JP3057094B2 - Substrate heating device - Google Patents

Description

The present invention relates to an apparatus for manufacturing a semiconductor device, and more particularly to a substrate heating apparatus.

(Prior Art) As one of methods for forming various thin films used in a manufacturing process of a semiconductor device on a substrate, a chemical vapor deposition (CVD) method is used.
Law).

This CVD method is a method in which a raw material gas is transported to a substrate surface and a thin film is formed by a chemical reaction on the substrate surface. Here, thermal energy, electric energy, or light energy is used to promptly advance the chemical reaction.

When a thin film is formed by such a CVD method, the substrate for improving the deposition rate and the film quality is often heated to a desired temperature.

As such an apparatus, a sample stage provided with a heater and a jig surrounding the sample stage have been considered. For example, when a tungsten film is formed by heating a substrate and using tungsten hexafluoride and silane as source gases, a jig is made of quartz, and a heat reflection film such as an aluminum film is deposited on the inner wall of the jig. Has the effect of preventing heating of the jig and suppressing film growth on the jig.

However, there is a gap between these mating surfaces due to problems in processing accuracy of the substrate, sample table, jig, warpage due to heating, etc., and a tungsten film grows inside, and the temperature distribution becomes nonuniform, There have been problems that affect the deposition rate, uniformity and selectivity, and cause generation of dust.

(Problems to be Solved by the Invention) As described above, in the conventional substrate heating apparatus, a tungsten film grows inside the substrate, the sample table, and the jig because a gap is formed between the mating surfaces, and thus the temperature distribution is increased. However, there are problems that the film becomes non-uniform, the deposition rate on the substrate surface is affected, the uniformity and selectivity of the film are deteriorated, and dust is generated.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a substrate heating apparatus which solves the above-described problem caused by a gap between a mating surface of a substrate, a sample table, and a jig.

[Configuration of the invention]

(Means for Solving the Problems) In order to solve the above-described problems, a substrate heating apparatus according to claim 1 includes a container into which a raw material gas is introduced, a reaction chamber formed inside the container, and a reaction chamber formed inside the container. A sample table on which a substrate is installed, a jig provided around the periphery of the sample table, a substrate heating means for heating the substrate, and a relative movement of the jig and the substrate. A clamping means for clamping an outer peripheral portion of the substrate between the sample table and the jig; and a telescopic member for exerting a force in a direction in which the jig and the substrate are brought closer to each other. The tool and the substrate are tightly adhered to each other so that the structure formed by the sample stage and the jig is sealed from the surroundings.

Further, the substrate heating apparatus according to claim 2 includes a container into which the raw material gas is introduced, a reaction chamber formed inside the container, a sample table installed in the reaction chamber, on which the substrate is mounted, and A jig provided to surround the periphery of the upper portion of the table, substrate heating means for heating the substrate, and a relative movement of the jig and the substrate so that an outer peripheral portion of the substrate is fixed to the sample table and the jig. And a stretchable rubber formed between the jig and the bottom of the reaction chamber, and the jig and the stretchable rubber are provided by the sandwiching means and the stretchable rubber. The structure is characterized in that the structure formed by the sample stage and the jig is sealed from the surroundings by the close contact of the substrate with no gap.

(Operation) In the substrate heating apparatus according to the present invention, since the elastic member seals the inside of the structure including the sample table on which the substrate is mounted and the jig surrounding the sample table from the surroundings,
It is possible to eliminate an error in the processing accuracy of the sample table, the jig, and the like and a gap between these mating surfaces caused by warpage during heating. Therefore, the raw material gas is prevented from flowing to the surfaces of the sample table and the jig through the gap, and no thin film is formed on these surfaces. As a result, it is possible to improve the speed of forming a thin film on the substrate surface, prevent dust, improve the selectivity of the uniformity of film formation, and stabilize the control of the substrate temperature.

(Example) Next, an example according to the present invention will be described in detail with reference to the drawings.

