U.S. patent application number 11/240796 was filed with the patent office on 2006-10-05 for structure of a structure release and a method for manufacturing the same.
Invention is credited to Mark W. Miles.
Application Number | 20060220160 11/240796 |
Document ID | / |
Family ID | 34216394 |
Filed Date | 2006-10-05 |
United States Patent
Application |
20060220160 |
Kind Code |
A1 |
Miles; Mark W. |
October 5, 2006 |
Structure of a structure release and a method for manufacturing the
same
Abstract
A structure of a structure release and a manufacturing method
are provided. The structure and manufacturing method are adapted
for an interference display cell. The structure of the interference
display cell includes a first electrode, a second electrode and at
least one supporter. The second electrode has at least one hole and
is arranged about parallel with the first electrode. The supporter
is located between the first electrode and the second electrode and
a cavity is formed. In the release etch process of manufacturing
the structure, an etchant can pass through the hole to etch a
sacrificial layer between the first and the second electrodes to
form the cavity; therefore, the time needed for the process becomes
shorter.
Inventors: |
Miles; Mark W.; (San
Francisco, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
34216394 |
Appl. No.: |
11/240796 |
Filed: |
September 29, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10644312 |
Aug 19, 2003 |
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11240796 |
Sep 29, 2005 |
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Current U.S.
Class: |
257/415 ; 257/80;
438/69 |
Current CPC
Class: |
G09G 3/3466 20130101;
G02B 26/001 20130101; G02F 2203/03 20130101; G02F 1/216 20130101;
G02B 2006/12104 20130101; G02F 1/13725 20130101; B82Y 20/00
20130101; G01J 3/26 20130101; G02B 6/12 20130101 |
Class at
Publication: |
257/415 ;
257/080; 438/069 |
International
Class: |
H01L 29/84 20060101
H01L029/84; H01L 21/00 20060101 H01L021/00; H01L 33/00 20060101
H01L033/00; H01L 31/12 20060101 H01L031/12; H01L 27/15 20060101
H01L027/15; H01L 29/26 20060101 H01L029/26 |
Claims
1. A device suitable for an optical interference display cell
structure, the device comprising: a first electrode; a second
electrode including at least one hole, wherein the second electrode
is arranged about parallel with the first electrode; and a
supporter located between the first electrode and the second
electrode, wherein a cavity is formed between the supporter, the
first electrode and the second electrode, wherein when a structure
release etching process is used to remove a sacrificial layer
between the first electrode and the second electrode to form the
cavity, an etchant passes through the hole to etch the sacrificial
layer, so as to reduce the time needed in the structure release
etching process.
2. The device according to claim 1, wherein a diameter of the hole
is between about 1 micrometer and 10 micrometers.
3. The device according to claim 1, wherein a diameter of the hole
is between about 1 micrometer and 5 micrometers.
4. The device according to claim 1, wherein the structure release
etching process comprises a remote plasma etching process.
5. The device according to claim 4, wherein a precursor of a remote
plasma formed in the remote plasma etching process comprises an
etching reagent, and the etching reagent comprises at least one of
a fluorine base and a chlorine base.
6. The device release according to claim 4, wherein a precursor of
a remote plasma formed in the remote plasma etching process
comprises at least one of CF.sub.4, BCl.sub.3, NF.sub.3, and
SF.sub.6.
7. The device according to claim 1, wherein the etchant includes an
etching reagent, and the etching reagent comprises at least one of
a fluorine base and a chlorine base.
8. The device according to claim 1, wherein the etchant comprises
at least one of CF.sub.4, BCl.sub.3, NF.sub.3, and SF.sub.6.
9. The device according to claim 1, wherein a material of the
sacrificial layer comprises at least one of a dielectric material,
metal material and silicon material.
10. The device according to claim 1, wherein the second electrode
comprises a deformable electrode.
11. A method for manufacturing an optical interference display
device disposed on a substrate, the method comprising: forming a
first electrode on the substrate; forming a sacrificial layer on
the first electrode; forming at least two openings in the
sacrificial layer and the first electrode to define a position of
the optical interference display device; forming a supporter in
each of the openings; forming a second electrode on the sacrificial
layer and the supporter in each of the openings, wherein the second
electrode includes at least one hole, and the hole exposes the
sacrificial layer; and removing the sacrificial layer by a remote
plasma etching process.
12. The method according to claim 11, wherein the second electrode
comprises a deformable electrode.
13. The method according to claim 11, wherein a diameter of the
hole is between about 1 micrometer and 10 micrometers.
