JPH04210470A - Production of sputtering target - Google Patents

Abstract

PURPOSE:To obtain a high-purity sputtering target by introducing the vapor of the desired metal compd. into a high-vacuum reaction vessel and then irradiating a substrate in the vessel with light of specified wavelength to form a high- purity metal (alloy) film. CONSTITUTION:A reaction vessel 11 contg. a substrate 8 is evacuated to a high vacuum. The vapor of the desired metal or its compd. is introduced into the vessel 11 around the substrate 8. At this time, the substrate 8 is heated or cooled by a heater 9 or a cooling pipe 13. The substrate 8 is then irradiated with light of specified wavelength to form a desired metal film on the substrate 8.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a method for applying photo-CVD on a heated or cooled substrate.
The present invention relates to a method for manufacturing a high-purity sputtering target in which a high-purity metal film or alloy film is formed by a method.

<Prior art> In general, metal films for electrodes and wiring in semiconductor devices (T i + Mo, A I, W, et c
), a magnetic film (Co-Ni-Cr, Cr, etc.) can be formed by a sputtering method using a target of these metals or a compound target of an alloy containing the metals.

In the conventional sputtering method, impurities in the target are also sputtered together with the target base material and adhere to the opposing substrate.

The properties of the sputtered film obtained in this way are the purity of the film,
That is, it often depends on the purity of the target. The purity of the obtained membrane is not necessarily good.

Traditionally, this target has been manufactured using metal,
Melting, casting, rolling, cutting, alloys or their compounds
There is a method of manufacturing by polishing, etc., and a method of manufacturing by pressurizing and sintering powder of metal, alloy, or their compound by hot pressing, HIP, etc., followed by cutting, polishing, etc.

In the hot press method, an ingot with the desired composition is first created by melting, and then pulverized into powder while preventing oxidation. The particle size of the powder is generally 10 to 20 μm, and it is filled into a graphite mold and sintered under pressure at 1,100°C and about 2,000 kg/cm2 in vacuum or inert gas. It is something.

In addition, in the HIP method, a SUS can or the like is filled with powder of the desired composition, vacuum degassed, and heated to 1.100'C.

Pressure sintering is performed under conditions such as 2.000 kg/cm2.

<Problems to be Solved by the Invention> However, in the former method, even if melting and casting are performed in an inert gas, the target may be contaminated by oxygen and nitrogen that have entered, and furthermore, the target may be contaminated by the crucible or mold. Contamination also occurred.

In the latter method, since the powder has a large surface area, it is heavily contaminated by M elements and nitrogen, and contamination also occurs due to the crucible and crusher used during powder production.

<Objective of the Invention> Therefore, an object of the present invention is to provide a method for manufacturing a high-purity sputtering target necessary for manufacturing a high-purity film with few defects in a semiconductor device.

<Means and effects for solving the problems> In the method for manufacturing a sputtering target according to the present invention, a reaction vessel containing a substrate is evacuated to a high vacuum, and the target metal or This method of manufacturing a sputtering target involves introducing the vapor of the compound into the reaction vessel, and then irradiating the substrate with light of a predetermined wavelength.

Specifically, according to the method of the present invention, first, a reaction vessel containing a substrate that can be heated or cooled is prepared. In addition,
This reaction vessel has a light entrance window, a gas inlet, an exhaust port, and the like.

The reaction vessel is then evacuated to a high vacuum, such as 10 Torr, using, for example, a vacuum pump.

A vapor of the desired metal or alloy hydride, halide, or organometallic compound is then introduced into the reaction vessel. At this time, the substrate is heated or cooled and maintained at a predetermined temperature, and the introduced vapor is adsorbed onto the substrate. For example, if the temperature of the substrate is lower than the temperature of the colliding gas molecules, the heat will be absorbed by the substrate, the movement of the gas molecules will slow down, and they will be better adsorbed by the substrate. Furthermore, the optimum temperature for adsorption differs depending on the substance. Further, as this substrate, for example, a silicon substrate or a ceramic substrate such as quartz can be used. By appropriately selecting a substrate depending on the adsorbed substance, it is also possible to control the orientation of the crystals of the adsorbed substance.

After this, the reaction vessel is placed under high vacuum (10-”T o rr
). As a result, excess vapor that has not been adsorbed onto the substrate is discharged from the reaction vessel. In addition,
If the amount of steam supplied is properly adjusted, this evacuation step is unnecessary for the present invention.

Then, a laser beam of a predetermined wavelength is irradiated onto the substrate through the light entrance window. For example, the absorption curve of trimethylaluminum Al(CH3)3, a gaseous molecule, shows an absorption peak around a wavelength of 20 Onm. When this is irradiated with an ArF excimer laser, Al(CH3)3 undergoes photo-dissociation and metal atom aluminum Al is liberated. When these free metal atoms AI are deposited on a substrate, a metal thin film of AI is formed.

Then, the above steps are repeated until the target metal film has a desired thickness. This makes it possible to obtain a desired sputtering target.

"Reason for Limitation of the Invention" As described above, the present invention includes a vacuum evacuation process, a steam introduction process, and a light irradiation process. The reason why the invention is constituted by these steps will be explained.

First, the reaction vessel is evacuated.

