Cover tape and electronic component packaging body

Abstract

To provide electronic component packaging body cover tape having a sealant layer comprising a conductive polymer in which blocking is suppressed without necessarily using a granular anti-blocking agent, and suitable adhesive strength is obtained.SOLUTION: There is disclosed electronic component packaging cover tape comprising a base material layer and a sealant layer provided at least on one side of the base material layer. In the cover tape, the sealant layer comprises a conductive polymer. A face on the side opposite to the base material layer being an exposed face. The peak density Spd defined by ISO25178 in the exposed face is 4,00,000 to 1,500,000 / mm2. Further, the root-mean-square slope Sdq defined by ISO25178 in the exposed face is 0.05 to 0.3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cover tape for packaging electronic components and an electronic component package, and more particularly to a cover tape for packaging electronic components and an electronic component package in which electronic components are packaged using the cover tape. [Background technology]

[0002] Electronic components such as transistors, diodes, capacitors, piezoelectric resistors, etc. are sometimes transported in the form of "electronic component packages" obtained by housing them in recesses in a carrier tape that has recesses formed therein capable of housing the electronic components to prevent damage, and then heat-sealing a cover tape to the carrier tape so as to seal the electronic components in the recesses. When the packaged electronic component is to be used, the cover tape in the electronic component package is peeled off and the electronic component is taken out of the recess.

[0003] Various studies have been conducted on the adhesiveness and peelability of the cover tape. For example, Patent Document 1 discloses that the peelability is optimized by focusing on the peel resistance ratio α between the maximum and minimum values ​​of the peel resistance between the carrier tape and the cover tape.

[0004] In addition, in order to protect the electronic components to be packaged, it is preferable that the cover tape has the property of easily dissipating generated static electricity (not easily charged). For this reason, there have been attempts to include a conductive material in a part of the layers constituting the cover tape. For example, Patent Document 2 describes that in a film for packaging electronic elements, which comprises a base layer, an intermediate layer, and a heat seal layer in this order, a conductive polymer is included in the intermediate layer, and an antistatic coating is provided on the surface of the base layer opposite to the intermediate layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-171393 A [Patent Document 2] International Publication No. 2012 / 079258 Summary of the Invention [Problem to be solved by the invention]

[0006] The present inventors have conducted a preliminary study into including a conductive polymer in the sealant layer of the cover tape in order to suppress static electricity buildup. However, in a preliminary study, blocking often occurred. That is, when the cover tapes were wound and stored for a certain period of time, the cover tapes often stuck together. It was speculated that the blocking occurred because the sealant layer became sticky or tacky due to the inclusion of a conductive polymer in the sealant layer.

[0007] It is known that anti-blocking agents such as inorganic particles are used to suppress blocking. However, there is a concern that the inclusion of an anti-blocking agent in the sealant layer may reduce the adhesive strength (also expressed as peel strength) of the cover tape to the carrier tape. Therefore, it is preferable to suppress blocking without using an anti-blocking agent such as inorganic particles, etc. Doing so is believed to result in a cover tape with appropriate adhesive strength.

[0008] The present invention has been made in view of the above circumstances. One of the objects of the present invention is to suppress blocking and obtain appropriate adhesive strength in a cover tape for packaging electronic components, the cover tape including a conductive polymer in a sealant layer, without necessarily using a particulate antiblocking agent. [Means for solving the problem]

[0009] The present inventors have completed the invention provided below and have solved the above problems.

[0010] 1. A cover tape for packaging electronic components, comprising a base layer and a sealant layer provided on at least one side of the base layer, The sealant layer includes a conductive polymer, The surface of the sealant layer opposite to the base material layer is an exposed surface, The peak density Spd of the exposed surface as defined by ISO 25178 is 400,000 to 1,500,000 / mm 2 and The cover tape has a root mean square slope Sdq, as defined by ISO 25178, of 0.05 to 0.3 on the exposed surface. 2. 1. The cover tape according to claim 1, The cover tape, wherein the conductive polymer comprises a polythiophene. 3. 1. or 2. A cover tape according to claim 1, The cover tape, wherein the conductive polymer is soluble or dispersible in an organic solvent. 4. A cover tape according to any one of 1. to 3., The cover tape, wherein the sealant layer comprises a styrene-based resin. 5. A cover tape according to any one of 1. to 4., The cover tape, wherein the sealant layer comprises a styrene-based elastomer. 6. A cover tape according to any one of 1. to 5., The cover tape further comprises an intermediate layer between the base layer and the sealant layer. 7. 6. The cover tape according to claim 6, The cover tape, wherein the intermediate layer comprises a polyethylene-based resin. 8. A cover tape according to any one of 1. to 7., The cover tape, wherein the sealant layer does not contain inorganic particles or contains inorganic particles in an amount of 1% by mass or less of the entire sealant layer. 9. A cover tape according to any one of 1. to 7., The cover tape, wherein the exposed surface has an arithmetic mean height Sa, as defined by ISO 25178, of 0.05 to 0.5 μm. 10. A carrier tape having electronic components housed in recesses and a cover tape according to any one of 1 to 9, An electronic component package in which the sealant layer is adhered to the carrier tape so as to seal the electronic component. Effect of the Invention

