JPH02290970A - Sputtering device and controlling method - Google Patents

Abstract

PURPOSE:To reduce the film distribution and to form a uniform-quality thin film by controlling the electron density in the vicinity of a substrate through an electron feeder in a hole at a position close to the inner magnet of a permanent magnet of a target. CONSTITUTION:A sputtering gas is introduced from a gas inlet system 3, and a target 16 fixed to a cathode holder 6 contg. a permanent magnet 8 with polarity arrangement specified through a backing plate 17 and a substrate 4 placed on a substrate holder 5 are arranged in opposition to each other in a vacuum chamber 1 evacuated to a specified degree of vacuum by an evacuating system 2. Plasma is produced in the chamber 1 by a power source system 12, and the target 16 is sputtered to deposit a thin film on the substrate 4. In this case, the electron density is detected by an electron density detecting probe electrode 19 provided close to the substrate 4. The electron feeder 18 set in the hole 22 close to the inner magnet of the permanent magnet 8 is controlled based on the detection value through a detector system 20 and a power source system 21. The electron densities at the positions respectively corresponding to the inner magnet and outer magnet of the permanent magnet 8 are equalized, and the deposited thin film is homogenized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a subsotering apparatus capable of high-speed film formation at low temperatures and a control method thereof.

2. Description of the Related Art Conventionally, a magnetron sputtering apparatus has been mainly used as a sputtering apparatus, and has a configuration as shown in FIG. The vacuum chamber 1 includes a vacuum exhaust system 2,
A gas introduction system 3, a substrate holder 5 for fixing the substrate 4, and the like are installed. The cathode section provided within the vacuum chamber 1 is configured as follows. The vacuum chamber 1 and the cathode holder 6 are electrically insulated by an insulator 7, and a permanent magnet 8 having a predetermined polarity is mounted inside the cathode holder 6. Packing plate 1 bonded with sputtering target 9
0 is placed on the cathode holder 6 so as to be substantially in contact with the permanent magnet 8. A cooling system 11 for cooling the permanent magnet 8, sputtering target 9, packing plate 10, etc. is also installed. Power necessary for sputtering is supplied from a power supply system 12. A shield ring 13 is attached to the vacuum chamber 1 in order to perform electric discharge.

Film formation using this apparatus is performed as follows. A sputtering gas containing an inert gas such as argon as a main component is introduced from the gas introduction system 3 into the vacuum chamber 1 at a predetermined flow rate, and the degree of vacuum within the vacuum chamber 1 is set to a predetermined value by the evacuation system 2. Ru. When a voltage is applied from the power supply system 12 in this state, plasma is generated by magnetron discharge. Then, as a result of the ionized ions in this plasma colliding with the sputtering target 9, sputter particles are scattered from the sputtering target 9 and a thin film is formed on the substrate 4.

Problems to be Solved by the Invention However, the sputtering apparatus having such a configuration has a drawback in that the film quality distribution of the thin film on the substrate 4 is wide.

For example, when an ITo transparent electrode is created using an In (indium) oxide target and argon as a sputtering gas, the sheet resistance distribution of the created thin film is as shown by the solid line in Figure 2(a). Therefore, a portion with high sheet resistance occurs at a position corresponding to the inner magnet of the permanent magnet 8. In this case, regarding the electron density/degree and electron temperature of the plasma in the radial direction from the position corresponding to the inner magnet of the permanent magnet 8 in the vicinity of the substrate 4, the electron temperature was almost constant, but the electron density was b) As shown by the solid line in the middle,
The sheet resistance was low in areas with high electron density. From this result, the distribution of sheet resistance occurs as follows:
There are two possible reasons.

The first reason is that between the sputtering target 9 and the substrate 4, there are lines of magnetic force generated by the permanent magnet 8 and lines of force generated between the sputtering target 9 and the substrate 4, substrate holder 5, vacuum chamber 1, etc. An electromagnetic field space is created by the electric lines of force. In this space, the locus of electron motion is a combination of constant angular velocity rotational motion and uniform translational motion, called a cycloid or trochoid curve. Figure 4 shows a schematic diagram of the main part of the sputtering source and the substrate 4 during sputtering, and the locus of this electron movement shows areas where collisions with electrons occur frequently, i.e., where ionization and excitation are promoted and electron density is high. plasma 14
An area is created where this occurs.

