JPH07310182A - Magnetic disk substrate holder - Google Patents

Abstract

PURPOSE:To enhance the stability of electrical contact between a substrate holder and substrates by providing the peripheral surfaces in the bottom of plural substrate holding holes formed at a planar body with V-shape holding grooves specified in the central angle, opening angle and substrate infiltration depth. CONSTITUTION:This substrate holder 1 to be used for through-film formation is provided with the plural substrate holding holes 4 for perpendicularly holding the substrates 3 on the planar body 2 for transporting the substrates 3. The peripheral surfaces in the bottoms of the substrate holding holes 4 are provided with the V-shape holding grooves 41. The V-shape holding grooves 41 are so formed as to come into contact with the substrates 3 having the central angle <=130 deg. within the range of the arc parts of these substrates and to satisfy the conditions of the opening angle 70 to 120 deg. and the infiltration depth of 0.2 to 0.4m of the substrates 3. The magnetic disks which permit high-density recording are stably produced by using such substrate holder 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk substrate holder, and more specifically, it is used for through film formation of a magnetic disk and can stably manufacture an excellent magnetic disk capable of high density recording. The present invention relates to a magnetic disk substrate holder that can be used.

[0002]

2. Description of the Related Art Conventionally, as a metal thin film type in-plane magnetic disk, an underlayer containing Cr as a main component, a magnetic layer containing Co as a main component, and a protection component containing C as a main component are formed on a non-magnetic substrate by a sputtering method. A magnetic disk formed by sequentially forming layers is widely used. In the manufacture of such a magnetic disk, a through film forming method is widely used in which a substrate is held on a substrate holder and a film is formed on both surfaces of the substrate while passing the front surface of a target at a constant speed.

FIG. 5 is a schematic explanatory view of an example of a through film forming apparatus (sputtering apparatus). The through film forming apparatus includes a loading chamber (11) for loading a substrate into a substrate holder (1) and introducing the substrate from the atmosphere into a vacuum process, a heating chamber (12) for heating the substrate in a vacuum, and a first film deposition chamber (13). ), A buffer chamber (1) arbitrarily arranged to connect a plurality of film forming chambers
4), second film forming chamber (15), discharge chamber (16) for taking the substrate out of the vacuum process to the atmosphere, and loading chamber (11) for these
And a return system (17) connecting the discharge chamber (16) with the discharge chamber (16).

As the substrate holder (1), a plurality of substrate holding holes for vertically holding the magnetic disk substrate are provided in a plate-like body which is vertically supported and conveyed in the through film forming apparatus. A structure in which a holding groove is provided on the bottom peripheral surface of the holding hole is adopted. A substrate holder having such a structure is known and described in, for example, US Pat. No. 4,735,701. That is, in the above-mentioned publicly known document, the bottom peripheral surface of the substrate holding hole is in contact with the circular arc portion of the magnetic disk substrate having a central angle of 150 °, the opening angle is 60 °, and the depth is 1 °. A magnetic disk substrate holder having a V-shaped holding groove of 0.53 mm is disclosed. Note that FIG.
In the figure, reference numeral (18) is an underlayer target unit, reference numeral (19) is a magnetic layer target unit, reference numeral (20).
Is a target unit for protective layer.

In order to improve the recording density of the magnetic disk, it is important to increase the coercive force of the magnetic recording layer. In the film forming process of the magnetic disk having the above layer structure, the substrate at the time of forming the underlayer and the magnetic layer is used. It is important to keep the temperature of the substrate high, and normally the maximum temperature of the substrate is 200 to 350 ° C.
(See Institute of Electronics, Information and Communication Engineers; CPM 88-92).

[0006]

By the way, since the substrate holder is usually thicker than the substrate, the heat capacity per unit area is larger in the substrate holder, and as a result, there is a difference in temperature between the substrate holder and the substrate. A difference in thermal expansion occurs. Therefore, the contact state between the substrate holder and the substrate changes in the process due to the temperature difference between the substrate holder and the substrate.
When designing the holding groove of the substrate holder, it is important to consider so that the change in the contact state between the substrate holder and the substrate due to the difference in thermal expansion does not cause deformation or heat transfer to the substrate.

