JPH02298268A - Forming device for thin film - Google Patents

Abstract

PURPOSE:To make stray capacity small and to prevent both the reduction of negative potential of a target and loss of high-frequency electric power by opposing the side face of the part impressed with the high-frequency electric power to a network earthing shield while keeping a gap. CONSTITUTION:A network earthing shield 9 is opposed to the side faces of both a cathode 3 being a part 24 impressed with high-frequency electric power and a target 8 so as to surround them while keeping a gap in the bottom part of a vacuum tank 1. The volume of the part 24 impressed with high-frequency electric power is reduced in comparison with the conventional method and therefore stray capacity is made small. Accordingly the target 8 can be sufficiently regulated to negative potential in order to sputter this target and loss of high-frequency electric power resulting from the stray capacity can be reduced. Therefor damage is not imparted to a thin film and refining of a semiconductor element, etc., is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thin film forming apparatus such as a high frequency sputtering apparatus used in the manufacturing process of semiconductors and the like.

(Prior Art) A conventional thin film forming apparatus, such as a high frequency sputtering apparatus, is shown in FIG. is attached to the cathode 3, and a matching box 4, a wattmeter 5, and a high frequency power source 6 are connected in series to the cathode 3. A target 8 is detachably attached to the upper end of the cathode 3 via a backing plate 7. Further, an earth shield 9 is attached to the bottom of the vacuum chamber l with gaps between the cathode 3, the backing plate 7, and the target 8, respectively, and the upper end of the earth shield 9 is approximately at the same height as the surface of the target 8. There is. An anode 10 is disposed in a vacuum chamber l above the target 8, and the anode 10 is
A board 11 is removably attached to 0. In addition,
In the figure, 12 is a discharge gas flow rate adjustment valve, 13 is an exhaust valve, 14 is a vacuum pump, and 15 is a vacuum chamber 1 and an insulator 2.
A rubber O-ring 16 is provided between the insulator 2 and
A rubber O-ring provided between the and cathode 3, 1
7 is a rubber O-ring provided between the cathode 3 and the backing plate 7.

In the above-mentioned high frequency sputtering apparatus, when the discharge gas is introduced into the vacuum chamber l through the discharge gas flow rate adjustment valve 12, plasma is generated between the cathode 3 and the anode 10 due to the electric field between them, and in the plasma The ions sputter the target 8, particles of the target 8 adhere to the substrate 11, and a thin film is formed on the surface of the substrate 11. In that case, the high frequency electric jl[6 applied to the cathode 3 is generally used at a frequency of 13.56 MHz, but it has not been confirmed whether this 13.56 MHz is the optimum frequency or not. .

(Problems to be Solved by the Invention) Conventional thin film forming apparatuses, for example, high frequency sputtering apparatuses, have a frequency of 13.5 without checking the optimum frequency.
A high frequency power source 6 of 6 MHz is applied to the cathode 3, but when the high frequency power source 6 of this frequency 13.56 MHz is used, the ion energy in the plasma is high, so that ions are formed on the surface of the substrate 11. Thin films are damaged by ions, and as the miniaturization of semiconductor devices progresses, this damage becomes undesirable.

Additionally, as semiconductor devices become smaller, vacuum chambers are needed to reduce impurities in the thin film formed on the surface of the substrate 11. It is necessary to prevent impurities from being contained in the discharge gas inside the O-ring 15.16.1, but since each O-ring 15.18.17 was made of rubber,
Due to degassing from 7, impurities are included in the discharge gas in the vacuum chamber 1, and under the influence of these impurities,
Problems such as deterioration of the quality of the thin film formed on the surface of the substrate 11 occurred.

Therefore, first, as a measure to prevent the thin film formed on the surface of the substrate 11 from being damaged by ions, the frequency of the high frequency applied to the high frequency power source 6 is changed to, for example, 27.
12MH! , 40. It is effective to lower the ion energy in the plasma by increasing it to 68MHL100MHx or the like.

However, in the above conventional device, the earth shield 9
Due to the gap between the cathode 3, backing plate 7 and target 8, the cathode 3, backing plate 7
Stray capacitance is generated in the target 8 and the cathode 3 to which high-frequency power is applied, the backing plate 7, and the target 8 itself. Therefore, the impedance of these becomes small, and the impedance of the high-frequency power supply 6 applied to the cathode 3 is reduced. Even if the frequency is increased, a large current flows through the cathode 3, and the target 8 does not reach a negative potential sufficient for sputtering, and high-frequency power loss occurs due to stray capacitance.

Therefore, in the conventional device described above, the frequency of the high frequency power source 6 cannot be increased.

Therefore, in order to make it possible to increase the frequency of the high-frequency power source 6, the conventional device described above must be improved and the cathode,
The volumes of the backing plate and target themselves are reduced to reduce their stray capacitance, and the opposing areas of the earth shield, cathode, backing plate, and target are reduced to reduce the stray capacitance caused by the gaps between them. There is a need. It is also necessary to increase the distance between the insulators to reduce the influence of dielectric constant and reduce stray capacitance.

Next, in order to prevent impurities from being contained in the discharge gas in the vacuum chamber i, it is necessary to replace the rubber O-ring with one that generates fewer impurities due to degassing.

In consideration of the above-mentioned problems, one of the purposes of this invention is to prevent a decrease in the negative potential of the target due to stray capacitance and a loss of high-frequency power, and also to prevent impurities in the discharge gas in the vacuum chamber. The aim is also to ensure that they are not included.

(Means for Solving the Problems) The thin film forming apparatus of the present invention connects the side surface of a part to which high frequency power is applied, which is insulated from a vacuum chamber, and a net-like earth shield arranged so as to surround this part, with a gap between It is characterized by facing each other with

The part to which the high-frequency power is applied consists of a cathode that is integrally formed with a plate-like horizontal part with protrusions along the periphery at the upper end of the central part of the columnar part, and a backing plate that is attached directly to the cathode. It consists of a target that is removably attached via a.

