JPS5854191B2 - Double-sided sputtering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a sputtering apparatus for producing thin films having the same properties on both sides of a flat substrate.

In particular, the present invention relates to an apparatus that can form thin films on both surfaces of a substrate almost simultaneously by sputtering in order to prevent deformation of the substrate due to internal stress generated in a sputtered film attached to the substrate when the substrate is thin.

At the very early stage when a thin film is formed by sputtering, the crystal lattice spacing of the atoms forming the film is thought to be arranged close to the crystal lattice spacing of the atoms in the underlying substrate.

As the film grows and becomes thicker, the atomic arrangement approaches the original crystal lattice spacing of the material forming the film.

Therefore, the atomic arrangement within the film is not completely uniform, and this is the primary cause of stress within the film.

Next, during film fabrication by sputtering, high-energy argon atoms hit the substrate side, and some of them penetrate into the film.

Argon atoms, which should not exist in the first place, enter the interstitial spaces of the crystal lattice forming the film, exerting a force that tries to expand the lattice, which causes compressive stress within the film.

Further, if the substrate temperature during sputtering is not room temperature, stress will be generated in the film if the temperature is returned to room temperature after film fabrication because the film material and the substrate material have different coefficients of thermal expansion.

The above is thought to be the mechanism by which stress is generated in a film produced by sputtering.

The stresses that occur are in different directions: tensile and compressive.

Whether the stress is compressive or tensile is influenced not only by the combination of film and substrate materials, but also by the substrate temperature during film fabrication, film deposition rate, pressure during sputtering, and other fabrication conditions. .

When a large stress is applied to the membrane, whether compressive or tensile,
This causes distortion or deformation of the film or substrate.

Particularly when the substrate is relatively thin, the stress generated in the film causes the substrate to deform.

In the case of tensile stress, the membrane exerts a shrinking force on the substrate, so that the surface of the substrate with the membrane becomes concave.

Conversely, in the case of compressive stress, the film applies a force that expands the substrate at the interface with the substrate, so that the surface with the film becomes convex.

These deformations are undesirable in many applications.

It is effective to form a film on both sides of the substrate to prevent deformation.

As a result, stress is applied to the film, but the stress generated on both sides of the substrate compensates for each other as a whole, and deformation of the substrate can be avoided.

However, it is actually very difficult to form a film of a predetermined thickness on one side of the substrate and then form a film of the thickness necessary to correct the deformation on the opposite side of the substrate.

To achieve this, it is necessary to change the film formation conditions on both sides.

Even if deformation of the substrate can be prevented by such a method, since the film forming conditions on both sides are different, the properties of the films formed on both sides will be significantly different, and in some cases, they may become completely unusable.

The present invention aims to solve these problems by providing a technique and an apparatus for producing a film having substantially the same properties on both sides at the same time under substantially the same film production conditions.

The film production according to the present invention will be explained below with reference to the drawings.

In a conventional sputtering apparatus, as shown in FIG. 1, two electrodes 1, that is, targets are arranged in a sputtering chamber 2, above and below a substrate 3.

Although it is possible to sputter separately from two independent targets to create a layer on each side of the substrate, it is possible to create a layer of the same quality and thickness on both sides at exactly the same film deposition rate. That is very difficult.

Assembling two electrodes in such a shape tends to complicate the structure of the device.

Furthermore, the manufacturing cost of the device is high and operability and maintenance are low.

FIG. 2 is a sectional view of the double-sided sputtering apparatus of the present invention.

In the figure, 4 is an electrode or target, 5 is a substrate holder, 6 is a substrate, 7 is a substrate holder support shaft, 8 is a bearing shaft, 9 is a bearing, 10 is a bearing holder, 11 is a gear cover, and 12 is a holder Fixed base, 13 is a rotating ring, 14 is a large diameter bearing, 15
is the bearing holder, 16 is the bearing holder ring,
17 is a rail, 18 is a motor, 19 is a small gear, 20 is a large gear, 21 is a connecting shaft, 22 is a rotating base ring, 23 is a support ring, 24 is a nut plate, 25 is an L-shaped support plate, 26 is a support ring Fixed plate, 27 is a spring pin,
28 is a spring presser, 29 is a slide shutter, 30 is a rotary shutter, 31 is a small gear, and 32 is a gear dog.

In the apparatus of the present invention, all of these mechanical parts for double-sided sputtering are assembled based on the bearing holder ring 16, so the structure is such that the bearing holder 16 can be removed together.

Therefore, the planetary type board holder 33 in FIG.
It can be installed extremely easily.

The ability to perform sputtering on one or both sides with a single device makes it widely available.