14. The method according to claim 11, wherein a diameter of the
hole is between about 1 micrometer and 5 micrometers.
15. The method for according to claim 11, wherein a precursor of a
remote plasma formed in the remote plasma etching process comprises
an etching reagent, and the etching reagent comprises at least one
of a fluorine base and a chlorine base.
16. The method for according to claim 11, wherein a precursor of a
remote plasma formed in the remote plasma etching process comprises
at least one of CF.sub.4, BCl.sub.3, NF.sub.3, and SF.sub.6.
17. The method according to claim 11, wherein a material of the
sacrificial layer comprises at least one of a dielectric material,
metal material and silicon material.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part, and hereby
incorporates by reference the entire disclosure, of U.S. patent
application Ser. No. 10/644,312, filed Aug. 19, 2003.
[0002] Moreover, this application incorporates by reference U.S.
patent application Ser. No. 11/090,911, filed Mar. 25, 2005; U.S.
patent application Ser. No. 11/150,496, filed Jun. 10, 2005; U.S.
Pat. No. 5,835,255, issued Nov. 10, 1998; U.S. Pat. No. 5,986,796,
issued Nov. 16, 1999; U.S. Pat. No. 6,040,937, issued Mar. 21,
2000; U.S. Pat. No. 6,055,090, issued Apr. 25, 2000; U.S. Pat. No.
6,650,455, issued Nov. 18, 2003; U.S. Pat. No. 6,674,562, issued
Jan. 6, 2004; U.S. Pat. No. 6,741,377, issued May 25, 2004; and
U.S. Pat. No. 6,870,654, issued Mar. 22, 2005.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to a structure of a structure
release and a method for manufacturing the same, and more
particularly, the present invention relates to a structure of a
structure release and a method for manufacturing the same adapted
for an interference display cell.
[0005] 2. Description of the Related Art
[0006] In a microelectromechanical system (MEMS), the development
of a sacrificial layer technique has become a key factor for
manufacturing a suspended structure, such as a cantilever, a beam,
a membrane, a channel, a cavity, a joint or hinge, a link, a crank,
a gear or a rack, to name a few. A structure release etching
process is adapted for removing a sacrificial layer, so a structure
of a structure release in a microelectromechanical system has an
influence on the process of removing the sacrificial layer.
[0007] A conventional structure release etching process is first
introduced with an interference display cell as an example. The
interference display cell, a kind of a microelectromechanical
system, is used to fabricate a planar display. Planar displays have
great superiority in the portable display device and limited-space
display market because they are lightweight and small. To date, in
addition to liquid crystal displays (LCD), organic
electro-luminescent displays (OLED), and plasma display panels
(PDP), a mode of optical interference displays is another option
for planar displays.
[0008] U.S. Pat. No. 5,835,255 discloses an array of display cells
of visible light that can be used in a planar display. Referring to
FIG. 1, FIG. 1 illustrates a cross-sectional view of a conventional
display cell.
[0009] Every optical interference display cell 100 comprises two
walls, wall 102 and wall 104. The wall 102 and the wall 104 are
supported by supporters 106, and a cavity 108 is subsequently
formed between the wall 102, the wall 104 and the supporters 106.
The distance between the wall 102 and the wall 104, that is, the
length of the cavity 108, is D. Either the wall 102 or the wall 104
is a semi-transmissible/semi-reflective layer with an absorption
rate that partially absorbs visible light, and the other is a light
reflective layer that is deformable when voltage is applied. When
the incident light passes through the wall 102 or the wall 104 and
into the cavity 108, in wavelengths (.lamda.) of all visible light
spectra of the incident light, only visible light with a wavelength
.lamda..sub.1 corresponding to formula 1.1 can generate a
constructive interference and can be emitted, that is, 2D=N.lamda.
(1.1) where N is a natural number.
[0010] When the length D of the cavity 108 is equal to half of the
wavelength multiplied by any natural number, a constructive
interference is generated and a sharp light wave is emitted. In the
meantime, if an observer follows the direction of the incident
light, a reflected light with wavelength .lamda..sub.1 can be
observed. Therefore, the optical interference display cell 100 is
"open".
[0011] FIG. 2 illustrates a cross-sectional view of a conventional
display cell after a voltage is applied. Referring to FIG. 2, while
driven by the voltage, the wall 104 is deformed and falls down
towards the wall 102 due to the attraction of static electricity.
