Dynamic information storage or retrieval – Detail of optical slider per se
Reexamination Certificate
2000-06-02
2004-01-20
Watko, Julie Anne (Department: 2652)
Dynamic information storage or retrieval
Detail of optical slider per se
C369S112010
Reexamination Certificate
active
06680900
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to an optical-pickup slider using an optical near-field and floating a predetermined distance above a high-density recording medium by an air flow, and a manufacturing method thereof.
The present invention further relates to a probe suitable for gathering incident light and emitting it to a sample to be measured or a recording medium for example, and a manufacturing method thereof, a probe array and a manufacturing method thereof, and, in more detail, to a probe which can gather incident light and generate an optical near-field and/or propagation light, a manufacturing method thereof, a probe array and a manufacturing method thereof.
2. Description of the Related Art
In a high-density information recording device using an optical near-field, as shown in Japanese Laid-Open Patent Application No. 9-198830 for example, recording and reading of information is performed on a recording-medium disc in a condition in which a slider of an optical pickup (optical-pickup slider) floats a distance equal to or smaller than hundreds of nanometers above a surface of the recording-medium disc by an air flow generated due to rotation of the recording-medium disc. As shown in
FIG. 1
, a slider
61
disclosed in Japanese Laid-Open Patent Application No. 9-198830 has a conical hole
62
passing between a side facing a recording medium and an opposite side formed therein, and has an aperture
63
on the side facing the recording medium. Light is incident from a larger opening of the hole
62
and an optical near-field is generated in the vicinity of the aperture
63
.
As shown in
FIG. 2
, in a head of an information recording device using this slider
61
, a light source
11
and a lens
12
are provided on the side opposite to the side of the slider
61
facing the recording medium
14
. Light from the light source
11
is incident on the hole
62
of the slider
61
through the lens
12
. By this light, an optical near-field generated in the vicinity of the aperture
63
is incident on the recording medium. Light incident on the recording medium has a diameter on the order of a diameter of the aperture
63
, and it is possible to increase a resolution in recording/detecting, by this light, to one higher than 200 nm. Recording by this head is such that an energy applied to the recording medium
14
is changed, as a result of an intensity of light from the light source
11
being changed, and information is recorded on the recording medium
14
. Further, detecting of information is performed using a photodetector
64
arranged on a side of the recording medium
14
opposite to a side facing the slider
61
. Specifically, an optical near-field generated at the aperture
63
of the slider
61
generates propagation light as a result of contacting the recording medium
14
, and the propagation light is detected by the photodetector
64
, and, thus, information written on the recording medium can be detected. Thus, high-density recording can be performed using an optical near-field.
Further, M. B. Lee, T. Nakano, T. Yatsui, M. Kourogi, K. Tsutsui, N. Atoda, and M. Ohtsu, “Fabrication of Si planar aperture array for high speed near-field optical storage and readout”, Technical digest of the Pacific Rim Conference on Laser and Electro-Optics, Makuhari, Japan, No. WL2, pp. 91-92, July 1997 discloses, as shown in
FIG. 3
, a near-field optical probe
71
in which an inverse conical hole is formed in a silicon single-crystal substrate. When this probe
71
is made, a silicon single-crystal substrate
72
having thermal oxidation films
73
formed on both sides thereof, having a thickness of 270 &mgr;m and having (100) plane orientation, as shown in
FIG. 4A
, photo resist
74
is coated on the thermal oxidation films
73
, and an opening of 10 &mgr;m×10 &mgr;m is formed by photolithographic etching, as shown in FIG.
4
B. Then, as shown in
FIG. 4C
, single-crystal anisotropic etching of silicon is performed by KOH solution of 80° C. and a concentration of 10 weight %. Thereby, an inverse-pyramid-shaped hole
75
surrounded by a (111) plane of the silicon single-crystal substrate is formed. Then, as shown in
FIG. 4D
, photo resist
74
is coated on both sides, and a thermal-oxidation-film pattern having a large opening is made on the reverse side by photolithographic etching. Then, as shown in
FIG. 4E
, single-crystal anisotropic etching of silicon is performed from the reverse side by KOH solution again. At this time, the etching is stopped so that a through hole on the order of sub-microns is formed on the bottom of the pyramid-shaped hole
75
. The etching is stopped so that the opening dimension equal to or smaller than sub-microns can be obtained as a result of an etching speed being previously measured and a time of etching stoppage being controlled. Then, as shown in
FIG. 4F
, fringes of the thermal oxidation films are removed by a dicing saw or by etching. Then, as shown in
FIG. 4G
, gold
76
is spattered, and, thereby, laser light is prevented from being incident on a recording material through portions other than the openings. Further, for assuring that the etching is stopped just in time, as shown in
FIGS. 5A through 5G
, an SOI (Silicon-On-Insulator) substrate
78
having an SiO
2
film
77
in the middle is used. By this method, it is possible to obtain an opening having a diameter of 200 nm in a substrate.
An opening having a diameter equal to or smaller than 200 nm is formed on a side facing a recording medium in a slider disclosed in Japanese Laid-Open Patent Application No. 9-198830, and an evanescent wave is generated from this hole. However, this document does not disclose how to obtain this aperture, concretely. The slider has a thickness of millimeters in general, and it is not easy to form a very small aperture equal to or smaller than 200 nm through this thickness. Somewhat special technical measure is needed.
Further, the near-field optical probe shown in
FIG. 3
is made, as a result of, as shown in
FIGS. 4A through 4G
, the inverse-pyramid-shaped hole being formed by anisotropic etching, and, then, the large opening being formed by etching from the reverse side. In this case, the opening dimension of the minute hole is determined by the depth of etching from the reverse side. In order to stop the etching just in time so as to obtain the opening dimension of tens of nanometers, the etching time of the reverse side is previously measured, and, thereby, the etching time is determined. However, thickness of silicon substrates varies on the order of tens of microns among the substrates. Further, an etching speed varies in a wide range depending on an amount of silicon dissolved in an etching liquid, an amount of oxide dissolved in the etching liquid, a slight temperature difference, and so forth. Accordingly, it is actually very difficult to stop etching just in time so as to achieve an opening dimension of tens of nanometers from a previously measured etching speed and a substrate thickness.
It is possible to obtain a desired small opening on the order of 50 nm with high repeatability by using an SOI substrate, and using an SiO film embedded in the middle as a film for stopping etching from a reverse side, as shown in
FIGS. 5A through 5G
. However, a thick fringe is produced around a surface on which the small opening is produced. Thereby, in this condition, it is not possible that the opening approaches a recording medium to a distance of tens of nanometers. Therefore, it is necessary to remove this fringe. However, because a thickness of a portion having the opening is on the order of 10 &mgr;m, it is likely to be destroyed when or after the fringe is removed. In order to avoid such a situation, as shown in
FIG. 6C
or
FIG. 7C
, a thickness of a portion of a silicon substrate
72
in which an opening is provided is made small. Then, as shown in
FIG. 6E
or
FIG. 7E
, a pattern of silicon oxide for performing etching for providing the opening is formed on a bottom obtaine
Kourogi Motonobu
Ohtsu Motoichi
Takahashi Jun-ichi
Yatsui Takashi
Dickstein , Shapiro, Morin & Oshinsky, LLP
Ricoh & Company, Ltd.
Watko Julie Anne
LandOfFree
Optical-pickup slider, manufacturing method thereof, probe... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical-pickup slider, manufacturing method thereof, probe..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical-pickup slider, manufacturing method thereof, probe... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3218450