JPH04147972A - Method for surface reformation - Google Patents

Abstract

PURPOSE:To enable surface reformation for a large area with high efficiency and enough uniformity by irradiating a plate to be treated with plural beams superposed and specifying the electric current density in each superposed area. CONSTITUTION:Plural numbers of ion beam generators are parallely provided for a vacuum chamber 14 in which a substrate 18 to be treated is disposed. The electric current densities of ion beams 15, 16, 17 are controlled to show Gaussian curves 19, 20, 21, respectively, or a superposed curve of these curves. The current density 22 in the superposed part of each current density distribution is specified to 85-115% of the center current density 23 of each beam. Thereby, the substrate 18 having a large surface area can be treated by continuously changing the relative position of the substrate 18 and ion beams 15, 16, 17.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a surface modification method for improving various properties of a material using an ion implantation method in which the surface of a material is irradiated with an ion beam or an ion mixing method. .

[Conventional technology]

Surface modification methods of materials using ion beams, such as ion implantation and ion mixing, which is a process that combines ion implantation and film formation, are chemical, mechanical, magnetic, and! It is a useful technology for improving properties such as gas, and in particular, processing using metals and semimetallic elements such as carbon and boron as ion beam elements has advantages different from processing using gaseous element ions. The effect of modifying the substrate to be processed can be obtained.

By enabling ion implantation and ion mixing of metal and metalloid elements using ion beams, large-area processing is possible for processing mechanical parts, device parts, and sheet-like materials with the size of general-purpose products all at once. Its field of application is even wider.

FIG. 2 is a schematic diagram of a conventional apparatus for surface modification using an ion beam. An outline of the technique will be explained with reference to FIG.

Since the ion beam generated by the ion source 7 for a conventional device contains a large number of unintended ions in addition to the target metal or metalloid element, the elements were sorted out by the mass separation magnet 5. After that, ion beam 1 is obtained. In order to irradiate a large area with the ion beam 1 of metal and metalloid elements,
In the conventional apparatus shown in FIG. 2, two-dimensional scanning is performed on the surface of the substrate 3 by passing the beam through a space 2 to which an amplitude electric field is applied by an amplitude electric field applying device 6. It is used. Note that 4 is an accelerating tube.

[Invention or problem to be solved]

In this case, there is a technical upper limit to the amount of current per ion beam, and the maximum is about 100 mA. The current value that can actually be stably handled is one order of magnitude smaller than this value. Therefore, when the substrate to be processed has a large area, as the width of the scan by the amplitude electric field is expanded, the current density per unit area decreases and the processing time increases.
As a result, processing efficiency decreases.

Therefore, it may be possible to improve the processing efficiency by using two or more ion beams in parallel, but the conventional device uses an accelerator tube 4, a mass separation magnet 5, and an amplitude electric field as shown in Fig. 2. Equipment such as the device 6 is huge and complicated, and therefore occupies a large space, making it extremely difficult to realize it as a practical equipment.

Attempts to increase the area of the beam itself include a packet-type ion source generally used for heating a nuclear fusion reactor, a Kaufmann-type ion source used in an ion engine, and a device with a devised grid shape (Japanese Patent Application Laid-Open No. 132-699-1982). issue),
Method using sheet plasma (4! 1986-4738
No. 1), etc., but all of them are related to the generation of a beam of only gas ion species.

On the other hand, an ion beam generator is known in which cathode material is evaporated and ionized by arc discharge in a vacuum, accelerated by a grid electrode to which a high voltage is applied, and extracted as an ion beam.

Fig. 3 shows an example of the device by Brown, I.G.
:TheMetal Vapor Vacuum Ar
c(MEVVA) High CurrentIon
5source, IEEE Trans, on Nuc
l,, N5-32. (1985) and JP-A-63-27
This is a device described in Publication No. 6858, and MEVV
A-type ion beam generator.

The operating principle of the MEVVA type ion beam generator will be explained below.

When arc discharge occurs between the cathode 8 and anode 9 in a vacuum, the cathode material is evaporated and ionized. By applying a high voltage to the grid electrode IO, ions are accelerated and extracted as a beam. If this device is used as an ion source for ion implantation, it is possible to generate ion beams of metal and metalloid elements more easily than with conventional ion implantation devices.

However, the ion beam C beam current density generated from the ion source has a Gaussian distribution or a distribution in which Gaussian distributions are superimposed on the substrate to be processed, so even if the beam diameter is simply increased, uniform processing cannot be achieved. In order to do this, most of the tail of the beam distribution must be cut off, which may reduce processing efficiency.

The present invention solves the above problems and provides a surface modification method in which the surface of a material to be treated is efficiently treated over a large area with practically sufficient uniformity by irradiation with a metal or metalloid ion beam.

[Means to solve the problem]

The gist of the present invention is that when performing surface treatment on a material to be treated with an ion beam of one or more elements selected from metals and semimetals such as carbon and boron, an arc discharge is caused in a vacuum to cause a cathode material Using multiple ion beam generators, the ions are evaporated and ionized, accelerated by a grid electrode to which a high voltage is applied, and extracted as ion beams. This is a surface treatment method characterized by processing in parallel by configuring the beam current density to be 85% to 115% of the beam current density at the center of each beam. This surface treatment method is characterized in that the treatment is performed continuously by changing the relative position of the ion beam irradiation spot and the substrate to be treated.

