JP3091050B2 - Support for disk-shaped substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support for a disk-shaped substrate used as a jig for plating a substrate for a magnetic disk, and more particularly to a structure of a groove wall defining an annular groove for holding a substrate. It is.

[0002]

2. Description of the Related Art In recent years, as a magnetic disk used in a magnetic disk device for high-density recording / reproducing, a thin film magnetic disk formed by a thin film technique has become mainstream. In this thin-film magnetic disk, a Ni-P alloy layer is formed as an underlayer on the surface of a disk-shaped aluminum alloy substrate by an electroless plating method, and then a nonmagnetic metal underlayer and a thin-film magnetic layer are sequentially formed thereon by sputtering. And a protective lubricating film is further formed thereon.

In the manufacture of such a magnetic disk, it is required to form a Ni-P alloy layer having a small number of defects and a uniform thickness and film quality as a lowermost underlayer.

Conventionally, generally, in an electroless plating process for forming a Ni-P alloy layer, Japanese Unexamined Patent Publication No. 63-100614 is used.
The jig for plating a substrate for a magnetic disk disclosed in Japanese Unexamined Patent Publication (Kokai) No. H10-209,086 is used. As shown in FIGS. 9 and 10, the magnetic disk substrate plating jig 1 is attached to a round bar-shaped support shaft 2 made of polypropylene, Teflon (trade name), or PPS (polyphenylene sulfide) and one end thereof. The support shaft 2 has a plurality of groove walls 4 on the peripheral surface thereof, and has an annular groove 5 defined between the groove walls 4 (for example, when the groove width c is 0). 0.5 to 1.5 mm, groove depth 1.5 to 3 mm
Degree) are formed in a plurality of rings. In the electroless plating step of forming the Ni-P alloy layer, the inner peripheral edge of the disk-shaped aluminum alloy substrate 6 on the disk hole (substrate hole) 7 side is inserted into each annular groove 5 and set one by one. The plating jig 1 is horizontally mounted on a mounting table (carousel rotary table) attached to the pretreatment and plating tank by the mounting section 3, and the rotary table is driven to rotate to rotate the plating jig 1 automatically or automatically. By revolving, the plurality of substrates 6 set
Is uniformly rotated on both surfaces of the substrate 6 while rotating or revolving.
Forming a P alloy layer;

[0005]

However, the magnetic disk substrate plating jig 1 having the above-mentioned conventional structure has the following problems. That is, during the pre-plating process and the plating process, the substrate 6 also rotates or revolves following the rotation or rotation of the plating jig 1.
And one side surface of the annular groove 5 (the side surface of the groove wall portion 5) is always in sliding contact with each other, so that the liquid flowing into the contact portion (the inner peripheral edge of the disk hole 7) in the pretreatment and the plating treatment Insufficiency and insufficient liquid discharge occur, leading to non-uniform film thickness, gas pit defects and nodule defects. Further, if the groove side surface of the annular groove 5 is rough, there is a problem that a contact portion on the substrate side is scratched due to abnormal deposition, thereby causing a surface defect.

In view of the above problems, the present invention minimizes the contact portion between the substrate and the groove side surface to minimize the inflow and discharge of a processing fluid such as a plating solution into the inner peripheral edge of the disk hole. A disk that enhances its properties, suppresses gas pit defects, nodule defects, etc., achieves uniform film thickness and film quality, and suppresses surface defects due to scratches by optimizing the surface roughness of the groove side surfaces. It is an object of the present invention to realize a support for a glass substrate.

[0007]

Means for Solving the Problems To solve the above-mentioned problems, a means adopted by the present invention is a disk-shaped substrate support which can also be used as a magnetic disk substrate plating jig. The wall portion has a groove connection gap communicating with the annular grooves on both sides at a plurality of positions in the circumferential direction. In such a case, in other words, it corresponds to the groove wall portion being a ring-shaped projection array having a plurality of projections arranged in the circumferential direction. The shape of the projection itself, the number of projections, and the like can be various.In addition, it is possible to form the projection by cutting from the support shaft, or to press-fit the projection of the molded product into the hole of the support shaft. is there. As a specific projection shape, for example, a trapezoidal projection formed by chamfering the annular groove side may be used, or a columnar projection having a semispherical head or a semielliptical spherical head may be used. Elliptic column projections may be used. Further, the projection may be substantially spherical.

