JPH0649637A - Bias sputtering method - Google Patents

Abstract

PURPOSE:To form a densely vapor deposited film even on a surface which does not face a target by curving the incident direction of charge particles on a material by means of a magnet in the bias sputtering method. CONSTITUTION:The target 1 to which a DC power source 2 is connected, a rotating table 7 on which a substrate 9 for vapor deposition rides, a revolving table 6 which is connected to a high-frequency power source 4 via a matching circuit 3 and the permanent magnet 8 which is fixed to the revolving table 6 are installed in a vacuum chamber 5. The magnetic field in the radial direction of the revolving table 1 is applied to the substrate 9 for vapor deposition riding on the rotating table 7 and the locus of the Ar ions introduced by the high-frequency power source 4 is curved near the substrate 9 for vapor deposition when bias sputtering is executed by introducing the gaseous Ar constituting the charge particles from an introducing port 10 in this constitution. Since the substrate 9 for vapor deposition exists on the rotating table 7, the surface facing the infiltration direction of the Ar ions changes at all times and the entire periphery of the flank of the substrate 9 for vapor deposition is irradiated with the Ar ions. As a result, the uniform film is formed on the substrate 9 for vapor deposition having level differences and grooves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bias sputtering method which is particularly excellent for forming a sputtering film on a non-planar portion such as a step or a groove.

[0002]

2. Description of the Related Art A sputtering method or an ion plating method classified into physical vapor deposition is a magnetic head, L
It is widely used in the field of the electronics industry as a thin film forming means for electronic devices such as SI. Further, in the field of ceramics, it is necessary to form a metallized film on the surface of ceramics when joining ceramics to each other or joining metal and ceramics, and the physical vapor deposition method is also used here.

Even in the physical vapor deposition method having such an advantage, if there is a step or a groove in the target of vapor deposition, the amount of vapor deposition in the shadowed portion as seen from the vapor deposition source such as the target is reduced, or vapor deposition cannot be performed. There was a problem that the shadowing phenomenon occurred. For example, when an aluminum wiring of an LSI is to be formed by using a physical vapor deposition means, the contact portion of the LSI has a step, so that a shadowing phenomenon causes a disconnection. Therefore, during the film formation, the evaporation source or the material to be evaporated is periodically moved,
A method of reducing the shadowing phenomenon, such as decreasing the direction-dependent composition of the vapor deposition particles by constantly changing the direction in which the vapor deposition particles enter has been used.

[0004]

However, it is known that an appropriate film quality cannot be obtained when the surface of the material to be vapor-deposited is inclined with respect to the vapor-deposition source. Therefore, it is necessary to eliminate the direction dependence of vapor-deposited particles. , Shadowing cannot be prevented. For example, A. G. DIRKS and H.M. J. L
EAMY, Thin Oiled Films, 47
According to (1977) p219, when the inclination angle of the substrate surface to be vapor-deposited becomes 80 degrees, the density of the vapor-deposited film is higher than that when the inclination angle is 0 degrees (that is, the substrate surface perpendicular to the normal to the vapor deposition source surface). Was reported to be 50% or less, and such a decrease in density could not be solved only by eliminating the direction dependence of vapor deposition particles.

Further, as a method of increasing the density of the deposited film to improve the film quality, a bias sputtering method of simultaneously irradiating the deposited particles and accelerated charged particles or raising the temperature of the deposited substrate to diffuse the deposited atoms. It is also known how to activate it. However, since such a method utilizes the diffusion of atoms on the surface of the film or in the film, it is only effective in preventing shadowing of minute steps of at most several μm. An object of the present invention is to provide a bias sputtering method capable of extremely effectively suppressing a decrease in a vapor deposition film thickness due to shadowing and a reduction in a vapor deposition film density due to shadowing even when the thickness is several μm or more.

[0006]

The inventor of the present invention increases the density of a vapor deposition film in a step portion by irradiating the surface of the vapor deposition substrate which is not opposed to the target with a step due to the step, with charged particles by bias sputtering. At the same time, a method of preventing shadowing by studying a method of sputtering a part of a film deposited on a substrate by biased charged particles to supply the film to a surface not facing the target was studied, and arrived at the present invention. The present invention is a bias sputtering method in which sputtered particles from a sputtering target are deposited on a material and charged particles are made to enter the material, wherein the incident direction of the charged particles to the material is curved by a magnet. The bias sputtering method is as follows.

[0007]

The most characteristic feature of the present invention is that the incident direction of charged particles is curved by a magnet arranged near the vapor deposition substrate. For example, when argon is used as a sputtering gas, charged particles (argon ions and electrons) accelerated by supplying a high frequency power source to a table on which a vapor deposition substrate is placed in an ordinary bias sputtering device.
Is irradiated almost perpendicularly to the surface of the vapor deposition substrate facing the target. In this case, the surface that does not face the target is hardly irradiated with the charged particles, and the film quality on the surface that does not face the target and the surface that does not face the target are significantly different. On the other hand, in the present invention, the trajectory of the charged particles to the substrate by the bias sputtering is bent according to Fleming's left-hand rule, and the surface not facing the target is also irradiated, and the film on the vapor deposition surface not facing the target. Can be refined.

In the present invention, the charged particles incident on the target facing surface to which the vapor deposition particles are most attached have a specific incident angle largely inclined from the vertical. Therefore, a part of the film vapor-deposited by the charged particles is easily re-sputtered, and the re-sputtering can supply the vapor-deposited particles to the surface where the vapor deposition amount is small due to the conventional shadowing. This resputtering amount also depends on the incident angle of the charged particles described above. This resputtering can be controlled by controlling the magnetic field strength generated by the magnet that bends the trajectory of the charged particles and the accelerating voltage to the charged particles, but the deposition thickness is constant regardless of the substrate shape. Need to be adjusted. In addition, since the vapor deposition particles by the above-mentioned re-sputtering and the vapor deposition particles from the target direction are supplied from both directions to the wall surface of the base material having the step which does not face the target, the vapor deposition film on the wall surface has crystal growth in one direction. It is possible to obtain a dense and uniform film quality without being biased.

