JP2000012479A - Heat treatment system for substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system in which the temperature of a substrate to be heat treated in a heat treatment furnace can be measured accurately and the substrate can be heated up to a desired temperature. SOLUTION: A light projecting section 26 for projecting temperature measuring laser light in parallel with the surface of a substrate W in a heat treatment furnace 10 and closely thereto is disposed on the periphery of the heat treatment furnace 10 and a light receiving section 28 is disposed oppositely thereto. Based on the intensity of laser light projected from the projecting section 26 and the intensity of laser light entering into the light receiving section 28, a light absorption data is obtained when the temperature measuring laser light passes through gas in the vicinity of the surface of the substrate W and then a substrate temperature operating section 40 determines the temperature of the substrate W by operating the gas temperature in the vicinity of the surface of the substrate W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for storing a substrate in a heat treatment furnace and supplying an active or inactive processing gas into the heat treatment furnace, such as a lamp annealing apparatus or a CVD apparatus. The present invention relates to a substrate heat treatment apparatus for performing heat treatment such as annealing, oxynitridation, and film formation on a substrate by heating the substrate by light irradiation or the like.

[0002]

2. Description of the Related Art In a substrate heat treatment apparatus of this type, for example, a lamp annealing apparatus, substrates are carried one by one through openings into a heat treatment furnace formed flat by quartz glass or the like, and the openings are closed. An active or inactive processing gas such as oxygen, nitrogen, argon, ammonia, or nitric oxide is supplied from the supply unit into the heat treatment furnace, and the substrate accommodated in the heat treatment furnace is heated by light irradiation from a lamp heater. Then, the substrate is heat-treated. In performing such heat treatment of a substrate, it is extremely important to accurately measure the surface temperature of the substrate in order to heat the substrate to a desired temperature.

Conventionally, as a method of measuring the temperature of a substrate housed in a heat treatment furnace, a temperature of the substrate is detected by bringing a thermocouple into direct contact with the substrate. In addition, a thermocouple is fixed to a measuring piece having the same thermal characteristics as the substrate, and the measuring piece is placed in a heat treatment furnace together with the substrate, and the temperature of the measuring piece is detected by the thermocouple. Thus, the temperature of the substrate is measured indirectly.

[0004]

However, in a system in which a thermocouple is directly brought into contact with a substrate housed in a heat treatment furnace to detect the temperature of the substrate, contact between the thermocouple and the substrate is caused by contact resistance. In many cases, the temperature of the substrate cannot be measured accurately because the contact resistance changes depending on the method. Moreover, since the thermocouple itself is also heated by the lamp heater, it has been more difficult to accurately measure the temperature of the substrate. Further, since the metal body comes into contact with the substrate, metal contamination may occur on the substrate, and the surface of the substrate may be damaged by the thermocouple.

In a method in which a measuring piece to which a thermocouple is fixed is provided in a heat treatment furnace and the temperature of the measuring piece is detected indirectly by detecting the temperature of the measuring piece by the thermocouple, the actual method is not used. Since the temperature of the substrate was not measured, the temperature of the substrate could not be measured accurately. Also,
Also in this method, since the thermocouple itself is heated by the lamp heater, it has been more difficult to accurately measure the temperature of the substrate. Furthermore, depending on the type of the substrate, the absorption characteristics such as infrared rays of the measuring piece are different from those of the substrate,
If the surface condition (emissivity, etc.) of the substrate changes due to film formation during the heat treatment, it has been more difficult to accurately measure the temperature of the substrate.

As described above, it is difficult to accurately measure the temperature of the substrate by the conventional substrate temperature measuring method. For this reason, the power supply to the lamp heater is controlled by the temperature controller based on the detection signal of the substrate temperature from the temperature measuring device, and even if the substrate is heated to a desired temperature, the temperature of the substrate is accurately adjusted. As a result, the heat treatment quality of the substrate was reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and it is possible to accurately measure the temperature of a substrate accommodated in a heat treatment furnace and to be heat-treated. It is possible to heat the substrate without causing metal contamination on the substrate or damaging the surface of the substrate, and furthermore, regardless of the type of the substrate or the change in the surface state of the substrate during the heat treatment process. It is an object of the present invention to provide a substrate heat treatment apparatus capable of accurately measuring the temperature of a substrate.

