U.S. patent application number 12/077434 was filed with the patent office on 2008-07-31 for modular board device, high frequency module, and method of manufacturing the same.
This patent application is currently assigned to SONY CORPORATION. Invention is credited to Akihiko Okubora.
Application Number | 20080178463 12/077434 |
Document ID | / |
Family ID | 30112323 |
Filed Date | 2008-07-31 |
United States Patent
Application |
20080178463 |
Kind Code |
A1 |
Okubora; Akihiko |
July 31, 2008 |
Modular board device, high frequency module, and method of
manufacturing the same
Abstract
The present invention is directed to a high frequency module
used for wireless communication module, and comprises a first
organic substrate (11) in which conductive pattern or patterns are
formed on the principal surface thereof and one element body (7) or
more are mounted, and a second organic substrate (12) in which a
recessed portion (22) is formed in correspondence with the area
where the element body or bodies (7) are mounted at the connecting
surface to the first organic substrate (11). In the state where the
second organic substrate (12) is connected to the first organic
substrate (11), an element body accommodating portion (24) which
seals the element body or bodies (7) is constituted by the recessed
portion (22), wherein the element body accommodating portion (24)
is adapted so that moisture resistance characteristic and oxidation
resistance characteristic are maintained.
Inventors: |
Okubora; Akihiko; (Kanagawa,
JP) |
Correspondence
Address: |
ROBERT J. DEPKE;LEWIS T. STEADMAN
ROCKEY, DEPKE & LYONS, LLC, SUITE 5450 SEARS TOWER
CHICAGO
IL
60606-6306
US
|
Assignee: |
SONY CORPORATION
|
Family ID: |
30112323 |
Appl. No.: |
12/077434 |
Filed: |
March 19, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10519765 |
Dec 28, 2004 |
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PCT/JP03/07827 |
Jun 19, 2003 |
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12077434 |
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Current U.S.
Class: |
29/830 ;
257/E21.511; 257/E21.518; 257/E23.002; 257/E23.114; 257/E23.181;
257/E23.193; 257/E25.03; 257/E25.031; 29/846 |
Current CPC
Class: |
H01L 2924/01006
20130101; H01L 2224/13144 20130101; H01L 23/564 20130101; H01L
2924/01013 20130101; H01L 2924/01023 20130101; H05K 2203/061
20130101; Y10T 29/49126 20150115; H01L 2924/00014 20130101; H01L
24/81 20130101; H01L 2924/01082 20130101; H01L 2924/09701 20130101;
H01L 2924/30105 20130101; H01L 2924/1461 20130101; H01L 2924/19042
20130101; H01L 2924/1461 20130101; Y10T 29/49155 20150115; H01L
2924/00 20130101; H01L 2924/00012 20130101; H05K 3/4602 20130101;
H05K 2201/0179 20130101; H01L 2924/00014 20130101; H01L 2924/00014
20130101; H01L 2924/12042 20130101; H01L 2924/19043 20130101; H01L
25/165 20130101; H01L 2924/014 20130101; H05K 1/0272 20130101; H05K
3/4697 20130101; H01L 23/552 20130101; H01L 2924/01073 20130101;
H01L 2924/01005 20130101; H01L 2924/181 20130101; H05K 3/4614
20130101; H01L 2224/73204 20130101; H01L 2924/16235 20130101; B81C
1/0023 20130101; H01L 2224/81801 20130101; H01L 2224/83102
20130101; H01L 24/48 20130101; H01L 2924/15151 20130101; H01L
2924/01029 20130101; H01L 2924/1617 20130101; H05K 1/0237 20130101;
H01L 23/04 20130101; H05K 1/186 20130101; H01L 2924/19041 20130101;
H01L 2223/6677 20130101; H01L 2924/12042 20130101; H01L 2924/01079
20130101; H01L 2924/01033 20130101; H05K 2201/09981 20130101; H01L
2224/48247 20130101; H01L 25/162 20130101; H05K 1/0218 20130101;
H01L 2924/181 20130101; H05K 1/16 20130101; H05K 2201/09072
20130101; H05K 2203/086 20130101; H01L 2924/14 20130101; H01L
2924/19105 20130101; H05K 2203/1147 20130101; H01L 2924/01047
20130101; H01L 2224/92125 20130101; H01L 2924/3025 20130101; H05K
2201/10053 20130101; H05K 2203/1178 20130101; H01L 23/10 20130101;
H01L 2924/01024 20130101; H01L 2924/16152 20130101; H01L 2224/16
20130101; H01L 2924/01004 20130101; H01L 2924/01078 20130101; H01L
2224/45099 20130101; H01L 2924/207 20130101; H01L 2224/45015
20130101; H01L 2924/00 20130101 |
Class at
Publication: |
29/830 ;
29/846 |
International
Class: |
H05K 3/36 20060101
H05K003/36; H05K 3/10 20060101 H05K003/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 3, 2002 |
JP |
2002-195022 |
Claims
1.-10. (canceled)
11. A method of manufacturing a module board device, including: a
step of mounting one element body or more onto the principal
surface of a first organic substrate in which a conductive pattern
or patterns has or have been formed; and a step of connecting a
second organic substrate, in which a recessed portion is formed in
correspondence with the area where the element body or bodies is or
are mounted at a connecting surface to the first organic substrate
in such a manner to seal the element body or bodies into an element
body accommodating space portion constituted by the recessed
portion so that the element body accommodating space portion is
constituted as a space portion in which moisture resistance
characteristic and oxidation resistance characteristic are
maintained, a step of forming an insulating resin layer onto the
entire surface of at least one second principal surface of the
first organic substrate and the second organic substrate of the
side opposite to a surface where the first organic substrate and
the second organic substrate are connected to each other, a step of
implementing polishing processing to the insulating resin layer to
allow the second principal surface to be a planarized (flattened)
build-up formation surface, and a step of forming one build-up
wiring layer or more including at least one kind of passive element
or more formed by the thin film technology or the thick film
technology on the build-up formation surface.
12. The method of manufacturing module board device as set forth in
claim 11, wherein the connecting step of the first organic
substrate and second organic substrate is performed within inactive
gas atmosphere.
13. The method of manufacturing module board device as set forth in
claim 11, wherein an air vent hole communicating with the element
body accommodating space portion is formed at the first organic
substrate or the second organic substrate, and subsequently to the
connecting step of the first organic substrate and the second
organic substrate, a step of deflating air within the element body
accommodating space portion through the air vent hole, a step of
filling inactive gas into the element body accommodating portion
through the air vent hole, and a step of closing the air vent hole
are implemented.
14. The method of manufacturing module board device as set forth in
claim 11, wherein the connecting step of the first organic
substrate and the second organic substrate consists of a step of
sticking adhesive sheet to either one connecting surface of the
first organic substrate and the second organic substrate, a step of
combining the first organic substrate and the second organic
substrate after undergone positioning, and a step of allowing the
first organic substrate and the second organic substrate to be in
pressure contact with each other.
15. The method of manufacturing module board device as set forth in
claim 11, wherein the connecting step of the first organic
substrate and the second organic substrate consists of a step of
combining the first organic substrate and the second organic
substrate after undergone positioning, and a step of applying
ultrasonic wave to a connecting surface of the first organic
substrate and the second organic substrate to weld it.
16. The method of manufacturing module board device as set forth in
claim 11, including: a step of forming a shield layer by shield
material consisting of silicon oxide, silicon nitride, silicon
carbide, boron nitride or Diamond Like Carbon of at least one layer
or more which can be formed as film under low temperature condition
at an element body mounting area and a recessed portion which
constitute at least the element accommodating space portion of the
first organic substrate and the second organic substrate, wherein
the element body accommodating space portion is constituted by the
shield layer as a space portion in which moisture resistance
characteristic and oxidation resistance characteristic are
maintained.
17. The method of manufacturing module board device as set forth in
claim 11, including a step of forming a shield layer consisting of
metallic film of at least one layer or more at an element body
mounting area and a recessed portion which constitute at least the
element accommodating space portion of the first organic substrate
and the second organic substrate, wherein the element accommodating
space portion is constituted by the shield layer as a space portion
in which electromagnetic wave characteristic is maintained along
with moisture resistance characteristic and oxidation resistance
characteristic.
18.-21. (canceled)
22. A method of manufacturing a high frequency module, including; a
step of manufacturing a base substrate portion via a step of
mounting an element body or more on the principal surface of a
first organic substrate in which a conductive pattern or patterns
is or are formed, a step of connecting a second organic substrate,
in which a recessed portion is formed in correspondence with the
area where the element body or bodies is or are mounted at a
connecting surface to the first organic substrate, to the first
organic substrate in such a manner to seal the element body or
bodies within the element body accommodating space portion so that
the element body accommodating space portion is constituted as a
space portion in which moisture resistance characteristic and
oxidation resistance characteristic are maintained, a step of
forming an insulating resin layer onto the entire surface of at
least one second principal surface of the first organic substrate
and the second organic substrate of the side opposite to a surface
where the first organic substrate and the second organic substrate
are connected to each other, and a step of implementing polishing
processing to the insulating resin layer to allow the second
principal surface to be a planarized (flattened) build-up formation
surface; and a step of forming a high frequency circuit portion via
a step of forming one build-up wiring layer or more in which a
conductive pattern or patterns is or are formed on a dielectric
insulating layer formed at the build-up formation surface of the
base substrate portion, and at least one kind of passive element or
elements is or are formed by the thin film technology or the thick
film technology, the build-up wiring layer being via-connected to
the conductive pattern or patterns and/or the element body or
bodies of the first organic substrate, and a step of mounting high
frequency circuit components (parts) onto the build-up wiring layer
of the uppermost layer.
23. The method of manufacturing high frequency module as set forth
in claim 22, wherein, at the step of manufacturing the base
substrate portion, the connecting step of the first organic
substrate and the second organic substrate is performed within
inactive gas atmosphere.
24. The method of manufacturing high frequency module as set forth
in claim 22, wherein there is used the first organic substrate or
the second organic substrate in which an air vent hole
communicating with the element body accommodating space portion is
formed, and, at the step of manufacturing the base substrate
portion, as steps subsequent to the connecting step of the first
organic substrate and the second organic substrate, a step of
deflating air within the element body accommodating space portion
through the air vent hole, a step of filling inactive gas into the
element body accommodating space portion through the air vent hole,
and a step of closing the air vent hole are implemented to
hermetically introduce or fill inactive gas within the element body
accommodating space portion.
