JPH0552445B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a heat treatment technology, and is a technology that is effective when applied to a heating device and a heat reaction treatment device that involves a reaction.

In particular, a temperature measurement device that uses thermal radiation (radiation temperature measurement) is used to automatically measure the temperature of the heated object, and according to the results, the amount of heating energy is automatically controlled to perform heat treatment with high precision. related to a device for

[Background technology]

Conventionally, temperature measurement methods using radiation thermometers have been used as temperature measurement means in heat treatment equipment. Non-contact thermometers have been used to measure the temperature in steel melting furnaces in the high temperature range, and recently, they have been used to measure the temperature in plasma processing equipment in the medium temperature range. It is used in various ways such as measurement.

However, in temperature measurement using a radiation thermometer, the amount of thermal radiation energy from the heat-treated object varies depending on the material, surface condition, etc. of the heat-treated object, which is the temperature measurement object, and it is not possible to accurately measure temperature.

Furthermore, in order to accurately measure temperature, it is necessary to set an emissivity value, which is a temperature conversion correction amount, and perform correction according to the temperature measurement object.

Conventionally, the emissivity value to be set has been determined on a trial basis by an operator using other temperature measuring means such as thermo paint or a thermocouple, and then determined and set on the radiation thermometer. (The emissivity of objects at room temperature is also described, for example, on page 115 of the Electronic Materials published by the Industrial Research Institute on October 1, 1979.) In particular, the electronic materials supplementary volume published by the Industrial Research Institute on November 15, 1983. Semiconductor manufacturing heat treatment equipment (crystal growth treatment equipment, impurity diffusion treatment equipment, crystal annealing treatment equipment, passivation film generation treatment equipment, photoresist baking treatment equipment, etc.) as described from page 45 onwards can perform various heat treatments or reactions. When using a radiation thermometer as a means of measuring the temperature of a semiconductor crystal or semiconductor wafer (thin plate) during heat treatment in a thermal reaction processing device (accompanied by thermal reaction processing equipment), the physical properties and surface condition may change depending on the product, manufacturing process, and heat treatment temperature. Therefore, the emissivity value of the semiconductor crystal or semiconductor wafer, which is the temperature measurement object, changes.

For this reason, the inventor of the present invention has clarified that in order to perform highly accurate temperature measurement, a problem arises in that the optimum emissivity must be set depending on each state.

In other words, it has been found that it is difficult to measure the temperature of a semiconductor wafer or the like, which is a heat-treated object, with a radiation thermometer, control the amount of heating energy according to the result, and automatically control the temperature to a predetermined temperature with high precision.

Recently, high frequency heating sources, microwave heating sources, laser heating sources, electron beam heating sources, and the like have been frequently used as heating sources for semiconductor manufacturing heat treatment equipment.

In order to accurately control the heat treatment using these heat sources, it is necessary to measure the temperature of the heated object itself using a non-contact method such as a radiation thermometer, and then control the amount of heating energy based on the temperature measurement results. be.

It has been found that the above-mentioned problems pose major challenges in realizing this method.

[Purpose of the invention]

An object of the present invention is to provide a heat treatment device that involves heat treatment or reaction that heats any heatable object to a predetermined temperature with high precision.

The above objects and novel features of the present invention will become apparent from the description and drawings herein.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, as a means for measuring the temperature of a heat-treated object, the heat-treated object is irradiated with two different radiant energies, and the difference △E' between the radiant energies emitted from the heat-treated object at this time and the difference △ between the two different radiant energies are measured. The relationship between the optical correction coefficient k = △E'/△E, which is the ratio of be.

Based on the above-mentioned principle, two different types of radiant energy irradiated to the heat-treated object are measured, and at the same time, the radiant energy radiated from the heat-treated object is measured, and based on the values, arithmetic processing is performed and the radiation of the heat-treated object is measured. Calculate and find the temperature value at the same time as finding the rate.

The heat treatment apparatus is equipped with a radiation thermometer having a function of automatically performing the above-described process, and the temperature of the heat treatment object whose emissivity value gradually changes is measured with high precision.

The present invention realizes a heat treatment apparatus that controls the amount of heating energy supplied to a heat treatment object based on this highly accurately measured temperature measurement information, and performs heat treatment to a predetermined temperature with high accuracy.

Hereinafter, the content of the present invention will be specifically explained.

