JPS6215743A - Ion processor - Google Patents

Abstract

PURPOSE:To achieve a high eficiency of ion beam utilization even if the cross- sectional area of an ion beam is increased, by shaping as arc the cross section of the ion beam pull-out portion of each electrode which functions to pull out the ion beam from an ion source. CONSTITUTION:The cross section of at least the ion beam pull-out portion of each of the pull-out electrode 16 and deceleration electrode 18 of a pull-out electrode system 14 is shaped as arc. An ion beam 20 having an arc-shaped cross section of about W2 and L2 in width and length is pulled out from an ion source 2 having the electrodes, so that the beam is irradiated upon a wafer 24 on a disk 22. Since the inner and outer arcs 201, 202 of the cross section of the ion beam 20 are shaped nearly along envelopes 242, 241 on the outsides and insides of the wafers 24, respectively, the width SW2 of relative scanning with the ion beam can be reduced. A high efficiency of beam utilization can thus be achieved even if the cross-sectional area of the ion beam 20 is increased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ion processing apparatus that processes a sample by irradiating an ion beam onto a sample mounted on a disk that is rotated and translated in a vacuum. This invention relates to an improvement in the shape of the electrode of the ion source of the device.

[Conventional technology]

Examples of ion processing equipment include ion implantation equipment, ion deposition thin film forming equipment that uses both ion implantation and vacuum deposition, and ion beam etching equipment. In the following, an ion beam etching apparatus will be explained as an example.

FIG. 4 is a schematic cross-sectional view showing an example of a conventional batch type ion beam etching apparatus. In the vacuum container 26,
A disk 22 is provided which is rotated as shown by arrow A and translated as shown by arrow B by a disk rotation/translation mechanism 28. A plurality of wafers (sample) 24 are mounted. Then, each wafer 24 is irradiated with an ion beam 20 from the ion source 2 to process the wafer 24, for example, in this example, to etch it.

The ion source 2 is an ECR type ion source in this example, and includes a plasma chamber 8 that generates plasma, a gas supply source 12 that supplies an active gas thereto, and a microwave power supplied to the plasma chamber 8 through a waveguide 6. Microwave oscillator 4, magnetic field coil 10 for plasma confinement, and plasma chamber 8
Extraction electrode system 1 for extracting the ion beam 20 from
4, and the extraction electrode system 14 in this example includes:
It consists of an extraction electrode (also called an accelerating bridge or a plasma electrode, hereinafter the same) 16 for extracting the ion beam 20 and a deceleration electrode 18 for repelling electrons from downstream.

The disk rotation/translation mechanism 28 includes a stepping motor 30 that translates the disk 22 via a mechanism section 32, an induction motor 34 that rotates the disk 22 at high speed, and a vacuum seal section 36. In this case, the translation speed V of the disk 22 is controlled so as to satisfy the following relationship in order to process each wafer 24 uniformly.

v cICI / R Here, ■ is the beam current of the ion beam 20, and R is the distance between the center of the ion beam 20 and the center of the disk 22.

5 is a schematic plan view showing the area around the disk of the apparatus shown in FIG. 4. FIG. Disc 22 rotated as shown by arrow A
Each of the upper wafers 24 sequentially passes through the irradiation area of the ion beam 20, and the ion beam 20 is relatively scanned by the translation of the disk 22 as shown by arrow B. In this case, the scanning width SWI is determined by the distance to a point where the ion beam 20 no longer hits the wafer 24 during scanning.

In addition, the extraction electrode system 14 of the ion beam 20 and the ion source 2
When viewed two-dimensionally, they have almost the same shape and are located in almost the same position.

[Problem that the invention seeks to solve]

Extraction electrode system 1 of the ion source 2 in the device as described above
Conventionally, the planar shape of 4 has been square or rectangular, for example, and in such a case, when trying to increase the beam amount by increasing the electrode area, it is necessary to increase the width or vertical length of the electrode. need to be increased.

However, the width of the electrode, that is, the width W of the ion beam 20,
As SWI increases, the scanning width SWI becomes significantly larger. Furthermore, if the length of the electrode, that is, the length Ll of the ion beam 20 is increased and becomes larger than the diameter of the wafer 24 as shown in FIG. 20 must be scanned relatively, the scanning width SW becomes large in this case as well.

Therefore, in either case, the beam utilization efficiency (=total area of the wafer/total irradiation area of the ion beam) decreases due to an increase in the scanning width SWI.

Therefore, an object of the present invention is to provide an ion processing apparatus that can obtain high beam utilization efficiency even when the beam shape is increased.

[Means for solving problems]

The ion processing apparatus of the present invention is characterized in that at least the ion beam extraction portion of the electrode of the ion source, which is involved in ion beam extraction, has an arcuate planar shape.