25. The method of manufacturing high frequency module as set forth
in claim 22, wherein the connecting step of the first organic
substrate and the second organic substrate consists of a step of
sticking adhesive sheet to either one connecting surface of the
first organic substrate and the second organic substrate, a step of
combining the first organic substrate and the second organic
substrate after undergone positioning, and a step of allowing the
first organic substrate and the second organic substrate to be in
pressure contact with each other.
26. The method of manufacturing high frequency module as set forth
in claim 22, wherein the connecting step of the first organic
substrate and the second organic substrate consists of a step of
combining the first organic substrate and the second organic
substrate after positioning, and a step of applying ultrasonic wave
to a connecting surface of the first organic substrate and the
second organic substrate to weld it.
27. The method of manufacturing high frequency module as set forth
in claim 22, wherein the step of forming the build-up wiring layer
is adapted so that a first wiring layer is formed via a step of
forming photosensitive dielectric layer onto the entire surface of
the build-up formation surface of the base substrate portion, a via
formation step and a step of forming a conductive pattern or
patterns onto the photosensitive dielectric layer, and wiring
layers of upper layers are formed in succession via similar steps
onto the first wiring layer, and a step of forming solder resist
layer and an electrode formation step are implemented to the wiring
layer of the uppermost layer to mount high frequency circuit
components (parts).
Description
[0001] The subject matter of application Ser. No. 10/519,765 is
incorporated herein by reference. The present application is a
divisional of U.S. application Ser. No. 10/519,765, filed Dec. 28,
2004, which is a 371 National Stage of PCT patent application No.
PCT/JP03/07827, filed Jun. 19, 2003, which claims priority to
Japanese Patent Application No. JP 2002-195022, filed Jul. 3, 2002.
The present application claims priority to these previously filed
applications.
TECHNICAL FIELD
[0002] The present invention relates to a module board device and a
high frequency module suitable when used in wireless communication
modules which are provided at various electronic equipments having
wireless communication function such as personal computers, audio
equipments, various mobile equipments and/or mobile telephones and
permit compatibility at different frequency bands, and a method of
manufacturing these module units.
BACKGROUND ART
[0003] Various information, e.g., music, speech and/or image, etc.
have been permitted to be easily handled also by personal computer
or mobile computer, etc. with digitization of data in recent years.
Moreover, band-compression of these information has been realized
by audio (speech) codec technology or image codec technology so
that the environment where these information are easily and
efficiently distributed (delivered) to various communication
terminal equipments by digital communication or digital broadcast
is being arranged. For example, audio/video data (AV data), etc.
can be received at the indoor/outdoor by wireless system through
mobile telephone, etc. without limitation only to reception by wire
system
[0004] Meanwhile, with respect to the transmission/reception system
for data, etc., suitable network systems have been constructed also
within home and/or small area, and have been variously utilized. As
the network system, attention is drawn to the various next
generation wireless systems, e.g., narrow-band wireless
communication system of 5 GHz band proposed in the IEEE802.11a,
wireless LAN system of 2.45 GHz band proposed in the IEEE802.11b,
and/or near distance wireless communication system called
Bluetooth, etc. In the transmission/reception system for data, etc.
such various wireless network systems are effectively utilized so
that transmission/reception of various data, access to the Internet
and/or transmission/reception of data can be made easily and
without intervention of relay board, etc. at various places such as
home or outdoors, etc.
[0005] In the wireless network systems, respective communication
terminal equipments are permitted to be connected with respect to
all communication systems so that effective utilization can be
realized. Such wireless network systems not only lead to
enlargement and/or high cost of communication terminal equipments,
but also result in large burden also with respect to the
communication infrastructure side. Communication terminal
equipments are utilized not only at indoor but also at outdoor,
etc., and are indispensable that they are compact and light in
weight and are portable, and are inexpensive. For this reason, it
is extremely difficult to constitute the communication terminal
equipments so that they are adapted to the specification of such
wireless network system.
[0006] In the communication terminal equipments, there is being
made development of the so-called Software Defined Radio technology
in which compliance is made by base-band processing below
modulation/demodulation processing with respect to respective
communication systems and/or frequency bands to thereby constitute
wireless communication units as integral unit. However, even such
SDR technology has vast calculation quantity for signal processing.
As a result, even if compliance of burden at the communication
infrastructure side can be realized, compliance of power
consumption at the communication terminal equipment side and/or
compliance of enlargement by integration are great problems.
Particularly, it is difficult that portable communication terminal
equipments are put to practical use.
[0007] A wireless communication module 100 shown in FIGS. 1 and 2
constitutes an analog front end of a wireless transmitter/receiver,
wherein there is realized the so-called multi-band configuration in
which base band portion is shared with respect to the same
modulation/demodulation system or different modulation/demodulation
system, and plural transmitting/receiving units are included
(provided) to permit transmission/reception of wireless signals of
different frequency bands. The wireless communication module 100
transmits or receives wireless signals of different frequency bands
at an antenna unit 101.
[0008] The wireless communication module 100 comprises, as shown in
FIG. 1, although the detail is omitted, a receive signal processing
system 107 adapted for converting a high frequency signal received
at the antenna unit 101 into an intermediate frequency signal on
the basis of reference frequency delivered from a reference
frequency generating circuit unit 103 at a RF-IF converting unit
102 to amplify the intermediate frequency signal thus obtained at
an amplifier unit 104 thereafter to demodulate the intermediate
frequency signal thus amplified at a demodulation unit 105 to
output the signal thus obtained to baseband units 106. The wireless
communication module 100 comprises, although the detail is omitted,
a transmit signal processing system 110 for directly converting the
intermediate frequency signal outputted from the baseband unit 106
into high frequency signal at an IF-RF converting unit 108 and
demodulating that intermediate frequency signal to transmit the
signal thus obtained from the antenna unit 101 through an amplifier
unit 109.
[0009] Although the detail is omitted, the wireless communication
module 100 is adapted so that large functional components (parts)
such as various filters, Voltage Controlled Oscillator (VCO) and
Surface Acoustic Wave (SAW) device, etc. are mounted between
respective stages, and includes passive elements such as inductors,
capacitors and/or resistors, etc. which are specific to high
frequency analog circuit. At the wireless communication module 100,
as shown in FIG. 1, first to third changeover switches 111 to 113
are provided at RF-IF converting unit 102, reference frequency
generating circuit unit 103 or demodulation unit 105 of the receive
signal processing system 107. Moreover, at the wireless
communication module 100, fourth and five changeover switches 114
and 115 are provided also at IF-RF converting unit 108 or amplifier
unit 109 within the transmit signal processing system 110.
[0010] Although the detail is omitted, the first to third
changeover switches 111 to 113 are caused to undergo switching
operation to perform capacity switching of variable capacitors
and/or variable reactances to thereby perform control of time
constant switching so as to match the frequency characteristic of
receive signal. Although the detail is omitted, the fourth and five
changeover switches 114 and 115 are also caused to undergo
switching operation to thereby perform capacity switching of
variable capacitors and/or variable reactances to perform control
of time constant switching so as to match frequency characteristic
of transmit signal.
[0011] The wireless communication module 100 comprises, as shown in
FIG. 2, a module board (substrate) 120 comprised of multi-layered
wiring board, and is constituted, although the detail is omitted,
as the result of the fact that passive elements and/or capacity
patterns, etc. constituting the above-described respective
functional blocks are formed together with wiring patterns within
respective wiring layers of the module board 120. At the module
board 120, a high frequency signal processing LSI 121 and suitable
chip components (parts) 122 are mounted on the surface thereof, and
a shield cover 123 is assembled for the purpose of excluding the
influence. of electromagnetic noise. It is to be noted that, at the
module board 120, antenna pattern constituting the antenna unit 101
may be formed at, e.g., a portion which is not covered by the
shield cover 123 of the surface. In addition, at the module board
120, antenna unit 101 may be constituted by chip-type antenna
mounted on the surface, or transmit/receive signal may be inputted
or outputted from the antenna of separate member.
[0012] At the wireless communication module 100, as shown in FIG.
2, the above-described first to five changeover switches 111 to 115
are constituted by MEMS (Micro Electro Mechanical System) switches
130 mounted on the surface of the module board 120. As shown in
FIG. 3, the entirety of the MEMS switch 130 is covered by an
insulating cover 131. The MEMS switch 130 is mounted on module
wiring board 120 as described above through leads 132 drawn from
the insulating cover 131.
[0013] As shown in FIG. 3, the MEMS switch 130 is adapted so that a
first fixed contact 134, a second fixed contact 135 and a third
fixed contact 136 are formed on a silicon substrate 133, and a
movable contact piece 137 in a thin plate form and having
flexibility is fixed at the first fixed contact 134 and the free
end thereof is cantilever-supported in a manner opposed to the
third fixed contact 136. The MEMS switches 130 are respectively
connected to leads 132 through wires 138 in the state where the
first and third fixed contacts 134 and 136 are used as output
contact. Additionally, the second fixed contact 136 is also
connected to other lead 132. At the movable contact piece 137, an
electrode 139 is provided at the portion opposite to the second
fixed contact 135.
[0014] At the MEMS switch 130, as shown in FIG. 3, a silicon cover
140 is connected onto the silicon base 133 by, e.g., anode
connecting method, etc. to allow the first to third fixed contacts
134 to 136 and the movable contact piece 137 to be maintained in
the air-tight state. The entirety of the MEMS switch 130 is sealed
by the insulating cover 131 so that the MEMS switch 130 is
integrated as package. At the MEMS switch 130, as the result of the
fact that the movable portion thereof is sealed by the silicon
substrate 133 and the silicon cover 140 and the entirety thereof is
sealed by the insulating cover 131, moisture resistance
characteristic and oxidation resistance characteristic are
maintained, and durability with respect to the mechanical load from
the external is maintained.
[0015] At the MEMS switch 130 constituted as described above, when
drive voltage is applied, the third fixed contact 136 and the
movable contact piece 137 are shorted by electromagnetic attractive
force produced between the second fixed contact 135 and the
electrode 139 of the movable contact piece 137, and the short state
thereof is maintained. At the MEMS switch 130, when reverse bias
drive voltage is applied, the movable contact piece 137 is returned
to the initial state by electromagnetic repulsive force produced
between the second fixed contact 135 and the electrode 139 so that
the short state with respect to the third fixed contact 136 is
released. Since the MEMS switch 130 is a switch element which is
extremely very small and does not require holding current for
holding the operating state, it is possible to suppress enlargement
of the wireless communication module 100 and to realize low power
consumption.
