JPS63179077A - Thin film forming device - Google Patents

Abstract

PURPOSE:To inhibit the formation of a thin film on a part other than a substrate and to prevent the sticking of dust to the substrate by placing a heating source for directly heating the substrate in a CVD device so that the interior parts of the device are hardly heated except the substrate. CONSTITUTION:This thin film forming device is provided with a substrate support 17 for supporting a substrate 18 to be treated set in a vessel 11 and a heating source 20 placed in noncontact with the support 17 and in contact with the rear side of the substrate 18. Prescribed gases are fed to the surface of the substrate 18 from gas introducing pipes 15a, 15b and a thin film is deposited by CVD.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a thin film forming apparatus by chemical vapor deposition (CVD), and in particular, the present invention relates to a thin film forming apparatus using a chemical vapor deposition method (CVD method). The present invention relates to an III film forming apparatus that forms an i1 film.

(Prior art) The CVD method is one of the thin film forming methods in the manufacturing process of integrated circuits.For example, it is used to form polycrystalline silicon using silane (SiH<) gas as a raw material, or to form polycrystalline silicon using organic silane as a raw material. It has been put into practical use for forming silicon oxide films, etc. Also,
Recently, the formation of aluminum thin films using organic aluminum as a raw material and the formation of high melting point metals and their silicide films using high melting point metal halides as raw material gas have also been studied.

There are two types of CVD methods: normal pressure CVD, in which the I film is formed under atmospheric pressure, and low pressure CVD, in which the I film is formed under reduced pressure. The low-pressure CVD method, which has the above-mentioned features, has become mainstream. Also,
When forming a single film on a large-area substrate or a substrate with a fine surface shape, instead of forming a thin film on multiple substrates at once (batch method), place one substrate in the reaction chamber. A method (single wafer method) in which thin films are formed by arranging the wafers one by one is being considered.

However, the following problem occurs in the single-wafer thin film formation aW1 using the low pressure CVD method.

In other words, in this device, the substrate is normally placed on a substrate support that includes a heat source such as a sheathed resistor, and thin films are formed while heating the substrate, but the heating efficiency of the substrate decreases significantly under reduced pressure. . This is because even if the surfaces of the substrate and the substrate support are mirror-finished, there is a microscopic gap between them, and heat conduction is mainly due to radiation under reduced pressure. This causes problems that the substrate cannot be heated to the temperature required for CVD or that the surface temperature of the substrate support is higher than the substrate surface temperature. In particular, the latter brings about the following disadvantages.

That is, since the substrate support member or the vicinity of the substrate of the reaction vessel is in a high temperature state, the thin film that should be formed on the substrate is also formed on the surface of the substrate support member and the like.

The ii* formed on the surface of the substrate support member grows each time the thin film formation is repeated, and eventually peels off from the substrate support member and adheres to the substrate as dust. A substrate with a large amount of dust attached becomes defective, resulting in a decrease in the yield of integrated circuits.

In addition, the reaction gas in the reaction chamber reacts and is consumed not only on the substrate but also on the surrounding substrate support member or the inner wall of the reaction vessel that is at a high temperature, which reduces the deposition rate of the thin film on the substrate. . Additionally, thin films formed on substrate support members result in an increase in by-product gases resulting from thin film formation.

This increase in by-product gas complicates the gas composition near the substrate surface, making it difficult to control the CVD process and the film quality of the thin film.

(Problems to be Solved by the Invention) As described above, in conventional thin film forming apparatuses using the low pressure CVD method, it is not possible to sufficiently heat the substrate, and the substrate support member or reaction vessel around the substrate is A thin film is also formed on the surface of the inner wall, which reduces the yield of integrated circuits.

There were problems such as a decrease in the rate of thin film formation on the substrate and an increase in by-product gas.

The present invention has been made in consideration of the above circumstances, and its purpose is to be able to suppress the formation of a1Ml on members other than the substrate, such as a substrate support member, and to improve the yield of integrated circuits and increase the thin film deposition rate. It is an object of the present invention to provide a thin film forming apparatus that can improve the quality of the film.

[Structure of the Invention] (Means for Solving the Problems) The gist of the present invention is to heat only the substrate on which the sm is to be formed,
The objective is to suppress the temperature rise of parts other than the substrate, such as the substrate support member, as much as possible.

