JP7773402B2 - Detectors, heat treatment equipment - Google Patents

Description

The present invention relates to a detector and a heat treatment device.

A technology is known in which a solution containing an organic material and a solvent is applied to a substrate, which is then heated to form an organic film on the substrate. Specifically, the substrate (hereinafter referred to as the workpiece) coated with the solution is carried into a chamber and heat-treated at high temperatures of approximately 100°C to 600°C. Because no detectors existed that could function properly at such high temperatures, whether the heat treatment had finished and the workpiece had been removed from the chamber by a robot arm was inferred from the heat treatment time.

International Publication No. 2019/117250

However, if a malfunction occurs in the heat treatment time data, for example due to a short power outage, it can become impossible to determine whether or not a workpiece has been removed from the chamber. In such a case, the robot arm may mistakenly carry the next workpiece into the chamber even though the workpiece remains inside, raising the risk of the two colliding and causing cracks or chips. For this reason, there has been a long awaited development of a detector that can operate normally even inside the chamber, which becomes very hot during heat treatment.

The present invention aims to provide a detector that operates normally even inside a chamber that becomes hot during heat treatment. A heat treatment apparatus equipped with such a detector is also an aspect of the present invention.

The detector of the present invention is a detector that is provided inside a chamber in which a workpiece is heat-treated and that detects the workpiece being brought into the chamber, and is characterized in that it comprises a positive electrode wire made of metal, a negative electrode wire that is provided at a distance from the positive electrode wire and contains a metal different from that of the positive electrode wire, and a detection unit that is pressed against the workpiece to connect one end of the positive electrode wire to one end of the negative electrode wire, and the other end of the positive electrode wire and the other end of the negative electrode wire are provided outside the chamber.

The heat treatment apparatus of the present invention comprises a chamber into which a workpiece is carried, a heater provided inside the chamber to heat-treat the workpiece, and the aforementioned detector provided inside the chamber to detect the workpiece by being pressed against the workpiece.

The detector of the present invention can operate normally even inside a chamber that becomes very hot during heat treatment.

FIG. 2 is a plan view showing a workpiece according to the embodiment. 1 is a front view showing a heat treatment apparatus according to an embodiment; 1 is a partial cross-sectional view showing a heat treatment apparatus according to an embodiment; FIG. 2 is a perspective view showing a cassette according to an embodiment. FIG. 2 is a plan view showing a gas release portion of the embodiment. FIG. 2 is a diagram illustrating a detector according to an embodiment. FIG. 2 is a diagram illustrating an example of the arrangement of detectors according to the embodiment. FIG. 10 is a diagram illustrating another example of the arrangement of detectors according to the embodiment. FIG. 2 is a block diagram showing a control unit according to the embodiment. 10 is a flowchart showing the carrying-in and heating operation of the embodiment. 10 is a flowchart showing a cooling and carrying-out operation of the embodiment. 10 is a flowchart illustrating a detection operation according to the embodiment. FIG. 10 is a diagram illustrating yet another example of the arrangement of detectors according to the embodiment. 1A and 1B are diagrams illustrating a three-point support unit according to an embodiment.

[composition]
Hereinafter, an embodiment of the present invention (hereinafter also referred to as the present embodiment) will be described with reference to the drawings. First, a workpiece W to be heat-treated by a heat treatment apparatus 1 will be described, and then the heat treatment apparatus 1 will be described.

(Work)
As shown in FIG. 1, the workpiece W is a rectangular substrate S coated with a solution L. The solution L is made of a solvent containing an organic material, such as a varnish containing polyamic acid. The substrate S is, for example, a glass substrate or a semiconductor wafer, and the solution L is coated on the central portion but not on the peripheral portion. The substrate S is, for example, 1500 mm x 1850 mm in size, and the peripheral portion in this case is, for example, the area 10 mm inward from the four sides of the rectangular substrate S. The central portion is the area surrounded by such peripheral portions. Note that the ratio between the size of the workpiece W and the size of the area on the workpiece W to which the solution L is coated, as shown in FIG. 1, is different from the actual ratio, but this figure is used for ease of explanation.

The workpiece W is heat-treated in the heat treatment device 1, whereby the polyamic acid in the solution L is imidized, forming a polyimide film on the surface of the substrate S. Before being loaded into the heat treatment device 1, the workpiece W may be loaded into a pre-baking device (not shown) to form a pre-baked film. Pre-baking can be performed by leaving the workpiece W in an atmosphere of 90°C or less and a pressure of approximately 100 Pa for at least three minutes, for example, to evaporate some of the solvent from the solution L. The pre-baked film formed by evaporating some of the solvent from the solution L through pre-baking is treated the same as the solution L in the figures.

(Heat Treatment Apparatus)
2 and 3, the heat treatment apparatus 1 includes a chamber 10 into which the workpiece W is loaded and unloaded through an opening A, a cassette 20 provided inside the chamber 10 and on which the workpiece W is placed, a support unit 30 that supports the workpiece W via the cassette 20, and a heater 40 that heats the workpiece W. Furthermore, a detector 50 (see FIG. 6) that contacts the workpiece W and detects the presence or absence of the workpiece W inside the chamber 10 is detachably provided on the cassette 20. The detector 50 will be described in detail below.

