JP3500266B2 - Components for semiconductor manufacturing process - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to components applied to various apparatuses for semiconductor manufacturing processes, and more particularly to an oxidation furnace, a CVD apparatus, an epitaxial growth apparatus, an ion implantation apparatus, a diffusion furnace, and a reactivity applied to a dry process. The present invention relates to a semiconductor manufacturing process member applicable to an ion etching apparatus, a plasma etching apparatus, and pipes, air supply / exhaust fans, vacuum pumps, valves and the like attached to these apparatuses.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, since harmful gas such as fluoride and chloride and an aqueous solution are handled in each step, there is a problem that materials constituting the process are seriously corroded and worn.

In particular, a semiconductor device is made of metal S as its material.
A compound semiconductor mainly made of i, Ga, As, P, etc. is mainly used, and the basic steps of its production are composed of a film forming process, an impurity injection process, an etching process, an ashing process, a cleaning process and the like. Further, most of these main processes are so-called dry processes which are processed in vacuum or reduced pressure.

As an apparatus belonging to this dry process,
Chemical Vapor Depositi in oxidizing furnace under atmospheric pressure and decompression
There are an on (CVD) device, an epitaxial growth device, an ion implantation device, a diffusion furnace, a reactive ion etching device, a plasma etching device and piping attached to these devices, a supply / exhaust fan, a vacuum pump, valves and the like.

The corrosive gas species handled by these devices are as follows. _{Fluoride: BF 3, PF 3, PF} 6, NF 3, WF 3, HF _{chloride: BCl 3, PCl 3, PCl} 5, POCl 3, As
Cl ₃ , SnCl ₄ TiCl ₄ , SiH ₂ Cl ₂ , SiC
l ₄ , HCl, Cl ₂ Bromide: HBr Others: H ₂ S, NH ₃

In the dry process using these halides, plasma (to be exact, low temperature plasma) is often used in order to further activate the reaction, but in the plasma environment, the halogen compound is ionized and extremely corroded. In addition to atomically strong F, Cl, Br, I, etc.,
Fine powdery solids such as SiO ₂ , Si ₃ N ₄ , Si and W are newly formed in the gas phase. For this reason, the devices having a rotating function such as the air supply / exhaust fan and the vacuum pump and the members thereof are further damaged by corrosion and erosion.

[0007] As a countermeasure against corrosion of various devices and their associated members in the dry process as described above, coating with fluorine-based or epoxy-based resin paint, nickel plating,
Surface treatment such as nitriding is applied.

[0008]

However, the coatings with the fluororesin-based and epoxy-based resin paints, which are used as measures against corrosion occurring in various devices in the dry process, are easily deteriorated by the atomic halogen element. Lose its function. Further, although the nickel plating film has corrosion resistance as compared with carbon steel and cast iron, the presence of pinholes peculiar to the plating film often corrodes the base material under the plating film and often causes the plating film to peel off.

Further, fine powdery solids such as SiO ₂ , Si ₃ N ₄ , Si and W, which are easily generated in a plasma CVD environment, mechanically damage the air supply / exhaust fan, vacuum pump and valves. , This effective countermeasure technology has not been established either.

The present invention is directed to various devices used in semiconductor manufacturing processes, particularly dry processes, and halogen compounds (including atomic compounds) generated in supply / exhaust fans as auxiliary devices, vacuum pumps, pipes, valves and the like. It is an object of the present invention to provide a material having high durability against corrosion and erosion damage caused by fine powdery solid substances such as halogen) and SiO ₂ , Si ₃ N ₄ , Si and W.

[0011]

In order to solve the above technical problems, the present invention employs the following means. That is, according to claim 1 invention forms an intermetallic compound produced in the aluminum diffusion layer <br/> table surface of the metal Seimoto material, the aluminum concentration of the aluminum diffusion layer
It is a member for a semiconductor manufacturing process characterized by improving the halogen compound resistance and the blast erosion resistance as 15 to 45 wt% . According to claim 2,
Akira, the metal base material is carbon steel, Cr steel, Ni-Cr
Contracts characterized by steel, Ni-based alloys, cast iron, cast steel
The member for semiconductor manufacturing process according to claim 1.

