JPH0813143A - Plasma treatment and treating device - Google Patents

Abstract

PURPOSE:To provide a method capable of simultaneously and accurately treating both surfaces of a substrate even if this substrate is not a conductor at the time of subjecting both front and rear surfaces of the substrate to thin film formation and the plasma treatment, such as etching and heating and a device therefor. CONSTITUTION:A circuit for impressing high-frequency potential between a first target electrode 5 and a second target electrode 3. A substrate holding mechanism 21 is so formed that an electrically insulated state is maintained between this mechanism and the high-frequency circuit except at the contact point with the substrate 9. The first target electrode 5 is connected to a high-frequency power source 14 via a capacitor 35 and a matching device 13. A bias current flows via the capacitor between both surfaces of the substrate when a potential difference (bias potential) is generated between two plasmas 10 and 8. As a result, a high-frequency electric field is generated on both front and rear surfaces of the substrate to accelerate incident ions. The evaporation of film by a current concentration at the contact points of the electrodes with the substrate surfaces like heretofore and the consequent abnormal discharge and bias impression defect do not arise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for performing plasma processing such as thin film formation by bias sputtering or CVD on a substrate such as a magnetic disk, etching processing and heating on the both sides of the substrate. The present invention relates to a suitable method and apparatus for performing plasma processing on both surfaces of a substrate even when the electrical control is not performed by bringing a conductor into contact with the substrate.

[0002]

2. Description of the Related Art As a method for forming a thin film by bias sputtering on both surfaces of a substrate typified by a magnetic disk, for example, as disclosed in Japanese Patent Application Laid-Open No. 3-283111, a thin film is formed between two opposing target electrodes. , The surface of the conductive substrate is placed toward each target electrode, plasma is generated on the target electrode by applying a negative potential to each target electrode, the target surface is sputtered by the ions in the plasma, Particles of the scattered target material are attached to the surface of the substrate.
At this time, a method is known in which an AC or negative DC potential is applied to the substrate holding mechanism to apply an AC or negative DC potential to the surface of the substrate via a holding claw of a conductor that contacts the edge of the substrate.

Further, as described in, for example, Japanese Patent Laid-Open No. 4-79025, when the substrate is an insulator, a conductive film is previously formed on the substrate surface to hold the substrate surface and the conductor. Methods for obtaining electrical contact with the nail are also known. Due to the bias potential applied to the substrate surface via the holding claws, the ions in the plasma also collide with the substrate surface, giving its energy to the surface molecules being deposited,
It is also known that the crystallinity of the formed film is enhanced and the magnetic properties are improved.

Further, as described in, for example, Japanese Unexamined Patent Publication No. 5-140752, conventionally, a method of forming a carbon film on both surfaces of a substrate by plasma CVD is similar to the above-mentioned two conventional examples in that the substrate is placed on a substrate holding mechanism. It is placed and electrically connected to the substrate by contact with the substrate holding claw. This substrate holding mechanism is grounded, two electrodes facing each other across the substrate are placed in a vacuum vessel, the inside of the vacuum vessel is evacuated to a high vacuum, and a process gas such as methane is used as a film-forming source gas at a predetermined pressure. Introduce. A high frequency power source is connected to each of the two electrodes, and high frequency power is applied to the ground potential. Plasma is generated between each electrode and the substrate by the applied high-frequency potential, and from the high-frequency power source, → electrode → plasma →
A high-frequency current flows through the path of substrate → substrate holding mechanism → ground → high-frequency power source, and a potential difference occurs between the substrate and plasma. At this time, the processing gas ionized on the substrate surface is accelerated by the electric field generated on the substrate surface and collides with each other to form a high-strength carbon film on the substrate surface.

[0005]

However, in these examples, when the substrate is made of an insulating material such as glass, the current flowing between the substrate holding mechanism and the substrate is at the contact portion between the substrate holding mechanism and the substrate. Since no potential difference is generated between the substrate surface and the plasma due to the shielding, it is not possible to expect a film quality improving effect or a film forming effect by ion bombardment on the film forming surface. Even if the material to be formed is a conductive film such as a metal, the surface of the substrate becomes conductive, but the area around the contact point with the substrate of the substrate holding mechanism is shaded, and therefore the film is not formed around the contact point. Therefore, the conductive film deposited on the substrate surface and the substrate holding mechanism cannot make electrical contact with each other, and a bias potential cannot be generated on the substrate surface.

Further, as described in Japanese Patent Application Laid-Open No. 4-79025, the method of previously forming a conductive film on the surface of an insulating substrate not only complicates the film forming process, but also causes the holding claw and the substrate to be separated. The contact point between the two has a very small area, and the conductive film is rapidly heated by the electric current concentrated there, and there is a problem that the conductive film is often evaporated to cause electrical contact failure or damage the substrate.

Therefore, an object of the present invention is to solve these problems of the prior art, and the first object is to apply a bias potential directly to the substrate to be processed from the outside through the substrate holding mechanism. Even if it does not exist, an effect equivalent to applying a bias potential between the both sides of the substrate to be processed is obtained, and an improved plasma processing method capable of easily passing a high frequency bias current between the front and back surfaces of the substrate is provided. In particular, a second object is to provide a processing device that realizes it.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted various experiments to solve the above problems, and as a result, have obtained effective knowledge as described below. That is, a high-frequency potential is applied between the plasmas generated on both sides of the substrate, and a high-frequency current is caused to flow from one plasma through the substrate to the other plasma by the capacitance between the front and back surfaces of the substrate. It is possible to accelerate the incident ions to the substrate surface by the bias electric field.

As a method of applying a high frequency potential between these two plasmas, a relative high frequency potential is applied to an electrode other than the substrate in contact with each plasma, or a high frequency potential different in phase from a certain reference potential. By applying. At this time, the substrate is electrically insulated from the substrate holding mechanism, the substrate holding mechanism is electrically insulated from a portion other than the substrate, or the substrate holding mechanism is applied to the plasma. It may be electrically insulated from the high frequency current circuit.

