JPS5919255A - Electrostatic capacity type video disk reproducing stylus - Google Patents

Abstract

PURPOSE:To produce the titled stylus with high mass productivity and high production yield in the manufacturing stage, by forming a hard BN film having excellent wear resistance on an oxide substrate having rather low wear resistance by means of an ordinary thin film forming process and a pattern forming process to obtain desired thickness and form, and ensuring the wear resistance function with the BN thin film itself. CONSTITUTION:An R face sapphire 10 is used as a supporting substrate, and an Si3N4 film 11, a hard BN thin film 12 and an electrode film 13 containing Ti are used. The sapphire 10 in R plane with 2 inches phi is washed by an ordinary process, and the film 11 of about 0.2mum thickness is formed by a plasma CVD process. In this case, the temperature of substrate is set at about 600 deg.C with 0.2mum/h eduction speed. Then, the film 12 is formed by an ordinary RF sputtering process. In this case, the sputtering gas pressure is set at 4X10<-3> Torr with 0.7mum/h eduction speed, and the substrate is cooled by water. Finally, Ti is vapor deposited by an ordinary process, then the Ti electrode and the hard BN thin film are patterned by an ordinary photoetching technique.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a playback needle for capacitive video discs.

A conventionally known regenerated needle using bulk diamond will be explained with reference to FIG. FIG. 1 is a structural diagram of a regenerated needle tip that has been keeled. In the figure, 1 is a diamond substrate, 2 is a keel portion, 3 and ′ are first and second sliding surfaces, and 4 is an electrode formed on the entire surface of one side of the diamond substrate.

The electrode 11 of the keel part shown in FIG.
It is 40°.

Further, the functions of the keel portion are as shown below. The playback needle comes into contact with the disc during playback, so it gradually wears out.At the same time, the electrode also gradually retreats, but at that time, the electrode at the tip of the needle [IJ is always It is desirable to retreat so that it remains constant.

This is because the key point of the capacitance-based reproduction method is to pick up changes in the capacitance between the tip of the core pole 4 and the disk as changes in the information signal. However, if the electrode width changes due to wear due to contact with the recycled needle disk, the static capacitance between the disk and the regenerated needle tip will also change, resulting in faithful cleaning. It becomes impossible to reproduce the information signal.

As mentioned above, in the regenerated needle that has been keeled, it is necessary to uniformly form the polarization film on the regenerated needle up to the tip of the regenerated needle. According to 7", wax and the like adhere easily and are difficult to remove.

As mentioned above, not only the complexity of the mechanical grinding process, but also the complexity of the cleaning process before the formation of the i-electrode film leads to the lack of mass productivity of the regenerated needles and the decrease in the yield (yield: approx. 50%
).

The purpose of the present invention is to eliminate the drawbacks of the prior art described above, to provide a regenerated needle that can be mass-produced, and that can significantly reduce costs. I will explain using FIG. 2 is a perspective view of the tip of the four-injection needle according to the present invention. 5 in FIG. 2 is a support base made of oxide.

6 is a hard BN thin film, 7.7Tt first and second sliding surfaces 8
9 is a positive electrode, and 9 is a layer 5i or 5i3)b provided between the supporting base 5 and the hard IJN thin film 6.

That is, as shown in FIG. 2, the present invention is to deposit hard 13N'AIj soaked in wear resistance on an oxide substrate with poor wear resistance, such as glass or zaphire, using a conventional thin film. The hard BN thin 1JjK is processed into a desired film II and shape using a forming method and a pattern forming method, and the hard BN thin 1JjK itself is intended to have tab wear resistance. St provided between 6 and support 5
, is the 5i3Ni layer 9 necessary for the reasons stated below? [There is something 't'. In other words, as a result of a systematic study of the hard IJN8 film, it was found that a 'J-quality BN thin film 1.' cannot be formed on an oxide substrate, but a hard B/'Y thin film can be formed on Si, 5i3N4, etc. Understood.

:) On a dead oxide substrate 1. In order to form a hard BN thin film, it is necessary to use a 5i or 5i3Ni layer.

The pattern of the positive electrode 8 can be formed by a conventional thin film pattern forming method.

As described above, most of the manufacturing process of the thin film regeneration needle according to the present invention is a wafer processing process that is found in a normal IC manufacturing process.

-Also, regarding the lifespan of regenerated needles, by increasing the length of the part with the same peak width (as shown in Figure 2), the lifespan of the regenerated needles is equal to or longer than that of regenerated needles with conventional keel processing. I can hope for it.

The present invention will be explained in more detail using actual skill and needle measurement.

(Actual Example 1) The first embodiment will be explained using FIG. 6. FIG. 5 explains the new method of manufacturing the regenerated needle according to the present invention.
The process flow to achieve this is the worst.

10 in the figure is the 8-sided sapphire used as the annual support base.
11 is Si, 3N< film, 12 is hard BN thin film, 13 is T
The positive electrode consisting of i) is a sample.

As shown in FIG. 5, a 2-inch φR surface sapphire was cleaned by a conventional method, and a 5isN4 film was formed to a thickness of about 0.2μ2n by plasma CVD. The substrate temperature during formation is approximately 6
At 00'C the deposition rate is 0.2 μm/h. Thereafter, a hard BN thin film was formed using a conventional RF sputtering method.

Sputtering gas during formation, If is 4X10 To
rγ, the deposition rate was 0.7μ771/A, and the substrate was water-cooled. Finally, Ti was deposited using the usual Makabe deposition method.

After that, Ti'+i is etched by normal photoetching technique.
Extremely hard H, l'! The thin films were sequentially vacuumed into the shape shown in FIG. The etching method for fi is an ion etching method using Aγ, and the etching method for the hard BN film is a reactive spasota etching method using a CF4 gas.

The above-mentioned steps are all wafer processing steps.

After patterning the BN thin film, the chips were divided into chips using a high-speed die-to-die, and the support was processed.

Approximately 500 recycled needles can be made from a 2-inch φ' wafer, and the yield rate is approximately 80%.

The regenerated needle made by the method described above was installed in the pickup system, and the re-hoistability and lifespan of No. G were examined, and it was found that the regenerated needle had almost the same performance as the conventional regenerated needle.

(Example 2) Even when 5i was used in place of 5L3N4 in the first example, results equivalent to those in the first example were obtained.

As explained above, according to the present invention, mass productivity is good and yield rate in the manufacturing process is improved! It is possible to provide a stationary capacitance type regenerated needle with good efficiency.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a conventional recycled needle tip mainly made of bulk diamond, Fig. 2 is a perspective view of a recycled needle tip of an embodiment of the present invention, and Fig. 5 is a flowchart of the recycled needle manufacturing process. It is. 1...Diamond base, 2...Giel part. 5.3'...First and second sliding surfaces, 4...Electrode, 5...Supporting base made of oxide, 6...Hard BN thin film, 7.7'...First ．． second sliding surface, 8... electrode; ? ...SL or 5isNt layer, 10...Sapphire substrate, 71...Sε! A'4 film, 12... Hard BN thin film, 15... Ti film. Side and dimensions 1

Claims (1)

[Claims] 1. In a reproducing needle that relatively scans a medium on which an information signal is recorded as a change in geometrical shape and detects the information signal as a change in static capacitance, at least a part of the reproducing needle is characterized by comprising a support base made of an oxide, a hard BN thin film, and an electrode, and at least one of a Si layer or a Si3N4 layer is interposed between the support base and the hard BN thin film. Playback needle for capacitive video discs.