U.S. patent application number 12/153431 was filed with the patent office on 2008-09-25 for power module member manufactured by wet treatment, and wet treatment method and wet treatment equipment thereof.
This patent application is currently assigned to DOWA MINING CO.,LTD. Invention is credited to Ken Iyoda, Makoto Namioka, Hideyo Osanai, Susumu Shimada.
Application Number | 20080230515 12/153431 |
Document ID | / |
Family ID | 27807048 |
Filed Date | 2008-09-25 |
United States Patent
Application |
20080230515 |
Kind Code |
A1 |
Iyoda; Ken ; et al. |
September 25, 2008 |
Power module member manufactured by wet treatment, and wet
treatment method and wet treatment equipment thereof
Abstract
The present invention provides a method of forming a circuit
pattern on an integrally bonded member, the method not requiring a
correction step of a laminate film or a resist film which has been
necessary at the time of wet treatment of the integrally bonded
member. After a circuit pattern forming metal plate is bonded on a
part of a ceramic substrate so as to expose an outer peripheral
edge portion of the ceramic substrate in an integrally bonded
member, the integrally bonded member is set on a treating apparatus
while being covered with a masking member having a window portion
from which the circuit pattern forming metal plate of the
integrally bonded member is exposed. Further, the integrally bonded
member is pressed with an appropriate pressure from a base plate
side so that a boundary surface between a portion surrounding the
window portion in the masking member and an exposed surface of the
ceramic substrate which is exposed in a metal-ceramic bonded member
has a state not allowing a liquid to pass therethrough. Thereafter,
a treatment solution for wet treatment is injected from an
injection pipe to be in contact with the circuit pattern forming
metal plate.
Inventors: |
Iyoda; Ken; (Tokyo, JP)
; Namioka; Makoto; (Tokyo, JP) ; Osanai;
Hideyo; (Tokyo, JP) ; Shimada; Susumu; (Tokyo,
JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 320850
ALEXANDRIA
VA
22320-4850
US
|
Assignee: |
DOWA MINING CO.,LTD
Tokyo
JP
|
Family ID: |
27807048 |
Appl. No.: |
12/153431 |
Filed: |
May 19, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10397429 |
Mar 27, 2003 |
7387741 |
|
|
12153431 |
|
|
|
|
Current U.S.
Class: |
216/41 ;
156/345.19; 257/E23.106 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H01L 2924/00 20130101; H01L 2924/0002 20130101; H05K 3/068
20130101; H05K 3/0085 20130101; H01L 23/3735 20130101; H01L 21/4846
20130101 |
Class at
Publication: |
216/41 ;
156/345.19 |
International
Class: |
C23F 1/02 20060101
C23F001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 29, 2002 |
JP |
2002-96302 |
Nov 19, 2002 |
JP |
2002-335638 |
Claims
1. A wet treatment method of a metal-ceramic bonded member of a
base integral type which is so structured that a metal-ceramic
bonded member is bonded on a base member, the metal-ceramic bonded
member being constituted of a ceramic substrate and a circuit
pattern forming metal plate bonded on the ceramic substrate, the
method comprising: having a masking member cover said metal-ceramic
bonded member of the base integral type in which said base member
is bonded on said ceramic substrate so as to be exposed in a
portion surrounding said ceramic substrate, said masking member
having a window portion from which said ceramic substrate is
exposed; pressing said masking member against said exposed base
member so as to prevent a treatment solution for said wet treatment
from passing through a portion where said masking member and the
base member exposed in the portion surrounding said ceramic
substrate are in contact with each other; and during pressing said
masking member, bringing the treatment solution for the wet
treatment of said circuit pattern forming metal plate into contact
with said circuit pattern forming metal plate.
2. A wet treatment method of a metal-ceramic bonded member of a
base integral type according to claim 1, wherein said base member
has a plate shape or a fin structure.
3. A wet treatment method of a metal-ceramic bonded member and a
metal-ceramic bonded member of a base integral type according to
claim 2, wherein said treatment solution is an etching solution for
said circuit pattern forming metal plate, and wherein the circuit
pattern forming metal plate of said metal-ceramic bonded member is
covered with the masking member having the window portion from
which said circuit pattern forming metal plate is exposed, after a
projection patter having a resistance to said etching solution is
formed on a desired portion.
4. A wet treatment method of a metal-ceramic bonded member and a
metal-ceramic bonded member of a base integral type according to
claim 2, wherein said treatment solution is a plating solution for
said circuit pattern forming metal plate.
5. A wet treatment method of a metal-ceramic bonded member and a
metal-ceramic bonded member of a base integral type according to
claim 2, wherein said treatment solution is a plating solution for
said circuit pattern forming metal plate, and wherein the circuit
pattern forming metal plate of said metal-ceramic bonded member is
covered with the masking member having the window portion from
which said circuit pattern forming metal plate is exposed, after a
protection pattern preventing plating with said plating solution is
formed on a desired portion.
6. A wet treatment method of a metal-ceramic bonded member and a
metal-ceramic bonded member of a base integral type according to
claim 3, wherein an appropriate resist is applied to or an
appropriate film is laminated on said circuit pattern forming metal
plate to form said protection pattern.
7. A masking member which is used for a wet treatment method of a
metal-ceramic bonded member of a base integral type which is so
structured that a metal-ceramic bonded member is bonded on a base
member, the metal-ceramic bonded member being constituted of a
ceramic substrate and a circuit pattern forming metal plate bonded
on the ceramic substrate, and which has a window portion from which
said circuit pattern forming metal plate is exposed, wherein a
portion surrounding said window portion is pressed against said
ceramic substrate or said base member.
8. A masking member according to claim 7, further comprising: a
base having said window portion; a pressing portion having said
window portion and deformable by a pressing force; and a plurality
of elastic members, wherein said pressing portion is disposed on
said base via said plural elastic members, wherein said
metal-ceramic bonded member of the base integral type is disposed
on said pressing portion, and wherein said metal-ceramic bonded
member of the base integral type is pressed against said pressing
portion.
9. A wet treatment equipment having a tank which feeds a treatment
solution to a metal plate bonded on a substrate to perform wet
treatment of the metal plate, the wet treatment equipment
comprising: a treatment solution feeding portion, which is provided
in said tank, to feed the treatment solution to said metal plate; a
substrate setting portion, which is provided on an upper surface or
a side surface of said tank, to set said substrate thereon; and an
opening portion of said tank to expose to an inner part of said
tank the metal plate bonded on the substrate which is set on said
substrate setting portion.
10. A wet treatment equipment according to claim 9, wherein the
opening portion of said tank is provided with a guide member to
movably set said substrate on said opening portion.
11. A wet treatment equipment according to claim 9, wherein said
substrate with said masking member attached thereto is subjected to
the wet treatment.
12. A power module member, being manufactured from the
metal-ceramic bonded member or the metal-ceramic bonded member of
the base integral type by the wet treatment method according to
claim 2.
13. A power module, being manufactured from the power module member
according to claim 12.
Description
[0001] This is a Continuation of application Ser. No. 10/397,429
filed Mar. 27, 2003. The disclosure of the prior application is
hereby incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a method of forming a
circuit pattern on a metal-ceramic bonded member constituted of a
circuit pattern forming metal plate and a ceramic substrate which
are bonded on each other, and further on a metal-ceramic bonded
member of a base integral type in which a surface of the ceramic
substrate opposite a surface having the circuit pattern forming
metal bonded thereon is bonded on a base member (hereinafter,
described as an integrally bonded member), a masking member, a wet
treatment equipment for forming the circuit pattern, and so on.
