JPS6186410A - Vitreous carbon filament - Google Patents

Abstract

PURPOSE:To prepare the title filament having high strength, high hardness and high abrasion resistance, and corrosion resistance being useful in atmosphere at high temp. by treating filaments prepd. by extruding a kneaded material consisting primarily of chlorinated PVC with carbon precursor and then calcining in inert gas atmosphere. CONSTITUTION:A mixed compsn. consisting primarily of chlorinated PVC (pref. 60-71wt% chlorine content) is dispersed and milled, and obtd. mixture is extruded to filaments, and treated with carbon precursor, and calcined thereafter in an inert atmosphere. By the calcination, vireous carbon filament having >=400 MPa bending strength and 0.1-1.0mm dia. with a uniform compsn. are obtd. The vitreous carbon filament has high strength, high hardness and high abrasion resistance being a useful material suited as filament in a corrosive atmosphere or hot atmosphere where metallic wire such as steel wire, stainless steel wire, tungsten wire, etc., has hitherto been unusable. The filament is particularly suited as an emitter material for implanting boron in the ion microbeam process.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a glassy carbon fine wire. Specifically, the present invention relates to a glassy carbon thin wire and a method for manufacturing the same. moreover,
The present invention relates to an emitter material for an ion microbeam source that utilizes the properties of the glassy carbon thin wire of the present invention.

(Prior art) Glassy carbon follows a solid phase carbon reaction.Thermosetting resins such as phenol formaldehyde resin, furfuryl alcohol resin, divinylbenzene styrene copolymer, cellulose, polyacrylonitrile, polyvinylidene chloride, etc. are heated in an inert atmosphere. It has a black glass-like appearance obtained by gradually increasing the temperature inside the glass, and the fractured surface has a shiny shell-like appearance similar to a glass fractured surface.It has high strength and hardness, and is extremely breathable. It is a carbon material with excellent characteristics such as small size.

However, with the conventional techniques, it is extremely difficult to industrially obtain thin glassy carbon wires having a diameter of 0.1 to 1.0 mm, which is the object of the present invention, at low cost. That is, when a thermosetting resin is used as a raw material, casting methods, extrusion molding methods, etc. are used as a molding method, but in general, the tensile strength and bending strength of the molded product are poor, and it is extremely difficult to mold a thin linear body. Even if it is thin, a rod-shaped body with a diameter of at most several TIII+ can be obtained. Therefore, the object of the present invention is 0, 1 to 1.
．． In order to obtain the fine wire of 01, it is possible to cut the molded product before firing or the carbide after firing, but this method not only requires extremely advanced technology, but also leaves fine particles on the surface of the cutting result. This is not a preferred method because racking occurs and causes a significant decrease in strength. Moreover, according to additional tests conducted by the inventor of the present application, the bending strength of a glassy carbon rod-like body with a diameter of 4 mm before cutting was as low as 100 MPa at most. On the other hand, polyacrylonitrile, cellulose derivatives,
Fibrous carbon, which is made of glassy carbon obtained by molding polyvinylidene chloride or phenol resin as a raw material into a fiber shape and then firing it, is well known, but it is relatively easy to mold these into a fiber shape. So, from a few μmm to more than ten μn
O++ fibrous carbon is obtained. However, it has not yet been possible to obtain a thin wire of 0.1 to 1.0 mm, which is the objective of the present invention, due to limitations in its formability and carbonizability.

Recently, with the increasing integration of semiconductor devices, the pattern width has tended to become narrower, and while fibrous carbon itself has extremely high strength, its diameter is too small to the point where it can be used alone, and ion microbeam technology has been developed. be. This is done by using a liquid metal as an ion source, for example, by sufficiently wetting the surface of a needle-shaped emitter material with a tip radius of curvature of several micrometers or less with metal liquefied at high temperature and applying a positive potential to the extraction electrode. This is a technology that applies the ionization and emission of metal atoms or molecules from the tip of an emitter. In order to be effectively used as an emitter material, it is required to have good chemical reaction resistance with the molten ion material, good wettability with the molten ion material, and good processability into needle shapes. Ru.

Conventionally, tungsten wire has been used as an emitter material for implanting potassium and indium. but,
Recently, attempts have been made to implant poron as a P-type impurity in silicon semiconductors, but since poron has a high chemical reactivity with metals at high temperatures, it is inappropriate to use tungsten wire as an emitter material because it causes a lot of wear and tear. . Therefore, carbon thread material is used as an emitter material for implanting Poron, but conventional carbon materials are obtained by molding and firing carbon filler using an organic binder, and the adhesive strength between the carbon filler and the binder carbon is Since the tip is not large enough, it is extremely difficult to process the tip to a size of several micrometers or less, and even if it can be processed into sheet metal, the strength of the tip is weak and does not exhibit sufficient characteristics as an emitter material. In view of the above points, a high-strength thin wire made of glassy carbon is considered to be the most effective material for the emitter material, but it has not yet been obtained industrially at a low cost using conventional techniques.

