U.S. patent application number 10/011569 was filed with the patent office on 2002-05-02 for micro structure and its manufacture method.
This patent application is currently assigned to SUMITOMO HEAVY INDUSTRIES, LTD.. Invention is credited to Katoh, Takanori, Zhang, Yanping.
Application Number | 20020051864 10/011569 |
Document ID | / |
Family ID | 22268643 |
Filed Date | 2002-05-02 |
United States Patent
Application |
20020051864 |
Kind Code |
A1 |
Katoh, Takanori ; et
al. |
May 2, 2002 |
Micro structure and its manufacture method
Abstract
A laminated substrate is prepared, the laminated substrate
having two layers including a first film and a second film in tight
contact with the first film, the second film being made of a
material capable of being etched with synchrotron radiation light.
A mask member with a pattern is disposed in tight contact with the
surface of the second film of the laminated structure or at a
distance from the surface of the second film, the pattern of the
mask member being made of a material not transmitting the
synchrotron radiation light. The synchrotron radiation light is
applied on a partial surface area of the second film via the mask
member to etch the second film where the synchrotron radiation
light is applied and to expose a partial surface area of the first
film on the bottom of an etched area.
Inventors: |
Katoh, Takanori;
(Kusatsu-shi, JP) ; Zhang, Yanping; (Kusatsu-shi,
JP) |
Correspondence
Address: |
FRISHAUF, HOLTZ, GOODMAN, LANGER & CHICK, P.C.
25th Floor
767 Third Avenue
New York
NY
10017-2023
US
|
Assignee: |
SUMITOMO HEAVY INDUSTRIES,
LTD.
5-9-11, Kita-shinagawa, Shinagawa-ku
Tokyo
JP
|
Family ID: |
22268643 |
Appl. No.: |
10/011569 |
Filed: |
November 6, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10011569 |
Nov 6, 2001 |
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09602274 |
Jun 23, 2000 |
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09602274 |
Jun 23, 2000 |
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09098289 |
Jun 16, 1998 |
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Current U.S.
Class: |
428/138 |
Current CPC
Class: |
G03F 7/09 20130101; Y10T
428/24339 20150115; B32B 3/02 20130101; G03F 7/075 20130101; G03F
7/2039 20130101; G03F 7/00 20130101; B32B 27/06 20130101; B81C
1/00126 20130101; Y10T 428/24331 20150115 |
Class at
Publication: |
428/138 |
International
Class: |
B32B 003/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 19, 1997 |
JP |
HEI 9-163148 |
Claims
What is claimed is:
1. A method of manufacturing a micro structure comprising the steps
of: preparing a laminated substrate of two layers including a first
film and a second film in tight contact with the first film, the
second film being made of a material capable of being etched with
synchrotron radiation light; disposing a mask member with a pattern
in tight contact with a surface of the second film of the laminated
structure or at a distance from the surface of the second film, the
pattern of the mask member being made of a material not
substantially transmitting the synchrotron radiation light; and
applying the synchrotron radiation light on a partial surface area
of the second film via the mask member to etch the second film
where the synchrotron radiation light is applied and to expose a
partial surface area of the first film on a bottom of an etched
area.
2. A method according to claim 1, wherein the first film is made of
a conductive material and the method further comprises the steps
of: after said step of exposing the partial surface area of the
first film, depositing a metal member through galvanizing on the
exposed partial surface area of the first film to fill with the
metal member a region where the second film is removed; and
applying the synchrotron radiation light or an electron beam to the
laminated substrate to remove the left second film.
3. A method according to claim 1, further comprising the step of
molding plastics by using the first film and the second film left
on the partial surface area on the first film, after said step of
exposing the partial surface area of the first film.
4. A method according to claim 1, further comprising the steps of:
after said step of exposing the partial surface area of the first
film, depositing a metal member through galvanizing on the exposed
partial surface area of the first film to fill with the metal
member a region where the second film is removed; and patterning
the first film to partially leave the first film at an area
corresponding to the metal member and a circumferential area of the
metal member.
