U.S. patent application number 10/566227 was filed with the patent office on 2006-09-14 for device and method for electrolytically treating electrically insulated structures.
Invention is credited to Michael Guggemos, Franz Kohnle.
Application Number | 20060201817 10/566227 |
Document ID | / |
Family ID | 33039358 |
Filed Date | 2006-09-14 |
United States Patent
Application |
20060201817 |
Kind Code |
A1 |
Guggemos; Michael ; et
al. |
September 14, 2006 |
Device and method for electrolytically treating electrically
insulated structures
Abstract
In order to permit continuous electrolytic treatment of small
electrically conductive structures that are electrically insulated
against each other on electrically insulating foil material, a
device for electrolytically treating electrically conductive
structures on surfaces of workpiece (1) that are electrically
insulated against each other is provided, said device comprising:
a) at least one arrangement, comprising at least one electrode (6)
for contacting the work pieces (1) and at least one electrolysis
region in a respective one of which at least one counter electrode
(4) and the work pieces (1) are in contact with the processing
liquid, b) the at least one contacting electrode (4) being disposed
outside of the at least on electrolysis region and not being in
contact with the processing liquid and c) the at least one
contacting electrode (6) and that at least one electrolysis region
being spaced so close together that small electrically conductive
structures can electrolytically be treated.
Inventors: |
Guggemos; Michael;
(Stahnsdorf, DE) ; Kohnle; Franz; (Berlin,
DE) |
Correspondence
Address: |
John F McNulty;Paul & Paul
2900 Two Thousand Market Street
Philadelphia
PA
19103
US
|
Family ID: |
33039358 |
Appl. No.: |
10/566227 |
Filed: |
August 19, 2004 |
PCT Filed: |
August 19, 2004 |
PCT NO: |
PCT/EP04/09436 |
371 Date: |
January 27, 2006 |
Current U.S.
Class: |
205/137 ;
204/198 |
Current CPC
Class: |
C25D 7/0621 20130101;
C25D 17/005 20130101 |
Class at
Publication: |
205/137 ;
204/198 |
International
Class: |
C25D 5/00 20060101
C25D005/00; C25D 17/00 20060101 C25D017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 12, 2003 |
DE |
103 42 512.8 |
Claims
1. A device for electrolytically treating electrically conductive
structures on surfaces of work pieces (1) the structures being
electrically insulated against each other, by using a method
comprising continuously conveying the work pieces (1) on a
conveying path and in a direction of transport with the structures
being electrolytically treated thereby, said device comprising: a)
at least one arrangement, comprising at least one electrode (6, 14)
for contacting the work pieces (1) and at least one electrolysis
region in a respective one of which at least one counter electrode
(4) and the work pieces (1) are in contact with the processing
liquid, characterized in that b) the at least one contacting
electrode (6, 14) is disposed outside of the at least one
electrolysis region and is not in contact with the processing
liquid and c) the at least one contacting electrode (6, 14) and the
at least one electrolysis region are spaced so close together that
small electrically conductive structures can electrolytically be
treated.
2. The device according to claim 1, characterized in that
electrically conductive structures of 5 cm can electrolytically be
treated.
3. The device according to any one of the preceding claims 1-2,
characterized in that at least two contacting electrodes (6, 14)
are provided, at least one of them being disposed on one side of
the electrolysis region and the at least other one on the other
side of the electrolysis region.
4. The device according to any one of claims 1-2, characterized in
that the electrolysis region is so short that the electrically
conductive structures are in constant electrical contact with one
of the contacting electrodes (6, 14).
5. The device according to any one of the preceding claims 1-2,
characterized in that it further comprises at least one processing
module (M, M1, M2, M3, M4, M5, M6) containing the processing liquid
and the at least one counter electrode (4), the work pieces (1)
being conveyed there through in a horizontal direction of
transport, the at least one processing module (M, M1, M2, M3, M4,
M5, M6) comprising, on the entrance and on the exit side thereof
respectively, at least one passage for the work pieces (1) to enter
and to exit said module and the at least one contacting electrode
(6, 14) being disposed on the passages.
6. The device according to any one of claims 1-2, characterized in
that it further comprises at least one tank (12) containing the
processing liquid and the at least one counter electrode (4) and
that the conveying path leads via the surface of the processing
liquid into the tank (12), to the at least one counter electrode
(4) disposed within the processing liquid and from there, via the
surface of the processing liquid again, out of the tank (12), the
at least one contacting electrode (6, 14) being disposed on the
surface of the processing liquid.
7. The device according to claim 6, characterized in that the
conveying path repeatedly leads via the surface of the processing
liquid into the tank (12), through the liquid and via the surface
again out of the tank (12), being thereby turned round by deviating
means (18).
8. The device according to any one of the preceding claims 1-2,
characterized in that it comprises partition members (21) which
comprise passages and sealing members (7, 23) for passage of the
work pieces (1), the partition members (21) being disposed between
the at east one contacting electrode (6, 14) and the processing
liquid, said sealing members (7, 23) being disposed in such a
manner that processing liquid can be prevented from coming into
contact with the at least one contacting electrode (6, 14).
9. The device according to claim 8, characterized in that the
sealing members are selected from the group comprising squeezing
rollers (7), sealing lips (23) and scrapers.
10. The device according to, claim 8, characterized in that the at
least one contacting electrode (6, 14) is secured to the partition
walls (24).
11. The device according to any one of the preceding claims 1-2,
characterized in that the at least one contacting electrode (6, 14)
is selected from the group comprising rollers and brushes (14).
12. The device according to claim 11 characterized in that the
rollers (6) have such a small diameter and the spacing between the
longitudinal axis of the rollers (6) and the at least one
electrolysis region is so small that electrically conductive
structures of 2 cm can electrolytically be treated.
13. The device according to any one of the preceding claims 1-2,
characterized in that between the at least one counter electrode
(4) and the work pieces (1) is disposed an electrically
non-conductive ion-permeable coating (13).
14. The device according to claim 13, characterized in that the
coating (13) is disposed in so close proximity to the conveying
path that the work pieces (1) touch the coating (13) as they are
conducted past the at least one counter electrode (4), thus acting
as a seal.
15. The device according to any one of the preceding claims 1-2,
characterized in that the conveying path is inclined to the
horizontal.
16. The device according to claim 15, characterized in that rinsing
facilities are provided by means of which the at least one
contacting electrode (6, 14) can be continuously or intermittently
rinsed.
17. The device according to any one of the preceding claims 1-2,
characterized in that the at least one counter electrode (4) and
the at least one contacting electrode (6, 14) are elongate and are
oriented substantially parallel to the conveying path and normal to
the direction of transport.
18. The device according to any one of the preceding claims 1-2,
characterized in that the at least one contacting electrode (6, 14)
is cathodically polarized.
19. The device according to claim 18, characterized in that the at
least one counter electrode (4) is an insoluble anode.
20. The device according to claim 19, characterized in that the
anode (4) is a flood anode.
21. The device according to any one of the preceding claims 1-2,
characterized in that the at least one contacting electrode (6, 14)
and the at least one counter electrode (4) are disposed on a common
carrier frame (5).
22. The device according to any one of the preceding claims 1-2,
characterized in that it further respectively comprises at least
one first and one second storing facility for storing the work
pieces (1).
23. The device according to claim 22, characterized in that it
further comprises conveying members (18, 25) for conveying the work
pieces (1) through the device from the at least one first storage
facility to the at least one second storage facility.
24. A method for electrolytically treating electrically conductive
structures on surfaces of work pieces (1), the structures being
electrically insulated against each other, the method comprising:
a) continuously conveying the work pieces (1) on a conveying path
and in a direction of transport through at least one electrolysis
region, said region containing at least one counter electrode (4)
and processing liquid, and b) bringing the work pieces (1) into
contact with at least one contacting electrode (6, 14) outside of
the at least one electrolysis region, characterized in that c) the
at least one contacting electrode (6, 14) is prevented from
contacting the processing liquid and d) the spacing between the at
least one contacting electrode (6, 14) and the at least one
electrolysis region is adjusted to be so small that small
electrically conductive structures can be electrolytically
treated.
25. The method according to claim 24, characterized in that
electrically conductive structures of 5 cm can electrolytically be
treated.
26. The method according to any one of claims 24 and 25,
characterized in that the work pieces (1) are at first brought into
contact with a contacting electrode (6, 14), are then passed
through an electrolysis region and are then brought again into
contact with a contacting electrode (6, 14).
27. The method according to claim 26, characterized in that the
electrolysis region is chosen to be so short that the electrically
conductive structures are in constant electrical contact with one
of the contacting electrodes (6, 14) as they are being passed
through the electrolysis region.
