JPH0997765A - Substrate processing equipment - Google Patents

Abstract

(57) Abstract: Provided is a substrate processing apparatus which makes a substrate temperature uniform. A substrate (S) is placed on a substrate holder (20) arranged in a processing container (1) and supported by a shaft (22), and
In a substrate processing apparatus that holds a substrate S at a predetermined temperature by a heating unit while introducing a gas into the processing container 1 and performs a predetermined process on the substrate S, the heating unit heats the substrate S via a substrate holder 20. And a second heater 29b for heating the shaft 22 to make the substrate temperature uniform from the central portion to the peripheral portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate processing apparatus suitable for forming a thin film on the surface of a substrate such as a semiconductor wafer or for etching a thin film formed on the surface of the substrate. Regarding

[0002]

As is well known, there are several methods for forming a thin film on the surface of a substrate such as a semiconductor wafer. The vapor phase growth method is one of them. The vapor phase growth method uses a chemical reaction of a raw material gas at a high temperature, and has various advantages such as obtaining various kinds of films with strong adhesion strength and relatively easy film thickness control. . As a substrate processing apparatus for actually forming a thin film on the surface of a substrate, a batch type apparatus for simultaneously forming a film on the surfaces of a plurality of substrates is widely used.

However, in recent years, the diameter of semiconductor wafers, which are substrates, has increased, and it has become difficult to ensure uniformity of film formation within a wafer surface or between wafers in a batch type apparatus. For this reason, in the field of semiconductor device manufacturing, there is a tendency to use a single-wafer type apparatus for forming a film on a semiconductor wafer one by one.

In the single-wafer type apparatus, it is necessary to increase the film forming speed in order to improve the throughput. As a means for increasing the film forming speed, a method of increasing the film forming temperature and forming the film while rotating the substrate is considered. That is, the gas in the vicinity of the surface of the substrate can be delivered by centrifugal force by rotating the substrate, and the thickness of the boundary layer can be reduced by this delivery. As a result, the diffusion of the source gas can be facilitated with respect to the high temperature substrate, and as a result, the film formation rate can be increased. Such an effect is also effective when etching the thin film formed on the surface of the substrate. That is, since the diffusion rate of the etching gas with respect to the high temperature substrate can be increased, the time required for etching can be shortened.

By the way, in the substrate processing apparatus in which the substrate is rotated during the film forming process or the etching process as described above, the substrate holder arranged in the processing container is rotatably supported by some means, It is necessary to apply a rotational driving force to this. As a most general method for achieving this, it is conceivable to directly connect the rotating shaft to the substrate holder, support the rotating shaft with a bearing, and apply a rotational force to the rotating shaft with a motor.

However, while the substrate mounted on the substrate holder is being rotated, the surface temperature of the substrate is controlled to, for example, 60 by the heater for heating arranged on the side opposite to the substrate mounting surface of the substrate holder.
It is necessary to keep it uniformly at about 0 to 900 ° C. The uniformity of the substrate temperature is ± 0..0 at the substrate surface temperature of 600 to 900 ° C. in consideration of the performance of the manufactured semiconductor device.
It must be held uniformly within the range of 1 to 3 ° C.
This is because if the temperature of the substrate surface becomes non-uniform, the thickness of the grown thin film formed by treating the substrate surface will vary, and the various performances of the substrate will not be obtained.

The heating of the substrate is performed by radiant heat of the heater for heating arranged under the substrate holder and by heat conduction through the gas existing between the substrate, the substrate holder and the heater for heating. The heat conduction of the gas is performed in this way because natural convection is unlikely to occur because the distance between the substrate, the substrate holder, and the heater for heating is extremely small.