By arranging a plurality of annular arrays of protrusions at a predetermined pitch in a uniform pattern in the axial direction of the support shaft, it is possible to obtain annular grooves in which a disk substrate can be set between adjacent annular arrays of projections. A support tool having such a projection pattern may be used. That is, in this projection pattern, the annular grooves of a plurality of rings are composed of an annular groove of a first group and an annular groove of a second group, and the annular grooves belonging to the first group are a pair of adjacent and identical first annular protrusions. The annular grooves belonging to the second group and being defined between the rows are defined between a pair of adjacent and identical second annular rows of projections, and the pair of first annular annular rows of projections. A pair of second annular protrusions are alternately formed in the axial direction on the support shaft, and the adjacent first annular protrusions and the second annular protrusions are equally spaced in the circumferential direction. It is characterized by being formed shifted.

Further, the surface roughness of the side surface of the annular groove is Ra0.
It is desirable that the thickness be 5 μm or less.

[0010]

In the above construction, the adjacent annular grooves communicate with each other through the groove connecting gap, and the groove walls are formed by the annular annular projections, so that the inner peripheral edge of the substrate held by the annular grooves is formed. The portion of the portion facing the groove connection gap is directly exposed to the processing fluid (plating solution in the case of plating solution processing). As a result, the inflow property and the discharge property of the processing fluid to the inner peripheral edge are significantly improved as compared with the case of the conventional support. This means that the supply of the processing fluid controlled to the predetermined concentration to the inner peripheral edge of the substrate is smoothed. Since the substrate is set between adjacent annular rows of protrusions, the contact area is also reduced as compared with the case of the conventional support. Therefore, the uniformity of film formation or processing can be achieved by the synergistic effect of the reduction in the contact area of the inner peripheral edge and the increase in the supply amount of the processing substance. The thickness and quality of the film can be made uniform, and gas pits and nodule defects can be suppressed. Also, since the contact area is small, the liquid drainage property is also good. In the case of a projection or the like having a hemispherical head, the projection and the substrate come into contact with each other by line contact or point contact. In particular, when the projection is formed substantially in a spherical shape, point contact can be achieved. In such a case, since the contact area becomes infinitely small, it is presumed that the processing fluid enters between the contact portions, and the entered fluid forms a contact buffer layer. The effect becomes more remarkable as the size of the projection is reduced.

In the present invention, when the side surface of the annular groove is set to have a surface roughness Ra of 0.5 μm or less by buffing or molding, abnormal precipitation and the like can be suppressed, so that the incidence of surface defects due to scratches can be reduced.

As described above, the area of contact with the substrate can be reduced by minimizing the size of the projections constituting the annular array of projections. However, when the size of the projections themselves is reduced, the pitch of the annular grooves is also reduced. In some cases, adjacent disk substrates come into contact during processing. Therefore, in the present invention, the plurality of annular grooves are divided into a first group of annular grooves and a second group of annular grooves, and the annular grooves belonging to the first group are adjacent and equal to each other. An annular groove defined between the annular rows and an annular groove belonging to the second group defined between a pair of adjacent and identical second annular rows of projections; And a pair of second projection annular rows are alternately and repeatedly formed in the axial direction on the support shaft, and the adjacent first projection annular row and second projection annular row projection groups are mutually equal in the circumferential direction. It is characterized by a projection pattern formed so as to be displaced from the other. According to such a projection pattern,
An adjacent pair of first annular protrusions defines a first group of annular grooves, and a pair of adjacent second annular protrusions defines a second group of annular grooves. Since the annular grooves are not located on both sides of the projection but are located only on one side, the annular grooves can have a predetermined pitch, and the contact between adjacent disk substrates can be prevented. In other words, since the protrusion pattern allows the change of the groove width of the annular groove to be relatively freely set while securing the annular groove at a predetermined pitch, it is possible to easily cope with substrates having different thicknesses in design. . The fact that the pitch of the annular groove can be ensured at a predetermined pitch can be achieved by a conventional board rack case used in an operation of setting a plurality of substrates on a support at a time and an operation of removing a plurality of substrates from the support at a time. The pitch can be matched with the pitch, and it is not necessary to prepare a board rack case with a new pitch.

