JP2009038230A - Light radiation type heat treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light radiation type heat treatment apparatus for executing heat treatment under the uniform temperature distribution of a treatment object in the high-speed heat treatment in which the heat treatment temperature is set to a comparatively lower value. <P>SOLUTION: The light radiation type heat treatment apparatus executes heat treatment including the up-temperature heat treatment for quickly increasing temperature of a treatment object up to the predetermined heat treatment temperature by radiation of light from a filament lamp arranged within a chamber to constitute a surface light source and the constant temperature heat treatment for heating the treatment object under the condition that the heat treatment temperature is maintained by driving the filament lamp by inputting a driving electrical power lower than that of the filament lamp in the up-temperature heat treatment. Within the chamber, a light absorber is arranged to absorb the light having the wavelength which is principally transmitted through the treatment object. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light irradiation type heat treatment apparatus that heats a target object by irradiating light from a filament lamp, for example, and in particular, light irradiation type heating for rapid heat treatment of a semiconductor substrate at a relatively low heat treatment temperature. The present invention relates to a processing apparatus.

At present, when various processes such as silicon oxide film formation (film formation) and impurity diffusion are performed in a semiconductor manufacturing process, heating to heat an object to be processed at a high temperature of, for example, 900 to 1200 ° C. by light irradiation from a light source. In particular, rapid thermal processing (hereinafter also referred to as “RTP (Rapid Thermal Processing)”) that rapidly raises or lowers the temperature of an object to be processed such as a semiconductor wafer, for example, is referred to as yield or yield. Since quality can be improved, it is preferably used.
In such a light irradiation type heat treatment apparatus that performs RTP, for example, a filament lamp in which a filament made of tungsten is disposed inside an arc tube is used as a heat source.

  In recent years, for example, in the process of forming a NiSi (nickel silicide) film, a PdSi (palladium silicide) film, and the like used for a gate electrode of a semiconductor element for the purpose of lowering the operating voltage (threshold voltage) of a MOS transistor. Therefore, it is necessary to heat-treat the semiconductor substrate as the object to be processed at a temperature lower than the processes such as the silicon oxide film formation and impurity diffusion, for example, a temperature of about 100 to 500 ° C.

Conventionally, as a method for forming a metal silicide film, for example, after a metal such as Ni or Pd is formed on the surface of a Si (silicon) substrate by a sputtering method, the Si substrate is heated using an electric furnace. In general, a method of generating a metal silicide compound by reacting Si with a metal is generally used.
However, when the heat treatment is performed using an electric furnace when forming the metal silicide film, the Si substrate is exposed to a high temperature for a long time in the electric furnace. There is a problem that the semiconductor element may be damaged due to deterioration.

  As a means for avoiding damage to the semiconductor element due to the heat treatment as described above, it is conceivable to perform rapid thermal processing (RTP) on the Si substrate using a filament lamp as a heat source.

  In addition, when the temperature distribution on the surface of the object to be processed such as a Si substrate is not uniform, the obtained semiconductor element does not have the desired performance required. However, it is necessary to heat the Si substrate with a uniform temperature distribution without causing local variations.

  However, when the heat treatment was actually performed under the temperature condition that the surface temperature of the Si substrate was about 100 to 500 ° C. using a light irradiation type heat treatment apparatus equipped with a filament lamp, the temperature of the Si substrate was locally increased. It has been found that there is a problem in that heating cannot be performed so that the temperature distribution of the Si substrate becomes uniform, with variations such as formation of high and low portions. The reason is considered as follows.

In rapid heat treatment using a filament lamp, usually, a surface temperature of the object to be processed is heated to a desired heat treatment temperature within a short time of several seconds, and then the temperature of the object to be processed is A constant-temperature heat treatment is performed in which the object to be processed is heated for a predetermined time while being maintained at the heat treatment temperature (see FIG. 4A).
In such a rapid heat treatment, for example, when the object to be processed is a Si substrate having a diameter of 300 mm, the surface temperature of the Si substrate is rapidly increased at a rate of temperature rise of, for example, about 100 ° C./second in the temperature rise heat treatment. In order to achieve this, it is necessary to use a light irradiation type heat treatment apparatus configured such that a large electric power with a rated power of, for example, about 90 kW can be input, and a filament lamp provided in such a light irradiation type heat treatment apparatus When performing the constant temperature heat treatment, the filament lamp is driven to light with the amount of electric power applied to the filament lamp being suppressed to a low power of about 5 kW, for example, in order to maintain the surface temperature of the Si substrate at a desired temperature state. There is a need to.