In such a structure, the coating having the aluminum diffusion layer is metallurgically bonded to the base material and hardened, so that it is not peeled off even if it receives a mechanical shock. Further, the aluminum diffusion layer forms intermetallic compounds such as FeAl _x , NiAl _x , and CoAl _x depending on the type of base material. These compounds are hard and have excellent erosion resistance, and at the same time, halogen containing an atomic halogen element is used. It also exerts strong chemical resistance to compounds. Further, these intermetallic compounds also have excellent sputtering resistance in a plasma environment, and can extend the life of the substrate.

[0013] According to a third aspect of the invention, A aluminum of the aluminum diffusion layer, the reaction between the metal substrate
From Fe ₃ Al, FeAl, FeAl ₂ , FeAl ₃ , N
iAl ₃ , Ni ₂ Al ₃ , NiAl, Ni ₃ Al, Co ₂ A
l ₉ , Co ₄ Al ₁₂ , Co ₂ Al ₅ , CoAl, CrA
l ₇ , Cr ₂ Al ₁₁ , Cr ₄ Al ₉ , Cr ₅ Al ₈ , Cr ₂ A
2. The semiconductor manufacturing process member according to claim 1, wherein the member comprises at least one kind of intermetallic compound selected from the group consisting of l. If Al is less than 15 wt%, the corrosion resistance is poor. It is technically difficult to form a diffusion layer of 45 wt% or more.

[0014] the previous Symbol industrial aluminum or silicon containing aluminum diffusion layer is the inevitable impurities 2~12wt
Tsu der those treated by% including aluminum alloy
May be .

[0015] Before SL preform is a high-carbon metal material, after decarburization of the surface, to form the aluminum diffusion layer
Good . Thereby, when the member to be treated has graphite such as cast iron, the object of the present invention is achieved by performing a coating treatment having an aluminum diffusion layer after decarburizing the surface, if necessary. be able to.

The invention according to claim 5 is characterized in that a metal aluminum layer and an aluminum oxide layer are further formed on the surface layer of the aluminum diffusion layer, for the semiconductor manufacturing process according to any one of claims 1 to 4. It is a member.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Specific technical means for carrying out the present invention and the function of the aluminum diffusion layer obtained by this method will be described.

(1) Surface Treatment Method for Forming Aluminum Diffusion Layer Metal A on a metal substrate by a thermal spraying method using a heat source such as electric arc, flammable gas combustion flame, gas plasma
After forming the film of 1 l, this is heated at a temperature of 660 ° C. or higher of the melting point of Al for 0.5 to 3 hours (spray diffusion method). After a metallic base material is placed in a vacuum container, metal Al is evaporated by an electron beam and a film is formed on the surface of the base material, and this is subjected to the same heat treatment in a vacuum container or in the atmosphere (PVD method). . Metal Al powder or Al-Ni, Al-Fe, Al
In a mixed powder of Al ₂ O ₃ and Al alloy powder such as —Cr and Al—Co, 0.5 to 3% of ammonium chloride (NH ₄ C
l) is added, and the metal base material is embedded in this, and then 660-1000 while flowing argon gas or hydrogen gas.
Heat at a temperature of 0.5 ° C. for 0.5 to 10 hours (powder diffusion method). After the Al or Al-Si alloy is heated and melted, the metal base material is dipped in this to form a film having an Al diffusion layer. When hot-dip Al plating is performed on stainless steel or Ni-based alloy, an alloy layer having a high Al concentration is formed. This alloy layer is brittle, but heat treated, eg 7
It is convenient to heat in an electric furnace at 00 to 950 ° C. for 0.5 to 3 hours because the Al concentration is reduced and brittleness disappears.
When the Al-Si alloy is used, the amount of Si increases to some extent in the Al diffusion layer, but if the amount of Si is less than 2 to 12 wt%,
It does not hinder the object of the present invention (hot dip Al plating method,
Melting method).

(2) Action of Aluminum Diffusion Layer In the treated layer obtained by the above method,
By the metallurgical reaction of all the base material components and Al, an Al diffusion layer firmly adhered to the base material is formed. In the powder diffusion method, all of the treated layers are composed of Al diffusion layers, and the spray diffusion method,
In the PVD method and the hot dip Al plating method, metallic Al may remain on the Al diffusion layer depending on the heat treatment conditions, but an Al ₂ O ₃ film is also formed on the surface of this metallic Al layer, and this film also has corrosion resistance. Since it works, it is not necessary to remove the metal Al layer.

