Cover tape and electronic component packaging

Abstract

A cover tape comprises: a base layer containing polyethylene terephthalate; a sealant layer containing a styrene resin; and an intermediate layer provided between the base layer and the sealant layer. In the cover tape, an arithmetic mean height Sa of an exposed surface on the sealant layer side is 0.05 to 0.35 μm.

Description

Technical Field

[0001] The present invention relates to a cover tape and an electronic component package. More specifically, the present invention relates to a cover tape preferably used for packaging electronic components and an electronic component package using the cover tape. Background Art

[0002] Carrier tapes and cover tapes are commonly used when transporting and storing electronic components.

[0003] Specifically, electronic components (semiconductor chips, etc.) are placed in the electronic component storage recess formed in the carrier tape, and then the cover tape is heat-sealed to the upper surface of the carrier tape to seal the electronic components in. The carrier tape is then wound into a reel for transportation and storage.

[0004] As a prior art of cover tape, for example, Patent Document 1 describes a cover tape for transporting electronic components, wherein a heat-adhesive resin layer is provided on a support, and an antistatic layer is provided on the outside of the support or between the support and the heat-adhesive resin layer. The contact angle with water on the surface of the heat-adhesive resin layer of the cover tape is 0.5 to 95°, and the surface resistivity is 1.0×10 13 Ω / □ or less.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2003-266016 Summary of the invention

[0008] Problems to be solved by the invention

[0009] Usually, the cover tape is in a state of being wound on a reel before use.

[0010] According to the findings of the present inventors, in a conventional cover tape, blocking may occur in a wound state before use.

[0011] Furthermore, from the viewpoint of visibility of the packaged electronic components, it is preferred that the cover tape be sufficiently transparent. However, according to the findings of the present inventors, there is room for improvement in the transparency of conventional cover tapes.

[0012] In view of these problems of conventional cover tapes, the present inventors have conducted various studies with the purpose of providing a cover tape that is less likely to cause blocking in a wound state before use and has good transparency.

[0013] Technical solutions to problems

[0014] The present inventors have conducted studies and have completed the invention provided below, thereby solving the above-mentioned problems.

[0015] According to the present invention, there is provided a cover tape comprising: a base layer containing polyethylene terephthalate; a sealant layer containing a styrene resin; and an intermediate layer provided between the base layer and the sealant layer.

[0016] The arithmetic mean height Sa of the exposed surface on the sealant layer side is 0.05 to 0.35 μm.

[0017] Furthermore, according to the present invention, there is provided an electronic component package including a carrier tape in which electronic components are stored in a recessed portion and the cover tape.

[0018] The sealant layer is bonded to the carrier tape to seal the electronic component.

[0019] Effects of the Invention

[0020] According to the present invention, there is provided a cover tape which is less likely to cause blocking in a rolled-up state before use and has excellent transparency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a diagram showing an example of a state where the cover tape is bonded (heat-sealed) to the carrier tape. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0023] The drawings are for illustration purposes only. The shapes, dimensions and ratios of the components in the drawings do not necessarily correspond to the actual items.

[0024] In this specification, the term "substantially" means that a range including a tolerance in manufacturing, a variation in assembly, and the like is included unless otherwise specified.

[0025] In this specification, unless otherwise specified, the expression "X to Y" in the description of a numerical range means greater than or equal to X and less than or equal to Y. For example, "1 to 5 mass %" means "1 mass % or more and 5 mass % or less".

[0026] In the description of the group (atomic group) in this specification, the description without description of substitution or unsubstituted includes both the group without substitution and the group with substitution. For example, "alkyl" includes not only the alkyl group without substitution (unsubstituted alkyl group) but also the alkyl group with substitution (substituted alkyl group).

[0027] The expression "(meth)acrylic acid" in this specification represents a concept including both acrylic acid and methacrylic acid. The same applies to similar expressions such as "(meth)acrylate".

[0028] The arithmetic mean height Sa and the root mean square height Sq in this specification are based on ISO 25178 which stipulates "surface roughness".

[0029] <Cover tape>

[0030] The cover tape of the present embodiment includes: a base layer containing polyethylene terephthalate; a sealant layer containing a styrene-based resin; and an intermediate layer provided between the base layer and the sealant layer.

[0031] In the cover tape of the present embodiment, the arithmetic mean height Sa of the exposed surface on the sealant layer side is 0.05 to 0.35 μm.

[0032] It is estimated that in the cover tape of the present embodiment, since Sa on the sealant layer side containing a styrene-based resin is 0.05 to 0.35 μm, surface irregularities of a size that may affect the visibility of the electronic component are reduced, and good transparency can be obtained.

[0033] Furthermore, it is believed that by providing the surface irregularities with Sa of about 0.05 to 0.35 μm on the sealant layer side containing the styrene resin, the overlapping cover tapes on the base material layer side and the sealant layer side can "moderately slide" with each other. Furthermore, it is believed that the force that may cause blocking in the wound cover tape is moderately alleviated.

[0034] In the cover tape of this embodiment, the electronic component is not easily attached because the Sa of the sealant layer containing styrene resin is 0.05 to 0.35 μm. It is believed that the contact area between the cover tape and the electronic component is reduced by Sa of 0.05 to 0.35 μm, which can suppress the sticking.

[0035] In order to manufacture the cover tape having a sealant layer side Sa of 0.05 to 0.35 μm in the present embodiment, it is important to select an appropriate manufacturing method / manufacturing conditions in addition to the selection of materials. The details are described later. For example, when the sealant layer is provided by an extrusion lamination method, the sealant layer is pressed with a moderate pressure on a cooling roller having a moderate surface roughness, thereby enabling the sealant layer side Sa to be appropriately adjusted.

[0036] The cover tape of this embodiment will be described further.

[0037] (Base material layer)

[0038] The substrate layer is not particularly limited as long as it contains polyethylene terephthalate (also referred to as PET). In other words, the substrate layer is composed of a resin film containing PET. PET is preferred in terms of low cost and excellent mechanical strength.

[0039] The base layer may be a single-layer resin film containing PET, or may be a laminated film composed of a plurality of layers containing PET.

[0040] The method for producing the resin film containing PET is not particularly limited, and examples of the production method include film-forming methods such as extrusion, casting, T-die, cutting, and inflation.

[0041] The resin film containing PET may be stretched or unstretched. From the viewpoint of strength, it is preferably stretched in a uniaxial direction or a biaxial direction, and more preferably stretched in a biaxial direction.

[0042] The base material layer may contain additives for the purpose of improving or modifying processability, heat resistance, weather resistance, mechanical properties, dimensional stability, oxidation resistance, sliding properties, mold release properties, flame retardancy, mildew resistance, electrical properties, strength, etc.

[0043] Examples of additives include various plastic compounding agents or additives, modified resins, etc. Other examples of additives include plasticizers, lubricants, crosslinking agents, antioxidants, ultraviolet absorbers, light stabilizers, fillers, antistatic agents, antiblocking agents, and colorants (dyes, pigments, etc.).