[0013]

Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

Embodiment 1 FIG. 1 is a side view showing a magnetic disk substrate plating jig according to Embodiment 1 of the present invention.
The magnetic disk substrate plating jig 10 of this embodiment includes a support shaft 2 cut with a peak material (PEEK: polyetheretherketone) and a mounting portion 3 at one end thereof. It has a plurality of annular grooves 12. The groove wall of the annular groove 12 is constituted by an annular row of projections in which eight projections (warp-shaped projections) 14 are arranged in the circumferential direction. The adjacent annular grooves 12, 12 are communicated with each other by a groove connecting space 16 that defines the protrusion 14. The pitch of the annular groove 12 in this example is 6.35 mm in order to match the pitch of the board rack case, and the groove width c of the annular groove 12 is 1.40 mm in order to hold a board having a thickness of 1.25 mm. . The protrusion 14 has a substantially trapezoidal shape, and has an axial length of 4.9 mm and a circumferential length of 3.0 m.
m, height about 3.5 mm, as shown in detail in FIG.
The annular groove 12 side is formed as a chamfered surface 14a, and each corner thereof is subjected to a curved surface processing of R = 1.0 mm. The side surface of the annular groove 12 is formed to have a surface roughness Ra of 0.5 μm or less by buffing.

FIG. 2 is a side view showing a state where the substrate 6 is set in the annular groove 12 of the magnetic disk substrate plating jig. FIG. 3 is a cross-sectional view showing the state taken along line II-II in FIG. It is.

The disk substrate 6 is loosely fitted into the annular groove 12 between the annular annular projections through the disk hole (substrate hole) 7 from the front end side A of the support shaft 2, and due to the weight of the substrate, the inner peripheral edge of the disk hole 7. The upper part of the part is in contact with a part of the annular ring of projections.
When the support shaft 2 rotates around the axis, the substrate 6 attached thereto also rotates. The jig 10 in which a plurality of (for example, 20 to 30) substrates 6 are set as described above is mounted on a pretreatment tank for plating and a mounting table (carousel rotating plate) installed in the plating tank.
At the mounting part 3. Multiple jigs 1 on the mounting table
0 is mounted horizontally in a ring shape. Then, by rotating the mounting table, each jig 10 revolves around the center of the ring as the center of rotation while rotating, and a plating film is formed on the substrate 6.

In this plating step, the ratio of the inner peripheral edge of the disk hole 7 sliding in contact with the groove side wall is reduced due to the presence of the groove connection gap 16. That is, the upper part of the inner peripheral edge of the disk hole 7 is in contact with the groove side wall surface of only the three projections 14, and is reduced to a fraction of the area of the conventional contact. For this reason, the liquid inflow property and the liquid discharge property with respect to the inner peripheral edge are improved, and the liquid drainage property is also improved. Therefore, the plating film thickness and film quality can be made uniform up to the inner peripheral end of the disk hole 7, and gas pits and nodule defects can be suppressed. This is the liquid contact of the inner peripheral edge (liquid exposure)
As the ratio increases, the reduction in the contact area between the substrate 6 and the side wall of the annular groove 12 also contributes synergistically. Then, as the contact area is reduced, it is presumed that the liquid enters between the contact sites, and the entered liquid forms a contact buffer layer. In this example, since the substrate is held by the three projections, the substrate 6 does not undergo bending vibration or the like.

[Embodiment 2] FIG. 4 is a sectional view showing a mode of use of Embodiment 2 of the present invention. In the present embodiment, the protrusion 18 is also the first embodiment.
Has a trapezoidal shape, and has an axial length of 5.0.
mm, circumferential length 3.5mm, height 3.0mm,
The annular groove side is formed as a chamfered surface 18a, and each corner is subjected to a curved surface processing of R = 0.5 mm. Then, such projections 18 are equally divided into four on the circumferential surface of the support shaft.
They are arranged individually to form an annular row of projections. The annular ring array of the projections according to the first embodiment includes eight projections, but this example includes four projections. Accordingly, the substrate 6 is supported by one or two projections 18 and the contact area is reduced as compared with the first embodiment, so that the liquid inflow and liquid discharge properties are further improved. As a result, it is possible to further suppress the unevenness of the plating film thickness and the occurrence of gas pits and the like. However, since the substrate support portion may be substantially one place, the support stability is slightly low.