28. The method according to any one of claims 24-25, characterized
in that the work pieces (1) are guided in a horizontal direction of
transport through at least one electrolysis region contained in a
respective one of the processing modules (M, M1, M2, M3, M4. M5,
M6), the work pieces (1) being conducted into the module through
(M, M1, M2, M3, M4, M5, M6) at least one passage located on the
entrance side thereof and being conducted out of said module (M,
M1, M2, M3, M4, M5, M6) through at least one passage located on the
exit side thereof, said work pieces (1) being electrically
contacted by means of at least one contacting electrode (6, 14)
prior to entering the module (M, M1, M2, M3, M4, M5, M6) and/or
after having exited said module (M, M1, M2, M3, M4, M5, M6).
29. The method according to any one of claims 24-25, characterized
in that the work pieces (1) are conducted via the surface of the
processing liquid contained in a tank (12), into said tank (12), to
the at least one counter electrode (4) disposed in the processing
liquid and from there, via the surface of the processing liquid,
out of said tank (12) and that the work pieces (I) are electrically
contacted by means of at least one contacting electrode (6, 14)
prior to being introduced into the liquid and/or after having
exited said liquid.
30. The method according to claim 29, characterized in that the
work pieces (1) are repeatedly conducted via the surface of the
processing liquid into the tank (12), through the liquid and via
the surface again out of the tank (12), being thereby turn round by
deviating means (18).
31. The method according to any one of claims 24-25, characterized
in that an electrically non-conductive ion-permeable coating (13)
is mounted between the at least one counter electrode (4) and the
work pieces (I).
32. The method according to claim 31, characterized in that the
work pieces (1) are conducted so close alongside the non-conductive
ion-permeable coating (13) that they touch the work pieces (1),
33. The method according to any one of claims 24-25, characterized
in that the conveying path is inclined to the horizontal and that
the at least one contacting electrode (6, 14) is continuously or
intermittently rinsed.
34. The method according to any one of claims 24-25, characterized
in that metal is deposited onto the work pieces (1).
Description
[0001] The present invention relates to a device and to a method
for electrolytically treating electrically conductive structures
that are electrically insulated against each other on surfaces of
strip form work pieces in conveyorized plating lines.
[0002] For manufacturing chip cards (smart cards), price tags or
identification tags for goods, foil-like plastic is utilized, the
electrically conductive structures required for the electrical
function desired being produced thereon.
[0003] Conventional methods utilize for example a copper coated
material from which the desired metal pattern is produced using an
etching process. In order to lower the cost of this method and to
permit manufacture of structures finer than those that may be
achieved with the etching process, there is an intention to produce
the metal structures using electrolytic deposition. Such a known
method for manufacturing antenna coils is described in U.S. Pat.
No. 4,560,445. According to this, the metal structure is produced
on a polyolefin film using a method sequence involving the
following method steps: swelling, etching, conditioning the plastic
material for subsequent adsorption of catalytically active metal,
depositing the catalytically active metal, printing a mask in the
form of a negative image, accelerating the catalytically active
compounds, electroless and electrolytic metal plating.
[0004] Processes for metal plating strips include inter alia
electroplating methods. For many years, what are termed
reel-to-reel processing equipments have been used for this purpose
as conveyorized plating lines, the material being conveyed
therethrough and brought into contact with the processing liquid
during transport. The tapes are electrically contacted for
electrolytic metal deposition. Contacting electrodes serve this
purpose. For electrolytic treatment, it is possible to dispose
either the two electrodes, meaning the contacting electrode and the
counter electrode, or the counter electrode only within the
processing liquid in the processing lines.
[0005] DE 100 65 643 C2 describes a device for electroplating or
for electrolytically etching conductive strip-form work pieces in
which both the contact rollers serving for establishing electrical
contact and the counter electrode are disposed within the bath. The
problem of such arrangements is that the contact rollers are also
metal plated within the bath so that there is a risk that the metal
deposited onto the contact rollers damages sensitive foils.
[0006] For the purpose of avoiding or reducing metal deposits on
cathodes within the electrolyte bath, WO 03/038158 A describes an
electroplating equipment for reinforcing of electroplating
structures that have already been configured to be conductive on a
substrate in a reel-to-reel equipment for strips in which an anode
and a rotating contact roller are located in an electrolyte bath.
On its side turned toward the substrate, the contact roller is
connected to the negative pole of a direct current source and on
the side turned away therefrom, to the positive pole of the current
source. This is made possible by segmenting the contact roller in a
manner similar to that of the collector of a direct current motor.
As a result, the metal deposited onto the contact roller during one
revolution of the roller during normal operation can be stripped
off by changing the potential toward anodic. A major disadvantage
of this method is that the contact rollers are subject to heavy
wear as a result of the permanent alternating operation of metal
plating and deplating. This is the reason why very complicated and
expensive coatings are to be used.
[0007] A basic disadvantage however is that only surfaces that are
conductive over their entire area may be electrolytically treated,
structures which are insulated against each other and are desirable
for producing for example antenna coils however not.
[0008] DE 199 51 325 C2 therefore discloses a device and a method
for the contactless electrolytic treatment of electrically
conductive structures that are electrically insulated against each
other on surfaces of electrically insulated foil material, in which
the material is conveyed on a conveying path through a processing
equipment while being contacted with the processing liquid. During
transport, the material is conducted past at least one electrode
arrangement, each consisting of a cathodically polarized electrode
and of an anodically polarized electrode, the cathodically
polarized electrode and the anodically polarized electrode being in
turn contacted with the processing liquid. A current source causes
current to flow through the electrodes and the electrically
conductive structures. The electrodes are thereby shielded from
each other in such a manner that substantially no electric current
is allowed to flow directly between the two oppositely polarized
electrodes. A disadvantage of the method described is that the
layer of metal deposited can only have a reduced coating thickness
since as a result of the electrode arrangement metal is deposited
on the one hand but is also, at least in parts, dissolved again on
the other hand as the work piece is conducted past the cathodically
polarized electrode.
[0009] As opposed to the previous electrode arrangements, U.S. Pat.
No. 6,309,517 describes a plating device for plating the entire
surface of planar work pieces such as printed circuit boards in
which the cathode is contacted outside of the electrolyte, metal
being allowed to deposit as long as the material is in contact with
the cathode and the electrolyte. For establishing electrical
contact outside of the electrolyte cell, contact rollers, brushes
or glides are used. The rollers are sealed toward the electrolytic
cell by means of sealing rollers. This device however is not suited
for processing strip form work pieces and insulated structures.
[0010] DE 100 65 649 A1 proposes a device for the electrochemical
reel-to-reel processing of flexible strips having one conductive
surface that has a cathodic contact roller located outside of the
electrolyte. Special anode rollers around which the strips are
wounded are rotatably disposed within the electrolyte. The anode
rollers are thereby provided with an ion-permeable, electrically
insulating layer that keeps the strips spaced a defined and as
small a distance as possible apart from the anode. It is not
possible to treat surfaces having structures that are electrically
insulated against each other though.
[0011] As a result, the known methods do not permit to
electrolytically treat surfaces with small structures that are
electrically insulated against each other and that are deposited on
an electrically insulated work piece in foil strip form in strip
processing or conveyorized lines.
[0012] The problem underlying the present invention therefore is to
avoid the disadvantages of the known electrolytic processing
devices and methods. More specifically it is an object of the
present invention to find a device and a method which permit
continuous electrolytic treatment of small electrically conductive
structures that are electrically insulated against each other on
surfaces of electrically insulating foil material. A further object
of the present invention is to find a method and a device which can
be used for manufacturing foil material equipped with such type
conductive structures and employed as a component of chip cards
that serve for example to mark and automatically identify and
distribute goods in distribution stations or as electronic identity
cards, e.g. for access control. Such type electronic components are
to be manufactured on an ultra large scale at very low cost. Still
another object of the present invention is to find a method and a
device which may be utilized for manufacturing printed circuit
foils in the printed circuit technique and printed circuit foils
having plain electric circuits such as for toys, in automotive
engineering or in communications electronics.
[0013] The present invention provides the device in accordance with
claim 1 and the method in accordance with claim 24. Preferred
embodiments of the invention are recited in the subordinate
claims.
[0014] It must be noted that, as used in this specification and the
appended claims, the singular forms "a", "an" and "the" include
plural referents unless the content clearly dictates otherwise and
vice versa. Thus, for example, reference to a plurality of work
pieces includes a single work piece, reference to "a contacting
electrode" includes reference to two or more of such contacting
electrodes, and reference to "an electrolysis region" includes
reference to two or more electrolysis regions. Further reference to
a work piece includes a foil strip, foil segments or panels and the
like.
[0015] The method and the device of the invention serve to
electrolytically treat more specifically small electrically
conductive structures that are electrically insulated against each
other on surfaces of electrically insulating strip form work
pieces, more specifically of plastic strips (plastic foils)
provided with such conductive structures. Such type structures have
dimensions of a few centimeters e.g., of 2-5 cm.
[0016] The work pieces can be processed on both sides (surfaces) or
on one side only. In the first case, suited provisions for
performing electrolytic treatment are to be made on both sides, in
the latter case, on one side only.
[0017] The method and the device of the invention may also be used
for through plating or metal plating e.g., holes in the work
pieces. Insulated structures on one side of the work pieces may for
example be contacted with insulated structures or e.g.,
semiconductor components such as capacitors or chips, provided on
the other side.
