JPH10256245A - Wafer heat-treatment and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a yield in manufacturing a semiconductor device by preventing deterioration of a sheet resistance, in-plane uniformity and film thickness distribution of wafers caused by heat treatment. SOLUTION: In this apparatus, a horizontal diffusion furnace 1 heats inside of a furnace core tube, 2 while introducing a process gas into the tube 2, thereby heat-treating wafers 30 transported into the tube 2. A heating device for preliminary heating of the process gas is provided in an introductory path of the process gas. In this case, the heating device comprises, e.g. a preliminary heating tube 8 provided within the furnace core tube 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a wafer heat treatment apparatus used for manufacturing semiconductor devices and a method thereof.

[0002]

2. Description of the Related Art As a conventional wafer heat treatment apparatus, for example, a horizontal diffusion furnace 20 as shown in FIG. 3 is known. The horizontal diffusion furnace 20 mainly includes a furnace core tube 21 and a heater 22 provided on the outer periphery of the furnace core tube 21. For example, one end of the furnace core tube 21 in the longitudinal direction is a front side. , The other end side being the rear side. A front side of the furnace core tube 21 is a loading / unloading port 23 for the wafer 30.
Is attached. A process gas introduction pipe 25 is connected to the front side of the furnace core tube 21, and an exhaust pipe 26 is connected to the rear side thereof.

In such a horizontal diffusion furnace 20, the heater 2
The boat 31 containing the wafer 30 is loaded into the furnace core tube 21 heated to the processing temperature in Step 2 through the loading / unloading port 25, and a process gas such as N ₂ gas or the like is introduced into the furnace core tube 21 from the introduction tube 23. The wafer 30 is heat-treated by exhausting it from the exhaust pipe 24 while introducing the inert gas.

[0004]

However, in the conventional wafer heat treatment apparatus, for example, in the case of the above-mentioned horizontal diffusion furnace, while the inside of the furnace core tube is heated to the processing temperature during the heat treatment of the wafer, there is no temperature treatment. , Ie, a process gas cooled to the temperature in the furnace core tube is introduced into the furnace core tube. For this reason, in the conventional horizontal diffusion furnace in which the process gas is introduced into the furnace core tube from the front side of the furnace core tube and exhausted from the rear side as described above, the inside of the furnace core tube is cooled by the cooled process gas, The temperature inside the furnace tube is not stable. As a result, when a diffusion layer or a film is formed by performing a heat treatment on a wafer using this horizontal diffusion furnace, the heat treatment is not uniformly performed on the wafer surface, and the uniformity of the sheet resistance value (ρ _s ) on the wafer surface is not uniform. And the film thickness distribution becomes poor.

[0005] For example a wafer plane uniformity of [rho _S ion implantation layer after the impurity is ion-implanted into the wafer is about 1.5%
In the vicinity, after the heat treatment for activating the impurities in the ion-implanted layer is performed, the uniformity of ρ _s of the obtained diffusion layer in the wafer surface deteriorates to about 4% to 5%. Such ρ
The deterioration of the uniformity of the _{S in} the wafer surface and the deterioration of the film thickness distribution cause a decrease in the manufacturing yield of the semiconductor device.

Therefore, it is possible to prevent the deterioration of the uniformity of ρ _{S in} the wafer surface and the deterioration of the film thickness distribution due to the heat treatment, and it is desired to develop a wafer heat treatment apparatus and a heat treatment method capable of improving the production yield of semiconductor devices. ing.

[0007]

In order to solve the above-mentioned problems, a wafer heat treatment apparatus according to the present invention heats the inside of a chamber while introducing a process gas into the chamber, and heat-treats the wafer transferred into the chamber. And a heating section for preheating the process gas is provided in a process gas introduction path.

According to the present invention, since the heating section for the process gas is provided in the passage for introducing the process gas, the heating section is required when the heat treatment using the process gas is stable even at a temperature near the heating temperature in the chamber. It is possible to introduce the process gas into the chamber after preheating the process gas near the heating temperature in the chamber. Therefore, even if the process gas is introduced into the chamber and exhausted during the heat treatment, the temperature in the chamber is prevented from being lowered by the process gas, and the temperature in the chamber is always stabilized.

Further, in the wafer heat treatment method according to the present invention, the process gas is heated in the chamber in advance by heating the chamber while introducing the process gas into the chamber to heat-treat the wafer transferred into the chamber. The method is characterized in that preheating is performed to a temperature near the temperature, and then the preheated process gas is introduced into the chamber.

