U.S. patent application number 12/704620 was filed with the patent office on 2011-01-13 for stacked-type piezoelectric device and method for manufacturing the same.
This patent application is currently assigned to INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE. Invention is credited to Wen-Chih Chen, Huan-Chun Fu, Tsung-Fu Tsai.
Application Number | 20110006645 12/704620 |
Document ID | / |
Family ID | 43426933 |
Filed Date | 2011-01-13 |
United States Patent
Application |
20110006645 |
Kind Code |
A1 |
Chen; Wen-Chih ; et
al. |
January 13, 2011 |
STACKED-TYPE PIEZOELECTRIC DEVICE AND METHOD FOR MANUFACTURING THE
SAME
Abstract
A stacked-type piezoelectric device includes a stack of
piezoelectric layers, plural conductive layers, a first contact
hole, a second contact hole, and plural insulating portions. The
piezoelectric layers are disposed between the conductive layers.
The first and second contact holes penetrate the piezoelectric
layers and the conductive layers, and each of first and second
contact holes is filled with a conductive material. Every
insulating portion is formed at one conductive layer. Two adjacent
insulating portions are respectively formed at the outer rims of
the first and second contact holes, to electrically isolate the
conductive layer (in which the insulating portion is formed) from
the conductive material in the contact hole.
Inventors: |
Chen; Wen-Chih; (Hsinchu
County, TW) ; Tsai; Tsung-Fu; (Yunlin County, TW)
; Fu; Huan-Chun; (Hsinchu City, TW) |
Correspondence
Address: |
THOMAS, KAYDEN, HORSTEMEYER & RISLEY, LLP
600 GALLERIA PARKWAY, S.E., STE 1500
ATLANTA
GA
30339-5994
US
|
Assignee: |
INDUSTRIAL TECHNOLOGY RESEARCH
INSTITUTE
Hsinchu
TW
|
Family ID: |
43426933 |
Appl. No.: |
12/704620 |
Filed: |
February 12, 2010 |
Current U.S.
Class: |
310/366 ;
29/25.35 |
Current CPC
Class: |
H01L 41/083 20130101;
H01L 41/0474 20130101; Y10T 29/42 20150115; H01L 41/273
20130101 |
Class at
Publication: |
310/366 ;
29/25.35 |
International
Class: |
H01L 41/047 20060101
H01L041/047; H01L 41/24 20060101 H01L041/24 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 10, 2009 |
TW |
98123514 |
Claims
1. A piezoelectric unit structure, comprising: a piezoelectric
layer, having an upper surface and a lower surface; a first
conductive layer and a second conductive layer, respectively
located on the upper and lower surfaces of the piezoelectric layer;
a first contact hole, penetrating the piezoelectric layer; a second
contact hole, penetrating the piezoelectric layer; and at least an
insulating portion formed in one of the first and second conductive
layers and surrounding one of the first and second contact holes,
for isolating the contact hole from the conductive layer in which
the insulating portion is formed.
2. The piezoelectric unit structure according to claim 1, wherein
the first contact hole penetrates one side of the first conductive
layer, the piezoelectric layer and the second conductive layer, and
the second contact hole penetrates the other side of the first
conductive layer, the piezoelectric layer and the second conductive
layer.
3. The piezoelectric unit structure according to claim 2, wherein
the first contact hole and the second contact hole are
perpendicular to the first conductive layer, the piezoelectric
layer and the second conductive layer respectively.
4. The piezoelectric unit structure according to claim 2 further
comprising another insulating portion, wherein the two insulating
portions are respectively formed on the first conductive layer and
the second conductive layer on the upper and lower surfaces of the
piezoelectric layers, and the two insulating portions respectively
surround the outer rims of the first and second contact holes of
the conductive layers.
5. The piezoelectric unit structure according to claim 2, wherein
the first and second contact holes are filled with a conductive
material.
6. The piezoelectric unit structure according to claim 5 further
comprising an insulation sidewall connected to the insulating
portion and located between the piezoelectric layer and the
conductive material, for electrically isolating the piezoelectric
layer and the conductive material in the contact hole.
7. The piezoelectric unit structure according to claim 5
comprising: a first insulating portion, formed in the first
conductive layer and at the outer rim of the first contact hole, to
electrically isolate the first conductive layer from the conductive
material in the first contact hole; and a second insulating
portion, formed in the second conductive layer and at the outer rim
of the second contact hole, to electrically isolate the second
conductive layer from the conductive material in the second contact
hole.
8. The piezoelectric unit structure according to claim 7 further
comprising: a first insulation sidewall, connected to the first
insulating portion and electrically isolating the conductive
material in the first contact hole from the piezoelectric layer;
and a second insulation sidewall, connected to the second
insulating portion and electrically isolating the conductive
material in the second contact hole from the piezoelectric
layer.
9. The piezoelectric unit structure according to claim 8, wherein
an end of the first insulation sidewall is aligned with the lower
surface of the piezoelectric layer, and an end of the second
insulation sidewall is aligned with the upper surface of the
piezoelectric layer.
10. A multi-layer stacked-type piezoelectric device, comprising: a
plurality of piezoelectric units stacked together, each of the
piezoelectric units comprising: a piezoelectric layer, having an
upper surface and a lower surface; a first conductive layer and a
second conductive layer, respectively located on the upper and
lower surfaces of the piezoelectric layer; a first contact hole and
a second contact hole, respectively penetrating two lateral sides
of the first conductive layer, the piezoelectric layer and the
second conductive layer, wherein the first contact hole and the
second contact hole are filled with a conductive material; and a
first insulating portion and a second insulating portion,
respectively formed on the first and second conductive layers on
the upper and lower surfaces of the piezoelectric layer and located
at the outer rims of the first and second contact holes, for
electrically isolating the conductive layer in which the insulating
portions are formed from the conductive material in the contact
hole; wherein in the multi-layer stacked-type piezoelectric device,
the first or second insulating portion of each piezoelectric unit
corresponds to and contacts the first or second insulating portion
of another piezoelectric unit.
11. The multi-layer stacked-type piezoelectric device according to
claim 10, wherein each piezoelectric unit further comprises: a
first insulation sidewall, connected to the first insulating
portion and electrically isolating the conductive material in the
first contact hole from the piezoelectric layer; and a second
insulation sidewall, connected to the second insulating portion and
electrically isolating the conductive material in the second
contact hole from the piezoelectric layer.
12. The multi-layer stacked-type piezoelectric device according to
claim 10, wherein in each piezoelectric unit, an end of the first
insulation sidewall is aligned with the lower surface of the
piezoelectric layer, and an end of the second insulation sidewall
is aligned with the upper surface of the piezoelectric layer.
13. The multi-layer stacked-type piezoelectric device according to
claim 10, wherein the conductive material is a conductive
adhesive.
14. The multi-layer stacked-type piezoelectric device according to
claim 10, wherein the conductive material is silver paste.
15. The multi-layer stacked-type piezoelectric device according to
claim 10, wherein the materials of the first and second insulating
portions comprise epoxy.
16. A stacked-type piezoelectric device, comprising: a plurality of
piezoelectric layers; a plurality of conductive layers, formed
between the piezoelectric layers; a first contact hole and a second
contact hole, respectively penetrating the piezoelectric layers and
the conductive layers, wherein the first and second contact holes
are filled with a conductive material; and a plurality of
insulating portions, formed in the conductive layers
correspondingly, and two adjacent insulating portions respectively
located at the outer rims of the first contact hole and the second
contact hole, for electrically isolating the conductive layer in
which the insulating portion is formed from the conductive material
in the contact hole.
17. The multi-layer stacked-type piezoelectric device according to
claim 16 further comprising n piezoelectric layers and (n+1)
conductive layers, wherein n is a positive integer not less than 2,
the insulating portions on the odd-numbered conductive layers are
corresponding to the outer rim of the first contact hole, and the
insulating portions on the even-numbered conductive layers are
corresponding to the outer rim of the second contact hole.
