JPS62190644A - Ion processing device - Google Patents

Abstract

PURPOSE:To suppress sputtering from a shutter so as to also restrict any pollution on a substrate etc. by installing a means for applying a positive potential to the shutter. CONSTITUTION:A DC power supply 42 is inserted between a shutter 24 and the above-mentioned measuring unit 36, as a means for applying a positive potential to the shutter 24. When the shutter 24 is closed, an ion beam 22 having the energy necessary for processing a substrate 30 fly toward the shutter 24 inside a processing chamber 34. Then, if some positive potential, for instance, a high voltage is applied to the shutter 24, an electric field is generated from the shutter 24 toward an ion extracting electrode system 12, and energy included in the ion beam 22 is reduced due to the function of the electric field. Accordingly, the sputter rate from the shutter 24 is remarkably attenuated so that any pollution on the substrate 30 etc. can be remarkably restricted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ion processing apparatus that processes a substrate using an ion beam, such as an ion beam etching apparatus or an ion implantation apparatus, and particularly relates to an ion processing apparatus that processes a substrate using an ion beam, such as an ion beam etching apparatus or an ion implantation apparatus. This paper relates to improvements to the shutter concavities that interrupt the ion beam.

[Conventional technology]

FIG. 3 is a schematic diagram showing an example of a conventional ion processing apparatus. In this example, a holder 32 is provided in a processing chamber (vacuum container) 34, and a substrate (wafer) 30 to be processed is mounted on the holder 32. In addition, the processing chamber 34
An ion source 2 that emits an ion beam 22 toward the substrate 30 is attached to the ion source 2 .

The ion source 2 is an ECR type ion source in this example, and includes a plasma chamber 8 that generates plasma, a mass flow controller 9 that adjusts the ion source gas G supplied to the plasma chamber 8, and a microwave that is passed through a special wave tube 6 into the plasma chamber 8. It is equipped with a microwave oscillator 4 for supplying electric power, a magnetic field coil 10 for plasma confinement, and an extraction electrode system 12 for extracting an ion beam 22 from the plasma chamber 8. In this example, the extraction electrode system 12 consists of an accelerating electrode I4 and a decelerating electrode 16, and accelerating voltages Va and Vd are applied to both electrodes 14.16 from an accelerating power source 18 and a decelerating power source 20, respectively. As a result, the ion beam 22 is extracted from the ion source 2, and the substrate 1 is irradiated with the ion beam 22 to perform processing such as etching and ion implantation.

On the other hand, between the ion source 2 and the substrate 30, the ion beam 2
A movable shutter 24 is provided that cuts off and on. In this example, the shunter 24 is equipped with a cooling section 26 on its back surface, and the substrate 30 is cooled by means not shown.
When processing the ion beam 22, place it in a position that does not obstruct the passage of the ion beam 22, and at other times, such as when adjusting the beam current of the ion beam 22 before processing or replacing the substrate 30. It is driven to the cutoff position, for example, in a straight line or in an arc. In addition, ion beam 2
In this example, the beam current {circle around (2)} is measured by a measurement unit 36 that is connected to the shutter 24 and includes a grounding resistor 38, an amplifier 40, and the like.

[Problem that the invention seeks to solve]

In the above-mentioned apparatus, when the shutter 24 is closed to block the ion beam 22, the ion beam 22 directly hits the shutter 24 and sputters its surface, so that the sputtered particles are scattered on the substrate 30, the inner wall of the processing chamber 34, It adheres to the extraction electrode system 12 of the ion source 2 and contaminates them.

In particular, contamination of the substrate 30 has a fatal impact on, for example, the production of VLS1.

In order to avoid this, conventionally, the material of the shutter 24 has a low spatter rate (at
oms/1on), however, the current situation is that sputtered particles are still mixed into the substrate 30 and have an adverse effect.

Therefore, an object of the present invention is to suppress the sputtering of the shutter as described above.

