JP2007227978A - Film carrier tape for mounting electronic components - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a film carrier tape for mounting electronic components, which is small in initial warpage and does not increase its amount of warpage with time. <P>SOLUTION: The film carrier tape for mounting electronic components has a flexible insulating film, and a wiring pattern which is formed by etching metal foil laminated on one surface of the flexible insulating film. The film carrier tape for mounting electronic components is characterized that, when initial amount of warpage X (however, X is an amount more than 0) measured by the focus depth method is not more than 3% with respect to the tape width and an amount of warpage similarly measured after holding the film carrier tape for mounting electronic components for 120 Hrs under conditions of temperature 25°C and humidity 60% is Y, the amount of warp variation W represented by an equation W=(Y-X)/X is not more than 2.5. It becomes difficult to occur mounting defect of a device and tape conveying defect in mounting by using the film carrier tape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a film carrier tape for mounting electronic components (TAB (Tape Automated Bonding) tape, T-BGA (Tape Ball Grid Array) tape, ASIC (Application Specific Integrated Circuit) tape, etc.)) and a tape that hardly warp and deform. On how to do.

  In order to incorporate electronic components such as semiconductor ICs and LSIs into electronic devices, film carrier tapes for mounting electronic components are used. In such a film carrier tape for mounting electronic components, a conductor foil is laminated on the surface of a long insulating film, and then a photoresist is applied to the surface of the conductor foil, and a desired wiring pattern is applied to the photoresist. After the exposure and removal of excess photoresist, the conductive foil is etched using the remaining photoresist as a masking material to form a wiring pattern made of the conductive foil on the surface of the insulating film.

Such film carrier tapes for mounting electronic components include TAB (Tape Automated Bonding) tape and T-BGA (Tape Ball Grid Array) due to differences in mounting methods of electronic components.
There are tapes. Recently, with the high integration of electronic components, the wiring pattern formed on the film carrier tape on which such electronic components are mounted has also become very fine pitch. Therefore, bumps and film carriers of highly integrated electronic components have been developed. Alignment with tape leads is becoming very difficult. For example, if warp deformation or the like occurs in the film carrier tape, the lead position and the bump position do not coincide with each other, and in such a case, mounting of an electronic component is defective.

  By the way, a film carrier tape for mounting electronic components is formed by forming a wiring pattern with a conductive metal foil such as a copper foil laminated on the surface of a flexible insulating film such as a polyimide film. A solder resist layer is usually formed on the surface of the wiring pattern so as to protect the wiring pattern except for the lead portion.

  Thus, the electronic component mounting film carrier tape has a configuration in which an insulating film, a conductive metal foil, and a solder resist are laminated, and these physical properties are completely different. Deformation due to slight environmental changes such as reaction shrinkage, temperature and humidity of tape storage environment. For example, in the case of a film carrier tape for mounting electronic components in which the insulating film is a polyimide film and the conductive metal foil is a copper foil, the polyimide has a property of absorbing water and expanding due to water absorption. However, copper foil does not absorb water and does not change its dimensions depending on moisture. Therefore, when the film carrier tape for mounting electronic components in which the wiring pattern made of copper foil is formed on the surface of the flexible insulating film made of polyimide is left in the room, the polyimide film absorbs and expands and the wiring pattern is formed. It tends to warp and deform in the width direction with the side inside. In addition, many solder resists undergo reaction shrinkage when cured, and therefore, after applying the solder resist, warping deformation stress may occur so that the solder resist application surface side is inward when cured. . When the thickness of the insulating film is about 80 to 150 μm as in the prior art, the self-form retaining property of the insulating film itself has acted to resist the deformation stress to some extent. . However, there is a high demand for weight reduction and miniaturization in recent electronic products, and the film carrier tape for mounting electronic components used for such demand is gradually becoming thinner. Recently, it is 75 μm or less as a flexible insulating film. Very thin insulating films are being used. And by using such a thin insulating film, there exists a tendency for the curvature deformation of the film carrier tape for electronic component mounting to become large.

