JP2001308085A - Heat-treating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a high in-plane uniformity of the film thickness for forming, e.g. a film on a wafer by carrying many wafers mounted like shelves on a wafer boat into a reactor tube, heating the wafers using a heater surrounding the reactor tube, and feeding a processing gas. SOLUTION: A heater is divided into a plurality of elements, so as to divide a heat treating atmosphere in a reactor tube 1 into a plurality of regions to share the temperature control at each divided region. After introducing wafers into the reactor tube, each region is heated up to a first processing temperature, then it is transferred up to a second processing temperature corresponding to each region, and a processing gas is introduced into the reactor tube to form, e.g. a film on the wafer in this temperature transfer step. The first and second processing temperatures are set for each region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat treatment method for performing heat treatment on a substrate such as a semiconductor wafer.

[0002]

2. Description of the Related Art A CVD (Chemical Vapor Depositio) is one of the film forming processes as a semiconductor device manufacturing process.
There is a process called n). In this method, a processing gas is introduced into a reaction tube, and a film is formed on a surface of a semiconductor wafer (hereinafter, referred to as a “wafer”) by a chemical vapor reaction. As one of apparatuses for performing such a film forming process in batch, there is a vertical heat treatment apparatus. The apparatus includes a vertical reaction tube provided on a cylindrical manifold, a heater provided to surround the reaction tube, a gas introduction tube protruding through the manifold, and An exhaust pipe connected to the manifold is provided. In such an apparatus, a large number of wafers are held in a shelf by a holder called a wafer boat, and an opening at the lower end of the manifold is provided. , And carried into a reaction tube to perform a film forming process.

Specifically, for example, when a silicon nitride film as an interlayer insulating film is formed, the wafer is heated to a processing temperature of, for example, 760 ° C. in a vacuum atmosphere of about 0.1 to 1 Torr, and this heated atmosphere is maintained. In this state, ammonia (NH3) gas, which is a film forming gas, and dichlorosilane (SiH2)
Cl2) gas is introduced to form a film.

[0004]

When a wafer is formed under the above-mentioned conditions using the above-described apparatus, the film thickness at the central portion of the wafer tends to be smaller than that at the peripheral portion. The reason is considered as follows. In other words, in the above-described vertical heat treatment apparatus called a batch furnace, in the process of raising the temperature of the wafer to the processing temperature, the wafer is heated by a heater located on the peripheral side of the wafer, and the unit area per unit area in the peripheral portion of the wafer is increased. Since the heat absorption amount of the wafer becomes larger than that of the central portion, the temperature rise rate of the peripheral portion of the wafer becomes faster than that of the central portion, and the temperature of the peripheral portion becomes higher than that of the central portion. Further, in the above-described apparatus, the film formation gas is introduced into the reaction tube by the gas introduction tube, and the film formation gas is supplied to the wafer held in the wafer boat from the peripheral side of the wafer. The gas concentration is higher at the periphery of the wafer than at the center.

As described above, due to the temperature difference and the concentration difference of the film forming gas generated between the peripheral portion and the central portion of the wafer, the peripheral portion of the wafer having the higher temperature and the higher concentration of the film forming gas is higher than the central portion. It is presumed that the film formation reaction was accelerated, and the film thickness at the central portion of the wafer became thinner than the peripheral portion, and the in-plane uniformity of the film thickness was deteriorated. Such in-plane uniformity of film thickness is 300 m
When a large-diameter wafer such as an m-wafer or a thick film having a film thickness of 70 nm or more is formed, the problem becomes worse, which is a problem.

The present invention has been made under such circumstances, and an object of the present invention is to provide a heat treatment method capable of performing treatment with high in-plane uniformity when heat treating a substrate.