The present invention has been made based on the above findings, and the means for achieving the object of the present invention will be specifically described below. That is, the first object is a method of generating plasma on both sides of a substrate to be processed placed in a vacuum container to perform plasma processing on both sides simultaneously, and applying high frequency energy to the at least one plasma. This is achieved by a plasma processing method in which a potential difference is generated between these two plasmas and a high frequency current is caused to flow between the front and back surfaces of the substrate.

As a method of applying the high frequency energy to the plasma, one of the plasmas is applied as described above, and the other plasma is not applied, and a potential difference is generated between the two plasmas. , A high-frequency current is caused to flow between the front and back surfaces of the substrate, or high-frequency energy having a different phase is applied to both plasmas to generate a potential difference between the two plasmas, so that the surface of the substrate is A high frequency current may be passed between the back surfaces.

The plasma processing method of the present invention can be applied to generally known plasma processing methods such as a film forming method by sputtering or CVD, a plasma etching method, a plasma ashing method and the like.

A second object is to mount a vacuum container, an exhaust means for exhausting the inside of the vacuum container to a high vacuum, a means for supplying a processing gas into the vacuum container, and a vacuum container. A substrate to be processed, a substrate holding mechanism for holding the substrate to be processed,
A substrate to be processed is sandwiched, and a first electrode and a second electrode are provided facing each other at a predetermined distance from the surface of the substrate. Plasma is generated between the electrodes and the substrate, and both surfaces of the substrate are formed. In a plasma processing apparatus having a configuration capable of performing plasma processing at the same time, circuit means for applying a high-frequency potential is disposed between the first electrode and the second electrode to generate a potential difference between the two plasmas. Plasma comprising means for flowing a high-frequency current between the front and back surfaces of the substrate, and means for forming a state in which the substrate holding mechanism is electrically insulated from the high-frequency circuit except at a contact point with the substrate. Achieved by the processor.

As means for supplying a high frequency current between the front and back surfaces of the substrate, a first high frequency power source for applying a high frequency potential is connected between the first electrode and an arbitrarily determined reference potential, and a first high frequency power source is connected. A second high frequency power source for applying a high frequency potential is connected between the second electrode and the reference potential, and moreover, between the high frequency potential applied to the first electrode and the high frequency potential applied to the second electrode. A phase difference θ may be provided to generate a potential difference between both plasmas, and a high-frequency current may flow between the front and back surfaces of the substrate. By doing so, electric power proportional to sin ² (θ / 2) can be applied to the substrate. That is, the maximum power efficiency applied to the substrate is θ = 180 °,
It is proportional to sin ² (θ / 2) with respect to the phase difference θ.

The plasma processing apparatus of the present invention can be applied to various well-known plasma processing apparatuses such as a sputtering film forming apparatus, a plasma CVD film forming apparatus, a plasma etching apparatus, and a plasma ashing apparatus. Hereinafter, typical device configurations when applied to these devices will be sequentially described.

First, the structure of the sputtering film forming apparatus will be described. This apparatus includes a vacuum container, an exhaust unit for exhausting the vacuum container to a high vacuum, and a unit for supplying a processing gas into the vacuum container. A substrate to be processed placed in a vacuum container, a substrate holding mechanism for holding the substrate to be processed, and a first target electrode provided to face the substrate to be processed and to face each other at predetermined intervals from the surface of the substrate. And a second target electrode and an anode electrode disposed adjacent to each of the target electrodes, and an alternating potential between each target electrode and the anode electrode or each target electrode is set to a negative potential. A double-sided sputtering film-forming apparatus provided with a means for applying a DC potential as described above, wherein circuit means for applying a high-frequency potential is provided between the first target electrode and the second target electrode. A means for flowing a high-frequency current between the front and back surfaces of the substrate by causing a potential difference between the plasmas generated on both sides of the substrate and the high-frequency circuit, and the substrate holding mechanism were electrically insulated except at the contact point with the substrate. And a means for forming a state.

As a preferable configuration example, in the above sputtering film forming apparatus, the first target electrode and the anode electrode facing the first target electrode have a low impedance at the frequency component so that they have the same phase and potential in the frequency component of the high frequency potential. In the same manner, the second target electrode and the anode electrode facing the second target electrode are coupled with low impedance at the frequency component so that they have the same phase and potential in the frequency component of the high frequency potential. is there.

Further, either the first target electrode or the second target electrode may be connected to the ground potential in the frequency component of the high frequency potential with a low impedance.

The apparatus structure is basically the same as that of the above CVD film forming apparatus, and a plasma etching apparatus and a plasma ashing apparatus can be easily constructed by only changing the processing gas supply means, that is, the type of processing gas.

An example of the structure of the plasma CVD film forming apparatus will be described. In this apparatus, a vacuum container, an evacuation unit for exhausting the inside of the vacuum container to a high vacuum, and at least a CVD film forming material gas in the vacuum container. A means for supplying a processing gas, a substrate to be processed placed in a vacuum container, a substrate holding mechanism for holding the substrate to be processed, a substrate to be processed sandwiched, and a predetermined distance from the surface of the substrate to face each other. A double-sided simultaneous plasma CVD film-forming apparatus comprising a first electrode and a second electrode provided as a circuit, wherein circuit means for applying a high-frequency potential is arranged between the first electrode and the second electrode. Set up,
A means for causing a high-frequency current to flow between the front and back surfaces of the substrate by causing a potential difference between both plasmas generated between both surfaces of the substrate to be processed and the opposing electrode, and the substrate holding mechanism and the high-frequency circuit are connected to the substrate. A plasma CVD film forming apparatus having means for forming an electrically insulated state except at the contact point.

Next, a configuration example of the plasma etching apparatus will be described. In this apparatus, a vacuum container, an exhaust unit for exhausting the inside of the vacuum container to a high vacuum, and a processing gas containing at least an etching gas in the vacuum container. And a substrate to be processed placed in a vacuum container, a substrate holding mechanism for holding the substrate to be processed, and a substrate to be processed sandwiched between the substrate surface and a predetermined distance from the substrate surface. A double-sided simultaneous plasma etching apparatus comprising a first electrode and a second electrode, wherein circuit means for applying a high frequency potential is arranged between the first electrode and the second electrode, A means for causing a high-frequency current to flow between the front and back surfaces of the substrate by causing a potential difference between both plasmas generated between both surfaces of the processing substrate and the opposing electrodes, and the substrate holding mechanism and the substrate between the high-frequency circuit. Contact Consisting of a plasma etching apparatus comprising a means for constituting the electrically insulated state is other than a point.