[0016] The wireless communication module 100 as described above is
caused to be of the configuration in which switching of time
constant is performed by the MEMS switches 130 to thereby switch
the frequency characteristics of the antenna, respective filters
and/or VCO, etc. so that there results tunable state. Meanwhile,
since the MEMS switch 130 has movable portion, first to third fixed
contacts 134 to 136 and/or wiring patterns are finely formed on the
silicon substrate 133 as described above, and the silicon base 133
and the silicon cover 140 are connected by the anode connecting
method, etc. thereafter to cover it by the insulating cover 131 so
that the MEMS switch 130 is caused to be of package configuration.
Thus, MEMS switches 130 are mounted on the module board similarly
to other mounting components (parts).
[0017] In the above-described conventional wireless communication
module 100, there is the problem that the characteristic is lowered
by the influence on the high frequency circuit unit resulting from
reflection or loss from parasitic component of the MEMS switch 130.
In the wireless communication module 100, there is the problem that
MEMS switches are mounted on the surface of the module board 120 so
that path lengths between the MEMS switches 130 and internal
circuits are elongated, whereby the characteristic is lowered by
the influence of the interference or loss. Further, in the wireless
communication module 100, since the MEMS switch 130 has the
structure that respective components are assembled on the silicon
substrate 133 and are sealed by the insulating cover 131 so that
they are packaged, further miniaturization is difficult.
[0018] In the above-described conventional wireless communication
module 100, e.g., SAW device (Surface Acoustic Wave Device), and/or
IC and LSI for micro-wave or mili-wave, etc. are also mounted.
There is the problem that in the case where these elements are
coated by insulating resin, their characteristics are remarkably
deteriorated.
DISCLOSURE OF THE INVENTION
[0019] An object of the present invention is to provide a novel
module board device and a method of manufacturing the same, which
can solve problems that conventional wireless communication modules
have.
[0020] Another object of the present invention is to provide a
module board device and a method of manufacturing the same, which
does not require package structure of elements to realize
improvement in reliability along with miniaturization and low
cost.
[0021] A further object of the present invention is to provide a
high frequency module having multi-band compliance function, which
comprises MEMS switches which permit compatibility at different
frequency bands and/or elements of which characteristics are
deteriorated by resin sealing, and which realizes improvement in
the characteristics and reliability of these elements and realizes
miniaturization and low cost, and a method of manufacturing such a
high frequency module.
[0022] A board device for module according to the present invention
comprises a first organic substrate in which a conductive pattern
or patterns is or are formed on the principal surface thereof and
one element body is or more are mounted, and a second organic
substrate in which a recessed portion is formed in correspondence
with the area where the element body or bodies is or are formed at
a connecting surface to the first organic base. At the module board
device, an element accommodating space portion which seals the
element body or bodies is constituted by the recessed portion in
the state where the second organic base is connected to the first
organic base. At the module board device, the element body
accommodating space portion is constituted as a space portion in
which moisture resistance characteristic and oxidation resistance
characteristic are maintained.
[0023] At the module board device, since element body or bodies are
constituted at the inside of wiring layer, and element body or
bodies are directly formed at the element body accommodating space
portion in which moisture resistance characteristic and oxidation
resistance characteristic are maintained, package for maintaining
moisture resistance characteristic and/or oxidation resistance
characteristic, and/or for preventing the element body or bodies
from mechanical load from the external is not required at the
element body. As a result, miniaturization thereof can be realized
and path lengths with respect to the wiring layer are shortened.
Thus, low loss and improvement in noise resistance characteristic
can be realized. At the module board device, aging deterioration
(deterioration with lapse of time) of the element body is
maintained in a manner equivalent to the packaged state so that
stable operation is performed, and occurrence of inconvenience such
as damage, etc. of package by evaporation of moisture immersed into
the inside in reflow soldering, etc. is also prevented. At the
module board device, MEMS switch which can change capacitance
characteristic of antenna or filter with respect to different
frequency bands is used as the element body, thereby making it
possible to obtain compact and thin type, and high reliability high
frequency module which has realized multi-band compliance
function.
[0024] A method of manufacturing a board device for module
according to the present invention includes a step of mounting one
element body or more on the principal surface of a first organic
substrate in which a conductive pattern or patterns is or are
formed, and a step of connecting a second organic substrate, in
which a recessed portion is formed in correspondence with the area
where the element body or bodies is or are formed at a connecting
surface to the first organic substrate, to the first organic
substrate in such a manner to seal the element body or bodies
within an element accommodating space portion constituted by the
recessed portion, thus to manufacture a module board device
including the element body accommodating space portion in which
moisture resistance characteristic or oxidation resistance
characteristic are maintained.
[0025] In the manufacturing method for board device for module
according to the present invention, since element body or bodies
are constituted at the inside of the wiring layer, and element body
or bodies are directly formed at element body accommodating space
portion constituted in which moisture resistance characteristic and
oxidation resistance characteristic are maintained, package for
maintaining moisture resistance characteristic or oxidation
resistance characteristic, and/or for protecting the element body
from mechanical load from the outside is not required at the
element body. As a result, miniaturization thereof is realized and
path lengths with respect to the wiring layers are shortened. Thus,
module board device in which low loss and improvement in noise
resistance characteristic have been realized is manufactured. In
accordance with the manufacturing method for board device for
module, it becomes possible to efficiently manufacture, in the
state where occurrence of inconvenience such as damage, etc. of
package by evaporation of moisture immersed into the inside in
reflow soldering, etc. is prevented, module board device in which
aging deterioration of element body is maintained in a manner
equivalent to the packaged state so that stable operation is
performed.
[0026] The high frequency module according to the present invention
is composed of a base substrate portion, and a high frequency
circuit portion which is built up on the principal surface of the
base substrate portion. The base substrate portion comprises a
first organic substrate in which a conductive pattern or patterns
is or are formed on the principal surface thereof and an element
body or bodies is or are mounted, and a second organic substrate in
which a recessed portion is formed in correspondence with the area
where the element body or bodies is or are formed at a connecting
surface to the first organic substrate, whereby, in the state where
the first organic substrate and the second organic substrate are
connected, an element body accommodating space portion which seals
the element body or bodies is constituted by the recessed portion,
and the element body accommodating space portion is caused to have
moisture resistance characteristic and oxidation resistance
characteristic and a second principal surface opposite to the
connecting surface of either one of the first organic substrate and
the second organic substrate is caused to undergo planarization
(flattening) processing to constitute build-up formation surface.
The high frequency circuit portion comprises one build-up wiring
layer or more in which a conductive pattern or patterns is or are
formed on a dielectric insulating layer at the build-up formation
surface of the base substrate portion, and including at least one
kind of passive element or more formed by the thin film technology
or the thick film technology, the build-up wiring layer being
via-connected to the base substrate portion and/or the element body
or bodies, and high frequency circuit components (parts) mounted on
the build-up wiring layer of the uppermost layer.
[0027] At the high frequency module according to the present
invention, since, e.g., MEMS switch or switches which can change
capacity characteristic of antenna or filter to realize multi-band
function, and/or element body or bodies of which characteristics
are deteriorated by resin coating, etc. are constituted within the
wiring layer of the base substrate portion, and are directly formed
at element body accommodating space portion in which moisture
resistance characteristic and/or oxidation resistance
characteristic are maintained, package for maintaining moisture
resistance characteristic and/or oxidation resistance
characteristic and for protecting the element body from mechanical
load from the external becomes is not required at the element body.
As a result, miniaturization thereof can be realized and path
lengths with respect to the wiring layers are shortened. Thus, low
loss and improvement in noise resistance characteristic can be
realized. At the high frequency module, aging deterioration of the
element body is maintained in a manner equivalent to the packaged
state so that suitable operation is performed, and occurrence of
inconvenience such as damage, etc. of package by evaporation of
moisture immersed into the inside in reflow soldering, etc. is also
prevented. Further, at the high frequency module, high frequency
circuit portion in which various passive elements are formed on
planarized (flattened) buildup formation surface of the base
substrate portion including relative inexpensive organic substrate
is formed with high accuracy so that reduction of cost can be
realized, and the base substrate portion is constituted as, e.g.,
wiring portions for power supply and/or ground portion, and/or
wiring portion for the control system. Thus, electrical isolation
from the high frequency circuit portion can be realized. In
accordance with the high frequency module, occurrence of electric
interference of the high frequency circuit portion is suppressed so
that improvement in the characteristic is realized. Since wirings
for power supply and/or ground portion having sufficient area can
be formed on the base substrate portion, power supply of high
regulation is performed.
[0028] The method of manufacturing a high frequency module
according to the present invention includes a formation step for
high frequency circuit portion for build-up forming the high
frequency circuit portion on a planarized (flattened) build-up
formation surface via a step of manufacturing a base substrate
portion. In the manufacturing method for high frequency module, the
step of manufacturing the base substrate includes a step of
mounting an element body or bodies on the principal surface of a
first organic substrate in which a conductive pattern or patterns
is or are formed, a step of connecting a second organic substrate,
in which a recessed portion is formed in correspondence with the
area where the element body or bodies is or are formed at a
connecting surface to the first organic substrate, to the first
organic substrate in such a manner to seal the element body or
bodies into the element body accommodating space portion
constituted by the recessed portion and for constituting the
element body accommodating space portion as a space portion in
which moisture resistance characteristic and/or oxidation
resistance characteristic are maintained, and a step of
implementing planarization (flattening) processing to a second
principal surface opposite to the connecting surface of either one
of the first organic substrate and the second organic substrate to
form a build-up formation surface, thus to form a base substrate
portion where inactive gas is sealed within the element body
accommodating space portion. In the manufacturing method for high
frequency module, the step of forming the high frequency circuit
portion includes a step of forming one build-up wiring layer or
more in which a conductive pattern or patterns is or are formed on
a dielectric insulating layer, and at least one kind of passive
element or more is or are formed by the thin film technology or the
thick film technology, the build-up wiring layer being
via-connected to the conductive pattern or patterns and/or the
element body or bodies of the first organic substrate of the base
substrate portion, and a step of mounting high frequency circuit
components (parts) on the build-up wiring layer of the uppermost
layer, thus to form high frequency circuit portion on the build-up
formation surface of the base substrate portion.