FIG. 1 shows the A obtained by the method of the present invention.
1 shows a cross section of a treatment layer having an l diffusion layer. In the figure, (a) is a treatment layer obtained by a thermal spray diffusion method, PVD method and hot dip Al plating method, and (b) is a representative treatment layer obtained by a powder diffusion method. In the figure, 1 is a metallic substrate, 2 is an Al diffusion layer, 3 is a metallic Al layer, 4 is Al
_{It is a 2} O ₃ layer.

As the metal base material used for the purpose of the present invention, any material which shows a metallurgical reaction with Al, such as carbon steel, Cr steel, Ni-Cr steel, Ni-base alloy, cast iron and cast steel, may be used. You can A material having graphite, such as cast iron, has a temperature of 800 to 900 ° C. and 0.5 to
When the heat treatment is performed for 5 hours to remove the graphite, an Al diffusion layer having more excellent corrosion resistance can be obtained.

The intermetallic compound produced in the Al diffusion layer differs in the metallic base material component depending on the type, but in general, Fe-based components: Fe ₃ Al, FeAl, FeAl ₂ , FeA.
l ₃ Ni-based component: NiAl ₃ , Ni ₂ Al ₃ , NiAl, Ni ₃
Al ₂ Co-based components: Co ₂ Al ₉ , Co ₄ Al ₁₃ , Co ₂ Al ₅ ,
CoAl Cr-based components: CrAl ₇ , Cr ₂ Al ₁₁ , Cr ₄ Al ₉ , C
The main components are r ₅ Al ₈ and Cr ₂ Al. These intermetallic compounds have a characteristic that the erosion resistance is improved because the hardness increases as compared with the respective base materials.

In the present invention, the presence of a diffusion layer having an Al intermetallic compound is essential, but for quality control, the Al concentration in the diffusion layer should be defined regardless of the type of the intermetallic compound. It's enough. That is, although the Al concentration in the diffusion layer obtained by the diffusion method is in the range of 15 to 45 wt%, a strong resistance to corrosion and erosion of halogen compounds is exhibited. If Al is less than 15 wt%, the corrosion resistance is poor, and it is technically difficult to form a diffusion layer of 45 wt% or more. The concentration of the Al layer (4 in FIG. 1) formed by another processing method is not specified when the Al diffusion layer having the above concentration exists in the lower layer portion.

(Embodiment 1) In this embodiment, the corrosion resistance of a metal material subjected to a surface treatment having an Al diffusion layer of the present invention in a fluoride gas was compared with an untreated metal material. (1) Test piece of an example of the present invention Using each of the materials shown below as a base material, after finishing into a shape of width 20 x length 30 x thickness 3 mm, 850 ° C x by a powder diffusion method
Al diffusion treatment was performed for 8 hours. A obtained by this processing
Although the Al concentration of the outermost surface of the l diffusion layer varies depending on the material, it is in the range of 15 to 32%. Carbon steel (SS400) Flake graphite cast iron (FC200) Spheroidal graphite cast iron (FCD400) Chrome steel (SUS410) Stainless steel (SUS304) (2) Comparative test piece I tried it.

(3) Corrosion test device and corrosion conditions FIG. 2 shows the corrosion test device. After the test piece 21 is left standing on the installation table 26 inside the stainless steel pipe 23 provided in the center of the electric furnace 22, the corrosive gas 24 is flown from the left side. A quartz discharge tube 25 provided in the middle of the pipe is loaded with a microwave having an output of 600 W to promote the activation of the corrosive gas. The activated corrosive gas is introduced into the electric furnace, corrodes the test piece 21, and then is discharged from the right side to the outside of the system. A test piece temperature of 18
0 ° C, corrosive gas CF ₄ 150 ml / min, O ₂ 75
A corrosion test was conducted for 10 hours while flowing ml / min. (4) Corrosion test results Table 1 shows the corrosion test results. As is clear from this result, the test pieces of Comparative Examples (Nos. 6 to 10) each had a large amount of corrosion and a reduction of 3 to 23 mg / cm ² was observed. In particular, carbon steel and cast iron have a large corrosion weight loss, and Cr steel and stainless steel have a relatively small weight loss. In contrast, the Al of the present invention
The test piece having the diffusion layer has a corrosion weight loss of 1.1 to 9 mg / cm ²
It was confirmed that the corrosion resistance remained in the range of 10% and the excellent corrosion resistance was exhibited.