At this time, the distance between the wall 102 and the wall 104,
that is, the length of the cavity 108, is not exactly equal to
zero, but is d, which can be equal to zero. If D in formula 1.1 is
replaced with d, only visible light with a wavelength .lamda..sub.2
satisfying formula 1.1 in wavelengths .lamda. of all visible light
spectra of the incident light can generate a constructive
interference, be reflected by the wall 104, and pass through the
wall 102. Because the wall 102 has a high light absorption rate for
light with wavelength .lamda..sub.2, all the incident light in the
visible light spectrum is filtered out and an observer who follows
the direction of the incident light cannot observe any reflected
light in the visible light spectrum. Therefore, the optical
interference display cell 100 is now "closed".
[0012] FIG. 3A and FIG. 3B illustrate a method for manufacturing a
conventional display cell. Referring to FIG. 3A, a first electrode
110 and a sacrificial layer 111 are formed in sequence on a
transparent substrate 109, and opening 112, which is suitable for
forming a supporter therein, is formed in the first electrode 110
and the sacrificial layer 111. Then, a supporter 106 is formed in
the opening 112. Next, an electrode 114 is formed on the
sacrificial layer 111 and the supporter 106. Subsequently,
referring to FIG. 3B, the sacrificial layer 111 shown in FIG. 3A is
removed by a release etching process to form a cavity 116, which is
located in the position of the sacrificial layer 111, and the
length D of the cavity 116 is the thickness of the sacrificial
layer 111.
[0013] In a microelectromechanical process, a micro suspended
structure is fabricated by use a sacrificial layer. A suspended
movable microstructure is fabricated by a selective etching between
a device structure layer and the sacrificial layer to remove the
sacrificial layer and leave the structure layer, and this process
is called a structure release etching. The difference between the
structure release etching process and an IC process is that in the
structure release etching process, the selective etching is an
isotropic etching, so that an undercut or an under etching is
formed in the structure layer for smooth separation of the
structure layer and the substrate.
[0014] The most popular structure release etching process is a wet
structure release process. In the wet structure release process, a
rinsing step and a drying step usually have to be performed after
etching, and a microstructure can substantially be suspended above
the substrate. However, during the wet structure release process,
it is quite easy for the structure and the substrate to stick
together, thereby resulting in failure of the device. A dry etching
process using xenon difluoride (XeF.sub.2) as an etchant can be
used to solve the problems resulted in the wet etching process.
[0015] Xenon difluoride is in a solid state at normal temperature
and normal pressure, and is sublimated into the gaseous state at
low pressure. Xenon difluoride has great etching selectivity on
silicon materials, such as monocrystalline silicon, polysilicon and
amorphous silicon, and some metals, such as molybdenum (Mo),
molybdenum alloy and so on. Xenon is an inert gas, and xenon
difluoride is quite unstable. The etching mechanism of xenon
difluoride is that two fluorine free radicals are brought to the
reaction positions by xenon, and when xenon difluoride contacts the
material to be etched, xenon difluoride decomposes to release these
two fluorine free radicals. Because the isotropic etching effect of
xenon difluoride is great, xenon difluoride has an excellent
capacity for lateral etching. In a microelectromechanical system
process, xenon difluoride is used as an etchant to remove a
sacrificial layer in a structure release etching process.
[0016] Referring to FIG. 4, FIG. 4 illustrates a top view of a
conventional optical interference display cell. The optical
interference display cell 200 includes separation structures 202,
such as defined by dotted lines 2021, located on two opposite sides
of the optical interference display cell 200, and supporters 204
located on the other two opposite sides of the optical interference
display cell 200. The separation structures 202 and the supporters
204 are located between two electrodes. There are gaps between the
supporters 204, and the supporters 204 and the separation
structures 202. The gaseous xenon difluoride permeates through the
gaps and etches a sacrificial layer (not shown in FIG. 4). The rate
of a structure release etching process with an etchant of the
gaseous xenon difluoride changes with the different materials of
the sacrificial layers desired to be etched. Typically, the etching
rate can be greater than 10 micrometers per minute, and even can be
up to 20-30 micrometers per minute for some materials. For the size
of the present optical interference display cell, one structure
release etching process only takes dozens of seconds to 3
minutes.
[0017] Although the structure release etching process performed
with the etchant of gaseous xenon difluoride has the aforementioned
advantages, a disadvantage of the high cost of the structure
release etching process results from the character of xenon
difluoride itself. Xenon difluoride is expensive, and is
particularly sensitive to moisture and is unstable. When xenon
difluoride contacts moisture, hydrogen fluoride is produced.