[0008]

Means for Solving the Problems Claims 1 and 2
According to the inventions described above, a heat treatment furnace for accommodating a substrate, gas supply means for supplying a treatment gas into the heat treatment furnace, a heating means for heating a substrate accommodated in the heat treatment furnace, and a heat treatment furnace Temperature measuring means for measuring the temperature of the substrate housed therein, and, based on the temperature of the substrate measured by the temperature measuring means, a temperature control means for controlling the heating means so that the substrate has a predetermined temperature. In the invention according to claim 1, the temperature measuring means is disposed on one side of a peripheral portion of the heat treatment furnace, and is close to a surface of a substrate housed in the heat treatment furnace. And a light projecting unit for projecting the laser beam for temperature measurement in parallel with the surface of the substrate, and disposed on the other side of the peripheral part of the heat treatment furnace so as to face the light projecting unit, and projected from the light projecting unit. Light receiving part where the temperature measuring laser beam Absorption of light when the laser beam for temperature measurement passes through a gas near the surface of the substrate, which is obtained from the intensity of the laser light projected from the light emitting part and the intensity of the laser light incident on the light receiving part. A measurement unit for measuring a gas temperature in the vicinity of the surface of the substrate from the data, wherein in the invention according to claim 2, the temperature measurement means is provided in a peripheral portion of the heat treatment furnace, and is provided in the heat treatment furnace. A light projecting unit for projecting the laser beam for temperature measurement close to the surface of the accommodated substrate and parallel to the surface of the substrate; and a light emitting unit arranged around the heat treatment furnace so as to be deviated from a position facing the light emitting unit. Is provided, the light receiving unit to which the laser beam for temperature measurement projected from the light projecting unit is incident, and is obtained from the intensity of the laser light projected from the light projecting unit and the intensity of the laser light incident on the light receiving unit, Laser beam for temperature measurement passes through gas near substrate surface From scattering data of the Kino light, respectively, characterized in that and a measuring unit for measuring the gas temperature in the vicinity of the surface of the substrate.

According to a third aspect of the present invention, in the substrate heat treatment apparatus according to the first or second aspect, the heating means includes a plurality of heating means provided in a direction parallel to the substrate housed in the heat treatment furnace. With a lamp heater, a plurality of radiation thermometers for measuring the temperature of a plurality of different points in the radial direction of the substrate housed in the heat treatment furnace,
A control signal output from the temperature control means to each of the plurality of lamp heaters is corrected based on a measurement result of each radiation thermometer.

[0010] In the substrate heat treatment apparatus according to the first aspect of the present invention, a laser beam for temperature measurement is projected from a light projecting portion provided on one side of a peripheral portion of the heat treatment furnace, and the projected laser beam is emitted. The light passes through the gas near the substrate in close proximity to and in parallel with the surface of the substrate in the heat treatment furnace, and is distributed on the other side of the periphery of the heat treatment furnace so as to face the light projecting portion. The light enters the installed light receiving unit. Then, in the measuring unit, the intensity of the laser beam projected from the light projecting unit and the intensity of the laser beam incident on the light receiving unit are determined based on the intensity of the laser beam for temperature measurement passing through the gas near the surface of the substrate. Is obtained, and the gas temperature near the surface of the substrate is measured from the light absorption data.

Further, in the substrate heat treatment apparatus according to the second aspect of the present invention, a laser beam for temperature measurement is projected from a light projecting portion provided in a peripheral portion of the heat treatment furnace, and the projected laser light is emitted from the heat treatment furnace. A light-receiving unit disposed close to the surface of the substrate inside and in parallel with the surface of the substrate, passing through the gas in the vicinity of the substrate, and being arranged at a periphery of the heat treatment furnace so as to deviate from a position facing the light-emitting unit. Incident on. Then, in the measuring unit, the intensity of the laser beam projected from the light projecting unit and the intensity of the laser beam incident on the light receiving unit are determined based on the intensity of the laser beam for temperature measurement passing through the gas near the surface of the substrate. Is obtained, and the gas temperature near the surface of the substrate is measured from the light scattering data.

As described above, in the substrate processing apparatus according to the first and second aspects of the present invention, the temperature of the substrate accommodated in the heat treatment furnace is measured by the temperature measuring means in a non-contact manner.
The temperature of the substrate is detected by directly contacting the thermocouple with the substrate, or the temperature of the measuring piece placed in the heat treatment furnace together with the substrate is measured indirectly to measure the temperature of the substrate. Therefore, the temperature of the substrate can be accurately measured. In addition, since the temperature of the substrate is measured by measuring the gas temperature near the surface of the substrate from the absorption or scattering data of the light when the laser beam for temperature measurement passes through the gas near the surface of the substrate, The means does not heat the components of the temperature measuring means themselves, which makes it possible to accurately measure the temperature of the substrate. Further, since the metal body is not brought into contact with the substrate, there is no risk of causing metal contamination on the substrate, and there is no fear that the surface of the substrate is damaged. Furthermore, even with respect to a plurality of types of substrates having different absorption characteristics such as infrared rays, even if the surface state (emissivity, etc.) of the substrate changes due to film formation in a heat treatment process, the gas temperature in the vicinity of the substrate surface is changed. Is measured, the temperature of the substrate can be accurately measured irrespective of the surface condition of the substrate. In this manner, since the temperature of the substrate in the heat treatment furnace can be accurately measured by the temperature measuring unit, the heating unit is controlled by the temperature control unit based on the substrate temperature detection signal from the temperature measuring unit. Thus, the substrate can be heated to a desired temperature.

