JPS60126899A - Electrostatic shielding bag - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of the Invention] The present invention relates to a static electricity shielding bag, particularly a static electricity shielding bag for transporting printed circuit boards mounted with integrated circuit elements. Accordingly, semiconductor integrated circuit elements are becoming more densely packed using fine patterns. However, on the other hand, damage to the inside of the element due to overvoltage, especially static electricity generated in the surroundings while handling the circuit element, becomes noticeable, and attempts to protect the element with the circuit structure inside the element result in a deterioration in performance. In the end, consideration must be given to prevent static electricity from being applied to the device during handling. Furthermore, this trend is becoming more and more important as density increases.

Conventionally, as a countermeasure of this type, printed circuit boards that are being assembled or assembled are placed in conductive bags, and care is taken during handling, storage, and shipping within the factory. The sheet material of this typical bag is transparent (light transmittance is not necessarily 1001) so that the contents can be seen without removing each printed circuit board from the bag.
%), the outer sheath has a low surface resistance to prevent external electric fields from penetrating inside, and the middle layer uses a high insulator to block the rut current flowing on the outside from penetrating into the circular part, and In order to discharge static electricity generated by friction between the bags, this surface also has a low surface resistance. Furthermore, due to the convenience of manufacturing the bag, the material for the inner cover of this sheet is a film that can be bonded by heat (heat rail), and has a multilayer structure as a whole. Therefore, in order to maintain transparency and obtain conductivity on the inner and outer surfaces, this conductive film is not necessarily strong and is often used multiple times to compensate for the decrease in conductivity. If used without knowing this, it is easy to damage the semiconductor integrated device. Therefore, the repeated use has drawbacks such as the need to check the conductivity performance with a measuring instrument from time to time.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks and provide a static electricity shielding bag that allows the degree of deterioration of static electricity shielding performance to be visually determined.

[Summary of the invention]

The structure of the present invention is that, in an electrostatic shielding bag made of a transparent sheet having a multilayer structure including a conductive layer, single pieces of pressure-sensitive recording paper are sandwiched between the multilayer structure at intervals that allow the inside to be confirmed from the surface. 0 [Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an external view of an embodiment of the present invention, in which a transparent sheet 1 consisting of a multilayer structure including a conductive layer and holding a single piece of pressure-sensitive recording paper is folded in half, and both sides 2 are heat-sealed. It was glued together and made into a bag.

Figure 2 is a perspective view showing the cross section of the transparent sheet used in Wc1, and shows the antistatic polyethylene film 3.
The inner cover of the TF bag is made by mixing Ansunt additives with polyethylene, and has a surface resistance of 1:1! Ω
/ Mouth It has electrical conductivity at the front and back, and constantly discharges static electricity generated by friction between the inside of the bag and the printed circuit board, suppressing the generation of voltage. The outer sheath of the bag is made of a polyester film 5 with a metal coating 4 deposited on it, so that the electric field of a charged human body, etc., which reaches several thousand volts, does not penetrate into the inside of the bag, and under normal conditions, the bag instantly closes. In order to make the surface equipotential, a surface resistance of 100/min or less is desired. For this reason, the vapor-deposited film is made at about 100 A under conditions that allow the inside to be seen. On the other hand, the polyester film 5 is made of a highly insulating material and prevents the electric current on the vapor-deposited film from penetrating into the interior. Single pieces of pressure-sensitive recording paper cut into five fins are clamped at intervals of about IQgm between the polyethylene film 3 constituting the inner cover and the polyester film constituting the outer cover. This single-piece pressure-sensitive recording paper is coated with color former-containing microcapsules and a color developer in a layered or mixed manner on one side of the paper, and can produce color with just one sheet.

The new bag shown in Figure 1 made of the transparent sheet described above completely protects the integrated circuit elements of the printed circuit board placed inside from static electricity, but if this bag is used multiple times in a factory etc., it will bend each time it is handled. ), visible scratches, etc.
Cracks occur in the conductive coating on the circular and outer surfaces, increasing the resistance and eventually losing the electrostatic shielding effect. However, at the same time, the single pressure-sensitive recording paper clamped to the transparent sheet was also exposed to pressure and a brocade-like color development was observed. Therefore, it is advisable to prepare a sample of the color development for the limit of the resistance value measured with a measuring device in advance, and it is possible to judge whether it is good or bad by simply observing the color development state without using a measuring device each time.0 [Advantages of the Invention] As described above in detail, the present invention has the advantage that it can provide an electrostatic shielding bag that can visually determine whether or not it can be used.

[Brief explanation of the drawing]

FIG. 1 is an external view of one embodiment of the present invention, and FIG. 2 is a perspective view including a cross section of the transparent sheet used in FIG. 1. DESCRIPTION OF SYMBOLS 1... Transparent sheet, 2... Side adhesive part, 3... Inner coating polyethylene film, 4...
...Metal vapor deposition film, 5.. Polyester film, 6. Old.. Single piece of pressure-sensitive recording paper.

Claims (1)

[Claims] A static electricity shielding bag made of a transparent sheet with a multilayer structure containing a conductive layer, in which single pieces of pressure-sensitive recording paper are glued to the middle of the multilayer structure at intervals that allow the inside to be seen from the surface. shielding bag.