[Table 1]

Example 2 In this example, F was used as the base material.
Using cast iron containing graphite such as C200 and FCD400,
The surface of this was decarburized, and then surface-treated to form an Al diffusion layer. (1) Material and dimensions of test specimen Carbon steel (SS400) Flake graphite cast iron (FC200) Spheroidal graphite cast iron (FCD400) Chrome steel (SUS410) Stainless steel (SUS304) Specimen size is width 20 x length 30 × Thickness is 5 mm. (2) Decarburization treatment The decarburization of the test piece was performed by performing a heat treatment at 950 ° C for 10 hours in the atmosphere. (3) Same as Example 1 of surface treatment having Al diffusion layer (4) Corrosion test equipment and test conditions Same as Example 1

(5) Corrosion test results The results of measuring the amount of corrosion are shown in Table 2. 5 with FC200
~6mg / cm ^2, FCD400 and remained in the range of 5 to 6 mg / cm ^2, the further the corrosion resistance was improved compared to the results of Example 1 (Table 1). The reason for this is that when graphite is present, the carbon itself disappears as volatile CF ₄ due to atomic F dissociated from CF ₄ which is a corrosive gas, so that the base material directly below the graphite is left untreated, It is considered that the amount of corrosion and wear in this portion has increased. In the present invention, after removing the graphite exposed on the surface by decarburization treatment in advance, A
It is considered that the amount of corrosion is reduced as a result of the entire surface being covered with a film having good corrosion resistance because the surface treatment for providing the l diffusion layer is performed.

[Table 2]

Example 3 In this example, an Al film was formed on the surface of the base material by the thermal spray diffusion method and the PVD method, and then heated to diffuse into the base material. (1) A test piece having a width of 20 mm, a length of 30 mm, and a thickness of 5 mm, which had been subjected to the surface treatment of the present invention, was subjected to A under the following conditions.
A surface treatment layer having a diffusion layer was formed. After applying metal Al to a thickness of 50 μm by the arc spraying method, this was heat-treated in an electric furnace at 830 ° C. for 8 hours. In this treatment, the Al concentration in the Al diffusion layer is 15 to 27
%, and 93 to 96 wt% of metallic Al covered with the aluminum oxide film remained in the upper layer.

After forming an Al film with a thickness of 25 μm by the PVD method, heat treatment was performed at 830 ° C. for 5 hours in an electric furnace. In this process, the Al concentration in the Al diffusion layer is 1
5 to 25 wt%, and 98 to 99 wt% of metal Al covered with the aluminum oxide film remained in the upper layer portion.
The following materials were used as test materials for the base material. (A) Carbon steel (SS400) (b) Stainless steel (SUS304) (c) Ni-based alloy (15 wt% Cr-7 wt% Fe-2.
5wt% Ti-1wt% Nb-remaining Ni)

(2) Specimen of Comparative Example As a comparative example, untreated carbon steel, stainless steel and Ni-based alloy were used. (3) Corrosion test device and corrosion conditions The device shown in FIG. 2 was used as the corrosion test device, and the same conditions as in Example 2 were adopted as the corrosion conditions. (4) Test results Table 3 shows the corrosion test results. As is clear from this result, the test piece of the comparative example is subjected to severe corrosion damage and intergranular erosion, but the coating having the Al diffusion layer of the present invention has a small amount of corrosion, and an Al coating is formed by the thermal spraying method or the PVD method. After that, it was confirmed that sufficient corrosion resistance is exhibited even if a heat diffusion treatment is performed.