[0029] In the manufacturing method for high frequency module
according to the present invention, since element body or bodies
are constituted within the wiring layer of the base substrate
portion, and are directly formed within the element body
accommodating space portion in which moisture resistance
characteristic and/or oxidation resistance characteristic are
maintained, package for maintaining moisture resistance
characteristic and/or oxidation resistance characteristic, and/or
for protecting the element body or bodies from mechanical load from
the external is not required at the element body. As a result,
miniaturization thereof can be realized and path lengths with
respect to the wiring layers are shortened. Thus, high frequency
module in which low loss and improvement in noise resistance
characteristic have been realized is manufactured. In the
manufacturing method for high frequency module, aging deterioration
of the element body is maintained in a manner equivalent to the
packaged state so that stable operation is performed, and
occurrence of inconvenience such as damage, etc. of package
resulting from evaporation of moisture immersed into the inside in
reflow soldering, etc. is also prevented so that manufacturing of
high frequency module is performed. Further, in the manufacturing
method for high frequency module, as the result of the fact that
high frequency circuit portion in which various passive elements
are formed on planarized (flattened) build-up formation surface of
the base substrate portion including relatively inexpensive organic
substrate is formed with high accuracy, reduction of the cost can
be realized, and the base substrate portion is constituted as,
e.g., wiring portions for power supply and/or ground portion,
and/or wiring portion for the control system so that high frequency
module in which electrical isolation from the high frequency
circuit portion has been realized is manufactured. In accordance
with the manufacturing method for high frequency module, since
occurrence of electrical interference of the high frequency circuit
portion is suppressed so that the characteristic has been improved,
and wirings for the power supply and/or the ground portion having
sufficient area can be formed on the base substrate portion, high
frequency module in which power supply of high regulation is
performed is manufactured.
[0030] Still further objects of the present invention and practical
merits obtained by the present invention will become more apparent
from the description of the embodiments which will be given below
with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a block diagram showing a circuit configuration of
a wireless communication module in which multi-band configuration
has been realized.
[0032] FIG. 2 is an essential part longitudinal cross sectional
view showing a conventional wireless communication module.
[0033] FIG. 3 is a longitudinal cross sectional view showing MEMS
switch package used in the conventional wireless communication
module.
[0034] FIG. 4 is an essential part longitudinal sectional view
showing a high frequency module according to the present
invention.
[0035] FIG. 5 is a longitudinal cross sectional view showing
double-sided substrate used in the high frequency module according
to the present invention.
[0036] FIG. 6 is a longitudinal cross sectional view showing a step
of mounting MEMS switch on the double-sided substrate.
[0037] FIG. 7 is an essential part side view showing MEMS switch
used in the high frequency module.
[0038] FIG. 8 is a longitudinal cross sectional view showing a step
of connecting organic insulating block body to the double-sided
substrate.
[0039] FIG. 9 is a longitudinal cross sectional view showing steps
for wiring pattern and through-hole formed at organic insulating
block body.
[0040] FIG. 10 is a longitudinal cross sectional view showing a
step of planarizing (flattening) build-up formation surface of base
substrate portion.
[0041] FIG. 11 is a longitudinal cross sectional view showing a
step of forming first dielectric insulating layer of high frequency
circuit portion.
[0042] FIG. 12 is a longitudinal cross sectional view showing a
step of forming first wiring layer of the high frequency circuit
portion.
[0043] FIG. 13 is a longitudinal cross sectional view showing a
step of forming capacitor elements and resistor elements at the
first wiring layer.
[0044] FIG. 14 is a longitudinal cross sectional view showing a
step of forming second dielectric insulating layer of the high
frequency circuit portion.
[0045] FIG. 15 is a longitudinal cross sectional view showing a
step of forming second wiring layer and inductor element of the
high frequency circuit portion.
[0046] FIG. 16 is a longitudinal cross sectional view showing a
step of forming protective layers at base substrate portion and the
high frequency circuit portion.
[0047] FIG. 17 is a longitudinal cross sectional view showing a
step of forming electrodes at base substrate portion and high
frequency circuit portion.
[0048] FIG. 18 is an essential part longitudinal cross sectional
view of high frequency module in which MEMS switch is mounted by
wire-bonding method.
[0049] FIG. 19 is a longitudinal cross sectional view showing
another example of high frequency module according to the present
invention.
[0050] FIG. 20 is a longitudinal cross sectional view showing
double-sided substrate used in the high frequency module.
[0051] FIG. 21 is a longitudinal cross sectional view showing a
step of forming shield layer at doubled-sided substrate.
[0052] FIG. 22 is a longitudinal cross sectional view showing a
step of forming an opening portion for connection at shield
layer.
[0053] FIG. 23 is a longitudinal cross sectional view showing a
step of mounting MEMS switch at the double-sided substrate.
[0054] FIG. 24 is a longitudinal cross sectional view showing a
step of connecting organic insulating block body to the
double-sided substrate.
[0055] FIG. 25 is a longitudinal cross sectional view showing a
further example of the high frequency module according to the
present invention.
[0056] FIG. 26 is a longitudinal cross sectional view showing the
configuration of base substrate portion, and shows the connecting
state between double-sided substrate and organic insulating block
body.
[0057] FIG. 27 is an essential part longitudinal cross sectional
view showing the configuration of the base substrate portion, and
shows the state where ventilation hole is closed.
BEST MODE FOR CARRYING OUT THE INVENTION
[0058] Embodiments of the present invention will now be described
in detail with reference to the attached drawings.
[0059] First, a high frequency module to which the present
invention has been applied will be explained. The high frequency
module is used in various electronic equipments having wireless
communication function, e.g., personal computers, audio equipments,
various mobile equipments and/or mobile telephones, etc. and
constitutes analog front end of the wireless transmitting/receiving
unit.
[0060] As shown in FIG. 4, the high frequency module 1 according to
the present invention is caused to be of the so-called multi-band
configuration in which the base band portion is shared with respect
to the same modulation/demodulation system or the different
modulation/demodulation systems, and transmission/reception of
wireless signals of different frequency bands can be made. Although
the detail will be described later, the high frequency module 1 is
composed of a base substrate portion 2 formed by base substrate
portion manufacturing process, and a high frequency circuit portion
4 which is build-up formed by high frequency circuit portion
manufacturing process on a build-up formation surface 3 constituted
by planarizing (flattening) the first principal surface of the base
substrate portion 2.
[0061] The high frequency module 1 comprises, although the detailed
explanation is omitted, circuit units for receive signal processing
system and transmit signal processing system, and has the function
equivalent to the above-described conventional wireless
communication module 100. In the high frequency module 1, the base
substrate portion 2 constitutes the mounting surface with respect
to wiring portions for the power supply system and or the control
system with respect to the high frequency circuit portion 4, or
interposer (not shown). In the high frequency module 1, high
frequency ICs 5 and chip components (parts) 6 are mounted with the
uppermost layer surface of the high frequency circuit portion 4
being as a mounting surface, and shield cover (not shown) is
assembled so that the entirety of the surface is sealed.
[0062] At the high frequency module 1, MEMS switches 7 are mounted
(assembled) in the state where they are sealed within the base
substrate portion 2. By performing switching operation of the MEMS
switches 7, capacity switching operations. of variable capacitor
and variable reactance of the receive signal processing system or
the transmit signal processing system are performed to perform
control of switching of time constant so as to match frequency
characteristics of receive signal and/or transmit signal. In the
high frequency module 1, at high frequency circuit portion
formation process which will be described later, capacitor elements
8, resistor elements 9 and/or inductor elements 10 are formed as
film along with wiring layers within the high frequency circuit
portion 4.
[0063] The base substrate portion 2 is formed after experiencing a
MEMS switch mounting step of mounting, with a double-sided
substrate 11 serving as a first organic substrate being as a base
substrate, MEMS switches 7 on the double-sided substrate 11, a
connecting step of connecting an organic insulating block body 12
serving as a second organic substrate to the double-sided substrate
11, a wiring formation step of forming wiring patterns 12a or vias
12b at the organic insulating block body 12, and a planarization
(flattening) step of planarizing (flattening) the surface of the
organic insulating block body 12 to form build-up formation surface
3, etc. At the double-sided substrate 11, as shown in FIG. 5,
wiring patterns 11b, 11c are formed on the face principal surface
and the back principal surface of the organic substrate 11a, and
these wiring patterns 11b, 11c are connected through through-holes
11d.
[0064] At the double-sided substrate 11, the organic substrate 11a
is molded by thermoplastic synthetic resin having low dielectric
constant and low Tan .delta. characteristic, i.e., satisfactory
high frequency characteristic, and excellent in heat resistance
characteristic, chemical resistance characteristic, moisture
resistance characteristic and/or sealing resistance characteristic,
e.g., polyolefine resin, liquid crystal polymer (LCP) or polyphenyl
ethylene (PPE), etc. Wiring pattern formation method conventionally
used, e.g., additive method, etc. is implemented to the
double-sided substrate 11 so that wiring patterns 11b, 11c are
formed and through-holes 11d are formed at the face principal
surface and the back principal surface of the organic substrate 11a
as shown in FIG. 5. Patterning by plating resist is performed onto
the face principal surface and the back principal surface of the
organic substrate 11a where penetration holes are formed in advance
to form conductive patterns by electroless copper plating
thereafter to remove plating resist. Thus, the double-sided
substrate 11 is formed.
[0065] It is to be noted that the double-sided substrate 11 may be
also formed by, e.g., semi-additive method, and may be also formed
by subtractive method by using copper-clad substrate. With respect
to the organic substrate 11a, as described later, moisture
resistance processing and or sealing processing may be implemented
so that there may be used not only the above-described substrate
materials, but also base material consisting of phenol resin,
bismaleimide triazine (BT-resin), polyimide,
polytetrafluoroetyylene, polynorbornane (PNB), glass epoxy, ceramic
or mixture of ceramic and organic material, etc.
[0066] At the double-sided substrate 11, the first wiring pattern
11b constitutes power supply circuit portion and or ground portion,
etc., and the second wiring pattern 11c constitutes mounting
portion onto the interposer, etc. At the double-sided substrate 11,
as the detail will be described later, a protective layer 13
consisting of solder resist which covers or coats the second wiring
pattern 11c is formed, and an input/output terminal electrode 14 is
formed.
