JPH11329991A - Rapid heat processing device and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rapid heat processing device and its method in which temperature decreasing of a wafer surface caused by a cool reaction gas from a gas introducing port and exhausting from a gas exhausting port is prevented to always equalize the temperature on the wafer surface. SOLUTION: A rapid heat processing device which has a reaction gas introducing port 6 at a terminal of a quartz tube 2 inserting and arranging wafers 1 one by one and an exhausting port 7 at another terminal, and which is provided with heating lamps 7 at both upper and lower surface sides of the wafers 1, is provided with a previous heating means 15 for the reaction gas at the windward of the reaction gas introducing port 6. By the constitution, the reaction gas is previously heated, therefore equality of the wafer surface temperature is enhanced without the temperature at the gas introducing side in the rapid heat processing device being decreased caused by cool reaction gas flowing from the gas introducing port 6 as conventional.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rapid heating apparatus and method. More specifically, the present invention relates to a rapid heat treatment apparatus and method for making the surface temperature of a wafer uniform in a heat treatment step in a semiconductor manufacturing process.

[0002]

2. Description of the Related Art Conventionally, when a semiconductor element is formed on a wafer, impurity ions implanted into the wafer by an ion implanter are reduced to, for example, 80% by a low-speed heat treatment apparatus (diffusion furnace).
Diffusion was formed by heat treatment at 0 to 900 ° C. for 30 to 60 minutes at an intermediate temperature for a long time. However, in recent years, with the miniaturization and high integration of semiconductor devices, the speed of elements, the dielectric constant of electrodes, and the miniaturization and lamination of wiring layers have been advanced.

For this reason, impurity ions implanted by an ion implanter are diffused without using a conventional medium-temperature and long-time diffusion furnace in order to satisfy the high-speed operation of the device accompanying the miniaturization and high integration of the device. Using a rapid heat treatment apparatus (lamp annealer) that only activates without causing
The element is formed by a high-temperature and short-time heat treatment at 100 to 1100 ° C. for 10 to 60 seconds. In addition, such a rapid heating apparatus has come to be used for forming an electrode having a low dielectric constant and a fine wiring layer.

Hereinafter, a conventional rapid heating apparatus will be described with reference to FIGS. 3 and 4. FIG. FIG. 3 is a sectional structural view of a conventional rapid heating apparatus, and FIG. 4 is a view of the conventional rapid heating apparatus as viewed from above. As shown in FIG. 3, the rapid heating apparatus comprises a quartz tube 2 for accommodating a wafer 1, a heating lamp 3 comprising halogen lamps for heating the wafer 1 from both upper and lower surfaces, and efficiently reflecting light from the heating lamp 3. It is constituted by an aluminum chamber 4 coated with gold.

As shown in FIG. 4, the heating lamp 3 has a rod-like shape, and a plurality of heating lamps 3 are arranged in parallel along the flow direction A of the reaction gas. The chamber 4 is provided with a door 5 from which the wafer 1
In and out. The chamber 4 is provided with a cooling gas introduction hole 8 for cooling nitrogen gas or the like. A reaction gas (N ₂ , O ₂ , NH ₃ , N ₂ O, HCl, etc.) is supplied into the quartz tube 2 from a gas inlet 6 at one end of the quartz tube 2, and reacts with the wafer 1 at a high temperature to react with the gas. Air is exhausted from the exhaust port 7.

At this time, the quartz tube 2 is connected to a heating lamp 3
(Halogen lamp) Light (wavelength: 0.3 to 7.0 μm) is transmitted at a transmittance of 90% or more, so that the temperature is not raised to 200 ° C. or more. Therefore, the quartz tube 2 is not heated and the wafer 1 is not heated.
Only the lamp absorbs the light of the halogen lamp and rapidly rises in temperature. At this time, light of a specific wavelength emitted from the heated wafer 1 passes through the transmission hole 9 of the chamber 4, and its light intensity is measured by the radiation thermometer 10. Thus, the temperature of the wafer 1 is detected, and the temperature of the wafer 1 can be controlled and heat-treated while monitoring the temperature.

The relationship between temperature change and time in such a rapid heating apparatus will be described below. FIG. 5 is a diagram showing the relationship between the temperature in the quartz tube 2 and time. In FIG. 5, the horizontal axis represents time, and the vertical axis represents temperature. The quartz tube 2
Inside is always set to 200 ° C. or higher. At time T ₀ , the wafer 1 is loaded into the quartz tube 2. After time T ₁ that, the temperature started to be raised. This heating condition is 50 to
The temperature is increased to a heat treatment temperature of 500 to 1200 ° C. at a temperature increasing rate of 100 ° C. To the heat treatment temperature (500 to 1200 ° C.) the heating time T ₂ has reached the stopping constant heat treatment temperature at the time from the time T ₂ of the few tens of seconds T ₃ subjected to heat treatment. When the heat treatment is completed, the quartz tube is cooled at a cooling rate of 50 to 100 ° C. per second.

