JP3241220B2 - Cover tape for packaging chip-type electronic components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package having a function of protecting chip-type electronic components from contamination, and aligning and taking out the chip-type electronic components for mounting on electronic circuit boards when storing, transporting and mounting the chip-type electronic components. The present invention relates to a cover tape that is heat-sealed to a plastic carrier tape having a storage pocket.

[0002]

2. Description of the Related Art In recent years, transistors such as ICs, transistors, diodes, capacitors, piezoelectric element resistors,
Chip-type electronic components for surface mounting, such as, according to the shape of the electronic component, a plastic carrier tape formed continuously with embossed pockets that can be stored and a cover tape that can be heat-sealed to the carrier tape It is packaged in a package and used for testing. After peeling off the cover tape of the package, the electronic components of the contents are automatically taken out and surface-mounted on an electronic circuit board. However, with the rapid increase in mounting speed in recent years, the tension applied when peeling the cover tape is tight to prevent poor peeling, and the peeling speed is 0.1 seconds or less / tact, an instantaneous process. Since a large impact stress is applied to the tape, the so-called "tape breakage" problem in which the cover tape is cut has become a major trouble. Conventionally, the thickness of the outer layer has been increased as a countermeasure. However, if the thickness is too large, the sealing property deteriorates, so that no sufficient countermeasure has been taken.

[0003]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has been intensively studied in order to prevent the tape from being broken at the time of peeling and to obtain a cover tape having good sealing properties. An axially stretched film, a layer with excellent impact resistance on the inside, a middle layer with excellent tear resistance on the inside, and a heat-sealable lacquer-type thermoplastic adhesive with conductive fine powder dispersed in the adhesive layer. The inventors have found that a composite film in which the surface resistance value of the adhesive layer having the structure is 10 ¹³ or less and the total light transmittance is 10% or more can be a cover tape having good characteristics, and completed the present invention. Things.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a cover tape which can be heat-sealed on a plastic carrier tape in which storage pockets for accommodating chip-type electronic components are continuously formed. Is a biaxially stretched film of either polyester or polypropylene, the inside of which is an impact resistance improving layer with excellent impact resistance, which is either a stretched or unstretched film of polypropylene or nylon, and As an intermediate layer having excellent tear resistance, polyethylene, polyethylene vinyl acetate copolymer, ethylene-acrylic copolymer, ionomer, styrene-butadiene-styrene copolymer,
A styrene-ethylene-butylene-styrene block copolymer, wherein the adhesive layer is heat-sealable to a plastic carrier tape, such as a polyurethane resin, an acrylic resin, a polyvinyl chloride resin, and an ethylene vinyl acetate resin. , A polyester-based resin, or a heat-sensitive lacquer-type chip-type electronic device in which a conductive fine powder of tin oxide or zinc oxide is dispersed in the adhesive. A part packaging cover tape, wherein the amount of the conductive fine powder added is 10 to 100 parts by weight based on 100 parts by weight of the base resin of the adhesive.
0 parts by weight, the surface resistance of the adhesive layer is 10 ¹³ Ω / □ or less, and the adhesive strength between the adhesive of the cover tape and the sealing surface of the carrier tape is between the intermediate layer and the adhesive layer of the cover tape. The adhesion strength is larger than the adhesion strength, and the interlayer adhesion strength between the intermediate layer and the adhesive layer of the cover tape is 10 to 10 mm per seal width.
120 gr, and the total light transmittance (J
IS K7105) is 10% or more.

[0005]