In the following, the direction in which the workpiece W is loaded and unloaded through the opening A of the chamber 10 is referred to as the Y direction, the direction perpendicular to the Y direction on the placement surface of the chamber 10 is referred to as the X direction, and the direction perpendicular to the Y and X directions is referred to as the Z direction. In this embodiment, the chamber 10 is installed on a horizontal plane as shown in Figure 2, and the X direction is sometimes referred to as the left-right direction, the Y direction as the front-back direction, and the Z direction as the up-down direction. However, these directions do not limit the installation direction of the heat treatment device 1. Furthermore, the two surfaces that are aligned and facing each other in the X direction are sometimes referred to as side surfaces, and the two surfaces that are aligned and facing each other in the Z direction are sometimes referred to as the top and bottom surfaces.

Chamber 10 is a roughly rectangular parallelepiped container with an opening A on the front. Opening A is roughly rectangular, corresponding to the shape of chamber 10. Chamber 10 is made of a metal such as stainless steel.

Opposite the opening A is an opening/closing door D, driven by an opening/closing mechanism (not shown), which is slidable vertically between an open position and a closed position. When the opening/closing door D is in the open position, the opening A is opened, allowing the workpiece W to be loaded or unloaded. When the opening/closing door D is in the closed position, the opening A is closed. The opening/closing mechanism also switches the chamber 10 between a sealed state and an open state by moving the opening/closing door D back and forth from the closed position. In the sealed state, the opening/closing door D is pressed against the edge of the opening A, hermetically sealing the interior of the chamber 10. In the open state, there is a gap between the opening/closing door D and the edge of the opening A, leaving the interior of the chamber 10 open to the atmosphere. A seal such as an O-ring may be provided on the edge of the opening A that comes into contact with the opening/closing door D to improve airtightness.

An exhaust section 11 is provided in the chamber 10, for example, below it. One end of the exhaust section 11 is connected to the interior of the chamber 10, and the other end is connected to an exhaust device (not shown). This allows the exhaust section 11 to reduce the pressure inside the chamber 10 and create a vacuum when the interior of the chamber 10 is sealed. A vacuum is, for example, an atmosphere with a pressure of about 100 Pa, but is not limited to this.

An exhaust pipe 12 is provided in the chamber 10, for example, above it. One end of the exhaust pipe 12 is connected to the interior of the chamber 10, and the other end is connected to the outside of the chamber 10. A valve 121 is provided inside the exhaust pipe 12. The valve 121 is normally closed and is opened, for example, when a cooling gas (described below) is released into the chamber 10. As a result, the cooling gas released into the chamber 10 is exhausted to the outside via the exhaust pipe 12.

Cassettes 20 are arranged in multiple stages in the Z direction inside the chamber 10. In this embodiment, the workpiece W is carried into the chamber 10 and placed inside the cassette 20 through an opening 20a provided in the cassette 20. As shown in Figure 4, the cassette 20 is a box-shaped body that encloses the workpiece W placed inside on all four sides (top, bottom, left, and right) and on the side facing the opening 20a. In other words, the cassette 20 is a housing with a U-shaped cross section when viewed from the X direction. Note that the top surface of the cassette 20 is not shown in Figure 4 to simplify the explanation.

The cassette 20 comprises a cassette frame 21, a heat equalizer plate 22 attached to the cassette frame 21 and forming a box-shaped body, a workpiece support portion 23 that supports the underside of the workpiece W, and a cassette support portion 24 that allows the cassette 20 to be supported by the support portion 30 described below. Furthermore, as shown in Figure 3, the cassette 20 is removably provided with a gas discharge portion G that discharges cooling gas into the interior thereof.

The cassette frame 21 is a framework structure constructed, for example, using elongated members. The cassette frame 21 is, for example, a rectangular parallelepiped frame structure, with multiple beams 211 arranged in the X direction and spanning the Y direction on the top and bottom surfaces of the rectangular parallelepiped. There is no particular limitation on the number of beams 211, but in the following description it is assumed to be four.

The heat equalizer plates 22 are plate-shaped members made of a metal material with high thermal conductivity, such as stainless steel, and are provided on the top, bottom, left, right, and rear sides of the cassette frame 21. That is, by being provided on the top, bottom, left, right, and rear sides of the cassette frame 21, the heat equalizer plates 22 form the top, bottom, left, right, and rear surfaces of the box-shaped cassette 20. The rear side is the side opposite the side on which the opening A is provided in the Y direction. Specifically, multiple heat equalizer plates 22 are provided on the top and bottom of the cassette frame 21 to fill the spaces between each beam 211. In this embodiment, five heat equalizer plates 22 are provided on each of the top and bottom to fill the spaces between the outer frame of the cassette frame 21 and the four beams 211. One heat equalizer plate 22 is provided on each of the left, right, and rear sides of the cassette frame 21.

The work support portions 23 are rod-shaped bodies that protrude upward from the beams 211 on the underside of the cassette frame 21 and support the underside of the workpiece W at their tips. The arrangement and number of work support portions 23 are not particularly limited, but for example, four are provided at equal intervals on each beam 211. In other words, the work support portions 23 are provided in a 4 x 4 grid pattern on the underside of the cassette frame 21. The tips of the work support portions 23 are, for example, hemispherical in shape to prevent damage to the underside of the workpiece W.

The cassette support portion 24 is a protrusion that protrudes laterally from the side surface of the cassette 20 and is supported by the support portion 30 described below. The cassette support portion 24 is supported by the support portion 30, thereby supporting the cassette 20 on the support portion 30. Therefore, the workpiece W is directly supported by the workpiece support portion 23 of the cassette 20, and indirectly supported by the support portion 30. The cassettes 20 can be removed from the chamber 10 one by one, allowing for individual maintenance.