Third Embodiment FIG. 5 is a side view showing a main part of a third embodiment of the present invention, and FIG. 6 is a cross-sectional view taken along line III-III in FIG. In this embodiment, the annular ring of projections provided on the peripheral surface of the support shaft 2 of the plating jig includes eight cylindrical projections (round pin-like projections) 22 having a hemispherical head along the circumferential surface. Minutes. The diameter of the cylindrical projection 22 is 4.
The height is 9 mm and the height is 3.5 mm. The cylindrical projection 22 is a molded product of a peak material, and has a side surface roughness of Ra0.5.
μm or less. A plurality of insertion holes (not shown) are formed in the support shaft 2 machined by the peak material, and these are assembled by press-fitting the legs (not shown) of the cylindrical projections 22 into these holes. When the annular columnar projections 22 are formed by such columnar projections 22, the contact portions between the substrate 6 and the projections 22 are substantially in line contact, so that the total contact area is significantly reduced. For this reason, substantially all of the inner peripheral edge of the disk hole 7 is in a liquid immersion state, so that the plating film thickness is more uniform and the generation of gas pits and nodules is suppressed more than in the first embodiment and the case. Can be planned. In addition, the annular ring of projections is formed by the eight projections 22, and the upper part of the inner peripheral edge of the disk hole 7 is always supported by three projections. Higher than. Note that the head shape of the projection 22 is not limited to a hemispherical shape, and may be a semi-elliptical spherical shape. Further, the projection may be formed by a spherical head and an insertion post having a diameter smaller than the diameter thereof, and the spherical head may contact and support the substrate. In such a case, since the projection is substantially spherical, it can be supported substantially by point contact, and the total contact area can be further reduced. Also, the contact area can be reduced by reducing the size of the projection.

Embodiment 4 FIG. 7 is a side view showing Embodiment 4 of the present invention. In this embodiment, the annular grooves on the peripheral surface of the support shaft 2 include a first group of annular grooves a and a second group of annular grooves b. The annular groove a belonging to the first group is a pair of adjacent first and second annular annular projections a.
It is defined between the _{1, a 2.} The annular grooves b belonging to the second group are defined between a pair of adjacent and equal second annular annular rows b ₁ and b ₂ . The first annular annular rows a ₁ , a ₂ and the second annular annular rows b ₁ , b _2.
Is composed of nine cylindrical projections 32 each having a hemispherical head. A pair of first annular projection rows a ₁ and a ₂ and a pair of second annular annular projection rows b ₁ and b ₂ are alternately formed in the axial direction on the support shaft 2 and are adjacent to each other. The projection groups of the first annular projection row a ₁ (a ₂ ) and the second annular projection row b ₂ (b ₁ ) are formed so as to be shifted evenly in the circumferential direction. In this example, the diameter of the projection 32 is 3.5 mm, and the height is 3.5 mm. This cylindrical projection 3
2 is a molded product of a peak material, and the surface roughness of the side surface is Ra.
It is 0.5 μm or less. A plurality of insertion holes (not shown) are formed in the support shaft 2 machined by the peak material, and are combined by press-fitting the legs (not shown) of the cylindrical projections 32 into these. Therefore, the protrusion 3 of the present example
2, the annular groove a or b is located only on one side. The reason for forming such a projection pattern is that the diameter of the projection 32 is made smaller than that of the third embodiment, so that the annular grooves a,
b to a predetermined value (for example, 6.35 m).
m). If the size of the protrusion is reduced and an annular groove for supporting the substrate is provided on both sides of the protrusion, the distance between adjacent substrates is reduced, and mutual contact is caused. Therefore, by always inserting two projection annular rows between the annular grooves a and b, the substrate pitch is ensured while reducing the contact area. Here, the first annular projection row and the second annular projection row are arranged so as to be shifted from each other by 20 ° in the circumferential direction, and the projections of the first annular annular row and the second annular row of projections are not aligned. If the columns do not interfere with each other, the groove width of the annular groove can be set relatively freely while keeping the groove pitch constant even for various projection sizes in the design of the jig.

Next, in order to confirm the effect of each of the above embodiments, the surface roughness of the side surface of the annular groove is changed by buffing or forming (Example 1 is buffing, and No. 4 is a molding process), and the surface roughness and occurrence of film surface defects due to scratches were tested. Table 1 shows the results.

