JPS63192865A - Sputtering device - Google Patents

Abstract

PURPOSE:To widely and precisely control the deposition amt. of each element by providing plural sputtering chambers independently connected to a central vacuum vessel on the outside of the vessel, and arranging a variable aperture in each sputtering chamber to prevent the contamination of each target. CONSTITUTION:Plural sputtering chambers 4a-4d independently connected to the central vacuum vessel 2 and an observation chamber 6 are provided on the outside of the vessel. A gas such as Ar for generating electric discharge is introduced into the central vacuum vessel 2, and exhausted from the respective sputtering chambers 4a-4d and the observation chamber 6 through each communicating window 14. A substrate holding mechanism 8 is rotated, the variable apertures 64 of the selected sputtering chambers 4a-4c, for example, are closed, and sputtering is carried out. When a multiple-element compd. is formed by sputtering, each target 60 is simultaneously sputtered. When a multilayer thin film is formed, the variable apertures 64 of the sputtering chambers 4a-4d are successively opened, and each target 60 is sputtered in the laminating order.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sputtering apparatus having a plurality of sputtering chambers for a substrate.

[Prior Art] In recent years, forming multi-compound thin films, multilayer thin films, etc. by sputtering has attracted attention.

In the case of a multi-component compound thin film, there are two methods: ■ A method of performing sputtering using the target multi-component compound as a target, ■ A method of providing a target for each element that makes up the multi-component compound and sputtering these targets simultaneously, ■ A method of sputtering each element that makes up the multi-component compound A method has been proposed in which sputtering is performed by arranging the materials on one target at an appropriate area ratio.

On the other hand, in the case of multilayer thin films, ■ a method in which targets are provided for each component element of each layer, these targets are placed on the same circumference, and the substrate is sequentially moved on the circumference for sputtering; A method has been proposed in which targets are provided for each element, these targets are arranged in a straight line, and the substrate is sequentially moved along the straight line for sputtering.

[Problems to be Solved by the Invention] However, the above-mentioned conventional methods have the following problems for both multicompound thin films and multilayer thin films.

That is, in the case of a multicomponent thin film, in method (2), in which sputtering is performed using a multicomponent compound as a target, the sputtered atoms are generally used as targets.

cannot be expected to adhere to the substrate in the same composition ratio as the multi-component compound, and it is necessary to replenish part of the vapor of the multi-component compound or a gas containing some of the constituent elements of the multi-component compound. Therefore, there is a problem in that the range of compounds to which this method can be applied is limited.

In method (2), in which targets for each constituent element are sputtered simultaneously, a substrate is placed on a plane parallel to the target plane, and this substrate is rotated about an axis perpendicular to the target plane so that each element is sputtered uniformly or as desired. At the same time, the amount of each component element attached is controlled by changing the electric power supplied to each target to obtain a film having a desired composition ratio. However, the range in which the power supplied to each target can be varied is narrow due to the need to maintain discharge, and the amount of adhesion of each component element must also be controlled within a narrow range.Therefore, this method However, it has the disadvantage that it is difficult to form thin films with arbitrary composition ratios over a wide range.

Moreover, in this method, the substrate is placed on a rotating disk parallel to a plurality of target surfaces, so the area where the composition ratio is the same is narrow, and this method has the disadvantage that it is not suitable for mass production.

Furthermore, there is a problem in that some elements to be sputtered tend to combine with elements of other targets and contaminate the target surface. Contamination of the target not only adversely affects composition control, but also causes the problem of unstable discharge if the specific resistance of the contaminated target surface changes.

In method 2, in which sputtering is performed by arranging each element constituting a multi-component compound in a suitable area ratio on a single target, the composition ratio cannot be changed without changing the composition of the target. Depending on the element used, the target may be contaminated, causing problems similar to those described above.

On the other hand, in the case of multilayer thin films, methods ① and ③ in which sputtering is performed by sequentially moving the substrate under the component element target of each layer, control the film thickness of each layer by changing the amount of deposition by changing the supplied power. Therefore, as described above, the range in which the amount of adhesion can be changed is limited, and the range in which the film thickness can be controlled is narrow. Furthermore, the above method (1) has the disadvantage that depending on the sputtering element, the target may be contaminated, causing the same problem as above.