However, in the conventional substrate processing apparatus, heat escapes through the rotating shaft connected to the substrate holder, and the temperature of the substrate holder is likely to drop at the central portion where the rotating shaft of the substrate holder is connected. In particular, when the bearing supporting the rotary shaft becomes hot, stable rotation cannot be ensured. Therefore, when the structure for protecting the bearing part is adopted by forcibly cooling the rotary shaft and cooling it to about 100 ° C. or less, The amount of heat that escapes from the substrate holder via this rotating shaft increases. Due to such an influence, the temperature of the substrate is lower in the central portion than in the outer peripheral portion, and it is difficult to make the temperature distribution of the substrate uniform.

When processing is performed with the substrate having a temperature distribution, for example, in the case of film forming processing, the thickness of the thin film becomes non-uniform and various performances as a substrate cannot be obtained. Had.

[0010]

As described above, in the conventional substrate processing apparatus, heat escapes through the rotating shaft connected to the substrate holder, so that the temperature of the substrate becomes lower in the central portion than in the outer peripheral portion. However, it is difficult to make the temperature distribution of the substrate uniform, the processing state of the substrate cannot be made uniform, and various performances as the substrate cannot be satisfied.

The present invention has been made in order to solve the above problems, and provides a substrate processing apparatus capable of uniformizing the temperature of the substrate to make the processing state of the substrate uniform and stably exhibiting various performances as the substrate. The purpose is to provide.

[0012]

According to the present invention, a substrate is placed on a substrate holder arranged in a processing container and supported by a shaft, and a heating means for heating the substrate while introducing gas into the processing container. In the substrate processing apparatus which holds the substrate at a predetermined temperature and performs a predetermined process on the substrate, the heating unit includes:
First for heating the substrate via the substrate holder
And a second heating means for heating the vicinity of the connecting portion between the substrate holder and the shaft.

Further, the second heating means is arranged so as to heat the vicinity of the connecting portion between the substrate holder and the shaft. Further, it is characterized in that the shaft is divided into a plurality of parts in the axial direction.

Further, the substrate processing apparatus of the present invention includes a processing container, a substrate holder arranged in the processing container for holding a substrate, a rotary shaft connected to the substrate holder, and the rotary shaft being rotatable. Bearing means for supporting the rotating shaft, driving means for applying a rotational driving force to the rotating shaft, first heating means for heating the substrate via the substrate holder, and a vicinity of a connecting portion between the rotating shaft and the substrate holder. And a second heating means for heating.

In other words, by providing a shaft heater for heating the shaft portion connected to the substrate holder in the vicinity of the shaft portion connected to the substrate holder, a heater for heating the substrate via the substrate holder is provided. Is configured to be uniform from the central portion to the peripheral portion.

Further, by dividing the shaft portion to which the substrate holder is connected into a plurality of portions in the axial direction, it is possible to suppress the heat escaping through the shaft and to prevent the temperature from decreasing in the central portion of the substrate. There is.

With such a structure, by providing the second heating means (axial heater), since there is no heating means in the lower part of the shaft portion of the conventional substrate holder, insufficient heating of the central portion of the substrate or It is possible to solve the problem that the temperature of the central portion of the substrate lowers with respect to the peripheral portion of the substrate due to the escape of heat through the shaft. That is, the temperature of the substrate can be made uniform by compensating for insufficient heating of the central portion of the substrate and heat escaping through the shaft by the second heating means (axial heater).

Also, by disposing the second heating means (shaft heater) around the shaft as close as possible to the connecting portion between the substrate holder and the shaft, heat escape through the shaft can be minimized. It is possible (the bearing means is vulnerable to heat, so it is necessary to cool it to around room temperature, and it is important to prevent heat from entering from the shaft as much as possible). Therefore, the loss of the heating means can be reduced and the temperature of the substrate can be made uniform.

Further, by dividing the shaft connected to the substrate holder in the axial direction, it is possible to reduce the amount of heat escaping through the shaft, thereby reducing the loss of the heating means and reducing the substrate temperature. Can be made uniform.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic sectional view of a substrate processing apparatus according to an embodiment of the present invention, and an example in which the present invention is applied to a single wafer type substrate processing apparatus.