[0013] In the substrate heat treatment apparatus according to the third aspect of the present invention, the plurality of radiation thermometers measure the temperature of a plurality of points in the radial direction of the substrate housed in the heat treatment furnace, and the temperature distribution over the entire surface of the substrate is measured. Is measured. Then, based on the measurement results of the respective radiation thermometers, a control signal output from the temperature control means to each of the plurality of lamp heaters arranged in a direction parallel to the substrate in the heat treatment furnace is output from the substrate surface. Is corrected so as to eliminate the temperature distribution described above, so that the temperature uniformity over the entire surface of the substrate is improved.

[0014]

Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing an example of an embodiment of the present invention and showing a schematic configuration of a lamp annealing apparatus which is a kind of a substrate heat treatment apparatus. The heat treatment furnace 10
Although not shown because it is formed in a flat shape with quartz glass or the like and provided in a direction perpendicular to the paper surface, it has an opening for loading and unloading the substrate W, and the opening is closed by closing the opening. And has a gas outlet. Inside the heat treatment furnace 10, a gas supply pipe 12 is provided.
And the gas outlet 14 at the tip thereof is arranged so as to face the center of the substrate W in the heat treatment furnace 10. The gas supply pipe 12 is connected to a gas supply path 16 provided with an electromagnetic on-off valve 18, a mass flow controller (not shown), and the like, and the gas supply path 16 is connected to a gas supply unit (not shown) for processing gas. It is connected to the.

The substrates W are supported one by one by the susceptor 20, are carried into the heat treatment furnace 10, are kept in a horizontal posture during the heat treatment, and are carried out of the heat treatment furnace 10. Outside the heat treatment furnace 10, a plurality of substrate heating lamp heaters 22 a, 22 b, and 22 c are provided near the upper wall surface of the heat treatment furnace 10.
Are provided in parallel with each other and in a direction parallel to the substrate W in the heat treatment furnace 10, and although not shown, a water-cooled reflector is provided on the back side (upper side) of the lamp heaters 22a, 22b, 22c. Have been.

A plurality of pyrometers (radiation thermometers) 24a, 24b, 24c are provided outside the heat treatment furnace 10. And the plurality of pyrometers 24
The temperature of the substrate W accommodated in the heat treatment furnace 10 and subjected to the heat treatment is measured at a plurality of different points in the radial direction of the substrate W by a, 24b, and 24c.

Further, in this lamp annealing apparatus, a light projecting part 26 is provided on one side of a peripheral part of the heat treatment furnace 10,
On the other side of the periphery of the heat treatment furnace, a light receiving unit 28 is provided so as to face the light emitting unit 26. One ends of optical fibers 30 and 32 are arranged and attached to the light projecting unit 26 and the light receiving unit 28, respectively.
The other ends of the light emitting devices 0 and 32 are inserted into the light emitting / receiving device unit 34. Although not shown, the light-emitting / light-receiving unit 34 includes a light-emitting element, for example, a semiconductor laser and a light-receiving element. In addition, the light receiving element of the light emitting / receiving device unit 34 and the light receiving unit 28 are connected to the optical fiber 32.
Is optically connected by Then, from the light projecting unit 26, for example, a single-wavelength laser beam L for temperature measurement is projected in a direction approaching the surface of the substrate W accommodated in the heat treatment furnace 10 and in parallel with the surface of the substrate W. The laser beam for temperature measurement projected from the light unit 26 passes through the gas near the surface of the substrate W and enters the light receiving unit 28. Further, as shown in the partially enlarged sectional view of FIG. 2 in the light projecting unit 26 and the light receiving unit 28 (FIG. ), A purge gas supply pipe 36 provided with an electromagnetic on-off valve 38 and the like.
Is communicated. Then, a purge gas, for example, a nitrogen gas is supplied from a purge gas supply unit (not shown) to the light projecting unit 26 and the light receiving unit 28 through the purge gas supply pipe 36, and the emission end face of the optical fiber 30 and the optical fiber 3
The film forming material is prevented from depositing on the incident end face 2 during annealing or the like.

