JP7144032B2 - Manufacturing method of container for evaporation raw material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a container for evaporation raw materials. More specifically, the present invention relates to a method for manufacturing a vaporization raw material container having excellent corrosion resistance.

Conventionally, an evaporation source container is known as a container for storing an evaporation source in, for example, a chemical vapor deposition (CVD) method. etc. have been reported (see Patent Document 1).

Japanese Unexamined Patent Application Publication No. 2016-866

However, the evaporator as described in Patent Document 1 employs stainless steel for the container wall, and although this stainless steel container wall has good thermal conductivity, it does not have sufficient corrosion resistance. There is a problem.

Here, in recent years, there has been a demand for further high performance semiconductor products, and as a result, there has been a demand for higher-purity vaporization raw materials (that is, vaporization raw materials with a lower percentage of impurities). there is

Here, although stainless steel has corrosion resistance, it corrodes slightly when it comes into contact with the evaporated raw material, and a very small amount of impurities may be mixed in the evaporated raw material. Also, with Hastelloy, as with stainless steel, a very small amount of impurities may be mixed in the evaporated raw material.

In other words, recently, even containers made of stainless steel do not have sufficient corrosion resistance, and there is a demand for the development of evaporation source containers (evaporator bodies) with further corrosion resistance. ing. In particular, when depositing a film by atomic layer deposition (ALD), the film must be defect-free and uniform at the atomic level, so the amount of impurities contained in the evaporated raw material must be minimized In particular, the inventors of the present invention have focused their attention and completed the present invention to solve such problems.

The present invention has been made in view of such problems of the prior art. According to the manufacturing method of the evaporation source container of the present invention, the evaporation source container having excellent corrosion resistance is obtained by forming at least a part of the inner surface of the container wall from a nickel alloy, aluminum, or an aluminum alloy. can provide.

According to the present invention, there is provided a method for manufacturing an evaporative raw material container described below.

[ 1 ] A sealable container body having a thermally conductive container wall;
a carrier gas introduction port for introducing a carrier gas into the container body;
A method for manufacturing an evaporative raw material container comprising: a mixed gas outlet for discharging a mixed gas of the evaporative raw material and the carrier gas in the container main body to the outside of the container main body,
providing a sealable green container body having a thermally conductive container wall;
A method of manufacturing an evaporation source container, comprising: polishing the inner surface of the untreated container body under the following condition (i) to obtain the polished container body.
Condition (i):
Using an electrode with a diameter of 250 to 350 mm, a current density of 28.5 mA/cm ² or less, an electrolytic solution concentration of 15 to 30% by mass, a liquid flow rate of 1 to 8 L/min, an electrolytic solution pH alkaline, and Polishing conditions are a pressure of 20 to 60 kPa and a rotational speed of 350 rpm or less, and inorganic particles having an abrasive grain size of 0.020 to 0.10 μm are used as abrasive grains.

According to the method for manufacturing an evaporation source container of the present invention, it is possible to manufacture an evaporation source container having excellent corrosion resistance.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view schematically showing one embodiment of a vaporization raw material container of the present invention; 2 is an enlarged cross-sectional view schematically showing an enlarged region P shown in FIG. 1; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments for carrying out the present invention will be described below, but the present invention is not limited to the following embodiments. In other words, it is understood that any modifications, improvements, etc., made to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention also belong to the scope of the present invention. should.

[1] Vaporizing raw material container:
One embodiment of the evaporation source container of the present invention is the evaporation source container 100 shown in FIG. This evaporation source container 100 includes a sealable container body 10 having a thermally conductive container wall 20, a carrier gas inlet 12 for introducing a carrier gas into the container body 10, and an evaporation source inside the container body 10. and a mixed gas outlet port 42 for leading out the mixed gas of the carrier gas and the carrier gas to the outside of the container body 10 . At least a part of the inner surface of the container wall 20 is made of nickel alloy, aluminum, aluminum alloy, or super stainless steel, which has been polished according to the predetermined condition (i) described later. Specifically, the container wall 20 is composed of two layers, an inner wall 23 and an outer wall 21 (see FIG. 2). (eg, Hastelloy, Inconel, etc.). The container body 10 also includes a lid 31 having the carrier gas inlet 12 and the mixed gas outlet 42 , and a receiver 32 for the lid 31 .