[0044] When the base material layer contains an additive component, the amount thereof is generally about 0.001 to 10% by mass based on the entire base material layer.

[0045] Any surface treatment can be applied to one or both sides of the resin film containing PET constituting the substrate layer. As examples of surface treatment, corona discharge treatment, plasma treatment, ozone treatment, flame treatment, glow discharge treatment, preheat treatment, dust removal treatment, vapor deposition treatment, chemical treatment, alkali treatment, etc. can be cited. Through these treatments, the adhesion (bonding force) between the substrate layer and the intermediate layer sometimes becomes larger. As surface treatment, any formation of a primer coating agent layer, a primer layer, an anchor coating agent layer, an adhesive layer, a vapor deposition anchor coating agent layer, etc. can also be cited.

[0046] The thickness of the substrate layer is preferably 2.5 to 100 μm, more preferably 6 to 50 μm, and further preferably 12 to 25 μm. When the substrate layer is 2.5 μm or more, it is easy to fully ensure the rigidity or mechanical strength of the cover tape. When the substrate layer is 100 μm or less, it is easy to fully ensure heat conduction from the substrate layer to the sealant layer during heat sealing, resulting in a shortened heat sealing time.

[0047] Furthermore, the occurrence of blocking can be further suppressed by adjusting the surface roughness of the exposed surface on the substrate layer side. The occurrence of blocking can be further suppressed by setting Sa and the like of the exposed surface on the sealant layer side to appropriate values ​​and the surface roughness of the exposed surface on the substrate layer side to an appropriate value.

[0048] Furthermore, by adjusting the surface roughness of the exposed surface on the substrate layer side, the transparency can be further improved.

[0049] Specifically, the arithmetic mean height Sa of the exposed surface on the substrate layer side is preferably 0.01 to 0.2 μm, more preferably 0.02 to 0.17 μm, further preferably 0.03 to 0.15 μm, and particularly preferably 0.03 to 0.1 μm.

[0050] (Sealing agent layer)

[0051] The sealant layer is not particularly limited as long as it contains a styrene-based resin.

[0052] The styrene resin preferably contains a styrene elastomer. Although the details are not clear, it is believed that the appropriate elasticity of the styrene elastomer improves the adhesion between the cover tape and the carrier tape and further increases the heat seal strength.

[0053] Examples of the styrene-based elastomer include block copolymers of vinyl aromatic hydrocarbons and conjugated dienes or derivatives thereof.

[0054] Examples of block copolymers of vinyl aromatic hydrocarbons and conjugated dienes include block copolymers containing a vinyl aromatic hydrocarbon represented by styrene as a main body, and block copolymers containing a conjugated diene such as butadiene and isoprene as a main body (a block containing a vinyl aromatic hydrocarbon as a "main body" refers to a block containing 50% by mass or more of the vinyl aromatic hydrocarbon, and a block containing a conjugated diene as a "main body" refers to a block containing more than 50% by mass of the conjugated diene).

[0055] Examples of the derivatives thereof include derivatives obtained by hydrogenating at least a part of the double bonds of the block copolymers described above, and derivatives modified with maleic acid, amines, or imines.

[0056] The content of styrene in the styrene-based elastomer (styrene content) is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less.

[0057] From another viewpoint, the content of styrene in the styrene-based elastomer (styrene content) is preferably 10% by mass or more, more preferably 20% by mass or less, and further preferably 25% by mass or more.

[0058] In addition to the styrene resin, the sealant layer may contain other resins from the viewpoint of heat sealability. The other resins may be appropriately selected from known thermoplastic resins and may be sufficiently melted / softened under heat sealing conditions generally used in packaging electronic components.

[0059] Specifically, the sealant layer may contain an olefin resin as a resin other than the styrene resin. Typically, the olefin resin may be a resin having a structural unit derived from an α-olefin such as ethylene, propylene, or butene. As the olefin resin, polyethylene or an ethylene copolymer is preferred. When the olefin resin is a copolymer, the copolymerization method may be any one of random, alternating, block, and the like.

[0060] The olefin resin preferably has a structural unit derived from an α-olefin and other structural units. In other words, the olefin resin is preferably a copolymer of an α-olefin monomer and a monomer other than the α-olefin monomer. More preferably, the olefin resin contains a structural unit derived from ethylene.

[0061] The "other structural unit" is preferably a structural unit derived from any monomer selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid ester and vinyl carboxylate. Since these structural units have appropriate polarity, they are considered to be involved in the adjustment of sealing strength.

[0062] Specific examples of the (meth)acrylate include methyl (meth)acrylate and ethyl (meth)acrylate.

[0063] Specific examples of the vinyl carboxylate include vinyl acetate, vinyl propionate, vinyl butyrate, and the like.

[0064] Specific examples of olefin resins include ethylene-vinyl acetate copolymers (EVA), ethylene-(meth)acrylic acid copolymers (EAA, EMAA, etc.), ethylene-(meth)acrylate copolymers (EEA, EMMA, EGMA, etc.), etc. These are also preferred in terms of cost and availability.

[0065] The ratio of "other structural units" in the olefin-based resin is preferably 6 to 34% by mass, more preferably 8 to 30% by mass, and further preferably 10 to 25% by mass. By appropriately adjusting this ratio, appropriate heat-sealing properties can be easily obtained.

[0066] When the olefin resin is a commercial product, the ratio of the "other structural units" in the olefin resin can be, for example, the value recorded in the catalog provided by the manufacturer or seller. 13 The ratio is determined from the area (integrated value) of a graph obtained by spectral measurement such as C-NMR.

[0067] The ratio of the styrene resin to other resins (olefin resins and the like) in the sealant layer is preferably 40:60 to 99:1, more preferably 50:50 to 97:3 in terms of mass ratio.

[0068] In addition to styrene resin or other resins, the sealant layer may also contain any additives. Examples of additives include anti-blocking agents, antistatic agents, tackifiers, slip agents, lubricants, plasticizers, antioxidants, ultraviolet absorbers, colorants, surfactants, inorganic particles, organic particles, etc. The Sa of the exposed surface through the sealant layer side is 0.05 to 0.35 μm, and the sealant layer contains appropriate additives, which can further reduce the occurrence of adhesion.

[0069] As the antistatic agent, a known antistatic agent can be used. For example, the following can be mentioned.

[0070] Cationic antistatic agents having cationic functional groups such as quaternary ammonium salts, pyridinium salts, primary amino groups, secondary amino groups, and tertiary amino groups. Preferably, the cationic polymer antistatic agent has a quaternary ammonium salt in the side chain. As commercially available products, SAFTMER ST1000 and SAFTMER ST2000H manufactured by Mitsubishi Chemical Corporation, ASA-29CP and ASA-31CP manufactured by TAKAMATSU OIL & FAT CO., LTD., BONDEIP PA and BONDEIP PM (quaternary ammonium ethyl acrylate sulfate) manufactured by Konishi Co., Ltd., and SF antistatic coating agent M-2 manufactured by DIC Corporation, etc.

