JP2002158183A - Ion irradiation method and ion irradiation device - Google Patents

Abstract

(57) [Problem] To provide an ion irradiation method and an ion irradiation apparatus capable of reducing channeling. SOLUTION: In order to suppress channeling in ion irradiation, a magnetic field is applied to an ion incidence path from an ion generating part to a substrate 2, and ions are generated by Lorentz force proportional to the product of the velocity of the ions and the magnetic field. The ion implantation distribution is controlled by deflecting the substrate in the horizontal direction and implanting ions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion irradiation method and an ion irradiation apparatus used for doping impurities during ion implantation in a semiconductor process.

[0002]

2. Description of the Related Art In the process of manufacturing a semiconductor device, impurities are usually introduced by ion implantation in order to control electric characteristics of a semiconductor. When ions are implanted into a crystalline semiconductor substrate along the crystal axis of the substrate, a phenomenon called channeling occurs in which the ions penetrate deeply along the crystal axis.

FIG. 4 is a view for explaining the distribution of implanted impurities in a substrate when such a conventional channeling effect exists.

The depth of penetration of ions by channeling largely depends on the angle of incidence of ions, the temperature of the substrate, and the like, and is difficult to control. The ion implantation is performed at an angle to avoid channeling.

[0005]

As the device structure becomes finer and thinner, it becomes necessary to selectively introduce impurities into a shallow region near the surface. Various attempts have been made in addition to energy reduction. One of them is to ionize implanted impurities in plasma, accelerate ions in a sheath region generated between the plasma and the substrate, and implant the ions into the substrate.
There is a plasma doping technique. This plasma doping technique has the advantage that low-energy ions of several keV or less can be implanted at a high dose rate. However, since ions are accelerated by a sheath electric field, ions are implanted perpendicularly to the substrate, and channeling becomes apparent, and impurities are removed. Control of distribution may be impaired. Further, channeling becomes remarkable as the incident energy of ions decreases.

The present invention has been made in view of the above circumstances, and has as its object to provide an ion irradiation method and an ion irradiation apparatus capable of reducing channeling.

[0007]

According to the present invention, in order to achieve the above object, [1] In the ion irradiation method, in order to suppress channeling in the ion irradiation, the ion irradiation from the ion generating portion to the substrate reaches the substrate. A magnetic field is applied to the path, the ions are deflected in the horizontal direction of the substrate surface by Lorentz force proportional to the product of the velocity of the ions and the magnetic field, and the ion implantation distribution is controlled by ion implantation. [2] In the ion irradiation apparatus, in order to suppress channeling in ion irradiation, a magnetic field application region is provided in an ion incident path from the ion generating section to the substrate, and a Lorentz force proportional to the product of the ion velocity and the magnetic field Thereby, ions are deflected in the horizontal direction of the substrate surface and are implanted. [3] In the ion irradiation method, in order to suppress channeling in plasma doping, a magnetic field is generated on the surface of the semiconductor substrate using a magnet, and the ions are leveled on the substrate surface by Lorentz force proportional to the product of the ion velocity and the magnetic field. The ion implantation distribution is controlled by deflecting in the direction and performing ion implantation with the incident angle being equal to or greater than the channeling critical angle. [4] In the ion irradiation apparatus, in order to suppress channeling in plasma doping, a magnetic field is generated on the surface of the semiconductor substrate using a magnet, and the ions are leveled by the Lorentz force proportional to the product of the velocity of the ions and the magnetic field. The ion implantation is performed in such a manner that the light is deflected in the direction and the incident angle is set to be equal to or more than the channeling critical angle.

[0008]

Embodiments of the present invention will be described below in detail.

The ion beam irradiation apparatus of the present invention has means for controlling the angle of incidence of ions to be implanted into a semiconductor substrate by a magnetic field applied to the path of incidence of ions.

Further, according to a method of manufacturing a semiconductor device of the present invention, by using the above-described ion beam irradiation apparatus to suppress channeling of ions in a semiconductor substrate, an ion beam is provided by a magnet attached near a semiconductor substrate support. Is deflected, the ion incident angle is made larger than the critical channeling angle, and the channeling of ions in the substrate is suppressed, thereby controlling the impurity concentration distribution.