[0007]

SUMMARY OF THE INVENTION The present invention provides a heat treatment method in which a substrate is placed in each zone in a reaction vessel in which a heat treatment atmosphere is divided into a plurality of zones, and a treatment gas is introduced into the reaction vessel to perform heat treatment. The steps of: loading a plurality of substrates into a reaction vessel; heating each zone in the reaction vessel by a heating unit to raise each zone to a first process temperature corresponding to the zone; For at least one of the plurality of zones, a first of the zones
From the process temperature to a second process temperature corresponding to the zone, and performing a heat treatment on the substrate by introducing a process gas into the reaction vessel during the temperature shift process. Features.

In the present invention, the first process temperatures in, for example, at least two zones of the plurality of zones are set to be different from each other, or the second process temperatures in, for example, at least two zones are set to be different from each other. Is set. In the temperature transition process,
For example, at least one zone is a heating step or a cooling step. In the temperature transition step, the case where the temperature is maintained in at least one zone at the first process temperature is also included in the scope of the present invention.

Further, in the temperature transition step, for example, at least two of the plurality of zones transition from a first process temperature of the zone to a second process temperature corresponding to the zone. The temperature difference between the first process temperature and the second process temperature is
They are set to be different from each other. In the present invention, after the temperature transition step, at least one zone may further include an additional temperature transition step of transitioning from the second process temperature to the first process temperature. The step and the additional temperature transition step may be performed repeatedly.

Here, when the temperature during the process is made constant,
For example, in the case of a film forming process, the film thickness at the peripheral portion becomes larger or smaller than that at the central portion, and the degree may vary depending on the zone in the reaction vessel. On the other hand, in the step of raising the temperature inside the reaction vessel, the amount of heat absorbed per unit area in the peripheral portion of the substrate becomes larger than that in the central portion, so that the temperature of the peripheral portion becomes higher than that in the central portion, and conversely, in the temperature decreasing step, Since the amount of heat radiation per unit area at the peripheral edge of is larger than that at the center, the temperature at the peripheral edge is lower than at the center. Therefore, the processing gas is introduced while shifting the temperature, and a temperature distribution is provided in the substrate surface, and the temperature distribution and the film thickness distribution in the surface when the temperature during the process is kept constant influence each other. By doing so, processing with high in-plane uniformity can be performed as a result.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an example of a vertical heat treatment apparatus for carrying out the method of the present invention will be described with reference to FIG. 1 in FIG.
Is a reaction tube having a double tube structure composed of an inner tube 1a and an outer tube 1b made of, for example, quartz, and a metal cylindrical manifold 2 is provided below the reaction tube 1. .

The inner tube 1a has an open upper end and is supported on the inner side of the manifold 2. The upper end of the outer tube 1b is closed, and the lower end is hermetically joined to the upper end of the manifold 3. In this example, the inner tube 1a, the outer tube 1b
And the manifold 2 constitute a reaction vessel.
21 is a base plate.

In the reaction tube 1, for example, as shown in FIG. 2, a large number of wafers W, for example, about 170 substrates, are formed.
Are placed on a wafer boat 11 which is a holder in a horizontal manner at intervals above and below, and the wafer boat 11 has a heat insulating cylinder (heat insulator) 13 on a lid 12. Is held through. The lid 12 is provided with a wafer boat 11.
Is mounted on a boat elevator 14 for loading and unloading into and out of the reaction tube 1, and at the upper limit position, the opening at the lower end of the manifold 2, that is, the reaction tube 1 and the manifold 2. It serves to close the lower end opening of the reaction vessel thus constituted. In FIG. 2, reference numeral 15 denotes a wafer boat 11.
This is a transfer arm for transferring the wafer W to the transfer arm.

A plurality of gas introduction pipes 31 and 32 for supplying a film forming gas (processing gas) and a purge gas to the inside of the inner pipe 1a are provided in the manifold 2 in a circumferential direction. The film formation gas is introduced into the reaction vessel from the respective gas introduction pipes 31 and 32. The gas introduction tubes 31 and 32 are made of, for example, quartz tubes. For example, the gas introduction tube 31 is configured by projecting the quartz tube from the outside of the manifold 2 to the inside thereof and bending the tip thereof upward.
The gas introduction tube 32 is constructed by projecting the quartz tube from the outside to the inside of the manifold 2. These gas introduction pipes 31,
One or more of the pipes 32 share a pipe for introducing nitrogen gas (N2 gas) as a purge gas and a pipe for introducing a film forming gas. Oxygen may be introduced into the inner tube 1a as a processing gas in addition to the film forming gas.

