JP2013229106A - Ion beam irradiator for polymer material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ion beam irradiator for a polymer material which allows for measurement of an ion beam irradiation current without being affected by release of a large amount of gas during ion beam irradiation, and accurate measurement of irradiation amount.SOLUTION: A target vacuum chamber has an ion beam inlet, and is provided internally with a Faraday cup, irradiation sample installation means, and a partition wall for blocking gas release. The Faraday cup is disposed between the ion beam inlet and the irradiation sample installation means, and the partition wall for blocking gas release is disposed between the Faraday cup and the irradiation sample installation means. Consequently, the Faraday cup installation part and an irradiation sample are separated by the partition wall for blocking gas release, and the gas released from the irradiation sample by ion beam irradiation is prevented from arriving at the Faraday cup.

Description

  The present invention relates to an apparatus for irradiating a polymer material with an ion beam.

  Up to now, ion implantation into silicon or ion implantation into metal surfaces has been performed for improving friction and wear characteristics for semiconductor manufacturing. As such an ion implantation method and apparatus therefor, an ion implantation method and apparatus for implanting ions into a semiconductor substrate while controlling the pressure in the ion beam path from the ion mass spectrometer to the implantation chamber are known. Yes. For example, Patent Document 1 describes an ion implantation method and apparatus that suppresses pressure fluctuations during ion implantation in the ion beam path after the ion mass spectrometer and improves the accuracy of the ion dose.

  Ion implantation into silicon wafers for semiconductor manufacturing and metal implantation to improve friction and wear causes slight outgassing from contaminated layers attached to the surface during ion beam irradiation. The release of gas from the inside of the material was mild, so that the gas was not released so as to hinder the measurement of the ion beam current, and the measurement of the ion beam current was hardly affected.

In recent years, ion implantation into polymer materials has begun to improve the functionality of medical materials. For example, Patent Document 2 discloses a cell adhesion control material characterized in that cell adhesion is expressed by irradiating a polymer material with an ion beam, and an irradiation site is a cell adhesion surface, and A method for producing a cell adhesion control material characterized by irradiating a polymer material with an ion beam at an acceleration energy of 50 to 150 keV and an irradiation amount of 1 × 10 ¹⁵ pieces / cm ² or more is described. Further, Patent Document 3 discloses that the biopolymer material coated on the base material is irradiated with an ion beam so that cell adhesion remains and platelet adhesion is suppressed. A thrombus material and a biopolymer material coated on a substrate are irradiated with an ion beam at an acceleration energy of 50 to 150 keV and an irradiation amount of 1 × 10 ¹⁴ to 1 × 10 ¹⁷ pieces / cm ^2. A method for producing an antithrombotic material is described.

JP-A-7-258846 Japanese Patent Laid-Open No. 5-49589 JP-A-9-299474

  In the case of ion implantation into the polymer material as described above, the irradiation area is often several centimeters square in the trial production at the research level, and although gas emission occurs, it does not affect the measurement of the ion beam irradiation current. . However, in the case of a polymer material that is easily decomposed by ion beam irradiation, the ion irradiation area is large in ion implantation into a large-area polymer material for mass production. There is a problem in that the amount of emission increases and the ion beam becomes neutral, making it difficult to measure the beam current. That is, as the irradiation area increases, the amount of released gas increases, and there is a problem that irradiation current measurement is impossible due to collision with the gas or neutralization in large-area ion implantation.

  As described above, in an ion implantation apparatus capable of processing a large area, when the irradiation target sample is a polymer material, a large amount of gas is released from the polymer material during irradiation. This gas makes it difficult to measure current with an irradiation current measuring element called a Faraday cup. The present invention provides an ion beam irradiation apparatus for a polymer material that can measure an ion beam irradiation current without being affected by a large amount of gas emission during ion beam irradiation and can measure an accurate irradiation amount. Was a problem to be solved.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention are released during ion implantation by providing a partition wall that separates the Faraday cup installation part for irradiation current measurement and the irradiated target (polymer) part. The present inventors have found that it is possible to measure the irradiation current by blocking the gas emission, and the present invention has been completed.

  That is, according to the present invention, in the chamber having the ion beam inlet, the Faraday cup, the irradiation sample setting means, and the partition wall for the emission gas block are provided inside the chamber, and the ion beam inlet For the polymer material comprising a chamber in which the Faraday cup is provided between the irradiation sample setting means and a partition wall for a discharge gas block is provided between the Faraday cup and the irradiation sample setting means. An ion beam irradiation apparatus is provided.