Note that the above method (1) has the advantage that contamination of the targets can be prevented by configuring a sputtering chamber for each target. however.

The above method (2) has the disadvantage that the R& film takes time when multiple layers of each element constituting the multilayer film are deposited.

The present invention was made to solve the above-mentioned problems, and its first purpose is to be able to sputter a plurality of targets independently for each target, to prevent contamination of each target, and to The object of the present invention is to provide a sputtering apparatus that can precisely control the amount of each element deposited over a wide range.

A second object of the present invention is to provide a sputtering apparatus that can precisely set the composition ratio, film thickness, addition amount, etc. and is suitable for forming multi-component thin films, multilayer thin films, superlattice thin films, etc. It is in.

[Means for Solving the Problems] As a means for solving the above problems, the present invention includes a central vacuum chamber and a plurality of sputtering chambers each independently connected to the outside of the central vacuum chamber. A substrate holding mechanism is provided in the tank so as to be able to rotate once, and holds the substrate on the outer peripheral side surface.

A window is provided at a connecting portion between the central vacuum chamber and each sputtering chamber to communicate with the substrate held by the substrate holding mechanism so that a sputtering film can be formed.

Further, the sputtering chamber is characterized in that a variable aperture is disposed at a position in front of the substrate in the sputtering chamber.

It is preferable that each of the sputtering chambers is connected to an exhaust system so as to be evacuated, however,
The exhaust system itself may be the same.

It is preferable that the central vacuum chamber and the substrate holding mechanism disposed therein be formed into a single cylindrical shape, and both are arranged concentrically. In addition, when the central vacuum chamber and the substrate holding mechanism are arranged, the gap between the inner circumferential surface of the former and the outer circumferential surface of the latter is
It is desirable to have a configuration in which they can be arranged as close together as possible to make the space as narrow as possible.

The variable diaphragm disposed at a position in front of the substrate in the connecting portion may have any form as long as it can control the amount of elements attached to the substrate from the sputtering chamber side through the communication window, for example, It may be a thank you note or a slit.

Further, it is preferable that this variable aperture has a structure that allows the so-called π operation of the NI date from outside the sputtering chamber, and furthermore,
Preferably, it has a structure that can be fully opened and closed so that it can be used as a shutter. Of course, a shutter may be provided separately from the variable aperture.

[Operation] The present invention configured as described above operates as follows.

The substrate holding mechanism is arranged in a central vacuum chamber, and a plurality of sputtering chambers are provided independently outside the central vacuum chamber, so that each sputtering chamber can perform sputtering independently. The power used can be changed for each sputtering room, or it is different for each sputtering room! ! types of targets can be placed. Of course, multiple targets of the same type can be arranged, and some sputtering chambers can also be kept as spares, and these spare sputtering chambers can be used for substrate observation or as vapor deposition chambers. You can also do that.

In each sputtering chamber, the material sputtered and ejected from each target enters the central vacuum chamber from the sputtering chamber through the window, and adheres to the substrate at the position of each layer. On this occasion.

When the substrate holding mechanism is rotated at high speed and each target is sputtered at the same time, elements from the targets in each sputtering chamber will be mixed and adhered to each substrate held, and conditions such as substrate temperature may be set appropriately. As a result, the attached elements are combined to form the desired multi-compound thin film.

Further, in the present invention, since a variable aperture is disposed in front of the substrate in the sputtering chamber, by adjusting the aperture of the aperture, the amount of sputtering material passing through the aperture per unit time, that is, the amount of each element The amount of substrate adhesion can be controlled. Therefore, the abundance ratio of elements attached to the substrate can be set, and a multi-compound thin film can be formed with a desired composition ratio. At the same time, the film thickness can also be precisely set.

