JP6093136B2 - Heat treatment method and heat treatment apparatus - Google Patents

Description

  The present invention relates to a heat treatment method and a heat treatment apparatus for heating an object to be processed by irradiating light to the object to be processed containing a resin as a base material or an adhesive.

  In the semiconductor device manufacturing process, impurity introduction is an indispensable step for forming a pn junction in a semiconductor wafer. Currently, impurities are generally introduced by ion implantation and subsequent annealing. The ion implantation method is a technique in which impurities (dopant) elements such as boron (B), arsenic (As), and phosphorus (P) are ionized and collided with a semiconductor wafer at a high acceleration voltage to physically perform impurity implantation. . The implanted impurities are activated by annealing.

  In recent years, with further progress in miniaturization of semiconductor devices, shallower junctions have been demanded, and a technique for activating while suppressing diffusion by heating impurities for a very short time by flash lamp annealing (FLA) has been attempted. ing. However, the flash lamp annealing has a problem that the irradiation time is extremely short and the flash light with high intensity is irradiated, so that the wafer is broken and it is difficult to obtain a uniform temperature distribution.

  Therefore, Patent Documents 1 and 2 disclose a technique in which a plate-like member having an adjusted transmittance is provided between a flash lamp and a wafer so that part or all of flash light emitted from the flash lamp is reduced. ing.

JP 2009-123807 A JP 2009-260061 A

  On the other hand, in recent years, thin and flexible electronic devices such as electronic paper have attracted attention. Even in the manufacturing process of such a flexible electronic device, it is essential to anneal the object to be processed in which a functional layer such as an electrode is laminated on the surface of a substrate such as a resin.

  Conventionally, it has been common to anneal an object to be processed using a resin as a base material in a relatively low temperature oven over several hours. Since the heat resistance of the resin is significantly lower than that of a silicon or glass substrate, the oven temperature has to be relatively low.

  However, depending on the types of flexible electronic devices that are rapidly deployed in recent years, the functional layer may need to be heated to a temperature higher than the heat resistant temperature limit of the resin. In addition, depending on the type of the functional layer, the desired characteristics may not be obtained unless the annealing time is shorter than the above-described heat treatment of the semiconductor wafer. Further, when annealing time takes several hours, there is a problem that productivity is inevitably lowered.

  In order to solve these problems, it is conceivable to apply the above-described flash lamp annealing also to an object to be processed based on a resin. In the case of flash lamp annealing, the annealing time is extremely short, and it is possible to selectively heat only the functional layer on the surface of the object to be processed.

  However, even if only the functional layer on the surface of the object to be processed is heated at the moment of irradiation with flash light, the underlying resin base material may be heated to a temperature higher than the heat-resistant temperature by heat transfer from the functional layer. In particular, in the case of a flexible device or the like, the thickness of the functional layer is often several tens to several hundreds of nanometers, and when the surface of the functional layer is heated by flash light irradiation, it easily conducts heat to the base material. As a result, the problem that the resin base material is damaged due to thermal damage cannot be completely solved.

  The present invention has been made in view of the above problems, and an object thereof is to provide a heat treatment method and a heat treatment apparatus that can heat and irradiate an object to be processed without damaging a resin contained in the object to be processed. And

To solve the above problems, a first aspect of the invention, in the heat treatment method of heating the object to be processed by irradiating light to the object to be processed comprising a resin below the surface layer, the object to be processed Includes a structure in which a base material is pasted with an adhesive of an epoxy resin, and a functional layer of metal nano-ink is laminated on an upper surface of the base material on a surface layer of the base material , The object to be processed is heated by irradiation with flash light at an irradiation time of 10 microseconds or more and 100 microseconds or less.

  According to a second aspect of the present invention, in the heat treatment method according to the first aspect of the present invention, the flash light is transmitted through a filter to irradiate the object to be processed.

  The invention of claim 3 is characterized in that, in the heat treatment method according to the invention of claim 2, a predetermined wavelength region is cut from the flash light by passing through the filter and irradiated to the object to be processed. To do.

  According to a fourth aspect of the present invention, in the heat treatment method according to the third aspect of the present invention, ultraviolet light having a wavelength of 400 nm or less is cut from the flash light.

  According to a fifth aspect of the present invention, in the heat treatment method according to any one of the first to fourth aspects, the object to be processed includes a resin base material.

The invention of claim 6 is epoxy in the heat treatment apparatus for heating the object to be processed by irradiating light to the object to be processed comprising a resin below the surface, the workpiece is a substrate A holding means for holding the object to be processed , wherein the surface layer of the object to be processed is laminated with a functional layer of metal nano-ink on the upper surface of the substrate ; A flash lamp for irradiating the surface layer of the object to be processed held by the flash light, and a light emission control means for controlling the light emission of the flash lamp so that the flash light irradiation time is 10 to 100 microseconds, It is characterized by providing.

According to a seventh aspect of the present invention, in the heat treatment apparatus according to the sixth aspect of the present invention, the apparatus further comprises a filter provided between the holding means and the flash lamp.

According to an eighth aspect of the present invention, in the heat treatment apparatus according to the seventh aspect of the present invention, the filter cuts a predetermined wavelength region from the flash light.

According to a ninth aspect of the present invention, in the heat treatment apparatus according to the eighth aspect of the invention, the filter cuts ultraviolet light having a wavelength of 400 nm or less from the flash light.

