JPH07307138A - Ion implanting device - Google Patents

Abstract

PURPOSE:To prevent an error or beam current measurement even if insulating performance of insulators for insulating a center suppressor electrode is deteriorated by switching the center suppressor electrode to a side of a center Faraday cylinder when an ion beam is radiated on a base board on a holder so as to implant an ion. CONSTITUTION:When a beam current of an ion beam 2 is measured by using a center Faraday cylinder 22, a negative voltage is applied to a center suppressor electrode 20 from a suppressor power source 26 so that an original function of the electrode 20, i.e., a function of restricting secondary electron emission from the center Faraday cylinder 22 can be exhibited since the electrode 20 is switched on a side of the power source 26. Meanwhile, when an ion is implanted by radiating the ion beam 2 to a base board 6 on a holder 8, no voltage is applied to the electrode 20 from the power source 26 since the electrode 20 is switched on a side of the Faraday cylinder 22. Consequently, no leak current flows in a beam current measuring device 24 via insulators 18, 16 from the power source 26 even if insulating performance of the insulators 18, 16 for insulating the electrode 20 is deteriorated due to a stain or the like, thereby preventing generation of an error of beam current measurement by the measuring device 24 at the time of ion implantation.

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, and more specifically, to improvement of a beam current measuring system for the ion beam.

[0002]

2. Description of the Related Art FIG. 2 is a schematic sectional view showing an example of a conventional ion implantation apparatus. This ion implantation apparatus basically applies an ion beam 2 scanned by a scanning unit (not shown) to a substrate (for example, a wafer) 6 mounted on a holder 8 for holding a substrate provided in a vacuum container (not shown). It is configured to irradiate and perform ion implantation.

The holder 8 is rotated by a rotating shaft 10 between an upright state and a tilted state as shown by an arrow A in order to attach and detach the substrate 6.

On the upstream side of the holder 8, secondary electrons emitted when the ion beam 2 hits the substrate 6 and the holder 8 are prevented from escaping to the ground to accurately measure the beam current of the ion beam 2. A main Faraday 4 is provided to do this.

Further, on the upstream side of the holder 8 in the main Faraday 4, there is a plate-shaped center flag 12 which is rotated by a rotating shaft 14 between an upright state and a tilted state as shown by an arrow B, and an opening 12a. Is provided.

The opening 12a of the center flag 12
A center suppressor electrode 20 having an opening 20a is provided on the back side of the via a ceramic insulator 16.
A negative voltage (for example, about −100 V to −600 V) is applied to the center suppressor electrode 20 from the suppressor power supply 26. This center suppressor electrode 20
Is the center Faraday 22 which the ion beam 2 will be described later.
This is for suppressing secondary electrons emitted when hitting, and for accurately measuring the beam current of the ion beam 2 by the center Faraday 22.

The opening 20 of the center suppressor electrode 20
A center Faraday 22 for receiving the spot-shaped ion beam 2 through the insulator 18 and measuring the beam current thereof is provided on the back side of a.

A beam current measuring instrument 24 such as a current integrator is connected to the center Faraday 22. The beam current measuring device 24 is also connected to the main Faraday 4, the holder 8 and the center flag 12 via a switch 28.

To explain an example of operation, the ion beam 2 is usually adjusted prior to ion implantation into the substrate 6. Specifically, the center flag 12 is set in a vertical state, the spot-shaped ion beam 2 that is not scanned is received by the center Faraday 22, and the current flowing therethrough is measured by the beam current measuring device 24 to measure the beam of the ion beam 2. The current is measured, or the scanned ion beam 2 is received by the center flag 12, and the scanning waveform of the ion beam 2 is adjusted. In the former case, the switch 28 is opened, and in the latter case, the switch 28 is closed.

When the ion implantation into the substrate 6 is completed after the adjustment of the ion beam 2, the center flag 12 is tilted horizontally, and the holder 8 is placed vertically instead, and the substrate 6 is scanned with the ion beam 2. While irradiating. At this time, the switch 28 is closed and the beam current of the ion beam 2 with which the substrate 6 is irradiated is measured by the beam current measuring device 24 to measure the implantation amount (dose amount) to the substrate 6.

In the above case, the ion beam can be extracted from the ion source by turning on a switch of a high voltage power source (not shown) for applying a high voltage to the ion source, that is, beam adjustment. In both cases of inside and ion implantation, the negative voltage as described above is always applied to the center suppressor electrode 20 from the suppressor power supply 26.

[0012]

In such an ion implantation apparatus, the center suppressor electrode 20 is insulated during use of the apparatus by sputtered particles generated by the ion beam 2 hitting the center Faraday 22 and the like. Contamination is generated on the insulating insulator 18 and further on the insulating insulator 16 and their insulating performance is deteriorated, and the beam current measuring device is passed from the center suppressor electrode 20 via the insulating insulator 18 and the center Faraday 22. 24, or from the center suppressor electrode 20 to the beam current measuring device 24 via the insulator 16, the center flag 12 and the switch 28, a leak current in the direction opposite to the beam current of the ion beam 2 flows, which causes the beam current. Error in measuring the beam current of the ion beam 2 by the measuring instrument 24 There is a problem that arises.

The measurement error of the beam current due to such a leak current should be avoided because it causes an injection defect (dose error) not only during the beam adjustment but also during the ion implantation into the substrate 6.

Therefore, in the present invention, even if the insulation performance of the insulator that insulates the center suppressor electrode is deteriorated, an error does not occur in the beam current measurement by the beam current measuring device during ion implantation into the substrate. The main purpose is to provide an ion implantation apparatus.

