JPH089779B2 - Sputtering apparatus and control method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sputtering apparatus capable of high-speed film formation at a low temperature and a control method thereof.

2. Description of the Related Art Conventionally, a magnetron sputtering device has been mainly used as a sputtering device, and has a configuration shown in FIG. The vacuum chamber 1 is provided with a vacuum exhaust system 2, a gas introduction system 3, a substrate holder 5 for fixing the substrate 4, and the like. The cathode part provided in the vacuum chamber 1 is configured as follows. The vacuum chamber 1 and the cathode holder 6 are electrically insulated from each other by an insulator 7, and a permanent magnet 8 arranged in a predetermined polarity is installed in the cathode holder 6. A backing plate 10 to which a sputtering target 9 is bonded is installed on the cathode holder 6 so as to be almost in contact with the permanent magnet 8. A cooling system 11 for cooling the permanent magnet 8, the sputtering target 9, the backing plate 10, etc. is also installed. The power required for sputtering is supplied from the power supply system 12. A shield ring 13 is attached to the vacuum chamber 1 for discharging.

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

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

As an example, when an ITO transparent electrode is prepared using an In (indium) oxide target and argon as a sputtering gas, the sheet resistance distribution of the prepared thin film is as shown by the solid line in FIG. 2 (a), A portion having a high sheet resistance is generated at a position corresponding to the inner magnet of the permanent magnet 8. Regarding the electron density 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 in this case, the electron temperature was almost constant, but the electron density was as shown in FIG. 2 (b). As indicated by the solid line in the figure, the sheet resistance was low in the portion where the electron density was high. From these results, it is considered that the sheet resistance distribution is generated for the following two reasons.

The first reason is that between the sputtering target 9 and the substrate 4, lines of magnetic force generated by the permanent magnets 8 are generated between the sputtering target 9 and the substrate 4, the substrate holder 5, the vacuum chamber 1 and the like. An electromagnetic field space is created by the lines of electric force that are present. In this space, the trajectory of the electron motion is a combination of a rotational motion with a constant angular velocity called a cycloid or a trochoidal curve and a constant velocity translational motion. FIG. 4 shows a schematic view of the main part of the sputtering source and the substrate 4 during sputtering. The region of frequent electron collisions due to the trajectory of this electron motion, that is, ionization and excitation are promoted and the electron density is high. Plasma 14
There are areas where At this time, the film-forming particles (In, O) sputtered from the erosion region 15 of the sputtering target 9 pass through the plasma 14 having a high electron density and reach the substrate 4. This electron-dense plasma 14
When passing through the inside, the film-forming particles (In, O) are excited and activated by colliding with electrons (ions and atoms in plasma are also considered), so In and O of the film-forming particles react with each other. It's easier to do. Therefore, it is presumed that O is appropriately incorporated into the thin film to form a high-quality film having a 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 (possibly ions and atoms in plasma) and film-forming particles (In, O) rarely occur. For this reason, In and O are hard to be excited, and thus are hard to react. For this reason, the amount of oxygen taken into the thin film becomes a predetermined value or less, and the sheet resistance increases. For the above reason, it is presumed that the sheet resistance distribution occurs as shown by the solid line in FIG. 2 (a).

Next, the second reason is that in the vicinity of the substrate 4 where the plasma 14 having a high electron density is generated, many plasma particles (ions, atoms, electrons) collide with the substrate 4 on the surface of the thin film, and It is thought that energy is applied to the thin film. However, at the position corresponding to the inner magnet of the permanent magnet 8 where the plasma having a low electron density is generated, it is considered that the number of particles colliding with the thin film surface is small, and the amount of energy obtained by the collision of the plasma particles with the thin film. It is estimated that the film growth process differs due to the difference in the sheet resistance and the sheet resistance distribution is generated as shown by the solid line in FIG. 2 (a).

In the above description, the occurrence of the film quality distribution when the film is formed using the In oxide target is explained by the sheet resistance, but the distribution also occurs in the transmittance, the crystallinity and the like for the same reason. Here, the transparent electrode prepared using an In (indium) oxide target has been described, but similar distributions also exist when forming thin films of compound materials such as other oxides and nitrides, and the magnetron This is an important problem in the sputtering method.

The present invention provides a sputtering apparatus and a control method thereof for reducing the film quality distribution in order to solve the above problems and forming a thin film having a uniform film quality.

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

Further, the control method of the sputtering device of the present invention, in the vicinity of the substrate, a position corresponding to the inner magnet of the permanent magnet,
It is characterized in that the electron density is controlled to be equal at a position corresponding to a portion between the inner magnet and the outer magnet of the permanent magnet.