[0022]

[Table 1]

As is clear from this table, the surface roughness is expressed as R
By setting a to 0.5 μm or less, there is no surface defect of the film due to a contact flaw with the side surface. In the cutting process of the jig of the first embodiment, a surface roughness Ra of 1.0 μm is a limit. It is necessary to perform buff polishing to make the surface roughness less than that. Therefore, if the side surface of the annular groove is a buff polished surface, the incidence of surface defects can be suppressed as compared with the conventional case.

Next, the characteristics and surface defects when the material of the plating jig in each of the above embodiments and the conventional example were changed were tested. Table 2 shows the results.

[0025]

[Table 2]

In this table, “PEEK” means peak material (polyetheretherketone), “PP” means polypropylene, “PPS” means polyphenylene sulfide,
“PTFT” refers to polytetrafluoroethylene, “HT-
"PVC" is heat-resistant vinyl chloride. "Chemical resistance" refers to corrosion resistance to strong acids (nitric acid, sulfuric acid) and strong alkalis. As is apparent from Table 2, when the jig having the annular rows of the projections of this embodiment is employed, only the PP and HT-PVC materials are slightly inferior in chemical resistance. There were no nodule defects and no pit defects.

Next, jigs having various projection shapes and surface defects of the conventional example were tested.

Table 3 shows the results.

[0029]

[Table 3]

In this table, the "cylindrical pin shape" is the shape of the cylindrical projection of the third embodiment, as shown in FIG.
The “elliptical column shape” has a column having an elliptical cross section and has a shape shown in FIG. The “trapezoid” is the projection shape shown in the first embodiment, and is the shape shown in FIG. The “chamfered trapezoid” has a shape shown in FIG. 8D in which the “trapezoid” shown in FIG. 8C is further chamfered. As is clear from this table, although the pit defect and the nodule defect were slightly generated only in the jig having the chamfered trapezoidal protrusion, the generation of the surface defect was effectively suppressed in all of the protrusion shapes of this example.

The magnetic disk substrate plating jig shown in the above embodiment is used for forming a nickel-alloy layer by electroless plating as a base layer on the surface of a magnetic disk substrate.
The jig is used to hold a substrate for performing a plating process and a pretreatment thereof, but such a jig is used not only in the case of the plating process but also as a substrate film forming support in a film forming process such as a CVD or sputtering method. It can be used as a substrate immersion support in the etching process.

[0032]

As described above, the present invention is characterized in that adjacent annular grooves are communicated with each other by a groove connecting space, and the groove wall portion is substantially constituted by an annular array of projections. Has the following effects.

The portion of the inner peripheral edge of the substrate held in the annular groove, which faces the groove connection gap, is directly exposed to a processing substance such as a plating solution. In addition, the dischargeability is significantly improved as compared with the conventional support. Also, the contact area is reduced as compared with the conventional support. Therefore, by the interaction between the decrease in the contact area of the inner peripheral edge and the increase in the supply amount of the processing fluid, the film thickness and film quality of the inner peripheral edge can be made uniform, and gas pits and nodule defects can be suppressed. .

In the case of a projection or the like having a hemispherical head, the substrate and the projection come into contact with each other by line contact or point contact. In such a case, since the contact area becomes infinitely small, it is presumed that the processing fluid also enters between the contact portions, and the entering liquid forms a contact buffer layer. The effect becomes more remarkable as the size of the projection is reduced.

In the present invention, when the surface roughness of the side surface of the annular groove is set to Ra 0.5 μm or less, abnormal deposition and the like can be suppressed, and the incidence of surface defects due to scratches can be reduced.

Furthermore, a pair of first annular projection rows and a pair of second annular annular rows are alternately and repeatedly formed in the axial direction on the support shaft, and the adjacent first annular annular rows and second annular projection rows are formed. When the projection group of the annular projection row is formed as a projection pattern formed so as to be shifted evenly in the circumferential direction, the annular grooves are not located on both sides of the projection constituting the annular projection row, but only on one side. Since the annular groove is located, the annular groove can be formed at a predetermined pitch, and contact between adjacent disk substrates can be prevented. In other words, since the protrusion pattern allows the change of the groove width of the annular groove to be relatively freely set while securing the annular groove at a predetermined pitch, it is possible to easily cope with substrates having different thicknesses in design. .

[Brief description of the drawings]

FIG. 1 is a side view showing a magnetic disk substrate plating jig according to a first embodiment of the present invention.