18. The multi-layer stacked-type piezoelectric device according to
claim 16 further comprising: a plurality of insulation sidewalls
disposed between the piezoelectric layers and the first and second
contact holes, for electrically isolating the piezoelectric layer
from the conductive material in the contact hole in which the
insulation sidewalls are formed.
19. The multi-layer stacked-type piezoelectric device according to
claim 16, wherein the insulation sidewalls are connected to the
adjacent insulating portions respectively.
20. The multi-layer stacked-type piezoelectric device according to
claim 16, wherein the conductive material is a conductive
adhesive.
21. The multi-layer stacked-type piezoelectric device according to
claim 20, wherein the conductive material is silver paste.
22. The multi-layer stacked-type piezoelectric device according to
claim 16, wherein the material of the insulating portions comprises
epoxy.
23. A method for manufacturing a single-layer piezoelectric device,
the method comprising: providing a piezoelectric layer having an
upper surface and a lower surface; forming a first conductive layer
and a second conductive layer respectively on the upper and lower
surfaces of the piezoelectric layer; forming a first contact hole
and a second contact hole respectively penetrating the first
conductive layer, the piezoelectric layer and the second conductive
layer; forming a first insulating portion and a second insulating
portion respectively on the first and second conductive layers, and
the first and second insulating portions respectively located at
the outer rims of the first and second contact holes; and filling a
conductive material in the first and second contact holes; wherein
the first insulating portion electrically isolates the first
contact hole from the first conductive layer, and the second
insulating portion electrically isolates the second contact hole
from the second conductive layer.
24. The method according to claim 23 further comprising: forming a
first insulation sidewall between the first contact hole and the
piezoelectric layer, the first insulation sidewall connected to the
first insulating portion; and forming a second insulation sidewall
between the second contact hole and the piezoelectric layer, the
second insulation sidewall connected to the second insulating
portion.
25. The method according to claim 24, wherein after the step of
providing the piezoelectric layer, a first penetrating hole and a
second penetrating are formed on two lateral sides of the
piezoelectric layer; filling an insulating material in the first
and second penetrating holes; forming the first and second
conductive layers respectively on the upper and lower surfaces of
the piezoelectric layers; drilling on the places corresponding to
the first and second penetrating holes for forming the first and
second contact holes, the diameter of the first and second contact
holes being less than that of the first and second penetrating
holes to form the first and second insulation sidewalls; removing a
portion of the first conductive layer corresponding to the outer
rim of the first contact hole, and removing a portion of the second
conductive layer corresponding to the outer rim of the second
contact hole; filling the insulating material in the first and
second contact hole; drilling the first and second contact holes
for leaving the insulating material at the outer rims of the first
and second contact holes to form the first and second insulating
portion; and filling the conductive material in the first and
second contact holes.
26. The method according to claim 23, wherein after the step of
providing the piezoelectric layer, the first and second conductive
layers are respectively formed on the upper and lower surfaces of
the piezoelectric layer; forming a first and a second penetrating
holes respectively penetrating two lateral sides of the first
conductive layer, the piezoelectric layer and the second conductive
layer; removing a portion of the first conductive layer
corresponding to the outer rim of the first penetrating hole, and
removing a portion of the second conductive layer corresponding to
the outer rim of the second penetrating hole; filling an insulating
material in the places corresponding to the first and second
penetrating holes, the insulating material fully filled in the
removed portion of the first and second conductive layers; drilling
the first and second penetrating holes for forming the first and
second contact holes, the diameter of the first and second contact
holes being the same as that of the first and second penetrating
holes, wherein after the drilling step, the insulating material is
at the outer rims of the first and second contact holes to be the
first and second insulating portions; and filling the conductive
material in the first and second contact holes.
27. A method for manufacturing a multi-layer stacked-type
piezoelectric device, the method comprising: manufacturing a
plurality piezoelectric units, each of the piezoelectric unit
comprising: a piezoelectric layer, having an upper surface and a
lower surface; a first conductive layer and a second conductive
layer, respectively located on the upper and lower surfaces of the
piezoelectric layer; a first contact hole and a second contact
hole, respectively penetrating two lateral sides of the first
conductive layer, the piezoelectric layer and the second conductive
layer; and a first insulating portion and a second insulating
portion, respectively formed in the first conductive layer and the
second conductive layer on the upper and lower surfaces of the
piezoelectric layer and at the outer rims of the first and second
contact holes; stacking the piezoelectric units, so that the first
or second insulating portion of each piezoelectric unit contacts
the first or second insulating portion of an adjacent piezoelectric
unit, wherein the first contact holes and the second contact holes
form a first channel and a second channel after the stacking step;
and filling a conductive material in the first channel and the
second channel, so that the first and second channels filled with
the conductive material respectively penetrate the piezoelectric
units.
28. The method according to claim 27, wherein the step of
manufacturing each of the piezoelectric unit further comprises:
forming a first insulation sidewall between the first contact hole
and the piezoelectric layer, the first insulation sidewall
connected to the first insulating portion; and forming a second
insulation sidewall between the second contact hole and the
piezoelectric layer, the second insulation sidewall connected to
the second insulating portion.
29. The method according to claim 27, wherein one piezoelectric
unit is rotated laterally 180.degree. and then stacked on another
piezoelectric unit.
30. A method for manufacturing a multi-layer stacked-type
piezoelectric unit, the method comprising: manufacturing a
plurality of first and second insulated piezoelectric bodies, each
of the first and second insulated piezoelectric bodies comprising:
a piezoelectric layer, having an upper surface and a lower surface;
a conductive layer, on the upper surface of the piezoelectric
layer; and a first insulating material and a second insulating
material, respectively formed at a left half and a right half of
the conductive layers of the first and second insulated
piezoelectric bodies; staggeredly stacking the first and second
insulated piezoelectric bodies, for forming a stacked-type
assembly; drilling the stacked-type assembly at the places
corresponding to the first and second insulating materials for
forming a first channel and a second channel, and the size of the
first and second channels being less than that of the first and
second insulating materials, so that a first insulating portion and
a second insulating portion are formed in the conductive layers of
the first and second insulated piezoelectric bodies respectively
after the drilling step; and filling a conductive material in the
first channel and the second channel, so that the first and second
channels with the conductive material respectively penetrate the
insulated piezoelectric bodies.
31. The method according to claim 30, wherein the first and second
insulating materials are aligned with the surfaces of the
conductive layers in which the insulating materials are formed.
32. The method according to claim 30, wherein the first and second
insulating materials are formed by high temperature coating.
33. The method according to claim 30 further comprising performing
hot-pressing sinter on the stacked-type assembly after the step of
forming the stacked-type assembly.
34. A method for manufacturing a multi-layer stacked-type
piezoelectric device, the method comprising: manufacturing a
plurality of first and second piezoelectric bodies, and each of the
piezoelectric bodies comprising: a piezoelectric layer, having an
upper surface and a lower; and a conductive layer, formed on the
upper surface of the piezoelectric layer, the conductive layers of
the first and second piezoelectric bodies respectively having a
first opening and a second opening, the first opening formed at the
left half of the piezoelectric layer correspondingly, the second
opening formed at the right half of the piezoelectric layer
correspondingly, staggeredly stacking the first and second
piezoelectric bodies for forming a stacked-type assembly; drilling
the stacked-type assembly corresponding to the first and second
openings forming a first channel and a second channel, the size of
the first and second channels being less than that of the first and
second openings; filling an insulating material in the first and
second channels and the first and second openings; drilling the
first and second channels again for removing the insulating
materials in the first and second channels, a first insulating
portion and a second insulating portion being respectively formed
on the conductive layers of the first and second piezoelectric
bodies after the drilling step; and filling a conductive material
in the first and second channels again.
35. The method according to claim 34 further comprising performing
hot-pressing sintering on the stacked-type assembly after the step
of forming the stacked-type assembly.
36. The method according to claim 34, wherein the conductive
material filled in the first and second channels is a conductive
adhesive.
Description
[0001] This application claims the benefit of Taiwan application
Serial No. 98123514, filed Jul. 10, 2009, the subject matter of
which is incorporated herein by reference.
