JP3116279B2 - Method of forming thin film using magnetron cathode - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for forming a thin film using a magnetron cathode, which is used when forming a thin film on silicon or another substrate in the manufacture of a semiconductor device or the like. About.

(Prior art) Conventionally, in the manufacture of semiconductor devices and the like, silicon,
As another method for forming a thin film on a substrate, a method using magnetron sputtering is known. In this magnetron sputtering, as shown in FIGS. 11 and 12, the disk target 51 and the substrate 52 face each other, while the magnetic field means 53 is rotatably installed on the back side of the disk target 51 so that the magnetron cathode The discharge is performed between the disk-shaped target 51 and the substrate 52 while rotating the magnetic field means 53, and the disk-shaped target 51 is sputtered to form a thin film on the substrate 52.

The magnetic field means 53 is constituted by connecting a center magnetic pole 54 and an annular magnetic pole 55 arranged on the outer periphery of the center magnetic pole 54 with a yoke 56, and the magnetic field lines indicated by 57 on the disc-shaped target 51. Is formed on the surface of the disk-shaped target 51 by sputtering, and an annular erosion portion 58 (which is formed into an annular shape by rotating the magnetic field means 53) as shown by a dotted line. It was something to be done.

FIGS. 13 and 14 show a magnetron sputtering apparatus that has been conventionally used. This device is an improvement of the device shown in FIGS. 11 and 12, and differs from the device shown in FIGS. 11 and 12 in the configuration of the magnetic field means 53 provided on the back surface of the disk-shaped target 51. That is, the magnetic field means 53 has an annular magnetic pole 55 provided along the periphery of the yoke 56, while the center magnetic pole 54 is
As shown in the figure, the two auxiliary magnetic poles 60 are installed so as to be deviated to one side from the center of rotation 59 and opposite to the deviating direction, inside the annular magnetic pole 55. It is composed.

In this apparatus, triple concentric erosion portions are formed on the surface of the disk-shaped target 51 by sputtering.
61 was formed.

(Problems to be Solved by the Invention) The magnetron sputtering apparatus as described above has been frequently used in the manufacture of semiconductor devices.
As the density and integration of semiconductor devices increase, various problems have arisen.

That is, firstly, it is difficult to cover all the contact holes with a uniform thin film with respect to the contact holes formed on the substrate, and the coverage becomes uneven at positions in the substrate. was there. There is also a problem that the coating with the thin film is unevenly biased even in the individual contact holes.

Although the device shown in FIGS. 13 and 14 has been considerably improved with respect to the above-mentioned problems as compared with the device shown in FIGS. 11 and 12, a recent increase in density and integration has been achieved. In this situation, further improvement has been required.

SUMMARY OF THE INVENTION The present invention solves the above-described problems, and provides a thin film using a magnetron cathode in which step coverage with respect to a contact hole at each position in a wafer is made uniform and a film thickness distribution in the wafer can be made uniform. It is an object of the present invention to provide a method for forming a thin film.

(Means for Solving the Problems) According to the method of forming a thin film using a magnetron cathode of the present invention, a magnetron cathode is formed by rotatably installing a magnetic field means on the back surface of a disk-shaped target. In the method of forming a thin film by sputtering on a substrate opposed to the above, the diameter of the substrate is 1 / 2D when the diameter of the disk-shaped target is D.
Before and after, the magnetic field means, two arc-shaped sides with respect to the center,
The central magnetic pole is eccentrically arranged in an annular magnetic pole consisting of two chordal sides, connected by a yoke, and an auxiliary magnetic pole is arranged. The distance between the disk-shaped target and the substrate is determined by the diameter of the disk-shaped target. In the case of D, 12 / 61D to 15 / 61D, the profile of the erosion formed on the surface of the disk-shaped target, the peak position is 15 / 152D to 20 / 152D and 50 / 152D, where D is the diameter of the disk-shaped target. A method of forming a thin film using a magnetron cathode, characterized in that the erosion intensity ratio at each peak position is 2: 3 to 1: 1 inside and outside, being a concentric double circle having a position of ~ 60 / 152D. .

