A sealing material 12 such as an O-ring is provided on the flange 11. An opening / closing door 13 is provided on the side of the chamber 10 where the flange 11 is provided. When the opening / closing door 13 is closed, the opening of the chamber 10 is hermetically closed by the sealing material 12. When the opening / closing door 13 is opened, the workpiece 100 can be carried into or out of the cassette 50 through the opening of the chamber 10.

[0020] On the other end of the chamber 10 in the Y direction, a flange 14 is provided. A sealing material 12 is provided on the flange 14. A lid 15 is provided on the side of the chamber 10 where the flange 14 is provided. For example, the lid 15 is detachably attached to the flange 14 using a fastening member such as a screw. When the lid 15 is attached, the opening of the chamber 10 is closed airtight by the sealing material 12.

[0021] In addition, a cooling device (not shown) can be provided on the outer wall of the chamber 10. The cooling device can be, for example, a water jacket. If the cooling device is provided, it is possible to suppress the outer wall temperature of the chamber 10 from becoming higher than a predetermined temperature.

[0022] The exhaust section 20 evacuates the inside of the chamber 10 and reduces the pressure inside the chamber 10 to a predetermined pressure. As shown in FIG. 1, the exhaust section 20 has a first exhaust section 21 and a second exhaust section 22. The first exhaust section 21 and the second exhaust section 22 are connected to an exhaust port 16 provided on the bottom surface of the chamber 10.

[0023] The first exhaust section 21 has an exhaust pump 21a and a pressure control section 21b. The exhaust pump 21a can be an exhaust pump that performs rough evacuation from atmospheric pressure to a predetermined pressure. Therefore, the exhaust pump 21a has a larger exhaust volume than the exhaust pump 22a described later. The exhaust pump 21a can be, for example, a dry vacuum pump.

[0024] The pressure control section 21b is provided between the exhaust port 16 and the exhaust pump 21a. The pressure control section 21b controls the internal pressure of the chamber 10 to a predetermined pressure based on the output of a vacuum gauge (not shown) that detects the internal pressure of the chamber 10. The pressure control section 21b can be, for example, an APC (Auto Pressure Controller).

[0025] The second exhaust section 22 includes an exhaust pump 22a and a pressure control section 22b. After the rough evacuation by the exhaust pump 21a, the exhaust pump 22a further evacuates to a lower predetermined pressure. The exhaust pump 22a has, for example, an exhaust capacity capable of evacuating to the high-vacuum molecular flow region. For example, the exhaust pump 22a can be a turbo molecular pump (TMP), etc.

[0026] The pressure control section 22b is provided between the exhaust port 16 and the exhaust pump 22a. The pressure control section 22b controls the internal pressure of the chamber 10 to a predetermined pressure based on the output of a vacuum gauge (not shown) that detects the internal pressure of the chamber 10. The pressure control section 22b can be, for example, an APC, etc.

[0027] If the internal pressure of the chamber 10 is reduced, the heat released to the outside of the chamber 10 can be reduced. Therefore, the heating efficiency and the heat storage efficiency can be improved, so that the power applied to the heaters 33 and 36 described later can be reduced. If the power applied to the heaters 33 and 36 can be reduced, an increase in the load of the heaters 33 and 36 can be suppressed. Therefore, the service life of the heaters 33 and 36 can be extended.

[0028] The heating section 30 is provided inside the chamber 10 and heats a plurality of cassettes 50 (workpieces 100). The heating section 30 has, for example, a first heating section 31 and a second heating section 32. The first heating section 31 is provided above the cassette 50. The second heating section 32 is provided below the cassette 50. The second heating section 32 faces the first heating section 31.

[0029] The workpiece 100 is stored inside the cassette 50. Therefore, the first heating section 31 heats the surface (upper surface) of the workpiece 100 stored inside the cassette 50. The second heating section 32 heats the back surface (lower surface) of the workpiece 100 stored inside the cassette 50.

[0030] As shown in FIG. 1, when a plurality of cassettes 50 are arranged side by side in the Z direction (vertical direction) inside the chamber 10, the second heating unit 32 provided below the upper cassette 50 can be the first heating unit 31 provided above the lower cassette 50. That is, the first heating unit 31 or the second heating unit 32 provided between the cassettes 50 can be used in common.

[0031] For convenience, when focusing on one cassette 50, the upper side as viewed from that cassette 50 is the first heating unit 31, and the lower side is the second heating unit 32. However, heating units 30 can be provided above and below each of all the cassettes 50.

[0032] In this case, the back surface of the workpiece 100 stored inside the upper cassette 50 is heated by the first heating unit 31 or the second heating unit 32 that is used in common. The front surface of the workpiece 100 stored inside the lower cassette 50 is heated by the first heating unit 31 or the second heating unit 32 that is used in common. In this way, the number of the first heating unit 31 or the second heating unit 32 can be reduced. Therefore, reduction of power consumption, reduction of manufacturing cost, space saving, etc. can be achieved.

[0033] Each of the first heating unit 31 and the second heating unit 32 has, for example, a heater 33, a support portion 34, a holding portion 35, a heater 36, and a support portion 37.