[0018] The device of the invention comprises at least one
arrangement comprising at least one contacting electrode for the
work piece and at least one electrolysis region. In the
electrolysis region, at least one counter electrode and the work
pieces are contacted with the processing liquid. The contacting
electrode is prevented from contacting the processing liquid. The
contacting electrode and the electrolysis region are spaced such a
small distance apart that small electrically conductive structures
that are electrically insulated against each other and are to be
processed on the surface of the electrically insulating foil strip
form work pieces can be electrolytically treated. Within a
processing line, several such electrode arrangements may be
disposed one behind the other in series. Several such type
processing lines may be connected in series.
[0019] The spacing (distance) between the contacting electrodes and
the electrolysis region is to be as small as possible considering
the size of the insulated structures. In determining the spacing
between the electrolysis region and the contacting electrode, the
spacing between the beginning of the electrolysis region and the
site on the contacting electrode that establishes sufficient
contact with the work pieces is essential. This spacing is to be
minimized. It should be chosen so that even electrically conductive
structures of for example 5 cm may still be electrolytically
treated with good results.
[0020] This arrangement of the contacting electrodes and of the
electrolysis region permits to reliably metal plate even small
structures that are electrically insulated against each other. The
smaller the spacing between the contacting electrodes and the
electrolysis regions, the smaller the differences in the coating
thickness between the end areas (as viewed in the direction of
transport) and the central areas of the structures which may be due
to the fact that the structures are in contact with the contacting
electrodes while being simultaneously in the electrolysis region
for only a determined distance of the conveying path through the
device of the invention. A layer that has the same thickness in the
end areas and in the central area may be achieved when the spacings
between the contacting electrodes in the device are so small that
the structures can always be electrically contacted by at least one
contacting electrode as the work pieces are conducted through the
line. This is only possible if the structures are relatively large
or if the spacings between the contacting electrodes are small. As
the object of the invention consists in metal plating structures
having dimensions of but a few centimeters as uniformly as
practicable, the spacing between the contacting electrodes should
not exceed a few centimeters either.
[0021] A particularly advantageous embodiment consists in providing
at least two contacting electrodes, one of them being disposed on
one side of a transport section leading through an electrolysis
region and the other one on the other side of said transport
section. In order to achieve the advantage of a very uniform
electrolytic treatment as mentioned, the transport section leading
through the electrolysis region may, in this case, be preferably
chosen to be so short that the electrically conductive structures
are in permanent electrical contact with one of the contacting
electrodes.
[0022] In principle, a plurality of embodiments for implementing
the principles mentioned herein above is conceivable. A
particularly preferred first embodiment consists in providing at
least one processing module containing the processing liquid and
the at least one counter electrode, the work pieces being conducted
therethrough in a horizontal direction of transport without
direction change. In this case, the work pieces may be conducted
either in a horizontal or in a vertical orientation, an inclined
orientation being also possible. The processing modules each
comprise at least one passage on the entrance side and one passage
on the exit side thereof for the work pieces to enter the
processing module and to exit said module. In this embodiment, the
contacting electrodes are disposed on the passages. The
electrolysis regions are located in the processing modules. This
embodiment permits to achieve a very compact arrangement of the
electrodes and of the electrolysis region that allows processing of
even very small structures. Several such type processing modules
may be disposed in series.
[0023] In another, second embodiment there is provided at least one
tank containing the processing liquid and the at least one counter
electrode. The conveying path on which the work pieces are
conducted passes through the surface of the liquid into the tank,
within the liquid to the counter electrodes and from there exits
the tank through the surface of the liquid. In this case, the
contacting electrode is disposed (in immediate proximity) to the
surface of the processing liquid without contacting the latter. The
closer to the surface of the liquid the contacting electrodes and
the counter electrodes are disposed in this case (the contacting
electrodes outside of the liquid and the counter electrodes within
the liquid), the better the possibility to also electrolytically
process very small structures. Thanks to this arrangement,
contacting electrodes may more specifically be disposed in
immediate proximity to the surface of the liquid at those sites at
which the conveying path traverses the surface of the liquid.
Inasmuch, the considerations made herein above apply. In placing
squeezing rollers or air knives in a substantially upward oriented
conveying path above the liquid surface level not far from a
direction change into the horizontal, entrained processing liquid
may be stripped off by means of the rollers or the air knives and
returned to the tank.
[0024] However, the contacting electrodes must be spaced a minimum
distance apart from the surface of the liquid in order to prevent
said electrodes from being brought into contact with the
liquid.
[0025] To achieve as intensive an electrolytic treatment as
possible, the conveying path in this embodiment may enter the tank
through the surface of the liquid, traverse the liquid, exit the
tank through the surface while passing through deviating means such
as deviating rollers or cylinders several times.
[0026] The minimum size of the insulated structures to be processed
is more specifically determined by the minimum spacing that is to
be achieved between the contacting electrode and the counter
electrode. The minimum spacing depends inter alia on the spatial
dimensions of the contacting electrodes as well as on the distance
separating the contacting electrodes from the electrolysis region.
It is therefore advantageous to configure the contacting electrodes
as rollers or as a plurality of reels that are arranged in a
closely spaced apart relationship on an axis, the rollers or reels
having a very small diameter so that the spacing between the
longitudinal axes of the rollers or of the reel electrodes and the
electrolysis region may be chosen to be very small. Thanks to the
compact arrangement that can thus be achieved, electrolytic
treatment of structures having dimensions on the order of 2 cm or
even less may be achieved.
[0027] The attempt of reducing the minimum spacing between the
electrodes by using for example round contacting electrodes that
are as small as possible is often marred by the resulting
mechanical instability of the contacting electrodes, more
specifically when elastic contacting materials are being used. This
problem may in any case be circumvented by using mechanically
stable pinch rollers or reels that are disposed so as to fit
against the contacting electrodes, thus stabilizing them, and at
need even pressing them slightly together.
[0028] Instead of rollers and reels, brushes or electrically
conductive, sponge-like devices that wipe the surface of the work
pieces can be used as contacting electrodes.
[0029] The contacting electrodes are pressed by gravity and/or by
the application of a spring force onto the surface of the work
piece.
[0030] When adjusting the spacing between the contacting electrode
and the surface of the liquid in the second embodiment, the
contacting electrode is not allowed to be brought into contact with
the processing solution. If the contacting electrode is for example
used as a cathode in an electrolytic metal deposition process, the
contacting electrodes must be protected against undesired
metallization. It has however been found out that the spacing
between the contacting electrodes and the surface of the processing
liquid cannot be kept constant in practice. As a result,
difficulties may arise when adjusting this spacing. These
variations in the spacing are due to changes in the surface level
of the processing liquid in the processing tank, said changes being
caused for example by air being blown into said tank. Further, the
liquid surface level may be lowered by evaporation or by processing
liquid being dragged out of the tank by the work pieces conveyed
through the processing liquid. On the other hand, the liquid
surface level can also increase when dragged out or replenished
processing liquid is returned to the tank.
[0031] To circumvent this problem, it has been found advantageous
to insert in the region of the surface of the liquid between the
contacting electrode and the processing liquid a partition member
that allows the work pieces to pass therethrough but protects the
contacting electrode from being wetted by the processing liquid. In
order for the work pieces to be allowed to be conducted into and
out of the processing liquid, this partition member must comprise
passage openings such as slots through which the work pieces may be
conducted. Such a partition member may for example be a suitably
shaped liquid cover plate in which such a slot has been formed.
Alternatively, two cover plates may be provided, said two cover
plates being closely spaced together so as to form the slot.
[0032] The electrode arrangements of the invention may further
comprise sealing members such as sealing walls with sealing lips
and/or scrapers for retaining the liquid in the processing tank.
Squeezing rollers may further be present, said rollers retaining
the liquid, for example when the foil is being removed from the
liquid, while reliably guiding the work pieces. Such type sealing
members may be provided both at the passages provided in the
processing modules in the first embodiment of the invention and in
the partition members of the second embodiment. Said sealing means
serve to retain as completely as possible the liquid within the
electrolysis region so that no remaining liquid is allowed, as far
as practicable, to get in touch with the contacting electrodes.
Several such squeezing rollers (sealing rollers) may also be
stacked one on top of the other so that they mutually seal during
rotation.
[0033] If it is not possible to reliably prevent the processing
liquid from getting into contact with the contacting electrodes,
processing liquid that has exited the electrolysis region and
reached the contacting electrodes may be removed by providing
continuous or intermittent washing or spraying. In order to
efficiently rinse the processing liquid off the contacting
electrodes, the work pieces may be transported in a plane that is
for example inclined to the horizontal at an angle of at least
5.degree., of about 70.degree. at most and preferably at about
15.degree.. Rinse liquid delivered to the contacting electrodes
quickly drains off so that efficient removal of the processing
liquid is made possible. Alternatively, processing liquid that has
exited the electrolysis regions can also be removed by air jets,
using air knives for example.