[0011] According to the present invention, in a cover tape for packaging electronic components that contains a conductive polymer in a sealant layer, it is possible to suppress blocking without necessarily using a particulate antiblocking agent, and it is also possible to obtain an appropriate adhesive strength. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a diagram illustrating an example of a layer structure of a cover tape. [Diagram 2] FIG. 2 is a diagram showing an example of a state in which a cover tape is bonded (heat sealed) to a carrier tape. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In all drawings, similar components are given similar symbols and descriptions thereof are omitted where appropriate. In order to avoid complexity, (i) when there are multiple identical components in the same drawing, only one of them will be given a symbol, and not all of them, or (ii) especially in Figure 2 and subsequent figures, components similar to those in Figure 1 will not be given a symbol again. All drawings are for illustrative purposes only. The shapes and dimensional ratios of each component in the drawings do not necessarily correspond to the actual objects.

[0014] In this specification, unless otherwise specified, the expression "X to Y" in the explanation of a numerical range means from X to Y. For example, "1 to 5% by mass" means "from 1% by mass to 5% by mass". In this specification, the term "(meth)acrylic" refers to a concept that includes both acrylic and methacrylic. The same applies to similar terms such as "(meth)acrylate."

[0015] <Cover tape> FIG. 1 is a schematic diagram showing an example of a layer structure of a cover tape (cover tape 10) for packaging electronic components according to this embodiment. The cover tape 10 includes a base layer 1 and a sealant layer 3 provided on at least one side of the base layer 1 . The cover tape 10 preferably comprises an intermediate layer 2 between the base layer 1 and the sealant layer 3 . The sealant layer 3 contains a conductive polymer. The surface of the sealant layer 3 opposite to the base layer 1 is an exposed surface. In other words, the surface of the sealant layer 3 opposite to the base layer 1 is in contact with air.

[0016] The peak density Spd, as defined by ISO 25178, of the exposed surface of the sealant layer 3 is 400,000 to 1,500,000 / mm 2 , preferably 450000 to 1400000 / mm 2 , and more preferably 500,000 to 1,300,000 / mm 2 It is. The root mean square slope Sdq of the exposed surface of the sealant layer 3, as defined by ISO 25178, is 0.05 to 0.3, preferably 0.055 to 0.280, and more preferably 0.060 to 0.250. It is.

[0017] The reason why blocking is suppressed in the cover tape 10 described above can be explained as follows. Just to be clear, the following explanation includes speculation. Furthermore, the present invention is not limited to the following explanation.

[0018] The peak density (Spd) is the density of the peaks per square millimeter on the surface of the object being measured. 2 This represents the number of peaks larger than a given size per pixel. If not specified, the given size is set to 5% of the height of the maximum amplitude of the contour surface. Spd is 400000 / mm 2 This means that there is a certain density of "protrusions" on the exposed surface of the sealant layer 3. This is thought to reduce the contact area between the base layer 1 and the sealant layer 3 when the cover tape 10 is wound, thereby suppressing blocking. On the other hand, if Spd is too large, problems other than the contact area may occur. For example, the cover tape or electronic component package may be image-inspected with a camera. In this case, if Spd is too large, there is a risk that the image inspection may be hindered. In addition, if Spd is too large, there is a concern that the cover tape may not be properly heat-sealed to the carrier tape, and appropriate adhesive strength may not be obtained. Therefore, in this embodiment, the upper limit of Spd is set to 1,500,000 / mm 2 It is set as follows.

[0019] The root mean square slope Sdq is an index calculated by taking the root mean square of the slope at all points of a defined area, and represents the average value of the local gradient of a surface. A perfectly flat surface has an Sdq of 0. Although the details are unclear, it is believed that an Sdq of 0.05 or more means that there is a moderate gradient on the surface of the sealant layer 3, resulting in few flat surfaces. This is believed to reduce the contact area between the base layer 1 and the sealant layer 3 when the cover tape 10 is wound, thereby suppressing blocking. On the other hand, if Sdq is too large, the unevenness or undulations of the sealant layer 3 may mesh with the unevenness or undulations that may exist on the surface of the sealant layer 1, which may cause blocking. Also, if Sdq is too large, there is a concern that the cover tape may not be properly heat-sealed to the carrier tape, and appropriate adhesive strength may not be obtained. Therefore, in this embodiment, the upper limit of Sdq is set to 0.3.

[0020] Both Spd and Sdq are indices relating to the surface properties of the sealant layer 3. In the cover tape 10, these two indices are both optimized, so that blocking is suppressed and an appropriate adhesive strength is obtained when heat-sealed to a carrier tape. As far as the inventors have studied, even if one of Spd and Sdq is optimized, blocking may be more likely to occur or an appropriate adhesive strength may not be obtained if the other is not optimized.

