JP2008124281A - Dry etching apparatus and dry etching method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable simultaneous etching of a plurality of objects to be processed, and enable uniform in-plane etching of each object to be processed. <P>SOLUTION: The dry etching apparatus comprises: a charged particle generating unit (ion source chamber 10) for irradiating charged particles; a rotation stage 30 for supporting and rotating a plurality of objects to be processed (processing board 100) that are irradiated with charged particles; and a shield plate 40, provided between the charged particle generating unit and the rotation stage, for shielding the charged particles irradiated from the charged particle generating unit, wherein the amount of in-plane irradiation from the charged particle generating unit to the objects to be processed is adjusted by turning the shield plate to adjust the amount of projection of the shield plate 40 relative to the charged particles. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a dry etching apparatus and a dry etching method that improve the in-plane uniformity of the etching distribution of an object to be processed.

  As an apparatus for etching the surface of a semiconductor substrate or a glass substrate for a liquid crystal display according to a predetermined pattern, a dry etching apparatus such as ion milling or reactive ion etching (RIE) is known. In these dry etching apparatuses, the in-plane uniformity of the etching distribution of the semiconductor substrate is determined by the positional relationship between the distribution state of charged particles such as reactive ions and plasma and the semiconductor substrate.

  In manufacturing a device such as a semiconductor integrated circuit or a micromachine by thin film microfabrication, since a large number of elements are manufactured in one semiconductor substrate, the in-plane uniformity of the etching distribution of the semiconductor substrate is important. This is because, if the in-plane uniformity of the etching distribution of the semiconductor substrate is poor, there is a risk of variations in characteristics between elements, which may cause quality degradation.

  As a system for improving the in-plane uniformity of the etching distribution, an ion beam processing apparatus has been proposed in which a plasma extraction electrode is provided in the vacuum processing chamber and the plasma energy distribution in the vacuum processing chamber is controlled using the plasma extraction electrode. (See Patent Document 1).

  On the other hand, by providing a shielding plate between the ion beam source and the processing substrate processed thereby, the ion beam dose is reduced uniformly, thereby preventing an increase in the temperature of the processing substrate due to the collision of the ion beam. An irradiation apparatus has been proposed (see Patent Document 2).

JP 2002-216653 A JP-A-9-162142

  However, the former ion beam processing apparatus has a problem that the apparatus itself becomes large and complicated.

  In the latter ion beam irradiation apparatus, the temperature of each processing substrate is provided by intermittently irradiating the processing substrate with a shielding plate provided between the ion beam source and the processing substrate processed thereby. Although the rise can be prevented, there is a problem that the irradiation amount of the ion beam irradiated to each processing substrate cannot be controlled, and the in-plane uniformity of the etching distribution of each processing substrate cannot be improved. It was. Also, this ion beam irradiation apparatus is inefficient because there is always only one processing substrate irradiated with the ion beam, and most of the ion beam irradiated from the ion beam source is shielded by the shielding plate. And a problem that a plurality of processing substrates cannot be processed simultaneously.

  In view of the circumstances described above, the present invention provides a dry etching apparatus and a dry etching method capable of simultaneously etching a plurality of objects to be processed and uniformly etching the surface of each object to be processed. With the goal.

An aspect of the present invention includes a charged particle generation unit that irradiates charged particles, a rotation stage that supports and rotates a plurality of objects to be irradiated with the charged particles, and the charged particle generation unit and the rotation stage. A shielding plate that is provided in between and shields the charged particles irradiated from the charged particle generation unit, and rotates the shielding plate to project the shielding plate formed on the workpiece. In the dry etching apparatus, the amount of charged particles irradiated to the object to be processed from the charged particle generation unit is adjusted by adjusting the size.
In this aspect, the in-plane irradiation amount of the charged particles irradiated from the charged particle generator to the object to be processed can be adjusted by adjusting the projection size of the shielding plate formed on the object to be processed. As a result, a plurality of objects to be processed can be etched at the same time, and the surface of each object to be processed can be uniformly etched.

Here, it is preferable that the shielding plate is supported at the base end portion, and a wide portion is formed at the tip end portion, and it is rotated around an axis from the base end portion toward the tip end portion.
According to this, a predetermined part of charged particles irradiated from the charged particle generating unit can be shielded, so that the amount of charged particles irradiated to the object to be processed from the charged particle generating unit can be reduced. More accurate control is possible.

Moreover, it is preferable that the said rotation stage has a to-be-processed object rotation means to rotate each to-be-processed object.
According to this, since the irradiation amount of the ion beam irradiated to each processing object can be made more uniform, the in-plane of each processing object can be etched more uniformly.

Moreover, it is preferable that the charged particle generator and the rotary stage are provided on the rotary stage side from the midpoint.
According to this, it is possible to more accurately control the irradiation amount of the ion beam irradiated to the object to be processed.

