JPH06120145A - Film forming equipment - Google Patents

Abstract

PURPOSE:To obtain a film forming equipment wherein film formation on the rear of a semiconductor substrate can be prevented, generation of particles can be restrained, purge gas flow rate can be reduced by making the purge gas effectively act, film thickness distribution can be improved, a large amount of purge gas can be made to flow, and correspondence with a process of high gas concentration is possible. CONSTITUTION:The title equipment is provided with a retaining stand 2 for mounting a semiconductor substrate, a heating equipment, and a gaseous raw material gas supplying means for supplying the gaseous raw material. Purge gas Ia-Ic flows out in the outer peripheral direction of the retaining stand. Further the title equipment is provided with mechanism which makes the purge gas flow from the rear, and an exhaust vent of purge gas is installed in the vicinity of the purge gas discharging outlet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus. INDUSTRIAL APPLICABILITY The present invention can be used, for example, as a film forming apparatus for forming various thin films when manufacturing a semiconductor device. For example, it can be embodied as a metal CVD apparatus, and can be particularly suitably embodied as a metal CVD apparatus for burying fine contact holes or for forming heat resistant wiring.

[0002]

2. Description of the Related Art The role of a film forming apparatus used for a semiconductor device or the like has become important, and especially, for example, CVD.
The device is indispensable for making a semiconductor device such as ULSI.

One of the important problems to be solved in the film forming apparatus is suppression of particles. In particular, since a CVD apparatus performs a film forming process, particles are very likely to be generated, which is an important problem.

Among them, metal C, which has poor adhesion to the substrate
VD, especially blanket tungsten CVD, is easily peeled off and particles are easily generated. Similar problems occur with selective tungsten CVD.

However, the above blanket tungsten C
VD is drawing attention as one of the technologies for filling the fine wiring of the 0.35 micron rule or smaller contact holes and through holes with wiring materials in the multi-layer wiring formation process technology of the ULSI of the next generation or later.

The apparatus (cold wall type) shown in FIG. 6 has a structure in which a support table (susceptor) 2 is heated by an IR lamp which is a heating apparatus 1, and the semiconductor substrate (wafer) 3 is heated by the heat. . Details of the susceptor 2 portion of this device are shown in FIGS. In this background art, as shown in FIG. 6, the source gas is supplied from the lower gas supply port 6, uniformly diffused by the gas plunger 71, and reaches the wafer surface. The reached gas reacts on the substrate surface to form a thin film. In the figure, 4 is a quartz glass (quartz) window, 5 is a source gas duct, 7 is a side wall of a chamber, 9 is a crank finger,
12 is a chuck body.

The problem of peeling in the prior art will be described as follows. For example, blanket C
Metal thin film (especially tungsten) formed by VD method
Has poor adhesion to the substrate and is very easy to peel off. Therefore, when forming a metal thin film on the surface of the substrate, an adhesion layer is necessary. In the case of blanket tungsten CVD, a TiN film is often used. However, since the tungsten thin film is peeled off from the substrate portion where the TiN film is not formed, it is basically necessary to take measures to prevent the tungsten thin film from growing.

In the apparatus shown in FIGS. 7 and 8 and FIGS. 9 and 10, the portion where the TiN thin film is not formed,
A purge gas is supplied from the back surface of the susceptor 2 so that the tungsten thin film is not formed on the clip mark portion of the TiN sputtering apparatus or the back surface of the semiconductor substrate. The support base (susceptor) 2 in this example is a graphite susceptor 2a.
And a susceptor 2b such as SUS on the outer circumference.

FIG. 11 shows a graphite susceptor. The hole 10 (passage) formed in the graphite susceptor 2a is for introducing the purge gas into the peripheral portion of the semiconductor substrate. In each figure, 8 is a thermocouple and 81 is a screw.

However, since the direction of the flow of the purge gas is not controlled, there is a problem that (a) the gas flow on the semiconductor substrate is affected and the film thickness distribution is affected. Further, (b) when the film forming rate is increased, the escape must be increased, and there is a problem that turbulence or stagnation occurs.