[0071] Polymers containing a polyether structure (for example, polyamide-based copolymers such as polyetheresteramide, block polymers of polyolefin and polyether, polymers composed of polyethylene ether and glycol, etc.), polymers containing carboxylate groups such as potassium ion polymers, copolymers containing quaternary ammonium salt groups, etc.

[0072] Metal fillers such as tin oxide, zinc oxide, and titanium oxide.

[0073] ·Thiophene-based conductive polymers such as polyethylene dioxythiophene / polystyrene sulfonic acid (PEDOT / PSS).

[0074] Examples of the tackifier include petroleum resins, rosin resins, terpene resins, styrene resins (resins different from the above-mentioned styrene resins), coumarone-indene resins, etc. Among them, petroleum resins and styrene resins (resins different from the above-mentioned styrene resins) are preferred from the viewpoints of difficulty in adhesion of electronic components, heat sealing properties to carriers, gas barrier properties, etc.

[0075] Examples of petroleum resin tackifiers include aliphatic petroleum resins, aromatic petroleum resins, aliphatic-aromatic copolymerized petroleum resins, etc. Commercially available products include hydrogenated petroleum resins from Arakawa Chemical Industries, Ltd., under the trade name "ARKON" series.

[0076] Examples of lubricants include various amides such as palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, oleyl palmitamide, stearyl palmitamide, methylene bisstearamide, methylene bisoleamide, ethylene bisoleamide, and ethylene biserucic acid amide; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; and hydrogenated castor oil. When the sealant layer contains a lubricant, processability, roll release, and film sliding properties in extrusion processing, etc. are improved.

[0077] When the sealant layer contains an additive component, the amount thereof can be appropriately adjusted within a range of, for example, 0.01 to 20% by mass of the entire sealant layer.

[0078] The thickness of the sealant layer is, for example, 1 to 40 μm, preferably 3 to 30 μm, more preferably 5 to 20 μm, and particularly preferably 5 to 10 μm.

[0079] When the thickness of the sealant layer is 1 μm or more, more sufficient sealing performance can be ensured.

[0080] When the thickness of the sealant layer is 40 μm or less, the rigidity of the cover tape does not become too high. Therefore, even when a torsional stress is applied to the carrier tape after sealing, the cover tape can easily follow the deformation of the carrier tape. Therefore, it is possible to suppress the cover tape from accidentally peeling off from the carrier tape. In addition, when the thickness of the sealant layer is 40 μm or less, there is also an advantage of suppressing the "seepage" of the molten resin during heat sealing.

[0081] The arithmetic mean height Sa of the exposed surface on the sealant layer side is supplemented.

[0082] As described above, the arithmetic mean height Sa of the exposed surface on the sealant layer side is 0.05 to 0.35 μm. This Sa is preferably 0.06 to 0.32 μm, and more preferably 0.07 to 0.3 μm. By adjusting Sa, a better blocking prevention effect or transparency improvement effect can be obtained.

[0083] Furthermore, the root mean square height Sq of the exposed surface on the sealant layer side is preferably 0.05 to 0.35 μm, more preferably 0.06 to 0.32 μm, and further preferably 0.07 to 0.3 μm. It is believed that in addition to designing Sa to an appropriate value, designing Sq to an appropriate value can obtain more sufficient transparency and can adjust the "sliding" between the cover tapes to the best value.

[0084] (Middle layer)

[0085] The intermediate layer is provided between the substrate layer and the sealant layer.

[0086] The intermediate layer may not necessarily be in contact with the substrate layer and the sealant layer. That is, there may be an additional layer between the substrate layer and the intermediate layer, or there may be an additional layer between the sealant layer and the intermediate layer. Of course, the intermediate layer may be in contact with the substrate layer and the sealant layer.

[0087] The presence of the intermediate layer can improve the cushioning properties, impact resistance, and the like of the cover tape.

[0088] Examples of the material forming the intermediate layer include olefin resins, styrene resins, cyclic olefin resins, etc. Among them, olefin resins are preferred from the viewpoint of improving the cushioning properties of the entire cover tape.

[0089] As olefin resins, polyethylene, polypropylene, etc. can be cited, and polyethylene is preferred. In particular, from the viewpoint of cushioning properties, low-density polyethylene (LDPE) or linear low-density polyethylene (L-LDPE) is more preferred. In addition, from the viewpoint of both cushioning properties and strength, high-density polyethylene (HDPE) is also preferred.

[0090] The intermediate layer may contain various additives. Examples of the additives include the additives mentioned for the sealant layer or the base material layer.

[0091] When an intermediate layer is provided, the thickness thereof is preferably 10 to 45 μm, more preferably 15 to 40 μm, from the viewpoint of improving the cushioning properties of the entire cover tape without excessively impairing other properties.

[0092] (Any other layer)

[0093] The cover tape of the present embodiment may include any layer other than the base material layer, the sealant layer, and the intermediate layer.

[0094] As an example, the adhesive layer may be present between the substrate layer and the sealant layer, and / or between the sealant layer and the intermediate layer. As a material for forming the adhesive layer, various known solvent-based or water-based adhesion coating agents can be used, for example. Regarding the adhesion coating agent, more specifically, adhesion coating agents such as isocyanate-based, polyurethane-based, polyester-based, polyethyleneimine-based, polybutadiene-based, polyolefin-based, and alkyl titanate-based can be cited.

[0095] As another example, some thin layers may be provided on the surface of the substrate layer on the opposite side of the intermediate layer and / or on the surface of the sealant layer on the opposite side of the intermediate layer. For example, a thin layer is provided for anti-adhesion countermeasures or antistatic countermeasures. In the case where the thin layer contains an antistatic agent, the thin layer can become an antistatic layer. As an antistatic agent that can be used, for example, the antistatic agent exemplified as the antistatic agent that can be contained in the sealant layer can be cited. As an antistatic agent, a cationic antistatic agent is preferably used, and a cationic polymer antistatic agent having a quaternary ammonium salt in the side chain is more preferably used (SAFTMER ST1000, SAFTMER ST-2000H, etc. manufactured by Mitsubishi Chemical Corporation). By using an appropriate antistatic agent to provide a thin layer, sufficient antistatic function can be obtained, and the arithmetic mean height Sa of the exposed surface on the sealant layer side can be easily adjusted to 0.05 to 0.35 μm.

[0096] From the viewpoint of anti-blocking measures, the thin layer preferably contains an anti-blocking agent. Preferred examples of the anti-blocking agent include inorganic particles such as silica and alumina. The median particle size (catalog value) of the anti-blocking agent may be, for example, 0.1 to 0.2 μm.