[Table 3]

Example 4 In this example, a corrosion resistant member having an Al diffusion layer of the present invention, which is suitable for use in an environment in which sputtering is performed in an argon gas containing a corrosive gas, was prepared. (1) A base material made of SUS304 having a width of 20 mm, a length of 50 mm, and a thickness of 3 mm, which had been subjected to the surface treatment of the present invention, was manufactured, and then an Al diffusion layer was formed by the powder diffusion method and the molten Al plating method. . The Al concentration in the Al diffusion layer obtained by the molten Al plating method was 25 to 35 wt%, and 5 wt% Si-Al was formed in the upper layer portion. These test pieces were attached to a target holding member for sputtering described later and a discharge port of a vacuum pump to perform a corrosion test.

(2) For comparison, SUS304 which was not surface-treated was used. (3) Corrosion test device and corrosion conditions As the corrosion test device, the sputtering device shown in FIG. 3 was used. In this apparatus, a target 32 and an object to be processed 33 are arranged in a vacuum container 31, both of which are connected to a DC power source 34 provided outside the vacuum container, the target 32 is a negative electrode, and the object to be processed 33 is a positive electrode. As a result, the voltage is applied between both poles. An inlet pipe 35 for supplying a corrosive gas or an argon gas is attached to the vacuum container 31, while a vacuum pump 36 can be used to discharge it to the outside of the system. In the test, a vacuum pump was connected to evacuate the air in the vacuum vessel, and the pressure was adjusted to 10 ^-2 torr with argon gas, while a DC voltage of ² kV was applied for sputtering. Aluminum was used as the target 32 and SUS304 was used as the object 33 to be processed. Also, as a corrosive gas, C together with argon gas
Sputtering was performed while continuously injecting 10 ppm of F ₄ and Cl ₂ each. 37 is aluminum particles, 3
Reference numeral 8 shows an environment in which argon gas is turned into plasma. The test members were attached to the target holder 39 and the vacuum pump outlet 40, respectively. The corrosiveness was evaluated by measuring the surface roughness before and after the test.

(4) Corrosion Test Results Table 4 shows the corrosion test results. As is clear from this result, the untreated test piece of the comparative example shows a relatively good corrosion resistance when sputtered with argon gas only, but CF
_{When 4} and Cl ₂ gas were mixed in, the surface roughness became 5 to 10 times. On the other hand, the coatings of the present invention each had a sputter resistance of 20 to 40% of that of the untreated test piece even if a corrosive gas was present. Also, the surface roughness of the test piece attached to the outlet of the vacuum pump shows almost the same tendency as the sputtering environment, and although it is not directly exposed to sputtering, it also has excellent corrosion resistance against corrosive gas activated in the sputtering atmosphere. It became clear that it would work.

[Table 4]

(Example 5) In this example, the erosion resistance of the coating film of the present invention containing an Al diffusion layer was investigated. (1) SUS304 and F having a width of 50 mm, a length of 100 mm, and a thickness of 5 mm, which have been subjected to the surface treatment of the present invention
A base material test piece made of C200 was subjected to a hot dip Al plating method and a powder diffusion method to form a film having an Al diffusion layer on the surface of the test piece. Hot-dip Al plating method: Al-2 wt% Immersed in molten Si alloy (660 ° C.) for 1 minute Powder diffusion method: Al-Fe alloy powder 40 wt%,
Al ₂ O ₃ powder 59 wt% NH ₄ Cl 1 wt
% Mixed powder was treated at 850 ° C. for 10 hours. (2) Test piece for comparison For comparison, untreated SUS304 and FC200 were used.

(3) Test method Japanese Industrial Standard JIS R6111 (artificial abrasive) WA ^#
Using a 60 Al ₂ O ₃ abrasive, a blast angle was 30 °, a blast pressure was 5 kgf / cm ² , and the test piece was continuously sprayed directly for 5 minutes, and the erosion resistance was evaluated from the weight before and after the test. (4) Test results Table 5 shows the test results. As is clear from this result,
The untreated test pieces (Nos. 5 and 6) have large changes in weight. That is, FC200 has 800 to 1200 mg / cm ² , SU
In S304, a film having the Al diffusion layer of the present invention (No. 1 to 4) for a weight loss of 300 to 400 mg / cm ^2.
Is FC200 510-710 mg / cm ² , SUS30
No. 4 was 180 to 270 mg / cm ² , and it was confirmed that the erosion resistance was excellent. Also melt A
The coatings obtained by the 1-plating method and the powder diffusion method exhibited good erosion resistance, and neither superiority nor inferiority was observed between them.