[0034] As shown in FIGS. 1 and 2, a plurality of heaters 33 are provided. For example, a plurality of heaters 33 extending in the X direction and arranged in the Y direction can be provided. Note that the plurality of heaters 33 may extend in the Y direction and be arranged in the X direction. That is, the plurality of heaters 33 are arranged in a direction intersecting the central axis of the heater 33. However, an openable and closable door 13 and a lid 15 are provided at the Y-direction end of the chamber 10. Therefore, it is preferable that the plurality of heaters 33 extend in the X direction and are arranged in the Y direction. In this way, the opening and closing of the opening and closing door 13 and the lid 15 are facilitated, and the attachment and detachment of the plurality of heaters 33 are facilitated.

[0035] The plurality of heaters 33 may be arranged at equal intervals, or the intervals may be changed according to the temperature variation in the plane of the workpiece 100 or the like. For example, the heat of the workpiece 100 easily escapes to the outside from the end side of the workpiece 100 and hardly escapes to the outside from the central side of the workpiece 100. Therefore, the interval between the heaters 33 provided on the end side of the workpiece 100 can be made narrower than the interval between the heaters 33 provided on the central side of the workpiece 100.

[0036] Also, the specifications, number, intervals, etc. of the heaters 33 provided in the second heating section 32 may be the same as or different from the specifications, number, intervals, etc. of the heaters 33 provided in the first heating section 31. The specifications, number, intervals, etc. of the heaters 33 can be appropriately changed according to the composition of the solution to be heated (heating temperature of the solution), the dimensions of the workpiece 100 (planar dimensions) when viewed from the Z direction, etc. The specifications, number, intervals, etc. of the heaters 33 can be appropriately determined by performing simulations, experiments, etc.

[0037] The heater 33 has a rod shape and extends in one direction. The heater 33 is not particularly limited as long as it is a rod-shaped heater. The heater 33 can be, for example, a sheathed heater, a ceramic heater, a cartridge heater, etc. The heater 33 may have, for example, a quartz cover. In this specification, a "rod-shaped heater" also includes a heater covered with a quartz cover. Also, the external shape of the "rod shape" is not limited, and for example, it can be cylindrical, prismatic, or the like.

[0038] Further, the heater 33 is not limited to the above-described one as long as it can heat the workpiece 100 in an atmosphere depressurized from atmospheric pressure. That is, the heater 33 may be any one that extends in one direction and can release thermal energy by radiation.

[0039] As shown in FIGS. 1 and 2, the support portion 34 is provided inside the chamber 10. The support portion 34 supports the vicinity of one end of the heater 33 inside the chamber 10. The support portion 34 can be provided, for example, one for one heater 33 or one for a plurality of heaters 33.

[0040] The holding portion 35 holds the vicinity of the end of the heater 33 outside the chamber 10. The holding portion 35 can be attached to the outer surface of the chamber 10 using a fastening member such as a screw. The holding portion 35 detachably holds the vicinity of the end of the heater 33 on the terminal side. When the vicinity of the end of the heater 33 on the terminal side is held by the holding portion 35, the terminal of the heater 33 is exposed outside the chamber 10.

[0041] If the terminal of the heater 33 is exposed outside the chamber 10, maintenance of the heater 33 becomes easy. Also, when power is applied to the heater 33, it is possible to suppress the occurrence of vacuum discharge at the terminal of the heater 33.

[0042] Here, the heater 33 is provided to heat the entire area of the cassette 50 in which the workpiece 100 is stored. However, the heat of the workpiece 100 easily escapes to the outside from the peripheral side of the workpiece 100 and hardly escapes to the outside from the central side of the workpiece 100. Therefore, even if the entire area of the workpiece 100 is heated by the heater 33, the temperature of the peripheral region of the workpiece 100 becomes lower than the temperature of the central region of the workpiece 100. If the difference between the temperature of the peripheral region of the workpiece 100 and the temperature of the central region of the workpiece 100 becomes large, the quality of the film or the treatment layer formed on the surface of the workpiece 100 may deteriorate.

[0043] Therefore, the heat treatment apparatus 1 is provided with a heater 36. For example, the heater 36 heats the vicinity of the periphery of the cassette 50 in which the workpiece 100 is stored. The heater 36 can be provided in at least one of the first heating unit 31 and the second heating unit 32.

[0044] As shown in FIG. 2, the heater 36 is provided inside the chamber 10 so as to be arranged along the Y direction with the heater 33. The heater 36 has a rod shape and extends in one direction. The heater 36 is not particularly limited as long as it is a rod-shaped heater. As described above, the heater 33 heats the central region and the peripheral region of the heating region. The heater 36 heats the peripheral region of the heating region. Therefore, the length of the heater 36 is shorter than the length of the heater 33. The heater 36 can be the same as the heater 33 in other respects, for example.

[0045] The support portion 37 supports the tip side of the heater 36. The support portion 37 is attached to, for example, a beam provided on the cassette rack 60. The vicinity of the end portion on the terminal side of the heater 36 can be held by the holding portion 35 in the same manner as in the case of the heater 33. When the vicinity of the end portion on the terminal side of the heater 36 is held by the holding portion 35, the terminal of the heater 36 is exposed outside the chamber 10.

[0046] The cooling unit 40 supplies the cooling gas G to a plurality of workpieces 100. For example, the cooling unit 40 cooperates with a cooling unit 57 provided in a cassette 50 described later to supply the cooling gas G into the cassette 50. The cooling gas G supplied into the cassette 50 is supplied to the workpiece 100 stored inside the cassette 50. Further, the cooling gas G supplied into the cassette 50 is also supplied to the heat sinks of the cassette 50 (upper heat sink 52, lower heat sink 53, side heat sink 54, side heat sink 55), and is discharged into the chamber 10 through gaps between the heat sinks. The cooling gas G discharged into the chamber 10 is discharged to the outside of the chamber 10 from a cooling gas exhaust port 17 provided on the wall surface of the chamber 10. For example, an exhaust blower can be connected to the cooling gas exhaust port 17, or an exhaust pipe of a factory can be connected thereto. Details regarding the discharge of the cooling gas G through the cooling gas exhaust port 17 will be described later.