[0097] As another example, a thin transfer layer may be provided on the sealant layer. In this case, peeling occurs between the sealant layer and the transfer layer, and the thin transfer layer is transferred to the carrier tape as the adherend. When the transfer layer contains an antistatic agent, the transfer layer also serves as the antistatic layer.

[0098] There are three types of mechanisms when the cover tape is peeled off from the carrier tape: an interface peeling mechanism, a transfer peeling mechanism, and an agglutination breaking mechanism. The interface peeling mechanism refers to a mechanism for peeling off the sealing surface of the cover tape and the carrier tape. The transfer peeling mechanism refers to a mechanism in which the sealant layer itself is hardly destroyed when the cover tape is peeled off from the carrier tape, and the layer in contact with the carrier tape is "transferred" to the carrier tape (remaining on the carrier tape side). The agglutination breaking mechanism refers to a type of peeling by destroying other layers different from the sealant layer or the sealant itself. The "transfer layer" refers to a layer that is set on the sealant layer and is peeled off by the transfer peeling mechanism when the cover tape is peeled off from the carrier tape. The transfer layer can be set using, for example, a (meth) acrylic resin, specifically the "Dianal" (registered trademark) series of acrylic resins for coatings / inks manufactured by Mitsubishi Chemical Corporation.

[0099] The thickness of the thin layer is preferably about 0.01 to 3 μm from the viewpoint of not excessively inhibiting the function of the base layer or the sealant layer.

[0100] For the sake of caution, when a thin layer is provided on the surface of the sealant layer opposite to the intermediate layer and the thin layer becomes the outermost layer on one side of the cover tape, Sa or Sq of the outermost layer is measured.

[0101] Of course, there may be no thin layer. In this case, the surface of the substrate layer opposite to the intermediate layer and the surface of the sealant layer opposite to the intermediate layer become exposed surfaces. And, the surface roughness of these exposed surfaces is measured.

[0102] (Width and length of cover tape)

[0103] The width and length of the cover tape of the present embodiment can be appropriately set mainly depending on the width and length of the carrier tape to which the cover tape is to be bonded.

[0104] Typically, the cover tape has a width of about 1 to 100 mm and a length of about 100 to 30,000 m.

[0105] (Manufacturing method of cover tape)

[0106] The method for manufacturing the cover tape of the present embodiment is not particularly limited, and the cover tape can be manufactured, for example, according to the following steps. In particular, by appropriately performing the "pressing" in the following (2), it is easy to manufacture a cover tape having a Sa of 0.05 to 0.35 μm.

[0107] (1) An intermediate layer is provided on one side of a film serving as a substrate layer by extrusion lamination. The extrusion temperature may be appropriately adjusted depending on the material of the intermediate layer, and is, for example, about 150 to 350°C.

[0108] (2) A sealant layer is provided on the intermediate layer provided in (1) (exposed surface) by extrusion lamination (extrusion temperature of about 280° C.) In this case, the sealant layer is preferably pressed against a cooling roll having protrusions on the surface to provide irregularities on the surface of the sealant layer.

[0109] The maximum height Rz of the cooling roller is preferably 1.0 to 4.0 μm, more preferably 1.5 to 3.0 μm.

[0110] The pressing pressure is preferably 0.05 to 0.4 MPa, more preferably 0.1 to 0.3 MPa. The pressing can be performed by a silicone rubber touch roll or the like disposed opposite to the cooling roll.

[0111] The temperature of the sealant layer extruded when the cooling roll is pressed is preferably about 200 to 250° C. Furthermore, the temperature of the cooling roll and the touch roll is preferably adjusted (cooled) to about 15 to 25° C.

[0112] By using a styrene-based resin as the material of the sealant layer and appropriately selecting various production conditions when forming the sealant layer, a cover tape having an arithmetic mean height Sa of the exposed surface on the sealant layer side of 0.05 to 0.35 μm can be easily obtained.

[0113] (3) An antistatic layer is provided on the surface of the substrate layer on the side opposite to the side on which the intermediate layer is provided by a gravure coating method.

[0114] (4) The surface (exposed surface) of the sealant layer provided in (2) is subjected to corona treatment, and then an antistatic layer or an antistatic layer and transfer layer is provided on the corona treated surface by gravure coating.

[0115] Even when a thin layer (antistatic layer, transfer layer, etc.) is provided in addition to the sealant layer, if the thin layer is sufficiently thin, the irregularities provided on the sealant layer are reflected on the exposed surface of the thin layer.

[0116] <Electronic component packaging>

[0117] An electronic component package can be obtained from the cover tape and the carrier tape in which the electronic components are stored in the recessed portion. Figure 1 Provide explanation.

[0118] exist Figure 1 In the embodiment, the cover tape 10 is used as a cover material of a tape-shaped carrier tape 20 , and the tape-shaped carrier tape 20 is continuously provided with concave grooves 21 corresponding to the shape of the electronic component.

[0119] Specifically, cover tape 10 is bonded (usually heat-sealed) to the surface of carrier tape 20 so as to cover the entire opening of recessed groove 21 of carrier tape 20. Hereinafter, a structure obtained by bonding cover tape 10 and carrier tape 20 is referred to as electronic component package 100.

[0120] The electronic component package 100 can be produced, for example, through the following steps.

[0121] First, electronic components are housed in the grooves 21 of the carrier tape 20 .

[0122] Next, the cover tape 10 is bonded to the surface of the carrier tape 20 by heat sealing so as to cover the entire opening of the groove 21 of the carrier tape 20. At this time, the surface of the cover tape 10 on the sealant layer side is in contact with the carrier tape 20. Thus, a structure (electronic component package 100) in which electronic components are sealed and stored can be obtained.

[0123] The specific operation method and conditions of heat sealing are not particularly limited as long as the cover tape 10 and the carrier tape 20 are sufficiently firmly bonded. Typically, it can be performed using a known taping machine 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.

[0124] The material of the carrier tape 20 is not particularly limited as long as it can be bonded to the cover tape 10 by heat sealing. It is usually made of resin. As an example, the carrier tape 20 is made of a material containing polystyrene resin, a material containing polycarbonate resin, a material containing polyethylene terephthalate resin, etc.

[0125] The electronic component package 100 is wound around a reel, for example, and then conveyed to a work area where the electronic component is mounted on a circuit board, etc. The reel may be made of metal, paper, plastic, or the like.

[0126] After the electronic component package 100 is conveyed to the work area, the cover tape 10 is peeled off from the carrier tape 20 to take out the stored electronic components.

[0127] The electronic components housed in the electronic component package 100 are not particularly limited and may include all components used to manufacture electrical and electronic equipment, such as semiconductor chips, transistors, diodes, capacitors, piezoelectric elements, optical elements, LED-related components, connectors, electrodes, and the like.

[0128] <Another embodiment>

[0129] The cover tape of this embodiment can also be expressed as follows.