DESCRIPTION OF THE RELATED ART
[0003] As a method of forming circuit patterns on conductive metal
films provided on various kinds of substrates, a wet treatment
method such as an etching process or plating is in wide use.
[0004] In this wet treatment method for the metal film, laminate
coating is applied to portions not requiring the treatment, or a
resist film or the like is provided on these portions by screen
printing in advance so as to prevent a treatment solution such as
an etching solution or a plating solution from coming into contact
with the metal film (for example, refer to a patent document
1).
[0005] Japanese Patent Laid-open No. Sho 63-65653 (page 3)
[0006] In order to respond to a demand for passing a large amount
of current through a circuit pattern provided on a substrate, a
metal-ceramic bonded member in which a circuit pattern forming
metal plate is bonded on a ceramic substrate, a base integrally
bonded member in which a surface of the ceramic substrate opposite
a surface having the circuit pattern forming metal plate bonded
thereon is bonded on a base member, and the like have been
developed. However, it has been found out that the following
problems exist when the circuit pattern is formed on the circuit
pattern forming metal plate of the integrally bonded member by a
conventional method and a conventional circuit pattern treating
apparatus is used.
[0007] The base member, which is bonded on the integrally bonded
member as described above, is required to have thermal conduction
and mechanical strength, and therefore, metal such as aluminum and
copper, and a composite material of these metals and ceramic are
suitably used. In order to prevent this base member from undergoing
undesired wet treatment due to its contact with the treatment
solution used for the wet treatment method, the wet treatment is
performed in such a manner that laminate coating or resist coating
is applied all over the integrally bonded member in advance, and an
immersion method in the treatment solution, a showering method of
the treatment solution, or the like is carried out after a laminate
film or a resist film only on portions to be subjected to the wet
treatment is removed.
[0008] However, in the integrally bonded member, both of the
circuit pattern forming metal plate and the ceramic substrate
constituting the integrally bonded member have a considerable
thickness (for example, about 300 .mu.m to about 500 .mu.m for the
circuit pattern forming metal plate and about 200 .mu.m to about
800 .mu.m for the ceramic substrate). Because of this, when the
laminate coating or the resist coating is applied all over the
integrally bonded member, the laminate film or the resist film
cannot follow a level difference in rising portions or the like
from the base member to the ceramic substrate, though having no
problem on flat portions, so that gaps are sometimes caused between
the integrally bonded member and the laminate film or the resist
film.
[0009] When the laminate film or the resist film applied on the
integrally bonded member is removed according to a desired circuit
pattern in the state of having the gaps and the wet treatment is
further applied, the treatment solution passes from portions where
the laminate film or the resist film is removed to the gaps to
enter the base member so that the base member may possibly be
subjected to undesired treatment. Moreover, it is difficult to
provide the resist film on side surfaces of the base member by an
ordinary forming method which uses laminate coating or screen
printing.
[0010] Especially when the aforesaid treatment is an etching
process, the etching solution used therein is required to
efficiently etch the circuit pattern forming metal plate which is
far thicker than an ordinary metal film for a print circuit
substrate. Hence, the etching solution is prescribed using a
chemical having an extremely high etching capability, but it is
concerned that this may frequently cause undesirable etching
process to be applied to the base member.
[0011] Here, in order to avoid such a problem, a so-called
correction step can be considered, the correction step being such
that an operator applies a resist again using a brush or the like
to portions which may possibly have gaps, after the laminate
coating or the resist coating is applied all over the integrally
bonded member. However, the execution of the correction step
hinders productivity improvement of the wet treatment step of the
integrally bonded member, and turns out to be a main cause of
production cost increase of the integrally bonded member.
[0012] FIG. 7 is a perspective view when a circuit pattern is to be
formed by an etching process on an integrally bonded member 110
according to the conventional art to which the aforesaid laminate
coating or the resist coating is applied (hereinafter, described as
an integrally bonded member according to the conventional art),
using a treating apparatus 130 according to the conventional art.
In the treating apparatus 130 according to the conventional art, an
etching solution injection pipe 135, a conveyer 150 composed of
shafts 151 and wheels 152 are provided in a treatment tank 131.
[0013] The integrally bonded member 110 according to the
conventional art is transferred on the conveyer 150 by the rotation
of the wheels 152, with a circuit pattern forming metal plate
thereof facing downward, and at this time, it receives an injection
of an etching solution 133 from the injection pipe 135 provided
under the conveyor 150 so that the circuit pattern forming metal
plate is etched. The etching solution 133 injected to the inside of
the treatment tank 131 is pooled in a bottom portion thereof to be
pressure-sent to the injection pipe 135 by a pump 134.
[0014] However, when the circuit pattern forming metal plate of the
integrally bonded member 110 according to the conventional art is
etched through the use of the conventional treating apparatus 130,
most of the etching solution 133 injected from the injection pipe
135 reaches the integrally bonded member 110 according to the
conventional art after hitting the shafts 151 or the wheels 152.
This lowers etching efficiency since a kinetic energy of the
etching solution 133 is not usable for etching the circuit pattern
forming metal plate. Further, due to need for a large number of the
shafts 151 for holding the integrally bonded member according to
the conventional art, the structure of the wet treatment equipment
is made complicated, which forces the scale of the facility to be
large in order to prevent leakage of the etching solution.
SUMMARY OF THE INVENTION
[0015] Such being the situation, it is an object of the present
invention to provide a wet treatment method of an integrally bonded
member not requiring a correction step, a wet treatment equipment
with a high etching efficiency, and a masking member used for wet
treatment, and further a power module member and the like which are
manufactured from a metal-ceramic bonded member and the integrally
bonded member using the wet treatment method and so on.
[0016] A first means for achieving the above-described object is a
wet treatment method of a metal-ceramic bonded member constituted
of a ceramic substrate and a circuit pattern forming metal plate
bonded on the ceramic substrate, the method comprising:
[0017] having a masking member cover the metal-ceramic bonded
member in which the circuit-pattern forming metal plate is bonded
so as to expose an outer peripheral edge portion of the ceramic
substrate, the masking member having a window portion from which
the circuit pattern forming metal plate is exposed;
[0018] pressing the masking member against an exposed surface of
the ceramic substrate so as to prevent a treatment solution for the
wet treatment from passing through a portion where the masking
member and the exposed outer peripheral edge portion of the ceramic
substrate are in contact with each other; and
[0019] during pressing the masking member, bringing the treatment
solution for the wet treatment of the circuit pattern forming metal
plate into contact with the circuit pattern forming metal
plate.
[0020] The first means disables the treatment solution from passing
through the portion where the masking member and the exposed outer
peripheral edge portion of the ceramic substrate are in contact
with each other at the time when the wet treatment using the
treatment solution is applied to the metal-ceramic bonded member
covered with the masking member, and consequently, the contact of
the treatment solution with the base member can be avoided to
eliminate the necessity of resist coating or film laminating all
over the metal-ceramic bonded member, thereby eliminating the
necessity of a correction step.