At least part of the inner surface of the container wall 20 of the evaporation source container 100 is made of nickel alloy, aluminum, aluminum alloy, or super stainless steel, which has undergone a predetermined polishing treatment, so that it is resistant to corrosion. It is excellent. Here, if the corrosion resistance of the evaporation source container 100 is poor, the evaporation source is contaminated with impurities (impurities are mixed in the evaporation source), which hinders the manufacture of semiconductor products with higher precision. end up As described above, recently, it has become important to be particularly excellent in corrosion resistance.

Of the nickel alloys, aluminum, aluminum alloys, and super stainless steel that constitute the inner surface of the container wall 20, examples of nickel alloys include Hastelloy and Inconel. is an alloy containing Ni and Mo.

The composition of "Hastelloy" can be determined as appropriate, but specifically, it contains 40 to 60% by mass of Ni and 30 to 50% by mass of Mo.

The composition of "Inconel" can be determined as appropriate, but specifically, Ni is 20 to 50% by mass and Mo is 70 to 50% by mass.

"Super stainless steel" means 17.00 to 19.50% by mass of Ni, 19.00 to 21.00% by mass of Cr, 5.50 to 6.50% by mass of Mo, and 0.16 to 0% of N. .24% by mass, containing 0.50 to 1.00% by mass of Cu, furthermore, C is 0.020% by mass or less, Si is 0.80% by mass or less, Mn is 1.00% by mass or less, and P is 0 0.030% by mass or less, S content is 0.015% by mass or less, and corrosion resistance is further enhanced.

The inner surface of the container wall 20 is polished under predetermined conditions. By polishing the inner surface in this way, the corrosion resistance is remarkably improved. Here, the polishing process is performed under the following conditions (i).
Condition (i):
Using an electrode with a diameter of 250 to 350 mm, a current density of 28.5 mA/cm ² or less, an electrolytic solution concentration of 15 to 30% by mass, a liquid flow rate of 1 to 8 L/min, an electrolytic solution pH alkaline, and Polishing conditions are a pressure of 20 to 60 kPa and a rotational speed of 350 rpm or less, and inorganic particles having an abrasive grain size of 0.020 to 0.10 μm are used as abrasive grains.

Under condition (i) above, the current density is preferably 15 to 20 mA/cm ² . Further, the pH of the electrolytic solution is preferably 11 to 11.5.

The rotational speed of the polishing condition can be 50 to 350 rpm. As the abrasive grains, inorganic particles are used, and the inorganic particles are not particularly limited, but examples thereof include Colloidal SiO ₂ and the like.

The inner surface of the container wall 20 subjected to such polishing treatment can have a surface roughness Ra of 0.8 to 1.1 μm.

In addition, the "container wall" is a concept including not only the side wall but also the bottom wall. In other words, when the vaporized raw material is introduced into the vaporized raw material container 100, the wall portion with which the vaporized raw material comes into contact can be called the container wall.

Reference numerals 11 and 41 in FIG. 1 denote valves for opening and closing the flow path of the evaporation source container 100 . By opening the valves 11 and 41 , the carrier gas can be introduced into the evaporation source container 100 (inside the container body 10 ), and the mixed gas with the carrier gas can be led out of the container body 10 . Thus, the evaporation source container of the present invention can be provided with two or more on-off valves.

Here, the position of the inner surface of the vessel wall 10 made of nickel alloy, aluminum, aluminum alloy, or super stainless steel is not particularly limited, but at least when the evaporation source is put into the evaporation source container 100 It is preferable that the portion in contact with the evaporated raw material has the above configuration. Specifically, it can be a bottom wall and part of a side wall extending from the bottom wall (a part continuous with the bottom wall). Note that the entire container wall 10 may be made of nickel alloy, aluminum, aluminum alloy, or super stainless steel.