[Effect]

Since at least the ion beam extracting portion of the electrode of the ion source has an arcuate planar shape, the ion beam can also have an arcuate planar shape. Therefore, even when the beam shape is increased, the width of the translation of the disk, that is, the relative scanning width of the ion beam can be reduced, and as a result, a high beam utilization efficiency can be obtained.

〔Example〕

FIG. 1 is a schematic plan view showing the area around a disk of an ion beam etching apparatus according to an embodiment of the present invention. Since the other parts are the same as those in FIG. 4, illustration and explanation will be omitted.

In this embodiment, the planar shape of at least the ion beam extraction portion of the electrodes involved in extraction of the ion beam 20 of the ion source 2, that is, the extraction electrode 16 and the deceleration electrode 18 of the extraction electrode system 14 in this example, is arcuate. As a result, the shape of the ion beam 20 extracted therefrom is also arcuate as shown in the figure.

To explain a more specific example, as shown in FIG. 2, the planar shape of the extraction electrode 16 has a substantially constant width W2, and a radius R2 of an inner arc 161 and a radius R3 of an outer arc 162.
together with the radius R of each wafer 24 to the center of the disk 22
I (i.e., R1#R2#R3
), whose length R2 is larger than the diameter of the wafer 24. A small hole 163 for extracting the ion beam 20 is provided on one side of the extraction electrode 16.

The deceleration electrode 18 also has the same structure as the extraction electrode 16.

Therefore, from the ion source 2 having the electrode shape as described above,
As shown in FIG. 1, an arc-shaped ion beam 20 with a width of approximately W2 and a length of approximately R2 is extracted, and this is attached to the disk 2.
The wafer 24 on the wafer 2 is irradiated with light. In this case, both the inner arc 201 and the outer arc 202 of the ion beam 20 are shaped approximately along the envelope 242 connecting the outside of each wafer 24 and the envelope 241 connecting the inside of each wafer 24, so that the relative ion beam The scanning width SW2 of 20 can be made smaller than the scanning width SWI in the conventional case, and thereby, even when the shape of the ion beam 20 is made large as shown in the figure, a high beam utilization efficiency can be obtained.

For example, the width W+=Wz=80 mm of the ion beam 20,
Length LI=L2=300mm, radius RI of wafer row=3
45 mm, the radius r of the wafer 24 is 75 mm, and the number of wafers 24 is 13. Conventionally, the beam utilization efficiency (in the case of FIG. 5) was about 40%, but in this embodiment, it is about 45%. %. Moreover, such an improvement in beam utilization efficiency also leads to an improvement in throughput (number of wafers processed per unit time) in processing (for example, etching) the wafers 24.

In addition, the inner arc 1 of the extraction electrode 16 or the deceleration electrode 18
61 radius R2 and the radius R3 of the outer arc 162 are respectively the radius R5 (=R
I+r) and the radius R4 of the inner envelope 241 (=RI
r) (i.e., R2″−R3
, R1ζR4), so that the inner arc 201 and outer arc 202 of the ion beam 20 almost completely follow the envelopes 242 and 241, respectively,
This allows the scanning width SW2 to be minimized.

Note that the type of ion source 2, the number of electrodes involved in extracting the ion beam 20, etc. are not limited to those described above. For example, an ion source as shown in FIG. 3 may be used. This ion source is a so-called packet-type ion source, and generates and confines plasma using an arc chamber 40, a filament 42, a magnet 44, etc., and an extraction electrode system consisting of an extraction electrode 48, a deceleration electrode 50, and a ground electrode 52. 46 extracts the ion beam 20, and the shape of this extraction electrode system 46 may be as described above.

Further, although the above description has been made using an ion beam etching apparatus as an example, the present invention is not limited thereto, but is applicable to a batch-type apparatus that rotates and translates a disk, and is capable of using an ion beam etching apparatus as exemplified at the beginning. It can be widely applied to processing equipment.

〔Effect of the invention〕

As described above, according to the present invention, high beam utilization efficiency can be obtained even when the beam shape is enlarged.

In addition, throughput is also improved accordingly.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing the area around a disk of an ion beam etching apparatus according to an embodiment of the present invention. FIG. 2 is a schematic plan view showing an example of the electrode shape of the ion source according to the present invention. FIG. 3 is a schematic cross-sectional view showing another example of the ion source according to the present invention. FIG. 4 is a schematic cross-sectional view showing an example of a conventional batch type ion beam etching apparatus. 5 is a schematic plan view showing the area around the disk of the apparatus shown in FIG. 4. FIG.

Claims (1)

[Claims] (1) In an ion processing device that processes multiple samples mounted on the same radius of a disk that is rotated and translated in a vacuum from an ion source with an ion beam, the ion beam extraction of the ion source is performed. An ion processing device characterized in that at least the ion beam extraction portion of the electrode related to the above has an arcuate planar shape.