[0067] MEMS switch mounting process by, e.g., flip-chip method is
implemented to the double-sided substrate 11. As shown in FIG. 6,
MEMS switch 7 is mounted at a predetermined position of the first
wiring pattern 11b. While the fundamental configuration of the MEMS
switch 7 is caused to be the same as the above-described MEMS
switch package 130, the MEMS switch 7 is used in the so-called bare
state where insulating cover 131 and/or silicon cover 140 are not
included (provided) as shown in FIG. 7. Accordingly, the MEMS
switch 7 is caused to be of the configuration in which the entirety
thereof is thin as compared to the MEMS switch package 130.
[0068] At the MEMS switch 7, as shown in FIG. 7, a first fixed
contact 16, a second fixed contact 17 and a third fixed contact 18
are formed on a silicon substrate 15, and a movable contact piece
19 in a thin-plate form and having flexibility is
cantilever-supported with respect to the first fixed contact 16. At
the MEMS switch 7, connection pads 16a, 18a are respectively formed
in a manner integral with the first fixed contact 16 and the third
fixed contact 18 on the silicon substrate 15. At the MEMS switch 7,
the free end of the movable contact piece 19 is opposed to the
third fixed contact 18, and an electrode 20 is provided at the
position opposite to the second fixed contact 17.
[0069] At the MEMS switch mounting process, as indicated by chain
line in FIG. 7, gold ball bumps 21 are respectively formed on
connection pads 16a, 18a of the first and third fixed contacts 16
and 18 of the MEMS switch 7. At the MEMS switch mounting process,
although the detail is omitted, nickel-gold plating is implemented
onto the connection pads formed at the first wiring pattern 11b of
the double-sided substrate 11 to form electrodes. In this example,
the electrode is formed so that the thickness of the nickel layer
is 4.mu. to 5 .mu.m, and the thickness of the gold layer is 0.3
.mu.m or more.
[0070] At the MEMS switch mounting process, the MEMS switches 7 are
mounted with respect to the double-sided substrate 11 after
undergone positioning in the state where the silicon substrate 15
is caused to be at the upper side so that opposite spacing is
maintained by the gold ball bumps 21. At the MEMS switch mounting
process, e.g., ultrasonic wave is applied while applying pressure
to the gold ball bumps 21 so that it has about several ten grams in
the state where the double-sided substrate 11 is heated so that its
temperature is about 80.degree. C. to 120.degree. C. to thereby
mount MEMS switches 7 on the double-sided substrate 11. It is to be
noted that the MEMS switch mounting process is not limited to such
ultrasonic wave flip-chip mounting method, but MEMS switches 7 may
be mounted on the double-sided substrate 11 by suitable bare chip
mounting method.
[0071] At the double-sided substrate 11, there is implemented
connecting process for connecting organic insulating block body 12
onto the principal surface where MEMS switches 7 are mounted. The
organic insulating block body 12 is also molded by thermoplastic
synthetic resin having low dielectric constant and low Tan .delta.
characteristic, i.e., satisfactory high frequency characteristic,
and excellent in heat resistance characteristic, chemicals
resistance characteristic or moisture resistance characteristic,
e.g., polyolefine resin, liquid crystal polymer (LCP) or polyphenyl
ethylene (PPE), etc. Moreover, as material of the organic
insulating block body 12, there may be also used, e.g., phenol
resin, bismaleimide triazine (BT-resin), polyimide,
polytetrafloroethylene, polynorbornane (PNB), glass epoxy, ceramic
or mixture of ceramic and organic material, etc. The organic
insulating block body 12 is formed as a rectangular block body
having outer appearance sufficient to cover the entire surface of
the double-sided substrate 11 and thickness slightly larger than
height of the MEMS switch 7.
[0072] At the organic insulating block body 12, as shown in FIG. 8,
a recessed portion 22 having opening shape sufficient to cover MEMS
switch 7 is formed at the connecting portion to the double-sided
substrate 11. As the result of the fact that metallic shield layer
23 is formed as film at the internal surface of the recessed
portion, the recessed portion 22 is constituted so that moisture
resistance characteristic and/or sealing characteristic are
maintained in the state where the MEMS switch is covered as
described later. The metallic shield layer 23 is formed as film by,
e.g., the MID method (Molded Interconnect Device) of
three-dimensionally forming electric circuits with respect to resin
molded body by plating, etc. The metallic shield layer 23 may be
formed as film by the deposition process.
[0073] At the connection process, the double-sided substrate 11 and
the organic insulating block body 12 which have been described
above are delivered to inactive gas atmosphere, e.g., nitric box,
etc. to implement, e.g., ultrasonic wave welding method, etc. in
the state where the organic insulating block body 12 is caused to
overlap with the double-sided substrate 11 after undergone
positioning as shown in FIG. 8 to integrate them. The double-sided
substrate 11 and the organic insulating block body 12 seal MEMS
switches 7 within the MEMS switch accommodating space portion 24
constituted by recessed portion 22 in the connected state.
[0074] At the connecting step, since the double-sided substrate 11
and the organic insulating block body 12 are connected within the
nitric box as described above, nitric gas is sealed into the MEMS
switch accommodating space portion 24. Accordingly, the MEMS
switches 7 are mounted within the MEMS switch accommodating space
portion 24 in the state where moisture resistance characteristic
and oxidation resistance characteristic are maintained. From this
fact, oxidation of respective components and/or sticking of movable
contact piece 19, etc. are prevented. Thus, improvement in
durability and operating stability can be realized. In addition,
since the MEMS switches 7 are caused to undergo so-called bare
mounting, miniaturization and thin structure of the high frequency
module 1 can be realized, and the MEMS switches 7 are protected
also with respect to mechanical load from the outside, etc.
[0075] Since the high frequency module 1 has excellent moisture
resistance characteristic in such a manner that moisture is
prevented from being immersed into the MEMS switch accommodating
space portion 24, it is possible to prevent such an accident that
moisture immersed at the time of reflow soldering process is
evaporated as described later so that the MEMS switch accommodating
portion is burst. At the high frequency module 1, since metallic
shield layer 23 is formed at the internal surface of the recessed
portion 22 so that the MEMS switch accommodating space portion 24
is constituted as electromagnetic shield space portion. As a
result, influence of electromagnetic noise on the MEMS switches 7
is reduced. Thus, stable operation can be performed.
[0076] As shown in FIG. 9, wiring formation process is implemented
to the organic insulating block body 12 so that predetermined
wiring patterns 12a are formed on the principal surface 12d and
vias 12b for realizing connection to the first wiring pattern 11b
of the double-sided substrate 11 are formed. At the wiring
formation step, via holes are formed at predetermined positions of
the organic insulating body 12 with the first wiring pattern 11b
being as a stopper by drill method, laser method or plasma method,
etc. to implement desmear processing to the respective via holes.
At the wiring formation step, wiring pattern formation method
generally performed, e.g., additive method or semi-additive method,
etc. is implemented to thereby form wiring patterns 12a on the
principal surface 12d as shown in FIG. 9. In addition, at the
wiring formation step, electrically conductive processing is
implemented into the via holes along with wiring patterns 12a.
Thereafter, cover formation is performed by the plating method.
Thus, vias 12b are formed.
[0077] Planarization (flattening) process is implemented to the
double-sided substrate 11 and the organic insulating block body 12
so that base substrate portion 2 having flat build-up formation
surface 3 is formed as shown in FIG. 10. At the organic insulating
block body 12, wiring patterns 12a are coated so that an insulating
resin layer 25 having a predetermined thickness is formed, and
polishing processing is implemented to the insulating resin layer
25. Also at the double-sided substrate 11, second wiring pattern
11c is coated so that an insulating layer 26 having a predetermined
thickness is formed, and polishing processing is implemented to the
insulating layer 26. For polishing processing, polishing material
consisting of, e.g., mixed liquid of alumina and silica is used.
The insulating resin layer 25 and the insulating resin layer 26 are
polished until the wiring pattern 12a and the second wiring pattern
11c are exposed.
[0078] It should be noted that polishing processing may be
performed in such a manner that the insulating resin layer 26 is
left at a slight thickness without exposing the second wiring
pattern 11c with respect to the double-sided substrate 11 side thus
to protect the second wiring pattern 11c from chemicals or
mechanical or thermal load at high frequency circuit portion
manufacturing step which will be described later. The insulating
resin layer 26 is removed in forming input/output electrodes 14 on
the double-sided substrate 11. With respect to the polishing
processing, the insulating resin layer 25 and the insulating resin
layer 26 are polished by dry etching method, e.g., Reactive Ion
Etching (RIE) or Plasma Etching (PE), etc. so that they are
planarized (flattened).
[0079] While the base substrate portion 2 is manufactured via the
above-described respective process steps with the double-sided base
11 being as base, the manufacturing process is not limited to such
process. A large number of base substrate portions 2 may be
manufactured at the same time on the work of 8 cm or more, for
example. The fundamental process for the base substrate portion 2
is caused to be the conventional manufacturing process for
multi-layer wiring base so that the manufacturing process for
multi-layer wiring board can be also applied. Thus, large scale
plant and equipment investment becomes unnecessary. While the base
substrate portion 2 is manufactured with relatively inexpensive
double-sided base 11 being as base, such base substrate portion 2
may be also manufactured with a suitable base such as. further
inexpensive copper-clad base or substrate to which copper foil with
resin is connected, etc. being as base.
[0080] High frequency circuit portion formation process is
implemented to the base substrate portion 2 which has been
manufactured via the above-described process steps so that high
frequency circuit portion 4 is formed on the build-up formation
surface 3 of the organic insulating block body 12. The high
frequency circuit portion formation process includes a first
dielectric insulating layer formation step, a first metallic thin
film layer formation step, and a first wiring layer formation step.
At the first wiring layer formation step, capacitor element 8 and
resistor element 9 are formed as film as described later. The high
frequency circuit portion formation step includes a second
dielectric insulating layer formation step, a second metallic thin
film layer formation step, a second wiring, layer formation step, a
resist layer formation step, and a parts (components) mounting
step. At the second wiring layer formation step, an inductor
element 10 is formed as film as described later.
[0081] As shown in FIG. 4, the high frequency circuit portion 4 is
comprised of five layer structure of a first dielectric insulating
layer 27, a first wiring layer 28, a second dielectric insulating
layer 29, a second wiring layer 30, and a protective layer 31 for
coating and protecting the second wiring layer 30. At the high
frequency circuit portion formation step, in the case where the
high frequency circuit portion 4 is caused to be of multi-layer
configuration, a necessary number of dielectric insulating layer
formation steps and wiring layer formation steps are repeated.