In order to increase the coercive force of the magnetic disk, bias film formation of the magnetic layer is effective (Japanese Patent Laid-Open No. 2-1264).
24, Japanese Patent Publication No. 4-50653). Such bias film formation can be performed by forming a conductive layer on the surface of an insulating substrate in advance. And
In the through film formation, normally, by electrically connecting the substrate holder and the substrate and controlling the potential of the substrate holder,
This is done by applying the same potential to all the substrates held by the substrate holder. Therefore, in the substrate holder to which the bias film formation is applied, it is important to design the holding groove so that the electrical contact between the substrate holder and the substrate can be enhanced and stabilized.

Further, in order to increase the recording capacity per magnetic disk, it is effective to improve the recording density and to expand the recording area, and to expand the recording area of the magnetic disk over the inner and outer circumferences. Is desired. However, in the film formation on the outer peripheral portion of the magnetic disk, a non-film formation region occurs due to the shadow effect of the holding groove of the substrate holder. The reduction of the non-film formation area can be achieved by reducing the penetration depth of the substrate in the holding groove. However, if the penetration depth is too small, the substrate may come off due to the vibration caused by the movement of the substrate holder inside the device. To do. Therefore, when designing the holding groove of the substrate holder, it is important to consider so that the non-film formation area can be reduced without the substrate falling off.

As described above, the structure of the magnetic disk substrate holder used for the through film formation of the magnetic disk is extremely important for stably manufacturing an excellent magnetic disk capable of high density recording, but it is still unclear. No satisfactory substrate holder has been proposed. The present invention has been made in view of the above circumstances, and an object thereof is to avoid adverse effects due to a difference in thermal expansion between a substrate holder and a substrate, and to improve stability of electrical contact between the two for bias film formation. An object of the present invention is to provide a magnetic disk substrate holder which is improved and which can reduce the non-film-forming area and prevent the vibration and dropping of the substrate.

[0010]

That is, the gist of the present invention is a magnetic disk substrate holder (1) used for through film forming of a magnetic disk, which is vertically supported and conveyed in a through film forming apparatus. The plate-like body (2) is provided with a plurality of substrate holding holes (4) for vertically holding the magnetic disk substrate (3), and the central angle ( a) contacts within the arc portion of the magnetic disk substrate (3) of 130 ° or less, the opening angle (b) is 70 to 120 °, and the depth of penetration of the magnetic disk substrate (3) The magnetic disk substrate holder is characterized in that (c) is provided with a V-shaped holding groove (41) of 0.2 to 0.4 mm.

The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a front explanatory view schematically showing an example of a magnetic disk substrate holder of the present invention, FIG. 2 is an enlarged front explanatory view of a substrate holding hole in the substrate holder shown in FIG. 1, and FIG. 3 is a substrate holding hole. 4 is a sectional explanatory view of a holding groove provided in FIG. 4, and FIG. 4 is a sectional explanatory view of a holding groove for comparison.

The substrate holder (1) of the present invention is used for through film formation and is made of, for example, aluminum or an alloy thereof, like the conventionally known substrate holder. The substrate holder (1) of the present invention is, like the conventionally known substrate holder, a plurality of substrates which vertically hold the substrate (3) on the plate-like body (2) which is vertically supported and conveyed in the through film forming apparatus. Substrate holding hole (4). And the plate-like body (2)
Are usually mounted on a dolly (5) and moved within the device.

A V-shaped holding groove (41) is provided on the peripheral surface of the bottom of the substrate holding hole (4). The structure or shape of the V-shaped holding groove (41) is such that the V-shaped holding groove (41) contacts within the range of the arc portion of the substrate (3) having a central angle (a) of 130 ° or less and the opening angle (b) is 70 to 120 °. It is important that the penetration depth (c) of the substrate (3) satisfies the condition of 0.2 to 0.4 mm.

That is, when the substrate (3) having the central angle (a) exceeding 130 ° is contacted within the arc portion, the thermal expansion of the substrate (3) occurs at the contact point with the V-shaped holding groove (41). The plastic deformation of the substrate (3) due to the restraint increases,
In addition, the heat conduction to the V-shaped holding groove (41) increases as the contact range with the V-shaped holding groove (41) increases. The V-shaped holding groove (41) is preferably in contact with the arcuate portion of the substrate (3) having a central angle (a) of 60 to 125 °.

