JPS6310451A - Electron shower device for ion implanting apparatus - Google Patents

Abstract

PURPOSE:To prevent negative electrification by electron and static electricity break down by using a circular paraboloid reflector, which reflects electrons proceeding for target to the opposite direction, as an electron reflector. CONSTITUTION:Thermal electrons are generated by flowing electric current through a metal filament 1b from a power supply 2. These thermal electrons are accelerated toward a circular paraboloid reflector 4b by several hundred volts applied by a bias power supply 3. On collision of these electrons to the reflector 4b, secondary electrons whose energy is ranging from several eV to several is of eV are generated. The circular paraboloid reflector 4b pushes these secondary electrons effectively into an ion beam 6 and the electrons neutralize charges of the ion beam itself. Furthermore, since the reflector reflects the electrons proceeding for target 7 to the opposite direction, electrons 5 with energy do not directly collide with a target 7. Accordingly, positive electrification by the ion beam 6, negative electrification by the electron shower, further static electricity break down on the target 7 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic shower device for preventing charge accumulation or electrostatic damage in an ion implantation device.

[Conventional technology]

FIG. 2 shows a schematic diagram of the configuration of a conventional electronic shower device for an ion implanter. In the figure, 1a is a metal filament (for example, tungsten), 2 is a filament power supply connected to the filament 1a, 3 is a bias power supply for accelerating electrons, 4a is an electron reflection plate, and 5 is a reflection plate 4a that is emitted from the filament 1a. 6 is an ion beam, and 7 is a target (for example, a silicon wafer).

Next, the operation will be explained. By passing current through the metal filament 1a from the filament power supply 2, thermoelectrons are generated. These hot electrons are accelerated by the bias power supply 3 at several hundred volts toward the electron reflection plate 4a. When the accelerated electrons collide with the electron reflection plate 4a, secondary electrons 5 of several to ten-odd electron volts are generated.

At this time, the electron reflecting plate 4a faces the target 7, and the generated secondary electrons 5 are directed toward the target. This neutralizes the charge on the target that is positively charged when the ion beam 6 hits it.

[Problem that the invention seeks to solve]

Conventional electronic shower equipment is configured as described above, so energetic electrons directly hit the target surface, causing the target to be truly charged by the electrons, and this charging also causes electrostatic damage to the target. There was a problem.

This invention was made to solve the above-mentioned problems, and aims to provide an electronic shower device that can prevent negative charging due to electrons and electrostatic damage.

[Means for solving problems]

In the electron shower value aperture according to the present invention, the electron reflection plate is a circular parabolic reflection plate, and the electrons are reflected in the opposite direction to the direction toward the target.

[Effect]

In this invention, the circular parabolic reflector effectively pushes electrons into the positively charged ion beam, neutralizes the charge of the ion beam itself, and directs the electrons toward the target. By reflecting the electrons in the opposite direction, it prevents the energetic electrons from directly hitting the target.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 1b is a metal filament (e.g. tungsten), 2 is a filament power supply connected to filament 1b, 3 is a bias power supply for accelerating the thermoelectrons emitted from filament 1b, and 4b is the opposite direction to the target. 5 is a circular reflecting plate that reflects electrons in the direction; 5 is an electron emitted from the filament 1b and reflected by the reflecting plate 4b; 6 is an ion beam; and 7 is a target (for example, a silicon wafer).

Next, the operation will be explained. By passing a current through the metal filament 1b from the filament current 'tA2, hot electrons are generated. Thermionic electrons generated from the filament 1b are accelerated by a bias power source 3 at several hundred ports toward a circular parabolic reflector 4b. These electrons are reflected on the reflecting plate 4b.
When it collides with , secondary electrons 5 of several to ten-odd electron volts are generated. The circular parabolic reflector 4b effectively pushes the secondary electrons 5 into the ion beam 6, neutralizes the monotonous charge of the ion beam 6, and directs the secondary electrons 5 in the opposite direction to the target 7. Since the electrons are reflected, the energetic electrons 5 do not directly hit the target 7. This makes it possible to prevent the target 7 from being positively charged by the ion beam 6 and negatively charged by the electron shower, as well as from electrostatic damage.

〔Effect of the invention〕

As described above, according to the present invention, in the electron shower device for an ion implanter, the electron reflector is a circular parabolic reflector that reflects electrons in the opposite direction to the direction toward the target. The electrons with the ion beam do not directly hit the target and are effectively pushed into the ion beam, preventing the target from being negatively charged and electrostatically damaged by the electrons, and also prevents the target from being negatively charged and electrostatically charged by the ion beam. It has the effect of preventing electrical damage.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an electronic shower device according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing a conventional electronic shirt device. 4b is a circular parabolic electron reflector, 5 is an electron beam, 6 is an ion beam, and 7 is a target. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) In an electronic shower device for an ion implanter that neutralizes positive charges generated during ion implantation by an ion implanter, a circular shape that reflects electrons into the ion beam in the opposite direction to the direction toward the target is used. An electronic shower device for an ion implanter, characterized by comprising a parabolic electron reflector.