According to the present invention, before the process gas is introduced into the chamber, the process gas is preliminarily heated to a temperature near the heating temperature in the chamber. However, the temperature in the chamber is not reduced by the process gas. Therefore, since the processing temperature is always stable, the uniform wafer is heat-treated in the wafer plane.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a wafer heat treatment apparatus and method according to the present invention. Here, an example in which the apparatus of the present invention is applied to a horizontal diffusion furnace will be described. FIG. 1 is a schematic configuration diagram showing a first embodiment of the apparatus of the present invention, and shows a state where a wafer is being heat-treated. The difference between the horizontal diffusion furnace 1 of the present embodiment and the conventional horizontal diffusion furnace is that a process gas introduction path into a furnace core tube 2 serving as a chamber is provided with a preliminary portion serving as a heating unit for preheating the process gas. That is, the heating tube 8 is provided.

That is, in the horizontal diffusion furnace 1, a heater 3 is provided on the outer periphery of a furnace core tube 2 made of quartz, as in the prior art. For example, when one end in the longitudinal direction of the furnace core tube 2 is the front side and the other end is the rear side, the front side of the furnace core tube 2 is the loading / unloading port 4 for the wafer 30. A furnace lid 5 that opens and closes when the wafer 30 is carried in and out is attached to the entrance 4. A gas stable near the heat treatment temperature of the wafer 30, for example, N ₂ gas, Ar
An inlet pipe 6 for a process gas such as an inert gas such as a gas, O ₂ gas, or H ₂ gas is connected, and an exhaust pipe 7 is connected to a front peripheral wall of the furnace core pipe 2.

The preheating tube 8 is formed by extending into the furnace core tube 2 from the end of the process gas introduction tube 6 connected to the furnace core tube 2, and is formed at the rear side in the furnace core tube 2. Is provided. At this time, the preheating tube 8 is spirally provided along the inner wall of the furnace core tube 2 from a rear portion of the furnace core tube 2 toward a position where the wafer 30 is arranged. Further, the front end of the preheating tube 8 is extended so as to return to the rear side of the furnace core tube 2 so that the process gas can be distributed throughout the furnace core tube 2. It is bent so as to face the front side of the tube 2. The preheating tube 8 is made of a material that does not react with the process gas and has good heat conductivity, for example, stainless steel.

A temperature detector is provided near the process gas outlet of the preheating tube 8 so that the temperature of the process gas blown from the preheating tube 8 can be monitored. Alternatively, the power consumption of the heater 3 at the position where the preheating tube 8 of the furnace core tube 2 is arranged can be monitored, and the process blown out from the preheating tube 8 based on the monitoring result of the power consumption. The temperature of the gas can be determined. Then, the supply power of the heater 3 at the position where the preheating tube 8 of the furnace core tube 2 is arranged can be adjusted based on the monitoring result so that the temperature of the process gas is heated to around the heating temperature of the furnace core tube 2. It is configured as follows.

In the horizontal diffusion furnace 1 formed as described above, since the preheating tube 8 is formed to extend from the end of the process gas introduction pipe 6, the process gas passing through the introduction pipe 6 is further preheated. After passing through the tube 8, it is introduced into the furnace core tube 2 from the preheating tube 8.

Next, the wafer 3 using the horizontal diffusion furnace 1
An embodiment of the wafer heat treatment method according to the present invention will be described based on the heat treatment method No. 0. First, when the wafer 30 is heat-treated, the inside of the furnace core tube 2 is heated to the processing temperature by the heater 3 in advance, and the process gas is preliminarily heated to a temperature near the heating temperature in the furnace core tube 2 by the preheating tube 8. Heat. As described above, in the horizontal diffusion furnace 1, the preheating tube 8
Is provided in the furnace core tube 2, so that the preheating tube 8 is heated to a temperature near the inside of the furnace core tube 2 by the heat in the furnace core tube 2. Therefore, the process gas preheated to a temperature near the inside of the furnace core tube 2 is obtained by passing the process gas from the introduction tube 6 through the preheating tube 8.

Then, the preheated process gas is exhausted from the exhaust pipe 7 while being introduced into the furnace core tube 2 from the preheating tube 8, and a plurality of wafers 30 stored in the boat 31 are removed from the furnace core tube 2. The wafer 30 is heat-treated.

In the above-described heat treatment method for the wafer 30, the process gas is preliminarily heated to near the temperature in the furnace core tube 2, and then the process gas is introduced into the furnace core tube 2. Even if the process gas is exhausted while being introduced into the furnace 2, the temperature in the furnace core tube 2 is not lowered by the process gas. As a result, the temperature in the furnace core tube 2 is always stable, and the wafer 30 can be uniformly heat-treated within the wafer 30 surface.

In the horizontal diffusion furnace 1 of this embodiment, the process gas can be preheated to a temperature near the heating temperature in the furnace core tube 2 by the preheating tube 8, so that the above-described heat treatment method can be reliably performed. it can. Therefore, according to the horizontal diffusion furnace 1 and the heat treatment method of the first embodiment,
Since the uniformity of ρ _{S in} the wafer surface and the film thickness distribution in the wafer surface can be improved, the production yield of the semiconductor device can be improved.