A schematic overall structure will be described with reference to FIG. In the figure, 1 indicates a processing container. Although the processing container 1 is actually composed of a combination of several parts, it is shown here to be integrally formed for simplification of the drawing.

A processing chamber 2 is formed above the inside of the processing container 1, and a housing space 3 for housing a magnetic bearing 34 and a motor 35 as a rotary drive mechanism, which will be described later, is formed below the processing chamber 2.

The upper wall 11 of the processing chamber 2 is formed of a transparent member such as a quartz plate. Then, a radiation thermometer or the like (not shown) is arranged above the upper wall 11. Upper wall 11 in processing chamber 2
A rectifying plate 12 made of a heat-resistant transparent member such as quartz is arranged at a position facing to. An annular partition plate 13 is arranged on the peripheral edge of the upper surface of the organizing plate 12, and the partition plate 13 divides the space between the straightening plate 12 and the upper wall 11 into a source gas supply chamber 14 and a purge gas supply chamber 15. ing. The source gas supply chamber 14 is selectively connected to a source gas supply source (not shown) via a source gas introduction port 16, and the purge gas supply chamber 15 is selectively connected to a purge gas supply source (not shown) via a purge gas introduction port 17. To be done.

At the upper position on the side wall of the processing chamber 2, a carry-in port 1 for loading / unloading a substrate S to be processed, which will be described later, into / from the processing chamber 2.
8 are provided. The carry-in port 18 is closed by a valve (not shown) except during the period when the substrate S to be processed is taken in and out. At the lower position on the side wall of the processing chamber 2, the processing chamber 2
Exhaust ports 19 for discharging the raw material gas and the purge gas that have passed through are formed at a plurality of positions in the circumferential direction.

A substrate holder 20 for holding the substrate S to be processed is arranged at a position above the center of the processing chamber 2. The substrate holder 20 is made of a carbon-based material in order to suppress the gas generation amount and to withstand a high temperature atmosphere and a corrosive atmosphere. In this example,
The substrate holder 20 includes a substrate holder main body 21 and the main body 2
It is formed by a shaft portion 22 extending downward from a central portion of the lower surface of the cylindrical member 1 in a predetermined length and a flange portion 23 integrally formed at a lower end of the shaft portion 22. The flange portion 23 is connected to the upper end portion of the rotary shaft 25 via the screw 24. As can be seen from this structure, the shaft portion 22 and the flange portion 23 form a part of the rotary shaft 25.

The rotary shaft 25 is formed of stainless steel or the like, and is actually composed of a combination of several parts, but here it is formed integrally for the sake of simplification of the drawing. Is shown in. The rotating shaft 25 is formed in a hollow shape, and at the connecting portion with the flange portion 23,
A hollow large-diameter portion 26 having a diameter larger than that of the shaft portion 22, for example, an axial length of 25 mm, an inner diameter of 28 mm, and a peripheral wall thickness of 2 mm is formed. The lower end of the rotary shaft 25 extends to the accommodation space 3.

A heat shield cylinder 27 is arranged around the substrate holder 20, and the heat shield cylinder 27 is fixed to the side wall of the processing chamber 2 via a support member 28. A first electric heater 29a serving as a heating source is arranged below the substrate holder 20 so as to be close to the substrate holder 20. This first
The electric heater 29a is fixed to the side wall of the processing chamber 2 by a support member 30 which also serves as a power supply path. The power supply line to the first electric heater 29a is guided outside the processing chamber 2 in an insulated state. A heat shield plate 31 is arranged between the first electric heater 29 and the flange portion 23.