As shown in Figures 3 and 5, the gas release unit G is provided for each cassette 20 at the rear side of the cassette 20 and has piping extending in the X direction with multiple nozzles G1 at the tip of the piping. In other words, the gas release unit G is provided in multiple stages in the Z direction, corresponding to the position where the cassette 20 is supported by the receiving unit 32 described below, for example, and the piping connecting to the nozzles G1 provided on the cassette 20 is detachably connected to a gas supply device (not shown) provided outside the chamber 10 via a connection such as a joint (not shown). When the cassette 20 is removed for the aforementioned maintenance, the connection between the gas supply device and the gas release unit G can be detached.

Cooling gas is supplied to the gas discharge section G from this gas supply device. The temperature of the cooling gas is not particularly limited, but is, for example, lower than room temperature. The cooling gas may be, for example, nitrogen gas or a rare gas (such as argon gas or helium gas), as long as it is a gas that does not easily react with the heated workpiece W. In addition, multiple nozzles G1 protruding toward the opening A are provided on the side of the piping of the gas discharge section G, and the cooling gas is discharged from the openings of the nozzles G1. The openings of the nozzles G1 are, for example, directed between the underside of the workpiece W and the underside of the cassette 20. As a result, when cooling the interior of the chamber 10, the cooling gas discharged from the openings of the nozzles G1 flows along the underside of the workpiece W (see the dashed arrows in Figure 3). At this time, if opening A of the chamber 10 is open, the cooling gas is discharged from opening A. This creates a positive pressure inside the chamber 10, reducing the risk of particles entering the interior of the chamber 10 through opening A.

The support unit 30 includes a frame 31 erected inside the chamber 10 and a receiving unit 32 provided inside the frame 31 to support the cassette 20 (see Figure 2). The frame 31 is, for example, a framework structure constructed using elongated members. The frame 31 is, for example, a rectangular parallelepiped frame structure with plate-shaped inner walls on its sides. The receiving unit 32 is a pair of receiving members provided at the same height in the X direction on the inner wall of the frame 31. Each pair of receiving units 32 supports one cassette 20 by supporting the cassette support unit 24 of the cassette 20. The same number of pairs of receiving units 32 as the number of cassettes 20 are provided on the inner wall of the frame 31 in the Z direction. In this embodiment, as shown in Figures 2 and 3, six pairs of receiving units 32 are provided corresponding to six cassettes 20.

The heater 40 is, for example, a cylindrical member extending in the X direction. It radiates heat to heat the cassette 20, thereby heating the workpiece W placed inside the cassette 20. As shown in FIG. 3, multiple heaters 40 are arranged in a line in the Y direction. Furthermore, the multiple heaters 40 arranged in a line in the Y direction are arranged in multiple stages in the Z direction so as to sandwich the cassette 20 from above and below. That is, in this embodiment, seven stages of heaters 40 are provided corresponding to the six cassettes 20 supported inside the chamber 10.

As shown in Figure 6, the detector 50 is detachably mounted on the beam 211 of the cassette 20. The detector 50 comprises an insulator 51, an electrode portion 52, a holder 53, a detection portion 54, and a cap 55. When the detector 50 is pressed against the workpiece W inside the chamber 10 at high temperatures, the conductive portion 541 (described below) comes into contact with the electrode portion 52, generating an electromotive force due to the Seebeck effect. At this time, since the temperature inside the chamber 10 is high, a temperature difference occurs with a reference junction (not shown) outside the chamber 10, generating an electromotive force.

The insulator 51 is a plate-shaped base that is provided on the upper surface of the beam 211 and insulates the beam 211 from the electrode portion 52. The electrode portion 52 is disposed on the upper surface of the insulator 51.

The electrode section 52 consists of a positive electrode wire 521 and a negative electrode wire 522. The positive electrode wire 521 is made of a metal such as a nickel alloy primarily composed of nickel and chromium (hereinafter referred to as chromel, although this name does not limit the alloy's component ratios). The negative electrode wire 522 is made of a metal such as a nickel alloy primarily composed of nickel and aluminum (hereinafter referred to as alumel, although this name does not limit the alloy's component ratios). One end of the positive electrode wire 521 and one end of the negative electrode wire 522 are positioned with a specified gap between them, but are electrically connected by contacting a conductive section 541 made of chromel or alumel (described below). In other words, the positive electrode wire 521 and the negative electrode wire 522 are electrically connected via the conductive section 541. In this embodiment, the electrode unit 52 has one end of the positive electrode wire 521 and one end of the negative electrode wire 522 provided inside the chamber 10, and the other end of the positive electrode wire 521 and the other end (reference junction) of the negative electrode wire 522 provided outside the heat treatment device 1. When the temperature inside the chamber 10 is high and one end of the positive electrode wire 521 and one end of the negative electrode wire 522 come into contact via the detection unit 54, the Seebeck effect occurs, generating an electromotive force in the electrode unit 52. This electromotive force is detected by a voltmeter (not shown), and a signal is sent to a control device that controls a robot arm (not shown), which will be described later.

