JP2003175452A - Method of polishing inner face of stainless pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for removing chemically and completely residual iron powder and rust generated in polishing and left after the polishing, without roughening a pipe surface, when polishing an inner face of a stainless steel pipe for a semiconductor device by a magnetic force beam, in particular, when polishing the inner face of flexible one. <P>SOLUTION: In this method for polishing the stainless steel pipe by magnetic force beam work, and for removing chemically the residual iron powder and rust generated in the polishing and left after the polishing, a passivated film is formed at first by conducting washing by a weak acid solution non-corrosive on stainless steel, and washing using a strong acid is carried out thereafter to dissolve completely the residual iron powder and rust. The polishing of the stainless steel pipe by the magnetic force beam work is the polishing of the inner face for the flexible pipe, the weak acid solution non-corrosive on the stainless steel used at first is nitric acid solution, and the strong acid used thereafter to dissolve completely the residual iron powder and rust is Stain-Pet (R) solution. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for chemically removing residual iron powder or rust generated after polishing in the inner surface polishing of a stainless steel pipe for a semiconductor device by a magnetic force line beam, particularly in the inner surface polishing of a flexible pipe.

[0002]

2. Description of the Related Art Since semiconductor devices are provided with pipes for various gases and the like, and semiconductor manufacturing devices severely dislike the mixing of impurities, it is necessary to polish the inner surface of the stainless pipe used for the pipes to a high quality. At the same time, thorough cleaning is required to prevent impurities from remaining after polishing. That is, the inner surface of the pipe is formed with a large number of micron-order minute projections in the molding process, and if foreign matter or gas is adsorbed to the projections, the impurities will be mixed in. Needs to be well polished. In particular, in the case of a flexible portion, it is difficult to mold due to the unevenness, and therefore the smoothness of the surface is not sufficient. Therefore, it is particularly necessary to polish the surface with high accuracy. However, as compared with an ordinary pipe, it is difficult to polish the surface with high accuracy due to the unevenness.

Therefore, the same applicant arranged one magnet on the outside of a member made of a non-magnetic material and having its inner surface treated, and supplying magnetic particles and slurry-like abrasive particles to the inner surface of the member, A method for surface treatment of the inner surface of the member which rotates at least one of the magnets and at the same time moves the magnets in the axial direction, or a plurality of sets of magnet driving motors and magnetic pole units installed on the inclined surface, and positioning attached to each magnetic pole unit A member, a pipe driving motor attached to the tip of the robot arm, a guide pipe penetrating the magnetic pole units and the positioning member and connected to the pipe driving motor, and a flexible member inserted in the guide pipe. A surface treatment device for the inner surface of a member has been proposed which includes a tube and magnetic particles and slurry-like abrasive particles filled in the flexible tube. There. (Japanese Patent Application No. 2001-2887
See 93. Hereinafter, this is referred to as magnetic field beam processing. ) Hereinafter, the outline is shown in FIGS.

In FIG. 1, the surface treatment apparatus 4 proposed above is used.
Includes a robot 5 and a support base 6, a guide pipe 9 made of a non-magnetic material is fixed to the support base 6 by a fixture 7, and a flexible pipe 1 made of a non-magnetic material in the guide pipe 9 (shown in FIG. 2). Is inserted and supported. The arm 5a of the robot 5 is freely movable in a three-dimensional space by an internal mechanism.

An abrasive grain tank 10 is disposed below the support table 6. The abrasive grain tank 10 is filled with slurry abrasive grains 11 in which oil is mixed with abrasive grains such as diamond, alumina oxide, and silicon nitride. Further, a supply nozzle 12 is arranged above the guide pipe 9, and the abrasive grain tank 1 is provided via an opening / closing valve 13, a supply pipe 14 and a pump 15.
It is connected within 0.

A frame 17 of a magnetic pole unit 16 is attached to the arm 5a of the robot 5, and the magnetic pole unit 1
Reference numeral 6 is movable along the guide pipe 9. A positioning member 19 that supports the guide pipe 9 is provided on the frame 17, and a roller 19a is provided at the tip of the positioning member 19 to support the guide pipe 9. The positioning member 19 maintains a gap between the magnet 23 (described later) and the guide pipe 9.