BACKGROUND
[0002] 1. Technical Field
[0003] The disclosure relates in general to a stacked-type
piezoelectric device and a method for manufacturing the same, and
more particularly to a stacked-type piezoelectric device capable of
reducing damage and the volume and a method for manufacturing the
same.
[0004] 2. Description of the Related Art
[0005] Piezoelectric material has an asymmetric center in the
crystal phase, which results in uneven charge distribution. After
polarization treatment, the inputted voltage is converted into
mechanical displacement or deformation which generates electric
current. When the inputted voltage is alternative current, the
material vibrates correspondingly and generates vibration waves. On
the contrary, when the piezoelectric membrane is pressed which
generates deformation potential energy, the potential energy is
converted into electric energy at the moment of release.
[0006] Due to the special characteristics of the material, the
piezoelectric material is suitable for being applied to many
devices in people's daily lives, for energy saving and
environmental protection. For example, when the piezoelectric
device is applied to the lens of a compact electronic product, such
as the lens of a camera phone, a constant voltage can be applied to
the piezoelectric device under the lens for causing constant
expansion, which drives the lens to perform the focus adjustment.
When the piezoelectric device is applied to an ultrasonic
nebulizer, the piezoelectric ceramic membrane generates
high-frequency vibration waves, which break up water into extremely
fine mist droplets and sends the mist droplets to the air through
the high-frequency vibration principle of the piezoelectric effect.
Furthermore, through the piezoelectric effect, the deformed
piezoelectric material is able to generate electric current. For
example, the piezoelectric device is placed in the shock absorbent
material in the automobile engine. When the engine vibrates, the
piezoelectric device is deformed which generates electric current.
As a result, part of the energy is recycled to save energy. Other
examples include consumer products and industrial supplies, such as
the ink droplet control in the inkjet printer, ultrasonic medical
image, nondestructive testing for detecting the internal defects
within the structure . . . etc. However, most of the piezoelectric
devices are made of several sheets of stacked piezoelectric
materials for higher driving deformation or greater electric
current. The reasons include: (1) the deformation of the
piezoelectric materials is nonlinear, so it is easier to control
the deformation when the piezoelectric materials are stacked
together; and (2) less driving current is needed, which obtains
better frequency response.
[0007] Please refer to FIG. 1. FIG. 1 illustrates a stacked-type
piezoelectric actuator. Several vertically-stacked piezoelectric
layers 2 are electrically connected to each other and electrically
conducted through two lateral sides. When a low voltage is applied
for driving the device, those piezoelectric layers 2 are deformed.
As a result, the entire height of the piezo stack increases to
(L+.DELTA.L) from the original stacking height L.
[0008] Conventionally, when the stacked-type piezoelectric device
is in use, a conductive surrounding structure or a frame which
functions as a casing is required to fasten the piezoelectric
materials. Please refer to FIG. 2, which illustrates the structure
of a conventional piezoelectric actuator. The piezoelectric
actuator includes several vertically-stacked piezoelectric layers
2, an electrode layers 3 disposed between the piezoelectric layers
2, a frame 4 to fasten the piezoelectric layers 2 and a contact
layer 5 to conduct electricity to the electrode layers 3. The frame
4 is connected to the lateral sides of the piezoelectric layers 2
and electrically connected to an external connector 6 through a
copper wire 7. As shown in FIG. 2, an operating voltage is applied
to the connector 6, and the right half and the left half of the
frame 4 are connected to the positive and negative electrodes
respectively. As a result, the even-numbered and odd-numbered
layers of the electrode layers 3 which are counted from the top
carry positive and negative charge respectively. An electric field
is generated correspondingly in the center region M where electrode
layers 3 overlap. Accordingly, the piezoelectric layers 2
corresponding to the center region M deform and expand. The
expanding direction is indicated by the arrows. The portion of the
piezoelectric layers 2 corresponding to the edge region R expands
less because there is no electric field effect there. Lateral ends
of the piezoelectric layers 2 do not deform because being
restrained by the frame 4.
[0009] However, the conventional piezoelectric actuator has some
disadvantages when in practical use. The lateral ends of the
piezoelectric layers 2 are fastened by the frame 4. When the
central portion of the piezoelectric layers 2 deform, the total
height of the lateral sides remains the same. Therefore, tensile
stress exists at the boundary between the central portion and the
rim of the piezoelectric layers 2, which causes extremely uneven
stress distribution. When the deformation is greater, the tensile
stress becomes higher, which leads to fracture easily. Furthermore,
only part of the piezoelectric layers 2 which corresponds to the
center region M is deformed effectively. In the edge region R where
the electrodes do not overlap cannot effectively perform
piezoelectric effect. Moreover, the frame 4 used for fastening the
stacked piezoelectric layers 2 increases the entire volume of the
piezoelectric actuator, and the piezoelectric actuator becomes
heavier accordingly.
SUMMARY
[0010] According to the present disclosure, a stacked-type
piezoelectric device is provided. The device includes several
piezoelectric layers, several conductive layers, the first and
second contact holes and several insulating portions. The
piezoelectric layers are disposed between the conductive layers.
The first and second contact holes respectively penetrate the
piezoelectric layers and the conductive layers. A conductive
material is filled in the first and second contact holes. The
insulating portions are formed in the conductive layer
correspondingly. Two adjacent insulating portions are respectively
formed at the outer rims of the first and second contact holes, to
electrically isolate the conductive layer in which the insulating
portions are formed from the conductive material in the contact
hole.
[0011] According to the present disclosure, a multi-layer
stacked-type piezoelectric device is provided. The device includes
several piezoelectric units stacked together. Each piezoelectric
unit includes a piezoelectric layer, the first and second
conductive layers, the first and second contact holes, and the
first and second insulating portions. The piezoelectric layer has
an upper surface and a lower surface. The first and second
conductive layers are respectively formed on the upper and lower
surfaces of the piezoelectric layer. The first and second contact
holes respectively penetrate two lateral sides of the piezoelectric
layer, and each of the contact holes is filled with a conductive
material. The first and second insulating portions are respectively
formed in the first and second conductive layers on the upper and
lower surfaces of the piezoelectric layer. Also, the first and
second insulating portions are respectively formed at the outer
rims of the first and second contact holes, for electrically
isolating the conductive layer in which the insulating portions are
formed from the conductive material in the contact hole. In an
embodiment, the first and second contact holes respectively
penetrate two lateral sides of the first conductive layer, the
piezoelectric layer and the second conductive layer. Furthermore,
in the multi-layer stacked-type piezoelectric device, one of the
first and second insulating portions of each piezoelectric unit
corresponds to and contacts one of the first and second insulating
portions of an adjacent piezoelectric unit.
[0012] According to the present disclosure, a method for
manufacturing a multi-layer stacked-type piezoelectric device is
provided. First, several piezoelectric units are formed. Each
piezoelectric unit includes a piezoelectric layer having an upper
surface and a lower surface, the first and second conductive layers
respectively formed on the upper and lower surfaces of the
piezoelectric layer, the first and second contact holes
respectively penetrating two lateral sides of the first conductive
layer, the piezoelectric layer and the second conductive layer, and
the first and second insulating portions respectively formed in the
first and second conductive layers on the upper and lower surfaces
of the piezoelectric layer. Also, the first and second insulating
portions are respectively formed at the outer rims of the first and
second contact holes. Next, the piezoelectric units are stacked, so
that one of the first and second insulating portions of each
piezoelectric unit contacts one of the first and second insulating
portions of an adjacent piezoelectric unit. After stacked, the
first and second contact holes form the first and second channel.
Then, conductive material is filled in the first and second
channels respectively, so that the first and second channels with
the conductive material respectively penetrate the piezoelectric
units.
[0013] According to the present disclosure, a method for
manufacturing a multi-layer stacked-type piezoelectric device.