The holder 53 is positioned to cover the electrode unit 52 and is a holding member that holds the detection unit 54 above the electrode unit 52. The holder 53 includes a cylindrical holding unit 531 with a bottom and a flange 532 that extends from the lower side of the holding unit 531 in the direction along the beam 211 (Y direction). The bottom surface of the holding unit 531 has an opening 531a in the center, and in a plan view, one end of the positive electrode wire 521 and one end of the negative electrode wire 522 are visible through this opening 531a. The flange 532 has a groove F on the surface facing the insulator 51 that accommodates the positive electrode wire 521 and the negative electrode wire 522. The other ends of the positive electrode wire 521 and the negative electrode wire 522 extending from the groove F are pulled out of the chamber 10 through openings (not shown) provided in the chamber 10 and connected to a control device that controls a robot arm (not shown) described below via a voltmeter (not shown). In Figure 6, in order to illustrate the placement of the positive electrode wire 521 and negative electrode wire 522 in the groove F, the flange portion 532 is shown as being spaced apart from the insulator 51, but in reality, the flange portion 532 is placed on the insulator 51.

The detection unit 54 is held on the bottom surface of the holding unit 531 via spring B. The detection unit 54 includes a cylindrical metal conductive part 541 and a protective part 542 that covers the tip of the conductive part 541.

The conductive portion 541 is made of a metal such as chromel or alumel. That is, the conductive portion 541 is made of the same metal as either the positive electrode wire 521 or the negative electrode wire 522. The conductive portion 541 is inserted into spring B and protrudes from the lower and upper ends of spring B. The portion of the conductive portion 541 protruding from the lower end of spring B is inserted into opening 531a, and the biasing force of spring B positions the conductive portion 541 at a predetermined gap from one end of the positive electrode wire 521 and one end of the negative electrode wire 522. The opening 531a serves to guide the vertical movement of the conductive portion 541. The conductive portion 541 is supported by the holding portion 531 via opening 531a, ensuring reliable contact with the electrode portion 52.

The portion of the conductive portion 541 that protrudes from the upper end of the spring B is covered by the protective portion 542. The protective portion 542 is made of, for example, ceramic. The lower end of the protective portion 542 abuts against the upper end of the spring B. The tip of the protective portion 542 is, for example, hemispherical to prevent damage to the underside of the workpiece W it abuts. The weight of the workpiece W placed on the tip of the protective portion 542 presses against the detection portion 54, compressing the spring B. For this reason, it is preferable to position the tip of the protective portion 542 slightly higher than the tip of the workpiece support portion 23. In other words, it is preferable to ensure that the height position of the protective portion 542, which moves downward when the detection portion 54 is pressed by the workpiece W and the spring B compresses, is the same height as the workpiece support portion 23, so that the workpiece W can be reliably detected. When the workpiece W is placed on the tip of the protective portion 542, the lower end of the conductive portion 541 passes through the opening 531a and comes into contact with one end of the positive electrode wire 521 and one end of the negative electrode wire 522. This electrically connects the positive electrode wire 521 and the negative electrode wire 522 via the conductive portion 541. In other words, the positive electrode wire 521 and the negative electrode wire 522 are electrically connected via the conductive portion 541. At this time, the conductive portion 541 can be said to be part of the positive electrode wire 521 in the case of chromel, and part of the negative electrode wire 522 in the case of alumel. Therefore, the positive electrode wire 521 and the negative electrode wire 522 can be said to be in contact with each other via the conductive portion 541 as the two poles of the electrode portion 52.

When the inside of chamber 10 is hot and positive electrode wire 521 and negative electrode wire 522 come into contact, an electromotive force is generated in electrode 52 due to the temperature difference with the other end (reference junction) of the electrode (not shown) located outside chamber 10. This electromotive force is detected by a voltmeter (not shown), and the detection signal is transmitted to a control device that controls a robot arm (not shown) described below. In this way, detector 50 detects workpiece W inside chamber 10. For example, when processing of workpiece W is completed and workpiece W is removed, opening door D is open (opening A is open), and the temperature inside chamber 10 at this time is maintained at around 100°C, although it is lower than during heat treatment of workpiece W. Because the outside of chamber 10 is a clean room, the temperature is around 20-25°C, and there is a temperature difference between the inside and outside of chamber 10.

The cap 55 is provided on the upper surface of the flange portion 532 so as to cover the holding portion 531 from above. The cap 55 is hollow and cylindrical with an upper surface, and an opening 55a is provided in the center of the upper surface. The cap 55 covers the detection portion 54 so that the protective portion 542 is inserted into the opening 55a, preventing particles from entering the inside of the holding portion 531. The protective portion 542 protrudes from the outside of the cap 55. By placing the workpiece W on the upper end of this protective portion 542, the detector 50 can detect the workpiece W as described above. As mentioned above, the conductive portion 541 is guided by the opening 531a, so the opening 531a is made as small as possible. However, because the opening 55a of the cap 55 is located closer to the workpiece W than the opening 531a, if a large number of particles are generated due to friction between the conductive portion 541 and the opening 531a, the particles will adhere to the workpiece W. Therefore, the opening 55a is sized to prevent particles from being generated (i.e., large enough to prevent friction with the protective part 542). Alternatively, a metal diaphragm may be provided in the opening 55a to provide the protective part 542. This prevents particles generated inside the cap 55 from adhering to the workpiece W.