According to a tenth aspect of the present invention, in the heat treatment apparatus according to any of the sixth to ninth aspects, the object to be processed includes a resin base material.

According to the first to fifth aspects of the present invention, the surface of the object to be treated is irradiated with flash light at an irradiation time of 10 to 100 microseconds to heat the object to be treated. Heat conduction from the surface layer of the treatment object to the resin is minimized, and the treatment object can be irradiated and heated without damaging the resin contained in the treatment object.

  In particular, according to the invention of claim 3, since the predetermined wavelength region is cut from the flash light by passing through the filter and irradiated to the object to be processed, the resin is prevented from being damaged by the light in the wavelength region. The

Further, according to the inventions of claims 6 to 10 , in order to control the light emission of the flash lamp so that the irradiation time of the flash light is not less than 10 microseconds and not more than 100 microseconds, Heat conduction is suppressed to a minimum, and the object to be processed can be heated by light irradiation without damaging the resin contained in the object to be processed.

In particular, according to the invention of claim 8 , since the filter cuts a predetermined wavelength range from the flash light, the resin is prevented from being damaged by the light in the wavelength range.

It is a figure which shows the principal part structure of the heat processing apparatus which concerns on this invention. It is a figure which shows the drive circuit of a flash lamp. It is a flowchart which shows the process sequence of the to-be-processed object in the heat processing apparatus of FIG. It is sectional drawing which shows the structure of a to-be-processed object. It is a figure which shows the temperature change of the functional layer of a to-be-processed object. It is a figure explaining the light emission time control of a flash lamp. It is a figure which shows the radiation spectral distribution of the flash lamp of xenon. It is a figure which shows the other example of the structure of a to-be-processed object. It is a figure which shows the other example of the arrangement | sequence of a flash lamp.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a main configuration of a heat treatment apparatus 1 according to the present invention. The heat treatment apparatus 1 is an apparatus that heats an object to be processed 8 by irradiating the object 8 with a resin as a base material with light. The heat treatment apparatus 1 includes, as main elements, a chamber 10 that accommodates the object 8 to be processed, a holding plate 20 that holds the object 8 to be processed, a heating light source 70 that irradiates the object 8 with flash light, and an optical filter 60. And comprising. The heat treatment apparatus 1 also includes a control unit 3 that controls various operation mechanisms provided in the apparatus to advance the process. In FIG. 1 and the subsequent drawings, the size and number of each part are exaggerated or simplified as necessary for easy understanding.

  The chamber 10 is provided below the heating light source 70, and includes a chamber side wall 11 and a chamber bottom 12. The chamber bottom 12 covers the lower part of the chamber side wall 11. A space surrounded by the chamber side wall 11 and the chamber bottom 12 is defined as a heat treatment space 15. A chamber window 18 is attached to the upper opening of the chamber 10 to close it.

  The chamber window 18 constituting the ceiling portion of the chamber 10 is a plate-like member made of quartz, and functions as a quartz window that transmits the light irradiated from the heating light source 70 to the heat treatment space 15. The chamber side wall 11 and the chamber bottom 12 constituting the main body of the chamber 10 are formed of a metal material having excellent strength and heat resistance such as stainless steel, for example.

  Further, in order to maintain the airtightness of the heat treatment space 15, the chamber window 18 and the chamber side wall 11 are sealed by an O-ring (not shown). That is, an O-ring is sandwiched between the peripheral edge of the lower surface of the chamber window 18 and the chamber side wall 11 to prevent gas from flowing in and out from these gaps.

  A holding plate 20 is provided inside the chamber 10. The holding plate 20 is a flat plate member made of metal (for example, aluminum). The holding plate 20 places the workpiece 8 in the chamber 10 and holds it in a horizontal posture. In addition, the holding plate 20 includes a heater 21. The heater 21 is configured by a resistance heating wire such as a nichrome wire, and generates heat when receiving power supply from a power supply source (not shown) to heat the holding plate 20. In addition to the heater 21, the holding plate 20 may be provided with a cooling mechanism such as a water cooling tube.

  The holding plate 20 is provided with a temperature sensor (not shown) configured using a thermocouple. The temperature sensor measures the temperature near the upper surface of the holding plate 20, and the measurement result is transmitted to the control unit 3. The control unit 3 controls the output of the heater 21 based on the measurement result by the temperature sensor, and sets the holding plate 20 to a predetermined temperature. The workpiece 8 held on the holding plate 20 is heated to a predetermined temperature by the holding plate 20.

Further, the heat treatment apparatus 1 includes a gas supply mechanism 40 that supplies a treatment gas to the heat treatment space 15 in the chamber 10 and an exhaust mechanism 50 that exhausts the atmosphere from the heat treatment space 15. The gas supply mechanism 40 includes a processing gas supply source 41, a supply pipe 42 and a supply valve 43. The distal end side of the supply pipe 42 is connected to the heat treatment space 15 in the chamber 10, and the proximal end side is connected to the processing gas supply source 41. A supply valve 43 is provided in the course of the supply pipe 42. By opening the supply valve 43, the processing gas is supplied from the processing gas supply source 41 to the heat treatment space 15. The processing gas supply source 41 can supply an appropriate processing gas according to the type of the object to be processed 8 and the processing purpose. In the present embodiment, the processing gas supply source 41 supplies nitrogen gas (N ₂ ).