[0022]

Function: One of the plasmas generated on both sides of the substrate is defined as the first plasma, and the other is defined as the second plasma. By the above means, the first plasma and the second plasma are in contact with each other via the substrate, and when a potential difference (bias potential) generated between the two plasmas is generated, a high frequency current (bias) is generated via the capacitance between the front and back surfaces of the substrate. Current) flows.
When the potential of the second plasma becomes positive with respect to the first plasma, electrons from the first plasma are incident on the surface of the substrate facing the first plasma, and ions from the second plasma are emitted from the substrate. Incident on the surface of the second plasma facing the second plasma. On the contrary, when the potential of the first plasma becomes positive with respect to the second plasma, the electrons from the second plasma are incident on the surface of the substrate facing the second plasma and the first plasma is generated. Ions from the plasma impinge on the surface of the substrate facing the first plasma.

At this time, the ions incident on the substrate are accelerated by the electric field between them and collide with the surface of the substrate to give energy to the surface of the film being formed. FIG. 2 shows the relationship between the high-frequency power generated by the high-frequency power source and the energy (indicated by the substrate bias power W) applied to the substrate. As described above, according to the present invention, it is possible to generate an electric field on both front and back surfaces of a substrate to accelerate incident ions without bringing the electrode into contact with the substrate surface. Does not cause evaporation of the film due to the concentration of current, and the accompanying abnormal discharge and defective bias application.

Further, in the present invention, pre-deposition of a conductive film, which was conventionally required to make the substrate a conductor, is unnecessary in the present invention, and even if the substrate surface is an insulator, it is accelerated to the surface. Ions can be injected. If this means is used for forming a magnetic film by, for example, the bias sputtering film forming method, the crystallinity in the film is improved by the ion bombardment, and the coercive force of the magnetic film can be improved.

If it is used in the CVD film forming method, desired thin films can be formed uniformly on both front and back surfaces of the insulating substrate. Furthermore, by using the etching method, the front and back surfaces of the insulating substrate can be etched simultaneously and uniformly.

It is also effective for plasma ashing using well-known oxygen plasma. Further, in this plasma processing method, the energy of accelerated ions incident on the substrate can be used for heating the substrate. Therefore, it can be applied to, for example, substrate heating necessary for improving crystallinity during film formation, and there is an effect that a heating step and a film forming step can be performed in the same process without providing a special heating device. Especially, it is effective in a film forming process on a transparent substrate.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. <Embodiment 1> (1) Device Configuration FIG. 1 is a schematic cross-sectional view of a main part when the present invention is applied to a bias sputtering film forming device for a magnetic disk substrate for a magnetic memory device. As shown in the figure, a first target 5 and a second target 3 made of a film forming material such as Cr or Co-based magnetic alloy are placed facing each other in the vacuum chamber 1, and the respective targets 5 are placed. The first anode electrode 6, the second anode electrode 2, the first deposition-inhibitory plate 7, and the second deposition-inhibition plate 4 are placed so as to surround 3 in an electrically insulated manner. In this case, since the target is made of a conductor, it also serves as a cathode electrode.

The substrate 9 to be film-formed is oriented so that each surface is directed to the respective targets in the middle of the first and second targets 5 and 3 via a holder 21 electrically insulated from the surroundings. Place on. An exhaust device 22 and a processing gas supply system 24 are connected to the vacuum container 1.

Magnetism generating means 11 and 12 are provided on the back surface of the target, respectively, to generate magnetic fields repelling each other with respect to the opposing magnetism generating means, and to form closed magnetic force lines on the respective target surfaces. However, the structure up to this point is the same as that of a known magnetron sputtering apparatus.

The portions described below show the characteristic constitution of the present invention. That is, the first target 5 is connected to the negative side terminal of the first DC power supply 16 via the low-pass filter 15. The first anode electrode 6 is connected to the positive terminal of the DC power supply 16 via a low pass filter 17 and is grounded. The first target 5 and the first anode 6 are connected via a capacitor 18. The high frequency power source 14 is connected to the first target 5 via the matching unit 13 and the capacitor 35, and generates a high frequency potential between the first target 5 and the ground potential.

The second target 3 is the second DC power source 2
0 connected to the negative terminal. Second anode electrode 2
Is connected to the positive terminal of the DC power source 20 and is grounded. The second target 3 and the second anode 2 are connected via a capacitor 19. Capacitors 18, 1
The capacitance C (unit F) of 9 is a value such that C> 0.016 / f with respect to the frequency f (unit Hz) of the high frequency power source 14. That is, the capacitance C of each of these capacitors is set to be a low impedance connection with respect to a high frequency so that a high frequency voltage is not generated between the target electrode and the anode. However, the DC power supplies 16 and 19 are insulated from each other by an insulating material 23 so that a predetermined voltage is applied between the target electrode and the anode.

The low-pass filters 15 and 17 have a cutoff characteristic of 40 dB or more with respect to the frequency f, and the impedance with respect to the frequency f as viewed from the target and anode sides is 10 kΩ or more.

The ring-shaped first deposition-inhibiting plate 7 and the second deposition-inhibiting plate 4, which are provided on the outer periphery of the substrate 9 at a predetermined interval, process gas in the vacuum container so that no discharge occurs between them. Installed at intervals smaller than the Debye length of. The intervals between the first anode 6 and the first deposition preventive plate 7 and between the second anode 2 and the second deposition preventive plate 4 are also made smaller than the Debye length of the processing gas in the vacuum container.

(2) Functions and Effects Next, a sputtering film forming method for forming Cr and Co based magnetic alloy films on both surfaces using the apparatus to be processed 9 as a magnetic disk substrate will be described as a typical example. To do. The vacuum container 1 is evacuated to a high vacuum of 0.0001 Pa or less by the exhaust device 22, and then, for example, Ar is supplied from the processing gas supply system 24.
In a vacuum container so that the pressure is 0.1 to 5 Pa.
The magnetic field generating means 11 and 12 generate magnetic force lines on the first and second targets in directions that repel each other.