First Embodiment FIGS. 1A and 1B are cross-sectional views showing the configuration of a first embodiment of a substrate heating apparatus according to the present invention. FIG. 1A is a cross-sectional view of the device when the substrate is fixed, and FIG. 1B is a cross-sectional view of the device when the substrate is released. The apparatus of this embodiment is a single-wafer, low-pressure CVD apparatus incorporating a resistance heating element.

In FIG. 1A, a container 1 is made of an aluminum alloy, and the wall of the container 1 is water-cooled by a cooling pipe 2. The inside of the container 1 is a reaction chamber 3 for forming a thin film by a low pressure CVD method. A source gas can be supplied to the reaction chamber 3 by a source gas supply pipe 4. An exhaust port 5 connected to an exhaust system (not shown) is formed at the bottom of the reaction chamber 3 so that the pressure inside the reaction chamber 3 can be reduced.

A quartz susceptor 6 is arranged at the bottom of the reaction chamber 3, and a heater 8 for heating the substrate 7 is fixed on the quartz susceptor 6 via a spring 9. The quartz susceptor 6 and the heater 8 constitute a sample stage.

On the other hand, the side walls of the heater 8 and the quartz susceptor 6 are covered with a quartz fixing jig 10 when fixing the substrate. An aluminum film 11 is formed on the surface of the quartz fixing jig 10 on the heater 8 side as heat reflecting means for reflecting heat from the heater 8.

Here, the substrate 7 is fixed and released as follows. As described above, the substrate 7 is placed on the heater 8, and a force is applied to the heater 8 to push it upward from the spring 9. On the other hand, an elevating mechanism 12 for vertically fixing and releasing the substrate 7 on the heater 8 is provided below the fixing jig 10. When the substrate 7 is fixed on the heater 8 and heated, as shown in FIG.
Is moved downward by the elevating mechanism 12, and the fixing jig 10 is moved.
Is brought into close contact with the upper surface of the quartz susceptor 6. At this time, the outer peripheral portion of the substrate 7 is sandwiched between the upper surface of the heater 8 and the upper end of the surface of the fixing jig 10 on the heater 8 side by the force pushing upward from the spring 9. Is fixed. Conversely, when the substrate 7 is released on the heater 8 and transported, the fixing jig 10 is moved upward by the elevating mechanism 12 as shown in FIG.

Finally, the heater 8 will be described. The heater 8 has a structure in which the periphery of a tungsten wire 13 is covered with alumina 14. The tungsten wire 13 becomes a heating element by applying a voltage and causing a current to flow, thereby heating the substrate 7. The tungsten wire 13 is connected to a stretchable nickel wire 15 spirally wound with a silver braze, and the nickel wire 15 is connected to a copper wire 16. In addition, this copper wire 16
Is connected to a power supply (not shown), and controls the voltage so as to keep the temperature of the substrate 7 constant.

Generally, there is a limit to the precision processing of the fixing jig 10,
Even if the processing can be performed so that the bottom surface of the fixing jig 10 and the upper surface of the quartz susceptor 6 are in close contact, it is difficult to perform processing so that there is no gap between the substrate 7 and the fixing jig 10. Further, even if the processing can be completely performed, warpage occurs in each part of the apparatus at the time of heating, and a gap is easily formed. According to this embodiment, since the outer periphery of the surface of the substrate 7 is pressed against the upper end of the surface of the fixing jig 10 on the heater 8 side by the spring 9, no gap is formed. Therefore, the raw material gas passes through the gap and passes through the heater 8 on the surface of the heater 8 and the fixing jig 10.
Of the quartz susceptor 6 is prevented, and no thin film is formed on these surfaces. Therefore, the speed of forming a thin film on the surface of the substrate 7 can be improved, the generation of dust can be prevented, the uniformity and selectivity of film formation can be improved, and the control of the substrate temperature can be stabilized.

Next, the effect of repeatedly depositing a tungsten film selectively on silicon of a silicon substrate covered with a silicon oxide film pattern using the apparatus shown in FIG. 1 will be described.

Using the heater 8 of the apparatus of FIG.
After heating to 10 ° C., 10 sccm of tungsten hexafluoride and 10 sccm of silane were introduced into the reaction chamber 3 as a raw material gas, and the pressure of the reaction chamber 3 was set to 0.005 Torr. Next, a tungsten film was repeatedly deposited selectively on the silicon portion of the silicon substrate 7 which was not covered with the silicon oxide film.