Hydrogen fluoride is not only dangerous, but also reduces
efficiency of etching. Besides, the structure release etching
process performed using xenon difluoride as an etchant is rare in
semiconductor processes and typical planar display processes, so
etchers that are maturely developed in the semiconductor processes
and the liquid crystal display processes are unsuitable for the
structure release etching process with xenon difluoride etchant.
The process apparatuses used in semiconductor or typical planar
display can be continuously used in most of the main processes of
the optical interference display, but the structure release etching
process needs a totally different apparatus design. To reorganize
and consolidate the process apparatuses would be an obstacle to the
development and throughput of the optical interference display.
SUMMARY OF THE INVENTION
[0018] The development of the etching apparatus with an etchant of
xenon difluoride is not maturing, which is disadvantageous to the
development and throughput of the optical interference display, and
the etchant xenon difluoride is expensive and unstable. Therefore,
if etching process apparatuses used in semiconductor or typical
planar display can be applied to perform a structure release
etching process, the process apparatuses of the optical
interference display are easily reorganized and consolidated, and
the structure release etching process can be performed cheaply.
[0019] The reason that the etching apparatus used in typical
semiconductor or planar display is not suitable for use in the
structure release etching process is the poor capacity for lateral
etching, and even though an etchant with a great etching property,
for example, nitrogen trifluoride (NF.sub.3) or sulphur
hexafluoride (SF.sub.6), is used, the etching rate is only between
3 micrometers and 10 micrometers per minute. This is slower than
that for using xenon difluoride as an etchant by several to dozens
of times. Therefore, this is very disadvantageous to throughput of
the optical interference display.
[0020] Therefore, an objective of the present invention is to
provide a structure of a structure release suitable for an optical
interference display cell structure. Time needed for the structure
etching process can be greatly reduced and throughput of the
optical interference display can be increased.
[0021] Another objective of the present invention is to provide a
structure of a structure release suitable for an optical
interference display cell structure, in which a xenon difluoride
process is not needed to perform a structure release etching,
thereby avoiding the difficulties resulting from reorganizing and
consolidating the process apparatuses.
[0022] Still another objective of the present invention is to
provide a structure release etching process for a structure of a
structure release suitable for an optical interference display cell
structure. In the structure release etching process, an etching
reagent including a fluorine base or a chlorine base, such as
CF.sub.4, BCl.sub.3, NF.sub.3, or SF.sub.6 and so on, can be used
to replace xenon difluoride to perform the structure release
etching, thereby lowering producing cost.
[0023] Yet another objective of the present invention is to provide
a structure release etching process for a structure of a structure
release suitable for an optical interference display cell
structure. The structure release etching process can use a
conventional etching apparatus, so the difficulties resulting from
reorganizing and consolidating the process apparatuses can be
avoided.
[0024] According to the aforementioned objectives of the present
invention, one preferred embodiment of the present invention takes
an optical interference display as an example to illustrate how to
apply the present invention to a microelectromechanical system. An
optical interference display cell structure includes a first
electrode and a second electrode, the two electrodes being
supported by a supporter, which is located between the two
electrodes. A plurality of holes are located on the second
electrode, and the holes pass. through the second electrode and
expose a sacrificial layer under the second electrode. With the
holes in the second electrode, etching plasma can etch the exposed
sacrificial layer through the holes, so as to accelerate a
structure release etching process. Therefore, the etching process
using an etchant including a fluorine base or a chlorine base, such
as CF.sub.4, BCl.sub.3, NF.sub.3, or SF.sub.6 and so on, suitable
for conventional semiconductor or typical planar display process
can be used to perform a structure release etching process of the
optical interference display cell, and process time of the
structure release etching process is commensurate with that of
xenon difluoride process. Certainly, the etching reagents including
a fluorine base or a chlorine base can be adapted and mixed to form
an etchant for etching the sacrificial layer.
[0025] In addition, the present invention preferably uses remote
plasma. A plasma is first produced in a plasma generator, and after
portion or all of the charged composition in the plasma is filtered
out, the remaining plasma, the remote plasma, is sent into a
chamber to perform a reaction. Free radicals are the main
composition of the remote plasma, so a life cycle of the remote
plasma is longer and the structure release etching of the
sacrificial layer is performed efficiently. Besides, the free
radicals are not charged and not easily affected by an electric
field, so the effect of isotropic etching is better for being
beneficial to lateral etching.