  However, when performing constant temperature heat treatment, when the filament lamp of the light irradiation type heat treatment apparatus having a rated power of 90 kW is turned on with a low input power of about 5 kW, it is emitted from the filament lamp as shown in FIG. As the emitted light wavelength shifts to the long wavelength side and the radiation intensity on the long wavelength side increases, that is, as the input power decreases, the emitted wavelength emitted from the filament lamp tends to shift to the long wavelength side. It turned out to be. This is because, in a filament lamp of a light irradiation type heat treatment apparatus having a rated power of 90 kW, for example, the mass of the filament per unit length so that the filament is not blown even when a large power is applied. This is considered to be because the filament temperature is significantly lower than that during rated lighting when the input power is small because the surface area and the surface area are designed to be large.

On the other hand, it is known that the Si substrate has a light transmission characteristic as shown in FIG. 7A, that is, the transmittance tends to increase (absorbance decreases) as the wavelength increases. The same tendency is observed not only for Si but also for GaAs (FIG. 7B), Ge (FIG. 7C), and the like.
Therefore, the light emission wavelength is shifted to the long wavelength side, for example, 1.1 μm or more, as the filament temperature is lower than that at the time of rated lighting by being driven to drive with input power sufficiently lower than the rated power. Most of the light emitted from the filament lamp passes through the Si substrate without being absorbed by the Si substrate.

  As described above, in the rapid heat treatment of the Si substrate using the filament lamp, the filament lamp is turned on at a power sufficiently lower than the rated power and the constant temperature heat treatment is performed, so that the light emitted from the filament lamp is changed to Si. As shown in FIG. 8, the light of the long wavelength side is shifted to the long wavelength side that mainly transmits through the substrate. In the light irradiation type heat treatment apparatus in which the filament lamp 70 is accommodated, the long wavelength side light is Si to be processed W. Reflecting between the reflector 71 located on the opposite side of the filament lamp 70 with respect to the Si substrate and the inner surface of the chamber 75 in which the Si substrate is disposed while passing through the substrate in a partially absorbed state. As a result, the temperature of the Si substrate is locally increased or decreased, and the temperature distribution of the Si substrate is not uniform. Erareru. In addition, the code | symbol 72 in FIG. 8 is a window member.

  The present invention has been made based on the above circumstances, and heat treatment is performed so that the temperature distribution of an object to be processed is uniform in rapid heat treatment in which the heat treatment temperature is set to a relatively low temperature. An object of the present invention is to provide a light irradiation type heat treatment apparatus that can be used.

In the light irradiation type heat treatment apparatus of the present invention, a filament lamp is arranged inside a chamber so as to constitute a planar light source, and the object to be processed is heated to a predetermined heat treatment temperature by light irradiation from the filament lamp. A heating and heating process that rapidly increases, and a power lower than the driving power of the filament lamp in the heating and heating process is turned on to drive the filament lamp so that the heat treatment temperature is maintained while the heating temperature is maintained. A light irradiation type heat treatment apparatus for performing a heat treatment comprising a constant temperature heating step for heating a treatment body,
A light absorber that absorbs light having a wavelength that mainly passes through the object to be processed is disposed inside the chamber.

  In the light irradiation type heat treatment apparatus of the present invention, the light absorber is configured to be disposed on the peripheral side surface surrounding the periphery of the object to be processed and the inner surface located on the back side of the object to be processed with respect to the filament lamp in the chamber. It is preferable that

  In the light irradiation type heat treatment apparatus of the present invention, the chamber is preferably provided with a cooling means for cooling the light absorber.

In the light irradiation type heat treatment apparatus of the present invention, a filament lamp is arranged inside a chamber so as to constitute a planar light source, and the object to be processed is heated to a predetermined heat treatment temperature by light irradiation from the filament lamp. A heating and heating process that rapidly increases, and a power lower than the driving power of the filament lamp in the heating and heating process is turned on to drive the filament lamp so that the heat treatment temperature is maintained while the heating temperature is maintained. A light irradiation type heat treatment apparatus for performing a heat treatment comprising a constant temperature heating step for heating a treatment body,
The chamber is made of a material having a wavelength absorption characteristic that absorbs light having a wavelength mainly transmitted through the object to be processed.