According to another aspect of the present invention, the charged particle is provided between a charged particle generation unit that irradiates charged particles and a rotary stage that mounts and rotates a plurality of objects to be irradiated with the charged particles. By rotating a shielding plate that shields the charged particles irradiated from the generation unit, and adjusting the size of the projection of the shielding plate formed on the object to be processed, the charged particle generation unit can remove the charged particles from the charged particle generation unit. The dry etching method is characterized by adjusting an in-plane irradiation amount of charged particles irradiated to a processing object.
In this aspect, the in-plane irradiation amount of the charged particles irradiated from the charged particle generator to the object to be processed can be adjusted by adjusting the projection size of the shielding plate formed on the object to be processed. As a result, a plurality of objects to be processed can be etched at the same time, and the surface of each object to be processed can be uniformly etched.

Hereinafter, the best mode for carrying out the present invention will be described. The description of the present embodiment is an exemplification, and the present invention is not limited to the following description.
(Embodiment 1)
FIG. 1 is a schematic view showing an ion milling apparatus as an example of a dry etching apparatus according to Embodiment 1 of the present invention, FIG. 2 is an enlarged schematic view of a rotary stage of this embodiment, and FIG. 3 is this embodiment. It is an enlarged schematic diagram of the shielding plate and shielding plate control means.

  As shown in FIG. 1, an ion milling apparatus 1 according to this embodiment includes an ion source chamber 10 that is a charged particle generation unit that irradiates an ion beam, and an ion that mills a processing substrate 100 that is an object to be processed by the ion beam. And a milling chamber 20.

  The ion source chamber 10 is connected to the ion milling processing chamber 20 in the horizontal direction so that the ion milling processing chamber 20 is arranged on the left side, and constitutes a vacuum chamber together with the ion milling processing chamber 20. Exhaust systems (such as a rotary pump and a turbo molecular pump or a claion pump) 16 and 26 are connected to the lower part of the ion source chamber 10 and the lower part of the ion milling treatment chamber 20, respectively. The gas inside is evacuated. Further, a gas introduction pipe 15 into which an inert gas such as Ar gas is introduced is connected to the right side wall of the ion source chamber 10, and the inert gas is introduced into the ion source chamber 10.

  The ion source chamber 10 has a filament 11 and an electrode 12. The filament 11 is disposed on the right side wall of the ion source chamber 10, and an inert gas such as Ar gas introduced through the gas introduction pipe 15 is ionized by supplying current to the filament 11 and heating it. Thus, Ar ions are generated.

  The electrode 12 is provided on the left side of the ion source chamber 10 so as to face the filament 11 and constitutes a part of the ion source chamber 10. A large number of holes are formed in the electrode 12, and by applying a negative potential to the electrode 12, Ar ions are accelerated and Ar ions are drawn from each hole to the ion milling processing chamber 20 and are horizontally formed as an ion beam. It can be irradiated in the direction.

  The ion milling processing chamber 20 has a rotary stage 30 and a shielding plate 40. The rotary stage 30 is arranged on the left side wall of the ion milling processing chamber 20 via a cylindrical stage holder 34, and a rotary means 31 such as a motor for rotating the rotary stage 30 in the direction of the rotation axis of the stage holder 34, and a rotary stage 2 has a processing object rotating means (processing substrate rotating means 32) such as a motor for rotating (spinning) the processing substrate 100 supported by the rotating stage 30 in the same direction as the rotation direction of the rotary stage 30, as shown in FIG. As described above, the plurality of processing substrates 100 are supported and rotated, and each processing substrate 100 itself can be rotated. That is, the rotation stage 30 can rotate while supporting each processing substrate 100 that rotates. Further, the rotary stage 30 further has a movable portion 33, and the angle of the rotary stage 30 with respect to the ion beam can be adjusted. That is, by adjusting the movable portion 33, the ion beam can be irradiated to the processing substrate 100 supported by the rotary stage 30 at a predetermined angle. In addition, the rotation direction of the rotation stage 30 and the rotation direction of the processing substrate 100 are not particularly limited, and they may all rotate in the same direction, or the rotation direction of the rotation stage 30 and the processing substrate 100 may be opposite. It may be rotating.

