Patent Publication Number: US-2015083641-A1

Title: Selective heat seal wafer cover tape (has tape)

Description:
FIELD OF THE INVENTION 
     This invention relates to the field of integrated circuits. More particularly, this invention relates to reel and tape packaging of surface mount devices and the cover tape used to close the carrier tape after the integrated circuit has been inserted into the carrier tape 
     BACKGROUND OF THE INVENTION 
     Wafer level chip size packages, surface mount die and other integrated circuit products are typically shipped in carrier tape and reel wherein every package, surface mount die or product is placed into a separate pocket in the carrier tape. In this way, pick and place mounting equipment on the assembly line can pick the packages or surface mount die out of the pockets and place them directly onto a printed circuit board (PCB). 
     After the packages or surface mount die are inserted into the pockets on the tape, the tape is then covered with a cover tape, thus closing the pockets and securing the packages or surface mount die in the carrier tape. The carrier tape is then rolled onto a reel that is compatible with pick and place mounting equipment and shipped to the customer. 
     The customer inserts the reel into the mounting equipment, wherein the mounting equipment removes the cover tape so that the equipment can remove each package or surface mount die from the tape and place them on the PCB for mounting. 
     Typically the cover tape has adhesive on one side of the cover tape to adhere the cover tape to the carrier tape. The adhesive is continuous over the one entire surface of the tape. During shipment or during the mounting process, the package or surface mount die may adhere themselves to the exposed adhesive over the pocket in the tape. This can cause problems with the mounting equipment during the mounting processes. 
     In view of the foregoing, there is a need to provide a method of preventing the packages or surface mount die from sticking to the cover tape. 
     SUMMARY OF THE INVENTION 
     The following presents a simplified summary in order to provide a basic understanding of one or more aspects of the invention. This summary is not an extensive overview of the invention, and is neither intended to identify key or critical elements of the invention, nor to delineate the scope thereof. Rather, the primary purpose of the summary is to present some concepts of the invention in a simplified form as a prelude to a more detailed description that is presented later. 
     In In accordance with an embodiment of the present application, a tape and reel shipping container is provided. The tape and reel shipping container, comprises: a carrier tape covered by a cover tape; the carrier tape is constructed of antistatic material and has two parallel edges with pockets disposed there between; the pockets are separated from the parallel edges and each other, wherein the space between the pockets and the parallel edges is sufficient to provide a good sealing surface, wherein the pockets are configured to hold either packages or surface mount die; wherein, one of the spaces between the pockets and the parallel edges is extended to provide space for index holes; the index holes are configured to be connected to an indexing sprocket in either a packaging machine or a surface mount machine; and wherein the cover tape seals the packages or surface mount die into the pockets of the carrier tape, thereby protecting the packages or surface mount die during shipment, wherein the cover tape is attached to the carrier tape by adhesive strips on the outer edges of the cover tape. 
     In accordance with another embodiment of the present application, a tape and reel shipping container is provided. The tape and reel shipping container, comprises: a carrier tape covered by a cover tape; the carrier tape is constructed of antistatic material and has two parallel edges with pockets disposed there between; the pockets are separated from the parallel edges and each other, wherein the spaces between the pockets and the parallel edges and between adjacent pockets is sufficient to provide a good sealing surface, wherein the pockets are configured to hold either packages or surface mount die; wherein, one of the spaces is extended to provide space for index holes; the index holes are configured to be connected to a indexing sprocket in either a packaging machine or a surface mount machine; and wherein the cover tape seals the packages or surface mount die into the pockets of the carrier tape, thereby protecting the packages or surface mount die during shipment, wherein the cover tape is attached to the carrier tape by an adhesive pattern on the cover tape. 
    
    
     
       DESCRIPTION OF THE VIEWS OF THE DRAWING 
         FIG. 1  shows an isometric view of the carrier tape along with the cover tape. 
         FIG. 2  shows of a plan view of a carrier tape covered by a cover tape of an embodiment of the present invention. 
         FIG. 2A  shows a cross section of the plan view of  FIG. 2  at A:A′ 
         FIG. 3  shows of a plan view of a carrier tape covered by a cover tape of another embodiment of the present invention. 
         FIG. 3A  shows a cross section of the plan view of  FIG. 3  at A:A′ 
     
    
    
