JPH02251143A - Ion beam sputtering equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ion beam sputtering apparatus for forming a thin film such as an insulating film or a metal film on a workpiece such as a semiconductor wafer.

[Conventional technology]

Conventional ion beam sputtering equipment, for example,
"Handbook of thin film production and evaluation and its application technology" (
The structure is as shown in P. 289 of Fuji, Techno System) or P. 121 of ``Thin Film Technology'' (Kyoritsu Shuppan).

FIG. 5 schematically shows an ion beam sputtering apparatus that can simultaneously process a plurality of workpieces such as semiconductor wafers. In the illustrated sputtering apparatus, a work holder 2 holding a plurality of works 1 such as semiconductor wafers rotates within a vacuum chamber 3 . On the other hand, a target 5 made of a sputtering material is held in a target holder (not shown) and placed in the vacuum chamber 3 apart from the workpiece 1 . An ion generation chamber 6 communicating with the vacuum chamber 3 is arranged above the target 5 . In the ion generation chamber 6, an inert gas such as Ar is ionized, and the generated ions are accelerated into a beam and collided with the target 5. At this time, sputtered particles ejected from the target 5 are attached to the surface of the workpiece 1, and the workpiece A thin film made of the same material as the target 5 can be formed on one surface.

A shutter 7 is interposed between the workpiece 1 and the target 5 from the start of the apparatus until the sputtering state becomes stable, and the shutter 7 captures sputtered particles flying out from the target 5 and heading towards the workpiece holder 2. During this time, the sputtered particles are prevented from adhering to the workpiece 1 (bliss sputtering).

[Problem to be solved by the invention]

By the way, in the manufacturing process of VLSIs, etc., the size of manufactured elements is being reduced, and along with this size reduction, insulating films formed on the surfaces of semiconductor wafers are becoming even thinner. . As described above, as films become thinner, it becomes necessary to form thin films accurately and uniformly to a desired thickness.

However, in the conventional ion beam type sputtering apparatus, when the shutter 7 is retracted from between the workpiece 1 and the target 5 while the workholder 2 is rotated, and sputtering is performed with the shutter 7 fully open, the workpiece holder 2 Since the rotational speed is high near the outer periphery of the workpiece, the workpiece passes through the flying area where sputtered particles fly in a short time, and the amount of sputtered particles deposited on the workpiece surface is maintained at the outer periphery of the workpiece holder 2. The portion held at the inner periphery is smaller than the portion held at the inner periphery. Therefore, the thickness of the formed film is also thinner in the portion held on the outer periphery than on the portion held on the inner periphery of the work holder 2, resulting in non-uniform film thickness. In order to avoid this, it is conceivable to employ a mechanism for rotating the work in the work holder, but this is not preferable because it complicates the mechanism, increases the manufacturing cost of the device, and makes it difficult to cool the work.

In addition, the range of sputtered particle deposition rates that can be achieved includes:
There is a limit, and the film thickness formed by passing through the flying area - times is determined from this deposition rate and the time required for the workpiece to pass through the flying area.

Therefore, when the deposition rate is very high, it is difficult to control the thickness of the formed film.

Therefore, in view of the above-mentioned circumstances, the present invention makes it possible to make the thin film formed on the workpiece uniform without complicating the structure of the workpiece holding means that holds the workpiece, and moreover,
It is an object of the present invention to provide an ion beam sputtering apparatus that allows easy control of the thickness of a formed film.

[Means to solve the problem]

In order to achieve the above object, in the ion beam sputtering apparatus according to the present invention, two shutter plates are provided between the workpiece holding means and the target holding means, closer to the rotation center axis of the workpiece holding means than the target. Each is pivotably supported around a positioned fulcrum, and furthermore, two
The present invention is characterized in that each of the shutter plates is formed with an end face roughly along the radial direction with respect to the central axis of rotation of the workpiece holding means, and these end faces are opposed to each other.

[Effect]

With this configuration, it is possible to make the area where sputtered particles fly toward the workpiece holding means wider at the outer circumference around the rotation center axis of the workpiece holding means and narrower at the inner circumference. The time required for the workpiece to pass through the flying area is approximately equal between the portion of the workpiece located on the outer circumference of the workpiece holding means and the portion of the workpiece located on the inner circumference of the workpiece holding means.

