Title of Invention

"METHOD OF MANUFACTURING A DATA CARRIER"

Abstract

There is described a data carrier for storing binary data, for example a telephone card, and a method of manufacturing this data carrier. Known storage media with an irreversible storage mechanism contain superficially applied patterns, comprising metal layers, the first layer abutting on the carrier material consisting of a nickel/phosphorous alloy and the second of a tin/lead alloy layer. In contrast, the data carriers according to the invention contain as a second metal layer a tin/zinc alloy layer. This is less toxic than the known tin/lead alloy layers and is outstandingly suitable for the indicated purpose on the storage media. The manufacturing method for the storage media comprises substantially the following process steps: a) formation of a resist layer with channels on the carrier, in which the surface areas of the carrier corresponding to the metal structures to be formed later, are not covered; b) electroless deposition of a layer of nickel or of a nickel alloy in the channels; c) electrolytic deposition of a tin/zinc alloy layer on the first layer, the exposed surfaces of the carrier being activated by means of an appropriate catalyst for subsequent electroless metal deposition before process step a) or between process step a) and b).

Full Text

The present invention relates to a method of manufacturing' a data carrier. The present invention relates to data carriers for storing binary data by irreversible alteration of structures from metal layers superficially applied to a flat, electrically non-conductive carrier, and to a method of manufacturing these data carriers. Cheque cards are used to an increasing degree for cashless payment at automatic machines. For example, such cards are used for telephoning at public telephone kiosks. Likewise, these cards are used in cashless exchange in any retail premises. These cards also serve for digital data acquisition for example when visiting doctors. As a rule, the data on these data carriers, for example the cash credit stored by payment into an account, are recorded by means of a magnetic strip or, in more complex card systems, on a semiconductor memory integrated into the card. These systems however have various disadvantages. Particularly when only one amount is recorded by payment of a specific cash credit, and respectively only one specific amount is again subtracted from the stored credit, and the new amount is to be stored, the said storage media represent uneconomic systems which are susceptible to interference. In particular cards provided with magnetic strips are insufficiently protected against misuse, as the stored credit can be altered relatively easily. Therefore new storage methods have been sought. In Patent Application BR-A-910 55 85 there is disclosed a method of manufacturing payment cards for public telephones, in which there is applied to an impermeable, non-porous substrate a whole-surface first conductive layer with a higher resistance. applied by chemical methods, preferably a nickel layer with a maximum thickness of 0.3 urn, and thereafter a whole-surface electrolytically deposited metal or alloy layer with a clearly lower resistance and melting point than the first layer, preferably a tin/lead layer, with a thickness of 2 to 15 µm, preferably 2 to 8 µm. During electrolytic deposition, low current densities of 0.5 to 2 A/dm2 are to be used. By means of the memory card manufactured according to this method, cash credits are stored in such a way that, during the manufacturing process, a field matrix is generated in the card, which is formed from individual conductive fields electrically connected together, these fields respectively comprising angular or round structures, in which there are located metal-free areas, so that ring currents may be induced around these fields. In order to call up the stored cash credit by means of a reader device, small coils are placed above the individual fields and a measurement is carried out, by induction of a current in the ring structures, of how many of these rings are closed. At one respective point, the metal ring structures are closed only by a narrow web. Upon an alteration, for example reduction of the cash credit, the narrow webs of the fields are successively destroyed by induction of a current, which in this case however is set higher, so that during subsequent read-out it can be ascertained how many undestroyed closed rings still exist. This means of irreversible information storage is considerably less susceptible to interference and more secure from forgery than previous memory cards. In the Brazilian Patent Application cited there is disclosed a method for manufacturing these telephone cards. According to this, the indicated metal layers are firstly formed over the entire surface, and the individual fields are formed by appropriate etching processes with the aid of structured etching masks. This method however is complex and thus uneconomic. In particular, the narrow webs in the rings, which for example are only 100 urn wide, can only be manufactured with difficulty by the etching processes. As these telephone cards are intended to be produced in large batches and at low cost, a large number of these cards is preferably manufactured in one working step on large plastic substrates, so that these narrow webs, due to the unavoidable offsetting during structuring of the metal layers by means of