  According to the light irradiation type heat treatment apparatus of the present invention, a light absorber that absorbs light having a wavelength mainly transmitted through the object to be processed is disposed inside the chamber, so that it can be compared with the input power in the temperature rising heat treatment. When a constant temperature heating treatment is performed on the workpiece by realizing a necessary heating state by supplying a sufficiently low power, the filament temperature decreases and the proportion absorbed by the workpiece is small and large. Even if the output ratio of light in the long wavelength region that is transmitted through the object to be processed without being absorbed is increased, the wavelength light that contributes to heating of the object to be processed by absorption of the light in the long wavelength region by the light absorber Therefore, it is possible to reliably prevent variation in the temperature distribution of the object to be processed due to repeated reflection of light in the long wavelength region in the chamber. Kill result, the desired temperature distribution and the temperature distribution on the workpiece, it is possible to control the state of the temperature distribution on the object to be processed becomes uniform, it is possible to reliably desired heat treatment.

FIG. 1 is a front sectional view schematically showing a configuration example of a light irradiation type heat treatment apparatus of the present invention, and FIG. 2 is an arrangement of filament lamps constituting a lamp unit in the light irradiation type heat treatment apparatus shown in FIG. It is a top view which shows an example with a to-be-processed object.
The light irradiation type heat treatment apparatus 30 has an internal space divided into upper and lower parts by a plate-like window member 32 made of, for example, quartz to form a lamp unit accommodation space S1 and a heat treatment space S2, for example, stainless steel or aluminum. A lamp unit 40 composed of a plurality of filament lamps 10 is disposed in the lamp unit housing space S1.
The inner surface of the upper chamber constituting member 31A that defines the lamp unit housing space S1 in the chamber 31 has a cross-sectional shape selected from, for example, a part of a circle, a part of an ellipse, a part of a parabola, or a flat plate shape. A reflection surface is formed so that the upper chamber constituent member 31A functions as a reflector, so that light emitted from each filament lamp 10 of the lamp unit 40 can be directly or upper chamber constituent. The object to be processed W reflected by the inner surface of the member 31A and placed in the heat treatment space S2 is irradiated through the quartz window 32.

  As shown in FIG. 2, in the lamp unit 40, for example, 31 filament lamps 10 are juxtaposed at a predetermined interval of 15 mm, for example, with the lamp central axes positioned on the same plane level. Thus, a planar light source is configured. Each filament lamp 10 includes an arc tube made of, for example, a glass material with sealing portions formed at both ends. For example, a halogen gas is sealed in an internal space of the arc tube, and, for example, a tungsten wire is filled A coiled filament 20 formed by being wound in a coil shape is disposed so as to extend along the tube axis of the arc tube.

  In the light irradiation type heat treatment apparatus 30, when the object to be processed W is heat-treated, the object to be processed W is divided into, for example, three zones Z1 to Z3, and the object to be processed W is divided into each zone Z1 to Z3. The filament lamps 10 are turned on so as to obtain a temperature distribution according to the physical characteristics of the filaments. In order to control the temperature distribution on the workpiece W, the filaments constituting the lamp unit 40 are controlled. The lamps 10 are grouped into a plurality of lamps corresponding to the zones Z1 to Z3 of the workpiece W, and are connected to separate power supply apparatuses for each group.

  Specifically, the 17 filament lamps 10 located in the center are grouped to form a first lamp group 1A corresponding to the zone Z1 of the workpiece W, and the first lamp group. Seven lamps arranged on both sides of 1A are grouped as a unit, and a second lamp group 1B and a third lamp group 1C corresponding to each of the zone Z2 and the zone Z3 of the workpiece W are configured. The lamp groups (1A to 1C) are electrically connected to separate power supply devices R1 to R3, respectively.

Each filament lamp 10 of the lamp unit 40 is supported by a pair of fixed bases 42A and 42B.
The fixed bases 42A and 42B are composed of a conductive base 43 made of a conductive member and a holding base 44 made of an insulating member such as ceramics. The holding base 44 is provided on the inner wall of the upper chamber constituting member 31A. The conductive base 43 is held.

