JP2001164383A - Method for forming groove for generating dynamic pressure and resist solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a groove for generating dynamic pressure capable of forming a groove for generating dynamic pressure with high working precision and to provide an etching solution. SOLUTION: In this method for forming a groove for generating dynamic pressure, the whole face of the surface of a raw member 10 is deposited with a resist solution obtained by incorporating a corrosion resistant resist solution with a sublimation pigment to form a resist layer (b), the part in which a groove for generating dynamic pressure is formed is irradiated with laser light L with a prescribed wavelength to remove the resist layer on the part in which a groove for generating dynamic pressure is formed is removed (c), the raw member 10 is immersed into an etching solution E, and the raw member 10 exposed from the resist layer 11 is etched to form a groove 12 for generating dynamic pressure (d), and the resist layer 11 remaining on the surface of the raw member 10 is removed (e).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic pressure generating groove forming method for forming a dynamic pressure generating groove in a dynamic pressure bearing.
More particularly, the present invention relates to a method for forming a dynamic pressure generating groove capable of forming a dynamic pressure generating groove with high processing accuracy, and a resist solution.

[0002]

2. Description of the Related Art Conventionally, dynamic pressure bearings have been used as bearings for motors in various disk devices such as hard disk drives, rotary polygon mirror devices such as printers, and other rotating devices. The dynamic pressure bearing includes a bearing member fixed to the rotating body side and a bearing member fixed to the non-rotating body side, and a dynamic pressure generating means is formed on one of opposing surfaces of these bearing members. It was done. The dynamic pressure generating means includes a groove for generating dynamic pressure. At the time of rotation of the rotating body, a fluid such as air or oil is caught between the two bearing members by a dynamic pressure generating means such as a dynamic pressure generating groove, and a dynamic pressure is generated. Supported against the body. Such a dynamic pressure bearing has an advantage that friction between members at the time of high-speed rotation is small and good durability can be obtained.

[0003] As a method of forming a groove for generating dynamic pressure in the case of manufacturing the above-mentioned dynamic pressure bearing, there is a technique of etching an original member (etching), and the following technique is employed. . That is, an original member for forming the dynamic pressure generating groove is formed in advance of a metal such as stainless steel or aluminum, and a corrosion-resistant layer is formed on the surface of the original member by a resist solution. Then, only a portion corresponding to the groove for generating dynamic pressure is vaporized and removed by laser light irradiation to form a mask pattern. Thereafter, the original member is immersed in a chemical solution, and only the exposed portion is corroded to form a dynamic pressure generating groove. The corrosion-resistant layer is removed with a solvent after the grooves for generating dynamic pressure are formed.

[0004]

However, in the method of forming a groove for generating dynamic pressure as in the above-described technique, the laser beam must be irradiated at an intensity that does not damage the original member. Therefore, the corrosion-resistant film may not completely evaporate in the portion irradiated with the laser beam, and the carbide may remain as a burnt residue. As a result, etching may not be performed uniformly by the etchant due to the residue, and the dynamic pressure generating groove may not be accurately formed. When the groove for generating dynamic pressure is used for a bearing of a polygon mirror motor or the like of a printer, it has a depth of 5 to 7, 8 μm from the surface of the original member, and requires precise processing. And avoid the above-mentioned residue,
It is an important subject to form a dynamic pressure generating groove with high processing accuracy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide a dynamic pressure generating groove forming method capable of forming a dynamic pressure generating groove with high processing accuracy, and a resist solution. Aim.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a resist for forming a resist layer which is resistant to an etchant on a surface of an original member on which a groove for generating dynamic pressure is formed. A layer forming step, after the resist layer forming step, irradiating a laser beam to the portion where the dynamic pressure generating groove is to be formed, removing the resist layer at the portion where the dynamic pressure generating groove is to be formed, and removing the surface of the original member. A pattern forming step of exposing the substrate, and after the pattern forming step, immersing the original member where the position for forming the dynamic pressure generating groove is exposed in an etchant, etching the exposed portion of the original member. An etching step of forming a groove for generating dynamic pressure, and after the etching step, including a resist layer removing step of removing the resist layer remaining on the cylindrical member, wherein the resist layer contains a sublimation dye. Become Providing a dynamic pressure generating groove forming method comprising and.

In this method for forming a groove for generating dynamic pressure, a sublimation dye is contained in the resist layer, so that it is easily vaporized by laser light irradiation, and no burning remains. Also,
Since it is easily vaporized by laser light irradiation, a large amount of heat is not required, and the cost for laser irradiation can be reduced. Further, since the gas is easily vaporized by the irradiation of the laser beam, the range of choice of the laser beam is widened, and a carbon dioxide gas laser which has not been used conventionally can be adopted. The above-described sublimation dye preferably has a coloration close to a complementary color to the color of the laser beam. This is because laser light is easily absorbed, and the resist layer can be removed with high efficiency to form a mask pattern.