[0009]

【Example】

(Example 1) FIG. 1 shows a sputtering apparatus used in the present invention. The apparatus shown in FIG. 1 includes a target to which a DC power source 2 is connected, a rotation table 7 on which a vapor deposition substrate 9 is mounted,
The revolution table 6 connected to the high-frequency power source 4 via the matching circuit 3 and the permanent magnet 8 fixed to the revolution table 6 are installed in the vacuum chamber 5. In the apparatus of FIG. 1, both magnetic poles of the permanent magnet 8 are arranged so as to apply a magnetic field in the radial direction of the revolution table 6 to the vapor deposition substrate 9. Also,
The vacuum chamber 5 is grounded. It has an inlet port for argon gas that becomes charged particles and an exhaust port 11.

With such a structure, the magnetic field in the radial direction of the revolution table 1 is applied to the vapor deposition substrate 9 on the rotation table 7, and the trajectory of the argon ions guided by the high frequency power source 4 is near the vapor deposition substrate 9. It will be bent. Since the vapor deposition substrate 9 is on the rotation table 7,
The invading direction of the argon ions is always changed on the facing surface, and the entire circumference of the side surface of the vapor deposition substrate 9 can be irradiated with the argon ions. Bias sputtering was performed under the conditions shown in Table 1 using nickel as a target and a glass substrate of 10 × 10 × 5 t (mm) as a vapor deposition substrate. Table 2 shows the results of measuring the ratio of the film thickness at the center of the side surface of the substrate to the film thickness at the center of the surface facing the deposition substrate target. As shown in Table 2, it is understood that in the bias sputtering method in which the permanent magnet of the present invention is arranged, the film thickness on the side surface can be made closer to the film thickness on the target facing surface.

[0011]

[Table 1]

[0012]

[Table 2]

(Embodiment 2) Aluminum nitride 10 × 1
Using a 0 × 5 t (mm) sintered body substrate, an attempt was made to perform metallization treatment in the order of Ti and Ni to have thicknesses of 0.1 μm and 1 μm, respectively. In order to see the effect of the bias sputtering of the present invention, Ti was ordinary sputtering without a permanent magnet, and Ni was formed by the bias spalling method of the present invention by the apparatus shown in FIG. N in Table 3
The sputtering conditions for i are shown below.

[0014]

[Table 3]

FIG. 2 shows a sketch of the cross-sectional state of the Ni vapor deposition film formed on the side surface of aluminum nitride. See also FIG.
A sketch drawing of a similar portion of a comparative example in which no permanent magnet is arranged is shown in FIG. In FIG. 3 of the comparative example, Ni bends in one direction and crystal grows, and the boundaries of columnar crystals can be clearly confirmed.
It can be seen that the density of the film is low. On the other hand, in FIG. 2 using the method of the present invention, it can be confirmed that Ni has grown almost perpendicularly to the substrate and has become a dense film.

Next, Au was deposited on the obtained Ni film to a thickness of 0.1 μm by sputtering to obtain an aluminum nitride metallized substrate for soldering. Place Pb-10% Sn solder on the obtained metallized substrate and
The sample was evaluated by heating at 10 ° C. in a hydrogen atmosphere to spread the solder to the side surface and then heating at 310 ° C. for 1 to 30 hours in the atmosphere to evaluate the diffusion resistance of the solder to the metallized film. A Kovar pin having an adhesion surface of 2 mmφ was joined at a position 3 mm from the upper surface of the side surface of the obtained sample using Pb-Sn eutectic solder, and a tensile test was performed. The breaking strength of the metallized film obtained by this tensile test is shown in FIG. As a comparative example, the same evaluation was performed when Ni was vapor-deposited without a permanent magnet.

As shown in FIG. 4, the metallized film produced by the method of the present invention shows sufficient rupture strength even after being heated for 30 hours, whereas in the comparative example, it is annealed for 30 hours. A remarkable decrease in breaking strength is observed. This means that the vapor deposition film of Ni was dense in the present invention and was able to prevent the diffusion of solder to the metallized film, and the method of the present invention is particularly effective in improving the film quality on the side surface of the substrate where shadowing occurs. It shows that it was effective.

[0018]

According to the present invention, since the metallized film on the surface not facing the target can be made dense and the film thickness can be made uniform, which is impossible with the conventional bias sputtering method, vapor deposition with steps or grooves is achieved. The sputtering method is effective for the substrate.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus used in the method of the present invention.

FIG. 2 is a sketch showing a Ni vapor deposition film obtained by the method of the present invention.

FIG. 3 is a sketch showing a Ni vapor deposition film obtained by the method of the comparative example.

FIG. 4 is a diagram showing a relationship between a breaking strength and a heating time of metallized films obtained by the present invention and a comparative example.

[Explanation of symbols]

1 target, 2 DC power supply, 3 matching circuit,
4 high-frequency power source, 5 vacuum chamber, 6 revolution table, 7 rotation table, 8 permanent magnet, 9 vapor deposition substrate, 10 Ar
Gas inlet, 11 exhaust

Claims (1)

[Claims] 1. A bias sputtering method in which sputtered particles from a sputtering target are deposited on a material and charged particles are incident on the material, wherein the incident direction of the charged particles on the material is curved by a magnet. Characteristic bias sputtering method.