JP5440410B2 - Method and apparatus for producing metallized resin film - Google Patents

Description

  The present invention relates to a method for producing a metallized resin film and a production apparatus therefor, and more specifically, rolls a long resin film with a primary metal layer in which a primary metal layer is formed on the surface of the long resin film without using an adhesive. The present invention relates to a method and an apparatus for producing a metallized resin film in which a secondary metal layer is formed by electroplating on a primary metal layer while being conveyed by two rolls.

  A metallized resin film typified by a metallized polyimide film is a film in which a metal layer is formed on at least one surface of a resin film such as polyimide. In recent years, a driving semiconductor for displaying an image on a liquid crystal screen has been used. It is widely used for applications such as semiconductor mounting substrates to be mounted. In particular, a polyimide film as a base material for a metallized polyimide film has excellent heat resistance, and is inferior to other plastic materials in mechanical, electrical and chemical characteristics.

  Therefore, the metallized polyimide film is used as an insulating substrate material for electronic parts such as a printed wiring board (PWB), a flexible printed wiring board (FPC), a tape for automatic tape bonding (TAB), and a chip-on film (COF). It is used a lot. Such PWB, FPC, TAB, and COF are obtained by wiring patterning using a metallized polyimide film in which a metal layer is coated on at least one surface of a polyimide film.

  Of these, COF using a metallized polyimide film has attracted attention as a method for mounting a driver IC chip for displaying a liquid crystal screen. The COF can be mounted with a fine pitch as compared with TCP (Tape Carrier Package), which is a conventional mounting method, and is an easy mounting method for reducing the size and cost of the driver IC. As a manufacturing method of this COF, a metallized polyimide film in which a copper layer is provided on a polyimide film is generally used, fine patterning is performed by a so-called subtractive method, and tin plating and a solder resist are coated on a desired portion. The method is common.

  Incidentally, in the patterning of the copper layer by the subtractive method, first, a resist layer is provided on the surface of the copper layer, a mask having a predetermined wiring pattern is provided on the resist layer, and exposure is performed by irradiating ultraviolet rays from above. Development is performed to obtain an etching mask for etching the copper layer. Next, the exposed metal portion is removed by etching, and the remaining resist layer is removed to obtain a wiring pattern.

  The metallized polyimide film has a three-layer metallized polyimide film in which a metal foil and a polyimide film are bonded using an adhesive, and a two-layer metallization in which a metal layer is formed directly on the surface of the polyimide film without using an adhesive. There is a polyimide film. In recent years, there is a demand for a substrate that can draw fine wiring, and because it is not affected by the adhesive layer and a material that uses the inherent stability of polyimide can be obtained, it is a two-layer metallized polyimide film without an adhesive layer. The demand is growing.

  In the case of producing a two-layer metallized polyimide film, there is a so-called metalizing method as a method for forming a metal layer on the polyimide film surface. In the metalizing method, for example, a base metal thin film made of a nickel alloy such as a nickel chromium alloy is formed by a dry plating method such as a sputtering method, and a copper thin film is formed thereon to give good conductivity, thereby forming a primary metal. Layer. Since this primary metal layer alone is thin as a metal conductor, in order to increase the thickness of the metal conductor, copper is formed on the primary metal layer by a wet plating method such as electroplating to form a secondary metal layer. doing.

  Here, in manufacturing the above-mentioned two-layer metallized polyimide film, to form a secondary metal layer on the surface of the primary metal layer by electroplating, a long resin film with a primary metal layer is conveyed by roll-to-roll. However, the anode may be immersed in a plating tank filled with a plating solution and electroplated with the anode. For example, Patent Document 1 discloses that a polyimide film in which a metal film is formed in a sputtering process is transported into a plating tank provided with a plurality of anodes and filled with an electrolytic solution, and the amount of current supplied to the anode is sequentially increased as it proceeds through the plating tank. A continuous plating method is described in which a uniform and good electroplating film is continuously formed by increasing the number.

  On the other hand, in patent document 2, after carrying out copper electroplating by carrying out roll-to-roll similarly to the said patent document 1, after winding up or before winding up the obtained copper laminated type flexible printed circuit board material A technique for improving the fold resistance index by performing a heat treatment on is disclosed. However, the method of Patent Document 2 is a technique for suppressing the occurrence of disconnection and cracks during bending, and no countermeasure is taken against the occurrence of wrinkles.

