JPH08148502A - Temperature and semiconductor production system - Google Patents

Abstract

PURPOSE: To control the temperature of a semiconductor substrate or a glass substrate uniformly and accurately by forming the forward end part of a temperature detecting part, also serving as a supporting pin, of semiconductor or glass substrate of a material having high thermal conductivity and the base part thereof of an inorganic material having thermal conductivity lower than that of the substrate. CONSTITUTION: A supporting pin 14 comprises an alumina cap 16 of 4mm diameter having flat top, and a base part 17 made of a quartz glass tube of 3.5mm diameter. The top of the base part 17 is constricted to provide a neck part 17a of 2.5mm diameter. A silicon carbide film 18 is formed in the form of a plurality of rings on the surface of the base part 17 made of a quartz glass tube. A thermocouple 15 is bonded, at the bonding part thereof, to the cap 16 through an inorganic adhesive. This structure realizes accurate measurement of temperature of semiconductor or glass substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus, particularly a semiconductor manufacturing apparatus using a heat source such as an infrared lamp or a ceramic heater (for example, an annealing apparatus, a chemical vapor deposition (C
VD) device, asher, or device for forming a large number of semiconductor elements on a glass surface) and a temperature detection device used therefor.

[0002]

2. Description of the Related Art In order to improve the performance of a semiconductor device and reduce its variation, it is necessary to uniformly and accurately control the temperature of a semiconductor substrate or glass substrate during the manufacturing process of the semiconductor device. , Some measures have already been proposed.

For example, in the temperature detecting method described in Japanese Patent Laid-Open No. 4-98135, the temperature measuring element is covered with a cap made of a material having a high thermal conductivity to reduce the thermal resistance. Alternatively, the literature (JICST E91121096) shows an example in which an alumina tube is used as a support pin and a thermocouple is embedded inside the support pin.

In these conventional examples, the thermal resistance between the substrate to be measured and the temperature measuring body is reduced, but the thermal resistance between the temperature measuring body and the support base is not sufficiently taken into consideration. Therefore, a large amount of heat flows out from the substrate to be measured through the temperature measuring unit, which lowers the temperature of the substrate itself in the measuring unit.
In addition, there is a drawback that the temperature difference between the temperature measuring element and the substrate to be measured increases. Further, in the case where the temperature measuring element has a metal support such as SUS, there is a drawback that metal contamination (for example, Fe and Cr contamination) harmful to the substrate to be measured is generated.

Further, in the temperature measuring device described in Japanese Patent Laid-Open No. 4-148545, an example in which the temperature measuring element is inserted into the covering member is shown, but sufficient consideration should be given to the heat flow from the substrate to be measured. Not done. Further, Japanese Patent Laid-Open No. 4-363026 discloses an example in which a thermocouple for temperature measurement is heated.
For that reason, a heating source and a control system are required, and it cannot be denied that the configuration becomes complicated.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved semiconductor manufacturing apparatus which can control the temperature of a semiconductor substrate or a glass substrate uniformly and accurately and which does not cause harmful metal contamination. Providing a simple temperature detecting device.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a temperature detecting portion which also functions as a supporting pin of a semiconductor substrate or a glass substrate is formed by a material having a high thermal conductivity so that its tip (hereinafter referred to as a cap) is flat. The base is formed of an inorganic material having a lower thermal conductivity than the substrate, and the contact of the thermocouple is fixed to the cap through a hole provided in the base,
This can be solved by providing an infrared ray acceptor made of a material having a higher average emissivity in the wavelength range of 1 to 3 μm in the vicinity of the cap than the object to be heat-treated to be heat-treated.

The material of the cap is preferably aluminum or alumina for low temperature treatment, and alumina for high temperature treatment, and silicon nitride, silicon carbide or the like is also possible. Suitable materials for the infrared receptor are silicon carbide, carbon, and composites thereof. The material of the base is preferably quartz glass, a compound of magnesium oxide and silicon oxide such as steatite, or a compound of zirconium oxide and silicon oxide.

[0009]

According to the present invention, the temperature sensing element (the contact point of the thermocouple) is in contact with the substrate through the cap. At this time, the temperature difference between the temperature measuring unit and the temperature measuring unit of the substrate is the thermal resistance of the contact portion between the cap and the substrate, the thermal resistance of the cap, the thermal resistance of the cap and the temperature measuring unit, and the base (temperature measuring unit). It depends on the thermal resistance of the support). However, according to the present invention, by making the tip of the cap flat, the thermal resistance of the contact portion between the cap and the substrate is reduced, the material of the cap has a high thermal conductivity, and the thermal conductivity of the base is low. By doing so, the thermal resistance of the cap is reduced and the thermal resistance of the base is increased.

