JPH0337760B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to the structure of a carrier for automatically supplying chip-shaped small electronic components to an assembly board, and in particular, the invention relates to the structure of a carrier for automatically supplying chip-shaped small electronic components to an assembly board. This relates to the structure of the agent layer. The common method of traditional paper taping is
A carrier tape whose tape-like support is a pair of 25μ thick polyester films with a uniform heat-activated adhesive layer formed on one side, and a number of holes formed in the central region of the length to fit the shape of the electronic component. The packaging method is to heat and press the tape onto one side of the carrier, and insert the electronic component into the hole from the other side.
Further, the above-mentioned tape is heat-pressed from above so that the electronic component is sandwiched between the side switches. The electronic component thus packaged is one in which one of the carrier tapes is peeled off, the exposed component is suctioned from the inside of the hole with a suction tool, and the component is transferred to an assembly board and bonded thereto. However, recent chip component mounting technology seeks to increase the speed of taping and the speed of mounting onto a board, so it has become necessary to increase the speed of bonding and increase the reliability of bonding. For example, 100 electronic components are being inserted and crimped in one minute, and as more and more electronic components are being crimped, it is now necessary to insert 1000 electronic components in one minute. In addition, the speed of mounting has been improved, so there is no problem such as chip parts adhering to the carrier tape and not being able to be suctioned, or the adhesive peeling off between the cardboard and the carrier tape. It is necessary that there is no peeling between the layers of the cardboard and that the carrier tape peels off at the interface between the carrier tape and the cardboard. Of the above, in order to respond to the first speed increase, it is necessary to perform taping at high temperatures to compensate for the decrease in heat transfer to the bonding interface, and also to reduce the bonding time. There is a growing need for materials with high adhesive properties. On the other hand, this taped product needs to be transported from the parts manufacturing plant to the board insertion place, and considering transportation in summer and winter, for example, 80℃ x 24Hrs to -20℃ x 24Hrs
The chip must be able to withstand high temperature conditions, and the chip components must not adhere to the carrier at all. This invention improves the composition of the adhesive layer of the carrier tape in the carrier structure in order to satisfy these various characteristics. Conventionally, ethylene-vinyl acetate copolymer resin with a high vinyl acetate content has been used as the adhesive layer of carrier tapes, but when trying to obtain high adhesion with high-speed taping, the thermal melting temperature becomes low. However, there were drawbacks such as electronic components adhering to the carrier during summer transportation, and softening at high temperatures and causing peeling. In order to solve these drawbacks, this invention
The lack of adhesiveness was solved by reducing the vinyl acetate content in the ethylene-vinyl acetate copolymer resin or by using polyethylene resin, and by adding a tackifier resin with a high softening point. . To explain this invention specifically, for example, polyethylene ionomer is applied to one side of a 25μ thick polyester film, that is, the side that will be bonded to the film.
The surface to be bonded to the cardboard carrier is coated with ethylene-vinyl acetate copolymer resin with a vinyl acetate content of 6% or polyethylene resin with a high softening point (100°C or higher) as shown in 1, 2, and 3 of Table 1. Using a two-layer extrusion method, a tackifying resin containing an alicyclic hydrocarbon or aliphatic hydrocarbon is used as an adhesive layer.
It was laminated to a thickness of 30μ. In each case, a 5 mm wide tape was pressed at a pressure of 2 kg/cm ² using a rubber sheet having a hardness of 80 degrees to a cardboard carrier (paper type) with a sprocket having a width of 8 mm. At that time, the difference in the surface pressure bonding temperature of the rubber sheet and the pressure bonding time when 100 electronic components were inserted in 1 minute.
Adhesive strength was measured when 1000 parts were inserted. The adhesive strength was measured by fixing the mount and peeling off the tape at a speed of 30 m/min using a universal tensile tester. In addition, the adhesion of this taped product when electronic components were inserted was checked at various temperatures, and the results shown in Table 1 were obtained. In this example, as a comparative example, an adhesive using an ethylene-vinyl acetate copolymer with a vinyl acetate content of 16% (Comparative Example No. 4) and an adhesive using the same adhesive with a vinyl acetate content of 22% (Comparative Example No. 4) were used. Regarding Comparative Example No. 5), a tape laminated with a 30 μm adhesive layer on the surface to be bonded to the cardboard carrier was also tested in the same manner.

【table】

[Table] From the above table, it is seen that in Examples 1 to 3 of this invention and Comparative Example 4, no state of adhesion of the electronic parts to the tape was observed in the adhesion test between electronic parts and tape at 80°C x 24 hours, but in comparison In the case of Example 5, the electronic components adhered to the tape and did not fall. Moreover, since the adhesive strength of Comparative Example 4 was low, when it was formed into a roll, peeling was observed at the lower part of the roll, and the electronic component could not be held. In these formulations, if an ethylene-vinyl acetate copolymer with a vinyl acetate content of 6% or more is used as an adhesive, the adhesive force will be strong and the paper surface may be destroyed or the adhesion at 80℃ x 24 hours I ended up adhering it in the test, which I didn't like. Furthermore, if the amount of tackifying resin is less than 10 times that of the ethylene-vinyl acetate copolymer with a vinyl acetate content of 6% or less, the adhesive strength will be insufficient, while if it exceeds 60 parts, the resistance when peeling off will be insufficient. This was undesirable because it caused the paper to tear or take a long time to peel off. Further, the relationship between the pressure bonding temperature and the adhesive strength of the examples shown in Table 1 is shown in FIGS. 1 and 2. Figure 1 shows the measurement results when 100 electronic parts were inserted into the carrier for 1 minute, and Figure 2 shows the measurement results when 1000 electronic parts were inserted into the carrier for 1 minute.
In both cases, results superior to those of the comparative example were obtained with the invention.

[Brief explanation of the drawing]

FIGS. 1 and 2 are graphs showing the relationship between the pressure bonding temperature and the adhesive force of a carrier tape that is heat-pressed and bonded onto a carrier having electronic components placed in its holes.

Claims (1)

[Claims] 1. After placing chip-shaped small electronic components into holes provided at approximately equal intervals in the longitudinal center region of a tape-shaped cardboard carrier, an adhesive that does not have adhesive properties at room temperature is applied to the tape-shaped support on both sides. In a sandwich-like carrier structure in which a layered carrier tape is laminated, the carrier tape is coated with ethylene containing 6% or less vinyl acetate on the surface of a tape-shaped cardboard carrier.
The main component is a vinyl acetate copolymer or a polyethylene resin, and for every 100 parts of the main component, 10 to 10 parts of a tackifying resin with a softening point of 100°C or higher that is compatible with the main component.
A structure of a carrier for small electronic components characterized by having an adhesive layer that is 60 times thicker.