appropriate masks, are placed at the wrong points. There are also frequently problems in adjusting the width of these small webs in any reproducible manner. Therefore it can occur that such a web is already destroyed during read-out of the stored information, if its width falls below a specific threshold and the resistance of these webs thus likewise falls below a minimum threshold value. Therefore, in DE 44 38 799 A1 there is proposed an improved method of manufacturing such storage media/ In this method there is firstly applied over the whole surface of the non-conductive card carrier a catalyst suitable for electroless deposition of metals. Then the interconnected structures are formed on the carrier surface by means of a masking technique. Thereafter, firstly a first thin metal layer is deposited in an electroless manner, and thereafter a second thicker metal layer is deposited in an electrolytic manner. There is in turn proposed as the first metal layer a nickel layer, and as a second metal layer a tin/lead alloy layer. This method operates without etching steps. The method has the disadvantage that the second layer contains lead as a poisonous metal and therefore on the one hand leads to problems in waste water treatment during the electrolytic manufacturing process and in the disposal of waste materials from the manufacturing method. On the other hand, these cards themselves give rise to considerable waste problems, as the telephone cards are frequently carelessly thrown away along with normal waste and, due to their lead content, lead to increased stress on the environment. Therefore the problem underlying the present invention is to produce a data carrier and a method for its manufacture, by means of which considerably less stress on the environment is caused in waste water preparation and in disposal of waste materials. This problem is solved by data carriers for storing binary data according to claim 1, and by a manufacturing method for the data carriers according to claim 5. An advantageous use of the data carriers is given in claim 14. The data carriers according to the invention are characterised in that they comprise a flat, electrically non-conductive carrier with superficially applied structures from metal layers, the shape of the structures of the metal layers corresponding to the data, and a first metal layer, substantially of nickel or of a nickel alloy, and a second metal layer of a tin/zinc alloy. The method of operation of these data carriers corresponds in theory to the method of operation described in BR-A-910 55 85 and DE 44 38 799 A1. The superficially applied metallic structures in the case of the data carrier are formed from fields connected together, the fields substantially comprising a metal area surrounding a free area, in which an electrical current may be induced, and the metal area is closed at at least one point by a web which is so narrow that the induced current is sufficient to melt the tin/zinc layer deposited on the web, and to interrupt the web. For example, the structures can comprise angular or circular rings with the said narrow web, or also flat areas in which there is respectively located a free area, and which respectively taper at one point into a narrow web (see in this respect Example 1 and Figure 1). The individual binary data are stored and read out independently of one another. During manufacture, exclusively metal structures with the same binary value, i.e. "0" or "1" can be formed on a carrier, or metal structures with differing binary values can be formed, in order to produce specific binary number combinations. In contrast to the previous memory cards, the data carriers according to the invention have a considerably lower toxicity of the metal layers applied thereon. These data carriers contain no toxic lead. The tin/zinc alloy deposited instead of the tin/lead alloy layer proves to be much less toxic than the known alloy layers on these cards. In waste water treatment and ensuing disposal of the electrolytic sludges also, less toxic substances have to be treated. Furthermore, tin/zinc alloy layers are outstandingly suitable as a functional layer in the data carriers according to the invention. Due to their relatively low melting point, these alloy layers may be easily melted by low induction currents in order to debit a stored credit unit, so that the narrow webs produced from such alloy layers in the annular structures, which act as inductances, may be easily destroyed on the carrier cards. Due to their low melting point, an extraordinarily low amount of energy is used during debiting the credit units, and the cards are only thermally stressed to a negligible degree, so that the decorative protective paints applied to the outer skin of these cards are not damaged. In addition, the raw materials for manufacturing these alloy layers are extraordinarily inexpensive. A further advantage resides in the fact that soluble anodes can be used for both alloy elements next to one another, or also insoluble anodes. Finally, it is also possible to deposit the alloy layer from acidic baths. Another advantage is that the manufacturing method for the data carriers requires no etching processes. On the other hand, the following electrolytically depositable alloy systems have proved unsuitable, for example: tin/antimony, tin/bismuth, tin/indium, tin/silver, tin/antimony/silver and tin/copper/silver. These alloys are in fact known as solderable