[0021] A second means is a wet treatment method of a metal-ceramic
bonded member of a base integral type which is so structured that a
metal-ceramic bonded member is bonded on a base member, the
metal-ceramic bonded member being constituted of a ceramic
substrate and a circuit pattern forming metal plate bonded on the
ceramic substrate, the method comprising:
[0022] having a masking member cover the metal-ceramic bonded
member of the base integral type in which the base member is bonded
on the ceramic substrate so as to be exposed in a portion
surrounding the ceramic substrate, the masking member having a
window portion from which the ceramic substrate is exposed;
[0023] pressing the masking member against the exposed base member
so as to prevent a treatment solution for the wet treatment from
passing through a portion where the masking member and the base
member exposed in the portion surrounding the ceramic substrate are
in contact with each other; and
[0024] during pressing the masking member, bringing the treatment
solution for the wet treatment of the circuit pattern forming metal
plate into contact with the circuit pattern forming metal
plate.
[0025] In the above-described structure, the treatment solution
does not come in contact with the circuit pattern forming metal
plate even when the treatment solution stays in a portion where the
masking member and an exposed peripheral edge portion of the
ceramic substrate are in contact with each other, at the time when
the wet treatment using the treatment solution is applied to the
metal-ceramic bonded member of the base integral type covered with
the masking member. Consequently, the wet treatment of the circuit
pattern forming metal plate can be stably and uniformly performed.
Further, since the treatment solution is unable to pass through the
portion where the masking member and the base member are in contact
with each other, the contact of the treatment solution with the
base member can be practically avoided so that resist coating or
film laminating over the whole metal-ceramic bonded member of the
base integral type is not required to eliminate the necessity of a
correction step.
[0026] A third means is a wet treatment method of a metal-ceramic
bonded member of a base integral type according to the second
means, in which the base member has a plate shape or a fin
structure.
[0027] The wet treatment method of the metal-ceramic bonded member
of the base integral type according to the second means is also
suitably applicable when the base member is a base plate having a
plate shape or has the fin structure.
[0028] A fourth means is a wet treatment method of a metal-ceramic
bonded member and a metal-ceramic bonded member of a base integral
type according to any one of the first to third means, in which
[0029] the treatment solution is an etching solution for the
circuit pattern forming metal plate, and
[0030] the circuit pattern forming metal plate of the metal-ceramic
bonded member is covered with the masking member having the window
portion from which the circuit pattern forming metal plate is
exposed, after a protection pattern having a resistance to the
etching solution is formed on a desired portion.
[0031] The etching solution for the circuit pattern forming metal
plate is used as the treatment solution, and the protection pattern
having a resistance to the etching solution is formed in advance on
the desired portion of the circuit pattern forming metal plate so
that the circuit pattern forming metal plate can be etched into a
desired circuit pattern.
[0032] A fifth means is a wet treatment method of a metal-ceramic
bonded member and a metal-ceramic bonded member of a base integral
type according to any one of the first to third means, in which
[0033] the treatment solution is a plating solution for the circuit
pattern forming metal plate.
[0034] The plating solution for the circuit pattern forming metal
plate is used as the treatment solution so that desired plating can
be applied to the circuit pattern forming metal plate.
[0035] A sixth means is a wet treatment method of a metal-ceramic
bonded member and a metal-ceramic bonded member of a base integral
type according to any one of the first to third means, in which
[0036] the treatment solution is a plating solution for the circuit
pattern forming metal plate, and
[0037] the circuit pattern forming metal plate of the metal-ceramic
bonded member is covered with the masking member having the window
portion from which the circuit pattern forming metal plate is
exposed, after a protection pattern preventing plating with the
plating solution is formed on a desired portion.
[0038] The plating solution for the circuit pattern forming metal
plate is used as the treatment solution, and the protection pattern
preventing the plating with the plating solution is formed in
advance on the desired place of the circuit pattern forming metal
plate so that desired plating can be applied to a desired portion
in the circuit pattern forming metal plate.
[0039] A seventh means is a wet treatment method of a metal-ceramic
bonded member and a metal-ceramic bonded member of a base integral
type according to any one of the fourth to sixth means, in
which
[0040] an appropriate resist is applied to or an appropriate film
is bonded on the circuit pattern forming metal plate to form the
protection pattern.
[0041] In the above-described structure, since the treatment
solution is unable to pass through the portion where the masking
member and the exposed outer peripheral edge portion of the ceramic
substrate are in contact with each other, the appropriate resist or
the like only needs to be applied to or laminated on a portion
where the formation of the protection pattern is desired.
Consequently, a highly productive and low-cost printing method is
applicable as, for example, a resist coating method.
[0042] An eighth means is a masking member which is used for a wet
treatment method of a metal-ceramic bonded member of a base
integral type so structured that a metal-ceramic bonded member is
bonded on a base member, the metal-ceramic bonded member being
constituted of a ceramic substrate and a circuit pattern forming
metal plate bonded on the ceramic substrate, and which has a window
portion from which the circuit pattern forming metal plate is
exposed,
[0043] a portion surrounding the window portion being pressed
against the ceramic substrate or the base member.
[0044] Wet treatment using a treatment solution is applied to the
circuit pattern forming metal plate while the metal-ceramic bonded
member of the base integral type is covered with the masking member
as structured above, so that resist coating or film laminating all
over the metal-ceramic bonded member of the base integral type
becomes unnecessary to eliminate the necessity of a correction
step.
[0045] A ninth means is a masking member according to the eighth
means, comprising:
[0046] a base having the window portion; a pressing portion having
the window portion and deformable by a pressing force; and a
plurality of elastic members,
[0047] in which
[0048] the pressing portion is disposed on the base via the plural
elastic members,
[0049] the metal-ceramic bonded member of the base integral type is
disposed on the pressing portion, and
[0050] the metal-ceramic bonded member of the base integral type is
pressed against the pressing portion.
[0051] Even when the base member of the metal-ceramic bonded member
of the base integral type which is to be masked has undulation, the
pressing portion of the masking member structured above is pressed
against the base member to deform along the undulation, so that the
masking member can prevent the infiltration of the treatment
solution into a masked portion of the metal-ceramic bonded member
of the base integral type.
[0052] A tenth means is a wet treatment equipment having a tank
which feeds a treatment solution to a metal plate bonded on a
substrate to perform wet treatment of the metal plate, the wet
treatment equipment comprising:
[0053] a treatment solution feeding portion, which is provided in
the tank, to feed the treatment solution to the metal plate;
[0054] a substrate setting portion, which is provided on an upper
surface or a side surface of the tank, to set the substrate
thereon; and
[0055] an opening portion of the tank to expose to an inner part of
the tank the metal plate bonded on the substrate which is set on
the substrate setting portion.
[0056] Since the wet treatment equipment as structured above is
able to directly feed the treatment solution to the substrate which
is set on the upper surface or the side surface of the tank, an
effective use of the treatment solution fed from the treatment
solution feeding portion is possible, and since the metal-ceramic
bonded member of the base integral type can be stably supported on
the treatment tank, stable and uniform wet treatment of the circuit
pattern forming metal plate is possible.
[0057] An eleventh means is a wet treatment equipment according to
the tenth means, in which
[0058] the opening portion of the tank is provided with a guide
member to movably set the substrate on the opening portion.
[0059] The wet treatment equipment as structured above can perform
the wet treatment of the substrate successively to achieve a high
productivity of the wet treatment step.
[0060] A twelfth means is a wet treatment equipment according to
the tenth or the eleventh means, in which the substrate with the
masking member attached thereto is subjected to the wet
treatment.
[0061] The wet treatment equipment as structured above can apply
the wet treatment to the substrate only by attaching the masking
member thereto so that productivity of the wet treatment step can
be enhanced.
