Heating treatment apparatus and heating treatment method

Abstract

To provide a heating treatment apparatus and a heating treatment method which can suppress deterioration in the quality of a workpiece when the workpiece is fed with a cooling gas and is cooled therewith.SOLUTION: A heating treatment apparatus comprises: a chamber stored with a workpiece at the inside; an exhaust part for decompressing the inside of the chamber; a heating part for heating the workpiece; and a cooling part for feeding a cooling gas to the workpiece. A controller controls the exhaust part to execute decompression so that the inner pressure of the chamber reaches a prescribed pressure, controls the heating part to heat the workpiece in an atmosphere where the inside of the chamber is decompressed, controls the cooling part to feed a cooling gas to the workpiece that has been heated so that the workpiece is cooled, further returns the inner pressure of the chamber to an atmospheric pressure to change the flow rate of the cooling gas in a period until the inner pressure of the chamber returns to the atmospheric pressure, and controls the cooling part to control the flow rate of the cooling gas so that an oxygen concentration in the chamber reaches an allowable oxygen concentration or lower based on the temperature of the workpiece changing with the feed of the cooling gas.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a heat treatment apparatus and a heat treatment method. [Background technology]

[0002] 2. Description of the Related Art There are heat treatment apparatuses that heat a workpiece in an atmosphere that is reduced in pressure below atmospheric pressure to form a film or the like on the surface of the workpiece or to treat the surface of the workpiece.

[0003] For example, a heat treatment device has been proposed that includes a chamber in which a workpiece is held, multiple heaters provided inside the chamber, an exhaust section that reduces the internal pressure of the chamber below atmospheric pressure, and a cooling section that cools the workpiece that has been subjected to heat treatment.

[0004] Here, the workpiece that has been subjected to heat treatment is at a high temperature. Therefore, the workpiece is cooled by a cooling unit so that the temperature of the workpiece can be removed from the inside of the chamber. For example, a heat treatment device equipped with a cooling unit that supplies cooling gas into the inside of the chamber has been proposed.

[0005] In this case, the cooling gas is supplied when the internal pressure of the chamber is returned to atmospheric pressure from a state where it has been reduced below atmospheric pressure, and for a predetermined period of time after the internal pressure of the chamber has returned to atmospheric pressure. In this case, if the flow rate of the cooling gas supplied when the internal pressure of the chamber is returned to atmospheric pressure from a state where it has been reduced below atmospheric pressure is increased, the cooling time of the workpiece can be shortened.

[0006] For this reason, a technique has been proposed in which the flow rate of the cooling gas supplied is increased when the internal pressure of the chamber is lower than atmospheric pressure, and the flow rate of the cooling gas supplied is decreased after the internal pressure of the chamber returns to atmospheric pressure (see, for example, Patent Document 1). This technique can shorten the cooling time and reduce the amount of cooling gas consumed.

[0007] However, if the flow rate of the cooling gas is increased when the internal pressure of the chamber is lower than atmospheric pressure, the workpiece is cooled rapidly, which tends to increase the temperature variation across the workpiece surface. If the temperature variation across the workpiece surface increases, the film formed on the workpiece surface may peel off, or the workpiece may become distorted, resulting in a decrease in the quality of the workpiece. Therefore, there has been a demand for the development of a technology that can prevent the quality of a workpiece from deteriorating when cooling the workpiece by supplying a cooling gas to the workpiece. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2019-205991 Summary of the Invention [Problem to be solved by the invention]

[0009] The problem that the present invention aims to solve is to provide a heat treatment device and a heat treatment method that can prevent deterioration in the quality of a workpiece when cooling the workpiece by supplying cooling gas to the workpiece. [Means for solving the problem]

[0010] A heat treatment apparatus according to an embodiment includes a chamber for storing a workpiece and capable of maintaining an atmosphere reduced in pressure below atmospheric pressure, an exhaust unit for reducing the pressure inside the chamber to a predetermined pressure, a heating unit provided inside the chamber for heating the workpiece, a cooling unit for supplying a cooling gas to the workpiece, and a controller for controlling the exhaust unit, the heating unit, and the cooling unit. The controller controls the exhaust unit to reduce the internal pressure of the chamber to a predetermined pressure, controls the heating unit to heat the workpiece in the reduced-pressure atmosphere inside the chamber, controls the cooling unit to supply the cooling gas to the workpiece after heating to cool it, and returns the internal pressure of the chamber to atmospheric pressure, changes the flow rate of the cooling gas during the period until the internal pressure of the chamber returns to atmospheric pressure, and controls the cooling unit to control the flow rate of the cooling gas so that the oxygen concentration in the chamber is equal to or lower than an allowable oxygen concentration based on the temperature of the workpiece that changes as the cooling gas is supplied. [Effects of the Invention]

[0011] According to an embodiment of the present invention, a heat treatment apparatus and a heat treatment method are provided that can suppress deterioration in the quality of a workpiece when cooling the workpiece by supplying a cooling gas to the workpiece. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic front view illustrating a heat treatment apparatus according to an embodiment of the present invention; [Figure 2] 2 is a schematic cross-sectional view of the heat treatment device in FIG. 1 taken along the line AA. [Figure 3] FIG. 2 is a schematic perspective view of a chamber and a cassette rack. [Figure 4] FIG. 2 is a schematic perspective view illustrating a cassette. [Figure 5] 1 is a timing chart illustrating a process for processing a workpiece. [Figure 6]10 is a graph illustrating the temperature of the workpiece, the internal pressure of the chamber, and the oxygen concentration in the chamber during the cooling process. [Figure 7] 4 is a timing chart illustrating the change in the flow rate of the cooling gas in the cooling step (1). [Figure 8] 10 is a timing chart illustrating the change in the flow rate of the cooling gas in the cooling step (2). DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments will be illustrated with reference to the drawings. In each drawing, similar components are denoted by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate. In each drawing, the X, Y, and Z directions represent three mutually orthogonal directions. For example, the X and Y directions are horizontal directions. For example, the Z direction is the up-down direction (vertical direction).

[0014] In the following, as an example, a heat treatment apparatus that heats a workpiece in an atmosphere reduced in pressure below atmospheric pressure to form an organic film on the surface of the workpiece will be described. However, the present invention is not limited to this. For example, the present invention can also be applied to a heat treatment apparatus that heats a workpiece in an atmosphere reduced in pressure below atmospheric pressure to form an inorganic film or the like on the surface of the workpiece or to treat the surface of the workpiece.

[0015] Furthermore, the work before heating may include, for example, a substrate and a solution applied to the surface of the substrate, or may be a substrate only. In the following, as an example, a case where the work before heating includes a substrate and a solution applied to the surface of the substrate will be described.

[0016] In this case, the substrate is, for example, a glass substrate or a semiconductor wafer. However, the substrate is not limited to the examples given. 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. However, the solution is not limited to the examples given. The solution may also be a liquid that has been pre-baked to a semi-hardened state (a state in which it does not flow).