First DC power supply 16 and second DC power supply 2
0 and the high frequency power supply 14 supply a predetermined power for a predetermined time. At this time, the first target 5 and the first anode 6
A DC electric field applied from the first DC power source 16 is generated between the above and the processing gas, and the processing gas is ionized to form a plasma (the first plasma 10 is generated). Further, a direct current electric field applied from the second direct current power source 20 is generated between the second target 3 and the second anode 2, and the processing gas is ionized into a plasma state (second plasma 8 is generated). Occurrence). At this time, since a negative voltage is applied to each target, positive ions in the ionized processing gas are accelerated and collide with the target to sputter the target surface, thereby depositing the target material on both surfaces of the substrate.

The first target 5 is connected to the high frequency power source 14 via the capacitor 35 and the matching unit 13, and the high frequency power applied from the high frequency power source 14 causes
The potential fluctuates at the frequency f. At this time, since the first target 5 and the first anode 6 are connected by the capacitor 18 with low impedance to high frequency, the first anode 6 also causes the same potential fluctuation as the first target 5 at the frequency f. At this time, since the first target 5 and the first anode 6 are insulated against direct current, the direct-current potential between them does not change. In addition, the first target 5 and the first
The first DC power supply 16 connected to the anode 6 is not affected by the high frequency power applied from the high frequency power supply by the low pass filters 15 and 17 installed therebetween.
The potentials of the first plasma 10 on the first target 5 and the first anode 6 also change according to the potential changes of the target 5 and the anode 6.

On the other hand, the second anode 2 is grounded, and the second target 3 is connected to the second anode 2 and the capacitor 19 with a low impedance at the frequency f at the frequency f. Does not occur. Therefore, the potential of the second plasma 8 on the second target 3 and the second anode 2 does not change.

First plasma 10 and second plasma 8
Are in contact with each other via the substrate 9, and when a potential difference (bias potential) generated between the two plasmas occurs, a high frequency current (bias current) flows through the capacitance between the front and back surfaces of the substrate 9.
The first and second deposition-inhibitory plates 7, which are also in contact with the plasma,
Although the high-frequency current still flows through 4, the capacitance between the deposition-inhibiting plates becomes lower than the capacitance between the two surfaces of the substrate due to the gap between the two deposition-inhibiting plates, so that most of the high-frequency current flows through the substrate. .

When the potential of the second plasma 8 becomes positive with respect to the first plasma 10, electrons from the first plasma 10 enter the surface of the substrate 9 facing the first target 5, Ions from the second plasma 8 are incident on the surface of the substrate 9 facing the second target 3. On the contrary, when the potential of the first plasma 10 becomes positive with respect to the second plasma 8, electrons from the second plasma 8 enter the surface of the substrate 9 facing the second target 3 and Ions from the first plasma 10 are incident on the surface of the substrate 9 facing the first target 5.

At this time, the ions incident on the substrate 9 are accelerated by the high frequency electric field between the plasma and the substrate 9 and collide with the surface of the substrate 9 to give energy to the surface of the formed film. FIG. 2 shows the relationship between the high-frequency power generated by the high-frequency power source 14 and the energy (substrate bias power W) applied to the substrate 9. As described above, according to the present invention, it is possible to generate an electric field on both surfaces of a substrate to accelerate incident ions without contacting the electrode with the surface of the substrate. The evaporation of the film due to the current concentration in the device, abnormal discharge accompanying it, and bias application failure do not occur.

Further, it is not necessary to pre-form a conductive film which is conventionally required when the substrate is an insulator, and even if the substrate surface is an insulator, accelerated ions can be incident on the surface. Is possible. This ion bombardment improves the crystallinity in the film, and the coercive force of the magnetic film can be improved as shown in FIG. The energy of accelerated Ar ions incident on the substrate is also used for heating the substrate and can contribute to the improvement of film quality.

<Embodiment 2> (1) Device Configuration FIG. 4 is a schematic cross-sectional view of a main part of another embodiment when the present invention is applied to a bias sputtering film forming apparatus for a magnetic disk substrate for a magnetic memory device. Is shown. The difference from the first embodiment will be mainly described, and as shown in the figure, the second anode 2 is mounted while being electrically insulated from the vacuum container.

The second target 3 is connected to the negative terminal of the second DC power source 20 via the low pass filter 33. The second anode electrode 2 has a low-pass filter 3
It is connected to the positive terminal of the DC power source 20 via 4 and is grounded. Second target 3 and second anode 2
Are connected via a capacitor 19.

The substrate holding mechanism 21 is configured to be electrically insulated, grounded, or applied with an arbitrary potential. In a real device,
It is desirable that the device is grounded from the standpoint of assembly and operability of the device.

The high frequency power source 14 is connected to the primary side of the transformer 32. One terminal on the secondary side of the transformer 32 is the first
Connected to the target 5 and the other terminal is the capacitor 3
It is connected to the second target 3 via 6. In addition,
The position of the capacitor 36 may be between the first target 5 and the transformer 32, or may be provided on both of them.

(2) Function and effect By applying electric power from the high frequency power source 14, a high frequency electric field is generated between the first target 5 and the second target 3. Since the first target 5 and the first anode 6 and the second target 3 and the second anode 2 are connected by capacitors 18 and 19 at a low impedance with respect to a high frequency, a high frequency electric field is generated. Does not occur.

The potentials of the first plasma 10 on the first target 5 and the first anode 6 also fluctuate according to the potential fluctuations of these targets and anode. Similarly, the second plasma 8 on the second target 3 and the second anode 2
Also, the potential of the target and the anode fluctuates according to the fluctuation of the potential.

First plasma 10 and second plasma 8
Are in contact with each other via the substrate 9, and a potential difference (bias potential) generated between the two plasmas is generated. Therefore, similarly to the first embodiment, a high frequency bias is generated on the substrate surface, and the same effect is obtained. The feature of this embodiment is that the high frequency potential transformer 32
Since it is given as a relative potential difference between the first target 5 and the second target 3 via, the same high-frequency power can be applied to the substrate surface without being affected by the absolute potential of the substrate 9.