In the present invention, the central angle (a) is 130 °.
Hereinafter, preferably contacting within the range of the arc portion of the substrate (3) of 60 to 125 ° means that there is a contact point within the range of such arc portion and the arc of the substrate (3) exceeds the above center angle. It means that it does not come into contact with a part. Therefore, the V-shaped holding groove (41) illustrated in FIG. 2 has an arc shape following the arc portion of the substrate (3), but it is not always necessary and the arc shape may be partially omitted. It is also possible to form an appropriate number of protrusions.

The opening angle (b) of the V-shaped holding groove (41)
Is less than 70 °, a sufficient groove width cannot be ensured in the penetration depth (c) of the substrate (3) of 0.2 to 0.4 mm, and the V-shaped holding groove (41) of the substrate (3) is not secured. ) Is difficult to attach and detach, and the opening angle (b) exceeds 120 °,
The holding stability of the substrate (3) in the V-shaped holding groove (41) is lowered, and the substrate (3) is easily dropped. V-shaped holding groove (4
The opening angle (b) of 1) is preferably 80 to 110 °.

When the penetration depth (c) of the substrate (3) into the V-shaped holding groove (41) is less than 0.2 mm, V
When the holding stability of the substrate (3) in the die holding groove (41) is lowered and the substrate (3) easily falls off, and the penetration depth (c) of the substrate (3) exceeds 0.4 mm, V The shadow effect due to the mold holding groove (41) is large, and the non-film formation area of the substrate (3) is increased. The substrate holder (1) of the present invention contacts within the range of the arc portion of the substrate (3) having a central angle (a) of 130 ° or less and an opening angle (b) of 70.
~ 120 ° and the penetration depth (c) of the substrate (3)
Since the V-shaped holding groove (41) having a thickness of 0.2 to 0.4 mm is provided, the stability of electrical contact between the substrate holder (1) and the substrate (3) is enhanced.

By using the substrate holder (1) of the present invention, an excellent magnetic disk capable of high density recording can be stably manufactured. As the substrate, a commercially available substrate called Substrate, that is, Al-
A base film-formed substrate in which a base film of electroless plating of Ni-P is provided on the surface of a Mg alloy substrate and the base film is mirror-finished (polished) is preferably used. Other,
It is also possible to use a substrate made of a material such as copper, titanium, glass, ceramics, carbon or silicon. Usually, the substrate is processed into a disk shape, the substrate itself has a thickness of about 0.3 to 3 mm, and the base film has a thickness of about 5 to 30 μm.
m. The above substrate is used after being processed into a chamfer shape.

The substrate is subjected to a texture processing and the like before use in accordance with a conventional method. The texture processing is a mechanical processing performed to give a very fine striation pattern (groove) or unevenness to the mirror surface of the base film. Further, if necessary, chemical etching or electrolytic etching (electrolytic polishing) treatment can be performed as a finishing treatment for removing burrs and burrs after the texture treatment. By these processes, the attraction between the magnetic disk and the magnetic head is prevented, the contact start stop (CSS) characteristics are improved, and the magnetic anisotropy is improved.

The underlayer may be a conventionally known nonmagnetic underlayer, and can be formed of, for example, Cr, Ti, Ni or the like. And, Cr or Ti is usually S in a range of several atomic% in a range that does not impair their crystallinity.
It may be an alloy containing i, V, Cu or the like. In the present invention, a Cr-based underlayer is particularly suitable. The thickness of the underlayer is usually 1 to 300 nm, preferably 5 to 2
00 nm.

The magnetic layer is made of Co--Cr, Co--Ni, Co.
It is preferably formed of a Co-based alloy represented by —Cr—X. Here, X is Li, Si, Ca, T
i, V, Cr, Ni, As, Y, Zr, Nb, Mo, R
u, Rh, Ag, Sb, Hf, Ta, W, Re, Os,
Ir, Pt, Au, La, Ce, Pr, Nd, Pm, S
Examples include one or more elements selected from the group consisting of m and Eu. Regarding the thickness of the magnetic layer, the product (Br · t) of the residual magnetic flux density (Br) and the thickness (t) of the magnetic layer is 50 to 700 (G · μm), preferably 75 to 500.
It is preferable to select (G · μm).

