JPH0727767B2 - Ion processing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention treats a sample mounted on a disk that is rotated and translated in vacuum by irradiating a planar ion beam without scanning the sample. The present invention relates to an ion treatment apparatus, and more particularly to improvement of an electrode shape of an ion source of the apparatus.

[Conventional technology]

The ion processing apparatus includes an ion implantation apparatus, an ion deposition thin film forming apparatus that uses both ion implantation and vacuum deposition, an ion beam etching apparatus, and the like. An ion beam etching apparatus will be described below as an example.

FIG. 4 is a schematic sectional view showing an example of a conventional batch type ion beam etching apparatus. Inside the vacuum container 26, there is provided a disk 22 which is rotated by a disk rotation / translation mechanism 28, for example, as indicated by arrow A and translated as indicated by arrow B, and the same radius R ₁ (of the surface of the disk 22 R ₁ ( A plurality of wafers (samples) 24 are mounted on the wafer (see FIG. 5). Then, a planar ion beam 20 is extracted from the ion source 2 to each wafer 24 and is irradiated without scanning, so that the wafer 24 is processed, for example, etched in this example.

The ion source 2 is an ECR type ion source in this example, and a plasma chamber 8 for producing plasma, a gas supply source 12 for supplying an active gas, for example, to the plasma chamber 8 and microwave power are supplied to the plasma chamber 8 through a waveguide 6. The microwave oscillator 4, the magnetic field coil 10 for confining the plasma, and the extraction electrode system 14 for extracting the ion beam 20 from the plasma chamber 8 are provided. The extraction electrode system 14 is, in this example, an ion beam.
20 An extraction electrode (also referred to as an acceleration electrode or a plasma electrode, hereinafter the same) 16 for extraction and a deceleration electrode 18 that repels electrons from the downstream side.

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

v∝I / R where I 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.

FIG. 5 is a schematic plan view showing the periphery of the disk of the apparatus shown in FIG. Each wafer 24 on the disk 22, which is rotated as indicated by arrow A, sequentially passes through the irradiation region of the ion beam 20, and the ion beam 20 is relatively scanned by the translation of the disk 22 as indicated by arrow B. Scan width SW in that case
₁ is determined by the distance to where the ion beam 20 does not hit the wafer 24 when scanned. The ion beam 20 and the extraction electrode system 14 of the ion source 2 have substantially the same shape and are substantially at the same position in a plan view.

[Problems to be solved by the invention]

Extraction electrode system 14 of the ion source 2 in the device as described above
For example, a square or a rectangle is conventionally used as the plane shape of the electrode. In such a case, if the electrode area is increased and the beam amount is increased, the lateral width or the vertical length of the electrode is increased. Need to let.

However, when the lateral width of the electrode, that is, the width W ₁ of the ion beam 20 is increased, the scanning width SW ₁ is significantly increased accordingly. Further, when the length of the electrode, that is, the length L ₁ of the ion beam 20 is increased to be larger than the diameter of the wafer 24 as shown in FIG. 5, the ion beam 20 does not hit the adjacent wafer 24. Since the beam 20 has to be relatively scanned, the scanning width SW ₁ also becomes large in this case.

Therefore, in either case, the beam utilization efficiency (= total area of the wafer / total irradiation area of the ion beam) is reduced due to the increase of the scanning width SW ₁ .

Therefore, an object of the present invention is to provide an ion processing apparatus which can obtain a large beam utilization efficiency even when the beam shape is enlarged.

[Means for Solving the Problems] In the ion processing apparatus of the present invention, at least the ion beam extraction portion of the electrode related to the extraction of the ion beam of the ion source has a plane shape in a direction substantially along the envelope of the wafer row on the disk. It is characterized by having a curved arc shape.

[Action]

Since the planar shape of at least the ion beam extraction portion of the electrode of the ion source is an arc shape curved in a direction substantially along the envelope of the wafer array on the disk, the ion beam also has a planar shape of the envelope array of the wafer array on the disk. An arcuate shape is obtained which is bent in a direction substantially along the. Therefore, even when the beam shape is increased, the width for translating the disk,
That is, the relative scanning width of the ion beam can be reduced, and as a result, a large beam utilization efficiency can be obtained.