5. A method according to claim 1, wherein the second film is made
of polytetrafluoroethylene.
6. A method according to claim 2, wherein the second film is made
of polytetrafluoroethylene.
7. A method according to claim 3, wherein the second film is made
of polytetrafluoroethylene.
8. A method according to claim 4, wherein the second film is made
of polytetrafluoroethylene.
9. A method according to claim 1, wherein said step of disposing
the mask member includes the steps of: depositing a metal film on a
surface of the second film; coating a photoresist film on a surface
of the metal film; exposing the photoresist film via a photo mask;
developing the exposed photoresist film to form a resist pattern;
and etching the metal film by using the resist pattern as a mask to
form the mask member of a left metal film.
10. A method according to claim 2, wherein said step of disposing
the mask member includes the steps of: depositing a metal film on a
surface of the second film; coating a photoresist film on a surface
of the metal film; exposing the photoresist film via a photo mask;
developing the exposed photoresist film to form a resist pattern;
and etching the metal film by using the resist pattern as a mask to
form the mask member of a left metal film.
11. A method according to claim 3, wherein said step of disposing
the mask member includes the steps of: depositing a metal film on a
surface of the second film; coating a photoresist film on a surface
of the metal film; exposing the photoresist film via a photo mask;
developing the exposed photoresist film to form a resist pattern;
and etching the metal film by using the resist pattern as a mask to
form the mask member of a left metal film.
12. A method according to claim 4, wherein said step of disposing
the mask member includes the steps of: depositing a metal film on a
surface of the second film; coating a photoresist film on a surface
of the metal film; exposing the photoresist film via a photo mask;
developing the exposed photoresist film to form a resist pattern;
and etching the metal film by using the resist pattern as a mask to
form the mask member of a left metal film.
13. A method according to claim 9, further comprising the step of:
removing the left metal film after said step of etching the second
film and exposing the partial surface area of the first film on the
bottom of the etched area.
14. A method according to claim 10, further comprising the step of:
removing the left metal film after said step of etching the second
film and exposing the partial surface area of the first film on the
bottom of the etched area.
15. A method according to claim 11, further comprising the step of:
removing the left metal film after said step of etching the second
film and exposing the partial surface area of the first film on the
bottom of the etched area.
16. A method according to claim 12, further comprising the step of:
removing the left metal film after said step of etching the second
film and exposing the partial surface area of the first film on the
bottom of the etched area.
17. A micro structure comprising: a first film made of a material
having an etching resistance to radiation light different from an
etching resistance of polytetrafluoroethylene; and a second film in
tight contact with said first film and made of
polytetrafluoroethylene, said second film being patterned, and a
surface of said first film being exposed in an area where a pattern
of said second film is not formed.
18. A micro structure comprising: a polytetrafluoroethylene film
having a through hole; and a metal member filling the through hole.
Description
[0001] This application is based on Japanese Patent Application No.
HEI-9-163148 filed on Jun. 19, 1997, the entire contents of which
are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] a) Field of the Invention
[0003] The present invention relates to a micro structure and its
manufacture method, and more particularly to micro machines and a
manufacture method suitable for fabrication of micro machines.
[0004] b) Description of the Related Art
[0005] As a manufacture method for micro structures, techniques of
Lithographie Galvanoformung Abformung (LIGA) are known.
Conventional LIGA techniques will be briefly described.
[0006] A photoresist film is formed on a conductive support
substrate. This photoresist film is locally exposed with X-rays by
using a LIGA mask having a high contrast, and thereafter developed
and patterned. Regions where the photoresist film is removed are
filled with metal by galvanizing. As the photoresist film is
removed, a micro structure made of metal can be formed.
[0007] With LIGA techniques, it takes generally several hours to
expose and develop a photoresist film. A photoresist mask having a
high contrast is also required.
SUMMARY OF THE INVENTION
[0008] It is an object of the present invention to provide a method
of manufacturing a micro structure capable of shortening a process
time.
