JP2000079942A - Boggie for electronic parts container and method for preventing electrical charge of electronic parts under application of boggie - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a positive protection of electronic parts against static electricity by releasing the static electricity to a floor through an electrical conductor. SOLUTION: This boggie 11 for electronic parts container is comprised of a frame 12 and some casters 13. On the upper surface of the frame 12 is mounted an electrical conductor container 1 capable of storing electronic parts 2. There are provided a plurality of casters 13 which are fixed to the frame 12. This boggie 11 is provided with an earth structure capable of releasing static electricity through a tape 14 of electrical conductor and a chain 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trolley for electronic component containers and a method for preventing electrification of electronic components using the same.

[0002]

2. Description of the Related Art A printed wiring board on which various components such as a semiconductor chip have been mounted is subjected to a predetermined inspection process and then shipped as a final product. Usually, this type of printed wiring board is transported to the next step in a state where a plurality of printed wiring boards are accommodated in a box called a container.

If a worker carrying a printed wiring board is charged with static electricity, for example, if the worker touches the printed wiring board carelessly, a semiconductor chip or the like that is weak to static electricity is electrically destroyed. Sometimes. Therefore, in recent years, antistatic measures have been taken to use a so-called conductive container.

[0004]

However, even if the container itself is provided with conductivity, the frame and casters of the bogie are generally made of a resin having extremely low conductivity.
Eventually, it is difficult for static electricity to come off, and it tends to remain accumulated. Therefore, at present, it has been difficult to say that sufficient antistatic measures have been taken.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an electronic component container trolley capable of reliably protecting electronic components from static electricity and an antistatic method using the same. Is to do.

[0006]

According to the first aspect of the present invention, a plurality of casters are mounted on a frame on which a conductive container capable of housing electronic components is mounted. The gist of the present invention is a cart for an electronic component container, which is provided with a grounding structure capable of releasing static electricity to the floor via a conductor.

According to a second aspect of the present invention, in the first aspect, the grounding structure is provided on an upper surface side of the frame and is in contact with a bottom surface of the conductive container. The second conductor is connected to a part of the first conductor and has a length such that the other end reaches the floor surface.

According to a third aspect of the present invention, there is provided a method for preventing electrification of an electronic component using the electronic component container trolley according to the first or second aspect, wherein a conductive area is previously provided at a predetermined position in the transport path of the trolley. Together with
When the carriage passes over its conductive area during transport,
A gist of the present invention is a method for preventing static charge of an electronic component, characterized by discharging static electricity to the conductive area via the grounding structure.

Hereinafter, the "action" of the present invention will be described. According to the first aspect of the present invention, static electricity is released to the floor via the conductor, so that static electricity does not remain in the container, and sufficient antistatic measures can be taken. Therefore, the electronic component is reliably protected from static electricity, and its electrical destruction can be reliably prevented.

According to the second aspect of the present invention, since the other end of the second conductor has a length that reaches the floor, the first and second conductors are provided between the container and the floor. A conductive path consisting of a body is created. Therefore, the static electricity accumulated in the container moves to the first conductor side that is in contact with the bottom surface of the container, and then further moves to the second conductor side, and is finally released to the floor surface. .

The operation of the present invention will be described. Generally, static electricity often occurs due to rubbing of clothes when an operator moves. Therefore, when the container is placed on the carriage and transported, static electricity is more likely to occur as compared to when the container is stopped. Therefore, if the carriage passes over the conductive area during transportation, static electricity can be reliably released through the grounding structure when passing through the conductive area. Therefore, static electricity does not remain in the container, and sufficient antistatic measures can be taken.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electronic component container trolley 11 according to an embodiment of the present invention will be described below in detail with reference to FIGS.

As shown in FIG. 1, the electronic component container used here is a so-called conductive container 1. As a forming material, the resistivity is 10
^{0 Ωcm~10 6 Ωcm} resin material is used.
Specifically, here, the surface specific resistivity is 10 ⁶ Ωc
m and a volume resistivity of 10 ³ Ωcm or less
P (conductive polypropylene) is used. Conductive PP
The term refers to a material in which carbon, which is conductive particles, is dispersed in propylene, which is a matrix. Incidentally, conventional insulating products have a surface resistivity of 10 ¹⁴ Ω.
A resin material of 10 cm to 10 ¹⁸ Ωcm is used.

The conductive container 1 according to the present embodiment accommodates a printed wiring board (a so-called chip module) 2 on which semiconductor chips and various components are already mounted. The printed wiring board 2 generally has a rectangular shape, and various conductive patterns 7 and 8 are formed on one or both surfaces thereof (see FIG. 5). These conductor patterns 7 and 8 are covered with a solder resist 9. In the case of a double-sided board or a multilayer board, a through hole 10 for electrically connecting the conductor patterns 7 and 8 on both front and back sides is further formed.