  The exhaust mechanism 50 includes an exhaust device 51, an exhaust pipe 52, and an exhaust valve 53. The distal end side of the exhaust pipe 52 is connected to the heat treatment space 15 in the chamber 10, and the proximal end side is connected to the exhaust device 51. An exhaust valve 53 is provided in the course of the exhaust pipe 52. As the exhaust device 51, an exhaust utility of a factory where the vacuum pump or the heat treatment device 1 is installed can be used. By opening the exhaust valve 53 while operating the exhaust device 51, the atmosphere of the heat treatment space 15 can be discharged out of the device. The atmosphere of the heat treatment space 15 can be adjusted by the gas supply mechanism 40 and the exhaust mechanism 50.

  The heating light source 70 is provided above the chamber 10. The heating light source 70 includes a plurality of flash lamps FL (11 for convenience of illustration in FIG. 1, but is not limited thereto), a reflector 72 provided so as to cover the entire upper part, It is configured with. The heating light source 70 irradiates flash light from the flash lamp FL through the optical filter 60 and the quartz chamber window 18 described later to the object 8 to be processed held by the holding plate 20 in the chamber 10. The plurality of flash lamps FL are rod-shaped lamps each having a long cylindrical shape, and are arranged in a plane so that their longitudinal directions are parallel to each other along the horizontal direction.

  FIG. 2 is a diagram showing a driving circuit for the flash lamp FL. As shown in the figure, a capacitor 93, a coil 94, a flash lamp FL, and an IGBT (insulated gate bipolar transistor) 96 are connected in series. As shown in FIG. 2, the control unit 3 includes a pulse generator 31 and a waveform setting unit 32 and is connected to an input unit 33. As the input unit 33, various known input devices such as a keyboard, a mouse, and a touch panel can be employed. The waveform setting unit 32 sets the waveform of the pulse signal based on the input content from the input unit 33, and the pulse generator 31 generates the pulse signal according to the waveform.

  In the present embodiment, a xenon flash lamp is used as the flash lamp FL. The flash lamp FL includes a rod-shaped glass tube (discharge tube) 92 in which xenon gas is sealed and an anode and a cathode are disposed at both ends thereof, and a trigger electrode provided on the outer peripheral surface of the glass tube 92. 91. A predetermined voltage is applied to the capacitor 93 by the power supply unit 95, and a charge corresponding to the applied voltage (charging voltage) is charged. A high voltage can be applied to the trigger electrode 91 from the trigger circuit 97. The timing at which the trigger circuit 97 applies a voltage to the trigger electrode 91 is controlled by the control unit 3.

  The IGBT 96 is a bipolar transistor in which a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is incorporated in a gate portion, and is a switching element suitable for handling high power. A pulse signal is applied from the pulse generator 31 of the control unit 3 to the gate of the IGBT 96. The IGBT 96 is turned on when a voltage higher than a predetermined value (High voltage) is applied to the gate of the IGBT 96, and the IGBT 96 is turned off when a voltage lower than the predetermined value (Low voltage) is applied. In this way, the drive circuit including the flash lamp FL is turned on / off by the IGBT 96. When the IGBT 96 is turned on / off, the connection between the flash lamp FL and the corresponding capacitor 93 is interrupted.

  Even if the IGBT 96 is turned on while the capacitor 93 is charged and a high voltage is applied to both end electrodes of the glass tube 92, the xenon gas is electrically an insulator, so that the glass is normal in the state. No electricity flows in the tube 92. However, when the trigger circuit 97 applies a high voltage to the trigger electrode 91 to break the insulation, an electric current instantaneously flows in the glass tube 92 due to the discharge between the both end electrodes, and excitation of the xenon atoms or molecules at that time Emits light.

  Further, the reflector 72 is provided above the plurality of flash lamps FL so as to cover all of them. The basic function of the reflector 72 is to reflect the flash light emitted from the plurality of flash lamps FL toward the heat treatment space 15.

  An optical filter 60 is disposed between the chamber window 18 of the chamber 10 and the heating light source 70. The optical filter 60 of the present embodiment is a plate-like optical member formed by dissolving a metal such as barium (Ba), arsenic (As), antimony (Sb), cadmium (Cd) in quartz glass. More specifically, at least one metal selected from the group consisting of barium, arsenic, antimony and cadmium is dissolved and contained in quartz glass. By including a metal component in quartz glass, light in a predetermined wavelength region is reflected or absorbed from light transmitted through the optical filter 60 and cut (shielded). The wavelength range to be cut depends on the type of metal dissolved in the quartz glass. The optical filter 60 of the present embodiment cuts ultraviolet light having a wavelength of 400 nm or less.

  By providing the optical filter 60 between the chamber 10 and the heating light source 70, when the flash light emitted from the flash lamp FL passes through the optical filter 60, ultraviolet light having a wavelength of 400 nm or less is cut. Then, the remaining flash light having a wavelength region of 400 nm or longer is transmitted through the optical filter 60 and irradiated onto the object to be processed 8 held on the holding plate 20.

  The control unit 3 controls the various operation mechanisms provided in the heat treatment apparatus 1. The configuration of the control unit 3 as hardware is the same as that of a general computer. That is, the control unit 3 stores a CPU that performs various arithmetic processes, a ROM that is a read-only memory that stores basic programs, a RAM that is a readable and writable memory that stores various information, control software, data, and the like. It is configured with a magnetic disk. The processing in the heat treatment apparatus 1 proceeds as the CPU of the control unit 3 executes a predetermined processing program. As shown in FIG. 2, the control unit 3 includes a pulse generator 31 and a waveform setting unit 32. As described above, the waveform setting unit 32 sets the waveform of the pulse signal based on the input content from the input unit 33, and the pulse generator 31 outputs the pulse signal to the gate of the IGBT 96 in accordance therewith.