FIG. 2 is a side view showing a state where a substrate is set in an annular groove of the magnetic disk substrate plating jig.

FIG. 3 is a cross-sectional view showing a state viewed along line II-II in FIG. 2;

FIG. 4 is a cross-sectional view showing a usage state of a magnetic disk substrate plating jig according to a second embodiment of the present invention.

FIG. 5 is a side view showing a main part of a jig for plating a magnetic disk substrate according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a state viewed along line III-III in FIG. 5;

FIG. 7 is a side view showing a magnetic disk substrate plating jig according to Embodiment 4 of the present invention.

FIG. 8 is a perspective view showing the shape of each protrusion in the embodiment of the present invention.

FIG. 9 is a side view showing a conventional magnetic disk substrate plating jig.

FIG. 10 is a cross-sectional view showing a state viewed along line AA in FIG. 10;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 2 ... Support shaft 3 ... Mounting part 6 ... Substrate 7 ... Disk hole (substrate hole) 10 ... Magnetic disk substrate plating jig 12 ... Circular groove 14 ... Protrusion (warp-shaped projection) 14a ... Chamfered surface 16 ... Groove connection gap 18 ... projections 22, 32 ... cylindrical projections a _1, a ₂ ... a first protrusion annular array b _1, b ₂ ... second protrusion annular rows a ... front-end surface side

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukihisa Ishii 1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. No. 1 Inside Fuji Electric Co., Ltd. (72) Inventor Toshio Takei 133-4 Shimosuwa-cho, Suwa-gun, Nagano Prefecture Inside Nakahara Chemical Co., Ltd. (72) Inventor Noboru Sugiyama 133-4 Shimosuwa-cho, Suwa-gun, Nagano Prefecture Nakahara (58) Investigated field (Int.Cl. ⁷ , DB name) C23C 18/00-18/54 C23C 14/50 C23C 16/44 C23F 1/08 102 G11B 5/84

Claims (11)

(57) [Claims] A disk-shaped substrate support provided with a support shaft having a plurality of annular grooves on a peripheral surface thereof, wherein a groove wall defining the annular groove has a plurality of circumferential grooves. A support for a disk-shaped substrate, characterized in that the support has a groove connection gap communicating with the annular grooves on both sides. 2. A disk-like substrate support having a support shaft having a plurality of annular grooves on a peripheral surface thereof, wherein a groove wall defining the annular groove has a plurality of circumferentially extending grooves. A support for a disk-shaped substrate, wherein the support is an annular row of projections in which projections are arranged. 3. The support for a disk-shaped substrate according to claim 2, wherein said projection is a trapezoidal projection formed by chamfering said annular groove. 4. The disk-shaped substrate support according to claim 3, wherein a side surface of the trapezoidal projection is a buffed surface. 5. The disk-shaped substrate support according to claim 2, wherein the annular grooves of a plurality of rings include a first group of annular grooves and a second group of annular grooves. The annular grooves belonging to the second group are defined between a pair of adjacent and equal second annular arrays of protrusions, and the annular grooves belonging to the second group are defined between a pair of adjacent annular arrays of first protrusions. A pair of first projection annular rows and a pair of second projection annular rows are formed alternately and repeatedly in the axial direction on the support shaft, and the adjacent first projection annular rows and second A projection for a disk-shaped substrate, wherein the projections in the annular projection row are formed so as to be shifted evenly in the circumferential direction. 6. The support for a disk-shaped substrate according to claim 2, wherein the projection is a cylindrical projection having a hemispherical head. 7. The support for a disk-shaped substrate according to claim 2, wherein said projection is an elliptic columnar projection having a semi-elliptical spherical head. Utensils. 8. The support for a disk-shaped substrate according to claim 2, wherein the projection is substantially a sphere. 9. The disk-shaped substrate support according to claim 6, wherein the projection is a molded product. 10. The disk-shaped substrate support according to claim 1, wherein a side surface of said annular groove has a roughness of Ra 0.5 μm or less. Support for substrate. 11. The disk-shaped substrate support according to any one of claims 1 to 10, wherein the support for the disk-shaped substrate is formed on a surface of the magnetic disk substrate by nickel plating by an electroless plating method.
A disk-shaped substrate support jig, which is a magnetic disk substrate plating jig for holding said substrate for performing a plating process and a pretreatment when forming a phosphorus alloy layer.