  As shown in FIGS. 1 and 3, the shielding plate 40 is provided between the ion source chamber 10 and the rotary stage 30, and is arranged at the center in the width direction of the ion milling processing chamber 20 (not shown). The distal end portion 41 which is the wide portion of the shielding plate 40 is formed in an elliptical shape, and the proximal end of the shielding plate 40 penetrates the lower wall of the ion milling processing chamber 20 and is connected and supported by the shielding plate driving means 45. Yes. The shielding plate driving means 45 has a driving source such as a motor (not shown), and can rotate the shielding plate 40 about the axis (R direction) from the base end portion toward the tip end portion, and in the ion milling chamber. The length L from the lower wall 20 to the tip of the shielding plate 40 can be changed. That is, the angle of the shielding plate 40 with respect to the ion beam can be changed by the shielding plate driving means 45, and the position of the tip portion 41 can be moved in the vertical direction. The shielding plate 40 is not particularly limited as long as it is made of a material that is not etched by an ion beam, and examples thereof include a plate made of titanium. The shielding plate 40 may be provided anywhere between the ion source chamber 10 and the rotary stage 30, but is closer to the rotary stage 30 than the midpoint between the ion source chamber 10 and the rotary stage 30. It is preferable to provide it. By providing the shielding plate 40 at a position closer to the rotary stage 30 than the midpoint between the ion source chamber 10 and the rotary stage 30, the irradiation amount of the ion beam applied to the processing substrate 100 can be controlled more accurately. It is.

  Here, since the shielding plate 40 is disposed between the ion source chamber 10 and the rotary stage 30 as described above, the shielding plate 40 is a part of the ion beam irradiated to the processing substrate 100 from the ion source chamber 10. Will be shielded. As shown in FIG. 4, the amount of the ion beam shielded by the shielding plate 40 is proportional to the projection of the shielding plate 40 on the ion beam (S · cos θ: S is the area of the shielding plate). By rotating the plate 40 and changing the projection size of the shielding plate 40 formed on the processing substrate 100, the amount of the ion beam irradiated to the processing substrate 100 can be adjusted. Since each processing substrate 100 is rotated by the rotary stage 30 as described above, when the processing substrate 100 is positioned in the projection of the shielding plate 40 on the ion beam, the ion substrate is irradiated with the ion beam. However, if it is located outside the projection, the ion beam is irradiated onto the processing substrate 100. That is, as the rotary stage 30 rotates, each processing substrate 100 alternately passes through the region irradiated with the ion beam and the region not irradiated with the ion beam. As a result, the time for which each processing substrate 100 is irradiated with the ion beam changes according to the projection size of the shielding plate 40, and as a result, the irradiation amount of the ion beam irradiated to the processing substrate 100 changes. . Therefore, even if there is a partial variation in the ion density of the ion beam irradiated from the ion source chamber 10, the tip portion 41 of the shielding plate 40 is disposed at a position corresponding to a portion where the ion density of the ion beam is high. At the same time, by rotating the shielding plate 40 to adjust the projection size of the shielding plate 40, the in-plane irradiation amount of the ion beam irradiated onto the processing substrate 100 can be made uniform. The processing substrate 100 can be etched at the same time, and the surface of each processing substrate 100 can be uniformly etched. Further, in this embodiment, since the processing substrate 100 itself is further rotated, the in-plane irradiation amount of the ion beam irradiated to each processing substrate 100 can be made more uniform, and the in-plane of each processing substrate 100 can be made uniform. Can be etched more uniformly.

  The shielding plate 40 is preferably arranged so that the irradiation amount of the ion beam irradiated from the central portion of the ion source chamber 10 can be controlled. Since the ion density of the ion beam irradiated from the central portion of the ion source chamber 10 tends to be higher than that irradiated from other portions, the irradiation amount of the ion beam irradiated from the central portion of the ion source chamber 10 This is because the in-plane irradiation amount of the ion beam irradiated onto the processing substrate 100 can be made more uniform by arranging the shielding plate so as to control the above.

  Next, operation | movement of the ion milling apparatus 1 which concerns on this embodiment is demonstrated. First, after each processing substrate 100 is set on the rotary stage 30, the ion milling chamber 20 is decompressed to a predetermined vacuum state by the exhaust system 26, and the ion source chamber 10 is decompressed to a predetermined vacuum state by the exhaust system 16. Is done. Next, Ar gas is introduced into the ion source chamber 10. When a current is passed through the filament 11 provided in the ion source chamber 10, the Ar gas is ionized and Ar ions are generated. Next, when a negative potential is applied to the electrode 12, Ar ions are accelerated in the direction of the electrode 12 and irradiated into the ion milling processing chamber 20 as an ion beam.

  The ion beam irradiated into the ion milling processing chamber 20 is irradiated to each processing substrate 100 supported by the rotary stage 30, and milling is performed. At this time, as described above, for example, among the ion beams irradiated from the ion source chamber 10, the front end portion 41 of the shielding plate 40 is disposed at a position corresponding to a portion where the ion density of the ion beam is high, and the shielding plate 40. Is rotated to adjust the projection size of the shielding plate 40 with respect to the ion beam to uniformize the irradiation amount of the ion beam, so that a plurality of processing substrates 100 can be etched simultaneously, and each processing substrate can be etched. In-plane 100 can be etched uniformly.