The cooling is stopped at a time T ₄ when the temperature in the first quartz tube 2 has dropped to 200 ° C. This cooling is performed by supplying nitrogen gas into the chamber from a nitrogen gas introduction hole 8 provided in the chamber 4. The temperature in the quartz tube 2 in a series of operations from T ₁ to T ₄ is such that light of a specific wavelength emitted from the wafer 1 that has been heated by absorbing the light of the heating lamp 3 and rising into the chamber 4 as described above. It passes through the transmission hole 9 provided and is measured and adjusted by the radiation thermometer 10. Thereafter, unloading the wafer 1 from the quartz tube 2 at time T _5.

In order to keep the surface temperature of the wafer 1 constant, a plurality of heating lamps 3 arranged in parallel along the flow direction of the reaction gas and separated from each other can be individually controlled. This prevents variations in the reaction due to temperature differences within the surface of the wafer 1.

[0010]

However, a low-temperature reactant gas flows from the reactant gas inlet 6 and the heated reactant gas is exhausted from the reactant gas exhaust port 7 so that heat is taken away. The temperatures of the gas inlet side and the reaction gas exhaust side become low.

FIG. 6 is a surface temperature distribution diagram of the wafer 1 processed by such a conventional rapid heating apparatus. As shown in the figure, the temperature at the center of the wafer 1 is high, the temperatures at the gas introduction side and the gas exhaust side are low, and the in-plane temperature distribution becomes non-uniform. When such a temperature distribution occurs, the characteristics of the device are varied, and the device may be unstable. In order to prevent this, as described above, the heating lamps 3 separated with respect to the flow direction A of the reaction gas (FIG. 4) are individually controlled, and the temperature is adjusted to adjust the temperature of the gas introduction side and the exhaust side of the wafer 1. Even if the temperature is increased, the temperature at the center of the wafer rises with this, and there is a limit in eliminating the temperature difference between the center of the wafer, the gas inlet side, and the gas exhaust side.

The present invention has been made in consideration of the above prior art, and is intended to prevent a temperature drop on a wafer surface due to a cold reaction gas from a gas inlet and exhaustion from a gas exhaust port, and to improve an in-plane temperature distribution. It is an object of the present invention to provide a rapid heat treatment apparatus and a method thereof in which the surface temperature of a wafer is always uniform.

[0013]

In order to achieve the above object, according to the present invention, a quartz gas tube for inserting and arranging wafers one by one has a reaction gas introduction port at one end and an exhaust port at the other end. A rapid heating apparatus having a plurality of heating lamps on the upper and lower surfaces of the wafer, wherein a reactive gas preheating means is provided upstream of the reaction gas inlet. I do.

According to this configuration, since the reaction gas is pre-heated by the preheating means, a cold reaction gas flows from the gas inlet as in the prior art, and the temperature on the gas inlet side in the rapid heating apparatus decreases. In other words, the surface temperature uniformity of the wafer is improved. In addition, since a stable and reliable preheating effect is achieved with a simple structure, a constant and stable heat treatment effect can be obtained without any variation even when the device is repeatedly operated, so that rapid heating with good reproducibility can be performed.

In a preferred configuration example, the reaction gas passage passing through the preheating means is formed by a bent return passage.

According to this configuration, the time required for the reaction gas to pass through the preheating means is increased, and the reaction gas is sufficiently reliably heated.

In another preferred embodiment, the heating lamp on the exhaust port side is provided so as to be individually controllable in a plurality of directions in a direction perpendicular to the flow direction of the reaction gas.

According to this configuration, since a plurality of heating lamps are arranged separately along the direction perpendicular to the flow direction of the reaction gas, fine temperature control of the wafer surface is possible, and the wafer surface temperature can be controlled. Uniformity is further improved.

Further, in the present invention, a reaction gas inlet is provided at one end of a quartz tube into which wafers are inserted and arranged one by one.
In the rapid heat treatment method having an exhaust port at the other end and heating the wafer from both upper and lower sides of the wafer arranged in the quartz tube, the reactant gas is introduced before introducing the reactant gas into the quartz tube. And heating the wafer surface on the exhaust port side by a heating lamp provided so as to be individually controllable in a direction perpendicular to the flow direction of the reaction gas. .