The gas introduction pipes 31, 32 are connected to a gas supply source (not shown) of a film forming gas, for example, SiH2 Cl2 gas and NH3 gas, via opening / closing valves V1, V2, respectively. V2 is controlled by the control unit 5.
The timing of opening and closing is controlled based on a program for introducing a film forming gas during the film forming process which is input in advance, and thereby the timing of introducing the film forming gas is controlled. The manifold 2 has an inner tube 1a.
An exhaust pipe 22 is connected so as to open between the outer tube 1b and the outer tube 1b, and the inside of the reaction vessel is evacuated by a vacuum pump (not shown).

A heater 4 as heating means is provided around the reaction tube 1 so as to surround it. The heater 4 is composed of, for example, a heating resistor, and the control unit 5 controls the temperature based on a temperature profile of a film forming process input in advance. Meanwhile, the heat treatment atmosphere in the reaction tube has a plurality of, for example, three zones (regions) 6 (6a, 6a) from top to bottom.
b, 6c) (meaning that the temperature control area is divided), and the heater 4 also corresponds to these three zones, that is, these three zones 6a, 6b, 6c. Are divided into three heaters 4 (4a, 4b, 4c) so as to respectively perform the temperature control. Although the control unit 5 is shown as a single block in FIG. 1 for convenience, a temperature controller (not shown) is provided for each of the heaters 4a, 4b, and 4c, and these temperature controllers are provided in the zones 6a, 6b, and 6c. Each of the heaters 4 based on a temperature detection signal of a temperature detection unit (not shown) provided corresponding to
a, 4b, 4c.

Next, the heat treatment method of the present invention performed by the above-described apparatus will be described with reference to FIG. 3 by taking a case of forming a silicon nitride film as an example. First, for example, 170 wafers W as objects to be processed are mounted on the wafer boat 11 and the boat elevator 14 is lifted up to, for example, 6 wafers.
The lower end opening of the manifold 2, that is, the wafer loading / unloading port of the reaction vessel, is airtightly sealed by the lid 12 into the reaction tube 1 in a heating atmosphere of 00 ° C. (loading step). Next, the inside of the reaction vessel is evacuated through the exhaust pipe 22 by a vacuum pump (not shown) under a heating atmosphere of, for example, 600 ° C. (stabilization step).

Subsequently, each zone 6a, 6b,
After the temperature of 6c is once heated to a first process temperature, for example, a temperature of about 770 ° C. by the heaters 4a, 4b, and 4c, respectively (first temperature raising step), temperature control is performed based on a predetermined temperature profile. Meanwhile, SiH2 Cl2 gas and NH3 gas are used as film forming gases,
A silicon nitride film is formed on the surface of the wafer W while the pressure is set to 0.25 Torr by introducing the silicon nitride film into the inner tube 1a from the first and second tubes 32 (process step). At this time, the film forming gas is introduced into the inner tube 1a, and the inside of the outer tube 1b is exhausted by the exhaust tube 22, so that the film forming gas spreads into the reaction tube 1 and the wafer mounted on the wafer boat 11 A silicon nitride film is uniformly formed on the surface of W.

Here, the respective zones 6a, 6b, 6c are all subjected to the same temperature control. However, different temperature controls may be performed as described later.

The present invention is characterized in that the temperature of the wafer W is controlled in the process step and the film forming gas is intermittently introduced in accordance with the temperature control. For example, in the process step, each of the zones 6a and 6b is controlled. , 6c between the first process temperature and the second process temperature lower than the first process temperature, specifically, a temperature around 760 ° C., for example, 7
The temperature is controlled so that the temperature rise and the temperature fall are repeated in the range of 50 ° C. to 770 ° C., and a film forming gas is introduced at the time of the temperature fall.

