KR20010088093A - Electrode structure in plasma polymerization apparatus - Google Patents

Abstract

PURPOSE: A structure of electrodes in a plasma polymerization equipment is provided which uniformly coats a polymeric material on a sample by changing the structure of electrodes in the plasma polymerization equipment, thereby uniformly distributing an electric field on each parts of the sample. CONSTITUTION: In a plasma polymerization equipment, the structure of electrodes in a plasma polymerization equipment is characterized in that the shape of electrodes (11) impressing the discharging voltage to a sample (12) is formed in a bended structure such that both end parts of the electrodes (11) become further from the sample (12) by differing the center part and both end parts of the shape of electrodes.

Description

ELECTRODE STRUCTURE IN PLASMA POLYMERIZATION APPARATUS}

The present invention relates to an electrode structure of a plasma polymerization apparatus, and more particularly, to an electrode structure which prevents distortion of an electric field from occurring at an electrode end portion.

A method of modifying a sample surface by synthesizing a polymer, conventionally using ion implantation or ion beam irradiation using high energy (tens of keV to several MeV), or relatively low energy (0 to Samples of polymers may be prepared using ion beam sputtering deposition, ion beam sputtering deposition, or ion assisted deposition, using ion sources that produce particles of several keV. The method of vapor deposition on the surface was used.

However, since this method requires a relatively high energy and low vacuum state, the synthesis of the polymer is not easy and the cost required is high.

On the other hand, a surface treatment method using a plasma has been developed that can form a polymer on a sample substrate at low energy and low vacuum. In the above method, a vacuum is applied to the chamber, a reactive gas of monomers of the material to be synthesized is injected into the chamber, and then discharged at a direct current or high frequency using a power supply device. Plasma is generated, and predetermined ions are transferred to the sample substrate or the electrode to synthesize the predetermined polymer thereon. At this time, various chemical bonds are made according to the type and mixing ratio of the reaction gas, DC current, voltage, high frequency power or deposition time, and the polymer polymer having the required physical properties such as surface strength, adhesion and adsorption, hydrophilicity and hydrophobicity is sampled. By depositing on the surface, the sample surface can be modified without affecting the inherent properties of the sample substrate.

One embodiment of such a device is shown in FIG. 1, which comprises a chamber 1, a power supply 3, an electrode 4, a diffusion pump 5 and a rotary pump 6, inside a chamber. It consists of a thermocouple vacuum gauge 7 for measuring the degree of vacuum, an ion gauge 8 and injection holes 9 and 10 for injecting a reactive gas.

In order to deposit the polymer polymer on the sample 2 using the apparatus, the sample 2 is installed inside the chamber 1, and the rotary pump 6 and the diffusion pump 5 are started to increase the pressure inside the chamber. Maintain below 10 ^-3 Torr, checking with a thermocouple gauge (7) and ion gauge (8) attached to the chamber. The sample is positioned where it is biased by the power supply 3 to the anode (+) or the cathode (-), and the opposite electrode 4 is grounded. When the pressure of the chamber is maintained at a constant vacuum, a predetermined amount of reactive gas such as acetylene and nitrogen is injected into the chamber through the injection ports 9 and 10, and then the predetermined power to the substrate using the power supply 3 The reactive gas is discharged by applying. Then, the molecular bonds of the reaction gases in the plasma generated by direct current or high frequency are broken, and the broken chain and the activated cations or anions are bonded to form a polymer polymer on the surface of the sample substrate positioned between the electrodes. The anion is mainly used for the synthesis of the polymer polymer in the sample substrate having a, and the cation is mainly helpful in the sample substrate or the electrode having the low potential. At this time, although the substrate is mainly used aluminum (Al), insulators, ceramics or polymers other than metal may be used. In addition, the type of polymer deposited can be changed by changing the position of the sample substrate between the electrodes. Instead of placing the sample substrate between the two grounded electrodes, one of the electrodes is replaced with a sample substrate to supply power to the sample substrate. It is also possible to apply and ground the remaining electrodes.

In the case of forming a polymer polymer using such a conventional device, the polymer is produced by the reaction of radicals in the plasma of the reactive gas, and the polymer is bonded to the metal by the kinetic energy of electrons or cations, and the anode and the cathode Due to different potentials, average electron energies, and the like, polymerized films of different properties are formed depending on the position of the sample.

In the conventional plasma polymerization apparatus, the shape of the electrode is generally a sheet, and its cross section is straight. In FIG. 2A, the cross section of the shape is shown. In this case, the electric field is formed so that the electric field is perpendicular to the electrode 11 in the sample at the center of the sample 12. However, the electric field distortion occurs at both ends of the sample. In other words, since the electric field is concentrated by the edge effect at the end of the sample, the electric field becomes stronger, and thus the distribution of the electric field is different from that of the center of the sample. This distortion is shown in Figure 2b. The end of the sample 12 can be seen that the shape of the electric field is concentrated in comparison with the center portion in a curved form rather than a straight line. Differences in the electric field distribution at the center of the sample and the sample tip cause uneven plasma polymerization and degrade the quality of the sample to be polymerized.