〔Example〕

Embodiments of the present invention will be described below with reference to Figures 1 to 4.

FIG. 1 is a perspective view schematically showing an apparatus according to an embodiment of the present invention.

As shown in the figure, in this embodiment, a work holder 12 is provided on the right side of a vacuum chamber 13 to hold a work 11 such as a semiconductor wafer by vacuum suction or the like. The work holder 12 is rotatably provided, and holds a plurality of works 11 on the circumference around the rotation center axis 18. Further, on the left side of the vacuum chamber 13, a target 15 made of a sputtering mill is held by a target holder (not shown). An ion generation chamber 25 communicating with the vacuum chamber 13 is arranged above the target 15 . Ion generation chamber 2
In step 5, an inert gas such as Ar is ionized by hot cathode electron bombardment or electron cyclotron resonance (ECR), and the generated ions are accelerated into a beam to reach the target 15.
It is designed to cause sputtering by causing the particles to collide with each other.

Therefore, the target 15 is separated from the workpiece 11, and the sputtered particles that fly out are placed on the workpiece holder 12.
It is held tilted at an appropriate angle toward the side.

Between the target 15 and the work 11 held by the work holder 12, the shape and size of the flying area on the work holder 12 side where the sputtered particles flying out from the target 15 fly are adjusted, and Control means 2 for controlling the amount of flying sputter particles in the radial direction with respect to the rotation center axis 18 of the work holder 12
0 is set. As shown in FIG. 2, the control means 20 includes two shutter plates 21 each having an end surface 21a formed along the radial direction with respect to the rotation center axis 18 of the work holder 12. There is. The two shutter plates 2] are each supported by an arm 22 with their end surfaces 21a facing each other. The arm 22 is pivotally supported near the rotation center axis 18 of the work holder 12 so as to be freely swingable.

Therefore, the shutter plate 21 swings together with the arm 22 about a fulcrum 23 near the rotation center axis 18 of the work holder 12.

FIG. 3 shows the arrangement relationship of the work 11, work holder 12, target 15, target holder 16, and shutter plate 21 when viewed from the direction of the rotation center axis 18 of the work holder 12.

As shown in this figure, a fan-shaped space is formed between the shutter plates 21, and this space is positioned and fixed above the target 15. In this state, the ion beam is emitted from the ion generation chamber 25 toward the target 15,
When sputtering is performed, sputtered particles flying out from the portion of the target 15 covered by the shutter plate 21 in FIG. 3 are captured by the shutter plate 21. Therefore, it is only the sputtered particles that have passed between the shutter plates 2 without being captured by the shutter plate 2 that fly out from the target 15 and reach the work holder 12. As a result, the sputtered particles on the surface of the work holder 12 The shape and size of the flying area where the flying object flies are as shown by hatching in FIG. 1, for example.

The shape of this flying area is approximately fan-shaped around the rotation center axis 18 of the work holder 12, although the outer and inner circumferential sides of the work holder 12 bulge out in an elliptical shape. In this way, by making the flying area on the work holder side fan-shaped, the work holder of the work 11 is
The time required for the portion located on the outer periphery of the work holder 12 to pass through the flying area is equal to the time required for the portion located on the inner periphery of the work holder 12 to pass through the flying area. Therefore, the amount of sputtered particles deposited on the work holder 12
The thickness of the film formed on the surface of the workpiece by sputtering is also made uniform.

Furthermore, in the above-described embodiment, if the distance between the shutter plates 21 is increased, the flying area on the work holder 12 side can be expanded, and if the distance between the shutter plates 21 is shortened, the flying area on the work holder 12 side can be expanded. Can be reduced. Moreover, even if the distance between the shutter plates 21 is adjusted in this manner, the amount of deposited sputtered particles is kept uniform on the outer circumferential side and the inner circumferential side of the work holder 12. Therefore, by adjusting the size of the flying area in this manner, the thickness of the film formed on the workpiece 11 while the workpiece 11 passes through the flying area once can be easily adjusted. Therefore,
By narrowing the distance between the shutter plates 21 and reducing the size of this flying area, it is theoretically possible to make the film thickness formed by passing through the flying area infinitely thinner, and the final film thickness can be made infinitely thinner. It becomes easy to precisely match the thickness of the thin film obtained as a target to the target thickness.