Action The present invention causes the electron supply device to emit electrons by the above-mentioned configuration, and promotes ionization and excitation of surrounding particles by the electrons, thereby increasing the electron density even at the position corresponding to the inner magnet of the permanent magnet. Since the electron supply device is arranged inside the holes of the sputtering target and the backing plate, deposition of film-forming particles does not occur and stable electron supply is possible.

At this time, the electron density at the position corresponding to the inner magnet of the permanent magnet and the position corresponding to the portion between the inner magnet and the outer magnet of the permanent magnet in the vicinity of the substrate is detected by the probe, and each electron density becomes equal. As described above, it is controlled by the power supply system for the electron supply device.

Therefore, the electron density becomes high even at the position corresponding to the inner magnet of the permanent magnet, so that the film-forming particles are uniformly excited by the collision with the electrons, and become active and easily react. Further, since the electron density becomes high, the number of particles that collide with the thin film also increases. Therefore, a good quality film with a small film quality distribution can be obtained.

EXAMPLES Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram of a sputtering apparatus in one embodiment of the present invention. It should be noted that the same components as those of the conventional example described in FIG.

The permanent magnet 8 is provided with a sputtering target 16 having a hole 22 and a backing plate 17 at a position close to the inner magnet. An electron supply device 18 is installed inside the holes of the sputtering target 16 and the backing plate 17, and a probe 19 for detecting the electron density is installed near the substrate 4. An electron supply device power supply system 21 for controlling the amount of electrons supplied from the electron supply device 18 by a signal from a detection circuit system 20 installed in the probe 19 is provided.

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 19 arranged near the substrate 4 is moved to a position corresponding to the inner magnet of the permanent magnet 8 and the permanent magnet 8.
The electron supply at the position corresponding to the portion between the inner magnet and the outer magnet of the device is detected, and the amount of electrons supplied from the electron supply device 18 is supplied by the signal of the detection circuit system 20 so that the respective electron densities become equal. It is controlled by the device power supply system 21.

By the above control, the electron density at the position corresponding to the inner magnet of the permanent magnet 8 and the position corresponding to the portion between the inner magnet and the outer magnet of the permanent magnet 8 can be made equal,
As a result, the distribution of electron density becomes uniform as indicated by the broken line in FIG. 2 (b). Therefore, even at the position corresponding to the inner magnet of the permanent magnet 8, the film-forming particles (In, O) are uniformly excited by the collision with the plasma particles and easily react. Further, the number of plasma particles colliding with the substrate 4 also becomes uniform. Therefore, as shown by the broken line in FIG. 2 (a), a film having good quality and uniform sheet resistance can be obtained.

In the examples, the sheet quality is described as a representative of the film quality, but according to the present invention, the distribution of film quality such as transmittance and crystallinity can be made uniform.

EFFECTS OF THE INVENTION According to the sputtering apparatus and the method of controlling the same of the present invention, the uniformity of the formed thin film is dramatically improved by making the electron density distribution uniform and the plasma generated between the sputtering target and the substrate uniform. Can be increased to

As a result, a thin film having a uniform film quality can be produced in a large area with a high yield, and a great effect can be exerted in improving the performance of the product and reducing the cost.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a sputtering apparatus in one embodiment of the present invention, and FIGS. 2A and 2B are radial sheets when a transparent electrode is formed using an indium oxide target. FIG. 3 is a diagram showing a resistance distribution and an electron density distribution during film formation, FIG. 3 is a schematic configuration diagram of a sputtering apparatus in a conventional example, and FIG. 4 is a schematic diagram of a main part 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 supply system, 16 ... sputtering target, 17 ...... Backing plate, 18 …… Electronic supply device,
19 …… Search pole, 20 …… Detection circuit system, 21 …… Electronic power supply power supply system, 22 …… Hole.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number in the agency FI Technical indication location H05H 1/00 A 9216-2G (72) Inventor Yuji Mukai 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-2-290966 (JP, A)

Claims (2)

[Claims] 1. A vacuum chamber, an evacuation system, a gas introduction system, and a power supply system, and an inner magnet in a central part and an annular outer magnet in a peripheral part for generating a magnetic field for magnetron discharge in the vacuum chamber. A backing plate which is provided with a cathode holder having a permanent magnet, which is formed by bonding a magnet to a yoke plate, and a backing plate, to which a sputtering target is bonded, and which is relatively close to the inner magnet of the permanent magnet. A hole is provided in the center of the plate and the sputtering target, an electron supply device is installed inside the hole formed by the backing plate and the hole of the sputtering target, and an electron density detecting probe is installed near the substrate. Then
Further, the sputtering apparatus is provided with a power supply system for an electron supply device. 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 at a position corresponding to a portion between the inner magnet and the outer magnet of the permanent magnet. The method for controlling a sputtering apparatus according to claim 1, which is characterized in that.