That is, the present invention provides a thin film forming apparatus that supplies a predetermined gas to the surface of a substrate placed in a container and deposits a thin film on the surface of the substrate by chemical vapor deposition, in which the substrate is supported. The substrate support is provided with a heating source that directly heats the substrate in a state where the substrate support is in non-contact and substantially in contact with the back surface of the substrate.

(Function) According to the present invention, since the heating source is brought into direct contact with the back surface of the substrate to be processed, it is possible to increase the heating efficiency of the substrate, and it is also possible to make the temperature of the substrate support lower than the surface temperature of the substrate. becomes. Therefore, the formation of a thin film on the substrate support member or the inner surface of the reaction vessel is suppressed, and the adhesion of dust to the substrate surface is suppressed.

(Example) Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

The figure is a sectional view showing a schematic configuration of a thin film forming apparatus according to an embodiment of the present invention. In the figure, 11 is a container made of a metal plate such as stainless steel, and the inside thereof forms a reaction chamber 12 for forming 1JIII by a low pressure CVD method.

The reaction chamber 12 is connected to the container 1 via valves 13a and 13b.
1. Reaction gas supplying vibes 14a and 14b are drawn in from the side of the annular gas introduction vibe 15, and a large number of gas discharge holes are formed upward at the tips of the vibes 14a and 14b.
a and 15b are connected. At the bottom of the reaction chamber 12,
An exhaust port 16 connected to an exhaust system (not shown) is formed.

At the top of the reaction chamber 12, a substrate support 17 is provided, which is formed by hollowing out the bottom of a cylindrical body with a bottom to a diameter slightly smaller than the substrate diameter. This substrate support 17 has a flat substrate mounting surface 17.
A substrate 18, such as a silicon wafer, to be used for forming a thin film is placed on this surface 17a. At this time, the substrate 18 is positioned by positioning bins 19 erected at, for example, three locations on the periphery of the substrate mounting surface 17a.

A heating source 2o is provided in contact with the upper surface (back surface) of the substrate 18. This heat source 20 is constructed by forming a recess on the lower surface of a heater support 21 made of quartz, and embedding a heater 22 in this recess. The heater 22 is made of, for example, a tungsten wire, and a portion thereof protrudes slightly below the lower surface of the heater support 21. The protruding heater 22 comes into contact with the back surface of the substrate 18.

The substrate support 17 is supported by a shaft 32 connected to a pneumatic bellows valve 31 that penetrates the earthen wall of the container 11, and moves up and down as the shaft 32 expands and contracts. Further, a side wall of the container 11 is provided with a board insertion/removal opening that can be opened and closed by a lid 33. Then, the substrate support 17 descends due to the extension of the shaft 32,
In this state, the board 18 is replaced through a board insertion/removal port provided on the side wall of the container 11.

In FIG. 1, 34 is a cylindrical heat shield placed between the heat source 20 and the substrate support 17, and 35 is the heater 2.
2 lead wires are shown. Also, 36 is heating 3!20
Ar gas is flowed over the surface of the substrate, and the pressure on the back side of the substrate is set to 0.01 to 10 torr than the pressure on the reaction chamber 12 side while heating the substrate.
A gas supply vibe to raise the temperature, 37 is this vibe 3
The valve connected to 6 is shown.

Next, a procedure for forming a tungsten thin film on the substrate 18 using this apparatus will be described.

First, prior to thin film formation, the reaction chamber 1 is
Evacuate the inside of 2. Next, for example, 500 cc/m of Ar is supplied from the gas introducing vibrator 15a through the vibrator 14a.
i.n. to bring the inside of the reaction chamber 12 into a pressure state of, for example, 1 Qtorr. In parallel with this, 50 cc/1n of Ar is flowed from the gas supply via 36 to bring the internal space of the substrate support 17 into a pressure state of, for example, 11 tOrr. In this state, the heater 22 of the heat source 20 is energized to heat the substrate 18. In this case, the internal space of the substrate support 17 is
By setting the pressure slightly higher than that in board 1,
8 is effectively heated. Further, since the heater 22 is in direct contact with the back surface of the substrate 18, the heating efficiency is high and the substrate 18 is quickly heated to a predetermined temperature, for example, 200 to 1000°C.

Next, the valve 13a is closed to stop the supply of Ar from the gas introduction pipe 15a, and then the valves 13a and 13b are opened to close the gas supply vibrator 14a.

14b to WFs gas 0.1 to 5 tor, respectively.
r.