A second electric heater 29 for heating the shaft portion 22 is provided around the shaft portion 22 forming a part of the rotary shaft 25.
b (axis heater) is arranged. The second electric heater 29b also has a support member 30 that also serves as a power supply path, and thus the processing chamber 2
Is fixed to the side wall of the first electric heater 29a (not shown in FIG. 1 because it is supported by the support member 30 with a phase shifted from that of the first electric heater 29a), and the power supply line to the second electric heater 29b is in an insulated state. It is guided to the outside of the processing chamber 2. The second electric heater 29b is preferably arranged near the connecting portion between the substrate holder 20 and the shaft portion 22, and if the vicinity of the connecting portion between the substrate holder 20 and the shaft portion 22 is heated, the second electric heater 29b is mediated by the shaft portion 22. Therefore, the amount of heat transferred to the magnetic bearing 34 can be increased.

Around the hollow large-diameter portion 26 formed on the rotary shaft 25, a cooling liquid flow path 32 is arranged so as to face the hollow large-diameter portion 26 with a minute gap A of about 1 mm.
Cooling water at a temperature of about 25 ° C. is introduced into the cooling liquid flow path 32 through the inlet 33 and is discharged through a discharge port (not shown).

A so-called bottom wall of the processing chamber 2 is provided with a purge gas introduction port 55 for flowing a purge gas into a minute gap A formed between the large-diameter hollow portion 26 and the cooling liquid passage 32. A gas having a high thermal conductivity such as hydrogen, helium, or neon is supplied through the inlet 55.

On the other hand, in the housing space 3, a rotational force is applied to the rotary shaft 25 in a non-contact manner with respect to the magnetic bearing 34 which realizes a non-contact bearing of the rotary shaft 25 with the elements provided on the rotary shaft 25. The motor 35 is arranged.

The magnetic bearing 34 is a radial bearing 36, 37.
And a thrust bearing 38, which is a 5-axis control type. The radial bearings 36, 37 are fixed to the magnetic ring 39 mounted on the outer circumference of the rotary shaft 25 and four magnetic poles 4 at equal intervals in the circumferential direction.
It is composed of a fixed yoke 41 provided with 0 and a control coil 42 attached to each magnetic pole 40.

The thrust bearing 38 is provided with a flange portion 43 provided on the rotary shaft 25, annular magnetic plates 44 and 45 fixed to the upper and lower surfaces of the flange portion 43, and facing the magnetic plates 44 and 45. Fixed yoke with U-shaped cross section fixed to
7 and control coils 48 and 49 mounted on the fixed yokes 46 and 47.

When a displacement signal detected by a sensor (not shown) is input to the radial bearings 36, 37 and the thrust bearing 38, currents of the respective control coils 42, 48, 49 are controlled by a control device (not shown), whereby the radial direction is controlled. In both the thrust and thrust directions, a completely non-contact bearing is realized. Since the control method is publicly known, detailed description will be omitted.

A purge gas inlet 50 for flowing a purge gas such as hydrogen, helium, neon or the like into the accommodation space 3 is formed in the lower wall of the accommodation space 3 so as to push out the process gas which tries to enter the accommodation space 3. There is.

In FIG. 1, reference numeral 51 is inserted into the rotary shaft 25 and the shaft portion 22 of the substrate holder 20, and is inserted into the substrate holder 20 (to be processed) without contacting them to the vicinity of the base end of the shaft portion 22. A thermocouple used for measuring the temperature of the substrate S),
Reference numeral 53 denotes a touchdown bearing that temporarily supports the rotating portion while the magnetic bearing 34 is not operating.

Further, in this example, a purge gas inlet 55 is provided to allow a sufficient amount of purge gas to flow in the minute gap A between the large hollow diameter portion 26 and the cooling liquid flow path 32. Then, an example of use of the substrate processing apparatus configured in this way, a case where a semiconductor wafer is used as the substrate S to be processed and a thin film of silicon is vapor-phase grown on this semiconductor wafer will be described.