[0021] The Spd of the cover tape 10, i.e., the exposed surface of the sealant layer 3, is 400,000 to 1,500,000 / mm 2 A cover tape in which the exposed surface of the sealant layer 3 has an Sdq of 0.05 to 0.3 can be manufactured by an appropriate manufacturing method. A preferred manufacturing method is a manufacturing method in which, in the manufacturing process of (i) preparing a laminate including a base layer 1 and an intermediate layer 2, and (ii) applying a coating liquid for forming a sealant layer to the surface of the intermediate layer 2, a certain amount of time is left between (i) and (ii) to age the laminate including the base layer 1 and the intermediate layer 2. By employing such a manufacturing method, the cover tape 10 can be easily manufactured. Furthermore, if the coating liquid for forming the sealant layer contains a styrene-based resin, the cover tape 10 can be manufactured even more easily. The manufacturing method and materials used for the cover tape 10 will be described in detail later.

[0022] The explanation regarding the cover tape 10 will continue.

[0023] [Base material layer 1] There are no particular limitations on the material that constitutes the base material layer 1. Any film can be used as long as it has the mechanical strength to withstand the external force applied to the cover tape 10 and the heat resistance to withstand the heat during heat sealing.

[0024] Specific examples of materials constituting the base layer 1 include ester resins, amide resins, olefin resins, acrylate resins, methacrylate resins, imide resins, carbonate resins, ABS resins, etc. Among these, ester resins and olefin resins are preferred as materials constituting the base layer 1, and polyethylene terephthalate and polyethylene, which can improve mechanical strength, are particularly preferred. The base layer 1 may contain only one resin, or may contain two or more resins.

[0025] The film used to form the base layer 1 may be a stretched film, or a film stretched in a uniaxial or biaxial direction. From the viewpoint of improving the mechanical strength of the cover tape 10, a film stretched in a uniaxial or biaxial direction is preferable.

[0026] The substrate layer 1 may be a single layer or a multilayer. The base layer 1 may contain an antistatic agent from the viewpoint of reducing the amount of static electricity generated when the carrier tape is peeled off. In addition, an antistatic layer may be provided as one layer of the base layer on the surface of the base layer 1 opposite to the surface on which the intermediate layer 2 is provided.

[0027] The thickness of the base layer 1 is, for example, 6 to 35 μm, preferably 7 to 33 μm, and more preferably 8 to 30 μm. Since the base layer 1 is not too thick, the rigidity of the cover tape is not too high. Even if a torsional stress is applied to the carrier tape after sealing, the cover tape 10 follows the deformation of the carrier tape, reducing the possibility of peeling off. Since the thickness of the base material layer 1 is not too thin, it is easy to make the mechanical strength of the cover tape 10 suitable. Furthermore, even when the cover tape 10 is peeled off from the carrier tape at high speed, the possibility that the cover tape 10 will break can be reduced.

[0028] [Middle layer 2] The intermediate layer 2 is provided mainly for the purpose of improving the cushioning properties of the cover tape 10. By improving the cushioning properties of the cover tape 10, the pressure of the sealing iron during heat sealing can be more easily and firmly transmitted to the cover tape 10. This can further improve the adhesion between the cover tape 10 and the carrier tape.

[0029] The material of the intermediate layer 2 is not particularly limited. Any material that can impart cushioning properties to the cover tape 10 can be used without particular limitation. For example, one or more selected from polyacrylic acid or its derivatives, polyacrylic acid ester or its derivatives, polyvinyl acetate or its derivatives, polystyrene resins, polyolefin resins, and polycyclic olefin resins, and copolymers thereof can be used. Among these, polyolefin resins are preferred, and polyethylene resins are more preferred. The intermediate layer 2 may contain only one resin, or may contain two or more resins. From the viewpoint of cushioning properties, it is particularly preferable that the intermediate layer 2 contains low-density polyethylene (LDPE), linear low-density polyethylene (L-LDPE), or the like.

[0030] The intermediate layer 2 may be a single layer or a multilayer. The thickness of the intermediate layer 2 is typically 10 to 50 μm, and preferably 15 to 45 μm, from the viewpoint of further improving the adhesion between the cover tape 10 and the carrier tape during heat sealing.

[0031] [Sealant layer 3] The sealant layer 3 is provided on at least one side of the base layer 1. When the intermediate layer 2 is present, the sealant layer 3 is provided on the side of the intermediate layer 2 opposite to the side in contact with the base layer 1. The sealant layer 3 is preferably in direct contact with the intermediate layer 2. The sealant layer 3 comes into contact with the carrier tape when the cover tape 10 is heat-sealed to the carrier tape. The sealant layer 3 softens or melts when heated by the sealing iron, and adheres to the carrier tape.