[0034] If the contacting electrodes are configured to be rollers,
the work pieces, when they are treated on one side only, can be
electrically contacted by means of a contacting roller and of a
confronting current-less roller (supporting roller). When a
conductive pattern is to be produced on both sides, the contacting
rollers are to be provided on either side of the work pieces.
[0035] It is advantageous to configure the contacting electrodes
and the counter electrodes to be elongate and to arrange them in
such a manner that they extend over the entire useful width of the
work pieces. For this purpose, they may more specifically be
disposed substantially parallel to the conveying path.
[0036] In the case of the second embodiment, the deviating rollers
may also be utilized for establishing an electrical contact.
[0037] Roller-shaped contacting electrodes may preferably be
manufactured from an elastic conductive material. This makes it
possible to transfer a very high current onto the surface of the
work pieces on the one hand and to reduce the spacing between the
contacting electrodes and the electrolysis regions on the other,
since the contact faces between the electrodes and the surface of
the work pieces that determine these spacings are not narrow
elongate areas as this is the case with rigid rollers but wide
areas instead. Possible elastic contacting materials are
metal/plastic composite materials, more specifically composite
materials formed from an elastic plastic material having a large
amount of electrically conductive fillers. They consist of
elastomers as a binder such as caoutchouc, silicone or other
elastic plastics that are electrochemically stable and of an
electrically conductive filler. The binders also include conductive
adhesives that will not fully cure as they are being used in the
electronics manufacturing sector. The electrically conductive
filler is admixed to such type materials during manufacturing. The
metal plastic composite is thus obtained.
[0038] The fillers, which are also called inclusion components,
preferably consist of metal in the form of powders, fibers,
needles, cylinders, spheres, flakes, felt and other forms. The
amount of filler relative to the entire contacting material amounts
up to 90% by weight. As the amount of filler increases, the
elasticity of the metal plastic composite decreases and the
electric conductivity increases. These two values are adjusted to
the application case of concern. All of the electrochemically
stable materials that are also electrically conductive are suited
for being used as a filler. Current fillers are for example
titanium, niobium, platinum, gold, silver, special steel and
electrocoal. Platinum plated, silver plated or gold plated
particles, such as spheres made from titanium, copper, aluminum or
glass, may be used for example.
[0039] As the distance between the counter electrodes and the
conveying path for the work pieces is adjusted to be as small as
possible in order to achieve uniform electrolytic treatment, a
metal layer of uniform thickness for example, even at high cathodic
current density, there is a risk of an electrical short being
created between the work piece and the counter electrode in the
event that these are brought into undesired contact. In order to
reliably avoid this risk, the counter electrodes may be provided
with an ion-permeable, electrically non-conductive coating (an
insulating layer) that is preferably soft and permeable to liquid.
The spacing between the counter electrodes and the work piece may
thus be minimized in that the counter electrodes with the
insulating coating are brought near the surfaces of the work piece
so that the coatings get in touch with the surfaces of the work
piece.
[0040] In the event that the spacing between the counter electrodes
and the conveying path is adjusted to be so small that the coatings
on the counter electrodes wipe over the work pieces as they are
being conducted past the electrodes, the coatings can preferably be
wedged between the surfaces of the work piece and of the respective
one of the counter electrodes. For this purpose, the coatings may
project more specifically beyond the gaps formed by the counter
electrodes and the surfaces of the work pieces, be thicker on the
side of the cell walls that is turned away from the electrolysis
region and thus protrude beyond the gap width and hold tight on the
outer sides of the cell walls.
[0041] In order to prevent processing liquid from exiting the
electrolysis region in the latter embodiment, lock chambers may
further be provided within the processing module, said chambers
being disposed directly before or behind the electrolysis region as
viewed in the direction of transport. As a result, further
partition walls are provided within the processing module, said
walls separating the electrolysis region from the lock chambers.
Accordingly, the lock chambers are defined by the partition walls
and by the cell walls. In this embodiment, the lock chambers may be
sealed against the outside by means of the sealing walls having
sealing lips described herein above.
[0042] In order to prevent particularly thin work pieces from
warping, the counter electrodes may for example be rotatably
carried with their surface rotating at the same speed as the
contacting rollers. The counter electrodes and the contacting
electrodes may for example be motor driven with the work pieces
being rolled on the anodes, so that they also serve as conveying
members. The counter electrodes may be configured in different
ways. They may be formed as a plate or as an expanded metal.
Various types of counter electrodes may be combined. In order to
prevent depletion of active chemical substances at the surface of
the work pieces, fresh electrolyte may continuously be fed from the
interior of a counter electrode. Therefore, counter electrodes made
of expanded metal are preferred. This makes it possible to work at
high cathodic current densities without burns occurring during
electrolytic deposition.
[0043] In the event of electrolytic metal deposition, the
contacting electrode is cathodically polarized and the counter
electrode anodically (anode). Both soluble and insoluble anodes may
be used as counter electrodes. Round flood anodes or anode rollers
made of insoluble metal about which, in the second embodiment of
the invention, the work pieces are being wound and thereby turned
round may for example be used. Flood anodes comprise a hollow space
into which processing liquid may be pumped and out of which the
liquid may then be forced under pressure through openings in the
anode shell. The to be treated surfaces of the work pieces may thus
continuously be efficiently supplied with fresh processing liquid.
The dimensions of the anodes are preferably the same as those of
the work pieces.
[0044] If the device in accordance with the invention is utilized
for electrolytic metal deposition in the first embodiment, the
anodes e.g., flood anodes, in the processing liquid may be
configured to be elongate and oriented substantially normal to the
work pieces. In a particularly advantageous embodiment, the work
pieces may be conducted past a non-conductive, preferably soft,
liquid and ion-permeable coating provided on the anode without an
electrical short being created. This arrangement is provided in the
processing modules mentioned herein above that may be equipped, in
addition to the anodes, with electrolyte feed and discharge lines.
In order to seal the module against leakage of liquid, it is
provided with walls on all sides, said walls being for example
provided with passage openings, preferably slots, for the work
pieces. These walls provided with slots are disposed on the
entrance and on the exit side of the module and additionally
comprise the aforementioned sealing members. The sealing members
prevent greater amounts of electrolyte from escaping from the cell
and thus prevent metal to deposit on the cathodic contacting
elements. The sealing members may for example be sealing walls with
sealing lips that wipe over the work pieces without destroying
them. The liquid is thus prevented from exiting the module. If
particularly sensitive foils are to be processed, the elastic
sealing lips may be combined with sealing rollers. The diameter of
all of the rollers must be kept as small as possible in order to
permit processing of the small conductive insulated structures the
length of which ranges between 30 and 45 mm and less. The lower
limit for the diameter is dictated by the mechanical stability
required for the rollers being pressed against the work pieces.
[0045] In order to reliably provide a particularly compact
construction with minimal spacings between the counter electrodes
and the contacting electrodes, the contacting electrodes and the
counter electrodes can be accommodated as compact units on common
carrier frames.
[0046] The device in accordance with the invention is preferably a
component part of strip processing lines comprising each at least
one first and one second storage facility e.g., storage drums, for
storing the work pieces. Such type processing lines often further
comprise conveying members for conveying the work pieces through
the processing line from the at least one first storage facility to
the at least one second storage facility. Additionally, means for
guiding sensitive work pieces so that they keep a precise straight
course, for example lateral guide rollers and means for modifying
the position of the conveying reels, may be provided. For this
purpose, sensors may be provided along the conveying path, said
sensors continuously registering the position of the outer edge of
the work pieces and modifying the means for conveying and/or
guiding the foil upon detection of nonpermissible deviations.
[0047] The device is more specifically suited for depositing metal
on thin work pieces in strip form such as foils. Such type foils
may for example consist of polyester or polyolefin and of the
derivatives thereof, more specifically of polyethylene and
polyvinyl chloride (PVC). The foils may have different thicknesses
ranging for example from 15 to 200 .mu.m; PVC foils for example may
have a thickness of up to 200 .mu.m, depending on the application
case.
[0048] The device as claimed may more specifically be utilized for
manufacturing coil shaped structures on plastic foil material. Such
type coil shaped structures are used as antennas that are utilized
for contactless data transmission on a data carrier (Smart Cards).
Carriers comprising such type antennas may for example carry an
integrated circuit that is electrically wired with the antenna so
that electric pulses generated in the antenna are sent to the
integrated circuit where they are stored for example or the data
received by means of the antenna are processed as an electrical
signal.
[0049] Signal processing permits to convert the data supplied,
taking for example into consideration other data already stored,
the thus obtained data being in turn stored and/or delivered to the
antenna. These data, which are then transmitted by the antenna, can
be received in a receiving antenna so that the data emitted may for
example be compared to the data received by the antenna on the data
carriers. Such type data carriers may for example be utilized in
goods logistics and in retail trade e.g., as contactless readable
price tags or identification tags on goods, further as person
related data carriers such as ski passes and identity cards for
access control or as identification means for automotive
vehicles.