The light emitting / receiving device 34 is connected to the substrate temperature calculating section 40. In the substrate temperature calculation unit 40, the laser beam for temperature measurement passes through the gas near the surface of the substrate W based on the intensity of the laser beam projected from the light projecting unit 26 and the intensity of the laser beam incident on the light receiving unit 28. Data on the absorption of light as it passes is determined. Since the gas absorbance is a function of temperature if the gas type and gas concentration are constant, the gas temperature near the surface of the substrate W is calculated from the light absorption data (absorbance), and the substrate W Is required. In order to calculate the gas temperature near the surface of the substrate W from the absorbance as described above, calibration curve data of the gas temperature and the absorbance at a predetermined concentration for a specific type of gas is created in advance, and the calibration curve is calculated. The data is stored in the memory of the substrate temperature calculator 40.

The substrate temperature calculating section 40 is connected to a temperature controller 42, and a detection signal of the temperature of the substrate W is sent from the substrate temperature calculating section 40 to the temperature controller 42. The temperature controller 42 is connected to a temperature distribution correction operation unit 44. The temperature distribution correction operation unit 44 includes a plurality of pyrometers 24a, 24b,
24c allows detection signals of temperatures measured at a plurality of different points in the radial direction of the substrate W in the heat treatment furnace 10 to be input.

In the lamp annealing apparatus having the above structure,
A laser beam for temperature measurement is projected from a light projecting unit 26 provided around the heat treatment furnace 10, and the projected laser light is applied to the surface of the substrate W which is housed in the heat treatment furnace 10 and is heat-treated. The light passes through the gas near the substrate W in parallel with the surface of the substrate W, and enters the light receiving unit 28 disposed around the heat treatment furnace 10 so as to face the light projecting unit 26. And
From the intensity of the projection laser light and the intensity of the incident laser light sent from the light emitting / receiving device unit 34 to the substrate temperature calculating unit 40, the substrate temperature calculating unit 40 outputs the temperature measuring laser light to the substrate as described above. Data on the absorption of light when passing through the gas near the surface is obtained, and the temperature of the gas near the surface of the substrate W is calculated from the data on the absorption of light, and
Is required. The detection signal of the temperature of the substrate W obtained by the substrate temperature calculating section 40 is transmitted to the temperature controller 4.
The correction signal based on the temperatures of the plurality of points on the substrate W detected by the plurality of pyrometers 24a, 24b, 24c is sent from the temperature distribution correction calculation unit 44 to the temperature controller 42. Then, the pyrometer 2 is sent from the temperature controller 42 to each of the lamp heaters 22a, 22b and 22c.
4a, a control signal corrected so as to eliminate the temperature distribution of the substrate W detected by the pyrometer 24b and the pyrometer 24c is output, and the lamp heater 2
The power supplied to 2a, 22b, 22c is adjusted separately.

As an example of a control algorithm in this apparatus, when the temperature of the substrate W obtained by the substrate temperature calculating section 40 is T, a PID control value P based on the temperature T is P = PID ( T). In addition, pyrometer 2
4a, T1, T2, and T3 at the respective points of the substrate W measured by the pyrometer 24b and the pyrometer 24c, respectively, the lamp heaters 22a, 22a and 22b are used to correct their temperature distribution.
b and P to be output to each of the lamp heaters 22c.
The ID control values P1, P2 and P3 are P1 = P + ΔP
1, P2 = P + ΔP2, P3 = P + ΔP3, where ΔP1 = PID (T−T1), ΔP2 = PI
D (T−T2), ΔP3 = PID (T−T3).

In the above-described embodiment, a plurality of pyrometers 24a, 24b and 24c are provided and supplied to the lamp heaters 22a, 22b and 22c so as to correct the temperature distribution of the substrate W detected by the pyrometers. However, when the substrate W has almost no temperature distribution, the pyrometers 24a, 24b, and 24c are not provided, and
The temperature controller 42 controls the lamp heaters 22a, 22a,
2b and 22c may be integrally controlled.

In the above embodiment, the light projecting section 26
The light receiving unit 28 is disposed so as to face the substrate W, and data for absorption of light when the temperature-measuring laser beam projected from the light projecting unit 26 passes through the gas near the surface of the substrate W is obtained. Although the temperature of the substrate W was measured from the absorption data of the above, the light-receiving unit was arranged so as to deviate from the position facing the light-emitting unit,
Obtain data of light scattering (Raman scattering) when the temperature-measuring laser light projected from the light projecting part passes through the gas near the surface of the substrate, and obtain the data of the vicinity of the substrate surface from the light scattering data. Can be measured.

