JPH02254160A - Plasma controller - Google Patents

Abstract

PURPOSE:To stably and automatically form a thin film having a uniform thickness by providing the specific plasma controller in a film forming device, such as magnetron sputtering device, which uses a glow discharge. CONSTITUTION:A substrate 16b to be formed with the film and a target 16a which is a film forming material existing in the position opposite to the substrate are disposed in a reaction vessel 16 of the magnetron sputtering device and the glow discharge is generated between the substrate 16b and the target 16a by a high-voltage power source 17 of a high frequency or DC for discharge to form the thin film of the target 16a material on the substrate 16b. The magnetic field conditions of the plasma region by the glow discharge in the vessel 16 are controlled by a change of the magnetic field by an electromagnet 15 in this case. Power sources 13, 14 by the plasma controller 11 are controlled by a host computer 18 to pulse-control the magnetic field conditions of the electromagnet 15 for generating the magnetic field at the time of the control; thereafter, the high-voltage power source 17 for glow discharge is stopped and the thin film having a desired compsn. and film thickness is stably and automatically formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention operates a film forming apparatus or a thin film processing apparatus using glow discharge according to settings such as the plasma position and residence time of a wafer to be formed. This invention relates to a plasma control device.

[Conventional technology]

In recent years, research and development of new materials and devices has led to the development of thin films with a wide variety of special structures. Typical examples include a laminated film in which a plurality of film materials are alternately deposited, and an alloy film in which a plurality of film materials are mixed crystal in an arbitrary composition ratio. There is also a gradient film in which the alloy composition is varied in the thickness direction of the film.

By the way, these laminated films 9 alloy films and gradient films must be formed with uniform composition, film thickness, etc. with high accuracy depending on their use. For this reason, operations such as controlling the electric power input to the high-voltage power source for glow discharge and controlling the excitation current for applying the magnetic field have become extremely complicated. Therefore, the workers who perform film formation in the research and development and production processes are specific persons who are skilled in operating the film forming apparatus.

Further, all settings of the film forming apparatus (for example, Magne I Ronspak apparatus or plasma CVD apparatus W) were manually performed by the operator.

Problems to be solved by the invention C] As explained above, in the past, a specific person deposited the film, and if the operator changed, the composition of the film would change, making it impossible to form a stable film. There were drawbacks. Moreover, even a certain skilled person cannot form a film having a large number of laminated layers, such as a superlattice film, with high precision and stability.

In addition, initial settings of the film deposition equipment (conditions for desired film formation composition, etc.)
Since the settings were made manually, there was a drawback that it took a long time to make the settings once.

With the downward motion setting, it was not possible to change the set value linearly over time or to change it repeatedly in steps, which was a factor that delayed research and development of new materials. For this reason, there has been a demand for a control device (plasma control device) that can automatically set approximately six conditions for the film forming apparatus.

The present invention has been made to eliminate the above-mentioned drawbacks, and aims to provide a plasma control device that allows uniform film quality to be obtained even by unspecified operators and that allows automatic settings.

[Means to solve the problem]

A plasma control device according to the present invention includes means for controlling the magnetic field conditions of a solenoid coil for magnetic field generation by pulse output, and a lower stage for stopping a high-voltage power source for generating glow discharge after sending out the pulse output. ing.

[For production]

After controlling the magnetic field conditions of the magnetic field generation solenoid 1 coil, the plasma control device stops the discharge high voltage power supply that is generating the glow discharge.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of a spanter device showing a first embodiment of the present invention.

In the figure, 11 is a plasma control device, 1.24 is a shutter drive unit, and 13 is an electric power (
Channel 1 power supply (hereinafter referred to as Cl11
(referred to as power supply), 1, 1. tJ is also a channel 2 power supply (hereinafter referred to as CH2 power supply), 16 is a vacuum vessel in which film formation or thin film processing is performed by high frequency glow discharge, 16a is a target solar I side electrode provided in the vacuum vessel 16, 16
bba tageno!・A substrate provided to face 16a, 16C is a shutter used for cleaning the surface of target 1.6a, 17 is a high voltage power source for discharging, 1
8 is a post computer, 18a is a GP-IB or RC that connects the host computer 18 and the plasma control device.
This is a communication line typified by H.232C. Note that arrows in the figure indicate various control signals.

