JP4899593B2 - Cover tape for packaging electronic parts - Google Patents

Description

  The present invention is an electronic component packaging cover that can be heat-sealed among packaging bodies that have the function of protecting electronic components from contamination and arranging and taking them out for mounting on an electronic circuit board when storing, transporting, and mounting the electronic components. It is about tape.

  Starting with ICs, surface mount electronic components such as transistors, diodes, capacitors, and piezo-resistors have been continuously formed with trays and pockets with embossed pockets that can be accommodated according to the shape of the electronic components. It is packaged and supplied in a package comprising a carrier tape and a cover tape that can be heat sealed to the carrier tape. A carrier tape that wraps electronic components is usually wound on a reel made of paper or plastic, and the state is maintained until the mounting process. The electronic components of the contents are automatically taken out from the carrier tape after the cover tape is peeled off and mounted on the surface of the electronic circuit board.

  In recent years, as electronic parts have become smaller and more functional, the number of electrostatic sensitive parts has increased, causing process troubles caused by static electricity. Among the electronic components, particularly in the field of semiconductor components, it has become difficult to maintain the conventional electrostatic breakdown characteristics with higher integration / miniaturization and lower operating voltage. Therefore, in the production process of a semiconductor component manufacturer and the assembly process of a semiconductor component user, there is a problem of component destruction due to electrostatic discharge (ELECTRO STATIC DISCHARGE, hereinafter referred to as ESD).

  Outside of the semiconductor parts field, the destruction of electronic parts due to ESD was rare, but with the recent downsizing and higher functionality of electronic equipment, the mounting electronic parts are also rapidly becoming smaller and lighter. Depending on the electronic components, the electrification between the cover tape and the parts due to friction during transportation and the static electricity generated when the cover tape is peeled off may cause the electronic parts to adhere to the charged cover tape and pick up. It has become a problem to cause process troubles such as defects.

  As for the static electricity which is a problem in these, as disclosed in Patent Document 1, there is also a method in which the resin composition is adjusted and a certain composition is used to suppress charging at the time of peeling for a certain device. However, it is necessary to consider not only the device that the cover tape contacts but also the carrier tape that is to be sealed, but the charged voltage changes depending on the combination when different substances come in contact from the viewpoint of the charge series. Therefore, for example, the material of the carrier tape that seals the cover tape varies in its effect, and the problem due to static electricity cannot be solved depending on the carrier tape used. In Patent Document 2, a technique for preventing electrostatic induction from an externally charged material is taken on the premise that a surfactant or the like is kneaded into the intermediate layer. Depending on the case, the bleed of the surfactant from the intermediate layer may affect the physical properties of the film itself, resulting in poor sealing. Further, as disclosed in Patent Document 3, there is a technique for preventing electrostatic by inserting an ion conductive layer mainly composed of a polymer having a hydrophilic group between the layers. In this method, the polymer having the hydrophilic group is used. Since it is necessary to connect the gaps with moisture, the effect is not exhibited unless there is some humidity. Furthermore, in Patent Document 4, a π-electron conjugated conductive polymer layer is provided on the upper surface and the lower surface of the base layer of the cover tape. When the conductive polymer layer is laminated on the upper surface of the cover tape, the cover tape is removed. When sealing, depending on the sealing conditions, the conductive layer peels off due to the heat of the thermal iron, and when it is laminated on the lower surface, the sealing performance is affected.

When the peeling mechanism of the cover tape is a mechanism based on the interface or transfer, peeling between different kinds of substances is caused in the same manner as described above, so that the charged voltage at the time of peeling becomes large, resulting in the destruction of the electronic component due to ESD. In some cases, electronic parts adhere to the charged cover tape and cause troubles such as pickup failure.
JP 2003-128132 A JP 2000-142786 A Japanese Patent Application Laid-Open No. 08-127755 JP 2001-301819 A

  In order to solve the problem of sticking or breaking of electronic parts caused by static electricity as described above, the present invention is charged by friction between the cover tape and the electronic parts or charged when the cover tape is peeled from the carrier tape. Is to provide a cover tape capable of suppressing the moisture absorption state of the film and the carrier tape material.