[0130] 1. A cover tape comprising: a base layer comprising polyethylene terephthalate; a sealant layer comprising a styrene resin; and an intermediate layer disposed between the base layer and the sealant layer,

[0131] In the exposed surface on the sealing agent layer side, the contact angle of diiodomethane is θ d , set the hexadecane contact angle to θ h When θ h / θ d The value is 0.25~0.55.

[0132] 2. The cover tape according to 1., wherein:

[0133] The base material layer is present on the outermost surface of the cover tape.

[0134] When the diiodomethane contact angle of the exposed surface on the substrate layer side is θ d ', the hexadecane contact angle of the exposed surface on the substrate layer side is θ h ′, θ h ′ / θ d The value of ′ is 0.10~0.50.

[0135] 3. The cover tape according to 1. or 2., wherein:

[0136] The θ d It is 28~65°.

[0137] 4. The cover tape according to any one of 1. to 3., wherein

[0138] The θ h 5~35°.

[0139] 5. The cover tape according to any one of 1. to 4., wherein

[0140] The sealant layer contains a styrene-based elastomer as the styrene-based resin.

[0141] 6. The cover tape according to any one of 1. to 5., wherein

[0142] The intermediate layer contains an olefin-based resin.

[0143] 7. An electronic component package comprising a carrier tape in which electronic components are stored in recesses, and the cover tape according to any one of 1. to 6.

[0144] The sealant layer is bonded to the carrier tape to seal the electronic component.

[0145] From one point of view, the cover tape is required to have low viscosity (less stickiness) so that electronic parts are not easily attached.

[0146] From another perspective, the cover tape is required to have good heat sealing properties. That is, it is preferred that the cover tape be appropriately melted by heat and sufficiently firmly bonded to the carrier tape.

[0147] However, according to the inventors' understanding, it is difficult to achieve both the difficulty of attaching electronic components and the heat sealability as the ease of bonding to the carrier tape. That is, conventional cover tapes have room for improvement in achieving both of these properties.

[0148] The above 1. to 7. are for solving such problems.

[0149] As a viewpoint for designing the cover tape, the inventors adopted the diiodomethane contact angle θ of the exposed surface on the sealant layer side (the surface in contact with the electronic component and bonded to the carrier tape): d and hexadecane contact angle θ h This is because it is believed that the difficulty of pasting electronic components (stickiness) or the adhesion to the carrier tape is related to the physical properties of the exposed surface such as hydrophilicity and hydrophobicity or surface free energy.

[0150] As a result of the research, the present inventors have found that in a cover tape having a base layer containing polyethylene terephthalate, a sealant layer containing a styrene-based resin, and an intermediate layer provided between the base layer and the sealant layer, θ h / θ d The value of is designed to be 0.25 to 0.55. Thus, it is possible to achieve both the difficulty of pasting the electronic component and the heat sealing property.

[0151] Although the details are not clear, it is believed that by making the exposed surface of the sealant layer side in a state where the contact angle of diiodomethane with medium polarity is relatively large (difficult to wet), and the contact angle of hexadecane with low polarity is relatively small (easy to wet), the interaction with electronic components made of high polarity materials such as metal oxides is reduced, and the interaction with carrier tapes made of low polarity materials such as polystyrene is increased. In addition, it is believed that both the difficulty of pasting electronic components and the heat sealing performance with the carrier tape are taken into account.

[0152] To make θ h / θ d For a cover tape having a value of 0.25 to 0.55, in addition to the selection of materials, it is also important to select an appropriate manufacturing method / manufacturing conditions. From the perspective of materials, it is preferred to select, for example, a specific antistatic agent or particle dispersion. Also, from the perspective of manufacturing conditions, when forming the sealant layer, it is preferred to press a cooling roller having a moderate surface roughness onto the sealant layer with a moderate pressure.

[0153] As a reference, it is previously explained that, according to the knowledge of the present inventors, it is actually difficult to manufacture θ h / θ d The value is less than 0.25 of the cover tape.

[0154] If θ h / θ d When the value of θ is 0.25 to 0.55, the effect of easy pasting of electronic components or good heat sealing with the carrier tape can be obtained. However, by appropriately adjusting θ d or θ h The value itself, or θ h / θ d The value can balance the peel strength and anti-blocking properties (preventing the cover tapes from sticking to each other).

[0155] When considering the actual design point of view, θ d It is preferably 28 to 65°, more preferably 28 to 64°, and still more preferably 30 to 63°. h It is preferably 5 to 35°, and more preferably 7 to 33°. h / θ d The value of is preferably 0.25 to 0.53.

[0156] In addition to appropriately designing the θ of the exposed surface on the sealant layer side h / θ d In addition to the values ​​of, it is preferred to appropriately design various contact angles of the exposed surface on the substrate layer side. Thus, for example, when the cover tape is wound, there is an advantage of being able to ensure the anti-blocking property of the sealant layer side-substrate layer side.

[0157] Specifically, when the diiodomethane contact angle of the exposed surface on the substrate layer side is θ d ', the hexadecane contact angle of the exposed surface on the substrate layer side is θ h ′, preferably θ h ′ / θ d The value of ' is 0.10 to 0.50, and more preferably 0.12 to 0.48.

[0158] θ h The value of ' is preferably 3 to 30°, more preferably 5 to 28°.

[0159] θ d The value of ' is preferably 35 to 62°, more preferably 35 to 61°, further preferably 37 to 59°, and particularly preferably 37 to 60°.

[0160] In the cover tape of another embodiment, the constituent components, materials, thicknesses, etc. of the base layer, sealant layer, intermediate layer, and other optional layers (such as thin layers) are the same as those described in the above section <Cover tape>.

[0161] In the cover tape of another embodiment, the width or length of the cover tape is also the same as described in the above section <Cover tape>.

[0162] A method for manufacturing a cover tape according to another embodiment is substantially the same as the method described in the above (method for manufacturing a cover tape), but will be described again.

[0163] The cover tape according to another embodiment can preferably be manufactured through the following steps (1) to (4).

[0164] (1) An intermediate layer is provided on one side of a PET film constituting a substrate layer by extrusion lamination. The extrusion temperature can be set to about 300°C.

[0165] (2) A sealant layer is provided on the exposed surface of the provided intermediate layer by extrusion lamination. The extrusion temperature can be set at about 280°C.

[0166] At this time, it is preferred that the sealant layer before curing is pressed against a cooling roller having protrusions with a surface roughness (maximum height Rz) of about 1 to 2 μm. The pressure at this time is preferably 0.05 to 0.4 MPa, more preferably 0.1 to 0.3 MPa. The pressure can preferably be adjusted by pressing a silicone rubber contact roller from the substrate layer side. In this way, it is easy to obtain a surface property that is adjusted and θ h / θ d The value of the cover tape is 0.25 to 0.55.

[0167] Furthermore, as shown in (4) below, even if an antistatic layer or an antistatic layer / transfer layer is further provided on the exposed surface of the sealant layer, as long as they are sufficiently thin, the surface properties of the sealant layer will be reflected on the antistatic layer or the antistatic layer / transfer layer. h / θ d The value of the cover tape is 0.25 to 0.55.

