JPH01315938A - Ion implanting device - Google Patents

Abstract

PURPOSE:To improve the evenness in the ion implanting work extensively by providing a grand mask to regulate the passing position of ion beams and a static deflecting electrode to make the horizontal beam component and the vertical beam component into parallel beams respectively. CONSTITUTION:The ion beams whose passing position is regulated by the first grand mask 27 pass through a secondary electron suppressing electrode 28, and injected to the second static deflection system 31 which consists of a y direction deflecting plate 29 and an x direction plate 30. At the y direction deflecting plate 29, a voltage almost synchronous to a y direction scanning plate 22 and of a reverse bias is applied, and the incident ion beams 21 are repelled somewhat in the direction of the center between electrodes of the deflecting plate 29, and made into parallel beams to the y direction. The ion beams 21a are then injected to the deflecting plate 30 in the x direction. To the deflecting plate 30, a voltage synchronous to an x direction scanning plate 23 and of a reverse bias is applied, and made into parallel beams to the x direction in the same manner as the y direction deflecting plate 29. Consequently, an even implanting process of a semiconductive wafer can be carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention (Field of Industrial Application) The present invention relates to an ion implantation apparatus that enables parallel scanning irradiation with an ion beam.

(Prior Art) In general, ion implantation technology is widely used as a technology for doping an object to be processed, such as a silicon or gallium arsenide substrate, with impurities.

As an ion implanter used for such ion implantation,
For example, in a medium current type ion implanter, as shown in FIG. 3, an ion beam 4 output from an ion beam generator 3 consisting of an ion generator 1, a mass analysis magnet 2, etc. is accelerated by an accelerator 5, After being shaped into a predetermined beam by the quadrupole electrostatic lens 6, the beam is scanned in the x-y direction by the action of the electric fields of the vertical scanning plate 7 and the horizontal scanning plate 8, while the irradiation range is limited by the ground mask 9, and the beam is sent to the platen. The object to be processed, for example, the semiconductor wafer 11 placed on the substrate 10 is irradiated with the radiation.

However, in the above-mentioned conventional ion implantation apparatus, since the scanning irradiation of the beam is performed in a fan-like scanning manner, a problem arises in that the beam incidence angle differs depending on the part of the substrate to be ion implanted, and uniform ion implantation cannot be performed. For example, the beam incidence angle differs between the central part and the peripheral part of the semiconductor wafer to which the ion beam is irradiated, making it impossible to perform uniform ion implantation over the entire surface of the semiconductor wafer.

(Problems to be Solved by the Invention) As described above, fan-shaped scanning irradiation has a problem in that the state of ion implantation varies depending on the portion of the substrate to be ion implanted.

In order to solve these problems, parallel irradiation scanning (hereinafter referred to as parallel scanning) of ion beams has been proposed in recent years, but it is difficult to scan ion beams in parallel with high precision. , and it has not been realized yet because it would increase the size of the device and significantly increase the manufacturing cost.

Therefore, in order to scan the ion beam in parallel with high precision, the present inventor conducted research on controlling the deflection of the ion beam by installing multiple deflection systems in the ion implanter, and found that it was possible to provide multiple deflection systems. It has been found that this causes various problems.

For example, in order to convert an ion beam into a parallel beam, we conducted research and experiments in which an ion beam that was deflected horizontally and vertically by a primary deflection system was converted into a parallel beam by a secondary deflection system. After passing through the primary deflection system, it is scanned at a predetermined angle, so depending on this scanning angle,
In addition, if an abnormality occurs in the control of the primary deflection system, the secondary
It was found that the ion beam irradiates the secondary deflection system, etc., which tends to cause problems.

The present invention was made based on this knowledge, and has a simple structure that realizes highly accurate parallel scanning of ion beams and prevents problems caused by erroneous irradiation of deflection systems, etc. It is an object of the present invention to provide an ion implantation device that is highly reliable and enables a significant improvement in uniformity in ion implantation work.

[Structure of the Invention] (Means for Solving the Problems) That is, the present invention provides an ion implantation apparatus that scans and irradiates an ion beam onto a workpiece to implant ions into the workpiece, in which the ion beam is horizontally and a first electrostatic deflection system that deflects the ion beam in the vertical direction; a ground mask that regulates the passing position of the ion beam deflected in the horizontal and vertical directions by the first electrostatic deflection system; A second electrostatic deflection system comprising an electrostatic deflection electrode that converts the horizontal component of the regulated ion beam into a parallel beam, and an electrostatic deflection electrode that converts the vertical component of the beam into a parallel beam. There is.

(Function) In the ion implantation apparatus of the present invention, the ion beam that has been electrostatically scanned in the vertical and horizontal directions is deflected by the second electrostatic deflection electrode, which separates the beam horizontal direction component and the beam vertical direction component, respectively. Since parallel scanning is performed using an electrostatic deflection system, it is possible to easily and accurately create parallel beams. In addition, since a ground mask is provided behind the first electrostatic deflection system, the passage position of the ion beam is regulated before it is incident on the second electrostatic deflection system, and the ion beam passes through the second electrostatic deflection system. erroneous irradiation is prevented.

(Example) Hereinafter, an example in which the present invention is applied to a medium current type ion implantation device will be described with reference to the drawings.

Note that FIG. 1(a) is a plan view of one embodiment, and FIG. 1(b) is a plan view of one embodiment.
shows its side view.

The ion beam 21 is outputted from an ion source (not shown) and shaped into a desired beam shape by an analysis magnet, an accelerator tube, an electrostatic lens, etc. (not shown).
A first scanning plate 22 consisting of a scanning plate 22 (hereinafter referred to as the y direction) and a scanning plate 23 in the horizontal direction (hereinafter referred to as the X direction).
The light then enters the electrostatic deflection system 24.