  In addition to the above configuration, the heat treatment apparatus 1 is appropriately provided with various components. For example, the chamber side wall 11 is formed with a transfer opening for loading and unloading the workpiece 8. Further, in order to prevent an excessive temperature rise due to light irradiation from the flash lamp FL, a water cooling tube may be provided on the chamber side wall 11. Furthermore, in order to prevent heating of the optical filter 60 due to absorption of flash light, a mechanism for blowing cooling air to the optical filter 60 may be provided.

  Next, the process procedure of the to-be-processed object 8 in the heat processing apparatus 1 which has the said structure is demonstrated. FIG. 3 is a flowchart showing a processing procedure for the object 8 to be processed in the heat treatment apparatus 1. The processing procedure of the heat treatment apparatus 1 described below proceeds by the control unit 3 controlling each operation mechanism of the heat treatment apparatus 1.

  First, the workpiece 8 is carried into the chamber 10 (step S1). The workpiece 8 may be carried in by a transfer robot outside the heat treatment apparatus 1 or manually. FIG. 4 is a cross-sectional view showing the structure of the workpiece 8. The target object 8 of the present embodiment is configured by laminating a functional layer 82 on the upper surface of a resin base material 81. As the resin of the substrate 81, PEN (polyethylene naphthalate), PET (polyethylene terephthalate), or the like can be employed. The functional layer 82 is a layer of silver (Ag) nano-ink for electrode formation. As shown in FIG. 4, the workpiece 8 has a functional layer 82 formed on the surface layer, and includes a resin base material 81 below the surface layer.

  The workpiece 8 carried into the chamber 10 is placed and held on the upper surface of the holding plate 20 (step S2). The workpiece 8 is held by the holding plate 20 with the surface on which the functional layer 82 is formed facing the upper surface side. The upper surface of the holding plate 20 is heated in advance to a predetermined temperature by a built-in heater 21. The upper surface temperature of the holding plate 20 is controlled by the control unit 3. The object 8 is heated by heat conduction by being placed on the holding plate 20.

  Further, after the object to be processed 8 is carried into the chamber 10 and the heat treatment space 15 is closed, the atmosphere in the chamber 10 is adjusted (step S3). In the present embodiment, nitrogen gas is supplied from the gas supply mechanism 40 to the heat treatment space 15 in the chamber 10 and exhaust is performed by the exhaust mechanism 50. Thereby, an air flow of nitrogen gas is formed in the chamber 10, and the heat treatment space 15 is replaced with a nitrogen atmosphere.

  FIG. 5 is a diagram showing a temperature change of the functional layer 82 of the workpiece 8. The object 8 is carried into the chamber 10 at time t1, and the object 8 is held on the holding plate 20 at time t2. Thus, preheating (assist heating) of the object to be processed 8 by the holding plate 20 is started at time t2, and the temperature of the object to be processed 8 reaches a predetermined preheating temperature T1 at time t3. When the workpiece 8 is heated by the holding plate 20, the entire workpiece 8 including the resin base material 81 and the functional layer 82 is heated almost uniformly. Accordingly, in this preheating stage, both the base material 81 and the functional layer 82 are similarly heated to the preheating temperature T1. The preheating temperature T1 is appropriately set within a range that does not cause thermal damage to the resin base material 81 (about 120 ° C. or less for PEN and PET).

  Subsequently, after the temperature of the object 8 reaches the preheating temperature T1, the control unit 3 controls the flash lamp FL of the heating light source 70 toward the object 8 held on the holding plate 20 at time t4. Flash light is irradiated (step S4). When the flash lamp FL irradiates flash light, the electric power is accumulated in the capacitor 93 by the power supply unit 95 in advance. Then, in a state where charges are accumulated in the capacitor 93, a pulse signal is output from the pulse generator 31 of the control unit 3 to the IGBT 96 to drive the IGBT 96 on and off.

  The waveform of the pulse signal can be defined by inputting from the input unit 33 a recipe in which the pulse width time (on time) and the pulse interval time (off time) are sequentially set as parameters. In this embodiment, an on-time of 10 microseconds or more and 100 microseconds or less and an arbitrary off time thereafter are set, that is, a recipe in which one pulse having a width of 10 microseconds or more and 100 microseconds or less is set. Is input from the input unit 33. When such a recipe is input from the input unit 33 to the control unit 3, the waveform setting unit 32 of the control unit 3 sets a pulse waveform for one pulse having a width of 10 microseconds to 100 microseconds accordingly. Then, the pulse generator 31 outputs a pulse signal according to the pulse waveform set by the waveform setting unit 32. As a result, a pulse signal for one pulse having a width of 10 microseconds or more and 100 microseconds or less is applied to the gate of the IGBT 96, and the on / off driving of the IGBT 96 is controlled. Specifically, the IGBT 96 is turned on when the pulse signal input to the gate of the IGBT 96 is on, and the IGBT 96 is turned off when the pulse signal is off. In this embodiment, since a pulse signal for one pulse whose width is 10 to 100 microseconds is applied to the gate of the IGBT 96, the IGBT 96 is turned off after being turned on for 10 to 100 microseconds. It becomes a state.