On the other hand, a multilayer film can be formed by rotating the substrate holding mechanism and ejecting corresponding elements from each sputtering chamber in the order of lamination starting from the bottom layer. On this occasion,
Similarly to the above, the film thickness of each layer can be controlled by setting the aperture to an appropriate aperture. It is also possible to control the film thickness by changing the rotation speed of the substrate holding mechanism for each layer. The rotation speed of this substrate holding mechanism is IJ
ffi determines the time during which the substrate passes in front of the aperture opening of each sputtering chamber, and as a result, the total amount of sputtering material deposited on the substrate can be precisely set.

Further, in the present invention, since each sputtering chamber is independent, sputtering substances from targets in other sputtering chambers are hardly attached to the substrate in front of a certain sputtering chamber, and the targets in each sputtering chamber are It is also prevented that the sputtering chambers are contaminated by elements ejected from targets in other sputtering chambers.

Note that the above action works more effectively as the outer circumferential side of the substrate holding mechanism and the inner circumferential side of the central vacuum chamber are brought closer together.
That is, as the two come closer together, the gap between the two becomes narrow enough to prevent the sputtered material from going around to the position of the substrate in front of the adjacent sputtering chamber.

According to the sputtering apparatus of the present invention, in the case of a multicomponent thin film, it is possible to set the composition ratio to a desired value over a wide range, and the film thickness can also be set to a desired value accurately. Furthermore, in the case of a multilayer thin film, the thickness of each layer and the overall thickness can be precisely controlled.

Furthermore, according to the present invention, the elements can be uniformly attached to the entire outer peripheral side surface of the substrate holding mechanism, so the area where a compound with the same composition ratio or a layer with the same thickness can be formed is wide. Therefore, multicomponent thin films or multilayer films can be formed on a large number of substrates, facilitating mass production. Moreover,
In each sputtering chamber, an optimal discharge state can be maintained, making it possible to perform stable and highly efficient sputtering and achieve high-speed film formation.

〔Example] An embodiment of the present invention will be described with reference to one drawing.

<Configuration of Example> FIG. 1 shows the structure of an example of the sputtering apparatus of the present invention.

The sputtering apparatus of the embodiment shown in the figure includes a central vacuum chamber 2, a plurality of sputtering chambers 48 to 4d provided outside the central vacuum chamber 2 and connected to each other independently, and an observation chamber 6. 2, a substrate holding mechanism 8 which is rotatably provided and which holds the substrate on the outer peripheral side surface thereof is arranged.

The central vacuum chamber 2 is made of metal, stainless steel in this embodiment, and has a cylindrical shape with its lower end closed by a base plate IO and its upper end open. An upper lid 12 is placed on the upper end via a gasket (not shown) to enable vacuum sealing. Furthermore, communication windows 14 are provided in the side surfaces of the central vacuum chamber 2 at the portions where the sputtering chambers 48 to 4d and the observation chamber 6 are connected. In this embodiment, the communication window 14 has a rectangular cross section.

Inside the central vacuum chamber 2, there is a substrate holding mechanism 8, which will be described later.
A rotary support section 16 is provided which supports the substrate and is equipped with a heater 20 for heating the substrate. This rotation support part 16 is
As shown in Figure 3, its lower end side is the base plate l.
It is placed and fixed on O. Further, a bearing 18 is provided at the center of the upper surface of the rotation support portion 16 .

The heaters 20 are, for example, infrared heaters, and a plurality of heaters 20 are arranged along the inner circumferential surface of the rotary support portion 16. In this embodiment, the arrangement position is each sputtering chamber 48 to 4d.
and each communication window 14 of the observation room 6. These heaters 20 are connected to an external power source via current introduction terminals 22 provided on the base plate 10, as shown in FIG. Note that a window 17 is provided in a portion of the one-turn support portion 16 adjacent to the heater 20 to allow infrared rays to pass therethrough.

Each of the sputtering chambers 48 to 4d and the observation chamber 6 are basically formed with the same external shape. That is, each of them is formed into a substantially cylindrical shape, and one end side is connected and fixed to the side circumferential surface of the central vacuum tank, and the other end side, sputtering chambers 48 to 4d, are vacuum-sealed by the target holding part 24. The observation chamber 6 is vacuum-sealed by an observation window holder 26.

These sputtering chambers 4a to 4d and the observation chamber 6 are each independently connected to the central vacuum chamber 2, and in this embodiment, each is attached centered at a position corresponding to the apex of a regular pentagon. Further, these sputtering chambers 48 to 4d and the observation chamber 6 are each connected to an unillustrated exhaust system via a vacuum pipe 80, and are individually evacuated. However, the exhaust system may be shared. In this embodiment, the central vacuum chamber 2 itself is not individually evacuated, but the sputtering chambers 48 to 4d and the observation chamber 6 are evacuated through the communication window 14. Ru.

The upper lid 12 is made of a stainless steel plate, and has a rotating introducer 28 in its center, and a gas inlet 30 and a thermocouple 32 for monitoring substrate temperature in its periphery. . All of these are vacuum sealed.

The rotation introducer 28 is formed in the shape of a shaft and passes through the upper lid 12, and is provided with a drive-side joint part 34 on the lower side that connects with and rotates the substrate holding mechanism 8, which will be described later, and on the upper side. A rotary drive mechanism 38 consisting of a motor and a gear box is connected to the rotary drive mechanism 38. The driving side joint part 34 is provided with a protrusion 36 that engages with a passive side joint part 44 to be described later to transmit rotation.

Further, in this embodiment, as shown in FIG. 1, an airlock type substrate introduction mechanism 40 is provided on the upper lid 12.

The substrate holding mechanism 8 inserted into the central vacuum chamber 2 is formed in a cylindrical shape, and the upper side is closed by a flat plate 42, and the passive side has a hole 45 in the center of the flat plate 42 that engages with the protrusion 36. A joint portion 44 is provided. Further, on the outer peripheral side surface of the substrate holding mechanism 8, five grooves 46 are formed at equal intervals around the circumference.
locations, that is, the sputtering chambers 48 to 4d and the observation chamber 6
This is provided in response to this. A substrate holder 48 is attached to each of the grooves 46 .

The substrate holder 48 is formed to have a trapezoidal cross section, and is structured to fit into the groove 46 like a dovetail. A substrate 50 is mounted and held on the front side of the substrate holder 48.

Furthermore, a screw hole 52 is provided at the upper end of the holder 48 . A screw of a holder attaching/detaching mechanism (not shown) in the substrate introduction mechanism 40 described above is screwed into this screw hole 52, and the holder 48 is attached/detached to/from the substrate holding mechanism 8 by the attaching/detaching mechanism.

The target holder 24 provided in the sputtering chambers 48 to 4d is inserted into each of the cylindrical sputtering chambers 43 to 4d via an O-ring 54, as shown in FIGS. 2 and 3. Flanges 56 of sputtering chambers 4a to 4d
It is fixed with bolts 58. The insertion depth of this holding portion 24 can be adjusted by tightening the bolt 58.

The target holding section 24 holds the target 60 and the water-cooled electrode 6.
2 and hold. In this case, since a high voltage is applied to the water-cooled electrode 62, it is held by the insulating member 78. The water-cooled electrode 62 is provided with a water supply and drainage section, into which cooling water is injected to cool the target 60.

Furthermore, a variable aperture 64 is provided in the sputtering chambers 48 to 4d. In this embodiment, the diaphragm 64 is provided close to the front of the communication window 14.
b, and an aperture opening/closing mechanism 68 that drives the shielding plate 66a166b to open and close.

The shielding plates 66a and 66b are made of stainless steel, and their lower sides are slidably fitted into the sill grooves 70.

Further, the diaphragm opening/closing mechanism 68 includes a zero rotation shaft 72 consisting of a rotation shaft 72 that constitutes a feed spiral, and nut portions 74a and 74b that are screwed into threads (not shown) provided on the rotation shaft 72.
The threads provided on the shield plate 2 are provided corresponding to the shielding plates 66a and 66b, and the direction of rotation thereof is reversed left and right. Therefore, when the rotating shaft 72 is rotated, the nut portions 74a, 7
4b will move in opposite directions. Further, the nut portions 74a and 74b each have a corresponding shielding plate 66a.
, 66b, and as the rotating shaft 72 rotates, the shielding plates 66a, 66b are moved along the axial direction of the rotating shaft 72.

One end of the rotating shaft 72 protrudes to the outside of the sputtering chambers 48 to 4d via a vacuum seal. Therefore, in each sputtering chamber 48 to 4d, the aperture 64 can be used without breaking the vacuum.
The degree of opening can be adjusted. In this case, the aperture 64
The degree of opening can be set by the rotation speed of the rotating shaft 72.

Further, an observation window 7 is provided on the outer peripheral side of the sputtering chambers 48 to 4d.
6 is provided so that the discharge state can be observed.

<Operation of Example> The operation when forming a thin film using the sputtering apparatus of this example configured as described above will be described.

As a preparatory work, first select the sputtering chamber to be used from among the sputtering chambers 48 to 4d. The water-cooled electrode 62 is attached to the target holding section 24, and the holding section 24 is attached to the corresponding sputtering chambers 4a to 4c. At this time, bolt 58
Adjust the insertion depth and set the electrode spacing to the desired value by tightening.

On the other hand, the substrate holder 48 with the substrate 50 attached thereto is attached to the substrate holding mechanism 8, this holding mechanism 8 is inserted into the central vacuum chamber 2, and the opening of the central vacuum chamber 2 is further sealed with the upper lid 12. and start exhausting. At this time, the drive side joint part 34
and the passive joint portion 44 are engaged to transmit one rotation.

The inside of the vacuum chamber 2 is set to a high vacuum (e.g. tx 10-'Torr)
After removing residual impurity gas, a gas for discharging, for example, high-purity A gas, is introduced into the central vacuum chamber 2 from the gas inlet 30. 2 through the communication window 14 to each sputtering chamber 48 to 4.
d and the observation room 6. The amount of gas introduced is the optimal equilibrium partial pressure.

For example, it is adjusted and maintained at about sx 10-'' Torr.Although not shown in this embodiment, a magnet is placed behind the target 60 to enable discharge at a low gas pressure.

During this time, the substrate 50 is baked by the heater 20 and is maintained at a predetermined temperature, for example, 200"C, as measured by the substrate temperature monitoring thermocouple 32. In this case, the temperature is automatically maintained at the predetermined temperature by feedback control. You may also do so.

Further, the 0 rotation speed at which the substrate holding mechanism 8 is rotated by the rotation drive mechanism 38 via the rotation introducer 28 is, for example, 0 rotation speed.
．． 1rp- to 500rp■0 Usually, when forming a multi-compound thin film, the speed is high, and when forming a multilayer film, the speed is low. Of course, sputtering can be performed without rotating the substrate holding mechanism 8, and instead of continuous rotation, the substrate holding mechanism 8 may be rotated step by step at a constant angle.

In each sputtering chamber, 48 to 4c in this embodiment, the aperture 64 is completely closed and press battering is performed.In this embodiment, the variable aperture is also used as a shutter, but the apparatus is equipped with a separate shutter. If so, close the shutter. Thereafter, the rotating shaft 72 is rotated to open the aperture 64 to a predetermined opening degree. The opening degree is set in consideration of the rotation speed of the rotating shaft 72 and the required amount of deposit.

When sputtering, select DC power or high-frequency power according to the electrical resistance of the target material. For example, use high-frequency power for high-resistance materials such as Se, and use low-resistance materials such as Cu and In. DC power is used for these.

Under such preparation, when forming a multicomponent thin film, each target 60 is sputtered simultaneously.

On the other hand, when forming a multilayer thin film, each target 60 is sputtered in the order of stacking. In this case, it is preferable to perform sputtering on each target 60 at the same time, and to sequentially open the variable aperture 64 as a shutter only when necessary, to selectively allow the target material to reach the substrate and form a multilayer film.

Note that each target 60 is cooled by circulating cooling water through the water-cooled electrode 62.

Further, the state of formation of the thin film can be observed through the observation window of the observation chamber 6.

<Experimental Example> Next, an experimental example of thin film production using the above apparatus will be described.

(a) Experimental example 1, r Cu1nSet multi-compound thin film. Three chambers 4a to 4c were selected from sputtering chambers 4a to 4d, targets of Cu, In, and Se were attached to them, and The substrate was mounted on the substrate holding mechanism 8, and these were mounted on the apparatus of this embodiment, and the inside of the vacuum chamber 2 was evacuated to about lx 10-'Torr.