At this time, the film forming particles (In10) sputtered from the erosion region 15 of the sputtering target 9 pass through the plasma 14 with high electron density and reach the substrate 4. When passing through this plasma 14 with high electron density,
Film forming particles (rn1 0) are electrons (ions in plasma,
In and O of the film-forming particles easily react with each other because they are excited and become active by colliding with other atoms (including atoms). Therefore, it is presumed that 0 is appropriately incorporated into the thin film, resulting in a high-quality film with low sheet resistance.

Here, since the electron density is low at the position corresponding to the inner magnet of the permanent magnet 8, collisions between electrons (ions and atoms in the plasma are also considered) and the film-forming particles (In, O) do not occur much. For this reason, In1o is difficult to be excited and therefore difficult to react with. Therefore, the amount of oxygen taken into the thin film becomes less than a predetermined value, and the sheet resistance increases. For the above reasons, it is presumed that the sheet resistance distribution occurs as shown by the solid line in FIG. 2(a).

The second reason is that in the vicinity of the substrate 4 where plasma 14 with high electron density is generated, many plasma particles (ions, atoms, electrons) collide with the substrate 4 on the thin film surface. It is believed that energy is given to the thin film. However, at the position corresponding to the inner magnet of the permanent magnet 8 where plasma with low electron density is generated, it is thought that the number of particles colliding with the thin film surface is small, and the energy gained by the thin film due to the collision of particles of this plasma increases. It is inferred that the film growth process is different due to the difference in the film thickness, and therefore a distribution of sheet resistance occurs as shown by the solid line in FIG. 2(a).

In the above description, the occurrence of film quality distribution when forming a film using an In oxide target was explained in terms of sheet resistance, but distribution also occurs in transmittance, crystallinity, etc. for the same reason.

Here, we have described a transparent electrode manufactured using an In (indium) oxide target, but other oxides,
A similar distribution also exists when producing thin films of compound materials such as nitrides, and is an important problem in magnetron sputtering.

In order to solve the above-mentioned problems, the present invention aims to reduce the film quality distribution and provides a sputtering apparatus and a control method thereof that form a thin film with uniform film quality.

Means for Solving the Problems In order to solve the above problems, the sputtering apparatus of the present invention includes installing a sputtering target and a packing plate having holes in the cathode part of the vacuum chamber at a position close to the inner magnet of the permanent magnet, The present invention is characterized in that an electron supply device is installed inside the hole, a probe for detecting electron density is installed near the substrate, and a power supply system for the electron supply device is further provided.

Furthermore, the method for controlling a sputtering apparatus of the present invention is such that the electron density at a position corresponding to the inner magnet of the permanent magnet and a position corresponding to the part between the inner magnet and the outer magnet of the permanent magnet is equal in the vicinity of the substrate. It is characterized by control.

Function The present invention emits electrons from the electron supply device with the above-described configuration, promotes ionization and excitation of surrounding particles by the electrons, and increases the electron density also at a position corresponding to the inner magnet of the permanent magnet. Since the electron supply device is disposed inside the sputtering target and the holes of the packing plate, deposition particles do not adhere to the sputtering target and electrons can be stably supplied.

At this time, near the substrate, the electron density at the position corresponding to the inner magnet of the permanent magnet and the position corresponding to the part between the inner magnet and the outer magnet of the permanent magnet is detected by the probe, and each electron density is equal. This is controlled by the power supply system for the electron supply device.

Therefore, since the electron density is also high at the position corresponding to the inner magnet of the permanent magnet, the film-forming particles are uniformly excited by collision with the electrons, become active, and become more likely to react.

Furthermore, since the electron density increases, the number of particles colliding with the thin film also increases. Therefore, a high-quality film with little film quality distribution can be obtained.

Example Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a sputtering apparatus in an embodiment of the present invention. It should be noted that the same components as those of the conventional example explained in FIG. 3 are given the same numbers and the explanation thereof will be omitted.