[0032] The sealant layer 3 preferably contains a thermoplastic resin. Specifically, the sealant layer 3 contains one or more resins selected from styrene-based resins, (meth)acrylic resins, olefin-based resins, urethane-based resins, and ester-based resins. Among these, styrene-based resins and (meth)acrylic resins are preferred from the viewpoint of good heat sealability and good dissolving or dispersing of conductive polymers. In particular, styrene-based resins are preferred because they are compatible with polystyrene-based materials, which are often used in carrier tapes, and are easy to increase adhesive strength. In addition, although the details are unclear, forming the sealant layer 3 using a styrene-based resin tends to make it easier to adjust the Spd and Sdq of the exposed surface of the sealant layer 3 to desired values.

[0033] Specific examples of styrene-based resins include polystyrene, styrene-butadiene copolymer (SB), styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butadiene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-methyl (meth)acrylate copolymer, hydrogenated styrene block copolymer, high impact polystyrene (HIPS), general purpose polystyrene resin (GPPS), etc. Among them, styrene-butadiene copolymer (SB) is preferred from the viewpoint of the balance of various performances.

[0034] It is particularly preferable that the styrene resin contains a styrene elastomer, that is, a styrene resin that exhibits rubber elasticity at room temperature. When the sealant layer 3 contains a styrene elastomer, it is expected that the peel strength when, for example, the cover tape 10 is peeled off from the carrier tape is further improved.

[0035] When the sealant layer 3 contains a styrene-based resin, the ratio of the styrene-based resin in the sealant layer 3 is preferably 7.5 to 65 mass%, more preferably 8 to 63 mass%, and further preferably 15 to 62 mass%. According to the findings of the inventors, when a styrene-based resin is used, it is easy to achieve both inhibition of blocking and improvement of adhesive strength by appropriately adjusting the ratio.

[0036] Specific examples of (meth)acrylic resins include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and other acrylic acid esters; methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, and other methacrylic acid esters; and resins having structural units derived from monomers such as acrylonitrile, methacrylonitrile, and acrylamide. The (meth)acrylic resin may contain structural units derived from one or more monomers among these examples. Of course, the (meth)acrylic resin may further contain structural units derived from monomers other than these examples.

[0037] When the sealant layer 3 contains a (meth)acrylic resin, the ratio of the (meth)acrylic resin in the sealant layer 3 is preferably 5 to 63 mass%, more preferably 7 to 62 mass%, and even more preferably 8 to 55 mass%. According to the findings of the present inventors, when a (meth)acrylic resin is used, it is easy to achieve both inhibition of blocking and improvement of adhesive strength by appropriately adjusting the ratio.

[0038] The ester resin usually comprises a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component. Specific examples of the alcohol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, and other chain or branched aliphatic diols, alicyclic diols such as hydrogenated bisphenol A [2,2-bis(4-hydroxycyclohexyl)propane] and hydrogenated bisphenol A with alkylene oxide (average molar addition number of 2 to 12) having 2 to 4 carbon atoms, and trihydric or higher polyhydric alcohols such as glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These alcohol components may be used alone or in combination. Specific examples of the carboxylic acid component include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, azelaic acid, dodecylsuccinic acid, dodecenylsuccinic acid, and octenylsuccinic acid, polyvalent carboxylic acids having three or more valences such as trimellitic acid or its anhydride, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic aromatic dicarboxylic acid. These carboxylic acid components may be used alone or in combination.

[0039] Incidentally, when the sealant layer 3 contains both a styrene-based resin and a (meth)acrylic resin, from the viewpoint of optimizing various performances, the ratio (styrene-based resin / (meth)acrylic resin) is preferably 0.1 to 10, more preferably 0.12 to 8.5, even more preferably 0.15 to 7, and particularly preferably 0.5 to 7, in terms of mass ratio.

[0040] The sealant layer 3 contains a conductive polymer from the viewpoint of suppressing the generation and charging of static electricity by making the sealant layer 3 conductive. Specifically, the sealant layer 3 is made of a mixture of a thermoplastic resin, such as a styrene-based resin or a (meth)acrylic resin, and a conductive polymer.

[0041] As the conductive polymer, π-conjugated conductive polymers are preferred in terms of good conductivity and availability.Specific conductive polymers include polypyrroles, polythiophenes, polyacetylenes, polyphenylenes, polyphenylenevinylenes, polyanilines, polyacenes, polythiophenevinylenes, and copolymers thereof.In terms of stability in air, polypyrroles, polythiophenes, and polyanilines are preferred.

