JP2003213412A - Method and device of plasma ion implantation and film forming - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device in which ions are implanted and/or a film is formed by using a plasma ion implantation method by which an element other than a target element and coarse particles are excluded. <P>SOLUTION: Plasma is generated from the vapor of an electrically conductive molten solution by discharge in which the molten liquid is used as a cathode, and ions in the plasma are implanted into a work to be processed by applying negative high voltage pulses on the work to be processed which is placed in the plasma. A film is formed when the voltage applied to the work to be processed is low. Further, it is possible that a vapor deposition with the vapor generated from the molten solution is performed simultaneously with the ion implantation. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ion implantation method,
The present invention relates to a film forming method and an ion implantation and / or film forming apparatus.

[0002]

2. Description of the Related Art Development of plasma ion implantation has been advanced as a new ion implantation and film forming technique. Plasma ion implantation is a general term for a technique of applying a negative high-voltage pulse to an object to be processed placed in plasma and injecting ions in the plasma to the surface of the object to be processed. If the conventional ion implantation method using an ion beam is used, it is easy to implant ions into a flat-shaped object such as a semiconductor wafer, but in the case of a three-dimensional object, it is injected by rotating it. However, some parts could not be injected depending on the shape. When plasma ion implantation is used, it can be implanted into the entire circumference of a three-dimensional object at one time, which makes it possible to expand the range of application and reduce the processing cost, and therefore it is drawing attention.

In the plasma ion implantation technique, when a solid element such as metal at room temperature is implanted as ions, it is necessary to generate plasma of the element. When plasma is generated by discharge using a chloride or organometallic compound gas, chlorine, carbon, hydrogen, etc. are simultaneously injected in addition to the target ions. When it is desired to implant only target ions, a method of directly generating plasma from a solid material using a vacuum arc discharge is used.

As a film forming technique having a form similar to that of the present invention, there is, for example, "JP-A-11-36073 Ion plating device". Pulse bias to substrate (Positive: 50 to 120V, Negative: -200
However, the purpose of using the pulse bias is to prevent charge-up that occurs when depositing an insulating substrate or an insulating material, and applying a negative high voltage pulse in the present invention. It is distinguished from the plasma ion implantation method.

[0005]

The vacuum arc discharge is used as described above to generate the plasma used for plasma ion implantation. However, the vacuum arc discharge using the solid raw material causes a "droplet (droplet)". ) ”Is generated, which is attached to the surface of the object to be treated. This phenomenon becomes a big problem when a flat treated surface is desired, and a technique for reducing droplets generated by vacuum arc discharge and a device for preventing the droplets from reaching the object to be treated as much as possible are made. However, it is difficult to completely remove the droplet.

[0006]

The present invention includes the following items 1 to 3.
Item 11 A method and an apparatus for performing ion implantation and film formation. Item 1. A method of applying a negative high voltage pulse to an object to be processed in plasma to perform ion implantation and / or film formation on the object to be processed, which is a melt or sublimation of a solid raw material as a material evaporation source used for plasma generation. A method characterized by using a thing. Item 2. Item 2. The method according to Item 1, wherein the solid raw material is a single element, an alloy thereof, or a compound capable of being vacuum-deposited. Item 3. Item 3. The method according to Item 2, wherein the compound capable of being vacuum-deposited is a semiconductor of an element simple substance, an organic semiconductor or a polymer semiconductor. Item 4. Item 2. The method according to Item 1, wherein the material evaporation source used for plasma generation is a melt of a solid raw material. Item 5. Item 2. The method according to Item 1, wherein the solid raw material is carbon. Item 6. Item 6. The method according to any one of Items 1 to 5, wherein plasma is generated in the presence of nitrogen gas and / or oxygen gas and / or hydrocarbon gas. Item 7. The method according to item 1, wherein a shield plate is present between the object to be processed and the melt or sublimate to perform ion implantation or film formation. Item 8. A device for applying a high voltage pulse to an object to be processed having a high voltage pulse power source and a support device for the object to be processed; a discharge device consisting of an anode, a cathode body capable of holding a solid raw material melt or carbon, and a power source for discharge; Apparatus for melting or sublimating the solid raw material or carbon; ion implantation and / or film forming apparatus equipped with a vacuum chamber. Item 9. Item 9. The apparatus according to Item 8, further comprising an inlet pipe for nitrogen gas and / or oxygen gas and / or hydrocarbon gas. Item 10. Item 9. An apparatus according to item 8, wherein a shielding plate is provided between the object to be processed and the material generation source. Item 11. Plasma ion implantation / deposition treatment product with no droplets on the surface to be treated and the ion implantation material being the only material evaporation source.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the embodiments shown in the drawings.

