JPH0347968A - Film forming device - Google Patents

Abstract

PURPOSE:To control the generation of particles and to form a film in a clean state by coating a holder for a substrate to be treated except the substrate setting part with a material nonselective to a gaseous reactant. CONSTITUTION:The peripheral part 3a of a holder 3 also used as an electrode except the part on which a substrate to be treated such as a semiconductor wafer 2 is set is coated with a material 3a nonselective to the gaseous reactant. As for the size of the part not to be coated, the interval (d) between the coating 3a and the wafer 2 is controlled to about 3-5mm in consideration of the precision in the alignment of position in setting the wafer 2 at the center of the holder 3, and the deposit caused by the gaseous reactant is not generated on this part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a film forming apparatus for forming a film on a substrate to be processed such as a semiconductor wafer.

[Prior Art] As devices become more densely packed and operate at higher speeds, multi-layer wiring structures and lower resistance are becoming more important, and techniques using metal or metal silicide for gate wiring have been developed. Metal CVD is a method for forming such a metal film.

That is, in metal CVD equipment, a semiconductor wafer protected by a susceptor for a processing chamber is heated to a high temperature, and WFG (tungsten hexafluoride) is introduced into the processing chamber as a reactive gas.
and 5IH4 (silane) and evacuated.

As a result, the substrate 21 of Si, Aρ, etc. is oxidized 822.
As shown in FIG. 4, a W (tungsten) film 40 is selectively formed on the surface of the semiconductor wafer 20 on which the oxide film 22 is formed. Ru.

By the way, in such metal CVD equipment, C
Prior to the VD process, self-cleaning is performed to remove the natural oxide film in the process chamber by etching. For this reason, metal CVD equipment uses an electrode material such as 5iC (silicon carbide) or metal as a susceptor, applies a high frequency voltage to this susceptor, first removes the natural oxide film with an etching gas, and then performs the above-mentioned CVD reaction. It is done.

[Problems to be Solved by the Invention] However, the electrode material (SiC1 metal, etc.) required for the susceptor for such etching is also non-selective to the reaction gas (WFc, etc.) for forming the metal film. Since it is not a material, tungsten or the like adheres to the peripheral portion of the susceptor 30 other than the portion where the wafer 20 is placed during the film forming reaction, as shown in FIG. Such a deposit 41 on the susceptor 30 is likely to peel off and cause particles to be generated. Particularly, in an apparatus that performs etching to remove a native oxide film as a pre-process of a film forming process, these particles become a major cause of wafer contamination during etching.

[Object of the Invention] The present invention solves the problems in the conventional film forming processing apparatuses described above, and provides a film forming processing apparatus that can minimize the generation of particles and perform film forming in an extremely clean state. The purpose is to

[Means for Solving the Problems] A film forming apparatus of the present invention that achieves the above object is an apparatus that forms a film by supplying a predetermined reaction gas to a substrate to be processed disposed in a processing chamber. The installation stand for the substrate to be processed is the installation part for the substrate to be processed or the processing chamber 1 around the installation stand 3.
A plurality of exhaust pipes 7 are connected to the upper wall, and these exhaust pipes 7 are collected into one exhaust pipe and connected to an exhaust port so that the conductance of the exhaust does not become high.

Further, in the lower part of the processing chamber 1, a reactive gas such as WF, (
Gas introduction mechanism 8.9 for supplying a mixed gas of tungsten hexafluoride) and Ar (argon) as a carrier gas, a mixed gas of 5iH4 (silane) and Ar, and N2 gas or N2 gas into the processing chamber 1. Further, a gas flow control plate 10 for controlling the gas flow of these reaction gases is provided facing the installation stand 3. The gas flow control plate 10 can be moved up and down by a drive mechanism 11, and by adjusting it to the optimal position, it can be applied to the processing surface of the semiconductor wafer 2.
The flow is controlled so that the reactant gases come into contact with each other more uniformly. Further, the installation table 3 is connected to a high frequency power source (not shown), and also serves as a flat plate electrode during etching. Note that the processing chamber 1, gas flow control plate 10, etc. are all at ground level.

The installation base 3, which also serves as an electrode, is coated with SiC (a material that is non-selective to the reaction gas except for carbon).

[Example] Hereinafter, an example in which the film-forming processing apparatus of the present invention is applied to a metal CVD apparatus will be described with reference to the drawings.

The processing chamber 1 of the CVD apparatus shown in FIG.
It is a cylindrical reaction chamber made of aluminum (aluminum), and the interior is kept airtight, and the wall surface can be cooled by a cooling mechanism (not shown).

Further, in the upper part of the processing chamber 1, an installation table 3 is provided on which a semiconductor wafer 2, which is a substrate to be processed, is placed so that the surface to be processed faces downward.

This installation stand 3 is provided with a support 5 for locking the outer peripheral edge of the semiconductor wafer 2 and fixing it to the installation stand 3, and the support 5 is driven by an elevating mechanism 4 such as an air cylinder. be done.