[0009] It is another object of the present invention to provide a
composite micro structure made of a combination of different
materials.
[0010] According to one aspect of the present invention, there is
provided a method of manufacturing a micro structure comprising the
steps of: preparing a laminated substrate of two layers including a
first film and a second film in tight contact with the first film,
the second film being made of a material capable of being etched
with synchrotron radiation light; disposing a mask member with a
pattern in tight contact with a surface of the second film of the
laminated structure or at a distance from the surface of the second
film, the pattern of the mask member being made of a material not
substantially transmitting the synchrotron radiation light; and
applying the synchrotron radiation light on a partial surface area
of the second film via the mask member to etch the second film
where the synchrotron radiation light is applied and to expose a
partial surface area of the first film on a bottom of an etched
area.
[0011] Since the second film is etched by applying radiation light,
a process time can be shortened as compared to LIGA techniques
which utilizes exposure and development processes.
[0012] According to another aspect of the present invention, there
is provided a micro structure comprising: a first film made of a
material having an etching resistance to radiation light different
from an etching resistance of polytetrafluoroethylene; and a second
film in tight contact with the first film and made of
polytetrafluoroethylene, the second film being patterned, and a
surface of the first film being exposed in an area where a pattern
of the second film is not formed.
[0013] By using this micro structure, a micro machine made of
plastics can be formed.
[0014] According to another aspect of the present invention, there
is provided a micro structure comprising: a polytetrafluoroethylene
film having a through hole; and a metal member filling the through
hole.
[0015] A micro structure can be formed by selecting each material
of each region of the structure so as to satisfy the mechanical and
electrical characteristics required for the region.
[0016] As described above, it is possible to perform micro
processing by using radiation light. A micro composite material can
be formed by filing a micro space in a micro structure with another
material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1A is a schematic diagram showing a working system used
by the embodiments of the invention. and FIGS. 1B and 1C are
schematic cross sectional views of the working system.
[0018] FIG. 2 is a front view of a drive mechanism used by the
working system shown in FIGS. 1A to 1C.
[0019] FIGS. 3A to 3F are cross sectional views illustrating
processes of a method of manufacturing a micro structure according
to a first embodiment of the invention.
[0020] FIGS. 4A to 4C are cross sectional views illustrating
processes of a method of manufacturing a micro structure according
to a modification of the first embodiment.
[0021] FIGS. 5A to 5C are cross sectional views illustrating
processes of a method of manufacturing a micro structure according
to a second embodiment of the invention.
[0022] FIGS. 6A to 6C are cross sectional views illustrating
processes of a method of manufacturing a micro structure according
to a third embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] FIG. 1A is a schematic diagram showing a working system used
by a method of manufacturing a micro structure according to the
embodiments. A synchrotron radiation light (SR light) is emitted
along an optical axis of an orbit of electrons accumulated in a
synchrotron. A workpiece 4 is placed at a distance L from the
radiation light source on the optical axis 5. In front of the
workpiece 4, a mask 3 is disposed at a distance G. The electron
orbit 1, workpiece 4 and mask 3 are housed in the same vacuum
chamber.
[0024] The mask 3 has regions substantially not transmitting SR
light and regions substantially transmitting the SR light. A region
substantially transmitting SR light is a region through which SR
light having an intensity strong enough to process the workpiece
passes, and a region substantially not transmitting SR light is a
region through which SR light cannot pass or even if it passes, the
SR light is attenuated to an intensity not enough to process the
workpiece.
[0025] The mask used in the embodiments is made of a copper plate
of 10 to 100 .mu.m in thickness, and has a pattern of a desired
micro component. The mask may be made of other metal instead of
copper. The thickness of the mask may be about 2 to 10 .mu.m.
[0026] The SR light 2 is applied to the surface of the workpiece 4.
A surface region of the workpiece 4 where the SR light is applied
is removed through etching. By forming a micro pattern on the
surface of the mask 3, the surface of the workpiece 4 can be
processed to have a micro pattern.