JP 2009-026990 A JP 2007-262493 A

  In the production of the above-described two-layer metallized polyimide film, a long resin film with a primary metal layer was transported by roll-to-roll, and obtained after forming a secondary metal layer by electroplating on the surface of the primary metal layer. Although a long metallized polyimide film is wound around a winding roll, there is a problem that wrinkles are locally generated in the metallized polyimide film during winding. In the present situation where a metallized polyimide film is required as a base material on which fine wiring can be drawn, since the generation of wrinkles affects wiring patterning processing, improvement has been demanded.

  The present invention has been made in view of such conventional problems, and is obtained by forming a secondary metal layer by electroplating while transporting a long resin film with a primary metal layer by roll-to-roll. An object of the present invention is to provide a method for producing a metallized resin film that can eliminate the occurrence of wrinkles when winding a long metallized resin film, and a production apparatus therefor.

  As a result of repeated studies to produce a wrinkled metallized resin film, the present inventor has found that a tension is applied to the metallized resin film after the secondary metal layer is formed on the primary metal layer by electroplating. It has been confirmed that a metallized resin film can be obtained by performing a heat treatment while adding, so that local distortion can be eliminated, and thus wrinkles do not occur even when wound up, and the present invention has been achieved.

That is, the manufacturing method of the metallized resin film provided by the present invention is a resin film with a primary metal layer having a primary metal layer in which a base metal thin film and a copper thin film are laminated without using an adhesive on one surface of a long resin film. The copper secondary metal layer is formed by electroplating on the surface of the primary metal layer while being unwound from the unwinding roll and transported by roll-to-roll, and the resulting long metallized resin film has a unit cross-sectional area. After applying heat treatment at a temperature of 100 to 150 ° C. while applying a tension of 2.4 to 4.9 N / mm ² per roll, it is wound on a winding roll so that the secondary metal layer faces up .

  Moreover, the apparatus for producing a metallized resin film according to the present invention comprises a resin film with a primary metal layer having a primary metal layer in which a base metal thin film and a copper thin film are laminated without using an adhesive on one surface of a long resin film. Electroplating to form a secondary metal layer of copper by electroplating on the surface of the primary metal layer by repeatedly dipping and unloading in the plating solution in the electroplating tank while unwinding from the winding roll and transporting by roll-to-roll An apparatus, a tension load unit that is installed on the transport path and behind the electroplating apparatus and applies tension to the long metallized resin film obtained by the electroplating apparatus, and a heating unit that heats the metallized resin film And a winding roll for winding the metallized resin film heat-treated by the heat treatment apparatus so that the secondary metal layer faces up.

  According to the present invention, even if the metallized resin film obtained by electroplating while being conveyed by roll-to-roll is wound up in a roll shape, the generation of wrinkles in the wound metallized resin film can be eliminated. And if it heat-processes continuously after electroplating, a metallized resin film without a wrinkle can be manufactured efficiently. Therefore, the metallized resin film according to the present invention is extremely useful as an insulating substrate material for electronic components such as printed wiring boards and chip-on-film (COF) suitable for fine wiring.

It is a schematic side view which shows the manufacturing apparatus of the metallized resin film by the roll-to-roll system of this invention.

  In the first step of the method of the present invention, in the electroplating apparatus, copper is applied to the surface of the primary metal layer by electroplating while the long resin film with the primary metal layer is unwound from the unwinding roll and conveyed by roll-to-roll. The secondary metal layer is formed. The resin film with a primary metal layer used in that case is obtained by forming a primary metal layer in which a base metal thin film and a copper thin film are laminated on one surface of a long resin film without using an adhesive. In addition, as a method for forming the primary metal layer on the surface of the resin film without using an adhesive, a dry plating method such as a vapor deposition method or a sputtering method, or an electroless plating method can be used.

  The primary metal layer includes a base metal thin film made of a metal such as nickel (Ni) or chromium (Cr) or an alloy thereof, and a copper thin film laminated on the base metal thin film. The reason why the copper thin film is provided on the underlying metal thin film is that when the copper layer is directly provided on the underlying metal thin film by electroplating, the current density of electroplating becomes unstable because of high conduction resistance. Therefore, by laminating a copper thin film on the base metal thin film, it is possible to reduce the current resistance and stabilize the current density when forming the copper layer by electroplating.