As a specific process, as shown in FIG. 4, for example, each zone 6a, 6b, 6c is heated to a first process temperature by heating with heaters 4a, 4b, 4c. After the temperature is raised to about 770 ° C., a second process temperature lower than the first process temperature, for example, 75
The heating by the heaters 4a, 4b, and 4c is suppressed to about 0 ° C., and the temperature is lowered in, for example, about 23 minutes.
SiH2 Cl2 gas and NH3 gas at 100 scc each
m, at a flow rate of 1000 sccm (steps after the temperature), and then with the introduction of these film forming gases stopped,
The temperature is raised again to about 770 ° C. in about 4 minutes (second
Heating step). Next, while introducing the film forming gas again,
The temperature is lowered to about 750 ° C. in, for example, about 23 minutes.
The temperatures of a, 6b and 6c are raised to about 770 ° C. in about 4 minutes, for example (an additional temperature transition step). Next, while introducing the film forming gas again, each zone 6a, 6b, 6c was heated to 750 ° C.
To about 30 minutes, for example (temperature transition step)
Subsequently, with the introduction of the film forming gas stopped, the temperature of each of the zones 6a, 6b and 6c is raised again to about 770 ° C. in about 4 minutes, for example (an additional temperature transition step). Then, while introducing the film forming gas again, the temperature of each zone 6a, 6b, 6c is lowered to about 750 ° C. in, for example, 23 minutes. That is, in this process, the introduction of the film forming gas is started at the start of the temperature decrease, and the introduction of the film forming gas is stopped at the start of the temperature increase (at the end of the temperature decrease).

In this embodiment, each zone 6a,
The heaters 6b and 6c are heated to a predetermined temperature by the heater 4. The predetermined temperature control in the process step is performed by the control unit 5 based on the temperature profile input to the control unit 5 as described above. And each heater 4a, 4b, 4c
This is performed by controlling the heating temperature. The start and stop of the introduction of the deposition gas are performed by opening and closing the on-off valve V. The opening and closing of the on-off valve V is controlled by the control unit 5 as described above.

After the completion of the formation of the predetermined silicon nitride film, the introduction of the film formation gas is stopped and each zone 6
The temperatures of a, 6b and 6c are lowered to about 600 ° C. (temperature lowering step), and a purge gas such as N 2 gas is discharged from, for example, two of the gas introduction pipes 31 and 32 into which the deposition gas was introduced during the deposition. And the pressure inside the reaction vessel is returned to normal pressure. Then, the boat elevator 14 is lowered to open the carry-in / out port at the lower end of the reaction vessel, and the wafer boat 11 is carried out of the reaction vessel (unloading step).

According to such an embodiment, the surface temperature of the wafer W is controlled in the process step so that the temperature is repeatedly increased and decreased, and the film forming gas is introduced at the time of the temperature decrease. In-plane uniformity of the thickness of the silicon nitride film to be formed can be improved.

That is, as described above, in the step of raising the temperature of the wafer W, the amount of heat absorbed per unit area at the peripheral portion of the wafer is larger than that at the central portion, so that the temperature at the peripheral portion of the wafer is higher than that at the central portion. Become. Here, since the growth rate of the film increases as the temperature during film formation increases, if the film is formed by immediately introducing the film formation gas after the temperature of the wafer W is increased to a predetermined temperature, the film formation described above is performed. When combined with the concentration distribution of the film gas in the wafer surface, for example, as shown in FIG. 5, the film thickness at the central portion of the wafer is smaller than the peripheral portion. Here, FIG. 5 shows each of the zones 6a, 6b, 6c in the vertical heat treatment apparatus.
Is heated to a predetermined temperature, for example, 760 ° C., and a film forming gas is immediately introduced to form a silicon nitride film in a state where the temperature of the wafer W is maintained at the aforementioned temperature. FIG. 4 is a characteristic diagram illustrating a film thickness distribution of a silicon film in a wafer surface.