[0062] A thirteenth means is a power module member, being
manufactured from the metal-ceramic bonded member or the
metal-ceramic bonded member of the base integral type by the wet
treatment method according to any one of the first to seventh
means.
[0063] A fourteenth means is a power module, being manufactured
from the power module member according to the thirteenth means.
BRIEF DESCRIPTION OF THE DRAWINGS
[0064] FIG. 1 is a schematic cross sectional view of wet treatment
of an integrally bonded member according to an embodiment;
[0065] FIG. 2 is a perspective view of the integrally bonded member
according to the embodiment;
[0066] FIG. 3 is a perspective view of a masking member according
to the embodiment;
[0067] FIG. 4 is a perspective view when the integrally bonded
member is covered with the masking member according to the
embodiment;
[0068] FIG. 5 is a cross sectional view when the integrally bonded
member is covered with a masking member according to another
embodiment;
[0069] FIG. 6A is a schematic perspective view of wet treatment of
the integrally bonded member according to the other embodiment;
[0070] FIG. 6B is a schematic cross sectional view of FIG. 6A;
[0071] FIG. 7 is a schematic perspective view of wet treatment of
an integrally bonded member according to a conventional art;
[0072] FIG. 8 is a cross sectional view when the integrally bonded
member is covered with a masking member according to still another
embodiment;
[0073] FIG. 9 is a cross sectional view when an integrally bonded
member according to yet another embodiment is covered with the
masking member; and
[0074] FIG. 10 is a cross sectional view taken along the arrow A in
FIG. 8 and FIG. 9.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
Embodiment 1
[0075] Hereinafter, (Embodiment 1) according to the present
invention will be explained with reference to FIG. 1 to FIG. 4.
[0076] FIG. 1 is a schematic cross sectional view when desired wet
treatment is applied to an integrally bonded member covered with a
masking member according to this embodiment, FIG. 2 is a
perspective view of the integrally bonded member according to this
embodiment, FIG. 3 is a perspective view of the masking member
having a substantially equal shape to a square measuring box
according to this embodiment, seen from a recessed portion side of
the substantially equal shape to the square measuring box, and FIG.
4 is a perspective view of the masking member having the
substantially equal shape to the square measuring box according to
this embodiment, seen from a window portion side of the masking
member when the masking member covers the integrally bonded
member.
[0077] First, in FIG. 2, an integrally bonded member 10 is so
structured that a desired number (an example of three is shown in
FIG. 2) of metal-ceramic bonded members 14 each constituted of a
ceramic substrate 12 and a circuit pattern forming metal plate 13
bonded on each other are provided on a base plate 11 which is a
base member including metal or a composite material of metal,
ceramic, and so on, and a ceramic substrate side opposite the
circuit pattern forming metal plate 13 of each of the metal-ceramic
bonded members 14 is bonded on the base plate 11.
[0078] In the metal-ceramic bonded member 14, the circuit pattern
forming metal plate 13 is bonded on a part of the ceramic substrate
12 so as to expose an outer peripheral edge portion of the ceramic
substrate 12, the exposed outer peripheral edge portion having a
width d (d=about 0.5 mm to about 1.5 mm).
[0079] An exposed surface 16 of the outer peripheral edge portion
in this ceramic substrate 12 comes in contact with a masking
member, which will be described later, thereby preventing the
passage of a treatment solution for wet treatment which tries to
pass through this portion and ensuring withstand voltage of an
electronic circuit to be formed on the circuit pattern forming
metal plate 13 and the base plate 11.
[0080] On the circuit pattern forming metal plate 13, a protection
pattern 15 patterned after, for example, a desired circuit pattern
is provided.
[0081] Metal having a high thermal conduction and high mechanical
strength such as aluminum and copper, and a composite material of
these metals and ceramic are suitably used as the base plate 11.
Aluminum nitride or the like having a high electrical resistance
and a high thermal conduction is suitably used as the ceramic
substrate 12. Metal having a high electrical conduction such as
aluminum and copper, and an alloy of these metals are suitably used
as the circuit pattern forming metal plate 13.
[0082] Next, in FIG. 3, the masking member 20 has a recessed
portion 21 provided in a center portion thereof, and window
portions 22 provided in a bottom surface of the recessed portion
22. This recessed portion 21 has a size allowing the integrally
bonded member 10 to be just fitted therein, and entire surfaces of
the circuit pattern forming metal plates 13 face the window
portions 22 when the masking member 20 covers the integrally bonded
member 10. The window portions 22 are so positioned that the
exposed surfaces 16 of the outer peripheral edge portions in the
ceramic substrates 12 come in contact with a portion 23 surrounding
the window portions 22 in the masking member 20 to prevent the
passage of the treatment solution by this portion.
[0083] Incidentally, a material of the masking member 20 has to be
a material such as rubber, plastic, or metal having a high chemical
resistance to the etching solution, the plating solution, and the
like, and for example, silicon rubber, fluorine rubber,
polypropylene, Teflon, and so on can be suitably used.
[0084] Here, as shown in FIG. 4, the circuit pattern forming metal
plates 13 are exposed from bottom portions of the window portions
22 provided in the masking member 20. The protection pattern 15 of
a resist or the like having resistance to, for example, the etching
solution is provided on each of the circuit pattern forming metal
plates 13.
[0085] As shown in FIG. 1, in wet treatment according to this
embodiment, the integrally bonded member 10 covered with the
masking member 20 is set on an opening portion 32 provided in an
upper portion of a treatment tank 31 in a treating apparatus 30 for
wet treatment.
[0086] The integrally bonded member 10 is so structured, as
described above, that the circuit pattern forming metal plate 13 is
bonded on a part of the ceramic substrate 12 so as to expose the
outer peripheral edge portion of the ceramic substrate 12 to
constitute the metal-ceramic bonded member 14, and the ceramic
substrate 12 side of each of one or two or more metal ceramic
bonded member(s) 14 is bonded on the base plate 11.
[0087] The masking member 20 having the window portions 22 from
which the circuit pattern forming metal plates 13 are exposed
covers this integrally bonded member 10 so that the portion 23
surrounding the window portions in the masking member 10 comes in
contact with the exposed surfaces 16 of the outer peripheral edge
portions in the ceramic substrates 12 exposed in the metal-ceramic
bonded members 14.
[0088] Then, the integrally bonded member 10 covered with the
masking member 20 is set on the opening portion 32 provided in the
upper portion of the treatment tank 31 in the treating apparatus 30
with a circuit pattern forming metal plate 13 side thereof facing
downward.
[0089] A treatment solution 33, which is pooled in a bottom portion
of the treatment tank 31, is pressure-sent to an injection pipe 35
by a pump 34 to be injected upward from the injection pipe 35 and
after coming into contact with the circuit pattern forming metal
plates 13 to apply desired wet treatment thereto, it drops down to
the bottom portion of the treatment tank 31. This injection pipe 35
may be fixed in the treatment tank 31, but such a structure is
preferable that the injection pipe 35 is provided with a function
allowing it to rock in a horizontal direction, a vertical
direction, and so on since this structure can bring the treatment
solution 33 into contact with the circuit pattern forming metal
plates 13 uniformly from various directions so that uniform etching
without any variation depending on places can be achieved.
[0090] Next, an etching process as an example of a wet treatment
method for the integrally bonded member will be explained,
referring again to FIG. 1, FIG. 2, and FIG. 4.
