JPH0660394B2 - Plasma processing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in an apparatus for forming a thin film by plasma treatment and etching, and particularly, to deposit a film forming material on a fine hole on a substrate surface of a semiconductor device or the like. Deposition is easy,
Alternatively, the present invention relates to a plasma processing apparatus capable of continuously processing a thin film circuit on the surface of a substrate at a high speed and uniformly and suitable for mass production.

[Conventional technology]

As a high-speed thin film forming apparatus by sputtering, which is a typical method for forming a film (meaning that a thin film is formed, the same applies hereinafter), as described in JP-A-61-87868, a substrate having a cusp magnetic field is used as a substrate. Bias sputtering that applies a negative voltage to the electrode to collide the thin film surface deposited and deposited on the substrate surface with ions to re-sputter the film surface or collide with the deposited particles and give energy to improve the migration property of the deposited particles. There is a law. In the above technique, a high density plasma is confined on the substrate wafer by the cusp magnetic field, so that a large number of ions can be made to collide with the substrate surface.
It is intended to improve re-sputtering and migration performance of the film formation surface.

Further, as a sputter etching apparatus for circuit processing, as described in JP-A-60-74436, plasma generated by high frequency power applied to an etching electrode is confined on a substrate using a magnet, and plasma on the substrate is confined. There is a method of increasing the density of plasma by preventing the diffusion of hydrogen. According to this, the voltage generated at the substrate-side electrode can be lowered, and the damage to the substrate can be reduced and the etching rate can be improved.

[Problems to be solved by the invention]

The above-mentioned conventional technique of sputtering is excellent in film forming speed, target utilization efficiency, improvement of the amount of ions flowing into the substrate, etc., but since the target electrode and the substrate electrode are arranged facing each other in the cusp magnetic field, The magnetic force lines formed by the magnetic device on the substrate side cross the substrate by concentrating the magnetic force lines emitted from the magnetic device on the target side to the front surface of the target and then focusing on the center of the substrate electrode. Charged particles in plasma, especially electrons with small mass, perform cyclotron motion along magnetic field lines in a magnetic field. Therefore, the electrons in the plasma are concentrated and incident on the center of the substrate along the lines of magnetic force generated by the magnetic device on the substrate side. Similar to this is the journal
Of Applied Physics Volume 34.
4. (1963) Pages 760 to 768 (Journal of
Applied Physics Vol. 34 No.4 (1963) pp760
~ 768). According to the above-mentioned document, when the substrate is used as an anode to form a film by sputtering, the current is concentrated in the central portion of the substrate, and the temperature of this portion is abnormally increased. This causes problems such as melting at the center and non-uniformity of film quality especially when a low melting point material such as Al is formed into a film. Further, even in the bias sputtering method in which a negative voltage is applied to the substrate electrode and the ions are made incident on the substrate surface, the incident ion density is also increased in the central portion due to the electrons concentrated in the central portion on the substrate electrode, and the bias power is not uniform. In addition to the problem of abnormal temperature rise in the central part, the migration performance depending on the bias power differs depending on the position, and there is a problem in film formation reliability. Further, in the conventional technique of the above-mentioned sputter etching apparatus, the uniformity of the plasma density on the substrate is insufficient, and it has been desired to further equalize the etching rate in the substrate. Furthermore,
Mass production of substrates has not been fully studied, and the development of an apparatus that can continuously process the substrate, such as automatically sending out the processed substrate and supplying a new substrate to the plasma processing unit, has been developed. I was waiting.

An object of the present invention is to prevent high-energy electrons from being concentratedly incident on the central portion of the substrate, and also to make the ion incidence on the substrate to be processed uniform even in plasma processing such as bias sputtering and sputter etching. A continuous sputtering device that has a uniform film quality and has sufficient migration performance over the entire surface of the substrate to be processed and that enables continuous processing, and for etching, performs high-speed sputter etching processing uniformly on the entire surface of the substrate to be processed. It is to provide a sputter etching apparatus that enables continuous processing.