FIG. 1 is a diagram showing components of a cover tape 1 according to the present invention.
In the description, the outer layer 2 is a biaxially oriented polyester film or a biaxially oriented polypropylene film, and is a film having a thickness of 6 to 25 μm and excellent transparency and excellent heat resistance. When the outer layer is less than 6 μm, the rigidity is lost, and when it exceeds 25 μm, the outer layer is too hard and the seal becomes unstable. Inside is an impact-resistant layer 3 with excellent impact resistance.
Is a stretched or unstretched film of polypropylene or nylon, and is a transparent film having a thickness of 6 to 50 μm and excellent in tear resistance. When the impact resistance improving layer 3 is less than 6 μm, the tear resistance is insufficient, and when it exceeds 50 μm, the sealing property becomes unstable. By the way, there is a biaxially stretched nylon film as a film having excellent transparency and heat resistance and impact resistance. However, when it is used as an outer layer, it has poor slipperiness with a heat seal iron, and is particularly suitable for a sliding type sealing machine. Absent. In addition, if the outer layer is used because of its high hygroscopicity, the problem of blocking occurs, so that it is not suitable for the outer layer. The sides of the outer layer 2 and the impact resistance improving layer 3 that are in contact with each other may be corona treated as necessary.
By applying a surface treatment such as a plasma treatment or a sand blast treatment, the adhesion can be improved. Further, as the intermediate layer 4 having excellent tear resistance, polyethylene, polyethylene vinyl acetate copolymer, ethylene-acryl copolymer, ionomer, styrene-butadiene-styrene copolymer, styrene-ethylene-butylene-styrene block copolymer are used. A film having a thickness of 10 μm or more, preferably 20 to 60 μm is good. If the thickness is less than 10 μm, there is no effect of tear resistance, and if the thickness is more than 60 μm, heat sealability is deteriorated.

The adhesive layer 5 is made of a heat-sealable lacquer-type thermoplastic adhesive of a polyurethane resin, an acrylic resin, an ethylene vinyl acetate resin, a polyvinyl chloride resin, or a polyester resin alone or in combination. It has the property of being capable of being heat-sealed to a plastic carrier tape as a mating material. and,
Either tin oxide or zinc oxide conductive fine powder is uniformly dispersed in the adhesive, and the surface resistance of the adhesive layer after film formation must be at least 10 ¹³ Ω / □ or less. ,
More preferably, the range is 10 ⁶ Ω / □ to 10 ⁹ Ω / □. If it exceeds 10 ¹³ Ω / □, the electrostatic effect becomes extremely poor and the desired performance cannot be obtained. Further, the addition amount is 10 to 1000 parts by weight, more preferably 100 to 300 parts by weight, based on 100 parts by weight of the base resin of the adhesive, depending on the surface resistance characteristics. If the amount is less than 10 parts by weight, no electrostatic effect is exhibited, and if it is more than 1000 parts by weight, dispersibility in an adhesive becomes extremely poor, which is not suitable for production. In addition, since the electrostatic treatment material itself has conductivity, it has a semi-permanent electrostatic effect, does not cause bleeding and the like, and does not affect the sealing property. The surface resistance value of the adhesive layer is 10 ¹³ Ω / □ or less. Therefore, even when the electronic component comes into contact with the cover tape during the transportation of the electronic component encapsulated in the carrier tape with the cover tape, or when the electronic component is picked up by peeling off the cover tape. Also, no static electricity is generated, and the electronic components can be protected from static electricity. In order to further enhance the electrostatic effect, an antistatic treatment layer or a conductive layer may be provided on the outer layer side, that is, on the front and back surfaces of the biaxially stretched film. The method of forming the heat-sealable adhesive may be either a melt film forming method or a solution film forming method, but is preferably a solution film forming method from the viewpoint of dispersibility of the conductive fine powder.

In the sealing and peeling process of the cover tape, first, the cover tape 1 is attached to the carrier tape 6.
Is continuously sealed in a rail shape on either side with a width of about 1 mm (Fig. 2). Next, when the cover tape 1 is peeled off from the carrier tape 6 at the time of peeling, the adhesive strength between the adhesive layer 5 of the cover tape 1 and the sealing surface of the carrier tape 6 is determined by the intermediate layer 4 and the adhesive layer 5 of the cover tape 1. When the peel strength is smaller than the interlayer adhesion strength of the adhesive tape, the peel-off strength corresponds to the adhesive strength between the adhesive layer 5 of the cover tape 1 and the sealing surface of the carrier tape 6, and the peeling is performed by interfacial peeling, which is currently the most common peeling mechanism. Will be On the other hand, when the adhesive strength between the adhesive layer 5 of the cover tape 1 and the sealing surface of the carrier tape 6 is larger than the interlayer adhesive strength between the intermediate layer 4 and the adhesive layer 5 of the cover tape 1 as in the present invention, the film is formed. Only the sealed portion of the adhered adhesive layer 5 remains on the carrier tape (FIG. 4), and the cover tape after peeling (FIG. 3) has a shape in which only the heat-sealed portion of the adhesive layer 5 has been dropped. Peeling is carried out by peeling or peeling.

