JP3104075B2 - Ion implantation apparatus and ion implantation method - Google Patents

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 implanting ions into a semiconductor wafer.

[0002]

2. Description of the Related Art As a conventional ion implantation apparatus, XY is used.
A scanning type apparatus and an apparatus described in JP-A-2-24948 are known. However, with the recent increase in the diameter of the wafer (to 8 inches), the medium-current ion implantation apparatus has shifted from the XY scanning method to the wafer to improve the incident angle and in-plane uniformity. There is a shift to a system having a means for moving (mechanical scanning) a wafer in a direction intersecting the one direction with a parallel ion beam irradiation means moving in a direction (parallel scanning).

[0003]

In such an ion implantation apparatus, the charge-up phenomenon on the wafer surface which occurs during the ion implantation causes the withstand voltage of the gate oxide film to deteriorate,
It is known to cause problems such as destruction of patterns and deterioration of in-plane uniformity. In particular, the conventional XY scanning type medium current ion implanter uses the electrostatic induction type charge monitor used in the high current ion implanter to collectively implant ions into the entire surface of the wafer. It could not be easily monitored during ion implantation.

In the above-mentioned medium-current ion implantation apparatus of the parallel scanning + mechanical scanning, which has become the mainstream in recent years, the influence of the charge-up phenomenon is required to increase the current and increase the diameter for improving the throughput. There is concern.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide an ion implantation apparatus capable of preventing device characteristics deterioration and destruction due to charge-up.

[0006]

Means for Solving the Problems] according parallel ion beam irradiation means for moving in one direction relative to section 1 of the substrate, the direction to the substrate single wafer ion implantation and a means for moving the intersecting said one direction In the apparatus, the device interferes with the ion beam in the vicinity of the substrate and in the vicinity of the ion beam.
And a charge sensor disposed at a position where no charge sensor is provided. A flat plate which moves in one direction with respect to the substrate of claim 2.
Row ion beam irradiation step, in a direction intersecting with the one direction
Moving the substrate.
And facing the substrate and near the ion beam,
A char arranged at a position not to interfere with the ion beam
Di-sensor to detect charge-up on the substrate surface
It is characterized by being able to .

[0007]

The charge sensor disposed in the vicinity (for example, above or below) of the ion beam irradiated on the substrate by the parallel ion beam irradiation means can measure the charge amount without interfering with the ion beam. Will be possible. Further, the closer the charge monitor is to the base, the higher the measurement accuracy can be.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the ion implantation apparatus according to the present invention will be described with reference to the embodiments shown in the drawings.

As shown in FIG. 1, the ion implantation apparatus according to the present embodiment includes a parallel ion beam irradiation means 1 for irradiating an ion beam a, a platen 3 for supporting a wafer 2 as a base, and a lower portion of the platen 3. Drive shaft 4 provided integrally with
Lifting drive means 5 for raising and lowering the platen 3 via the
And an electrostatic induction type charge monitor 6 arranged near the lower portion of the ion beam a.

The parallel ion beam irradiating means 1 scans the ion beam drawn from the ion source side with a deflection electrode, converts it into a parallel beam with a dipole lens, accelerates an ion beam a with an acceleration tube, and implants ions into a wafer 2. It has become. FIG. 2 shows a state in which the ion beam a is irradiated toward the wafer 2.
Scanning is performed in the horizontal direction (x direction in the figure).

As shown in FIG. 1, the parallel ion beam irradiation means 1 is maintained at a predetermined beam width by passing through a slit 8 between the masks 7, 7.

Since the charge monitor 6 is disposed below the vicinity of the ion beam a, when the platen 3 is lowered by the elevation driving means 5, it is possible to measure the charge amount on the surface of the wafer 2 immediately after the ion beam irradiation. It is possible. Electron irradiation is performed on the surface of the wafer 2 based on the charge amount measured by the charge monitor 6 to sufficiently neutralize the charge on the surface of the wafer 2.

In this embodiment, the charge monitor 6 is disposed below the ion beam a. However, the charge monitor 6 may be disposed above the ion beam a to evaluate a charge amount when the wafer 2 moves upward. Alternatively, the charge sensors 6 may be provided near the upper and lower portions of the ion beam a.

In the above embodiment, the charge sensor 6 is provided at a position close to the mask 7 as shown in FIG. 1, but a support structure for the charge sensor 6 is separately provided so as to be closer to the surface of the wafer 2. May be provided.

In the present invention, various other design changes can be made along with the gist of the configuration.

[0016]

As is apparent from the above description, in the ion implantation apparatus according to the present invention, in the system in which the mechanical scanning is added to the parallel scanning, it is possible to detect the charge-up of the surface of the substrate generated during the ion implantation. Therefore, there is an effect that deterioration and destruction of characteristics of a device formed on the base can be prevented.

Further, there is an effect that it is possible to control the charge neutralizing means such as electron irradiation based on the amount of charge on the substrate surface.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of an ion implantation apparatus according to the present invention.

FIG. 2 is an explanatory view showing an irradiation state of a parallel ion beam according to the embodiment.

[Explanation of symbols]

a: ion beam, 1: parallel ion beam irradiation means, 2
... wafer, 3 ... platen, 5 ... up / down driving means, 6 ... charge monitor.

Claims (2)

(57) [Claims] 1. A single-wafer ion implantation apparatus comprising : a parallel ion beam irradiation unit that moves in one direction with respect to a substrate; and a unit that moves the substrate in a direction intersecting with the one direction. And near the ion beam ,
An ion implanter comprising a charge sensor disposed at a position that does not interfere with the on-beam . (2)Parallel ions moving in one direction relative to the substrate
Beam irradiation step and the base in a direction intersecting with the one direction.
Moving the body, and The ion beam is opposed to the base and in the vicinity of the ion beam.
Charge sensor installed at a position that does not interfere with the on-beam
The charge up of the substrate surface can be detected by the
An ion implantation method, characterized in that: