JPH0788574B2 - Reactive high frequency sputtering equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering film forming apparatus, and more particularly to a reactive high frequency sputtering apparatus for controlling the film quality by applying an electric field to an object to be processed during film formation.

[0002]

2. Description of the Related Art A bias sputtering method, in which a film is formed by applying an electric field to an object to be processed during a film forming process by high frequency sputtering, involves adhesion, covering property and film forming density of a film deposited on the object to be processed. It is often used for the purpose of improving the crystallinity of the film.

A high frequency bias sputtering apparatus which achieves this object employs a system in which a DC power source or an AC power source is connected so that a DC bias electric field can be applied to an object to be processed. Among them, the method using the DC power supply is used when the object to be processed and the film formation have high conductivity, and the structure using the AC (high frequency) power supply is clarified in FIG.

That is, the decompression container 1 made of a conductive material such as stainless steel is provided with an exhaust mechanism and a gas introduction mechanism (not shown) so that the pressure can be controlled to a predetermined gas pressure. Further, magnetron sputtering discharge (hereinafter referred to as sputtering discharge) is provided inside. As a component necessary for generating the above), both flat magnetron sputtering electrodes 2 (hereinafter referred to as sputtering electrodes) and the workpiece support mechanism 3 are attached so as to face each other. A target 4 is electrically connected to and installed on the main surface of one flat plate-shaped sputtering electrode 2, and magnetic field generators 5 and 5 shown in FIG. The cooling mechanism provided with is integrally formed. It is additionally noted that the flat plate-shaped sputtering electrodes 2 and 2 shown in FIG. 2 are simplified.

However, in addition to disposing the first insulating layer 7 at the contact portion between the flat plate-shaped sputtering electrode 2 and the decompression container 1 in order to electrically insulate them, a fixing mechanism 8 is used for fixing. In addition, a vacuum sealing mechanism (not shown) is installed on the first insulating layer 7 and the fixing mechanism 8 in order to maintain the airtightness inside the decompression container 1.

The object support mechanism 3 is composed of an object 9, an object holder 10 and a shield plate 11, and a second insulating layer is provided at a contact portion in order to maintain electrical insulation between the decompression container 1. 12, a high frequency power source 13 for bias application is electrically connected to the workpiece support mechanism 3 via a high frequency matching device 14, and a cooling member for the workpiece 9, that is, a flow path 6 is further provided. In addition, a heating member and a moving member are provided side by side.

The operation of such a high frequency bias sputtering apparatus will be described. First, the high frequency power source 13
By applying the high frequency generated from the flat plate to the sputtering electrode 2, a sputtering discharge is generated inside the decompression container 1, and the high frequency current generated through this sputtering discharge is the object to be processed 9 and the shield plate facing the high frequency discharge. 11 and the vacuum vessel 1. Further, due to the negative DC self-bias potential generated on the surface of the target 4 which is a film forming material, the gas ions existing in the discharge space bombard the surface of the target 4 and the target material is scattered. Moreover, the scattered target material is deposited on the surface of the object 9 to be processed, so that a thin film of the target material, that is, a film formation is obtained. In the target material deposition process on the surface of the object 9 to be processed by the high frequency bias sputtering method, a sputtering discharge is generated on the surface of the object 9 to be processed by the high frequency power source 13 for bias application, and the surface of the object 9 to be processed is sputtered like the surface of the sputtering electrode 2. Since a thin film is formed while bombarding with gas ions, a thin film portion having a weak binding force and unnecessary deposited particles can be removed, and a thin film of stable quality can be formed.

In recent years, with the development of LCD technology, it has been required to increase the size of the substrate and improve the productivity, and the mass production equipment shown in FIG. 2 is known. In FIG. 2, parts having the same functions as in FIG. 1 are given the same numbers. That is, a system in which flat plate-shaped sputtering electrodes 2 are installed on both sides of a movable object support mechanism 3 is adopted, and the sputtering film formation is simultaneously performed on two objects to improve productivity. Has advantages. As a structure, airtight isolation valve mechanisms 15 and 15 are installed to divide the decompression container 1 into three parts. In the film forming process, the airtight isolation valve mechanisms 15 and 15 are set in the decompression container 1 and the central portion is set to 10
^{After the pressure is set} to ^-4 to 10 ^-5 Pascal, the workpiece support mechanism 3 having the two workpieces 9 and 9 fixed thereto is inserted by opening the left door 16. Next, the depressurization mechanism is operated to bring it to the same depressurized state as the central portion, and then the airtight isolation valve mechanisms 15 and 15 are released to bring the inside of the depressurized container 1 to a given depressurized state, and then to a given sputtering film forming process. Note that the door 16 on the right side is opened after the high frequency sputtering to take out the processed objects 9, 9. A vacuum seal mechanism (not shown) that can maintain an airtight state is naturally installed on the door 16. The workpiece support mechanism 3 is moved one after another during the sputtering film forming process.

Independent high frequency power source 13 and high frequency matching device 1
6 is a flat plate-shaped sputtering electrode 2 electrically connected,
In the sputtering film forming step 2, the film formation is simultaneously performed while the object support mechanism 3 on which the object 9 is arranged is continuously moved between the flat plate-shaped sputtering electrodes 2 and 2. At the end of this sputtering film forming process, after moving the object support mechanism 3 in which the object 9 is arranged in the right direction of the decompression container 1 in FIG. 2, a large amount of the object 9 to be processed by the above method is deposited. To produce.

[0010]

The high-frequency current generated by the high-frequency power source 13 flows through the workpiece support mechanism 3 and the decompression container 1 which are arranged so as to face the sputtering electrode 2. It also flows to the sputtering electrode 2 and the decompression container 1 which are arranged in the same manner. On the other hand, the high frequency impedance of the decompression container 1 is always constant, but a high frequency is simultaneously applied to the sputtering electrode 2 and the workpiece support mechanism 3, and the impedance due to the alternating electric field is not constant, so a stable high frequency current does not flow. . As a result, an arc discharge is generated on the surface of the object 9 to be processed, and a hollow cathode discharge is generated between the shield plate 11 and the decompression container 1.
It will affect the magnitude of self-bias potential,
It becomes difficult to control the bias potential intentionally.

Moreover, it is difficult to accurately match the oscillating frequency of the high frequency electric field supplied to the sputtering electrode 2 with the oscillating frequency of the high frequency electric field supplied to the workpiece support mechanism 3 due to a change with time of the oscillation circuit constant, and a slight oscillation occurs. The frequency shifts interfere with each other to produce low frequency beats. As a result, the generation of arc discharge and the generation of hollow cathode discharge locally become unstable, and it becomes difficult to generate stable glow discharge between the inner electrodes. Therefore, it becomes difficult to apply the bias electric field with good reproducibility.

Further, in order to stably and reproducibly supply the high frequency power to the moving object 9 to be processed, the high frequency power supply 13 is used.
And the object to be processed 9 must be connected with a constant high-frequency impedance, but when the object to be processed 9 is moved during the film forming process, the impedance of the motion transmission mechanism is constant because the state is constantly changing. It's nearly impossible to maintain.

Further, in the sputtering apparatus shown in FIG. 2, when bias sputtering is performed for the purpose of controlling the film quality, a third high frequency is supplied in the sputtering discharge generated by the flat plate-shaped sputtering electrodes 2 and 2. Due to the movement of the object support mechanism 3, high frequency interference is more complicated and it is difficult to generate a stable sputtering discharge.

FIG. 4 shows a curve in discharge by the flat sputtering electrodes of the sputtering apparatus of FIG. 1 with VDC (voltage V) on the vertical axis and the discharge time on the horizontal axis, but it is extremely unstable. The discharge state is clear.
VDC is a DC self-bias generated in the sputtering electrode when high frequency discharge is performed.

The present invention has been made under such circumstances, and even when the object to be biased is moved between the high frequency sputtering electrodes facing each other during the film forming process, the object to be processed is kept constant. Moreover, it is an object of the present invention to provide a reactive high frequency sputtering apparatus capable of generating a stable bias electric field and eventually capable of mass-producing a high quality sputtering film.

[0016]

Means for Solving the Problems The present invention, the vacuum container
When a high-frequency magnetron sputtering electrode attached to face in the reduced-pressure vessel, the high-frequency magnetron
A target disposed sputtering electrode portion, and a magnetic field device attaching taken in the high frequency magnetron sputtering electrodes, before the inter-frequency magnetron sputtering electrode
Located away from the target , each of the targets
The workpiece can be supported so that it faces the
Object support mechanism and the high-frequency magnetron spa
An oscillator electrically connected to Ttaringu electrode, the object to be punished
A support that constitutes a part of the physical object support mechanism and fixes the object to be processed.
A holding part and a support part formed on the back side of the workpiece.
The notch and the notch are features of the reactive high frequency sputtering apparatus according to the present invention.

Further, a point of applying a magnetic field between the high frequency magnetron sputtering electrodes, a point of varying the magnetic field of a target surface electrically connected to the high frequency magnetron sputtering electrode, and the target surface and the object to be treated. The reactive high-frequency sputtering device is also characterized in that the magnetic field device is provided with a mechanism for varying the distance between the object surfaces.

[0018]

In the reactive high frequency sputtering apparatus according to the present invention, the notch is provided in the workpiece support mechanism and
By insulating between the decompression containers, the impedance of the object to be processed is increased so that high frequency current does not flow. Therefore, there is no DC self-bias generated when a high-frequency current flows through the object to be processed, the object to be processed and the deposited film are not affected by charged particles, and a high-quality sputtered thin film without damage can be formed.

Moreover, the high-frequency current supplied to the sputtering electrodes arranged opposite to each other flows only to the workpiece support mechanism and does not flow to the film deposited on the workpiece. Therefore, problems such as film quality distribution due to reaction change due to unstable inflow of high-frequency current and film thickness reduction due to bias effect do not occur, and reactive sputtering with stable quality can be mass-produced.

In addition, the high frequency applied to the sputtering electrodes arranged opposite to each other is oscillated by the oscillator, and the phase of the high frequency is approximately 180 degrees or 180 degrees ± 3.
By shifting by 0 degree, sputtering discharge can be obtained without causing interference due to frequency shift. Moreover,
Since it becomes possible to maintain a constant high frequency potential of the object to be processed arranged between the sputtering electrodes arranged opposite to each other, in the object to be processed, it is possible to prevent abnormal discharge due to fluctuations in the high frequency potential, A constant DC self-bias potential is generated. Further, by applying a magnetic field in the direction between the opposing sputtering electrodes, the high-frequency current does not flow into the decompression container in the vicinity of the sputtering electrodes and flows into the object to be processed, so that the bias potential increases. Therefore, problems such as abnormal discharge due to interference due to a plurality of high frequencies do not occur. Further, the magnitude of the applied bias potential is controlled by the strength of the magnetic field and the distance between the target and the object to be processed from the sputtering electrode surface.

[0021]

[Embodiment] An embodiment according to the present invention is shown in FIG.
It will be described with reference to FIGS. That is, in the high frequency bias sputtering apparatus according to the present invention, the decompression container can be loaded and unloaded by the airtight isolation valve mechanism and the sputtering film formation can be performed, and the processing target support mechanism supporting the processing target can be used as the sputtering electrode. The sputtering film formation process is performed while the decompression container located between them is stationary or moving.

In the following embodiments, the structure of a movable device will be described. The decompression container 20 made of a conductive material such as stainless steel is divided into three parts by the airtight isolation valve mechanisms 21 and 21 as in FIG. be able to. The object to be processed 22 for depositing a film by sputtering discharge is
It is set on the object support mechanism 23, and this is set in the decompression container 20.
The air-tight isolation valve mechanisms 21, 21 are driven to move in and out of the pressure reducing container 20 into three parts. That is, in order to insert the workpiece support mechanism 23 in which the workpiece 22 is set into the decompression container 20, the decompression container 20 maintained at a predetermined degree of vacuum, for example, 10 ⁻⁵ Pascal, is attached to the airtight isolation valve mechanisms 21 and 21. Set and close the central part. Next, the doors 24, 24 installed in a part of the decompression container 20 and provided with a seal mechanism (not shown) that can be opened and closed and that can maintain an airtight state are opened to an atmospheric state, and then the processing target 22 is set. The processed object supporting mechanism 23 is inserted. Next, after closing the doors 24 and 24, the pressure is reduced to the same degree of vacuum as the central portion, the airtight isolation valve mechanisms 21 and 21 are opened, and the inside of the decompression container 20 is set to the same degree of vacuum to shift to the sputtering discharge.

One or more sets of flat plate-shaped sputtering electrodes 25, 25 necessary for performing the sputtering discharge are placed opposite to each other in the decompression container 20, and an insulating layer 26 is provided at a contact portion with the decompression container 20. Install. Further, as shown in FIG. 8, a magnetic field device 27 and a target 31 described later are continuously formed on the flat plate-shaped sputtering electrodes 25, 25 to be integrated. That is, the flat plate-shaped sputtering electrodes 25, 25, which are heated to a high temperature by discharge, are made of a material having good thermal conductivity, for example, copper, and the magnetic field device 27 is provided in the flat plate-shaped sputtering electrode body 28 made of copper as shown in FIG. And the target 31 is attached to the electrode body 28 by soldering.

The magnetic field device 27 of the present embodiment is provided with a water channel 29 through which a cooling medium flows, and a plurality of magnets 30 ... Enclosing and surrounding the water channel are arranged with different polarities alternately and face each other. Flat plate-shaped sputtering electrode 2 to be arranged
In Nos. 5 and 25, the magnets 30 having different polarities face each other. Further, although it can be moved vertically by the first motor 32, an insulation layer 26 is formed between the decompression container 20 and the flat plate-shaped sputtering electrode body 28 to ensure insulation.

In the magnetic field device 27 having the above structure, since the magnets 30 having different polarities are arranged to face each other, as shown by the arrow in FIG. 8, both flat plate-shaped sputtering electrodes 25, 25. A magnetic force line a in a direction and a magnetic force line b directed to the adjacent magnets 30 and 30 are generated, and the characteristic feature is that the magnetic force line a can be obtained unlike the conventional technique in which magnets of the same polarity are opposed to each other.

The workpiece support mechanism 23 with the workpiece 22 set therein will be described with reference to the plan view of FIG. 6a and the side view of FIG. 6b. An object to be processed 22 for depositing a film, for example, glass is set at 33, and a guide 34 provided with a bearing mechanism is provided at the upper end thereof so that the glass 22 does not fall down. Furthermore, a moving mechanism directly connected to the second motor 35, that is, a roller 36 is installed on the lower support portion 33 to install the glass 22.
Enables the decompression container 20 to move. Also, the object to be processed 2
The material of 2 is not limited to an insulating material such as glass, and a conductive material can be applied.

As is apparent from FIGS. 6A and 7A, a part 33 b of the support portion 33 of the workpiece support mechanism 23 is consequently larger than the size of the film deposited on the workpiece 22.
Increase the impedance to form a notch on 33c. Also ,
As shown in FIGS. 6a and 7a, the workpiece support mechanism 23
Is a rectangular parallelepiped such as a quadrilateral glass substrate.
Supports 33 for fixing both ends of the processed material 22 and back to back
The supporting portion 3 corresponding to the center of the object 22 to be fixed
A notch 33c is formed in the groove 3 .

As shown in FIG. 6, the roller 36 has a first insulating portion 37 made of Teflon at the center of the triple structure.
Is installed to insulate the object support mechanism 23 from the decompression container 20, and FIG. 7A is a top view of the object support mechanism 23 in which the gear structure 38 is installed between the roller 36 and the support portion 33. . Further, FIG. 7B shows an example in which two objects to be processed 22 are attached to the supporting portion 33, and in this case, the second insulating portion 39 is installed on the supporting portion 33. In the above-mentioned embodiment, the method of depositing one kind of material by dividing the decompression container 20 into three parts is shown. However, in order to deposit a plurality of kinds of materials, a plurality of sets arranged opposite to each other in the decompression container 20. The flat plate-shaped sputtering electrode 25 may be installed. In this case, the decompression container 2
0 is provided with one airtight isolation mechanism 21 in excess of the number of flat plate-shaped sputtering electrodes to prepare for the insertion of the workpiece support mechanism 23 as in the above embodiment.

Next, the discharge of the reactive high frequency sputtering apparatus according to the present invention for moving the object to be processed 22 in the decompression container 20 to perform high frequency discharge will be described. For the reference potential and the actual discharge, it is additionally noted that, for example, an argon gas is introduced so that the pressure is reduced to about 10 ^-2 Pascal.

Although such a sputtering discharge can be stabilized by the means to be described later, it cannot generate a controlled bias potential on the object to be processed 22 by itself. That is, when a sputtering discharge is generated, a high-frequency current flows through the workpiece support mechanism 23, which is a counter electrode of the flat-plate-shaped sputtering electrodes 26, 26, so that a self-bias is generated.

However, the high-frequency current flowing changes due to the change in impedance accompanying the movement of the workpiece support mechanism 23, and the self-bias does not become constant.

The flat-plate-shaped sputtering electrode 25 of the reactive high-frequency sputtering apparatus according to this embodiment has a structure shown in FIG.
As shown in (4), it is electrically connected to a high frequency power source through an independent high frequency matching device 40. In addition, as a high frequency power source,
A high frequency oscillator 40, a phase adjuster 41 that distributes the oscillated high frequency into two systems and shifts the phase, an independent power amplifier 42 that amplifies the power and supplies the high frequency to the two flat plate-shaped sputtering electrodes 25, and another power amplifier 43. It consists of.

According to such a configuration, the high frequency oscillator 4
It is preferable that the high frequency oscillated by 0 is shifted by about 180 degrees or 180 degrees ± 30 degrees by the phase adjuster 41, distributed and amplified by the flat plate-shaped sputtering electrodes 25, and supplied.

As a result, even if the oscillation circuit changes over time, the frequency of the high-frequency power supplied to the flat-plate-shaped sputtering electrodes 25, 25 becomes the same, and in the high-frequency sputtering discharge generated by the flat-plate-shaped sputtering electrodes 25, 25. Abnormal discharge due to the difference in frequency does not occur.

In addition, the flat plate-shaped sputtering electrode 2
Since the phases of the high frequencies to be supplied to 5 and 25 are different by approximately 180 degrees or 180 degrees ± 30 degrees, the high frequency potential of the workpiece support mechanism 23 disposed between them is reduced.
It is always kept constant by grounding 0. Therefore,
The target object support mechanism 23 and the decompression container 20 are changed due to potential fluctuations in the decompression container 20 in which the object support mechanism 23 is arranged.
No abnormal discharge occurs in the meantime.

The sputtering discharge generated by such a structure can be stabilized, but with this alone,
It is not possible to generate a controlled bias potential on the object to be processed 22. Therefore, the means focusing on the impedance as described above is adopted.

Next, VDC which changes in accordance with the change of discharge
For the above, the vertical axis represents the VDC voltage (V) and the horizontal axis represents the discharge time (minutes), and the relationship between the two will be examined with reference to FIGS. 9, 10 and 11. That is, the difference in the VDC voltage between the workpiece support mechanism 23 and the decompression container 20 depending on the presence or absence of insulation is clearly shown. Comparing both curves, the insulated FIGS. 10 and 11 are much more stable. There is.

First, in the case of the conventional technique, that is, when the phase of the oscillator is not shifted, an extremely large fluctuation appears (FIG. 4).
10), it is much flatter, which clearly shows the effectiveness of the present invention. However, in the curve of FIG. 9, a somewhat large fluctuation appears periodically, whereas what does not appear in FIGS. 10 and 11 is that the roller 3 attached to the workpiece support mechanism 23 as described above.
It is caused by the presence or absence of insulation such as 4. Figure 11
Shows the case where the phase of the oscillator is shifted by approximately 180 degrees, and the stable discharge state is clearly shown as compared with the case where the phase is shifted by 180 degrees ± 30 degrees in FIG.

Further, in the reactive high frequency sputtering apparatus according to the present invention, since the magnets having different polarities are arranged so as to face each other, the magnetic force line a in the direction of the flat plate-shaped sputtering electrode is generated. The bias potential flowing through the object to be processed becomes large.

[0040]

As described above, in the reactive high frequency sputtering apparatus according to the present invention, stable bias sputtering discharge can be generated, and even if an insulating material is used as a target material, stable deposition and film formation can be obtained. To be Moreover, the productivity can be doubled by disposing the two objects to be processed facing the flat plate-shaped sputtering electrode. In addition, it is a reactive high-frequency sputtering apparatus that can exhibit remarkable effects such as desired bias potential control and desired sputtering film formation, and has high productivity.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of a conventional reactive high frequency sputtering apparatus.

FIG. 2 is a cross-sectional view showing a main part of another conventional reactive high-frequency sputtering apparatus.

FIG. 3 is a cross-sectional view of a magnetic field device installed in a conventional reactive high frequency sputtering device.

FIG. 4 is a curve diagram showing a VDC voltage that changes according to a discharge time in a conventional reactive radio frequency sputtering apparatus.

FIG. 5 is a sectional view showing a main part of a reactive high frequency sputtering apparatus according to the present invention.

FIG. 6 is a view showing a workpiece support mechanism 23 installed in the reactive high frequency sputtering apparatus according to the present invention.
6a is a top view thereof, and FIG. 6b is a side view thereof.

FIG. 7 is a diagram showing another workpiece support mechanism installed in the reactive high-frequency sputtering apparatus according to the present invention.
7a is a top view thereof, and FIG. 7b is a side view thereof.

FIG. 8 is a cross-sectional view of a magnetic field device installed in the reactive high frequency sputtering device according to the present invention.

FIG. 9 is a curve diagram showing a VDC voltage that changes in accordance with a discharge time when insulating between a workpiece mechanism and a decompression container in the reactive high frequency sputtering apparatus according to the present invention.

FIG. 10 relates to the device of the present invention provided with an insulated workpiece support mechanism, and oscillates a high frequency phase of 180 ° ± 30.
It is a curve figure which shows the VDC voltage which changes according to the discharge time in the reactive high frequency sputtering device which staggered.

FIG. 11 is a curve diagram showing a VDC voltage which changes corresponding to a discharge time in a reactive high frequency sputtering apparatus in which the phase of an oscillating high frequency is shifted by 180 degrees according to the present invention, which is provided with an insulting object supporting mechanism. Is.

[Explanation of symbols]

 20: Decompression container, 21: Airtight isolation valve mechanism, 22: Object to be processed, 23: Object support mechanism, 24: Door, 25: Sputtering electrode, 26: Insulator layer, 27: Magnetic field device 28: Sputtering electrode body , 29: water channel, 30: magnet, 31: target, 32, 35: motor, 33: support part, 33b: part of support part, 33c: notch of support part, 34: guide, 36: roller, 37, 39: insulating part, 38: gear, 40: high frequency matching device, 41: high frequency oscillator, 42: phase adjuster, 43, 44: power amplifier.

Front Page Continuation (72) Inventor Yoshimi Kuroda 6-31-1, Kameido, Koto-ku, Tokyo Seiko Electronics Co., Ltd. (56) Reference JP-A-2-298268 (JP, A) JP-A-62 -188777 (JP, A)

Claims (1)

[Claims] 1. A pressure reducing container, the high-frequency magnetron sputtering electrode attached to face in the reduced-pressure vessel, before
Placed on the high frequency magnetron sputtering electrode part
And targets, the magnetic field device attaching taken in the high frequency magnetron sputtering electrodes, located away from the target between the high-frequency magnetron sputtering electrode
And, the to opposed to the respective target
And the object to be treated support mechanism capable of supporting treated, before
Electrically connected to the high frequency magnetron sputtering electrode
A continuous oscillator and a part of the workpiece support mechanism.
Support part for fixing the object to be processed, and back surface of the object to be processed
A reactive high-frequency sputtering apparatus, characterized in that it is provided with a notch formed in the supporting part on the side thereof.