<Embodiment 3> (1) Device Configuration FIG. 5 is a schematic cross-sectional view of a main portion of another embodiment when the present invention is applied to a bias sputtering film forming apparatus for a magnetic disk substrate for a magnetic storage device. Is shown. The difference in structure from the second embodiment will be mainly described. As shown in the drawing, both the first anode 6 and the second anode 2 are grounded and are at ground potential, and are connected between the target and the anode. The difference is that the capacitor that has been used is removed and the substrate holding mechanism 21 is electrically insulated from the surroundings.

(2) Function and Effect In the above-described first and second embodiments, the high frequency current is the first target 5 and the anode 6 and the second target 3 and the anode 2.
Although only the substrate 9 flows through the plasma between the first target 5, the first plasma 10, the first plasma 10, and the first high-frequency current in addition to the circuit described above in which the high-frequency current flows.
Since the circuit of the path of the anode 6, the ground wiring, the second anode 2, the second plasma 8 and the second target 3 can be formed, the ratio of the applied high frequency power used for the bias effect to the substrate decreases, The amount will be used for sputtering the target. In this embodiment, there is a disadvantage that the utilization efficiency of the high frequency power for the substrate bias is lowered,
The feature is that it is not necessary to insulate the anode, the electrode structure is simple, and it can be easily applied to conventional electrodes.

<Embodiment 4> (1) Device Configuration FIG. 6 is a schematic cross-sectional view of a main part of another embodiment when the present invention is applied to a bias sputtering film forming apparatus for a magnetic disk substrate for a magnetic memory device. Is shown. The difference in configuration from the third embodiment will be mainly described. As shown in the figure, the high frequency signal generator 2 is used instead of the high frequency power supply 14 and the transformer 32.
The high-frequency signal of the low electric potential level generated from 5 generates high-frequency electric power between the first electric power amplifier 27 and the ground electric potential,
The matching device 13 is connected to the first target 5 for impedance matching.

On the other hand, after the phase adjuster 26 shifts the phase of the high frequency signal of the same low potential level, the second power amplifier 28 generates high frequency power between the high potential signal and the ground potential, and the matching unit 29 performs impedance matching. Tori's second target 3
The difference is that it is connected to.

(2) Operation and Effect The high-frequency current flowing through the first target 5 passes through the first plasma 10 to the first anode 6, and the high-frequency current flows from the first plasma 10 to the substrate 9 and the second. Plasma 8
Flow through to the second anode 2 through.
The high-frequency current passing through the second target 3 takes a symmetrical path, passes through the second plasma 8, and passes through the second anode 2
Flowing through the second plasma 8 to the first anode 6 through the substrate 9 and the first plasma 10. Therefore, when the phase difference of the phase adjuster 26 is set to 0, the currents passing through the substrate 9 cancel each other out, and the alternating current no longer flows through the substrate, so that the bias power is not applied. Conversely, when the phase difference generated by the phase adjuster 26 reaches 180 °, the high frequency current passing through the substrate 9 becomes maximum. When the phase difference is 180 °, the high frequency potentials applied to the first and second targets 5 and 3 have opposite phases,
The high frequency potential is applied between the first and second targets, and the same effect as that of the third embodiment can be obtained.

<Embodiment 5> (1) Device Configuration FIG. 7 is a schematic cross-sectional view of a main part of another embodiment when the present invention is applied to a bias sputtering film forming apparatus for a magnetic disk substrate for a magnetic memory device. Is shown. The difference from the fourth embodiment will be mainly described, except that the DC power supplies 16 and 20 and the low-pass filters 15 and 33 are removed as shown in the figure.

(2) Operation and effect In this embodiment, the high-frequency currents flowing through the first and second targets 5 and 3 take the same route as in Embodiment 4, but no DC electric field is applied by the DC power source. The sputtering effect on the target is due to only the high frequency power applied from the high frequency power source and applied between the first target 5 and the first anode 6 or between the second target 3 and the second anode 2. is there. In this case, the high-frequency power amplifiers 27 and 28 need to generate the power necessary for sputtering the target, but since the DC power supply and the low-pass filter are not necessary, the device configuration is simplified and the device cost can be reduced. The bias power to the substrate is adjusted by the phase adjuster 26 as in the fourth embodiment.

Although the above-mentioned examples show the bias sputtering film forming method and the film forming apparatus, the following Examples 6 to 8 show the plasma CVD film forming method and the film forming apparatus.

Sixth Embodiment (1) Device Configuration FIG. 8 is a schematic cross-sectional view of a main part of a CVD electrode when the present invention is applied to a plasma CVD film forming device. As shown, the first electrode 30 and the second electrode 3 are provided in the vacuum container 1.
The first and the first deposition preventive plates 7 and the second deposition preventive plate 4 are made of the insulating material 23.
And are electrically insulated from each other via. The substrate 9 to be film-formed is placed in the middle of the first electrode 30 and the second electrode 31 with the substrate holding mechanism 21 electrically insulated from the surroundings so that each surface faces the respective electrodes. . An exhaust device 22 and a processing gas supply system 24 are connected to the vacuum container 1.

The high frequency power source 14 is connected to the first electrode 30 through the matching unit 13 and generates a high frequency potential between itself and the ground potential. The second electrode 31 is grounded. The first deposition-inhibiting plate 7 and the second deposition-inhibiting plate 4 are installed at intervals smaller than the Debye length of the processing gas in the vacuum container 1 so that no discharge occurs between them. First electrode 30 and first
Similarly, the distance between the deposition preventing plate 7 and the second electrode 31 and the second deposition preventing plate 4 is also made smaller than the Debye length of the processing gas in the vacuum container 1.

(2) Functions and Effects Next, a specific example of a film forming method using this film forming apparatus will be described together with its functions. The substrate 9 is a magnetic disk substrate for a magnetic storage device in which magnetic films are formed on both sides in Example 1, and a carbon protective film is formed on both sides of the substrate by plasma CVD.

The vacuum container 1 is set to 0.00 by the exhaust device 22.
After being evacuated to a high vacuum of 1 Pa or less, the processing gas supply system 2
4, methane, for example, is supplied as a carbon raw material so as to have a pressure of 1 to 30 Pa in a vacuum container.