     In the drawings, like reference numerals are sometimes used to designate like structural elements. It should also be appreciated that the depictions in the figures are diagrammatic and not to scale. 
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     The present invention is described with reference to the attached figures. The figures are not drawn to scale and they are provided merely to illustrate the invention. Several aspects of the invention are described below with reference to example applications for illustration. It should be understood that numerous specific details, relationships, and methods are set forth to provide an understanding of the invention. One skilled in the relevant art, however, will readily recognize that the invention can be practiced without one or more of the specific details or with other methods. In other instances, well-known structures or operations are not shown in detail to avoid obscuring the invention. The present invention is not limited by the illustrated ordering of acts or events, as some acts may occur in different orders and/or concurrently with other acts or events. Furthermore, not all illustrated acts or events are required to implement a methodology in accordance with the present invention. 
     The solution to the problem of the packages or surface mount die sticking to the cover tape is a new type of tape based on heat activated adhesive (HAA) ‘dry’ adhesive, but manufactured with limited range of adhesive coverage leaving the die areas uncovered and clear of adhesive 
     A typical cover tape has adhesive over a 100% coverage of the side of the cover tape facing the carrier tape with adhesive thus causing the package or surface mount die to adhere themselves to the exposed adhesive. The purpose of this invention is to prevent the package or surface mount die from adhere themselves to the exposed adhesive over the pocket in the carrier tape. This can cause problems with the mounting equipment during the mounting processes. 
     The root cause of packages or surface mount die sticking to the cover tape is 100% coverage of the side of the cover tape facing the carrier tape with adhesive.  FIG. 1  shows an isometric view of one embodiment to solve the problem. The cover tape has two stripes of adhesive on either edge of the tape, wherein no adhesive covers the pocket on the carrier tape. 
     A first embodiment of the invention is shown in  FIG. 2 .  FIG. 2  shows of a plan view of a carrier tape  208  covered by a cover tape of an embodiment of the present invention. The carrier tape  208  is constructed of antistatic material. The tape has two parallel edges  201  with pockets  202  disposed there between for shipping, packages  203  or surface mount die  203 . The pockets are separated from the parallel edges and each other, wherein the space  204  between the pockets and the parallel edges is sufficient to provide a good sealing surface. In addition, one or both of the spaces  204  is extended to provide space for index holes  205 . In this example, the space  204  is only expanded on one side. The index holes  205  supply connection to a indexing sprocket (not shown) in either the packaging machine or the surface mount machine. 
     A cover tape  207  is provided to seal the packages  203  or surface mount die  203 , into the pockets  202  of the carrier tape  208 , thereby protecting the packages  203  or surface mount die  203  during shipment. The cover tape  207  is attached to the carrier tape  208  by adhesive strips  206  What is the composition of the adhesive strips? on the outer edges of the cover tape  207 . The cover tape can be composed of an anti-static material or coated with an anti-static compound. The adhesive can be a heat activated adhesive (HAA) ‘dry’ adhesive. 
       FIG. 2A  shows a cross section of  FIG. 2  at A:A′. It is readily apparent that no adhesive  206  is located over packages  203  or surface mount die  203 , thus solving the problem of the packages or surface mount die from sticking to the cover tape. The adhesive strips can be applied with a coating process used for adhesive tapes. 
     A second embodiment of the invention is shown in  FIG. 3 .  FIG. 3  shows of a plan view of a carrier tape  208  covered by a cover tape of an embodiment of the present invention. The carrier tape  208  is constructed of antistatic material. The tape has two parallel edges  201  with pockets  202  disposed there between for shipping, packages  203  or surface mount die  203 . The pockets are separated from the parallel edges and each other, wherein the spaces  204  between the pockets and the parallel edges and between adjacent pockets is sufficient to provide a good sealing surface. In addition, one or both of the spaces  204  is extended to provide space for index holes  205 . In this example, the space  204  is only expanded on one side. The index holes  205  supply connection to a indexing sprocket (not shown) in either the packaging machine or the surface mount machine. 
     A cover tape  207  is provided to seal the packages  203  or surface mount die  203 , into the pockets  202  of the carrier tape  208 , thereby protecting the packages  203  or surface mount die  203  during shipment. The cover tape  207  is attached to the carrier tape  208  by an adhesive pattern  206  on the cover tape  207 . The cover tape can be composed of an anti-static material or coated with an anti-static compound. The adhesive can be a heat activated adhesive (HAA) ‘dry’ adhesive. The adhesive pattern  206  can be applied to the cover tape by either printing, screening or stenciling. 
       FIG. 3A  shows a cross section of  FIG. 3  at A:A′. It is readily apparent that no adhesive  206  is located over packages  203  or surface mount die  203 , thus solving the problem of the packages or surface mount die from sticking to the cover tape. 
     While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only and not limitation. Numerous changes to the disclosed embodiments can be made in accordance with the disclosure herein without departing from the spirit or scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above described embodiments. Rather, the scope of the invention should be defined in accordance with the following claims and their equivalents.