  The thickness of the base metal thin film is preferably 3 to 50 nm. When the film thickness is less than 3 nm, the etching solution erodes the underlying metal thin film and penetrates into the polyimide film when the metal layer of the obtained metallized resin film is etched to form the wiring, and the wiring floats. This is not preferable because it may occur. On the other hand, if the film thickness exceeds 50 nm, the metal layer may not be completely removed when the wiring is formed by etching, and the remaining residue may cause insulation failure between the wirings.

  Moreover, it is preferable that the film thickness of the copper thin film laminated | stacked on a base metal thin film shall be 10 nm-1 micrometer, and the range of 20 nm-0.8 micrometer is still more preferable. The reason is that if the thickness of the copper thin film is less than 10 nm, the energization resistance in the electroplating for forming the copper layer cannot be lowered sufficiently, and conversely if the thickness exceeds 1 μm, it takes time to form the copper thin film. This is because it takes too much and deteriorates productivity and impairs economic efficiency.

  Examples of the resin film include a polyimide film, a polyamide film, a polyester film, a polytetrafluoroethylene film, a polyphenylene sulfide film, a polyethylene naphthalate film, and a resin film selected from a liquid crystal polymer film. It is desirable in that it is suitable for applications requiring connection at a high temperature such as solder reflow, and a polyimide film is particularly preferable. A resin film having a thickness of 8 to 75 μm can be preferably used. Incidentally, an inorganic material such as glass fiber can be appropriately added to the resin film.

  Next, a first step of forming a secondary metal layer on the surface of the primary metal layer using an electroplating apparatus with an electroplating apparatus while conveying the above-described long resin film with a primary metal layer by roll-to-roll. Will be described in detail with reference to FIG. The metallized resin film manufacturing apparatus shown in FIG. 1 is based on a roll-to-roll method, and is composed of an electroplating apparatus A and a heat treatment apparatus B.

  In the electroplating apparatus A, the long resin film F with a primary metal layer is unwound from the unwinding roll 1, sent to the plating tank 2 through the power supply roll 3a, and immersed in the plating solution 2a. The resin film F with the primary metal layer that has entered the plating tank 2 is carried out of the plating tank 2 through the reverse roll 4a. As described above, the resin film F with the primary metal layer is repeatedly immersed in the plating solution 2a a plurality of times (four times in FIG. 1), and in the meantime, an electroplating circuit (plating) composed of each feeding roll and a pair of anodes. The cell) forms copper as a secondary metal layer on the surface of the primary metal layer. The thickness of the secondary metal layer is generally several μm to several tens of μm.

  Specifically, the power supply roll 3a and the pair of anodes 5a and 5a constitute an electroplating circuit (plating cell). Similarly, the power supply roll 3b and the anodes 5b and 5b, the power supply roll 3c and the anodes 5c and 5c, The power feeding roll 3d and the anodes 5d and 5d constitute an electroplating circuit. Note that a known oxygen-free phosphorous copper or insoluble anode can be used as the anode, and a copper plating solution corresponding to the anode may be used as the plating solution.

  Each of the power supply rolls 3a, 3b, 3c, and 3d is connected to an individual power supply device (not shown), and contacts the primary metal layer of the resin film F with the primary metal layer to supply electric power necessary for electroplating. . The energization amount supplied to each of the power supply rolls 3a, 3b, 3c, 3d and each of the anodes 5a, 5a, 5b, 5b, 5c, 5c, 5d, 5d is along the path along which the resin film F with the primary metal layer is conveyed. Thus, a uniform and good copper secondary metal layer can be formed. In addition, the conveyance speed of the resin film F with a primary metal layer and the current density of each electroplating circuit (plating cell) can be suitably determined according to the thickness of the secondary metal layer.

  In the copper secondary metal layer thus formed, stress is generated during the electroplating process. That is, due to the expansion and contraction due to moisture absorption of the resin film that is repeatedly immersed in the plating solution, thermal expansion and contraction due to Joule heat due to electric power supplied by electroplating, bending due to conveyance of a long resin film, etc., the secondary metal layer Stress is generated. Since this stress is not uniform in the long metallized resin film, it becomes a local strain and accumulates in the secondary metal layer.