[0091] First, the metal-ceramic bonded member 14 shown in FIG. 2 is
made by bonding the circuit pattern forming metal plate 13 on the
ceramic substrate 12. At this time, the circuit pattern forming
metal plate 13 is bonded so as to expose the outer peripheral edge
portion of the ceramic substrate 12, the exposed outer peripheral
edge portion having the width d (d=about 0.5 mm to about 1.5 mm),
as described above.
[0092] A desired number of thus formed metal-ceramic bonded members
14 each having the exposed surface 16 are prepared, and the ceramic
substrate 12 sides thereof are bonded on the base plate 11.
[0093] Incidentally, depending on cases, the bonding of the ceramic
substrate 12 and the circuit pattern forming metal plate 13 and the
bonding of the ceramic substrate 12 and the base plate 11 are
performed concurrently.
[0094] The circuit pattern forming metal plate 13 of each of the
metal-ceramic bonded members 14 bonded on the base plate 11 is
coated with the protection pattern 15 of a resist or the like
patterned after a predetermined shape. Various methods are
applicable as this coating method, but in the present invention,
since the circuit pattern forming metal plate 13 is not completely
coated with a laminate or a resist in advance, a highly productive
and low-cost printing method can be suitably applied in the case
of, for example, resist coating.
[0095] In this manner, the integrally bonded member 10 having a
desired number of the metal-ceramic bonded members 14 which have
been subjected to the resist coating is obtainable.
[0096] Incidentally, in a case when plating or the like is applied
to the entire surfaces of the circuit pattern forming metal plates
13 in wet treatment described later, the above-mentioned resist
coating or the like on the circuit pattern forming metal plate 13
is not necessary.
[0097] As shown in FIG. 4, when the obtained integrally bonded
member 10 is covered with the masking member 20, portions
corresponding to the circuit pattern forming metal plates 14 of the
integrally bonded member 10 are exposed from the window portions 22
of the masking member 20. At this time, the aforesaid exposed
surfaces 16 of the outer peripheral edge portions in the ceramic
substrates 12 come in contact with the portion 23 surrounding the
window portions 22 in the masking member 20.
[0098] Next, as shown in FIG. 1, the integrally bonded member 10
covered with the masking member 20 is set on the opening portion 32
provided in the upper portion of the treatment tank 31 in the
treating apparatus 30, with the circuit pattern forming metal plate
13 thereof facing downward.
[0099] Incidentally, the direction of setting the integrally bonded
member 10 relative to the treatment tank 31 may be a horizontal
direction, an oblique direction, and so on as desired as long as
the treatment solution does not stay in the window portions 22 of
the masking member 20, as will be described later.
[0100] Further, during this wet treatment, the integrally bonded
member 10 is preferably pressed with an appropriate pressure from
the base plate 11 side. This is because this pressurization
increases adhesiveness of the aforesaid portions where the exposed
surfaces 16 of the ceramic substrates 12 and the portion 23
surrounding the window portions 22 in the masking member 20 are in
contact with each other, and adhesiveness of portions where the
masking member 20 and the treatment tank 31 are in contact with
each other, thereby producing a state preventing the passage of a
liquid.
[0101] The pressing force may be appropriately determined, but it
is generally suitable to give a pressing force of about 0.05
kg/cm.sup.2 to about 0.3 kg/cm.sup.2 to the portions where the
masking member 20 and the treatment tank 31 are in contact with
each other.
[0102] When the setting of the integrally bonded member 10 on the
treating apparatus 30 has been finished, the treatment solution
(etching solution) 33 pooled in the bottom portion of the treatment
tank 31 is pressure-sent to the injection pipe 35 by the pump 34
and injected upward from the injection pipe 35 to be in contact
with the circuit pattern forming metal plates 13, thereby carrying
out an etching process. At this time, if the injection pipe 35 has
a rocking mechanism, the injection pipe 35 is preferably rocked.
The treatment solution (etching solution) 33 which has etched metal
portions drops to a lower part of the treatment tank 31 to be
pooled in the bottom portion.
[0103] The adoption of this structure enables continuous feed of
uniform and fresh treatment solution (etching solution) 33 to the
surfaces of the circuit pattern forming metal plates 13, and at the
same time, makes it possible to obtain an effect of preventing the
treatment solution (etching solution) 33 from staying on boundary
surfaces between the circuit pattern forming metal plates 13 and
the window portions 22 of the masking member 20.
[0104] This structure firstly aims at increasing etching efficiency
since the thickness of the circuit pattern forming metal plates 13
is far larger than that of a metal foil used for an ordinary
printed substrate.
[0105] It secondly aims at avoiding as much as possible such a
situation that the treatment solution (etching solution) 33 etches
undesired portions of the circuit pattern forming metal plates 13
as well due to its high corrosion behavior which is intended for
efficient etching of the circuit pattern forming metal plates 13
far thicker than a metal film provided on a conventional substrate
as described above.
[0106] However, even when the aforesaid structure is adopted, the
treatment solution (etching solution) 33 may possibly pass through
and enter from the boundary surfaces between the circuit pattern
forming metal plates 13 and the window portions 22.
[0107] Here, in the present invention, the portions where the
portion 23 surrounding the window portions 22 in the masking member
20 and the exposed surfaces 16 are in contact with each other have
sufficient adhesiveness to prevent the passage of a liquid through
these portions as described above, and in addition, even when the
treatment solution (etching solution) 33 enters, since neither the
ceramic substrates 12 nor the masking member 20 is corroded by the
treatment solution (etching solution) 33, the further passage
thereof can be prevented by these portions.
[0108] As a result, the corrosion of the base plate 11 by the
treatment solution (etching solution) 33 is avoidable.
[0109] When the etching process by the wet treatment is completed
in this manner and the circuit pattern forming metal plates are
turned into predetermined circuit patterns, the injection of the
treatment solution (etching solution) 33 is stopped, and the
boundary surfaces between the circuit pattern forming metal plates
13 and the window portions 22 of the masking member 20, and so on
are cleaned, thereby forming a circuit.
[0110] Further, when plating is performed, a protection pattern 15
patterned after a predetermined plating pattern is provided on each
of the circuit pattern forming metal plates 13 of the integrally
bonded member 10, similarly to the above-described etching process.
However, when the entire surfaces of the circuit pattern forming
metal plates 13 require the plating, the protection patterns 15 are
unnecessary.
[0111] The integrally bonded member 10 coated with the protection
patterns 15 is covered with the masking member 20, set on the
opening portion 32 provided in the upper portion of the treatment
tank 31 in the treating apparatus 30, and pressed with an
appropriate pressure from the base plate 11 side. This
pressurization continues while the plating is performed, similarly
to the etching process.
[0112] If this plating step is to be carried out by electroless
plating processing, it can be carried out by using the treating
apparatus 30 used in the above-described etching process and
changing the treatment solution 33 from the etching solution to a
series of treatment solutions for the electroless plating.
[0113] In this plating, the portions where the exposed surfaces 16
of the ceramic substrates 12 and the portion 23 surrounding the
window portions 22 in the masking member 20 are in contact with
each other also have sufficient adhesiveness and block the passage
of the treatment solution (plating solution) 33 so that plating of
the base plate 11 is avoidable.
[0114] When the etching process or the plating is completed in this
manner, the integrally bonded member 10 can be sent to a subsequent
step only by taking out the integrally bonded member 10 from the
masking member 20.