[0017] FIG. 1 is a schematic front view illustrating a heat treatment device 1 according to the present embodiment. In FIG. 1, only one cassette 50 is shown to avoid complication. FIG. 2 is a schematic cross-sectional view of the heat treatment apparatus 1 in FIG. 1 taken along the line AA. In FIG. 2, the cassette 50 is omitted to avoid complication. FIG. 3 is a schematic perspective view of the chamber 10 and the cassette rack 60. As shown in FIG.

[0018] As shown in FIGS. 1 and 2, the heat treatment apparatus 1 includes, 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.

[0019] As shown in Figures 1 to 3, the chamber 10 is box-shaped. The chamber 10 has an airtight structure capable of maintaining an atmosphere at a reduced pressure below 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. There are no particular limitations on the external shape of the chamber 10. The external shape of the chamber 10 can be, for example, a rectangular parallelepiped or a cylinder. The chamber 10 is formed from a metal such as stainless steel.

[0020] 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 sealant 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 closed airtight by the sealant 12. When the opening / closing door 13 is opened, the workpiece 100 can be loaded into or loaded out of the cassette 50 through the opening of the chamber 10.

[0021] A flange 14 is provided at the other end of the chamber 10 in the Y direction. A sealant 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 airtightly by the sealant 12.

[0022] Furthermore, 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 a cooling device is provided, the temperature of the outer wall of the chamber 10 can be prevented from rising above a predetermined temperature.

[0023] The exhaust unit 20 exhausts the inside of the chamber 10 to reduce the pressure inside the chamber 10 to a predetermined level. 1, the exhaust unit 20 has a first exhaust unit 21 and a second exhaust unit 22. The first exhaust unit 21 and the second exhaust unit 22 are connected to an exhaust port 16 provided on the bottom surface of the chamber 10.

[0024] The first exhaust unit 21 includes an exhaust pump 21a and a pressure control unit 21b. The exhaust pump 21a may be an exhaust pump that performs rough exhaust from atmospheric pressure to a predetermined pressure. Therefore, the exhaust pump 21a has a larger exhaust volume than the exhaust pump 22a described below. The exhaust pump 21a may be, for example, a dry vacuum pump.

[0025] The pressure control unit 21b is provided between the exhaust port 16 and the exhaust pump 21a. The pressure control unit 21b controls the internal pressure of the chamber 10 to a predetermined pressure based on the output of a vacuum gauge (not shown) or the like that detects the internal pressure of the chamber 10. The pressure control unit 21b can be, for example, an APC (Auto Pressure Controller).

[0026] The second exhaust unit 22 includes an exhaust pump 22a and a pressure control unit 22b. The exhaust pump 22a exhausts the air to a lower predetermined pressure after the rough exhaust by the exhaust pump 21a. The exhaust pump 22a has an exhaust capacity capable of exhausting the air to a molecular flow region of a high vacuum. For example, the exhaust pump 22a can be a turbo molecular pump (TMP).

[0027] The pressure control unit 22b is provided between the exhaust port 16 and the exhaust pump 22a. The pressure control unit 22b controls the internal pressure of the chamber 10 to a predetermined pressure based on the output of a vacuum gauge (not shown) or the like that detects the internal pressure of the chamber 10. The pressure control unit 22b can be, for example, an APC.

[0028] If the internal pressure of the chamber 10 is reduced, the amount of heat released to the outside of the chamber 10 can be reduced. This improves the heating efficiency and heat storage efficiency, allowing the power applied to the heaters 33, 36, which will be described later, to be reduced. If the power applied to the heaters 33, 36 can be reduced, the load on the heaters 33, 36 can be prevented from becoming too high. This allows the life of the heaters 33, 36 to be extended.

[0029] The heating unit 30 is provided inside the chamber 10 and heats a plurality of cassettes 50 (workpieces 100). The heating section 30 includes, for example, a first heating section 31 and a second heating section 32 . The first heating unit 31 is provided above the cassette 50. The second heating unit 32 is provided below the cassette 50. The second heating unit 32 faces the first heating unit 31.

[0030] The workpiece 100 is stored inside the cassette 50. Therefore, the first heating unit 31 heats the front surface (top surface) of the workpiece 100 stored inside the cassette 50. The second heating unit 32 heats the back surface (bottom surface) of the workpiece 100 stored inside the cassette 50.

[0031] 1, when a plurality of cassettes 50 are arranged in the Z direction (vertical direction) inside the chamber 10, the second heating section 32 provided below the upper cassette 50 can serve as the first heating section 31 provided above the lower cassette 50. In other words, the first heating section 31 and the second heating section 32 provided between the cassettes 50 can be used as one heating section.

[0032] For convenience, when focusing on one cassette 50, the upper side of the cassette 50 is designated as the first heating section 31 and the lower side is designated as the second heating section 32, but heating sections 30 can be provided on the top and bottom of all cassettes 50.

[0033] In this case, the back surface of the workpiece 100 stored inside the upper cassette 50 is heated by the shared first heating unit 31 or second heating unit 32. The front surface of the workpiece 100 stored inside the lower cassette 50 is heated by the shared first heating unit 31 or second heating unit 32. In this way, it is possible to reduce the number of first heating sections 31 or second heating sections 32. This makes it possible to reduce power consumption, manufacturing costs, and space.

[0034] Each of the first heating section 31 and the second heating section 32 includes, for example, a heater 33, a support section 34, a holding section 35, a heater 36, and a support section 37.

[0035] 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 aligned in the Y direction can be provided. The plurality of heaters 33 may also extend in the Y direction and be aligned in the X direction. That is, the plurality of heaters 33 are aligned in a direction intersecting the central axes of the heaters 33. However, an openable / 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 be aligned in the Y direction. This facilitates opening and closing the openable door 13 and the lid 15, and facilitating installation and removal of the plurality of heaters 33.

[0036] The heaters 33 may be arranged at equal intervals, or the intervals may be changed depending on the temperature variation within the surface of the workpiece 100. For example, heat from the workpiece 100 is more likely to escape to the outside from the edge of the workpiece 100 and less likely to escape to the outside from the center of the workpiece 100. Therefore, the intervals between the heaters 33 provided on the edge of the workpiece 100 can be narrower than the intervals between the heaters 33 provided on the center of the workpiece 100.

[0037] Furthermore, the specifications, number, spacing, etc. of the heaters 33 provided in the second heating unit 32 may be the same as or different from the specifications, number, spacing, etc. of the heaters 33 provided in the first heating unit 31. The specifications, number, spacing, etc. of the heaters 33 can be changed as appropriate depending on the composition of the solution to be heated (heating temperature of the solution), the dimensions (planar dimensions) of the workpiece 100 when viewed from the Z direction, etc. The specifications, number, spacing, etc. of the heaters 33 can be determined as appropriate by performing simulations, experiments, etc.