[For production]

FIG. 1 shows an example of the implementation of the present invention, and the MEV shown in FIG.
FIG. 3 is a schematic cross-sectional view showing a state in which three VA ion beam generators are installed in parallel.

ME that evaporates and ionizes the cathode by arc discharge in a vacuum and extracts an ion beam from a high voltage grid electrode.
VVA ion beam generator A11. When generating an ion beam of one or more elements among metals, carbon, and boron using [Otsu 12, C] 3, the ion beam contains discharge buffer gas, unintended elements such as halogen elements, etc. Since the ion beam generator does not include ion beam generators, it is possible to generate a highly pure beam in a small acceleration space without a mass separator and an amplitude electric field generator, so two or more ion beam generators can be arranged in parallel.

The current density distribution of each of the ion beams 15, 16, and 17 irradiating the substrate to be processed 18 placed in the vacuum chamber 14 shown in FIG. 1 is Gaussian, as shown as +9, 20, and 21 in FIG. It takes the form of distribution, Gaussian distribution, or multiple superposition. By adopting a configuration such that the current value 22 at the overlapping part of the tails of the current density distribution of each beam shown in FIG. 4 is 85% to 115% of the current density value 23 at the center of each beam, Uniform treatment can be achieved over a large area.

The reason why the range is set from 85% to 115% is that if the distribution is within this range, the variation in characteristics obtained through processing is sufficiently small for practical purposes.

In FIGS. 1 and 4, three ion beams are shown as an example, but there is no problem with the number of ion beams, even two. Otsu 12. Each of the ion beams 13 may be one ion source, or may be a set of each or a plurality of ion beam generators. Further, the ion beam generator may be arranged in a two-dimensional manner instead of in a straight line.

In addition, the substrate to be processed 18 and the ion beam A 15. By continuously changing the relative positions of the parts 16 and 17, it is possible to process the surface of a substrate having a wider area. Here, the movement of changing the relative position is not #11 even if it is a step-like movement in which movement and stopping are repeated.

〔Example〕

Two MEVVA ion beam generators A and B, the setting conditions of which are shown in Table 1, are installed in parallel, and the substrate to be processed is ion-implanted using ion beam A and ion beam B generated by each ion beam generator. Ta.

At this time, while the beam current density at the center of ion beams A and B is 70 μA, the beam current density at the midpoint where the skirts of ion beams A and B overlap is 60 μA.
It satisfies the conditions of 115% to 85%.

Table 2 shows that the substrate to be processed is fixed in the chamber, and the implantation dose at the center of each beam is 3×+017Ti/c.
The results are shown in which the maximum concentration of titanium injected into the substrate to be processed was measured at each point by glow discharge spectroscopy, where m' is the maximum concentration of titanium injected into the substrate to be processed. Since the effective implantation dose added into the substrate to be processed is saturated due to the sputtering effect during implantation, there is almost no difference in the doped titanium concentration finally obtained in the substrate to be processed between the center part of the beam and the bottom part of the beam. I got a result that does not occur.

Table 2 Table 2: Concentration of implanted elements in the ion mud and on the substrate to be treated [Effects of the invention] As described above, according to the method of the present invention, the surface treatment of metals and semimetals with an ion beam can be This can be done efficiently and uniformly over a wide area, which was difficult to do with conventional methods.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a device that uses vacuum arc discharge as the principle of ion generation and irradiates a substrate to be processed by installing ion beam generators in parallel. A schematic diagram of the configuration for irradiating ion beams. Figure 3 is a diagram of the principle configuration of the MEVVA type ion source as an example of an ion source that uses vacuum arc discharge as the principle of ion generation. Figure 4 shows the ion beam generated from multiple ion beam generators. 2 is a drawing showing the distribution of beam current density of an ion beam on a substrate to be processed. 1... Ion beam generated by a conventional device, 2...
A space to which an amplitude electric field is applied, 3... substrate to be processed,
4... Accelerator tube, 5... Mass separation magnet, 6... Amplitude electric field adding device, 7... Ion source used in conventional ion beam generator, 8... MEVVA type ion beam generation Apparatus D, 9... MEVVA type ion bioion beam generator D, lO... MEVVA type ion bioion beam generator D, 11... MEVVA type ion beam generator A, 12... MEVVA type ion beam generation Equipment Otsu, 13... MEVVA ffi ion beam generator C, 14... Vacuum chamber for processing, 15... Ion beam A, 16... Ion beam Otsu, 17... - Ion beam C, 18. ...Substrate to be processed, 19...In the ion beam current distribution, 20...Ion beam current distribution B, 21...Ion beam current distribution, 22...In the overlapping part of the bottom of the ion beam Current value, 23... Current value agent at the center of the ion beam
Patent Attorney Masamitsu Akizawa and 1 talent 1 illustration 2 illustrations

Claims (1)

[Claims] (1) When surface-treating a material with an ion beam of one or more elements among metals and metalloids such as carbon and boron, an arc discharge is generated in a vacuum to evaporate the cathode material. Using multiple ion beam generators, the ions are ionized, accelerated by a grid electrode to which a high voltage is applied, and extracted as an ion beam.The beam current of the portion of the substrate to be processed is irradiated with multiple beams in a superimposed manner. A surface modification method characterized in that the density is configured to be 85% to 115% of the beam current density at the center of each beam and the processing is performed in parallel. (2) The surface modification method according to claim (1), wherein the treatment is performed continuously by changing the relative positions of the two or more ion beam irradiation spots and the substrate to be treated.