Semiconductor device manufacturing: process – Making device or circuit responsive to nonelectrical signal – Physical stress responsive
Reexamination Certificate
2002-04-25
2003-02-25
Niebling, John F. (Department: 2812)
Semiconductor device manufacturing: process
Making device or circuit responsive to nonelectrical signal
Physical stress responsive
C438S456000, C310S309000
Reexamination Certificate
active
06524878
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to microactuators, methods for making the same, and magnetic head units and magnetic recording apparatuses using the same. In particular, the present invention relates to a method for making a microactuator which is assembled in magnetic head units and is suitable for precise alignment of the position of the magnetic head.
2. Description of the Related Art
A magnetic recording apparatus generally has a magnetic recording medium having a data-recording surface, such as a magnetic disk, a magnetic head for writing information into and reading the information from the magnetic recording medium, a head holder including a slider and a gimbal for supporting the magnetic head, and a head driver such as a voice coil motor for driving the head holder in order to align the position of the magnetic head with respect to a required track on the magnetic recording medium. In the alignment of the position of the magnetic head by the voice coil motor, current voice coil motors reach the limits of the alignment precision in consideration of a trend towards a finer track width. Thus, a proposed method is a combination of coarse adjustment of the head position using the voice coil motor and then fine alignment using a high-precision actuator.
FIGS. 7 and 8
show an example of a conventional actuator having high precision and capable of being finely movable. The actuator
101
shown in
FIGS. 7 and 8
is generally called an electrostatic actuator which is driven by an electrostatic attractive force. The electrostatic actuator
101
includes two glass substrates, i.e., a first substrate
102
and a second substrate
103
, facing each other with a given distance and movable with respect to each other in the horizontal direction. The first substrate
102
has a first comb electrode
104
having a plurality of comb elements
104
a
which are parallel to each other on an inner face
102
a
thereof, whereas, the second substrate
103
has a second comb electrode
105
having a plurality of comb elements
105
a
which are parallel to each other on an inner face
103
a
thereof. The comb elements
104
a
and the comb elements
105
a
are alternately arranged.
When a voltage is applied between the first electrode
104
and the second electrode
105
in the above electrostatic actuator
101
, the comb elements
104
a
of the first electrode
104
and the comb elements
105
a
of the second electrode
105
are deeply engaged with each other by the electrostatic attractive force generated between the first electrode
104
and the second electrode
105
. Thus, the first electrode
104
approaches the second electrode
105
so that the first substrate
102
and the second substrate
103
move with respect to each other. When the voltage is cut, the engagement is released due to the removal of the electrostatic attractive force. Thus, the first electrode
104
withdraws from the second electrode
105
so that the first substrate
102
and the second substrate
103
move with respect to each other in the reverse direction.
A conventional manufacturing process of the above electrostatic actuator
101
will be described with reference to
FIGS. 9A
to
9
H. Referring to
FIG. 9A
, a resist film
201
having a predetermined pattern is formed on the upper surface and a resist film
202
is formed on the entire lower surface of a conductive silicon wafer
200
. The conductive silicon wafer
200
is etched through the resist film
201
as a first mask, and then the resist films
201
and
202
are removed. A silicon wafer
200
B having an outer shape shown in
FIG. 9B
is prepared. A resist film
203
is formed on the entire upper surface of the silicon wafer
200
B and a resist film
204
having a predetermined pattern is formed on the lower surface of the silicon wafer
200
B, as shown in FIG.
9
C. The silicon wafer
200
B is etched through the resist film
204
as a second mask, and then the resist films
203
and
204
are removed. A silicon wafer
200
C having predetermined patterns on the two surfaces thereof is thereby prepared, as shown in FIG.
9
D.
With reference to
FIG. 9E
, the silicon wafer
200
C is bonded to a second glass substrate
103
provided with a predetermined wiring pattern (not shown in the drawing) of a metal such as aluminium, which is preliminarily formed using a third mask (not shown in the drawing), by an anodic bonding process to form a semi-finished product. A resist film
205
having a predetermined pattern is formed on the upper face of the silicon wafer
200
C, as shown in
FIG. 9F
, and the silicon wafer
200
C is etched through the resist film
205
as a fourth mask until the silicon wafer
200
C is completely removed at unmasked regions. The resist mask
205
is removed to form electrode precursors
105
B for the second electrodes on the second substrate
103
and electrode precursors
104
B for the first electrodes, as shown in
FIG. 9G
, in which the electrode precursors
105
B are connected to the electrode precursors
104
B in the boundary regions (not shown in the drawing).
With reference to
FIG. 9H
, the electrode precursors
104
B are bonded to a first glass substrate
102
having a predetermined wiring pattern of a metal such as aluminium, which is preliminarily formed using a fifth mask (not shown in the drawing), by an anodic bonding process to form the microactuator shown in
FIGS. 7 and 8
.
As described above, this manufacturing process needs five masks. A reduction in the number of masks and steps in this process would produce actuators with further reduced manufacturing costs.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a microactuator capable of reducing the number of masks in the production process and simplifying the production process, and a method for making the microactuator.
It is another object of the present invention to provide a magnetic head unit and a magnetic recording apparatus using the microactuator.
A microactuator in accordance with the present invention comprises a first substrate, a second substrate, the first substrate and the second substrate facing each other with a distance and movable with respect to each other, a first comb electrode having a plurality of first comb elements formed on an inner surface of the first substrate, a second comb electrode having a plurality of second comb elements formed on an inner surface of the second substrate, the first comb elements and the second comb elements being alternately disposed, and a connecting film formed by partially removing an interlayer formed on the inner face of any one of the first substrate and the second substrate, any one of the first electrode and the second electrode being bonded to the connecting film.
A method for making a microactuator in accordance with the present invention comprises providing a first substrate and a second substrate facing each other with a distance and movable with respect to each other, and providing a first comb electrode having a plurality of first comb elements formed on an inner surface of the first substrate and a second comb electrode having a plurality of second comb elements formed on an inner surface of the second substrate, wherein a wafer comprising two substrate layers and an interlayer provided therebetween is used as any one of the first substrate and the second substrate and one of the two substrate layers is etched using a mask having a predetermined pattern to form a first electrode precursor group and a second electrode precursor group for the first electrodes and the second electrodes, respectively, the interlayer below any one of the first and second electrode precursor groups is removed by etching to form any unconnected one of the first and second electrodes and to form the other one of the first and second electrodes supported by connecting films formed by etching of the remaining interlayer, and said unconnected one is bonded to the other one of the first substrate and the second substrate.
In the microac
Abe Munemitsu
Esashi Masayoshi
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Niebling John F.
Simkovic Viktor
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