DE102009004249A1 - Plant for single-sided strip-electroplated deposition of metallic function layers on substrate strip, comprises an electroplating module having a strip guide and an electrolyte container, a compressed air supply, and a transportation unit - Google Patents

Abstract

The plant comprises an electroplating module (2), which has a strip guide (6b) for horizontally guiding a substrate strip (1) through the electroplating module and an electrolyte container, a compressed air supply, and a transportation unit for the substrate strip. An anode (4) is arranged in the electrolyte container for strip-electroplating deposition and is designed to receive electrolytes, so that the electrolyte flows to an upper side of the guided substrate strip. The module has a plate, which is arranged in such a manner that the substrate strip is aligned with its upper side. The plant comprises an electroplating module (2), which has a strip guide (6b) for horizontally guiding a substrate strip (1) through the electroplating module and an electrolyte container, a compressed air supply, and a transportation unit for the substrate strip. An anode (4) is arranged in the electrolyte container for strip-electroplating deposition and is designed to receive electrolytes, so that the electrolyte flows to an upper side of the guided substrate strip. The module has a plate, which is arranged in such a manner that the substrate strip is aligned with its upper side parallel to the plate during the guidance. The plate contains air-guiding elements, through which compressed air (7) is conductible from the upper side of the plate to the lower side of the plate. The compressed air supply is designed to conduct the compressed air from the upper side of the plate to the lower side of the plate. An air bag forms itself in the guided substrate strip between the plate and the passing-through substrate strip. The module is implemented in two-parts, where a lower part comprises the electrolyte container and an upper part comprises the plate and the parts of the strip guide and air guide of the compressed air supply. The strip guide comprises two L-profiled rails, which are integrated into the upper part of the module and serve for laterally guiding the substrate strip. The L-profiled rails consist of high abrasion-resistant material. The upper part is removably fastened to the lower part by hinges. A maximum width of the guided substrate strip given by dimensioning the strip guide is less than or equal to the width of the anode. The electrolyte container has lateral openings for the flow of the electrolytes, which lie in the same horizontal plane as the substrate strip lying in the strip guide. The transportation unit comprises magnetic rollers and a convex plain bearing, which are arranged upstream and downstream to the module. The magnetic rollers and the plain bearing lie at the upper side of the guided substrate strip. The plain bearing consists of porous material, through which the compressed air is conductible, so that the air bag forms itself in the guided substrate strip between the plain bearing and the substrate strip. The plate has bores as air-guiding element, where the bores obliquely pass through the plate. The anode is formed from a central strip and two marginal strips, which are electrically insulated from each other and are connected at different electrical potentials.

Description

The The invention relates to a system for one-sided band galvanic deposition Metallic functional layers on a substrate tape, with a Electroplating module, which is a tape guide for horizontal guidance of the substrate tape through the electroplating module and includes an electrolyte container, in the one anode for the band galvanic deposition is arranged and designed is to receive an electrolyte such that the electrolyte can flow to an underside of the horizontally guided substrate strip.

State of the art and technological background

in the Contrary to the galvanic deposition of decorative surface coatings plays in the electrochemical deposition of functional layers the uniformity the layer thickness often a crucial role. For example, in the electrochemical Deposition of precursor layers ("Precursor" layers) for the CIGSS compound semiconductor of chalcopyrite solar cells on strips of thin sheet steel or other flexible metallic or metal coated sheet materials a layer thickness uniformity of +/- 2% required. The electroplated layers of copper, indium, Gallium, possibly also selenium combine in a subsequent one Tempering step to a semiconductor with a fixed, predetermined Stoichiometry. For local deviations of the layer thickness of the individual layers from the setpoint, the mixing ratio of the reactants deviates from stoichiometry, resulting in "impurities" of the chalcopyrite semiconductor and malfunctions the photovoltaic activity to the uttermost Failure of the solar cell leads.