Further, by fixing the temperature measuring element to the cap through the tube of the base, the thermal resistance between the cap and the temperature measuring element is reduced. Therefore, in the temperature detecting device of the present invention, the thermal resistance between the temperature measuring element and the substrate is small, and the temperature difference between the temperature measuring element and the temperature measuring portion of the semiconductor substrate is extremely small. At the same time,
By constructing the base with a material with low thermal conductivity, providing a neck on the base, and reducing the cross section on the cap side, the thermal resistance of the base can be increased and the heat flow lost from the substrate can be reduced. , Reduce the temperature drop of the temperature measuring part of the board,
The temperature uniformity of the substrate can be ensured.

Further, by providing an infrared ray receptor made of a material having an average emissivity higher than that of the object to be heat-treated in the wavelength range of 1 to 3 μm in the vicinity of the cap, the wavelength range of 1 to 3 μm is mainly measured. The support pins are heated in the same manner as the object to be heated by receiving the heat rays from the infrared lamp, the ceramic heater, etc. that are radiated, and the temperature of the support pins approaches the temperature of the object to be heated, so that the heat flow lost from the substrate is further enhanced. It is possible to reduce the number, and it is possible to accurately measure the substrate temperature while ensuring the uniformity of the substrate temperature.

On the other hand, the infrared receptor is integrally formed of a material having a high thermal conductivity such as silicon carbide,
If most of the surface of the support pin is covered, a heat flow from the object to be heated will occur through the infrared receptor, so that the infrared receptor is more effective when it is composed of a plurality of parts which are not in contact with each other. Further, by confining the thermocouple inside the support pin and forming the support pin base by an inorganic material, it is possible to prevent the semiconductor substrate or the glass substrate from being contaminated with harmful metal.

[0013]

FIG. 1 shows an embodiment of the semiconductor manufacturing apparatus of the present invention. The apparatus main body 1 has a hollow structure as shown in the figure, and a reaction vessel 2 made of quartz glass is arranged in the central portion thereof. In the upper space and the lower space of the reaction vessel 2,
A plurality of heat ray irradiation lamps 3 (for example, halogen lamps) are arranged in parallel so as to vertically intersect. Although not shown, a trough-shaped concave reflecting mirror made of aluminum alloy coated with gold is disposed on the ceiling and floor inside the apparatus main body 1, so that the heating heat rays emitted from the heat ray irradiation lamp 3 are efficiently supplied. It is designed to collect light well toward the reaction container 2.

The external heat ray absorbing plates 4 are arranged in the upper and lower spaces (heat ray transmitting space) between the heat ray irradiation lamp 3 and the reaction vessel 2, respectively. In the case of the present embodiment, the absorption plate is made of quartz glass having a ground glass surface for heat ray diffusion formed on the surface, and a large number of vent holes for flowing cooling nitrogen gas are provided on the entire surface. 5 was formed. The semiconductor substrate 6, which is a non-processed product, was loaded on the heat ray permeable support base 7 installed at the bottom of the reaction vessel 2 with the guard ring 8 attached. On the other hand, the internal heat ray absorbing plate 9 was made of quartz glass, and was placed close to the semiconductor substrate 6 in the heat ray transmitting space therebelow. The absorbing plate can be arranged on both sides of the substrate 6 as required.

The reaction gas and the purge gas are introduced into the reaction vessel 2 from a gas introduction system (not shown) on the left side of the drawing, and after passing through the same vessel, a gas exhaust system (not shown) on the right side of the drawing.
Was evacuated using. Further, although not shown, a water passage is provided inside the wall of the apparatus main body 1, and during use of the apparatus,
The apparatus body 1 was cooled by passing cooling water through the water passage.

The temperature of the substrate 6 was measured through the observation window 11 and the through hole 13 by disposing the radiation thermometer 10 below the apparatus body 1. The measurement data was transferred to the power control device 12, and the power supplied to the heat ray irradiation lamp 3 was controlled based on the data. Alternatively, the temperature of the substrate 6 was measured by a thermocouple 15 incorporated in the support pin 14 of the heat ray transmissive support base 7, as shown in FIG.

