JPS63272542A - Sheet for packaging electronic parts - Google Patents

Abstract

PURPOSE:To prevent electronic parts from static breakage for a long period of time by specifying the thickness of conductive layer, surface resistance, beam permeability, surface resistance of plastic provided on both sides of the conductive layer, moisture pearmeability of a gas barrier layer and oxygen permeability respectively. CONSTITUTION:An insulated layer 2 constituting at least the inner surface is of heat sealability, and the surface resistance of insulated layers 2 and 3 constituting the inner and outer surfaces is made to be 10<5>OMEGA/square or more and 10<13>OMEGA/square or less. As the insulated layer 2, plastic films bonded together or coating of synthetic resin coating material is effective. A gas barrier layer 4 is provided on the outside or both sides of a conductive layer 1 constituted of Al or Cu. For the purpose of securing static sealing effect, the surface resistance of the conductive layer 1 is set to be 10<4>OMEGA/square or less, and its beam permeability is set to be 30 % or more and the thickness is set to be 40-150Angstrom so as not to disturb confirming the packaged content visually with ease. For the transparent gas barrier layer 4, polyvinylidene chloride or the like is used, and its moisture permeability should be set to be 3 g/m<2>.24 h or less, while oxygen permeability is set to be 3 ml/m<2>.24 h.atm or less.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a sheet for packaging electronic parts.

[Prior Art] Electronic components are becoming highly integrated, as seen in LSIs, etc., and are progressing in the direction of becoming extremely vulnerable to electrostatic damage. Therefore, in order to prevent electrostatic damage during transportation/storage of electronic components, sheets for packaging electronic components as described in Japanese Patent Publication No. 80-18294 have been proposed. This electronic component packaging sheet is made of a transparent electrically insulating polymer sheet with heat-sealability, and has a conductive layer with a surface resistance of 104Ω/□ on the outer surface, and a surface resistance of 108Ω/□ on the inner surface. Antistatic treatment has been applied to achieve a resistance of □ to 10'Ω/□.

When packaging electronic components using the above-mentioned conventional electronic component packaging sheet, the sheet is transparent, so the electronic components contained in the package can be seen through, and the sheet has heat-sealing properties, so it can be bonded and sealed. Easy to work with.

In addition, since the inner surface of the sheet is treated with antistatic treatment, the sheet itself is non-static and does not generate static electricity, and even if it comes into contact with electronic components, it will not cause electrostatic damage to the electronic components. do not have.

Furthermore, since the outer surface of the sheet is provided with a conductive layer, the space within the sheet surrounded by the conductive layer is electrostatically shielded and is not affected by external electrostatic fields at all, thereby protecting electronic components from electrostatic damage.

[Problems to be Solved by the Invention] However, in the conventional electronic component packaging sheet described above, the conductive layer is exposed on the outer surface of the sheet. Therefore, there is a possibility that an electronic component approaches/contacts a conductive layer with a low surface resistance during encapsulation or unpacking of the electronic component, and at this time, if there is a potential difference, even a small potential difference, between the electronic component and the conductive layer. A large current flows between the two, causing spark discharge and electrostatic damage to electronic components.

In addition, when packaging electronic components using the conventional electronic component packaging sheet described above, the working environment is set in a state that does not generate static electricity and high voltage (several KV) is applied.
Although it is extremely unlikely that a person who is electrically charged will carry out packaging work, it is impossible to keep the packaging constantly grounded, which causes an accumulation of charges in the conductive layer on one surface. This creates a potential difference between the electronic component and the conductive layer that causes the spark discharge.

Further, when implementing the above-mentioned conventional electronic component packaging film, N1 electron beam deposition is suitable for the conductive layer, but this is more expensive than AI or Cu deposition. However, when vapor-deposited films of AI or Cu are used, these thin metal layers gradually react with oxygen and water vapor in the air, forming oxides and hydroxides, which lose their conductivity and protect electronic components from static electricity. The function to protect (electrostatic shielding) is also lost. Therefore, the above-described vapor deposited film such as Cu or Cu cannot be used.

The present invention provides a packaging sheet that allows electronic components as packaged contents to be seen through, has low bonding and sealing workability, and reliably protects electronic components from electrostatic damage over a long period of time with high reliability. The purpose is to

[Means for Solving the Problems] The present invention provides a sheet for packaging electronic components, in which both sides of a conductive layer are covered with transparent plastic, and a gas barrier layer is provided on one or both sides of the conductive layer. , the conductive layer has a thickness of 40 to 150 Å, a surface resistance of 10'Ω/□ or less,
and the light transmittance is 30% or more, the surface resistance of the plastic provided on both sides of the conductive layer is 105Ω/□ or more and 1o13Ω/□ or less, and the plastic provided on at least the other outermost layer of the conductive layer is heat-sealed. The gas barrier layer has a moisture permeability of 3g/+2.24h or less and an oxygen permeability of 3g/+2.24h-atm or less.