  As a result, when the metallized resin film obtained by electroplating in a roll-to-roll system is wound on a winding roller, the metallized resin film is caused by the distortion accumulated locally in the secondary metal layer. In some cases, band-like wrinkles may occur in the longitudinal direction. This band-like wrinkle is called a gauge band and becomes a serious defect for the quality of the metallized resin film.

  In the method of the present invention, in the second step, the long metallized resin film obtained in the first step is subjected to a heat treatment by a heat treatment apparatus having a tension load means and a heating means tension, thereby locally. The distortion of the stress accumulated in the film is removed to prevent the generation of wrinkles. By heat-treating the metallized resin film while applying tension, the local stress accumulated in the metallized resin film in the first step is relieved and distortion is eliminated, so that the generation of wrinkles is suppressed. it is conceivable that.

  The heat treatment of the long metallized resin film in the second step will be specifically described with reference to FIG. Before the metallized resin film S obtained by forming a copper secondary metal layer on the long resin film F with a primary metal layer in the first step is wound up by the take-up roll 7, the guide roll 6 Is transferred to the heat treatment apparatus B. In the heat treatment apparatus B, the metallized resin film S is heated to a predetermined temperature by the heating units 9a and 9b while applying a constant tension to the metallized resin film S by a tension load unit such as a pair of tension rolls 8a and 8b. .

  An annealing furnace or the like can be used as the heat treatment apparatus B, and various heaters or the like can be used as the heating means 9a and 9b. Among them, a far infrared heater is particularly preferable. Moreover, it is preferable to arrange | position heating means 9a, 9b, such as a far-infrared heater, so that the surface (back surface) in which the secondary metal layer of the metallized resin film S is not formed may be opposed. Thus, if it heats by the far infrared rays from the back surface side of the metallized resin film S, a resin film will be heated by a far infrared rays and a secondary metal layer can be heated indirectly with the heat from the resin film.

The tension applied to the metallized resin film during the heat treatment is in the range of 2.4 to 4.9 N / mm ² per unit cross-sectional area of the metallized resin film. When the tension is less than 2.4 N / mm ² , the stress is not relieved, so that the removal of strain becomes insufficient, and a metallized resin film without wrinkles cannot be obtained. On the other hand, if the tension exceeds 4.9 N / mm ² , the metallized resin film is excessively stressed and the strain cannot be removed.

  The heat treatment temperature of the metallized resin film to which tension is applied is in the range of 100 to 150 ° C. When the heat treatment temperature is less than 100 ° C., the stress of the long metallized resin film cannot be sufficiently relaxed, and a metallized resin film without wrinkles cannot be obtained. On the other hand, if the heat treatment temperature exceeds 150 ° C., the stress is increased, so that the effect of suppressing wrinkles cannot be obtained. In addition, although the heat processing time can be selected suitably, about 40 to 60 second is desirable. A long heat treatment time is not preferable because the productivity of the metallized resin film is lowered.

  The electroplating in the first step and the heat treatment in the second step are performed continuously, that is, on a long resin film with a primary metal layer (metalized resin film after electroplating) conveyed by roll-to-roll. It is preferable to arrange an electroplating apparatus and a heat treatment apparatus on the conveyance path, and continuously process the resin film without stopping the conveyance. However, it is also possible to dispose the electroplating apparatus and the heat treatment apparatus on different transport paths, wind up the electroplated metallized resin film, and then unwind it again to perform the heat treatment.

  When the electroplating in the first step and the heat treatment in the second step are performed continuously, the tension during electroplating and the tension during the heat treatment do not have to be the same. The tension at the time of electroplating is appropriately selected according to the conditions of electroplating, but the tension at the time of heat treatment is determined by placing a known nip roll (not shown) between the electroplating apparatus and the heat treatment apparatus. Can be controlled within a predetermined range.

  In the metallized resin film S that has been heat-treated in the second step, as shown in FIG. 1, the secondary metal layer of copper is face up (that is, the secondary metal layer does not face the winding roll 7 side). As shown in FIG. Therefore, the metallized resin film S wound up in a roll shape has a copper secondary metal layer on the surface side of the roll. When the copper secondary metal layer is wound upside down, even when the heat treatment is performed, strip-like wrinkles (that is, gauge bands) are often generated in the longitudinal direction. However, the secondary metal layer is face up. By winding up, the generation of wrinkles can be suppressed.