After removing residual impurity gas, high purity Ar gas was introduced. This Ar gas pressure is sx during sputtering.
The temperature of the glass substrate mounted and held in the substrate holding mechanism 8 was maintained at 200°C.

In the above atmosphere, while rotating the substrate holding mechanism 8 at a rotation speed of 100 rpm, high frequency power (1001) was supplied to the Se target, and DC power (0.3 KV, 100 mA) was supplied to the Cu and In targets. , sputtering was performed. At this time, the aperture of each variable diaphragm 64 was set for each target as follows.

Cu= (7X 50)■■禦In・-(6x50)■■Mayuzumi5e---(0,76X 50)as'' When sputtering was performed as described above, the deposition rate was 600 people per hour. Black and shiny.

A thin film was formed. When the obtained film was examined by X-ray diffraction, it was found that the film had a chalcopyrite structure.
It was confirmed that it was a u1nSe2 polycrystalline film.

In addition, as a result of composition analysis using an X-ray microanalyzer,
What is the composition ratio of the obtained film?

Cu-23at$, In-27atl,
5e=50at$.

Note that no contamination due to attachment of Se was observed for each of the Cu and In targets.

(b) Experimental Example 2, r Cu-In-8e Multilayer Thin Film The substrate holding mechanism 8 was rotated at a rotation speed of 0.1 rpm, the substrate temperature was set to room temperature, and the variable aperture 64 corresponding to each target was used as a shutter. , Cu (100) in (3
A multilayer film was obtained in which layers of Cu (100), Se (80), Cu (100), 5e (80), and Cu (100) were laminated.

In addition, for each target of Cu and In, Se
No contamination due to adhesion was observed.

<Other Examples> In the above example, four sputtering chambers and an observation chamber were provided outside the central vacuum chamber, but all of them may be used as a sputtering chamber, or a part of the sputtering chamber may be used as a preliminary chamber. It can also be used as an observation room. Furthermore, a part can also be used as a vapor deposition chamber.

In the above embodiment, five rooms including the observation room are provided, but the number is not limited to this, and the number of sputtering rooms can be decreased or increased.

In addition, although the above examples show examples of use in forming multi-element compound thin films and multilayer thin films, it can also be used to add trace amounts of other substances into semiconductors and dielectrics. When introducing impurities, the semiconductor can be added by using the semiconductor as a substrate, using the impurity as a target, making the aperture of the aperture very small, rotating the substrate holding mechanism at high speed, and performing sputtering. However, if the semiconductor is a thin film, it is also possible to add impurities while forming the semiconductor itself by sputtering.

[Effects of the Invention] As explained above, the present invention enables sputtering of a plurality of targets independently for each target, prevents contamination of each target, and allows the deposition amount of each element to be varied over a wide range. It also has the effect of allowing precise control.

Therefore, according to the present invention, it is possible to easily produce a multi-component thin film with a precise composition ratio, a multilayer thin film in which the thickness of each layer is accurately set, and even a superlattice thin film.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of the main parts showing the structure of an embodiment of the sputtering apparatus of the present invention, FIG. 2 is a cutaway plan view of the main parts showing the structure of the central vacuum chamber and sputtering chamber in the above embodiment,
The figure is a sectional view showing the structure of a central vacuum chamber and a sputtering chamber. 2... Central vacuum chamber 48-4d... Sputtering chamber 6... Observation chamber 8... Substrate holding mechanism 10.
・Base plate

Claims (1)

[Scope of Claims] A central vacuum chamber and a plurality of sputtering chambers each connected to the outside of the central vacuum chamber are provided, the sputtering chamber being rotatably provided in the central vacuum chamber and holding a substrate on an outer peripheral side surface thereof. a substrate holding mechanism for forming a sputtering film on the substrate held by the substrate holding mechanism, and a window communicating with the substrate held by the substrate holding mechanism so as to form a sputtering film on the substrate held by the substrate holding mechanism; A sputtering device characterized by having a variable diaphragm arranged at a front position.