As the protective layer, a carbonaceous protective layer is suitable. In particular, an amorphous carbon protective layer or a hydrogenated carbon protective layer formed by using a carbon target in an atmosphere of a rare gas such as argon or He or an atmosphere of coexistence with a small amount of hydrogen is preferable. The thickness of the protective layer is usually 5
˜50 nm. In the present invention, if necessary,
A lubricating layer can be formed on the surface of the protective layer. As the lubricant, a fluorine-based liquid lubricant such as perfluoropolyether and solid lubricant such as fatty acid are used. The thickness of the lubricating layer is usually 0.5-10 nm.

As the sputtering method, a direct current magnetron sputtering method is usually adopted, but an alternating current magnetron sputtering method can also be adopted. Ar gas is usually used as the gas introduced into the sputtering apparatus, but other rare gases can also be used.
The degree of vacuum in the sputtering device is usually 5 × 10 ⁻⁴ to 2
X10 ^-2 , preferably 1 x 10 ^-3 to 1 x 10 ^-2 Torr
The substrate temperature is usually 150 ° C. or higher, preferably 2
The temperature is set to 00 to 300 ° C.

The bias voltage may be applied, for example, by applying a negative voltage to the substrate with respect to the ground portion of the sputtering apparatus body (substrate bias method), by using the substrate potential as the ground potential and the plasma potential as the ground potential. It is possible to adopt a method of making it higher.

The negative bias voltage applied to the substrate bias method is usually -50 V or less, preferably -50 to -5.
00V, more preferably -100 to -400V. On the other hand, the latter method described above can be carried out, for example, by disposing an intermediate electrode in the vicinity of the target material, and the positive bias voltage applied to such an intermediate electrode method is usually 50 V or more, preferably It is set to 50 to 500V, and more preferably 100 to 400V.

The intermediate electrode method described above can avoid the disadvantage of the substrate bias method, that is, the disadvantage that the bias voltage applying mechanism is complicated in the continuous manufacturing method in which the substrates are sequentially moved in the sputtering apparatus. ,
This is the preferred method.

[0027]

EXAMPLES Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Examples 1 to 3 and Comparative Examples 1 to 2 The substrate holder shown in FIG. 1 provided with the substrate holding holes shown in FIGS. 2 and 3, and shown in Table 1 on the peripheral surface of the bottom of the substrate holding hole. A substrate holder having a holding groove with the indicated dimensions was used. As the substrate, an aluminum alloy disk-shaped substrate, which had been subjected to Ni-P plating by an electroless plating method and then subjected to polishing and texturing, was used.

[0029]

[Table 1] ──────────────────────────────────── Example Comparative Example 1 2 3 1 2 Substrate Front shape of holding hole Figure 2 Figure 2 Figure 2 Figure 2 Figure 2 Center angle (a) (degrees) 80 100 120 140 172 Cross-sectional shape of holding groove Figure 3 Figure 3 Figure 3 Figure 3 Figure 3 Opening angle (b) (degrees) ) 100 100 100 100 100 Depth of penetration (c) (mm) 0.3 0.3 0.3 0.3 0.3 ───────────────────────────── ──────── The central angle (a) represents the central angle in the arc of the substrate that contacts the substrate holder.

Then, the substrate was mounted in the holding groove of the substrate holder and placed in the through film forming apparatus shown in FIG. 5 to compare the heating characteristics of each substrate in the heating chamber. That is, 35
The temperature of the heating chamber was stabilized by the heater set at 0 ° C., and the change with time of the substrate temperature immediately after the substrate holder was conveyed to the heating chamber and stopped was measured. The substrate temperature was measured by a thermocouple fixed to the substrate.

FIG. 6 is a graph showing the measurement results of the change in the substrate temperature with time in Examples 1 to 3 and Comparative Examples 1 and 2, in which, is Example 1, is Example 2, and is Example 3. , Is the result of Comparative Example 1, is the result of Comparative Example 2, and is the result for the substrate holder. In the case of the substrate holders of Examples 1 to 3, the temperature rise of the substrate is linear up to 300 ° C. On the other hand, in the case of the substrate holders of Comparative Examples 1 and 2, the slope of the temperature rise of the substrate changes at about 150 ° C. It is considered that this is because the substrate is restrained by the holding groove due to the thermal expansion of the substrate, and as a result, the heat conduction with the substrate is changed.