Details of sputtering on both sides of the substrate will be explained.

As shown in FIG. 2, the target 4, rotary shutter 30, and slide shutter 29 are arranged vertically.

The rotating shutter 30 is used during preliminary sputtering before starting sputtering.

During the main sputtering, the slide shutter 29 is shifted to the right.

In order to hold the substrate 6, the substrate 6 is attached to a substrate holder 5, and the substrate holder 5 is fixed to a substrate holder support shaft 7.

Insert this into the bearing shaft 8.

The bearing shaft 8 is supported by a bearing 9 and is assembled into a bearing holder 10.

The bearing holder 10 is fixed to a rotating ring 13 by a holder fixing base 12.

A large-diameter bearing 14 is fitted into the rotating ring 13, and is also fitted into a bearing holder ring 16 placed on a rail 17.

A bearing holder 15 is attached to the bearing holder 1 to prevent film adhesion due to sputtering and to hold down the bearing.
It is fixed at 6.

This structure allows the small gear 31 meshing with the gear dog 32 to rotate.

Further, a gear cover 11 is attached to the rotating ring 13 to prevent sputtered film from adhering to the gear.

The small gear 31 is fixed to the bearing shaft 8 and is driven into the substrate holder support shaft 7.

Since the spring pin 27 is placed in the groove of the bearing shaft 8, the substrate holder 5 can be rotated.

In order to actually rotate and revolve the substrate holder 5, the motor 18 is driven, the small gear 19 of the drive shaft is rotated, and the large gear 20 is rotated.
A connecting shaft 21 fixed to the rotating base ring 22 enters the groove of the rotating base ring 22 and transmits rotation.

Note that this rotating base ring 22 includes a support ring 23.
is fixed, and the L-shaped support plate 25 connects it to the nut plate 2.
4, and a support ring fixing plate 26 connects and fixes these and the rotating ring 13.

Therefore, by rotating the motor 18, the rotating ring 13 rotates, the small gear 31 rotates, and the substrate holder 5 rotates while revolving.

In the above embodiment, the revolution speed is 12 rpm.

The rotation speed is 1100 rpm.

Furthermore, since it has such a mechanism that rotates while revolving, the thickness of the film created by sputtering becomes uniform.

Moreover, the internal stress generated in the sputtered film attached to the substrate is compensated for on both sides, thereby preventing deformation.

After sputtering, the operation of replacing the substrate 6 is convenient because by pulling out the substrate holder 6, the spring presser 28 comes off from the ■-shaped groove of the substrate holder support shaft 7, and the substrate holder 6 can be easily removed.

As explained above, according to the present invention, it is possible to instantaneously produce a sputtered thin film on both sides of a substrate, so unlike sputtering in which one side is once exposed to the atmosphere and then re-performed on one side, it is possible to prevent oxidation of the sputtered film and improve the sputtered film application process. Can be shortened.

Furthermore, since sputtering is performed on both sides under the same sputtering conditions, it is possible to produce almost completely homogeneous and uniform films on both sides of the substrate.

Furthermore, as a result, it becomes possible to fabricate a film without causing deformation even on an extremely thin substrate with low mechanical strength.

The present invention can be applied to crystal resonators or optical films used in the watch industry.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram of targets and substrates in a conventional double-sided sputtering apparatus, FIG. 2 is a sectional view of the double-sided sputtering apparatus of the present invention, and FIG. 3 is a partial sectional view of a general single-sided sputtering apparatus. 1... Electrode (target), 2... Sputtering chamber, 3... Substrate, 4... Electrode (
Target), 5... Substrate holder 6...
... Board, 7... Board holder support CBIFT, 8... Bearing shaft, 9...
・Bearing, 10...Bearing holder,
11... Gear cover, 12... Holder fixing base, 13... Rotating ring, 14...
... Large diameter bearing, 15 ... Bearing holder, 16 ... Bearing holder ring, 1
7...Rail, 18...Motor, 1
9... Small gear, 20... Large gear, 21
......Connection shaft, 22...Rotating base ring, 23...Support ring, 24...
... Nut plate, 25 ... L-shaped support plate, 26 ...
...Support ring fixing plate, 27...Spring pin, 28...Spring holder, 29...
Slide shutter, 30... Rotating shutter 31... Gear small, 32... Gear dog, 33... Planetary type board holder.

Claims (1)

[Claims] 1. A sputtering electrode with a flat target attached thereto, and a substrate holder capable of rotating around a rotation axis substantially parallel to the target surface while revolving around the target around an axis perpendicular to the target. , a double-sided sputtering device characterized by forming a thin film on both sides of a flat substrate.