[0025]

According to the first and second aspects of the present invention, it is possible to accurately measure the temperature of a substrate housed in a heat treatment furnace and subjected to a heat treatment. Thus, the substrate can be heated to the same temperature, and thus the heat treatment quality of the substrate can be improved. In addition, it does not cause metal contamination on the substrate or damages the surface of the substrate, and can accurately measure the temperature of the substrate regardless of the type of the substrate or the change in the surface state of the substrate during the heat treatment process. it can.

In the substrate heat treatment apparatus according to the third aspect of the present invention, the temperature distribution over the entire surface of the substrate is measured and a plurality of lamp heaters are controlled so as to eliminate the temperature distribution. Uniformity can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing an example of an embodiment of the present invention and showing a schematic configuration of a lamp annealing apparatus.

FIG. 2 is a partially enlarged cross-sectional view of a light projecting unit provided in a heat treatment furnace in the lamp annealing apparatus shown in FIG.

[Explanation of symbols]

 W substrate 10 heat treatment furnace 12 gas supply pipe 14 gas outlet 16 gas supply path 20 susceptor 22a, 22b, 22c lamp heater 24a, 24b, 24c pyrometer 26 light emitting part 28 light receiving part 30, 32 optical fiber 34 light emitting / receiving part 34 36 Purge gas supply pipe 40 Substrate temperature calculator 42 Temperature controller 44 Temperature distribution correction calculator

Claims (3)

[Claims] A heat treatment furnace for accommodating a substrate; a gas supply unit for supplying a treatment gas into the heat treatment furnace; a heating unit for heating a substrate accommodated in the heat treatment furnace; A temperature measuring means for measuring the temperature of the substrate, and a temperature control means for controlling the heating means such that the substrate has a predetermined temperature based on the temperature of the substrate measured by the temperature measuring means. A heat treatment apparatus, wherein the temperature measurement means is disposed on one side of a peripheral portion of the heat treatment furnace, and measures temperature in close proximity to and parallel to the surface of the substrate housed in the heat treatment furnace. A light projecting unit that projects a laser beam, and a light receiving unit that is disposed on the other side of the peripheral part of the heat treatment furnace so as to face the light projecting unit, and into which the laser beam for temperature measurement projected from the light projecting unit enters. And a laser projected from the light projecting unit From the data of light absorption when the temperature-measuring laser light passes through the gas near the surface of the substrate, which is obtained from the intensity of the laser light incident on the light-receiving portion, the gas near the surface of the substrate is obtained. A substrate heat treatment apparatus comprising: a measurement unit for measuring a temperature. 2. A heat treatment furnace for accommodating a substrate, a gas supply means for supplying a processing gas into the heat treatment furnace, a heating means for heating a substrate contained in the heat treatment furnace, and a heat treatment furnace contained in the heat treatment furnace. A temperature measuring means for measuring the temperature of the substrate, and a temperature control means for controlling the heating means such that the substrate has a predetermined temperature based on the temperature of the substrate measured by the temperature measuring means. A heat treatment apparatus, wherein the temperature measuring means is disposed in a peripheral part of the heat treatment furnace, and emits a laser beam for temperature measurement in parallel with and parallel to the surface of the substrate accommodated in the heat treatment furnace. A light-emitting unit for projecting, a light-receiving unit disposed in a peripheral part of the heat treatment furnace so as to be deviated from a position facing the light-emitting unit, and receiving a laser beam for temperature measurement projected from the light-emitting unit, Laser light projected from the light emitting part From the scattering data of light when the temperature-measuring laser light passes through the gas near the surface of the substrate, determined from the intensity and the intensity of the laser light incident on the light-receiving portion, the gas temperature near the surface of the substrate is obtained. A substrate heat treatment apparatus, comprising: 3. The heating means includes a plurality of lamp heaters provided in a direction parallel to a substrate housed in the heat treatment furnace, and a plurality of lamp heaters provided in a radial direction of the substrate housed in the heat treatment furnace. A plurality of radiation thermometers for measuring a plurality of different temperatures are installed, and a control signal output from the temperature control unit to each of the plurality of lamp heaters is corrected based on a measurement result of each radiation thermometer. The substrate heat treatment apparatus according to claim 1 or 2, wherein the heat treatment is performed.