JPS62179115A - Filming device by sputtering process - Google Patents

Abstract

PURPOSE:To enable the precise composition to be controlled as well as the layer structured thin film to be formed by a method wherein the duty ratio, phase and frequency of electromagnet driving periodical current wave form built in a magnetron cathode are changed while the magnetron discharge state on targets is electrically turned on or off. CONSTITUTION:When permanent magnets 3a, 3b are impressed with periodically changing current (I) using individual electromagnet driving power supplies 5a, 5b, if the current is insufficient to be in the state of magnetron discharge immedi ately, the permanent magnets 3a, 3b or electromagnets are supplied with bias current to supplement magnetic field. For example, if the wave form of electro magnet driving current outputted from the power supplies 5a, 5b is periodical wave form, the precise composition of thin film can be controlled due to the fluctuation in deposit rate per time (C). At this time, if the targets 2a and 2b are respectively made of aluminium and silicon, aluminium and silicon can be simultaneously deposited in the spaces between pulse width (a) to form aluminium.silicon alloy with arbitrary composition ratio by changing the pulse width (a).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a sputtering film forming apparatus, and in particular, it is possible to precisely control the composition of compound thin films and mixture thin films formed by sequential f-sputtering of a plurality of targets of different materials. This invention relates to a magnetron sputtering film forming apparatus that enables control and formation of layered thin films.

Conventional technology Sputtering technology causes a glow discharge in a low-pressure atmospheric gas, turns the atmospheric gas into plasma, and collides with the target material of the cathode, removing deposit atoms and particles from the target material.
This is a film formation technology that scatters ions and deposits them on the substrate near the anode.

A magnetron cathode technique is known in which the atmospheric gas plasma generated by this glow discharge is confined at a high density in a space in contact with a target, thereby scattering deposited atoms and ions at a high rate. To confine high-density atmospheric gas plasma, a planar magnet is placed on the back side of the target material to cause electrons to move cycloidally under orthogonal magnetic fields, increasing the plasma density on the target surface. A magnetron type sputtering film forming apparatus has been developed.

Figure 6 shows the conventional method of co-sputtering (CO-sputtering).
1 is a schematic diagram of a sputtering deposition apparatus for depositing heterogeneous multi-material compound and mixture thin films known as uttering. The target material flat plates 12& and 12b are each arranged to face the substrate 11 on which sputtering atoms/ions are deposited.

A permanent magnet is built-in on the back side of the target, and a DC power supply 1 is installed.
Together with 4ia and 14b, an orthogonal electromagnetic field is formed to confine plasma at high density. Here, by changing the voltage applied to the sputtering cathode and the DC power supplies 142L and 14b, the speed at which sputtered particles are deposited onto the substrate from a plurality of targets (in this case, two targets are used for simplicity) is controlled. It is shown that the composition of the compound thin film and the mixture thin film can be varied and controlled.

The above describes the basic concept of co-sputtering, and does not describe the actually necessary vacuum pump, support stand for holding the pulp base, substrate heater, etc.

Problems to be Solved by the Invention However, in recent years, semiconductor device technology has
There is also interest in thin films with layered and superlattice structures.

Currently, research on superlattice structures using molecular beam epitaxy technology is active, but sputtering technology can be used to freeze high-temperature phases into a non-thermal equilibrium state, and to form thin films of high-melting point metals and insulating materials over large areas. It becomes possible to

However, when forming a layered thin film using conventional sputtering technology, (1) using a shutter, (2)
A method has been implemented in which the target is placed on a turntable and the positions of the target and substrate are switched, but it takes time to switch. For example, shutter 6a or 6
From the time when the shutter b begins to open until it is completely opened, the deposition rate is not constant depending on the area of the target region that is not covered by the shutter. In such a case, it is difficult to control the composition of the alloy thin film by simultaneous sputtering from a plurality of targets and to form a layer structure of a very thin film (several to several dozen). The same applies when switching the position of the target substrate.

The present invention has been made in view of this point, and it electrically controls the on/off state of the magnetron, and
It is an object of the present invention to provide a film forming apparatus by sputtering of compound thin films and mixture thin films whose composition is precisely controlled.

Means to Solve the Problem The present invention applies a current waveform whose duty ratio, phase, and frequency change periodically to an electromagnet placed on the back side of the magnetron target, and sequentially turns on and off the magnetron discharge state on the target. This device is equipped with a mechanism for sputtering.