Other portions of the container wall 10 (portions other than the portion made of nickel alloy, aluminum, aluminum alloy, or super stainless steel) may be made of stainless steel, for example.

That is, the container wall 10 may consist of a single layer (wall) made of nickel alloy, aluminum, aluminum alloy, or super stainless steel, or may consist of a plurality of layers (walls). When it consists of a plurality of layers, at least part of the innermost layer may be made of nickel alloy, aluminum, aluminum alloy, or super stainless steel. Other layers may be made of, for example, stainless steel.

In the container body 10 of the evaporation source container 100, the total amount of metal impurities in the evaporation source when measured under the following condition (A) is preferably less than 200 ppb. Here, specifically, 20 kinds of elements shown in Table 2 correspond to "metal impurities".

Condition (A) is as follows. A solid or liquid compound (evaporation raw material) is filled in the container body of the evaporation raw material container, and then the container body is monitored in the range of room temperature to 200 ° C. using a heating means such as an external heater, 24 heat for an hour. After that, the compound (evaporation raw material) in the container body of the evaporation raw material container is sublimated and recovered. Then, a predetermined amount of the recovered material is dissolved with aqua regia using an ICPMS (inductively coupled plasma mass spectrometry) apparatus. After that, it is heated to 120° C. by a heating means such as a hot plate to evaporate to dryness. Then, the evaporated to dryness is diluted to obtain a measurement sample. After that, the metal impurities in the measurement sample are measured by the analysis device.

The container body 10 may be provided with the lid 31 and the receiver 32 (having a separable structure) as described above, or the lid 31 and the receiver 32 may be integrated. There may be.

Carrier gases are not particularly limited, and examples include hydrogen, helium, nitrogen, oxygen, argon, carbon monoxide, and carbon dioxide.

The vapor source is not particularly limited, and for example, those used for film formation by a chemical vapor deposition (CVD) method, a metalorganic chemical vapor deposition (MOCVD) method, an atomic layer deposition (ALD) method, etc. are appropriately determined. There are no restrictions on solids and liquids as long as they have volatility. More specifically, tertiary amylimido tris(dimethylamido) tantalum (thymata), tetrakis(diethylamido)titanium (TDEAT), tetrakis(dimethylamido)titanium (TDMAT), dimethylamide tantalum pentaphosphate (PDMAT), tantalum pentaethoxy (TAETO), bis(ethylcyclopentadienyl)ruthenium (II) (Ru(EtCp) ₂ ).

Further, evaporation raw materials include, for example, boron, phosphorous acid, copper, gallium, arsenic, ruthenium, indium, antimony, lanthanum, tantalum, iridium, decaborane (B ₁₀ H ₁₄ ), hafnium tetrachloride (HfCl ₄ ), Zirconium chloride ( _ZrCl4 ), Indium trichloride ( _InCl3 ), Gallium tetrachloride, Tungsten hexachloride, Tungsten pentachloride, β-diketonate complex, Cyclopentadienylcycloheptatrienyl titanium (CpTiChT), Aluminum trichloride (AlCl ₃ ), titanium iodide (TixIy), cyclooctatetraenecyclopentadienyl titanium ((Cot)(Cp)Ti), bis(cyclopentadienyl)titanium diazide, tungsten carbonyl (Wx(CO)y), bis( Cyclopentadienyl)ruthenium (II) (Ru(Cp) ₂ ), ruthenium trichloride (RuCl ₃ ) and other solid raw materials can be mentioned.

In addition, the evaporation source container of the present invention can satisfactorily store even highly corrosive evaporation sources such as chlorides such as zirconium chloride and aluminum chloride. becomes very small.

The evaporation source container of the present invention is a container that can keep the compound in either a gaseous or solid state by coming into contact with a heating medium or a cooling medium that can be heated or cooled from the outside. be.

