JPS61104082A - Device for plating magnetic disk substrate - Google Patents

Abstract

PURPOSE:To obtain the titled device capable of electroless-plating a substrate without any defects by rotating circumferentially an oscillating shaft having a recessed groove for supporting plural magnetic disk substrates in a treating vessel with an ultrasonic vibrator on the outside surface. CONSTITUTION:An oscillating shaft 3 consisting of two circular surface 8 and 9 each having a different radius of curvature is protruded from the lower end of a T-shaped frame 4 in an electroless nickel plating liq. 30 in a treating vessel 1 lined with a polyfluoroethylene layer 2, and plural recessed grooves 10 are furnished to the shaft to support plural magnetic disk substrates 20 in parallel, and out of contact with each other. The frame 4 is rotated by a revolving plate 6 through a bearing 5 and a crank pin 7, the oscillating shaft 3 is rotated and allowed to follow a cricumferential course, and the substrate 20 is rotated around the oscillating shaft 3 having a non-circular cross section. An auxiliary vessel 11 is further provided, and ultrasonic vibration is produced by a vibrating plate 12 attached to the outer side surface of the treating vessel 1 and an ultrasonic vibrator 13. Consequently, the whole outer surface of the substrate 20 is plated without any defects such as pits.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a plating apparatus for magnetic disk substrates, which is used to perform defect-free electroless plating on the entire outer surface of a magnetic disk substrate.

(Prior Art) A magnetic disk used in a storage device of an information processing system is formed by forming a nickel plating layer with a thickness of about 10 μm as an underlayer on the upper surface of a magnetic disk substrate made of an aluminum alloy, and then forming a magnetic recording layer on top of it. Furthermore, the top surface is covered with a protective layer, and electroless nickel plating is widely used to form this nickel plating layer. However, during this electroless nickel plating process, hydrogen gas bubbles are generated on the surface of the magnetic disk substrate due to a chemical reaction, and if left untreated, uneven plating will occur. A plating device was used that applied vibrations to remove air bubbles.

(Problem to be Solved by the Invention) However, in the conventional magnetic disk substrate plating apparatus as described above, fine air bubbles cannot be completely removed, so microscopic concavities called spots are formed on the surface of the magnetic disk substrate. Problems that result in defects.

There was also the problem that plating could not be performed on the contact area between the magnetic disk substrate and its support jig.

(Means for Solving the Problems) The present invention has been completed in order to solve the problems of the conventional technology, and includes a non-circular cross-section that revolves in a circumferential trajectory inside the processing tank. A swing shaft is provided, and a plurality of grooves for supporting a plurality of magnetic disk substrates are formed on the circumferential surface of the swing shaft, and an ultrasonic vibrator is installed on the outer surface of the processing tank parallel to the swing shaft. It is characterized by having a.

(Example) Next, the present invention will be explained in detail with reference to the illustrated example.
'+1) has a polyfluoroethylene lining layer (
2) is a processing tank made of a corrosion-resistant material such as stainless steel, (3) is a swinging shaft installed horizontally or slightly inclined inside the processing tank (1), and (20) is the swinging shaft. (3
) is a plurality of magnetic disk substrates supported by. The swing shaft (3) is provided protruding from the lower end of the T-shaped support frame (4), and the rotating disc is attached to the optical bearings (5), (5) provided at both ends of the upper part of the support frame (4). Since the crank pins (7) and (7) of (6) and (6) are fitted, if the rotary disks (6) and (6) are rotated at a speed of about 7ORPM, the swing shaft (3) will move. It will revolve in a circumferential trajectory. As shown in the figure, the swing shaft (3) has a non-circular cross section formed by two arcuate surfaces (8) and (9) with different radii of curvature, and its maximum diameter is the center hole of the magnetic disk substrate (20). (21), and has a plurality of concave grooves α on its circumferential surface for supporting a plurality of magnetic disk substrates (20) in parallel so that they do not come into contact with each other.
ω is formed with a width slightly wider than the thickness of the magnetic disk substrate (20). The inside of the processing tank (11 has a liquid temperature of 80~
It is filled with an electroless nickel plating solution (30) at 90°C. (11) is an auxiliary tank provided as necessary on the outer surface parallel to the swing axis (3) of the processing tank (1), and the outer surface has a diaphragm (12) and a plurality of ultrasonic vibrations. Child (13)
is installed. Cooling water (31) is provided inside the auxiliary tank (11) by a water supply pipe (14) and a drain pipe (15).
is supplied so that it can be circulated, and the heat of the processing tank (1) is prevented from being transmitted to the ultrasonic transducer (13), but the auxiliary tank (11) is omitted and the processing tank (1) is Even if the ultrasonic transducer (13) is attached directly to the outer surface = 1″0゛・

1゜(Function) In this structure, the center holes (21) of the plurality of magnetic disk substrates (20) are fitted into the plurality of grooves (10) on the circumferential surface of the swing shaft (3). Support the turntable (6), (
If the swing shaft (3) is made to revolve in a circumferential trajectory by rotating 6), the swing shaft (3) will rotate as shown in Fig. The center hole (21) of the magnetic disk substrate (20) rotates while maintaining an almost constant relationship by only slightly changing the contact point within the range shown by R, but the rotation speed is set to 7ORP.
If it is about M, as shown in Fig. 4, the magnetic disk substrate (20)
could not follow the contact point and moved downward, and when the swing shaft (3) further moved to the D position, it collided upward with the left inner surface of the center hole (21), causing the magnetic disk board to drop to about 15 PPM. It will rotate clockwise at the same speed. As a result, the magnetic disk substrate (20) rotates inside the processing tank (1) while largely moving the point of contact with the swing shaft (3) as shown by R in the figure, and its entire outer surface is coated with electroless nickel. It will be plated. At this time, hydrogen gas bubbles are generated on the surface of the magnetic disk substrate (20), but the ultrasonic vibrator (13) attached to the outer surface parallel to the swing axis (3) of the processing tank (11) Since ultrasonic vibrations are applied to the electroless nickel plating solution (30) in the processing tank (1), hydrogen gas bubbles on the surface of the magnetic disk substrates (20) are completely removed by the ultrasonic vibrations transmitted between the magnetic disk substrates (20). Electroless nickel plating without defects such as focus will be applied.

Note that standing waves caused by ultrasonic waves are generated inside the processing tank (1), which tends to cause cavitation effects to vary in strength, but since the magnetic disk substrate (20) is rotating as described above, hydrogen gas bubbles are The entire surface is completely removed.

(Effects of the Invention) As is clear from the above description, the present invention enables uniform electroless plating without defects such as pits to be applied to the entire outer surface of a magnetic disk substrate, and it is possible to apply uniform electroless plating to the entire outer surface of a magnetic disk substrate. It will greatly contribute to the development of industry by solving the problems of substrate plating equipment.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention, FIG. 2 is a partially cutaway side view thereof, and FIGS. 3 and 4 are explanatory views of the operation of the swing shaft. (1): Processing tank, (3): Swing shaft, (10): Concave groove,
(13): Ultrasonic transducer, (20): Magnetic disk substrate. t:ea meeting

Claims (1)

[Claims] A swing shaft (3) with a non-circular cross section that revolves in a circumferential trajectory is provided inside the processing tank (1), and a plurality of magnetic disk substrates (20) are mounted on the circumferential surface of the swing shaft (3). A plurality of grooves (10) are formed to support the processing tank (1), and an ultrasonic vibrator (13) is attached to the outer surface of the processing tank (1) parallel to the swing axis (3). Magnetic disk substrate plating equipment.