A predetermined power is supplied from the high frequency power supply 14 for a predetermined time. The first electrode 30 is connected to the high frequency power source 14 via the matching unit 13, and the high frequency power applied from the high frequency power source 14 causes a potential variation at a frequency f. The substrate 9 and the first and second plasma shields (first,
The second deposition prevention plates 7, 4) are placed symmetrically between the first and second electrodes, and due to the symmetry between them, the same electric field on the first electrode and on the second electrode. Is generated and the process gas is ionized.

First plasma 10 and second plasma 8
Are in contact with each other via the substrate 9, and a high-frequency current flows through the capacitance between the front and back surfaces of the substrate. High-frequency current also flows through the first and second deposition-inhibitory plates 7 and 4 that are also in contact with the plasma, but due to the gap between these two shields,
Since the capacitance between the shields is lower than the capacitance between both sides of the substrate 9, most of the high frequency current flows through the substrate 9.

When the potential of the second plasma 8 becomes positive with respect to the first plasma 10, the first plasma 10
From the above, electrons enter the surface of the substrate 9 facing the first electrode 30, and ions from the second plasma 8 enter the surface of the substrate 9 facing the second electrode 31. On the contrary, the first plasma 10
When the potential of the second plasma 8 becomes positive with respect to the second plasma 8, electrons are emitted from the second plasma 8 to the second electrode 3 of the substrate 9.
1, and the ions from the first plasma 10 are incident on the surface of the substrate 9 facing the first electrode 30.
At this time, the ions incident on the substrate 9 are generated by the plasma and the substrate 9
Is accelerated by a high frequency electric field between them and collides with the surface of the substrate to decompose methane molecules to deposit a carbon film having an amorphous crystal structure.

As described above, according to the present invention, it is possible to generate an electric field on both surfaces of the substrate to cause accelerated ion injection without contacting the electrode with the surface of the substrate as in the conventional case. As in the past, evaporation of the film due to current concentration at the contact point of the electrode on the substrate surface and accompanying abnormal discharge,
Defects in film formation do not occur. In addition, it is not necessary to previously form a conductive film, which is conventionally required when the substrate is an insulator, and a carbon film can be formed on the surface of the substrate even if it is an insulator.

<Embodiment 7> (1) Device Configuration FIG. 9 shows a schematic cross-sectional view of a main part of a CVD electrode according to another embodiment when the present invention is applied to a plasma CVD film forming device. The difference from the sixth embodiment will be mainly described. Even if the substrate holding mechanism 21 is electrically insulated, grounded, or applied with an arbitrary potential, as shown in the figure. It has a good structure. In consideration of workability when the substrate is transported, the device configuration is easier when the substrate holding mechanism 21 is grounded.

The high frequency power source 14 is connected to the primary side of the transformer 32. One terminal on the secondary side of the transformer is connected to the first electrode 30, and the other terminal is connected to the second electrode 31. Also in this case, the other terminal is connected to the second target 3 via the capacitor 36 as in the second embodiment. The position of the condenser 36 is set to the first target 5
Between the transformer 32 and the transformer 32.

(2) Operation and effect By applying electric power from the high frequency power source 14, the first electrode 3
A high-frequency electric field is generated between 0 and the second electrode 31. The potential of the first plasma 10 on the first electrode 30 also changes according to the change in the potential of this electrode. The potential of the second plasma 8 on the second electrode 31 also varies according to the potential variation of this electrode.

First plasma 10 and second plasma 8
Are in contact with each other via the substrate 9, and a potential difference (bias potential) generated between the two plasmas is generated. Therefore, similarly to the sixth embodiment, a high frequency bias is generated on the surface of the substrate 9 and the same effect is obtained. It was possible to form a uniform carbon protective film. In this embodiment, the high-frequency potential is given as a relative potential difference between the first electrode 30 and the second electrode 31 via the transformer 32, and thus the high-frequency potential is applied to the substrate surface without being affected by the absolute potential of the substrate. The feature is that high frequency power can be applied.

<Embodiment 8> (1) Device Configuration FIG. 10 shows a schematic cross-sectional view of a main part of a CVD electrode according to still another embodiment when the present invention is applied to a plasma CVD film forming device. . Explaining mainly the difference in configuration from the seventh embodiment, as shown in the drawing, the columns 36 and 37 are installed at the centers of the first electrode 30 and the second electrode 31,
Mask plates 38 and 39 having substantially the same diameter as the spindle hole at the center of the substrate are attached to the tip thereof. The interval between these mask plates facing each other is set smaller than the Debye length of the processing gas so that plasma is not generated therebetween.

(2) Operation and effect The substrate 9 having holes like the magnetic disk substrate is used in the sixth embodiment.
In the case of using for, the electric charge (mainly electrons) in the plasma can freely flow through the hole of the substrate, so that the impedance of that part is lowered, the high frequency current is concentrated, and the plasma density can be offset in the radial direction of the substrate. A distribution is generated in the ion current density incident on the substrate surface. As a result, the film thickness to be formed also has a distribution in which the periphery of the hole is thick, which is not preferable in practice. However, according to the present embodiment, by closing the holes of the substrate 9 with the mask plates 38 and 39, the high frequency current concentration is eliminated, a uniform plasma density distribution is obtained, and the film thickness is uniform.

FIG. 11 shows another means for achieving uniform ion injection onto a perforated substrate for the same purpose as in Example 8. FIG. 11 (a) is held by the substrate holding mechanism 21. Sectional drawing which showed the relationship between the board | substrate 9 and the ring-shaped attachment prevention plates 4 and 7 provided in the board | substrate periphery, and the same figure (b) is the side view.

The distance between the substrate 9 and the deposition-preventing plates 4 and 7 in Examples 1 to 7 described above is set to be wider than the Debye length of the processing gas by d.
So that charged particles can pass through them. Practically, it is preferable that the area of the distance d is equal to or less than twice the area of the hole 40. As a result, the high-frequency current concentrated only in the hole 40 at the center of the substrate is flown to the periphery of the substrate, and the plasma density on the substrate is made uniform accordingly.

<Embodiment 9> Embodiments 6 to 8 show examples of manufacturing a magnetic disk in which a carbon protective film is formed on a magnetic film by using methane as a processing gas. Here, the processing gas is Ar. An example in which plasma etching processing is performed on both surfaces of the substrate by switching to an inert gas such as the above will be described.

