JPS5914154A - Electrode forming method of scanning stylus - Google Patents

Abstract

PURPOSE:To form with high accuracy an electrode having high mechanical strength and large adhesive strength to a basement, by making use of the graphite phase obtained when a groove is formed with laser processing of diamond to form a carbide of electrode material and then to obtain an electrode layer. CONSTITUTION:The tip part of a diamond basement 1 is formed into a pyramid shape. This basement 1 is divided at its ridgeline 2 to form run-in side surfaces 3 and 4 together with a run-out side surface 5 and a scanning surface 6. A groove 8 is formed on the surface 5 by irradiating thin beams of Nd:YAG laser in the lengthwide direction in an inactive gas. Then a graphite phase 11 is formed at the groove 8, and an electrode film 12 is formed on the surface 5 by vapor depositing Ti or Hf. Then a heat treatment is carried out under vacuum for 6-24hr and at 400-900 deg.C to obtain an electrode film 14 of titanium carbide. In such a way, the mechanical strength is increased together with increment of adhesive force to the basement 1 and high accuracy for the electrode 12.

Description

[Detailed Description of the Invention] Field of the Invention This invention relates to a method for forming a scanning needle electrode, which is used together with a recording medium to stably fix the electrode on a base for extracting recorded information as a change in capacitance value. PRIOR ART An enlarged view of the main part of 70 as a scanning needle applied to this type of recording medium, for example, a VHD format video disc, is shown in Figure 1.
The proposed method shown in the figure is -C. This (/J) scanning needle is equipped with a needle base (A) made of a hard and brittle material such as diamond (or diamond) and an electrode layer (B) of a high melting point metal such as titanium or hafnium. At the tip of the stand (A) is a scanning surface (C) shaped to align with the recording medium.
Then, draw a picture 55. around this running surface. Five descending sides (Dl
) to (D5), and an electrode layer (B)'2 is provided on the side surface (D1)k on the running side. Incidentally, in this scanning needle, the width (Fj) of the electrode layer (B) is set to a specified value T by forming (machining) the side surfaces (D2) and (D5). The electrode width (E) is less than f within the track of the recording medium.
It is extremely difficult to maintain a predetermined yield rate and reduce the processing time because it is necessary to reduce the thickness by approximately 1 μm or less.

On the other hand, the thickness F) of the IN layer CB) is less than the shortest wavelength of the recorded information (for example, 1500 to 2'5004), but has a size of about 4 with respect to the electrode width. 0) Since the contact area between the electrode layer (B) and the burr base (A) is minute, the impact energy of the abrasive grains during processing and the resulting repetitive stress may be caused by the vibration of the polishing machine, etc. There is a risk of peeling due to the energy generated by 1. In order to prevent this from rain, it is also considered that the electrode (B) be attached to the needle base (A) by ion implantation, which has a relatively long adhesion strength.

However, this ion implantation method requires expensive equipment and it is difficult to accurately perform processing to specify the electrode width, so there is a limit to the yield. Furthermore, when the anti-T filter electrode is attached to the needle base by vapor deposition or sputtering, there are disadvantages such as insufficient adhesion strength because the area for attachment is small.

Problems of the invention To solve the above-mentioned drawbacks, to accurately and easily regulate T7'r, that is, the electrode width, and to improve the adhesion strength lfw of the electrode layer to the needle base by a simple method such as vapor deposition. The present invention is intended to provide a method for forming the electrodes of the scanning needle, which contributes to the development of the present invention.

Structure of the Invention The present invention provides a recording medium for a diamond scanning needle base.
irradiate the running side surface with a laser beam in an inert atmosphere to form grooves of a predetermined width in the longitudinal direction of the surface and a graphite phase of diamond facing the grooves (first step), including the groove surface. An electrode gold layer is attached to the surface of the running side (Step 2). Next, it is heated in a vacuum atmosphere to grow a metal compound layer consisting of the graphite phase and the metal electrode layer (Step 3).

The electrode film of the scanning needle is then removed from the part of the surface on the scanning side except for the single groove area (step 4).

Embodiments of the Invention FIG. 2 is a perspective view of the tip of a scanning needle manufactured by the method of the present invention, FIG.
．． 1! It is a cross-sectional view of a portion corresponding to the cross section (X-X) of the scanning needle in Figure 2 for explaining the 5th step.