Next, the magnetic pole unit 16 will be described with reference to FIG. The magnetic pole unit 16 includes a frame 17, a magnet driving motor 20 and a supporting member 21 mounted on the frame 17, a cylindrical rotating member 22 rotatably provided on the supporting member 21, and an inside of the rotating member 22. Magnet 23 and balancer 2 fixed so as to face each other
4 between the drive pulley 25 fixed to the rotary shaft 20a of the motor 20 and the rotary member 22.
Is stretched. The rotating member 22 and the balancer 24 are made of a non-magnetic material. The guide pipe 9 is arranged at the center of the rotating member 22.

As shown in FIG. 3 (A), the magnet 23 is arranged such that the N pole and the S pole are located in the axial direction of the flexible tube 1, and in the flexible tube 1, iron, nickel, special treatment is carried out. The powdery or columnar magnetic particles 27 made of a magnetic material such as stainless steel are inserted. The size of the magnetic particles 27 is preferably 0.1 to 1.5 mm. Figure 3 (B)
As shown in FIG. 5, the magnetic field lines are laid down on the tube wall of the flexible tube 1 and the rate of change of the magnetic field is large.
Will be strongly adhered continuously along the valley portion 1a and the ridge portion 1b of the flexible tube 1.

Next, a surface treatment method of the surface treatment apparatus having the above structure will be described. After inserting the flexible pipe 1 into the guide pipe 9, mount the guide pipe 9 on the support base 6
Set to. Next, as shown in FIG. 3 (A), the magnetic particles 27 are inserted into the flexible tube 1, and the slurry abrasive particles 1 are introduced into the flexible tube 1 from the supply nozzle 12.
1 is supplied and the magnet 23 is rotated around the flexible tube 1 by the magnet driving motor 20 (rotation speed 1400r.
pm) and the slurry-like abrasive particles carried between the magnetic particles 27 and the magnetic particles slide on the valleys 1a and the peaks 1b of the flexible tube 1, and the slurry-like abrasive particles cause the valleys 1a to move.
And the surface of the mountain portion 1b is polished. At the same time, when the robot 23 vibrates the magnet 23 in the axial direction of the flexible tube 1 at a very small speed (arrow in FIG. 1), the magnetic particles 27 move from the valley portion 1a to the mountain portion 1b, as shown in FIG. Further, it can be polished with high precision. When the polishing of the portion is completed in this way, the magnetic pole unit 16 is moved by the robot 5 and the polishing is sequentially performed. Thus, the surface roughness before polishing was about Ry 4 μm, but after polishing, the surface roughness was about Ry 0.3 μm.

FIG. 5 is a diagram showing another embodiment of the surface treatment method of the present invention. In this embodiment, the magnetic poles N and S of the magnet 23 are arranged so as to be inclined with respect to the axis of the flexible tube 1. As a result, the magnetic particles 27 are attached to the tube wall while being inclined with respect to the axis of the flexible tube 1, so that the intermediate portion 1c between the valley portion 1a and the crest portion 1b can be polished with higher accuracy.

However, since iron powder is used as magnetic particles in the above-described magnetic force beam processing, the iron powder remains after polishing, and rust is partially generated, which must be completely removed to remain. Iron powder and rust itself become impurities. Therefore, conventionally, in order to remove the residual iron powder and rust inside, the stainless pipe after polishing was washed with a strong acid solution such as STEMPET solution (trademark) that completely dissolves the iron powder and the like. However, strong acid solutions such as the above-mentioned Stentet Solution (trademark) for stainless steel remove iron powder and rust, but they also violate the surface of stainless steel pipes that have been polished to a high quality, and the surface roughness measurement device There was no change, but the surface became a cloudy surface from the original glossy surface, and the surface layer was roughened. Therefore, there is a drawback that the commercial value is lowered.

The use of magnetic polishing as a conventional method for polishing the inner surface of a pipe is disclosed in JP-A-60-191759.
It is publicly known as disclosed in JP-A No. 63-221965, JP-A No. 7-40226, and JP-A No. 6-328360.

[0013]

DISCLOSURE OF THE INVENTION The present invention is intended for the inner surface polishing of a stainless steel pipe for a semiconductor device by a beam of magnetic force lines, particularly for the inner surface polishing of a flexible pipe, without ruining the pipe surface by residual iron powder or rust after polishing.
Moreover, it is an object of the present invention to provide a method for completely chemically removing it.