  In film carrier tape for mounting electronic components, it is an important characteristic that there is little warping deformation immediately after the tape is manufactured, but what is the process of manufacturing a film carrier tape for mounting electronic components and the process of mounting devices etc. on this tape? In general, this is a completely different process, and the warp deformation as described above is manifested as a device mounting failure in the process of mounting the device on the tape, not in the tape manufacturing process.

  Therefore, even if the amount of warping deformation immediately after manufacturing the film carrier tape for mounting electronic components is small, if the amount of warping deformation increases before the device is mounted on this tape, the warping removal performed when manufacturing the tape is performed. Processing becomes completely meaningless. Despite these facts, as shown below, various proposals have been made with the main point of improvement being to remove the warp of the tape when manufacturing a film carrier tape for mounting electronic components. However, it has not been improved from the viewpoint of reducing the amount of change in warpage after the device is mounted.

  For example, in claim 2 of JP-A-6-283576 (Patent Document 1), in the production of a flexible circuit board in which a pattern is formed on a resin-based film, thermosetting is applied for the purpose of circuit protection. An invention of a method for producing a flexible circuit board that can be mounted in a state in which no warpage occurs is disclosed by printing a mold solder resist, winding the solder resist coating side outward, and heating and curing in a coil state.

Japanese Patent Laid-Open No. 11-111781 (Patent Document 2) discloses that a film carrier tape for semiconductor IC is heated while applying a reverse warp in the width direction, or a reverse warp in the width direction is applied to the tape while heating. A method of reducing the warp in the width direction of the film carrier tape by releasing the reverse warp after constraining and cooling is disclosed. In any of the warping removal methods described in these publications, warpage occurs in the film carrier tape due to reaction shrinkage when the solder resist is cured. Curing the solder resist with the film deformed on the opposite side cancels out the warpage caused by the hardening of the solder resist and the reverse warp applied to the tape, resulting in a reduction in the amount of warping of the film carrier tape. Is the method.

  Thus, the amount of warpage of the film carrier tape immediately after production is reduced by offsetting the warpage due to the hardening of the solder resist and the applied reverse warpage. However, the curing reaction of the solder resist is not completely completed at the time of heating for curing, but proceeds slightly after heating. As the solder resist curing reaction progresses, the solder resist shrinks with time, so even a film carrier tape that has been warped at the time of manufacture until the device is mounted. New warping deformation may occur in the meantime.

In addition, the cause of the warp occurring in the film carrier tape is not only the cure shrinkage of the solder resist as described above, but the warp of the film carrier tape is, for example, the hygroscopic expansion of a polyimide film widely used as an insulating film. The warp caused by such a cause cannot be eliminated by the conventional method. Further, when the film thickness is 50 μm or less, a new problem that cracks occur in the solder resist may occur when the reverse warp is applied.
JP-A-6-283576 JP 11-111781 A

  An object of the present invention is to provide a method for producing a film carrier tape for mounting an electronic component in which the initial warpage is small and the warpage amount does not increase with time. A further object of the present invention is to provide a film carrier tape for mounting electronic components that has a small amount of warpage change over time.

An electronic component mounting film carrier tape of the present invention includes a flexible insulating film and a wiring pattern formed by etching a metal foil laminated on one surface of the flexible insulating film. A film carrier tape for mounting, wherein the initial warpage amount X (where X is an amount exceeding 0) of the electronic component mounting film carrier tape measured by a depth of focus method is 3% with respect to the width of the tape The warpage change represented by the following formula when Y is the warpage amount measured in the same manner after the electronic component mounting film carrier tape is held for 120 hours at a temperature of 25 ° C. and a humidity of 60%: The quantity W is 2.5 or less.
W = (Y−X) / X
An electronic component mounting film carrier tape of the present invention includes a flexible insulating film and a wiring pattern formed by etching a metal foil laminated on one surface of the flexible insulating film. A film carrier tape for mounting is wound around a reel together with a flat resin film (flat spacer), and the wound film carrier tape for mounting an electronic component is held under reduced pressure.