As shown in Figure 2, the scanning needle is made of diamond.A natural diamond (an artificial diamond attached to the shank will also work)
is used as a starting material, the tip thereof is formed into a triangular pyramid shape, and a pair of entry side surfaces +31+41 and exit side surfaces (5) separated by a ridge line 12+ descending to the recording medium is provided. Crotch the descending scanning plane (6) aligned with the
r, U(2. Set 1 surface L''11 k +
It is provided with grooves (8) extending in two longitudinal directions (7), and electrodes 1irilO) are embedded in the grooves. Next, the method for forming this electrode will be explained with (:).

First step (G in the third diagram): A Nd:YAO laser with a sufficiently narrowed beam spot diameter in an inert atmosphere is applied to the exit side surface (5)L of the E-shaped base +l+ as described above in the longitudinal direction. By irradiating the groove f8
When forming j 'i', 1 diamond is transformed into graphite in the groove portion laser-processed by the thermal energy of the laser beam. A graphite phase (11) is formed. Treatment in an inert atmosphere (argon or nitrogen atmosphere) helps prevent oxidative combustion of this graphite phase, and a well-narrowed beam spot precisely defines the electrode width.

Second step (see FIG. 4): Titanium (or hafnium) is applied by vapor deposition (or sputtering) on the running side surface (5) provided with the grooves (8) in this way. (12
1 is an attached electrode film, and the thickness 131 is 1500~2
It is about 5ooA% (plot L, this thickness is exaggerated).

9A5 step (see Figure 5)
' Insertion of true stenosis 5C below Torr, 400~9
A heating treatment is performed at a temperature of 00° C. for 6 to 24 hours.

This results in a two-electrode film (121) and a graphite phase (Ill
is chemically reacted and a new titanium carbide electrode film 04 is created.
-(1゜This new electrode film a4 is very hard and has a reaction layer Yf'lE at the interface with the diamond, so its adhesion strength is very strong.If the heat treatment temperature is lower than 400℃, the metal Difficulties occur in the formation of nitrides, while 900
℃, the mechanical strength of titanium, which is the electrode film material, decreases.

4th step (@ Figure 5): Using a lapping machine or the like, polish the material that has been heat treated in this way up to the T portion indicated by the broken line 05 in Figure @ 5 (#76), and so on.

The running side surface 051 is newly exposed T;6. Thereby, an electrode layer (14) is formed on the base (1). Furthermore, this electrode layer.

The metal nitride phase, which is a chemical reaction product between the electrode metal provided in the grooves (8) and the graphite phase of diamond generated during forming the grooves, is contained entirely or in the middle.

In the wood example, the electrodes were formed on a base that had undergone the specified processing necessary for the scanning needle, but after forming the electrodes on the specified portions of the base material, the Needless to say, it's a good thing.

Effects of the Invention In the present invention, since the electrode width is defined at the same time when the laser beam moves down the groove i, it is possible to regulate the electrode width T with high precision.

In addition, by utilizing the graphite phase of diamond that is formed during groove processing with a laser beam, electric wires that are attached to the purchased metal using normal attaching methods (e.g., vapor deposition sputtering, etc.) can be used.
Since a carbide of the electrode material is prepared and used as the electrode layer, an electrode with high mechanical strength and strong adhesion to the base can be formed.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the tip of a conventional scanning needle. @2
The figure is a perspective view of the tip of a threading needle manufactured by the method of the present invention. i! Figure g5, Figure 4, and Figure @5 are the first stages of electrode formation.
6 2nd. To explain the 5th step, cross section of @2 figure (
It is a sectional view corresponding to XX)-2. Explanation of main drawing numbers (1)...Base, α frame...electrode layer, (8)...groove, old)...graphite phase. Figure 2

Claims (1)

[Claims] (1) T to the recording medium of the diamond scanning needle base
The scanning needle base is irradiated with a laser beam in an inert atmosphere to remove grooves T corresponding to the width of the electrode and the graphite phase facing the grooves in the longitudinal direction of the scanning needle base. The first step is the 1st step of attaching an electrode metal to the running side surface including the groove surface, and the second step is heating the material in a Makabe atmosphere. Grow a metal carbide layer with the graphite phase and the electrode metal film in 6 steps.
＠Remove the part excluding the groove area with the electrode metal film attached to the surface on the running side T7:I! A scanning needle electrode forming method comprising four steps.