  Using a roll-to-roll type metallized resin film manufacturing apparatus equipped with an electroplating apparatus A and a heat treatment apparatus B shown in FIG. 1, continuous electroplating of copper and heat treatment are performed on a long polyimide film with a primary metal layer. To obtain a metallized polyimide film.

  That is, the polyimide film used was Kapton (registered trademark) manufactured by Toray DuPont Co., Ltd. with a width of 50 cm, and a 20 wt% chromium-nickel alloy thin film having a thickness of 100 nm and a copper thin film having a thickness of 1000 nm were formed on one surface by sputtering. A polyimide film with a primary metal layer was formed.

  On the surface of the primary metal layer of the obtained polyimide film with a primary metal layer, electroplating was performed with an electroplating apparatus A to form a copper secondary metal layer having a thickness of 8 μm to obtain a metallized polyimide film. A copper sulfate solution having a pH of 1 or less was used as the plating solution, and a titanium anode coated with iridium oxide was used as the anode.

[Examples 1 to 4]
In Example 1, the metallized polyimide film was continuously conveyed from the electroplating apparatus A to the heat treatment apparatus B, and heated to 100 ° C. with a far infrared heater while applying a tension of 2.4 N / mm ^2. A heat treatment time of 52 seconds) was applied. The metallized polyimide film after the heat treatment was continuously wound around a winding roll in a roll shape so that the secondary metal layer of copper was face up.

In Example 2, the metallized polyimide film was heat-treated in the same manner as in Example 1 except that it was heated to 150 ° C. while applying a tension of 2.4 N / mm ² (heat treatment time: 52 seconds). It wound up on the winding roll so that a metal layer might face up.

In Example 3, the metallized polyimide film was heat treated in the same manner as in Example 1 except that it was heated to 100 ° C. while applying a tension of 4.9 N / mm ² (heat treatment time: 52 seconds). It wound up on the winding roll so that a metal layer might face up.

In Example 4, the metallized polyimide film was heat-treated in the same manner as in Example 1 except that it was heated to 150 ° C. while applying a tension of 4.9 N / mm ² (heat treatment time: 52 seconds). It wound up on the winding roll so that a metal layer might face up.

  As for each metallized polyimide film wound up by performing each heat treatment in Examples 1 to 4 above, no occurrence of wrinkles was confirmed in visual appearance inspection, and good results were obtained. These results are summarized in Table 1 below, where “O” indicates that no occurrence of wrinkles was confirmed.

[Comparative Examples 1 to 12]
In Comparative Example 1, the metallized polyimide film was heat treated in the same manner as in Example 1 except that it was heated to 90 ° C. while applying a tension of 2.0 N / mm ² (heat treatment time: 52 seconds). It wound up on the winding roll so that a metal layer might face up.

In Comparative Example 2, the metallized polyimide film was heat-treated in the same manner as in Example 1 except that it was heated to 100 ° C. while applying a tension of 2.0 N / mm ² (heat treatment time: 52 seconds). It wound up on the winding roll so that a metal layer might face up.

In Comparative Example 3, the metallized polyimide film was heat-treated (heat treatment time: 52 seconds) in the same manner as in Example 1 except that the metallized polyimide film was heated to 150 ° C. while applying a tension of 2.0 N / mm ^2. It wound up on the winding roll so that a metal layer might face up.

In Comparative Example 4, the metallized polyimide film was heat-treated (heat treatment time: 52 seconds) in the same manner as in Example 1 except that the metallized polyimide film was heated to 160 ° C. while applying a tension of 2.0 N / mm ^2. It wound up on the winding roll so that a metal layer might face up.

In Comparative Example 5, the metallized polyimide film was heat treated in the same manner as in Example 1 except that it was heated to 90 ° C. while applying a tension of 2.4 N / mm ² (heat treatment time: 52 seconds). It wound up on the winding roll so that a metal layer might face up.

In Comparative Example 6, the metallized polyimide film was heat treated in the same manner as in Example 1 except that it was heated to 90 ° C. while applying a tension of 4.9 N / mm ² (heat treatment time: 52 seconds). It wound up on the winding roll so that a metal layer might face up.