  The film carrier tape for mounting electronic components of the present invention is usually coated with a solder resist layer on the formed wiring pattern leaving the lead portion. The film carrier tape for mounting an electronic component of the present invention is formed by forming a wiring pattern on the surface of a flexible insulating film, and then applying a solder resist on the wiring pattern to leave a lead portion, followed by curing. The film carrier tape is wound around a reel together with a flat spacer made of a resin film having flat front and back surfaces, and the film carrier tape wound around the reel together with the flat spacer is held for a predetermined time under reduced pressure. . After being held under reduced pressure in this way, the film carrier tape for mounting electronic components is usually returned to normal pressure in a wound state and used. In the process of returning to normal pressure after being held under such reduced pressure, the electronic component mounting film carrier tape is returned to the normal humidity environment, and the insulating film absorbs moisture. The film carrier tape is less likely to warp and deform.

  That is, when the initial warpage amount of the film carrier tape for electronic component mounting manufactured in this way is measured by the depth of focus method, the initial warpage amount with respect to the tape width is small, and the amount of warpage change with time with respect to the initial warpage amount is very small. .

  Next, the film carrier tape for mounting electronic parts of the present invention and the manufacturing method thereof will be specifically described with reference to the drawings.

  As shown in FIGS. 1 and 2, an electronic component mounting film carrier tape 1 according to the present invention includes a flexible insulating film 10 and a wiring pattern formed on one surface of the flexible insulating film 10. Further, a solder resist 18 is applied to the surface of the wiring pattern 14 leaving a lead portion connected to a device or the like.

The flexible insulating film 10 used in the present invention is made of an insulating resin film having flexibility. In addition, the flexible insulating film 10 has a chemical resistance that is not affected by such chemicals because it comes into contact with an acid during etching, and a heat resistance that does not deteriorate due to heating during bonding. ing. Examples of the material for forming such a flexible resin film include polyester, polyamide, and polyimide. In particular, in the present invention, it is preferable to use a film made of polyimide.

Examples of the polyimide film constituting the flexible insulating film 10 include wholly aromatic polyimide synthesized from pyromellitic dianhydride and aromatic diamine, biphenyltetracarboxylic dianhydride and aromatic diamine. Examples include wholly aromatic polyimides having a biphenyl skeleton to be synthesized. In particular, in the present invention, a wholly aromatic polyimide having a biphenyl skeleton (eg, trade name: Upilex, manufactured by Ube Industries, Ltd.) is preferably used. The thickness of the flexible insulating film 10 is usually 25 to 125 μm, preferably 75 μm.
Hereinafter, it is particularly preferably in the range of 25 to 75 μm, and more preferably 50 μm or less.
When polyimide is used as such a flexible insulating film, this polyimide is less than about 3%, but has a water absorption property, and the polyimide has the property of expanding when absorbed. .

  When the flexible insulating film 10 used in the present invention has a device hole 20, a sprocket hole 21, an outer lead hole 22, and a bent portion, a flex slit (not shown) or the like is punched at the bent position. Is formed. The wiring pattern 14 is formed by etching a metal foil laminated on at least one surface of the flexible insulating film 10 in which the predetermined holes 20, 21, 22,. . The metal foil is laminated on at least one surface of the flexible insulating film 10 with or without an adhesive. Here, when the metal foil is stuck using an adhesive, the adhesive layer 12 is formed using an insulating adhesive.

  The adhesive used here needs to have characteristics such as heat resistance, chemical resistance, adhesive strength, and flexibility. Examples of adhesives having such properties include epoxy adhesives, polyimide adhesives, and phenolic adhesives. Such an adhesive may be modified with a urethane resin, a melamine resin, a polyvinyl acetal resin, or the like, or the epoxy resin itself may be rubber-modified. Such adhesives are usually thermosetting.

  The thickness of the adhesive layer 12 is usually 8 to 23 μm, preferably 10 to 21 μm. When an adhesive is used, the adhesive layer 12 may be provided by applying an adhesive on the surface of the flexible insulating film 10, or may be provided by applying an adhesive on the surface of the metal foil. good.

  In this invention, when laminating | stacking metal foil on the flexible insulating film 10, it can also laminate | stack without using an adhesive agent. In addition to the method using the metal foil as described above, the metal layer can be formed by, for example, vapor deposition or plating. Furthermore, when forming a metal layer by such a vapor deposition method or a plating method, an ultrathin metal layer is formed in advance using an ultrathin metal foil, and the vapor deposition method or the plating method is formed on the ultrathin metal layer. A metal layer having a desired thickness may be formed by depositing a metal.