First, several first and second insulated piezoelectric bodies are
formed. Each of the first and second insulated piezoelectric bodies
includes a piezoelectric layer having an upper surface and a lower
surface, a conductive layer formed on the upper surface of the
piezoelectric layer, and the first and second insulating portions
respectively formed at a left half and a right half of the
conductive layers of the first and second insulated piezoelectric
bodies. Next, the first and second insulated piezoelectric bodies
are stacked staggeredly for forming a stacked-type assembly. Then,
the portions corresponding to the first and second insulating
materials of the stacked-type assembly are drilled, for forming the
first and second channels. The size of the first and second
channels is less than that of the first and second insulating
materials. As a result, the first and second insulating portions
are formed respectively in the conductive layers of the first and
second insulated piezoelectric bodies. Later, the first and second
channels are respectively filled with conductive material, so that
the first and second channels with the conductive material
respectively penetrate the insulated piezoelectric bodies.
[0014] According to the present disclosure, a method for
manufacturing a multi-layer stacked-type piezoelectric device.
First, several first and second piezoelectric bodies are formed.
Each of the first and second piezoelectric bodies includes a
piezoelectric layer having an upper surface and a lower surface,
and a conductive layer formed on the upper surface of the
piezoelectric layer. An first opening and an second opening are
formed respectively on each of the conductive layers of the first
and second piezoelectric bodies. The first openings are formed at
the left half of the piezoelectric layers, and the second openings
are formed at the right half of the piezoelectric layers. Next, the
first and second piezoelectric bodies are stacked staggeredly, for
forming a stacked-type assembly. Then, the stacked-type assembly
corresponding to the first and second openings is drilled to form
the first and second channels. The size of the first and second
channels is less than that of the first and second openings. Later,
the first and second channels and the first and second openings are
filled with an insulating material. Thereon, the first and second
channels are drilled again to remove the insulating material in the
first and second channels. After the drilling step, the first and
second insulating portions are formed in the conductive layers of
the first and second piezoelectric bodies. Subsequently, the first
and second channels are filled with conductive material.
[0015] The disclosure will become apparent from the following
detailed description of the exemplary but non-limiting embodiments.
The following description is made with reference to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 (PRIOR ART) illustrates a stacked-type piezoelectric
actuator;
[0017] FIG. 2 (PRIOR ART) illustrates the structure of a
conventional piezo-actuator;
[0018] FIG. 3A illustrates a stacked-type piezoelectric device
according to an exemplary embodiment of the present disclosure;
[0019] FIG. 3B illustrates another piezoelectric device according
to the exemplary embodiment of the present disclosure;
[0020] FIG. 4A.about.FIG. 4H show the flow of the method for
manufacturing a single piezoelectric unit structure according to
the first embodiment of the present disclosure;
[0021] FIG. 5A.about.FIG. 5B illustrate the flow of a method for
manufacturing a stacked-type piezoelectric device according to the
first embodiment of the present disclosure;
[0022] FIG. 6A.about.FIG. 6B are the top views of FIG.
5A.about.FIG. 5B respectively;
[0023] FIG. 7 illustrates the stacked-type piezoelectric device
according to the first embodiment of the present disclosure;
[0024] FIG. 8A.about.FIG. 8H illustrate the flow of a method for
manufacturing the stacked-type piezoelectric device according to
the second embodiment of the present disclosure;
[0025] FIG. 9A.about.FIG. 9G show the flow of a method for
manufacturing the stacked-type piezoelectric device according to
the third embodiment of the present disclosure;
[0026] FIG. 10 illustrates the stacked-type piezoelectric device
according to the third embodiment of the present disclosure;
and
[0027] FIG. 11A.about.FIG. 11H show the flow of the method for
manufacturing a stacked-type piezoelectric device according to the
fourth embodiment of the present disclosure.
DETAILED DESCRIPTION
[0028] A stacked-type piezoelectric device including at least two
piezoelectric layers is provided by the present disclosure. Each
piezoelectric layer has at least two contact holes. A conductive
layer is formed on at least one surface of each piezoelectric
layer. When stacked, several piezoelectric layers are staggered and
rotated in a plane. As a result, the contact holes of the
piezoelectric layers are aligned with each other precisely.
Conductive material is filled in the contact holes for forming
micro-actuators having positive and negative electrodes. In a
stacked-type piezoelectric device of the present disclosure, the
piezoelectric layers are drilled and then filled with the
conductive material for forming staggered positive and negative
electrodes which penetrate the piezoelectric material. There is no
need to use the frame which is used in the conventional
piezoelectric actuator to fasten the piezoelectric material. The
actuator deforms and expands evenly, which results in less damage
and fractures due to excessive tensile stress. The size is reduced
significantly, and the appearance is simplified. Therefore, a
small-size actuator can be formed.
[0029] Four embodiments are provided for demonstrating the
structure of stacked-type piezoelectric device of the present
disclosure and method for manufacturing the same. However, the
embodiments disclosed herein are used for illustrative purpose, but
not for limiting the scope of the disclosure. Also, it is known for
people skill in the art that the structure presented in the
embodiments and drawings could be slightly modified under the
spirit of the disclosure. The specification and the drawings are to
be regard as an illustrative sense rather than a restrictive sense.
Additionally, the drawings used for illustrating the embodiments
and applications of the present disclosure only show the major
characteristic parts in order to avoid obscuring the present
disclosure.
[0030] Please refer to FIG. 3A. FIG. 3A illustrates a stacked-type
piezoelectric device according to an embodiment of the present
disclosure. The stacked-type piezoelectric device 10 includes
several piezoelectric layers 11a.about.11d, several conductive
layers 13a.about.13e, the first contact hole 15a, the second
contact hole 15b and several insulating portions 16a.about.16e. The
piezoelectric layers 11a.about.11d are disposed between the
conductive layers 13a.about.13e. The first contact hole 15a and the
second contact hole 15b at least penetrate the piezoelectric layers
11a.about.11d. For example, the first contact hole 15a and the
second contact hole 15b respectively penetrate two lateral sides of
the piezoelectric layers 11a.about.11d and the conductive layers
13a.about.13e. Each of the first contact hole 15a and the second
contact hole 15b is filled with conductive material. In an
embodiment, the first contact hole 15a and the second contact hole
15b respectively penetrate two lateral sides of the piezoelectric
layers 11a.about.11d and the conductive layers 13a.about.13e
vertically. However, the present disclosure does not limit the way
that the contact holes penetrate the layers.
[0031] The insulating portions 16a.about.16e are respectively
formed in the conductive layers 13a.about.13e correspondingly. Two
adjacent insulating portions are formed at the outer rims of the
first contact hole 15a and the second contact hole 15b
respectively, to electrically isolate the conductive layer in which
the insulating portion is formed from the conductive material in
the contact hole. For example, the insulating portion 16a is formed
in the conductive layer 13a, and the insulating portion 16b is
formed in the conductive layer 13b. The two adjacent insulating
portions 16a and 16b are at the outer rims of the first contact
hole 15a and the second contact hole 15b respectively. As a result,
the conductive layers 13a and 13b are electrically isolated from
the conductive materials in the first contact hole 15a and the
second contact hole 15b due to the existence of the insulating
portions 16a and 16b. Similarly, the conductive layers 13c and 13e
are electrically isolated from the conductive material in the first
contact hole 15a due to the existence of the insulating portions
16c and 16e. The conductive layer 13d is electrically isolated from
the conductive material in the second contact hole 15b due to the
existence of the insulating portion 16d.
[0032] Furthermore, although different patterns are used in FIG. 3A
for representing the locations of the first contact hole 15a, the
second contact hole 15b and the conductive layers 13a.about.13c,
the conductive material in the first contact hole 15a and the
second contact hole 15b can be the same as or different from the
conductive material of the conductive layers 13a.about.13c
practically. The present disclosure is not limited thereto.