In the case of the conventional apparatus, the tungsten film does not deposit on the surface of the fixing jig due to the effect of the aluminum film, but the reactive film passes through the gap between the substrate and the fixing jig and the gap between the fixing jig and the quartz susceptor. The source gas flowed around, and a tungsten film gradually grew on the surface of the heater, the surface of the fixture on the heater side, and the surface of the quartz susceptor. On the other hand, in the apparatus of this embodiment, the gap caused by the error of the processing accuracy and the warpage at the time of heating is absorbed by the elastic spring 9, so that the above-mentioned raw material gas does not wrap around and the film is repeatedly formed. The heater 8 on the surface of the heater 8 and the fixing jig 10
The tungsten film did not grow on the side surface and the upper surface of the quartz susceptor 6. Further, it was confirmed that the above-described effects were obtained.

Second Embodiment Next, a second embodiment of the present invention will be described.

2 (a) and 2 (b) are cross-sectional views showing the configuration. FIG. 2A is a cross-sectional view of the device when the substrate is fixed, and FIG. 2B is a cross-sectional view of the device when the substrate is released.
In this figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description is omitted. The apparatus of this embodiment is also a single wafer type reduced pressure CVD apparatus incorporating a heating element.

This embodiment differs from the apparatus shown in FIG.
An elastic bellows 23 is attached from the back side of the jig 21 to a ring-shaped fixing jig 21 having a heat-reflective aluminum film 22 formed on the back side. Is that a ring-shaped projection 1a is provided, and a quartz susceptor 6 and a heater 8 are installed inside the ring. Here, the bellows 23 are tightly fixed to the back surface of the fixing jig 21 and the upper surface of the protrusion 1a, and when the bellows 23 shrinks, the fixing jig 21 receives a downward force. 24 is a copper wire provided for applying a voltage to the tungsten wire 13.

Next, the operation of the device when fixing and releasing the substrate 7 will be described. When the substrate 7 is fixed on the heater 8 and heated, the fixing jig 21 is moved downward by the lifting mechanism 12 as shown in FIG. At this time, since the jig 21 receives a downward force also by the bellows 23,
The outer peripheral portion of the substrate 7 is sandwiched between the back surface of the jig 21 and the upper surface of the heater 8, thereby fixing the substrate 7. vice versa,
When the substrate 7 is released on the heater 8 and transported, the fixing jig 21 is moved upward by the lifting mechanism 12 as shown in FIG.

According to this embodiment, the gap generated between the fixing jig 21 and the substrate 7 or between the bellows 23 and the fixing jig 21 and the protrusion 1a due to the processing accuracy error and the warpage at the time of heating, Can be absorbed by bellows 23 having Therefore, it is possible to prevent the reactive raw material gas from flowing around the surface of the heater 8 and the like, and the same effect as in the first embodiment can be obtained.

Third Embodiment Next, a third embodiment of the present invention will be described.

3 (a) and 3 (b) are cross-sectional views showing the configuration. FIG. 3A shows the state when the substrate is fixed.
Is a cross-sectional view of the device when the substrate is released. In this figure, the same parts as those in FIG. 2 are denoted by the same reference numerals, and detailed description will be omitted. This apparatus is also a single wafer type reduced pressure CVD apparatus incorporating a resistance heating element.

The difference between this embodiment and the apparatus shown in FIG.
A projection 31a is provided at the lower portion of the outer periphery of a ring-shaped fixing jig 31 having a heat-reflective aluminum film 32 formed on the back surface, and a rubber such as Viton is used instead of the bellows 23 described in the second embodiment. The point is that an O-ring 33 made of aluminum is used. Here, this O-ring 33 has a container 1
Embedded in the outer periphery of the projection 1a.