  The metal foil used in the present invention is made of a conductive metal, and examples of such a metal foil include a copper foil and an aluminum foil. In the present invention, it is particularly preferable to use a copper foil as the metal foil. The copper foil includes an electrolytic copper foil and a rolled copper foil. In the present invention, any copper foil can be used. However, when manufacturing a film carrier tape for mounting a fine pitch electronic component, the metal foil It is preferable to use an electrolytic copper foil.

As the electrolytic copper foil used here, an electrolytic copper foil having a thickness usually used for manufacturing a film carrier tape for mounting electronic components can be used. For production, the average thickness is usually in the range of 6 to 150 μm, preferably 6 to 75 μm, particularly preferably 8 to 75 μm, more preferably 8 to 5 μm.
An electrolytic copper foil in the range of 0 μm is used. By using the electrolytic copper foil having such an average thickness, an inner lead having a narrow pitch width can be easily formed.

  In the present invention, a base film is manufactured by laminating a layer made of metal (a metal foil layer, a metal plating layer, a metal vapor deposition layer, or a composite metal layer thereof) on the flexible insulating film as described above. Next, a photoresist is applied to the metal layer surface of the base film, a predetermined wiring pattern is baked on the photoresist, an unnecessary photoresist is removed to form a predetermined pattern on the metal layer surface of the base film, The metal layer is etched using this pattern as a masking material.

  That is, a photoresist is applied to the surface of the metal layer of the base film, and a predetermined wiring pattern is exposed and baked to form a soluble part and an insoluble part in the aqueous medium. For example, a masking material made of an insoluble photoresist can be formed on the surface of the metal layer. Here, the masking material made of an insoluble photoresist may be formed from a photoresist that is cured by exposure, and conversely, it can be dissolved in a specific solvent such as an aqueous medium by exposure. It can also form by removing the photoresist of the part solubilized with the specific solvent, after exposing using the photoresist which becomes.

  When the base film thus masked with the photoresist is brought into contact with the etching solution, the unmasked portion of the metal elutes and the masked portion of the metal remains on the flexible insulating film. A wiring pattern made of a metal foil (or metal layer) that has not been eluted is formed on the conductive insulating film. As the etching solution used here, a commonly used acidic etching solution can be used.

  In the wiring pattern thus formed, each pitch width of the inner leads is usually 20 to 500 μm, preferably 25 to 100 μm. The present invention is particularly applicable to a film carrier tape for mounting electronic components having a fine pitch of 30 to 80 μm. It is highly useful. In addition, the masking material (insoluble photoresist) after etching in this way can be removed by washing with, for example, an alkaline washing solution.

  In the present invention, usually, after a predetermined wiring pattern is formed in this way, the solder resist 18 is applied except for the tip of the inner lead 15 and the tip of the outer lead 16 to be plated in the next step. The solder resist coating solution used in the present invention is a coating solution having a relatively high viscosity in which a curable resin is dissolved or dispersed in an organic solvent.

  The curable resin contained in such a solder resist coating liquid is an epoxy resin, an elastomer modified product of an epoxy resin, a urethane resin, an elastomer modified product of a urethane resin, a polyimide resin, an elastomer modified product of a polyimide resin, and an acrylic resin. It is preferable to contain at least one resin component selected from the group consisting of resins. It is particularly preferable to use a modified elastomer.

  In the present invention, in addition to the resin components as described above, the solder resist coating solution includes substances such as curing accelerators, fillers, additives, thixotropic agents and solvents that are usually added to the solder resist coating solution. Can be added. Furthermore, in order to improve the characteristics such as flexibility of the solder resist layer, it is possible to blend fine particles having elasticity such as rubber fine particles.

  Such a solder resist coating solution can be applied using screen printing technology. The solder resist coating solution is applied except for portions that are normally plated in the next step, such as the inner lead portion and the outer lead portion. The average coating thickness of the solder resist 18 is usually in the range of 1 to 80 μm, preferably 5 to 50 μm.