[0033] When the stacked-type piezoelectric device 10 in FIG. 3A is
in use, the first contact hole 15a and the second contact hole 15b
can be electrically connected with the negative and positive
electrodes of a source respectively. When an operating voltage is
applied to the stacked-type piezoelectric device 10, the first
contact hole 15a and the conductive layers 13d and 13b carry
negative charge, and the second contact hole 15b and the conductive
layers 13e, 13c and 13a carry positive charge. As a result, the
piezoelectric layers 11a.about.11d between the conductive layers
13a.about.13e deform and expand along the directions indicated by
the arrows.
[0034] The stacked-type piezoelectric device 10 does not have the
frame which is used in the conventional piezoelectric actuator for
fastening the piezoelectric layers. Therefore, the piezoelectric
layers 11a.about.11d are able to expand evenly in a plane with less
damage due to excessive tensile stress. Moreover, the first contact
hole 15a and the second contact hole 15b only occupy a small area
of the piezoelectric layers 11a.about.11d. As a result, for the
piezoelectric layers of the same size, the stacked-type
piezoelectric device 10 of the present disclosure has larger ratio
of the effect area to perform piezoelectric effect than the
conventional piezoelectric actuator. Besides, as to the appearance
of both devices, the volume of the stacked-type piezoelectric
device 10 of the present disclosure only includes the stacked
piezoelectric layers 11a.about.11d and the conductive layers
13a.about.13e. Therefore, compared to the conventional
piezoelectric actuator which needs a fastening frame, the device of
the present disclosure has much less volume.
[0035] Please refer to FIG. 3B. FIG. 3B illustrates a piezoelectric
device according to another exemplary embodiment of the present
disclosure. The identical components shown in FIG. 3B and FIG. 3A
are denoted as the same reference numbers. Compared to the device
in FIG. 3A, the device in FIG. 3B has similar structure except that
the device in FIG. 3B further includes several insulation sidewalls
17b.about.17e which are connected to the insulating portions
16b.about.16e perpendicularly. Also, the insulation sidewalls
17b.about.17e are located between the piezoelectric layers and the
first and second contact holes 15a and 15b, to electrically isolate
the piezoelectric layers from the conductive material in the
contact holes 15a and 15b. When an operating voltage is applied to
the stacked-type piezoelectric device 20, the insulation sidewalls
17b.about.17e prevent the piezoelectric layers 11a.about.11d from
lateral deformation and expansion. As a result, the piezoelectric
layers 11a.about.11d only expand along the direction indicated by
the arrows.
[0036] For example, the insulation sidewall 17b connected to the
insulating portion 16b is located between the piezoelectric layer
11a and the second contact hole 15b, to electrically isolate the
piezoelectric layer 11a from the conductive material in the second
contact hole 15b. Similarly, the insulation sidewall 17d
electrically isolates the piezoelectric layer 11c from the
conductive material in the second contact hole 15b. The insulation
sidewall 17c electrically isolates the piezoelectric layer 11b from
the conductive material in the first contact hole 15a. The
insulation sidewall 17e electrically isolates the piezoelectric
layer 11d from the conductive material in the first contact hole
15a.
[0037] Although the stacked-type piezoelectric devices in FIG. 3B
and FIG. 3A include four piezoelectric layers 11a.about.11d as
examples, the present disclosure does not limit the number of the
piezoelectric layers. The present disclosure encompasses the
stacked-type piezoelectric devices having at least two
piezoelectric layers. In other words, the stacked-type
piezoelectric device provided by the present disclosure includes n
piezoelectric layers and (n+1) conductive layers. n is an positive
integer not less than 2. The piezoelectric layers are staggered
between the conductive layers. The insulating portions of the
odd-numbered conductive are corresponding to the outer rims of the
first contact hole. The insulating portions of the even-numbered
conductive layers are corresponding to the outer rims of the second
contact hole.
[0038] Several exemplary embodiments are provided by the present
disclosure according to the above-described piezoelectric device
for illustrating at least four methods for manufacturing the
stacked-type piezoelectric device. However, the detailed steps of
the manufacturing methods and the structures revealed in the
embodiments are used as examples and not to limit the present
disclosure. Moreover, the drawings of the embodiments only show the
components related to the present disclosure. Unnecessary
components are neglected for clarity.
First Embodiment
[0039] In the first embodiment, several piezoelectric unit
structures are manufactured first. Conductive layers are formed on
the upper and lower surfaces of the piezoelectric layers in each
piezoelectric unit structure, and the contact holes penetrate the
structure vertically. Then, the piezoelectric unit structures are
stacked together, and the conductive material is filled in the
contact holes. Insulation sidewalls and insulating portions are
formed in each piezoelectric unit structure as shown in FIG.
3B.
[0040] Please refer to FIG. 4A.about.4H, which show the flow of the
method for manufacturing a single piezoelectric unit structure
according to the first embodiment of the present disclosure.
[0041] As shown in FIG. 4A, a piezoelectric layer 31 is provided
first, and the piezoelectric layer 31 has an upper surface 31a and
a lower surface 31b. Next, the first penetrating hole 311a and the
second penetrating hole 311b are formed on both sides of the
piezoelectric layer 31, and the insulating materials 32a and 32b
are filled in the first penetrating hole 311a and the second
penetrating hole 311b respectively, as shown in FIG. 4B. The first
penetrating hole 311a and the second penetrating hole 311b
vertically penetrate the piezoelectric layer 31. After the
insulating materials 32a and 32b are filled in the first
penetrating hole 311a and the second penetrating hole 311b, the
surfaces of the insulating materials 32a and 32b are aligned with
the upper and lower surfaces 31a and 31b of the piezoelectric layer
31 respectively. The insulating materials 32a and 32b may be
non-conductive adhesive, such as epoxy or other non-conductive
materials. The shape of the first penetrating hole 311a and the
second penetrating hole 311b has no limitation and can be a circle,
ellipse, rectangle or any other shape. In the present embodiment,
the first penetrating hole 311a and the second penetrating hole
311b are circular as an example and has the same penetrating
diameter L.sub.1.
[0042] Then, as shown in FIG. 4C, the first conductive layer 33 is
formed on the upper surface 31a of the piezoelectric layer 31.
Subsequently, as shown in FIG. 4D, the piezoelectric layer 31 is
turned upside down, and the second conductive layer 34 is formed on
the lower surface 31b of the piezoelectric layer 31. The first and
second conductive layers 33 and 34 cover the insulating materials
32a and 32b respectively.
[0043] Thereon, as shown in FIG. 4E, the first contact hole 35a and
the second contact hole 35b are formed corresponding to the first
penetrating hole 311a and the second penetrating hole 311b
respectively by drilling. The diameter L.sub.2 of the drilled first
contact hole 35a and the second contact hole 35b is less than the
diameter L.sub.1 of the first penetrating hole 311a and the second
penetrating hole 311b. The first insulating sidewall 37a and the
second insulating sidewall 37b are formed accordingly. The first
contact hole 35a and 35b vertically penetrate the second conductive
layer 34, the piezoelectric layer 31 and the first conductive layer
33 respectively.
[0044] Later, a portion of the conductive layers on the upper and
lower sides of the piezoelectric layer 31 corresponding to the
outer rims of the first contact hole 35a and the second contact
hole 35b is removed. As shown in FIG. 4F, a portion of the second
conductive layer 34 corresponding to the outer rim of the first
contact hole 35a is removed for forming an opening 341. A portion
of the first conductive layer 33 corresponding to the outer rim of
the second contact hole 35b is removed for forming an opening 331.
The diameter L.sub.3 of the openings 331 and 341 is larger than the
diameter L.sub.2 of the first contact hole 35a and the second
contact hole 35b and the diameter L.sub.1 of the first penetrating
hole 311a and the second penetrating hole 311b. Also, there is no
limitation on the shape of the openings 331 and 341. The openings
331 and 341 can be circular, elliptical, rectangular or any other
shape.
[0045] Then, as shown in FIG. 4G, the insulating materials 38a and
38b are filled in the first contact hole 35a and the second contact
hole 35b. Also, the insulating material 38a and 38b are fully
filled in the openings 331 and 341. The surfaces of the insulating
materials 38a and 38b are aligned with the upper and lower surfaces
of the first and second conductive layers 33 and 34
respectively.