Further, above the installation stand 3, an IR lamp 6 is provided for heating the semiconductor wafer placed on the installation stand to a predetermined temperature, for example, 200 to 400°C.

4- Consists of materials constituting electrodes such as silicon oxide), metals, etc.
Further, as shown in FIGS. 2(a) and 2(b), the outer peripheral portion 3a excluding the portion where the semiconductor wafer 2 is placed is covered with a material 3a that is non-selective to the reaction gas.

Such a material is a material that does not cause deposits due to the reaction gas, and when the above-mentioned WF, SiH4 is used as the reaction gas, quartz (Sin2), for example, is suitable.

The coating 3a can be formed by masking the mounting table 3 with a mask material of the same shape and slightly larger than the semiconductor wafer 2, and then forming a film.

The size of the uncoated portion, that is, the size of the mask material, is determined by considering the alignment accuracy when installing the semiconductor wafer 2 at the center of the installation stand 3, and the gap d between the coating 3a and the wafer 2.
is set to be, for example, about 3 to 5 mm. If the gap d is too large, deposits due to the reaction gas will occur in this area, which is not preferable. Furthermore, if the gap d is too narrow, highly accurate positioning will be required when installing the semiconductor wafer 2, which is not practical.

In the configuration shown below, the metal CVD of this embodiment
The operation of the device will be explained.

First, self-cleaning is performed prior to the CVD process. That is, a voltage from a high-frequency power source with a predetermined frequency is applied to the installation table 3, and an etching gas such as NF3 (nitrogen trifluoride) is supplied from the gas introduction mechanism 8.9 to Ar (argon), He (helium), or N2. (Nitrogen), N2 (Hydrogen), or the like, and etching is performed at room temperature to 500° C. under a predetermined reduced pressure, for example, 0.05 to 0.3 Torr, thereby removing the natural oxide film in the processing chamber.

Next, the high frequency power source is turned off, the supply of etching gas is stopped, the etching gas in the processing chamber is exhausted, and the next CVD process begins.

Next, the semiconductor wafer 2 to be processed is taken out in a transport system (not shown), and orientation flat alignment and center alignment are performed using known optical means or the like. The semiconductor wafer 2 positioned in this manner can be installed on the installation table 3 by a transport means such as a robot 1 to an arm, and debossing can be prevented.

Therefore, even when the natural oxide film is etched in the previous etching process, the generation of particles due to etching of the debossing material can be prevented, and the adhesion of particles to the semiconductor wafer in the processing chamber 1 can be minimized. .

Although this embodiment describes a metal CVD device, the present invention is applicable not only to metal CVD devices but also to silicon nitride (
Needless to say, the present invention can be applied to various film forming processing apparatuses for forming SiN4) films, oxide films, etc.

[Effects of the Invention] As is clear from the above description, according to the film forming apparatus of the present invention, the non-installation portion of the installation table on which the object to be processed is installed is made of a material that is non-selective to the reaction gas. Since it is protected, it is possible to prevent the deposition of the film-forming substance on that part and the generation of particles due to it, and it is possible to perform processing with an extremely high degree of cleanliness.

Particularly, in the film forming apparatus of the present invention, the semiconductor wafer 2 is fixed to the installation table 3 by raising the support 5 by driving the lifting mechanism 4 for etching or the like.

Here, since the semiconductor wafer 2 has been aligned with its orientation flat and centered in advance, it is placed in the central portion of the installation table 3 where the coating 3a is not present.

After fixing the semiconductor wafer 2 in this way, the semiconductor wafer 2 on the installation stand 3 is heated in advance by an IR clamp, and the semiconductor wafer 2 is heated to a temperature suitable for CVD reaction, for example, 200 to 400℃.
Set to 00°C. Thereafter, the height of the gas flow control plate 10 is adjusted to a predetermined position, a predetermined reaction gas is introduced from the gas introduction mechanism 8.9, and a predetermined evacuation is performed from the exhaust pipe 8.

Thereby, for example, as shown in FIG. 3, the tungsten film 2c can be selectively formed in the interconnect hole between the oxides 2b formed on the silicon 2a of the semiconductor wafer 2.

In this case, the surface 3a of the installation stand 3 on which the semiconductor wafer 2 is not installed is coated with a non-selective material for reactive gases such as quartz, so it is optimal as a process device that integrates one type of process into this part 3a. be.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing one embodiment of the film forming processing apparatus of the present invention, FIGS. 2(a) and (b) are a plan view and a sectional view showing the main parts of the same apparatus, respectively, and FIG. 3 is a FIG. 4 is a sectional view showing the state of film formation on a substrate to be processed, and FIG. 4 is a diagram showing the state of film formation in a conventional film forming processing apparatus. 1...Processing chamber 2...Substrate to be processed 3...Installation table 3a...Coating

Claims (1)

[Claims] In an apparatus for forming a film by supplying a predetermined reaction gas to a substrate to be processed arranged in a processing chamber, the installation table for the substrate to be processed is non-selective to the reaction gas except for the part where the substrate to be processed is installed. A film forming processing apparatus characterized by being coated with a material.