Furthermore, the part to which the high frequency power is applied is metallized and welded to the other end of a long insulator whose one end is metallized and welded to a mounting bracket that is attached to the opening of the vacuum chamber via a metal seal. , the distance between the mounting bracket and the part to which high-frequency power is applied is separated by the insulator.

(Function) In the thin film forming apparatus of the present invention, the side surface of the portion to which high-frequency power is applied faces the net-like earth shield with a gap, so the opposing area is reduced and the stray capacitance due to the gap is reduced.

Furthermore, since the volume of the portion to which high-frequency power is applied is reduced, stray capacitance due to volume is also reduced.

Furthermore, since the distance between the mounting bracket and the part to which high-frequency power is applied is increased by the insulator, the influence of the dielectric constant is reduced and the stray capacitance is reduced.

Furthermore, metal seals are used or both ends of the insulator are metalized and welded.
The generation of impurities from these due to degassing is reduced.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a high-frequency sputtering apparatus according to a first embodiment of the present invention. In the same figure, the same reference numerals as those in FIG. 3 showing the conventional apparatus are the same, and a description thereof will be omitted.
In the first embodiment of the present invention, unlike the conventional apparatus, a flange 22 corresponding to a mounting fitting is attached to the bottom opening of the vacuum chamber 1 via a metal seal 21. and,
One metalized end of a long insulator 23 is welded to the flange 22, and a portion 24 to which high frequency power is applied is welded to the other metalized end of the insulator 23. 22 and a portion 24 to which high-frequency power is applied are far apart. The part 24 to which high-frequency power is applied includes a cathode 3 which has a plate-like horizontal part 3c integrally formed with a plate-like horizontal part 3c having a protrusion 3b along the periphery at the upper end of a columnar central part 3a, and It is made up of a target 8 which is attached directly and removably. At the bottom of the vacuum chamber l, a net-like earth shield 9 connects the cathode 3, which is the part 24 to which high-frequency power is applied, and the target 8.
They face each other with a gap surrounding it on the sides.

Therefore, in the first embodiment described above, plasma is generated between the cathode 3 and the anode 10 due to the electric field between them, and ions in the plasma sputter the target 8, as in the conventional apparatus. Particles adhere to the substrate 11 and a thin film is formed on the surface of the substrate 11, but the opposing area due to the gap between the side surface of the portion 24 to which high frequency power is applied and the net-like earth shield 9 is reduced. Therefore, stray capacitance becomes smaller. Furthermore, since the volume of the portion 24 to which high-frequency power is applied is reduced compared to the conventional case, the stray capacitance due to the volume is also reduced. Insulator 2
3, the distance between the 7-lunge 22 and the portion 24 to which high-frequency power is applied is large, so that the influence of the dielectric constant is reduced and the stray capacitance is reduced.

Since the stray capacitance is reduced in this way, the target 8 can be made to have a negative potential sufficient for sputtering, and the loss of high-frequency power due to stray capacitance can be reduced, so that the frequency of the high-frequency power source 6 can be increased. becomes possible.

Additionally, a metal seal 21 or an insulator 2 may be used.
Since both ends of 3 are metalized and welded, the generation of impurities from these due to degassing is reduced.

Next, FIG. 2 shows a second embodiment of the present invention, in which an electromagnet 25 is disposed on the back of the cathode 3. As shown in FIG.

In each of the embodiments described above, the target 8 is directly attached to and detached from the cathode 3, but instead of this, the target may be detachably attached to the cathode 3 via a backing plate. Furthermore, in each of the above embodiments, a high frequency magnetron sputtering device is used.
Alternatively, it can also be used in plasma devices such as etching devices and CVD devices.

(Effects of the Invention) According to the present invention, since stray capacitance is reduced, the part to which high frequency power is applied can be brought to a sufficiently negative potential, and the loss of high frequency power due to stray capacitance can be reduced. , it becomes possible to increase the frequency of the high-frequency power supply. Therefore, semiconductor elements can be miniaturized without damaging the thin film. Further, according to the embodiment of the present invention, since a metal seal is used or both ends of the insulator are metalized and welded, impurities from these are less likely to be generated due to degassing. , the quality of the thin film will not deteriorate.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing a first embodiment of the invention, and FIG. 2 is an explanatory diagram showing a second embodiment of the invention. FIG. 3 is an explanatory diagram showing a conventional high frequency sputtering apparatus. In the figure, l... - Vacuum chamber 3 - Cathode 7 - Backing plate 8 - Target 21 - Metal seal 22 - 7 Lunge (installation) Metal fittings) 23... Insulator 24... Portion to which high frequency power is applied. In the drawings, the same reference numerals indicate the same or equivalent parts. Patent applicant: Japan Vacuum Technology Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] 1. A side surface of a part to which high-frequency power is applied, which is insulated from the vacuum chamber, is opposed to a mesh-like earth shield arranged to surround it with a gap therebetween. Thin film forming equipment. 2. The part to which high-frequency power is applied consists of a cathode that has a plate-like horizontal part integrally formed with a plate-like horizontal part with protrusions along the periphery at the upper end of the central part of the column, and this cathode, either directly or with a backing plate. 2. The thin film forming apparatus according to claim 1, further comprising a target detachably attached via a target. 3. Weld one metalized end of a long insulator to the mounting bracket attached to the opening of the vacuum chamber via a metal seal, and attach the part to which high-frequency power is applied to the other metalized end. 3. The thin film forming apparatus according to claim 1, wherein the thin film forming apparatus is also welded and the distance between the mounting bracket and the part to which high frequency power is applied is increased.