[Principle and configuration of radiation thermometer (temperature measurement means)]

FIG. 1 is a diagram explaining the principle of the present invention. In the figure, 1 is a radiation detector, 2 is a radiation source, 3 is a measurement object that is subjected to source processing, 4 is a wall surrounding the measurement object 3, and 5 is a radiation energy source of the radiation source 2 provided as necessary. Due to the blocking shutter, radiation detector 1
and the radiation source 2 are arranged in the direction of θ with respect to the normal N to the surface of the measuring object 3.

The temperature of the measurement object 3 is T, the emissivity is ε, the reflectance is ρ, the temperature of the radiation source 2 is Tr ₁ , Tr ₂ , the emissivity is ε _r ,
The temperature of wall 4 is Tw, and the output signal of radiation detector 1 is E.
(S), and the radiant energy of a blackbody at temperature T is E(T).

The detection outputs of the radiation detector 1 for two different radiant energies of the radiation source 2 are expressed as E(S ₁ ) and E(S ₂ ).
Then, the following formula holds true.

E(S ₁ )=εE(T)+αρε _r E(Tr ₁ ) +βρE(Tw) ……(1) E(S ₂ )=εE(T)+αρε _r E(Tr ₂ ) +βρE(Tw) ……( 2) Here, α is the rate at which the radiant energy emitted from the radiation source 2 reflects off the measurement object 3 and enters the radiation detector 1, and β is the rate at which the radiant energy from the wall 4 reflects off the measurement object 3 and is emitted. The rate of incidence on the detector 1 is α+β=1.

In other words, the first term on the right side of equations (1) and (2) is the radiant energy from the measuring object 3 itself, the second term is the radiant energy from the radiation source 2, and the third term is the contribution of the radiant energy from the wall 4. It is. Here, by subtracting equations (1) and (2), we get the following equation.

E(S ₁ )−E(S ₂ )=αρ{ε _r E(Tr ₁ ) −ε _r E(Tr ₂ )} αρ=E(S ₁ )−E(S ₂ )/ε _r E(Tr ₁ )−ε _r E(T
r ₂ )...(3) Also, when shutter 5 is opened and closed, equation (1) is used when it is open.
When closed, equation (2) becomes E(S ₂ ) = εE(T) + ρE (Tw) = εE(T) + αρE (Tw) + βρE (Tw) ...(4), and equation (3) becomes, αρ=ξE(S ₁ )−E(S ₂ )/ε _r E(Tr ₁ )−E(Tw
)...(5) becomes.

Here, let the left side of equations (3) and (5) be the optical correction coefficient k, which can be determined by measurement from the right side (ΔE'/ΔE).

Here, it has been found through experiments that the relationship between k=αρ and emissivity ε is a linear relational expression as shown in the following equation.

ε=A-Bk=A-B(αρ)...(6) To illustrate this relationship, as shown in Figure 2,
There are different straight lines depending on the type of object, such as a group of metal M ₁ and a croup of non-metal M ₂ . Coefficients A (A ₁ , A ₂ , ...), B (B ₁ , B ₂ , ...)
is determined in advance through experiments for each type of object to be measured.

Here, if we rewrite equation (1) or (2), E(T)=E(S ₁ )={αρε _r E(Tr ₁ )+βρE(Tw)
}/ε ...(7), and the value of ε obtained from equation (6), αρ obtained from equation (3),
By substituting the value obtained from βρ=ρ−αρ, the temperature T
is found.

Also, since ε+ρ=1, E(T)=E(S ₂ )−(1−ε)E(Tw)/ε ……(8) from equation (4), and this equation (8) By substituting the emissivity ε obtained from equation (6), the temperature T of the measuring object is found.

Note that in the above equation, if the temperature Tw of the wall 4 is sufficiently small, Tw can be omitted.

[Structure and principle of heating control device]

FIG. 3 shows the basic configuration of the heating control device of the present invention. To explain the configuration of the heating control device, the furnace wall 1
A heat-treated object 102 is placed inside the chamber. A predetermined amount of heating energy 106 is supplied to the heat-treated object 102 from a heating source 105 according to a heating source control output value 104 of a heating source control output section 103 .

On the other hand, the heat-treated object 102 is irradiated with radiant energy 110 from a radiation source 109 according to a radiation source control output value 108 of a radiation source control output unit 107 . At this time, radiation energy 111 from the heat-treated object 102 is detected by a radiation detector 112 .