[Means for solving problems]

The ion processing apparatus of the present invention includes a vacuum container, an ion source that emits an ion beam toward a substrate housed in the vacuum container, and a movable shutter that cuts off the ion beam. It is characterized by providing means for applying a positive potential to the shutter.

[Effect]

By applying a positive potential to the shutter, the energy of the ion beam near the shutter surface is reduced.

As a result, the sputtering rate of the shutter decreases.

〔Example〕

FIG. 1 is a schematic diagram showing an ion processing apparatus according to an embodiment of the present invention. Components equivalent to those in FIG. 3 are given the same reference numerals and their explanations will be omitted.

In this embodiment, as means for applying a positive potential to the shutter 24, a DC type 'rA42 is inserted between the shutter 24 and the measurement unit 36 mentioned above. The DC power supply 42 is a variable voltage power supply in this example, and is controlled by a control circuit 44 to generate a voltage V according to the acceleration voltage Va.
It is designed to output s. It goes without saying that even if the DC power supply 42 is inserted as described above, no problem will arise in the measurement of the beam current (2) of the ion beam 22 by the measurement unit 36.

In the above device, the ion beam 22 is e.g.
More specifically, the extraction electrode system 12
It is adjusted by the accelerating voltage Va etc. applied to. Therefore, when the shutter 24 is closed, the ion beam 22 with this energy passes through the shutter 24 inside the processing chamber 34.
fly towards.

However, since a positive, for example, high potential is applied to the shutter 24 as described above, an electric field is generated from the shutter 24 toward the extraction electrode system 12. When a positively charged particle such as the ion beam 22 flies through an electric field, the energy of the particle decreases due to the action of the electric field.

In this case, the ion beam 22 incident on the shutter 24
The sputtering rate of Shack-24 with respect to the energy of is
Although there are differences depending on the types of ion beams 22 and shutters 24, they generally show a tendency as shown in FIG. 2, and have a peak near a certain energy.

Therefore, by sufficiently reducing the energy of the ion beam 22 incident on the shutter 24 as described above, the sputtering rate of the shutter 24 is significantly reduced. As a result, 7η staining on the substrate 30 and the like is significantly suppressed.

In the above case, the output voltage Vs of the DC power supply 42 is fixed, that is, the DC power supply 42 is a fixed voltage power supply, and the control circuit 44 is not provided (although it is possible to vary the energy of the ion beam 22 extracted from the extraction electrode system 12). In such a case, for example, as in this example, the accelerating voltage Va (or a voltage corresponding to it) is input to the control circuit 44, and the output voltage Vs of the DC power supply 42 is controlled via the control circuit 44 based on the accelerating voltage Va. It is convenient if the energy of the ion beam 22 incident on the shutter 24 is controlled to be an appropriate value, that is, a value smaller than the spackle ratio by J'X.

Note that the structure of the ion source 2, the structure of the shutter 24, the driving method thereof, the means for holding the substrate 30, etc. described above are merely examples, and are not necessarily limited to those described above.

〔Effect of the invention〕

As described above, according to the present invention, sputtering of the shutter due to the ion beam is suppressed, and contamination of the substrate and the like is also suppressed accordingly.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an ion processing apparatus according to an embodiment of the invention. FIG. 2 is a schematic diagram showing the direction of the sputtering rate relative to the energy of the ion beam. FIG. 3 is a schematic diagram showing an example of a conventional ion processing apparatus. 2... Ion source, 22... Ion beam, 2431
．． Shutter, 30..., substrate (wafer), 34...
Processing chamber (vacuum container), 42..., DC power supply, 44...
control wholesale circuit

Claims (1)

[Claims] (1) In an apparatus comprising a vacuum vessel, an ion source that emits an ion beam toward a substrate housed in the vacuum vessel, and a movable shutter that cuts off and on the ion beam, An ion processing device characterized by being provided with means for applying a potential.