alloys. However they are not suitable for the purpose of application indicated here. Depending on the composition, the melting point of the alloy according to the invention lies between 196°C (eutectic) and about 230°C. Suitable alloy systems according to the invention thus have a zinc content of 0.5 to a maximum 20% by weight and a tin content of 80 to 95.5% by weight. Basically, in addition to tin and zinc, other metals may be contained in the alloy, as long as the alloy has a melting point in the indicated temperature range. The tin/zinc alloy layer is deposited from an aqueous electrolytic metallising bath, which contains respectively one source of tin ions and one of zinc ions, furthermore at least one complex former and a means for adjusting the pH value as well as further ingredients, such for example as grain refiners, antioxidants, brighteners, stabilisers, wetting agents and other materials. The alloy bath is preferably set to a pH value of less than 7, in order where required to avoid damage the resist applied to the carrier materials during the electrolytic deposition process. In accordance with the further bath composition, acids or bases are used for pH adjustment. Salts or esters of gluconic acid or salts of phosphonic acids are used for example as complex formers. The salts, for example alkali salts, of 2-phosphono-1, 2, 4-butane tricarboxylic acid are preferably used as salts of phosphonic acids. Typical bath compositions of a pH value below 7 are assembled in Tables 1 and 2. The most favourable values are given in brackets. Such baths are known for example from J.W. Price, Tin and Tin-Alloy Plating, Electrochemical Publications Limited, Great Britain, 1983. Basically however baths may also be used with a pH value above 7 if resist types are used which are resistant to alkalis, or if a variant method is selected in which the resist is removed from the carrier surfaces before the metal layers are deposited. Such baths are given in Tables 3 to 6. Baths are preferred which are operated at ambient temperature, as the substrate materials are not damaged thereby. Table 1: Gluconate Bath (Table Removed) Table 2: Phosphonate Bath (Table Removed) The alloy can be deposited in a range of current density of up 20 A/dm2, preferably from 1 to 4 A/dm2. Table 3: Potassium Stannate/cyanide Bath (Table Removed) Table 4: Pyrophosphate Bath (Table Removed) There may be used as anodes soluble anodes of a tin/zinc alloy with the composition, which is also deposited, or insoluble anodes, for example of stainless steel, and also platinised titanium metal mesh or mixed oxide electrodes, particularly with an IrO2 coating. Basically, soluble and insoluble anodes may be used next to one another, for example in order to adjust the ratio of the tin and zinc ions in the deposition bath via the ratio of the current components of both anodes. If necessary the tin and zinc ions require to be supplemented via the corresponding salts. The system for depositing alloys is conventionally equipped with various auxiliary units. For example, these systems contain means for circulating the bath and for filtering the treatment liquid. In order to manufacture the storage means, the procedure is as follows: An acrylnitrile-butadiene-styrol copolymer (ABS) is normally used as a carrier material. In order to be able to manufacture the maximum number of data carriers according to the invention in one working step, two substrates, existing in film form, are glued together back-to-back, their edges being fused together. In this way on the one hand sufficient stability of the substrates in the electrolytic baths is achieved and on the other hand the carrier materials are prevented from being coated on both sides, as only one side of the carrier in each case is intended to carry the circuit pattern. For electrolytic treatment, the welded carrier materials are secured to appropriate frameworks, and successively dipped in a vertical position into the various treatment baths. In order to achieve sufficient adhesive strength of the metallic coatings on the non-conductive substrate, the ABS surfaces are superficially roughened by means of a chromium/sulphuric acid method. For this purpose the substrates may firstly be brought into contact with solutions containing wetting agents or swelling agents. After a rinsing stage, the surfaces are then roughened in a conventional chromium/sulphuric acid solution. For this purpose solutions are used which contain for example 360 g/l chromium trioxide and 360 g/l concentrated sulphuric acid. However, chromium/sulphuric acid solutions with other concentrations may also be used. Following this stage the ABS sandwiches are again rinsed and thereafter treated with a solution to remove chromium-(VI) ions, for example a sodium hydrogen sulphite solution. After further rinsing of the sandwich with water, its surfaces are then activated. For this purpose an appropriate catalyst must be applied in order to activate the surfaces for electroless metallisation. The normal catalysts are used, for example palladium colloids, stabilised with tin-(ll)-salts, or polymers such for example as polyvinyl alcohol or polyvinyl pyrrolidon. The palladium clusters adsorbed on the substrates, mixed with the protective colloids, are freed of the latter in a second method step (acceleration). Further, so-called ionogenic palladium activators can be used for catalysis, in which palladium complexes with organic complex ligands, for