Next, the operation of the device when fixing and releasing the substrate 7 will be described. When the substrate 7 is fixed on the heater 8 and heated, the fixing jig 31 is moved downward by the elevating mechanism 12 as shown in FIG. At this time, the O-ring
The upper part of the substrate 33 shrinks, and the outer periphery of the substrate 7 is fixed to the fixing jig 31.
Of the heater 8 and the upper surface of the heater 8, whereby the substrate 7 is fixed. At this time, the O-ring 33 also comes into close contact with the inner surface of the projection 31a. Conversely, when the substrate 7 is released on the heater 8 and transported, the fixing jig 31 is moved upward by the lifting mechanism 12 as shown in FIG. 3 (b).

According to this embodiment, the gap generated between the fixing jig 31 and the substrate 7 due to an error in processing accuracy or warpage during processing and the gap between the back surface of the fixing jig 31 and the O-ring 33 are expanded and contracted. Can be absorbed by the O-ring 33 which has the property. Therefore, the same effects as in the first embodiment can be obtained.

 The present invention is not limited to the above embodiment.

For example, any heating method using a heating element may be used, and any cooling method for a container may be used. Further, the method of selectively depositing tungsten on the surface of the silicon substrate described in the above embodiment is merely an example, and the present invention can be applied to all applications in which a thin film is formed while being heated by a CVD method or the like. In addition, the present invention can be variously modified and implemented without departing from the gist.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to the substrate heating apparatus by this invention, the thin-film formation rate on a substrate surface is improved, generation | occurrence | production of dust is improved, uniformity and selectivity of a film formation are improved, Furthermore, control of a substrate temperature is stabilized. .

[Brief description of the drawings]

FIGS. 1, 2, and 3 are cross-sectional views showing the configurations of first, second, and third embodiments of the substrate heating apparatus according to the present invention, respectively. In the figures, 1 ... container, 1a ... protrusion, 2 ... cooling pipe, 3 ... reaction chamber, 4 ... material gas supply pipe, 5 ... exhaust port, 6 ... quartz susceptor, 7 ... substrate , 8 ... heater, 9 ... spring, 10,21,31 ... quartz fixing jig, 11,22,32 ... aluminum film, 12 ... elevating mechanism, 13 ... tungsten wire, 14 ... Alumina, 15: Nickel wire, 16, 24: Copper wire, 23: Bellows, 33: O-ring, 31a: Protrusion.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shigehiko Kaji 72 Horikawacho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture Inside the Toshiba Horikawacho Plant (72) Inventor Haruo Okano 72 Horikawacho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture Co., Ltd. Inside the Toshiba Horikawa-cho Plant (72) Inventor Toru Watanabe 72 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba Horikawa-cho Plant (56) References 167036 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 16/00-16/56 H01L 21/203-21/205 H01L 21/285 H01L 21/31

Claims (3)

(57) [Claims] 1. A container into which a raw material gas is introduced, a reaction chamber formed inside the container, a sample table installed in the reaction chamber, on which a substrate is mounted, and a peripheral edge of an upper portion of the sample table. A surrounding jig, a substrate heating means for heating the substrate, and a relative movement of the jig and the substrate, thereby sandwiching an outer peripheral portion of the substrate between the sample table and the jig. Sandwiching means, comprising an expandable member that exerts a force in a direction to bring the jig and the substrate closer, by the close contact of the jig and the substrate with no gap by the expandable member,
A substrate heating apparatus for sealing a structure formed by the sample table and the jig from the surroundings. 2. A container into which a raw material gas is introduced, a reaction chamber formed inside the container, a sample table installed in the reaction chamber, on which a substrate is mounted, and a peripheral portion of an upper portion of the sample table. A surrounding jig, a substrate heating means for heating the substrate, and a relative movement of the jig and the substrate, thereby sandwiching an outer peripheral portion of the substrate between the sample table and the jig. A gripping means, and an elastic rubber formed between the jig and the bottom of the reaction chamber, wherein the jig and the substrate are tightly adhered to each other by the gripping means and the elastic rubber. A substrate heating apparatus, thereby sealing a structure formed by the sample stage and the jig from the periphery. 3. The substrate heating apparatus according to claim 2, wherein an aluminum film is formed on a back surface of said jig corresponding to an outer peripheral portion of the substrate sandwiched by said sandwiching means.