[0047] When the cooling gas G is supplied to the workpiece 100, the workpiece 100 in a high-temperature state is directly cooled. Further, when the cooling gas G supplied to the workpiece 100 is supplied to the heat sinks of the cassette 50, the cassette 50 is also cooled. By cooling the cassette 50, it is possible to suppress the heat of the cassette 50 from being transferred to the workpiece 100. Therefore, the workpiece 100 is also indirectly cooled by the cassette 50.

[0048]

[0049] The joint 41 is detachably connected, for example, to a joint 57c provided at one end of a pipe 57a of a cooling unit 57 provided in each cassette 50 described later. Alternatively, the joint 41 can be directly connected to one end of the pipe 57a. Note that the other end of the pipe 57a can be directly connected to the cassette 50, or can be connected to a plurality of nozzles (not shown) provided inside the cassette 50.​ The gas source 42 supplies the cooling gas G to the cooling part 57 of the cassette 50 via the gas control part 43 and the joint 41. The gas source 42 can be, for example, a high-pressure gas cylinder, factory piping, or the like. The cooling gas G is not particularly limited as long as it is a gas that hardly reacts with the heated workpiece 100. The cooling gas G is, for example, nitrogen gas, rare gas, or the like. The temperature of the cooling gas G can be, for example, room temperature (e.g., 25°C) or lower.

[0050] The gas control part 43 is provided between the joint 41 and the gas source 42. The gas control part 43 can perform, for example, control of at least any one of the start of supply of the cooling gas G, the stop of supply of the cooling gas G, the flow velocity and flow rate of the cooling gas G.

[0051] As shown in FIG. 1, the cassette 50 is detachably provided on a pair of receiving members 62 of a cassette rack 60 provided inside the chamber 10. The cassette 50 is detachably provided between the first heating part 31 and the second heating part 32.

[0052] FIG. 4 is a schematic perspective view for exemplifying the cassette 50. As shown in FIG. 4, the cassette 50 has a box shape and has a heating region inside which the workpiece 100 is heated. That is, the cassette 50 defines the heating region. There is no particular limitation on the external shape of the cassette 50. The external shape of the cassette 50 can be, for example, a rectangular parallelepiped.

[0053] The cassette 50 has, for example, a cassette frame 51, an upper soaking plate 52, a lower soaking plate 53, side soaking plates 54, side soaking plates 55, a workpiece support part 56, a cooling part 57, and a cassette support part 58.

[0054] The cassette frame 51 defines a heating region for heating the workpiece 100. The upper heat spreader 52 is plate-shaped and is provided at the upper part of the cassette frame 51. At least one upper heat spreader 52 can be provided. Seven upper heat spreaders 52 are provided in the cassette 50 illustrated in FIG. 4.

[0055] The lower heat spreader 53 is plate-shaped and is provided at the lower part of the cassette frame 51. The lower heat spreader 53 faces the upper heat spreader 52. At least one lower heat spreader 53 can be provided. The number and planar shape of the lower heat spreader 53 can be the same as or different from those of the upper heat spreader 52.

[0056] The side heat spreaders 54 are plate-shaped. A pair of side heat spreaders 54 can be provided. One of the side heat spreaders 54 is provided, for example, on one of the opposing sides of the cassette frame 51.

[0057] The workpiece 100 is carried into the inside of the cassette 50 through an opening provided in the side part of the cassette frame 51. Also, the workpiece 100 is carried out from the inside of the cassette 50 through an opening provided in the side part of the cassette frame 51. Therefore, one side part of the pair of side heat spreaders 54 of the cassette frame 51 may be open.

[0058] The opening of the cassette frame 51 is opened and closed, for example, by making one of the side heat spreaders 54 having the opening openable and closable. For example, a side heat spreader 54 can be provided on the opening and closing door 13 of the chamber 10 described above, and the opening of the cassette frame 51 can be closed by the side heat spreader 54 when the opening and closing door 13 is closed.

[0059] A pair of side heat spreaders 55 are provided inside the cassette frame 51 in a plate shape. The pair of side heat spreaders 55 face each other and extend in a direction intersecting the direction in which the side heat spreaders 54 extend.

[0060] The space surrounded by the upper heat sink 52, the lower heat sink 53, the side heat sink 54, and the side heat sink 55 becomes a heating region for heating the workpiece 100. The heating region inside the cassette 50 and the internal space of the chamber 10 are connected via, for example, the gaps between the heat sinks (the gaps between the beams of the cassette existing between the heat sinks and the heat sinks). Therefore, when the internal pressure of the chamber 10 is reduced, the pressure of the space inside the cassette 50 is also reduced. Further, the cooling gas G supplied to the space inside the cassette 50 is discharged to the internal space of the chamber 10 via the gaps between the heat sinks and the like.