First, the solid raw material excluding carbon will be described.

As shown in FIG. 1, solid raw materials excluding carbon such as elemental elements or compounds are melted by electron beam heating or the like in a vacuum chamber evacuated. When the solid raw material is an element simple substance except carbon, a single semiconductor, an organic semiconductor, a polymer semiconductor or the like, it is preferable to heat and melt the solid raw material to obtain a melt. Specifically, a solid raw material is put into a copper crucible whose inside is water-cooled, and the solid raw material except carbon is heated and melted by irradiating with an electron beam to obtain a melt. If necessary, put a container called hearth liner in a copper crucible,
A solid raw material excluding carbon, such as a single element or a compound, is heated and melted therein. Instead of the copper crucible, a crucible made of alumina, magnesia, aluminum nitride, graphite, boron nitride composite or the like can be used. Since alumina, magnesia, and aluminum nitride are insulators, it is necessary to impart conductivity. In addition, when these are used, it is expected that the melt does not serve as an electrode, and a metal portion such as copper around the melt serves as an electrode to discharge.

The melting method may be electron beam heating, resistance heating, arc discharge, or the like, and any method may be used. The entire solid raw material may be completely melted or only the surface thereof may be melted, but in the case of electron beam heating, the electron beam current is increased so that the vapor is sufficient so that the following discharge occurs. The melt is used as a cathode, and an electric discharge is generated between the melt and the anode arranged above the melt. Here, the anode is connected to a discharge DC power supply. An AC power supply may be used instead of the discharging DC power supply. This discharge causes the vapor of the melt to be ionized to generate plasma.

The solid raw material in the present invention is not particularly limited as long as it can be vacuum-deposited, and includes, for example, element simple substance, its alloy or compound. As a simple element, titanium, silicon, boron, carbon, magnesium, aluminum, vanadium, chromium, iron, cobalt, nickel,
Copper, zinc, gallium, germanium, niobium, molybdenum, palladium, silver, indium, tin, tantalum, tungsten, rhenium, iridium, platinum, gold, mercury,
It contains lead, bismuth, thallium, germanium, alloys such as nickel-chromium, iron-chromium, iron-nickel-chromium, platinum-iridium, and compound semiconductors such as GaAs and CdS, and polyacene compounds. It includes polycyclic aromatic compounds, organic semiconductors such as merocyanine, and polymer semiconductors having conjugated double bonds such as polyacetylene. When an alloy or a compound is used as a raw material, it is expected that any element in the alloy or the compound will be selectively evaporated or decomposed, resulting in poor controllability. If you want to thin film formation or injection of alloys or compounds,
It is more practical to use a plurality of evaporation sources at the same time as in ordinary vacuum evaporation.

Carbon can be used because it sublimes without forming a melt, but vapor is generated.

The melt in the present invention is a melt of the above-mentioned solid raw material, and needs a melt temperature sufficient to supply sufficient vapor to cause discharge between the cathode body and the anode. The amount and fluidity of the melt do not matter. For elements such as carbon that sublime without forming a melt, vapor can be ionized to perform ion implantation and / or film formation.

The cathode body comprises a melt and a crucible having an arbitrary shape for holding the melt.