The evaporation source container of the present invention is for storing the evaporation source used for film formation by the chemical vapor deposition (CVD) method, the metal organic chemical vapor deposition (MOCVD) method, and the atomic layer deposition (ALD) method. It can be used as a container, and is preferably used as a container used for film formation by an atomic layer deposition (ALD) method. Specifically, the atomic layer deposition (ALD) method is a method capable of forming a film thinner than a film formed by a chemical vapor deposition (CVD) method, and a very thin film of about several nanometers can be formed. It is possible to form a film, but on the other hand, the accuracy of the film is easily affected by impurities contained in the evaporated raw material. Therefore, by using the evaporation source container of the present invention, the amount of impurities contained in the evaporation source can be minimized.

[2] Method for manufacturing evaporation raw material container:
The evaporation source container of the present invention can be manufactured as follows. First, an outer wall (outer container) made of stainless steel is produced by a conventionally known method. After that, an inner wall (inner container) made of nickel alloy, aluminum, aluminum alloy, or super stainless steel is produced. At this time, the inner container should be of a size that can be accommodated in the outer container without gaps. Then, the inner wall is accommodated within the outer wall to produce a container material. Similarly, a lid is also produced. Thus, a container having an untreated container body is obtained (preparation step).

Next, the untreated container body is polished (polishing process). Specifically, the inner surface of the untreated container body is polished under the condition (i) described above to obtain a polished container body. In this manner, the evaporation source container 100 can be produced.

[3] How to use the evaporation source container:
First, the carrier gas inlet 12 of the evaporation source container 100 is connected to a carrier gas tank (not shown), and the mixed gas outlet 42 is connected to semiconductor processing equipment (not shown). Next, the vaporized raw material is put into the vaporized raw material container 100, and then the container main body 10 is sealed. Next, a carrier gas is introduced into the evaporation source container 100 from the carrier gas tank. Then, the evaporation source (source gas) evaporated in the evaporation source container 100 is mixed with the carrier gas, and the mixed gas is discharged from the mixed gas outlet port 42 . Note that the evaporation raw material is evaporated (vaporized) by heating or the like to become a raw material gas. Then, in a semiconductor processing facility, film formation is performed by a chemical vapor deposition (CVD) method, a metal organic chemical vapor deposition (MOCVD) method, or an atomic layer deposition (ALD) method. A semiconductor processing facility is a facility (for example, a reaction chamber of a CVD apparatus) in which a substrate to be coated is placed, and a desired thin film is formed on the substrate placed in the semiconductor processing facility.

Since the container wall 20 of the container main body 10 has the above structure, the evaporation source container 100 is excellent in corrosion resistance. As a result, the proportion of impurities derived from the container in the vaporized material becomes very small, and a high-purity mixed gas can be supplied to the semiconductor processing equipment. The evaporation source container of the present invention is a container for gasification as a gas phase for CVD, ALD, MOCVD, etc., and is used as a pressure container equipped with a valve for semiconductors.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these.

(Examples 1 to 11, Comparative Examples 1 to 18)
A container (cylindrical container with a lid and a bottom) such as the evaporation source container 100 shown in FIGS. 1 and 2 was produced. Specifically, using each material shown in Table 1 (described in the columns of "inner wall" and "outer wall" of "container wall"), a "cylindrical container with a lid and a bottom" was produced, and this The inner surface of the container was polished under the following condition (i) to obtain each evaporation source container.
Condition (i):
An electrode with a diameter of 300 mm was used, the current density was 20 mA/cm ² or less, the concentration of the electrolytic solution was 20% by mass, the liquid flow rate was 3 L/min, the pH of the electrolytic solution was 10, and the polishing conditions were pressure 31.0. The pressure is 35 kPa, the rotation speed is 300 rpm, and Colloidal SiO ₂ with an abrasive grain size of 0.07 μm is used as abrasive grains.

Corrosion resistance was evaluated for this evaporation source container. The thickness of the inner wall of the main body of the evaporation source container was 3 mm, and the thickness of the outer wall was 3 mm. Furthermore, the internal diameter of the inner container was 140 mm.