Another method is to form a magnetron cathode by rotatably installing a magnetic field means on the back surface of a disk-shaped target, and forming a thin film by sputtering on a substrate opposed to the disk-shaped target of the magnetron cathode, The magnetic field means distributes a magnetic field strength of 15 cm from the center between 500 KG and -200 KG, at least from the center
The magnetic field is distributed so that it is constant at 500 KG during 5 cm and then linearly decreases until 14 cm, and the erosion profile formed on the surface of the disc-shaped target is
The peak position is 15/152, where D is the diameter of the disk-shaped target.
D ~ 20 / 152D and 50 / 152D ~ 60 / 152D are concentric double circles, and the erosion intensity ratio of each peak position is inside and outside 2:
This is a method of forming a thin film using a magnetron cathode, characterized in that the diameter of the substrate is about 1 / 2D when the diameter of the disk-shaped target is D, and the disk-shaped target and the substrate Is set to 12 / 61D to 15 / 61D when the diameter of the disk-shaped target is D.

(Operation) According to the present invention, the film thickness distribution in the wafer can be made within ± 5%, and the variation in step coverage with respect to the contact hole in the wafer and the deviation in the hole can be reduced.

(Example) The conditions in the method of the present invention were obtained as a result of performing the following running experiment and simulation of thin film deposition.

First, a running experiment (2 KW, 100 hours) was performed using the conventional apparatus shown in FIG. 13 to obtain an erosion profile of the target as shown in FIG. The target diameter was set to 12 inches, the wafer diameter was set to 6 inches, and the distance between the wafer and the target was set to 65 mm.

From the results shown in FIG. 1, the erosion depth was measured every 2 mm from the center. Then, the film thickness deposited on the wafer was calculated on the assumption that the depth of the erosion is the particle strength of the sputtered particles and that the sputtered particles fly from each point to the wafer side according to the cosine law.

In the wafer, there were contact holes having a diameter of 1 μm and a depth of 1 μm at the center position and at positions 40 mm and 80 mm from the center, respectively.

2 (a), 2 (b) and 2 (c) show the results of the above calculations, and FIGS. 3 (a), 3 (b) and 3 (c) show the SEM photographs when the film was actually applied. 1 is a cross-sectional view of a contact hole drawn based on a photograph, wherein the upper part is a drawing and the lower part is a photograph. (A) is a center position, (b) is a position 40 mm from the center, and (c) is a contact hole at a position 80 mm from the center.

From FIG. 2 and FIG. 3, it was confirmed that the simulation calculation was in good agreement with the actual one.

Next, a running experiment of the magnetron cathode 1 shown in FIGS. 4 and 5 was performed in the same manner.

The magnetron cathode 1 has a magnetic field means 4 rotatably installed on the back side of a disk-shaped target 3 facing a substrate 2.

As shown in FIG. 2, the magnetic field means 4 has a plane rectangular center electrode 6 (S
Pole) and an annular magnetic pole 7 (N pole) disposed around the center magnetic pole
Are connected by a yoke 8. An auxiliary magnetic pole 9 is provided on one side surface (the rotation center 5 side) of the center magnetic pole 6, and
Auxiliary magnetic poles 10, 11, 12, 1 inside and outside of annular magnetic pole 7
3 and 14, and a plate-shaped auxiliary magnetic pole 1 inside the annular magnetic pole 7.
5 are superposed and provided, and another auxiliary magnetic pole 1 is provided in the auxiliary magnetic pole 15.
6 incorporated.

By adjusting the positions of the auxiliary magnetic poles 9 to 16 in the magnetic field means 4, the magnetic field distribution on the surface of the disk-shaped target 3 changes, but the magnetic field distribution shown in FIG. (Measured in the vertical direction in the figure), it was found that a concentric double circle could be formed as shown by the dotted line in FIG.

The erosion profile obtained as a result of the running experiment (200 KwH) was as shown in FIG. The shapes of the deposited films obtained from the erosion profile by the same simulation calculation as described above are shown in FIGS.
9 (c), and SEM photographs and cross-sectional views of contact holes drawn based on the photographs are shown in FIGS. 9 (a), 9 (b) and 9 (c) (the upper part is a drawing and the lower part is a photograph). ). Also in this case, it was recognized that the simulation calculation was in good agreement with the actual one.

Also, as shown in the step coverage values shown in the contact holes of FIGS. 2 and 7, FIGS.
It was found that the bias of the step coverage can be improved by the apparatus shown in the figure.

Next, FIG. 10 shows the film thickness distribution when the magnetron cathode 1 shown in FIGS. 4 and 5 is used. The solid line in the figure is the experimental result, and the dotted line is the result of the simulation calculation. In each case, the agreement was well within ± 5%.

From the above results, it was found that when sputtering is performed using the magnetron cathode 1 shown in FIGS. 4 and 5, the film thickness distribution can be improved, and the step coverage deviation in the contact hole can also be improved.