[Means for solving problems]

An object of the present invention is to provide a first electrode facing a processing surface of a substrate to be processed with a predetermined gap, a second electrode on which the substrate to be processed is mounted, and the first and second electrodes. In the plasma processing apparatus, the first electrode-side magnetic device that generates a magnetic field between the first electrode-side magnetic device and the second electrode-side magnetic device cooperates to form a cusp magnetic field between the first and second electrodes. The third magnetic device for generating a magnetic force line in a direction opposite to that of the second electrode side magnetic device so that the magnetic force line generated by the second electrode side magnetic device does not cross at least the central portion of the substrate to be processed. Movement for moving the second electrode between the inside of the electrode side magnetic device and the transfer position where the substrate to be processed is placed on the second electrode and the processing position where plasma processing is performed on the substrate to be processed. Means and the substrate to be processed at the transfer position. Become comprises a conveying means for feeding,
This is achieved by a plasma processing apparatus having a structure that enables continuous plasma processing.

Further features of the present invention are listed below.

(1) On the surface of the substrate to be processed on the second electrode. Providing bias voltage applying means for generating a predetermined negative bias voltage.

(2) The second electrode is provided with a cooling unit that penetrates the inside of the second electrode and introduces a fluid for cooling the substrate to be processed between the substrate to be processed and the second electrode.

(3) Applying high frequency power to the second electrode.

(4) A target made of a desired film forming material is placed on the first electrode, and the target is sputtered to form a thin film made of the desired film forming material on the substrate to be processed. What I did.

(5) An elevator for moving the second electrode, which is provided outside the vacuum container and includes an electrode cylinder that is movable up and down. Further, the second electrode moves the substrate to be processed up and down. A mechanism is provided.

[Action]

The first electrode and the second electrode are arranged so as to face each other, and a magnetic device which is provided on the first electrode side and the second electrode side and generates magnetic lines of force opposite to each other is provided between the two electrodes. A cusp magnetic field is formed, and high-density plasma is confined between the two electrodes by these magnetic devices, and the magnetic lines of force of the magnetic device on the second electrode side do not cross the central portion of the substrate to be processed, and the magnetic field lines are formed around the substrate. By arranging a third magnetic device that generates a magnetic force line in a direction opposite to that of the magnetic device on the second electrode side, which has a function of being guided, inside the magnetic device on the second electrode side, The magnetic lines of force of the electrode-side magnetic device are generated by the first magnetic lines of force of the second electrode-side magnetic device.
Magnetic field lines on the first electrode that are pressed onto the first electrode are formed along the surface of the first electrode and confine a high-density plasma on the first electrode over a wide area. On the other hand, the magnetic force lines of the magnetic device on the side of the second electrode that pushes the magnetic force lines of the magnetic device on the side of the first electrode into the first electrode are the action of the opposite magnetic force lines generated from the third magnetic device. Thus, the electrons in the plasma confined on the first electrode do not concentrate on the substrate to be processed because they are guided to the periphery of the substrate without traversing the central part of the substrate to be processed. Along with this, the amount of ions in the plasma incident on the substrate is made uniform, and the migration property of the film formation surface during bias sputtering or the etching rate during sputter etching is achieved.

Further, the moving means for moving the second electrode and the carrying means for the substrate to be processed are interlocked to feed the substrate to be processed to a position for plasma processing, and after the plasma processing here, the carrying means is carried again. The plasma treatment can be continuously performed by moving the substrate to the outside of the plasma treatment position and repeating this cycle sequentially.

〔Example〕

 Hereinafter, specific examples of the present invention will be described in detail with reference to Examples.

Example 1. This example relates to a sputtering device that forms a thin film,
The configuration of the device will be described with reference to FIG.

A gas valve 2, a gas introduction pipe 3, and a vacuum exhaust unit 4 for introducing a processing gas are connected to the vacuum container 1. A target electrode 5 corresponding to the first electrode is attached to the upper surface of the vacuum container 1. A target 6 made of a film forming material is attached to the vacuum side of the target electrode 5, and a target coil 7 for generating a magnetic field corresponding to the first electrode side magnetic device is attached to the atmosphere side.

On the side facing the target electrode 5, there is a substrate electrode 9 corresponding to a second electrode on which a substrate 8 corresponding to the substrate to be processed is placed. The substrate electrode 9 is indicated by a solid line in FIG. It is possible to move to the transport position shown and the processing position shown by the alternate long and short dash line. This substrate electrode 9 has an elevator 11 that moves the substrate 8 up and down, and further, a cooling gas as a cooling means that penetrates the elevator 11 and introduces a fluid for cooling the substrate 8 between the substrate electrode 9 and the substrate 8. An introduction pipe 12 is provided.