On the other hand, when the temperature of the wafer W is lowered, the amount of heat radiation per unit area at the peripheral portion of the wafer is larger than that at the central portion, so that the temperature of the peripheral portion of the wafer decreases at a higher rate than the central portion. As shown in 6 (temperature distribution in the wafer surface when the temperature of the wafer W is lowered from about 770 ° C. to about 750 ° C.), the temperature of the peripheral portion is lower than that of the central portion.

Therefore, the temperature of each of the zones 6a, 6b, 6c is raised to the first process temperature, and then lowered to the second process temperature. A temperature distribution of the wafer W in the temperature lowering step in which the temperature of the peripheral portion is lower than that of the central portion of the wafer W;
The film thickness of the film formed as shown in FIG. It is presumed that it becomes almost uniform in. Here, FIG. 7 shows that, in the vertical heat treatment apparatus, after each zone 6a, 6b, 6c is heated to the first process temperature and then cooled to the second process temperature, a film forming gas is introduced. FIG. 4 is a characteristic diagram showing a film thickness distribution in a wafer surface of the formed silicon nitride film when a silicon nitride film is formed.

As described above, in this embodiment, when forming a silicon nitride film, the first process temperature is set to 770.
The second process temperature was set to 750 ° C., and the difference between these temperatures was set to 20 ° C. However, since the film forming temperature affects the film quality of the silicon nitride film, the film forming temperature range is limited. If the difference between the first process temperature and the second process temperature is set to about 40 ° C. or less, there is no problem.

Therefore, it is desirable to repeat the temperature transition step and the additional temperature transition step in a constant film forming temperature range that does not cause any trouble. An in-plane distribution of the film thickness can be obtained. For this reason, the present invention is particularly effective when, for example, a film is formed on a wafer having a diameter of 300 mm, or when a film having a thickness of 70 nm or more is formed. Uniformity can be ensured.

In order to actually confirm the effect of the present invention, 170 8-inch size wafers W were placed on the wafer boat 11.
8 and 9 when a silicon nitride film was formed by the above-described vertical heat treatment apparatus according to the above-described process.
The result shown in FIG. The film forming gas is SiH2 Cl
While controlling the temperature of each zone 6a, 6b, 6c in accordance with the temperature profile shown in FIG. 4 by using 2 gas and NH3 gas, 100 s
m, NH3 gas were introduced at a flow rate of 1000 sccm, respectively, and under a process pressure of 0.25 Torr, 150 nm
A silicon nitride film was formed with the target thickness, and the in-plane distribution of the thickness of the silicon nitride film and the in-plane uniformity of the thickness of the silicon nitride film were measured. A similar experiment was conducted when a silicon nitride film was formed by continuously introducing a film forming gas while maintaining the temperature of the wafer surface at 760 ° C. in the vertical heat treatment apparatus described above. In this case, the flow rate of the film forming gas is as follows: SiH2 Cl2 gas 100 sccm, NH3 gas 1
000 sccm and the process pressure is 0.25 Torr
And

The results are shown in FIGS. 8 and 9, respectively. FIG. 8 shows the degree of variation in the thickness of the silicon nitride film, and FIG. 9 shows the in-plane distribution of the thickness of the silicon nitride film. The case where temperature control was performed is indicated by □, and the case where temperature control is not performed is indicated by ○. The seventh variation, the 46th variation, the 85th variation from the top of the wafer boat 11 are shown in FIG.
The 124th and 163rd wafers W are sampled,
The in-plane uniformity of the film thickness of the silicon nitride film formed on these wafers W was measured by a film thickness measuring device (Ellipsometer).

As a result, when the temperature control is performed, the value of the degree of film thickness variation is lower than when the temperature control is not performed, and the lower the value, the higher the in-plane uniformity. Therefore, it was confirmed that the temperature control was performed during the process step, and the in-plane uniformity of the film thickness of the silicon nitride film formed by introducing the film-forming gas at the time of temperature reduction could be improved.

