JPH07118464B2 - Plasma deposition device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a plasma deposition device, and particularly to an interlayer insulating film or protective film (SiN _x film or SiO ₂ film) in a semiconductor integrated circuit or the like.
ECR (Electron Cyclotron Resonanc
e: Electron cyclotron resonance) plasma CVD apparatus.

[Conventional technology]

As a method for forming an insulating film or the like of the semiconductor integrated circuit as described above, a plasma CVD method has been conventionally used.
In this plasma CVD method, for example, a substrate is placed on a mounting table in a reaction chamber, parallel plate electrodes are provided facing the substrate, and high frequency is applied to the electrodes to cause glow discharge, thereby The film is formed by exciting the reaction gas to cause a reaction while keeping the substrate at a low temperature.

By the way, recently, an ECR plasma CVD method has been developed as a kind of plasma CVD method and has already been put to practical use. This ECR
The plasma CVD method is a method of forming a film by combining an ECR ion source and a divergent magnetic field, which is a characteristic that cannot be obtained by a normal plasma CVD method, that is, a film can be formed at a lower temperature.
It has various characteristics such as high film forming speed.

The ECR plasma CVD method will be briefly described below. The configuration of the apparatus mainly includes a plasma chamber for generating plasma, an electromagnetic coil as a magnetic circuit arranged around the plasma chamber, and a substrate. It consists of a reaction chamber. Then, a gas for generating plasma and microwaves are introduced into the plasma chamber, and a magnetic field satisfying an electron cyclotron resonance condition for the introduced microwaves is formed in the plasma chamber by a low gas pressure. To form a high density plasma. Further, the magnetic field is a divergent magnetic field, and the plasma generated in the plasma chamber is guided to the reaction chamber along the divergent magnetic field, where it reacts with the reaction gas to form a thin film such as an insulating film on the substrate. .

[Problems to be Solved by the Invention]

As described above, such an ECR plasma CVD method has an advantage that a film can be formed at a low temperature and a film forming speed is high. However, in terms of the area of the substrate on which a film can be formed and the uniformity thereof, the conventional normal plasma CVD apparatus can form a film on a substrate of 800 × 800 to 1000 × 1000 mm, and is uniform. Sex is ± 5 within the above range
While the value is%, in the ECR plasma CVD device,
It is about 4 to 8 inches (100 to 200 mm), and the film thickness uniformity is about ± 5% in the 6 inch range, which is problematic in that the substrate has a large area and the film thickness is uniform.

Therefore, it is conceivable to increase the size of the conventional ECR plasma CVD apparatus itself as it is, but if this is done, the problem is whether the mode configured in the plasma chamber will become a predetermined mode and uniform plasma will be generated. In addition, in order to generate a magnetic field that satisfies the electron cyclotron resonance condition in the plasma chamber, the electromagnetic coil naturally becomes large in size, and there is a problem of uniformity of magnetic flux distribution and weight. It seems difficult to achieve area and uniformity. Furthermore, due to the larger size of the device,
There is also a problem that radicals, that is, isotropic molecules also increase, and such molecules adhere to the substrate so that a good-quality film cannot be formed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a plasma deposition apparatus capable of reliably and easily performing uniform film deposition on a large-area substrate.

[Means for Solving the Problems]

The plasma deposition apparatus according to the present invention is, in the ECR plasma CVD apparatus, provided with a plurality of plasma chambers, and provided with a deposition preventive cover having an opening in the central portion in the vicinity of the substrate between the plurality of plasma chambers and the substrate. The film is formed through the opening of the deposition preventive cover while moving the substrate.

[Action]

In the present invention, by the operation of the usual ECR plasma CVD method, plasma is generated in a plurality of plasma chambers, these are drawn out by a divergent magnetic field and introduced into the reaction chamber, and the reactants are placed on the substrate along each plasma flow. To reach. Therefore, the plasma flow is irradiated over a large area, and a film can be formed on a large area substrate. Moreover, since the substrate is moved and the deposition cover having an opening is installed in the vicinity of the substrate, only the uniform plasma flow is applied to the entire surface of the moving substrate through the opening of the deposition cover. Therefore, a uniform film is formed over a large area.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional configuration diagram of a plasma deposition apparatus according to an embodiment of the present invention. In the figure, 11 and 12 are plasma chambers configured to be cavity resonators, respectively, although not shown. A microwave introduction window, a microwave extraction window, etc. are provided. In addition, a gas inlet for introducing a gas for plasma generation into each of the plasma chambers 11 and 12.
11a and 12a are provided, and rectangular waveguides 21 and 22 for introducing microwaves are connected. The rectangular waveguides 21 and 22 are connected to a microwave source (not shown) via a T branch 20. As the microwave source, a magnetron with a frequency of 2.45 GHz is used here.

Electromagnetic coils 3 and 3a as magnetic circuits are arranged around the plasma chambers 11 and 12, respectively.
And 3a, the strength of the magnetic field is determined such that the conditions of electron cyclotron resonance by microwaves are satisfied inside the plasma chambers 11 and 12. Where the frequency 2.45
The magnetic flux density for causing electron cyclotron resonance for GHz microwaves is 875 Gauss. The magnetic field generated by the electromagnetic coils 3 and 3a becomes a divergent magnetic field that diverges upward.