[0042] Specific examples of π-conjugated conductive polymers include polypyrrole, poly(N-methylpyrrole), poly(3-methylpyrrole), poly(3-ethylpyrrole), poly(3-n-propylpyrrole), poly(3-butylpyrrole), poly(3-octylpyrrole), poly(3-decylpyrrole), poly(3-dodecylpyrrole), poly(3,4-dimethylpyrrole), poly(3,4-dibutylpyrrole), poly(3-carboxypyrrole), and poly(3-methyl-4-carboxypyrrole). pyrrole), poly(3-methyl-4-carboxyethylpyrrole), poly(3-methyl-4-carboxybutylpyrrole), poly(3-hydroxypyrrole), poly(3-methoxypyrrole), poly(3-ethoxypyrrole), poly(3-butoxypyrrole), poly(3-methyl-4-hexyloxypyrrole), poly(thiophene), poly(3-methylthiophene), poly(3-ethylthiophene), poly(3-propylthiophene), poly(3-butylthiophene), poly(3-hexylthiophene), poly(3-heptylthiophene), poly(3-octylthiophene), poly(3-decylthiophene), poly(3-dodecylthiophene), poly(3-octadecylthiophene), poly(3-bromothiophene), poly(3-chlorothiophene), poly(3-iodothiophene), poly(3-cyanothiophene), poly(3-phenylthiophene), poly(3,4-dimethylthiophene), poly(3,4-dibutylthiophene), poly(3-hydroxythiophene), poly(3-methoxythiophene), poly(3-ethoxythiophene), poly(3-butoxythiophene), poly(3-hexyloxythiophene), poly(3-heptyloxythiophene), poly(3-octyloxythiophene), poly(3-decyloxythiophene), poly(3-dodecyloxythiophene), poly(3-octadecyloxythiophene), poly(3-methyl-4-methoxythiophene), poly(3,4-ethylenedioxythiophene), poly(3-methyl-4-ethoxythiophene), poly(3-carboxythiophene), poly(3-methyl-4-carboxythiophene), poly(3-methyl-4-carboxyethylthiophene), poly(3-methyl-4-carboxybutylthiophene), polyaniline, poly(2-methylaniline), poly(3-isobutylaniline), poly(2-anilinesulfonic acid), poly(3-anilinesulfonic acid), etc.

[0043] The sealant layer 3 may contain a dopant for enhancing the conductivity of the conductive polymer in addition to the conductive polymer. A preferred example of the dopant is a polymer having an anionic functional group. Specific examples of polymers having anionic functional groups include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacryl sulfonic acid, polymethacryl sulfonic acid, poly(2-acrylamido-2-methylpropane sulfonic acid), polyisoprene sulfonic acid, polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacryl carboxylic acid, polymethacryl carboxylic acid, poly(2-acrylamido-2-methylpropane carboxylic acid), polyisoprene carboxylic acid, polyacrylic acid, etc. Among these, polystyrene sulfonic acid, polyacryl sulfonic acid, and polymethacryl sulfonic acid are preferred, and polystyrene sulfonic acid is particularly preferred.

[0044] Among conductive polymers, polythiophenes, i.e., conductive polymers containing a structure derived from thiophene or a thiophene derivative, are preferred from the viewpoints of good electrical conductivity and heat resistance during heat sealing. As polythiophenes, poly(3,4-ethylenedioxythiophene) is particularly preferred from the viewpoints of maintaining and improving various performances.

[0045] In selecting a conductive polymer, it is preferable to take into consideration its solubility and dispersibility in organic solvents. As the conductive polymer, it is preferable to select a conductive polymer that is soluble or dispersible in an organic solvent. Incidentally, the conductive polymer being soluble in an organic solvent means, for example, that the conductive polymer is dissolved in the coating liquid for forming a sealant layer described below and no undissolved portion remains. In addition, the conductive polymer being dispersible in an organic solvent means that the conductive polymer can be made to float in the organic solvent as fine particles and can be made to be in a state where it does not substantially precipitate. When dispersing the conductive polymer in an organic solvent, any dispersant may be used.

[0046] From the viewpoints of ease of preparation of a solution for forming the sealant layer 3 and of eliminating disadvantages due to aggregation of the conductive polymer, it is preferable that the conductive polymer be soluble in an organic solvent. Conductive polymers that are soluble in organic solvents can be said to be lipophilic, or hydrophobic. The sealant layer 3 containing hydrophobic conductive polymers is considered to be less prone to moisture absorption even in high temperature and high humidity environments. It is expected that the resistance to moisture absorption will make the sealant layer even less prone to blocking, even in high humidity conditions. Conductive polymers soluble in organic solvents are commercially available from, for example, Matsuo Sangyo Co., Ltd.

[0047] Incidentally, poly(3,4-ethylenedioxythiophene):polystyrenesulfonic acid complex (so-called PEDOT / PSS) is sometimes used in conventional cover tapes. However, most conventional PEDOT / PSS is supplied as an aqueous dispersion (Reference: Chemistry and Education, Vol. 67, No. 2 (2019), pp. 86-89), and is not intended to be dissolved in an organic solvent for use.

[0048] The ratio of the conductive polymer in the sealant layer 3 is, for example, 1 to 50 mass %, preferably 2 to 45 mass %.

[0049] The sealant layer 3 may contain other components such as a leveling agent and a conductive assistant.

[0050] The exposed surface of the sealant layer 3 has an Spd of 400,000 to 1,500,000 / mm 2 It is sufficient that Sdq is 0.05 to 0.3, but by satisfying other characteristics, blocking can be further reduced and other performances can be improved in some cases. For example, the arithmetic mean height Sa of the exposed surface of the sealant layer 3 as defined by ISO 25178 is preferably 0.05 to 0.5 μm, more preferably 0.06 to 0.45 μm, and even more preferably 0.07 to 0.40 μm. When Sa is within the range of values ​​shown here, various performances can be further improved in some cases.

