JPH05243172A - Ion implantation device used for manufacturing semiconductor device - Google Patents

Abstract

PURPOSE:To prevent such troubles that ions are partially changed in energy or charge due to collision with neutral molecules by a method wherein a second mass spectrometer, which carries out the mass spectrometry of ion by deflecting an ion beam before it is implanted into a semiconductor wafer, again, after the mass spectrometry of the ion is carried out once. CONSTITUTION:Passing through a mass spectrometer 3, ions 13 of required energy and charge are made to collide with neutral molecules 17 and changed in energy and charge, and an ion beam which contains ions 16 out of a required value in energy and charge is deflected again by a magnetic field in a second spectrometer 8, and only ions 12 prescribed in charge and energy are made to pass through the second spectrometer 8 and implanted into a semiconductor wafer in an implanting section 7. By this system, a distance between the second spectrometer 8 and the implanting section 7 can be shortened, ions are lessened in range, and an ion beam passing through the second spectrometer 8 is restrained from colliding with neutral molecules, so that ions out of a prescribed value in charge and energy are prevented from being implanted into a semiconductor wafer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implantation apparatus for manufacturing semiconductor devices, and more particularly to a method for selecting ions.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional ion implanter for manufacturing a semiconductor device (hereinafter referred to as an ion implanter) has an ion generator 1 for generating ions and an ion beam for applying energy to the generated ions. A pre-acceleration unit 2 for generation, a mass analysis unit 3 for passing only ion species having a specific energy and mass, a chamber 1 for connecting a pump, a gauge, and the like.
1. An implanting section 7 for implanting ions into a semiconductor wafer.

Next, the path of ions will be described. First, the molecules are ionized in the ion generator 1 to generate positive ions of each energy. Next, the cations generated by setting the potential of the pre-stage acceleration unit 2 to a low potential with respect to the ion generation unit 1 move from the ion generation unit 1 to the pre-stage acceleration unit 2 with the energy of the potential difference, and pass through the pre-stage acceleration unit 2. , Reaches the mass spectrometric section 3. Here, the ions are deflected by the magnetic field, and the charged ions 14 of undesired energy and mass cannot pass therethrough,
Only ions 12, 13, 16 of specific energy and mass are allowed to pass. The ions that have passed through the mass spectrometric section 3 pass through the chamber 11 and reach the implantation section 7, where they are implanted into the semiconductor wafer.

[0004]

In the conventional ion implanter, the ion beam is deflected by the magnetic field in order to pass the ions of the desired energy and charge.
After being deflected, the energy charge of some of the ions 13 and 16 is changed by collision with the neutral molecule 14 and the ions are directly injected into the semiconductor wafer.

[0005]

In the ion implantation apparatus of the present invention, after performing mass analysis once by deflecting the generated ion beam, the ion beam is deflected again before implantation into a semiconductor wafer to perform mass analysis. It is equipped with a mass spectrometer.

[0006]

The present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a mechanical scanning ion implantation apparatus according to a first embodiment of the present invention. Target energy,
The ion beam containing the charged ions 16 collides with the neutral molecules 17 after passing through the mass spectrometric section 3 to change the energy and electric charge, resulting in an undesired energy and the charged ions 16 due to the magnetic field in the second mass spectrometric section 8. It is deflected again, and only the ions 12 having the desired energy and electric charge pass therethrough, and are injected into the semiconductor wafer by the injection unit 7. In this method, the distance between the second mass analysis unit 8 and the injection unit 7 can be shortened, the range distance of ions between them can be shortened, and the collision between the ion beam and the neutral molecule after passing through the second mass analysis unit 8 can be achieved. There is an effect that can suppress.

FIG. 2 is a block diagram of an electrostatic scanning type ion implantation apparatus according to a second embodiment of the present invention. Ions having the target energy and electric charge collide with the neutral molecules 17 after passing through the mass spectrometric unit 3 to change the energy and electric charge, and the ion beam including the undesired energy and electric charge 16 is deflected by the deflecting unit 9. In this case, the ions are deflected by the electric field, and by passing through the slit 10, only the ions 12 having the desired energy and electric charge pass therethrough, and the ions are injected into the wafer by the injection part 7. In this method, since the deflection is performed by the electric field, it is possible to remove the ion 15 having the target energy and the ion having the same charge as the ion having the charge, and the energy other than the target which is deflected. is there.

[0008]

As described above, according to the present invention, the mass analysis is performed once after the generated ion beam is deflected and then before the implantation into the wafer again, the mass analysis is performed. There is an effect that it is possible to prevent the injection of ions of external energy and charges into the wafer.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of the present invention.

FIG. 3 is a configuration diagram showing a conventional technique.

[Explanation of symbols]

1 Ion generation part 2 Pre-acceleration part 3 Mass analysis part 4 Post-acceleration part 5 Convergence part 6 Scanning part 7 Injection part 8 Second mass analysis part 9 Deflection part 10 Slit 11 Chamber 12 Target energy and charge ion 13 Mass analysis part Energy of collision with neutral molecule after passing through, ion of charge 14 undesired energy that cannot pass through mass spectrometric section, ion of charge 15 undesired energy after passing through mass spectrometric section, ion of charge 16 objective after collision Ions that became external energy and charge 17 Neutral molecule

Claims (1)

[Claims] 1. A semiconductor device manufacturing apparatus, comprising: a second mass spectrometric section for performing mass spectrometric analysis by deflection after once performing mass spectrometric analysis by deflection of a generated ion beam before implanting a semiconductor wafer again. Ion implanter.