[0061] Also, the heat radiated from the heaters 33 and 36 is incident on the upper heat sink 52 and the lower heat sink 53. The heat incident on the upper heat sink 52 and the lower heat sink 53 is radiated toward the workpiece 100 while propagating in the plane direction inside these heat sinks. Therefore, it is possible to suppress the occurrence of temperature variations within the plane of the workpiece 100.

[0062] A plurality of workpiece support portions 56 are provided inside the cassette 50. The plurality of workpiece support portions 56 support the back surface of the workpiece 100 in the heating region for heating the workpiece 100. The workpiece support portion 56 can be a rod-shaped body.

[0063] The cooling unit 57 supplies the cooling gas G supplied from the above-described cooling unit 40 to the workpiece 100 inside the cassette 50. The cooling unit 57 can be provided, for example, on the side surface of the cassette frame 51 of each cassette 50.

[0064] The cassette support portion 58 is provided on the side surface of the cassette frame 51 that intersects the side surface on which the side heat sink 54 is provided. A pair of cassette support portions 58 are provided. The cassette support portion 58 protrudes outward from the side surface of the cassette frame 51 and extends in a direction intersecting the side surface on which the side heat sink 54 is provided. The cassette support portion 58 is supported by a receiving member 62 of a cassette rack 60 described later.

[0065] As shown in FIG. 3, the cassette rack 60 is provided inside the chamber 10. The cassette rack 60 supports the heater 33, the heater 36, and the cassette 50 at predetermined positions inside the chamber 10.

[0066] The cassette rack 60 has, for example, a frame 61, a receiving member 62, and a reflector 63. The frame 61 has, for example, a framework structure. There is no particular limitation on the external shape of the frame 61. The external shape of the frame 61 can be, for example, a rectangular parallelepiped or a cylinder.

[0067] A plurality of receiving members 62 are provided inside the frame 61. The plurality of receiving members 62 are arranged in the Z direction at a predetermined interval. Also, in the X direction, a pair of receiving members 62 facing each other are provided. The cassette support portion 58 of the cassette 50 is placed on the pair of receiving members 62.

[0068] The reflector 63 reflects the incident heat toward the cassette 50 side. If the reflector 63 is provided, the heat storage property in the internal space (heating region) of the cassette 50 can be improved. The reflector 63 is plate-shaped and is provided on the outer periphery of the frame 61. Note that, to avoid complexity, the reflector 63 is not depicted in FIGS. 1 and 2. Also, in FIG. 3, only the reflector 63 attached to the side surface of the frame 61 to which the receiving member 62 is attached is depicted.

[0069] The controller 70 includes, for example, an arithmetic unit such as a CPU (Central Processing Unit) and a storage unit such as a memory. The controller 70 is, for example, a computer or the like. The controller 70 controls the operations of the respective elements provided in the heat treatment apparatus 1 based on, for example, a control program stored in the storage unit.

[0070] The controller 70 controls, for example, the exhaust unit 20, the heating unit 30, and the cooling unit 40 to execute the processing steps of the workpiece 100. FIG. 5 is a timing chart for illustrating the processing steps of the workpiece 100. As shown in FIG. 5, the processing steps of the workpiece 100 include, for example, a workpiece loading step, a temperature rising step, a heat treatment step, a cooling step, and a workpiece unloading step. The controller 70 can sequentially execute these steps based on the control program stored in the storage unit.

[0071] In the workpiece loading step, the controller 70 controls the opening / closing door 13 to separate the opening / closing door 13 from the flange 11. After the opening / closing door 13 is separated from the flange 11, the workpiece 100 is loaded into the cassette 50 by a transfer device (not shown). The workpiece 100 loaded into the cassette 50 is placed on the plurality of workpiece support portions 56.

[0072] Subsequently, the controller 70 controls the opening / closing door 13 to move the opening / closing door 13 to the flange 11 side to close the opening of the chamber 10 in an airtight manner. Subsequently, the controller 70 controls the exhaust unit 20 (the first exhaust unit 21 and the second exhaust unit 22) to reduce the internal pressure of the chamber 10 to a predetermined pressure. The predetermined pressure may be, for example, a pressure at which the polyamic acid in the solution does not react with the oxygen remaining in the internal space of the chamber 10 and is not oxidized when heated at a temperature of 300 °C or higher. The predetermined pressure may be, for example, about 1×10 -2 Pa to 100 Pa.

[0073] In the temperature rising step, the controller 70 controls the heating unit 30 to heat the plurality of workpieces 100 in the reduced-pressure atmosphere inside the chamber 10. For example, the controller 70 applies power to the heater 33 and the heater 36 to increase the temperature of the workpiece 100. In the processing steps of the workpiece 100 according to the present embodiment, two temperature rising steps (temperature rising steps (1) and (2)) are executed.

[0074] In the heat treatment step, the controller 70 controls the power applied to the heater 33 and the heater 36 to maintain the temperature of the workpiece 100 for a predetermined time. In the processing step of the workpiece 100 according to the present embodiment, since the temperature is raised twice, heat treatment steps (heat treatment steps (1) and (2)) are executed after each of the two temperature raising steps.

[0075] In the heat treatment step (1), for example, the workpiece 100 is heated at the first temperature for a predetermined time to discharge moisture, gas, etc. contained in the solution. The first temperature is, for example, about 100°C to 200°C. By performing the heat treatment step (1), it is possible to suppress moisture and gas contained in the solution from being contained in the organic film that is the finished product. Note that depending on the components of the solution, etc., the heat treatment step (1) can be performed multiple times with the temperature changed, or the heat treatment step (1) can be omitted.