[0038] The heater 33 is rod-shaped and extends in one direction. There are no particular limitations on the heater 33 as long as it is rod-shaped. The heater 33 may be, for example, a sheath heater, a ceramic heater, or a cartridge heater. The heater 33 may have, for example, a quartz cover. In this specification, the term "rod-shaped heater" includes heaters covered with a quartz cover. There are no limitations on the external shape of the "rod-shaped heater," and it can be, for example, a cylindrical or prismatic shape.

[0039] Furthermore, the heater 33 is not limited to the above-described heater as long as it can heat the workpiece 100 in an atmosphere that is reduced in pressure below atmospheric pressure. In other words, the heater 33 may be any heater that extends in one direction and can emit thermal energy by radiation.

[0040] 1 and 2, the support part 34 is provided inside the chamber 10. The support part 34 supports the vicinity of one end of the heater 33 inside the chamber 10. For example, one support part 34 can be provided for one heater 33, or one support part can be provided for multiple heaters 33.

[0041] The holding part 35 holds the vicinity of the end of the heater 33 outside the chamber 10. The holding part 35 can be attached to the outer surface of the chamber 10 using a fastening member such as a screw. The holding part 35 detachably holds the vicinity of the end of the heater 33 on the terminal side. When the holding part 35 holds the vicinity of the end of the heater 33 on the terminal side, the terminals of the heater 33 are exposed outside the chamber 10.

[0042] If the terminals of the heater 33 are exposed to the outside of the chamber 10, maintenance of the heater 33 is easy. Furthermore, when power is applied to the heater 33, it is possible to prevent vacuum discharge from occurring at the terminals of the heater 33.

[0043] Here, the heater 33 is provided to heat the entire area of ​​the cassette 50 in which the workpiece 100 is stored. However, heat from the workpiece 100 is likely to escape from the peripheral side of the workpiece 100 to the outside, but is difficult to escape from the center side of the workpiece 100 to the outside. Therefore, even if the entire area of ​​the workpiece 100 is heated by the heater 33, the temperature of the peripheral area of ​​the workpiece 100 will be lower than the temperature of the center area of ​​the workpiece 100. If the temperature difference between the peripheral area of ​​the workpiece 100 and the temperature of the center area of ​​the workpiece 100 becomes large, there is a risk that the quality of the film or treatment layer formed on the surface of the workpiece 100 will deteriorate.

[0044] Therefore, the heat treatment device 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 workpieces 100 are stored. The heater 36 can be provided in at least one of the first heating section 31 and the second heating section 32.

[0045] As shown in FIG. 2, the heater 36 is arranged inside the chamber 10, aligned with the heater 33 along the Y direction. The heater 36 is rod-shaped and extends in one direction. There are no particular limitations on the heater 36, as long as it is rod-shaped. As described above, the heater 33 heats the central region and 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 similar to the heater 33, for example, except for its length.

[0046] The support part 37 supports the tip side of the heater 36. The support part 37 is attached to, for example, a beam or the like provided on the cassette rack 60. The vicinity of the end part on the terminal side of the heater 36 can be held by the holding part 35, as in the case of the heater 33. When the vicinity of the end part on the terminal side of the heater 36 is held by the holding part 35, the terminals of the heater 36 are exposed to the outside of the chamber 10.

[0047] The cooling unit 40 supplies cooling gas to the plurality of workpieces 100. For example, the cooling unit 40 cooperates with a cooling unit 57 provided in the cassette 50, which will be described later, to supply cooling gas to the inside of the cassette 50. The cooling gas supplied to the inside of the cassette 50 is supplied to the workpieces 100 stored inside the cassette 50. The cooling gas supplied to the inside of the cassette 50 is also supplied to the heat equalizer plates (upper heat equalizer plate 52, lower heat equalizer plate 53, side heat equalizer plate 54, side heat equalizer plate 55), which will be described later, of the cassette 50, and flows into the inside of the chamber 10 through gaps between the heat equalizer plates, etc. The configuration of the cassette 50 will be described in detail later. The cooling gas discharged into the chamber 10 is maintained at a predetermined pressure by the exhaust unit 20, but the pressure gradually increases as the cooling gas is supplied. When the pressure inside the chamber 10 approaches atmospheric pressure due to the supply of cooling gas, the cooling gas is discharged to the outside of the chamber 10 through a cooling gas exhaust port 17 provided on the wall of the chamber 10. For example, an exhaust blower or a factory exhaust pipe can be connected to the cooling gas exhaust port 17.

[0048] Supplying the cooling gas to the workpiece 100 directly cools the workpiece 100, which is in a high temperature state. Furthermore, the cooling gas supplied to the workpiece 100 is also supplied to the heat equalizer plate of the cassette 50, thereby cooling the cassette 50 as well. Cooling the cassette 50 prevents 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.

[0049] 1 and 2, the cooling unit 40 includes, for example, a joint 41, a gas source 42, a gas source 43, a control valve 44, a control valve 45, and an on-off valve 46. The joint 41, the gas source 42, the gas source 43, the control valve 44, the control valve 45, and the on-off valve 46 are connected by a pipe 47.

[0050] The joint 41 is detachably connected to, for example, a joint 57c provided at one end of the piping of a cooling unit 57 provided in each cassette 50, which will be described later. Alternatively, the joint 41 can be directly connected to one end of the piping of the cooling unit 57. The other end of the piping of the cooling unit 57 can be directly connected to the cassette 50, or can be connected to a plurality of nozzles (not shown) provided inside the cassette 50. A joint 41 is provided for each of the plurality of cassettes 50.

[0051] The gas source 42 supplies a first cooling gas G1. The first cooling gas G1 is, for example, an inert gas. The inert gas is, for example, a rare gas such as nitrogen gas or helium gas, or a mixture of these gases. The gas source 42 is, for example, a high-pressure gas cylinder or factory piping. The temperature of the first cooling gas G1 can be, for example, room temperature (e.g., 25°C) or lower.

[0052] The gas source 43 supplies a second cooling gas G2. The second cooling gas G2 has a higher oxygen concentration than the first cooling gas G1. The second cooling gas G2 is, for example, clean dry air (CDA). The gas source 43 is, for example, factory piping. The temperature of the second cooling gas G2 can be, for example, room temperature (e.g., 25°C) or lower.

[0053] The control valve 44 is provided between the gas source 42 and the joint 41. The control valve 44 controls at least one of the flow rate and pressure of the first cooling gas G1 supplied from the gas source 42 to the cooling unit 57 provided in the cassette 50. The control valve 44 can also switch between starting and stopping the supply of the first cooling gas G1.

[0054] The control valve 45 is provided between the gas source 43 and the joint 41. The control valve 45 controls at least one of the flow rate and pressure of the second cooling gas G2 supplied from the gas source 43 to the cooling unit 57 provided in the cassette 50. The control valve 45 can also switch between starting and stopping the supply of the second cooling gas G2.

[0055] The on-off valve 46 is provided between the joint 41 and the control valve 44 and the control valve 45. The on-off valve 46 is provided for each of the joints 41 (for each of the cassettes 50). The on-off valve 46 switches between starting and stopping the supply of the first cooling gas G1, the second cooling gas G2, or the mixed gas of the first cooling gas G1 and the second cooling gas G2 for each of the cassettes 50.