The support pin 14 is constructed as shown in FIG. 2 (a) and comprises a cap 16 having a flat top made of alumina having a diameter of 4 mm and a base 17 made of a quartz glass tube having a diameter of 3.5 mm. The top of the base 17 is narrowed to a diameter of 2.5 mm to form a base neck 17a. On the surface of the base 17 made of a quartz glass tube, a plurality of ring-shaped silicon carbide films 18 are formed by chemical vapor reaction over a range of about 1 cm in length. The joint portion of the thermocouple 15 is fixed to the cap 16 with an inorganic adhesive. As in the case of the radiation thermometer, the measurement data was transferred to the power control device 12, and the power supplied to the heat ray irradiation lamp 3 was controlled based on the data. The radiation thermometer 10 and the thermocouple 15 were appropriately switched and used.

Besides, in order to prevent the temperature of each member from exceeding the allowable temperature and becoming high during use of the apparatus, nitrogen gas for cooling is blown into the gap between the apparatus main body 1 and the reaction vessel 2,
These parts were cooled.

When an unprocessed semiconductor substrate (silicon substrate) 6 was loaded into the reaction vessel 2 and annealed at a temperature of 1,000 ° C. by using such a manufacturing apparatus, the temperature variation among the substrates was found to be small. Good results were obtained at about 1 ° C.
When the same annealing treatment was performed using a silicon substrate having a polysilicon film formed on its surface and a silicon substrate having its surface doped with ions, the temperature control using the thermocouple 15 showed a good variation of about 1 ° C. However, in the temperature control using the radiation thermometer 10, the variation value was as large as about 10 ° C. Also, the temperature of the silicon substrate 6 and the thermocouple 1
The error from the temperature detected by No. 5 is about 3 ° C. which is constant, and it has been clarified that the temperature of the silicon substrate 6 can be accurately controlled by correcting this error of 3 ° C. Furthermore, the difference between the temperature of the silicon substrate near the support pin 14 in which the thermocouple 15 is embedded and the temperature of the substrate around it is as small as about 2 ° C., and the temperature of the substrate is uniform.
There was no time delay between the substrate temperature and the detected temperature, which was good.

For comparison, the base 17 is used as a support pin.
When a support pin having no silicon carbide ring formed on its surface is used, the error between the temperature of the silicon substrate 6 and the temperature detected by the thermocouple 15 is about 4 ° C., and the time between the substrate temperature and the detected temperature is The delay was about 3 seconds. Error about 4 with detected temperature
℃ was able to be corrected well, but the time delay had to be predicted and corrected in advance, and the correction amount changed each time the conditions such as the temperature rising speed changed, and there was no choice but to compose a very complicated program. It was

For further comparison, the support pin cap 1
6 is made of alumina with a diameter of 4 mm, and the base is also 4 mm in diameter.
When a quartz glass tube of mm was used and the same experiment as the conditions was performed, the error between the temperature of the silicon substrate 6 and the temperature detected by the thermocouple 15 was about 7 ° C., and the support pin 14 in which the thermocouple 15 was embedded was used. The difference between the temperature of the silicon substrate in the vicinity of and the temperature of the substrate in the vicinity was about 10 ° C., which was nonuniform. It is speculated that this is because quartz glass has a low thermal conductivity, but a large amount of heat flows into the support pins from the semiconductor substrate 6 because of its large cross-sectional area. Therefore, the thinner the support pin 14 is, the more suitable it is for temperature measurement. However, since the mechanical strength is weakened, it is also thermally convenient to thin the neck portion where stress is hard to concentrate.

Further, for comparison, both the cap 16 and the base 17 of the support pin were made of alumina having a diameter of 4 mm, and the same experiment as this condition was conducted. The temperature of the silicon substrate 6 and the thermocouple 15 were used. The error from the detected temperature is as large as about 15 ° C., and the value is not constant. Further, the difference between the temperature of the silicon substrate in the vicinity of the support pin 14 in which the thermocouple 15 is embedded and the temperature of the periphery thereof is about 40 ° C. And the substrate temperature was non-uniform. It is presumed that this is due to the low thermal resistance of the base portion 22 as well as the cause of the difference in degree.