[0076] In the heat treatment step (2), the solution from which moisture, gas, etc. have been discharged is treated at the second temperature for a predetermined time to form an organic film. The second temperature may be a temperature at which a polymerization reaction (imidization) occurs, for example, 300°C or higher. For example, if the second temperature is set to 400°C to 600°C, an organic film with a high degree of molecular chain packing can be obtained.

[0077] In the cooling step, the controller 70 stops applying power to the heater 33 and the heater 36. Then, the controller 70 controls the cooling unit 40 to supply the cooling gas G to the plurality of workpieces 100 that have finished heating to cool the plurality of workpieces 100. For example, the cooling gas G is supplied from the cooling unit 57 into the cassette 50. The workpiece 100 stored inside the cassette 50 is cooled by the cooling gas G supplied into the cassette 50. The cooling gas G supplied to the plurality of workpieces 100 is discharged from the cooling gas exhaust port 17 to the outside of the chamber 10.

[0078] In this case, the workpiece 100 is cooled to a temperature at which it can be carried out of the chamber 10. If the temperature of the cooled workpiece 100 is normal temperature, it becomes easy to carry out the workpiece 100. However, in the heat treatment apparatus 1, the workpiece 100 is continuously heat-treated. Therefore, if the temperature of the workpiece 100 is set to normal temperature every time the workpiece 100 is carried out, the time required to raise the temperature of the next workpiece 100 becomes longer. As a result, the productivity decreases. If the temperature of the cooled workpiece 100 is, for example, about 50°C to 100°C, the temperature of the elements provided inside the chamber 10 can also be set to the same level, so that it is possible to suppress the increase in the time required to raise the temperature of the next workpiece 100.

[0079] In the process of carrying out the workpiece, the controller 70 controls the opening / closing door 13 to separate the opening / closing door 13 from the flange 11. After the opening / closing door 13 is separated from the flange 11, the workpiece 100 is carried out from the inside of the cassette 50 by a conveying device (not shown).

[0080] Here, the discharge of the cooling gas G through the cooling gas exhaust port 17 will be further described. As described above, the cooling gas G supplied into the cassette 50 is discharged into the chamber 10 through the gaps between the soaking plates of the cassette 50. The inside of the chamber 10 is maintained in a state of being decompressed to a predetermined pressure by the exhaust unit 20, but the pressure gradually increases as the cooling gas G is supplied. When the pressure inside the chamber 10 approaches the atmospheric pressure due to the supply of the cooling gas G, as shown in FIG. 1, the cooling gas G discharged into the chamber 10 is discharged from the cooling gas exhaust port 17 provided on the wall surface of the chamber 10 to the outside of the chamber 10.

[0081] When the cooling gas G starts to be supplied into the chamber 10, the pressure inside the chamber 10 is a pressure reduced from the atmospheric pressure. At this point, almost no temperature difference occurs between the plurality of cassettes 50 (workpieces 100) provided inside the chamber 10. As the cooling gas G continues to be supplied and the amount of the cooling gas G in the chamber 10 increases, the pressure inside the chamber 10 gradually approaches the atmospheric pressure.

[0082] The cooling gas G is heated by the heat from the workpiece 100 when cooling the workpiece 100. When the inside of the chamber 10 approaches the atmospheric pressure, the heat taken from the workpiece 100 gradually accumulates above the chamber 10. That is, the atmosphere around the cassette 50 (workpiece 100) existing above the chamber 10 becomes a high temperature, and the workpiece 100 existing above becomes difficult to be cooled as compared with the workpiece 100 existing below. When the cooling gas exhaust port 17 is opened in this state, the hot cooling gas G remaining above the chamber 10 is discharged from the cooling gas exhaust port 17, and a flow of the cooling gas G with the heat taken from the workpiece 100 located below the chamber 10 toward the cooling gas exhaust port 17 occurs, so that the hot cooling gas G continues to pass above the chamber 10, and the workpiece 100 above the chamber 10 is still likely to be kept at a high temperature. That is, until the temperature of the workpiece 100 located below the chamber 10 decreases to a certain extent (until the cooling rate described later becomes low), the vicinity of the cooling gas exhaust port 17 is likely to be kept in an environment of a high temperature. Note that the adjustment is made so that the flow rate of the cooling gas G supplied into the chamber 10 from the cooling unit 57 is larger than the amount of the cooling gas G discharged from the cooling gas exhaust port 17.

[0083] Thus, when the hot cooling gas G gathers near the cooling gas exhaust port 17, the temperature of the atmosphere around the workpiece 100 stored near the cooling gas exhaust port 17 and the temperature of the atmosphere around the workpiece 100 stored at a position away from the cooling gas exhaust port 17 are different from each other.

[0084] For example, as shown in FIG. 1, when a plurality of workpieces 100 are arranged side by side in the stacking direction inside the chamber 10 and the cooling gas exhaust port 17 is provided on the ceiling of the chamber 10, due to the difference in the temperature of the atmosphere described above, the temperature of the uppermost workpiece 100 becomes higher than the temperature of the lowermost workpiece 100.

[0085] In this case, the arrangement of the cooling gas exhaust port 17 may be changed depending on the arrangement of other elements provided on the wall surface of the chamber 10. For example, the cooling gas exhaust port 17 may be provided on the bottom surface of the chamber 10 or may be provided on the side surface of the chamber 10.