[0056] It is also possible to supply the first cooling gas G1 and the second cooling gas G2 separately into the chamber 10 or the cassette 50, and mix the first cooling gas G1 and the second cooling gas G2 inside the chamber 10 or the cassette 50. However, doing so may cause unevenness or bias in the components of the mixed gas supplied to the workpiece 100.

[0057] 1, it is preferable to mix the first cooling gas G1 and the second cooling gas G2 outside the chamber 10 and supply the mixed first cooling gas G1 and second cooling gas G2 to the workpiece 100. In this way, it is possible to prevent unevenness or bias in the components of the mixed gas supplied to the workpiece 100, thereby improving the quality of the workpiece 100.

[0058] The mixing ratio of the first cooling gas G1 and the second cooling gas G2 can be controlled by, for example, control valves 44 and 45. Alternatively, a gas mixer may be provided between the gas source 42, the gas source 43, and the on-off valve 46, and the mixing ratio of the first cooling gas G1 and the second cooling gas G2 may be controlled by the gas mixer.

[0059] Furthermore, although the cooling unit 40 is exemplified as being capable of supplying at least one of the first cooling gas G1 and the second cooling gas G2, it is also possible to use a cooling unit that supplies only the first cooling gas G1 or a cooling unit that supplies only the second cooling gas G2. When using a cooling unit that supplies only the first cooling gas G1, the gas source 43 and the control valve 45 can be omitted. When using a cooling unit that supplies only the second cooling gas G2, the gas source 42 and the control valve 44 can be omitted. The cooling process of the workpiece 100, i.e., the supply of cooling gas, will be described in detail later.

[0060] 1, the cassette 50 is detachably mounted on a pair of receiving members 62 of a cassette rack 60 provided inside the chamber 10. The cassette 50 is detachably mounted between the first heating unit 31 and the second heating unit 32.

[0061] FIG. 4 is a schematic perspective view illustrating the cassette 50. As shown in FIG. As shown in Fig. 4, the cassette 50 is box-shaped and has a heating area therein for heating the workpiece 100. That is, the cassette 50 defines the heating area. There are no particular limitations on the external shape of the cassette 50. The external shape of the cassette 50 can be, for example, a rectangular parallelepiped.

[0062] The cassette 50 includes, for example, a cassette frame 51 , an upper heat equalizer plate 52 , a lower heat equalizer plate 53 , a side heat equalizer plate 54 , a side heat equalizer plate 55 , a workpiece support portion 56 , a cooling portion 57 , and a cassette support portion 58 .

[0063] The cassette frame 51 defines a heating area for heating the workpiece 100 . The upper heat equalizer plate 52 has a plate shape and is provided on the upper part of the cassette frame 51. At least one upper heat equalizer plate 52 can be provided. The cassette 50 illustrated in FIG. 4 is provided with seven upper heat equalizer plates 52.

[0064] The lower heat equalizer plate 53 has a plate shape and is provided below the cassette frame 51. The lower heat equalizer plate 53 faces the upper heat equalizer plate 52. At least one lower heat equalizer plate 53 can be provided. The number and planar shape of the lower heat equalizer plates 53 can be the same as or different from the number and planar shape of the upper heat equalizer plates 52.

[0065] The side heat equalizer plates 54 are plate-shaped. A pair of side heat equalizer plates 54 can be provided. One of the side heat equalizer plates 54 is provided, for example, on one of the opposing sides of the cassette frame 51.

[0066] The workpiece 100 is carried into the cassette 50 through an opening provided in the side of the cassette frame 51. The workpiece 100 is also carried out from the cassette 50 through an opening provided in the side of the cassette frame 51. Therefore, one side of the pair of side heat equalizing plates 54 of the cassette frame 51 may be open.

[0067] The opening of the cassette frame 51 is opened and closed by, for example, one of the side heat equalizer plates 54 having the opening, which can be opened and closed. For example, the side heat equalizer plate 54 can be provided on the opening door 13 of the chamber 10 described above, so that the opening of the cassette frame 51 is closed by the side heat equalizer plate 54 when the opening door 13 is closed.

[0068] The side heat equalizing plates 55 are plate-shaped and provided as a pair inside the cassette frame 51. The pair of side heat equalizing plates 55 face each other and extend in a direction intersecting the direction in which the side heat equalizing plates 54 extend.

[0069] The space surrounded by the upper heat equalizer plate 52, the lower heat equalizer plate 53, the side heat equalizer plate 54, and the side heat equalizer plate 55 is the heating region for heating the workpiece 100. The heating region inside the cassette 50 and the internal space of the chamber 10 are connected, for example, via gaps between the heat equalizer plates (gaps between the heat equalizer plates and the beams of the cassette between the heat equalizer plates). Therefore, when the internal pressure of the chamber 10 is reduced, the pressure in the internal space of the cassette 50 is also reduced. In addition, the cooling gas supplied to the internal space of the cassette 50 flows into the interior of the chamber 10 through gaps between the heat equalizer plates, etc.

[0070] Furthermore, the heat radiated from the heaters 33, 36 is incident on the upper heat equalizing plate 52 and the lower heat equalizing plate 53. The heat incident on the upper heat equalizing plate 52 and the lower heat equalizing plate 53 is propagated in the planar direction inside these plates and is then radiated toward the workpiece 100. Therefore, it is possible to suppress temperature variations within the surface of the workpiece 100.

[0071] A plurality of workpiece support portions 56 are provided inside the cassette 50. The plurality of workpiece support portions 56 support the rear surface of the workpiece 100 in a heating region where the workpiece 100 is heated. The workpiece support portions 56 may be rod-shaped.

[0072] The cooling unit 57 supplies the cooling gas supplied from the cooling unit 40 to the workpieces 100 in 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.

[0073] The cassette support parts 58 are provided on the side surface of the cassette frame 51 that intersects with the side surface on which the side heat equalizer plates 54 are provided. A pair of cassette support parts 58 are provided. The cassette support parts 58 protrude outward from the side surface of the cassette frame 51 and extend in a direction that intersects with the side surface on which the side heat equalizer plates 54 are provided. The cassette support parts 58 are supported by receiving members 62 of the cassette rack 60, which will be described later.

[0074] 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.

[0075] The cassette rack 60 includes, for example, a frame 61 , a receiving member 62 , and a reflector 63 . The frame 61 has, for example, a framework structure. 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 predetermined intervals. In addition, a pair of receiving members 62 facing each other in the X direction is provided inside the frame 61. The cassette support portions 58 of the cassette 50 are placed on the pair of receiving members 62. The reflecting plate 63 reflects the incident heat toward the cassette 50. The reflecting plate 63 has a plate shape and is provided on the outer periphery of the frame 61.

[0076] The controller 70 includes, for example, a calculation unit such as a CPU (Central Processing Unit) and a storage unit such as a memory. The controller 70 is, for example, a computer. The controller 70 controls the operation of each element provided in the heat treatment device 1 based on, for example, a control program stored in the storage unit.