In addition, the substrate electrode 9 has a built-in substrate inside coil 13 that constitutes the third magnetic device, and is located around the substrate electrode 9 when the substrate electrode 9 is at the processing position, and corresponds to the second electrode side magnetic device. Outer coil 14 and target coil 7
And cooperate to form a cusp field.

Further, in FIG. 1, a bias mechanism 15 for applying a DC bias voltage to the surface of the substrate 8 at the processing position is attached to the right of the substrate electrode 9 at the processing position. The bias mechanism 15 includes a contactor 16 that contacts the substrate 8, a bias body 17 to which the contactor 16 is attached, a roller 18 attached to the bias body 17, a guide plate 20 having a groove 19 in which the roller 18 runs, and a bias body 17. Is composed of a spring 21 that always pulls to the right and a bias cylinder 22 that pushes the bias body 17 diagonally downward to the left.

The substrate 8 is a gate valve 2 provided on the side wall of the vacuum container 1.
It is carried in and out from 3, 24, but movement in the vacuum chamber is
It is carried out by the transport means 29, 30. A typical structure of this conveying means is, for example, a pulley 301 and a belt 302, and the shaft of the pulley 301 is connected to a rotation driving means (not shown) such as a motor to rotate, thereby causing the belt to move on the belt. It is a mechanism for transporting the placed substrate to be processed.

The present embodiment having the above configuration operates as follows.

The substrate 8 introduced from the gate valve 23 of the vacuum container 1 is
The transfer means 29 transfers the substrate electrode 9 to the center thereof. Next, the elevator 11 moves up, and after the substrate 8 is transferred from the carrier means 29 to the elevator 11, the carrier means 29 is retracted, the elevator 11 is lowered, and the substrate 8 is placed on the substrate electrode 9.

Next, the electrode cylinder 10 is operated to raise the substrate electrode 9 to the processing position shown by the chain line in the figure. Next, after closing the gate valve 23, the evacuation speed by the vacuum evacuation means 4 and the amount of gas introduced through the gas introduction pipe 3 are adjusted, and the inside of the vacuum container is kept at a predetermined pressure, typically Keep on. Next, the target coil 7 and the substrate inner coil 13 are excited so as to generate a magnetic field in the same direction, and the substrate outer coil 14 is excited so as to generate a magnetic field in the opposite direction to the two coils, thereby generating magnetic force lines 25 and 26 as shown in FIG. . That is, the target coil 7 and the substrate outer coil 14 are excited so as to have mutually opposite magnetic poles, that is, a so-called Kapus magnetic field. Here, the board inner coil 13 is excited so as to have a magnetic pole opposite to that of the board outer coil 14. As a result, the point cup formed by the target coil 7 and the substrate outer coil 14 and passing through the central portion of the substrate 8 of the coupled magnetic field spreads due to the magnetic field strength of the substrate inner coil 13 and becomes a predetermined value. It is larger than the diameter. As a result, the magnetic force lines become magnetic force lines 25 and 26 as shown in FIG. Due to this action, the magnetic force lines do not cross the central portion of the substrate 8, so that electrons that move along the magnetic force lines while performing cyclotron movement do not enter the substrate 8, and the local rise in substrate temperature and electron damage to the film occur. Can be prevented.

Next, sputtering power is applied to the target electrode 5 to generate plasma 28 between the target electrode 5 and the substrate electrode 9, and the surface of the target 6 made of, for example, a conductive metal is sputtered to deposit the target material on the substrate 8. To reach.
After forming a thin film having a predetermined thickness on the substrate 8, the bias cylinder 22 is operated to move the roller 18 along the groove 19 of the guide plate 20, and the bias body having the roller 18 attached thereto.
17 is moved diagonally downward to the left in FIG. 1 to bring the contactor 16 into contact with the substrate 8 so that the bias power source (not shown) is connected to the bias body.
Bias sputtering is performed by applying a DC bias voltage to the surface of the substrate 8 via the contactor 16.

When inducing a high-frequency self-bias voltage on the surface of the substrate 8, high-frequency power may be applied to the substrate electrode 9 mounting surface of the substrate 8, and the bias mechanism 15 is not necessary.