As shown in FIGS. 1 and 2, the conductive container 1 has a box shape with a bottom. Conductive container 1
The upper part is a rectangular opening. A pair of partitions 3 are provided inside the conductive container 1.
Each partition 3 is constituted by assembling two long rods 4 and many short rods 5.

The long rods 4 have a length substantially equal to the long side of the conductive container 1 and are arranged in parallel with each other and up and down along the longitudinal direction of the conductive container 1. The short bar 5 has a length corresponding to the depth of the conductive container 1 and is fixed vertically to the pair of long bars 4. The short bar members 5 are fixed with a space slightly larger than the thickness of the printed wiring board 2 to be accommodated.

On the inner side surface of the conductive container 1, a number of ribs 6 for partitioning and fixing are integrally provided. These ribs 6 extend along the height direction of the conductive container 1 and are equally spaced from each other. Both ends of the long bar 4 constituting the partition 3 are inserted into gaps formed by these ribs 6. As a result, the positioning and fixing of the partition 3 in the conductive container 1 is achieved.
At this time, the distance between the pair of partitions 3 can be adjusted according to the external dimensions of the printed wiring board 2 to be accommodated. The long bar 4 is made of a conductive metal such as aluminum, and the short bar 5 is made of a conductive resin such as the conductive PP.

As shown in FIG. 2, each printed wiring board 2 is arranged so as to stand substantially vertically in a gap formed by a pair of partitions 3. At this time, the outer peripheral surface of the short bar 5 can come into contact with the outer edge of the printed wiring board 2. As a result, the printed wiring boards 2 are held in a state where they do not come into surface contact with each other during the accommodation.

At this time, for example, it is preferable to make it as shown in FIG. That is, when there is a conductor pattern (ground pattern) 8 at the outer edge of the printed wiring board 2, a predetermined portion of the solder resist 9 is peeled off to expose a part of the ground pattern 8. Then, the short bar 5 is brought into contact with the exposed conductive portion. In this way, the static electricity in the printed wiring board 2 can be reliably released to the conductive container 1 via the route of the ground pattern 8 → the short bar 5 → the long bar 4 → the rib 6.

Next, the configuration of the electronic component container cart 11 of the present embodiment having a grounding structure will be described. As shown in FIGS. 1 and 3, the frame 12 constituting the carriage 11 has a rectangular shape like the conductive container 1. Substantially L-shaped positioning projections are provided at four corners on the upper surface of the frame 12, respectively. The frame 12 of the present embodiment is a molded product made of a general resin material having no conductivity. On the upper surface of such a frame 12, the bottom surface of the conductive container 1 is placed.

At four corners on the lower surface side of the frame 12, casters 13 are attached using bolts or the like. Each of the four casters 13 has a structure in which a tire is rotatably supported between a pair of bearing pieces via a shaft. Usually, while the bearing piece and the shaft are made of conductive metal such as stainless steel,
The tire that directly contacts the floor 18 is made of resin or rubber (that is, made of insulator). Therefore, these casters 13 do not conduct electricity when viewed as a whole.

As shown in FIG. 1 and FIG.
1 has a grounding structure composed of the following two types of conductors. A conductive metal tape 14 as a first conductor is attached to the upper surface of the frame 12. Such a tape 14 is provided with an adhesive layer on one side of a conductive metal layer, and is attached over the entire periphery of the upper surface of the frame 12. When placing the conductive container 1,
The surface of the tape 14 comes into contact with the bottom surface of the conductive container 1. In this embodiment, specifically, a copper tape having a width of about 1 cm to 2 cm is used. Of course, conductive metal materials other than copper (for example, aluminum, iron, iron alloys such as stainless steel, nickel, cobalt,
A tape using silver or the like may be used.

As shown in FIG. 4, a chain 15 made of a conductive metal as a second conductor is provided using a screw 16 at the center of the rear end of the upper surface of the frame 12. One end of the chain 15 is connected to a part of the tape 14. The other end of the chain 15 hangs down by its own weight and reaches the floor 18. Therefore, the chain 15 is always in sliding contact with the floor surface 18 when the carriage 11 is run. In this embodiment, specifically, a copper chain having a length of about 5 cm to 10 cm is used. Of course, a chain using a conductive metal material other than copper (for example, an iron alloy such as aluminum, iron, and stainless steel, nickel, cobalt, and silver) may be used.

