JPS611024A - Manufacturing apparatus of semiconductor circuit - Google Patents

Abstract

PURPOSE:To readily control a plasma, to prevent the surface of a semiconductor substrate from charging up and to selectively react charged particles or neutral particles by utilizing a plasma in a pure torus magnetic field. CONSTITUTION:A torus vacuum vessel 1 is evacuated in high vacuum, and purified by the glow discharge of hydrogen. Gas for generating a plasma is fed into the vessel 1, and a current is flowed to a toroidal coil 2 to generate a toroidal magnetic field. A microwave is incident from a port to the vessel 1, and when the frequency coincides with an electron cyclotron resonant frequency, a plasma 8 is generated. The diameter of the plasma is controlled by an orifice, a semiconductor substrate 7 is fed to a port without setting the entire vessel 1 to atmospheric pressure by using a load lock, and held by a manipulator 6. Accordingly, the plasma 8 can be readily controlled, it can prevent the surface of the substrate 7 from charging up and to selectively react charged particles and neutral particles.

Description

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

[Prior art]

As the plasma in conventional devices of this type, non-magnetized plasma to which no magnetic field is applied is mainly used. Further, as a device for applying a magnetic field, there is an 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. The charged particles, free radicals, etc. generated by this plasma are placed in the container and react physically and/or chemically with the surface of the semiconductor substrate, 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. For this reason, there have been drawbacks such as damage to the substrate due to collisions of charged particles and dielectric breakdown due to the charge amplifier during 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. By using plasma in a simple torus-shaped magnetic field, plasma can be easily controlled and charge-up on the surface of a semiconductor substrate can be prevented. It is an object of the present invention 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. 1st
The figure shows one embodiment of the present invention. In the figure, 1 is a torus-shaped vacuum vessel, and a square duct 1a extending upward, downward, and outward from the vessel 1 is used to carry a semiconductor substrate or the like into the vessel 1. The boat 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 an alternating current electric field along the torus 1 that is generated by electromagnetic induction; and this electric field is applied to the plasma. 5 is the primary winding of the transformer; 6 is a manipulator that holds the semiconductor substrate; 7
8 is a semiconductor substrate, and 8 is a plasma.

Next, the operation will be explained. The torus-shaped vacuum vessel 1 is kept under high vacuum (approximately 1O-8 Torr) to increase the purity of plasma.
). Furthermore, hydrogen glow discharge removes oxygen, carbon, etc. from the surface and cleans it.

In addition, the inner surface of the vacuum container 1 is sputtered by plasma,
To prevent reactions, etc., use spatter-resistant materials such as titanium nitride.
, coated with a reaction-resistant material. Next, a gas for plasma generation is introduced into the vacuum container 1.

Next, a current is passed through the toroidal coil 2 to generate a toroidal magnetic field. A zero-order microwave generated by a high-power magnetron or the like is input into the vacuum vessel 1 from one of the boats. 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 l.

The density of this plasma and the electron temperature are determined by the incident microwave power,
Controlled by gas pressure. Further, the diameter of the plasma is controlled by the inner wall of the torus-shaped vacuum vessel 1 or an orifice provided within the vessel 1. The semiconductor substrate 7 is introduced into the boat of the vacuum container 1 using a load rotor 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 charged particles undergo a so-called toroidal drift as shown in FIG. 2 due to the bending of the magnetic lines of force and the effect of the gradient of the magnetic field strength. 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.

Due to the so-called EXB drift caused by this electric field and toroidal magnetic field, charged particles are
Lift to the outside of the torus at the same speed. In this way, the positively charged particles 10 and the negatively charged particles 9 are incident on the outer wall of the torus at the same speed, so that the so-called sheath that inevitably occurs in conventional plasma generation methods is hardly generated. This prevents damage to the substrate caused by particles accelerated by the electric field of the sheath, and charge amplification caused by charged particles gathering on one side. In addition, in a process where charge-up can be ignored, by placing semiconductor substrates above and below the torus container, it is possible to selectively cause either negatively charged particles or positively charged particles to react with the semiconductor substrate.

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 toward the surface of the semiconductor substrate. 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, with the device of this embodiment, it is possible to prevent the semiconductor substrates placed outside the torus-shaped vacuum vessel from being charged, and it is possible to prevent the semiconductor substrates placed above and below the vacuum vessel from being charged. It is possible to cause particles to react selectively due to their 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 ECR method, but RF discharge or DC 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 torus magnetic field is used, so that the semiconductor substrate placed outside the torus-shaped vacuum container is not charged up. It is possible to prevent this, and it is possible to cause charged particles to selectively react with the semiconductor substrates placed above and below depending on their charges, and it is also possible to easily control the plasma.

[Brief explanation of the drawing]

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 vessel, 1a... Square duct (microwave supply means), 2... Toroidal coil, 3...
...Vertical magnetic field coil, 4...Transformer core, 5...
・Transformer primary winding, 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 (2)

[Claims] (1) A semiconductor circuit manufacturing apparatus that uses plasma includes a simple torus-shaped vacuum vessel, a coil that creates a vertical DC magnetic field within the vacuum vessel, and a microwave that supplies microwaves to the vacuum vessel to generate plasma. A semiconductor circuit manufacturing apparatus comprising a supply means and a transformer that applies 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.