According to this configuration, since the reaction gas is pre-heated by the preheating means, a cold reaction gas flows from the gas inlet as in the prior art, and the temperature on the gas inlet side in the rapid heating apparatus decreases. In other words, the surface temperature uniformity of the wafer is improved. In addition, since a stable and reliable preheating effect is achieved with a simple structure, a constant and stable heat treatment effect can be obtained without any variation even when the device is repeatedly operated, so that rapid heating with good reproducibility can be performed. Further, since the plurality of heating lamps are separately arranged along the direction perpendicular to the flow direction of the reaction gas, fine temperature control of the wafer surface is possible, and the uniformity of the wafer surface temperature is further improved.

In a preferred embodiment, the reaction gas is heated to a temperature equal to or higher than the heat treatment temperature of the wafer before introducing the reaction gas into the quartz tube.

According to this configuration, since the reaction gas introduced into the quartz tube is at a temperature higher than the wafer heat treatment temperature,
An efficient temperature-raising action of the quartz tube is obtained, the time required for the temperature rise is shortened, the productivity is increased, and the reaction gas at a higher temperature than the central portion of the wafer is supplied, so that the temperature distribution becomes uniform.

[0023]

FIG. 1 is a sectional structural view of a rapid heating apparatus according to an embodiment of the present invention, and FIG. 2 is a top view of the rapid heating apparatus according to the embodiment of the present invention. It is. The structure of the quartz tube 2 and the chamber 4 in this embodiment is substantially the same as the structure of the conventional quartz tube 2 and the chamber 4 shown in FIG.
That is, the quartz tube 2 accommodates only one wafer 1 and includes a heating lamp 3 composed of a halogen lamp for heating the wafer 1 from both upper and lower surfaces. Gold coated for good reflection.

The rapid heating apparatus comprises a quartz tube 2 for accommodating a wafer 1, a heating lamp 3 composed of halogen lamps for heating the wafer 1 from above and below, and a light source for reflecting the light of the heating lamp 3 efficiently. It is composed of a gold-coated aluminum chamber 4.

As shown in FIG. 1, the heating lamp 3 has a rod shape, and a plurality of heating lamps 3 are arranged in parallel along the flow direction A of the reaction gas. The chamber 4 is provided with a door 5 from which the wafer 1
In and out. The chamber 4 is provided with a cooling gas introduction hole 8 for cooling nitrogen gas or the like. A reaction gas (N ₂ , O ₂ , NH ₃ , N ₂ O, HCl, etc.) is supplied into the quartz tube 2 from a gas inlet 6 at one end of the quartz tube 2, and reacts with the wafer 1 at a high temperature to react with the gas. Air is exhausted from the exhaust port 7.

At this time, the quartz tube 2 is
(Halogen lamp) Light (wavelength: 0.3 to 7.0 μm) is transmitted at a transmittance of 90% or more, so that the temperature is not raised to 200 ° C. or more. Therefore, the quartz tube 2 is not heated and the wafer 1 is not heated.
Only the lamp absorbs the light of the halogen lamp and rapidly rises in temperature. At this time, light of a specific wavelength emitted from the heated wafer 1 passes through the transmission hole 9 of the chamber 4, and its light intensity is measured by the radiation thermometer 10. Thus, the temperature of the wafer 1 is detected, and the temperature of the wafer 1 can be controlled and heat-treated while monitoring the temperature.

In this embodiment, a preheating means 15 connected to the gas inlet 6 is provided. The preheating means 15 is composed of a quartz tube 11, a heater 12 around the quartz tube 11, for example, composed of an electric heating coil, and a buffer quartz 13 in a comb shape. The quartz tube 11 has a gas inlet 14, and the injected reaction gas is a buffer quartz 13.
Is passed through a convoluted and bent passage formed by the above, and is heated beforehand by a heater 12 provided around the quartz tube 11 before being introduced into the quartz tube 2 and sent to the gas introduction port 6.

At this time, since the bent passage is formed by the buffer quartz 13 in the quartz tube 11, the quartz tube 11 when the reaction gas passes through the quartz tube 11 is formed.
The residence time in the inside becomes long, and the heater 12 receives a sufficient heating action. In this case, it is desirable that the preheating temperature of the reaction gas be equal to or higher than the heat treatment temperature of the wafer 1.
Thereby, when the reaction gas is introduced into the quartz tube 2, the action of increasing the temperature of the quartz tube 2 is enhanced, the time required for the heating is shortened, the productivity is increased, and the reaction gas having a higher temperature than the central portion of the wafer is supplied. Therefore, the uniformity of the temperature distribution is ensured.