In Comparative Example 7, the metallized polyimide film was heat treated in the same manner as in Example 1 except that it was heated to 90 ° C. while applying a tension of 5.3 N / mm ² (heat treatment time: 52 seconds). It wound up on the winding roll so that a metal layer might face up.

In Comparative Example 8, the metallized polyimide film was heat-treated (heat treatment time: 52 seconds) in the same manner as in Example 1 except that it was heated to 100 ° C. while applying a tension of 5.3 N / mm ^2. It wound up on the winding roll so that a metal layer might face up.

In Comparative Example 9, the metallized polyimide film was heat treated in the same manner as in Example 1 except that it was heated to 150 ° C. while applying a tension of 5.3 N / mm ² (heat treatment time: 52 seconds). It wound up on the winding roll so that a metal layer might face up.

In Comparative Example 10, the metallized polyimide film was heat-treated (heat treatment time: 52 seconds) in the same manner as in Example 1 except that it was heated to 160 ° C. while applying a tension of 5.3 N / mm ^2. It wound up on the winding roll so that a metal layer might face up.

In Comparative Example 11, the metallized polyimide film was heat-treated (heat treatment time: 52 seconds) in the same manner as in Example 1 except that it was heated to 160 ° C. while applying a tension of 2.4 N / mm ² to obtain a secondary copper It wound up on the winding roll so that a metal layer might face up.

In Comparative Example 12, the metallized polyimide film was heat-treated (heat treatment time: 52 seconds) in the same manner as in Example 1 except that the metallized polyimide film was heated to 160 ° C. while applying a tension of 4.9 N / mm ^2. It wound up on the winding roll so that a metal layer might face up.

  As for each metallized polyimide film wound up by performing each heat treatment of Comparative Examples 1 to 12, generation of wrinkles was confirmed in the visual appearance inspection. These results are collectively shown in Table 1 below together with Examples 1 to 4 above, where “x” indicates that the occurrence of wrinkles was confirmed.

[Comparative Example 13]
In Comparative Example 13, the metallized polyimide film was continuously conveyed from the electroplating apparatus A to the heat treatment apparatus B, and heated to 100 ° C. with a far infrared heater while applying a tension of 2.4 N / mm ^2. (Heat treatment time: 52 seconds). The metallized polyimide film after the heat treatment was continuously wound up in a roll shape on a take-up roll so that the copper secondary metal layer faced reversely as in Example 1.

  As for the metallized polyimide film wound around the winding roll so that the copper secondary metal layer faced down, generation of wrinkles was confirmed by visual inspection.

A Electroplating apparatus B Heat treatment apparatus F Resin film with primary metal layer S Metallized resin film 1 Unwinding roll 2 Plating tank 2a Plating solutions 3a, 3b, 3c, 3d Feed rolls 4a, 4b, 4c, 4d Reversing rolls 5a, 5b 5c, 5d Anode 6 Guide roll 7 Winding roll 8a, 8b Tension roll 9a, 9b Heating means

Claims (6)

While unwinding a resin film with a primary metal layer having a primary metal layer in which a base metal thin film and a copper thin film are laminated on one surface of a long resin film without using an adhesive, the roll is rolled to roll. Then, a copper secondary metal layer is formed on the surface of the primary metal layer by electroplating, and the obtained long metallized resin film is applied with a tension of 2.4 to 4.9 N / mm ² per unit cross-sectional area. A method for producing a metallized resin film, wherein the heat treatment is performed at a temperature of 100 to 150 ° C., and then the film is wound on a take-up roll so that the secondary metal layer is face up.   The method for producing a metallized resin film according to claim 1, wherein the heat treatment heats a surface side of the metallized resin film that does not have a secondary metal layer.   The method for producing a metallized resin film according to claim 1, wherein the electroplating and the heat treatment are continuously performed.   The method for producing a metallized resin film according to claim 1, wherein the heat treatment is performed by far infrared heating. The said primary metal layer consists of the base metal thin film which consists of a nickel thin film or nickel alloy thin film formed by dry plating, and the copper thin film laminated | stacked on the surface by dry plating, The any one of Claims 1-4 characterized by the above-mentioned. A method for producing a metallized resin film according to claim 1. The said long resin film consists of polyimide films, The manufacturing method of the metallized resin film in any one of Claims 1-5 characterized by the above-mentioned.

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