Preferably, two or more Faraday cups are installed on a plane perpendicular to the traveling direction of the ion beam.
Preferably, four Faraday cups are installed on a plane perpendicular to the traveling direction of the ion beam, and the four Faraday cups are installed so as to exist at the vertices of a rectangle.

  Preferably, the emission gas blocking barrier is a cylindrical barrier having a Faraday cup side opening and an irradiation sample side opening, and the size of the Faraday cup side opening is constituted by the four Faraday cups. The irradiation sample side opening is smaller than the square plane and is larger than the Faraday cup side opening.

  The above-described ion beam irradiation apparatus for polymer material of the present invention can further include an ion source, an ion acceleration system, a mass separation system, and a scanner.

  Furthermore, according to the present invention, there is provided a method of irradiating a polymer material with an ion beam using the above-described ion beam irradiation apparatus for polymer material of the present invention.

  According to the ion beam irradiation apparatus for a polymer material according to the present invention, it is possible to measure the ion beam irradiation current without being affected by a large amount of gas emission at the time of ion beam irradiation, and an accurate irradiation amount can be measured. .

FIG. 1 shows a schematic view of an ion beam irradiation apparatus for a polymer material of the present invention. FIG. 2 shows a schematic diagram of an ion beam irradiation apparatus for a polymer material according to the present invention. FIG. 3 shows photographs before and after attaching the release gas block partition wall to the target chamber portion of the ion implanter. 3A is a photograph viewed from the A direction in FIG. 1, and FIG. 3B is a photograph viewed from the B direction. An aluminum sheet is used as the material of the partition wall, but any material that does not easily release gas by the collision of the ion beam may be used.

Hereinafter, the present invention will be described in more detail.
The present invention relates to an ion beam irradiation apparatus for a polymer material in which a Faraday cup and an irradiation sample setting means are provided inside a chamber having an ion beam inlet, and a Faraday cup setting portion for irradiation current measurement and an irradiation sample. By providing a partition for the emission gas block between the (polymer) part, the gas emission released from the irradiated sample at the time of ion implantation is blocked, and the irradiation current can be measured by the Faraday cup. . A Faraday cup is a metal (conductive) cup that captures charged particles in a vacuum.

Usually, the ion beam dose is given by the following equation.
Irradiation amount = (I × t) / (A × q × e)
I: Beam current t: Injection time A: Injection area q: Number of charges e: Charge (1.602 × 10 ⁻¹⁹ C)
As described above, the ion beam irradiation amount is obtained by integrating the beam current with time. However, when the ion beam is neutralized by the generated gas, the irradiation amount cannot be measured. In the present invention, neutralization of the ion beam by the generated gas is prevented by the partition wall for the released gas block.

  An outline of the apparatus of the present invention is shown in FIG. Four Faraday cups for current measurement are installed at the four corners (four corners of the square) on the front surface of the metal box with respect to the ion beam, and the ion beam that has passed through is irradiated onto the irradiated sample. The Faraday cup measures current by installing a partition wall for the emission gas block from the ion beam entrance to the back of the metal box so as not to block the ion beam that has passed through the metal box where the Faraday cup is installed. Make it possible.

  The number of Faraday cups is not particularly limited as long as it is one or more, but preferably two or more, particularly preferably four can be installed. When two or more Faraday cups are installed, preferably, two or more Faraday cups can be installed on a plane perpendicular to the traveling direction of the ion beam. In the embodiment shown in FIG. 1, four Faraday cups are installed on a plane perpendicular to the traveling direction of the ion beam, and the four Faraday cups are installed so as to exist at the apexes of a square. .

  The configuration of the barrier for the released gas block is not particularly limited. For example, it can be a cylindrical barrier having a Faraday cup side opening and an irradiated sample side opening. In the embodiment shown in FIG. 1, the size of the Faraday cup side opening is smaller than the square plane formed by the four Faraday cups, and the irradiated sample side opening is larger than the Faraday cup side opening. ing.

  By providing an ion source, ion acceleration system, mass separation system, and scanner further upstream of the polymer material ion beam irradiation apparatus shown in FIG. 1, the polymer material ion beam irradiation apparatus can be configured. . FIG. 2 shows a schematic diagram of an ion beam irradiation apparatus for a polymer material provided with an ion source, an ion acceleration system, a mass separation system, and a scanner.