[0050] Further application fields of the foils provided with the
electrically insulated metal structures are for example the
manufacturing of simple electric circuits such as for toys or wrist
watches, in automotive engineering or in communications
electronics. These materials may further be utilized for active and
passive electromagnetic screening of apparatus or as screening grid
materials for buildings as well as on textiles for clothing.
[0051] The data carriers can be made from foils such as polyester
foils, polyolefin foils or polyvinyl chloride foils, on which the
electrically isolating structures have been electrolytically
produced, using the device of the invention. For this purpose, the
foils provided with metallized structures and manufactured using
the device are divided, according to the structure patterns
produced thereon in multiple printed panels, into discrete foil
segments corresponding to the size of the respective data carriers.
The integrated circuits may then be deposited onto the foil
segments and the metal structures electrically connected to the
integrated circuit deposited. A bonding process may more
specifically be utilized for this purpose. The integrated circuits
can be deposited not only in the form of a chip that has not yet
been provided with a carrier, but may also be deposited onto a
carrier such as a TAB carrier and placed onto the foil. Once the
integrated circuit has been electrically contacted, the foil
segment can be processed into the finished data carrier, said
segment being further laminated with another foil so as to form a
card with the antenna being welded therein.
[0052] More specifically, the electrically isolating structures on
the data carrier can be manufactured in the following manner:
[0053] The foil material, which is preferably in strip form and has
for example a thickness ranging from 20-50.mu. and a width of 20
cm, 40 cm or 60 cm, is provided on a storage drum around which the
foil is wound.
[0054] At first, the strip is provided with the structure to be
produced in that for example an activator varnish or an activator
paste is printed onto the surface of the foil. For this purpose,
said varnish or paste may for example contain a noble metal
compound, more specifically a palladium compound, preferably an
organic palladium complex. The varnish or paste moreover contains a
binding agent as well as further current constituents such as
solvents, dyes and thixotropic agents. The varnish or paste are
printed preferably by means of a roller onto the foil conducted
past said roller, more specifically with an offset, a gravure or a
lithographic printing process. For this purpose, the varnish or
paste is transferred from a reservoir onto a dispenser roller, from
the dispenser roller onto the printing roller and from there onto
the foil. Excess varnish or excess paste is removed from the
dispenser roller and from the printing roller using suited
scrapers. The printing roller may for example be coated with hard
chromium. The foil is pressed against the printing rollers by means
of a soft counter roller ("soft roller") for efficient inking. In a
station following the activator printing station, the ink printed
on the foil is dried. For this purpose, the strip form foil
material is conveyed through a drying path that is for example
formed from IR radiators or hot air ductors or that may also
comprise UV radiators if the binding agent in the activator varnish
or the activator paste is to dry reactively under the action of UV
radiation (preferably without solvent). These drying apparatus are
preferably disposed in a drying tunnel through which the strip form
material is conveyed. After having passed the drying station, the
strip form material reaches another strip storage facility that may
more specifically be formed from a drum. On its way from the first
storage drum from which the material is unwound to the second drum
on which the material is recollected, said material is guided and
stretched over reels (reel-to-reel process).
[0055] The strip form foil that has been printed with the activator
varnish or with the activator paste is first electrolessly and then
electrolytically metal plated in order to form the metal
structures.
[0056] For this purpose, the foil that has been printed with the
activator varnish or paste is unwound from the storage drum and
conducted through various consecutive processing stations of a
processing line, the strip form material being guided over
(deviating) reels and stretched (reel-to-reel method). In
principle, it is also possible to convey the strip form material
directly from the printing process to the wet-chemical treatment
without any further intermediate storing of the material.
[0057] In a first treating step the printed material is transferred
into a reductor that usually is a strong reducing agent in an
aqueous solution such as sodium boron hydride, an amino borane such
as dimethyl amino borane or a hypophosphite. In the reductor, the
oxydated noble metal contained in the varnish or the paste is
reduced to metallic noble metal, for example to metallic palladium.
After reduction, the strip is fed to a rinsing station where excess
reductor is water rinsed. A spray sink is preferably utilized for
this purpose. Next, a very thin layer of copper (of 0.2-0.5 .mu.m
thick) is electrolessly deposited onto the activator structures.
Copper deposition onto the structures is initiated by the noble
metal nuclei formed in the reductor, no copper being deposited onto
the non printed areas. A current bath containing formaldehyde as
well as tartrate, ethylene diamine tetraacetate or
tetrakis-(propane-2-ol-yl)-ethylene diamine may be utilized as the
copper bath. After copper plating, the strip form material is
conveyed to a rinsing station in which excess copper bath is
stripped off by spray rinsing with water.
[0058] Next, the strip form material is fed to the device of the
invention in which the now electrically conductive structures are
selectively coated with further copper. All of the known
electrolytic copper plating baths can be used for electrolytic
copper deposition, for example baths containing pyrophosphate,
sulphuric acid, methane sulfonic acid, amido sulfuric acid or
tetrafluoroboric acid. A particularly suited bath is a sulfuric
acid bath that may contain copper sulfate, sulfuric acid and small
amounts of chloride as well as additives such as organic sulfur
compounds, polyglycolether compounds and polyvinyl alcohol. The
sulfuric acid bath is preferably operated at a temperature near
room temperature at as high as possible a cathodic current density.
If the speed at which the foil strip is conveyed through the device
of the invention is 1 m/min, a cathodic current density of for
example 10 A/dm.sup.2 (active structure surface) could be adjusted
so that copper be deposited at a rate of about 2 .mu.m/min. With a
line of about 2.5-7.5 m in length, a copper layer of from 5-15
.mu.m thick can be deposited in this way.
[0059] Electric current can be supplied to the foil strip and to
the anodes in the device in accordance with the invention in the
form of direct current or of pulsed current. The latter is
advantageous for producing as high a current density as possible
since a copper layer exhibiting good properties (high surface
quality such as gloss, lack of roughness, uniform coating
thickness, good ductility, electric conductivity) can still be
deposited under these conditions. For this purpose, what is termed
reverse pulsed current is preferably utilized, i.e., a pulsed
current that comprises both cathodic and anodic current pulses. In
principle, unipolar pulsed current is of course also advantageous.
Using reverse pulsed current, the pulse heights of the cathodic and
anodic current pulses, the respective pulse widths and at need the
interpulse pauses as well are optimized in order to optimize the
deposition conditions.
[0060] Since electrolytic copper plating is performed using
insoluble anodes in the device of the invention, copper ions cannot
be subsequently dissolved by electrolytically dissolving copper
anodes. In order to maintain the concentration of copper ions in
the deposition solution, compounds of a redox system, more
specifically Fe.sup.2+ and Fe.sup.2+ compounds such as FeSO.sub.4
and Fe.sub.2(SO.sub.4).sub.3 are preferably added to the bath. The
Fe.sup.2+ ions contained in the bath oxidize at the insoluble anode
to form Fe.sup.3+ ions. The Fe.sup.3+ ions are transferred to
another tank containing metallic copper pieces (regenerating
tower). In the regenerating tower, the copper pieces oxidize under
the action of the Fe.sup.3+ ions to form Cu.sup.2+ and Fe.sup.2+
ions. As the two reactions (anodic oxidation of the Fe.sup.2+ ions
to form Fe.sup.3+ ions and oxidation of the copper pieces to form
Cu.sup.2+) proceed while concurrently, the concentration of copper
ions in the deposition solution can be kept largely constant.
[0061] After the foil strip has been passed through the metal
plating device of the invention, the material is again conducted to
a spray sink in which excess deposition solution is rinsed off.
Then, the strip material is transferred to a device in which it is
contacted with a passivation means that is intended to prevent
copper from tarnishing. Prior to winding the strip form foil
material onto another storage drum, the material is dried in a
drying station. For this purpose, the apparatus utilized may be
similar to those used for drying the activator varnish or the
activator paste.
[0062] The work stations utilized for performing the method steps
mentioned are equipped with suited guide and transport reels or
rollers as well as with apparatus for processing the processing
liquids such as filter pumps, dosing stations for chemicals, as
well as with heating and cooling systems.
[0063] The invention will be explained with reference to the Figs.
The Figs. show:
[0064] FIG. 1 a cross-sectional side view of a horizontal
processing line in accordance with the present invention in a first
embodiment in two variants;
[0065] FIG. 2 a cross-sectional side view of a single processing
module of a horizontal processing line in the first embodiment;
[0066] FIG. 3 a cross section of a half of a single processing
module of the horizontal processing line in accordance with FIG. 1
as viewed in the direction of transport;
[0067] FIG. 4 a cross-sectional side view of a single module of a
horizontal processing line in accordance with the present invention
in a first embodiment in another variant;
[0068] FIG. 5 a cross-sectional side view of a horizontal
processing line in accordance with the present invention in a
second embodiment;
[0069] FIG. 6 a cross section through the horizontal processing
line in accordance with FIG. 5 in a detailed solution;
[0070] FIG. 7 a detail of the horizontal processing line of FIG.