Such Extreme demands on the layer uniformity can be achieved with "normal" galvanic Difficult to realize strip coating systems with vertical tape guide; it also exists here the problem of backside coating. to Achieving high uniformity more suitable are so-called wheel electroplating plants. Such Radgalvaniken (also referred to as Trommelvanvanik) are structurally significant consuming, so that the acquisition costs and the changeover times when changing the band clearly higher.

Known Furthermore, strip galvanic plants with horizontal strip guide have become structurally less expensive as wheel electroplating and the standard tape electroplating with vertical tape guide in terms of uniformity and re Avoiding a backside coating are superior however, they too do not achieve such extremely high uniformity requirements as for example, to the sequential precursor deposition CIGS solar cells.

at Bandgalvaniken in which the tape to be coated vertically through the plant is run, it is usual, by a special cathode construction and / or screens and shields the homogeneity to improve the deposition. At Radgalvaniken be dazzles with a customized hole pattern in front of the band mounted to one as possible to achieve homogeneous deposition.

Taking into account such, improving measures remain with the hitherto known strip electroplating, when they are used for the deposition of functional layers with high layer thickness uniformity, the following advantages and disadvantages:
In the case of belt galvanic systems with vertical belt guidance, additional measures must be taken to ensure that deposition on the back of the belt is avoided. This is achieved for example by masking the back with plastic film, which means a considerable additional effort and prevents the electrical contact of the tape on its back.

Further is not in band electroplating systems with vertical tape guide Ensure that the distance between the substrate tape and the Anode is strictly adhered to. Rather, the band may be due to the flow move through the electrolyte with little play; the changing one Anode distance leads but inevitably to fluctuations in the layer thickness.

Little the conditions are different in the previously known systems with horizontal tape guide. Here The belt is compressed by compressed air from above against the inflowing electrolyte pressed. Slight fluctuations in the pressure ratio lead to a bulging of the Bandes and thus to changes at the distance of the band to the anode, resulting in other deposition conditions in the band center, compared with its edges, leads.

1 shows in cross section a conventional plant for strip electroplating. The ribbon 1 is guided horizontally and from below by a tributary 8a into the electroplating module 2 incoming electrolyte flowed. To a back coating of the tape 1 to avoid, the tape becomes 1 on the upper side by compressed air 7 pressed against the inflowing from below the electrolyte. The disadvantage is that a not completely exact adjustment of the air pressure on the Elektrolytanströmung to a Durchwölbung of the flexible band 1 what causes inhomogeneities the result of the coating, because the distance to the anode four changes. This is even more true, the wider the band and the smaller its thickness.

In the usual strip galvanic with horizontal guidance continues to be the band 1 laterally through a U-shaped groove 6a in the electroplating module 2 held, so that on both sides an edge zone of the band 1 remains uncoated, which is undesirable in many cases.

Furthermore, it is important for a homogeneous coating that in the conventional system, the anode four although close to the substrate band 1 can be arranged, but is less wide, as the substrate tape 1 , At the in 1 shown system design with U-shaped tape guide, it is not possible, the anode four as wide as the entire substrate tape 1 train.

Finally, there is the accessibility of the band 1 and anode four limited in systems of the usual type, because the inserted over its entire length in the lateral guide slots band 1 access to the anode four prevented and because the tape 1 must be inserted or removed frontally.

How out 1 can be seen, lies the electrolyte drain 8b at a slightly lower level than the bottom of the substrate tape 1 , so that gas bubbles, which arise during the electrolytic deposition, as well as compressed air bubbles, which under the band 1 Well, accumulate on the underside of the belt and prevent uniform coating.

It is thus obvious that the previous design bandgalvanischer Systems with horizontal tape guide, although they are opposite Ribbon electroplates with vertical band guide better uniformities generates, some weak points or improvement possibilities exhibit.

at a Radvanvanik arise additional problems when the coated side of the tape is not touched or passed over rollers may. The band guide This is very complicated, which requires increased tension power. This and the frequent Deflection, the band is subjected to strong bending, resulting in a replacement of the Layers or can lead to deformations of the tape.

specially in the mentioned Radgalvaniken a change of the band is very consuming. Due to the many deflections and loops remains a much longer tape length in the Investment.