The present invention
(1) A cover tape comprising at least four layers of a base material layer, an intermediate layer, an adhesive layer, and a heat sealant layer, wherein the heat sealant layer is an outermost layer, and between the heat sealant layer and the previous base material layer There is the intermediate layer, the adhesive layer is between layers other than the heat sealant layer, and the surface resistance value of the surface of the heat sealant layer is 10 ⁴ to 10 ¹² Ω / □ (23 ° C.-15% RH environment). Yes, the surface resistance value of the adhesive layer is 10 ¹⁰ Ω / □ or less (under an environment of 23 ° C.-15% RH), and the charged voltage is 1% or less when charged by applying 5 kv to the surface of the heat sealant layer. The cover tape is peeled off from the carrier tape at 300 mm / min after the cover tape is heat-sealed through a carrier tape in which electronic components are stored and a heat sealant layer. An electronic component packaging cover tape, wherein the absolute value of the charged voltage generated during peeling of when the is less than 100 V.
As a more preferable form,
(2) The electronic component packaging cover tape according to (1), wherein the base material layer is at least one kind of polyester, polypropylene, and nylon biaxially stretched films.
(3) The cover tape for electronic component packaging according to (1) or (2), wherein the heat sealant layer contains one or more of tin oxide, zinc oxide, titanium oxide, and carbon.
(4) The electronic component packaging cover tape according to (1), (2) or (3), wherein the peeling occurs due to cohesive failure of the intermediate layer,
(5) A cover tape for packaging electronic parts in which the charged voltage on the cover tape side when the cover tape and the electronic parts are rubbed at 300 rpm for 1 minute is 50 V or less.

  According to the present invention, it is possible to prevent an electrostatic induction phenomenon on the cover tape from an electronic component charged by friction or the like without depending on humidity. In addition, since the cover tape is peeled off by the cohesive failure mechanism, it is possible to obtain a stable peeling charge suppression effect without being influenced by the material of the carrier tape. It is possible to prevent the electronic components from being damaged due to sticking of the components and ESD.

  The components of the cover tape 1 of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of the layer structure of the cover tape of the present invention. FIG. 2 is a cross-sectional view showing a use state of the cover tape of the present invention heat-sealed to the carrier tape 6.

In the present invention, the electronic components are, for example, ICs, transistors, diodes, capacitors, piezoelectric element registers, and the like.
In FIG. 1, the base material layer 2 may be laminated with a plurality of films in order to impart the performance to the cover tape when the cover tape needs rigidity and tear resistance. A transparent and highly rigid film having a thickness of 5 to 30 μm is preferable. When the thickness is 5 μm or less, the rigidity is lost and the cover tape is easily cut. If it exceeds 30 μm, it may be too hard and the seal may become unstable. Examples of the material used for the base material layer include a biaxially stretched polyester film, a nylon film, and a polyolefin film, but a biaxially stretched polyethylene terephthalate film is preferable because of heat resistance during heat sealing. In addition, when a base material layer is two or more layers, a different material may be sufficient.

The heat sealant layer 4 is in the outermost layer of the cover tape and is usually only one layer. The heat sealant layer is, for example, an acrylic resin or a polyester resin, an antistatic agent, a metal filler such as tin oxide, zinc oxide, titanium oxide, carbon, and polyoxyethylene alkylamine, quaternary ammonium, alkyl sulfonate, etc. Any one of these surfactants or a mixture thereof is added, and the surface resistance value is adjusted to 10 ⁴ to 10 ¹² Ω / □ (23 ° C.-15% RH). Of the above, carbon includes fillers of various shapes made of carbon such as carbon black, white carbon, carbon fiber, and carbon tube. In order to prevent blocking, oxide particles containing silicon, magnesium or calcium as a main component, for example, silica, talc, etc., or any one of polyethylene particles, polyacrylate particles and polystyrene particles, or an alloy thereof. May be added to the above formulation. As a method for forming the layer, a gravure coating method is desirable.

If the surface resistance value of the heat sealant layer surface is less than 10 ⁴ Ω / □, the resistance is too low when electric charges are generated outside the taping product (the carrier tape sealed with the cover tape). May cause electrostatic breakdown to conduct electricity to the electronic components in the area, and if it exceeds 10 ¹² Ω / □, the electrostatic diffusion performance will not be sufficient, and the desired static elimination performance will not be demonstrated. Becomes charged, causing trouble.

  There is an intermediate layer between the heat sealant layer and the substrate layer. The intermediate layer is at least one layer, and is a layer that causes cohesive failure when peeled after heat sealing, and is preferably adjacent to the heat sealant layer. Examples of the material of the intermediate layer include resin alloys having poor compatibility, such as polyethylene and styrene alloys. In addition, you may add a compatibilizing agent etc. for peel strength adjustment. The thickness of the intermediate layer is 5 to 50 μm. As the method for forming the intermediate layer, the extrusion laminating method is desirable from the viewpoint of efficiency and low cost.