[0027] FIG. 1B is a cross sectional view of a working unit. In a
vacuum chamber 20, a sample holding stage 14 is mounted. A
workpiece 4 is placed on the sample holding surface of the sample
holding stage 14. A mask 3 is disposed in front of the workpiece 4
by a mask holder 17. The mask 3 may be set in contact with the
surface of the workpiece 4, or spaced apart therefrom by some
distance. In processing the workpiece 4, SR light 2 is applied from
the left side in FIG. 1B to the surface of the workpiece 4 through
the mask 3.
[0028] The sample holding stage 14 is made of, for example,
ceramics and has a heater 8 embedded therein. Lead wires of the
heater 8 are connected to one ends of terminals which pass through
the wall of the vacuum chamber 20, and the other ends of the
terminals are connected via cables to a power source 7 which
supplies current to the heater 8. As current flows through the
heater 8, the workpiece 4 is heated.
[0029] A thermocouple 23 is mounted on the sample holding surface
of the sample holding stage 14. Lead wires of the thermocouple 23
extend via a lead wire output port 22 to the outside of the vacuum
chamber 20, and are connected to a temperature controller 9. The
lead wire output port 22 is sealed, for example, by solder. This
temperature controller 9 controls the power source 7 to regulate
the amount of current flowing through the heater 8 and set the
temperature of the sample holding surface to a desired
temperature.
[0030] FIG. 1C shows another example of the structure of the sample
holding stage. A gas flow path 16 is formed inside of a sample
holding stage 15. Gas at a desired temperature is flowed through
the gas flow path 16 to exchange heat with a workpiece 4, to
thereby maintain the workpiece at a desired temperature.
[0031] FIG. 2 shows a Z-axis direction drive mechanism for a
workpiece 4 and a mask 3. A sample holding stage 14 is mounted on
the drive mechanism 10, with its sample holding surface being set
generally perpendicular to an optical axis direction (Y-axis
direction) of SR light 2. The workpiece 4 is mounted on the sample
holding surface of the sample holding stage 14, and the mask 3 is
disposed at a distance G from the surface of the workpiece 4.
[0032] The drive mechanism 10 has handles 11, 12 and 13. As the
handle 11 is rotated, the sample holding stage 14 moves in the
up/down direction as in FIG. 2 (Z-axis direction). The handle 11 is
rotated by using stepping motor to move the stage at a desired
constant speed.
[0033] As the handles 12 and 13 are rotated, the sample holding
stage 14 moves in a direction vertical to the drawing sheet (X-axis
direction) and in the Y-axis direction. With these handles 12 and
13, the position of the sample holding stage 14 can be minutely
adjusted both in the X- and Y-axis directions.
[0034] As the handle 11 is rotated by using the stepping motor
while SR light 2 is applied to the surface of the workpiece 4, the
workpiece 4 moves along the Z-axis direction so that a relatively
large area can be processed with ease.
[0035] Next, a method of manufacturing a micro structure according
to the first embodiment of the invention will be described with
reference to FIGS. 3A to 3F.
[0036] As shown in FIG. 3A, a substrate 30 is prepared which is a
lamination of a metal film 31 and a polytetrafluoroethylene film 32
tightly coupled to the metal film 31. For example, the substrate 30
may be formed by depositing an Ni film and a Cu film through
galvanizing on a polytetrafluoroethylene film, or by placing a
polytetrafluoroethylene film on a Cu plate and heating and pressing
to adhere them through melting. In this embodiment, the thickness
of the metal film 31 is 20 .mu.m and the thickness of the
polytetrafluoroethylene film 32 is 300 .mu.m.
[0037] A mask member 33 is disposed at a predetermined distance
from the surface of the polytetrafluoroethylene film 32. The mask
member 33 is a stainless sheet having a plurality of slits of 100
.mu.m in width disposed at an interval of 200 .mu.m.