A sputtering target 16 and a packing plate 17 having a hole 22 located close to the inner magnet of the permanent magnet 8
Equipped with: An electron supply device 18 is installed inside the holes of the sputtering target 16 and the packing plate 17, and a probe 19 for detecting electron density is installed near the substrate 4. An electron supply device power supply system 21 is provided which controls the amount of electrons supplied from the electron supply device 8 using a signal from a detection circuit system 20 installed in the probe 19.

When plasma is generated by magnetron discharge, electrons are emitted from the electron supply device 18 using the electron supply device power supply system 21 . These electrons promote ionization and excitation of surrounding particles. The probe pole 19 placed near the substrate 4 is moved to detect the electron density at a position corresponding to the inner magnet of the permanent magnet 8 and a position corresponding to the part between the inner magnet and the outer magnet of the permanent magnet 8. The amount of electrons supplied from the electron supply device 18 is controlled by the electron supply device power supply system 21 using a signal from the detection circuit system 20 so that the electron densities of the electrons are equalized.

The above control makes it possible to equalize the electron density at the position corresponding to the inner magnet of the permanent magnet 8 and the position corresponding to the part between the inner magnet and the outer magnet of the permanent magnet 8, and thereby the distribution of the electron density is It becomes uniform as shown by the broken line in FIG. 2(b). For this reason, the film-forming particles (In10) are uniformly excited by collision with the plasma particles even at positions corresponding to the inner magnets of the permanent magnet 8, and become more likely to react.

Further, the number of plasma particles colliding with the substrate 4 also becomes uniform. Therefore, a film having good quality and uniform sheet resistance can be obtained as shown by the broken line in FIG. 2(a).

In this embodiment, sheet resistance was used to represent film quality, but according to the present invention, uniform distribution of film quality such as transmittance and crystallinity can be achieved.

Effects of the Invention According to the sputtering apparatus and its control method of the present invention, the uniformity of the formed thin film can be dramatically improved by uniformizing the electron density distribution and uniformizing the plasma generated between the sputtering target and the substrate. can be increased to

As a result, a thin film of uniform quality can be produced over a large area with a high yield, which is highly effective in improving product performance and reducing costs.

[Brief explanation of drawings]

Figure 1 is a schematic configuration diagram of a sputtering apparatus in an embodiment of the present invention, and Figures 2 (a) and (b) are radial sheets when transparent electrodes are formed using an indium oxide target. A diagram showing resistance distribution and electron density distribution during film formation, FIG. 3 is a schematic diagram of a conventional sputtering apparatus, and FIG. 4 is a schematic diagram of the main parts of the sputtering source and a substrate. 1. ．． ．． Vacuum chamber, 2,, vacuum exhaust system, 3. ．． ．．
Gas introduction system, 4. 、． Substrate, 6. ．． ．． cathode holder
8. ．． ．． Permanent magnet, 12. ．． ．． Power system, 16. ．． ．． Sputtering target, 17. ．． ．． Packing plate, 18. ．． ．． Electronic supply device, 19. ．． ．． Probing pole, 2
0. ．． ．． Detection circuit system, 21. ．． ．． Power supply system for electronic supply device, 22. ．． ．． Hole. Name of agent: Patent attorney Shigetaka Kurino and one other person 1g2 (a.) Alien 11i+

Claims (2)

[Claims] (1) A sputtering target comprising a vacuum chamber, a vacuum evacuation system, a gas introduction system, and a power supply system, and having a hole in the cathode portion of the vacuum chamber at a position close to an inner magnet of a permanent magnet arranged with a predetermined polarity; A sputtering apparatus characterized in that a packing plate is installed, an electron supply device is installed inside the hole, a probe for detecting electron density is installed near the substrate, and a power supply system for the electron supply device is further provided. (2) In the vicinity of the substrate, the electron density is controlled to be equal at a position corresponding to the inner magnet of the permanent magnet and a position corresponding to the part between the inner magnet and the outer magnet of the permanent magnet. The method of controlling a sputtering apparatus according to claim 1.