The in-plane distribution of the thickness of the silicon nitride film shown in FIG. 9 is obtained by sampling the 124th wafer W from above on the wafer boat 11, and as shown in the plan view of the wafer W in FIG. The thickness of the silicon nitride film was measured at five positions (A, B, C, D, and E) in the radial direction on the diameter of the wafer W. Here, C is the center of the wafer W, A and E are the wafers W
Are located 5 mm inside from the outer edge of the wafer W, and B and D are located 52.5 mm inside from the outer edge of the wafer W.

As a result, when the temperature control is not performed, the thickness of the silicon nitride film is 2.
While it was recognized that the thickness was reduced by about 91 to 3.48 nm, when the temperature was controlled, it was recognized that the thickness of the silicon nitride film was almost constant with a variation of about 0.36 nm, It was confirmed that by controlling the temperature during the process step and introducing the film forming gas during the temperature decrease, the in-plane uniformity of the thickness of the formed silicon nitride film can be improved.

In the above, according to the present invention, each zone 6a,
A first temperature raising step of raising the temperature of 6b and 6c to the first process temperature is performed, and then a temperature lowering step of forming a film by introducing a film forming gas while lowering the temperature to the second process temperature may be performed. It is not necessary to repeat the temperature transition step and the additional temperature transition step, but if the temperature transition step, the additional temperature transition step, and the temperature lowering step are repeated, higher film thickness uniformity can be ensured. it can.

Further, the present invention can be applied not only to the formation of a silicon nitride film but also to the formation of a polysilicon film, a silicon oxide film by TEOS, an HTO (High Temperature Oxide) film, and the like. Further, the present invention can be applied to formation of an oxide film such as dry oxidation, wet oxidation, and HCl oxidation other than the CVD film formation process.

In the above embodiment, the reaction tube 1
Although the same temperature control is performed on each of the zones 6a, 6b, 6c in the above, the different temperature control may be performed on each of the zones 6a, 6b, 6c by the heaters 4a, 4b, 4c. Good.

Next, another embodiment of the present invention will be described with reference to FIG.
1 will be described. FIG. 11 shows S as a film forming gas.
Each zone 6a, 6a when forming a silicon nitride film on the surface of the wafer W using iH2 Cl2 gas and NH3 gas.
It is a figure which shows the relationship between time and temperature in b and 6c. FIG.
As shown in FIG. 1, the first process temperatures assigned to the zones 6a, 6b, 6c are different from each other, and the second process temperatures assigned to the zones 6a, 6b, 6c are different from each other. The profile has been set. For example, the first process temperature and the second process temperature in the upper zone 6a are respectively 76
The temperature is 5 ° C. and 732 ° C., and the first process temperature and the second process temperature in the middle zone 6b are 770 ° C. and 757 ° C., respectively. The first process temperature and the second process temperature in the lower zone 6c are 800 ° C. and 757 ° C., respectively.

In each of the zones 6a, 6b, and 6c, the temperature is first raised to the first process temperature (temperature raising step), and then the temperature shifts to a temperature transition step in which a film forming gas is introduced, and the temperature is lowered to the second process temperature. Is done. In the temperature transition step, the temperatures of all the zones 6a, 6b, and 6c are lowered, and a film forming gas is introduced during the temperature lowering to form a uniform silicon nitride film on the surface of the wafer W. In this case, the second
The temperature may be further increased from the first process temperature to the first process temperature (an additional temperature transition step), and then the temperature may be decreased from the first process temperature to the second process. Further, in the middle zone 6b, when the temperature is constant, the difference in film thickness between the peripheral portion and the central portion of the wafer W is very small, so that the gradient of the temperature change in the temperature transition step (the The difference between the first process temperature and the second process temperature) is considerably smaller than the slope of the temperature change in the upper zone 6a and the lower zone 6b.