  Further, in synchronization with the timing when the pulse signal output from the pulse generator 31 is turned on, the control unit 3 controls the trigger circuit 97 to apply a high voltage (trigger voltage) to the trigger electrode 91. A pulse signal is input to the gate of the IGBT 96 in a state where electric charges are accumulated in the capacitor 93 and a high voltage is applied to the trigger electrode 91 in synchronization with the timing when the pulse signal is turned on. When is turned on, a current flows between both end electrodes in the glass tube 92, and light is emitted by excitation of the xenon atoms or molecules at that time.

  In this manner, the control unit 3 outputs a pulse signal for one pulse having a width of 10 microseconds or more and 100 microseconds or less to the gate of the IGBT 96, and the trigger electrode 91 is synchronized with the timing when the pulse signal is turned on. When a high voltage is applied to the current, a current flows through the flash lamp FL, and flash light is emitted. When the pulse signal is turned off, the IGBT 96 is also turned off, the current flowing through the flash lamp FL is cut off, and the flash light emission is stopped. In this way, a current is passed through the flash lamp FL for an energization time of 10 microseconds or more and 100 microseconds or less, and the light emission time of the flash lamp FL is set to 10 microseconds or more and 100 microseconds or less.

  FIG. 6 is a diagram for explaining the light emission time control of the flash lamp FL. When the flash lamp FL is caused to emit light without using the IGBT 96, most of the electric charge accumulated in the capacitor 93 is consumed at one time, and the emission intensity waveform of the flash lamp FL is shown by the dotted line in FIG. It will be something. In this case, the light emission time of the flash lamp FL mainly depends on the inductance of the coil 94, but is approximately several milliseconds.

In the present embodiment, an IGBT 96 as a switching element is connected to a circuit including the flash lamp FL, and a pulse signal for one pulse having a width of 10 to 100 microseconds is output to the gate. Thereby, the supply of electric charge from the capacitor 93 to the flash lamp FL is intermittently performed by the IGBT 96, and the time during which the current flows through the flash lamp FL is controlled to be 10 microseconds or more and 100 microseconds or less. The flash lamp FL emits light only when a current flows between both end electrodes. That is, by the energization time of the flash lamp FL and 10 microseconds to 100 microseconds or less by IGBT 96, the waveform of the emission intensity of the flash lamp FL becomes one shown by the solid line in FIG. 6, also the emission time It is 10 microseconds or more and 100 microseconds or less.

  A part of the flash light emitted from the flash lamp FL directly goes to the holding plate 20 in the chamber 10, and the other part is once reflected by the reflector 72 and then goes into the chamber 10. At this time, the flash light emitted from the flash lamp FL passes through the optical filter 60 and then enters the heat treatment space 15. In the present embodiment, since the optical filter 60 that cuts ultraviolet light having a wavelength of 400 nm or less is installed between the heating light source 70 and the chamber window 18, the wavelength of 400 nm or less when the flash light passes through the optical filter 60. The ultraviolet light in the region is cut. As a result, flash light from which ultraviolet light having a wavelength of 400 nm or less is cut enters the heat treatment space 15 in the chamber 10. Then, the surface layer of the workpiece 8 held on the holding plate 20 is irradiated with flash light whose ultraviolet light is cut and whose irradiation time is 10 to 100 microseconds, and the function formed on the surface layer Layer 82 is heated.

  The temperature of the functional layer 82 irradiated with flash light from the flash lamp FL instantaneously increases to the processing temperature T2, and then rapidly decreases to the preheating temperature T1. A necessary heat treatment is performed on the functional layer 82 by such flash heating. If the functional layer 82 is silver nano-ink, the processing temperature T2 is about 180 ° C.

  Here, in this embodiment, the irradiation time of the flash lamp FL is set to an extremely short time of 10 to 100 microseconds. For this reason, only the functional layer 82 located on the surface layer side of the workpiece 8 is selectively heated and raised to the processing temperature T2. If the irradiation time of the flash light is an extremely short time of 10 microseconds or more and 100 microseconds or less, the heat conduction from the heated functional layer 82 to the base material 81 is suppressed to the minimum. Accordingly, only the functional layer 82 is heated up to the processing temperature T2, and the base material 81 is hardly heated from the preheating temperature T1. The processing temperature T2 (180 ° C.) of the present embodiment is a temperature exceeding the heat resistance temperature of the PEN or PET base material 81, but only the functional layer 82 is heated to the processing temperature T2 and the base material 81 is almost increased. Since it is not heated, it is prevented that the base material 81 having poor heat resistance is thermally damaged. On the other hand, since the functional layer 82 is heated to the necessary processing temperature T2, a desired heat treatment is surely performed. That is, if the workpiece 8 is heated by flash light irradiation with an irradiation time of 10 microseconds or more and 100 microseconds or less as in this embodiment, even if the substrate 81 has poor heat resistance, Without heating, the functional layer 82 can be heated to a target processing temperature T2 that exceeds the heat resistance temperature of the base material 81, and reliable heat treatment can be performed.

  In addition, the resin material constituting the substrate 81 is not only poor in heat resistance, but also easily deteriorates due to ultraviolet light. For example, PEN degrades with light in the wavelength range of 200 nm to 400 nm, and PET causes degradation with light in the wavelength range of 200 nm to 380 nm.