Embodiment 2
[0115] Next, (Embodiment 2) which is another embodiment according
to the present invention will be explained with reference to FIG.
5, FIG. 6A, and FIG. 6B.
[0116] FIG. 5 is a cross sectional view when the integrally bonded
member 10 explained in (Embodiment 1) is covered with a masking
member according to another embodiment, FIG. 6A is a perspective
view when wet treatment is applied to the integrally bonded member
10 covered with the aforesaid masking member in a treating
apparatus for wet treatment according to this embodiment, and FIG.
6B is a cross sectional view of FIG. 6A.
[0117] First, in FIG. 5, a masking member 40 has a substantially
equal shape to a square measuring box, similarly to the masking
member 20 explained in (Embodiment 1), and it accommodates the
integrally bonded member 10 having a predetermined number of the
metal-ceramic bonded members 14 bonded thereon. A circuit pattern
forming metal plate 13 side of the integrally bonded member 10
accommodated in the masking member 40 is exposed to the inside of
the treatment tank via window portions 22 of the masking member
40
[0118] Here, in this embodiment, the window portions 22 in the
masking member 40 are so arranged that a portion 23 surrounding the
window portions 22 is in close contact not with the outer
peripheral edge portions of the ceramic substrates 12 of the
integrally bonded member 10 but with the base plate 11, which
corresponds to a base member surrounding the ceramic substrates 12.
Further, in this embodiment, in order to press the integrally
bonded member 10 with an appropriate force, a back board 41 is
provided at the back of the base plate 11, the back board 41 and
the masking member 40 are fastened with fastening tools 42, and
these fastening tools 42 are fastened appropriately so that the
integrally bonded member 10 is pressed against the masking member
40. As a result, the integrally bonded member 10 and the masking
member 40 can be integrated while the integrally bonded member 10
is pressed against the masking member 40 with a desired force.
[0119] In this embodiment, the adoption of the above-described
structure makes it possible to obtain, in addition to the effect
explained in (Embodiment 1), an effect of preventing the treatment
solution from staying on boundary surfaces between the circuit
pattern forming metal plates 13 and the window portions 22 of the
masking member 40. As a result, an etching speed can be further
improved.
[0120] On the other hand, the possibility that the treatment
solution enters from the boundary surfaces between the ceramic
substrates 12 and the window portions 22 to etch the base plate 11
was concerned about in this embodiment. However, it has been found
out that actually, an amount of the treatment solution entering
from the boundary surfaces is only a little and insignificant when
the integrally bonded member 10 is in ordinary use.
[0121] Incidentally, a material of the masking member 40 has to be
a material such as rubber, plastic, or metal similarly to
(Embodiment 1), and for example, silicon rubber, fluorine rubber,
polypropylene, Teflon, and so on can be suitably used. As the
fastening tool 42, a bolt or the like made of a noncorrosive
material such as vinyl chloride, polypropylene, and Teflon can be
suitably used.
[0122] Next, in FIG. 6A and FIG. 6B, a treating apparatus 50 for
wet treatment according to this embodiment has an injection pipe 35
of a treatment solution 33 provided inside the treatment tank 51,
an opening portion 52 provided on an upper surface thereof parallel
to the injection pipe 35, and guide members 53 provided on both
sides of this opening. One or a plurality of integrally bonded
member(s) 10 described above, each covered with the masking member
40 and pressed against the masking member 40 by the back board 41
(not shown in FIG. 6A) and the fastening tools 42 (not shown in
FIG. 6A), is(are) set on the opening portion 52 via the guide
members 53 to be movable on the opening portion 52. The positional
relation between the opening portion 52 and the injection pipe 35
and the arrangement of injection holes provided in the injection
pipe 35 are so set that a sufficient amount of the treatment
solution 33 is fed to the surfaces of the circuit pattern forming
metal plates 13 (not shown in FIG. 6A) of the integrally bonded
member 10 via the window portions 22 (not shown in FIG. 6A) of the
masking member 40 which moves on the opening portion 52. The
treatment solution 33 injected from the injection pipe 35 is
finally pooled in a bottom portion of the treatment tank 51 to be
pressure-sent to the injection pipe 35 by a pump 34.
[0123] Further, as explained also in (Embodiment 1), the injection
pipe 35 may be fixed in the treatment tank 51, but such a structure
is preferable that the injection pipe 35 is provided with a
function allowing it to rock in a horizontal direction, a vertical
direction, and so on since this structure can bring the treatment
solution 33 into contact with the circuit pattern forming metal
plates 13 uniformly from various directions so that uniform etching
without any variation depending on places can be achieved.
[0124] Here, as the structure of the guide members 53, the
combination of a protruding portion and a recessed portion, the
combination of a rack and a pinion, the combination of a wheel and
a rail, the combination dependent on a magnetic absorption, and so
on can be considered, and from the viewpoint of leakage of the
treatment solution 33 and the like, the combination of the
protruding portion and the recessed portion is preferable.
[0125] Further, an opening of the opening portion 52 in the
treating apparatus 50 is preferably provided on the upper surface
of the treatment tank 51 in view of setting and the like of the
integrally bonded members 10, but the opening portion 52 may be
provided on a side surface of the treatment tank 51 as long as a
sufficient amount of the treatment solution 33 is fed to the
surfaces of the circuit pattern forming metal plates 13 of the
integrally bonded member 10.
[0126] Next, an etching process will be explained, similarly to
(Embodiment 1), as an example of a wet treatment method of the
integrally bonded member according to this embodiment with
reference to FIG. 5, FIG. 6A, and FIG. 6B.
[0127] First, the circuit pattern forming metal plate 13 is bonded
on the ceramic substrate 12 to form the metal-ceramic bonded member
14, similarly to (Embodiment 1), but the width d of the outer
peripheral edge portion of the ceramic substrate 12 need not be
provided if so desired. A desired number of thus formed
metal-ceramic bonded members 14 are prepared and the ceramic
substrate 12 sides thereof are bonded on the base plate 11.
[0128] Incidentally, depending on cases, the bonding of the ceramic
substrate 12 and the circuit pattern forming metal plate 13 and the
bonding of the ceramic substrate 12 and the base plate 11 are
performed concurrently.
[0129] A resist or the like patterned after a predetermined shape
is applied to the circuit pattern forming metal plate 13 of each of
the metal-ceramic bonded members 14 which are bonded on the base
plate 11, similarly to (Embodiment 1), to form the protection
pattern. As shown in FIG. 5, when the obtained integrally bonded
member 10 is covered with the masking member 40, portions of the
ceramic substrates 12 of the integrally bonded member 10 are
exposed from the window portions 22 of the masking member 40. At
this time, a portion of the base plate 11 surrounding the ceramic
substrates 12 is in contact with a portion surrounding the window
portions 22 in the masking member 40.
[0130] Next, the back board 41 is disposed at the back of the base
plate 11, the back board 41 and the masking member 40 are fastened
with the fastening tools 42, and the base plate 11 surrounding the
ceramic substrates 12 of the integrally bonded member 10 is pressed
against the portion 23 surrounding the window portions 22 in the
masking member 40. The pressing force may be determined
appropriately, but it is generally suitable that the pressing force
of about 0.05 kg/cm.sup.2 to about 0.3 kg/cm.sup.2 is given to the
portion where the masking member 40 and the treatment tank 51 are
in contact with each other. Thus, the integrally bonded member 10
covered with the masking member 40 is made.