[0014]

In order to achieve the above object, a method of polishing the stainless pipe of the present invention by magnetic field beam processing and chemically removing residual iron powder and rust after the polishing is first described. It is characterized in that it is washed with a weak acid solution that does not violate stainless steel to form a passivation film, and then washed with a strong acid solution that dissolves all iron powder and rust.

Further, the polishing of the stainless pipe by magnetic field beam processing is the inner surface polishing of the flexible pipe, and the weak acid solution that does not violate the stainless steel used for the first cleaning is nitric acid, and the iron powder and rust used thereafter are not used. It is characterized in that the strong acid solution that completely dissolves is STEMPET solution (trademark).

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The inner surface of the flexible pipe or the like is polished by the conventional method. When the inner surface of the flexible pipe is polished by the magnetic field beam processing, the inner surface of the pipe is polished to a surface roughness of about Ry 0.3 μm as described above. This precision is a very excellent polishing method because it can be uniformly polished regardless of the peaks and valleys of the flexible pipe, and there is no other method for polishing the inner surface of the flexible pipe.

However, since the magnetic field beam processing uses iron powder as magnetic abrasive grains, a post-treatment for removing the iron powder and rust after polishing is necessary. FIG. 6 shows a structural diagram of an acid treatment device for removing foreign matter such as iron powder and rust. In FIG. 6, the acid solution 32 is filled in the container 38. An ultrasonic oscillator 37 is provided on the bottom of the container 38 to vibrate the acid solution 32. A heater 34 is provided on the side surface of the container to heat the acid solution 32. A motor 35 is provided above the container, and a storage support rod 33 of a flexible pipe is hung from the tip of the rotary shaft of the motor. FIG. 7 shows a top view of the container 38 seen from above, and a plurality of flexible pipes 31 are housed in a pipe support frame 39. The ultrasonic vibration is applied to the acid liquid 32 as described above, and at the same time, the pipe 36 is vertically rocked by the crank 36 of the motor 35. Thus, the outer surface of the pipe and the inner surface of the pipe are cleaned with the acid solution, and foreign substances such as iron powder and rust in the pipe 31 are dissolved and removed.

In the case of a flexible pipe, the step of washing the pipe as shown in FIG. 8 in a slanting manner is performed independently or in combination with the step of FIG. 8, the same components as those in FIG. 6 are designated by the same reference numerals. The difference from FIG. 6 is that a new motor 40 is provided and the flexible pipe 31 in the container is slowly rotated by the motor 40. Since air pools are likely to occur in the uneven portion in the flexible pipe and cleaning with acid solution is not performed when the air pools occur, the configuration of FIG. 8 is a device for eliminating such uncleaned portions. .

As mentioned above, a STEMPET solution (trademark) has been conventionally used as the acid solution for removing such residual iron powder. The STEMPET solution (trademark) is a mill scale (fuel rust) remover exclusively for immersion of stainless steel manufactured and sold by Fuji Giken Kogyo Co., Ltd., and has the following composition and characteristics.・ Main constituents Nitric acid (HNO ₃ ) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 48.0% Hydrogen fluoride (HF) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 4.0% Acidic aluminum fluoride (NH ₄ HF ₂ ) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 4.8% ・ Physical data Appearance ・ ・ ・ ・ Colorless boiling point ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ 121 ℃ Melting Point ・ ・ ・ ・ 33 ℃・ ・ 1.250 Vapor pressure ・ ・ ・ 15.0mmHg (20 ℃) Odor ・ ・ Nitric acid odor Solubility in water: 100% However, as mentioned above, strong acid solutions such as the above-mentioned Stentet Solution (trademark) for stainless steel remove iron powder and rust. Yes, but high-quality polished stainless steel Type surface also will commit, but there is no change on the surface roughness measuring instrument numerical have ended up with cloudy surface from the surface with a natural glossy surface, it was found that Mau roughened surface layer.

On the other hand, as a result of the experiment, it was washed with a weak acid solution (20% nitric acid) which did not violate the stainless steel.
It was also found that after the nitric acid treatment, the iron powder and rust remained after the nitric acid treatment, and the surface was not cleaned properly. Therefore,
The inventor, after polishing the stainless pipe by magnetic field beam processing, combines the step of cleaning with a weak acid solution that does not violate the stainless steel, and then cleaning with a strong acid solution that dissolves all iron powder. It was devised to be used for the method of chemically removing residual iron powder and rust afterwards.