Specifically, the evaluation of the corrosion resistance is performed by putting the evaporation material into each evaporation material container of Examples and Comparative Examples, and measuring the amount of impurities (20 kinds of elements shown in Table 2) in the evaporation material after heat treatment. was measured by ICPMS (inductively coupled plasma mass spectrometer). Aluminum chloride was used as the evaporation material.

Specifically, the measurement of the amount of impurities was performed under the following conditions (A). First, the container main body of the evaporation source container was filled with the evaporation source, and then the container main body was heated in the range of room temperature to 200° C. using an external heater for 24 hours while monitoring. After that, the evaporation raw material in the container body of the evaporation raw material container is sublimated and recovered, and the recovered material is dissolved in a predetermined amount using aqua regia using an ICPMS (inductively coupled plasma mass spectrometry) device. let me It was then heated to 120° C. on a hot plate and evaporated to dryness. Then, the evaporated to dryness was diluted to obtain a measurement sample. After that, the metal impurities in the measurement sample were measured with the above-described analyzer. The total amount of metal impurities (20 kinds of elements shown in Table 2) in the evaporation raw material measured under condition (A) was less than 200 ppb in all of Examples 1 to 11.

Moreover, as "Hastelloy", specifically, "Hastelloy C276" was used. As "Inconel", specifically, "Inconel 600" was used. As the "aluminum alloy", specifically, "aluminum alloy A5052" was used. As the "stainless steel", specifically, "SUS316L" was used. As "super stainless", specifically, Ni is 17.98% by mass, Cr is 20.19% by mass, Mo is 6.26% by mass, N is 0.22% by mass, and Cu is 0.67% by mass. %, and further containing 0.014% by mass of C, 0.55% by mass of Si, 0.57% by mass of Mn, 0.017% by mass of P, and 0.001% by mass of S.

Further, the surface roughness of the inner surface of the container body 10 before and after the heating was measured with an AFM (atomic force microscope) analyzer (manufactured by HORIBA). This surface roughness was measured multiple times and the average value was calculated.

As can be seen from Table 2, the evaporation source containers of Examples 1-11 contained less impurities than the evaporation source containers of Comparative Examples 1-18. Also, it can be seen that the difference in surface roughness before and after the corrosion resistance test is small. Here, the fact that the difference in surface roughness is small means that the degree of corrosion due to the vaporized material is small, and it can be seen that the corrosion resistance is high. From these results, it can be seen that the evaporation source containers of Examples 1 to 11 are excellent in corrosion resistance.

The vapor source container of the present invention can be used as a container for film formation by a chemical vapor deposition (CVD) method, a metal organic chemical vapor deposition (MOCVD) method, or an atomic layer deposition (ALD) method.

10: container body, 11, 41: valve, 12: carrier gas inlet, 20: container wall, 21: outer wall, 23: inner wall, 31: lid, 32: receiver, 42: mixed gas outlet, 100: Container for evaporation raw materials.

Claims (1)

a sealable container body having a thermally conductive container wall;
a carrier gas introduction port for introducing a carrier gas into the container body;
A method for manufacturing an evaporative raw material container comprising: a mixed gas outlet for discharging a mixed gas of the evaporative raw material and the carrier gas in the container main body to the outside of the container main body,
a preparation step of providing a sealable green container body having a thermally conductive container wall;
a polishing step of polishing the inner surface of the untreated container body under the following condition (i) to obtain the polished container body.
Condition (i):
Using an electrode with a diameter of 250 to 350 mm, a current density of 28.5 mA/cm ² or less, an electrolytic solution concentration of 15 to 30% by mass, a liquid flow rate of 1 to 8 L/min, an electrolytic solution pH alkaline, and Polishing conditions are a pressure of 20 to 60 kPa and a rotational speed of 350 rpm or less, and inorganic particles having an abrasive grain size of 0.020 to 0.10 μm are used as abrasive grains.

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