There is an adhesive layer between layers other than the heat sealant layer. The adhesive layer has a surface resistance value of 10 ¹⁰ Ω / □ or less (under an environment of 23 ° C.-15% RH), and FIGS. 1 and 2 are examples of the present invention and are provided between the base material layer and the intermediate layer. However, when the base material layer and the intermediate layer are actually composed of two or more layers, they may be provided only in any one of the layers. The adhesive layer includes a resin and a conductive substance, and examples of the material of the resin include urethane-based dry laminate or anchor coat adhesive resins. Generally, a polyester composition such as a polyester polyol or a polyether polyol; A combination of isocyanate compounds. Examples of the conductive substance include metal fillers such as tin oxide, zinc oxide, titanium oxide, and carbon, and organic conductive substances such as a conductive polymer, a mixture thereof, and a substance containing them. Carbon includes various shape fillers made of carbon such as carbon black, white carbon, carbon fiber, and carbon tube. The conductive material may be added after mixing the polyester composition and the isocyanate compound, but it is preferable to add the conductive material in advance to any of the resins in view of the stability of the reaction conditions. Examples of the formation of the adhesive layer include coating.

The surface resistance value of the adhesive layer is 10 ¹⁰ Ω / □ or less. If the surface resistance value of the adhesive layer exceeds 10 ¹⁰ Ω / □, the electrical conductivity is not sufficient, the effect of preventing the electrostatic induction phenomenon described later is not exhibited, the cover tape is charged, ESD, pickup failure, etc. It was found that it causes trouble. Further, since the production process environment for peeling the cover tape may become dry in winter, the surface resistance value must be kept at 10 ¹⁰ Ω / □ or less even under low humidity.
The adhesive layer is inserted as a dry laminate adhesive if the inserted layer is between a stretched film and a stretched film. If it is a stretched film-intermediate layer, it is inserted as an anchor coating agent.

  Among cover tapes currently on the market, the mechanism for peeling from the carrier tape is classified into three types: interface peeling type, transfer peeling type, and cohesive failure type. Interfacial peeling type means that the sealing surface of the cover tape and carrier tape is peeled off.Transfer peeling type means that the heat sealant material layer itself is transferred to the carrier tape at the time of peeling. The heat sealant layer is different from the heat sealant layer or is peeled off when the heat sealant layer itself is broken. Comparing the parts related to electrification when peeling the cover tape heat-sealed on the carrier tape, which has advantages and disadvantages for each type, the cohesive failure mechanism is the same compound as the other interface peeling mechanism and transfer peeling mechanism Therefore, it is difficult to be charged from the viewpoint of the charging series, and it is preferable as a cover tape. When the cover tape is peeled from the carrier tape at 300 mm / min, the absolute value of the charged voltage generated at the peeling is preferably suppressed to 100 V or less. Further, since the peeling always occurs in the same cohesive failure layer, a difference in peeling voltage due to the carrier tape material hardly occurs.

The electrostatic induction means that an opposite charge is generated on the surface of the insulator when the charged object approaches the insulator (inductive charging). At this time, electric lines of force are generated between the charged object and the insulator. This is one of the causes of static electricity generation. If a good dielectric is inserted in the meantime, the opposite electric lines of force are generated in the dielectric, and when viewed comprehensively, the electric lines of force can be counteracted. Can be suppressed.
In today's world where high-speed electronic component mounting is progressing, the effect of preventing electrostatic induction is proportional to the dielectric property of a good dielectric. If the dielectric property is low (high surface resistance), the prevention effect is weakened and the cancellation time ( The problem that charging decay time) becomes long has appeared. In the present invention, by laminating an adhesive layer having a surface resistance value of 10 ¹⁰ Ω / □ or less, when charging is performed by applying 5 kv to the surface of the heat sealant layer, the time during which the charged voltage becomes 1% is 0.1%. It was possible to make it less than a second, and the effect of preventing electrostatic induction could be exhibited.

  By inserting the layer having the effect of preventing electrostatic induction, when the electronic component is packed and transported with the carrier tape and the cover tape, the static electricity from the electronic component charged by the friction between the electronic component and the cover tape to the cover tape The electric induction phenomenon can be prevented, and the absolute value of the voltage on the cover tape side when it is rubbed for 1 minute with an electronic component (size: 12 mm x 12 mm, package: PLCC (plastic package) type) at 300 reciprocations / minute Can be made 50V or less.

Examples of the present invention are shown below, but the present invention is not limited to these examples.
<Example 1> A biaxially stretched polyester film having a film thickness of 25 μm is used as a base material layer, a paint in which zinc oxide (20% added amount) is added to a urethane adhesive as an adhesive layer, and polyethylene and polystyrene as an intermediate layer. Was formed into a film thickness of 30 μm by an extrusion laminating method (extrusion temperature: 280 ° C.). A heat sealant layer in which tin oxide (addition amount 20%) is added to an acrylic resin is formed on the above-mentioned film with a film thickness of 1 μm by the gravure coating method, and the cover having the layer structure shown in FIG. I got a tape.