  An ion beam irradiation apparatus for a polymer material shown in FIG. 2 includes an ion source that ionizes target ions, an ion acceleration system (ion acceleration tube), a mass separation system that separates only target ions, a scanner for scanning, And a sample chamber (a chamber having an ion beam inlet, in which a Faraday cup, an irradiation sample setting means, and a partition wall for an emission gas block are provided).

  The ion source includes an oven, a filament (cathode), an anode, and a coil, and gasifies an appropriate substance placed in the oven to generate an ion plasma of desired ions. The acceleration system is composed of an extraction electrode, a focus electrode, and the like, and the ion beam is given necessary energy while passing through it. The mass separation system includes a magnet that changes the direction of the ion beam by 90 °, and selects and removes impure ion species using the difference in the locus of ion species having different masses.

  The scanner is installed between the mass separation system and the sample chamber (chamber having an ion beam inlet), and a Y-scanner (deflection electrode) and an X-scanner can be installed. It is possible to perform uniform ion implantation on the irradiated sample placed in the sample chamber by electrically raster-scanning the ion beam.

  The features of the ion implantation method using this ion implantation apparatus are that it has a mass separation system, so that a single ion beam with very good purity can be obtained, and that the kinetic energy of ions is as high as 50 keV or higher. It is.

  According to the present invention, a polymer material can be irradiated with an ion beam using the above-described ion beam irradiation apparatus for polymer material.

  The irradiated sample is not particularly limited as long as it is a polymer material, but is preferably a biocompatible material. Preferable polymer materials include expanded polytetrafluoroethylene (ePTFE), biodegradable polymers (for example, polylactic acid or polyglactin), and particularly, expanded polytetrafluoroethylene (ePTFE) is preferable. . Moreover, what coated biopolymer materials, such as gelatin, collagen, fibronectin, laminin, or vitronectin, on base materials, such as a polystyrene, may be used.

Examples of ion species to be implanted include He ⁺ , C ⁺ , N ⁺ , Ne ⁺ , Na ⁺ , K ⁺ , N ₂ ⁺ , O ⁺ , O ₂ ⁺ , Ar ⁺ , Kr ^{+ and the} like. It is not limited.

The acceleration energy of the ion beam can be practically set in the range of several tens to several hundreds keV, preferably about 50 to 150 keV.
The irradiation amount (dose amount φ) is preferably in the range of 1 × 10 ¹³ to 1 × 10 ¹⁷ pieces / cm ² , or 5 × 10 ¹⁴ to 1 × 10 ¹⁷ pieces / cm ² .

  The following examples further illustrate the present invention, but the present invention is not limited to the examples.

Using the ion implantation apparatus shown in FIG. 1 to FIG. 3 (an apparatus in a state in which no release gas block partition is mounted and an apparatus in which the release gas block partition is mounted)
When an Ar ⁺ ion beam is irradiated to the polymer material (stretched polytetrafluoroethylene) with an acceleration energy of 150 keV without the release gas block partition, a large amount of gas is generated, and the ion beam current at the Faraday cup is generated. Measurement was impossible. On the other hand, as a result of attaching a partition wall and irradiating an ion beam under the same conditions, it became possible to measure the irradiation ion beam current with a Faraday cup.

Claims (6)

In a chamber having an ion beam injection port, a Faraday cup, an irradiation sample setting means, and a partition wall for an emission gas block are provided inside the chamber, and between the ion beam injection port and the irradiation sample setting means. The ion beam irradiation apparatus for a polymer material, comprising a chamber in which the Faraday cup is provided, and a partition wall for an emission gas block is provided between the Faraday cup and the irradiation sample setting means. The ion beam irradiation apparatus for polymer materials according to claim 1, wherein two or more Faraday cups are installed on a plane perpendicular to the traveling direction of the ion beam. The four Faraday cups are installed on a plane perpendicular to the traveling direction of the ion beam, and the four Faraday cups are installed so as to exist at the apexes of a quadrangle. The ion beam irradiation apparatus for polymeric materials as described. The barrier for the released gas block is a cylindrical barrier having an opening on the Faraday cup side and an opening on the irradiation sample side, and the size of the Faraday cup side opening is larger than the rectangular plane formed by the four Faraday cups. 4. The ion beam irradiation apparatus for polymer material according to claim 3, wherein the irradiation sample side opening is smaller than the Faraday cup side opening. Furthermore, the ion beam irradiation apparatus for polymeric materials in any one of Claim 1 to 4 which has an ion source, an ion acceleration system, a mass separation system, and a scanner. A method for irradiating a polymer material with an ion beam using the polymer material ion beam irradiation apparatus according to claim 1.