JPH09223675A - Carbon member for ion implantation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce sublimation wear upon exposed to an ion beam, and reduce damage of a member due to ion beams and scattered particles by using a carbon member for ion implantation apparatus, the member comprising a carbon fiber reinforced composite material yielded by laminating carbon fibers or graphitizing the fibers. SOLUTION: A laminated carbon fiber reinforced composite material is yielded by filling it with synthetic resin and a coal binder carbonized with heating and joining it with the synthetic resin and the binder, and then heating them to carbonize and graphitize the resin and pitch and rendering them to a heating and highly purifying processing with halogen containing gas. The carbon fiber reinforced carbon composite material 2 has a lower heat conductivity in the direction of the lamination compared with those in the direction of a perpendicular surface in the lamination direction. For this, once the material is exposed to an ion beam, thermal energy produced in the carbon is selectively dissipated in the direction of the perpendicular surface to the lamination direction to prevent the member from being raised in temperature. Further, a sublimation rate of the carbon is lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon member for an ion implantation apparatus used in a process of manufacturing a semiconductor device such as an LSI, and more specifically, a P member for a highly pure semiconductor wafer in a manufacturing process of a semiconductor integrated circuit.
Type and n-type impurities are added to a wafer and a doping process is performed, a carbon member for an ion implantation apparatus used for an ion implantation method that irradiates ions having kinetic energy to impart P and N characteristics, Specifically, carbon members used for vanes (shutters) such as extraction electrode systems, mass spectrometry systems, accelerator systems, Faraday systems (injection chambers), front plates, inserts, and apertures of ion implantation equipment used in the ion implantation process. Regarding

[0002]

2. Description of the Related Art There is an ion implantation process as a process for manufacturing a semiconductor device. This process is a method of ionizing a target element in a silicon substrate with high energy by an ion implantation method, accelerating and implanting it into a semiconductor substrate.
Particularly, it is important to prevent the mixture of a predetermined concentration, a driving depth, and impurities.

In the ion implantation method, ions such as B, P and As are used as introduced impurities in a silicon substrate.
It is widely used as a method with excellent controllability and reproducibility. Generally, thermoelectrons emitted from a filament in a magnetic field are used to generate ions, and an ion beam is usually several mA to several tens m at an accelerating voltage of several tens eV to several hundreds eV.
A, several tens of W to several kW of implantation conditions are used.

The ion implantation apparatus includes an ion source, an extraction unit for supplying energy, a mass analysis unit for selecting ions, an acceleration unit for accelerating ions, and a focusing unit for converging an ion beam.
It consists of a scanning unit that uniformly scans the silicon wafer with an ion beam, and an implantation chamber that injects ions into the wafer.These are materials that maintain high purity so that impurities other than Al do not mix during the operation process. It is configured.

Among them, members such as vanes, front plates, and inserts inside the ion implantation apparatus are made of high-purity graphite material which is excellent in heat resistance and does not pollute the wafer because it is exposed to a high-energy ion beam. ing. This carbon member for ion implantation equipment is used as a part by molding carbon powder or graphite powder with a binder, or baking and graphitizing a spherulite material, and purifying (deashing) the obtained graphite block. It was

[0006]

However, since this material is an aggregate of finely structured particles, fine particles are easily scattered when sputtered, and iron and calcium contained in a trace amount in graphite. , Vanadium and the like are mixed as impurities in the silicon wafer, and there is a problem that the performance of the product is deteriorated in the semiconductor manufacturing process in which a higher-purity product is required.

Therefore, an attempt has been made to cope with high integration of semiconductor devices by forming an ion implanting member with glassy carbon in which particles are less scattered by an ion beam (Japanese Patent Laid-Open No. 5-246703). However, glassy carbon has a drawback that it has a low thermal conductivity, cracks easily occur due to thermal shock and thermal stress, and that it is difficult to process.