(Problems to be Solved by the Invention) The object of the present invention is to have a bending strength of 400 MPa or more and a diameter of 0.
．． The purpose of the present invention is to provide a thin glassy carbon wire of 1 to 1.0 mm with a uniform composition, and to provide a method for manufacturing such a thin glassy carbon wire industrially and inexpensively without using methods such as cutting. That's true.

A further object of the present invention is to provide an emitter material for an ion microbeam source made of the glassy carbon thin wire.

(Means for Solving the Problems) In order to achieve the above object, the inventor of the present application, as a result of intensive research, mixed and dispersed and kneaded a blended composition containing chlorinated vinyl chloride resin as a main component, and then It was discovered that a glassy carbon thin wire could be obtained by extrusion molding the obtained kneaded product into a fine wire, subjecting the molded product to a carbon precursor treatment, and then firing it in an inert atmosphere. Reached.

The chlorinated vinyl chloride resin defined in the present invention refers to a vinyl chloride resin that has a chlorine content of 60% by post-chlorination.
-70 x resin, and its degree of polymerization is 500-1500. If the resin has a chlorine content lower than 60Wt2, the strength of the glassy carbon thin wire obtained after firing will be low;
A resin having a value larger than χ is undesirable because of poor extrusion moldability. Considering the balance between the strength of the glassy carbon thin wire and the extrudability, it is preferable to use a resin having a chlorine content of 63 to 70 Wtχ. Further, one type or two or more types of resins within the above range may be blended. Chlorinated vinyl chloride resin can be extruded alone, but the softening temperature of the resin and the deterioration temperature mainly caused by dehydrochloric acid reaction are close to each other, and depending on the type of extrusion molding machine, the shearing force may be large. There are some models in which shearing force is applied, and the deterioration of the resin is accelerated by shearing force.
More favorable results are obtained when plasticizers and molding aids are added to the formulation to improve the extrusion time.

Plasticizers that are commonly used for vinyl chloride resins can be used, such as dioctyl phthalate, dibutyl phthalate, tricresyl phosphate, dioctyl adipate, dioctyl sebacate, diallyl phthalate monomer, propylene carbonate, N-methylpyrrolidone, etc. One or more types of propylene carbonate are added to the blended composition in an amount of 3 to 60 WtX, and preferably propylene carbonate is added in an amount of 5 to 50 WtX to the blended composition to exhibit good extrusion moldability.

As with the plasticizer, molding aids that are commonly used for vinyl chloride resins can be selected, such as chlorinated polyolefins, ethylene-vinyl acetate copolymers, and ethylene-vinyl acetate copolymers.
One or more types of acrylic copolymers, metal soaps, aliphatic amide soaps, natural waxes, petroleum waxes, organic tin compounds, etc. are added to the 0.1 to 10 Wtχ blended composition, preferably aliphatic amide. Stone Ken 0.1~2
．． Addition of 0 Wtχ not only exhibits good extrusion moldability, but also increases the strength of the glassy carbon thin wire obtained after firing.

Next, a method for manufacturing a glassy carbon thin wire using the above raw material will be explained.

Chlorinated vinyl chloride resin 35-100Wtx, preferably 45-85wtz, plasticizer 0-60Wt! A blended composition consisting of a molding aid of 0 to 10111 tz, preferably 0.1 to 2.0 Wt.chi. is weighed and thoroughly mixed using a high speed mixer such as a Henschel mixer. Next, if necessary, the mixture is kneaded under heating using a kneader such as a mixing roll or a pressurized kneader, and the kneaded product is used to create pellets for extrusion using a granulator. Kneading and granulating the blended composition are effective in degassing the molded product and preventing surging of the molded product in the subsequent extrusion molding process. Next, using a ram type extrusion molding machine or a screw type extrusion molding machine, 50 to 150
The die head is heated to .degree. C., and the carbon wire is extruded to a diameter of 0.2 to 2 mm, depending on the diameter of the desired carbon wire, and cut to a desired length to obtain a desired molded product. Next, most of the plasticizer used in the molded product is evaporated by heating in the air or under reduced pressure, and then a carbon precursor treatment is performed. This carbon precursor treatment method is carried out in an oxidizing atmosphere such as air or ozone.
A method of heat treatment from 0 to 300°C, a method of heat treatment from 50 to 300°C in a corrosive gas atmosphere such as ammonia gas or chlorine gas, a method of immersion in a strong acid such as concentrated sulfuric acid,
There are methods such as irradiation with radiation. In the present invention, the method of carbon precursor treatment is not particularly limited. Next, the carbon precursor-treated molded product is gradually heated in an inert atmosphere such as nitrogen or argon to 700°C or higher, preferably 1000°C or higher, and after cooling, it is taken out and made into a high-strength glass. Obtain a shaped carbon thin wire.

The high-strength glassy carbon thin wire obtained by the above operation is cut to a desired length, the tip is processed to have a radius of curvature of several μm or less, preferably 3 μm or less, and is used as a sputtering material for ion microbeams. do.