[0082] At the high frequency circuit portion 4, as shown in FIG. 4,
the first wiring layer 28 is interlayer-connected to the first
wiring pattern 11b of the base substrate portion 2 side through via
32 and via 12b. At the high frequency circuit portion 4, the first
wiring layer 28 and second wiring layer 30 are interlayer-connected
through via 33. At the high frequency circuit portion 4, capacitor
element 8 and resistor element 9 are formed as film within the
first wiring layer 28. At the high frequency circuit portion 4,
inductor element 10 is formed as film within the second wiring
layer 30. In this example, shield cover (not shown) is assembled
onto the surface of the high frequency circuit portion 4 as
occasion demands so that the influence of electromagnetic noise is
excluded.
[0083] Then, the manufacturing process for the high frequency
circuit portion 4 will be explained in detail with reference to
FIGS. 11 to 17. At the first dielectric insulating layer formation
step, insulating dielectric material is coated onto the build-up
formation surface 3 of the base substrate portion 2 to form, as
film, first dielectric insulating layer 27 as shown in FIG. 11. As
the insulating dielectric material, there is used, similarly to the
base substrate 5, organic insulating base material excellent in the
high frequency characteristic, and excellent in heat resistance
characteristic, chemicals resistance characteristic and strong heat
resistance characteristic of at least 160.degree. C. or more. As
the insulating dielectric material, there are used, e.g.,
benzocyclobutene (BCB), polyimide, polynorbornane (PNB), liquid
crystal polymer (LCP), bismaleimide triazine (BT-resin), polyphenyl
ethylene (PPE), epoxy resin and/or acrylic resin. As the film
formation. method, spin-coat method, curtain-coat method, roll-coat
method or dip-coat method in which coating uniformness and
thickness controllability are maintained, etc. are applied.
[0084] At the first dielectric-insulating layer 27, as shown in
FIG. 11, there are formed a large number of via holes 32
communicating with electrode portions formed at the first wiring
pattern 11b of the base substrate portion 2 side. In the case where
photosensitive resin is used as insulating dielectric material,
respective via holes 32 are formed by the photolithographic method
with a mask formed into a predetermined patterning being attached
to the first dielectric insulating layer 27. In the case where
non-photosensitive resin is used as insulating dielectric material,
respective via holes 32 are formed by implementing dry etching
method, e.g., Reactive Chemical Etching, etc. to the first
dielectric insulating layer 27 with, e.g., photo-resist or metallic
film of gold, etc. being as mask.
[0085] At the first metallic thin film formation step, as shown in
FIG. 12, metallic thin film layer 34 of Cu, Al, Pt, Au, etc. is
formed as thin film by, e.g., sputtering method, etc., on the first
dielectric insulating layer 27. At the first metallic thin film
formation process, in order to improve tightness between the first
dielectric insulating layer 27 and the metallic thin film layer 34,
e.g., metallic thin film of Cr, Ni, Ti, etc. may be formed as
barrier layer. The metallic thin film layer 34 is composed of two
layers of, e.g., Ti layer having thickness of 50 nm and Cu layer
having thickness of 500 nm, and is formed as film over the entire
surface of the principal surface of the first dielectric insulating
layer 27.
[0086] The first wiring layer formation process includes a step of
implementing etching to the portion where the resistor element 9 is
formed with respect. to metallic thin film layer 34, a step of
forming TaN layer 35 over the entire surface thereof, a step of
implementing anodic oxidation processing to the area where resistor
element 9 is formed of the TaN layer 35 to form TaO layer 36, and a
step of removing the TaN layer 35 and the metallic thin film layer
34 which are unnecessary to perform a predetermined patterning to
form first wiring layer 28. At the first wiring layer formation
process, etching processing for performing removal by using, e.g.,
etching liquid consisting of mixed acid of nitric acid, sulphoric
acid, and acetic acid is implemented to metallic thin film layer 34
corresponding to the area where the resistor element 9 is formed.
At the first wiring layer formation process, TaN layer 35 is formed
as film as shown in FIG. 12 by, e.g., sputtering method, etc. in
such a manner to coat the entire surface of the metallic thin film
layer 34 including the area where the resistor element 9 is
formed.
[0087] The TaN layer 35 acts as resistor within the area where the
metallic thin film layer 34 has been removed to thereby constitute
resistor element 9 within the first wiring layer 28. The TaN layer
35 acts as the base of tantalum oxide (TaO) dielectric film formed
by anodic oxidation in forming, as film, capacitor element 8 as
described later. The TaN later 35 is formed as film on the first
dielectric insulating layer 27 or the metallic thin film layer 34
by, e.g., sputtering method so that its thickness is equal to about
20 .mu.m. It is to be noted that Ta thin film may be used as the
TaN layer 35.
[0088] At the first wiring layer formation process, there is
implemented a processing which forms mask layer for anodic
oxidation for allowing lower electrode of the area where the
capacitor element 8 is formed to be faced toward the outside by
opening portion and for coating (covering) other portions. At the
anodic oxidation mask layer, e.g., photoresist in which patterning
can be easily performed is used and it is only required that the
coated portion can maintain sufficient insulating property with
respect to applied voltage at the time of anodic oxidation
processing of the subsequent step. Thus, the oxidation mask layer
is formed so that its thickness is equal to several .mu.m to
several ten .mu.m. It is to be noted that the anodic oxidation mask
layer may be formed by patterning by using other insulating
material by which. thin film can be formed, e.g., silicon oxside
material (SiO.sub.2).
[0089] At the first wiring layer formation process, mask layer for
anodic oxidation is formed as film thereafter to perform anodic
oxidation processing to selectively perform anodic oxidation of the
TaN layer 35 corresponding to the lower electrode of the capacitor
element portion 8 exposed from the opening portion. At the anodic
oxidation processing, e.g., ammonium borate is used as electrolytic
solution, and voltage of 50v to 200v is applied. The applied
voltage is suitably adjusted in order to form film thickness of TaO
dielectric film formed in correspondence with opening portion of
the anodic oxidation mask layer so as to have a desired thickness.
At the first wiring layer formation process, the TaN layer 35
corresponding to the opening portion is selectively oxidized by the
anodic oxidation processing to form TaO layer 36 serving as
dielectric material of capacitor element 8 which will be described
later.
[0090] At the first wiring layer formation process,
photolithographic processing is implemented to the anodic oxidation
mask layer functioning as photoresist layer, and the unnecessary
portion of metallic thin film layer 34 is removed by etching
processing so that predetermined first wiring layer 28 is formed as
shown in FIG. 13. At the first wiring layer formation step, upper
electrode 37 consisting of Ti-Cu film formed by sputtering method,
etc. on the TaO layer 36 in the state where the anodic oxidation
mask layer has been removed is formed as film, and capacitor
element 8 is formed within the first wiring layer 28. It is to be
noted that while the metallic thin film layer 34 is formed by Cu
thin film having small line loss at the high frequency band as
described above, such metallic thin film layer may be. formed by
metallic thin film of, e.g., Al, Pt or Au having tolerance with
respect to the etching liquid.
[0091] While TaN layer 35 is caused to selectively undergo anodic
oxidation in correspondence with the portions where the capacitor
element 8 and the resistor element 9 are formed of the metallic
thin film layer 34 through the anodic oxidation mask at the first
wiring layer formation process, the first wiring layer formation
process is not limited to such process. While photo-resist is used
as. anodic oxidation mask layer at the first wiring layer formation
process, in the case where silicon oxide material is used,
photo-resist is coated on to the anodic oxidation mask in
performing patterning of the first wiring layer 28 so that
photolithographic processing is implemented. In addition, at the
first wiring layer formation step, anodic oxidation of TaN layer
may be also performed over the entire surface thereafter to perform
patterning of formed TaN+TaO layer. At the first wiring layer
formation step, in the case where such processing is implemented,
the surface of the TaN layer formed at the corresponding portion of
the resistor element 9 is also caused to undergo anodic oxidation,
whereby the oxidation film maintains the resistor element 9 as
protective film for a long term.
[0092] A second dielectric insulating layer formation step by
insulating dielectric material similar to the same process as the
formation process for the above-described first dielectric
insulating layer 27 to the principal surface of the first wiring
layer 28 so that second dielectric insulating layer 29 having
uniform thickness is formed as film. At the second dielectric
insulating layer formation step, a large of via holes 33
communicating with electrode portions formed at the first wiring
layer 28 are formed as shown in FIG. 14. A second wiring layer
formation step is implemented to the second dielectric insulating
layer 29.
[0093] The second wiring formation process consists of a step of
forming, as film, metallic thin film layer, a patterning step for
the metallic thin film layer, and a step of implementing
electrolytic plating processing with respect to the metallic thin
film pattern, etc. At the metallic thin film layer formation step,
Ti--Cu layer is formed as film on the principal surface thereof by
the sputtering method, etc. similarly to the formation step for
metallic thin film layer 34 of the above-described first wiring
layer formation process. At the patterning step, photo-resist is
coated onto the entire surface of the metallic thin film layer
thereafter to implement photolithographic processing to thereby
form wiring pattern corresponding to the second wiring layer 30 as
shown in FIG. 15.
[0094] At the electrolytic plating step, e.g., resist layer for
plating having thickness of about 12 .mu.m is formed as pattern
onto the metallic thin film layer thereafter to perform
electrolytic copper plating with the metallic thin film layer being
as electrolyte take-out electrode. At the metallic thin film layer,
copper plating layer of about 10 .mu.m or more is lift-up formed at
opening portion of the plating resist layer. At the electrolytic
plating step, the plating resist layer is removed by rinse, and,
e.g., wet etching processing is implemented to remove unnecessary
metallic thin film layer to thereby form, as film, second wiring
layer 30 consisting of predetermined pattern by the copper plating
layer. At the second wiring layer formation step, inductor element
10 is formed as film at a portion of the second wiring layer 30 by
the above-described electrolytic plating step. As the result of the
fact that the inductor element 10 is formed as thick film by the
electrolytic plating method, the inductor element is formed as film
with a film thickness sufficient to have a predetermined
characteristic.
[0095] Protective layer formation process is implemented to the
second. wiring layer 30 so that protective layer 31 is formed as
film on the principal surface thereof. The protective layer 31 is
formed as the result of the fact that protective layer material,
e.g., solder resist or interlayer insulating layer material, etc.
is uniformly coated by the spin-coat method, etc. At the second
wiring layer formation process, mask coating processing and
photolithographic processing are implemented to the protective
layer 31 so that a large number of opening portions 38 are formed
in correspondence with electrodes 30a formed at the second wiring
layer 30 as shown in FIG. 16. At the second wiring layer formation
process, e.g., electroless Ni--Au plating processing or Ni--Cu
plating processing, etc. is implemented to electrodes 30a exposed
through the opening portions 38 to thereby form, as film, Ni--Au
layer on the electrode 30a as shown in FIG. 17 to perform electrode
formation.