The results are shown in FIGS. 9 (c) to 9 (e). When the above-mentioned nitric acid-treated stainless steel was immersed in the Stentet solution, the residual iron powder started to dissolve after 2 minutes (Fig. (C)), and completely dissolved after 5 minutes. Also,. Even after rusting, it started to disappear 10 minutes after the temperpet treatment ((e) in the same figure), and 15 minutes later, it completely disappeared after rusting. Moreover, in the treatment of the stampet, white turbidity of the surface did not occur unlike in the case of the treatment of the stampet from the beginning. This is because the passivation film is formed on the surface of the stainless steel in the first nitric acid treatment, and the passivation film prevents the temperet liquid from violating the surface of the stainless pipe polished to high quality. The reason is that only rust and the rest can be erased.

The stumpet may be other acid as long as it is an acid capable of dissolving iron powder, and the weak acid solution that does not violate the stainless steel is not limited to nitric acid and may be another acid solution that produces the same effect. . Further, the method of chemically removing the residual iron powder and rust of the present invention is not limited to the magnetic field beam processing,
It is also applied to other magnetic polishing methods that produce residual iron powder and rust. Further, the stainless steel pipe from which the residual iron powder and the rust are removed is not limited to the flexible pipe, and may be applied to a normal pipe or other work having a complicated shape (for example, a comb-shaped work).

[0023]

As is apparent from the above description, according to the present invention, in the inner surface polishing of the stainless steel pipe for a semiconductor device by a magnetic field beam, particularly in the inner surface polishing of a flexible pipe, residual iron powder and rust after the polishing are generated. It was possible to provide a method of completely chemically removing the pipe surface without roughening it.

[Brief description of drawings]

FIG. 1 is an overall view of a surface polishing apparatus for an inner surface of a flexible pipe to which a post-treatment of the present invention is applied.

FIG. 2 is an enlarged view of a magnetic pole unit 16 portion in FIG.

FIG. 3 is an explanatory diagram of surface polishing of FIG.

FIG. 4 is an explanatory view of the surface polishing of FIG.

FIG. 5 is an explanatory view of the surface polishing of FIG.

FIG. 6 is a structural diagram of an acid treatment device for removing foreign substances such as iron powder and rust used in the present invention.

FIG. 7 is a top view seen from above in FIG.

FIG. 8 is another structural diagram of the acid treatment device for removing foreign substances such as iron powder and rust used in the present invention.

FIG. 9 is a diagram showing a state of chemical treatment after residual iron powder and rust.

[Explanation of symbols]

1 member (flexible pipe) 5 robots 9 Guide pipe 11 Slurry abrasive grains 16 magnetic pole unit 19 Positioning member 20 Magnet drive motor 23 magnets 27 magnetic particles 31 flexible pipe 32 Acid solution 33 Support rod 34 heater 35 motor 37 Ultrasonic transducer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Juichi Hayakawa             Mutual prosperity 1-9-8 Kawagishigami, Okaya City, Nagano Prefecture             Electric Works Co., Ltd. (72) Inventor Yasuhiko Masuda             Mutual prosperity 1-9-8 Kawagishigami, Okaya City, Nagano Prefecture             Electric Works Co., Ltd. F-term (reference) 3B116 AA12 BB01 BC08                 3B201 AA12 BB01 BB96 BC08                 3C043 AC03 AC09 CC07                 3C058 AA01 AC01 CA03 CB01 DA11                       DA12

Claims (3)

[Claims] 1. A method of polishing a stainless steel pipe by magnetic field beam processing to chemically remove residual iron powder and rust after the polishing, wherein a passivation film is first washed with a weak acid solution that does not violate stainless steel. The method for removing residual iron powder and rust after polishing, which comprises cleaning the surface with a strong acid solution that dissolves all iron powder and rust. 2. The method for removing residual iron powder and rust after polishing according to claim 1, wherein the polishing of the stainless pipe by magnetic field beam processing is polishing of the inner surface of a flexible pipe. 3. The weak acid solution that does not violate the stainless steel used for the first cleaning is nitric acid, and the strong acid solution that dissolves all iron powder and rust to be used thereafter is the template solution. Item 1. A method for removing residual iron powder and rust after polishing according to Item 1 or 2.