Processing methods for the tip include mechanical polishing using silicon carbide powder, alumina powder, or diamond powder, chemical polishing by dipping in hydrofluoric acid,
There is a method of electrolytically polishing the glassy carbon thin wire using a mixed acid solution or molten salt as an electrolyte and using it as an anode electrode, but in the present invention, the method for processing the tip is not particularly limited, and it can be modified as necessary. The above methods may be combined as appropriate.

(Effects of the Invention) The glassy carbon thin wire of the present invention has excellent performance such as high strength, high hardness, and high wear resistance, and has excellent properties such as high strength, high hardness, and high wear resistance. It is a useful material that cannot be obtained by conventional methods as a wire rod in corrosive atmospheres, high-temperature atmospheres, etc., where metal wires cannot be used. In particular, boron bombardment that dissolves in the ion microbeam method.

It can be said to be the best material for emitter material for chikomi.

Next, the present invention will be specifically explained using examples.

A blended composition consisting of a chlorinated vinyl chloride resin with a chlorine content of 65WtX [Nikatemp T-742380Wtx manufactured by Nippon Carbide ■, propylene carbonate 19xx, and stearic acid amide 1xx] was thoroughly prepared using a Henschel mixer. After mixing and dispersing and kneading the mixture under heating at 130° C. using a processing kneader, the kneaded product was taken out and a pellet for extrusion molding was obtained using a pellet making machine. Next, the die head was heated to 125° C. and extrusion molded using an axle screw extrusion molding machine to obtain a molded product having a diameter of 0.8 mm. This molded product was cut into lengths of 20 cm, most of the propylene carbonate was evaporated in a heated oven at 150°C under tension, and then the temperature was raised to 180°C at a rate of 5°C/.
Carbon precursor treatment was carried out by holding at 180° C. for 60 hours. After that, in a nitrogen gas atmosphere, from room temperature to 300℃, 10℃/h, from 300 to 600℃, 30℃/h, 600℃
Carbonization treatment was carried out by heating at a rate of 100°C/h up to 1000°C, and the product was taken out after cooling. The diameter of the obtained glassy carbon thin wire was 0.35 m1. The bending strength showed a high value of 750 MPa.

1 Chlorinated vinyl chloride resin with a chlorine content of 68% (Nihon Carbide Nippon Carbide T~781) 75Wtχ,
Propylene carbonate 24 χ, oleic acid amide I
A blended composition consisting of WtX was sufficiently mixed and dispersed using a Henschel mixer, and kneaded using a processing kneader while heating at 135° C. The kneaded product was taken out and a pellet for extrusion molding was obtained using a pellet making machine. Next, the die head was heated to 130° C. and extrusion molded using an axle screw extrusion molding machine to obtain a molded product having a diameter of 1.8 mm. This molded product was cut into lengths of 20 cm, most of the propylene carbonate was evaporated in a heated oven at 150°C under tension, and then the temperature was raised to 180°C at a heating rate of 5°C/180°C. C. for 70 hours to perform carbon precursor treatment. Thereafter, carbonization treatment was performed by firing in a nitrogen gas atmosphere under the same conditions as in Example 1, and the product was taken out after cooling.

The diameter of the obtained glassy carbon thin wire was 0.80 mm, and the bending strength was as high as 650 MPa.

Tsugaran 9-1 The glassy carbon thin wire with a diameter of 0.81 obtained in Example 2 was cut to a length of about 10 mm, and the tip was roughly polished to a radius of curvature of about 0.05 mm using diamond powder paper powder. , hydrochloric acid treatment, and then anodic electrolytic treatment using a phosphoric acid-sulfuric acid mixture as an electrolytic solution, and the tip was electrolytically polished to a radius of curvature of about 2 μm. Next, the needle-shaped body obtained by the above operation was attached to an ion microbeam device as an emitter material, and boron was implanted into the silicon substrate using nickel boride as the ion material. The emitter material using the glassy carbon thin wire of the present invention has good wettability with the molten ion material, and the lifespan of the emitter material using conventional tungsten wire is at most 10 hours. Against, 3
It had a lifespan of over 00 hours.

Claims (1)

[Claims] 1) Bending strength of 400 MPa or more, diameter of 0.1 to 1.0
Glassy carbon thin wire with a uniform composition of mm. 2) After mixing, dispersing and kneading a blended composition containing chlorinated vinyl chloride resin as a main component, the resulting kneaded product is extruded into fine wires, and the molded product is subjected to a carbon precursor treatment and then A method for producing a glassy carbon fine wire comprising firing in an active atmosphere. 3) The chlorinated vinyl chloride resin has a chlorine content of 60 to 71W.
The method of the second term, where t%. 4) The method according to item 1, wherein the compounded composition comprises a chlorinated vinyl chloride resin as a main component and a plasticizer and/or a molding aid. 5) The blended composition contains propylene carbonate 5-50W
% of the plasticizer as a plasticizer. 6) The blended composition contains 0.1 to 2.0 of aliphatic amide soap.
7) The method of item 2, wherein the molding involves first producing pellets for extrusion molding, and then linearly extruding the pellets using a single screw extruder. 8) An emitter material for an ion microbeam source made by cutting the glassy carbon thin wire to a desired length and processing the tip to have a radius of curvature of several μm or less.