Introduce H2 gas from 0.5 to 10 torr. These two types of introduced gases are discharged into the reaction chamber 12 from the gas introduction vibes 15a and 15b. In this state, the inside of the reaction chamber 12 is maintained in a reduced pressure state, and tungsten 1119 is formed on the surface of the substrate 18 by CvD. At this time, since the inside of the reaction W12 is in a reduced pressure state, the heat source 20
Since the heat conduction from the substrate 18 to the substrate support 17 is significantly reduced, the surface temperature of the substrate support 17 becomes sufficiently lower than the surface temperature of the substrate 18 (approximately 500°C), and in this state, the tungsten+1 film is applied to the substrate 18. is deposited.

Thus, according to the present apparatus, not only can tungsten 7all be deposited on the surface of the substrate 18 in the same way as in the conventional method, but also
The following effects can be obtained. That is, since the temperature of the substrate support 17 is sufficiently lower than the temperature of the substrate 18, the deposition rate of the thin film deposited on the substrate support 17 is extremely low. Furthermore, the rate of deposition of the thin film on the inner wall of the container 11 is similarly reduced. In other words, adhesion of the tungsten thin film to parts other than the substrate 18 can be suppressed. Therefore, it is possible to prevent inconveniences such as the thin film attached to the substrate support 17 and the like other than the substrate 18 peeling off and adhering as dust on the substrate 18, contributing to an improvement in the yield of integrated circuits, etc. . Furthermore, i'1ll to other than the board 18
Since there is little adhesion of II! to the substrate 18, the utilization efficiency of the gas introduced into the reaction chamber 12 can be increased.
The deposition rate of l is increased. In addition, since less thin film is deposited on the substrate support 17 etc., the amount of by-product gas generated is reduced, and for example, selectivity can be improved when performing selective thin film formation. .

Note that the present invention is not limited to the embodiments described above. For example, the thin film to be formed is not limited to tungsten, but can also be applied to III film formation of SiO2, polycrystalline silicon, and the like. In the case of S i 02, for example, the substrate temperature is set to 500
~800°C, TE01 (tetraethyl orthosilicate) gas at 1~200 torr/1n, N2
Deposition may be performed by supplying gas at 100 to 1000 torr/1n. Furthermore, in the case of polycrystalline silicon, the substrate temperature is set at 800 to 1000°C, and the SiH4 gas is heated at 0.5°C.
1-1 torr/1n, H2 gas 1-10tO
Deposition may be performed by supplying rr/ff1in.

Further, the heater and heater support constituting the heat source are not limited to tungsten, quartz, etc., and may be made of any material that does not become a source of contamination to the substrate to be processed. Furthermore, in the example, the weight was 111g with the substrate surface facing down! Although the description has been given using an example in which deposition is performed, it is also applicable to a method in which WJ film is deposited with the substrate surface facing upward. Furthermore, the heating source and the back surface of the substrate do not necessarily need to be in complete contact with each other, but only need to be in substantial contact with each other. In addition, various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As detailed above, according to the present invention, the substrate to be processed is directly heated and heating of parts other than the substrate is suppressed as much as possible. formation can be reduced. Therefore, it is possible to prevent dust from adhering to the substrate, thereby contributing to improving the manufacturing yield of integrated circuits, and further improving the thin film formation speed.

[Brief explanation of the drawing]

The figure is a sectional view showing a schematic configuration of a thin film forming apparatus using a CVD method according to an embodiment of the present invention. 11... Container, 12... Reaction chamber, 13a, -. 13c, 37... valve, 14a, ~, 14c. 36... Gas supply pipe, 15a, ~, 15C...
Gas introduction pipe, 16... Exhaust port, 17... Substrate support, 18... Substrate to be processed, 20... Heat source, 2
1... Heater support, 22... Heater.

Claims (4)

[Claims] (1) In a thin film forming apparatus that supplies a predetermined gas to the surface of a substrate to be processed placed in a container and deposits a thin film on the surface of the substrate by chemical vapor deposition, a substrate that supports the substrate to be processed. A thin film forming apparatus comprising: a support; and a heat source that is provided in a non-contact manner with the substrate support and in contact with the back surface of the substrate, and directly heats the substrate. (2) A patent characterized in that the heat source is formed by providing a recess in the surface of a quartz plate serving as a heater fixture, and embedding a heater in contact with the back surface of the substrate to be processed in the recess. A thin film forming apparatus according to claim 1. (3) The thin film forming apparatus according to claim 2, wherein the heater is a tungsten wire. (4) The thin film forming apparatus according to claim 1, wherein the substrate support supports the substrate to be processed with its surface facing down.