[Function] The electronic component packaging sheet according to the present invention is schematically shown in FIGS. 1(A) and 1(B), where 1 is a conductive layer, 2 is an insulating layer (inner surface film), and 3 is an insulating layer. Layer (outer film)
, 4 is a gas barrier layer. Note that another layer may be present between the conductive layer 1 and the gas barrier layer 4. According to the present invention, the following effects are achieved.

(2) Since the insulating layer constituting the sheet is transparent and the light transmittance of the conductive layer is 30% or more, electronic components as packaged contents can be seen through.

(2) The insulating layer constituting at least the inner surface of the sheet has heat-sealing properties, so the bonding and sealing workability is good.

■The surface resistance of the insulating layer that makes up the inner and outer surfaces of the sheet is 105
Since Ω/□ or more and 1013 Ω/□ or less, these insulating layers themselves become non-static and do not generate static electricity.
Even if it comes into contact with an electronic component, it will not cause electrostatic damage to the electronic component.

■Since the sheet has a conductive layer inside, the space inside the sheet surrounded by the conductive layer is electrostatically shielded and is completely unaffected by external electrostatic fields, protecting electronic components from electrostatic damage.

(Φ(ΦEven if the electric charge of a charged body such as a human body moves/accumulates on the insulating layer that constitutes the outer surface of the sheet, the surface resistance of the outer surface of the bag is 1.
Since it is high at 05 Ω/□ or more, the charge accumulated in the outer surface infusible layer does not cause spark discharge between the electronic component and the electronic component when the electronic component is sealed or unsealed. ■The electric charge accumulated in the outer insulating layer in the above step (■) does not move/accumulate in the conductive layer because the volume resistivity of the insulating layer is high, causing spark discharge from the conductive layer to the electronic components. Nor.

■Since there is a gas barrier layer on the outside or both sides of the conductive layer, it protects thin metal layers such as Al and Cu that easily form oxides and hydroxides from oxygen and water vapor, and maintains conductivity over a long period of time. . As a result, even when electronic components are used for long-term storage, the electrostatic shielding property does not deteriorate, and the electronic components as packaged contents can be protected from rust and corrosion.

Note that films with heat sealability include polyethylene and ethylene/vinyl acetate copolymers.

Furthermore, as the insulating layer, bonding of plastic films or coating with synthetic resin paint are effective and easy methods. In order to prevent spark discharge, the higher the volume resistivity and the thicker the insulating layer, the greater the prevention effect.

The lower limit of resistance required to prevent spark discharge is the surface resistance value of the insulating layer after covering the conductive layer with the insulating layer (in the final product stage), which is 10 5 Ω/□ or more.

In addition, as an antistatic treatment for the insulating layer, an antistatic agent [surfactant, conductive fine powder (carbon, metal, metal oxide), conductive fiber (carbon, metal)] may be added to the insulating layer. Antistatic coating on the surface of the insulating layer (surfactant, polysiloxane, ion conductive polymer, carbon
It is effective to apply a paint containing dispersed metals, metal oxides, etc. The upper limit value of resistance necessary for preventing static electricity is the surface resistance value of the insulating layer at the final product stage of 10 13 Ω/□ or less. Note that particularly effective antistatic treatment methods include combination of surfactants and antistatic coating. The method of blending conductive fine powder or conductive am into the insulating layer is effective on the condition that the surface resistance value of the insulating layer in the final product stage is maintained at 10 5 Ω/□ or more.

Furthermore, since the electrostatic shielding property is determined by the resistance value of the conductive layer, it is not affected by the insulating layer.

Further, in order to ensure an effective electrostatic shielding effect, the conductive layer must have a surface resistance of 10 4 Ω/□ or less.

Further, the light transmittance of the conductive layer must be set to 30% or more so as not to hinder easy visual confirmation of the contents of the package.

Also. If the thickness of the conductive layer is less than 40 Ω, its surface resistance will exceed 10'Ω/□, and if the thickness exceeds 15 OA, its light transmittance will be less than 30%.

Therefore, the thickness of the conductive layer must be set to 40-150.

Note that polyvinylidene chloride (PVDC), ethylene-vinyl alcohol copolymer, etc. can be used as the transparent gas barrier layer.