example 2-aminopyridine, are used as a preliminary stage for catalysis. The complexes adsorbed on the carrier materials are reduced to metallic palladium in a second method stage by means of strong reduction agents, for example dimethylamine borane or sodium boron hydride. After a further rinsing step with water, the carrier is then provided with a resist layer containing channels in order to produce the necessary metal structures, and in which those surface areas of the carrier are not covered which correspond to the later metal structures to be formed. Both a photoresist and a non-photosensitive resist may be used as a resist. If a photoresist is used, this, after whole-surface or partial application to the carrier surfaces, must be illuminated with the circuit pattern of the metal structures and subsequently developed. In this way channels are formed in the resist layer. If on the other hand a non-photosensitive resist is used, the circuit pattern is already produced during printing of the resist onto the carrier surfaces, i.e. generally by screen printing. Particularly suitable are positively-operating resists, in which the illuminated points are rendered soluble, so that these resist portions are removed during the subsequent development process. The channels are then formed at this point. However, negatively-operating resists may also be used. Basically, photoresist films may be used. For reasons of cost it is however preferred to apply the resists to the carriers in a liquid form. In the latter case the resists may be applied over the whole surface in a curtain coating method, in a roller-coater method or with smaller substrates by spin coating or by means of the screen printing technique. In the latter case a liquid photoresist, in the case of a multiple copy, may for example firstly be printed only on the surfaces corresponding to a circuit pattern, without the individual structure elements being produced therefrom. The circuit structure can then be formed in a second working step in an illumination/development process. In this way the finest structural elements can be imaged and simultaneously, unusable surfaces between the individual circuits on the multiple copy can be left alone by the screen printing. A further variant method consists in printing a photoresist by screen printing on the carrier surfaces in such a way that the circuit patterns arise during printing, and the narrow webs are only formed by a subsequent illumination/development process. Then the nickel or nickel alloy layer is deposited in an electroless manner in the channels, preferably at a pH value below 7. A nickel/phosphorous alloy is preferably used for this metal coating. There is used, as a particularly suitable bath, a nickel electrolyte which contains a hypophosphite salt as a reduction agent for the nickel ions. Commercially available baths are used for this purpose. Alternatively, a nickel or nickel/boron layer can be deposited. In the latter case for example dimethylamine borane is used as a reduction agent. In order to produce the data carriers according to the invention, the nickel, nickel/boron or nickel/phosphorus layer is deposited at a thickness of preferably 0.3 urn. After the surfaces have again been rinsed with water, the tinc/zinc alloy layer described above is applied to the nickel layer electrolytically at a thickness of about 8 urn. The resist, after production of the metallic structures, can be removed from the zinc/zinc alloy layer and the metal applied in an electroless manner (Stripping process). Thereafter the carrier is covered by a decorative paint layer. In a further preferred variant method, the catalyst required for electroless metallisation is applied only after formation of the circuit pattern by the resist layer. In this case the exposed surfaces of the carrier and of the resist layers are activated after formation of the resist layer with the channels and before the electroless metallisation. The resist in this variant embodiment is again removed from the carrier before the electroless metallisation. This type of method offers the advantage that the manufacturing process need not be interrupted several times, as the method steps for activating the surfaces with the catalyst and for forming the metal layers are preferably normally carried out in an electrolytic system without interruption, whilst the masks in other systems are produced for example by means of screen printing or using photoresists. In the variant method described above, the manufacturing process must be interrupted twice, i.e. once after activation, the carrier materials requiring to be transferred, for further processing for producing the mask, into another system, and once after setting the mask, in order to generate the metal layers in the electrolytic system. Such a procedure is uneconomic, as for logistic reasons the manufacturing process lasts considerably longer and because the interruptions also lead to faults, for example due to the fact that oxide layers or other disturbing layers form on the catalyst layer, which reduce or cancel its activity. Therefore the second variant method is the preferred embodiment. In this case the carrier materials can firstly be processed in the system for producing the mask. They are only then transferred into the electrolytic system. In this way a rapid working sequence is ensured, and faults occur to a reduced degree. If operation is carried out in accordance with the