[0086] In any case, after the cooling gas exhaust port 17 is opened, the workpiece 100 closest to the cooling gas exhaust port 17 will have the highest temperature. For example, in the configuration of the chamber 100 illustrated in FIG. 1, when the cooling gas exhaust port 17 is provided on the bottom surface of the chamber 10, the temperature of the lowermost workpiece 100 becomes higher than the temperature of the uppermost workpiece 100. When the cooling gas exhaust port 17 is provided on the side surface of the chamber 10, the temperature of the workpiece 100 closest to the cooling gas exhaust port 17 becomes higher than the temperature of the workpiece 100 farthest from the cooling gas exhaust port 17.

[0087] Due to the difference in the temperature of the atmosphere, if the temperature of the workpiece 100 is different, the cooling time of the workpiece 100 will also be different. For example, the time required for the temperature of the workpiece 100 with a high temperature to drop to a predetermined temperature is longer than the time required for the temperature of the workpiece 100 with a low temperature to drop to a predetermined temperature. If the cooling time of the workpiece 100 varies, there is a risk that the quality of the process will vary. For example, when the time required for the workpiece 100 to drop to a predetermined temperature becomes longer, the time during which the workpiece 100 is at a certain temperature (for example, 300°C) or higher becomes longer. As a result, the termination of the polymerization reaction that occurred in the heat treatment step (2) is delayed, and there is a risk that there will be a variation in the quality of the film formed between the workpiece 100 and other workpieces 100 (that is, workpieces 100 that require a relatively short time to drop to a predetermined temperature).

[0088] In this case, for each of the plurality of workpieces 100 stored inside the chamber 10, by supplying the cooling gas G and exhausting the cooling gas, the difference in the temperature of the atmosphere described above can be eliminated. FIG. 6 is a schematic diagram for exemplifying the cooling of the workpiece 100 according to the comparative example. As shown in FIG. 6, the cooling gas G can be supplied for each cassette 50 stored inside the chamber 10, and the cooling gas G can be exhausted from the cooling gas exhaust port 17 provided for each cassette 50 to the outside of the chamber 10. By doing so, the temperature of the atmosphere inside the cassette 50 can be made substantially the same. Therefore, it is possible to suppress the variation in the cooling time of the workpiece 100.

[0089] However, if this is done, since it is necessary to provide the cooling gas exhaust port 17 for each cassette 50, it will lead to complication of the configuration of the heat treatment apparatus and increase in cost.

[0090] Therefore, in the heat treatment apparatus 1 according to the present embodiment, when cooling the plurality of workpieces 100, the supply timing of the cooling gas G is changed according to the positions of the plurality of cassettes 50 (workpieces 100) with respect to the cooling gas exhaust port 17. Thereby, as shown in FIGS. 1 and 2, even when the cooling gas exhaust port 17 is provided only in the ceiling portion, it is possible to suppress the variation in the cooling time of the workpiece 100.

[0091] FIG. 7 is a timing chart for exemplifying the supply timing of the cooling gas G. As shown in FIG. 7, the controller 70 can delay the supply of the cooling gas G to the cassette 50 (workpiece 100) far from the cooling gas exhaust port 17 compared to the supply of the cooling gas G to the cassette 50 (workpiece 100) close to the cooling gas exhaust port 17. As described above, the ambient temperature around the cassette 50 (workpiece 100) far from the cooling gas exhaust port 17 is lower than the ambient temperature around the cassette 50 (workpiece 100) close to the cooling gas exhaust port 17. Therefore, by delaying the supply of the cooling gas G to the cassette 50 (workpiece 100) far from the cooling gas exhaust port 17 where the ambient temperature is low, it is possible to suppress variations in the cooling time of the workpiece 100.

[0092] In addition, when three or more cassettes 50 (workpieces 100) are provided inside the chamber 10, for example, the supply of the cooling gas G can be started sequentially from the cassette 50 (workpiece 100) closer to the cooling gas exhaust port 17. Also, according to the distance from the cooling gas exhaust port 17, a plurality of cassettes 50 (workpieces 100) can be divided into a plurality of groups, and the supply of the cooling gas G can be started sequentially from the cassettes 50 (workpieces 100) of the group closer to the cooling gas exhaust port 17. For example, among the plurality of cassettes 50 in the chamber 10, the upper half of the cassettes 50 can be set as a group close to the cooling gas exhaust port 17, and the lower half of the cassettes 50 can be set as a group far from the cooling gas exhaust port 17, and the supply timing of the cooling gas G can be controlled for each group. That is, the supply timing of the cooling gas G to the cassettes 50 belonging to the group far from the cooling gas exhaust port 17 is delayed compared to the supply timing of the cooling gas G to the cassettes 50 belonging to the group close to the cooling gas exhaust port 17. Alternatively, three or more groups corresponding to the position with respect to the cooling gas exhaust port 17 can be set, and the supply timing of the cooling gas G can be controlled for each group. Note that the supply timing of the cooling gas G can be appropriately set by conducting experiments or simulations.

[0093] As described above, by changing the supply timing of the cooling gas G according to the position of the cassette 50 (workpiece 100) relative to the cooling gas exhaust port 17, it is possible to reduce the temperature difference of the workpiece 100 at the beginning of the cooling process as shown in FIG. 5. Therefore, it is possible to suppress variations in the cooling time of the workpiece 100, and thereby obtain workpieces with little variation in quality among the workpieces 100.