A voltage based on a scanning signal which is a triangular wave having a frequency of, for example, L12.19Hz and 1OL9Hz is applied to the X-direction scanning plate 22 and the X-direction scanning plate 23, respectively, and the change in the electric field between each electrode at this time causes the incident Scanning irradiation of the beam is performed by deflecting the ion beam 21 in a predetermined direction.

In addition, in the X-direction scanning plate 23, the applied voltage is controlled so that the ion beam 21 is bent at an offset angle θ, for example 7 degrees, with respect to the beam traveling axis, and neutral ions mixed in the ion beam 21 are controlled. Miscellaneous ions such as ions are sorted out at this beam bending part and fly in a direction different from the desired ions, for example, in a straight direction 25.

The miscellaneous ions selected above, such as neutral ions, are
The neutral ions collide with a shielding plate 26 made of carbon, for example, disposed in the flight direction 25, and are prevented from entering the object to be processed.

A first ground mask 27 made of carbon, for example, is provided behind the primary electrostatic deflection system 24 in the beam traveling direction. As shown in FIGS. 2(a) and 2(b), the ion beam that has passed through the primary electrostatic deflection system 24 is directed to the first ground regardless of the scanning angle by the primary electrostatic deflection system 24. The mask 27 prevents erroneous irradiation onto the secondary electrostatic deflection system 31, which will be described later, etc. (for example, the area indicated by diagonal lines in the figure).

) The passing position is regulated in each of the X direction and the X direction.

The size of the opening of the first ground mask 27 is preferably determined by taking into account the maximum scanning width allowable by the secondary electrostatic deflection system 31. There is no need for this.

The ion beam whose passage position is regulated by the first ground mask 27 passes through the secondary electron suppression electrode 28 and
The light enters a second electrostatic deflection system 31 consisting of a direction deflection plate 29 and an X direction deflection plate 30.

A reverse bias voltage is applied to the X-direction deflection plate 29 almost in synchronization with the X-direction scanning plate 22, and the incident ion beam 21 is slightly repelled toward the center between the electrodes of the X-direction deflection plate 29. and is converted into a parallel beam in the X direction.

The ion beam 21 a that has been converted into a parallel beam in the X direction by the X direction deflection plate 29 then enters the X direction deflection plate 30 . A reverse bias voltage is also applied to the X-direction deflection plate 30 in almost synchronization with the X-direction scanning plate 23, and parallel beams can also be formed in the X-direction using the same principle as the X-direction deflection plate 29. be done.

In this way, the ion beam that has passed through the secondary electrostatic deflection system 31 becomes an ion beam 21b that is parallelized to the X 1 direction, and passes through the beam adjustment mechanism 32 and the second ground mask 33. The beam is then scanned and irradiated onto an object to be processed, such as a semiconductor wafer 35, placed on a platen 34. The semiconductor wafer 35 is tilted at a tilt angle of, for example, approximately 7 degrees with respect to the beam irradiation axis for the purpose of preventing channeling. ing.

In addition, a ground electrode 3 is arranged on the ion beam irradiation axis so as to sandwich each deflection plate 29, 30 of the secondary electrostatic deflection system.
6.37.38 are for preventing the electric field from sagging at the ends of each deflection plate 29.30.

In this way, by converting the ion beam 21 into parallel beams and performing scanning irradiation, the semiconductor wafer 35 can be uniformly implanted with ions. In addition, since the passage position of the ion beam scanned and irradiated at a predetermined angle by the first electrostatic deflection system 24 is regulated by the first ground mass 27, the control voltage of the first electrostatic deflection system is Even if an abnormality occurs,
Erroneous irradiation of the deflection electrodes and the like of the second electrostatic deflection system 31 is prevented. Therefore, control abnormalities of the second electrostatic deflection system 31 can be prevented, and stable and good parallel scanning can be performed.

In the above-described embodiment, if the voltage application to the secondary electrostatic deflection system 31 is stopped, conventional narrow scanning can also be performed, and a desired beam scanning method can be selected depending on the processing content.

[Effects of the Invention] As explained above, the ion implantation device of the present invention, despite its simple structure, enables parallel scanning of ion beams and prevents erroneous irradiation to electrostatic deflection systems, etc. Because of this, parallel scan control can be performed stably, which can greatly contribute to improving uniformity in ion implantation processing operations.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention.
a) is a plan view of the embodiment, FIG. 1(b) is a side view thereof, FIG. 2 is a diagram showing the main parts of FIG. ) is a side view thereof, and FIG. 3 is a diagram showing the configuration of a conventional ion implantation apparatus. 21...Ion beam, 22...X direction scanning plate, 23...X direction scanning plate, 24...
... Primary electrostatic deflection system, 26 ... Neutral beam shielding plate, 27 First ground mask, 29 ...
...X-direction deflection plate, 30...X-direction deflection plate, 31...Second electrostatic deflection system, 34...
・Platen, 35...Semiconductor Ueno 1゜Applicant Chiru Parian Co., Ltd. Agent Patent Attorney Sasu Suyama −

Claims (1)

[Scope of Claims] An ion implantation apparatus that scans and irradiates an ion beam onto a workpiece to implant ions into the workpiece, comprising: a first beam that deflects the ion beam in horizontal and vertical directions;
an electrostatic deflection system, a ground mask that regulates the passing position of the ion beam deflected in the horizontal and vertical directions by the first electrostatic deflection system, and a ground mask that regulates the passing position of the ion beam that is horizontally and vertically deflected by the first electrostatic deflection system; An ion implantation apparatus comprising: a second electrostatic deflection system including an electrostatic deflection electrode that converts directional components into a parallel beam; and an electrostatic deflection electrode that converts vertical components of the beam into a parallel beam.