procedure indicated above, it is particularly favourable to remove the resist mask from the carrier material again before the formation of the metal layer. This affords many procedural possibilities, as frequently the preferred resist materials are not chemically stable relative to the metallising baths. By means of the procedure selected, the resist materials may now be selected independently of the metallising baths, without the necessity for precise co-ordination as regards tolerance to chemicals of the resist materials relative to the metallising baths. Therefore in this case the alkaline deposition baths named before for the tin/zinc alloy may also be used in this case. Treatment of the substrates may be undertaken in a previously known dipping system, these being successively dipped into the containers with the corresponding treatment liquids. Another preferred procedure consists in passing the substrates in a horizontal or vertical alignment in a horizontal direction of transport through a system suitable for this, and treating them by means of appropriate devices for bringing the treatment liquids in this system into contact, for example by means of splash nozzles. According to the present invention there is provided a method of manufacturing a data carrier comprising the following essential process steps: a) formation of a resist layer with channels on the carrier, in which the surface areas of the carrier corresponding to the metal structures to be formed later; are not covered; b) electroless deposition of a layer of nickel or of a nickel alloy in the channels: c) electrolytic deposition of a tin/zinc alloy layer on the first layer. the exposed surfaces of the carrier being activated by means of an appropriate catalyst for sybsequent electroless metal deposition before process step a) or between process step a) and b). Embodiments given by way of example are indicated in the following in order to explain the invention in more detail. According to the examples, circuit patterns are produced on the carrier materials in accordance with the schematic illustration in Figure 1. In this Figure, the dark areas represent the metallic layers and the light areas the carrier surface not coated with metal. The reference number 1 indicates a ring-shaped field in which, by means of a coil located above the field, a ring-shaped current can be induced. The reference number 2 indicates a narrow web which can be melted through by induction of an amplified current, so that the ring is broken. By means of this interruption, a data unit is irreversibly stored in the circuit: upon renewed read-out by means of the coils located above the fields, no further current is induced in the now interrupted ring. Example 1: Two ABS foils 40 cm x 60 cm large were welded back-to-back in such a way that only their edges were fused together. The resultant sandwich was then printed with the photosensitive screen printing pigment Imagecure ® AQ of the Company ASI, Phoenix, USA in such a way that fields lying next to one another 50 mm x 80 mm large, which were of the size of the circuit patterns to be produced, are covered by the pigment. Then the circuit patterns were illuminated through a mask with the conductor pattern, onto the individual card fields, and then developed in a suitable developing agent, for example a diluted sodium carbonate solution. Thereafter the ABS sandwiches were dipped in an aqueous cleaning solution containing wetting agent. After rinsing with water the ABS surfaces not covered by the resist were roughened by means of a chromium/sulphuric acid solution containing 360 g/l chromium trioxide and 360 g/l concentrated sulphuric acid, at 60°C during a treatment time of 5 minutes. In this way also the resist surfaces were slightly roughened. After rinsing the substrates, these were dipped in an aqueous solution containing 10 g/l sodium hydrogen sulphite, in order to remove adhering residues of chromium-(VI) ions. After further rinsing, the sandwiches were treated in a pre-dipping solution containing 10 ml/I concentrated sulphuric acid for 3.5 minutes. Thereafter the sandwiches were directly dipped into the catalyst solution without a further rinsing stage. Said solution contained a complex of palladium sulphate and 2-aminopyridine; the concentration, calculated according to Pd2+, came to 200 mg/l. After activation, the sandwiches were again rinsed and thereafter treated for 3.5 minutes in a reduction solution containing 1 g/l sodium boron hydride. There were then formed on the ABS surfaces metallic, catalytically effective palladium clusters. Then the resist was entirely removed in a concentrated aqueous sodium or potassium hydroxide solution. For this purpose the substrates were brought into contact with this solution for about 2 minutes. Thereafter, the metal coatings were built up. For this purpose the rinsed ABS sandwiches were coated in an electroless nickel bath with sodium hypophosphite as a reduction agent. The nickel bath Noviganth Ni AK ® of the Firm Atotech Deutschland GmbH, Berlin, DE, set to a pH value of 6.5 to 6.9, was used. The nickel/phosphorus layer was deposited at a working temperature of 45°C. In order to be able to deposit a layer about 0.3 urn thick, the substrates were left in the bath for 7 minutes. After renewed rinsing of the plates, these were dipped into the tin/zinc bath whose composition is given in Table 1 (values in brackets). Operation was with a cathodic current