[0051] As described above, in this embodiment, blocking can be suppressed without including a particulate antiblocking agent in the sealant layer 3. In this embodiment, the use of an antiblocking agent is not excluded. However, the use of an antiblocking agent requires additional costs, and there is also a concern that the inclusion of an antiblocking agent in the sealant layer 3 may reduce the adhesive strength (peel strength) of the cover tape 10 to the carrier tape or reduce the transparency of the cover tape 10. Considering all factors, it is preferable that the sealant layer 3 does not contain inorganic particles such as antiblocking agents, or if it does contain inorganic particles, the amount of such particles is 1% by mass or less of the entire sealant layer 3.

[0052] The thickness of the sealant layer 3 is preferably 0.03 to 20 μm, and more preferably 0.03 to 15 μm, from the viewpoints of shortening the heat sealing operation time and obtaining strong sealing strength.

[0053] [Other layers] The cover tape 10 may or may not include additional layers different from the base layer 1 , the intermediate layer 2 and the sealant layer 3 . For example, an anchor coat layer for enhancing adhesion may be provided between the base layer 1 and the intermediate layer 2 (the anchor coat layer is not shown in FIG. 1).

[0054] [Total thickness] From the viewpoint of a balance between ensuring strength and ease of handling, the total thickness of the cover tape 10 is preferably 40 to 65 μm, and more preferably 45 to 60 μm.

[0055] <Cover tape manufacturing method> The cover tape 10 can be manufactured by using appropriate materials and a suitable manufacturing process. A suitable manufacturing method and materials used in the manufacturing method will be described below.

[0056] First, a laminate is obtained by forming an intermediate layer 2 on the surface of a base layer 1. The base layer 1 is preferably a film formed of a polyester resin, a polyolefin resin, etc. The intermediate layer 2 can be formed by, for example, an extrusion lamination method or a dry lamination method. In order to prevent peeling between the base layer 1 and the intermediate layer 2, a layer of, for example, an anchor coating agent may be present between the base layer 1 and the intermediate layer 2.

[0057] Next, a coating liquid for forming a sealant layer is applied to the surface of the intermediate layer 2 opposite to the substrate layer 1, and then dried. As a coating method, for example, a gravure coating method can be used. The coating liquid for forming the sealant layer can typically be obtained by thoroughly mixing a resin (preferably a thermoplastic resin such as the above-mentioned styrene-based resin or (meth)acrylic-based resin), a conductive polymer, and a solvent capable of dissolving or dispersing these.

[0058] In the present embodiment, it is particularly preferable that after forming the intermediate layer 2 on the surface of the base layer 1 to obtain a laminate, the laminate is aged for a certain period of time, and then the coating liquid for forming a sealant layer is applied to the surface of the intermediate layer 2. The aging time is, for example, 12 to 48 hours, and preferably 18 to 36 hours. The temperature during aging is, for example, 10 to 40°C, and preferably 20 to 30°C. The humidity during aging is, for example, 30 to 70% RH, and preferably 40 to 60% RH.

[0059] Although the detailed mechanism is unclear, it is thought that by allowing the laminate on which the intermediate layer 2 is formed to stand for a certain period of time, the surface of the intermediate layer 2 dries appropriately, or some of the components contained in the intermediate layer 2 bleed out to the surface. By providing the sealant layer 3 by applying a sealant layer-forming coating liquid to the surface of the intermediate layer 2 in such a surface state, fine irregularities are generated on the exposed surface of the sealant layer 3 after the solvent in the coating liquid has dried, and the Spd of the exposed surface of the sealant layer 3 is 400,000 to 1,500,000 / mm 2 It is estimated that Sdq is controlled to 0.05 to 0.3.

[0060] <Electronic component packaging> An electronic component package can be obtained from the above-described cover tape 10 and a carrier tape having electronic components housed in recesses. This will be described with reference to FIG.

[0061] In FIG. 2, cover tape 10 for packaging electronic components is used as a lid material for band-shaped carrier tape 20 having recessed pockets 21 continuously formed to match the shapes of electronic components. Specifically, the cover tape 10 for packaging electronic components is adhered (usually by heat sealing) to the surface of the carrier tape 20 so as to cover the entire opening of the pocket 21 of the carrier tape 20. Hereinafter, the structure obtained by adhering the cover tape 10 for packaging electronic components and the carrier tape 20 together will be referred to as the electronic component package 100.