The magnetic field lines 25 on the target 6 are widely pressed onto the surface of the target 6 by the magnetic device 14 on the substrate 8 side, which generates magnetic field lines in the opposite direction. The utilization rate of will both improve. In addition, the magnetic field lines 26 created by the magnetic device 14 on the substrate side should not cross the central portion of the substrate 8.
By being guided to the periphery of the substrate 8, the ions in the plasma 28 are incident on the substrate 8 at a high density and evenly.
Uniformly promotes migration on the surface of the thin film material deposited. During bias sputtering, 100 to 20
Since the electric power of 0 W is incident, the temperature of the substrate 8 becomes high. In order to avoid this, if necessary, the substrate 8 can be connected through the cooling gas introduction pipe 12.
By introducing a cooling gas between the substrate electrode 9 and the substrate electrode 9, the substrate can be cooled.

Further, the target coil 7 of this embodiment, the coil inside the substrate
13 and the outer coil 14 are shown as electromagnet coils, the same effect can be obtained with a permanent magnet or a superconducting electromagnet, which is equivalent to the magnetic field.

Second Embodiment Next, a second embodiment in which the apparatus of the present invention is applied to a sputter etching apparatus will be described with reference to FIG.

Unlike the first embodiment, in the case of the sputter etching apparatus, 6 indicates a counter electrode corresponding to the first electrode. The counter electrode 6 is normally kept at ground or floating potential during the sputter etching process. High frequency power for generating plasma is applied to the substrate electrode 9 corresponding to the second electrode,
The same plasma 28 as in the first embodiment is generated. In the case of sputter etching, the bias mechanism 15 is not used. Other configurations are the same as those in the first embodiment.

In the sputter etching process, after moving the substrate electrode 9 on which a desired substrate 8 is to be processed to a processing position, high frequency power (not shown) is applied to the substrate electrode 9 to generate a high density plasma 28.
Generate. At this time, a self-bias voltage is induced on the surface of the substrate electrode 9, ions in the high-density plasma 28 are uniformly and highly incident on the substrate, and high-speed and uniform sputter etching processing is performed. Also at this time, the substrate can be cooled by introducing a cooling gas between the substrate 8 and the substrate electrode 9 through the cooling gas introduction pipe 12 as required.

Example 3 This example relates to a sputtering apparatus for forming a thin film as in Example 1, but differs greatly from Example 1 in that the attitude of the substrate to be processed during plasma processing is inclined by 90 °. If the first embodiment is called a horizontal type, this embodiment is called a vertical type (or a vertical type).

This embodiment will be described below with reference to FIG.

First, the difference from the first embodiment shown in FIG. 1 will be described. The substrate electrode 9 corresponding to the second electrode is attached to the rotary shaft 32 through the arm 31, and has a processing position indicated by the solid line in FIG. It is rotationally moved between the transport position shown by the chain line. Board 8
Are held on the substrate electrode 9 by a supporting means (not shown). The elevator 11 uses the spring 33 to keep the second
It is pushed to the left of the figure shown by the solid line. At the transfer position indicated by the alternate long and short dash line, the elevator cylinder 34 pushes the elevator 11 to transfer the substrate 8 to be processed onto the substrate electrode 9 from a transfer mechanism (not shown). The gas inlet pipe 12 for cooling the substrate is connected to the substrate 8 from the rotary shaft 32 via the arm 31.
And the substrate electrode 9.

The transfer means (29, 30 in FIG. 1) for transferring the substrate 8 is omitted as described above, but in principle it is the same as that in FIG. The gate valve for loading is shown in the figure.
Only 23 is shown.

The present embodiment operates as follows.

Through the gate valve 23 provided on the side wall of the vacuum container 1, the substrate 8 introduced from below in the vertical direction of the paper is carried to the center of the substrate electrode 9 at the carrying position by a carry-in mechanism (not shown). The elevator cylinder 34 is operated, the elevator 11 is raised, the substrate 8 is placed on the elevator 11, and after the substrate 8 is placed on the substrate electrode 9, it is supported on the substrate electrode 9 by a supporting means (not shown). Next, the rotary shaft 32 is operated to rotate the substrate electrode 9 to the processing position. Subsequent operations are the same as those in the first embodiment.

Example 4 A sputter etching apparatus having the same configuration as that of Example 2 was prepared using the apparatus shown in FIG. 2, and the same operation as that of Example 3 was performed.