[0168] (3) An antistatic layer is provided on the surface of the substrate layer opposite to the surface on which the intermediate layer is provided. The antistatic layer is preferably provided by applying a coating liquid by gravure coating.

[0169] (4) The exposed surface of the sealant layer provided in (2) is subjected to a corona treatment, and then an antistatic layer or an antistatic layer and transfer layer is provided on the corona treated surface by a coating method.

[0170] The embodiments of the present invention are described above, but these are only examples of the present invention, and various structures other than the above can be adopted. In addition, the present invention is not limited to the above embodiments, and modifications and improvements within the scope of achieving the purpose of the present invention are included in the present invention.

[0171] [Example]

[0172] Embodiments of the present invention will be described in detail based on Examples and Comparative Examples. However, for the sake of caution, it is to be noted that the present invention is not limited to the Examples.

[0173] First, an example of a cover tape in which the arithmetic mean height Sa of the exposed surface on the sealant layer side is 0.05 to 0.35 μm will be described below.

[0174] <Material preparation>

[0175] Prepare the following materials.

[0176] (Resin (for forming an intermediate layer / sealant layer by extrusion lamination))

[0177] H1041: Styrene resin, manufactured by Asahi Kasei Corporation, trade name "Tuftec H1041"

[0178] H1043: Styrene resin, manufactured by Asahi Kasei Corporation, trade name "Tuftec H1043"

[0179] KF260T: Polyolefin resin, linear low-density polyethylene, manufactured by Japan Polyethylene Corporation, trade name "KERNEL KF260T"

[0180] AC1820: polyolefin resin, ethylene-methyl acrylate copolymer, manufactured by DOW-MITSUI POLYCHEMICALS CO., LTD., trade name "Elvaloy AC1820"

[0181] (Material for forming an antistatic layer or an antistatic layer and transfer layer)

[0182] · SAFTMER ST-1000: Cationic polymer antistatic agent, manufactured by Mitsubishi Chemical Corporation, trade name "SAFTMER ST-1000"

[0183] · SAFTMER ST-2000H: Cationic polymer antistatic agent (manufactured by Mitsubishi Chemical Corporation, trade name "SAFTMER ST-2000H"

[0184] ·SNS-10T: Conductive filler, antimony-doped tin oxide solution, manufactured by ISHIHARA SANGYOKAISHA, LTD., trade name "SNS-10T"

[0185] BR-113: Acrylic resin, manufactured by Mitsubishi Chemical Corporation, trade name "Dianal BR-113"

[0186] <Manufacturing of cover tape>

[0187] (summary)

[0188] The cover tapes of the examples and comparative examples were manufactured roughly according to the following procedures. As the raw materials constituting each layer, the raw materials listed in Table 1 were used.

[0189] (1) An intermediate layer is provided on one surface of a polyester film constituting a base layer by an extrusion lamination method (extrusion temperature of about 300° C.).

[0190] (2) A sealant layer was provided on the provided intermediate layer (exposed surface) by extrusion lamination (extrusion temperature of about 280° C.) At this time, the sealant layer was pressed against a cooling roll having protrusions on the surface to adjust the surface roughness.

[0191] (3) An antistatic layer is provided on the surface of the substrate layer on the side opposite to the side on which the intermediate layer is provided by a coating method.

[0192] (4) The surface (exposed surface) of the sealant layer provided in (2) is subjected to a corona treatment, and then an antistatic layer or an antistatic layer and transfer layer is provided on the corona treated surface by a coating method.

[0193] In Example 2, (3) and (4) were not performed. Therefore, the cover tape of Example 2 does not include an antistatic layer, nor does it include an antistatic layer and transfer layer.

[0194] The following describes the manufacturing method in more detail by taking the cover tape of Embodiment 4 as an example.

[0195] (Manufacturing of Cover Tape of Example 4)

[0196] On one side of a biaxially stretched polyester film (manufactured by TOYOBO CO., LTD., trade name E5102) having a film thickness of 16 μm as a substrate layer, a linear low-density polyethylene (manufactured by Japan Polyethylene Corporation, trade name "KERNEL KF260T") having a thickness of 20 μm was formed by extrusion lamination at an extrusion temperature of 300° C. Thus, an intermediate layer was provided.

[0197] On the formed intermediate layer, a styrene elastomer (manufactured by Asahi Kasei Corporation, trade name Tuftec H1043) was formed into a film with a thickness of 10 μm at an extrusion temperature of 280° C. by an extrusion lamination method. Thus, a sealant layer was formed. During the film formation, the sealant layer was pressed against a cooling roll having protrusions with a maximum height Rz of 1.5 μm, and a silicone rubber touch roll was pressed from the substrate layer side at a pressure of 0.3 MPa, thereby adjusting the surface roughness of the sealant layer.

[0198] In the above, the temperature of the cooling roll and the touch roll was adjusted (cooled) to about 20° C. Furthermore, the temperature of the sealant layer when the cooling roll and the touch roll were pressed was about 200 to 250° C.

[0199] Furthermore, an antistatic agent "SAFTMER ST-2000H" (manufactured by Mitsubishi Chemical Corporation) was applied to the surface of the substrate layer opposite to the surface provided with the intermediate layer using a gravure coater to a thickness of 0.1 μm after drying. Thus, an antistatic layer was provided.

[0200] Furthermore, the surface of the sealant layer formed above was subjected to corona treatment.

[0201] Then, a coating solution obtained by mixing acrylic resin "Dianal BR-113" (manufactured by Mitsubishi Chemical Corporation) and conductive filler solution "SNS-10T" (manufactured by ISHIHARA SANGYO KAISHA, LTD.) in a mass ratio of 1:4 was applied to the corona treated surface using a gravure coater to a thickness of 0.5 μm after drying. In this way, an antistatic layer and transfer layer was provided.

[0202] As described above, a cover tape including five layers in this order: an antistatic layer, a base material layer, an intermediate layer, a sealant layer, and an antistatic layer / transfer layer was obtained.

[0203] (Manufacturing of Cover Tapes of Examples 1 to 3 and Comparative Examples 1 and 2)

[0204] The materials listed in Table 1 were used as the materials, and a cover tape was produced in the same manner as in Example 4 except that the surface roughness of the sealant layer was adjusted by changing the surface roughness of the cooling roll and the touch roll pressure as follows.

[0205] Example 1: 1.5 μm, 0.1 MPa

[0206] Example 2: 2.5 μm, 0.2 MPa

[0207] Examples 3 and 4: 1.5 μm, 0.3 MPa

[0208] Comparative Example 1: 0.5 μm, 0.2 MPa

[0209] Comparative Example 2: 5.5 μm, 0.2 MPa

[0210] (Measurement of surface roughness)

[0211] For the cover tapes of the embodiments and comparative examples, the arithmetic mean height Sa1 and the root mean square height Sq on the exposed surface on the sealant layer side, and the arithmetic mean height Sa2 on the exposed surface on the base layer side were measured using an ultra-depth profile measurement microscope ("VK9700" manufactured by KEYENCE CORPORATION) in accordance with ISO25178.

