JP2589021B2 - 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 can be sealed with a plastic carrier tape having a storage pocket.

[0002]

2. Description of the Related Art In recent years, chip-type electronic components for surface mounting, such as ICs, transistors, diodes, capacitors, and piezo-electric resistors, have been continuously formed with embossed pockets that can be accommodated according to the shape of the electronic components. The package is supplied in a package made of a plastic carrier tape formed in the above and a cover tape sealable to the carrier tape. The electronic components of the contents are transported and stored in a state of being housed in a carrier tape, and after the cover tape of the package is peeled off, they are automatically taken out and surface-mounted on a circuit board.

[0003] Conventionally, the required characteristics of a cover tape for a carrier tape are sealing stability and static electricity rather than moisture proof and baking heat resistance, because the electronic components to be housed are less likely to cause a sealing resin crack during solder mounting due to moisture absorption. Measures and transparency were the main characteristics. However, electronic components to be formed into chips have gradually spread from circuit components such as capacitors and resistors to highly integrated components such as ICs and LSIs. The thickness of these highly integrated components from the sealing resin surface to the silicon wafer is becoming thinner and thinner due to their lightness, and the probability of cracks occurring due to moisture absorption of the sealing resin during solder mounting is high. After passing through a baking process at 120 to 140 ° C. with a conductive tray, the tape is taped on a carrier tape, and further sealed and transported and stored in an Al moisture-proof bag called a dry pack to prevent moisture absorption of the sealing resin. In addition, since it takes time to mount the electronic components on one reel of the carrier tape at the time of mounting, it is necessary to repeat the process of transferring to a tray again, baking and using the tray. For this reason, the process is complicated, and two steps such as further packaging and re-baking of the carrier tape are required, and simplification of the process while maintaining moisture proof of the product has been strongly desired.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has been studied as a result of obtaining a cover tape having excellent moisture-proof properties while maintaining the sealing properties of a conventional cover tape. With the knowledge that a cover tape composed of a composite sheet of two or more layers having a metal layer having a moisture-proof function on at least one of the cover tapes has good characteristics, the present invention has been completed. is there.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a cover tape which can be sealed on a plastic embossed carrier tape in which storage pockets for accommodating chip-type electronic components are continuously formed. A composite sheet of two or more layers containing any one of Al, Cu, Zn, Sn, Ni, Ti, Si or a compound thereof, and the moisture permeability of the composite sheet is JIS Z 0208 40
1.5 g / m 2 · 24 hr by the measurement method at 90 ° C. and 90% RH
The following is a chip-type electronic component packaging cover tape which is excellent in moisture proofness and suppresses moisture absorption of electronic components in pockets during a product transportation / storage process.

[0006]

The components of the cover tape 1 of the present invention will be described with reference to FIG.
It is a biaxially stretched film that becomes a base layer of a cover tape such as nylon, and is a transparent and highly rigid film having a thickness of 6 to 100 μm. If it is less than 6 μm, the rigidity is lost and
If it exceeds μm, it is too hard and the seal becomes unstable. The side in contact with the first layer 2 of the moisture-proof layer 3 is corona-treated if necessary,
A surface treatment such as a plasma treatment, a sand blast treatment, and a chemical treatment can be performed to improve the adhesion to the moisture-proof layer 3. Further, the surface of the first layer 2 may be coated with an antistatic agent, a conductive powder or the like for the purpose of an antistatic treatment.

The moisture-proof layer 3 is made of Al, Cu, Zn, Sn, N
It is a metal layer made of any one of i, Ti, Si or a compound thereof and having a thickness of 0.01 to 100 μm. If it is less than 0.01 μm, the moisture-proof function is insufficient, and if it exceeds 100 μm, it is too hard and the seal becomes unstable. The side of the moisture-proof layer 3 that contacts the first layer 2 has the purpose of improving the adhesion between the two layers.
Surface treatment such as corona treatment, plasma treatment, sand blast treatment, and chemical treatment may be performed. For the purpose of imparting antistatic performance, an antistatic agent, a conductive powder or the like may be kneaded in the resin of the moisture-proof layer 3 or coated on the surface.