[0038] SR light 34 is applied via the mask member 33 to the
polytetrafluoroethylene film 32. Regions of the
polytetrafluoroethylene film 32 where the SR light 34 is applied
are etched and removed. Since the metal film 31 is not etched, the
etching stops when the surface of the metal film 31 is exposed.
[0039] The whole thickness of the polytetrafluoroethylene film 32
of 300 .mu.m in thickness could be etched in about 10 minutes at
the substrate temperature of 200.degree. C. through exposure of SR
light having a photon density of about 6.times.10.sup.15
photons/s.multidot.mm.sup.2. With conventional LIGA techniques,
exposure of about 2 to 3 hours and development of about 2 to 3
hours become necessary for a photoresist film having a thickness of
about 300 .mu.m. In this embodiment, it is possible to process a
polytetrafluoroethylene film in a short time.
[0040] FIG. 3B shows the surface of the metal film 31 partially
exposed. The polytetrafluoroethylene film 32 is formed with grooves
35 corresponding to the slits of the mask member 33.
[0041] As shown in FIG. 3C, metal such as Cu, Ni and Pt is
deposited through galvanizing on the surface of the metal film 31
exposed on the bottom of the groove 35. The groove 35 is therefore
filled with a metal material 36 such as Cu, Ni and Pt.
[0042] SR light or electron beams are applied to the left
polytetrafluoroethylene film 32. If SR light is applied, the
polytetrafluoroethylene film 32 is etched, whereas electron beams
are applied, the polytetrafluoroethylene film 32 deteriorates its
quality and changes to powder-like substances so that the
polytetrafluoroethylene film 32 can be easily removed.
[0043] FIG. 3D is a cross sectional view showing the substrate
after the polytetrafluoroethylene film 32 is removed. The metal
member 36 is left on the metal film 31. The metal members 36 are
disposed at a pitch of 100 .mu.m, each having a width of about 200
.mu.m. A micro structure made of a metal is therefore formed.
[0044] As shown in FIG. 3E, a plastics material 37a is flowed onto
the surface of the metal film 31 for molding the plastics material
37a. As the plastics material 37a is peeled off from the metal film
31, a micro structure 37 made of plastics is formed.
[0045] Next, a method of manufacturing a micro structure according
to a modification of the first embodiment will be described with
reference to FIGS. 4A to 4C.
[0046] As shown in FIG. 4A, a metal film 40 made of Cu or the like
is deposited to a thickness of 2 to 20 .mu.m on the surface of a
polytetrafluoroethylene film 32 of a laminated substrate 30 same as
that shown in FIG. 3A. A resist pattern 41 is formed on the metal
film 40. The resist pattern 41 is formed by coating a resist film
and exposing and developing it via a photo mask. This exposure is
performed using visual light or ultraviolet light. The photo mask
may be a mask commonly used in this field, such as a glass
substrate formed with a Cr pattern.
[0047] By using the resist pattern 41 as a mask, the metal film 40
is etched to form openings. After the openings are formed, the
resist pattern 41 is removed.
[0048] FIG. 4B is a cross sectional view of the substrate 30 and
metal film 40 after the resist pattern 41 is removed. Next, SR
light 42 is applied to the surface of the laminated substrate 30.
The polytetrafluoroethylene film 32 exposed in the openings of the
metal film 40 is etched.
[0049] FIG. 4C is a cross sectional view of the substrate 30 and
metal film 40 after the polytetrafluoroethylene film 32 is etched.
As the metal film 40 is removed, a micro structure similar to that
shown in FIG. 3B is formed.
[0050] With the method described with FIG. 3A, the mask member 33
is a metal sheet having slits. If it is necessary to make an
isolated light shielded area, the mask member 33 shown in FIG. 3A
cannot be used. In such a case, another mask member is used which
has a membrane made of material transmitting SR light such as SiC
and a pattern made of material shielding SR light such as Ti formed
on the membrane. However, these mask materials are expensive and
moreover have a weak mechanical strength and are not easy to
handle.