[0212] <Performance Evaluation>

[0213] (Anti-blocking)

[0214] The cover tape of each embodiment and comparative example was cut into a width of 5.4 mm and a length of 500 m. Then, the cut cover tape was wound on a paper tube to obtain a roll. The roll was placed in an environment of 40°C for 24 hours. After being placed, the adhesion strength (degree of adhesion) of the front and back sides of the cover tape was evaluated based on whether the cover tape could be unwound by its own weight.

[0215] The wound product that could be unwound by its own weight was evaluated as "0" (good anti-blocking property), and the wound product that was tightly adhered and could not be unwound by its own weight was evaluated as "×" (poor anti-blocking property).

[0216] (Transparency)

[0217] Transparency was evaluated by measuring turbidity. Specifically, the turbidity of the cover tape of each example and comparative example was measured in accordance with JIS K 7105 (1998) Measurement Method A. It can be said that the smaller the turbidity value, the more transparent the cover tape.

[0218] (Adhesion resistance of electronic parts)

[0219] The cover tape was pasted on the slide glass with the exposed surface of the sealant layer facing upward. A test sample was prepared by placing 20 metal sheets (length: 0.4 mm × width: 0.8 mm × thickness: 0.4 mm) on the exposed surface. The metal sheets were made by cutting nickel with a precision cutting machine, processed into sheets with length: 0.4 mm × width: 0.8 mm × thickness: 0.4 mm, and provided with a surface oxide film.

[0220] The test sample was left at 60°C and 95% RH for 24 hours, and then at room temperature and humidity for 24 hours. Then, the test piece was vibrated at 25 Hz for 20 seconds while the slide was turned over. The attachment ratio (%) was calculated based on the number of metal pieces attached to the exposed surface. The smaller the value, the less likely the electronic components are to stick, and it can be said that it has the best performance as a cover tape.

[0221] Table 1 summarizes the formulations and thicknesses of the respective layers of the cover tape, and Table 2 summarizes the surface roughness measurement results and performance evaluation results.

[0222]

[0223] [Table 2]

[0224]

[0225] As shown in Table 2, in the evaluation of the cover tapes of Examples 1 to 4, the occurrence of blocking in the wound state was suppressed. In addition, the cover tapes of Examples 1 to 4 had good transparency. In addition, in the cover tapes of Examples 1 to 4, sticking of electronic components was suppressed.

[0226] On the other hand, in the evaluation of the cover tape of Comparative Example 1 in which Sa1 was less than 0.05 μm, the anti-blocking property was poor. In addition, in the evaluation of the cover tape of Comparative Example 2 in which Sa1 exceeded 0.35 μm, the transparency was poor.

[0227] Next, another embodiment is described with respect to θ h / θ d Examples and comparative examples of cover tapes having a value of 0.25 to 0.55.

[0228] <Material preparation>

[0229] Prepare the following materials.

[0230] (Resin (film for forming base layer))

[0231] E5102: Biaxially stretched film made mainly of polyethylene terephthalate (PET), manufactured by Toyobo Co., Ltd., Toyobo terephthalate (registered trademark) film, product name "E5102" (thickness is shown in the table below)

[0232] (Resin (for forming an intermediate layer / sealant layer by extrusion lamination))

[0233] H1041: Styrene-based elastomer, manufactured by Asahi Kasei Corporation, trade name "Tuftec H1041", styrene / butadiene·butylene ratio = 30 / 70 (mass ratio)

[0234] H1043: styrene-based elastomer, manufactured by Asahi Kasei Corporation, trade name "Tuftec H1043", styrene / butadiene·butylene ratio = 67 / 33 (mass ratio)

[0235] KF260T: Polyolefin resin, linear low-density polyethylene, manufactured by Japan Polyethylene Corporation, trade name "KERNEL KF260T"

[0236] AC1820: polyolefin resin, ethylene-methyl acrylate copolymer, manufactured by DOW-MITSUI POLYCHEMICALS CO., LTD., trade name "Elvaloy AC1820", ratio of structural units derived from methyl acrylate = 20 mass%

[0237] (Material for forming an antistatic layer or an antistatic layer and transfer layer)

[0238] · SAFTMER ST-1000: Cationic polymer antistatic agent, manufactured by Mitsubishi Chemical Corporation, trade name "SAFTMER ST-1000"

[0239] 2000H: Cationic polymer antistatic agent, manufactured by Mitsubishi Chemical Corporation, trade name "SAFTMER ST-2000H"

[0240] AERODISP W630: anti-blocking agent, a dispersion of alumina particles with a median particle size of 0.14 μm (alumina content 29-31%), manufactured by NIPPON AEROSIL CO., LTD.

[0241] ·SNS-10T: Conductive filler, antimony-doped tin oxide solution, manufactured by ISHIHARA SANGYOKAISHA, LTD., trade name "SNS-10T"

[0242] ·ASA-2030: Polyester antistatic agent, manufactured by TAKAMATSU OIL & FAT CO., LTD., trade name "ASA-2030"

[0243] BR-113: Acrylic resin, manufactured by Mitsubishi Chemical Corporation, trade name "Dianal BR-113"

[0244] <Manufacturing of cover tape>

[0245] The cover tapes of the examples and comparative examples were manufactured roughly according to the following procedures. As the raw materials constituting each layer, the raw materials listed in Table 3 were used.

[0246] (1) An intermediate layer is provided on one surface of a polyester film constituting a base layer by an extrusion lamination method (extrusion temperature of about 300° C.).

[0247] (2) A sealant layer was provided on the provided intermediate layer (exposed surface) by extrusion lamination (extrusion temperature of about 280°C).

[0248] (3) An antistatic layer is provided on the surface of the substrate layer on the side opposite to the side on which the intermediate layer is provided by a gravure coating method.

[0249] (4) The surface (exposed surface) of the sealant layer provided in (2) is subjected to a corona treatment, and then an antistatic layer or an antistatic layer and transfer layer is provided on the corona treated surface by a coating method.

[0250] In addition, (3) and (4) were not performed in Example 2'. Therefore, the cover tape of Example 2' does not include an antistatic layer, nor does it include an antistatic layer and transfer layer.

[0251] The following describes the manufacturing method in more detail by taking the cover tape of Embodiment 4' as an example.

[0252] (Manufacturing of Cover Tape of Example 4')

[0253] On one side of a biaxially stretched polyester film (manufactured by TOYOBO CO., LTD., trade name E5102) having a film thickness of 16 μm as a substrate layer, a linear low-density polyethylene (manufactured by Japan Polyethylene Corporation, trade name "KERNEL KF260T") having a thickness of 20 μm was formed by extrusion lamination at an extrusion temperature of 300° C. Thus, an intermediate layer was provided.