When temperature control is performed among the zones 6a, 6b, and 6c as described above, the processing gas rises from below in the reaction vessel, so that the temperature in the upper zone 6a is high. For example, upper zone 6
a is controlled at a relatively low temperature, and the lower zone 6c is controlled at a relatively high temperature. When the temperature is constant, the difference in film thickness between the peripheral portion and the central portion of the wafer W is grasped in advance, and the slope of the temperature change is determined according to the difference in film thickness. Therefore, it is possible to make the silicon nitride film uniform in each wafer W, and to make each zone 6
The uniformity of the silicon nitride film formed on the surface of the wafer W can also be achieved between a, 6b, and 6c.

FIG. 1 shows still another embodiment of the present invention.
This will be described with reference to FIG. FIG. 12 shows TEOS (tetraethoxysilane: Si (C2H5O)) as a film forming gas.
FIG. 4 is a diagram showing a relationship between time and temperature in each zone when a silicon oxide film is formed on the surface of a wafer W using 4). In this method, the heat treatment atmosphere is divided into five zones, and correspondingly, the heater 4 is also divided into five stages, and different temperature control is performed on each zone by the divided heaters. ing. 5 for convenience of explanation
For each zone divided into stages, 6a,
6ab, 6b, 6bc, and 6c are respectively assigned.

Each zone 6a, 6ab, 6b, 6bc, 6
Regarding the first process temperature and the second process temperature c, the first process temperature and the second process temperature of the first zone (uppermost stage) 6a are 699 ° C. and 672 °, respectively.
° C, the first process temperature and the second process temperature in the second zone 6ab are 692 ° C and 674 ° C, respectively, and the first process temperature and the second process temperature in the third zone 6b. Are 685 ° C. and 673 ° C., respectively.
The first process temperature and the second process temperature of the fourth zone 6bc are 675 ° C. and 675 ° C., respectively, and the first process temperature and the second process temperature of the fifth zone 6c are 662 ° C., respectively. And 685 ° C. As described above, in this embodiment, the first process temperature and the second process temperature are set in the respective zones 6a, 6ab, 6b, 6bc,
6c are different from each other.

As shown in FIG.
a, 6ab, 6b, 6bc, and 6c,
Temperature to the process temperature (temperature raising step), and then TE
The process enters a temperature transition step in which the OS is introduced. In this temperature transition step, the temperature is raised from the first process temperature to the second process temperature in the fifth zone 6c, and the fourth zone 6
In bc, the temperature is kept isothermally from the first process temperature to the second process temperature, and the zones 6a, 6ab, 6
In b, the temperature is decreased from the first process temperature to the second process temperature.

In this case, each zone 6a, 6ab, 6b, 6
In bc and 6c, the temperature may be further shifted from the second process temperature to the first process temperature (an additional temperature shift step), and then the temperature may be shifted from the first process temperature to the second process temperature. Good (temperature transition step).
Thereafter, the zones 6a, 6ab, 6b, 6bc, 6c enter a temperature holding step.

Here, in the zone 6c of the fifth stage, which is the lowermost stage, when the temperature control is not performed, the film thickness of the film to be formed tends to be higher in the central portion than in the peripheral portion of the wafer. Therefore, unlike the temperature control in the other zones 6a, 6ab, 6b, 6bc, the temperature is raised in the temperature transition step. In the fourth zone 6bc, the difference in film thickness between the peripheral portion and the central portion of the wafer W is very small when the temperature is constant, so that the temperature is kept constant in the temperature transition step.

As described above, each zone 6a, 6ab, 6b,
By performing different temperature control between 6bc and 6c, that is, by setting appropriate first process temperature and second process temperature according to each zone, the silicon oxide film on each wafer W is made uniform. And zones 6a, 6ab, 6b, 6bc, 6
It is possible to make the silicon oxide film formed on the surface of the wafer W uniform during the interval c.

[0047]

As described above, according to the present invention, in-plane uniformity of a high film thickness can be ensured when forming a film on a substrate.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing an example of a vertical heat treatment apparatus for performing a method of the present invention.