Furthermore, the lower the moisture permeability and oxygen permeability of the gas barrier layer, the longer the period during which the bag can maintain its antistatic performance. Therefore, it is difficult to limit the range of moisture permeability and oxygen permeability, but as in the present invention, the moisture permeability can be reduced to 3g/■2.
4 hours or less, oxygen permeability 3mJ1/+++2・2
If the temperature is 4h-at■ or less, the temperature is 85℃ as described below.
Since no change occurred in the electrostatic shielding effect or light transmittance after 720 hours at 85% RH, it is thought that it can withstand long-term storage.

[Example] Example (see FIG. 2(A)) On one side of a polyester film (PET) 11 with a thickness of 25 tiles, a 100-layer A-deposited film 12 was formed as a conductive layer by vacuum deposition. The light transmittance of this film is about 40%, and the surface resistance of the A-type film is 1×102Ω1.
Next, polyvinylidene chloride (PVDC) 13 was coated on the An evaporated surface of this film.
Axial oriented polypropylene film (OFF) 14 pvo
After the c-coated surfaces were bonded together, a polyethylene film 15 containing an antistatic agent was bonded to the opposite surface (A unstained surface of the polyester film 11).

With the polyethylene film side of this film inside,
The packaging was created by heat sealing.

Comparative example (see Figure 2 (B)) A4 vapor deposition of Example! After bonding the PVDC-coated side of the polyester film 22 coated with polyvinylidene chloride (PV[)C) 21 to one side of the polyester film 11 that formed J12 after the AIL vapor deposition, the PVDC-coated side of the polyester film 22: not coated. A polyethylene film 15 containing an antistatic agent was attached to the surface. A package was created by heat sealing this film with the polyethylene film side inside.

For each of the above examples and comparative examples, the electrostatic shielding effect and light transmittance were measured.Next, the opening of the bag was heat-sealed without putting anything in the bag, and the bag was placed in an environment of 85°C x 85% RH for 720 hours. The electrostatic shielding effect and light transmittance after aging were measured.

In addition, the outer layer of the conductive layer (Example: pvoc coat O
The moisture permeability and oxygen permeability of PP, comparative example: PET) were also measured. The measurement results are shown in Table 1.

According to Table 1, the following is recognized. In the example, the electrostatic shielding effect did not change after aging, but
In the comparative example, the electrostatic shielding effect after aging is significantly reduced. Deterioration of the thin metal layer can also be confirmed by light transmittance. After aging, the comparative example lost its metallic luster and its light transmittance increased.

In addition, in the sheet of the above example, ■the outer surface resistance is 1
If the surface resistance is 0'Ω/□ or more, the surface discharge current is small. ■ If the outer surface resistance is 1013Ω/□ or less, the frictional charging voltage is small. ■ Since the electrostatic shielding property is provided by the conductive layer, the outer surface It was confirmed that this was not related to resistance.

[Effects of the Invention] As described above, according to the sheet for packaging electronic components of the present invention, the electronic components as packaged contents can be seen through, the bonding and sealing workability is good, and the reliability of the electronic components is maintained over a long period of time. can reliably protect against electrostatic damage.

[Brief explanation of drawings]

Figures 1 (A) and (B) are schematic diagrams showing the basic structure of the present invention, Figure 2 (A) is a schematic diagram showing an embodiment, and Figure 2 (B)
is a schematic diagram showing a comparative example. l, 12... Conductive layer, 2.3.14.15... Insulating layer, 4.13... Gas barrier layer. Patent applicant Sekisui Chemical Co., Ltd. Representative Hiroshi 1) Kaoru Figure 1 (A) (A) (B) (B)

Claims (3)

[Claims] (1) A sheet for packaging electronic components in which both sides of a conductive layer are covered with transparent plastic and a gas barrier layer is provided on one or both sides of the conductive layer, the conductive layer having a thickness of 40 to 150 Å and a surface The resistance is 10^4Ω/□ or less, and the light transmittance is 30% or more, and the surface resistance of the plastic provided on both sides of the conductive layer is 10^5Ω/□ or more and 10^1^3Ω/□ or less, and it is conductive. The plastic provided on the outermost layer on at least the other side of the layer has heat sealability, and the gas barrier layer has a moisture permeability of 3 g/m^2.24.
h or less, and the oxygen permeability is 3ml/m^2・24h・
A sheet for packaging electronic parts that is below ATM. (2) The electronic component packaging sheet according to claim 1, wherein the conductive layer is made of Al or Cu. (3) The sheet for packaging electronic components according to claim 1, wherein the gas barrier layer is made of polyvinylidene chloride resin.