[0046] Next, as shown in FIG. 4H, drilling is performed on the
first contact hole 35a and the second contact hole 35b for leaving
the insulating material at the outer rims of the first contact hole
35a and the second contact hole 35b to form the first insulating
portion 39a and the second insulating portion 39b. After drilling,
the first insulation sidewall 37a is located between the first
contact hole 35a and the piezoelectric layer 31 and connected to
the first insulating portion 39a. The second insulation sidewall
37b is located between the second contact hole 35b and the
piezoelectric layer 31 and connected to the second insulating
portion 39b. Furthermore, one end of the first insulation side wall
37a is aligned with the lower surface 31a of the piezoelectric
layer 31, and one end of the second insulation side wall 37b is
aligned with the upper surface 31b of the piezoelectric layer 31.
As to the selection of the material, the insulating materials 38a
and 38b of the first and second insulating portions 39a and 39b can
be the same as or different from the insulating materials 32a and
32b of the first and second insulation sidewalls 37a and 37b, which
depends on the practical conditions. The present disclosure is not
limited thereto.
[0047] Following the above-described steps in FIG. 4A.about.4H, a
piezoelectric unit structure 40 can be manufactured
accordingly.
[0048] Next, several piezoelectric unit structures 40 in FIG. 4H
are stacked vertically. The conductive materials are filled in the
contact holes to form a multi-layer stacked-type piezoelectric
device. Thus, the deformation driven by the piezoelectric device
when in use is increased, or greater electric current is generated.
When stacked in a staggered manner, the piezoelectric unit
structure 40 is laterally rotated 180.degree. and then stacked on
another piezoelectric unit structure 40.
[0049] FIG. 5A.about.FIG. 5B illustrate the flow of a method for
manufacturing a stacked-type piezoelectric device according to the
first embodiment of the present disclosure. FIG. 6A.about.FIG. 6B
are the top views of FIG. 5A.about.FIG. 5B respectively. Please
refer to FIG. 5A.about.FIG. 5B and FIG. 6A.about.FIG. 6B at the
same time. Five piezoelectric unit structures in FIG. 4G are
stacked as an example for illustrating the present embodiment.
[0050] As shown in FIG. 5A and FIG. 6A, several piezoelectric unit
structures 401.about.405 are stacked vertically. When stacked, one
piezoelectric unit structure is laterally rotated 180.degree. and
then stacked on another piezoelectric unit structure. For example,
after laterally rotated 180.degree., the first contact hole 35a of
the piezoelectric unit structure 402 is aligned with the second
contact hole 35b of the lower adjacent piezoelectric unit structure
401. Similarly, the first contact hole 35a of the piezoelectric
unit structure 404 is aligned with the second contact hole 35b of
the lower adjacent piezoelectric unit structure 403. Also, as shown
in FIG. 5A, the first insulating portion 39a of the stacked
piezoelectric unit structure 403 contacts the second insulating
portion 39b of the upper adjacent piezoelectric unit structure 404.
The first contact holes 35a and the second contact holes 35b of the
stacked piezoelectric unit structures 401.about.405 form the first
channel R.sub.H and the second channel L.sub.H.
[0051] Later, as shown in FIG. 5B and FIG. 6B, the conductive
materials 501a and 501b are filled in the first channel R.sub.H and
the second channel L.sub.H respectively for forming a stacked-type
piezoelectric device 50. The first channel R.sub.H and the second
channel L.sub.H vertically penetrate the piezoelectric unit
structures 401.about.405. The conductive materials 501a and 501b
may be conductive adhesive (such as silver paste) or tin/lead
solder for example.
[0052] FIG. 7 illustrates the stacked-type piezoelectric device
according to the first embodiment of the present disclosure. When
the stacked-type piezoelectric device 50 in FIG. 5B is in practical
use, the conductive material 501a in the first channel R.sub.H and
the conductive material 501b in the second channel L.sub.H are
electrically connected to the negative and positive electrodes of
an external source respectively. When an operating voltage is
applied to the stacked-type piezoelectric device 50, the
piezoelectric layers between the electrode layers deform and expand
along the directions indicated by the arrows. Anyone who has
ordinary skill in the field of the present disclosure can
understand that when in practical use, a constant voltage can be
applied to the stacked-type piezoelectric device 50 for generating
specific deformation. Or, an alternative current can be applied to
the stacked-type piezoelectric device 50 for generating
high-frequency vibration. Or, the stacked-type piezoelectric device
50 is deformed to generate electric current. Modification can be
made depending on the practical conditions.
[0053] The piezoelectric unit structure in FIG. 4H manufactured
following the steps in FIG. 4A.about.FIG. 4H mainly includes the
piezoelectric layer 31, the first and second conductive layers 33
and 34 respectively formed above and under the piezoelectric layer
31, the first and second contact holes 35a and 35b vertically
penetrating the piezoelectric layer 31, the first conductive layer
33 and the second conductive layer 34, the first and second
insulating portions 39a and 39b respectively formed in the first
and second conductive layers 33 and 34 respectively surrounding the
outer rims of the first and second contact holes 35a and 35b, and
the first and second insulation sidewalls 37a and 37b respectively
connected to the first and second insulating portions 39a and 39b.
What is worth mentioning is that when the conductive materials are
directly filled in the first and second contact holes 35a and 35b,
a piezoelectric device with a single-layer piezoelectric layer can
be formed accordingly.
[0054] A stacked-type piezoelectric device 50 can be formed by
stacking the piezoelectric unit structures as shown in FIG. 4H
following the steps in FIG. 5A.about.FIG. 5B. Piezoelectric effect
occurs in the piezoelectric layers 31 under the action of the
electric field due to the locations of the first and second
insulating portions 39a and 39b and the first and second insulation
sidewalls 37a and 37b. FIG. 7 shows the polarity of each
piezoelectric layer and the first and second conductive layers of
the device 50 when the conductive materials 501a and 501b
respectively in the first channel R.sub.H and the second channel
L.sub.H are electrically connected to the negative and positive
electrodes of an external source. The insulating portions are used
for electrically isolating the conductive layers from the
conductive materials in some of the adjacent contact holes. The
insulating sidewalls are used for electrically isolating the
piezoelectric layers from the conductive materials in the adjacent
contact holes.
[0055] What is worth mentioning is that although the conductive
layers are formed on the upper and lower surfaces of each
piezoelectric unit structure in the stacked-type piezoelectric
device 50, the two adjacent conductive layers between the stacked
piezoelectric layers in FIG. 7 can still be considered to be a
single layer, compared to the structure in FIG. 3B. Therefore, the
present disclosure encompasses the stacked-type piezoelectric
device 50 according to the first embodiment of the present
disclosure.
Second Embodiment
[0056] In the second embodiment, several piezoelectric unit
structures with conductive layers on both the upper and lower
surfaces and the contact holes penetrating the structure are formed
first, which is the same as the first embodiment. Next, the
piezoelectric unit structures are stacked, and the conductive
materials are filled in the contact holes. The difference between
the second and first embodiments is that only the insulating
portion but no insulation sidewall is formed in the piezoelectric
unit structure according to the second embodiment. The stacked-type
piezoelectric device according to the second embodiment is
encompassed by the technical field in FIG. 3A of the present
disclosure.
[0057] Please refer to FIG. 8A.about.FIG. 8H, which illustrate the
flow of a method for manufacturing the stacked-type piezoelectric
device according to the second embodiment of the present
disclosure.
[0058] First, as shown in FIG. 8A, a piezoelectric layer 61 is
provided. The piezoelectric layer 61 has an upper surface 61a and a
lower surface 61b. Next, as shown in FIG. 8B, the first conductive
layer 63 and the second conductive layer 64 are respectively formed
on the upper and lower surfaces 61a and 61b of the piezoelectric
layer 61.