Function The present invention forms a layered thin film, a compound thin film, and a mixture thin film by controlling the drive current waveform of the electromagnet with such a configuration, so that precise control is possible.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 shows a conceptual diagram of a magnetron multi-source sputtering film forming apparatus according to an embodiment of the present invention. Part or all of the permanent magnet built into the magnetron cathode in contact with the target is replaced with an electromagnet (31L, 3b), which is connected to an individual electromagnet driving power source (6a, sb). When a periodically changing current is applied by the individual electromagnet drive power supplies (5a, 5b), the permanent magnet (at, 3b) immediately enters the magnetron discharge state when no current is applied. Alternatively, a bias current is passed through the electromagnet to supplement the magnetic field.

For example, if the waveforms of the electromagnet drive currents output from the power supplies sa and 5b are made into periodic waveforms as shown in Figure 2 (A) and CB), it is possible to precisely control the composition of the thin film by changing the amount of deposition per time. becomes. In this case, if the target is 2&i aluminum and the target is 2bi silicon, aluminum and silicon are deposited simultaneously during the pulse width (b), and by changing the pulse width (a), an aluminum-silicon alloy with an arbitrary composition ratio can be formed. is possible.

Furthermore, if a periodic waveform with a timing that prevents the magneto-on discharge state is applied to multiple targets at the same time as shown in Fig. 3, the targets 2tL→2b→2
Since sputtering is performed in the order of a→2b→2&, it is possible to form a layered thin film.

In particular, by using a periodic waveform with an interval of several milliseconds, it is possible to form an entire thin film having a superlattice structure consisting of a monoatomic layer. In this case, if the target 22Li is aluminum and the target 2bf is silicon, a multilayer film of aluminum and silicon can be formed.

FIG. 4 shows a case where only the amount of additives is changed in the main component composition, and for example, target 2ai aluminum and target 2bi silicon can be used.

FIG. 5(A), ■) or FIG. 5(C), Φ) is a drive current waveform when forming a thin film with only two layers whose composition changes gradually. In this case, the target 2a can be made of molybdenum or 2bi aluminum.

Effects of the Invention As described above, the present invention differs from the conventional method of forming multilayer films and alloy films by mechanical mechanisms such as opening and closing shutters. Since the duty ratio (9 phases, 1 frequency) is changed and the magnetron discharge state on the target is electrically turned on and off, the discharge can be switched in a short period of time from several microseconds to several milliseconds. The period during which an uncertain film formation rate appears,
Precise composition control, as the reduction is negligible.
It is effective in forming thin films with a layered structure.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a magnetron multi-dimensional sputtering film forming apparatus according to an embodiment of the present invention, Fig. 2 is a waveform diagram showing the electromagnet drive current waveform when changing the composition of a thin film using the same apparatus, and Fig. 3 is a waveform diagram of the same apparatus. FIG. 4 is a waveform diagram showing the electromagnet driving current waveform when forming a layered thin film with the same apparatus.
Fig. 5 1...Substrate, 2...Target, 3...Electromagnet, 4...Permanent magnet, 5
······power supply. Name of agent: Patent attorney Toshio Nakao and 1 other person/
-m- board? ---Googet 3-11 Den J Namiishi 2nd diagram electrification equipment 3rd diagram 4th diagram 4th diagram 5th diagram denjin

Claims (3)

[Claims] (1) It has a magnetron having at least two or more targets, and an electromagnet is built into the back surface of the target for generating a magnetic field orthogonal to the electric field generated between the target, which serves as a cathode, and an anode. A sputtering film forming apparatus that independently generates the orthogonal magnetic fields necessary for a magnetron discharge state on a plurality of different targets by applying a predetermined drive current waveform that changes. (2) The sputtering film forming apparatus according to claim 1, which is capable of providing a drive current waveform having a predetermined waveform that prevents at least two targets from being in a magnetron discharge state at the same time. (3) It has at least two magnetic poles, and one of the magnetic field generation mechanisms uses an electromagnet, and uses a predetermined current waveform that changes periodically for the drive current of the electromagnet, and periodically changes the strength of the electromagnet. The sputtering film forming apparatus according to claim 1, wherein the magnetron discharge state can be turned on and off by changing the state.