Therefore, the conditions of the erosion profile of the magnetron cathode that can make the film thickness distribution within ± 5% and the step coverage within ± 10% were obtained by the same simulation calculation. As a result, when the diameter of the target is D, 15 / 152D to 20 / 152D and 50 / 152D to 60 / 152D from the center
There is a peak at the position, and each erosion intensity ratio is 2:
It was found that the above condition was satisfied when the ratio was 3 to 1: 1.

The distance between the substrate and the target is determined by the
12 / 61D to 15 / 61D.

(Effects of the Invention) As described above, according to the present invention, the direction of incidence of sputtered atoms on the substrate is made uniform, the dispersion and bias of coverage are eliminated even for contact holes having a high aspect ratio, and ± 5
% Or less, there is an effect that a semiconductor device with high density and high integration can be manufactured with high reliability.

[Brief description of the drawings]

FIG. 1 is a diagram showing an erosion profile of a target of a conventional apparatus, FIGS. 2 (a), (b) and (c) are cross-sectional views of a contact hole portion by simulation calculation based on FIG. 1, and FIG. a), (b), and (c) are cross-sectional views based on a scanning electron micrograph and a photograph showing a metal structure of a wafer on which a thin film is deposited by a conventional apparatus, and FIG. FIG. 5 is a plan view of the magnetic field means, FIG. 6 is a graph of the magnetic field distribution, FIG. 7 is a view showing an erosion profile of the target of the apparatus using the embodiment,
(B) and (c) are cross-sectional views of a contact hole portion by a simulation calculation based on FIG. 7, and FIGS. 9 (a), (b) and (c) show thin films deposited by an apparatus using the embodiment. FIG. 10 is a scanning electron micrograph showing the metallographic structure of the wafer and a sectional view based on the photograph, FIG. 10 is a graph showing the film thickness distribution of the apparatus using the embodiment, FIG. 11 is a sectional view of the magnetron cathode of the conventional apparatus, FIG. 12 is a plan view of the magnetic field means, FIG. 13 is a sectional view of a magnetron cathode of another conventional apparatus, and FIG. 14 is a plan view of the magnetic field means. DESCRIPTION OF SYMBOLS 1 ... Magnetron cathode 2 ... Substrate 3 ... Disc-shaped target 4 ... Magnetic field means 6 ... Central magnetic pole 7 ... Annular magnetic pole 8 ... Yoke 9, 10, 11, 12, 13, 14, 15 , 16 …… Auxiliary magnetic pole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C23C 14/00-14/58

Claims (2)

(57) [Claims] 1. A method of forming a magnetron cathode by rotatably installing a magnetic field means on the back surface of a disk-shaped target, and forming a thin film by sputtering on a substrate facing the disk-shaped target of the magnetron cathode. The diameter of the substrate is about 1 / 2D when the diameter of the disk-shaped target is D, and the magnetic field means is disposed with the center magnetic pole eccentrically arranged in an annular magnetic pole composed of two arc-shaped sides and two arc-shaped sides with respect to the center. Connected with a yoke and arranged with an auxiliary magnetic pole, the distance between the disk-shaped target and the substrate is 12 / 61D to 15 / 61D when the diameter of the disk-shaped target is D, and the disk-shaped target is The profile of the erosion formed on the surface of the target is 15 / 152D to 20 / 152D and 50 / 152D to 60 / 152D, where D is the diameter of the disk-shaped target.
The method for forming a thin film using a magnetron cathode, wherein the erosion intensity ratio at each peak position is 2: 3 to 1: 1 inside and outside 2. A method for forming a magnetron cathode by rotatably installing a magnetic field means on the back surface of a disk-shaped target, and forming a thin film by sputtering on a substrate facing the disk-shaped target of the magnetron cathode. Use magnetic field means to increase the strength of the magnetic field up to 15 cm from the center.
Distributed between 500KG and -200KG, at least 5c from center
During this period, the magnetic field is distributed so as to decrease linearly up to 14 cm, and when the diameter of the disk-shaped target is D, it is about 1 / 2D. When the diameter of the disk-shaped target is D,
12 / 61D to 15 / 61D, and the profile of the erosion formed on the surface of the disk-shaped target, the peak position is 15 / 152D to 20/15, where D is the diameter of the disk-shaped target.
2D and 50 / 152D to 60 / 152D concentric double circle,
A method of forming a thin film using a magnetron cathode, wherein the erosion intensity ratio at each peak position is 2: 3 to 1: 1 inside and outside