The arithmetic processing unit 113 uses the type information 115 of the heated object 102, the radiation source radiant energy information 116, the detected radiant energy information 117, and the furnace wall temperature information 118 from the overall control unit 114 to perform the calculation based on the radiation thermometer principle described above. The heat treated product 102
The temperature value of the heat-treated object 102 is determined by automatically calculating the emissivity of the heated object 102 and transmitting it to the overall control unit 114 as measured temperature information 119.

The overall control unit 114 receives external inputs such as type setting information 120 and set temperature information 12 of the heating processing unit 102.
1 and two different radiant energy setting information 122 emitted from the radiation source 109 and transmits the information to the radiation source control output section 107 and the arithmetic processing section 113. Measured temperature information 119 and the heated object 102 simultaneously calculated by the calculation processing unit 113
The optimum output information 123 is provided to the heating source control output section 103 in order to control the heated object 102 to a predetermined temperature.

Next, the principle of the heating control device of the present invention will be explained.

When the heat-treated object 102 is determined, the heat-treated object 1
02, type setting information 120 such as the coefficients A and B described above sets setting temperature information 121 to be heated and at least two different radiant energy setting information 122 irradiated from the radiation source 109.

When the heating control device is started in this state, two different radiant energies 110 are generated from the radiation source 106.
is irradiated.

At the same time, at this time, radiant energy 1 corresponding to the above-mentioned E(S ₁ ) and E(S ₂ ) from the heat-treated object 102
11 is detected by a radiation detector 112.

In this way, the detection outputs E(S ₁ ) and E(S ₂ ) of the radiation detector 112, the temperature Tw of the furnace wall 101, the temperatures Tr ₁ and Tr ₂ of the radiation source 109, and the coefficients A and B according to the type.
Each piece of information is supplied to the calculation processing unit 113, and the following calculations are performed.

That is, the temperatures Tr ₁ and Tr ₂ of the radiation source 109 and the temperature Tw of the furnace wall 101 are E(Tr ₁ ), E(Tr ₂ ), E
(Tw) and considering the emissivity Er, the above
By performing calculations such as equations (3) and (5), the correction coefficient k=
Find αρ. Next, this correction coefficient k, coefficient A,
Calculate Equation (6) from B to find the emissivity ε.
Then, the temperature T is determined by calculating equations (7) and (8) from this emissivity ε.

The measured temperature information 119 and the set temperature information 121, which are the temperature T of the heated object 102 obtained in this way, are compared and calculated in the overall control section 114, and according to the result, the heating source from the heating source control output section 103 is The control output value 104 is controlled, and the heated object 102
precisely control the temperature to a predetermined temperature.

It is preferable that the type setting information of the heated object 102 is stored in advance in a storage means and read out according to the type.

Embodiment 1 FIG. 4 is a schematic diagram of a heating apparatus with a shutter auxiliary heat source function for heat-treating a semiconductor wafer according to an embodiment of the present invention.

To explain the device configuration, in the center of the furnace body 201 there is a stage 203 rotated by a motor 202.
A semiconductor wafer 204, which is an object to be heated, is set on this stage 203.

On the other hand, the furnace body 201 has a microwave generator 205.
A microwave 207 with an output set in a microwave output unit 206 is generated from the semiconductor wafer 2.
04 is heated.

A shutter is provided on the furnace body 201, and is opened and closed by a shutter drive section 209. Furthermore, Shyatsuta 2
There is a heater 210 above 08, and the temperature is controlled to a predetermined temperature by a heater output control section 211.

Further, the amount of radiant energy emitted from the semiconductor wafer 204 is measured by the radiation detector 212.

On the other hand, the arithmetic processing unit 213 processes the shutter temperature information 214 of the shutter 208, the heater temperature information 215 of the heater 210, the radiant energy information 216 from the semiconductor wafer 204, and the type information 218 of the semiconductor wafer 204 from the overall control unit 217. At the same time as determining the emissivity of 204, the temperature value is determined and provided to the overall control unit 217 as semiconductor wafer temperature information 219.

The overall control unit 217 takes in type information 218 of the semiconductor wafer 204 which is an external input, and provides the information to the arithmetic processing unit 213 . Further, the set temperature information 220 of the semiconductor wafer 204 and the arithmetic logic unit 21
Comparative calculations are performed using the semiconductor wafer temperature information 219 from 3, and optimum microwave output information 221 is provided to the microwave output section 206. Furthermore, according to the motor rotation speed setting information 222, the motor 202 is driven to control the rotation of the stage 203 at a predetermined rotation speed.
Further, the temperature of the heater 210 is kept constant via the heater output control section 211 based on the heater temperature setting information 203.