[0254] On the formed intermediate layer, a styrene elastomer (manufactured by Asahi Kasei Corporation, trade name Tuftec H1043) was formed into a film with a thickness of 10 μm at an extrusion temperature of 280° C. by an extrusion lamination method. Thus, a sealant layer was formed. During the film formation, the sealant layer was pressed against a cooling roll having protrusions with a maximum height Rz of 1.5 μm, and a silicone rubber touch roll was pressed from the substrate layer side at a pressure of 0.3 MPa. Thus, the surface properties of the sealant layer were adjusted.

[0255] Furthermore, an antistatic agent 2 "SAFTMER ST-2000H" (manufactured by Mitsubishi Chemical Corporation) was applied to the surface of the substrate layer opposite to the surface provided with the intermediate layer using a gravure coater to a thickness of 0.1 μm after drying. Thus, an antistatic layer was provided.

[0256] Furthermore, the surface of the sealant layer formed in the above was subjected to a corona treatment. Then, on the corona-treated surface, a coating solution obtained by mixing acrylic resin "Dianal BR-113" (manufactured by Mitsubishi Chemical Corporation) and conductive filler solution "SNS-10T" (manufactured by ISHIHARA SANGYO KAISHA, LTD.) in a mass ratio of 1:4 was applied using a gravure coater to a thickness of 0.5 μm after drying. Thus, an antistatic layer and transfer layer was provided.

[0257] As described above, a cover tape including five layers in this order: an antistatic layer, a base material layer, an intermediate layer, a sealant layer, and an antistatic layer / transfer layer was obtained.

[0258] (Manufacturing of Cover Tapes of Examples 1' to 3' and Comparative Example 1')

[0259] The materials listed in Table 3 were used as the materials, and a cover tape was produced in the same manner as in Example 4' except that the surface roughness of the sealant layer was adjusted and the maximum height Rz of the cooling roll and the touch roll pressure were changed as follows.

[0260] Example 1' and Comparative Example 1': 1.5 μm, 0.1 MPa

[0261] Example 2': 2.5 μm, 0.2 MPa

[0262] ·Examples 3' and 4': 1.5 μm, 0.3 MPa

[0263] <Measurement of contact angle>

[0264] 1 μL of diiodomethane or hexadecane was dropped onto both surfaces of the cover tape (the exposed surface of the sealant layer and the exposed surface of the base layer), and the contact angle was measured 1 second after the dropwise addition using a contact angle meter (DM-SA manufactured by Kyowa Interface Science Co., Ltd.).

[0265] <Evaluation of the difficulty of attaching electronic components>

[0266] First, the cover tape was attached to the slide glass with the exposed surface of the sealant layer facing upward. Then, a test sample was prepared by placing 20 metal sheets (length: 0.4 mm × width: 0.8 mm × thickness: 0.4 mm) on the exposed surface. The metal sheets were made by cutting nickel with a precision cutting machine, and processed into sheets with a length: 0.4 mm × width: 0.8 mm × thickness: 0.4 mm, and provided with a surface oxide film.

[0267] The test sample was left at 60°C and 95% RH for 24 hours, and then at room temperature and humidity for 24 hours. Then, the test piece was vibrated at 25 Hz for 20 seconds while the slide was turned over. The attachment ratio (%) was calculated based on the number of metal pieces attached to the exposed surface. The smaller the value, the less likely the electronic components are to stick, and it can be said that it has the best performance as a cover tape.

[0268] <Evaluation of heat sealability (measurement of peel strength)>

[0269] The cover tape was cut into a width of 5.3 mm and heat-sealed to the surface of the polystyrene carrier tape using a taping machine (Tokyo Weld Co., Ltd.: TWA-6621) at 170°C, 5 kgf, and 0.05 seconds. The peel strength immediately after heat sealing was measured.

[0270] The peel strength was measured using a peel tester at a peel speed of 300 mm / min and a peel angle of approximately 180°. Generally, if the peel strength is 40 gf or more and 60 gf or less, the heat sealability can be determined to be good.

[0271] <Evaluation of Anti-blocking Properties>

[0272] The cover tape was wound around a paper tube and placed in an environment of 40°C for 24 hours. Then, the adhesion strength of the front and back sides of the cover tape was confirmed. Specifically, the wound product that could be unwound by the self-weight of the cover tape was evaluated as 0 (good), and the wound product that was tightly adhered but could not be unwound by the self-weight was evaluated as × (poor).

[0273] Table 3 summarizes the formulations and thicknesses of the layers of the cover tape, and Table 4 summarizes the contact angle measurement results and performance evaluation results.

[0274]

[0275] [Table 4]

[0276]

[0277] As shown in Table 4, in the evaluation of the cover tapes of Examples 1' to 4', the electronic components were not easily attached, and the peel strength was sufficiently large. That is, the cover tapes include a base layer containing polyethylene terephthalate, a sealant layer containing a styrene resin, and an intermediate layer provided between the base layer and the sealant layer, and θ h / θ d The cover tape having a value of 0.25 to 0.55 shows that the electronic component is not easily attached and has good heat sealing properties with the carrier tape.

[0278] On the other hand, in θ h / θ d In the evaluation of the cover tape of Comparative Example 1' in which the value of exceeded 0.55 (0.57), sticking of the electronic component was observed.

[0279] Furthermore, in the evaluation of the cover tapes of Examples 1' to 4', the anti-blocking property was good. This is presumably because the contact angle of the exposed surface on the side of the base material layer was appropriately designed in addition to the contact angle of the exposed surface on the side of the sealant layer.

[0280] This application claims priority based on Japanese patent application No. 2019-222697 filed on December 10, 2019 and Japanese patent application No. 2019-222664 filed on December 10, 2019, and all the disclosed contents are incorporated into this specification.

[0281] Description of Reference Numerals

[0282] 10 Cover tape

[0283] 20 Carrier tape

[0284] 21 Grooves

[0285] 100 Electronic component packaging.

Claims

1. A cover tape, wherein: The cover tape comprises: a base layer containing polyethylene terephthalate; a sealant layer containing a styrene resin; and an intermediate layer provided between the base layer and the sealant layer. The arithmetic mean height Sa of the exposed surface on the sealant layer side is 0.05 to 0.35 μm, The arithmetic mean height Sa of the exposed surface on the substrate layer side is 0.01 to 0.2 μm.

2. The cover tape according to claim 1, wherein: The root mean square height Sq of the exposed surface on the sealant layer side is 0.05 to 0.35 μm.

3. The cover tape according to claim 1 or 2, wherein: The intermediate layer contains an olefin-based resin.

4. An electronic component package, wherein: The electronic component package comprises a carrier tape in which the electronic component is stored in a recessed portion and a cover tape according to any one of claims 1 to 3. The sealant layer is bonded to the carrier tape to seal the electronic component.

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