Further, in the horizontal diffusion furnace 1, the preheating tube 8 is provided in the furnace core tube 2 and is heated at the temperature in the furnace core tube 2, so that a heating means for preheating the process gas is newly provided. Even without the provision, the process gas can be heated to a temperature near the inside of the furnace core tube 2 via the preheating tube 8. Moreover, since the preheating tube 8 is provided in a spiral shape along the inner wall of the furnace core tube 2, the preheating tube 8 is long. The preheating can be performed to a temperature near the inside of the furnace core tube 2. Therefore, since no new heating means is required, the configuration of the apparatus is not complicated, the cost required for the apparatus can be reduced, and electric energy is saved because the heat in the furnace core tube 2 is effectively used. be able to.

In the first embodiment, the case where the heating section in the apparatus of the present invention is constituted by a preheating tube has been described.
What is necessary is just to be provided in the process gas introduction path so that the process gas can be pre-heated, and it is not limited to this example. Also, an example in which the heating unit is provided in the furnace core tube has been described,
For example, the heating unit 11 may be provided outside the furnace core tube 2 like the horizontal diffusion furnace 10 of the second embodiment shown in FIG.

That is, in the horizontal diffusion furnace 10, the heating section 11 is interposed between the end of the process gas introduction pipe 6 on the furnace core tube 2 side and the furnace core tube 2. The heating unit 11 extends from the end of the introduction tube 6 and is formed in a spiral shape.
and heating means 11b for heating the heating tube 11a so that the process gas passing through the inside of the heating tube 11a is heated to a temperature near the heating temperature in the furnace core tube 2. The heating tube 11a is connected to a rear portion of the furnace core tube 2. The heating tube 11a is made of a material that does not react with the process gas and has good thermal conductivity, for example, stainless steel.

In the horizontal diffusion furnace 10, the process gas that has passed through the introduction pipe 6 passes through the heating pipe 11a, and is preheated to a temperature near the heating temperature in the furnace core tube 2 at that time. Thereafter, the preheated process gas is introduced into the furnace core tube 2. Therefore, according to the horizontal diffusion furnace 10 of the second embodiment, the heat treatment method for a wafer according to the present invention can be performed similarly to the horizontal diffusion furnace 1 of the first embodiment. Can always be stable, and the wafer 30
The wafer 30 can be uniformly heat-treated in the plane. Therefore, the horizontal diffusion furnace 10 of the second embodiment can also improve the uniformity of ρ _{S in} the wafer surface and the film thickness distribution in the wafer surface, thereby improving the semiconductor device manufacturing yield. Can be.

In the first and second embodiments, the apparatus of the present invention is applied to a horizontal diffusion furnace. However, the apparatus of the present invention can be applied to various heat treatment apparatuses for manufacturing semiconductor devices. is there.

[0025]

As described above, according to the wafer heat treatment apparatus of the present invention, after the process gas is preheated to around the heating temperature in the chamber by the heating section provided in the introduction path of the process gas, the inside of the chamber is heated. Can be introduced. Therefore, even when the process gas is introduced into the chamber during the heat treatment and the gas is exhausted, the temperature in the chamber is always stable, and the wafer can be uniformly heat-treated in the wafer surface. Further, according to the wafer heat treatment method according to the present invention, since the process gas is preliminarily heated to a temperature near the heating temperature in the chamber, the temperature in the chamber can always be stabilized, so that the wafer surface can be heated in Can uniformly heat-treat the wafer.
Therefore, according to the wafer heat treatment apparatus and method thereof according to the present invention, it is possible to improve the uniformity of ρ _{S in} the wafer surface and the film thickness distribution in the wafer surface, thereby improving the semiconductor device manufacturing yield. Can be done.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a wafer heat treatment apparatus according to the present invention.

FIG. 2 is a schematic configuration diagram showing a second embodiment of the wafer heat treatment apparatus according to the present invention.

FIG. 3 is a schematic configuration diagram illustrating an example of a conventional device.

[Explanation of symbols]

1, 10 horizontal diffusion furnace 2 furnace core tube 8 preheating tube 11 heating unit

Claims (4)

[Claims] An apparatus for heating a chamber while introducing a process gas into a chamber and heat-treating a wafer transferred into the chamber, wherein the process gas is introduced into a passage for introducing the process gas. A wafer heat treatment apparatus, wherein a heating unit for preheating is provided. 2. The wafer heat treatment apparatus according to claim 1, wherein the heating unit is provided in the chamber. 3. The process gas introduction pipe is connected to the chamber, and the heating unit extends from an end of the introduction pipe connected to the chamber and is spirally provided in the chamber. 3. The wafer heat treatment apparatus according to claim 2, comprising a gas preheating tube. 4. A method of heating the inside of a chamber while introducing a process gas into the chamber, and heat-treating the wafer transferred into the chamber, wherein the process gas is heated in advance in the chamber. A method for heat-treating a wafer, comprising preheating to a temperature in the vicinity, and then introducing a preheated process gas into the chamber.