FIG. 2 is a perspective view showing a part of the vertical heat treatment apparatus.

FIG. 3 is a characteristic diagram showing a relationship between temperature and time when a silicon nitride film is formed by the method of the present invention.

FIG. 4 is a characteristic diagram showing a relationship between temperature and time when a silicon nitride film is formed.

FIG. 5 is a characteristic diagram showing a relationship between a thickness of a silicon nitride film and a position on a wafer.

FIG. 6 is a characteristic diagram showing a relationship between a temperature and a position on a wafer.

FIG. 7 is a characteristic diagram showing a relationship between a thickness of a silicon nitride film and a position on a wafer.

FIG. 8 is a characteristic diagram showing the relationship between the in-plane variation of the thickness of the silicon nitride film and the position of the wafer on the wafer boat.

FIG. 9 is a characteristic diagram showing a relationship between a thickness of a silicon nitride film and a position on a wafer.

FIG. 10 is a plan view for explaining sampling locations on a wafer.

FIG. 11 is a characteristic diagram showing a relationship between temperature and time when a silicon nitride film is formed.

FIG. 12 is a characteristic diagram showing a relationship between temperature and time at the time of forming a silicon oxide film.

[Explanation of symbols]

 W Semiconductor wafer 1 Reaction tube 1a Inner tube 1b Outer tube 2 Manifold 3 Gas introduction tube 4 (4a, 4b, 4c) Heater 5 Control unit V Open / close valve

Continued on the front page (72) Inventor Wang Liang 5-6-6 Akasaka, Minato-ku, Tokyo TBS Transmission Center Tokyo Electron Limited (72) Inventor Moyuru Yasuhara 5-6-Akasaka, Minato-ku, Tokyo No. TBS Broadcasting Center Tokyo Electron Limited

Claims (11)

[Claims] 1. A heat treatment method in which a substrate is arranged in each zone in a reaction vessel in which a heat treatment atmosphere is divided into a plurality of zones and a heat treatment is performed by introducing a processing gas into the reaction vessel. And heating each zone in the reaction vessel by a heating unit to raise each zone to a first process temperature corresponding to the zone; and at least one of the plurality of zones. A temperature transition step of transitioning from a first process temperature of the zone to a second process temperature corresponding to the zone, wherein a processing gas is introduced into the reaction vessel during the temperature transition step, A heat treatment method, wherein a heat treatment is performed on the steel sheet. 2. The heat treatment method according to claim 1, wherein the first process temperatures in at least two of the plurality of zones are different from each other. 3. The heat treatment method according to claim 1, wherein the second process temperatures in at least two of the plurality of zones are different from each other. 4. The heat treatment method according to claim 1, wherein in the temperature transition step, at least one zone is heated from a first process temperature to a second process temperature. 5. The heat treatment method according to claim 1, wherein in the temperature transition step, at least one zone is cooled from a first process temperature to a second process temperature. 6. The heat treatment method according to claim 1, wherein in the temperature transition step, the temperature of at least one zone is maintained at the first process temperature. 7. The temperature transition step, wherein at least two of the plurality of zones are the first of the zones.
Wherein the temperature difference between the first process temperature and the second process temperature in these zones is different from each other. 7. The heat treatment method according to any one of 6. 8. The method according to claim 1, further comprising, after the temperature transition step, an additional temperature transition step of transitioning the at least one zone from the second process temperature to the first process temperature. 8. The heat treatment method according to any one of items 7 to 7. 9. A temperature transition step and an additional temperature transition step,
9. The heat treatment method according to claim 8, wherein the heat treatment is performed repeatedly. 10. The heat treatment method according to claim 1, wherein the temperature of each zone is controlled by heating means provided for each zone outside the reaction vessel. 11. The heat treatment method according to claim 1, wherein in the temperature transition step, a processing gas is introduced from a gas introduction pipe provided on a peripheral edge of the reaction vessel.