The upper chamber constituent member 31A is provided with a pair of power supply ports 36A and 36B to which power supply lines from the power supply devices R1, R2, and R3 of the power supply unit 35 are connected. The number of sets of 36B is set according to the number of filament lamps 10 and the like.
The power supply port 36A is electrically connected to the conductive base 43 of one fixed base 42A. The conductive base 43 of this fixed base 42A is electrically connected to an external lead on one end side of the filament 20 in one filament lamp 10. Connected. The power supply port 36B is electrically connected to the conductive base 43 of the other fixed base 42B. The conductive base 43 of the fixed base 42B is electrically connected to an external lead on the other end side of the filament. ing.
With such a configuration, each filament lamp 10 in the lamp unit 40 can be supplied with power by the power supply devices R1, R2, and R3 in the power supply unit 35, and the irradiance on the object W to be processed. The distribution can be arbitrarily set with high accuracy.

In the light irradiation type heat treatment apparatus 30, a cooling mechanism for cooling each filament lamp 10 is provided during the heat treatment of the workpiece W.
Specifically, the cooling air from the cooling air unit 45 provided outside the chamber 31 enters the lamp unit accommodation space S1 through the outlet 46A of the cooling air supply nozzle 46 provided in the upper chamber constituent member 31A. When the cooling air is introduced and blown to each filament lamp 10 in the lamp unit 40, the arc tube in each filament lamp 10 is cooled, and thereafter, the cooling air heated to high temperature by heat exchange is formed in the chamber 31. The air is discharged from the cooling air discharge port 47 to the outside.
In such a cooling mechanism, since the sealed portion of each filament lamp 10 has lower heat resistance than other portions, the outlet 46A of the cooling air supply nozzle 46 faces the sealed portion of each filament lamp 10. It is desirable that the sealing portion of each filament lamp 10 be preferentially cooled.
In addition, the flow of the cooling air introduced into the lamp unit housing space S1 is set so that the filament lamps 10 are not heated by the cooling air that has been subjected to heat exchange and has reached a high temperature.

  Further, in this light irradiation type heating device 30, the outlet 46 </ b> A of the cooling air supply nozzle 46 is also formed at a position near the window member 32, and the window member 32 is cooled by the cooling air from the cooling air unit 45. It is supposed to be configured. Thereby, the to-be-processed object W of the to-be-processed object W by receiving the undesired heating effect | action by the heat ray secondary radiated | emitted from the window member 32 stored by the radiant heat from the to-be-processed object W to be heated. Temperature uniformity in the object to be processed W due to redundancy of temperature controllability (for example, overshoot such that the temperature of the object to be processed becomes higher than the set temperature) and temperature variation of the heat stored window member 32 itself. It is possible to reliably prevent the occurrence of problems such as a decrease or a decrease in the temperature decrease rate of the workpiece W.

On the other hand, in the heat treatment space S <b> 2 in the chamber 31, a treatment table 33 to which the workpiece W is fixed is provided.
For example, when the object to be processed W is a semiconductor wafer, the processing table 33 is made of a refractory metal material such as molybdenum, tungsten, or tantalum, a ceramic material such as silicon carbide (SiC), quartz, or silicon (Si). It is preferable that the ring-shaped annular member is formed of a guard ring structure in which a step portion for supporting the semiconductor wafer is formed on the inner peripheral portion of the circular opening. In the processing table 33 having such a configuration, the workpiece W is fitted into the circular opening and is arranged in a state of being supported from the lower surface by the stepped portion.
Since the processing table 33 itself is heated to a high temperature by light irradiation, the outer peripheral edge of the semiconductor wafer facing the substrate 33 is supplementarily radiated and heated, thereby causing heat radiation from the outer peripheral edge of the semiconductor wafer. The temperature drop at the peripheral edge of the semiconductor wafer is compensated.

A plurality of temperature measuring units 51, for example, thermocouples or radiation thermometers for monitoring the temperature distribution of the object to be processed W are provided on the back side of the object to be processed W installed on the processing table 33. It is provided in contact with or close to. Here, the number and arrangement positions of the temperature measuring units 51 are not particularly limited, and can be set according to the dimensions of the workpiece W.
Each temperature measurement unit 51 is connected to the thermometer 50 and transmits temperature information monitored at a predetermined timing (for example, 50 times per second) to the thermometer 50.

  The thermometer 50 calculates the temperature at the measurement point of each temperature measurement unit 51 based on the temperature information monitored by each temperature measurement unit 51, and performs main control of the calculated temperature information via the temperature control unit 52. It has a function of sending to the unit 55.