6;
[0071] FIG. 8 a cross-sectional side view of the horizontal
processing line in accordance with the present invention in the
second embodiment in another variant;
[0072] FIG. 9 a cross-sectional side view of a modified
implementation of the horizontal processing line of FIG. 8.
[0073] For closer description of the Figs. it is assumed that metal
is deposited onto strip form foils in the devices in accordance
with the invention and that cathodically polarized contact means
and anodes employed as counter electrodes are provided for the
purpose. Alternatively, the device can of course be utilized for
carrying out other cathodic treatment processes as well. Further,
the device in accordance with the invention may of course also be
utilized for carrying out anodic processes, for example for anodic
etching, chromatizing or anodizing (for example anodic electrolytic
oxidation). In this case, the strip form foil is anodically
polarized. A cathode is utilized as a counter electrode.
[0074] In the Figs. described herein after, like numerals have the
same meaning.
[0075] FIG. 1 illustrates a first embodiment of the device in
accordance with the invention. The size of the device shown in the
Fig. may more specifically approximately match the actual size of
the device. This means that the discrete modules M in the device
have, as viewed in the direction of transport, a length of a few
centimeters if electrically isolating structures respectively
having dimensions on the order of a few centimeters are to be
treated. Viewed in the direction of transport, the length of a
single module M may for example be 4.5 cm. The length of the
various modules (in this context the reader is referred to size L
in FIG. 2) depends on the size of the structures on the foil strip
1. The width of the discrete modules M depends on the width of the
foil 1 to be processed. If for example a foil strip 1 having a
width of 60 cm is processed in the device, the discrete modules M
must also have a width on this order. As a result, the modules M
are preferably elongate processing devices that extend
substantially normal to the direction of transport (direction of
transport denoted by an arrow in FIG. 1) over the entire width of
the foil 1.
[0076] The foil 1 is preferably provided in the form of a strip
which is unwound from a reel that has not been illustrated herein
and which, after having been conveyed through the device of the
invention, is wrapped around another reel that has not been
illustrated either (reel-to-reel).
[0077] The processing modules M are disposed along the conveying
path of the foil 1 leading through the device so that the foil 1 is
allowed to be conveyed through one module M after the other. The
number of modules M depends on the processing time required in the
discrete modules M: if a very thick copper layer is for example to
be deposited e.g., a layer of 5 .mu.m thick, with the foil strip 1
being intended to be conveyed at high speed through the device in
accordance with the invention, e.g., at a speed of 2 m/min, about
110 modules M having an active length of 4.5 cm are needed to be
disposed behind each other if copper is deposited at a cathodic
current density of 10 A/dm.sup.2 (2 .mu.m Cu/min). The term "active
length" of a module M is to be construed as the length of the
region within the module M in which metal is deposited onto the
foil 1 conveyed therethrough.
[0078] The device in accordance with the invention illustrated in
FIG. 1 consists of a collecting tank 12 in which there are disposed
three processing modules M. The collecting tank 12 consists of a
tank bottom and of two vertical side walls extending parallel to
the conveying path on which the foil strip 1 is being conveyed,
said walls extending respectively in front of and behind the plane
of the drawing and parallel to the direction of transport. Walls
are also provided at the two vertical end sides, said walls being
horizontally slotted for allowing the foil strip 1 to enter and
exit the collecting tank 12. This is shown in FIG. 1 on the left
hand side and on the right hand side respectively of the collecting
tank 12.
[0079] The foil strip 1 enters the collecting tank 12 through the
horizontal slot provided in the entrance wall on the left side wall
thereof and is conveyed through the collecting tank 12 in the
horizontal direction and in a horizontal orientation. The foil
strip 1 can be guided normal to the direction of transport so as to
be slightly inclined relative to the horizontal in order to aid the
liquid in flowing off the surface of the foil strip 1 over the
lateral side border of the strip 1 that is oriented parallel to the
direction of transport. The foil is conveyed through three
processing modules M that are disposed behind each other in the
direction of transport. After the foil strip 1 is conveyed through
the last module M, it exits the collecting tank 12 through the
horizontal exit slot provided in the exit wall.
[0080] The foil strip 1 is advanced within the collecting tank by
means of transport means and is also guided thereby. The transport
means may for example be the contact rollers 6 and the sealing
rollers 7 that will be both described in closer detail herein after
if these rollers are motor driven. In addition to these rollers,
other transport means that have not been illustrated herein may be
provided such as transport wheels that are secured to motor driven
axes that extend over the conveying path substantially normal to
the direction of transport or transport rollers that are disposed
in the same manner. The transport wheels on the axes may be
distributed over the entire width of the foil strip 1 or only be
disposed in the border region of the foil strip 1 for example. In
order to guide the strip 1 so that it is exactly parallel to the
direction of transport, the transport means may also be slightly
deviated from the conveying path or from the preferred axis
direction normal to the direction of transport in order to ensure
level guidance of the strip 1 on a straight line. Sensors that are
not shown in the Fig. and that continuously detect the precise
position of the strip permit to modify the orientation of the
transport and/or guide rollers in order to permanently keep the
foil on the same conveying path.
[0081] Processing liquid running off the processing modules M is
allowed to accumulate in the lower part of the collecting tank 12.
The liquid level in the collecting tank 12 is labeled with
reference numeral 15.
[0082] The discrete modules M in the device can be configured to be
identical or different. In the present case they are of identical
configuration.
[0083] Each processing module M comprises a top and a bottom
portion that are respectively disposed above and beneath the plane
of transportation of the foil strip 1. The walls of the modules M
are indicated at 10. These two portions form an upper electrolytic
cell 2 and a lower electrolytic cell 3 that are filled with
processing liquid. The two portions are built according to
substantially the same principle. Both portions comprise anodes 4
that are oriented toward the plane of transportation and are
disposed parallel to the plane of transportation on either side
thereof. In the modules M the anodes 4 are secured to the module
housing by means of suited holders 5. On the faces of the anodes 4
located on this side as viewed from the plane of transportation,
ion-permeable coatings (insulating layers) 13 are provided for
preventing contact between the foil strip 1 and the anodes 4.
Without the coatings 13, this could easily happen because the
spacing between the anodes 4 and the foil strip 1 is preferably
chosen to be very small. This small spacing permits to largely
prevent non uniform electrolytic treatment at different sites on
the electrically conductive structures so that a relatively high
current density can be adjusted.
[0084] Within the modules M, there is the processing liquid that is
supplied via electrolyte feed lines 11 to the inner volumes of the
two portions of the modules M. As a result, the strip 1 located in
the modules M and the anodes 4 are contacted with the processing
liquid so that an electric current is allowed to flow between the
anodes 4 and the structures on the strip 1 that are electrically
insulated against each other.
[0085] In order to electrically contact the structures that are
electrically insulated against each other, the foil strip 1 is
electrically contacted in accordance with the invention outside of
the electrolytic cells 2, 3. By electrically contacting the strip 1
very close to the region on the strip 1 in which the anodes 4
provide a largely homogeneous electrical field (electrolysis
region), the structures on the foil 1 that are electrically
insulated against each other can be electrically contacted with
contact means while they still or already are within the regions
mentioned. This makes continuous electrolytic treatment
possible.
[0086] In the case shown in FIG. 1, contact rollers 6 are provided
downstream and upstream of the left module M and contact brushes 14
downstream and upstream of the right module M, these contact
rollers and brushes being employed as contact means and being
oriented substantially normal to the direction of transport and
over the entire width of the conveying path.
[0087] The contact rollers 6 can more specifically be metal
rollers, for example rollers the outer contacting surface of which
is made of special steel or of copper or rollers having an
electrically conductive, elastic surface. In the latter case, the
surfaces of the rollers 6 may for example be provided with an
elastic plastic coating that is rendered electrically conductive by
insertion of metallic particles.
[0088] The contact brushes 14 can be fibers made from copper or
graphite for example that are secured on a brush base. The fibers
may additionally be electrically insulated at the fiber shaft.
[0089] To allow the current to flow from the contact rollers 6 or
contact brushes 7 via the structures that are electrically
insulated against each other and the processing liquid to the
anodes 4, a current source that has not been illustrated herein is
utilized, the poles of which are connected to the contact rollers 6
or the contact brushes 14 or to the anodes 4.
[0090] In the case shown in FIG. 1, the strip 1 is electrically
contacted by means of electric contact rollers 6 or contact brushes
14, with said rollers 6 and brushes 14 not coming into contact with
the processing liquid. For this purpose, the contact rollers 6 and
the contact brushes 14 are located outside of the regions of the
modules M that contain processing liquid.
[0091] Sealing rollers 7 are further provided, said sealing rollers
largely preventing processing liquid from exiting the inner volume
of the modules M and from reaching the contact rollers 6 or contact
brushes 14. For, if the contact rollers 6 or the contact brushes 14
were to come into contact with the processing liquid, metal could
be deposited thereon. This is not desirable. The sealing rollers 7
are preferably elastic and are pressed against the surfaces of the
foil strip 1. As a result, they tightly fit against the surfaces of
the strip 1. Like the contact rollers 6 and the contact brushes 14,
they are disposed normal to the direction of transport and
distributed over the entire width of the conveying path for the
foil strip 1.
