Abstract:
A method of transporting PLCC IC packages (3) having J-shaped bend lead pins utilizing containers (1) for transport, in which the IC packages (3) are mounted upside down such that the lead pins cannot be moved to collide against anything within the container during transport. The method thus ensures that the leads of the IC packages are not deformed and loss of the flatness of the leads can be prevented during transport.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a container structure for IC (integrated circuit) packages and a method of transporting IC packages having J-shaped bend lead pins, and particularly a method of transporting so called &#34;PLCC&#34; IC packages having lead pins on four sides thereof in such a manner that the lead pins of the packages can be protected from damage due to shocks during transport. 
     2. Prior Art 
     Hitherto, tube-shaped containers such as the container 6 shown in FIG. 5 have been used to transport PLCC IC packages. Tube-shaped container 6 has an opening 201 and is provided with a chamfered surface 202 provided for indicating the position or direction of the PLCCs stored in the container. FIG. 6 is a sectional view of such a container in which a PLCC 3 has been inserted. PLCCs 3 are inserted into the container 6 via the opening 201, with the lead pins directed downward. 
     One problem presented by this known container is that the lead pins of the PLCCs can touch the container when the PLCCs are inserted into the container and further the lead pins of one PLCC can touch the lead pins of adjacent PLCCs after they have been stored in the container. Thus, shocks to the container may cause the lead pins of the IC packages to collide against the container walls or against the lead pins of the neighboring IC packages during transport, resulting in deformation of the lead pins and therefore in loss of flatness thereof. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a container for PLCCs and a method of transporting PLCCs without deforming the lead pins thereof. 
     A container for IC packages according to the present invention is characterized by that IC packages are stored upside down therein in such a manner that the leads of a stored IC package can never be substantially contacted by the container itself or by an IC package stored adjacent thereto. 
     Further, the present invention provides a method of transporting PLCCs, characterized in that the IC packages are stored upside down in the container and that the IC packages are transported so that the leads thereof can never be substantially contacted by the container itself and by an IC package stored adjacent thereto. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described, by way of example, with reference to the accompanying drawings, in which: 
     FIGS. 1(a), 1(b) and 1(c) are perspective views showing an embodiment of the present invention; 
     FIG. 2 is a sectional view showing a principal part of a container according to the invention; 
     FIG. 3 is a sectional view showing the coupled lid and body of the container of FIG. 2; 
     FIG. 4 is a sectional view showing a principal part of another embodiment of a container according to the invention; 
     FIG. 5 is a perspective view of a container in accordance with the prior art; 
     FIG. 6 is a sectional view of the prior art container of FIG. 5; 
     FIGS. 7(a) and 7(b) are sectional views of a part of other embodiments according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1(a), 1(b) and 1(c) are perspective views showing an embodiment of the invention, composed of a container body 1 and a lid 4. Body 1 is provided with pockets 2 for storage of PLCCs 3. A band 5 is provided for fixing container body 1 and lid 4 together. Specifically, FIG. 1(a) shows the container body before it is closed by lid 4, and FIG. 1(b) shows them in a position in which they are to be transported. FIG. 1(c) shows the underside of the lid 4, 103 being projections for preventing the lead pins of a PLCC 3 from touching lid 4. 
     FIG. 2 is a sectional view showing a principal part of the container of FIG. 1, in which 101 designates an oblique surface for positioning a PLCC 3 in a storage pocket 2, and 102 designates another oblique surface for protection of the lead pins 7 of PLCC 3. Surfaces 101 and 102 are provided on projections which extend upwardly to the underside of lid 4 and which extend between opposed sides of a body 1 to define the individual pockets. 
     The vertical height H 1  of each oblique surface 101 is smaller than the vertical distance Q 1  from the package&#39;s (inverted) top face to the top edge of lead pins 7 projecting from package 3 (H 1  &lt;Q 1 ) Further, the oblique surface 102 is in a position recessed from the associated oblique surface 101 so that lead pins 7 of PLCC 3 will not be brought into contact with any surface within the container and will thus be protected even if PLCC 3 should shift horizontally within storage pocket 2. 
     On the other hand, the depth H 2  of the storage pocket 2 is greater than the overall package height Q 2  (H 2  &gt;Q 2 ). Each projection 103 has a height H 3  which is sufficiently large to ensure that the free ends of lead pins 7 will not touch lid 4 even if the PLCC 3 is moved vertically, i.e., if the container is turned upside down. 
     To completely protect lead pins 7, the difference between H 1  and Q 1  should be equal to or greater than 0.5 mm, and the difference between H 2  and Q 2  should be equal to or greater than 1 mm. The dimensions of the pocket 2 and H 3  should be determined such that PLCC 3 can move within storage pocket 2 to an extent of about 0.5 mm horizontally and to an extent of about 0.2 mm vertically. Further, there should be provided a horizontal spacing of greater than 2 mm between the edges of projection 103 and lead pins 7. 
     FIG. 3 shows a principal part of the container 1 and lid 4 coupled together. The gap G 1  existing when the container 1 and the lid 4 are coupled together, should be within a range of 0.5 mm or less in order to ensure that horizontal movement of the lid 4 cannot cause a projection 103 to touch the lead pins 7. 
     The materials of the container 1 and lid 4, including projections 103, must be selected so that a dimensional precision of at least ±0.3 mm can be ensured, in order that the above-mentioned various dimensional requirements can be met. Further, in view of weight requirements, costs, and electrostatic breakdown of the IC packages to be stored in the container, the container materials should be industrial plastics treated against electrostatic breakdown. Container 1 and lid 4, including projections 103, may all be made of the same material. 
     FIG. 4 is a cross section of a principal part of another embodiment of the present invention, which comprises a container 1 whose bottom can serve as a lid for an underlying container. No separate lid is therefore needed. Stacking of such containers will automatically close each container and the topmost container of a stack will not contain PLCCs and will simply serve as a lid. Many PLCCs can be transported simultaneously by the use of such containers stacked up on one another. 
     FIGS. 7(a) and 7(b) are sectional views of the part of other forms for the off projections provided in container body 1. FIG. 7(a) shows a structure in which surfaces 101 are on projection parts separated from that providing surfaces 102. FIG. 7(b) shows a structure in which there is no surface 102. 
     The transport method according to the invention, which utilizes a container in which PLCCs are stored upside down and which thus enable easy protection of the lead pins of the PLCCs, has significant advantages in that the lead pins of the PLCCs stored in the containers can be protected from being deformed by shocks during transport, whereby deformation of the lead pins cannot occur. 
     While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention. 
     The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.