Summary of the invention

The The present invention has set itself the task of per se already comparatively good layer thickness homogeneity with horizontal tape guidance and at inflowing from below Electrolyte to further improve, so that an extremely high layer thickness uniformity, for example, according to the requirements of a solar cell, achieved while avoiding the aforementioned disadvantages.

The Invention is based on a system for one-sided bandgalvanischen Deposition of metallic functional layers on a substrate tape, with a galvanic module, a tape guide for horizontal guidance of Substrate band comprises by the electroplating module and includes an electrolyte container, in the one anode for the band galvanic deposition is arranged and designed is to receive an electrolyte such that the electrolyte can flow to an underside of the horizontally guided substrate strip. The inventive system is characterized in that the electroplating module comprises a plate, which is arranged so that the substrate strip during the guidance by the electroplating module is aligned with its top parallel to the plate, and the Contains plate spoiler elements, by the compressed air from a top of the plate to the bottom the plate is conductive. The system according to the invention further comprises a compressed air supply, which is designed for compressed air from the top of the plate through the To guide plate, so that when inserted substrate strip between the plate and the continuous substrate tape an air cushion formed.

On the side of the substrate strip opposite the side to be coated, a plate made of perforated or porous material, adjacent to the upper side of the substrate strip, is thus provided over the entire length of the galvanic, electrolyte-filled module and over the full width of the substrate strip. Through holes or pores in the plate air is pressed through, which forms an air cushion on top of the substrate strip with 3 functions:
First, the tape lies on a defined surface; a bulge or a variation of the distance between the cathode and anode is thus no longer possible.

Secondly the compressed air forming the air cushion will escape laterally on the belt, whereby penetration of the electrolyte on the tape top and the unwanted Top coating is prevented.

Third, the frictional resistance between the back plate and the back plate decreases Band, so that a lower tensile stress is sufficient and a smooth belt movement is possible, resulting in the longitudinal direction of the belt to a more uniform coating.

Prefers is that the electrolyte tank of the Electroplating module lateral openings for the Outflow of the electrolyte has, in the same horizontal Level lie as the substrate strip lying in the tape guide. In other words, the outlet of the electrolyte is in exactly that same horizontal plane laid in which the to be coated Band is located. This will cause bubbles of gas to form in the galvanic process on the tape form as well as air bubbles from the side of the band swelling compressed air to the side rinsed be or drain with the electrolyte.

Further is preferred if the electroplating module is designed in two parts, with a lower part, which comprises the electrolyte container, and an upper part, the the plate and parts of the tape guide and airflow the compressed air supply includes. The tape guide preferably comprises two L-profile rails, which are integrated into the upper part of the electroplating module and to the side guide serve the inserted substrate tape. The L-profile rails are preferably made Made of a highly abrasion-resistant material.

Accordingly, an L-profile, preferably made of glass or ceramic or another smooth and abrasion-resistant material (such as CERAN) is preferably used instead of the usual tape guide in the housing wall of the plastic galvanic module. This profile is embedded in the usually made of plastic upper part of the galvanic module. This measure achieves several advantages:
As with the previously known tape guide in U-shaped grooves of the housing base, the band can not emigrate to the side here. At the same time, however, unlike a conventional tape guide in a U-profile, the entire band underside is coated without edge galvanic. At the same time, however, the air cushion located behind the belt is offered a lateral limit.

Secondly can The usually sharp edges of the tape are not in the plastic cut the module top, which in extreme cases to tape stop or destruction lead the electroplating module would. Should the back Air cushions fail, so is the frictional resistance between the guide profiles and the continuous band still low, because the friction between the volume and glass / ceramic is smaller than between tape and plastic.

thirdly let yourself the band from the two lateral L-profiles just down remove while a band guide must be fed by lateral U-profiles frontally.

A further advantageous measure is the training of the electroplating module as the upper and lower part, the upper part lid-like formed and in the plane of the tape guide with side hinges is pivotally mounted on the lower part. A band change or a Access to the anode in the lower part of the module is thus by simple Swinging up the upper part possible. In other words, the upper part is preferably by hinges hinged attached to the lower part.