That is, the peel-off strength corresponds to the interlayer adhesion strength between the adhesive layer 5 and the intermediate layer 4, and the peeled surface is designed in the cover tape. Therefore, a stable peel-off strength can be obtained without being affected by the sealing state of the cover tape and the carrier tape. in this case,
The interlayer adhesion strength between the intermediate layer and the adhesive layer of the cover tape is preferably 10 to 120 gr, more preferably 10 to 7 gr per 1 mm of the seal width.
An adhesive is selected so as to be 0 gr. 10g peel strength
If it is lower than r, there is a problem that the cover tape comes off when the package is transferred, and the electronic components as contents fall off. Conversely, if it is higher than 120 gr, the carrier tape will vibrate when the cover tape is peeled off, causing a phenomenon of jumping out of the storage pocket immediately before mounting the electronic component, that is, a jumping trouble. According to this transfer peeling mechanism, the dependency on the sealing condition is lower than that of the conventional interface peeling, and
It is possible to obtain the target performance in which the peel-off strength does not change with time due to the storage environment. Further, since the cover tape is configured so that the total light transmittance is 10% or more, preferably 50% or more, the internal electronic components sealed in the carrier tape can be visually or mechanically confirmed. If it is lower than 10%, it is difficult to confirm the electronic components inside.

[0009]

EXAMPLES Examples of the present invention are shown below, but the present invention is not limited by these examples. << Examples 1 to 6 and Comparative Examples 1 to 6 >> In the examples, a biaxially stretched film is combined with the outer layer, and a stretched or unstretched film is combined with the impact resistance improving layer. On the side, an adhesive layer was formed into a solution having a thickness of 2 μm by a gravure coater. In the comparative examples, those with and without the biaxially stretched film or unstretched film, the impact resistance improving layer and the intermediate layer in the outer layer were examined. The layer configurations of these examples and comparative examples are shown below. About the obtained composite film, after slitting to 13.5 mm width, PVC of 16 mm width
The carrier tape was heat-sealed, and the presence or absence of tape breakage was determined by a high-speed peeling machine (42000 mm / min), and the peel strength was measured (measuring speed: 300 mm / min). Heat sealing ^{conditions: 140 ℃ / 1kg / cm 2} / 1sec, sliding seals, seal width 1 mm × 2 Peel conditions: 180 ° Peel, Peel Speed 300 mm / mi
n, number of samples: 3 Further, the surface resistance value of the adhesive layer side and the visible light transmittance of the prototype cover tape were measured, and the results are shown in Tables 1 and 2.

Layer configuration: outer layer / impact resistance improving layer / intermediate layer / adhesive layer in order, where // indicates no layer. Layer thickness: outer layer 12 μm, impact resistance improving layer 15 μm, intermediate layer 30 μm , Adhesive layer 2μm ・ The type and amount of the conductive fine powder in parentheses after the adhesive layer are shown in the parentheses. The amount of the additive is based on 100 parts by weight of the thermoplastic resin of the adhesive layer (parts by weight). Street.・ PET: Polyethylene terephthalate (unstretched) ・ O-PET: Biaxially stretched polyethylene terephthalate ・ PP: Polypropylene (unstretched) ・ OPP: Biaxially stretched polypropylene ・ NY: Nylon (unstretched) ・ ONY: Biaxially stretched nylon EVA: ethylene vinyl acetate copolymer PVC: polyvinyl chloride SBS: styrene-butadiene-styrene copolymer SEBS: styrene-ethylene-butylene-styrene copolymer SnO ₂ : tin oxide TiO ₂ : oxidation Titanium / ZnO ₂ : Zinc oxide

Example 1 O-PET / OPP / LDPE / PVC adhesive (Sn
O ₂ : 120) [Example 2] O-PET / ONY / EVA / acrylic adhesive (Sn
O ₂ : 200) [Example 3] O-PET / PP / Ionomer / PET adhesive (Z
nO _2: 300) [Example 4] O-PET / NY / EMMA / polyurethane adhesive (ZnO _2: 500) [Example 5 OPP / ONY / SBS / EVA-based adhesive (SnO _2: 7
Example 6 OPP / NY / SEBS / EVA adhesive (SnO ₂ : 9)
Comparative Example 1 O-PET // EVA / PET adhesive (SnO ₂ : 50)
0) [Comparative Example 2] OPP /// acrylic adhesive (ZnO ₂ : 70) [Comparative Example 3] O-PET // LDPE / PVC adhesive (SnO ₂ :
5) [Comparative Example 4] OPP / ONY // polyurethane adhesive (ZnO ₂ : 1)
200) [Comparative Example 5] O-PET / PP / SEBS / EVA -based adhesive (surfactant: 2) [Comparative Example 6] ONY // EVA / acrylic adhesive (SnO _2: 500)