[0096] On the other hand, second wiring pattern 11c formed at the
bottom surface side of the double-sided substrate 1 is coated
(covered) as described above as shown in FIG. 16 so that protective
layer 13 is formed. Similarly to the protective layer 31 of the
above-described high frequency circuit portion 4 side, solder
resist, etc. is uniformly coated by the spin-coat method, etc. on
the protective layer 13 so that the protective layer 13 thus coated
is formed. It is to be noted that the protective layer 13 and the
protective layer 31 may be also formed at the same time by, etc.,
dip method. Similarly to the formation process for opening portion
38, mask coating processing and photolithographic processing are
implemented to the protective layer 13 so that a large number of
opening portions 39 are formed in correspondence with electrodes
formed on the second wiring pattern 11c as shown in FIG. 16. At the
base substrata portion 2, electroless Ni--Au plating processing is
implemented onto the electrodes of the second wiring pattern 11c
through the opening portion 39 so that input/output terminal
electrode 14 is formed.
[0097] At the high frequency circuit portion 4 laminated and formed
on the base substrate portion 2 via the above-mentioned process
steps, as shown in FIG. 4, high frequency ICs5 and chip components
(parts) 6 are mounted from electrodes 30a onto the protective layer
31 by suitable surface mounting method such as film-chip method,
etc. At the mounting step, gold bumps 41 are provided at respective
connecting pads of which details are omitted of the high frequency
ICs 5 and chip components (parts) 6, and the high frequency ICs 5
and the chip component (part) 6 are mounted, by the printing
method, etc., in the state where they are caused to undergo
positioning with respect to high frequency circuit portion 4 to
which solder is delivered. At the mounting step, reflow soldering
is implemented in the state so that high frequency ICs 5 and chip
components 6 are electrically connected onto the high frequency
circuit portion 4 and are mounted thereon. Thus, high frequency
module 1 is manufactured. In this example, at the mounting step,
rinsing step is implemented as occasion demands, and underfill
resin 42 is filled between high frequency IC 5 and the protective
layer 31 as shown in FIG. 4.
[0098] The high frequency module 1 which has been manufactured via
the above-mentioned process steps is mounted, by suitable mounting
method, at interposer (not shown), etc. through input/output
terminal electrode 14 of the base substrate portion 2. The high
frequency module 1 is mounted after undergone positioning on the
interposer to which solder is delivered onto the connection
electrodes in the state where, e.g., gold bumps are provided at the
input/output terminal electrode 14, and is mounted thereon by
implementing reflow soldering.
[0099] As the result of the fact that MEMS switches 7 which can
change capacity characteristic of antenna and/or filter to realize
multi-band function are sealed at the inside of the base substrate
portion 2 within the nitric gas atmosphere in the state where
moisture resistance characteristic and oxidation resistance are
maintained as described above, improvements in the operating
characteristic and durability of the MEMS switch 7 can be realized.
At the high frequency module 1, as the result of the fact that MEMS
switches 7 are provided at the inside of the base substrate portion
2, path lengths with respect to respective wiring layers are
shortened. Thus, low loss and improvement in noise resistance
characteristic can be realized. As the result of the fact that MEMS
switches 7 which are not packaged are used, the high frequency
module 1 can be miniaturized and is permitted to be of the thin
structure.
[0100] At the high frequency module 1, there is formed, with high
accuracy, high frequency circuit portion 4 in which passive
elements 8 to 10 are formed as film on the planarized (flattened)
build-up formation surface 3 of the base substrate portion 2 having
relatively inexpensive double-sided substrate 11. Accordingly, at
the high frequency module 1, improvement in the characteristic and
reduction of cost can be realized, and the base substrate portion 2
is. constituted as wiring portions for the power supply and/or the
ground portion or wiring portions for the control system so that
electrical isolation from the high frequency circuit portion 4 can
be realized. At the high frequency module 1, occurrence of
electrical interference of the high frequency circuit portion 4 is
suppressed so that improvement in the characteristic can be
realized. In addition, since wirings for power supply and/or ground
portion having sufficient area can be formed on the base substrate
portion 2, power supply of high regulation can be performed.
[0101] While, in the above-described high frequency module 1, MEMS
switches 7 are flip-chip mounted with respect to the first wiring
pattern 11b of the double-sided substrate 11, and are accommodated
within MEMS switch accommodating space portion 24 constituted
within the base substrate portion 2, the present invention is not
limited to such configuration. At a high frequency module 45 shown
in FIG. 18, MEMS switch 7 is accommodated within the MEMS switch
accommodating space portion 24 in the state connected to the
double-sided substrate 11 by the wire bonding method. It is to be
noted that since the high frequency module 45 is common to the
above-described high frequency module 1 in other configuration
except for mounting method for MEMS switch 7, common reference
numerals. are respectively attached to common portions, and their
detailed explanation will be omitted.
[0102] At the MEMS switch 7, e.g., adhesive agent is coated onto
the bottom surface of silicon substrate 15. Thus, as shown in FIG.
18, the MEMS switch 7 is connected thereto in the state mounted
after undergone positioning within mounting area of the
double-sided substrate 11. At the MEMS switch 7, wire bonding
method is implemented to the portions between connection pads 16a,
18a for first and third contacts 16 and 18 and connection pads in
which electrode formation has been implemented at the first wiring
patterns 11b so that those connection pads are respectively
connected by wires 46.
[0103] The high frequency module 45 is only required that the MEMS
switch accommodating space portion 24 has length sufficient to hold
the operating area of the movable contact piece 19 of the MEMS
switch 7, thus to realize. thin structure. In this example, at the
double-sided substrate 11, connection pads of the first wiring
pattern 11b are formed in a manner to surround the mounting area of
the MEMS switch 7.
[0104] In a module board 50 shown in FIGS. 19 to 24, glass epoxy
having slightly low moisture absorption characteristic or base
material in which ceramic fillers are dispersed, which is used as
base material of organic wiring board, may be used as material of a
double-sided substrate 51. As described later, the module board 50
is characterized in the configuration in which a shield layer 52 is
formed on at least one principal surface 51a of the double-sided
substrate 51. Since the module board 50 is common to the
above-described base substrate portion 2 in the fundamental
configuration, common reference numerals are respectively attached
to common portions and their detailed explanation will be
omitted.
[0105] At the double-sided substrate 51, as shown in FIG. 20, a
first wiring pattern 11b and a second wiring pattern 11c are
respectively formed on the face principal surface 51a and the back
principal surface 51b. At the double-sided substrate 51, as shown
in FIG. 21, shield layer 52 is formed on the first principal
surface 51a on which MEMS switches 7 are mounted in such a manner
to cover the entire surface thereof. The shield layer 52 consists
of, e.g., silicon oxide (SiO.sub.2) film, silicon nitride
(Si.sub.3N.sub.4) film, silicon carbide (SiC) film, boron nitride
(BN) film, or Diamond Like Carbon (DLC) film having moisture
resistance characteristic and non-transmission characteristic of
active or activated gas molecule such as oxygen, etc., i.e.,
oxidation resistance characteristic.
[0106] The shield layer 52 is formed as film by the above-described
material, whereby the shield layer 52 can be formed as film under
low temperature condition of about 100.degree. C. such that out-gas
is not produced from the double-sided substrate 51 at the time of
film formation. The shield layer 52 is formed as silicon oxide film
or silicon carbide film by, e.g., sputtering method. The shield
layer 52 is formed as silicon nitride film by Chemical Vapor
Deposition (CVD) method under the light assist environment, or is
formed as DLC film by the CVD method.
[0107] Photo-resist is coated onto the entire surface of the shield
layer 52 thereafter to implement photolithographic processing, and
opening portions 53 are formed at portions corresponding to
connection pads of the first wiring pattern 11b as shown in FIG.
22. Nickel-gold plating is implemented to the connection pads
through the opening portions 53 so that electrodes are formed.
[0108] At the double-sided substrate 51, as shown in FIG. 23, MEMS
switch 7 is mounted on the first principal surface 51a. The
mounting of the MEMS switches 7 is performed by, e.g., flip-chip
method similarly to the above-described first embodiment. At the
MEMS switch 7, gold ball bumps 21 are respectively formed on the
first fixed contact 16 and the third fixed contact 18, and these
gold ball bumps 21 are forced to connection pads of the first
wiring pattern 11b through opening portions 53 to apply ultrasonic
wave thereto in the heated state so that the MEMS switches 7 is
mounted on the double-sided substrate 51 as shown in FIG. 23.
[0109] At the double-sided substrate 51, organic insulating block
body 54 shown in FIG. 24 is connected onto the first principal
surface 51a. Also as material of the organic insulating block body
54, there may be used glass epoxy having relatively low moisture
absorption characteristic or base material in which ceramic fillers
are dispersed, which is used as base material of general wiring
board. Thus, the organic insulating block body 54 is also molded as
rectangular block having outer appearance sufficient to cover
(coat) the entire surface of the double-sided substrate 51. and
thickness slightly larger than height of the MEMS switch 7. At the
organic insulating block body 54, a recessed portion 55 having
opening shape sufficient to cover the MEMS switch 7 is formed at
the connecting surface 54a to the double-sided substrate 51. As
described later, in the state where the organic insulating block
body 54 is connected onto the double-sided substrate 51, the
recessed portion 55 constitutes MEMS switch accommodating space
portion which seals MEMS. switch therewithin under the condition
where moisture resistance characteristic and oxidation resistance
characteristic are maintained.
[0110] At the organic insulating block body 54, shield layer 56 is
formed as film on the entire surface of connecting surface 54a
including recessed portion 55 similarly to the shield layer 52 of
the above-described double-sided substrate 51 side. It is to be
noted that since the shield layer 56 is formed also at the internal
surface of the recessed portion 55, such shield layer 56 may be
constituted by, e.g., metallic plating layer formed as film by the
MID method. At the organic insulating block body 54, adhesive agent
layer 57 is coated and formed at the connecting surface 54a except
for the recessed portion 55. As the adhesive agent layer, there is
used ultrasonic hardening type adhesive agent or thermo-hardening
type adhesive agent which is generally used in the manufacturing
process for multi-layer substrate. It is to be noted that in the
case where the ultrasonic hardening type adhesive agent is used,
the organic insulating block body 54 has ultraviolet ray
transmission characteristic.