[0062] The electronic component packaging body 100 can be produced, for example, by the following procedure. First, electronic components are placed in the pockets 21 of the carrier tape 20 . Next, the cover tape 10 for packaging electronic components is adhered to the surface of the carrier tape 20 by a heat sealing method so as to cover the entire opening of the pocket 21 of the carrier tape 20. At this time, the sealant layer 3 of the cover tape 10 for packaging electronic components is in contact with the carrier tape 20 (that is, the heat sealing is performed so that the "back surface" of the cover tape 10 for packaging electronic components in FIG. 2 becomes the sealant layer 3). The specific method and conditions for heat sealing are not particularly limited as long as the cover tape 10 for packaging electronic components is sufficiently strongly adhered to the carrier tape 20. Typically, a known heat sealing machine is used, and the heat sealing can be performed at a temperature of 100 to 240° C., a load of 0.1 to 10 kgf, and a time of 0.0001 to 1 second.

[0063] In this manner, a structure (electronic component packaging body 100) in which electronic components are hermetically housed is obtained. This structure (electronic component packaging 100) is, for example, wound on a reel and stored until the electronic components are to be used. Alternatively, the reel on which electronic component packaging 100 is wound may be transported to a remote location by sea or air. The reel may be made of metal, paper, plastic, or the like.

[0064] When the electronic components are to be used, the cover tape 10 for packaging electronic components is peeled off from the carrier tape 20, and the housed electronic components are taken out. There are no particular limitations on the electronic components contained in the electronic component packaging 100. Examples include general components used in the manufacture of electric and electronic devices, such as semiconductor chips, transistors, diodes, capacitors, piezoelectric elements, optical elements, LED-related members, connectors, and electrodes.

[0065] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of the present invention are included in the present invention. EXAMPLES

[0066] The embodiments of the present invention will be described in detail based on Examples and Comparative Examples. It should be noted that the present invention is not limited to the Examples. In the following, exponential notation may be indicated by the symbol "E." For example, 1.3E-06 is 1.3 x 10 -6 means.

[0067] <Production of cover tape (Examples 1 to 7)> An anchor coating agent was applied to an antistatic polyethylene terephthalate (PET) film having a thickness of 12 μm ("E7455" manufactured by Toyobo Co., Ltd.) by gravure coating to a wet thickness of 4 μm, and then dried at 100°C. Thereafter, low-density polyethylene (LDPE, "Sumikathene L705" manufactured by Sumitomo Chemical Co., Ltd.) was extrusion laminated and cooled with a cooling roll (surface temperature 20°C) to provide a 37 μm-thick intermediate layer. In this manner, a laminated film consisting of the base layer and the intermediate layer was produced.

[0068] The obtained laminated film was left to stand for 24 hours in an environment of 25° C. and 50% RH.

[0069] Then, a coating solution for forming a sealant layer (non-volatile component concentration adjusted to 12.5% ​​by mass) prepared by thoroughly dissolving or dispersing the materials shown in the "Sealant layer composition" column in Table 1 in methyl ethyl ketone was applied onto the intermediate layer side of the laminated film by gravure coating, and a dry film (sealant layer) with a thickness of 0.5 μm was formed. Details of each component in the composition of the sealant layer in Table 1 are as follows. Resin 1: (Meth)acrylic resin, DIC "A450A" Resin 2: Styrene-based resin (hydrogenated styrene-based thermoplastic elastomer, SEBS, Asahi Kasei Corporation "H1043") Conductive polymer 1: Polythiophene resin "CPA-24" manufactured by Matsuo Sangyo Co., Ltd. (soluble in methyl ethyl ketone)

[0070] The resulting three-layered film was cut to a width of 5.5 mm to prepare a cover tape.

[0071] <Production of Cover Tape (Comparative Examples 1 to 4)> A cover tape was obtained in the same manner as in Examples 1 to 7, except that the sealant layer-forming coating liquid was applied without waiting 24 hours (within 30 minutes) after preparing a laminated film consisting of a base layer and an intermediate layer, and the composition of the sealant layer-forming coating liquid was a sealant layer-forming coating liquid (non-volatile component concentration adjusted to 12.5 mass %) in which the materials shown in the "Sealant layer composition" column in Table 1 were sufficiently dissolved or dispersed in methyl ethyl ketone.

[0072] <Measurement of the properties of the exposed surface of the sealant layer> The following indices of the sealant layer (exposed) of each of the above-mentioned Examples and Comparative Examples were measured using a laser microscope VK-X3000 manufactured by Keyence Corp. The analysis software used was that attached to the device. Arithmetic mean height Sa as defined in ISO 25178 Peak density Spd as defined in ISO 25178 · Root mean square slope Sdq as defined in ISO 25178

[0073] <Blocking evaluation> First, the cover tape was wound tightly around a reel, and then it was left in a 60°C environment for 24 hours. After leaving the cover tape, the reel with the cover tape wound on it was turned vertically and slowly rotated in the opposite direction to the direction in which the cover tape was wound. If the wound cover tape could be unwound under its own weight, blocking was evaluated as "not occurring." If the wound cover tape could not be unwound under its own weight and it was necessary to pull the cover tape by hand to unwind it, blocking was evaluated as "occurring."