Further, since the flow rate of the purge gas flowing from between the clamp and the wafer is very small, it is impossible to completely prevent the reaction gas from flowing around to the back surface of the wafer.

Further, in the so-called RDR apparatus as shown in FIGS. 12 and 13, since the reaction gas on the wafer surface is characterized by a laminar flow, a clamp cannot be installed, Further, since it is not possible to flow a large amount of purge gas to the extent that the purge gas does not sneak into the back surface, prevention of sneaking into the back surface is an issue. In each figure, II is a gas inlet, and Ia to Ic are flows of purge gas.

[0013]

It is a first object of the present invention to prevent film formation on the back surface of a semiconductor substrate, to suppress the generation of particles, and to reduce the purge gas flow rate because the purge gas from the back surface acts effectively. (EN) A film forming apparatus capable of improving the film thickness distribution without affecting the film forming reaction on a semiconductor substrate by reducing the purge flow rate.

A second object of the present invention is to provide a film forming apparatus capable of allowing a large amount of purge gas to flow, and capable of supporting a medium pressure (for example, 10 kPa) process having a high gas concentration.

[0015]

According to a first aspect of the present invention, there is provided a support base on which a semiconductor substrate is mounted, a heating device for heating the semiconductor substrate via the support base, and the semiconductor. A film forming apparatus having a source gas supply means for supplying a source gas for growing a thin film on a substrate, wherein the purge gas is configured to flow out in the outer peripheral direction of the support table. Thus, the above object is achieved.

According to a second aspect of the present application, a support base on which a semiconductor substrate is placed, a heating device for heating the semiconductor substrate via the support base, and a thin film grown on the semiconductor substrate. In a film forming apparatus having a source gas supply unit for supplying a source gas for supplying the source gas, the supporting base is fixed to the side wall of the reaction chamber at the contact portion that is at least a portion in contact with the semiconductor substrate and the outer periphery of the supporting base. The film forming apparatus is characterized in that a gas direction control mechanism for diffusing the purge gas in the outer peripheral direction is provided in a contact portion that is in contact with the semiconductor substrate. Thus, the above object is achieved.

The invention according to claim 3 of the present application is the film forming apparatus according to claim 1 or 2, further comprising a mechanism for introducing a purge gas between both parts of the divided support base. This achieves the above-mentioned object.

According to the invention of claim 4 of the present application, a material having good heat conduction is used as a material of the contact portion of the supporting base, and a material having low thermal conductivity is used as a material of the fixing portion of the supporting base. The film forming apparatus according to any one of claims 1 to 3, wherein the above object is achieved.

The invention of claim 5 of the present application is a film forming apparatus having a mechanism for flowing a purge gas from the back surface, wherein a purge gas exhaust port is provided in the vicinity of the purge gas exhaust port. This achieves the above-mentioned object.

The invention according to claim 6 of the present application is a metal thin film forming CVD apparatus.
The film forming apparatus as described in any one of 1 above, which achieves the above object.

The invention of claim 7 of the present application is the film forming apparatus according to claim 6 which is a blanket tungsten forming apparatus, and achieves the above object.

The invention according to claim 8 of the present application is the film forming apparatus according to claim 7, characterized in that the blanket tungsten CVD and the TiN CVD are continuously performed. To achieve.

The invention of claim 9 of the present application is the film forming apparatus according to claim 6 which is a selective tungsten forming apparatus, and achieves the above object.

[0024]

According to the first to fourth aspects of the present invention, by making the flow of the purge gas flow in the outer peripheral direction, for example, the laminar flow diffusing in the outer peripheral direction, the reaction gas is effectively supplied to the back surface of the semiconductor substrate. It is possible to suppress the wraparound. In particular, when the circumference of the contact portion (inner circumference susceptor), that is, the outer circumference of the semiconductor substrate is configured to have a low temperature,
This also suppresses film formation on the back surface of the semiconductor substrate.