[0015]

To achieve the above object, the ion implanter of the present invention is provided with a switcher for switching and connecting the center suppressor electrode as described above between the suppressor power source side and the center Faraday side, Therefore, when measuring the beam current using the center Faraday, the center suppressor electrode is switched to the suppressor power supply side, and when performing ion implantation by irradiating the substrate on the holder with the ion beam, move the center suppressor electrode to the center Faraday side. The feature is that they are switched.

[0016]

According to the above construction, when the substrate on the holder is irradiated with the ion beam for ion implantation, the center suppressor electrode is switched to the center Faraday side.
No voltage is applied to the center suppressor electrode from the suppressor power supply. Therefore, even if the insulation performance of the insulator that insulates the center suppressor electrode deteriorates, the leak current does not flow to the beam current measuring instrument. Therefore, the beam current measuring instrument can measure the beam current during ion implantation. Error does not occur.

[0017]

1 is a schematic sectional view showing an ion implantation apparatus according to an embodiment of the present invention. The same or corresponding portions as those of the conventional example in FIG. 2 are denoted by the same reference numerals, and the differences from the conventional example will be mainly described below.

In this embodiment, the center suppressor electrode 2 is provided between the center suppressor electrode 20 and the suppressor power supply 26 which applies a negative voltage thereto.
0 is provided between the suppressor power supply 26 side and the center Faraday 22 side for connection, and when the beam current of the ion beam 2 is measured using the center Faraday 22 by the switcher 30, the center suppressor electrode 20 is provided. Is switched to the suppressor power supply 26 side, and the center suppressor electrode 20 is switched to the center Faraday 22 side when the substrate 6 on the holder 8 is irradiated with ions to perform ion implantation.

The switch 30 may be a relay or other switch.

The switching of the switching device 30 as described above may be performed by control by a control system that controls the entire ion implantation apparatus, or may be performed by a human operation.

According to the above configuration, the center Faraday 2
When measuring the beam current of the ion beam 2 using the S.2, the center suppressor electrode 20 is connected to the suppressor power supply 26.
Since the center suppressor electrode 20 is switched to the side, a negative voltage is applied to the center suppressor electrode 20 from the suppressor power supply 26, and the original function of the center suppressor electrode 20, that is, the effect of suppressing secondary electron emission from the center Faraday 22 can be achieved. Therefore, there is no problem in measuring the beam current of the ion beam 2 using the center Faraday 22.

On the other hand, when irradiating the substrate 6 on the holder 8 with the ion beam 2 to perform ion implantation, the center suppressor electrode 20 is switched to the center Faraday 22 side, so that the center suppressor electrode 20 receives a voltage from the suppressor power supply 26. Is not applied. Therefore, even if the insulation performance of the insulators 18 and 16 that insulate the center suppressor electrode 20 is deteriorated due to dirt or the like, the leakage current from the suppressor power supply 26 to the beam current measuring device 24 via the insulators 18 and 16 is reduced. Does not flow, and therefore, no error occurs in the beam current measurement by the beam current measuring device 24 at the time of ion implantation. Therefore, it is possible to prevent the implantation failure (dose error) from occurring in the substrate 6.

When ion-implanting the substrate 6,
Center suppressor electrode 20 to center Faraday 22
There is also an idea to electrically float the center suppressor electrode 20 instead of connecting it to the center suppressor electrode 20. However, if the center suppressor electrode 20 is electrically floated, the main Faraday 4 will not be discharged during injection. The center suppressor electrode 20 may be negatively charged due to the presence of a large number of secondary electrons, and discharge may occur due to this, which may adversely affect the beam current measurement by the beam current measuring device 24. Therefore, it is preferable to fix the potential by connecting the center suppressor electrode 20 to the center Faraday 22 rather than electrically floating the center suppressor electrode 20.

[0024]

As described above, according to the present invention, when the substrate on the holder is irradiated with an ion beam for ion implantation, the center suppressor electrode is switched to the center Faraday side. Therefore, the suppressor is attached to the center suppressor electrode. No voltage is applied from the power supply. Therefore, even if the insulation performance of the insulator that insulates the center suppressor electrode deteriorates, the leak current does not flow to the beam current measuring instrument, and therefore the beam current measuring instrument measures the beam current during ion implantation. Error does not occur. Therefore, it is possible to prevent the injection failure from occurring in the substrate.

[Brief description of drawings]

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

FIG. 2 is a schematic cross-sectional view showing an example of a conventional ion implantation device.

[Explanation of symbols]

 2 Ion beam 4 Main Faraday 6 Substrate 8 Holder 12 Center flag 16, 18 Insulator 20 Center suppressor electrode 22 Center Faraday 24 Beam current measuring device 26 Suppressor power supply 30 Switching device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical indication H01L 21/265

Claims (1)

[Claims] 1. A holder for holding a substrate to be ion-implanted, and a plate-shaped center flag which is provided on the upstream side of the holder and can be rotated between an upright state and a tilted state and has an opening. A center suppressor electrode provided on the back side of the opening of the center flag via an insulator and having an opening, and a center suppressor electrode provided on the back side of the opening of the center suppressor electrode via an insulator Center Faraday for receiving the ion beam and measuring the beam current, a beam current measuring device for measuring the beam current flowing through the center Faraday, etc., and a suppressor power supply for applying a negative voltage to the center suppressor electrode. In the ion implantation apparatus including the center suppressor electrode, the center suppressor electrode and the center Faraday When the beam current is measured using the center Faraday, the center suppressor electrode is switched to the suppressor power supply side, and the ion beam is irradiated onto the substrate on the holder to perform ion implantation. The ion implanter is characterized in that the center suppressor electrode is switched to the center Faraday side when performing.