Based on the temperature information at each measurement point on the workpiece W obtained by the thermometer 50, the main control unit 55 causes the temperature on the workpiece W to be uniformly distributed at a predetermined temperature. It has a function of sending a command to the temperature controller 52.
Further, the main control unit 55 sends a command to the cooling air unit 45 when the filament lamp 10 is turned on in the lamp unit 40, and the cooling air unit 45, based on this command, emits the arc tube, the window member 32, and the reflector. Cooling air is supplied so that the upper chamber constituent member 31A functioning as

The temperature control unit 52 has a function of controlling the magnitude of power supplied from the power supply unit 35 to the filament 20 of each filament lamp 10 based on a command from the main control unit 55.
Further, for example, temperature information that is a target to be reached according to the type of the object to be processed W, the target process, and the like can be set in the temperature control unit 52 in advance.

As will be described later, the light irradiation type heat treatment apparatus 30 is continuously performed in a temperature raising and heating step for rapidly raising the temperature of the workpiece W to a target heat treatment temperature and the temperature raising and heating step. The rapid heat treatment comprising a constant temperature heating step of constant temperature heating the workpiece W for a predetermined time while maintaining the heat treatment temperature is performed at a target heat treatment temperature that is relatively low, for example, 100 to 500 ° C. In the constant temperature heating process, electric power lower than the electric power supplied to each filament lamp 10 in the heating and heating process is supplied to each filament lamp 10 and each is performed. The filament lamp 10 is turned on.
Specifically, for example, when the object to be processed W is a silicon wafer of φ300 mm, the temperature increase rate of the silicon wafer is set to 100 ° C./second, and the heat treatment temperature is set to 400 ° C. In the heating process, the entire lamp unit 40 requires about 90 kW of power (total power), while the constant temperature heating process requires a low power of about 5 kW. An example of the configuration of the filament lamp 10 constituting the unit 40 will be described. Each filament lamp 10 includes, for example, a filament 20 having a length of 40 cm, a rated power density of 75 W / cm, a rated power of 3 kW, and a rated voltage of 200 V. A filament having a color temperature of 3000K at the rated lighting is used. The rated power density is usually designed in consideration of a control margin with respect to the basic power.

Thus, in the light irradiation type heat treatment apparatus, the proportion of the light emitted from the filament lamp 10 that is radiated from the filament lamp 10 during the constant temperature heat treatment in the chamber 31 is small and most of the light is absorbed. The light absorber which absorbs the light of the wavelength which permeate | transmits the to-be-processed object W without being provided.
When the workpiece W is, for example, a silicon wafer (Si), the light absorber preferably has a wavelength absorption characteristic that absorbs 90% or more of light having a wavelength of 1.1 μm or more, for example. When the processing object W is GaAs, for example, it has a wavelength absorption characteristic that absorbs 90% or more of light having a wavelength of 0.8 μm or more, and when the object to be processed W is Ge, 1.8 μm or more of light. It is preferable.

In this embodiment, as shown in FIG. 3, a light absorber 60 made of, for example, a carbon plate, black glass or the like and formed into a bottomed cylindrical shape includes a lower chamber constituting member that defines a heat treatment space S2. It is mechanically fixed to the lower chamber constituting member 31B so as to cover the entire inner surface of 31B.
With such a configuration, it is possible to reliably emit light having a wavelength that passes through the workpiece W, including light emitted directly from the lamp unit 40 toward the side peripheral surface of the heat treatment space S2. Can be absorbed. In addition, when the to-be-processed object W is a silicon wafer of (phi) 300 mm, it is preferable that the outer diameter of the light absorber 60 is (phi) 340 mm, and the thickness of the light absorber 60 is 2-5 mm, for example.

Further, the chamber 31 includes a cooling unit for cooling the light absorber 60. That is, in the lower chamber constituent member 31B that defines the heat treatment space S2 in the chamber 31, a plurality of recesses 31C each extend in parallel with, for example, the tube axis of the filament lamp 10 on the outer surface of the bottom wall. The water cooling pipes 65 are embedded and fixed in the respective recesses 31C.
By flowing the cooling water to each water cooling pipe 65, the lower chamber constituting member 31B is cooled, and the lower chamber constituting member 31B is prevented from being in a high temperature state when the filament lamp 10 is turned on. Since the light absorber 60 can be cooled via the lower chamber constituting member 31B, it is possible to prevent the light absorber 60 from becoming excessively high temperature (overheated state).