Accordingly, an object of the present invention is to achieve a uniform coating of a polymer by changing the electrode structure of the plasma polymerization apparatus and equalizing the distribution of the electric field for each part of the sample.

1 is a schematic view showing a conventional plasma polymerization processing apparatus.

2A is a cross-sectional view showing a conventional electrode structure.

FIG. 2B is a schematic diagram showing the distribution of an electric field in the electrode structure of FIG. 2A.

3A is a cross-sectional view showing the electrode structure of the present invention.

FIG. 3B is a schematic diagram showing the distribution of electric fields in the electrode structure of FIG. 3A.

FIG. 3C is an enlarged cross-sectional view of part A of FIG. 3A.

4A to 4D are cross-sectional views showing various examples of the electrode structure of the present invention.

*** Explanation of symbols for main parts of drawing ***

1: Deposition chamber 2: Sample

3: power supply 4: counter electrode

5: rotary pump 6: diffusion pump

7: thermocouple vacuum system 8: ion gauge

9: gas regulator 10: gas regulator

11: electrode 12: sample

The present invention provides a plasma polymerization treatment apparatus, wherein a shape of an electrode for applying a discharge voltage to a sample is formed in a structure in which both ends of the electrode are bent away from the sample by different ends from the center portion. Provide the electrode structure of the device.

In the electrode structure, the distance between both ends of the sample and the electrode is d + √ d or more when the distance between the sample and the electrode is d.

The electrode structure of the present invention includes both the end of the electrode bent in the shape of an arch or bent in a straight form.

In addition, the end of the electrode may be formed by bending the electrode itself, or may be formed by attaching a separate electrode.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

3A shows an embodiment of the present invention. The distinguishing feature of the conventional electrode structure is that the edge of the electrode 11 is bent upwards. That is, by attaching a wing-shaped electrode at both ends of the electrode, the distribution of the electric field is not concentrated, so that it is more perpendicular between the electrode and the sample.

The distribution of the electric field by this electrode structure is shown in FIG. 3B. Unlike FIG. 2B, the distribution of the electric field is not concentrated at both ends of the sample, and the electric field also takes the form of a straight line rather than a curved shape.

Theoretically briefly look at the change in the intensity and distribution of the electric field by the electrode structure as follows.

First, the electric field can be expressed as

E = (Q / 4πε ₀ r ² A _r

Where Q is the charge amount, ε ₀ is the dielectric constant in vacuum, r is the distance from the electrode of charge Q , and A _r is the area. According to the above equation, the electric field is inversely proportional to the square of the distance. Therefore, if the linear distance between the electrode and the sample is r + √r, the component of the denominator is reduced by the ratio of r ² / (r ² + 2r√r + r) than when the distance is r. Therefore, if the linear distance between the electrode and the sample is r + √r, the electric field is reduced at this ratio. In general, if the distance between the electrode and the sample is about 10cm, the size of the electric field is reduced to about 1 / 1.75.

Through these results, the distance between the electrode and the sample is different from the center and both ends. In particular, by increasing the distance at both ends, the intensity of the electric field is relatively decreased, so that the intensity of the electric field can be uniform in the whole sample. .

In the electrode structure of this invention, it is preferable to design the shape of the electrode tip by the following method. Referring to FIG. 3C, which is an enlarged view of part A of FIG. 3A, the distance between the sample 12 and the electrode 11 is d and the electrode is bent upward as the sample ends. At this time, the curved height is indicated by √d. In this design, if the linear distance between the electrode and the sample is d + √d, the denominator component in the above equation is reduced at the ratio of d ² / (d ² + 2d√d + d) than when the distance is d, Considering the distance between the electrode and the sample, the intensity of the electric field is reduced by about 1/2. Since the electric field at the electrode end is about twice as large as the center of the sample, the strength of the electric field at the center and both ends of the sample can be made uniform by setting the bend height to √d or more.

The electrode structure of the present invention is characterized in that the end portion of the electrode is curved upward in an arcuate shape, but need not necessarily be curved. Various types of electrode structures to which the present invention can be applied are shown in FIGS. 4A to 4D. If the height of the tip of the electrode from the center of the electrode is √d or more, not only a curved form (FIG. 4A) but also a straight form (FIG. 4B) or a broken line form (FIG. 4C and 4D) may be used, and may be variously applied according to production conditions and purposes of use. can do.

According to the present invention, by varying the electrode structure of the plasma polymerization apparatus in the electrode end portion and the center portion, it is possible to uniformize the distribution of the electric field for each part of the sample, so that the polymer can be uniformly coated on the sample.

Claims (1)

In the plasma polymerization apparatus, the electrode for applying the discharge voltage to the sample is formed in a structure that is bent so that both ends of the electrode away from the sample by different ends from the center and both ends. rescue.