[0026] According to the optical interference display cell structure
and the method for manufacturing the same of the present invention,
the holes in the second electrode can indeed reduce the time taken
in the structure release etching, to make it possible for a
conventional etching process to replace a xenon difluoride etching
process, and to avoid the difficulties resulting from reorganizing
and consolidating the process apparatuses. The use of the remote
plasma increases the lift cycle of the etching plasma and the
lateral etching capacity of the plasma, accelerates the rate of the
structure release etching, decrease the time needed in the
structure release etching, and increases the throughput of the
optical interference display.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] These and other features, aspects, and advantages of the
present invention will be more fully understood by reading the
following detailed description of the preferred embodiment, with
reference made to the accompanying drawings as follows:
[0028] FIG. 1 illustrates a cross-sectional view of a conventional
display cell;
[0029] FIG. 2 illustrates a cross-sectional view of a conventional
display cell after a voltage is applied;
[0030] FIG. 3A and FIG. 3B illustrate a method for manufacturing a
conventional display cell;
[0031] FIG. 4 illustrates a top view of a conventional optical
interference display cell;
[0032] FIG. 4A illustrates a cross-sectional view of the structure
shown in FIG. 4 along cross-sectional line I-I';
[0033] FIG. 5 illustrates a top view of an optical interference
display cell in accordance with a preferred embodiment of the
present invention;
[0034] FIG. 5A illustrates an enlargement of a cross-sectional view
of a circle 308 shown in FIG. 5 along cross-sectional line II-II';
and
[0035] FIG. 6A, FIG. 6B, and FIG. 6C illustrate a method for
manufacturing an optical interference display cell structure in
accordance with a preferred embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0036] In order to make the illustration of a structure of a
structure release and a method for manufacturing the same provided
in the present invention more clear, an embodiment of the present
invention herein takes an optical interference display cell
structure and a manufacturing method thereof for example, to
illustrate how to apply the structure of the structure release and
the method for manufacturing the same disclosed in the present
invention, and to further explain advantages of the present
invention according to the disclosure of the embodiment.
[0037] FIG. 5 illustrates a top view of an optical interference
display cell in accordance with a preferred embodiment of the
present invention. Referring to FIG. 5, an optical interference
display cell 300 includes an electrode 301, separation structures
302, such as defined by a dotted line 3021, and supporters 304. The
separation structures 302 are located on two opposite sides of the
optical interference display cell 300. The supporters 304 are
located on another two opposite sides of the optical interference
display cell 300, and the separation structures 302 and the
supporters 304 are located between the electrode 301 and another
electrode (not shown in FIG. 5). The electrode 301 includes at
least one hole 306, which passes through the electrode 301. In
order to enable remote plasma to diffuse efficiently into the hole
306, the diameter of the hole 306 is preferably not less than 1
micrometer. As the diameter of the hole 306 increases, the etching
time decreases, but the larger hole 306 is not beneficial to the
resolution of the optical interference display cell 300. Therefore,
the diameter of the hole 306 is preferably not greater than 10
micrometers. In conclusion, a preferred diameter of the hole 306 is
between about 1 micrometer and 5 micrometers. There are gaps
between the supporters 304, and between each of the supporters 304
and the separation structures 302, and etching plasma can permeate
through the gaps and the hole 306 and etch a sacrificial layer (not
shown in FIG. 5).
[0038] In the present embodiment, the size of the optical
interference display cell 300 is between about 50 micrometers and
100 micrometers. FIG. 4A illustrates a cross-sectional view of the
structure shown in FIG. 4 along cross-sectional line I-I'. The
gaseous xenon difluoride permeates through gaps 208 between the
supporters (not shown in FIG. 4A), and between the supporters and
the separation structures (not shown in FIG. 4A) to etch the
sacrificial layer 210 toward the directions indicated by arrowheads
206. Typically, it takes about dozens of seconds to three minutes
to finish a structure release etching process with gaseous xenon
difluoride, although the etching rate of gaseous xenon difluoride
varies with different materials of sacrificial layer to be etched.
The conventional process, in contrast, takes about 10 minutes to 20
minutes, and sometimes even more than 20 minutes, to perform a
structure release etching.
[0039] FIG. 5A illustrates an enlargement of a cross-sectional view
of a circle 308 shown in FIG. 5 along cross-sectional line II-II'.