[0077] The controller 70 controls, for example, the exhaust unit 20, the heating unit 30, and the cooling unit 40, and performs the processing steps for the workpiece 100. FIG. 5 is a timing chart illustrating the processing steps of the workpiece 100. In FIG. As shown in FIG. 5, the process of treating the workpiece 100 includes, for example, a workpiece carrying-in process, a temperature increasing process, a heat treatment process, a cooling process, and a workpiece carrying-out process. The controller 70 sequentially executes these steps based on a control program stored in the storage unit.

[0078] In the workpiece loading process, the controller 70 controls the door 13 to move the door 13 away from the flange 11. After the door 13 moves away from the flange 11, the workpiece 100 is loaded into the cassette 50 by a transport device (not shown). The workpiece 100 loaded into the cassette 50 is placed on a plurality of workpiece support portions 56.

[0079] Next, the controller 70 controls the opening / closing door 13 to move the opening / closing door 13 toward the flange 11, and closes the opening of the chamber 10 so that it is airtight. Next, 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 a pressure at which the polyamic acid in the solution does not react with oxygen remaining in the internal space of the chamber 10 and become oxidized when heated at a temperature of, for example, 400°C or higher. The predetermined pressure may be, for example, 1×10 -2 A pressure of about Pa to 100 Pa is sufficient.

[0080] In the temperature increasing 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 heaters 33 and 36 to increase the temperature of the workpieces 100. In the process of treating the workpiece 100 according to this embodiment, two temperature raising steps (temperature raising steps (1) and (2)) are performed.

[0081] In the heat treatment step, the controller 70 controls the power applied to the heaters 33 and 36 to maintain the temperature of the workpiece 100 for a predetermined time. In the processing step of the workpiece 100 according to this embodiment, two temperature-raising steps are performed, and therefore, heat treatment steps (heat treatment steps (1) and (2)) are performed after each of the two temperature-raising steps.

[0082] In the heat treatment step (1), for example, the workpiece 100 is heated at a first temperature for a predetermined time to remove moisture and gases 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 prevent the moisture and gases contained in the solution from being included in the finished organic film. Depending on the components of the solution, the heat treatment step (1) can be performed multiple times at different temperatures, or the heat treatment step (1) can be omitted.

[0083] In the heat treatment step (2), the solution from which moisture, gas, etc. have been removed is treated at a 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, 400°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.

[0084] In the cooling process, the controller 70 stops the application of power to the heaters 33 and 36. Then, the controller 70 controls the cooling unit 40 to supply cooling gas to the plurality of workpieces 100 after heating, thereby cooling the plurality of workpieces 100. For example, the cooling gas is supplied from the cooling unit 57 provided in the cassette 50 to the inside of the cassette 50. The cooling gas supplied to the inside of the cassette 50 cools the workpieces 100 stored inside the cassette 50. The cooling gas supplied to the plurality of workpieces 100 flows from the inside of the cassette 50 into the inside of the chamber 10 and is discharged to the outside of the chamber 10 from the inside of the cassette 50.

[0085] In this case, the workpiece 100 is cooled to a temperature at which it can be carried out of the chamber 10. Here, if the temperature of the cooled workpiece 100 is about room temperature, it is easy to unload the workpiece 100. However, in the heat treatment device 1, the workpiece 100 is continuously heat-treated. Therefore, if the temperature of the workpiece 100 is returned to about room temperature each time the workpiece 100 is unloaded, it takes a long time to heat the next workpiece 100. If the time required to heat the workpiece 100 is long, productivity will decrease. 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 made about the same, thereby preventing the time required to heat the next workpiece 100 from being long. Furthermore, if the temperature of the workpiece 100 is about 50°C to 100°C, the workpiece 100 can be unloaded from the chamber 10. Therefore, in the cooling process, it is preferable to lower the temperature of the workpiece 100 to about 50°C to 100°C.

[0086] In the workpiece unloading process, the controller 70 controls the opening / closing door 13 to move the opening / closing door 13 away from the flange 11. After the opening / closing door 13 moves away from the flange 11, the workpiece 100 is carried out from inside the cassette 50 by a conveying device (not shown).

[0087] Here, the supply of cooling gas in the cooling step will be further described. FIG. 6 is a graph illustrating the temperature of the workpiece 100, the internal pressure of the chamber 10, and the oxygen concentration in the chamber 10 during the cooling process. 6, A represents the change in temperature (° C.) of the workpiece 100. B represents the internal pressure (Pa) of the chamber 10. C and C1 represent the change in oxygen concentration (ppm) in the chamber 10.

[0088] C represents the change in oxygen concentration in a conventional cooling process, more specifically, the change in oxygen concentration when a cooling process is performed in which only the first cooling gas G1 is supplied until the pressure inside the chamber 10 reaches atmospheric pressure, and then the supply of the first cooling gas G1 is stopped and the second cooling gas G2 is supplied after the pressure inside the chamber 10 reaches atmospheric pressure. At this time, the flow rates of the first cooling gas G1 and the second cooling gas G2 are not changed during the cooling processes (1) and (2), and are always supplied at a constant rate.

[0089] C1 represents the change in oxygen concentration when the preferred cooling steps (1) and (2) of this embodiment are performed. More specifically, immediately after the start of the cooling step (1), a small amount of the first cooling gas G1 is supplied, and the supply flow rate of the first cooling gas G1 is gradually increased while a small amount of the second cooling gas G2 is mixed. The flow rate of the mixed second cooling gas G2 is gradually increased, and during the cooling step (2), the flow rate of the first cooling gas G1 is gradually decreased so that the proportion of the second cooling gas G2 contained in the cooling gas exceeds that of the first cooling gas G1. At this time, the total supply rate of the cooling gas is controlled to gradually increase, and the ratio of the first cooling gas G1 to the second cooling gas G2 is controlled to change during the cooling step (the cooling step will be described in detail below).

[0090] In the cooling process, when the cooling gas is supplied to the workpiece 100, as described above, the cooling gas supplied to the workpiece 100 flows out of the cassette 50 into the chamber 10. Therefore, as shown in B in Figure 6, the internal pressure of the chamber 10 returns to, for example, atmospheric pressure. After the internal pressure returns to atmospheric pressure, the cooling gas is discharged to the outside of the chamber 10 through the cooling gas exhaust port 17.

[0091] As shown in FIG. 6, in the cooling step, a cooling step (1) and a cooling step (2) are carried out in sequence. The cooling step (1) is performed, for example, during the period from when the internal pressure of the chamber 10 is reduced below atmospheric pressure to when it returns to atmospheric pressure (vacuum is broken). That is, in the cooling step (1), a cooling gas is supplied to the workpiece 100 after heating to cool the workpiece 100, and the internal pressure of the chamber 10 is returned to atmospheric pressure. The cooling step (2) is performed, for example, during a period after the internal pressure of the chamber 10 has returned to atmospheric pressure, and the workpiece 100 is cooled to a temperature (50 to 100°C) at which it can be carried out.