The size of the object to be treated in the present invention is that which can be accommodated in the vacuum chamber, and there is no limitation as long as the size of the vacuum chamber is increased. The shape of the object to be processed is arbitrary, such as a plate shape or a three-dimensional shape. The plate shape is easier to process in terms of uniformity, but
One of the features of the present invention is that ions can be implanted into a three-dimensional object.
Is one. The material of the object to be processed is a conductive material such as metal or semiconductor. When the object to be processed is insulative, for example, when the object to be processed is a plate, the back surface of the plate is in contact with a metal, and when the object to be processed is three-dimensional, insert a conductor inside the three-dimensional object. , They need to be connected to a high voltage pulse power supply.

The condition of the surface of the object to be treated is cleaned by performing cleaning such as ordinary vacuum deposition.

In a preferred embodiment of the present invention, a high voltage pulse power source is used to apply a negative high voltage pulse (0 to -100 k) to an object to be processed placed in the generated plasma.
V) is applied to inject and / or form positive ions in the plasma on the surface of the object to be processed. At this time, the electron beam has an acceleration voltage of 0.1 kV to 20 kV and a current of 10 mA to 1000
mA, discharge current is 0 to 1000 A, pulse width of high voltage pulse is
0 μs to 300 μs, high voltage pulse repetition frequency 0 to 500
kHz. Each condition is a realistic reference value,
It is not limited to that.

The amount of ion implantation is controlled by the electron beam current, the discharge current, the pulse width of the high voltage pulse and the number of pulses, and the amount of ion implantation increases with the increase. The same applies to the amount of film formation when there is a shielding plate for vapor deposition particles. In the absence of the shielding plate, film formation by ions and film formation by vapor (neutral atoms) occur simultaneously, so the film formation amount also depends on the film formation amount by vapor.

Generally, when ion irradiation of a solid element is performed, ion implantation is mainly performed when the negative bias is about −2 to −100 kV, and ion implantation and film formation are performed at about −2 to 0 kV. However, since the transition from ion implantation to film formation is continuous, the boundary of negative bias is not clear, and changes depending on the element.

When the ion implantation is continued, the composition of the implanted elements approaches 100% on the surface, and the film is formed. In this case, sputtering occurs at the same time as the implantation, and a part of the formed film is scraped off, resulting in poor efficiency. Therefore, when performing only film formation, reduce the magnitude of the negative bias,
In some cases, set to 0 V.

If necessary, nitrogen gas and / or oxygen gas and / or hydrocarbon gas or the like is introduced into the apparatus of FIG. 1 from the gas introduction pipe to form a compound thin film such as a nitride or oxide film. You can also

With the structure shown in FIG. 1, ion implantation and simple vacuum deposition occur simultaneously. However, if only ion implantation is desired, a shield plate of an appropriate size is inserted between the object to be processed and the anode. The neutral vapor deposition elements that go straight ahead are prevented from reaching the object to be processed, and only the ions in the plasma are attracted to the object to be processed (FIG. 2).

[0023]

EXAMPLES Examples will be shown below to further clarify the features of the present invention.

Example 1 In the apparatus shown in FIG. 1, after evacuation, 10 kV, 130 mA
Titanium as a solid raw material was melted by the electron beam.
Applying 100 V to the anode using a DC power source for discharge, plasma is generated by discharge, and then the arc current is about 10 A.
Kept to be. In this state, pulse voltage -1 is applied to the stainless steel plate (SUS304 plate, 100 × 100 × 0.5 mm thickness) of the object to be treated.
By applying a pulsed bias with a pulse width of 0 kV and a pulse width of 10 μs using a high-voltage pulse power source, ions in the plasma were attracted to the surface of the object to be implanted. Using the high-voltage probe, current monitor, and oscilloscope of Figure 1, -1
Fig. 2 shows the results of waveform measurement of the applied voltage when 0 kV was applied and the injection current that flowed into the workpiece (including the holding component).
Shown in.