The sample substrate is a Si wafer on which a semiconductor element is formed in advance, and a wiring pattern is formed in multiple layers on the element via an interlayer insulating film. First, in the sputtering film forming apparatus of Example 1, an aluminum thin film for conductor wiring is formed by using aluminum as a target electrode. A resist mask pattern to which a wiring pattern has been transferred is formed thereon by a known method. Using the wafer on which this resist mask pattern is formed as the substrate 9 to be processed, the CVD of Example 6 is performed.
Ar gas was introduced instead of the film forming source gas (methane),
An aluminum wiring pattern is formed by tailoring this apparatus to a plasma etching apparatus and performing plasma treatment.

The etching rate can be further increased by using, for example, a halogen-based etching gas as a gas having a corrosiveness with respect to the surface composition of the substrate to be processed together with the Ar gas. As a result, a high-definition wiring pattern could be formed. Further, if the etching condition is a low temperature below room temperature, it becomes easier to form a finer wiring pattern, which can contribute to the manufacture of a high-density LSI. This plasma etching method is also effective when texturing the surface of the magnetic disk substrate.

<Embodiment 10> The wafer substrate on which the wiring pattern is formed in Embodiment 9 is used as the substrate 9 to be processed, and the processing gas is A
As a mixed system of r gas and oxygen gas, the resist mask pattern left on the substrate was removed by plasma ashing treatment. The configuration of the processing apparatus used was the same as that in Example 9, but the type of processing gas was changed. As a result, the resist covering the aluminum wiring pattern was completely removed.

As described above, the plasma processing method and the processing apparatus have been mainly described with respect to the film formation, the etching and the ashing, but it goes without saying that the present invention can be applied to any known plasma processing.

[0078]

As described above in detail, according to the present invention, the intended purpose can be achieved. That is, according to the present invention, when plasma processing is performed on both surfaces of the substrate, it is possible to generate a high frequency electric field on both surfaces of the substrate and accelerate incident ions without contacting the electrodes with the substrate surface. Even a body substrate and a substrate whose surface is covered with an insulator have an effect that accelerated ions can be incident on the surface.

Further, unlike the prior art, there is an effect that stable processing can be performed without causing evaporation of the film due to current concentration at the contact point of the electrode on the substrate surface and abnormal discharge accompanying it, or bias application failure. is there.

Further, there is no need for means for contacting the electrode with the surface of the substrate, which is conventionally required, and there is an effect that the structure of the processing apparatus and the processing process can be simplified. When this means is used for the bias sputtering film forming method, even when the film is formed on the insulating substrate, the film quality can be improved such that the crystallinity in the film is improved by the ion bombardment to the film surface.

If plasma CVD is used, a desired film can be simultaneously formed on both the front and back surfaces of the insulating substrate regardless of a conductive film or an insulating film. Further, by using for plasma etching, it is possible to simultaneously perform etching treatment on both front and back surfaces of the insulating substrate. Further, by using it for heating the substrate, it is possible to supply heat even to a transparent insulator substrate which is particularly difficult to heat with a lamp.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part configuration of a bias sputtering film forming apparatus according to an embodiment (Embodiment 1) of the present invention.

FIG. 2 is a graph showing the relationship between the high frequency power applied by the bias sputtering film forming apparatus and the bias power incident on the substrate.

FIG. 3 is a graph showing the relationship between the high-frequency power applied by the bias sputtering film forming apparatus and the magnetic characteristics (coercive force) of the formed magnetic film.

FIG. 4 is a sectional view of the essential part of a bias sputtering film forming apparatus according to another embodiment (embodiment 2).

FIG. 5 is a cross-sectional view of a main part configuration of a bias sputtering film forming apparatus according to another embodiment (Example 3).

FIG. 6 is a cross-sectional view of the main part of a bias sputtering film forming apparatus according to another embodiment (Example 4) of the same.

FIG. 7 is a cross-sectional view of the essential parts of a bias sputtering film forming apparatus according to another embodiment (embodiment 5).

FIG. 8 is a sectional view of a main part of a CVD film forming apparatus according to another embodiment (Example 6) of the same.

FIG. 9 is a cross-sectional view of the essential part of a CVD film forming apparatus according to another embodiment (Embodiment 7) of the same.

FIG. 10 is a CVD according to another example (Example 9).
FIG. 3 is a cross-sectional view of the essential parts of the film forming apparatus.

FIG. 11 is an explanatory diagram showing a relationship between a substrate and a deposition preventive plate around the substrate according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vacuum container, 2 ... 2nd anode electrode, 3 ... 2nd target electrode, 4 ... 2nd deposition preventive plate, 5 ... 1st target electrode, 6 ... 1st anode electrode, 7 ... 1st Protection plate, 8 ... Second plasma, 9 ... Substrate, 10 ... First plasma, 11, 12 ... Magnetic generation means, 13, 29 ... Matching device, 14 ... High frequency power supply, 15, 17 ... Low pass filter, 16, 20 ... DC power supply, 17 ... Low pass filter, 18, 19 ... Capacitor, 21 ... Substrate holding mechanism, 22 ... Exhaust device, 23 ... Insulating material, 24 ... Processing gas supply system, 25 ... High frequency signal generator, 26 ... Phase adjuster, 27, 28 ... Power amplifier, 30 ... First electrode, 31 ... Second electrode, 32 ... Transformer, 33, 34 ... Low pass filter, 35 ... Capacitor, 36, 37 ... Strut, 38, 39 … Mask plate, 40 …hole.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norimasa Nishimura 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Inside the Hitachi, Ltd. Institute of Industrial Science (72) Inventor Hiroyuki Kataoka 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi, Ltd., Production Technology Research Laboratory (72) Inventor, Hiroshi Inaba, 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture, Ltd. Production Technology Research Laboratory, Hitachi, Ltd. (72) Inventor, Katsuo Abe, Kanafuzu, Odawara, Kanagawa 2880 Hitachi Storage Systems Division

Claims (10)