[0059] Then, as shown in FIG. 8C, the first penetrating hole 611a
and the second penetrating hole 611b are respectively formed on
both sides of the piezoelectric layer 61. The first penetrating
hole 611a and the second penetrating hole 611b vertically penetrate
the second conductive layer 64, the piezoelectric layer 61 and the
first conductive layer 63. There is no limitation on the shape of
the penetrating holes 611a and 611b. In the present embodiment, the
first penetrating hole 611a and the second penetrating hole 611b
are circular and have the same penetrating diameter L.sub.4 as an
example.
[0060] Subsequently, as shown in FIG. 8D, a portion of the
conductive layers above and under the piezoelectric layer 61
corresponding to the first and second penetrating holes 611a and
611b is removed. For example, a portion of the second conductive
layer 64 corresponding to the first penetrating hole 611a is
removed to form an opening 641. A portion of the first conductive
layer 63 corresponding to the second penetrating hole 611b is
removed to form an opening 631. The diameter L.sub.5 of the
openings 631 and 641 is larger than the diameter L.sub.4 of the
first and second penetrating holes 611a and 611b. Moreover, there
is no limitation on the shape of the openings 631 and 641. The
openings 631 and 641 can be circular, elliptical, rectangular or
any other shape.
[0061] Later, as shown in FIG. 8E, the insulating materials 62a and
62b are filled in the first and second penetrating holes 611a and
611b. The insulating materials 62a and 62b are also fully filled in
the openings 631 and 641. The exposed surfaces of the insulating
materials 62a and 62b are aligned with the upper and lower surfaces
of the first and second conductive layers 63 and 64 after the
filling step. The insulating materials 62a and 62b are
non-conductive adhesive for example, such as epoxy or other
non-conductive materials.
[0062] Thereon, as shown in FIG. 8F, the places corresponding to
the first and second penetrating holes 611a and 611b are drilled to
form the first and second contact holes 65a and 65b respectively.
The diameter L.sub.4 of the first and second contact holes 65a and
65b is the same as the diameter L.sub.4 of the first and second
penetrating holes 611a and 611b. The first and second contact holes
65a and 65b vertically penetrate the second conductive layer 64,
the piezoelectric layer 61 and the first conductive layer 63
respectively. After the drilling step, the insulating materials are
left at the places corresponding to the outer rims of the first and
second contact holes 65a and 65b to form the first and second
insulating portions 66a and 66b. The first and second insulting
portions 66a and 66b are respectively on the upper and lower sides
of the piezoelectric layer 61.
[0063] A piezoelectric unit structure is formed following the steps
in FIG. 8A.about.FIG. 8F.
[0064] Then, as shown in FIG. 8G, several piezoelectric unit
structures 701.about.705 in FIG. 8F are stacked vertically. When
stacked, the piezoelectric unit structure is laterally rotate
180.degree. and then stacked on another piezoelectric unit
structure. For example, after laterally rotated 180.degree., the
first contact hole 65a of the piezoelectric unit structure 702 is
aligned with the second contact hole 65b of the lower adjacent
piezoelectric unit structure 701. Similarly, the first contact hole
65a of the piezoelectric unit structure 704 is aligned with the
second contact hole 65b of the lower adjacent piezoelectric unit
structure 703. Also, the first insulating portion 66a of the
stacked piezoelectric unit structure contacts the second insulating
portion 66b of the adjacent piezoelectric unit structure. For
example, the first insulating portion 66a of the piezoelectric unit
structure 703 contacts the second insulating portion 66b of the
upper adjacent piezoelectric unit structure 704. The first contact
holes 65a and the second contact holes 65b of the stacked
piezoelectric unit structures 701.about.705 form the first channel
R.sub.H and the second channel L.sub.H.
[0065] Later, as shown in FIG. 8H, the conductive materials 72a and
72b are filled in the first channel R.sub.H and the second channel
L.sub.H respectively for forming a stacked-type piezoelectric
device 70. The first channel R.sub.H and the second channel L.sub.H
with the conductive materials 72a and 72b vertically penetrate the
piezoelectric unit structures 701.about.705 respectively. The
conductive materials 72a and 72b may be conductive adhesive (such
as silver paste) or tin/lead solder.
[0066] What is worth mentioning is that when the conductive
materials are directly filled in the first and second contact holes
65a and 65b of the piezoelectric unit structures in FIG. 8F, a
single-layer piezoelectric device is formed accordingly. When in
use, the stacked-type piezoelectric device 70 in FIG. 8H has larger
deformation or generates greater electric current. Although the
second embodiment does not have the first and second insulation
sidewalls 37a and 37b of the first embodiment (ex. FIG. 4H), each
insulating portion is used for isolating the conductive layer from
the conductive material in one of the adjacent contact hole.
Therefore, effective deformation occurs along the vertical
direction under the action of electric field.
[0067] What is worth mentioning is that although the conductive
layers are formed on the upper and lower surfaces of each
piezoelectric unit structure in the stacked-type piezoelectric
device 70 in FIG. 8H, the two adjacent conductive layers between
the stacked piezoelectric layers in FIG. 8H can be considered to be
a single layer. Therefore, the second embodiment is encompassed by
the field of the technical features in FIG. 3A of the present
disclosure.
Third Embodiment
[0068] In the first and second embodiments, the conductive layers
are formed on both the upper and lower surfaces of each
piezoelectric layer. However, in the third embodiment, the
conductive layer is formed on only one surface of the piezoelectric
layer. Next, the insulating portion is formed on the conductive
layer. Then, stacking, drilling and conductive material filling
steps are performed for conducting electricity in order to form the
stacked-type piezoelectric device.
[0069] Please refer to FIG. 9A.about.FIG. 9G, which show the flow
of a method for manufacturing the stacked-type piezoelectric device
according to the third embodiment of the present disclosure. As
shown in FIG. 9A, a piezoelectric layer 81 is provided first. The
piezoelectric layer 81 has an upper surface 81a and a lower surface
81b. Then, a conductive layer 82 (to be the electrode layer) is
formed on one of the surfaces of the piezoelectric layer 81, such
as the upper surface 81a in FIG. 9B, and an opening 821 is formed
on the conductive layer 82 adjacent to one side, such as the left
side (or the right side). The opening 821 exposes the upper surface
81a of the piezoelectric layer 81 under the opening 821. There is
no limitation on the shape of the opening 821. The opening 821 can
be circular, elliptical, rectangular, or any other shape. In the
present embodiment, the opening is circular as an example, and the
diameter of the opening 821 is L.sub.6.
[0070] Next, as shown in FIG. 9C, the insulating material 83 is
formed in the opening 821. After the insulating material 83 is
filled in the opening 821, the surface of the insulating material
83 is aligned with the surface of the conductive layer 82. The
insulating material 83 is for example a non-conductive adhesive,
such as epoxy or another non-conductive material. When in practical
use, the insulating material 83 can be filled in the opening 821 by
many different methods, such as high temperature coating (for
example, the temperature is greater than 700.degree. C.). However,
the present disclosure is not limited thereto. An insulating
piezoelectric body P is formed by following the steps shown in FIG.
9A.about.FIG. 9C.
[0071] Then, as shown in FIG. 9D, several piezoelectric bodies P as
shown in FIG. 9C are stacked vertically. When stacked in a
staggered manner, one insulating piezoelectric body P is laterally
rotate 180.degree. and then stacked on another piezoelectric body P
for forming a stacked-type assembly. Take FIG. 9D for example. The
insulating material 83 of two adjacent insulating piezoelectric
bodies, such as P1 and P2, are respectively formed on the right
half and left half of the conductive layers 82 respectively. Along
the vertical direction, the location of the insulating material 83
of the insulating piezoelectric body P4 is corresponding to the
location of the insulating material 83 of the insulating
piezoelectric body P2. The location of the insulating material 83
of the piezoelectric body P3 is corresponding to the location of
the insulating material 83 of the piezoelectric body P1.
[0072] Then, as shown in FIG. 9E, hot-pressing sintering is
performed on the stacked insulating piezoelectric bodies
P1.about.P4 for forming a stacked-type assembly S.sub.1.