〔The invention's effect〕

When the plasma processing apparatus of the present invention is configured as a sputtering apparatus for film formation, since plasma can be generated in a wide range on the target, the film formation rate and the target utilization rate are improved, and the substrate to be processed side is improved. Since the magnetic field lines created by the magnetic device are guided to the periphery of the substrate so that they do not cross the central part of the substrate, the ions in the plasma enter the substrate with high density and evenly, and on the surface of the thin film material deposited on the substrate. Migration can be uniformly promoted within the substrate.

As a result, a high-speed bias sputtering apparatus with high throwing power can be obtained. Further, even when the apparatus of the present invention is configured as a sputter etching apparatus, a sputter etching apparatus capable of uniformly processing at high speed can be obtained by uniformly injecting high-density ions into the substrate.

In the present invention, as described above, in any of the devices, the substrate electrode serving as the second electrode is moved between the transfer position of the substrate to be processed and the processing position, and the transfer means of the substrate to be processed is provided. The interlocking enables continuous processing of substrates and promotes mass production, which is of great industrial significance.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a main part of a plasma processing apparatus showing an embodiment of the present invention, and FIG. 2 is a vertical sectional view of a main part of a plasma processing showing another embodiment of the present invention. In the figure, 1 ... vacuum container, 2 ... gas valve 3 ... gas inlet pipe, 4 ... vacuum exhaust means 5 ... target electrode, 6 ... target 7 ... target coil, 8 ... substrate 9 ... substrate Electrode, 10 ... Electrode cylinder 11 ... Elevator, 12 ... Cooling gas introduction pipe 13 ... Substrate inside coil, 14 ... Substrate outside coil 15 ... Bias mechanism, 16 ... Contactor 17 ... Bias body, 18 ...... Roller 19 …… Groove, 20 …… Guide plate 21 …… Spring, 22 …… Bias cylinder 23,24 …… Gate valve, 25,26 …… Magnetic field 28 …… Plasma, 29,30 …… Conveying means 301 ...... Pulley, 302 …… Belt 31 …… Arm, 32 …… Rotary shaft 33 …… Spring, 34 …… Elevator cylinder

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mitsuaki Horiuchi 2326 Imai, Ome-shi, Tokyo Hitachi, Ltd. Computer Division, Device Development Center (56) References JP-A-62-70569 (JP, A) Kaisho 56-166374 (JP, A)

Claims (6)

[Claims] 1. A first electrode facing a processing surface of a substrate to be processed at a predetermined distance, and a second electrode on which the substrate to be processed is placed.
Between the first electrode and the second electrode, and the first electrode-side magnetic device and the second electrode-side magnetic device that generate a magnetic field between the first and second electrodes cooperate with each other. In a plasma processing apparatus that forms a cusp magnetic field, a magnetic field line generated by the second electrode-side magnetic device is opposite to the second electrode-side magnetic device so as not to cross at least the central portion of the substrate to be processed. A third magnetic device for generating lines of magnetic force is disposed inside the second electrode-side magnetic device, and a transfer position at which the substrate to be processed is placed on the second electrode and the substrate to be processed are subjected to plasma treatment. It comprises a moving means for moving the second electrode to and from a processing position and a transfer means for transferring the substrate to be processed to the transfer position, which enables continuous plasma processing. Plasma processing apparatus. 2. The plasma processing according to claim 1, wherein bias voltage applying means for generating a predetermined negative bias voltage is provided on the surface of the substrate to be processed on the second electrode. apparatus. 3. The second electrode penetrates through the inside thereof,
3. The plasma processing apparatus according to claim 1, further comprising cooling means for introducing a fluid for cooling the substrate to be processed between the substrate to be processed and the second electrode. 4. A plasma processing apparatus according to claim 1, 2 or 3, wherein high frequency power is applied to the second electrode. 5. A target made of a desired film forming material is placed on the first electrode, and the target is sputtered to form a thin film made of the desired film forming material on the substrate to be processed. The plasma processing apparatus according to claim 1, 2, 3, or 4 characterized in that. 6. A moving means for moving the second electrode comprises an electrode cylinder which is provided outside the vacuum container and is movable up and down. Further, a substrate to be processed is moved up and down on the second electrode. An elevator mechanism is provided to allow the operation to be performed. Claims 1, 2, 3, 4
Item 5. The plasma processing apparatus according to item 5.