In the above invention, the purge gas is caused to flow in the outer peripheral direction so as to smoothly flow, that is, to be a laminar flow, for example, so as to try to invade the back surface without affecting the reaction on the front surface of the substrate. Raw material gas can be removed. Therefore, it is possible to avoid unnecessary flow of the purge gas that may affect the original reaction, and to effectively suppress the raw material gas that enters the back surface. As a result, for blanket tungsten CVD, for example, it is possible to effectively suppress the W film from growing on the back surface of the semiconductor substrate having no adhesion layer.

Further, since the purge gas smoothly flows through the contact portion (inner peripheral susceptor), if the thickness of the susceptor plate at the peripheral portion is reduced, the amount of heat reaching the peripheral portion of the semiconductor substrate is smaller than that at other portions. Become. Therefore, the temperature of the circumferential portion of the semiconductor substrate is lowered. The present invention can also utilize this property. That is, the gas molecules trying to enter the back surface naturally enter from the outer periphery of the semiconductor substrate, but since the temperature of the outer periphery is low,
The reaction can be suppressed. Therefore, it is possible to minimize the deposition on the back surface of the semiconductor substrate.

According to the invention of claim 5 of the present application,
By introducing the purge gas from the rear surface of the wafer, the raw material gas flowing from the raw material gas introduction port on the front surface side of the wafer is diluted near the front surface of the wafer, whereby film formation on the rear surface of the wafer can be suppressed. At this time, if the purge gas flows out to the wafer front surface side, the raw material gas on the wafer surface to be formed is also diluted and the distribution is deteriorated.However, in the present invention, the flow of the purge gas is changed from the wafer back surface to the exhaust side. It can be configured to create a flowing laminar flow, so that the source gas flowing from the surface can be sufficiently diluted with a large amount of diluent gas. On the other hand, since the purge gas hardly flows into the surface of the wafer, the influence is small.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. Of course, the present invention is not limited to the illustrated embodiments.

Example 1 This example is an application of the invention of claims 1 to 4, and is embodied in an apparatus for blanket tungsten CVD in particular. Please refer to FIG.

The support base 2 of this embodiment has the following structure. That is, the contact portion 2a which is the first susceptor
Further, the fixed portion 2b which is the second susceptor allows the purge gas introduced from the rear (chuck) of the semiconductor substrate to pass between both susceptors. The first susceptor 2a is cut into a semicircular shape so that the purge gas smoothly flows. On the contrary, the second susceptor 2b is processed into a convex semi-circular shape. The susceptor is fixed by six screws (not shown). It is desirable that the fixed portion is as small as possible so that the flow of the purge gas is not disturbed, and the number of fixed portions is small.

By thus flowing the purge gas from the gas inlet II as shown by Ia and Ib in the figure, the flow cross section is made uniform and the flow is bent at a right angle so as not to create a turbulent flow. Therefore, a smooth curved flow can be formed, and as a result, the purge gas can flow in a laminar flow in the same direction as the main flow.

The following materials were used as the material of the susceptor of this embodiment.

Particularly in the case of blanket tungsten CVD, since temperature distribution is very important, quartz, alumina, and SUS, which have poor heat conduction, are used for the peripheral susceptor. As a result, it is possible to perform heating with good temperature uniformity and less heat escape from the contact portion 2a (first susceptor). In the case of this embodiment, graphite is used for the contact portion 2a (first susceptor) and SU is used for the fixed portion 2b (second susceptor).
S was used.

Next, the process conditions when blanket tungsten CVD is performed using the apparatus of this embodiment are shown.

(CVD condition of blanket tungsten) Nucleation step Source gas SiH ₄ / WF ₆ / H ₂ = 7/10/300
sccm Backside gas Ar 500 sccm Temperature 450 ° C., pressure 1 kPa (8 Torr) Bulk forming step Raw material gas WF ₆ / H ₂ = 25/500 sccm Backside gas Ar 1000 sccm Temperature 450 ° C., pressure 10 kPa (80 Torr)

As a result, a good-quality blanket tungsten CVD film was successfully obtained.