A reaction chamber 4 is provided above the plasma chambers 11 and 12, and the plasma chamber 1 is provided in the reaction chamber 4.
Substrate 5 is arranged so as to face 1 and 12. The substrate 5 is held by a substrate holder (not shown) and can reciprocate in the left-right direction in the drawing. An adhesion-preventing cover 6 is provided below the substrate 5 close to the substrate 5, and an opening 6a is formed in the center of the adhesion-preventing cover 6. That is, this opening
As shown in the plan view of FIG. 2, 6a is formed corresponding to a region where the substrate 5 is irradiated with the uniform plasma flow P. Further, in the reaction chamber 4, the plasma chambers
Shutters 71, 72 facing the plasma outlets of 11, 12
Is openable and closable. In addition, 8 is this reaction chamber 4
A gas inlet for introducing a reaction gas therein, and an exhaust system (not shown) is also connected to the reaction chamber 4.

Next, the operation will be described.

First, gas having the same flow rate, such as O ₂ or N _2, is introduced into the plasma chambers 11 and 12 through the gas introduction ports 11a and 12a. The electromagnetic coils 3 and 3 provided around the plasma chambers 11 and 12
Energize a so that the magnetic flux density of each plasma chamber 11 and 12 is 875 Gauss. Next, T-branch 20 and each waveguide 21, 22
A frequency of 2.45 at a ratio of 1: 1 to each plasma chamber 11, 12 through
Introduce microwave of GHz. Due to such conditions, 8
The frequency of the electrons rotating by the 75 gauss magnetic field and the microwave frequency of 2.45 GHz match, causing electron cyclotron resonance. Therefore, the electrons efficiently absorb energy from the microwaves, and high-density plasma is generated at a low gas pressure. Then, this plasma is drawn out along the lines of magnetic force of the divergent magnetic field formed by the electromagnetic coils 3 and 3a, and becomes two symmetrical plasma flows P as shown by broken lines in the figure.

Then, for example, a reaction gas such as SiH ₄ is introduced into the reaction chamber 4,
When the plasma flow stabilizes when observed from the outside, each shutter
Release 71 and 72. The plasma drawn into the reaction chamber 4 as described above reacts with the reaction gas, and this reaction material is accelerated in the direction of the divergent magnetic field and reaches the substrate 5 to form a Si oxide film or a Si nitride film. Is deposited. Here, the surface of the substrate 5 is covered with the deposition-inhibiting cover 6, so that the reaction substance is attached to the substrate 5 only through the opening 6 a of the deposition-inhibiting cover 6. This opening 6a, as described above,
It is formed so as to correspond to the portion where the plasma flow is always uniformly applied to the substrate 5. Note that the substrate 5 needs to be transported slowly in order to deposit a film having a predetermined film thickness in one transport, but the film quality is deteriorated by the film deposition on the substrate 5 by radicals. Therefore, the substrate 5 reciprocates at a speed at which film formation by radicals can be ignored (left-right direction in the figure), and as a result, the film is uniformly attached to the entire surface of the substrate 5 without degrading the film quality. .

In this embodiment, since two plasma chambers are provided and the film is formed by using the plasma flows from these plasma chambers, it is possible to irradiate the plasma flow onto a large area substrate and further Along with the movement, an anti-adhesion cover is provided in the vicinity of the substrate, and the film is formed only in a portion that is always irradiated with a uniform plasma flow. Therefore, a uniform film can be formed over a wide range.

Further, the plasma flow is a flow from the lower side to the upper side, and since the substrate is provided above the plasma chamber,
A deposit adhered to the deposition preventive cover or the like does not drop on the substrate, and a good quality film can be formed. Further, since the substrate is provided above, the substrate can be more easily transported during continuous in-line film formation as compared with a horizontal type apparatus in which a plasma chamber and a reaction chamber are arranged in the lateral direction.

Furthermore, since T branch 20 is used when introducing microwaves into the plasma chambers 11 and 12, the same energy can be introduced into the plasma chambers 11 and 12. A plasma flow having the same density can be derived from the plasma chambers 11 and 12, and the film formation can be made more uniform.

It should be noted that although the case where two plasma chambers are provided is shown in the above-mentioned embodiment, the number of plasma chambers is not limited to two, and may be arbitrarily determined according to the required size.

Further, although the plasma chamber is installed below the reaction chamber in the above-mentioned embodiment, it may be installed beside the reaction chamber or above the reaction chamber.

〔The invention's effect〕

As described above, according to the present invention, in the ECR plasma CVD apparatus, a plurality of plasma chambers are provided, an adhesion preventive cover having an opening is provided in the vicinity of the substrate, and the substrate is reciprocally moved from the plurality of plasma chambers. Since the film is formed by using the plasma flow of the above, only the uniform plasma flow over a large area is always radiated to the entire surface of the substrate through the opening of the deposition-inhibiting cover, so that the large area can be uniformly irradiated. There is an effect that various films can be formed.

[Brief description of drawings]

FIG. 1 is a sectional configuration diagram of a plasma deposition apparatus according to an embodiment of the present invention, and FIG. 2 is a partial plan view thereof. 11,12 ... Plasma chamber, 20 ... T branch, 21,22 ... Waveguide, 3,3a ... Electromagnetic coil, 4 ... Reaction chamber, 5 ... Substrate,
6 ... Adhesive cover, 6a ... Opening.

Claims (1)

[Claims] 1. A plasma chamber for introducing a microwave and a gas for generating a plasma and for generating a plasma therein, a reaction chamber for introducing a reaction gas, and a substrate for forming a film therein, A magnetic circuit disposed around the plasma chamber, wherein the magnetic circuit forms a magnetic field in the plasma chamber that satisfies an electron cyclotron resonance condition to generate plasma, and draws out the plasma flow to cause the plasma flow on the substrate. In the plasma deposition apparatus adapted to irradiate the substrate, a plurality of plasma chambers surrounded by the magnetic circuit are provided, a substrate in the reaction chamber is movably provided, and a substrate is provided near the substrate between the plasma chamber and the substrate. ,
A plasma deposition apparatus comprising a deposition preventive cover having an opening.