(Other embodiments)
In Embodiment 1, the shielding plate 40 in which the tip portion 41 is formed in an elliptical shape is used as the shielding plate 40, but the shape of the shielding plate 40 is not particularly limited. As the shielding plate 40, a plate whose tip is formed in a rectangular shape or a plate in which a mesh is formed at the center of the tip formed in an elliptical shape may be used.

  In the first embodiment, the ion milling apparatus has been described as an example of the dry etching apparatus. However, the present invention is widely applicable to all dry etching apparatuses, and of course, the dry etching apparatus other than the ion milling apparatus can be used. Can be applied. Other dry etching apparatuses are not limited as long as they are apparatuses that process materials with reactive gases, ions, and radicals. For example, reactive ion etching (RIE) and substrate processing in vacuum such as ion irradiation are performed. Examples thereof include devices.

  Furthermore, in the first embodiment, the processing in the same state from the start to the end of etching processing in which the in-plane of the plurality of processing substrates 100 is uniformly etched has been described. However, the present invention is also applicable to processing in an intermediate stage. Can do. For example, the present invention can also be applied to processing in which the in-plane etching distribution of the workpiece is variable in accordance with the processing sequence.

  Moreover, you may give a negative electric potential to the shielding board 40 of Embodiment 1. FIG. By controlling the potential applied to the shielding plate 40, the ion beam irradiated to each processing substrate 100 can be controlled, and the in-plane irradiation amount of the ion beam irradiated to each processing substrate 100 can be made more uniform. .

<Example>
A large-diameter ion source having a diameter of 580 mm is used as the ion source chamber, a silicon wafer having a diameter of 150 mm is used as the processing substrate, and a titanium plate having an elliptical tip having a major axis of 250 mm and a minor axis of 30 mm is used as the shielding plate. The ion milling apparatus of Embodiment 1 was configured, and the processing substrate was milled using an ion beam (Ar ion beam) with relatively high ion density uniformity irradiated from the center of the ion source chamber.

<Comparative example>
The processing substrate was milled under the same conditions as in the example except that no shielding plate was present.

<Test results>
In the comparative example, the in-plane uniformity of the etching distribution of each processing substrate could not be improved within ± 3%, but in the example, the in-plane uniformity of the etching distribution of each processing substrate was within ± 1%. It was possible to improve. That is, by providing a shielding plate and adjusting the angle of the shielding plate with respect to the ion beam and the position of the tip of the shielding plate with respect to the ion source chamber, the in-plane uniformity of the etching distribution of each processing substrate can be improved. It was.

  Etching of each processing substrate with high reproducibility can be achieved by adjusting the shielding plate in the same way for changes in ion beam intensity distribution due to changes in process parameters such as ion acceleration voltage, beam current, and processing vacuum. It was found that the in-plane uniformity of distribution can be maintained.

1 is a schematic diagram of an ion milling apparatus according to Embodiment 1. FIG. FIG. 3 is an enlarged schematic view of a rotary stage according to the first embodiment. It is an expansion schematic of the shielding board and shielding board control means of Embodiment 1. 2 is a schematic top view of the shielding plate of Embodiment 1. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Ion milling apparatus, 10 Ion source chamber, 11 Filament, 12 Electrode, 15 Gas introduction pipe, 16, 26 Exhaust system, 20 Ion milling processing chamber, 30 Rotating stage, 31 Rotating means, 32 Processing substrate rotating means, 33 Movable part , 34 stage holder, 40 shielding plate, 41 tip, 45 shielding plate driving means, 100 processing substrate

Claims (5)

A charged particle generator that irradiates charged particles; a rotary stage that supports and rotates a plurality of objects to be irradiated with the charged particles; and is provided between the charged particle generator and the rotary stage. A shielding plate that shields the charged particles irradiated from the charged particle generating unit, and rotating the shielding plate to adjust the projection size of the shielding plate formed on the object to be processed. A dry etching apparatus characterized by adjusting an in-plane irradiation amount of charged particles irradiated to the object to be processed from the charged particle generation unit. The said shielding board is supported by the base end part, and the wide part is formed in the front-end | tip part, It rotates around the axis | shaft which goes to this front-end | tip part from this base end part. Dry etching equipment. The dry etching apparatus according to claim 1, wherein the rotation stage includes a processing object rotating unit that rotates each processing object. The dry etching apparatus according to claim 1, wherein the shielding plate is provided closer to the rotary stage than a middle point between the charged particle generator and the rotary stage. The charged particles emitted from the charged particle generator provided between a charged particle generator for irradiating charged particles and a rotating stage for rotating a plurality of workpieces irradiated with the charged particles. By rotating the shielding plate that shields the object, and adjusting the projection size of the shielding plate formed on the object to be processed, the charged particles emitted from the charged particle generator to the object to be processed A dry etching method characterized by adjusting an in-plane irradiation amount.

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