Hereinafter, the operation (heat treatment method) of the light irradiation type heat treatment apparatus 30 will be described.
As described above, in this light irradiation type heat treatment apparatus 30, as shown in FIG. 4 (a), for example, the temperature T1 of the workpiece W is shortened to a target heat treatment temperature T2 for about a few seconds. After the temperature raising and heating process for rapidly increasing the time, a constant temperature heating process for heating the object W by maintaining the temperature of the object W at the heat treatment temperature T2 for a predetermined time (Δt) is performed. Done.

When the heat treatment of the workpiece W is performed, first, the temperature control unit 52 performs the heat treatment temperature T2 corresponding to the treatment to be performed on the workpiece W, that is, the temperature at the constant temperature heat treatment (reached temperature). ) Is set, and a predetermined count number counted by a counter built in the temperature control unit 52, that is, a constant temperature heating time Δt is set.
When the power supply start signal is transmitted from the temperature control unit 52 to the main control unit 55, the main control unit 55 transmits a power supply start signal to each of the power supply devices R1 to R3 via the temperature control unit 52. As shown in FIG. 4 (b), each filament lamp 10 is turned on by supplying power close to the power (rated power) controlled to an appropriate magnitude for each filament lamp 10.
When the heating and heating process is started by light irradiation from each filament lamp 10, the temperature control unit 52 relates to the preset heating process temperature T 2 and the actual surface temperature of the workpiece W acquired by the thermometer 50. When the temperature information is compared and determined, and it is confirmed that the measured temperature of the workpiece W is lower than the heat treatment temperature T2, the power supply to each filament lamp 10 is continued.
Further, in the process of increasing the temperature of the object to be processed W to the heat treatment temperature T2, the temperature control unit 52 monitors the temperature distribution state of the object to be processed W. That is, based on the temperature information of each zone Z1 to Z3 of the workpiece W detected by each thermometer 50 so that the temperature of each zone Z1 to Z3 divided into three of the workpiece W is uniform. The amount of power supplied for each of the lamp groups 1A to 1C is adjusted.
Therefore, as shown in FIG. 4B, control is performed so that the total power value is maintained within the control margin.

  Next, the temperature control unit 52 performs a comparison operation between the preset heat treatment temperature T2 and the temperature information related to the actual surface temperature (actually measured value) of the workpiece W detected by the thermometer 50. When it is confirmed that the temperature of the processing object W has reached the heat treatment temperature T2, the temperature control unit 52 transmits a power supply amount adjustment signal to the main control unit 55 so as to reduce the power supply amount to each filament lamp 10. The main control unit 55 transmits a power supply amount adjustment signal to the power supply devices R1 to R3 of the lamp groups 1A to 1C via the temperature control unit 52, and each filament lamp 10 is heated and heated. And a count start signal is transmitted to the counter in synchronization with the power supply amount adjustment signal. Against continuously performed constant temperature heat treatment in the Atsushi Nobori heat treatment.

In the constant temperature heat treatment, the temperature of each of the zones Z1 to Z3 divided into three of the object to be processed W so that the temperature distribution of the object to be processed W is uniform while being maintained at a constant heat treatment temperature T2. Is monitored.
That is, the temperature control unit 52 compares and determines the preset heat treatment temperature T2 and the temperature information related to the actual surface temperature of the workpiece W transmitted from the thermometer 50, and the measured temperature of the workpiece W is determined. When it is confirmed that the temperature is higher than the heat treatment temperature T <b> 2, a power supply amount reduction signal is transmitted to the main control unit 55 so as to reduce the power supply amount to each filament lamp 10. Thus, a power supply amount reduction signal is transmitted to the power supply devices R1 to R3, and the power supply amount to each filament lamp 10 is reduced.
On the other hand, when it is confirmed that the measured temperature of the workpiece W is lower than the heat treatment temperature T2, a power supply amount increase signal is transmitted to the main control unit 55 so as to increase the power supply amount to each filament lamp 10, The control unit 55 transmits a power supply amount increase signal to the power supply apparatuses R1 to R3 via the temperature control unit 52, and increases the power supply amount to each filament lamp 10.
By adjusting the amount of power supplied to the filament lamp 10 as described above, the temperature of the workpiece W is maintained at a constant heat treatment temperature T2.
In the process of keeping the temperature of the object to be processed W constant at the heat treatment temperature T2, the temperature is detected by each thermometer 50 so that the temperatures of the zones Z1 to Z3 divided into three parts of the object to be processed become uniform. Based on the temperature information of the zones Z1 to Z3 of the workpiece W, the amount of power supplied to each of the lamp groups 1A to 1C is adjusted.
Therefore, as shown in FIG. 4B, control is performed so that the total power value is maintained within a predetermined range in a state where the total power value is limited to low power.

