JPH04123754A - ion implanter - Google Patents

Abstract

PURPOSE:To control the ion beam dose to become a prescribed level by observing the ion beam dose all the time including the injection time. CONSTITUTION:Ion beams 5 coming out of an ion source 1 are led to a magnet 2 for separation and separated into the ion beam 5 to be implanted and the other not to be implanted, and the ion beam 5 is ion-implanted into a substrate 4. The beam 5 is measured as electric current of the ion passing amount by a d.c. transformer 7 installed in the outside of a vacuum container. The ion beam amount is thus observed all the time including the time of implantation by this indirect measurement and the ion source can be controlled as the real time, so that the ion implantation amount can precisely be made uniform on the substrate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for measuring the amount of ion beam in an ion implanter, and an ion implanter using this measurement value. The system was equipped with a Faraday tube, and the ion beam was introduced into the Faraday tube before ion implantation, the ion beam amount was adjusted, and the ions were implanted after the adjustment. The position of Faraday Katsub is as shown in Figure 2.
Either place it in front of the substrate when measuring the ion beam amount and move it during ion implantation, or install a deflection magnet as shown in Figure 3.

When measuring the amount of ion beam, there is a method in which the ion beam is deflected to a Faraday tube outside the substrate.

The former method is described in, for example, "Example of Structure of Electron/Ion Beam Handbook J" (P587).

Of course, it is possible to constantly measure the amount of ion beam by insulating the substrate and using the substrate itself as a Faraday tube, but in general, the substrate is showered with electrons to neutralize the ions, so this method cannot normally be used.

[Problem to be solved by the invention]

The above conventional technology uses a method of measuring with a Faraday tube before ion implantation, and there are problems such as the ion beam amount cannot be constantly monitored and the ion beam amount changes during long-term ion implantation. Furthermore, it is not possible to change the ion beam amount over time, change the ion implantation amount in the depth direction, or make the ion implantation amount vary in plan.

The purpose of the present invention is to constantly monitor the amount of ion beam, and
An object of the present invention is to provide a control method that controls an ion source based on a monitored amount and makes it possible to keep the amount of ion beam constant or change it.

[Effect]

In order to achieve the above object, the present invention provides means for indirectly measuring the ion beam. Since the ion beam amount is measured indirectly, the ion beam amount can be constantly monitored even during ion implantation, and the ion source can be controlled in real time, so the ion implantation amount can be uniform or varied in the depth direction. You can also add shading on a flat surface.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

An ion beam 5 extracted from an ion source 1 is passed through a separation magnet 2 and separated into an ion beam 5 to be implanted and a beam not to be implanted. A substrate 4 is provided in the traveling direction of an ion beam 5 for ion implantation, and ions are implanted into the substrate. A direct current transformer 7 (commonly known as DCCT) is provided outside the vacuum chamber of the ion beam 5 for ion implantation, and the amount of ion passing is measured as a current. This measured value is the ion beam amount. By feeding back this measured value and controlling the ion source in real time, the amount of ions implanted into the substrate 4 can be made uniform accurately.

Furthermore, the amount of ion beam is constantly monitored.

It can also be changed over time, for example, it is possible to increase the amount of ion beam with a high acceleration voltage and decrease the amount of ion beam with a low acceleration voltage, and it is also possible to create a density of implanted ions in the depth direction. It is. It is also possible to keep the accelerating voltage constant and change the ion beam amount depending on the implantation position on the substrate 4, so that the ion implantation amount can be varied in a two-dimensional manner.

Furthermore, since conventionally a Faraday tube was used, complicated mechanical components had to be provided in a vacuum, resulting in a complicated structure. However, according to the present invention, it is only necessary to provide the DC current transformer 7 outside the vacuum container, and the configuration of the device becomes very simple.

〔Effect of the invention〕

According to the present invention, the ion beam amount can be constantly monitored even during ion implantation, and the ion source can be controlled in real time, so that the ion implantation amount can be accurately made uniform over the substrate.

In addition, even if the ion source is controlled, the amount of ion beam can be measured in real time without having to measure each time with a Faraday tube, so any amount can be emitted, and the amount of ions implanted can be adjusted in the depth direction of the substrate. It is also possible to vary the amount of ion implantation or to vary the amount of ion implantation in a two-dimensional manner.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of an embodiment of the present invention, Fig. 2 is an explanatory diagram of an example in which a conventional Faraday cube is provided in front of a substrate, and Fig. 3 is an explanatory diagram of an example in which a conventional deflection magnet is used to deflect an ion beam to a Faraday cube for measurement. It is an explanatory view of an example. 1... Ion source, 2... Separation magnet, 3... Slit.

Claims (1)

[Claims] 1. In an ion implantation apparatus comprising an ion source, a separation magnet for mass-separating the ion beam output from the ion source, and a substrate into which the ion beam is implanted, the amount of the ion beam to be implanted is controlled by ion implantation. An ion implantation device characterized by being equipped with a device for constant monitoring, including when the device is in use.