As described above, in order to investigate the cause of non-uniformity of the substrate temperature when the semiconductor substrate temperature is measured with the support pins having low thermal resistance, the support base 7 and the guard of the semiconductor manufacturing apparatus shown in FIG. The ring 8 and the internal heat ray absorbing plate 9 are removed, and instead, the semiconductor substrate is directly placed on a ceramics heater, and the semiconductor substrate is heated by the heater, and the substrate temperature is set to 16 mm for both the cap 16 and the base 17 by alumina. The measurement was performed with the thermocouple 15 provided on the support pin formed in.

As a result, the difference between the temperature of the silicon substrate near the support pin 14 and the temperature of the substrate around it was reduced to about 5 ° C. Therefore, when the semiconductor substrate 6 is heated by the contact method, the amount of heat received from the heating body by the substrate is proportional to the temperature difference between the heating body and the substrate.
In contrast to the effect of reducing the temperature difference, when the semiconductor substrate 6 is heated by a non-contact method, for example, an infrared lamp, the amount of heat received by the substrate is equal, so that the heat partially flows out. Therefore, it is concluded that a temperature difference occurs around the support pin, and particularly when the temperature of the semiconductor substrate 6 is high and the thermal resistance of the support pin is low, the temperature change of the semiconductor substrate becomes large around the support pin.

FIG. 3 shows another embodiment of the present invention for forming a silicon oxide film on a silicon substrate. In this embodiment, the low pressure mercury lamp 20 is provided in the upper space of the reaction vessel 2.
A (ultraviolet lamp) was arranged, and a halogen lamp 3 (heat ray irradiation lamp) was arranged in the lower space of the reaction vessel 2.

The support pin 14 is as shown in FIG. 2 (b), the cap 16 is made of aluminum, and the top of the base 17 made of a quartz glass tube is squeezed to have a diameter of 2.5 mm.
7a, and a ring made of silicon carbide having a length of about 6 mm is fitted to the base 17a. Other structures are
It is substantially the same as the case of the first embodiment. The internal heat ray absorbing plate 9 has been removed.

A reaction gas composed of monosilane gas and laughing gas is introduced into the reaction vessel 2, and the silicon substrate 6 maintained at a temperature of 150 ° C. is irradiated with ultraviolet rays having a wavelength of 185 nm to form a silicon oxide film on the silicon substrate 6. Was formed. Both temperature control by thermocouple and temperature control by radiation thermometer, substrate temperature variation (reproducibility), uniformity,
Moreover, the temperature error was extremely good, and a silicon oxide film having a desired high quality could be formed.

Further, with the same apparatus configuration as that of FIG. 3, ozone gas was used as a reaction gas, and the resist on the substrate was removed. The substrate was maintained at 250 ° C., and the ultraviolet intensity on the substrate was about 100 mW / cm ² . Ozone-containing oxidizing gas was flowed at a flow rate of 10 liters / minute in a gap of 0.5 mm from the surface of the substrate to oxidize the resist. At this time, the resist oxidation rate (processing rate) was changed by about 2% with respect to the substrate temperature change of 1 ° C. When the substrate temperature is low, the reaction speed becomes slow, so when the substrate temperature is low at the support pin portion, unreacted residue remains only at that portion.

When the support pin of the present invention shown in FIG. 2 (c) was used, the resist processing speed was 0.95 or more in the ratio of the slow portion to the fast portion, and it was confirmed that there was no problem in uniformity. In the support pin 14 used in this embodiment, the cap 16 is made of silicon carbide and is mechanically held by being inserted into the base 17 made of a quartz glass tube. Base 1
7, a ring-shaped silicon carbide film 18 is formed by chemical vapor reaction over a range of about 5 mm in length. The thermocouple 15 is covered with an aluminum tube 21 at its joint, and the cap 1
6 and is mechanically held. The other structure is substantially the same as that of the first embodiment.

FIG. 4 shows another embodiment of the present invention in which a mechanism 19 for adjusting the contact angle between the support pin 14 and the substrate 6 (angle formed by the surface of the cap 16 and the surface of the substrate 6) is provided. It is a figure. The support pin 14 can be rotated around it by an angle adjusting mechanism 19, and even if the substrate 6 is tilted, the cap 16 is adjusted so as to make surface contact (contact angle 0 degree) with the substrate 6.