density of 2 A/dm2. Tin/zinc plates were used as soluble anodes, containing a composition of about 67% by weight of tin and 37% by weight of zinc. The bath was operated at ambient temperature. Deposition was carried out until a layer about 8 urn thick had been deposited. An alloy layer was obtained with a composition of 67% by weight tin and 37% by weight zinc. After metal deposition the plates were rinsed, dried and then covered with decorative protective paint. Thereafter the individual cards were separated from the multiple copy by cutting. Example 2: The process sequence of Example 1 was substantially repeated. In contrast to the sequence in Example 1, however, the resist layer was applied only after the activation step, including the subsequent reduction, and structured by illumination and developing. The resist was left on the substrate after deposition of the tin/zinc alloy layer. Furthermore, instead of the gluconate bath indicated in Table 1, the bath indicated in Table 2 was used for depositing the tin/zinc alloy (concentration values in brackets). The cathodic current density was again 2 A/dm2. Soluble tin/zinc anodes (pellets) in titanium baskets were used as anodes, which had a composition of 84% by weight tin and 16% by weight zinc. The treatment was carried out at ambient temperature. After deposition of the tin/zinc layer with a thickness of 8 urn, its composition was determined. The alloy contained the same quantities of tin and zinc as the anodes used. Example 3: Example 1 was repeated. Instead of the gluconate bath however the stannate/complex bath II given in Table 6 was used (concentration values in brackets). The operating temperature of the bath was 65°C and the cathodic current density 2 A/dm2. Insoluble anodes in the form of platinised titanium metal mesh were used. The bath ingredients being consumed had therefore to be supplemented by the addition of salts. After deposition of an alloy layer about 8pm thick, its composition was determined. According to this the alloy contained about 80% by weight tin and about 20% by weight zinc. Example 4: Example 3 was repeated. However, the ABS sandwiches were treated in a horizontal system, in which the ABS plates were continuously transported in a horizontal position and direction, and were brought into contact with the individual treatment liquids. In this system on the one hand there were disposed squeezing rollers, between which respective spaces were provided above the plates, in which the treatment liquids could be built up to form a liquid bath, and splash nozzles, which were attached beneath the transport plane and ensured the feed of liquid, so that the plates were transported through the treatment bath, and on the other hand spray nozzles which were located above and beneath the transport plane. All disclosed features and combinations of disclosed features are the subject-matter of this invention, where they have not expressly been referred to as known. We Claim :- 1. Method of manufacturing a data carrier comprising the following essential process steps: a) formation of a resist layer with channels on the carrier, in which the surface areas of the carrier corresponding to the metal structures to be formed later; are not covered; b) electroless deposition of a layer of nickel or of a nickel alloy in the channels: c) electrolytic deposition of a tin/zinc alloy layer on the first layer. the exposed surfaces of the carrier being activated by means of an catalyst of the kind as discribed for subsequent electroless metal deposition before process step a) or between process step a) and b). 2. Method as claimed in one of claims 1 and 2, wherein the exposed surfaces of the carrier are activated between process step a) and process step b), and the resist is removed again from the carrier before process step b) is carried out. 3. Method as claimed in one of claims 1 and 2, wherein the tin/zinc alloy layer is deposited from an aqueous electrolytic metallising bath containing respectively at least one source of tin ions and one of zinc ions, at least one complex former and a means of adjusting the pH value. 4. Method as claimed in claim 3, wherein the bath is set to a pH value beneath 7. 5. Method as claimed in one of claims 3 and 4, wherein salts or esters of gluconic acid are used as complex formers. 6. Method as claimed in one of claims 3 and 4, wherein salts of phosphonic acids are used as complex formers. 7. Method as claimed in claim 6, wherein the salts of 2-phosphone-l, 2, 4-butane tricarboxylic acid are used as salts of phosphonic acids. 8. Method as claimed in one of the preceding claims, wherein a nickel/phosphorus layer is deposited as a first metal layer. 9. Method as claimed in one of claims 1 to 8, wherein the resist is applied only to the surface areas of the carrier which are later not covered by the metal structures. 10. Method of manufacturing a data carrier substantially as herein described with reference to the accompanying drawings.

Documents:

2689-del-1997-abstract.pdf

2689-del-1997-assignment.pdf

2689-del-1997-claims.pdf

2689-del-1997-correspondence-others.pdf

2689-del-1997-correspondence-po.pdf

2689-del-1997-description (complete).pdf

2689-del-1997-form-1.pdf

2689-del-1997-form-13.pdf

2689-del-1997-form-19.pdf

2689-del-1997-form-2.pdf

2689-del-1997-form-3.pdf

2689-del-1997-form-6.pdf

2689-del-1997-gpa.pdf

2689-del-1997-pct-409.pdf

2689-del-1997-petition-137.pdf

2689-del-1997-petition-138.pdf