In the method of forming a groove for generating dynamic pressure according to the present invention,
The resist layer forming step includes: an attaching step of attaching a resist solution containing a sublimation dye to the exposed surface of the original member; and, after the attaching step, the resist property attached to the surface of the original member. And forming a resist layer by making the solution corrosion-resistant.

Further, the present invention achieves the above object by providing a resist solution for etching comprising a sublimable dye contained in a resist solution which can be made corrosion-resistant. As the resist solution that can be made corrosion-resistant, a resist solution used when forming a dynamic pressure generating groove by etching can be used without any particular limitation.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory view showing each step of one embodiment of a method for forming a groove for generating dynamic pressure of the present invention. The groove forming method for generating dynamic pressure of the present embodiment,
This is adopted in a step of forming a dynamic pressure generating groove in a shaft when a shaft of a dynamic pressure bearing is manufactured. The shaft formed with the dynamic pressure generating groove according to the present embodiment is coaxially arranged in the hollow portion of the support member having the columnar hollow portion, and the dynamic pressure in the radial direction is formed between the shaft and the inner peripheral wall of the support member. generate.

As shown in FIG. 1, in the dynamic pressure generating groove forming method of the present embodiment, first, a columnar original member 10 for forming a dynamic pressure generating groove is prepared (original member forming step) (see FIG. 1). 1
(A). The original member is made of a metal such as aluminum or stainless steel, and has the same shape (in the present embodiment, a columnar shape) and size as the shaft of the dynamic pressure bearing except that the dynamic pressure generating groove is not formed. It is a thing.

Then, on the surface of the original member 10, a resist layer which is corrosion-resistant to an etching solution and contains a sublimation dye is formed. In this embodiment, the resist layer forming step includes an attaching step of attaching a resist solution containing a sublimation dye (resist solution) to the surface of the original member 10, and a resist solution attaching to the surface of the original member 10. And forming a resist layer by making the resist corrosion-resistant.

That is, first, a resist solution containing a sublimation dye is applied to the entire exposed surface of the original member 10. The resist solution to be attached is formed by adding a sublimation dye to a resist solution conventionally used for forming a resist layer, and mixing and dissolving the sublimation dye in the conventionally used resist solution. Or by dissolving a sublimation dye together with a solute of the resist solution in a solvent at the time of preparing the resist solution.

As the sublimation dye, a dye that easily absorbs with respect to the wavelength of the laser beam used for removing the resist layer in the pattern formation step described below is preferable. This is because laser light is easily absorbed, and the resist layer can be removed with high efficiency to form a mask pattern. The color of the sublimation dye that most efficiently absorbs the laser wavelength (red) is the complementary color blue. Resist solution 11
Are applied to the surface of the original member 10 by spraying, a method in which a pressurized body impregnated with a resist solution is pressed against the original member 10 to slide or rotate, or a method in which the original member is immersed in the resist solution. A method of removing the excess solution by centrifugal removal by rotating the original member at a predetermined number of revolutions after dipping the 10 is immersed.

Then, the resist solution adhered to the surface of the original member 10 is made corrosion-resistant to form a resist layer 11 (corrosion-resistant step) (FIG. 1B). As a method for achieving corrosion resistance, a method which has been conventionally employed according to the resist solution attached to the original member 10 is employed. For example, an exposure process of exposing with light of a predetermined wavelength, a heat treatment such as leaving the substrate at a predetermined temperature for a predetermined time, or a combination thereof.

Next, a laser beam L is emitted toward the original member 10 having the resist layer adhered to the surface thereof, and the resist layer at the portion where the dynamic pressure generating groove is to be formed is removed to expose the surface of the original member. (Pattern forming step) (FIG. 1C). As a result, a mask pattern is formed on the surface of the original member 10 by the resist layer 11 from which the dynamic pressure generating groove has been removed. As a type of the laser light L to be applied, a laser light L by an argon ion laser, a YAG laser, a carbon dioxide laser, or the like can be used. It is preferable that the laser beam L has an output that does not affect the surface of the original member 10 such as damaging it. Further, it is necessary to have wavelength energy larger than the optical absorption edge energy level of the resist layer 11. In the present embodiment, since the resist layer 11 contains a sublimation dye, the resist layer 11 is easily vaporized by the laser beam L, and the resist layer at the portion where the dynamic pressure generation groove is formed is reliably removed without remaining. .

Subsequently, the original member 10 having the mask pattern of the resist layer 11 formed on the surface is immersed in an etching solution E (etching step) (FIG. 1D). As a result, the surface of the original member 10 to which the resist layer 11 is adhered is maintained as it is, and the exposed surface of the original member 10 from which the resist layer 11 has been removed is corroded by the etching solution E. As a result, the original member 10 is etched according to the mask pattern of the resist layer 11, and the dynamic pressure generating groove 12 is formed in the original member 10. As the etchant E, an etchant conventionally used in an etching process for forming a dynamic pressure generating groove of a dynamic pressure bearing can be used. For example, when the original member 10 is made of aluminum,
Using a mixed solution of phosphoric acid, acetic acid, nitric acid and pure water as the etching solution E, the etching can be performed at 60 to 90 ° C. When the original member 10 is stainless steel, an aqueous ferric chloride solution is used. Etching at room temperature. Further, the dynamic pressure generating groove 15 to be formed depends on the size of the original member 10, the distance between the original member and the opposing member in the dynamic pressure bearing in which the original member 10 is used, the use, and the like. When used for a bearing of a polygon mirror motor or the like, the thickness is preferably 5 to 7, 8 μm from the surface of the original member 10. The type, concentration, temperature, and etching time of the etching solution E are the same as those in the related art, depending on the type of the resist layer 11 (resist solution), the type of the original member 10, the depth of the groove for generating dynamic pressure, and the like. Is selected and determined.