[0092] Here, if the internal pressure of the chamber 10 is lower than atmospheric pressure, heat is dissipated from the workpiece 100 by radiation. Therefore, as shown in A in Figure 6, the temperature of the workpiece 100 decreases more slowly in the cooling step (1) than in the cooling step (2).

[0093] In the cooling step (2), the internal pressure of the chamber 10 is atmospheric pressure, so heat is dissipated from the workpiece 100 by convection and radiation. Therefore, as shown in A in Figure 6, the rate at which the temperature of the workpiece 100 decreases tends to be faster in the cooling step (2) than in the cooling step (1).

[0094] Furthermore, when cooling gas is supplied to the workpiece 100 during the cooling process, the oxygen contained in the cooling gas increases the oxygen concentration in the chamber 10, as shown by C and C1 in FIG. 6. For example, clean dry air contains oxygen, so when clean dry air is supplied to the workpiece 100, the oxygen concentration in the chamber 10 increases. Also, even in the case of nitrogen gas or rare gas, even if the purity is said to be 100%, it actually contains oxygen at a level of several ppm. Therefore, even when nitrogen gas or rare gas is supplied to the workpiece 100, the oxygen concentration in the chamber 10 increases.

[0095] Here, as described above, if heat is dissipated from the workpiece 100 by radiation in the cooling step (1), the temperature of the workpiece 100 decreases more slowly, and the cooling time (cooling step time) of the workpiece 100 becomes longer. In this case, if the flow rate of the cooling gas supplied in the cooling step (1) is made greater than the flow rate of the cooling gas supplied in the cooling step (2), the time of the cooling step (1) can be shortened, and ultimately the cooling time of the workpiece 100 can be shortened.

[0096] However, doing so results in the workpiece 100 being rapidly cooled in the cooling step (1). When the workpiece 100 is rapidly cooled, for example, a difference in temperature is likely to occur between the area on the surface of the workpiece 100 to which the cooling gas is directly supplied and the area adjacent to this area. In other words, when the workpiece 100 is rapidly cooled, the temperature variation within the surface of the workpiece 100 becomes large.

[0097] As described above, the workpiece 100 may have a substrate and a film formed on the surface of the substrate. In such a case, if the temperature variation within the surface of the workpiece 100 becomes large, thermal stress caused by the difference in the thermal expansion coefficient of the materials may cause peeling of the film or distortion of the workpiece 100, which may result in a deterioration in the quality of the workpiece 100. Furthermore, even when the workpiece 100 is only a substrate, variations in temperature within the surface of the workpiece 100 can cause distortion or deformation in the workpiece 100, resulting in a deterioration in the quality of the workpiece 100.

[0098] Furthermore, when the flow rate of the cooling gas supplied in the cooling step (1) is set to a predetermined amount or more, and when the flow rate of the cooling gas supplied in the cooling step (2) is set to a predetermined amount or more, the oxygen concentration in the chamber 10 rises sharply, as shown in C in FIG. 6. When the oxygen concentration in the chamber 10 rises sharply, a reaction between the workpiece 100 and the cooling gas becomes more likely to occur. Here, the predetermined amount is the flow rate at which a reaction between the workpiece 100 and the oxygen gas contained in the cooling gas occurs, and varies depending on the temperature of the workpiece 100, the type of workpiece 100, and the type of cooling gas, but can be determined in advance by experiment, etc.

[0099] Therefore, in the heat treatment apparatus 1 according to the present embodiment, the flow rate of the cooling gas in the cooling step (1) is changed. FIG. 7 is a timing chart illustrating the change in the flow rate of the cooling gas in the cooling step (1). In the cooling step (1), the flow rate of the cooling gas can be gradually increased as shown by D1 and D2 in FIG. 7. In this case, the rate of increase of the flow rate of the cooling gas can be constant as shown by D1. Alternatively, the rate of increase of the flow rate of the cooling gas can be gradually increased as shown by D2. Alternatively, the rate of increase of the flow rate of the cooling gas can be increased in stages as shown by D3. That is, the flow rate of the cooling gas in the cooling step (1) can be increased over time.

[0100] In addition, the flow rate of the cooling gas in the cooling step (1) is gradually increased, and is set to be less than the predetermined amount previously determined by the above-mentioned experiment or the like, depending on the temperature of the workpiece 100 that gradually decreases due to the supply of the cooling gas.

[0101] In this way, it is possible to prevent the workpiece 100 from being rapidly cooled. Furthermore, since the flow rate of the cooling gas increases as the temperature of the workpiece 100 decreases, it is possible to prevent a decrease in the cooling efficiency even if the difference between the temperature of the workpiece 100 and the temperature of the cooling gas decreases over time.

[0102] C1 in Figure 6 shows the oxygen concentration when the flow rate of the cooling gas in the cooling step (1) described above is gradually increased while controlling the ratio of the first cooling gas G1 to the second cooling gas G2 so that it is less than a predetermined amount. As a basis for gradually increasing the flow rate of the cooling gas and for increasing the mixing ratio of the second cooling gas G2, cooling gas is supplied with a flow rate adjusted so that it is always less than a predetermined amount according to the temperature of the workpiece 100. If the increase in oxygen concentration in the chamber 10 is gradual, it becomes less likely that the workpiece 100 will react with the cooling gas, thereby improving the quality of the workpiece 100.

[0103] Therefore, it is possible to prevent the cooling time from becoming long, and also possible to prevent the quality of the workpiece 100 from deteriorating.

[0104] Furthermore, in the cooling step (2), the flow rate of the cooling gas can be increased over time, i.e., even after the internal pressure of the chamber 10 has returned to atmospheric pressure, the flow rate of the cooling gas can be increased over time. FIG. 8 is a timing chart illustrating the change in the flow rate of the cooling gas in the cooling step (2). In the cooling step (2), the flow rate of the cooling gas can also be gradually increased, as shown by D4 and D5 in FIG. 8. In this case, the rate of increase of the flow rate of the cooling gas can be constant, as shown by D4. Alternatively, the rate of increase of the flow rate of the cooling gas can be gradually increased, as shown by D5. Alternatively, the rate of increase of the flow rate of the cooling gas can be increased in stages, as shown by D6. In other words, the flow rate of the cooling gas in the cooling step (2) can be increased over time.

[0105] In this way, the workpiece 100 can be gradually cooled in the cooling step (2) as well. Furthermore, since the flow rate of the cooling gas increases as the temperature of the workpiece 100 decreases, it is possible to prevent a decrease in the cooling efficiency even if the difference between the temperature of the workpiece 100 and the temperature of the cooling gas decreases over time. Furthermore, as shown in A in Fig. 6, the temperature of the workpiece 100 becomes 400°C or less from the middle of the cooling step (2). In the present embodiment, when the temperature of the workpiece 100 becomes 400°C or less, a reaction between the workpiece 100 and the cooling gas is unlikely to occur. Therefore, once the temperature of the workpiece 100 becomes 400°C or less, the flow rate of the cooling gas may be increased without considering the oxygen concentration. By controlling in this manner, the quality of the workpiece 100 can be improved.