Next, a description will be given of an antistatic method in the case where the truck 11 configured as described above is used. On the carriage 11, the conductive container 1 in which the printed wiring board 2 is stored in advance is placed. At this time, FIG.
, Conductive containers 1 of the same standard may be stacked in a plurality of stages. Further, for the conductive container 1 located at the uppermost stage, a lid (not shown) also made of conductive PP
May be covered.

Assuming that there is a transport path for the carriage 11 on the floor surface 18, the electrostatic mat 17 is laid beforehand on a predetermined portion of the transport path (for example, on the floor near the entrance or the exit). Electrostatic mat 1 as conductive area
Reference numeral 7 denotes a sheet-like resin material having a thickness of several mm through which electricity can pass to some extent, and is grounded. Such a thing is sometimes called a "station".

After completing the previous process, the operator moves the carriage 11 along the transport path. The cart 11 always passes over the electrostatic mat 17 in this case because the electrostatic mat 17 exists on the transport path. Then, when passing through the electrostatic mat 17, the tip of the hanging chain 15 slidably contacts the surface of the electrostatic mat 17 as shown in FIG. As a result, the tape 14 and the chain 15 provide a conductive path between the conductive container 1 and the floor 18.
Therefore, the static electricity accumulated in the conductive container 1 first moves to the conductive metal tape 14 side, and further moves to the conductive metal chain 15 side. Finally, the static electricity is surely released to the electrostatic mat 17 on the floor 18.

Therefore, according to the present embodiment, the following effects can be obtained. (1) The cart 11 has a grounding structure capable of releasing static electricity to the floor 18 via a conductor. When such a grounding structure is provided, static electricity does not remain in the conductive container 1 and sufficient antistatic measures can be taken. Therefore, the printed wiring board 2 is reliably protected from static electricity, and electrical destruction of the mounted semiconductor chip or the like can be reliably prevented.

(2) The grounding structure of the cart 11 is as follows:
It is composed of a conductive metal tape 14 as a first conductor and a conductive metal chain 15 as a second conductor connected to a part of the tape 14. Therefore, by retrofitting the configuration of the tape 14 and the chain 15 on the basis of the existing cart, it can be manufactured very easily.

(3) In the grounding structure of the cart 11, a conductive metal tape 14 is used as a first conductor. This kind of tape 14 is suitable for cost reduction because the material itself is inexpensive, and can be provided very easily on the upper surface of the frame 12 by bonding. Here, a conductive metal chain 15 is used as the second conductor. Since this kind of chain 15 is also a relatively inexpensive material, it is suitable for cost reduction. In addition, the chain 15 has a property of hanging down by its own weight, so that the chain 15 can reliably follow and contact the floor surface 18 regardless of the presence or absence of unevenness. That is, sufficient antistatic measures can be taken despite low cost and easy manufacture.

(4) In this embodiment, a pair of partitions 3 having conductivity are used, and the ground pattern 8 of the printed wiring board 2 comes into contact with the partitions 3 during storage. . Therefore, the static electricity in the printed wiring board 2 can be surely released to the conductive container 1 side, and more suitable antistatic measures can be taken.

(5) Further, according to the antistatic method of the present embodiment, the electrostatic mat 17 is laid beforehand at a predetermined position on the transport route of the carriage 11. Therefore, even if static electricity is generated due to rubbing of clothes of a worker performing a transport operation, the static electricity is transferred to the electrostatic mat 1.
7 can be reliably released when passing through.

The embodiment of the present invention may be modified as follows. -In the said embodiment, the printed wiring board 2 in the state where the semiconductor chip etc. were already mounted was mentioned as an example of the electronic component which is an accommodation object. The present invention is, of course, not limited to this, and may be applied to a case where a semiconductor package represented by, for example, PGA, BGA, or the like is used as an object.

The conductive metal tape 14 does not necessarily have to be adhered over the entire periphery of the frame 12 and may be partial. Further, the chains 15 may be provided at a plurality of positions on the carriage 11.

It is also possible to use a material other than the conductive metal tape 14 as the first conductor. For example, there are a method of attaching a metal plate material to the upper surface of the frame 12, plating the same surface, and printing a conductor layer on the same surface.

It is also possible to use a material other than the conductive metal chain 15, for example, a rod or brush made of a conductive metal as the second conductor. Not only the grounding structure is realized using two types of conductors as in the embodiment, but also the grounding structure can be realized using only one type of conductor. For example, the chain 15 as the second conductor may be provided at the position where the tape 14 was in the first embodiment.