Table 1  Example1 2 3 4 5 6 High-speed peeling test table None None None None None None Peel strength Initial value 45 38 15 60 41 28 40 ° C-90%, 30 days 55 45 28 62 38 36 60 ° C, 30 days 68 50 55 75 75 80 75 Peeling method Transfer Transfer Transfer Transfer Transfer Transfer Surface resistance (Ω / □) 10⁹ 10⁸ 10⁶ 10⁷ 10^Five 10^Five  Total light transmittance (%) 88.0 85.2 76.3 50.7 25.8 10.5

Table 2 Comparative Example 1 2 3 4 5 6 High-speed peeling test test table Yes Yes Yes Yes No Yes Peel strength Initial value 59 85 63 5 45 * 40 ° C-90%, 30 days 56 120 45 2 9 11 60 ° C, 30 days 63 157 98 10 68 98 peeling method transfer surface transferring surface transfer transferring surface resistivity of the adhesive layer ^{(Ω / □) 10 7 10} 13 10 14 10 4 10 14 10 6 total light transmittance (%) 18.6 86.2 89.7 6.8 89.6 43.5 Note: The * mark shows bad slippage and wrinkles during sealing, making sealing impossible

[0014]

According to the present invention, there is no danger of a tape breakage problem even if the speed of the mounting machine is increased, the adhesive layer is electrostatically treated, and the contact between the electronic component and the cover tape or The peel-off strength can be arbitrarily set within the range of 10 to 120 gr per 1 mm by the combination of the heat seal lacquer adhesive and the intermediate layer in that the static electricity generated at the time of peeling the cover tape is suppressed and the sealing property is not affected. Because it can be set, and because the peel-off strength is determined by the adhesion strength between the layers in the cover tape, it is not affected by the sealing conditions with the carrier tape. In addition to solving the problem of tape breakage, the problem that the peel-off strength is greatly dependent on the sealing conditions,
In addition, it is possible to solve the problem that changes with time due to the storage environment, the problem of contact between the electronic component and the cover tape, or the problem of static electricity generated when the cover tape is peeled off, and obtain a stable peel-off strength.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a layer structure of a cover tape of the present invention;

FIG. 2 is a sectional view showing a use state of the cover tape of the present invention bonded to a carrier tape.

FIG. 3 is a cross-sectional view of the cover tape of the present invention showing a state where the cover tape is peeled off from the carrier tape.

FIG. 4 is a cross-sectional view of the carrier tape showing a state where the cover tape of the present invention is peeled off.

Claims (1)

(57) [Claims] 1. A cover tape which can be heat-sealed on a plastic carrier tape in which storage pockets for accommodating chip-type electronic components are continuously formed, wherein the cover tape has an outer layer made of either polyester or polypropylene. A biaxially stretched film, the inner side of which is an impact-resistant layer with excellent impact resistance, which is either a stretched or unstretched film of polypropylene or nylon, and the inner side of which is an intermediate layer with excellent tear resistance Is any one of polyethylene, polyethylene vinyl acetate copolymer, ethylene-acryl copolymer, ionomer, styrene-butadiene-styrene copolymer, styrene-ethylene-butylene-styrene block copolymer, wherein the adhesive layer is Polyurethane resin that can be heat sealed to plastic carrier tape An adhesive made of an acrylic resin, a polyvinyl chloride resin, an ethylene vinyl acetate resin, a polyester resin, or a combination thereof, wherein the adhesive contains a conductive material such as tin oxide or zinc oxide. Fine powder is dispersed, the amount of the conductive fine powder to be added is 10 to 1000 parts by weight with respect to 100 parts by weight of the base resin of the adhesive, and the surface resistance value of the adhesive layer is 10 ¹³ Ω / □ or less. The adhesive strength between the adhesive layer of the cover tape and the sealing surface of the carrier tape is greater than the interlayer adhesive strength between the intermediate layer and the adhesive layer of the cover tape, and the interlayer adhesive strength between the intermediate layer and the adhesive layer of the cover tape is sealed. 10 to 120 g per 1 mm width
r, wherein the total light transmittance of the cover tape is 10% or more.