  FIG. 7 is a diagram showing a radiation spectral distribution of a xenon flash lamp FL. As shown in the figure, the flash light emitted from the xenon flash lamp FL contains many ultraviolet light components having a wavelength of 400 nm or less. Therefore, if the processing object 8 is irradiated with the flash light from the flash lamp FL as it is, the base material 81 absorbs the ultraviolet light component and is damaged.

  For this reason, in this embodiment, an optical filter 60 that cuts ultraviolet light having a wavelength of 400 nm or less is installed between the heating light source 70 and the chamber window 18, and the wavelength of 400 nm is obtained from the flash light irradiated on the surface of the workpiece 8. The following ultraviolet light is cut. Thereby, it can prevent that the base material 81 of the to-be-processed object 8 is damaged by the ultraviolet-light component contained in flash light. On the other hand, since the flash light irradiated on the surface of the object 8 includes light having a relatively longer wavelength than the wavelength of 400 nm, the necessary heat treatment for the functional layer 82 is surely executed. can do.

  After a predetermined time has elapsed after the flash heating process of the object 8 to be processed by flash light irradiation, the processed object 8 is unloaded from the chamber 10 (step S5). Thereby, a series of heat processing in the heat processing apparatus 1 is completed. Note that the chamber 10 may be replaced with an air atmosphere before the workpiece 8 is unloaded.

  In the present embodiment, flash heat treatment is performed by irradiating flash light from the flash lamp FL onto the workpiece 8 in which the functional layer 82 is laminated on the upper surface of the resin base material 81. At this time, the energization time to the flash lamp FL is set to 10 microseconds or more and 100 microseconds or less by the IGBT 96, whereby the flash light irradiation time is set to 10 microseconds or more and 100 microseconds or less.

  Since the flash light irradiation time is not less than 10 microseconds and not more than 100 microseconds, which is significantly shorter than the conventional (dotted line in FIG. 6), heat conduction from the heated functional layer 82 to the underlying resin base material 81 is minimized. It is suppressed. Therefore, it is possible to prevent the resin base material 81 from being damaged by heat conduction from the surface functional layer 82. On the other hand, since the functional layer 82 is heated to the necessary processing temperature T2, a desired heat treatment is surely performed. That is, in the present embodiment, the resin substrate 81 included in the object to be processed is damaged by irradiating the object 8 with flash light for an irradiation time of 10 microseconds or more and 100 microseconds or less. Instead, only the functional layer 82 can be heated to the required processing temperature T2 to perform a desired heat treatment.

  Conventionally, laser annealing is known as such a technique for performing light irradiation for an extremely short time. However, since laser annealing heats the object to be processed 8 by irradiating light with a line instead of a surface, processing unevenness may occur. Further, since heating is performed by irradiating light with a line, it takes a considerable time to process the entire surface of the object 8 to be processed.

  On the other hand, as in the present invention, if the irradiation time is flash light irradiation of 10 microseconds or more and 100 microseconds or less, the entire surface of the object to be processed 8 is irradiated at once, so that the processing that causes a problem in laser annealing is performed. Unevenness does not occur. Further, as compared with laser annealing, the time required for processing the entire surface of the object 8 is remarkably shortened (the time required for only a pure process is 10 microseconds or more and 100 microseconds or less). As a result, the processing time of the heat treatment apparatus 1 is also short. In other words, the technology according to the present invention has the advantages of laser annealing that performs light irradiation for a short time (suppression of heat conduction) and the advantages of flash lamp annealing that performs irradiation of light from the entire surface (reduction of processing time). Is.

  In this embodiment, an optical filter 60 that cuts ultraviolet light having a wavelength of 400 nm or less is installed between the holding plate 20 and the flash lamp FL to perform flash light irradiation. For this reason, when the flash light emitted from the flash lamp FL passes through the optical filter 60, ultraviolet light having a wavelength region of 400 nm or less is cut. Accordingly, ultraviolet light having a wavelength of 400 nm or less is cut from the flash light irradiated on the surface of the object 8 to be processed, and damage to the resin substrate 81 due to the ultraviolet light can be prevented. On the other hand, since the flash light irradiated to the surface of the object 8 includes light having a relatively strong wavelength longer than the wavelength of 400 nm, the functional layer of the object 8 to be processed is irradiated with the flash light. 82 can be raised to the required processing temperature T2.

  While the embodiments of the present invention have been described above, the present invention can be modified in various ways other than those described above without departing from the spirit of the present invention. For example, in the above-described embodiment, the target object 8 is formed by laminating the functional layer 82 of silver nanoink on the upper surface of the PEN or PET base material 81. However, the target object 8 is not limited to this. Various variations are possible.

  For example, in the above embodiment, the base material 81 of the object 8 is PEN or PET, but other resin materials such as polycarbonate and acrylic resin may be used instead. These resin materials also have poor heat resistance and are deteriorated by ultraviolet light. Both polycarbonate and acrylic resin are deteriorated by light in the wavelength range of 200 nm to 300 nm. When polycarbonate or acrylic resin is used as the substrate 81, the cut wavelength range of the optical filter 60 is set to 300 nm or less. The cut wavelength range of the optical filter 60 can be adjusted by changing the type of metal dissolved in the quartz glass. By providing the optical filter 60 for cutting ultraviolet light having a wavelength of 300 nm or less and setting the flash light irradiation time to 10 microseconds or more and 100 microseconds or less, the resin base material 81 is not damaged as in the above embodiment. The functional layer 82 can be heated to the required processing temperature T2 to perform the heat treatment.