[0051] With the method shown in FIGS. 4A to 4C, a pattern is
transferred to the metal film 40 by using a usual mask for visual
light or ultraviolet light. Therefore, this method has advantages
of low cost and easy-to-handle. Furthermore, since the metal film
40 is in tight contact with the polytetrafluoroethylene film 32, it
is easy to form an isolated light shielding area.
[0052] Next, a method of manufacturing a micro structure according
to a second embodiment of the invention will be described with
reference to FIGS. 5A to 5C.
[0053] A laminated substrate 30 shown in FIG. 5A has the same
structure as that of the first embodiment shown in FIG. 3B.
[0054] As shown in FIG. 5B, a plastics material 45a is flowed onto
the surface of the substrate 30 to mold the plastics material 45a.
As the plastics material 45a is peeled off from the substrate 30, a
micro structure 45 made of plastics is formed as shown in FIG.
5C.
[0055] In the first embodiment, the metal film 31 and the micro
metal member 36 formed on the surface of the metal film 31 by
galvanizing are used as a mold. Instead, as in the second
embodiment, the processed polytetrafluoroethylene film 32 formed on
the surface of the metal film 31 may be used as a mold.
[0056] In the first and second embodiments, a
polytetrafluoroethylene film is used as a material to be processed
in a micro shape. Other material capable of being etched with SR
light may also be used, such as crystalline materials of NaCl, LiF
and the like.
[0057] Next, a method of manufacturing a micro structure according
to a third embodiment of the invention will be described with
reference to FIGS. 6A to 6C.
[0058] A laminated substrate 30 shown in FIG. 6A has the same
structure as that of the first embodiment shown in FIG. 3C. The
metal film 31 on the bottom of the substrate 30 is removed. If the
metal film 31 is made of Cu, it can be removed through etching
using, for example, sulfuric acid. While the metal film 31 is
etched, the opposite surface of the polytetrafluoroethylene film 32
is covered with a resist film or the like.
[0059] If an etching selection ratio of the metal film 31 to the
metal member 36 is small, etching is performed under the control of
etching time and stopped when the whole thickness of the metal film
31 is removed. If the etching selection ratio of the metal film 31
to the metal member 36 can be made large, only the metal film 31
can be easily etched and removed without strict time control.
[0060] FIG. 6B is a cross sectional view showing the structure of
FIG. 6A after the metal film 31 is removed. A fine composite
material can be formed, with the metal member 3 being filled in the
space of the polytetrafluoroethylene film 32. For example, a
composite material can be formed having a region requiring a
resistance to chemicals which is made of polytetrafluoroethylene
and a region requiring a mechanical strength or an electrical
conductivity which is made of metal.
[0061] In the process shown in FIG. 6B, although the metal film 31
is fully removed, it may be locally etched.
[0062] FIG. 6C shows another structure in which the metal film 31
is locally etched to leave it locally in an area corresponding to
the metal member 36 and its circumferential area. By locally
etching the metal film 31, adhesion between the
polytetrafluoroethylene region and the metal region can be enhanced
while insulation between respective metal regions is
maintained.
[0063] If it is not necessary to ensure insulation between
respective metal regions, the metal film 31 is not necessarily
removed.
[0064] In the above embodiments, the polytetrafluoroethylene film
having a thickness of about 300 .mu.m is processed. The thickness
is not limited thereto. However, since it takes a long process time
if the workpiece becomes thick, a suitable range of the thickness
of a workpiece is not thicker than 3000 .mu.m.
[0065] If a micro structure is used as a micro machine, this
structure is required to have a mechanical strength more or less.
It is therefore preferable to set the thickness of a workpiece to
30 .mu.m or thicker. However, if the micro structure is not
required to have a mechanical strength, the thickness is not
limited.
[0066] The present invention has been described in connection with
the preferred embodiments. The invention is not limited only to the
above embodiments. It is apparent that various modifications,
improvements, combinations, and the like can be made by those
skilled in the art.
* * * * *