  After the solder resist is applied in this manner, the solder resist is usually cured by heating, and usually shrinks with this curing reaction. After applying the solder resist while leaving the lead portion in this way, the lead portion exposed from the solder resist is plated. Such plating processes include tin plating process, gold plating process, nickel base gold plating process, nickel plating process, silver plating process, and solder plating process. In the present invention, these processes can be used alone or in combination. it can. In the present invention, tin plating is particularly preferable. The average thickness of the plating layer thus formed is preferably in the range of 0.01 to 0.6 μm.

  The film carrier tape for mounting electronic components manufactured as described above is shown in FIG. 2 due to various factors such as shrinkage due to reaction hardening of the solder resist and / or expansion due to water absorption of the flexible insulating film. As indicated by the arrows, the warp deformation occurs with the solder resist 18 application surface facing inward. In the present invention, the film carrier tape for mounting electronic components thus manufactured is wound around a reel together with a flat spacer and held under a reduced pressure condition for a predetermined time.

  The flat spacer used in the present invention is usually formed from a resin film or the like. Here, as the resin forming the flat spacer, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN): polyolefins such as polyethylene, polypropylene and LLDPE; polyamides, polyimides, fluororesins (Teflon (registered trademark) TM) Examples thereof include impregnated glass cloth and fluororesin (Teflon (registered trademark) TM) impregnated paper. The thickness of the flat spacer formed of such a resin is usually 50 μm or more, preferably 50 to 200 μm, particularly preferably 75 to 150 μm. By using the flat spacer having such a thickness, the initial warpage amount of the film carrier tape for mounting electronic components of the present invention is reduced, and the change in warpage amount (warpage change amount) with time is also reduced. As such a flat spacer, a resin film having a tape width equal to or equal to the width of the wound electronic component mounting film carrier tape or ± 4 mm of the tape width is preferably used. The film carrier tape for mounting electronic components has a width of 30 to 120 mm, and is usually formed according to standards such as 35 mm, 48 mm, and 70 mm. For example, it is wound together with a film carrier tape for mounting electronic components of 70 mm. As the flat spacer to be rotated, a resin film having a tape width in the range of 66 to 74 mm can be used.

  Such a flat spacer has a flat front and back surface, and is different from a spacer having unevenness on the side edge part conventionally used when winding a film carrier tape for mounting electronic components on a reel. It is. In the present invention, the flat spacer and the electronic component mounting film carrier tape as described above are wound around a reel, preferably a metal reel, and are held under reduced pressure while being wound around the metal reel via the flat spacer. The In this case, the film carrier tape for mounting electronic components can be wound with a flat spacer so that the surface on which the wiring pattern is formed faces the core side of the reel, and the side on which the wiring pattern is formed is outside. It can also be wound so that it faces.

The film carrier tape for mounting electronic components wound on a metal reel with a flat spacer as described above is usually 0.0001 to 0.8 atm, preferably 0.005 to 0.5 atm, under reduced pressure. Is held for 0.1 to 100 hours, preferably 0.5 to 48 hours. The electronic component mounting film carrier tape wound around the metal reel with the flat spacer as described above is usually held in a desiccator (decompression chamber) for a predetermined time. Such a desiccator is not particularly limited as long as the inside can be maintained under a reduced pressure as described above, but the desiccator may have a heating or heating means.

  The warp amount (initial warp amount X) measured by the depth of focus method for the film carrier tape for mounting an electronic component of the present invention produced by holding the product under reduced pressure for a predetermined time as described above is 3% with respect to the tape width. Hereinafter, it is preferably in the range of more than 0 and 1% or less. That is, the film carrier tape for mounting electronic parts of the present invention has very little warping immediately after production. However, the amount of warpage (initial warpage) of the tape when the film carrier tape for electronic component mounting that is normally manufactured is stored under reduced pressure and then returned to normal pressure in a wound state is somewhat less than zero. Indicates a large value.