[0092] Furthermore, elastic sealing walls 9 are provided for
sealing the module housing against exiting liquid. For this
purpose, the sealing walls 9 are secured to the end walls 10 of the
module housing so as to provide a liquid tight sealing, preferably
pressing tangentially against the sealing rollers 7. In the case of
the sealing rollers 7 being disposed downstream within a module M
and of the sealing walls 9, the latter are attracted toward the
sealing rollers 7 by the rotation of the same due to the mechanical
friction and the static pressure of the liquid within the
electrolytic cell, thus providing efficient sealing of the module M
against leakage of processing liquid into the liquid free space. By
contrast, in the case of the sealing rollers 7 and the sealing
walls 9 being disposed upstream, the sealing walls 9 would
continuously be lifted from the sealing rollers 7 by the rotation
thereof so that sufficient sealing against leaking liquid could not
be provided. Therefore, auxiliary sealing rollers 8 are
additionally provided in the entrance region of the modules M, said
auxiliary rollers being preferably configured to have an elastic
surface like the sealing rollers 7 and rolling on the sealing
rollers 7. In this case, the sealing walls 9 fit against the
auxiliary sealing rollers 8 and efficiently seal the module M
against leaking liquid.
[0093] On the sides of the modules M that extend parallel to the
direction of transport, sealing lips (not shown herein) are
provided for sealing against leaking processing liquid. Since there
are no contact means for electrically conductive structures in this
region, efficient sealing is not absolutely necessary, though.
[0094] The top portion of the modules M can be configured to be
removable for introducing the foil into the device. Corresponding
holding elements (not shown) mounted to the lower portion of the
module permit to securely retain the top module portion during
normal operation and to firmly anchor it using e.g., readily
releasable wing nuts.
[0095] FIG. 2 shows a cross section of a module M in a collecting
tank 12 that is filled to the bath surface level 15 with processing
liquid that has run off the surfaces. The foil strip 1 enters the
collecting tank 12 through a horizontal slot in the one end wall
thereof and first comes into electrical contact with the contact
brushes 14 via both sides of the material. Electric current is
supplied to the electrically conductive structures on the strip 1
via the brushes 14. The brushes 14 extend substantially over the
entire width of the strip 1 so that all the structures on the strip
1 can be supplied with current. It is important that all the
structures be touched by the brush fibers as they are conducted
past the brushes 14. As the structures extend in the direction of
transport, they can be in electrical contact with the brushes 14
while being at the same time located within the electrical field of
the anodes 4 in the electrolytic cells 2, 3.
[0096] Very close to the brushes 14 and downstream thereof there
are provided sealing rollers 7 that are disposed on either side of
the strip 1. Auxiliary sealing rollers 8 additionally roll on the
sealing rollers 7, sealing walls 9 providing a tangential seal. The
elastic sealing walls 9 are secured to the cell walls 10 of the
module M. Processing liquid is supplied from the collecting tank to
the inner volume of the module M via electrolyte feed lines 11 and
pumps and pipelines (not shown). Excess processing liquid is
returned to the collecting tank via electrolyte discharge lines 17
provided in the cell walls 10.
[0097] After having been conducted past the seal, the foil strip 1
enters the inner volume of the module M in which it is exposed to
the electrical field of the anodes 4 disposed above and beneath the
plane of transportation. The anodes 4 are made of expanded metal,
for example of platinum plated titanium. Ion-permeable coatings 13
are located between the plane of transportation and the anodes 4,
said coatings preventing an electrical short from developing upon
contact of the anodes 4 with the electrically conductive
structures.
[0098] After the foil strip 1 has been passed through the module M
it is conducted past another pair of sealing rollers 7 that
prevents liquid from exiting the module M. Sealing walls 9 that fit
tangentially against the sealing rollers 7 and are secured to the
cell end walls 10 additionally seal the inner volume against liquid
leakage. Once the strip has passed the sealing rollers 7 it is
brought into contact with further contact rollers 6. The structures
that are electrically insulated against each other and can no
longer be contacted by the contact brushes 14 as they are conveyed
through the module M are electrically contacted again as a result
thereof.
[0099] FIG. 3 is a cross sectional view of a half of the view
indicated at "A" in FIG. 1. Inasmuch, the reader is referred to the
elements mentioned in the description of FIG. 1 and labeled with
the corresponding reference numerals.
[0100] On either side of the foil strip 1 guided here in a
horizontal plane of transportation, anodes 4 that are also
horizontally oriented and mounted on anode holding devices 5 as
well as ion-permeable isolations 13 that directly fit against the
anodes 4 are shown in the module M which, in the sectional view, is
denoted by the cell walls 10. The anodes 4 and the foil strip 1
define electrolytic cells 2, 3.
[0101] Further, horizontally mounted sealing rollers 7 may be seen
in the front view, said rollers being mounted on bearings 16 in one
of the cell walls 10. A respective contour of the sealing rollers 7
is covered by the sealing walls 9 and is therefore shown in a
dotted line. The sealing walls 9 extend toward the plane of
transportation and tangentially fit against the sealing rollers 7.
They are secured to the cell end wall 10 so as to provide a liquid
tight seal.
[0102] The processing liquid is supplied from the collecting tank
12 to the inner volume of the module M via electrolyte feed lines
11 and (not shown) pumps and pipelines and is allowed to run off
via electrolyte discharge lines 17. The liquid that has run off
accumulates in the sump of the collecting tank 12 (which is
indicated by the bath surface level 15).
[0103] FIG. 4 shows another preferred embodiment of a module M in a
collecting tank 12. The view corresponds to the view shown in FIG.
2.
[0104] As contrasted with the module M shown in FIG. 2, the
ion-permeable coating 13 is in direct contact with the passing foil
strip 1. The coating 13 concurrently performs the function of
sealing the inner volume of the processing module M against the
contacting electrodes 14. In order to prevent processing liquid
from directly reaching the contacting electrodes 14 through the
coating 13, the inner volume of the module M is bounded by
additional inner partition walls 24. On these inner partition walls
24 the coating 13 is secured on the entrance and on the exit side
so as to be liquid tight. The coating 13 may additionally be
secured to the cell walls 10 that extend alongside the conveying
path. As the work piece 1 does not extend as far as the outermost
region of the inner volume of module M, this additional fixation is
not absolutely necessary.
[0105] Via electrolyte feed lines 11 the processing liquid is
delivered to the anodes 14 formed from expanded metal, which it
traverses before being supplied to the coatings 13. Since the
coatings 13 are formed from sponge-like or liquid absorbing
material, they can become saturated and establish an electrolytic
contact between the anodes 4 and the strip material 1. Excess
processing liquid can flow back to the collecting tank 12 in a
direction transverse to the direction of transport.
[0106] Since, thanks to the capillary forces and the squeezing, the
liquid is retained substantially within the isolating material 13
in the entrance and exit region of the inner partition walls 24,
there is a reduced risk that liquid exits the module M. Residual
amounts of liquid that can exit the processing module M are
discharged downward via the volume formed by the partition walls 24
and the cell wall 10 of the module on the entrance and on the exit
side through the electrolyte discharge line 17 into the sump of the
collecting tank 12. As a result sealing lips 23 suffice to keep the
contacting elements 14 largely free of liquid. On the exit side
(downstream), two sealing lips 23 can be provided on the wall 10 of
the processing module M, said sealing lips being secured both to
the inner and the outer wall surface 10 in order to prevent
processing liquid from exiting the module M as it is more easy for
the processing liquid to exit the module M there than in the
entrance region because of the forward movement of the strip 1. As
a result, the spacing provided between the contact brushes 14 (or,
in the alternative, of the contact rollers 6) and the electrolytic
cells 2, 3 is very small. In order to prevent the friction
resulting from the coating 13 coming into contact with the work
piece 1 from causing the strip 1 to elongate, transport rollers 25
can be provided before and behind each module M. To regulate the
pressure, more specifically in the lower module cells 3, control
valves can be mounted into the pipelines of the discharge lines 17,
said control valves adjusting the pressure to be constant within
the cells 2, 3 through sensors provided in said cells 2, 3.
[0107] As the insulating layers 13 continuously wipe over the foil
strip 1 and disturb the diffusion layer on the work piece 1, this
implementation variant permits to adjust particularly high current
densities.
[0108] FIG. 5 is a cross sectional side view through a horizontal
processing line in accordance with the present invention in a
second embodiment. The processing line comprises a collecting tank
12 in which there are disposed three processing modules M that are
identical in construction. The processing modules M are disposed
alongside the conveying path of the foil strip 1 through the device
so that the foil strip 1 is allowed to be conveyed through one
module M after the other. The discrete processing modules M
substantially consist of the contact rollers 6, the anodes 4
comprising an ion-permeable isolation 13, anode holders 5 and
processing liquid (electrolyte). The processing liquid fills the
collecting tank 12 to such an extent that the bath surface level 15
lies just underneath the contact rollers 6.