As shown in FIG. 2, the heating lamps 3 on the gas introduction side are arranged in parallel along the flow direction A of the reaction gas, while a plurality of heating lamps (halogen lamps) 3a are arranged on the gas exhaust side. The rows are provided separately in the direction perpendicular to the gas flow direction A, and can be individually controlled. As a result, the temperature of the surface of the wafer 1 on the gas exhaust side can be accurately adjusted, and the uniformity of the temperature distribution can be further improved. The heating lamps 3 and 3a are not limited to halogen lamps, but may be infrared lamps having a wavelength of about 0.1 to 7.0 μm or other lamps.

[0030]

Example: Conditions of rapid heating apparatus Lamp: Infrared halogen lamp Lamp emission wavelength: 0.3 to 7.0 μm Lamp rating: 170 V 1.7 kW Number of lamps: 14 each for upper and lower sides, 2 each for left and right Chamber: made of aluminum and made of gold Coating, water-cooled quartz tube: N ₂ cooling 25 (l) / min Radiation thermometer wavelength: 2.7 μm Quartz tube heater for preheating Temperature control: 1000 ° C. Rapid heating treatment (see FIG. 5) Loading: 200 ° C. Heating rate : 50 ° C./sec Heat treatment: 1000 ° C. for 10 sec Gas: N ₂ 3 (l) / min Cooling rate: 50 ° C./sec Unloading: 200 ° C. Temperature uniformity within wafer surface ± 2.0 ° C. by the above examples.
It was confirmed that processing could be performed at a stable temperature. The conditions for performing the rapid heat treatment are as follows: N ₂ , O ₂ , N
Normal conditions using H ₃ , N ₂ O, HCl gas or the like may be used. The temperature may be a normal condition of 500 ° C to 1200 ° C.

[0031]

As described above, in the present invention, since the preheated reaction gas is introduced into the quartz tube, the temperature on the gas inlet side of the wafer does not decrease as in the prior art. The uniformity of the wafer surface temperature is improved. In addition, since a stable and reliable preheating effect is achieved with a simple structure, a constant and stable heat treatment effect can be obtained without any variation even when the device is repeatedly operated, so that rapid heating with good reproducibility can be performed. As a result, it is possible to form a highly reliable high-speed element, a low dielectric constant electrode, and a wiring layer.

[Brief description of the drawings]

FIG. 1 is a sectional structural view of a rapid heating apparatus according to an embodiment of the present invention.

FIG. 2 is a top view of the rapid heating apparatus according to the embodiment of the present invention.

FIG. 3 is a sectional structural view of a conventional rapid heating apparatus.

FIG. 4 is a view of a conventional rapid heating apparatus as viewed from above.

FIG. 5 is a diagram showing the relationship between temperature and time in a quartz tube.

FIG. 6 is a diagram showing a wafer surface temperature distribution during processing by a conventional rapid heating processing apparatus.

[Description of Signs] 1: wafer, 2: quartz tube, 3, 3a: heating lamp, 4: chamber, 5: door, 6: gas inlet, 7:
Gas exhaust port, 8: cooling gas introduction hole, 9: transmission hole, 10:
Radiation thermometer, 11: quartz tube, 12: heater, 13: buffer quartz, 14: gas inlet, 15: preheating means.

Claims (5)

[Claims] A quartz tube into which wafers are inserted one by one has a reaction gas inlet at one end, an exhaust port at the other end, and a plurality of heating lamps on the upper and lower surfaces of the wafer. In the rapid heating apparatus, a preheating means for the reaction gas is provided upstream of the reaction gas inlet. 2. The rapid heating apparatus according to claim 1, wherein the reaction gas passage passing through the preheating means comprises a bent return passage. 3. The rapid heating apparatus according to claim 1, wherein a plurality of the heating lamps on the exhaust port side are individually controllable in a direction perpendicular to a flow direction of the reaction gas. . 4. A quartz tube into which a wafer is inserted one by one and having a reaction gas inlet at one end and an exhaust port at the other end, and a wafer placed in this quartz tube from both upper and lower sides of the wafer. In the rapid heat treatment method, the reaction gas is heated in advance before introducing the reaction gas into the quartz tube, and a plurality of wafer surfaces on the exhaust port side are arranged in a direction perpendicular to the flow direction of the reaction gas. A rapid heat treatment method characterized in that heat treatment is performed by heating lamps individually controllable. 5. The rapid heating method according to claim 4, wherein the reaction gas is heated to a temperature equal to or higher than the heat treatment temperature of the wafer before introducing the reaction gas into the quartz tube.