[0106] Therefore, in the cooling step (2), the cooling time can be prevented from becoming long, and the quality of the workpiece 100 can be prevented from deteriorating.

[0107] The temperature difference between the workpiece 100 and the cooling gas in the cooling step (1) is greater than the temperature difference between the workpiece 100 and the cooling gas in the cooling step (2). Therefore, it is preferable to increase the flow rate of the cooling gas in the cooling step (1) over time, and it is even more preferable to increase the flow rate of the cooling gas in the cooling step (1) and the cooling step (2) over time.

[0108] Furthermore, the flow rate of the cooling gas and the degree of increase in the flow rate can be changed as appropriate depending on the processing conditions in the heat treatment process (e.g., heating temperature, etc.) and the configuration of the workpiece 100 (e.g., whether or not a film is present, the material of the film, etc.). Furthermore, in the cooling step (2), the difference between the temperature of the workpiece 100 and the temperature of the cooling gas becomes small. Therefore, the control of increasing the flow rate of the cooling gas over time in the cooling step (2) can be omitted depending on the processing conditions in the heat treatment step and the configuration of the workpiece 100. For example, in the cooling step (2), the flow rate of the cooling gas may be kept constant.

[0109] The flow rate of the cooling gas, the rate of increase in the flow rate, and the necessity of controlling the flow rate of the cooling gas to increase over time in the cooling step (2) can be appropriately determined in advance by conducting experiments and simulations.

[0110] Furthermore, the temperature of the workpiece 100 in the cooling step (1) is higher than the temperature of the workpiece 100 in the cooling step (2). Therefore, it is preferable that the cooling gas used in the cooling step (1) is the first cooling gas G1, which is an inert gas. In this way, even if the temperature of the workpiece 100 is high, reaction between the workpiece 100 and the first cooling gas G1 can be suppressed.

[0111] In this case, the cooling gas used in the cooling step (2) can also be the first cooling gas G1. However, doing so increases the consumption of the first cooling gas G1, which is more expensive than the second cooling gas G2, and increases the manufacturing cost of the workpiece 100. Therefore, it is preferable to use the first cooling gas G1 as the cooling gas in the cooling step (1) and the second cooling gas G2 as the cooling gas in the cooling step (2). In this way, it is possible to improve the quality of the workpiece 100 and reduce the manufacturing cost.

[0112] Furthermore, depending on the processing conditions (e.g., heating temperature) in the heat treatment process and the configuration of the workpiece 100 (e.g., the presence or absence of a film, the material of the film, etc.), even if the second cooling gas G2 is used in the cooling process (1), it may be possible to suppress the reaction between the workpiece 100 and the second cooling gas G2. That is, by controlling the supply amount of the second cooling gas G2 based on a predetermined amount that varies depending on the type of workpiece 100, the temperature of the workpiece 100, and the type of cooling gas, as described above, the second cooling gas G2 can be supplied so that the oxygen concentration is below the allowable oxygen concentration (tolerable oxygen concentration), thereby suppressing the reaction between the workpiece 100 and the second cooling gas G2. In such cases, the cooling gas G2 can be used in the cooling process (1) and the cooling process (2). This can further reduce manufacturing costs. Whether the second cooling gas G2 can be used in the cooling process (1) can be determined in advance by conducting experiments or simulations.

[0113] The cooling gas used in the cooling step (1) can also be a mixed gas of the first cooling gas G1 and the second cooling gas G2. In this case, too, the ratio of the first cooling gas G1 to the second cooling gas G2 can be determined based on the predetermined amount described above. This reduces the consumption of the first cooling gas G1 and suppresses the reaction between the workpiece 100 and the cooling gas compared to using only the second cooling gas G2. In this case, the ratio of the second cooling gas G2 in the mixed gas can be increased over time. For example, the ratio of the first cooling gas G1 in the mixed gas can be increased immediately after the start of the cooling step (1), and the ratio of the second cooling gas G2 in the mixed gas can be increased as the end of the cooling step (2) approaches. This further suppresses the reaction between the workpiece 100 and the cooling gas. This is because, as the cooling step (1) progresses, the temperature of the workpiece 100 decreases. This decrease in temperature makes the workpiece 100 less susceptible to oxidation, increasing the allowable oxygen concentration and the predetermined amount described above.

[0114] Also, in the cooling step (2), a mixed gas of the first cooling gas G1 and the second cooling gas G2 can be used. In this way, the reaction between the workpiece 100 and the cooling gas can be suppressed compared to when only the second cooling gas G2 is used. Also, compared to when only the first cooling gas G1 is used, the manufacturing cost can be reduced.

[0115] The flow rate and mixing ratio of the mixed gas, and the timing for switching the flow rate and mixing ratio of the mixed gas, can be appropriately determined in advance by conducting experiments and simulations.

[0116] Furthermore, the reaction between the workpiece 100 and the cooling gas is affected by the temperature and material of the workpiece 100, and the proportion of oxygen contained in the cooling gas. Therefore, a sensor 48 that measures the oxygen concentration in the atmosphere inside the chamber 10 or cassette 50 and a sensor 49 that detects the temperature of the atmosphere are provided, and based on the temperature and oxygen concentration of the atmosphere, it is possible to switch between the first cooling gas G1 and the second cooling gas G2, or change the mixing ratio (oxygen proportion) of the first cooling gas G1 and the second cooling gas G2. Note that if the temperature of the workpiece 100 and the temperature drop state are known in advance, the sensor 49 that detects the temperature of the atmosphere can be omitted. That is, the controller 70 can change the oxygen concentration contained in the cooling gas based on the oxygen concentration measured by the sensor 48. That is, for example, the mixing ratio of the first cooling gas G1 and the second cooling gas G2 can be adjusted so that the oxygen concentration is equal to or less than an allowable oxygen concentration.

[0117] In this way, it is possible to further suppress the reaction between the workpiece 100 and the cooling gas, thereby improving the quality of the workpiece 100. Note that the reaction between the workpiece 100 and the cooling gas can be determined in advance by conducting experiments or simulations to determine the relationship between the ambient temperature, the oxygen concentration in the atmosphere, and the material of the workpiece 100.

[0118] Furthermore, the controller 70 can make the oxygen concentration of the cooling gas supplied to the workpiece 100 in the cooling step (1) lower than the oxygen concentration of the cooling gas supplied to the workpiece 100 in the cooling step (2). In this way, the reaction between the workpiece 100 and the cooling gas can be effectively suppressed, and the quality of the workpiece 100 can be further improved.

[0119] 1 illustrates an example in which the cooling gas is supplied to the cassette 50 provided inside the chamber 10, but the cooling gas may also be supplied to the inside of the chamber 10. Even in this case, the cooling gas supplied to the inside of the chamber 10 can be made to flow into the inside of the cassette 50, thereby cooling the workpiece 100. However, if the cooling gas is supplied to the inside of the cassette 50, the cooling gas can more easily reach the workpiece 100, thereby improving the cooling efficiency.