Further, since these conventional carbon members for ion implanters have high isotropic properties, the ion beam (usually several mA to several tens mA at an accelerating voltage of several + eV to several hundred eV:
By irradiation of several tens of W to several kW), the kinetic energy of ions is converted into thermal energy on carbon, and the surface temperature is 1
The temperature rises to about 000 to 2300 ° C, and carbon evaporates and is consumed. Therefore, the thermal conductivity is 80 to 120 kca.
When a graphite material of 1 / mhr ° C. is used, there is a drawback that the peripheral part (in the direction of the thickness) evaporates and is consumed depending on the surface temperature.

As described above, the conventional member made of the graphite material has a large amount of sublimation consumption due to the rise of the surface temperature when exposed to the above-mentioned ion beam, and the carbon member for the ion implantation apparatus has reduced the sublimation consumption. Was desired to be developed.

Particularly in recent years, the use of implanters with high ion energy is increasing for the purpose of increasing the production throughput, and deterioration due to damage of members by the beam and scattering of particles into the system are improved. It is desired to provide a carbon member for an ion implantation device which is resistant to thermal shock and has a longer life.

The present invention was developed on the basis of the above-mentioned findings, and when it is exposed to an ion beam, sublimation consumption is small,
To provide a carbon member for an ion implantation device, which has a long life and is durable against thermal shock and thermal stress without the inclusion of impurities due to damage of the member due to the ion beam and scattering particles being reduced. With the goal.

[0012]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of earnest studies to solve the above-mentioned problems, if all or a main part of the ion-exposed device exposed to ions is composed of a laminated carbon fiber-reinforced carbon composite material, a high energy density is obtained. The present invention has been completed based on the finding that a carbon member for an ion implantation apparatus can be provided that can be applied to the ion beam irradiation described in (1) above and that the life can be doubled.

That is, carbon fiber woven fabrics are laminated, or carbon fiber bundles are laminated in one direction or in multiple directions, and then pitch, resin, etc. are impregnated to carbonize and graphitize to obtain a carbon fiber reinforced carbon composite material. Then, this is used for all or main parts of the ion-exposed device exposed to the ions.
Here, the woven fabric may be in any form such as felt, plain weave, satin weave, and twill weave.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A laminated carbon fiber reinforced carbon composite material is formed by laminating carbon fiber cloth, woven fabric, etc., and heating the fibers, interlayers, etc. by heating phenol resin, furfural resin, furan resin, divinylbenzene resin, etc. Carbonized synthetic resin or coal-based soft pitch, medium pitch, hard pitch,
It is obtained by filling and bonding with a binder such as petroleum pitch, heating at least 2500 to 3000 ° C. or higher to carbonize and graphitize the resin and pitch, and further heat and purify the resin and pitch with a halogen-containing gas. At this time, the obtained member had a thermal conductivity of 1 in the plane direction perpendicular to the stacking direction.
Those having a temperature of 50 kcal / mhr ° C. or higher are preferable in terms of action and effect.

The carbon fiber is preferably a graphitizable pitch-based or PAN-based (polyacrylonitrile-based) that is easily graphitized at 2000 ° C. or higher, and the binder is a non-graphitizable resin-based or hard pitch. Preferably. The resin and pitch contents are appropriately adopted within the range of 35 to 65% by weight.

In the carbon member of the present invention, the whole or at least the main part thereof is composed of the carbon fiber reinforced carbon composite material. However, when the part other than the main part is composed of another kind of material, high density isotropic graphite and / Or glassy carbon is desirable in terms of preventing particles from scattering into the system.
Further, it is also effective to coat the surface layer of the member with glassy carbon.

The high density isotropic graphite may have a bulk specific gravity of 1.8 or more and a thermal conductivity of about 80 to 120 kcal / mhr ° C. according to a conventional method, and a combination of this and the carbon fiber reinforced carbon composite material While exerting the effect of the main part, the manufacturing cost can be reduced and the product can be supplied at low cost without deteriorating the characteristics of the whole.

The glassy carbon is amorphous carbon which is obtained by molding a synthetic resin such as phenol or furan and then firing and carbonizing it. In combination with the glassy carbon, a particle scattering preventing effect can be particularly added.

