JPS6217174A - Production of thin film by dc magnetron sputtering device - Google Patents

Abstract

PURPOSE:To improve the utilizing efficiency of a target by regulating the magnet current of a DC magnetron sputtering device so that the magnetic field intensity of the target surface is made constant in the stage of forming the thin film of the target material on a substrate surface by the above-mentioned device. CONSTITUTION:Sputtering atoms are released from the target 2 to form the thin film consisting of the target material on the surface of the substrate by the DC magnetron sputtering device. Grooves are generated in the target 2 in this case and the negative discharge voltage -Vsp which is impressed to the target 2 and exists between the same and the substrate 1 decreases, then the value of sputtering electric power Wsp=VspXIsp decreases and the sputtering speed decreases when a constant current power source is used. The decrease of the magnetic field 5 on the target surface by the decrease of the discharge voltage -Vsp is prevented by regulating the magnet current IMg to maintain specified Wsp, by which the progression of the grooves generated in the target 2 is stopped. The utilizing efficiency of the target is thus improved and the thin film of th target 2 material is stably formed on the substrate 1 with high efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing thin films, typified by metal thin film magnetic recording media.

Conventional methods for producing thin films include sputtering, vacuum evaporation, and CVN, with sputtering and vacuum evaporation being particularly representative for forming metal thin films. Among these, in the case of alloys made of metals with a large difference in vapor pressure, the sputtering method is superior to the vacuum evaporation method. In the vacuum evaporation method, the composition of the ingot changes over time due to differences in vapor pressure. This is because, on the other hand, this phenomenon does not occur in the sputtering method. However, a disadvantage of the sputtering method is that the film formation rate (hereinafter referred to as rate) is very low, about several hundred times lower than that of the vacuum evaporation method. For this reason, many efforts have been made to date to improve the rate of the sputtering method, and among them, the DC magnetron sputtering method is considered to be a representative high-speed sputtering method. In particular, DC using electromagnets in the magnet part.
A method for manufacturing a thin film using a magnetron sputtering device will be described below with reference to the drawings.

FIG. 1 shows a schematic diagram of the main part of a DC magnetron type sputtering apparatus. In FIG. 1, a substrate 1 is grounded, and a negative voltage -vsF is applied to a target 2. In FIG. On the other hand, an electromagnet is arranged below the target, and a coil 4 is wound around each joke 3, and a magnetic field 5 is generated on the surface of the target 20 by the flow of the magnet current IMg. As a result, magnetron discharge occurs between the substrate 1 and the target 2, argon ions collide with the target 2, and sputtering atoms fly out from the target 2 and adhere to the substrate 1. There is a close relationship between the rate, discharge voltage vsp, and discharge current sp at this time, and this is shown in FIG. The horizontal axis is I51. Vertical axis vs
The figure shows equal rate lines when P is assumed, argon gas pressure is 8×1σ3 Torr, and magnet current error is constant: 40 A. From this, it can be seen that the rate in the DC magnetron sputtering method depends on the product of vsp and worksp, that is, input sputtering power Ws, = vsp x worksp.

Problems to be Solved by the Invention However, when attempting to perform sputtering over a long period of time using the DC magnetron sputtering method as described above, the following problems arose.

If sputtering continues for a long time, grooves (called erosion) will occur as the target is gradually dug away. Then, the magnetic field in this part becomes locally strong, VSP decreases, and if a constant current power supply is used, Ws
Since P decreases, the rate decreases. Traditionally, to avoid this rate fluctuation, ■. By increasing , Wsp was kept constant and rate fluctuations were suppressed. However, with this method, since the magnetic field strength in the erosion region is high once it has occurred, sputtering is concentrated in this region, and as the erosion progresses, the magnetic field strength becomes even stronger, and deep grooves are formed only in this region. ,
Eventually the target becomes unusable. A problem arises in that the utilization efficiency of the target used in this manner = ((target weight before use) - (target weight after use))/(target weight before heavy use) becomes extremely poor.

The present invention solves the above problems, and aims to produce thin films stably and highly efficiently by keeping the sputtering rate constant and improving target utilization efficiency. .

Means for Solving the Problems The present invention adjusts the current flowing through the magnet to prevent a drop in the discharge voltage that occurs when the target is heated during DC magnetron discharge, that is, an increase in the magnetic field strength on the target surface. The above object is achieved by stabilizing the discharge voltage by keeping the magnetic field strength always constant.

Effect of the present invention With the above configuration, in order to keep the discharge voltage of DC magnetron discharge constant, the magnet current is adjusted so that the magnetic field strength on the target surface is always constant, thereby stabilizing the film formation rate and making it easier to use the target. This will improve the rate.

Example An embodiment of the present invention will be explained below using the drawings.

The configuration of the sputtering apparatus is the same as that shown in FIG. 1, and the present invention is characterized by the control of the sputtering apparatus.

FIG. 2 shows the changes in the discharge voltage vsp and the discharge current sp when sputtering was performed with the magnet current set at a constant value of 40 people. Here, a constant current power source was used as the sputtering power source, and current adjustment was performed manually, so the graph has a step-like shape.

The target material is permalloy, and the argon gas pressure chamber is 8×1.
σ' Torr. As the erosion progresses, the discharge voltage decreases, so the discharge current is increased and
Adjusted to provide constant power. As shown in the table, the depth of the two lotions of the target after sputtering for 2-5 KW x 7 hours using this method was 1.8 mm.

On the other hand, Fig. 3 shows magnet electrician 1. When the discharge voltage vsp is made constant by changing the Vs,
The time changes of I, and gills are shown. Here, v
1. Automatically so that sp is constant. Since VSP is adjusted, VSP is always constant.

Target material and argon gas pressure are the same as above.

As the second lotion progresses, the magnetic field strength on the target surface increases, so the magnet current is reduced and the drop in discharge voltage vsP is suppressed. As shown in the table, the target lotion depth after 2-6 KW x 7 hours with this method was 1.2 mm.

Note that the erosion depth is a value shown in FIG. 4.

As shown in FIG. 3, according to this embodiment, the power input in the DC magnetron sputtering method is controlled by the magnet current, thereby making it possible to improve the target utilization efficiency.

Effects of the Invention As described above, the present invention is capable of stably and highly efficiently manufacturing thin films typified by metal thin film magnetic recording media, and its effects are significant.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the gun part of the DC magnetron sputtering apparatus including the present invention, and FIG. 2 is a vsP according to the conventional method.
FIG. 3 is a diagram showing the time change of SF, SF, and Mg. vsp, SP, AE,
FIG. 4 is an explanatory diagram for explaining erosion depth, and FIG. 6 is a diagram showing changes over time in discharge voltage V81. Discharge current worker, 1. FIG. 3 is a diagram showing the relationship between film deposition rates. 1...Substrate, 2...Target, 3.
River: York, 4: Coil, 6: Magnetic field, yM, Magnet current. Name of agent: Patent attorney Toshio Nakao and 1 other person, vote for ξmi - 肂ト7 - Soo! Mi1 -shoes-
Ni Tsubasa Mimi Atsujo No. 4 Zutabi Shinrantaka HP (Δ)

Claims (1)

[Claims] A thin film produced by a DC magnetron sputtering apparatus characterized in that a DC magnetron sputtering apparatus using an electromagnet in the magnet part is used, and the current flowing through the electromagnet of the apparatus is controlled in order to keep the plasma discharge voltage and discharge current constant. manufacturing method.