[0120] In some cases, the cassette 50 is not provided, and the workpiece 100 is directly supported inside the chamber 10. In such cases, a cooling gas may be supplied into the chamber 10. Cooling gas may also be supplied to the heaters 33, 36. Supplying cooling gas to the heaters 33, 36 cools the heaters 33, 36, thereby indirectly cooling the workpiece 100. This reduces the cooling time for the workpiece 100. For example, when supplying cooling gas into the chamber 10, the cooling gas may be arranged to reach the heaters 33, 36.

[0121] Even when the cooling gas is supplied to the inside of the chamber 10 or the cooling gas is supplied to the heaters 33 and 36, the cooling step (1) and the cooling step (2) described above can be performed.

[0122] As described above, the heat treatment method according to the present embodiment can include the following steps. A process of heating the workpiece 100 in an atmosphere reduced in pressure below atmospheric pressure. A process of supplying cooling gas to the workpiece 100 after heating to cool the workpiece 100. In the process of cooling the workpiece 100, the ambient pressure is returned to atmospheric pressure by supplying cooling gas to the workpiece 100, and the flow rate of the cooling gas is changed during the period until the ambient pressure returns to atmospheric pressure (cooling process (1)). The contents of each step can be the same as those described above, so detailed explanations will be omitted.

[0123] Although the embodiments have been described above, the present invention is not limited to these descriptions. Any design modifications made by a person skilled in the art to the above-described embodiments are also encompassed within the scope of the present invention as long as they include the features of the present invention. For example, the shape, dimensions, arrangement, etc. of each element included in the heat treatment device 1 are not limited to those exemplified and can be changed as appropriate. Furthermore, each element included in each of the above-described embodiments can be combined to the greatest extent possible, and such combinations are also included within the scope of the present invention as long as they include the features of the present invention. [Explanation of symbols]

[0124] REFERENCE SIGNS LIST 1 Heat treatment device, 10 Chamber, 20 Exhaust section, 30 Heating section, 33 Heater, 36 Heater, 40 Cooling section, 42 Gas source, 43 Gas source, 44 Control valve, 45 Control valve, 46 Opening / closing valve, 48 Sensor, 49 Sensor, 50 Cassette, 70 Controller, 100 Workpiece, G1 First cooling gas, G2 Second cooling gas

Claims

1. A chamber in which a workpiece is housed and which can maintain an atmosphere reduced to below atmospheric pressure, An exhaust section that reduces the pressure inside the chamber to a predetermined level, A heating unit is provided inside the chamber for heating the workpiece, A cooling unit that supplies cooling gas to the workpiece, A controller that controls the exhaust unit, the heating unit, and the cooling unit, Equipped with, The aforementioned controller, The exhaust section is controlled to reduce the pressure inside the chamber so that it becomes the predetermined pressure. The heating unit is controlled to heat the workpiece in a reduced-pressure atmosphere inside the chamber. The cooling unit is controlled to supply the cooling gas to the workpiece after heating is complete to cool the workpiece, and the internal pressure of the chamber is returned to atmospheric pressure. During the period until the internal pressure of the chamber returns to atmospheric pressure, the flow rate of the cooling gas is changed. A heating apparatus that controls the cooling unit and controls the flow rate of the cooling gas so that the oxygen concentration in the chamber is below the allowable oxygen concentration, based on the temperature of the workpiece which changes due to the supply of the cooling gas.

2. The heating apparatus according to claim 1, wherein the controller increases the flow rate of the cooling gas over time during the period until the internal pressure of the chamber returns to atmospheric pressure.

3. The heating apparatus according to claim 1 or 2, wherein the controller increases the flow rate of the cooling gas over time during the period after the internal pressure of the chamber has returned to atmospheric pressure.

4. The chamber further includes a sensor for measuring the oxygen concentration of the atmosphere inside the chamber. The heating apparatus according to claim 1 or 2, wherein the controller changes the oxygen concentration contained in the cooling gas based on the oxygen concentration measured by the sensor.

5. The heating apparatus according to claim 1 or 2, wherein the controller lowers the oxygen concentration of the cooling gas supplied to the workpiece during the period until the internal pressure of the chamber returns to atmospheric pressure, and lowers the oxygen concentration of the cooling gas supplied to the workpiece during the period after the internal pressure of the chamber returns to atmospheric pressure.

6. The heating apparatus according to claim 1 or 2, wherein the controller mixes a first cooling gas and a second cooling gas having a higher oxygen concentration than the first cooling gas outside the chamber, and supplies the mixed first cooling gas and second cooling gas to the workpiece as the cooling gas from the cooling unit.

7. The heating apparatus according to claim 6, wherein the controller controls the ratio of the first cooling gas to the second cooling gas so that the second cooling gas exceeds the first cooling gas during the period after the internal pressure of the chamber returns to atmospheric pressure.

8. A heating device for forming an organic film by heating a workpiece coated with a solution containing an organic material and a solvent, A chamber in which a workpiece is housed and which can maintain an atmosphere reduced to below atmospheric pressure, An exhaust section that reduces the pressure inside the chamber to a predetermined level, A heating unit is provided inside the chamber for heating the workpiece, A cooling unit that supplies cooling gas to the inside of the chamber, A controller that controls the exhaust unit, the heating unit, and the cooling unit, Equipped with, The cooling unit is configured to adjust at least one of the supply amount of the cooling gas and the proportion of oxygen contained in the cooling gas so as to change the proportion of oxygen contained in the cooling gas inside the chamber. The aforementioned controller, The exhaust section is controlled to reduce the pressure inside the chamber to the predetermined pressure, The heating unit is controlled to heat the workpiece in the reduced atmosphere inside the chamber. A heating apparatus that controls the cooling unit to supply the cooling gas to the inside of the chamber after heating has finished to cool the workpiece, and returns the inside of the chamber to atmospheric pressure, and during the period until the inside of the chamber returns to atmospheric pressure, increases the proportion of oxygen contained in the cooling gas inside the chamber to maintain an oxygen concentration that can suppress the reaction of the organic film on the workpiece with the oxygen contained in the cooling gas at that temperature, based on the temperature of the workpiece that has decreased due to the supply of the cooling gas.

9. A process of heating a workpiece in an atmosphere reduced to atmospheric pressure, A step of supplying cooling gas to the workpiece after heating is complete to cool the workpiece, Equipped with, A heat treatment method comprising the step of cooling the workpiece, wherein the cooling gas is supplied to the workpiece to return the pressure of the atmosphere to atmospheric pressure, the flow rate of the cooling gas is changed during the period until the pressure of the atmosphere returns to atmospheric pressure, and the flow rate of the cooling gas is controlled so that the oxygen concentration of the atmosphere is less than or equal to the allowable oxygen concentration, based on the temperature of the workpiece which changes due to the supply of the cooling gas.

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