Embodiment 2 FIG. 2 shows the device structure of this embodiment. In this embodiment, the passage through which the purge gas flows is formed into a quarter circle shape and is realized by a short path. This is preferably used in a process performed at a relatively high pressure (10 kPa or more) where a laminar flow can be easily obtained without lengthening the purge gas path as shown in FIG. This feature is easy to install and easy to replace. 2, the same reference numerals as those in FIG. 1 indicate the same components as those in FIG.

Embodiment 3 FIG. 3 shows a device structure of this embodiment. In this embodiment, the surface (the surface on the lower side of the figure) is aligned with the surface of the semiconductor substrate 3 and made flat. For example, mating pins can be formed into a flat structure. In FIG. 3, the same symbols as those in FIG. 1 indicate the same components as those in FIG.

Example 4 In this example, an apparatus having the same configuration as in Example 1 was used,
This is an example of using this for selective tungsten CVD.

The shape of the support base 2 (susceptor) of this embodiment is the same as that for the blanket tungsten CVD of the first embodiment.

However, as for the material of the susceptor, in the apparatus of the first embodiment, the material of the fixing portion 2b (second susceptor) is quartz, sapphire glass, which is not selectively grown,
Use alumina, etc. In the case of this example, quartz was used.

Using this device, selective tungsten CV
The process conditions when performing D are shown.

(Selective Tungsten Formation Conditions) Source Gas SiH ₄ / WF ₆ / H ₂ = 7/10/100
0 sccm backside gas Ar 100 sccm temperature 450 ° C., pressure 60 Pa (0.5 Torr)

In the prior art, the by-products sometimes lost the selectivity. That is, the generated SiH _x F _y may be re-diffused on the semiconductor substrate 3 (wafer) and disturb the selectivity, but in the present example, there was no such problem.

Embodiment 5 This embodiment embodies the invention of claim 5.
The device according to the present embodiment has an RDR mechanism. RD
The R device is a high speed (300 to 100) wafer susceptor.
Rotation at 0 rpm) has the effect of uniformly diffusing the raw material gas on the wafer surface and the effect of making the raw material gas flow on the wafer surface a laminar flow in the horizontal direction by the rotation. As a result, the reaction by-product can be quickly exhausted to increase the reaction efficiency. An outline of this RD device is shown in FIGS. 12 and 13 as background art.

With only the structure shown in FIGS. 12 and 13, since the laminar flow is used, it is easily affected by the purge gas for preventing the film formation on the back surface of the wafer. Therefore,
In the embodiment, the invention of claim 5 is applied to reduce the flow rate of the purge gas flowing to the surface and reduce its influence. Furthermore, since the flow rate of the purge gas on the back surface is higher, the purge gas effect is large. In the case of this embodiment, it was possible to flow the purge gas in an amount 10 to 20 times that of the conventional apparatus.

That is, in this embodiment, the mechanism for spraying the purge gas around the wafer and the mechanism for exhausting the purge gas are provided close to each other, thereby increasing the flow rate of the purge gas and affecting the reaction gas. It was achieved to reduce the number.

In the apparatus of this embodiment, as shown in FIG. 4, a purge gas exhaust port IIb was installed in the film forming apparatus.

FIG. 5 is an enlarged view of the cross section of the purge gas discharge port to the back surface of the wafer and the purge gas discharge port (V part enlarged view of FIG. 4).

The introduction of purge gas in this embodiment is as follows.

Ar was used as the purge gas, and the inlet was used.
From IIa, through the lower part of the susceptor 2, arrows Ia, Ib
Introduce this like. The purge gas is once spread in the peripheral portion directly below the semiconductor substrate 3 (wafer) and then spreads to the outer peripheral portion. At this time, the purge gas Id is used for the wafer 3
In the horizontal part (see FIG. 5, which is an enlarged view), there is almost a laminar flow. Exhaust port is mostly around the wafer
It flows to IIb, and a part goes out to the wafer surface. This ratio can be dealt with by changing the conductance of Ar gas in the exhaust passage and the conductance of the introduction passage. In this embodiment, about 1/100 of the total flow rate is designed to flow to the surface. Note that IIc is the gap created by the combination,
The purge gas Ie slightly flows.