Taking the optical interference display cell 300 illustrated in
FIG. 5 as an example, when remote plasma produced from an etching
reagent includes a fluorine base or a chlorine base, such as
CF.sub.4, BCl.sub.3, NF.sub.3, or SF.sub.6, and is used to perform
a structure release etching, the etching plasma not only permeates
through gaps 312 between the supporters (not shown in FIG. 5A), and
between the supporters and the separation structures (not shown in
FIG. 5A) to etch the sacrificial layer 314 toward the direction
indicated by an arrowhead 310, but also permeates through the hole
306 in the electrode 301 to etch the sacrificial layer 314 in the
direction indicated by arrowhead 316. It takes less than 5 minutes
to complete a structure release etching process, and typically,
about 1 minute to 3 minutes are needed.
[0040] The optical interference display cell structure disclosed in
the present invention enables the introduction of the conventional
etching process, so the xenon difluoride etching process, which is
expensive and not easy to reorganize and consolidate, is not
needed, thereby avoiding the difficulties resulting from
reorganizing and consolidating the process apparatuses.
[0041] FIG. 6A, FIG. 6B, and FIG. 6C illustrate a method for
manufacturing an optical interference display cell structure in
accordance with a preferred embodiment of the present invention.
Referring to FIG. 6A, a first electrode 402 and a sacrificial layer
406 are firmed on a transparent substrate 401 in sequence. The
material of the sacrificial layer 406 can be transparent material,
such as dielectric material, or opaque material, such as metal
material, polysilicon or amorphous silicon. In the embodiment,
polysilicon is used as the material of the sacrificial layer 406.
An opening 408 is formed in the first electrode 402 and the
sacrificial layer 406 by a photolithography process, and the
opening 408 is suitable for forming a supporter therein.
[0042] Then, a material layer 410 is formed on the sacrificial
layer 406 to fill up the opening 408. The material layer 410 is
suitable for forming the supporter, and the first material layer
410 generally is made of photosensitive materials such as
photoresists, or non-photosensitive polymer materials such as
polyester, polyamide or the like. If non-photosensitive materials
are used for forming the material layer 410, a photolithographic
etching process is required to define supporters in the material
layer 410. In this embodiment, the photosensitive materials are
used for forming the material layer 410, so merely a
photolithography process is required for patterning the material
layer 410.
[0043] Referring to FIG. 6B, supporters 412 are defined by
patterning the material layer 410 through a photolithography
process. Next, a second electrode 404 is formed on the sacrificial
layer 406 and the supporters 412. The second electrode 404 includes
at least one hole 414.
[0044] Subsequently, remote plasma is produced by using an etching
reagent including a fluorine base or a chlorine base, such as
CF.sub.4, BCl.sub.3, NF.sub.3, or SF.sub.6 and so on, as a
precursor to etch the sacrificial layer 406. The remote plasma
etches the sacrificial layer 406 not only through the gaps (not
shown in FIG. 6B) between the supporters, but also through the hole
414, so the sacrificial layer 406 is removed by a structure release
etching process, and a cavity 416 such as illustrated in FIG. 6C is
formed.
[0045] In the present invention, the materials suitable for forming
the supporters 412 include positive photoresists, negative
photoresists, and all kinds of polymers, such as acrylic resins and
epoxy resins.
[0046] According to the optical interference display cell disclosed
in the embodiment, at least one hole is formed in a deformable
electrode, and the number of holes relates to the size of the
optical interference display cell and the size of the hole. For
example, if the size of the optical interference display cell is
between about 50 micrometers and 100 micrometers, and the diameter
of a hole is between 1 micrometer and 5 micrometers, 4 to 16 holes
are needed to shorter time taken in a structure release etching
process to an acceptable level. On the contrary, if the size of the
optical interference display cell is less than 50 micrometers, the
number of the holes may be less than 4, and even only one hole is
needed to shorter time taken in a structure release etching process
to an acceptable level.
[0047] The hole in the deformable electrode can substantially
reduce time of a structure release etching process, so that etching
processes suitable for semiconductor or planar display processes
can be applied in the structure release etching process of the
optical interference display cell structure, thereby avoiding the
difficulties resulting from reorganizing and consolidating the
xenon difluoride etching process apparatuses and the other
deposition process apparatuses. Furthermore, fabrication cost can
be reduced because the expensive xenon difluoride etching process
is not needed.
[0048] As is understood by a person skilled in the art, the
foregoing preferred embodiments of the present invention are
illustrative of the present invention rather than limiting of the
present invention. The structure of the structure release and the
method for manufacturing the same disclosed in the present
invention can be applied in various microelectromechanical
structure systems. It is intended that various modifications and
similar arrangements be included within the spirit and scope of the
appended claims, the scope of which should be accorded the broadest
interpretation so as to encompass all such modifications and
similar structure.
* * * * *