[0109] The rollers 6 are arranged in such a manner that, at the
deviating roller 18, which, like the contact rollers, can be motor
driven for assisting in transport, the substantially horizontally
fed foil strip 1 is conveyed into the first module M, being passed
in a vertical movement between the contact rollers 6 into the
processing liquid. The two sides of the foil strip 1 are
electrically contacted by the two contact rollers 6. The anodes 4
are configured to be flood anodes made of an insoluble metal from
the inner volume of which fresh electrolyte is continuously
supplied for the deposition process. The flood anodes convey the
foil strip 1 past the isolation 13 where it is metal plated before
being drawn out of the electrolyte while being contacted anew at
the other contact reels 6 located above the bath surface level 15.
After having been turned round by the other deviating reel 18, the
foil strip 1 is conveyed through the second module M and, after
having been turned round anew by the third deviating reel 18,
conducted through the third module M. After having been conducted
past the third module M, the foil is again turned round by means of
a fourth deviating reel 18 before being finally horizontally led
out of the processing line.
[0110] FIG. 6 illustrates a cross sectional detailed solution of
two modules M of the horizontal processing line in accordance with
FIG. 5, only one half of each module M being shown.
[0111] In this case, the device is characterized by the additional
component parts, namely the partition member 21 with slots and
sealing lips 23 (shown in FIG. 7) and the pinch rollers 22. These
component parts serve to protect the contact rollers 6 from the
processing liquid. The pinch rollers 22 serve to increase the
mechanical stability of the contact rollers 6, which are configured
to be particularly thin. The pinch rollers 22, which fit directly
against the contact rollers 6, can press these together when the
rollers 6 are elastic, thus making certain that the current is well
transmitted even in the case of contact rollers 6 having a very
small diameter. This in turn permits to further reduce the spacing
between the anode 4 and the contact rollers 6.
[0112] In a special embodiment, the pinch rollers 22 can also
perform the function of the counter electrode. For this purpose,
the rollers have for example a spiral coating that is not
illustrated in the Fig. and is deposited in the form of narrow
strips on the conductive anode surface of the roller shaped anodes
4. The spacings between the spiral helix remain exposed. The
coating, which is deposited like a spring, rolls on the contact
rollers 6, pressing them against the work pieces 1. Thanks to the
spiral shape, the screening effect of the coating, which is not or
but to a small extent ion-permeable, on the pinch rollers 22 acting
as anodes exerts its effect permanently on other sites of the work
pieces 1 and prevents them from being non-uniformly coated. The
same effect can be achieved using ring shaped isolations that are
mounted to the anodes so as to be offset from one module to the
other.
[0113] In order to protect the contact rollers 6 from being metal
plated by splashing processing liquid, the surface of the liquid is
completely covered by a partition member 21 comprising a slot
serving as a passage opening.
[0114] During electrolytic treatment the foil strip 1 is passed
through the schematically denoted anode 4 comprising an isolation
(not shown herein) in the first module M, the anode 4 almost
touching the contact rollers 6. The foil strip 1 is supplied from
the inner volume of the anodes 4 through the slot in the partition
member 21 directly to the contact rollers 6 without coming into
contact with the processing liquid outside of the anode 4 like in
FIG. 5. As a result, the amount of entrained processing liquid is
minimized. Then, the foil strip 1 is turned round at the deviation
roller 18 and conveyed into the second module M. It is thereby
electrically contacted again at the contact rollers 6 and
introduced through the slot in the partition member 21 into the
anode 4 for further metallization.
[0115] FIG. 7 shows a schematic detail of the detailed solution for
module M of the horizontal processing line of FIG. 6.
[0116] The foil strip 1 is passed between the contact rollers 6
that are spaced in close proximity to the anode 4 and between the
sealing lips 23 that are disposed at the slot of the partition
member 21. It can be seen that the partition member 21 is capable
of efficiently protecting the contact rollers 6 from the processing
fluid. The sealing lips 23 thereby prevent undesired liquid leakage
as a result of a varying bath surface level for example.
[0117] FIG. 8 illustrates a cross sectional lateral view of the
second embodiment of a horizontal processing line in accordance
with the present invention in another variant. The processing line
consists of a collecting tank 12 having three different modules M1,
M2 and M3 that are each characterized by various anode and cathode
arrangements.
[0118] The processing modules are disposed alongside the conveying
path of the foil strip 1 leading through the device so that the
foil strip 1 is capable of passing sequentially through the
discrete modules, starting with module M1. Deviating reels 18 are
disposed before and between the modules.
[0119] The foil strip 1 is introduced into the module M1 by means
of a deviating reel 18. The module M1 substantially consists of a
pivoted anode roller 4 having an ion-permeable isolation 13, the
anode 4 being partially immersed into the processing liquid. The
liquid surface level is indicated at 15. The coating 13 between the
anode roller 4 and the foil strip 1 serves for insulation and can
thereby be supplied with processing liquid provided from the inner
volume of the roller 4. The module M1 further includes a cover cap
20 that protects the contact roller 6 against being wetted with
processing liquid. On this cover cap 20 there are disposed,
upstream of the anode 4 as viewed in the direction of transport of
the foil strip 1, a single first contact roller 6 that is
electrically insulated against the anode 4, and downstream of said
anode 4 a second contact roller 6 that is electrically insulated
against said anode 4. Said module M1 is preferably used if the foil
strip 1 is to be metal plated on one side only. The anode holder 5
and the contact roller 6 are combined into one unit for a more
compact construction.
[0120] After metal plating has been completed, the foil strip 1 is
conveyed out of the module M1 and via a deviating reel 18 into the
second module M2. The module M2 comprises an anode arrangement
consisting of a pivoted anode roller 4 having an ion-permeable
isolation 13 and of a curved anode 4' also having an ion-permeable
isolation 13 that projects out of the liquid surface level 15 and
conforms to the orientation of the foil strip 1. Upstream and
downstream of the anode arrangement there are located two identical
contacting arrangements that are disposed on the cover cap 20 so as
to be electrically insulated against the anode 4. These
arrangements consist of a contact roller 6 and of a contact brush
14 located on the opposite side of the contact roller 6.
[0121] After the foil strip 1 has been plated on its two sides in
module M2, it is conveyed via a deviating reel 18 into the third
module M3. Module M3 is substantially similar to module M2. Contact
rollers 6 are used in lieu of the contact brushes 14, said contact
rollers being mounted on the same supporting arm as the anode 4''
against which they are electrically insulated. The shape of the
curved anode 4'' clearly conforms to that of the rotatable anode 4.
This module M3 constitutes a preferred embodiment if the use of
contact brushes is to be excluded since the contact between the
anode 4'' and the work pieces 1 is more uniform and longer than at
the anode 4', thus resulting in a more uniform coating. Upon
completion of the treatment in the third module M3 the foil strip 1
is conveyed out of the processing line via a deviating roller
18.
[0122] FIG. 9 illustrates a cross sectional side view of a variant
of the horizontal processing line of FIG. 8.
[0123] The identical modules M4 and M5 substantially resemble
module M3 shown in FIG. 9, the lower curved anode 4'' having been
dispensed with. The modules are suited for use in the cases in
which the foil strip 1 is to be coated on both sides. In the
modules M4 and M5, the contact rollers 6 are mounted to an anode
holder 5 so as to be electrically insulated.
[0124] The various embodiments described can also be combined in
other manners as those described herein above. The sealing member
with the sealing lips 23 shown in FIG. 7 may e.g., also be used in
the variant shown in FIG. 8 and in FIG. 9.
[0125] It is understood that the examples and embodiments described
herein are for illustrative purpose only and that various
modifications and changes in light thereof as well as combinations
of features described in this application will be suggested to
persons skilled in the art and are to be included within the
disclosure of the described invention and within the scope of the
appended claims. All publications, patents and patent applications
cited herein are hereby incorporated by reference.
REFERENCE NUMERALS
[0126] 1 work piece (foil strip) [0127] 2 electrolytic cell top
[0128] 3 electrolytic cell bottom [0129] 4 counter electrodes,
anodes [0130] 5 counter electrode holders, anode holders [0131] 6
contacting electrodes, contacting rollers [0132] 7 sealing rollers
[0133] 8 auxiliary sealing rollers [0134] 9 sealing wall [0135] 10
module wall, cell wall [0136] 11 electrolyte feed line [0137] 12
collecting tank [0138] 13 ion-permeable isolation [0139] 14 contact
brushes [0140] 15 bath surface level [0141] 16 sealing roller
bearing [0142] 17 electrolyte discharge line [0143] 18 deviating
roller [0144] 19 bearing surface for the upper anode holder cover
cap [0145] 21 partition member [0146] 22 pinch roller [0147] 23
sealing lip [0148] 24 inner partition wall [0149] 25 drive rollers
[0150] M, M1-M5 processing modules
* * * * *