Using this apparatus, TiN was prepared under the following conditions.
A film and a W film were continuously formed. Rotation speed of susceptor is 5
It was set to 00 rpm.

(Conditions of TiNCVD) Temperature 450 ° C. to 650 ° C. Gas TiCl ₄ / NH ₃ / H ₂ = 5/20 / 80s
ccm pressure 30Pa backside Ar (purge gas) 1000sccm

(WCVD Formation Conditions) Temperature 450 ° C. Gas WF ₆ / H ₂ = 200/2000 sccm Pressure 10 kPa Backside Ar (purge gas) 5000 sccm

Here, the backside Ar has a large flow rate at the time of WCVD so as to suppress the formation of the W film in the portion where TiN is not formed. This is Ti
This is because the W film formed in a place without N easily peels off and causes particles.

According to this example, a good quality film could be formed satisfactorily.

[0057]

According to the present invention, the film formation on the back surface of the semiconductor substrate can be prevented, the generation of particles can be suppressed, and the purge gas from the back surface effectively acts, so that the flow rate of the purge gas can be reduced. Since the flow rate of the purge gas can be reduced, it is possible to provide a film forming apparatus that does not affect the film forming reaction on the semiconductor substrate and can improve the film thickness distribution.

Further, according to the present invention, it is possible to supply a large amount of purge gas, and it is possible to provide a film forming apparatus which can cope with a medium pressure process having a high gas concentration.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a first embodiment.

FIG. 2 is a configuration diagram showing a second embodiment.

FIG. 3 is a configuration diagram showing a third embodiment.

FIG. 4 is a configuration diagram showing a fifth embodiment.

FIG. 5 is a partial enlarged view showing a seventh embodiment.

FIG. 6 shows background art.

FIG. 7 shows background art.

FIG. 8 shows background art.

FIG. 9 shows background art.

FIG. 10 shows background art.

FIG. 11 shows background art.

FIG. 12 shows background art.

FIG. 13 shows background art.

[Explanation of symbols]

 1 Heating Device (IR Lamp) 2 Support (susceptor) 2a Contact part (first susceptor) 2b Fixed part (second susceptor) Ia to Ie Purge gas (flow) 3 Semiconductor substrate (wafer)

Claims (9)

[Claims] 1. A support base on which a semiconductor substrate is placed, a heating device for heating the semiconductor substrate via the support base, and a raw material for supplying a raw material gas for growing a thin film on the semiconductor substrate. A film forming apparatus having a gas supply means, wherein the purge gas is configured to flow in an outer peripheral direction of the support table. 2. A support base on which a semiconductor substrate is placed, a heating device for heating the semiconductor substrate via the support base, and a raw material for supplying a raw material gas for growing a thin film on the semiconductor substrate. In a film forming apparatus having a gas supply means, the support base is a contact portion that is at least a portion that comes into contact with a semiconductor substrate, and a fixing portion that is a portion that is fixed to the reaction chamber side wall on the outer periphery of the support base. And a gas direction control mechanism for diffusing the purge gas in the outer peripheral direction at a contact portion in contact with the semiconductor substrate. 3. A mechanism for introducing a purge gas between both parts of the divided support base is provided.
Alternatively, the film forming apparatus described in 2. 4. The material of the contact portion of the support base is made of a material having good thermal conductivity, and the material of the fixed portion of the support base is made of a material having low thermal conductivity. Item 5. The film forming apparatus according to any one of items 1 to 3. 5. A film forming apparatus having a mechanism for flowing a purge gas from the back surface, wherein a purge gas exhaust port is provided near the purge gas exhaust port. 6. The film forming apparatus according to claim 1, which is a metal thin film forming CVD apparatus. 7. The film forming apparatus according to claim 6, which is a blanket tungsten forming apparatus. 8. Blanket tungsten CVD and TiN
The film forming apparatus according to claim 7, wherein the CVD is performed continuously. 9. The selective tungsten forming apparatus according to claim 6.
The film forming apparatus according to.