Moreover, FIGS. 2(a) and 2(b) are block diagrams showing the inside of the high-voltage power source 17 for discharge shown in FIG. 1. Here, the figure (a) shows the case of direct current discharge, and the figure (b) shows the case of high frequency discharge.

In Figures (a) and (b), 17a is a DC high voltage power supply, 17b is an automatic matching box, and 17C is a high frequency power supply. Note that a counter signal is normally used as the discharge stop signal.

Furthermore, FIG. 4 shows the plasma control device 11 shown in FIG.
FIG. 2 is a detailed block diagram of FIG.

In the figure, 31 is a local control unit that controls the muco CH1 and CH2 power supplies 13 and 14 in order to provide electric power (excitation current) to the electromagnet 15, and 32 is a remote control unit that controls arbitrary function waveform settings according to commands from the host computer 18. A control unit 33 is a multiplexer that selects between an analog signal for controlling a stabilized power supply during remote control to control the power amplifier unit and an analog signal during L]-Cal control, and 34 is a separate unit from the plasma control device 11. A power amplification section (CH
1 and CH2 power supply 13. 1.4. , 35 is a polarity switching circuit, 36 is a current monitor circuit, and 37 is a counter output section.

The local control unit 31 also includes a CPU 31a, a control switch circuit 31. b. Counter setting/display section,
It consists of a digital setting circuit 31d and an analog setting circuit 31e.

Furthermore, the remote control section 32 is composed of a GP-18 interface 32a, an XI/A converter section 32b, an S inverter circuit 32C, and a trigger output circuit 32d.

Next, the operation of this embodiment will be explained. First, the local control section outputs an analog signal (pulse waveform signal) to the CHI and CH2 electrodes 13 and 14, which control the electromagnet 15 for magnetic field control. This analog signal controls the C, H1, and C112 power supplies 13 and 14, which are power amplification units, and sends out the output current or output type set by the local control unit 31.

That is, by changing the output current values of CH1 and CH2 and the output type EiE value during the time period shown in FIGS. The position of the resulting plasma ring or the moat of the plasma can be varied. For example, the plasma ring at time T+ is emitted 1p around the target throat 1.6b as shown in the explanatory diagram shown in FIG. 6(a). On the other hand, since the output current value is different at time T2,
As shown in the explanatory diagram of ), a plasma ring is generated in a concentric circle at the center of the target beam 16b. In addition, when the duty ratio of the output current of the Nolls waveform is changed over time, the ratio of the time when the plasma ring is on the outer periphery and the time on the inner periphery changes with the composition ratio of the top layer immediately after the start of film formation. The composition ratio of the top layer at the end of film formation can be changed in the film thickness direction. This makes it possible to accurately form films with a large number of laminated layers, such as thin films and superlattice films that require extremely delicate compositional structures, such as gradient films in which the alloy composition differs in the six directions of the film thickness. (Japanese Patent Application No. 183375).

Further, after the above set pulse signal is sent out, a signal (counter signal) for automatically stopping the high voltage power supply for discharging is sent out from the counter output section 37 (not shown in FIG. 4).

This is intended to save the labor of the operator and to save power.

Next, the remote control section 32 can output an arbitrary function waveform from the C111 and CH2 power supplies 13 and 14 under control from the host computer 18.

That is, the local control unit 31 controls the pulse waveform frequency, peak value (current value or voltage value), duty ratio, CH
In contrast, the remote control section 32 only controls the phase difference between the I and CH2 power supplies 13 and 14, as shown in FIG. 7(a).
As shown in b), the output waveform of Cl-11CH2 can be repeatedly changed linearly or stepwise with respect to time. This makes it possible to change the diameter of the plasma ring almost continuously as explained in Fig. 6, and variously control the special mode plasma determined by the cathode structure of the film forming apparatus and the electromagnetic coil specifications and arrangement. be able to. Therefore, the conditions for film formation become much wider, and we can expect results from research and development into new materials.

Furthermore, opening and closing of the shutter 16C relative to the plasma region can be controlled via the shutter drive circuit 12 by a trigger output circuit 32d (not shown in FIG. 4).

Normally, when a plurality of materials are mixed together in the vacuum container 16, cross-contamination occurs in which the materials mix with each other. In this case, it cannot be completely prevented even if the plasma ring or the like is controlled from outside the vacuum vessel 16. In contrast, in this embodiment, since the shutter 16C can be driven according to a preset blockogram, it is possible to prevent one material from scattering while sputtering another material. can. Therefore, there is no need for the operator to manually open and close the shutter 6c for each process as in the prior art.