In the embodiment, the ground pattern 8 exposed by peeling the solder resist 9 is in contact with the short bar 5. In addition, the short bar 5 may be brought into contact with a portion electrically connected to the ground pattern 8 (for example, an existing plated through hole or a metal case of a mounted component). Of course, the partition 3 may be configured to be in non-contact with these specific conductor portions.

The frame 1 which is a component of the cart 11
It is also acceptable that the 2 itself is made of a conductive material such as a conductive PP or the like. Thus, in this case chain 15
May be connected to a part of the frame 12 and the other end may reach the floor 18. With such a grounding structure, charging can be prevented in a state where the tape 14 is omitted.

One or more of the casters 13, which are components of the carriage 11, may be formed of a conductive material such as conductive PP. Can be achieved.

In place of the method of laying the electrostatic mat 17, for example, a method of sticking a conductive metal tape to the floor 18 near the entrance may be adopted.

Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the above-described embodiments will be listed below together with their effects. (1) In claim 2, the second conductor is a conductive metal chain (preferably a copper chain or the like). Therefore, according to the invention described in the technical idea 1, the chain is a relatively inexpensive material, which is suitable for cost reduction. In addition, the chain has the property of hanging under its own weight,
Irrespective of the presence or absence of unevenness, it can reliably follow and contact the floor surface.

(2) In the technical idea 1, the first conductor is a conductive metal tape (preferably a copper tape or the like). Therefore, this technical idea 2
According to the invention described in (1), the material itself is inexpensive, so that it is suitable for cost reduction. In addition, it can be extremely easily provided on the upper surface of the frame by bonding.

(3) In the technical concept 2, the conductive metal tape is adhered over substantially the entire upper surface of the frame. Therefore, according to the invention described in the technical idea 3, as a result of securing a relatively large contact area between the conductor on the top surface of the frame and the bottom surface of the container,
Static electricity can be more reliably released.

(4) In claim 1, the grounding structure comprises a frame formed by using a conductive material and a caster formed by using a conductive material. (5) The grounding means according to (1), wherein the grounding means is made of a conductive metal and a frame formed by using a conductive material, and having one end connected to a part of the frame and the other end reaching the floor. Consisting of a chain of

(6) In claim 3, the partition in the conductive container has conductivity. (7) In claim 3, the partition in the conductive container has conductivity, and a specific conductor portion of the electronic component can contact the partition when the electronic component is accommodated. thing. Therefore, according to the invention described in the technical concept 7, further reliable antistatic measures can be taken.

(8) In the technical idea 7, the electronic component is a printed wiring board after component mounting, and the specific conductor portion in the electronic component is a ground pattern of the printed wiring board or an electrical component connected to the ground pattern. It must be a place that is electrically connected to

(9) In Claim 3, the conductive area is an electrostatic mat (so-called station) laid on the floor.

[0047]

As described above in detail, according to the first and second aspects of the present invention, it is possible to provide a cart for an electronic component container capable of reliably protecting electronic components from static electricity.

According to the third aspect of the present invention, it is possible to provide an antistatic method capable of reliably protecting an electronic component from static electricity.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an electronic component container according to an embodiment of the present invention and a method of using a cart for the electronic component container.

FIG. 2 is a plan view showing a state where a printed wiring board is housed in an electronic component container.

FIG. 3 is a plan view of the truck for electronic component containers according to the embodiment.

FIG. 4 is an essential part enlarged sectional view showing a use state of the cart for electronic component containers according to the embodiment.

FIG. 5 is an enlarged sectional view of a main part showing a state inside the electronic component container.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Conductive container, 2 ... Printed wiring board (chip module) as an electronic component, 11 ... Truck for electronic component containers, 12 ... Frame, 13 ... Casters, 14 ... First conductor which is a part of grounding structure A conductive metal tape as a second conductor which is a part of a grounding structure; 15 an electrostatic mat as a conductive area;
18 ... floor surface.

Claims (3)

[Claims] 1. A trolley comprising a plurality of casters mounted on a frame on which a conductive container capable of housing electronic components is mounted, the trolley having a grounding structure capable of releasing static electricity to a floor via a conductor. A trolley for electronic component containers. A first grounding structure provided on an upper surface side of the frame and in contact with a bottom surface of the conductive container;
And a second conductor having one end connected to a part of the first conductor and the other end reaching the floor. Cart for electronic component containers. 3. A method for preventing electrification of an electronic component using the cart for an electronic component container according to claim 1 or 2, wherein a conductive area is provided in a predetermined place in a conveying route of the cart, and the conveying is performed. An antistatic method for an electronic component, comprising: discharging static electricity to the conductive area via the grounding structure when the carriage passes over the conductive area.