[0131] A desired number of the integrally bonded members 10 each
covered with the masking member 40 are made, which are set
successively on the opening portion 52 provided in the upper
portion of the treatment tank 51 in the treating apparatus 50 shown
in FIG. 6A and FIG. 6B, via the guide members 53, with the circuit
pattern forming metal plates (not shown) thereof facing
downward.
[0132] When the setting of the integrally bonded members 10 on the
treating apparatus 50 has been finished, the treatment solution
(etching solution) 33 pooled in the bottom portion of the treatment
tank 51 is pressure-sent to the injection pipe 35 by the pump 34
and injected upward from the injection pipe 35 to come into contact
with the circuit pattern forming metal plates 13, thereby
performing the etching process. At this time, if the injection pipe
35 has a rocking mechanism, the injection pipe 35 is preferably
rocked. Meanwhile, the integrally bonded members 10 on the treating
apparatus 50 are subjected to the etching process for a
predetermined time while being moved on the opening portion 52, and
the etching process of the plural integrally bonded members 10 can
be performed successively.
[0133] When the etching process by the wet treatment is thus
completed, the integrally bonded members 10 each covered with the
masking member 40 are removed from the guide members 53, the
boundary surfaces between the circuit pattern forming metal plates
13 and the window portions 22 of the masking members 40, and so on
are cleaned, and plating which is a subsequent step is applied to
the circuit pattern forming metal plates 13 as desired, similarly
to (Embodiment 1).
Embodiment 3
[0134] Next, (Embodiment 3) as still another embodiment according
to the present invention will be explained with reference to FIG. 8
to FIG. 10.
[0135] FIG. 8 is a cross sectional view when the integrally bonded
member 10 explained in (Embodiment 1) is covered with a masking
member 60 according to still another embodiment, FIG. 9 is a cross
sectional view when an integrally bonded member 10' provided with
fins is similarly covered with the masking member 60, and FIG. 10
is a cross sectional view of the masking member taken along the
arrow A in FIG. 8 and FIG. 9.
[0136] First, in FIG. 8, the masking member 60 has a base 61 in
which substantially no deformation occurs even when being given a
load, a predetermined number of elastic members 62 provided at
predetermined places of the base 61, a plate-shaped first pressing
portion 63 which is resiliently supported on the base 61 by the
elastic members 62 and deforms according to a load of a loaded
place, and a plate-shaped second pressing portion 64 which is
provided on the first pressing portion 63, deforms according to the
load similarly to the first pressing portion 63, and is excellent
in liquid sealing.
[0137] In the masking member 60, the base 61 has a substantially
equal shape to a square measuring box similarly to the masking
member 20 explained in (Embodiment 1) or has a plate shape, and has
a predetermined number of window portions. The window portions in
the same size and at the same positions as the window portions of
the base 61 are provided also in the first pressing portion 63 and
the second pressing portion 64 to form window portions 22 of the
masking member 60. The integrally bonded member 10 in which a
predetermined number of metal-ceramic bonded members 14 are bonded
is disposed on the second pressing portion 64, and the position and
size of the window portions 22 match the position and size of the
metal-ceramic bonded members 14. As a result, the circuit pattern
forming metal plates 13 of the integrally bonded member 10 disposed
in the masking member 60 are exposed to the inside of the treatment
tank 31 of the treating apparatus 30 via the window portions 22 of
the masking member 60. Meanwhile, the window portions 22 are in
contact with the base plate 11 corresponding to a base member
surrounding the metal-ceramic bonded members 14 while being in
contact with the ceramic substrates 12. Here, in order to press the
integrally bonded member 10 against the masking member 60 with an
appropriate force, a back board 41 is provided at the back of the
base plate 11, the back board 41 and the masking member 60 are
fastened with fastening tools 42, and the fastening tools 42 are
appropriately fastened.
[0138] In this embodiment, the adoption of the above-described
structure brings about an effect that undulation on a surface of
the base plate 11 on which the metal-ceramic bonded members 14 are
bonded can be coped with, in addition to the effects explained in
(Embodiment 1) and (Embodiment 2).
[0139] Here, explanation will be given on the undulation on the
surface of the base plate 11 on which the metal-ceramic bonded
members 14 are bonded.
[0140] As described above, in the integrally bonded member 10, a
desired number of the metal-ceramic bonded members 14 are bonded on
the surface of the base plate 11. With the expansion of application
of the integrally bonded member 10, the base plate 11 gets upsized
and the number of the metal-ceramic bonded members 14 provided
thereon is also increased. However, a thermal expansion coefficient
of the base plate 11 differs from that of the metal-ceramic bonded
member 14, and consequently, distortion due to the difference in
the thermal expansion coefficient between these members occurs when
the base plate 11 and the metal-ceramic bonded members 14 are
bonded on each other at a high temperature and are cooled to a room
temperature, and a force of this distortion sometimes causes the
undulation on the surface of the base plate 11.
[0141] The masking member explained in (Embodiment 1) or
(Embodiment 2) can sufficiently cope with small undulation of the
base plate 11, but it is sometimes difficult to cope with the
undulation when the undulation exceeds 50 .mu.m. Specifically, even
when the masking member is appropriately deformed by the pressing
force, gaps occur between the masking member and the metal-ceramic
bonded members 14, and the treatment solution enters from these
gaps. As a measure to cope with this situation, the use of a choice
material for the masking member can be considered, but in
consideration of cost and a physical change due to secular
deterioration of the choice material, the masking member 60 which
is differently structured was devised.
[0142] Referring back to FIG. 8 again, each of a predetermined
number of the elastic members 62 disposed at the predetermined
positions of the base 61 which does not exhibit substantially no
deformation even when the load is given thereto as described above
independently supports the first and second pressing portions 63,
64 in a resiliently manner, and therefore, the first and second
pressing portions 63, 64 are pressed against the base plate 11 so
as to deform along the undulation on the surface of the base plate
11.
[0143] Here, the fastening tools 42 fastening the base 61 and the
back board 41 are appropriately fastened to generate a desired
pressing force between the base 61 and the back board 41, and this
pressing force is transmitted to the first and second pressing
portions 63, 64 via resilient forces of the elastic members 62.
Then, the first and second pressing portions 63, 64 are
appropriately deformed by this pressing force so that the treatment
solution is sealed by the second pressing portion 64 even when the
undulation of the base plate 11 is large, which enables the
prevention of the treatment solution from entering the masked
portions of the integrally bonded member 10.
[0144] Next, in FIG. 9, a predetermined number of fins are provided
on a surface of a base plate 11' in an integrally bonded member 10'
having fins, the surface being opposite a surface on which metal
ceramic bonded members 14 are provided. In this case, such a
structure may be adopted that a back board 41' provided with
long-legged protruding portions 43' is fastened to the masking
member 60 using fastening tools 42 and the long-legged protruding
portions 43' are pressed against portions of the base plate 11'
where the fins are not provided. The adoption of this structure
enables the masking member 60 to be pressed against the integrally
bonded member 10' having the fins with a desired pressing force
without damaging the fins.
[0145] Here, preferable arrangement of the elastic members 62 in
the masking member 60 will be explained, using FIG. 10.