The sealant layer 4 is made of a transparent thermoplastic resin (eg, polyurethane resin, acrylic resin, ethylene vinyl acetate resin, polyvinyl chloride resin, polyester resin, polystyrene resin, ABS).
And a layer that can be sealed to a plastic carrier tape of a mating material by each unit or a combination thereof.
The sealant may be any of a normal temperature adhesive type, a film type, a hot melt type, and a heat seal lacquer type. Also, for the purpose of giving antistatic performance,
An antistatic agent, conductive powder or the like may be kneaded in the resin of the sealant layer 4 or coated on the surface.

Regarding the moisture-proof property of the cover tape, the moisture permeability of the composite film constituting the cover tape is JIS Z 0208.
1.5 g / m ² · 24 measured at 40 ° C. and 90% RH
hr or less, preferably 0.7 g / m ² · 24
hr or less is good. If it exceeds 1.5 g / m ² · 24 hr, the function of preventing cracks in the sealing resin at the time of solder mounting is insufficient, and protection / storage by packaging in a moisture-proof bag or re-baking in a later process is required. Required.

[0010]

EXAMPLES Examples of the present invention are shown below, but the present invention is not limited by these examples. << Examples 1 , 2 , 3 , 4 , 5 , 6 , 7 and Comparative Example A,
B, >> The first layer 2 made of a biaxially stretched film and the moisture-proof layer 3 having a thickness of 15 μm made of a metal layer having excellent moisture-proof properties are bonded by dry lamination with a two-part thermosetting urethane-based adhesive, and then A heat-seal lacquer adhesive was formed to a thickness of 2 μm on the moisture-proof layer side of the film with a gravure coater and slit to a width of 21.5 mm to obtain a cover tape having a layer structure shown in Table 1. Next, 10 μm in the layer configuration shown in FIG.
A total thickness of 260 μm of a three-layer structure in which an m-thick Al foil sheet is sandwiched from both sides with a 125 μm-thick PVC sheet
The m composite sheet for carrier tape was embossed by a pressure molding machine to obtain a carrier tape having a width of 24 mm. or,
The moisture permeability of the composite sheet is determined according to JIS Z 0208 method 40
C., 90% RH. Next, the electronic component QFP
52P was housed in an emboss and sealed with the cover tape. After the sample was put in a 30 ° C., 70% RH environment for 60 days, the cover tape was peeled off and the change in weight of the sealing resin of the electronic component due to moisture absorption was measured to calculate the moisture absorption rate. Next, the extracted electronic component is subjected to IR reflow (2
(40 ° C., 10 seconds) and the presence or absence of cracks was observed by an engineering microscope (× 100), and various evaluation results are shown in Table 1.

[0011]

[Table 1]

Note 1: The raw material names of the resins used are as follows. PET: Espet film (amorphous) manufactured by Toyobo Co., Ltd. NY: Harden film manufactured by Toyobo Co., Ltd. PP: Pyrene film manufactured by Toyobo Co., Ltd. Note 2: The moisture permeability of the composite sheet before molding is JIS Z in the state
The measurement was performed at 40 ° C. and 90% RH. Note 3: Moisture absorption after sealing in carrier tape, 30 ℃, 7
0% RH, QFP in carrier tape treated for 60 days
Calculated from the weight change of 52P (14 mm x 14 mm x 2 mmt). Note 4: Cracks were evaluated by soldering electronic components taken out of the carrier tape and observing the surface of the sealing resin.

[0013]

According to the present invention, the electronic components housed in the carrier tape do not absorb moisture during transportation and storage of the electronic components without being repackaged by a dry pack in a later process, and can be used during the mounting process. There is no need for re-baking, and the occurrence of cracks in the sealing resin in the soldering process can be prevented. At the same time, the dry pack packaging step and the re-baking step can be omitted, and the number of steps can be significantly reduced.

[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 an example of a layer structure of a carrier tape for sealing a cover tape of the present invention.

Claims (1)

(57) [Claims] 1. A cover tape which can be sealed on a plastic embossed carrier tape in which storage pockets for storing chip-type electronic components are formed continuously, wherein at least one of Al, Cu, Zn, Sn, Ni, Ti, A composite sheet having two or more layers having a metal layer made of either Si or a compound thereof, wherein the moisture permeability of the composite sheet is JIS.
Z 0208 40 ° C., 90% RH.
A cover tape for packaging a chip-type electronic component having a weight of 5 g / m ² · 24 hr or less.