The detector 50 is provided on the beam 211 near the workpiece support portion 23, and the workpiece W, together with the workpiece support portion 23, abuts against the protective portion 542 of the detector 50. At least one detector 50 is provided for each cassette 20. The location at which the detector 50 is provided is not particularly limited, but for example, as shown in FIG. 7, the detector 50 is provided at the rear side of the leftmost beam 211. The detector 50 generates an electromotive force due to the temperature difference between the inside and outside of the chamber 10. Therefore, from the perspective of ensuring a temperature difference, it is preferable to provide the detector 50 on the rear side of the opening A of the chamber 10 (in a direction away from the opening A and the center of the chamber 10 in the Y direction). In short, it is sufficient that the detector 50 is provided in an area within the chamber 10 where a temperature difference between the inside and outside of the chamber 10 is reliably generated, even when the opening/closing door D is open.

However, the peripheral area of the substrate S of the workpiece W, where the solution L is not applied, is more susceptible to cracking and chipping than the central area where the solution L is applied, because the surface is not protected in any way. As a result, if the upper left portion of the workpiece W is chipped during heat treatment, for example, the detector 50 located directly below it will not be pressed by the workpiece W. If the detector 50 cannot detect the workpiece W, it will determine that the workpiece W is not present inside the chamber 10, and the workpiece W may be mistakenly brought into the chamber 10, potentially causing it to crack or chip due to a collision. To avoid such a situation, two or more detectors 50 may be provided for each cassette 20.

In this case, as shown in Figure 8, for example, a pair of detectors 50 are provided so as to abut against the underside of the diagonally opposite corners of the rectangular workpiece W. In the following, in the plane of Figure 8, the detector 50 provided so as to abut against the underside of the upper left corner of the workpiece W will be referred to as detector 50a, and the detector 50 provided so as to abut against the underside of the lower right corner of the workpiece W will be referred to as detector 50b. If both detectors 50a and 50b detect the workpiece W, it can be determined that "workpiece present." If only one of detectors 50a and 50b detects the workpiece W, it can be determined that "workpiece present" and "workpiece cracked." If neither detector 50a nor 50b detects the workpiece W, it can be determined that "workpiece not present."

The heat treatment apparatus 1 further includes a control unit 80 that controls the operation of each component. That is, the control unit 80 controls the opening/closing door D, the exhaust unit 11, the valve 121, the heater 40, and the gas release unit G. As shown in FIG. 9 , the control unit 80 includes an opening/closing control unit 81, an exhaust control unit 82, a heating control unit 83, a gas control unit 84, a memory unit 85, and an input/output control unit 86.

The opening/closing control unit 81 controls the opening/closing mechanism of the opening/closing door D. In other words, the opening/closing control unit 81 controls the movement of the opening/closing door D to the open position and the closed position, and controls the switching between the sealed state and the open state.

The exhaust control unit 82 controls the exhaust unit 11 to create a vacuum inside the sealed chamber 10. The exhaust control unit 82 also controls the opening and closing of the valve 121 of the exhaust pipe 12 to exhaust the cooling gas from inside the chamber 10.

The heating control unit 83 controls the output of the heater 40. By controlling the amount of power supplied to the heater 40, the output of the heater 40 can be controlled so that the interior of the chamber 10 is at a predetermined heat treatment temperature, for example, between 100°C and 600°C. The heating control unit 83 can also stop the power supply to the heater 40.

The gas control unit 84 controls whether or not cooling gas is released from the gas release unit G, i.e., controls the on/off state of the gas release unit G. When the gas release unit G is turned on, cooling gas is released from the opening of the nozzle G1. When the gas release unit G is turned off, cooling gas released from the opening of the nozzle G1 is stopped.

The memory unit 85 stores information such as programs and data for implementing the operation of each component controlled by the control unit 80. The input/output control unit 86 is an interface that controls signal conversion and input/output between each component controlled by the control unit 80.

Furthermore, an input device 91 and an output device 92 are connected to the control unit 80. The input device 91 is an input means such as a switch, touch panel, keyboard, or mouse that allows the operator to operate the heat treatment device 1 via the control unit 80. The output device 92 is an output means such as a display device that makes information for checking the status of the heat treatment device 1 visible to the operator.

[Operation]
(Loading and heating)
The loading and heating operation of the heat treatment apparatus 1 configured as described above will be described with reference to the flowchart in Fig. 10. It is assumed that a plurality of cassettes 20 are supported by the support parts 30 inside the chamber 10, and that no workpieces W are placed inside the cassettes 20. The opening A is in the closed position. However, there is a gap between the chamber 10 and the opening/closing door D, and the interior of the chamber 10 is open. As shown in Fig. 8, a pair of detectors 50 are provided so as to abut against the underside of the diagonally opposite corners of the workpieces W.

First, the opening/closing control unit 81 slides the opening/closing door D to the open position (step S01). Next, a robot arm (not shown) loads the workpieces W into the cassettes 20, starting from the top tier (step S02). The loaded workpieces W are supported by the workpiece support unit 23 and detector 50 provided inside the cassette 20. Once the workpieces W have been loaded, the opening/closing control unit 81 slides the opening/closing door D to the closed position and presses it against the opening A, sealing the interior of the chamber 10 (step S03).