  After slitting the obtained cover tape to a width of 13.5 mm, the electronic component is inserted into a PS carrier tape (material: carbon kneaded polystyrene) having a width of 16 mm, and the strength at the time of peeling (peeling speed: 300 mm / min) is 40 cN. The sample was prepared by adjusting the heat seal temperature so that the cover tape was heat sealed (0.4 mm width × 8 mm length, 2 rows, 2 degrees). A vibration of 300 reciprocations / minute was applied for 1 minute, and the charged voltage on the cover tape after removing the device was measured (cover tape surface voltage after friction). Moreover, the peeling mechanism at the time of peeling was observed, and the peeling voltage generated at the time of peeling was measured. The charged voltage is shown as an absolute value. The surface resistance values of the front and back surfaces were measured before slitting the cover tape. Further, the surface resistance of the adhesive layer was measured before the film was formed and the adhesive layer was formed and the resin was laminated.

<Examples 2 to 3 and Comparative Examples 1 to 5> In the same manner as in Example 1, cover tapes having the configurations described in Tables 1 and 2 were prepared and evaluated in the same manner as in Example 1.

<Comparative Example 6> A structure in which 1 part by weight of a nonionic antistatic agent was kneaded into an intermediate layer composed of an alloy of PE and PS with the same configuration as in Example 2 was prepared. An environmental storage test (storage environment: 60 ° C., 1 week) was performed on the samples of Example 2 and Comparative Example 6. Prior to environmental storage, both Example 2 and Comparative Example 6 had a heat seal temperature of 180 ° C. and a strength of 40 cN, but after storage there was no change in the structure of Example 2, but Comparative Example 6 In the structure of No. 1, only a strength of 10 cN was obtained with a seal at 180 ° C.

The measurement of the charged voltage at the time of peeling and friction was performed using a surface potentiometer manufactured by TREK Co., Ltd. and setting the distance between the sample and the probe to 1 mm.
The surface resistance value was measured using a surface resistance measuring device manufactured by SIMCO.
The decay time measurement when the charged voltage of the cover tape was reduced to 1% when charged to 5 kv was measured using an electrostatic decay measuring device manufactured by ETS Corporation.
The evaluation results of Examples and Comparative Examples are shown in Table 1 and Table 2.

In addition, the symbols and display names in Tables 1 and 2 indicate the following.
o-PET: Biaxially stretched polyethylene terephthalate o-Ny: Biaxially stretched nylon PE: Polyethylene PS: Polystyrene

  The present invention is used as a cover tape that can be heat-sealed out of a package having a function of protecting electronic components from contamination, arranging them for mounting on an electronic circuit board, and taking them out when storing, transporting, and mounting the electronic components. In particular, since it has a structure that pays attention to static electricity generated at the time of peeling or after rubbing, it is suitable as a cover tape used when packing an electrostatic sensitive device that tends to increase in recent years on a carrier tape.

It is sectional drawing which shows the layer structure of the cover tape of this invention, and is an example. It is sectional drawing which heat seals the cover tape of this invention to a carrier tape, and shows the use condition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cover tape 2 Base material layer 3 Intermediate | middle layer 4 Heat sealant layer 5 Adhesive layer 6 Carrier tape 7 Electronic component

Claims (2)

A cover tape comprising at least four layers of a base material layer, an intermediate layer, an adhesive layer, and a heat sealant layer, and the base material layer is at least one kind of a biaxially stretched film of polyester, polypropylene, and nylon the heat sealant layer is in the outermost layer, wherein there is the intermediate layer between the heat sealant layer and the front SL base layer, the adhesive layer is between the layers of the layer other than the heat sealant layer, said heat sealant The surface resistance value of the layer surface is 10 ⁴ to 10 ¹² Ω / □ (under 23 ° C.-15% RH environment), and the surface resistance value of the adhesive layer is 10 ¹⁰ Ω / □ or less (under 23 ° C.-15% RH environment). ), And when 5 kv is applied to the surface of the heat sealant layer for charging, the decay time when the charged voltage becomes 1% or less is 0.1 second or less, and the cover tape is stored in the electronic component. The absolute value of the charged voltage generated when peeling from the carrier tape at 300 mm / min after heat sealing through the carrier tape and the heat sealant layer is 100 V or less and the peeling is a cohesive failure of the intermediate layer causing stiffness, for packaging electronic components cover tape, wherein the charged voltage of the cover tape side when the cover tape and the electronic components were rubbed for one minute at 300rpm is 50V or less by. The cover tape for electronic component packaging according to claim 1, wherein the heat sealant layer contains at least one of tin oxide, zinc oxide, titanium oxide, and carbon.

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