Then, when the warpage amount measured in the same manner after holding the electronic component mounting film carrier tape at a temperature of 25 ° C. and a humidity of 60% for 120 hours is Y, The warpage change amount W represented by the relationship (W = (Y−X) / X) is 2.5 or less, preferably 2.0 or less, and particularly preferably 1 or less. Even if the film carrier tape for mounting electronic parts has a small amount of warping immediately after production, the device cannot be mounted if the amount of warping when the device is mounted on the tape is large. Therefore, what actually becomes a problem in the film carrier tape for mounting electronic components is not the amount of warping immediately after manufacturing but the amount of warping during mounting. And the electronic component mounting film carrier tape of the present invention not only has a very small initial warpage amount, but the small warpage amount hardly increases with time, so the electronic component mounting film carrier tape of the present invention should be used. Therefore, when the device is mounted, the position of the bump electrode of the device and the position of the lead coincide with each other, so that mounting failure is unlikely to occur. In addition, poor tape conveyance during mounting is unlikely to occur. FIG. 3 shows an example of the amount of warp change over time of a film carrier tape for mounting electronic components having a tape width of 70 mm. As shown in FIG. 3, by winding on a metal reel together with a flat spacer and holding under reduced pressure, the initial warpage amount is small and the warpage amount hardly changes with time, and the temperature is 25 ° C. and the humidity is 60%. That is, even when held for 120 hours under conditions very close to normal conditions for holding a film carrier tape for mounting electronic components, the amount of warping is very small.

  In the present invention, the depth-of-focus method for measuring the amount of warping refers to an apparatus equipped with a microscope capable of measuring a focal length, as shown in FIG. The focal length (a) of the highest position of the film carrier tape for mounting electronic components is measured, and the difference (b−a) between this focal length (a) and the focal length (b) with respect to the upper surface of the measurement substrate is measured. ), And this value is used as the warpage amount (ba) of the film carrier tape for mounting electronic components.

  The initial warping amount is a film carrier tape for mounting an electronic component immediately after being wound around a metal reel together with a flat spacer as described above, held under a reduced pressure for a predetermined time, and then returned to normal pressure while being wound. (This initial warp amount is assumed to be X). Normally, the measurement of the amount of warpage uses a measurement sample collected through the operation of taking out the reel from the decompression chamber into the room at normal pressure, but this requires a few minutes or less. The amount of warping hardly changes during collection.

Thus, the film carrier tape for mounting electronic components is returned to the normal pressure and humidity condition by being taken out from the decompression chamber and held in the room while being wound around the reel. Therefore, the amount of warpage measured immediately after being held for a predetermined time under reduced pressure as described above and taken out from the decompression chamber becomes the smallest amount of warpage. However, this electronic component mounting film carrier tape is a laminated body in which a large number of materials such as a flexible insulating film, a wiring pattern, and a solder resist are laminated. It is very unlikely that there will be no state at all (that is, X will not be 0 in the following equation).

The warpage change amount defined in the present invention is measured in the same manner as described above after the electronic component mounting film carrier tape thus taken out from the decompression chamber is held at a temperature of 25 ° C. and a humidity of 60% for 120 hours. (This amount of warpage is assumed to be Y), and is the amount of change (W) over time of the warpage obtained by the following equation.
W = (Y−X) / X
In the film carrier tape for mounting electronic components of the present invention, the W is 2.5 or less, preferably 2.0 or less, particularly preferably more than 0 and 1 or less.

  On the other hand, the amount of warp change W of the film carrier tape for mounting electronic parts, which is wound through a spacer having irregularities on the side edges and held under reduced pressure, without using a flat spacer, is 2.5. In many cases, it is 4 or more. Thus, the film carrier tape for mounting electronic parts of the present invention has a small change in warpage over time. In the case of a film carrier tape (for example, W = 5) for mounting electronic parts whose warpage variation W greatly exceeds 2.5 shown in FIG. 3, for example, the tape width is 70 mm, the cumulative pitch length of the inner leads is 10 mm, the inner leads Assuming that the pitch width is 50 μm, the position of the bump electrode and the position of the inner lead will be displaced by about 70 μm at the maximum after 120 hours have elapsed, and such a deviation width exceeds the pitch width of the inner lead. Therefore, it is extremely difficult to implement a device while correcting this gap. On the other hand, in the film carrier tape for mounting electronic components according to the present invention in which the warpage variation W shown in FIG. 3 is 2.5 or less, the deviation between the position of the bump electrode and the position of the inner lead after 120 hours is maximum. However, the lead misalignment is about 25 μm. When the device is mounted, the position can be corrected by mechanically correcting the tape, for example, and the device can be mounted satisfactorily.