[0074] <Evaluation of adhesive strength (bonding strength)> The sealant layer side of the cover tape was joined to the uneven surface side of a polystyrene film ("CEL-E980A" manufactured by Sumitomo Bakelite Co., Ltd.) measuring 8 mm in width and having an average surface roughness (Ra) of 0.25 μm on the uneven surface side to obtain a laminate. This laminate was heat sealed using a two-blade iron with a blade of 0.4 mm wide and 28 mm long under the conditions of a sealing temperature of 180°C, a load of 5 kgf, a sealing time of 60 milliseconds, a carrier tape feed pitch of 4 mm, and 2 rows and 7 strikes using a heat sealer (Tokyo Wells Co., Ltd., "TWA-6621") to obtain sample A. Using the obtained sample A, the peel strength (N) immediately after heat sealing of the cover tape to the polystyrene film was measured while referring to the description of JIS C0806-3. Specifically, the peeling was performed using a peel tester (EPI's "PTS-5000") at 25°C, a peeling speed of 300 mm / min, and a peeling angle of 170°, and the peel strength was continuously recorded. Then, from the relationship between the recorded time and the peel strength, the average value of the peel strength for 10 seconds immediately after the start of peeling was calculated. This average value was adopted as the peel strength. Incidentally, the surface roughness (Ra) of the polystyrene film was measured on the part of the polystyrene film that was to be joined to the cover tape, using a surface roughness measuring device (Mitutoyo's "SJ-210") in accordance with JIS B 0601 (2001) before bonding to the cover tape.

[0075] <Surface resistance value of sealant layer side> The surface resistance (Ω / □) of the sealant layer of the resulting cover tape was measured at 25° C. and 50% RH using a surface resistance measuring device manufactured by SIMCO (ST-3 manufactured by SIMCO). The measurement was performed before and after the above-mentioned <Blocking Evaluation>.

[0076] Various information is summarized in Table 1.

[0077] [Table 1]

[0078] As shown in Table 1, in Examples 1 to 7, the Spd of the exposed surface of the sealant layer was 400,000 to 1,500,000 / mm 2In an evaluation using a cover tape with an Sdq of 0.05 to 0.3, blocking was unlikely to occur and the tape could be bonded to the carrier tape with appropriate adhesive strength (peel strength), even though the sealant layer contained a conductive polymer and no particulate anti-blocking agent was used.

[0079] In contrast, in Comparative Examples 1 to 3 in which Spd was less than 400,000, and in the evaluation using cover tapes in which Sdq was 0.04, less than 0.05, blocking occurred and the wound cover tape could not be unwound under its own weight.

[0080] Incidentally, the change in surface resistance value before and after the blocking evaluation was significant in Comparative Examples 1 to 4 compared to Examples 1 to 7. This is presumably because, in Comparative Examples 1 to 4, blocking caused the sealant layer to change in quality, or at least a part of the sealant layer to peel off or fall off when the cover tape was unwound from the reel.

[0081] Looking at Examples 1 to 7 in more detail, it can be seen that a relatively high ratio of the styrene-based resin in the sealant layer tends to further increase the peel strength (adhesive strength) while suppressing blocking. [Explanation of symbols]

[0082] 1 Base material layer 2. Middle Tier 3 Sealant Layer 10 Cover Tape 20 Carrier Tape 21 Pocket 100 Electronic component packaging body

Claims

1. A cover tape for packaging electronic components, comprising a base layer and a sealant layer provided on at least one side of the base layer, The sealant layer includes a conductive polymer, The surface of the sealant layer opposite to the base material layer is an exposed surface, The exposed surface has a peak density Spd of 400,000 to 1,500,000 / mm as defined by ISO 25178. ２ and The cover tape has a root mean square slope Sdq, as defined by ISO 25178, of 0.05 to 0.3 on the exposed surface.

2. 2. The cover tape of claim 1, The cover tape, wherein the conductive polymer comprises a polythiophene.

3. 3. The cover tape according to claim 1 or 2, The cover tape, wherein the conductive polymer is soluble or dispersible in an organic solvent.

4. 3. The cover tape according to claim 1 or 2, The cover tape, wherein the sealant layer comprises a styrene-based resin.

5. 3. The cover tape according to claim 1 or 2, The cover tape, wherein the sealant layer comprises a styrene-based elastomer.

6. 3. The cover tape according to claim 1 or 2, The cover tape further comprises an intermediate layer between the base layer and the sealant layer.

7. 7. The cover tape according to claim 6, The cover tape, wherein the intermediate layer comprises a polyethylene-based resin.

8. 3. The cover tape according to claim 1 or 2, The cover tape, wherein the sealant layer does not contain inorganic particles or contains inorganic particles in an amount of 1% by mass or less of the entire sealant layer.

9. 3. The cover tape according to claim 1 or 2, The cover tape has an arithmetic mean height Sa of 0.05 to 0.5 μm as defined in ISO 25178 on the exposed surface.

10. A carrier tape having electronic components housed in recesses and the cover tape according to claim 1 or 2, An electronic component package in which the sealant layer is adhered to the carrier tape so as to seal the electronic component.

Images