FIG. 1 is a schematic view of an ion beam irradiation apparatus showing an embodiment of the present invention.

In this figure, 1 is an incident ion, 2 is a substrate (sample), 3 is a substrate support, 4 is a permanent magnet, and 5 is a magnetic flux line.

As shown in FIG. 1, a permanent magnet 4 is installed near a substrate support 3 for supporting a substrate 2 to generate magnetic flux lines 5. That is, the magnetic field application region is provided on the incident path of the ions 1.

FIG. 2 is a diagram (partially enlarged sectional view as viewed from the direction A in FIG. 1) illustrating the deflection of ions by a magnetic field according to an embodiment of the present invention, showing magnetic flux lines and incident ion trajectories near the sample surface. ing.

In FIG. 1, reference numeral 11 denotes incident ions before deflection, 12 denotes magnetic flux lines, 13 denotes incident ions after deflection, and 14 denotes a substrate.

As shown in this figure, ions are deflected in the horizontal direction of the substrate surface by Lorentz force proportional to the product of the velocity of the ions and the magnetic field, and the ions are implanted at an incident angle equal to or greater than the channeling critical angle. At this time, if the magnetic field is changed with time by mechanically moving the magnet or reversing the magnetic pole, the effect of suppressing channeling becomes uniform on the substrate surface.

As a result, as schematically shown in FIG.
Impurities close to Gaussian distribution without channeling can be obtained.

The next-generation information communication / multimedia application equipment is expected to be compact, high-speed, and high-density, and accordingly, high-quality, short-term, and stable supply of semiconductor devices used in this equipment has become a proposition. I have. According to the present invention, the design of the manufacturing process of this semiconductor device can be realized by a method that is as clear as possible in principle, so that one of the basic technologies supporting the next-generation information communication and multimedia application industry is provided. be able to.

It should be noted that the present invention is not limited to the above embodiment, but various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0020]

As described in detail above, in the manufacturing process of a semiconductor device, ion irradiation is performed in plasma doping for introducing impurities for controlling electric characteristics of a semiconductor, ion assisted etching for fine processing, and the like. Will be applied. When ions are implanted into a crystalline semiconductor substrate along the crystal axis of the substrate, channeling occurs, and the depth of penetration due to the channeling greatly depends on the incident angle of the ions, the temperature of the substrate, and the like, and is difficult to control. However, according to the present invention, channeling in ion irradiation can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic view of an ion beam irradiation apparatus showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating deflection of ions by a magnetic field according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating an implanted impurity distribution in a substrate obtained by suppressing channeling according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating a distribution of implanted impurities in a substrate when a conventional channeling effect exists.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Incident ion 2, 14 Substrate (sample) 3 Substrate support 4 Magnet 5, 12 Magnetic flux line 11 Incident ion before deflection 13 Incident ion after deflection

Claims (4)

[Claims] In order to suppress channeling in ion irradiation, a magnetic field is applied to an ion incidence path from an ion generating section to a substrate, and ions are generated by Lorentz force proportional to a product of the velocity of the ion and the magnetic field. An ion irradiation method characterized by controlling the ion implantation distribution by deflecting in the horizontal direction of the substrate surface and implanting ions. 2. A magnetic field application region is provided in an ion incident path from an ion generating section to a substrate to suppress channeling in ion irradiation, and a Lorentz force proportional to a product of the velocity of the ion and the magnetic field is used. An ion irradiation device comprising means for deflecting the substrate in a horizontal direction of the substrate surface and implanting ions. 3. In order to suppress channeling in plasma doping, a magnetic field is generated on the surface of the semiconductor substrate using a magnet, and ions are deflected in the horizontal direction of the substrate surface by Lorentz force proportional to the product of the ion velocity and the magnetic field. An ion irradiation method characterized by controlling the ion implantation distribution by performing ion implantation at an incident angle equal to or greater than a channeling critical angle. 4. In order to suppress channeling in plasma doping, a magnetic field is generated on the surface of the semiconductor substrate using a magnet, and ions are deflected in the horizontal direction of the substrate surface by Lorentz force proportional to the product of the velocity of the ion and the magnetic field. An ion irradiating apparatus, comprising: means for performing ion implantation with the incident angle being equal to or greater than the channeling critical angle.