[Table 5]

[0036]

As described in the above examples, the treatment layer having the Al diffusion layer of the present invention not only exhibits high sputtering resistance and excellent corrosion resistance to a halogen compound excited by plasma, but also blasts. Excellent performance in erosion. The main cause of this is Al
This is considered to be due to the formation of an intermetallic compound by the metallurgical reaction between the base material and the base material component, and the corrosion resistance and good adhesion of the Al ₂ O ₃ film formed on the outermost surface layer thereof. The coating film of the present invention is relatively easy and inexpensive to manufacture, and can be processed with high precision even on a small screw member by selecting a processing method. Therefore, the apparatus for the semiconductor manufacturing process or the like, which is constituted by the corrosion resistant member of the present invention, can be stably operated for a long time, and it is expected that the productivity is improved and the apparatus life is extended to reduce the cost.

[Brief description of drawings]

FIG. 1 schematically shows the cross-sectional structure of a treated film of the present invention.

FIG. 2 shows an outline of a corrosion test apparatus using a gas containing a halogen compound.

FIG. 3 shows an outline of a sputtering apparatus.

[Explanation of symbols]

1 Base Material 2 Diffusion Layer Produced by Aluminum Penetrating into Base Material 3 Aluminum Layer 4 Al ₂ O ₃ (Aluminum Oxide Film) 21 Test Piece 22 Electric Furnace 23 Stainless Steel Tube 24 Corrosive Gas 25 Quartz Discharge Tube 26 Test Piece Installation Table 31 Vacuum container 32 Target 33 Object to be processed 34 DC power source 35 Argon gas introduction pipe 36 Vacuum pump 37 Al particles of target adhering to the surface of the object to be processed 38 Plasma generated by excitation of argon gas 39 Test attached to target support bracket Piece 40 Test piece attached to the vacuum pump outlet

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirokazu Takayama 11-1 Haneda-Asahi-cho, Ota-ku, Tokyo Inside the EBARA CORPORATION (72) Inventor Yoshihiro Niimura 11-1 Haneda-Asahi-cho, Ota-ku, Tokyo Stock company EBARA MFG. (72) Inventor Yoshio Harada 4-13-4 Fukaekita-cho, Higashinada-ku, Kobe-shi, Hyogo Prefecture Tokaro Corporation (72) Inventor Junichi Takeuchi 4-13 Fukae-kita-cho, Higashinada-ku, Kobe City, Hyogo No. 4 Tokaro Co., Ltd. (72) Inventor Katsuhisa Sugimoto 2-11-18 Kurita, Hitoshira-ku, Sendai-shi, Miyagi Prefecture (56) Reference JP-A-9-10577 (JP, A) JP-A-4-193966 ( JP, A) JP 60-63364 (JP, A) JP 57-19371 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23C 10/00-10/60 H01L 21/3065, 21/205

Claims (3)

(57) [Claims] 1. A aluminum diffusion layer on the front surface of the metal Seimoto material
In forming the resulting intermetallic compound, the aluminum expansion
The aluminum concentration in the layer is 15-45 wt% ,
A member for a semiconductor manufacturing process, which has improved resistance to halogen compounds and blast erosion resistance. 2. The metal base material is carbon steel, Cr steel, N
Characterized by i-Cr steel, Ni-based alloy, cast iron, cast steel
The member for semiconductor manufacturing process according to claim 1. 3. A aluminum of the aluminum diffusion layer is reacted with Fe ₃ Al and the metal substrate, FeA
1, FeAl ₂ , FeAl ₃ , NiAl ₃ , Ni ₂ Al ₃ ,
NiAl, Ni ₃ Al, Co ₂ Al ₉ , Co ₄ Al ₁₂ , Co
₂ Al ₅ , CoAl, CrAl ₇ , Cr ₂ Al ₁₁ , Cr ₄ A
The member for semiconductor manufacturing process according to claim 1, which comprises at least one intermetallic compound selected from the group consisting of l ₉ , Cr ₅ Al ₈ , and Cr ₂ Al.