  Each filament lamp 10 is confirmed by the temperature control unit 52 confirming that the count number counted by the counter matches the preset count number, that is, that a predetermined constant temperature heat treatment time Δt has elapsed. The power supply stop signal is transmitted to the main control unit 55 so that the power supply to the power supply is stopped, and the main control unit 55 transmits the power supply stop signal to the power supply devices R1 to R3 via the temperature control unit 52. Thus, power supply to each filament lamp 10 is stopped and each filament lamp 10 is turned off.

  Examples of the heat treatment conditions in the rapid heat treatment as described above include, for example, a heat treatment temperature (arrival temperature) T2 of 100 to 500 ° C., and a temperature increase rate of the workpiece W in the temperature increase heat treatment is 10 to 150. The constant temperature heat treatment time Δt is 1 to 600 seconds at ° C./second.

  As described above, when the object to be processed W is heated at a constant temperature, the filament lamp 10 is lit with power that is significantly smaller than the rated power (for example, 100 W input power for a filament lamp with a rated power of 1000 W). As a result, the color temperature of the filament 20 decreases and the ratio of the light output in the long wavelength region of 1.1 μm or more out of the light emitted from the filament lamp 10 increases (see FIG. 6), and the workpiece W is formed. For example, since the silicon wafer (Si) itself has a property of easily transmitting light having a wavelength of 1.1 μm or more when heated to a temperature of 100 to 500 ° C. (see FIG. 7), it is emitted from the filament lamp 10. The non-uniform temperature distribution on the silicon wafer due to multiple reflections of light transmitted through the silicon wafer. There is a risk of condition.

  However, the light absorber 60 having a specific wavelength absorption characteristic corresponding to the light transmission characteristic of the object to be processed W covers the entire inner surface of the lower chamber constituting member 31B defining the heat treatment space S2 inside the chamber 31. By being provided so as to cover, according to the light irradiation type heat treatment apparatus 30 having the above-described configuration, a necessary heating state is realized by applying sufficiently lower power than the input power in the heating and heating process. Thus, when the constant temperature heating process is performed on the object to be processed W, the temperature of the filament 20 is decreased and the proportion absorbed by the object to be processed W is small, and most of the light passes through the object to be processed W without being absorbed. Even if the output ratio of light in the long wavelength region is increased, only light having a wavelength that contributes to heating of the workpiece W can be effectively used because the light in the long wavelength region is absorbed by the light absorber 60. As a result, it is possible to reliably prevent the temperature distribution of the object to be processed W from being varied due to repeated reflection of light in the long wavelength region in the chamber 31. As a result, the temperature distribution on the object to be processed W Can be controlled to be in a desired temperature distribution state and a state in which the temperature distribution on the workpiece W is uniform, and the desired heat treatment can be performed reliably.

  The light irradiation type heat treatment apparatus of the present invention is extremely useful when performing a process that requires a rapid heat treatment set at a relatively low heat treatment temperature, for example, 100 to 500 ° C.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various change can be added.
For example, as long as the light in the long wavelength region that passes through the object to be processed is reliably prevented from being multiple-reflected in the chamber, it is not limited to the configuration according to the above embodiment. A plate-shaped absorber is provided only on the inner surface of the bottom wall of the chamber, or particles (materials) having the specific wavelength absorption characteristics described above are applied to the inner surface of the lower chamber constituent member to form a film. Such a film-shaped absorber can be formed by, for example, forming a black hard anodized film, applying a black ceramic paint, or It can be obtained by plating black Ni · P.
In addition, the chamber and the light absorber need not be configured separately, and the chamber itself may be configured of a material having a specific wavelength absorption characteristic, such as SiC or black quartz.

  Further, as shown in FIG. 5, the light absorber 60 formed in a bottomed cylindrical shape is not only the inner surface of the lower chamber constituting member 31B that defines the heat treatment space S2, but also the lamp unit accommodating space S1. It can be set as the structure provided in the inner surface of 31 A of upper side chamber structural members which define these. In this case, similarly to the lower chamber constituting member 31B in the chamber 31, each of the plurality of recesses 31C is parallel to, for example, the tube axis of the filament lamp 10 on the outer surface of the upper wall of the upper chamber constituting member 31A. The upper chamber constituent member 31A is in a high-temperature state when the filament lamp 10 is turned on by forming the water-cooled tubes 65 in the respective recesses 31C so as to extend to each other. And the light absorber 60 is cooled via the upper chamber constituent member 31A, so that the light absorber 60 is prevented from being excessively heated (overheated).