Further, the glassy carbon coating is preferably formed by applying the above synthetic resin into a film and then applying, coating, or impregnating and coating it, followed by heating and carbonization to form a strong coating layer. It is preferable that all the isotropic graphite is subjected to a purification treatment before use.

The operation of the member of the present invention is as follows.
The carbon fiber reinforced carbon composite material has a lower thermal conductivity in the laminating direction than the thermal conductivity in the plane direction perpendicular to the laminating direction. Therefore, when exposed to an ion beam, the thermal energy generated in carbon is generated in the laminating direction. Heat is selectively dissipated in a plane direction perpendicular to the above to prevent the temperature of the member from rising and to reduce the sublimation rate of carbon.

Further, when it is exposed to an ion beam, sublimation and wear will progress, but since the thermal conductivity is relatively higher than that of the conventional graphite material, the temperature rise of the member is reduced due to heat dissipation, and the sublimation speed is increased. Is also lower than conventional graphite materials.

Even in the above case, the carbon fiber-reinforced carbon composite material of carbon fiber has a higher strength than conventional graphite materials, so that cracks and the like are less likely to occur, and the binding force between the fiber (filler) and the matrix is strong. Therefore, the number of particles is smaller than that of the conventional graphite material.

As described above, when the carbon member of the present invention is used, the life is about twice as long as that of the member using the conventional graphite material, and the amount of generated particles can be reduced by about 25%.

[0024]

【Example】

Examples 1 to 5 and Comparative Example 1 As a vane member for narrowing the beam extracted from the ion source head of the 1.2 kW ion implantation apparatus, FIG.
The vane member having the shape of 60 × 160 × 8 tmm shown in Table 1 was obtained from the materials shown in Table 1. For comparison, vane members having the same shape were made of isotropic graphite. Both members are manufactured by Applied Materials Japan, Inc., product name: P1-9200
They were attached to the device and their functional lives were compared.

As a result, the member of the present invention was found to have a life extension about twice as long as that of the conventional member made of isotropic graphite.

[0026]

[Table 1]

[0027]

EFFECTS OF THE INVENTION In the laminated-type carbon fiber reinforced carbon composite material of the present invention, even if the surface layer is heated by being exposed to an ion beam, heat is dissipated through the surface layer and acts adiabatically in the thickness direction. As compared with the surface layer, the temperature greatly drops, and the amount of carbon vaporized can be reduced. As a result, the sublimation consumption of carbon is reduced, the damage of the members due to the ion beam is reduced, and it is possible to provide a carbon member for the ion implanter with a longer life, the replacement cycle is extended, the maintenance interval of the ion implanter is extended, and the production efficiency is improved. Will also rise and the amount of used industrial waste generated will decrease. In addition, it is possible to provide a carbon member for an ion implantation apparatus, in which scattered particles are reduced, the cleanliness of the system is dramatically improved, impurities are not mixed, and workability is excellent.

[Brief description of drawings]

FIG. 1 is a perspective view of a vane in which a carbon fiber-reinforced carbon composite material of the present invention is used as a main part.

FIG. 2 is a perspective view of an aperture made of the carbon fiber reinforced carbon composite material of the present invention.

[Explanation of symbols]

 1 vane 2 carbon fiber reinforced carbon composite material 3 isotropic graphite or glassy carbon 4 aperture 5 window

Claims (3)

[Claims] 1. A carbon member for an ion implantation device, comprising a carbon fiber-reinforced carbon composite material obtained by laminating carbon fibers and carbonizing or graphitizing them. 2. A main portion of a portion exposed to an ion beam inside the ion implantation apparatus is composed of a carbon fiber reinforced carbon composite material obtained by laminating carbon fibers and carbonizing them, and the other portion is high density. A carbon member for an ion implantation device, which is composed of isotropic graphite and / or glassy carbon. 3. The carbon member for an ion implantation device according to claim 1, wherein the surface layer is coated with glassy carbon.