[0094] In addition, when cooling a plurality of workpieces 100, the controller 70 can also change the supply amount of the cooling gas G according to the positions of the plurality of workpieces 100 relative to the cooling gas exhaust port 17. For example, the controller 70 can supply a larger amount of the cooling gas G to the cassette 50 (workpiece 100) closer to the cooling gas exhaust port 17 than to the cassette 50 (workpiece 100) farther from the cooling gas exhaust port 17. By doing so, cooling in the cassette 50 (workpiece 100) closer to the cooling gas exhaust port 17, where the ambient temperature is high, can be promoted, so that variations in the cooling time of the workpiece 100 can be suppressed.

[0095] In this case, during the period from the start of cooling to the end of cooling, the supply amount of the cooling gas G can remain constant, or can be increased stepwise or decreased stepwise, or can be increased gradually or decreased gradually. In addition, it is also possible to change the supply timing of the cooling gas G and change the supply amount of the cooling gas G.

[0096] Note that the change in the supply amount of the cooling gas G may be made for the supply amount of the cooling gas G supplied from nozzles (not shown) provided in the cooling unit 57, or may be made by changing the number of nozzles used with the supply amount of the cooling gas G supplied from each nozzle fixed. That is, the amount of the cooling gas G received by the cassette 50 (workpiece 100) may be changed. Also in this case, according to the distance from the cooling gas exhaust port 17, the plurality of cassettes 50 may be divided into a plurality of groups, and the supply amount of the cooling gas G may be controlled.

[0097] Here, the supply timing of the cooling gas G and the supply amount of the cooling gas G can be carried out based on predetermined set values. That is, these can be controlled by open-loop control. By doing so, simplification of the control program and reduction of manufacturing costs can be achieved.

[0098] On the other hand, the supply timing of the cooling gas G and the supply amount of the cooling gas G can also be controlled by feedback control. For example, a temperature sensor can be provided for each cassette 50, and based on the detected value of the temperature sensor, at least one of the supply timing of the cooling gas G and the supply amount of the cooling gas G can be changed. By performing feedback control, variations in the cooling time of the workpiece 100 can be further suppressed.

[0099] However, for example, as shown in part A of FIG. 5, at the beginning of the cooling of the workpiece 100, since the difference between the temperature of the workpiece 100 and the temperature of the cooling gas G is large, the cooling rate of the workpiece 100 becomes high. In contrast, as shown in part B of FIG. 5, when the cooling of the workpiece 100 progresses to a certain extent, the difference between the temperature of the workpiece 100 and the temperature of the cooling gas G becomes small, so the cooling rate of the workpiece 100 becomes low.

[0100] When feedback control is performed when the cooling rate of the workpiece 100 is high, it is necessary to frequently start and stop the supply of the cooling gas G and change the supply amount of the cooling gas G. Therefore, there is a risk that the accuracy of the feedback control decreases, the lifespan of the control valve or the like becomes short, or the control valve or the like malfunctions.

[0101] Therefore, it is preferable to perform open-loop control at the beginning of the cooling of the workpiece 100. And after the cooling of the workpiece 100 has progressed to a certain extent, the open-loop control can be switched to feedback control. That is, the controller 70 can switch at least one of the supply timing of the cooling gas G and the supply amount of the cooling gas G from open-loop control to feedback control based on the cooling rate of the workpiece 100.

[0102] The cooling rate of the workpiece 100 used for switching between open-loop control and feedback control can be obtained by conducting experiments or simulations in advance, or can be calculated based on the detection values from the temperature sensors provided for each cassette 50.

[0103] By switching between open-loop control and feedback control, it is possible to more effectively suppress the variation in the cooling time of the workpiece 100, and to suppress the reduction in control accuracy and the failure of control valves and the like.

[0104] Furthermore, for example, the supply amount of the cooling gas G may be controlled in advance to be changed in the time zone corresponding to part A and the time zone corresponding to part B in FIG. 5. Since the cooling rate of part A is high as described above, a difference in temperature change is likely to occur depending on the position of the workpiece 100. Also, the deviation in the stop timing of the polymerization reaction as described above can occur in the time zone corresponding to part A where the temperature of the workpiece 100 is still high. Therefore, in the time zone corresponding to part A, the supply amount of the cooling gas G supplied to the cassette 50 close to the cooling gas exhaust port 17 may be set to be large, and in the time zone corresponding to part B, the supply amount may be set to be less than that in the time zone corresponding to part A. That is, the supply amount of the cooling gas G may be increased at a timing when the temperature difference of the workpiece 100 is likely to affect the quality of the film, and may be decreased at a timing when it has relatively little effect on the quality of the film. Alternatively, in the first stage of the time period corresponding to section A, cooling gas G may not be supplied to cassette 50 that is far from the cooling gas exhaust port 17, and cooling gas G may be supplied to cassette 50 that is close to the cooling gas exhaust port 17. In the middle of the time period corresponding to section A, the supply of cooling gas G to cassette 50 that is far from the cooling gas exhaust port 17 may be started, and the flow rate of the cooling gas G supplied to cassette 50 that is close to the cooling gas exhaust port 17 may be increased. As described above, since the temperature difference (rate of temperature drop) of the workpiece 100 in the first stage of the time period corresponding to section A most affects the quality of the film, by controlling in this way, a cooling process corresponding to the position of the workpiece 100 can be more appropriately carried out, and variations in the quality of the formed film can be prevented.