Furthermore, it is preferred if a predetermined by the dimensioning of the tape guide maximum width of the inserted substrate tape is less than or equal to the width of the anode. For a good uniformity of the coating in strip electroplating plants is of crucial importance that the anode is in the immediate vicinity of the strip and has at least the same, but if possible a larger width. How out 1 this is not possible in the previous concept of galvanic systems with horizontal tape guide; inevitably the effective anode area is limited by the U-guide of the band. This is no longer the case in the inventive leadership of the band between L-profiles, which are embedded in the lid of the electroplating module. Accordingly, the anode can be increased compared to conventional systems.

The Plant also preferably includes a transport unit for the substrate strip, which arranged before and behind the electroplating magnet rollers includes, which bear against the top of the inserted substrate strip. The transport unit can continue in front of and behind the electroplating module arranged, convex moldings include, which bear against the underside of the inserted substrate strip, the shaped bodies from a porous material exist, by the compressed air is conductive, so that at inserted substrate tape between the molding and the continuous substrate tape an air cushion trains.

Of the aforementioned embodiment Accordingly, the idea of a tape guide using magnetic rollers respectively before and after the galvanic coating module. A touch The coated hinge side is made by using magnetic rollers avoided. The magnetic rolls keep the ribbon at a low level Wrap angle and upcoming tension reliable in Position. Thus, this improvement serves the overall goal, one extremely uniform band coating.

The same thing applies to the use of air bearings, porous, flowed through by compressed air bearings on the coated side of the tape: Obviously, contact rollers, also magnetic rollers for power supply, on the underside of the band because of their small contact area as such not sufficiently suitable to enter high currents. Therefore, will between two magnetic rollers, which are designed as electrical contacts are, a plain bearing mounted on the Gutseite of the tape so that the wrap angle of the band at the contact rollers considerably elevated. The plain bearing consists of a porous material, so that Application of compressed air an air cushion between the band and the Sliding bearing is formed, which prevents contact. It understands itself, that such a convex plain bearing as a porous, air-flow role could be trained and not just for support the power supply, but also for contactless Deflection of the strip running direction can be used.

A see further preferred embodiment before that the plate has as an air guide holes, the aslant pass through the plate, d. H. the holes are against the vertical running inclined to the edge of the tape. This is intended to be achieved Be sure that the compressed air is not just perpendicular to the belt down suppressed, but possible moisture on the top of the tape targeted to Blown away side by the air flow a horizontal Component has. Furthermore Thus, the formation of a laminar air flow is supported and thus stabilizing the air cushion.

Finally is preferred that the anode of at least one middle and two Edge strip is formed, which are electrically isolated from each other and to which various electrical potentials are connected can. This allows a particularly uniform coating over the entire width of the tape to be ensured.

Brief description of the drawings

The Invention is described below in an embodiment and with reference to the associated drawings explained in more detail. It demonstrate:

1 An electroplating module of a conventional system for the strip galvanic deposition of metallic functional layers on a substrate strip;

2 An electroplating module of a system according to the invention for the strip galvanic deposition of metallic functional layers on a substrate strip; and

3 Details of a transport unit of a system according to the invention for the strip galvanic deposition of metallic functional layers on a substrate strip.

Detailed description the invention

2 shows a cross-section of an embodiment according to the invention of a plant for tape galvanic deposition of metallic functional layers on a substrate strip 1 in the area of a galvanic module 2 , According to the technology for systems with homogeneous coating, the tape 1 guided horizontally and from below by the electrolyte by an electrolyte inflow 8a incident flow. To a defined edition of the tape 1 to ensure the tape lies 1 on a porous perforated plate 5 , and this is done with injected compressed air 7 flows through. This forms. between the perforated plate 5 and the substrate tape 1 a carrying air cushion. At the same time, a back coating of the tape 1 avoided.

