JPH0340422A - Film formation device - Google Patents

Abstract

PURPOSE:To improve the evenness of filming rate and filming quality by periodically changing the magnetic field impressed on a plasma production chamber. CONSTITUTION:After exhausting the air in a plasma production chamber 1 and a film deposition chamber 2 from an exhaust pipe 9 at the pressure of 5X10<-5>Pa, e.g. O2 as plasma production gas is led in from a gas leading-in port 3. Next, a magnetic coil 10 is impressed with a magnetic field by supplying it with power so as to produce high density oxygen plasma. The positions showing the flux density meeting the electronic cyclotron requirements are changing periodically within the range of 4-12cm from a plasma leading out window 12. E.g. SiH4 gas as a reaction gas is led-into the film deposition chamber 2 at the pressure of 5X10<-2>Pa. Through these procedures, the magnetic field impressed on the plasma production chamber 1 is periodically changed so that the evenness of filming rate and film quality may be notably improved thereby enabling the filming rate to be accelerated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a film forming apparatus that utilizes high-density plasma generated by electron cyclotron resonance.

(Prior Art) Plasma vapor deposition (plasma CVD) is widely used as one of the methods for forming thin films in semiconductor manufacturing processes. Furthermore, lowering the temperature of film formation.

A CVD method using ECR (electron cyclotron resonance) plasma is also known, which aims to increase the speed. A film forming apparatus using ECR plasma has conventionally had a configuration as shown in FIG. 2. Plasma is generated in the plasma generation chamber 21 by microwave excitation, but at the same time time is applied by the magnet coil 30, and high-density plasma is generated in a region within the plasma generation chamber 21 that satisfies the electron cyclotron resonance conditions. , 2.45G)l
For the microwave of z, the magnetic flux density that satisfies this electron cyclotron condition is 875 Gauss. The magnetic field generated by the magnet coil 30 is a so-called diverging magnetic field whose intensity decreases in the direction of the substrate 26, so that the high-density plasma generated in the plasma generation chamber 21 is drawn out toward the substrate and introduced into the film deposition chamber 22. A film is formed on the substrate 26 by reacting with the reactant gas.

However, in the conventional film forming apparatus using ECR plasma, the density of the plasma extracted by the divergent magnetic field of the magnet coil 30 provided around the plasma generation chamber 21 is different between the central part and the peripheral part of the plasma, There was a problem in that the film speed and film quality were significantly different between the center and the periphery of the substrate.

(Problems to be Solved by the Invention) As mentioned above, in conventional film forming apparatuses that extract plasma using a simple divergent magnetic field, the film forming rate and I! ! There has been a problem in that the quality of the film differs greatly between the center and the periphery of the substrate.An object of the present invention is to improve the film formation rate and the uniformity of the film quality.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention provides a film forming apparatus using OCR plasma in which the magnetic field applied to the plasma chamber is periodically changed. Features.

(Function) The density, traveling direction, and energy of electrons and ions extracted from the plasma generation chamber and reaching the substrate have a large effect on the film formation rate and film quality of the deposited film.

Therefore, by periodically changing the magnetic field applied to the plasma chamber, the density, traveling direction, and energy of electrons and ions reaching the substrate can be made uniform over the entire surface of the substrate, thereby improving the deposition rate and film quality of the substrate. In-plane uniformity is improved.

(Example) An example of a film forming apparatus according to the present invention will be described with reference to FIG. The vacuum chambers are plasma generation chamber 1 and film deposition chamber 2.
The plasma generation chamber 1 is connected to a gas inlet 3 for introducing plasma generation gas and a microwave waveguide 5 for introducing microwave power from a microwave power source 4. . I! Inside the deposition chamber 2, there is a substrate holder 7 for installing a substrate 6, and also a gas inlet 8 for introducing a reaction gas and a gas exhaust port 9 for evacuation to a vacuum.

Further, a magnet coil 10 for applying a magnetic field is provided around the plasma generation chamber 1, and a DC power source 13 and a 120 Hz AC power source 14 are connected to the magnet coil.

Next, a method of forming a silicon oxide film using the film forming apparatus shown in the above embodiment and the effect of improving the uniformity of Sa will be explained. First, the plasma generation chamber 21 and the film deposition chamber 2
After the tube No. 2 is evacuated to 5X10'''' Pa, a plasma generation gas such as No. 1 gas is introduced from the gas introduction port 3 at a flow rate of 40 cc/win.

Then, the magnet coil 10 provided around the plasma generation chamber is energized to apply a magnetic field, and a microwave power of, for example, 300V is applied to generate high-density plasma of oxygen.The generated plasma is caused by the divergent magnetic field. It is pulled out and reaches the board.

At this time, the position in the plasma chamber having a magnetic flux density that satisfies the electron cyclotron conditions periodically changes from 4cffl to 12c11 from the plasma extraction window 12. Further, as a reaction gas, for example, SiH4 gas is introduced into the film deposition chamber at a flow rate of 25 cc/win. At this time, the pressure in the film deposition chamber was 5×10 −″Pa.

When a silicon oxide film is deposited on a 6-inch silicon wafer for 3 minutes in this state, the film thickness is the thickest (Tmax
) 4600℃, 425 at the thinnest point (Twin)
λ, uniformity of film formation rate ((Tmax-Twin)/(
Tmax+Twin) is 4.0%, the refractive index is 1.472 at the largest point (Dmax), 468 at the smallest point (5 min), and the uniformity of the refractive index ((Dmax=
Dmin)/(Dmax+Dmin)) is 0.14%
Met. On the other hand, when the film is deposited using the film forming apparatus shown in Figure 2, Tmax is 3800 people and Twin is 34.
00 people, Dvaax is 1.473, Dmin is 1.4
64, the uniformity of film formation rate was 5.6% and the uniformity of refractive index was 0.31%. As described above, when the magnetic field applied to the plasma chamber was changed periodically, the film formation rate and in-plane uniformity of film quality were significantly improved, and the film formation rate also increased by about 12%.

The present invention is not limited to the above embodiments.

This method is also effective when the film to be deposited is another insulating film such as a silicon nitride film or a metal film, and is also effective when applying a bias voltage to the substrate. Also,
It is also effective when changing the frequency of the current flowing through the magnet coil.

〔Effect of the invention〕

As described above, according to the present invention, in film deposition using ECR plasma, the film formation rate and uniformity of film quality are significantly improved, and the film formation rate can be further increased.

[Brief explanation of drawings]

FIG. 1 is an apparatus configuration diagram showing an embodiment of the present invention, and FIG. 2 is an apparatus configuration diagram showing a conventional example. 1.21...Plasma generation chamber 2,22...Film deposition chamber 3.23...Gas inlet (plasma generation gas) 4
．． 24... Microwave power supply 5.25... Microwave waveguide 6, 26... Substrate 7.27... Substrate holder 8.28... Gas inlet (reaction gas) 9.29.・
・Gas exhaust port 30... Magnet coil 31... Electron and ion flux 32... Plasma extraction window

Claims (2)

[Claims] (1) comprising a plasma generation chamber in which plasma is formed by microwave excitation, applying a magnetic field to the plasma generation chamber;
In a film forming apparatus that generates high-density plasma by electron cyclotron resonance and draws the plasma to a film deposition chamber to form a film on a substrate by divergence of a magnetic field applied to a plasma generation chamber, the magnetic field applied to the plasma generation chamber is A film forming apparatus characterized by having a means capable of changing periodically. (2) The film forming apparatus according to claim 1, wherein the means for periodically changing the magnetic field applied to the plasma chamber causes a current containing an alternating current component to flow through the magnet coil.