  Further, the functional layer 82 laminated on the base material 81 is not limited to silver nano ink, and may be nano ink (or nano wire) of other metal such as copper. If the functional layer 82 is copper, the processing temperature T2 in the above embodiment is about 400 ° C. Further, the functional layer 82 may be amorphous silicon, doped polysilicon, ITO (indium tin oxide), gravure ink, or the like. When the functional layer 82 is made of ITO, the processing temperature T2 is about 220 ° C. If the functional layer 82 is silicon, the processing temperature T2 is 900 ° C. or higher.

  Further, the structure of the workpiece 8 may be as shown in FIG. The object 8 of FIG. 8 is configured by attaching a glass substrate 81 to the upper surface of a glass substrate 83 using an adhesive 84 and laminating a functional layer 82 on the upper surface of the substrate 81. As the adhesive 84, for example, an epoxy adhesive mainly composed of an epoxy resin can be used. The heat resistance temperature of the epoxy adhesive is about 160 ° C. By using the glass substrate 83 having a relatively high rigidity, the object 8 can be handled more easily than in the above-described embodiment in which the functional layer 82 is laminated on the resin base material 81. 8 also includes a resin adhesive 84 below the surface layer. After the necessary processing is completed, the base material 81 is peeled from the glass substrate 83, and the base material 81 on which the functional layer 82 is laminated is used as a device.

  The to-be-processed object 8 which has a structure like FIG. 8 is also flash-heated by the heat processing apparatus 1 similarly to the said embodiment. The glass substrate 83 and the glass substrate 81 have high heat resistance, and are not deteriorated by ultraviolet light. However, the resin adhesive 84 is poor in heat resistance and easily deteriorated by ultraviolet light, like the substrate 81 of the above embodiment. Therefore, similarly to the above embodiment, the flash light irradiation time is set to 10 microseconds or more and 100 microseconds or less, and ultraviolet light having a wavelength of 400 nm or less is cut from the flash light irradiated to the surface of the object 8 to be processed by the optical filter 60. By doing so, it is possible to increase the temperature of only the functional layer 82 to a required processing temperature and perform a desired heat treatment without damaging the resin adhesive 84 and causing thermal damage.

  In short, the object 8 to be processed by the heat treatment technique according to the present invention only needs to contain a resin below the surface layer. In the example of FIG. 4, the target object 8 includes a resin base material 81, and in the example of FIG. 8, the target object 8 includes a structure in which the base material 81 is pasted with a resin adhesive 84. By subjecting such an object to be processed 8 to heat treatment by the heat treatment technique according to the present invention, the object to be processed 8 can be irradiated and heated without damaging the resin contained in the object to be processed 8. .

  In the above embodiment, the energization time to the flash lamp FL is set to 10 microseconds or more and 100 microseconds or less by the IGBT 96. However, the present invention is not limited to this, and the flash light irradiation time is set to 10 microseconds by other methods. You may make it prescribe | regulate above 100 microseconds or less. For example, without providing the IGBT 96 in the circuit, the energization time to the flash lamp FL may be set to 10 microseconds or more and 100 microseconds or less by adjusting the inductance of the coil 94 and the capacitance of the capacitor 93. .

  In the above embodiment, the IGBT 96 is used as the switching element. However, instead of this, another transistor that can turn on and off the circuit in accordance with the signal level input to the gate may be used. However, since a considerable amount of power is consumed for the light emission of the flash lamp FL, it is preferable to employ an IGBT or a GTO (Gate Turn Off) thyristor suitable for handling high power as the switching element.

  In the above embodiment, quartz glass containing a predetermined metal component is used as the optical filter 60. However, the present invention is not limited to this, and light in a predetermined wavelength range can be cut from flash light. Anything is fine. For example, the optical filter 60 may be formed by enclosing water colored with a predetermined color ink in a hollow glass member. Alternatively, the optical filter 60 may be formed by forming a metal or metal oxide thin film on the surface of quartz glass. However, since such a thin film may be peeled off by a rapid temperature rise during flash light irradiation, it is preferable to dissolve a metal in quartz glass.

  Furthermore, the light of a predetermined wavelength range may be cut by making the configuration of the flash lamp FL itself different. Specifically, when the gas pressure of the xenon gas sealed in the glass tube of the flash lamp FL is lowered, the radiation spectral distribution in FIG. 7 is shifted to the long wavelength side. As a result, the ultraviolet light on the short wavelength side can be cut from the flash light itself emitted from the flash lamp FL. Conversely, when cutting long-wavelength infrared light from flash light, the gas pressure of the enclosed xenon gas may be increased. However, if the gas pressure of the xenon gas is changed, the intensity of the flash light may be reduced, or the flash lamp FL may be damaged. It is desirable to cut.

  Further, the wavelength range cut by the optical filter 60 is not limited to 400 nm or less, and may be an appropriate one according to the characteristics of the resin included in the object 8 to be processed. For example, as described above, if the resin included in the object to be processed 8 is polycarbonate or acrylic resin, the wavelength range cut by the optical filter 60 may be 300 nm or less. Moreover, if the resin contained in the to-be-processed object 8 is PEN, since it will deteriorate with the light of a wavelength range of 200 nm to 400 nm, the optical filter 60 that cuts only the light of the wavelength range of 200 nm to 400 nm is applied. Also good. Furthermore, when the resin contained in the object 8 has a property of being deteriorated by long-wavelength infrared light, an optical filter 60 that cuts infrared light may be used. That is, the wavelength range cut by the optical filter 60 may be any wavelength range that damages the resin included in the object 8 to be processed.