  Further, the number and arrangement method of the filament lamps constituting the lamp unit are not limited to those of the above-described embodiments, and can be appropriately changed according to the purpose. For example, the lower side of the lamp unit in the vertical direction or The second lamp unit may be provided in multiple stages on the upper side in the vertical direction so that the tube axis of each filament lamp is orthogonal to the tube axis of each filament lamp of the lamp unit.

It is front sectional drawing which shows roughly the example of 1 structure of the light irradiation type heat processing apparatus of this invention. It is a top view which shows the example of an arrangement | sequence of the filament lamp which comprises the lamp unit in the light irradiation type heat processing apparatus shown in FIG. 1 with a to-be-processed object. It is sectional drawing which shows roughly a cross section perpendicular | vertical with respect to the tube axis | shaft of a filament lamp in the light irradiation type heat processing apparatus shown in FIG. It is a figure for demonstrating the rapid thermal processing method performed in the light irradiation type heat processing apparatus of this invention, Comprising: (a) Temperature profile, (b) It is a figure which shows an example of control of the total input electric power to a filament lamp. . It is sectional drawing which shows schematically the cross section perpendicular | vertical with respect to the tube axis | shaft of a filament lamp in the other structural example of the light irradiation type heat processing apparatus of this invention. It is a graph which shows a radiation spectrum in case the total radiant energy (lamp power density) is made the same. It is a graph which shows the light transmission characteristic of Si (b), GaAs (b), and Ge (c). FIG. 3 is a front sectional view schematically showing a state in which a filament lamp is turned on with a low input power in a light irradiation type heat treatment apparatus equipped with a filament lamp.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Filament lamp 20 Filament 30 Light irradiation type heat processing apparatus 31 Chamber 31A Upper side chamber structural member 31B Lower side chamber structural member 31C Recess 32 Window member 33 Processing stand 35 Power supply part 36A, 36B Power supply port 40 Lamp unit 42A, 42B Fixed base 43 Conductive base 44 Holding base 45 Cooling air unit 46 Cooling air supply nozzle 46A Air outlet 47 Cooling air outlet 50 Thermometer 51 Temperature measuring part 52 Temperature control part 55 Main control part 60 Absorber 65 Water cooling pipe 70 Filament lamp 71 Reflector 72 Window member 75 Chamber S1 Lamp unit accommodation space S2 Heat treatment space R1 to R3 Power supply device W Object to be processed

Claims (4)

Inside the chamber, a filament lamp is arranged to form a planar light source, and a temperature raising heating step for rapidly raising the object to be treated to a predetermined heat treatment temperature by light irradiation from the filament lamp, The constant temperature heating step of heating the object to be processed while maintaining the heat treatment temperature by turning on the filament lamp by turning on the power lower than the driving power of the filament lamp in the temperature raising and heating step. A light irradiation type heat treatment apparatus for performing heat treatment,
A light irradiation type heat treatment apparatus, wherein a light absorber that absorbs light having a wavelength that mainly passes through the object to be processed is disposed inside the chamber.   2. The light according to claim 1, wherein the light absorber is disposed on a peripheral side surface surrounding the periphery of the object to be processed and an inner surface positioned on a back surface side of the object to be processed with respect to the filament lamp in the chamber. Irradiation heat treatment equipment.   The light irradiation heat treatment apparatus according to claim 2, wherein the chamber includes a cooling unit for cooling the light absorber. Inside the chamber, a filament lamp is arranged to form a planar light source, and a temperature raising heating step for rapidly raising the object to be treated to a predetermined heat treatment temperature by light irradiation from the filament lamp, The constant temperature heating step of heating the object to be processed while maintaining the heat treatment temperature by turning on the filament lamp by turning on the power lower than the driving power of the filament lamp in the temperature raising and heating step. A light irradiation type heat treatment apparatus for performing heat treatment,
The light irradiation type heat treatment apparatus, wherein the chamber is made of a material having a wavelength absorption characteristic that absorbs light having a wavelength mainly transmitted through the object to be processed.

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