[Claims] 1. A method of generating plasma on both sides of a substrate to be processed placed in a vacuum container to perform plasma treatment on both sides simultaneously, wherein high frequency energy is applied to at least one of the plasmas. A plasma processing method in which a high-frequency current is caused to flow between the front and back surfaces of the substrate by causing a potential difference therebetween. 2. A plasma is simultaneously generated on both surfaces of the substrate by simultaneously generating plasma between the substrate to be processed placed in the vacuum container and the electrodes provided on both surfaces of the substrate and facing each other at a predetermined distance. A high-frequency energy is applied to one of the plasmas and not applied to the other plasma to generate a potential difference between the two plasmas so as to generate a potential difference between the front and back surfaces of the substrate. A plasma processing method in which a high-frequency current is applied to the substrate. 3. A plasma is generated between both surfaces of the substrate at the same time by generating plasma between a substrate to be processed placed in a vacuum container and electrodes facing each other with a predetermined distance from both sides of the substrate. In this method, high-frequency energy having a different phase is applied to both plasmas to generate a potential difference between the two plasmas so that a high-frequency current flows between the front and back surfaces of the substrate. A plasma processing method comprising. 4. A vacuum vessel, an evacuation means for evacuating the inside of the vacuum vessel to a high vacuum, a means for supplying a processing gas into the vacuum vessel, a substrate to be processed placed in the vacuum vessel, and a substrate to be processed. A substrate holding mechanism for holding the substrate to be processed and a first electrode and a second electrode sandwiching the substrate to be processed and facing each other at a predetermined distance from the surface of the substrate are provided. In a plasma processing apparatus having a structure capable of simultaneously performing plasma processing on both surfaces of a substrate by generating plasma between them, circuit means for applying a high frequency potential is provided between the first electrode and the second electrode. A means for causing a potential difference between both plasmas to flow a high-frequency current between the front and back surfaces of the substrate, and the substrate holding mechanism are electrically insulated from the high-frequency circuit except at a contact point with the substrate. And means for configuring Plasma processing apparatus. 5. A vacuum container, an evacuation means for evacuating the inside of the vacuum container to a high vacuum, a means for supplying a processing gas into the vacuum container, a substrate to be processed placed in the vacuum container, and a substrate to be processed. A substrate holding mechanism for holding the substrate to be processed and a first electrode and a second electrode sandwiching the substrate to be processed and facing each other at a predetermined distance from the surface of the substrate are provided. A plasma processing apparatus having a structure capable of simultaneously performing plasma processing on both surfaces of a substrate by generating plasma between them, and a first high-frequency power source for applying a high-frequency potential between the first electrode and an arbitrarily determined reference potential. And a second high frequency power source for applying a high frequency potential between the second electrode and the reference potential, and a high frequency potential applied to the first electrode and the second electrode. Between the applied high frequency potential The plasma processing apparatus formed by disposing a means for flowing a high-frequency current between the front and back surfaces of the substrate allowed a potential difference in between both the plasma provided retardation. 6. A vacuum vessel, an evacuation means for evacuating the inside of the vacuum vessel to a high vacuum, a means for supplying a processing gas into the vacuum vessel, a substrate to be processed placed in the vacuum vessel, and a substrate to be processed. A substrate holding mechanism that holds the substrate to be processed and a first target electrode and a second target electrode that are provided to face the substrate to be processed and that are opposed to each other at a predetermined distance from the surface of the substrate are adjacent to the target electrodes. And a means for applying an alternating-current potential or a direct-current potential that makes each target electrode a negative potential between each target electrode and the anode electrode. In the film device, circuit means for applying a high frequency potential is provided between the first target electrode and the second target electrode to generate a potential difference between plasmas generated on both sides of the substrate, Sputtering comprising means for passing a high frequency current between the front and back surfaces of the substrate, and means for forming a state in which the substrate holding mechanism is electrically insulated from the high frequency circuit except at a contact point with the substrate. Deposition apparatus. 7. The sputtering film forming apparatus according to claim 6, wherein the first target electrode and the anode electrode facing the first target electrode have the same phase and the same potential in the frequency component of the high frequency potential and have a low impedance in the frequency component. Similarly, the second target electrode and the anode electrode facing the second target electrode are connected by low impedance with the frequency component so that they have the same phase and potential in the frequency component of the high frequency potential. apparatus. 8. The sputtering film forming apparatus according to claim 7, wherein either the first target electrode or the second target electrode is coupled to the ground potential at a low impedance in the frequency component of the high frequency potential. A sputtering film forming apparatus configured as described above. 9. A vacuum vessel, an evacuation means for evacuating the inside of the vacuum vessel to a high vacuum, a means for supplying a processing gas containing at least a CVD film forming raw material gas into the vacuum vessel, and mounting in the vacuum vessel. A substrate to be processed, a substrate holding mechanism for holding the substrate to be processed, a first electrode and a second electrode sandwiching the substrate to be processed and facing each other at predetermined intervals from the surface of the substrate. In the double-sided simultaneous plasma CVD film forming apparatus, circuit means for applying a high-frequency potential is provided between the first electrode and the second electrode, and the circuit means is provided between both surfaces of the substrate to be processed and the opposing electrode. A state in which a potential difference is generated between the generated plasmas so that a high-frequency current flows between the front and back surfaces of the substrate and the substrate holding mechanism is electrically insulated from the high-frequency circuit except at a contact point with the substrate. And means for configuring Zuma CVD film-forming apparatus. 10. A vacuum vessel, an evacuation means for evacuating the vacuum vessel to a high vacuum, a means for supplying a processing gas containing at least an etching gas into the vacuum vessel, and an object placed in the vacuum vessel. A first electrode and a second substrate that are provided to face the substrate to be processed, a substrate holding mechanism that holds the substrate to be processed, and a substrate to be processed, which are spaced apart from the substrate surface by a predetermined distance.
In the double-sided simultaneous plasma etching apparatus including the electrodes, the circuit means for applying a high frequency potential is arranged between the first electrode and the second electrode, and the electrodes facing both sides of the substrate to be processed are provided. Between the front and back surfaces of the substrate by causing a potential difference between the two plasmas generated between the substrate and the high frequency circuit, and the substrate holding mechanism is electrically insulated at points other than the contact point with the substrate. Plasma etching apparatus comprising: a means for forming an opened state.