In the strip galvanic system according to the invention with horizontal guidance, the band 1 through a lateral tape guide 6b limited. The guide is designed as an L-shaped profile made of abrasion-resistant material, such as CERAN. This geometry allows the use of anodes four that are wider than the substrate band 1 are; in addition, the tape 1 now coated over its entire width.

Easy accessibility of the substrate tape 1 and the anode four is about a division of the electroplating module 2 in a shell 2 B and a lower part 2a reached. Both parts 2a . 2 B are about a hinge 3 connected, which directly in the level of an electrolyte drain 8b located. By this measure, in conjunction with the use of the back perforated plate 5 and the recessed in the lid lateral L-guide the bath guide 6b , is the introduction or removal of the substrate tape 1 considerably simplified.

How out 2 it can be seen, lies the electrolyte drain 8b now exactly at the same level as the underside of the substrate strip 1 , so the gas bubbles, which arise during the electrolytic deposition, as well as compressed air bubbles, which under the band 1 well over the electrolyte drain 8b be dissipated.

3 shows a longitudinal section through an electroplating module according to the invention 2 including two magnetic rolls each 9 , formed as contact rollers, and porous, convex plain bearings 10 into which compressed air 7 is introduced, in front of and behind the electroplating module 2 are arranged. Here are the magnet rolls 9 and the porous, convex and air-flow bearings 10 arranged so that the wrap around the magnet rolls 9 through the band 1 is big enough. At the same time it remains between the band through the air cushion 1 and plain bearings 10 the deflection contactless.

Claims (11)

Apparatus for the single-sided tape galvanic deposition of metallic functional layers on a substrate strip, comprising a galvanic module comprising a tape guide for horizontal guidance of the substrate tape by the electroplating module and containing an electrolyte container in which an anode for the tape galvanic deposition is arranged and which is adapted to receive an electrolyte, such that the electrolyte can flow to an underside of the horizontally guided substrate strip, characterized in that the electroplating module comprises a plate which is arranged so that the substrate strip is aligned parallel to the plate during the guidance by the electroplating module with its upper side, and the Plate containing air guide elements, is guided by the compressed air from an upper side of the plate to the underside of the plate; and the system further comprises a compressed air supply adapted to direct pressurized air from the top of the plate through the plate such that when the substrate band is sandwiched between the plate and the continuous substrate band, an air cushion is formed. Plant according to claim 1, characterized in that the electroplating module is made in two parts, with a lower part, that the electrolyte container includes, and a top that holds the plate and parts of the tape guide and air ducting the compressed air supply includes. Plant according to claim 2, characterized in that the band guide two L profile rails includes, which are integrated in the upper part of the electroplating module and to the side guide serve the inserted substrate tape. Plant according to claim 3, characterized in that the L-rails consist of a highly abrasion-resistant material. Installation according to one of claims 2 to 4, characterized that the upper part hinged by hinges attached to the lower part is. Installation according to one of claims 2 to 5, characterized that a predetermined by the dimensioning of the tape guide maximum width of the inserted substrate strip less than or equal to the width of Anode is. Plant according to one of the preceding claims, characterized in that the electrolyte container of the electroplating module has lateral openings for the outflow of the electrolyte lying in the same horizontal plane like that in the band guide lying substrate band. Installation according to one of the preceding claims, characterized in that the system includes a transport unit for the substrate strip, which arranged before and behind the electroplating module magnetic rollers ( 9 ), which bear against the top of the inserted substrate strip. Plant according to claim 8, characterized in that the transport unit arranged in front of and behind the electroplating module, Convex sliding bearing comprises, which on the underside of the inserted substrate strip abutment, wherein the sliding bearings are made of a porous material, through the compressed air is conductive, such that when inserted substrate strip between the sliding bearing and the continuous substrate belt Air cushion trains. Plant according to one of the preceding claims, characterized characterized in that the plate has bores as an air guiding element, the diagonally through the plate is lost. Plant according to one of the preceding claims, characterized characterized in that the anode consists of at least one middle and two edge strips is formed, which are electrically isolated from each other and to which various electrical potentials are connected can.