The cap 16 of the support pin 14 has a flat top portion in order to reduce the thermal resistance with the substrate 6, but if the substrate 6 is tilted due to warping or the like, the substrate 6 is
The contact area between the support pin 14 and the support pin 14 is not sufficient, and the detected temperature error increases. In this case, since the detected temperature becomes lower than the actual temperature of the substrate 6, the angle of the support pin is slightly moved by the angle adjusting mechanism 19, and the temperature at the position where the detected temperature becomes maximum is taken as the detected temperature. Control heating power. While this angle adjustment is being performed, temperature control is performed based on other measured temperature data, or the temperature control is kept constant.

In particular, when the substrate 6 is heated in vacuum, the change in the detected temperature due to the contact angle is large and the contact angle is 1 or less.
When the contact angle was adjusted to 0 degrees, the difference between the substrate temperature and the detected temperature was about 10 degrees Celsius.
And decreased.

In the embodiment, the halogen lamp is used as the heat ray irradiation lamp 3 for heating the silicon substrate, but an infrared lamp or a ceramic heater may be used in a non-contact type. Further, in the embodiment, the case where the semiconductor substrate is used as the substrate to be heated has been described, but the same applies when the glass substrate is used. However, when the glass substrate is used, the thermal conductivity of the substrate is lower than the thermal conductivity of the silicon substrate, so that the temperature uniformity of the substrate is further deteriorated. Furthermore, although the case where quartz glass is used as the material of the base portion 22 of the support pin has been described, the material of the base portion 22 is MgO.SiO ₂ , 2MgO.
Ceramics containing silicon oxide such as SiO ₂ and ZrO ₂ · SiO ₂ are suitable. In any case, the effects of the present invention can be obtained as long as the thermal conductivity of the material of the base 17 is sufficiently lower than the thermal conductivity of the substrate and the cap 16. Further, although silicon carbide was used as the infrared acceptor in the examples, even if silicon carbide is formed on carbon or a carbon material, the same effect can be expected because the infrared absorbing function is the same.

[0034]

According to the temperature detecting device of the semiconductor manufacturing apparatus of the present invention, the thermal resistance of the temperature sensing element and its surroundings is lowered, the thermal resistance of the supporting portion is increased, and the temperature of the supporting portion is set to the temperature of the object to be heated. By bringing them close to each other, the temperature of the semiconductor substrate or the glass substrate can be accurately measured, and the temperature unevenness of these substrates can be reduced, and the base of the support pin is made of an inorganic material to prevent harmful metal contamination. You can do it.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a semiconductor manufacturing apparatus of the present invention.

FIG. 2 is a sectional view of a main part of a temperature detection device of a semiconductor manufacturing apparatus according to the present invention.

FIG. 3 is a sectional view showing a second embodiment of the semiconductor manufacturing apparatus of the present invention.

FIG. 4 is an explanatory diagram of a second main part of the temperature detecting device of the semiconductor manufacturing apparatus of the present invention.

[Explanation of symbols]

14 ... Support pin, 15 ... Thermocouple, 16 ... Cap, 17
... base, 17a ... base neck, 18 ... infrared receptor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sukeyoshi Tsunekawa 888 Fujihashi, Ome City, Tokyo Hitachi Ltd. Heater Lighting Division

Claims (5)

[Claims] 1. In a temperature detecting device of a semiconductor manufacturing apparatus for heat-treating a semiconductor substrate or a glass substrate in a non-contact manner, a thermocouple is embedded in at least one of support pins for supporting these substrates, and a tip portion of the support pin is provided. The support pin is flatly configured with a material having a higher thermal conductivity than the base portion, and the base portion of the support pin is configured with an inorganic material having a lower thermal conductivity than the substrate, and near the tip portion of the support pin, A temperature detecting device comprising an infrared receptor made of a material having an average emissivity higher than that of the object to be heat-treated in the wavelength range of 1 to 3 μm. 2. The temperature detecting device according to claim 1, wherein the infrared receptor is composed of silicon carbide, carbon, or a composite thereof. 3. The temperature according to claim 1, wherein the base of the support pin is tubular, a thermocouple is inserted so that the contact is located at the tip of the tube, and the vicinity of the contact is fixed to the tip of the support pin. Detection device. 4. The temperature detecting device according to claim 1, further comprising an angle adjusting mechanism for varying a contact angle between the tip of the support pin and the substrate. 5. A heat ray transmissive reaction container for accommodating a semiconductor substrate or a glass substrate, and a heat ray source for irradiating at least one surface of the substrate with a heat ray for heating from the outside of the reaction vessel, A semiconductor manufacturing apparatus comprising the temperature detecting device according to claim 1, 2, 3, or 4.