Incidentally, if the mutual spacing between the shutter plates 21 described above is eliminated, it is also possible to use this as a shutter for use in bliss sputtering in the same way as the conventional sputtering apparatus.

By the way, in the embodiment described above, the target 15
does not take into account the size and shape of In reality, the target 15 is usually circular and has a finite size. Further, the target 15 is fixed at a predetermined inclination angle with respect to the workpiece. Therefore, in reality, as shown in FIGS. 1 to 3, the shutter plate 2
If the opposing end surfaces 21a of 1 are formed in a straight line,
The film thickness tends to be thicker in the portion facing the center portion of target] 5. Furthermore, there is a structural limit to the position of the pivot point 23 of the arm 22 that supports the shutter plate 2. Therefore, in such a case, as shown in FIG.
between the rotation center axis of the target 15 and the target 15.
Place it closer to 5. Here, the illustrated end surface 21.a of the shutter plate 21 is curved out in an almost circular arc shape. It is sufficient that a is formed approximately along the radial direction with respect to the rotation center axis 18, and may be formed of a plurality of flat surfaces connected to each other at an obtuse angle.

Note that the shape of the end surface 21a of the shutter plate 21 and the position of its pivot point 23 may be optimized depending on the diameter of the target, the effective sputtering area, and the arrangement relationship between the workpiece, the shutter plate, and the target. preferable.

Further, in the embodiment described above, a single target 1
5 is shown only as being held in the vacuum chamber 13, but the ion beam sputtering apparatus according to the present invention is not limited to this, and a plurality of targets made of different sputtering materials can be held in the vacuum chamber. Hold it, Targera!・The above-mentioned control means 20 may be provided for each.

Furthermore, the two shutter plates 2 described above have a substantially half-moon shape consisting of an end surface 21a formed substantially radially with respect to the rotation center axis 18 of the work holder 12 and an outer circumferential surface formed in an arc shape. However, the outer peripheral surface may be formed into a polygonal shape.

〔Effect of the invention〕

As explained above, in the ion beam sputtering apparatus according to the present invention, the thickness of the thin film formed on the workpiece can be made uniform, and the desired film thickness can be obtained accurately and easily. . Furthermore, there is no need to provide the workpiece holding means with a mechanism for rotating the workpiece, and the present invention can be realized with a simple configuration. Therefore, it becomes possible to increase the degree of integration of VLSIs and the like, and it also becomes possible to provide highly reliable semiconductor devices at low cost.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing an embodiment of an ion beam sputtering apparatus according to the present invention, FIG. 2 is a perspective view of the control means shown in FIG. 1, and FIG. 3 is a perspective view of the control means shown in FIG. 1. FIG. 4 is a side view showing the arrangement of the main parts of an ion beam sputtering device, FIG. 4 is a perspective view showing control means different from the control means shown in FIG. 2, and FIG. 5 is a conventional example of an ion beam sputtering device. FIG. 2 is a schematic perspective view. 11... Work, 12... Work holder 13...
Vacuum chamber 15...Target, 16...Target holder 18...Rotation center axis, 20...
Control means, 21... shutter plate, 21. a... End face, 22... Arm, 25... Ion generation chamber. Control means diagram Layout of shutter plate etc. Control means Figure 4 Conventional example Figure 5

Claims (1)

[Claims] Without rotating a workpiece on which a thin film is formed,
A workpiece holding means that holds and rotates a plurality of workpieces in a circumferential direction around a central axis of rotation, and ions that collide an ion beam with a target made of a sputtered material that forms the thin film to cause sputtered particles to fly out toward the workpiece holding means side. An ion beam sputtering apparatus comprising a beam generating means, wherein the work holding means and the target holding means are each swingable about a fulcrum located closer to the rotation center axis than the target. the control means for controlling the amount of sputtered particles flying from the target toward the workpiece holding means in the radial direction with respect to the rotation center axis; An ion beam sputtering apparatus characterized in that each of the shutter plates has end surfaces formed approximately along a radial direction with respect to the rotation center axis of the work holding means, and the end surfaces are opposed to each other.