  As described above, the detailed reason why the film carrier tape for mounting electronic components of the present invention has a small initial warpage and a small amount of warpage change with time is unknown, but a film for mounting electronic components using a flat spacer is unknown. The carrier tape is wound, and in this state, the moisture in the flexible insulating film evaporates by holding it under reduced pressure for a predetermined time, and the flexible insulating film contracts. Even if it returns, the state that the flexible insulating film contracted due to the evaporation of moisture in the flexible insulating film is maintained, and the tape is returned to normal pressure as it is, through the flat spacer. Film carrier tape for electronic component mounting wound by winding is wound, the initial warpage amount is reduced, and the stress due to this winding is the film for mounting electronic component Remaining in Yariatepu believed to be due to suppresses the occurrence of over time warping.

The film carrier tape for mounting electronic components of the present invention is not limited to the TAB tape which is a film carrier tape for mounting electronic components as shown in FIG. 1, but has a T-BAG tape and an outer lead for output. For example, a film carrier tape for mounting electronic parts for liquid crystal, a CSP tape, a film carrier tape for wire bonding, and the like may be used.

  The film carrier tape for mounting electronic components manufactured by the method of the present invention has a small initial warpage amount by winding the film carrier tape for mounting electronic components together with a flat spacer and holding it under a reduced pressure for a predetermined time. The amount of warpage hardly increases over time. Therefore, the use of the electronic component mounting film carrier tape manufactured by the method of the present invention makes it difficult to cause device mounting failure and tape transport failure during mounting.

Next, although an Example is shown and the present invention is explained still in detail about the film carrier tape for electronic parts mounting of the present invention, the present invention is not limited by these.
[Example 1]
Device holes, sprocket holes, and outer lead cutting slits were formed on a polyimide film having a width of 70 mm and a thickness of 50 μm by punching. Next, an epoxy adhesive was applied to the polyimide film surface, and an electrolytic copper foil having a thickness of 18 μm was adhered.

Further, a photoresist was applied on the copper foil, the photoresist was exposed, and further etched to form a wiring pattern on the copper foil. The lead pitch width in the formed wiring pattern is 50 μm. After the urethane solder resist was applied to the wiring pattern thus formed, the solder resist was cured by heating to a temperature of 80 to 140 ° C. over a period of 2.5 hours.

  After forming the solder resist layer in this way, this film was transferred to an electroless tin plating tank, and a tin plating layer was formed with a thickness of 0.2 μm on the surface of the wiring pattern (inner lead and outer lead) not coated with the solder resist. . Separately, a polyethylene terephthalate (PET) film having a thickness of 125 μm was prepared. The width of this PET film is 70 mm, the same as the width of the TAB tape, and both the front and back surfaces are smooth surfaces.

  The PET film and the TAB tape as described above were overlapped and wound around the metal reel so that the wiring pattern of the TAB tape and the solder resist coating surface faced the core side of the metal reel. The TAB tape wound around the metal reel together with the PET film was put in a desiccator, and the inside of the desiccator was depressurized to 0.01 atm.

  Under such reduced pressure conditions, the TAB tape was held for 24 hours. After 24 hours, the TAB tape is taken out from the desiccator, a part thereof is cut out, and the cut sample is placed on the measurement board of the apparatus shown in FIG. 4 so that the wiring pattern faces the measurement board surface. When measuring the focal length of the highest portion of this, this focal length was 2 mm. The focal length of the measurement substrate surface in this apparatus is 1 mm, the initial warpage amount (X) of this TAB tape is 1 mm, and this initial warpage amount corresponds to 1.4% with respect to the tape width. .