After the interior of the chamber 10 is sealed, the exhaust control unit 82 controls the exhaust unit 11 to depressurize the interior of the chamber 10 (step S04). For example, the pressure is reduced to approximately 100 Pa. After the interior of the chamber 10 is depressurized to a predetermined pressure and reaches a vacuum state, the interior of the chamber 10 is maintained at a vacuum. Next, the heating control unit 83 supplies power to the heater 40 so that the interior of the chamber 10 reaches a predetermined heat treatment temperature, and heat treatment is performed on the workpiece W (step S05). The heat treatment temperature is, for example, 100°C to 600°C, but is not particularly limited. Note that power supply to the heater 40 may be started from step S03, thereby gradually heating the interior of the chamber 10. After heat treatment of the workpiece W is completed, the heating control unit 83 stops the power supply to the heater 40 (step S06).

(Cooling and removal operation)
Next, the cooling and unloading operation of the heat treatment apparatus 1 will be described with reference to the flowchart of FIG. 11 . It is assumed that the heating time of the heater 40 has ended and the power supply to the heater 40 has been stopped. First, exhaust from the exhaust unit 11 is stopped, and the gas release unit G is turned on by the gas control unit 84 (step S11). This gradually changes the pressure inside the chamber 10 from vacuum to atmospheric pressure, and cools the heat equalizer plate 22 and the workpiece W. Cooling the heat equalizer plate 22 that constitutes the cassette 20 prevents heat from being transferred from the heat equalizer plate 22 to the workpiece W, allowing the workpiece W to be efficiently cooled by the cooling gas.

Once the pressure inside the chamber 10 reaches atmospheric pressure, the exhaust control unit 82 opens the valve 121 and exhausts the cooling gas to the outside of the chamber 10 through the exhaust pipe 12 (step S12). This cools the inside of the chamber 10 to a predetermined temperature while maintaining atmospheric pressure. The predetermined temperature is, for example, 100°C or below. A sensor (not shown) may be used to detect whether the temperature inside the chamber 10 is below the predetermined temperature. Alternatively, the temperature may be controlled based on an optimal time determined in advance through experiments, etc. Note that if opening A of the chamber 10 is left open as shown in step S13 below before the predetermined temperature is reached, the oxygen flowing into the chamber 10 through opening A may react with the components of the film formed on the substrate S of the workpiece W, potentially resulting in a workpiece W that does not have the desired film quality.

When the interior of the chamber 10 is cooled to a predetermined temperature under atmospheric pressure in step S12, the opening/closing control unit 81 controls the opening/closing door D to open the interior of the chamber 10, and then slides the opening/closing door D to the open position (step S13). Next, a robot arm (not shown) unloads the workpieces W, starting from the cassette 20 on the lower level (step S14). The time when the workpieces W are unloaded is determined based on the heat treatment time, as described above. For example, the time when the workpieces W are unloaded can be determined by adding the heat treatment time to the time required to unload the workpieces W, based on the start of the heat treatment. A timer can be started from the time when the workpieces W are unloaded, and depending on whether a predetermined time has elapsed, it can be determined whether the next workpiece W should be loaded into the chamber 10 and the detector 50 should detect the workpieces W.

(Detection operation)
Next, the detection operation of the heat treatment apparatus 1 with the detector 50 arranged as shown in FIG. 8 will be described with reference to the flowchart of FIG. 12. At the time of unloading the workpiece W (after step S14 in FIG. 11), before the next workpiece W to be heat-treated is loaded into the chamber 10, it is detected whether the workpiece W remains inside the chamber 10 (step S21). Specifically, it is confirmed whether the detectors 50a and 50b have detected the workpiece W. At this time, the temperature inside the chamber 10 is below 100°C. Even if the opening/closing door D is open, the temperature inside the chamber 10 does not drop suddenly, and there is a temperature difference of about 50°C between the outside and the inside of the chamber 10. Alternatively, when the opening/closing door D is opened, the heater 40 may be turned on to prepare for the next temperature rise. This reliably maintains the temperature difference between the inside and outside of the chamber 10, allowing the detector 50 to reliably detect the workpiece W. If neither detector 50a nor 50b detects the workpiece W (NO in step S21), it is determined that there is no workpiece inside the chamber 10, and the workpiece W to be heat-treated next is loaded using a robot arm (not shown).

On the other hand, if at least one of the detectors 50a and 50b detects a workpiece W (YES in step S21), it is determined that a workpiece is present inside the chamber 10. In this case, the loading of the workpiece W to be heat-treated next is temporarily stopped. It is also possible to determine whether the workpiece W remaining inside the chamber 10 is cracked (step S22). That is, if both detectors 50a and 50b detect the workpiece W (YES in step S22), the workpiece W is determined to be "uncracked." In this case, after a predetermined time has elapsed (step S23), the process returns to step S21. If the workpiece W has been unloaded at this point, the process proceeds to YES in step S21, and the workpiece W to be heat-treated next is loaded. On the other hand, if only one of the detectors 50a and 50b detects the workpiece W (NO in step S22), the workpiece W is determined to be "cracked." In this case, it is likely that pieces of the workpiece W remain inside the cassette 20, so even if the workpiece W is removed after a predetermined time has passed, it is likely that pieces of the workpiece W remain inside the cassette 20, and these pieces must be removed.

[Action and effect]
(1) The detector 50 of this embodiment is provided inside the chamber 10 in which the workpiece W is heat-treated, and is pressed against the workpiece W being carried into the chamber 10. The detector 50 includes a positive electrode wire 521 made of metal, a negative electrode wire 522 that is provided at a distance from the positive electrode wire 521 and made of a different metal than the positive electrode wire 521, and a detection unit 54 that conducts one end of the positive electrode wire 521 and one end of the negative electrode wire 522 when pressed against the workpiece W, and the other end of the positive electrode wire 521 and the other end of the negative electrode wire 522 are provided outside the chamber 10. The positive electrode wire 521 and the negative electrode wire 522, both made of metal, are heat-resistant, and therefore can detect the presence or absence of the workpiece W even inside the chamber 10 at high temperatures of 100°C to 600°C.