First, cooling water is continuously supplied to the cooling liquid flow path 32 as indicated by the solid line arrow in FIG. Further, the magnetic bearing 34 is operated to support the rotating portion in a completely non-contact manner. Next, hydrogen gas is continuously flown into the processing chamber 2 through the gas supply ports 16 and 17, and hydrogen as a purge gas is continuously passed through the purge gas introduction ports 50 and 55 as shown by a broken line arrow in the figure. It is supplied so that the pressure in the processing chamber 2 becomes a predetermined value.

Next, the motor 35 is driven to drive the substrate holder 2
0 (substrate S to be processed) at a predetermined rotation speed (hundreds to tens of thousands of rp)
m), followed by the first and second electric heaters 2
9a and 29b are biased to control the substrate holder 20 (substrate S to be processed) to a predetermined temperature. The temperature is measured by the thermocouple 51 or a radiation thermometer (not shown).

In this state, for example, silane gas and hydrogen gas are supplied to the gas supply port 16 to start thin film growth on the surface of the substrate S to be processed. For comparison with the temperature distribution of the silicon wafer when polysilicon is formed on the surface of the silicon wafer using the apparatus shown in FIG. 1, the conventional substrate processing apparatus, that is, the second electric heater 29b (axis heater)
FIG. 2 shows the temperature distribution when only the first electric heater 29a is used without providing the above.

That is, FIG. 2 shows temperature distribution data of the substrates S to be processed both with and without the second electric heater 29b (axial heater) according to the present invention. The diameter distribution of the substrate S to be processed is 200 mm, and the temperature distribution after 1 minute and after 3 minutes is shown as an example (the steady temperature achievement time depends on the input method of the heater). After the substrate S to be processed is mounted on the substrate holder 20,
When a thin film is grown on the substrate S to be processed after about 3 minutes have passed, the result of FIG.
It can be understood that a temperature difference of about 20 ° C. occurs in the central portion of the substrate S to be processed depending on the presence or absence of the (axial heater). That is, in the case where the second electric heater 29b (axial heater) is provided, after 3 minutes, the substrate surface temperature is made uniform from the central portion to the peripheral portion of the substrate S to be processed.
When the second electric heater 29b (axial heater) is not used, the temperature of the central portion of the substrate S to be processed is lower by about 20 ° C. than the peripheral portion even after 3 minutes, and the temperature distribution becomes uneven. Understand that

As is clear from this result, the presence or absence of the second electric heater 29b (axial heater) of the present invention greatly affects the productivity of the substrate S to be processed, and the second electric heater 29b.
Without the (axial heater), it takes a long time for the temperature of the substrate S to be processed to reach a steady state, and the temperature distribution becomes non-uniform, which greatly affects the thickness of the grown thin film. However, as shown in the present invention, by using the second electric heater 29b (axial heater), the time until the temperature of the substrate S to be processed becomes steady can be shortened, and the temperature distribution of the substrate S to be processed can be further reduced. It becomes easy to make the whole uniform from the central portion to the peripheral portion.

Although not shown, the second electric heater 29b (shaft heater) is installed as close to the connecting portion between the substrate holder 20 and the shaft portion 22 as possible, so that the bearing is supported via the rotary shaft 25. It is possible to minimize the escape of heat to the part 34 (rotating device part). (Since the rotating device part is vulnerable to heat, it is necessary to cool it to around room temperature, so that heat is not transmitted from the rotating shaft as much as possible. Is required). Therefore, the loss of the electric heater can be reduced, and the temperature of the substrate S to be processed can be made uniform while keeping the temperature of the rotating device section low.

Next, FIG. 3 shows an experimental result when the input of the second electric heater 29b (axial heater) is changed. The input of the first electric heater 29a is constant, and only the second electric heater 29b (axial heater) shows the rated input and three experimental results of 0.5 times and 1.5 times the rated input. As described above, it is understood that the temperature of the central portion of the substrate S to be processed can be freely controlled and the time required to reach a steady state can be shortened by variously controlling the input of the second electric heater 29b (axial heater). it can.