The TAB tape sample was left in a room adjusted to 25 ° C. and 60% humidity, and the amount of warpage was measured every predetermined time. The amount of warpage is shown in FIG. The warpage amount (Y) after standing for 120 hours was 3 mm, and the warpage change amount (W) obtained from these values by the following equation was 2.
W = (Y−X) / X
[Reference Example 1]
In Example 1, a TAB tape was produced in the same manner except that it was wound around a metal reel through a conventional spacer (embossed spacer) having irregularities on the edge instead of a flat spacer made of PET film. This TAB tape was put into a desiccator in the same manner as in Example 1, and the inside of this desiccator was decompressed to 0.01 atm in the same manner as in Example 1 above.

  Under such reduced pressure conditions, the TAB tape was held for 24 hours. After 24 hours, the TAB tape was taken out from the desiccator and left in the same manner as in Example 1 in the amount of initial warp (X) and in the same conditions as in Example 1 (25 ° C, adjusted to 60% humidity), The amount of warpage of the TAB tape with time was measured. The initial warpage amount (X) of this TAB tape is 1.0 mm, and this initial warpage amount corresponds to 1.4% with respect to the tape width, which is almost equivalent to the TAB tape manufactured in Example 1 above. It was.

  Moreover, the amount of warpage with time measured as described above was measured, and the results are also shown in FIG. From this measurement result, the amount of warpage (Y) after lapse of 120 hours under the same conditions as in Example 1 (25 ° C., room adjusted to 60% humidity) was 8 mm. When the amount of change in warp (W) after 120 hours was determined from these values, W was 7.

Thus, the TAB tape manufactured in the same manner as in Example 1 except that a conventional spacer having irregularities at the edges was used without using a flat spacer, the amount of warpage change (W) after 120 hours had elapsed. large. That is, when the TAB tape obtained in Reference Example 1 and Example 1 is compared, the TAB tape is wound through a flat spacer and held under reduced pressure, and then returned to normal pressure in the wound state. This shows that there is not much difference in the initial warpage amount, but there is a great difference in the warpage change amount with time.
[Comparative Example 1]
When manufacturing the TAB tape shown in Example 1, the TAB tape was manufactured by applying a reverse warp using the warp removing device having a barrel roll used in Example 1 of JP-A-11-11178. Thus, when the TAB tape which carried out the reverse curvature using the curvature removal apparatus which has a tal roll was observed in detail, the crack had arisen in the hardened soldering resist layer. Moreover, the lead width of the TAB tape manufactured here is 25 μm, and the TAB tape having such a thinned lead is subjected to warp removal using a barrel roll, so that the thin wire as described above. Many deformed inner leads were generated.

FIG. 1 is a view showing an example of a film carrier tape for mounting electronic components. 2 is an XX cross-sectional view of the electronic component mounting film carrier tape of FIG. 1. FIG. 3 is a graph showing the amount of warpage of the TAB tape of the present invention manufactured in Example 1 and the TAB tape manufactured in Reference Example 1. FIG. 4 is an explanatory diagram of a focal depth measurement method that is a warp amount measurement method employed in the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Flexible insulating film 12 ... Adhesive 14 ... Wiring pattern 15 ... Inner lead 16 ... Outer lead 18 ... Solder resist 20 ... Device hole 22 ... Outer lead hole 21 ... Sprocket hole

Claims (4)

An electronic component mounting film carrier tape comprising: a flexible insulating film; and a wiring pattern formed by etching a metal foil laminated on one surface of the flexible insulating film, the electronic component The initial warpage amount X (where X is an amount exceeding 0) measured by the depth of focus method for the mounting film carrier tape is 3% or less with respect to the width of the tape, and the electronic component mounting film carrier The warpage change amount W represented by the following formula is 2.5 or less when the warpage amount measured in the same manner after holding the tape at a temperature of 25 ° C. and a humidity of 60% for 120 hours is Y or less. Film carrier tape for mounting electronic components.
W = (Y−X) / X   2. The film carrier tape for mounting electronic parts according to claim 1, wherein a solder resist layer is coated on the wiring pattern leaving a lead portion.   3. The film carrier tape for mounting electronic parts according to claim 1, wherein the flexible insulating film is a polyimide film having a width of 30 to 120 mm.   4. The film carrier tape for mounting electronic parts according to claim 3, wherein an average thickness of the polyimide film as the flexible insulating film is 75 [mu] m or less.

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