〔Example〕

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

In this embodiment, the electrodes relating to the extraction of the ion beam 20 of the ion source 2, that is, the extraction electrode 16 of the extraction electrode system 14 and at least the ion beam extraction portion of the deceleration electrode 18 in this example have a planar shape of the disk 22. As shown in the drawing, the shape of the ion beam 20 extracted from the arc shape curved in a direction substantially along the envelope 241 or 242 of the upper wafer row is also as shown in the figure. It has an arc shape that is bent in a direction substantially along.

More specifically, as shown in FIG. 2, the planar shape of the extraction electrode 16 has a substantially constant width W ₂ and the inside arc
161 radius R ₂ and both the wafer radius R ₃ of the outer arc 162 of
The radius R ₁ of the disk 24 to the center of the disk 22 is almost equal (that is, R ₁ ≈R ₂ ≈R ₃ ), and its length L ₂ is larger than the diameter of the wafer 24. A small hole 163 for extracting the ion beam 20 is provided on one surface 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 above electrode shape,
As shown in FIG. 1, an arc-shaped ion beam 20 having a width of about W ₂ and a length of about L ₂ is extracted, and this is irradiated onto a wafer 24 on a disk 22. In this case, the ion beam 20
The inner arc 201 and outer arc 202 of the
Since the shape is substantially along the envelope 242 connecting the outside and the envelope 241 connecting the inside, the relative scanning width of the ion beam 20
SW ₂ can be made smaller than the scanning width SW ₁ in the conventional case, whereby a large beam utilization efficiency can be obtained even when the shape of the ion beam 20 is enlarged as shown in the figure.

For example, the width W ₁ = W ₂ = 80 mm of the ion beam 20, the length L ₁ = L ₂
= 300 mm, radius of wafer row R ₁ = 345 mm, radius of wafer 24 r
= 75 mm and the number of wafers 24 is 13, the beam utilization efficiency has been improved from about 40% in the conventional case (FIG. 5) to about 45% in this embodiment. Moreover, such an improvement in beam utilization efficiency leads to an improvement in throughput (the number of processed wafers per unit time) in processing (for example, etching) the wafer 24.

Further, the radius R ₃ of the radius R ₂ and the outer arc 162 of the inner arc 161 of the extraction electrode 16 through the deceleration electrode 18, its respective radius _{R 5 (= R 1 + r} ) of the outer envelope 242 as described above and It may be approximately equal to the radius R ₄ (= R ₁ −r) of the inner envelope 241 (ie R ₂ ≈R ₅ , R ₃ ≈R ₄ ) and then the inner arc of the ion beam 20. 201 and outer arc 202 are now substantially completely along envelopes 242 and 241, respectively,
This allows the scan width SW ₂ to be minimized.

The type of the ion source 2 and the number of electrodes for extracting the ion beam 20 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 bucket type ion source, which performs plasma generation and confinement by the arc chamber 40, the filament 42, the magnet 44, etc., and the extraction electrode 48,
The extraction electrode system 46 including the deceleration electrode 50 and the ground electrode 52 extracts the ion beam 20, and the extraction electrode system 46 may be shaped as described above.

Further, although the ion beam etching apparatus has been described above as an example, the present invention is not limited thereto, and it is a batch type for rotating and translating the disk, and the ion as illustrated at the beginning. It can be widely applied to processing devices.

〔The invention's effect〕

As described above, according to the present invention, it is possible to extract an arc-shaped ion beam, which is planar and curved in a direction substantially along the envelope of the wafer array on the disk, from the ion source, thus increasing the beam shape. Even in such a case, a large beam utilization efficiency can be obtained. In addition, the throughput is also improved accordingly.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing the periphery of 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 sectional view showing another example of the ion source according to the present invention. FIG. 4 is a schematic sectional view showing an example of a conventional batch type ion beam etching apparatus. FIG. 5 is a schematic plan view showing the periphery of the disk of the apparatus shown in FIG. 2 ... Ion source, 14 ... Extraction electrode system, 16 ... Extraction electrode, 18 ... Deceleration electrode, 20 ... Ion beam, 22 ... Disk, 24 ... Wafer (sample), 46 ... Extraction electrode system

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 21/3065

Claims (1)

[Claims] 1. A plurality of samples mounted on the same radius of a disk that is rotated and translated in a vacuum are irradiated with a planar ion beam extracted from the ion source and not scanned, and the sample is irradiated. In the ion treatment device for treating
An ion processing apparatus, wherein at least an ion beam extraction portion of an electrode related to extraction of an ion beam of an ion source is formed into an arc shape which is curved in a direction substantially along an envelope of a wafer row on a disk.