[0111] The double-sided substrate 51 and the organic insulating
block body 54 which have been described above are connected in
combination after they are caused to undergo positioning to each
other in such a manner to accommodate MEMS switches 7 at the inside
of the recessed portion 55 within nitric box to thereby manufacture
module board 50 shown in FIG. 19. At the module board 50, the
recessed portion 55 constitutes MEMS switch accommodating space
portion in which moisture resistance characteristic and oxidation
resistance characteristic are maintained by the shield layer 52 and
the shield-layer 56 to seal the MEMS switches 7. At the module
board 50, since the double-sided substrate 51 and/or the organic
insulating block body 54 are formed by relatively inexpensive
material, reduction of cost can be realized.
[0112] At the module board 50, a suitable wiring pattern 58 is
formed on the principal surface of the organic insulating block
body 54. The wiring pattern 58 is interlayer-connected to the first
wiring pattern 51a through via 59. Planarization (flattening)
processing is implemented to the principal surface where the wiring
pattern 58 is formed of the wiring pattern 58, and the
above-described high frequency circuit portion 4 is laminated and
formed to constitute high frequency module. It is to be noted that,
at the module board 50, e.g., ultrasonic welding method, etc. may
be implemented to the double-sided substrate 51 and the organic
insulating block body 54 to thereby integrate them. At the module
board 50, either one of the double-sided substrate 51 and the
organic insulating block body 54 may be molded by material
excellent in the heat resistance characteristic, the chemicals
resistance characteristic or moisture resistance characteristic
similarly to materials of the double-sided substrate 11 or the
organic insulating block body 12 of the above-described base
substrate portion 2 to thereby allow the shield layer to be
unnecessary. Even in the case where the module board 50 is molded
by such material, shield layer is formed so that further
improvement in the reliability can be realized.
[0113] At the base substrate portion 2 and the module board 50
which have been described above, the step of mounting MEMS switch 7
and the step of connecting the double-sided substrates 11, 51 and
the organic insulating block bodies 12, 54 are performed within the
nitric gas atmosphere to thereby hermetically introduce or fill
nitric gas into the inside of the MEMS switch accommodating space
portions 24, 55.
[0114] Then, at a high frequency module 60 shown in FIGS. 25 and
27, a ventilation hole 63 is formed at the double-sided substrate
62 in which the organic insulating block body 12 is connected to
constitute a base substrate portion 61. At the high frequency
module 60, the step of mounting MEMS switch 7 and the step of
connecting the double-sided substrate 62 and the organic insulating
block body 12 are performed under the atmospheric environment.
Since other configurations of the high frequency module 60 are
equivalent to those of the above-described high frequency module 1,
the same reference numerals are respectively attached to
corresponding portions, and their explanation will be omitted.
[0115] At the double-sided substrate 62, as shown in FIG. 26, MEMS
switch 7 is mounted by the flip-chip method on the principal
surface thereof. The step of mounting MEMS switch 7 is performed
under the atmospheric environment. At the double-sided substrate
62, as shown in FIG. 26, ventilation hole 63 which penetrates the
face principal surface and the back principal surface thereof is
formed at the area where MEMS switch 7 is mounted. At the
double-sided substrate 62, organic insulating block body 12 is
connected onto the principal surface thereof via the step of
mounting MEMS switch 7 to constitute base substrate portion 61. The
step of connecting the organic insulating block body 12 is also
performed under the atmospheric environment.
[0116] At the base substrate portion 61, the ventilation hole 63
communicates with the MEMS switch accommodating space portion 24 in
this state, and the MEMS switch accommodating space portion 24 is
placed in the atmospheric environment. At the base substrate
portion 61, although not shown, the ventilation unit is connected
to the ventilation hole, and air vent (deflating) operation within
the MEMS switch accommodating space portion 24 is performed through
the ventilation hole 63. At the base substrate portion 61, the
inside of the MEMS switch accommodating space portion 24 is placed
in substantially vacuum state by the ventilation unit. Thereafter,
filling operation of nitric gas is performed.
[0117] At the base substrate portion 61, nitric gas is filled into
the MEMS switch accommodating space portion 24 thereafter to fill
filler 64 such as metal, glass excellent in air-tightness or resin,
etc. into ventilation hole 63 from the bottom surface side of the
double-sided substrate 62 to thereby close the ventilation hole 63
as shown in FIG. 27. At the base substrate portion 61, nitric gas
is hermetically introduced or filled. into the MEMS switch
accommodating space portion 24 to thereby accommodate the MEMS
switches 7 in the state where moisture resistance characteristic
and oxidation resistance characteristic are maintained. In this
example, polishing processing is implemented also to filler 64
along with insulating resin layer 26 formed by coating solder
resist, etc. also with respect to the bottom surface side of the
double-sided substrate 62 so that the entirety of the base
substrate portion 61 is planarized (flattened).
[0118] At the base substrate portion 61 manufactured as described
above, wiring pattern 12a is formed on the principal surface of the
organic insulating block body 12, and insulating resin layer is
formed as film and polishing processing is implemented thereto so
that planarized (flattened) buildup formation surface 3 is formed.
At the base substrate portion 61, high frequency circuit portion 4
is laminated and formed on the build-up formation surface 3. In
addition, high frequency ICs 5 and chip components (parts) 6 are
mounted on the high frequency circuit portion 4 to manufacture high
frequency module 60.
[0119] It is to be noted that while ventilation hole 63 is formed
at the double-sided substrate 62 in the high frequency module 60,
ventilation hole may be formed at the organic insulating block body
12 side. Since the organic insulating block body 12 constitutes
build-up formation surface of which principal surface has been
planarized (flattened) and high frequency circuit portion 4 is
laminated and formed thereon, polishing processing is implemented
also to filler for closing ventilation holes, the organic
insulating block 12 is planarized (flattened).
[0120] It is to be noted that while, in the above-described
respective examples, MEMS switch accommodating space portion 24 is
formed within the base substrate portion 2 to seal the MEMS switch
in the state where moisture resistance characteristic and oxidation
resistance characteristic are maintained, the present invention is
not limited to such configuration (implementation). The high
frequency module may be adapted so that, element body, e.g.,
Surface Acoustic Wave element (SAW) having movable portion, etc.
may be sealed along with MEMS switches 7 as element body within the
MEMS switch accommodating space portion 24. It is a matter of
course that the high frequency module may be adapted so that
Surface Acoustic Wave element may be sealed at accommodating space
portion formed similarly to the MEMS switch accommodating space
portion 24 within the base substrate portion 2.
[0121] At the high frequency module according to the present
invention, not only element body having movable portion, but also
IC chips or LSI chips for micro wave or mili wave in which, e.g.,
resin coat is implemented so that the characteristic is
considerably deteriorated may be sealed as element body at
accommodating space portion formed within the base substrate
portion 2. Such accommodating space portion is also formed in the
state where moisture resistance characteristic is maintained
similarly to the MEMS switch accommodating space portion 24 so that
the element body is permitted to exhibit sufficient characteristic
and protection can be made with respect to mechanical load from the
external, etc. so that there is also no possibility that damage,
etc. at the time of reflow soldering may take place.
[0122] It is to be noted that while the invention has been
described in accordance with preferred embodiments thereof
illustrated in the accompanying drawings and described in detail,
it should be understood by those ordinarily skilled in the art that
the invention is not limited to embodiments, but various
modifications, alternative constructions or equivalents can be
implemented without departing from the scope and spirit of the
present invention as set forth by appended claims.
INDUSTRIAL APPLICABILITY
[0123] As described above, in accordance with the present
invention, since element body is constituted at the inside of the
wiring layer, and element body is directly formed within element
body accommodating space where the moisture resistance
characteristic and oxidation resistance characteristic are
maintained, package for maintaining moisture resistance
characteristic and/or oxidation resistance characteristic, and/or
for protecting the element body or bodies from mechanical load from
the external is not required at the element body. As a result,
miniaturization thereof can be realized and path length with
respect to the wiring layer is shortened. Thus, board device for
module in which low loss and improvement in noise resistance
characteristic have been realized can be obtained. Moreover, in
accordance with the present invention, aging deterioration of the
element body is maintained in a manner equivalent to the packaged
state so that stable operation is performed, and occurrence of
inconvenience such as damage, etc. by evaporation of moisture
immersed into the inside of the element body accommodating space
portion. is prevented in. implementing reflow soldering, etc. Thus,
high accuracy module board device can be efficiently obtained.
[0124] Further, in accordance with the present invention, since the
MEMS switch which can change capacity characteristic of antenna
and/or filter to realize multi-band function, and/or element body
of which characteristic is deteriorated by resin coating, etc. are
constituted within the wiring layer of the base substrate portion,
and are directly formed at the element body accommodating space
portion in which moisture resistance characteristic and/or
oxidation resistance characteristic are maintained, package for
maintaining moisture resistance characteristic and/or oxidation
resistance characteristic, and/or protecting the element body or
bodies from mechanical load from the external is not required at
the element body. As a result, miniaturization thereof can be
realized and path length with respect to wiring length is
shortened. Thus, high frequency module in which low loss and
improvement in noise resistance characteristic have been improved
can be obtained. Furthermore, in accordance with. the present
invention, aging deterioration of element body is maintained in a
manner equivalent to the packaged state so that stable operation is
performed, and occurrence of inconvenience such as damage, etc. of
package by evaporation of moisture immersed into the inside is also
prevented in reflow soldering, etc. Thus, high accuracy high
frequency module can be efficiently obtained. Still furthermore, in
accordance with the present invention, high frequency circuit
portion in which various passive elements are formed on the
planarized (flattened) build-up formation surface of the base
substrate portion including relatively inexpensive organic
substrate is formed with high accuracy. As a result, reduction of
the cost can be realized, and the base substrate portion is
constituted as, e.g., wiring portions for power supply and/or
ground portion, and/or, wiring portion for the control system so
that high frequency module in which electric isolation from the
high frequency portion has been realized can be obtained. In
accordance with the present invention, occurrence of electric
interference of the high frequency circuit portion is suppressed so
that improvement in the characteristic can be realized, and wirings
for power supply and/or ground portion having sufficient area can
be formed at the base substrate portion. From this fact, high
frequency module in which power supply of high regulation is
performed can be obtained.
* * * * *