Next, a method of heating the semiconductor wafer 204 using this apparatus will be explained.

The semiconductor wafer 204 is set on the stage 203, and the semiconductor wafer type information 2 is sent to the overall control unit 217.
18. When the semiconductor wafer temperature setting information 220 and the motor rotation speed setting information 222 are set and started, the motor 202 is rotated at a predetermined rotation speed.

Next, a method of obtaining two different radiation sources by opening and closing the shutter will be explained. In other words, shutter 2
08 is opened, and the semiconductor wafer 204 is irradiated with radiant energy from the heater 210. At this time, radiant energy from the semiconductor wafer 204 is measured by a radiation detector 212 and sent to the arithmetic processing unit 213 as radiant energy information 216, and heater temperature information 215 is also taken in at the same time.

Next, close the shutter 208 and the shutter 2 at that time
The radiant energy from 08 is applied to the semiconductor wafer 204.
The radiation energy from the semiconductor wafer 204 at this time is measured in the same manner as described above and is taken into the arithmetic processing unit 213. However, the temperature of the furnace body 201 is kept constant.

From the relationship between the "difference in radiant energy detected from the semiconductor wafer 204" and the "difference between heater temperature and shutter temperature" in the above two different states,
The emissivity of the semiconductor wafer 204 is determined as explained in the radiation thermometer principle above. Furthermore, based on this determined emissivity, emissivity correction is automatically performed,
The temperature of the semiconductor wafer 204 is determined and transmitted to the overall control unit 217 as semiconductor wafer temperature information 219.

The overall control unit 217 compares the measured semiconductor wafer temperature information 219 with the set temperature information 220, and according to the comparison result, provides the optimum microwave output information 221 to the microwave output unit 206, and outputs the microwave. The corresponding output is supplied from the section 206 to the microwave generating section 205, and a microwave 207 with an optimum output is generated to generate the microwave 207 on the semiconductor wafer 20.
Heat 4.

In order to heat the semiconductor wafer 204 with high precision, closed loop control is performed to control the microwave output value according to the temperature measurement results described above, and the semiconductor wafer 204 is heated to a predetermined temperature with high precision.

Embodiment 2 FIG. 5 is a schematic diagram of a thermal device with a reflector function for heating a semi-transparent semiconductor wafer with radiant energy irradiated from an auxiliary heat source.

This example differs from Example 1 in the following three ways.
It is an item.

(1) An infrared light-emitting element is used as a radiation source that emits two different radiant energies.

(2) Placing a plate-shaped object on the back surface of the semiconductor wafer that reflects the radiant energy emitted from the auxiliary radiation source has the effect of turning the semiconductor wafer, which is a semitransparent object, into an apparently opaque object in response to the radiant energy emitted from the radiation source. is aiming for

(3) As a heating source, the metal plate is heated by eddy current resistance loss induced on the metal plate by an electromagnetic coil, and the heated metal plate is used as the heating source.

Based on the above premise, this embodiment will be briefly described.

An electromagnetic coil 302 and a metal plate 30 are placed inside the furnace body 301.
3, the metal plate 30
Gold plating 304 is applied to the third surface to efficiently reflect the radiant energy from the auxiliary radiation source. A semiconductor wafer 305 is set thereon, which is semitransparent to the radiant energy from the auxiliary radiation source.

Note that the heating temperature of the semiconductor wafer 305 can be adjusted by adjusting the power of the oscillation power supply 306.

To measure the temperature of the semiconductor wafer 305, the amount of infrared light emitted from the infrared light emitting element group 307a is measured by the light emitting power source 3.
07b to create two different radiant energy irradiation states that act on the semiconductor wafer 305, irradiate the semiconductor wafer 305, and emit energy amount information 308 at that time and information from the semiconductor wafer 305 detected by the radiation detector 309. Based on the amount of radiant energy 310, the arithmetic processing unit 311 performs the same processing as in the first embodiment to measure the temperature of the semiconductor wafer 305.