[0105] As described above, the heat treatment method according to the present embodiment can have the following steps. A step of heating a plurality of workpieces 100 in a reduced-pressure atmosphere. A step of supplying cooling gas G to the plurality of heated workpieces 100 to cool the plurality of workpieces 100. And in the step of cooling the plurality of workpieces 100, the cooling gas G supplied to the plurality of workpieces 100 is discharged to the outside from the cooling gas exhaust port 17. Also, in the step of cooling the plurality of workpieces 100, at least one of the supply timing of the cooling gas G and the supply amount of the cooling gas G is changed according to the position of the workpiece 100 with respect to the cooling gas exhaust port 17.

[0106] Also, in the step of cooling the plurality of workpieces 100, the supply of the cooling gas G to the workpiece 100 that is far from the cooling gas exhaust port 17 can be delayed compared to the supply of the cooling gas G to the workpiece 100 that is close to the cooling gas exhaust port 17.

[0107] Also, in the step of cooling the plurality of workpieces 100, the supply amount of the cooling gas G to the workpiece 100 that is close to the cooling gas exhaust port 17 can be made larger than the supply amount of the cooling gas G to the workpiece 100 that is far from the cooling gas exhaust port 17.

[0108] Also, in the process of cooling a plurality of workpieces 100, at least one of the supply timing of the cooling gas G and the supply amount of the cooling gas G can be switched from open-loop control to feedback control based on the cooling rate of the workpiece 100. Note that the content of each step can be the same as that described above, and thus detailed description thereof will be omitted.

[0109] The embodiments have been illustrated above. However, the present invention is not limited to these descriptions. Regarding the above-described embodiments, those in which a person skilled in the art makes appropriate design changes are also included in the scope of the present invention as long as they have the features of the present invention. For example, the shape, dimensions, arrangement, etc. of each element included in the heat treatment apparatus 1 are not limited to those illustrated and can be changed as appropriate. Also, each element included in each of the above-described embodiments can be combined as much as possible, and those obtained by combining these are also included in the scope of the present invention as long as they include the features of the present invention.

Explanation of Reference Numerals

[0110] 1 Heat treatment apparatus, 10 Chamber, 17 Cooling gas exhaust port, 20 Exhaust section, 30 Heating section, 33 Heater, 36 Heater, 40 Cooling section, 50 Cassette, 60 Cassette rack, 70 Controller, 100 Workpiece, G Cooling gas

Claims

1. A chamber that houses a plurality of workpieces inside, has a cooling gas exhaust port provided on the wall surface, and can maintain an atmosphere depressurized from atmospheric pressure, an exhaust unit that depressurizes the inside of the chamber to a predetermined pressure, a heating unit provided inside the chamber that heats the plurality of workpieces, a cooling unit that supplies cooling gas to the plurality of workpieces, a controller that controls the exhaust unit, the heating unit, and the cooling unit, and is equipped with, the controller, controls the exhaust unit to depressurize so that the internal pressure of the chamber becomes a predetermined pressure, controls the heating unit to heat the plurality of workpieces in the depressurized atmosphere inside the chamber, controls the cooling unit to supply the cooling gas to the plurality of workpieces whose heating has ended to cool the plurality of workpieces, and the cooling gas supplied to the plurality of workpieces is discharged from the cooling gas exhaust port to the outside of the chamber, a heat treatment apparatus that, when cooling the plurality of workpieces, changes at least one of the supply timing of the cooling gas and the supply amount of the cooling gas according to the positions of the plurality of workpieces with respect to the cooling gas exhaust port.

2. The heat treatment apparatus according to claim 1, wherein the controller delays the supply of the cooling gas to the workpiece farther from the cooling gas exhaust port compared to the supply of the cooling gas to the workpiece closer to the cooling gas exhaust port.

3. The heat treatment apparatus according to claim 1 or 2, wherein the controller increases the supply amount of the cooling gas to the workpiece closer to the cooling gas exhaust port compared to the supply amount of the cooling gas to the workpiece farther from the cooling gas exhaust port.

4. The heat treatment apparatus according to claim 1 or 2, wherein the controller switches the control of at least one of the supply timing of the cooling gas and the supply amount of the cooling gas from open-loop control to feedback control based on the cooling rate of the workpiece.

5. A step of heating a plurality of workpieces in a depressurized atmosphere, a step of supplying cooling gas to the plurality of workpieces whose heating has ended to cool the plurality of workpieces, and is equipped with, in the step of cooling the plurality of workpieces, the cooling gas supplied to the plurality of workpieces is discharged to the outside from the cooling gas exhaust port, A heat treatment method for changing at least one of the supply timing of the cooling gas and the supply amount of the cooling gas according to the position of the work with respect to the cooling gas exhaust port.

6. The heat treatment method according to claim 5, wherein in the step of cooling the plurality of works, the supply of the cooling gas to the work far from the cooling gas exhaust port is delayed compared to the supply of the cooling gas to the work close to the cooling gas exhaust port.

7. The heat treatment method according to claim 5 or 6, wherein in the step of cooling the plurality of works, the supply amount of the cooling gas to the work close to the cooling gas exhaust port is made larger than the supply amount of the cooling gas to the work far from the cooling gas exhaust port.

8. The heat treatment method according to claim 5 or 6, wherein in the step of cooling the plurality of works, the control of at least one of the supply timing of the cooling gas and the supply amount of the cooling gas is switched from open-loop control to feedback control based on the cooling rate of the work.

Images