[0146] FIG. 10 is an example of providing the window portions 22 at
three places in the masking member 60. The window portions 22 are
provided at three places of the base 61, and twelve elastic members
62 are arranged so as to surround the peripheries of the window
portions 22. The fastening tools 42 for fastening the base 61 to
the back board 41 are provided on four sides of the base 61. Owing
to the arrangement of the elastic members 62 around the peripheries
of the window portions 22, the permeation of the treatment solution
into the masked portions of the integrally bonded member 10 due to
the undulation of the base plate 11 can be effectively blocked. The
arrangement frequency of the elastic members 62, which may be
appropriately determined depending on the size of the undulation of
the base plate 11, is preferably increased when the undulation is
large.
[0147] In FIG. 8 to FIG. 10, the base 61 is preferably rigid resin
such as rigid PVC or a thick plate made of corrosion resistant
metal since the base 61 is required to have an excellent chemical
resistance and suffer substantially no deformation even when a load
is given thereto. As the elastic member 62 disposed on this base
61, rubber, a spring, or the like is usable, but a plunger
constituted of a cylinder having a spring member therein can be
suitably applied. This elastic member 62 is preferably made of
resin or corrosion resistant metal since it is also required to
have chemical resistance. Further, as the plunger, a short plunger
having a reactive force of about 5 N to about 20 N is suitably
used.
[0148] Since a material deformable along the undulation of the base
plate 11 when receiving the pressing force of the elastic members
62, and chemical resistance are required for the first pressing
portion 63, the first pressing portion 63 is preferably made of
GFRP or the like which is a composite material of resin and glass
fiber. Since water repellency, resiliency, and chemical resistance
are required for the second pressing portion 64 in order to prevent
the intrusion of the treatment solution, various rubber members,
especially silicon rubber and the like are suitably used for the
second pressing portion 64. Incidentally, it is also preferable
that the first and second pressing portions are integrated when an
appropriate material is obtainable.
[0149] Similarly to (Embodiment 2), as the fastening tool 42, a
bolt or the like made of a noncorrosive material such as polyvinyl
chloride, polypropylene, or Teflon can be suitably used. Further,
instead of using the fastening tools 42, such a structure may be
adopted that an appropriate load (about 20 kgf) is given to the
integrally bonded member 10 to press it against the masking member
60.
[0150] In the foregoing description, (Embodiment 1), (Embodiment
2), and (Embodiment 3) according to the present invention are
detailed, but each of the steps in these embodiments is
exchangeable with each other. For example, it is possible that the
plural integrally bonded members each covered with the masking
member described in (Embodiment 1) or (Embodiment 3) are prepared,
and while an appropriate pressing force is given thereto, the wet
treatment is successively performed in the treating apparatus
described in (Embodiment 2). Further, also in the plating performed
after the etching process, it is possible to use the masking member
and the wet treatment equipment described in any of (Embodiment 1),
(Embodiment 2), and (Embodiment 3).
[0151] The masking member described in (Embodiment 1) is superior
in that the portions not requiring the wet treatment are not
subjected to the wet treatment, the masking member described in
(Embodiment 2) is superior in that the portions requiring the wet
treatment are subjected to the uniform wet treatment, and
(Embodiment 3) is superior in that the integrally bonded member
having large undulation is subjected to the wet treatment.
[0152] When the combination of any of the above was used, since the
treatment solution comes in direct contact with an object to be
processed, great reduction in the treatment time was achieved, and
in addition, the structure as the treating apparatus could be
simplified. As a result, reduction in initial cost and running cost
of the steps for manufacturing power module members and so on from
the metal-ceramic bonded members and the integrally bonded members
was achieved, which resulted in cost reduction of power modules
manufactured from the power module members and the power module
members provided with various kinds of electron devices.
EXAMPLE 1
[0153] A sample of the integrally bonded member was prepared which
was so structured that a base plate was made of aluminum having a
size of 150 mm.times.80 mm.times.0.4 mm and a purity of 99.99%, or
higher, three AlN substrates having a size of 40 mm
square.times.0.635 mm were bonded on this base plate, and aluminum
having a size of 38 mm square.times.0.4 mm and a purity of 99.99%
or higher was bonded on each of the AlN substrates as a circuit
pattern forming metal plate.
[0154] Surfaces of the circuit pattern forming metal plates of this
sample of the integrally bonded member were irradiated with UV
after coated with an etching resist ink by a printing method so
that an etching resist was provided on each of them, while the base
plate was subjected to no process.
[0155] Next, the sample of the integrally bonded member provided
with the etching resist thereon was covered with a masking member,
and the circuit pattern forming metal plates were exposed from
window portions of the masking member. Then, a back board was
provided at the back of the base plate, the back board and the
masking member were fastened with polyvinyl chloride bolts, and a
portion of the base plate surrounding the ceramic substrates of the
sample of the integrally bonded member was pressed against a
portion surrounding the window portions in the masking member.
[0156] The plural samples of the integrally bonded members each
covered with the masking member were prepared, set on guide rails
provided on an opening portion in an upper surface of a treating
apparatus, with a surface where the circuit pattern forming metal
plates were exposed facing downward, and moved successively on the
opening portion at a fixed speed. The etching time was set to 25
minutes each.
[0157] As an etching solution, an aqueous solution of iron chloride
at a liquid temperature of 35.degree. C. was injected from an
injection pipe at 1.0 kg/mm.sup.2.
[0158] As a result, the etching of the base plate after undergoing
the aforesaid etching process was on a level unobservable with
naked eyes.
EXAMPLE 2
[0159] A similar measurement was performed, using the same
conditions and apparatus as in the example 1 except that the
etching time was set to 30 minutes each and the liquid temperature
of the etching solution was set to 30.degree. C.
[0160] The result showed that the etching of the base plate after
undergoing the aforesaid etching process was on a level
unobservable by naked eyes.
COMPARATIVE EXAMPLE
[0161] Similarly to the example 1, a sample of an integrally bonded
member was prepared, and an etching resist was provided on a
surface of each of circuit pattern forming metal plates of this
sample of the integrated bonded member, while a base plate was
subjected to no process, and an etching process was performed using
the treating apparatus provided with the conveyer according to the
conventional art.
[0162] The composition and liquid temperature of an etching
solution were similar to those in the example 1. When an injection
pressure from an injection pipe was also set to the same value as
that in the example 1, the etching time of 40 minutes was
required.
[0163] The base plate after undergoing the etching process was
extremely etched and on a level unusable as a product.
[0164] The present invention relates to a wet treatment method of a
metal-ceramic bonded member of a base integral type which is so
structured that a metal-ceramic bonded member is bonded on a base
plate, the metal-ceramic bonded member being constituted of a
ceramic substrate and a circuit pattern forming metal plate bonded
on the ceramic substrate, the method comprising: having a masking
member cover the metal-ceramic bonded member of the base integral
type in which the circuit-pattern forming metal plate is bonded so
as to expose an outer peripheral edge portion of the ceramic
substrate, the masking member having a window portion from which
the circuit pattern forming metal plate is exposed; pressing the
masking member against an exposed surface of the ceramic substrate
so as to prevent a treatment solution for the wet treatment from
passing through a portion where the masking member and the exposed
outer peripheral edge portion of the ceramic substrate are in
contact with each other; and during pressing the masking member,
bringing the treatment solution for the wet treatment of the
circuit pattern forming metal plate into contact with the circuit
pattern forming metal plate. As a result of the above structure,
the contact of the treatment solution with the base plate is
avoidable, thereby eliminating the necessity of laminate coating or
resist coating onto the whole integrally bonded member and of a
correction step thereof.
* * * * *