This is to prevent the high purity metal film or alloy film adsorbed onto the substrate from being contaminated by oxygen, nitrogen, water, etc. remaining or attached to the reaction vessel.

Next, a vapor of a hydride, halide, or organometallic compound of the metal or alloy of interest is introduced into the reaction vessel. At this time, the substrate is being heated or cooled.

The vapor of a metal or alloy hydride, halide, or organometallic compound is adsorbed onto the heated or cooled substrate.

At this stage, there are differences in adsorption capacity depending on the introduced substance, and high purity is achieved by selecting the vapor to be introduced.

Then, light of a predetermined wavelength is irradiated through the light incidence window onto a specific portion of the substrate on which the substance has been adsorbed.

By irradiating a metal or alloy hydride, halide, or organometallic compound adsorbed on a substrate with light, the compound only in the irradiated area undergoes photoexcitation decomposition, resulting in atoms and molecules with orientation at selective positions. A high-purity metal film or alloy film with a constant film thickness that is controlled at a level is formed.

At this stage, by appropriately selecting the wavelength of the irradiated light, it is possible to selectively excite and decompose only the desired adsorbed substances. Furthermore, it performs a high purification action.

At this time, as a light source, an excimer, a dye laser, a deuterium lamp, a mercury lamp, a xenon lamp, etc. can be used.

<Example> Hereinafter, an example of the method for manufacturing a sputtering target according to the present invention will be described with reference to the drawings.

FIG. 1 shows a sputtering target manufacturing apparatus for carrying out the method of the present invention.

In this figure, 11 is a reaction container main body (chamber), and a support stand 12 for holding a substrate 8 is provided inside the reaction vessel main body (chamber). A heater 9 and a refrigerant vibrator 13 for maintaining the substrate 8 at a predetermined temperature, and a thermocouple 10 for temperature measurement are disposed on the support stand 12. In addition, in the figure, 5 indicates a refrigerant inlet of the refrigerant vibrator.

A sample gas (steam) is introduced into the reaction vessel 11 from a sample gas inlet 3 and can be evacuated from an exhaust port 4. Further, a light entrance window 6 is provided so that light of a predetermined wavelength can be irradiated onto the substrate 8, and the reaction vessel 11 can be maintained at a predetermined temperature by a heater coil 7.

Note that 1 is the inlet for the window glass purge gas into the container, and 2 is the inlet for window glass purge gas into the container.
indicate the inlet for inert gas into the container.

An embodiment of a method for manufacturing a sputtering target using the apparatus having the above configuration will be described.

First, while heating the reaction container 11 and the substrate 8 using the heaters 7 and 9, the vacuum pump is started to evacuate from the exhaust port 4 to a high vacuum.

The inside of the reaction vessel 11 has a predetermined degree of vacuum, for example, 10-"T.
After exhausting until the temperature becomes o r r, an inert gas is introduced into the reaction vessel 11 from the inert gas inlet 2 .

By repeating these evacuations and introduction of inert gas, oxygen, nitrogen, hydrogen, etc. remaining in the reaction vessel 11 (or adsorbed on the inner wall of the vessel) are eliminated.

Next, the vapor of the target metal or alloy hydride, halide, or organometallic compound is introduced into the sample gas inlet 3.
The liquid is introduced into the vicinity of the substrate 8 inside the reaction vessel 11 from the inside. At this time, the substrate 8 is heated to a predetermined temperature by the heater 9 or cooled by a coolant.

As a result, the vapor (compound) of the sample gas appears on the surface of the substrate 8.
is adsorbed.

Next, when the supply of the sample gas is stopped, the vacuum pump is started again to discharge excess vapor that has not been adsorbed to the outside from the container 11 through the exhaust port 4.

After this evacuation is completed, the substrate 8 inside the high vacuum container 11 is
Light of a predetermined wavelength (for example, laser light) is irradiated through the light input quartz window 6. As a result, the vapor metal compound adsorbed on the substrate 8 is decomposed.

Products other than the target metal (or target alloy) produced on the substrate 8 by the decomposition of this compound are removed from the container 11 by vacuum evacuation.

By repeating these steps, a desired metal film or alloy film with a desired thickness can be obtained on the substrate 8. That is, a Subalink target is manufactured.

Tables 1 to 4 below show experimental examples and comparative examples of film compositions.

Table 1-1 Table 2-2 (hereinafter referred to as blank space) Table 3-1 Table 3-2 L-11-Gori-1-----j-111
□-A Table 4-1 <Effects of the Invention> In the method for producing a sputtering target according to the present invention, a highly pure sputtering target can be produced.

Then, by performing suba ring using this suba link target, the selective position has orientation.
It is possible to form a highly pure metal film or alloy film with a constant film thickness by controlling the atomic and molecular levels.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing a schematic configuration of a target manufacturing apparatus according to an embodiment of the method for manufacturing a sputtering target of the present invention. Patent applicant Mitsubishi Metals Corporation

Claims (1)

[Claims] A reaction vessel containing a substrate is evacuated to a high vacuum, and while the substrate is heated or cooled, vapor of a target metal or its compound is introduced into the reaction vessel, and then a predetermined amount of vapor is introduced into the reaction vessel. A method for manufacturing a sputtering target, characterized by irradiating the substrate with light of a specific wavelength.