The wafer temperature information 312 and the set temperature information 313 described above are compared and processed by the front body control unit 314, and the oscillation power supply 306 is controlled so that the semiconductor wafer 305 can be heated to a predetermined temperature with high accuracy.

〔effect〕

(1) According to the present invention, when at least two different radiant energies are radiated from the radiation source to the heat-treated object, the difference in the radiant energy from the heat-treated object and the value regarding the two different radiant energies emitted by the radiation source. The optical correction coefficient, which is the ratio of the difference, and the emissivity value of the heat-treated object are a linear relational expression, and the coefficients of the linear relational expression are stored in the storage means, so temperature measurement is possible. The means are
The heat-treated object can be automatically measured by correcting the emissivity based on the linear relational expression stored in the storage means, and the temperature can be measured with high accuracy even when various heat-treated objects having different emissivities are supplied. Furthermore, since the control means can control the amount of heating energy based on the temperature measurement results, highly accurate heating processing can be performed.

(2) From item (1) above, highly accurate heat treatment can be achieved,
Synergistic effects such as improved processing quality, increased processing yield, and reduced processing costs can be obtained.

Although the invention has been specifically explained above based on the embodiments of the invention made by the present inventor, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the invention. Needless to say, it is.

For example, a laser beam, an electron beam, plasma heating, or the like can be used as a heating source, and not only heating but also a reaction treatment apparatus such as a thermal reaction treatment or a plasma reaction treatment can be used.

[Application field]

The above explanation has mainly been about the case where the invention made by the present inventor is applied to semiconductor manufacturing equipment, which is the background field of application.
The present invention is not limited thereto, and can be applied to industrial heating in various fields such as surface heating equipment, film cure-bake processing equipment, metallurgical industry, chemical industry, and the like.

In addition, in this specification, the description has focused on a heating device, but not only a heat treatment device but also a heat treatment device that involves a reaction, or a heat treatment device that involves a heating phenomenon such as a plasma reaction treatment, while maintaining a constant temperature by cooling etc.
The present invention is also effective for reaction treatment apparatuses that require reaction treatment. Particularly in the case of heat treatment accompanied by a reaction, the emissivity gradually changes as the reaction progresses, so the present invention is more effective than a treatment device that only uses heat.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of a radiation thermometer, and FIG. 2 is a diagram showing the relationship between the emissivity and correction coefficient of the radiation thermometer. Third
This figure is a basic configuration diagram of a heating control device, and FIG. 4 is a schematic diagram of a heating device having a radiation thermometer using a shutter auxiliary heat source according to the first embodiment. FIG. 5 is a schematic diagram of a heating device according to Example 2, which uses an infrared light emitting element group as a radiation source and at the same time has a radiation thermometer using a reflection plate. 1,112,212,309...radiation detector,
2,109,210... Radiation source, 3... Measurement object, 102... Heat treated object.

Claims (1)

[Claims] 1. A difference in radiant energy from a heat-treated object when at least two different radiant energies are radiated from a radiation source to a heat-treated object, and a difference in values regarding two different radiant energies emitted by the radiation source. a temperature measuring means for determining emissivity based on the fact that the optical correction coefficient, which is the ratio of The emissivity of the object to be treated and the optical correction coefficient are a linear relational expression, and at least one set of coefficients of the linear expression is stored for each type of the object to be heated,
A storage means for supplying the temperature measurement means to the temperature measurement means, and a control means for heating the heat treatment object to a predetermined temperature by controlling the heating energy supplied to the heat treatment object based on the temperature measurement result of the heat treatment object obtained by the temperature measurement means. A heat treatment device comprising: 2. Claim 1, characterized in that the radiation source has a shutter structure between the radiation source and the heat-treated object, and radiates two different radiant energies by opening and closing the shutter. The heat treatment apparatus described in Section 1. 3. A patent characterized in that the radiation source is an infrared light-emitting element that can control the radiant energy and the wavelength of the radiation, thereby controlling the wavelength band and emitting two different radiant energies. A heat treatment apparatus according to claim 1. 4. As a means for measuring the temperature of a heat-treated object that is translucent to the radiant energy wavelength emitted from the radiation source, a plate-like object that can reflect the radiant energy wavelength band is arranged on the back side of the heat-treated object. The heat treatment according to claim 1, wherein the temperature of the translucent heat-treated object is measured by reflecting the radiant energy that has passed through the heat-treated object so that the translucent heat-treated object appears to be an opaque heat-treated object. Device.