(2) The detection unit 54 of this embodiment is provided at a distance from the positive electrode wire 521 and the negative electrode wire 522 and includes a conductive portion 541 made of the same metal as either the positive electrode wire 521 or the negative electrode wire 522. When pressed against the workpiece W, the detection unit 54 establishes electrical continuity between one end of the positive electrode wire 521 and one end of the negative electrode wire 522 via the conductive portion 541. This makes it possible to bring the positive electrode wire 521 and the negative electrode wire 522 into contact without moving them, thereby improving the durability of the detector 50.

(3) The positive electrode wire 521 is made of a nickel alloy primarily composed of nickel and chromium, and the negative electrode wire 522 is made of a nickel alloy primarily composed of nickel and aluminum. The positive electrode wire 521 and the negative electrode wire 522 made of these alloys have extremely high heat resistance, so they can not only detect the presence or absence of a workpiece W even inside the chamber 10 at high temperatures of 100°C to 600°C, but also improve the durability of the detector 50.

(4) The heat treatment apparatus 1 of this embodiment includes a chamber 10 into which the workpiece W is loaded, a heater 40 provided inside the chamber 10 to heat-treat the workpiece W, and the aforementioned detector 50 provided inside the chamber 10 to detect the workpiece W by being pressed against it. Chromel and alumel have extremely high heat resistance, so they can detect the presence or absence of the workpiece W even inside the chamber 10 at high temperatures of 100°C to 600°C. Furthermore, when the positive electrode wire 521 is made of chromel and the negative electrode wire 522 is made of alumel, the heat treatment apparatus 1 of this embodiment reduces the pressure of the chamber 10 to create a vacuum for heat treatment. However, because chromel and alumel have high resistance to pressure changes, they can detect the presence or absence of the workpiece W even inside the chamber 10 under vacuum.

(5) The detector 50 of this embodiment may be installed at the back of the chamber 10. In this case, a large temperature difference can be ensured between the inside of the chamber 10, where heat does not easily escape, and the outside of the chamber 10, allowing the electrode portion 52 of the detector 50 to function reliably.

(6) In this embodiment, the workpiece W is rectangular, and a pair of detectors 50 are installed to abut the underside of diagonally opposite corners of the workpiece W. This allows the detector 50 to detect the workpiece W and further detect whether or not a crack has occurred at that corner. If a crack has occurred, any pieces of the workpiece W remaining inside the cassette 20 can be removed in advance, thereby preventing the pieces from colliding with the next workpiece W to be loaded. Furthermore, the solution L applied to the workpiece W and subjected to heat treatment can have a negative impact on the film quality if the temperature applied during the heat treatment varies from place to place. However, in this embodiment, the detector 50 is installed facing the area where no film is formed, and therefore the detector 50 can be prevented from removing heat from the area of the workpiece W where a film is formed.

[Modification]
(1) In the above embodiment, the positive electrode wire 521 is made of chromel and the negative electrode wire 522 is made of alumel, but this is not limited to this. For example, the positive electrode wire 521 may be made of iron and the negative electrode wire 522 may be made of an alloy mainly containing copper and nickel. Alternatively, both the positive electrode wire 521 and the negative electrode wire 522 may be made of a platinum-rhodium alloy, or both the positive electrode wire 521 and the negative electrode wire 522 may be made of a tungsten-rhenium alloy containing rhenium. Any other metal may be used as long as it generates an electromotive force due to the temperature difference between the point where the positive electrode wire and the negative electrode wire contact each other and the reference junction and can withstand the temperature inside the chamber 10 after heating.

(2) In the detector 50 of the above embodiment, the positive electrode wire 521 and the negative electrode wire 522 are in contact with each other via the conductive portion 541, but this is not limited to this. For example, the positive electrode wire 521 and the negative electrode wire 522 may be arranged so that they overlap in a plan view, and the conductive portion 541 may be lowered from above to bring the positive electrode wire 521 and the negative electrode wire 522 into direct contact with each other, thereby establishing electrical continuity between the positive electrode wire 521 and the negative electrode wire 522. In this case, the conductive portion 541 does not need to be made of a conductive material.

(3) In the above embodiment, four detectors 50 may be provided so as to abut against the underside of the four corners of the workpiece W, as shown in FIG. 13, for example. Hereinafter, the detector 50 provided so as to abut against the underside of the lower left corner of the workpiece W will be referred to as detector 50c, and the detector 50 provided so as to abut against the underside of the upper right corner of the workpiece W will be referred to as detector 50d. If all of the detectors 50a to 50d detect the workpiece W, it can be determined that "a workpiece is present." If at least one of the detectors 50a to 50d detects the workpiece W and at least one of the other detectors 50a to 50d does not detect the workpiece W, it can be determined that "a workpiece is present" and "a workpiece is cracked." If none of the detectors 50a to 50d detect the workpiece W, it can be determined that "a workpiece is not present." This makes it possible to more accurately detect the presence or absence of a workpiece W and any cracks in the workpiece W compared to when a pair of detectors 50 are provided so as to abut against the underside of diagonally opposite corners of the workpiece W.