  Further, the optical filter 60 is not limited to the one that cuts a specific wavelength range, and may be one that reduces the amount of light over the entire wavelength range. As such an optical filter 60, for example, a quartz glass surface roughened into a rubbed glass shape can be used. If the resin contained in the object to be processed 8 has poor heat resistance but does not have the property of deteriorating with respect to a specific wavelength range, the optical filter 60 is used to irradiate the object to be processed 8. The intensity of the flash light to be applied can be reduced, and damage to the resin contained in the object 8 can be prevented more reliably.

  Further, the optical filter 60 is not necessarily an essential element as long as the resin contained in the object to be processed 8 does not have a property of deteriorating with respect to a specific wavelength range.

  Further, in the above embodiment, the holding plate 20 is provided with the heater 21 so that the workpiece 8 is preheated before the flash light irradiation. However, when the processing temperature T2 is relatively low, the flashing is performed. Since the functional layer 82 can be heated up to the processing temperature T2 only by light irradiation, the preheating by the heater 21 is not necessarily an essential element. However, by performing flash light irradiation after the object to be processed 8 is stably heated to the preheating temperature T1 by the holding plate 20, the temperature history among the different objects to be processed 8 can be made uniform. .

  Further, a cooling mechanism may be provided on the holding plate 20 to forcibly cool the workpiece 8 after the flash heat treatment.

  In the above embodiment, the reflector 72 is provided above the plurality of flash lamps FL. Instead, each of the plurality of flash lamps FL may be a lamp with a reflective film. That is, a reflective film is attached to the upper half of the glass tube of each flash lamp FL, thereby reflecting the flash light toward the heat treatment space 15. When such a flash lamp FL with a reflective film is used, as shown in FIG. 9, the flash lamps FL at both ends of the lamp array are located below the other flash lamps FL (on the side closer to the object 8). It may be arranged to increase the illuminance at the periphery of the object 8 to be processed. In this case, two or more flash lamps FL may be arranged close to the workpiece 8 at each end of the lamp array.

  In the above-described embodiment, the heating light source 70 is provided with the xenon flash lamp FL, but another rare gas flash lamp such as krypton may be used instead.

  The heat treatment method and the heat treatment apparatus according to the present invention can be applied to various objects to be treated including resin, and in particular, flexible devices, flexible displays, flat panel displays (FPD), electronic equipment, solar cells used for electronic paper and the like. It can be suitably used for batteries, fuel cells, semiconductor devices and the like.

DESCRIPTION OF SYMBOLS 1 Heat processing apparatus 3 Control part 8 To-be-processed object 10 Chamber 15 Heat processing space 18 Chamber window 20 Holding plate 21 Heater 31 Pulse generator 32 Waveform setting part 40 Gas supply mechanism 50 Exhaust mechanism 60 Optical filter 70 Heating light source 72 Reflector 81 Base material 82 Functional layer 83 Glass substrate 84 Adhesive 93 Capacitor 94 Coil 96 IGBT
FL flash lamp

Claims (10)

A heat treatment method for heating a target object by irradiating light to the target object including a resin below the surface layer,
The object to be treated includes a structure in which a base material is pasted with an epoxy resin adhesive,
In the surface layer of the object to be processed, a functional layer of metal nano ink is laminated on the upper surface of the base material,
A heat treatment method comprising heating the object to be processed by irradiating the surface layer of the object with flash light for an irradiation time of 10 microseconds or more and 100 microseconds or less. The heat treatment method according to claim 1,
A heat treatment method comprising irradiating the object to be processed with the flash light transmitted through a filter. The heat treatment method according to claim 2, wherein
A heat treatment method comprising irradiating the object to be processed by cutting a predetermined wavelength region from the flash light by transmitting the filter. In the heat processing method of Claim 3,
A heat treatment method, wherein ultraviolet light having a wavelength of 400 nm or less is cut from the flash light. In the heat treatment method according to any one of claims 1 to 4,
The said to-be-processed object contains the resin base material, The heat processing method characterized by the above-mentioned. A heat treatment apparatus for heating the object to be processed by irradiating light to the object to be processed containing resin below the surface layer,
The object to be treated includes a structure in which a base material is pasted with an epoxy resin adhesive,
In the surface layer of the object to be processed, a functional layer of metal nano ink is laminated on the upper surface of the base material,
Holding means for holding the object to be processed;
A flash lamp that irradiates a surface of the object to be processed held by the holding means with flash light;
Light emission control means for controlling the light emission of the flash lamp so that the irradiation time of the flash light is 10 microseconds or more and 100 microseconds or less;
A heat treatment apparatus comprising: The heat treatment apparatus according to claim 6 , wherein
A heat treatment apparatus, further comprising a filter provided between the holding means and the flash lamp. The heat treatment apparatus according to claim 7 , wherein
The heat treatment apparatus, wherein the filter cuts a predetermined wavelength region from the flash light. The heat treatment apparatus according to claim 8 , wherein
The heat treatment apparatus, wherein the filter cuts ultraviolet light having a wavelength of 400 nm or less from the flash light. In the heat treatment apparatus according to any one of claims 6 to 9 ,
The heat treatment apparatus, wherein the object to be processed includes a resin base material.

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