Then, the original member 10 is taken out of the etching solution E, and the etching solution E is washed off, and then immersed in an organic solvent such as acetone or thinner to dissolve and remove the resist layer 11 on the surface of the original member 10 (resist). Layer removal process)
(FIG. 1E), the dynamic pressure generating groove forming method of the present embodiment ends.

As described above, in the dynamic pressure generating groove forming method of the present embodiment, the resist layer 11 is formed by the resist solution containing the sublimation dye. And the resist layer 1
1 is easily vaporized because it contains a sublimation dye, and can be reliably removed without leaving the resist layer 11 in the dynamic pressure generating groove forming portion by laser light having an energy level that does not damage the original member 10. it can. And
By reliably removing the resist layer 11 at the position where the dynamic pressure generating groove is formed, the dynamic pressure generating groove can be formed with high accuracy. According to the present embodiment, since the resist layer 11 is easily vaporized and removed, a carbon dioxide gas laser can be used. According to the present embodiment, the resist layer 1
Because 1 is easily vaporized and removed, less heat is required and costs are reduced.

It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention. For example, in each of the above-described embodiments, the dynamic pressure generating groove is formed on the outer peripheral surface of the cylindrical shaft of the dynamic pressure bearing. However, the shape and position of the member forming the dynamic pressure generating groove are not limited thereto. However, it can also be formed on the outer peripheral surface or inner peripheral surface of a cylindrical sleeve, or on the end surface of a cylindrical shaft or a cylindrical ring. Grooves for generating dynamic pressure may be formed on the end face and the outer peripheral face or the inner peripheral face.

In each of the above embodiments and the modified examples, the original member 10 has the same shape and size as those used for the dynamic pressure bearing except that the grooves for generating dynamic pressure are not formed. The groove for dynamic pressure generation is formed, but it is not limited to this. A member with a longer shaft length than the shaft or sleeve used for the dynamic pressure bearing is used, and the groove for dynamic pressure generation is formed on the peripheral surface Later, both ends are cut off or ground, and a plurality of grooves for generating dynamic pressure are formed at a time in a member having a shaft length several times that of a shaft or a sleeve used for a dynamic pressure bearing, and the axial direction is thereafter formed. To form a plurality of shafts and sleeves. If both ends are cut and ground after forming the dynamic pressure generating groove, even if both ends are etched, the processing accuracy of the shaft or sleeve as a final product is not affected, so that the resist layer 11 is not formed. You can also put it.

[0022]

As described above, according to the present invention,
It is possible to form the dynamic pressure generating groove with high processing accuracy easily and at low cost without damaging the original member.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing each step of an embodiment of a dynamic pressure generating groove forming method of the present invention.

[Explanation of symbols]

 Reference Signs List 10 original member 11 resist layer 12 groove for generating dynamic pressure L laser beam E etching liquid

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naoki Kawawada 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba SII Micro Precision Co., Ltd. (72) Inventor Atsushi Ota 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba Ban SAI Micro Precision Co., Ltd. F-term (reference) 4K057 WA11 WB02 WB05 WC05 WC10 WE02 WE04 WE08 WE12 WG02 WN06

Claims (3)

[Claims] A resist layer forming step of forming a resist layer having corrosion resistance to an etchant on a surface of an original member on which a dynamic pressure generating groove is formed; and a step of forming the dynamic pressure generating step after the resist layer forming step. A pattern forming step of irradiating a laser beam to a portion where a groove for forming a groove is to be formed, removing a resist layer at a portion where a groove for generating a dynamic pressure is to be formed, and exposing a surface of the original member; An etching step of immersing the original member where the position for forming the generation groove is exposed in an etching solution and etching an exposed portion of the original member to form a dynamic pressure generation groove; and after the etching step, A resist layer removing step of removing the resist layer remaining on the cylindrical member, wherein the resist layer contains a sublimation dye. 2. The step of forming a resist layer includes: an attaching step of attaching a resist solution containing a sublimation dye to an exposed surface of the original member; and adhering to the surface of the original member after the attaching step. A corrosion-resistant step of forming the resist layer by corroding the resist solution thus formed.
3. The method for forming a groove for generating dynamic pressure according to item 1. 3. A resist solution for etching, characterized in that a resist solution that can be made corrosion-resistant contains a sublimation dye.