No droplets were observed on the treated surface by observation with an optical microscope.

[0026]

According to the present invention, when a raw material used for arc discharge is melted and this melt is used as a cathode to cause discharge,
It becomes possible to perform plasma ion implantation in which elements other than the target element and droplets are not mixed at all.

In the present invention, plasma can be generated from silicon or boron, which is unlikely to cause vacuum arc discharge, as a raw material, so that plasma ion implantation of most solid elements including silicon and boron is possible.

According to the film forming method of the present invention, a uniform film can be formed on the treated surface by an optical microscope without any droplets of micron or more being observed.

The ion implantation according to the present invention is performed by adding impurities for controlling the conductivity type (pn) of a semiconductor, forming a compound with a base material, and pretreating film formation to form a gradient composition layer for improving adhesion and impact resistance. To form between the substrate and the coating.

The film formation according to the present invention is carried out for the production of semiconductor elements, optical elements, mechanical parts, tools and the like in order to impart wear resistance, corrosion resistance and decorativeness.

On the surface of a conventional solid cathode, coarse particles (droplets) having a size of several microns are generated due to vacuum arc discharge,
It scattered into the vacuum and partly adhered to the object to be treated, impairing the smoothness of the surface. On the other hand, in the present invention in which the melt is used as the cathode, since the liquid droplets are not generated, the above problems do not occur.

[Brief description of drawings]

FIG. 1 shows a plasma ion implantation apparatus using discharge using a melt as a cathode.

FIG. 2 shows a plasma ion implantation apparatus using discharge with a melt as a cathode.

FIG. 3 shows a relationship between an implanted ion current flowing through an object to be processed and an applied voltage in Example 1.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nobuteru Tsubouchi             1-8-31 Midorigaoka, Ikeda-shi, Osaka Independent Administrative Law             Kansai Center, National Institute of Advanced Industrial Science and Technology (72) Inventor Yuji Horino             1-8-31 Midorigaoka, Ikeda-shi, Osaka Independent Administrative Law             Kansai Center, National Institute of Advanced Industrial Science and Technology F-term (reference) 4K029 BA17 BA41 CA03 CA04 CA09                       CA10 CA13 DA10 DE02

Claims (11)

[Claims] 1. A method of applying a negative high voltage pulse to an object to be processed in plasma to perform ion implantation and / or film formation on the object to be processed, which is a solid raw material as a material evaporation source used for plasma generation. A method comprising using the melt or sublimate of the above. 2. The method according to claim 1, wherein the solid raw material is a simple substance of an element, an alloy thereof, or a compound capable of being vacuum-deposited. 3. The method according to claim 2, wherein the compound capable of being vacuum-deposited is an elemental semiconductor, an organic semiconductor or a polymer semiconductor. 4. The method according to claim 1, wherein the material evaporation source used for plasma generation is a melt of a solid raw material. 5. The method according to claim 1, wherein the solid raw material is carbon. 6. The method according to claim 1, wherein the plasma is generated in the presence of nitrogen gas and / or oxygen gas and / or hydrocarbon gas. 7. The method according to claim 1, wherein a shield plate is present between the object to be processed and the melt or sublimate to perform ion implantation or film formation. 8. A device for applying a high voltage pulse to an object to be processed having a high voltage pulse power source and a support device for the object to be processed; an electric discharge comprising an anode, a cathode body capable of holding a solid raw material melt or carbon, and a discharge power source. Device: Device for melting or sublimating solid raw material or carbon on cathode body; Ion implantation and / or film forming device equipped with a vacuum chamber. 9. The apparatus according to claim 8, further comprising an inlet pipe for nitrogen gas and / or oxygen gas and / or hydrocarbon gas. 10. The apparatus according to claim 8, wherein a shield plate is provided between the object to be processed and the material generation source. 11. A plasma-ion-implantation / film-formation treatment product in which there are no droplets on the surface to be treated and the ion-implantation material is only a material evaporation source.