Next, FIG. 3 is a block diagram of a sputtering apparatus showing a second embodiment of the present invention. In Figure ζ, the same or equivalent parts as in Figure 1 are given the same reference numerals. 21 is a plasma control device, 22 is an RF (high frequency) corresponding to a high voltage power supply
23 is an automatic matching device), and 24 is a gas flow rate controller. Further, S indicates a power and output control signal, S2 indicates a matching layer control signal, and block I corresponds to the high voltage power source 17 for discharging shown in FIG. Note that arrows in the figure indicate various control signals.

Now, the plasma control device 21 outputs a discharge start signal and a stop signal for the RF power source 22 for generating high frequency glow discharge, and also performs power control (current control and voltage control). Thereby, power suitable for a desired film formation speed can be supplied to the glow discharge in the vacuum vessel 16 uniformly or while being controlled in synchronization with the magnetic field conditions.

Furthermore, when using the RF power source 22, an automatic matching device 23 is controlled to match the impedance on the power source side (usually 50Ω or 75Ω) with the impedance on the load side (glow discharge side).

That is, when the magnetic field conditions are changed during film formation as explained in the first embodiment, the impedance on the glow discharge side changes rapidly. In order not to perform high-speed matching for this change,
In this embodiment, the automatic matching device 23 is controlled as the magnetic field conditions change. Therefore, a consistent state can be maintained at all times.

Next, the plasma control device 21 performs control via a gas flow rate controller 24 that controls the flow rate of atmospheric gas (for example, Ar gas) supplied into the vacuum vessel 16 . This allows the gas flow rate within the vacuum vessel 16 to be constant or to be changed in conjunction with changes in magnetic field conditions.

Furthermore, if multiple gas flow rate controllers are controlled in synchronization with the magnetic field conditions, the mixing ratio of atmospheric gases (for example, Ar gas and N2
gas) can be changed in synchronization with changes in the generation area of the plasma ring or the plasma mode.

In this way, the plasma control device in this example can form a film under preset conditions.
It is possible to control the plasma ring, which changes from moment to moment, as well as shutter control, discharge impedance, and high-speed automatic matching.

As a result, by setting film forming conditions in the plasma control device in advance, uniform film quality can be obtained even if the operator changes. In addition, in order to perform automatic control,
Film formation, which was previously impossible with manual settings, becomes possible.

In the above embodiment, the case where there are two electromagnets is shown, but it may be one or three or more.

Alternatively, a combination of a permanent magnet and an electromagnet may be used.

Furthermore, various control signals synchronized with magnetic field conditions can be used to control controllers other than those shown in the above embodiments (for example, a gas pressure controller instead of a gas flow rate controller).

〔Effect of the invention〕

As explained above, the present invention has the following excellent effects.

(1) Since the film forming apparatus or thin film processing apparatus is controlled according to preset conditions, constant film quality can always be obtained even if the operator changes.

(2) Since each condition is automatically controlled, it is possible to form a film with a fast stacking period, such as a superlattice film, for example.

(3) Main conditions of film forming equipment or thin film processing equipment (e.g.
(magnetic field conditions, high-voltage power supply, etc.), it is possible to match the constantly changing power supply or load impedance without delay.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a sputtering apparatus showing a first embodiment of the present invention, and FIGS. 3 is a configuration diagram of a sputtering apparatus showing a second embodiment of the present invention,
Fig. 4 is a detailed block diagram of the plasma controller ff1l shown in Fig. 1, Figs. 5(a) and (b) are current output tie l and char 1, and Fig. 6 is an explanation showing the plasma ring. 7(a) and (b) are time charts showing arbitrary function waveforms. 11.21... Plasma control device, 12... Shutter drive unit, 13... Cl- (1 power supply, 14... CH
2 Power supply, 16...Vacuum container, 16C...Shafter, 1
7...High voltage power supply for discharge, 18...Host computer, 22...RF main power supply 23...Automatic matching box, 24
...Gas flow controller.

Claims (1)

[Scope of Claims] In a film forming apparatus in which a plasma region generated by direct current glow discharge or high frequency glow discharge is changed by a plurality of magnetic field generation solenoid coils, the magnetic field conditions of the magnetic field generation solenoid coils are controlled by pulse output. and means for stopping a high-voltage power source for generating glow discharge after sending out the pulse output.