(4) The detectors 50 in the above embodiment may be provided with a three-point support portion T near each detector 50, as shown in FIG. 14, for example. The three-point support portion T is provided, for example, on the beam 211. The three-point support portion T is composed of, for example, a set of three rods. The tips of these rods may be hemispherical, similar to the workpiece support portion 23. By providing this three-point support portion T, even if the workpiece W breaks during heat treatment, the fragments of the workpiece W are supported by the three-point support portion T. Therefore, the fragments of the workpiece W do not fall from the detector 50 and continue to be detected by the detector 50. In the above embodiment, for example, if all corners of the workpiece W that the detector 50 is abutting are broken, there is a risk that the detector 50 may determine that "no workpiece" is present even though the workpiece W remains. However, this embodiment reduces the risk of such an erroneous determination. This prevents the workpiece W remaining in the chamber 10 from colliding with the newly loaded workpiece W, causing it to break or chip.

Note that while four three-point support parts T are provided corresponding to four detectors 50 in Figure 14, this is not limiting. For example, if a pair of detectors 50 is provided as shown in Figure 8, a pair of three-point support parts T may be provided corresponding to the pair. That is, a three-point support part T may be provided near each detector 50. Also, instead of providing a three-point support part T near each detector 50, the detector 50 itself may be one of the rod-shaped bodies that make up the three-point support part T. In other words, a three-point support part T may be made up of one detector 50 and two rod-shaped bodies.

(5) In the above embodiment, the detector 50 is illustrated as detecting the presence or absence of a workpiece W between successive heat treatments. However, it is also possible to preheat the chamber 10 before the first heat treatment and detect the workpiece W from the time the workpiece W is loaded during treatment. By detecting the workpiece W not only between treatments but also when the workpiece W is loaded and during treatment, it becomes possible to monitor the workpiece W at this timing, and to detect whether the workpiece W was loaded without any problems, whether cracks have occurred in the workpiece W, and when the cracks occurred.

(6) Furthermore, in the above embodiment, the detection signal from the detector 50 is sent to a control device that controls the robot arm, and the robot arm is controlled. However, this is not limited to this. Based on the detection signal from the detector 50, the signal may be output to an output means such as a display device that is visible to the operator. For example, the fact that the workpiece W has been detected may be indicated on a panel or by turning on a lamp.

(7) Furthermore, in the above embodiment, the positive electrode wire 521 and the negative electrode wire 522 of the detector 50 are made of different metals, but this is not limited thereto and they may be made of the same metal. In this case, a separate power source for supplying electricity must be provided.

Other Embodiments
Although the embodiments of the present invention and modifications of each part have been described above, these embodiments and modifications of each part are presented as examples and are not intended to limit the scope of the invention. These novel embodiments described above can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and modifications are included within the scope and spirit of the invention, and are also included in the invention described in the claims.

1 Heat treatment apparatus 10 Chamber 11 Exhaust section 12 Exhaust pipe 121 Valve 20 Cassette 21 Cassette frame 211 Beam 22 Heat equalizing plate 23 Work support section 24 Cassette support section 30 Support section 31 Frame 32 Receiving section 40 Heater 50 Detector 51 Insulator 52 Electrode section 521 Positive electrode wire 522 Negative electrode wire 53 Holder 531 Holding section 532 Flange section 54 Detecting section 541 Conductive section 542 Protective section 55 Cap 80 Control section 81 Exhaust control section 82 Heating control section 83 Gas control section 84 Opening/closing control section 85 Memory section 86 Input/output control section 91 Input device 92 Output device A Opening section B Spring D Opening/closing door F Groove G Gas release section L Solution S Substrate W Work

Claims (8)

A detector that is provided inside a chamber in which a workpiece is heat-treated and detects the workpiece being carried into the chamber,
a positive electrode wire made of metal;
a negative electrode wire provided at a distance from the positive electrode wire and containing a metal different from that of the positive electrode wire;
a detection unit that is pressed against the workpiece to electrically connect one end of the positive electrode wire and one end of the negative electrode wire;
The other end of the positive electrode wire and the other end of the negative electrode wire are provided outside the chamber. The detection unit
a conductive part provided at a distance from the positive electrode wire and the negative electrode wire and made of the same metal as one of the positive electrode wire and the negative electrode wire;
When pressed against the workpiece, one end of the positive electrode wire and one end of the negative electrode wire are electrically connected via the conductive portion.
The detector of claim 1 . the positive electrode wire is made of a nickel alloy containing nickel and chromium as main components,
The negative electrode wire is made of a nickel alloy containing nickel and aluminum as main components.
3. A detector according to claim 1 or 2. a chamber into which the workpiece is carried;
a heater provided inside the chamber for heat-treating the workpiece;
a detector according to any one of claims 1 to 3, which is provided inside the chamber and detects the workpiece;
A heat treatment device comprising: The detector is provided at the back side of the chamber, away from an opening through which the workpiece is carried in and out.
The heat treatment apparatus according to claim 4 . The workpiece is rectangular,
The detectors are provided in pairs so as to abut on the undersides of diagonally opposite corners of the workpiece.
The heat treatment apparatus according to claim 4 . The workpiece is rectangular,
The detector is provided in four numbers so as to abut on the undersides of the four corners of the workpiece.
The heat treatment apparatus according to claim 4 . A three-point support unit is provided near each detector to support the underside of the corner of the workpiece.
The heat treatment device according to claim 6 or 7.