[0073] Thereon, portions of the stacked-type assembly S.sub.1 which
correspond to the insulating material 83 is drilled to form the
first channel R.sub.H and the second channel L.sub.H, as shown in
FIG. 9F. There is no limitation on the shape of the channel formed
by drilling. In the present embodiment, the channel is circular,
and the diameter is L.sub.7 as an example. Therefore, after the
drilling step, the insulating portions 85 are formed on the
conductive layers 82 of the insulating piezoelectric bodies
P1.about.P4.
[0074] Later, as shown in FIG. 9G, the conductive materials 86a and
86b are filled in the first channel R.sub.H and the second channel
L.sub.H, for forming a stacked-type piezoelectric device. The first
channel R.sub.H and the second channel L.sub.H with the conductive
materials 86a and 86b respectively penetrate the insulated
piezoelectric bodies P1.about.P4. The conductive materials 86a and
86b are for example elastic conductive materials (such as
conductive adhesive or silver paste) or tin/lead solder. The step
of filling the conductive materials 86a and 86b can be performed by
chemical-plating, electroplating, photolithography process or any
other practical method. The present disclosure is not limited
thereto.
[0075] FIG. 10 illustrates the stacked-type piezoelectric device
according to the third embodiment of the present disclosure. When
the stacked-type piezoelectric device manufactured by the steps in
FIG. 9A.about.FIG. 9G is in practical use, the conductive material
86a in the first channel R.sub.H and the conductive material 86b in
the second channel L.sub.H are respectively connected to the
positive and negative electrodes of an external power source. The
insulating portion 85 is used for isolating the conductive layers
from the conductive material (86a or 86b) in one of the adjacent
channel. FIG. 10 shows the polarity of each conductive layer. When
a constant voltage is applied to the stacked-type piezoelectric
device in FIG. 10 in practical use, the piezoelectric layers 81
between the conductive layers 82 deform and expand along the
directions indicated by the arrows.
[0076] Furthermore, the stacked-type piezoelectric device
manufactured according to the third embodiment of the present
disclosure is encompassed by the field of the technical features in
FIG. 3A of the present disclosure.
Fourth Embodiment
[0077] The method of the fourth embodiment is slightly different
from that of the third embodiment, but the structures of the
stacked-type piezoelectric devices are the same which are
encompassed by the field of the technical features in FIG. 3A of
the present disclosure. In the fourth embodiment, the stacked
piezoelectric bodies are drilled, filled with the insulating
material, drilled again and filled with the conductive material for
conducting electricity in order to form a stacked-type
piezoelectric device. Furthermore, the components of the fourth
embodiment which are the same as those of the third embodiment use
the same reference numbers for easier illustration.
[0078] Please refer to FIG. 11A.about.FIG. 11H, which show the flow
of the method for manufacturing a stacked-type piezoelectric device
according to the fourth embodiment of the present disclosure.
First, as shown in FIG. 11A, a piezoelectric layer 81 is provided.
The piezoelectric layer 81 has an upper surface 81a and a lower
surface 81b. Next, a conductive layer 82 (to be the electrode
layer) is formed on one surface of the piezoelectric layer 81, such
as the upper surface 81a in FIG. 11B, and an opening 821 is formed
on the conductive layer 82 adjacent to one side, such as the left
side (or the right side), of the piezoelectric layer 81. The
opening 821 can be circular, elliptical, rectangular, or any other
shape. In the present embodiment, the opening is circular as an
example, and the diameter of the opening 821 is L.sub.6.
[0079] Next, as shown in FIG. 11C, several piezoelectric bodies Q
as shown in FIG. 11B are stacked vertically. When stacked in a
staggered manner, one insulating piezoelectric body Q is laterally
rotate 180.degree. and then stacked on another piezoelectric body Q
for forming a stacked-type assembly. Take FIG. 11C for example. The
openings 821 of two adjacent piezoelectric bodies, such as Q1 and
Q2, are respectively formed on the right half and left half of the
conductive layer 82. Along the vertical direction, the location of
the opening 821 of the piezoelectric body Q4 is corresponding to
the location of the opening 821 of the piezoelectric body Q2. The
location of the opening 821 of the piezoelectric body Q3 is
corresponding to the location of the opening 821 of the
piezoelectric body Q1.
[0080] Subsequently, as shown in FIG. 11D, hot-pressing sintering
is performed on the stacked piezoelectric bodies Q1.about.Q4 for
forming a stacked-type assembly S.sub.2.
[0081] Thereon, a portion of the stacked-type assembly S.sub.2
which corresponds to the opening 821 is drilled to form the first
channel R.sub.H and the second channel L.sub.H, as shown in FIG.
11E. There is no limitation on the shape of the channel formed by
drilling. In the present embodiment, the channel is circular, and
the diameter is L.sub.8 as an example. The diameter L.sub.8 of the
channel is less than the diameter L.sub.6 of the opening 821.
[0082] Later, as shown in FIG. 11F, the insulating materials 84a
and 84b are filled in the first channel R.sub.H, the second channel
L.sub.H and the opening 821. After the filling step, the surfaces
of the insulating materials 84a and 84b are aligned with the
surface of the conductive layer 82. For example, the insulating
materials 84a and 84b may be non-conductive adhesive, such as epoxy
or another non-conductive material.
[0083] Next, as shown in FIG. 11G, the first channel R.sub.H and
the second channel L.sub.H are drilled again for removing the
insulating materials in the first channel R.sub.H and the second
channel L.sub.H. The insulating portions 85 are formed in the
conductive layers 82 of the piezoelectric bodies Q1.about.Q4. The
diameter of the drilled holes is L.sub.8.
[0084] Later, as shown in FIG. 11H, the conductive materials 86a
and 86b are respectively filled in the first channel R.sub.H and
the second channel L.sub.H, for forming a stacked-type
piezoelectric device. The first channel R.sub.H and the second
channel L.sub.H with the conductive materials 86a and 86b
vertically penetrate the piezoelectric bodies Q1.about.Q4
respectively. The conductive materials 86a and 86b are for example
elastic conductive materials (such as conductive adhesive or silver
paste) or tin/lead solder. The step of filling the conductive
materials 86a and 86b can be performed by chemical-plating,
electroplating, photolithography process or any other practical
method. The present disclosure is not limited thereto.
[0085] When the stacked-type piezoelectric device in FIG. 11H is in
practical use, the conductive materials 86a filled in the first
channel R.sub.H and the conductive material 86b filled in the
second channel L.sub.H are respectively connected to the positive
and negative electrodes of an external power source. The insulating
portions 85 are used for isolating the conductive layers from the
conductive material (86a or 86b) in the adjacent channel. When a
constant voltage is applied to the stacked-type piezoelectric
device in practical use, the piezoelectric layers 81 between the
conductive layers 82 deform and expand along the directions
indicated by the arrows.
[0086] In the stacked-type piezoelectric devices according to the
first to fourth embodiments of the present disclosure, the
piezoelectric material is drilled and then filled with the
conductive material to form the piezoelectric device with staggered
positive and negative electrodes. Whether the device according to
the embodiments has the structure in FIG. 3A or FIG. 3B, there is
no need to use the frame which is used conventionally for fastening
the piezo-actuator. As a result, the planar driving material
expands and deforms evenly, and the piezoelectric layer does not
crack easily due to excessive tensile stress. Furthermore, the size
of the device is reduced greatly, and the appearance is simplified.
Therefore, a compact actuator can be manufactured accordingly.
[0087] The disclosure is directed to a stacked-type piezoelectric
device and a manufacturing method thereof. When in practical use,
the manufactured piezoelectric materials of the piezoelectric
device deforms evenly in a plane, which reduces the possibility of
damage and fracture. Also, the appearance of the device is
simplified, and the volume is decreased greatly.
[0088] While the disclosure has been described by way of example
and in terms of a exemplary embodiment, it is to be understood that
the disclosure is not limited thereto. On the contrary, it is
intended to cover various modifications and similar arrangements
and procedures, and the scope of the appended claims therefore
should be accorded the broadest interpretation so as to encompass
all such modifications and similar arrangements and procedures.
* * * * *