Examples 4 to 6 and Comparative Examples 3 to 4 The substrate holder shown in FIG. 1 provided with the substrate holding holes shown in FIGS. 2 to 4, the bottom peripheral surface of the substrate holding hole is shown in Table 2. A substrate holder having a holding groove with the indicated dimensions was used. As the substrate, in addition to the aluminum alloy disc-shaped substrate (AL substrate) similar to that of Example 1, a glass disc-shaped substrate (GL substrate) having a Cr layer on the surface by a sputtering method is used.
It was used.

Then, the substrate was mounted in the holding groove of the substrate holder and placed in the through film forming apparatus shown in FIG. First,
The temperature of the substrate was raised to 280 ° C. in the heating chamber. Next, in the first film forming chamber, Ar gas pressure of 5 × 10 ⁻³ T
Under the condition of ooor, the substrate holder is set to the ground potential, and the bias voltage that sets the plasma potential to +200 V is applied by the intermediate electrode (auxiliary electrode).
r Underlayer is formed and then CoCr ₁₂ Ta ₂ (at
%) Was used to form a Co alloy magnetic layer.

Next, in the second film forming chamber, a C protective layer having a thickness of 20 nm was formed under the condition of Ar gas pressure of 5 × 10 ⁻³ Toor. Then, in each example, film formation is performed on 100 substrates. The dropping rate of the substrate from the substrate holder and the arcing rate in the holding groove of the GL substrate were measured.
The results are shown in Table 2.

[0035]

[Table 2] ──────────────────────────────────── Example Comparative Example 4 5 6 7 3 4 Front view of substrate holding hole Fig. 2 Fig. 2 Fig. 2 Fig. 2 Fig. 2 Fig. 2 Center angle (a) (degree) 110 110 110 110 110 110 Cross section of holding groove Fig. 3 Fig. 3 Fig. 3 Fig. 3 Fig. 4 Opening Angle (b) (degree) 80 100 100 120 140 − Board penetration depth (c) (mm) 0.3 0.3 0.3 0.3 0.3 0.3 Board type AL AL AL GL AL AL GL ───────────── ─────────────────────── Substrate drop rate (%) 0 0 0 1 56 0 Arc generation rate (%) 0 38 ─────── ───────────────────────────── The central angle (a) represents the central angle in the arc of the substrate that contacts the substrate holder.

[0036]

According to the magnetic disk substrate holder of the present invention described above, an excellent magnetic disk capable of high density recording can be stably manufactured.

[Brief description of drawings]

FIG. 1 is a front explanatory view schematically showing an example of a magnetic disk substrate holder of the present invention.

2 is an enlarged front explanatory view of a substrate holding hole in the substrate holder shown in FIG.

FIG. 3 is a cross-sectional explanatory view of a holding groove provided in a substrate holding hole.

FIG. 4 is a cross-sectional explanatory view of a holding groove for comparison.

FIG. 5 is a schematic explanatory view of an example of a through film forming apparatus (sputtering apparatus).

FIG. 6 is a graph showing measurement results of changes in substrate temperature over time in Examples 1 to 3 and Comparative Examples 1 and 2.

[Explanation of sign]

 1: Substrate holder 11: Loading chamber 12: Heating chamber 13: First film forming chamber 14: Buffer chamber 15: Second film forming chamber 16: Discharge chamber 17: Return system 2: Plate-like body 3: Magnetic disk substrate 4: Substrate holding hole 41: V-shaped holding groove a: central angle b: opening angle c: magnetic disk substrate penetration depth

Claims (1)

[Claims] 1. A magnetic disk substrate holder (1) used for through film formation of a magnetic disk, comprising a plate-like body (2) vertically supported and conveyed in a through film forming apparatus. A plurality of substrate holding holes (4) for vertically holding (3) are provided, and a magnetic disk substrate (3) having a central angle (a) of 130 ° or less is provided on the bottom peripheral surface of the substrate holding holes (4). ), The opening angle (b) is 70 to 120 °, and the penetration depth (c) of the magnetic disk substrate (3) is 0.2 to 0.
A magnetic disk substrate holder having a V-shaped holding groove (41) of 4 mm.