JPH0252855B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to semiconductor circuit manufacturing equipment, and in particular, to plasma etching, plasma CVP, plasma ashing,
The present invention relates to a plasma processing apparatus that utilizes plasma, such as plasma direct nitride film formation.

[Prior art]

As the plasma in this conventional device, non-magnetized plasma to which no magnetic field is applied is mainly used. Further, as a device that applies a magnetic field, there is electron cyclotron resonance (hereinafter abbreviated as ECR) plasma in a linear magnetic field.

The conventional plasma generation method is to reduce the pressure of a vacuum container without applying an external magnetic field using a vacuum pump, introduce plasma generation gas into the container at an appropriate pressure and flow rate, and then place the plasma inside or outside the container. Plasma is generated by applying high-frequency power to an antenna such as a coil or parallel plate electrode. Charged particles, free radicals, etc. generated by this plasma react physically and/or chemically with the surface of the semiconductor substrate placed in the container, thereby obtaining the desired effect.

Other methods of generating plasma include direct current discharge and ECR discharge.
In addition, in order to eliminate the reaction of charged particles with the substrate surface, some devices use a metal mesh or the like to block plasma and prevent charged particles from flowing into the reaction region.

Conventional plasma processing apparatuses are as described above, and it is not easy to control plasma, and it is not possible to selectively react reactive particles (eg, cations and free radicals) with a semiconductor substrate. Furthermore, it is difficult to control the potential of the plasma on the surface of the semiconductor substrate. This has resulted in drawbacks such as damage to the substrate due to collisions with charged particle electrons and dielectric breakdown due to charge build-up during the formation of the insulating film.

[Summary of the invention]

The present invention was made in order to eliminate the above-mentioned drawbacks of the conventional method, and by utilizing plasma in a simple toroidal magnetic field, plasma can be easily controlled, and charge up on the surface of a semiconductor substrate can be prevented. Another object of the present invention is to provide a semiconductor circuit manufacturing apparatus that can selectively react positive ions, negative ions, electrons, or neutral particles such as free radicals with a semiconductor substrate.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In the figure, 1 is a torus-shaped vacuum container, and an angular duct 1a extending upward, downward, and outward from the container 1 is connected to a semiconductor substrate, etc. The port 1a also serves as a microwave supply means for supplying microwave power to the container 1 to generate plasma. 2 is a toroidal coil that generates a toroidal magnetic field; 3 is a vertical magnetic field coil that generates a perpendicular magnetic field perpendicular to the plane containing the torus;
4 is a core of a transformer that generates an alternating current electric field along the torus 1 by electromagnetic induction and applies the electric field to plasma; 5 is a primary winding of the transformer; 6 is a manipulator that holds a semiconductor substrate; 7 is a semiconductor substrate;
is plasma.

Next, the operation will be explained. The torus-shaped vacuum vessel 1 is placed in a high vacuum (approx.
10 ^-8 Torr). Furthermore, hydrogen glow discharge removes oxygen, carbon, etc. from the surface and cleans it. Further, the inner surface of the vacuum vessel 1 is coated with a sputter-resistant and reaction-resistant material such as titanium nitride to prevent sputtering and reactions caused by plasma. Next, a gas for plasma generation is introduced into the vacuum container 1. Next, a current is applied to the toroidal coil 2 to generate a toroidal magnetic field. Next, microwaves generated by a high-power magnetron or the like are introduced into the vacuum vessel 1 from one of the ports. When the frequency of the incident microwave matches the electron cyclotron resonance (ECR) frequency caused by the toroidal magnetic field, plasma 8 is generated within the torus-shaped vacuum vessel 1. The density of this plasma and the electron temperature are controlled by the incident microwave power and gas pressure. Further, the diameter of the plasma is controlled by an orifice provided on the inner wall of the torus-shaped vacuum vessel 1 or inside the vessel 1. The semiconductor substrate 7 is placed in the vacuum container 1 using a load lock or the like without bringing the entire container 1 to atmospheric pressure.
and is held by the manipulator 6.

A feature of the present invention is that it utilizes the drift motion of plasma particles in a simple torus-shaped magnetic field configuration. In this magnetic field configuration, the bending of the magnetic field lines,
Due to the effect of the gradient of the magnetic field strength and the gradient of the magnetic field strength, the charged particles undergo a so-called toroidal drift as shown in FIG. Since the direction of this drift is reversed depending on the sign of the charge on the particles, the plasma is polarized vertically, thereby generating an electric field in the vertical direction. The so-called E→ due to this electric field and toroidal magnetic field
Due to xB→drift, charged particles drift toward the outside of the torus at the same speed, regardless of the sign of charge, mass, etc. Since the positively charged particles 10 and the negatively charged particles 9 are incident on the outer wall of the torus with the same velocity, the so-called sheath that inevitably occurs in conventional plasma generation methods is almost completely generated. do not have. This prevents damage to the substrate caused by particles accelerated by the electric field of the sheath, and also prevents charge-up caused by charged particles gathering on one side. Furthermore, in a process in which charge up can be ignored, it is possible to selectively react either negatively charged particles or positively charged particles with the semiconductor substrate by placing semiconductor substrates above and below the torus container.

It is also known that by applying a vertical magnetic field to the plasma using the vertical magnetic field coil 3, the polarized charges are short-circuited by the electron flow along the magnetic field lines, reducing the vertical electric field and thereby reducing the radial plasma flow. It is being By utilizing this phenomenon, it becomes possible to control the plasma flow rate to the semiconductor substrate surface. Further, by applying an alternating current electric field to the plasma using the transformers 4 and 5, it is possible to increase the plasma density. Furthermore, by using both the increase and decrease of microwave power and the alternating current electric field, it becomes easy to control various plasma quantities, and it becomes easy to adapt the method to various semiconductor circuit manufacturing processes.

In this way, in this embodiment, it is possible to prevent charge up on semiconductor substrates placed outside the torus-shaped vacuum vessel, and it is possible to prevent charged particles from occurring on semiconductor substrates placed above and below the vacuum vessel. It is possible to react selectively depending on the charge. Also, plasma control becomes easier.

In the above embodiment, a case has been described in which plasma is generated in the torus by the ECF method, but RF discharge or CD discharge may also be used, and the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the semiconductor circuit manufacturing apparatus according to the present invention, plasma generated in a simple toroidal magnetic field is utilized, so that no charge up is caused to the semiconductor substrate placed outside the toroidal vacuum container. It is possible to prevent this, and it is possible to selectively cause charged particles to react with the semiconductor substrates placed above and below depending on their charges, and the plasma can be easily controlled.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a semiconductor circuit manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 is a conceptual diagram showing the movement of plasma particles in a simple toroidal magnetic field. DESCRIPTION OF SYMBOLS 1... Torus-shaped vacuum container, 1a... Square duct (microwave supply means), 2... Toroidal coil, 3
...Vertical magnetic field coil, 4... Core of transformer, 5... Primary winding of transformer, 6... Manipulator, 7...
Semiconductor substrate, 8... Plasma, 9... Negatively charged particles, 10... Positively charged particles. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A semiconductor circuit manufacturing apparatus using plasma, which includes a simple torus-shaped vacuum vessel, a coil that forms a vertical DC magnetic field within the vacuum vessel, and a plasma generated by supplying microwaves into the vacuum vessel. A semiconductor circuit manufacturing apparatus comprising: a microwave supply means for generating microwaves; and a transformer for applying an alternating current electric field to the generated plasma. 2. The semiconductor circuit manufacturing apparatus according to claim 1, wherein various quantities of plasma can be controlled by controlling the intensity of the vertical DC magnetic field, microwave, or AC electric field.