FIGS. 4 and 5 are enlarged views of the rotary shaft portion to show an example in which the shaft portion 22 which is a part of the rotary shaft 25 connected to the substrate holder 20 is divided. FIG. 4 shows that the shaft portion 22 is fitted into the shaft portion 22 by dividing the shaft portion 22 into two parts.
It is an example fixed with.

Further, FIGS. 5A and 5B show an example in which the shaft portion 22 is similarly divided into two in the axial direction, the divided surface is formed in an uneven shape, and fixed by fitting. By thus dividing the shaft portion 22 connected to the substrate holder 20 in the axial direction and comprising a plurality of members, the amount of heat transferred to the bearing portion (rotating device portion) via the shaft portion 22 is reduced. It is possible. Therefore, the loss of the electric heater can be further reduced, and the temperature of the substrate S to be processed can be made uniform while keeping the temperature of the rotating device unit low.

The present invention can be implemented without being limited to the above embodiment. For example, magnetic bearing 3
The number of control axes of 4 is not limited to five, and may be three or one.
Further, the present invention can be applied to an apparatus using a type of bearing other than a magnetic bearing, such as a normal ball bearing, which comes into contact with and supports a rotating shaft.

The present invention can also be applied to a substrate processing apparatus of a type that does not have a cooling means for cooling the rotary shaft 25. Furthermore, although the apparatus for rotating the substrate holder has been described in the above description, the present invention can also be applied to a substrate processing apparatus that performs a predetermined process on the substrate S to be processed without rotating the substrate holder. Further, as the substrate processing apparatus, the example in which the film is formed on the surface of the substrate S to be processed is shown, but the present invention can be applied to the apparatus for performing the etching process as described above.

[0049]

According to the present invention, it is possible to provide a substrate processing apparatus capable of uniformly maintaining the temperature of the substrate from the central portion to the peripheral portion and performing processing satisfying various performances as the substrate.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a substrate processing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing substrate temperature distribution data of a substrate processing apparatus according to the present invention and a comparative example.

FIG. 3 is a diagram showing substrate temperature distribution data when a heater according to the present invention is provided.

FIG. 4 is a schematic diagram showing an example of a shape obtained by dividing a shaft portion according to the present invention.

FIG. 5 is a schematic view showing another example of the shape in which the shaft portion according to the present invention is divided.

[Explanation of symbols]

 S substrate to be processed (substrate) 1 processing container 2 processing chamber 3 accommodating container 12 straightening plate 14 raw material gas supply chamber 15 purge gas supply chamber 16 raw material gas introduction port 17 purge gas introduction port 18 carry-in / out port for processing substrate 19 exhaust port 20 Substrate holder 25 Rotating shaft 26 Large hollow portion 29a First electric heater 29b Second electric heater 32 Cooling liquid flow path 33 Cooling liquid inlet 34 Magnetic bearing 35 Motor 36, 37 Radial bearing

Claims (4)

[Claims] 1. A substrate is placed on a substrate holder arranged in a processing container and supported by a shaft, and the substrate is held at a predetermined temperature by a heating means while introducing gas into the processing container. In a substrate processing apparatus for performing a predetermined process on a substrate, the heating means includes a first heating means for heating the substrate via the substrate holder and a second heating means for heating the shaft.
And a heating means for the substrate processing apparatus. 2. A processing container, a substrate holder arranged in the processing container for holding a substrate, a rotary shaft connected to the substrate holder, and bearing means for rotatably supporting the rotary shaft, Driving means for applying a rotational driving force to the rotation shaft, first heating means for heating the substrate via the substrate holder, and second heating means for heating the vicinity of the connecting portion between the rotation shaft and the substrate holder. And a substrate processing apparatus. 3. The substrate processing apparatus according to claim 1, wherein the second heating means is arranged so as to heat the vicinity of a connecting portion between the substrate holder and the shaft. 4. The substrate processing apparatus according to claim 1, wherein the shaft is divided into a plurality of parts in the axial direction.