National Semiconductor Corporation

Sharon Ko Mei Wan

Jaime A Bayan

Santhiran Nadarajah

Chan Peng Yeen

Peter Howard Spalding

Harry Kam Cheng Hong

Hu Ah Lek

Methods and apparatuses for providing leadless leadframes with dummy contact leads are disclosed. A leadframe is described that includes an enclosed frame having two lengthwise portions and two widthwise portions. The leadframe also includes a device area array with dummy contact leads formed on the peripheral edges of the device area array. Furthermore, dummy contact leads are positioned along a tie bar such that they are directly opposite corresponding contact leads. By cutting along the tie bar, dummy contact leads are separated from the device area array.

Leadless leadframe packaging panel featuring peripheral dummy leads

A panel assembly of packaged integrated circuit devices including a conductive substrate panel having an array of device areas and a plurality of locking passageways. The locking passageways are positioned about an inactive buffer area which surrounds the periphery of the array of device areas. The panel assembly also includes a molded cap that is molded over the topside of the panel to encapsulate the array of device areas and the inactive buffer area. The molded cap includes conforming locking stem portions that extend into each of the locking passageways in a manner locking the molded cap to the substrate panel such that during singulation of the device areas, the molded cap will not separate from the substrate panel at the inactive buffer area. In another aspect of the invention, a method for producing the panel assembly having the locking passageways is described.

Locking of mold compound to conductive substrate panels

A leadless leadframe semiconductor package having a plurality of contacts, which have contact surfaces on the bottom surface of the package. At least some of the contacts have integrally formed stems that extend outward to the peripheral surface of the package. These stems have heights and widths less than the heights and widths of their corresponding contacts. A molded cap encapsulates at least a portion of the die, the stems and the contacts. Another aspect of the invention pertains to a leadless leadframe panel assembly having a conductive substrate panel that has at least one array of device areas, each array of device areas having a plurality of tie bars and a plurality of contacts. The contacts also have integrally formed stems that extend towards and connect to one of the tie bars. The stems have widths and heights that are less than the widths and heights of their corresponding contacts.

Leadless leadframe package design that provides a greater structural integrity

A leadless leadframe semiconductor package includes a plurality of contacts, at least some of which have integrally formed stems that extend to the peripheral surface of the package. These stems have heights and widths less than the heights and widths of their corresponding contacts. A molded cap encapsulates the stems and the contacts to leave contact surfaces of the contacts exposed on the bottom surface of the package. Another aspect of the invention pertains to a leadless leadframe panel assembly having a conductive substrate panel that has at least one array of device areas, which has a plurality of tie bars and a plurality of contacts. The contacts have integrally formed stems that extend towards and connect to one of the tie bars. The stems have widths and heights that are less than the widths and heights of their corresponding contacts.

A panel assembly of packaged integrated circuit devices comprising a conductive substrate panel having an array of device areas and a plurality of locking passageways. The locking passageways are positioned about an inactive buffer area which surrounds the periphery of the array of device areas. The locking passageways extend from a topside of the panel toward a bottom side of the panel. The panel assembly also includes a molded cap that is molded over the topside of the panel to encapsulate the array of device areas and the inactive buffer area. The molded cap includes conforming locking stem portions that extend into each of the locking passageways in a manner locking the molded cap to the substrate panel such that during singulation of the device areas, the molded cap will not separate from the substrate panel at the inactive buffer area. In another aspect of the invention, a method for producing the panel assembly having the locking passageways is described. The method involves providing a conductive substrate panel having the locking passageways and applying molding material to the topside of the substrate panel such that the solidified molding material forms stems that conform to the passageways.

Embodiments of the invention include an integrated circuit package and methods for its construction. An integrated circuit package of the invention includes a die attach pad and a plurality of lead pads. An integrated circuit die is mounted with the front side of the die attach pad and electrically connected to the plurality of lead pads. Additionally, the backside of the die attach pad includes a pattern of mesas formed thereon. Each of the mesas is configured such that they have a top surface area that is substantially the same size as the surface area of the lead pads. A contact layer of reflowable material is formed on the top surface of the mesas and the lead pads, forming an integrated circuit package with an improved contact layer.

Method and structure for applying thick solder layer onto die attach pad

A leadless leadframe semiconductor package comprising a plurality of contacts, which have contact surfaces on the bottom surface of the package. At least some of the contacts have integrally formed stems that extend outward to the peripheral surface of the package. These stems have heights and widths less than the heights and widths of their corresponding contacts. A molded cap encapsulates at least a portion of the die, the stems and the contacts. The molded cap leaves the contact surfaces of the contacts exposed on the bottom surface of the package, leaves a peripheral surface of the stems exposed on the peripheral surface of the package, and covers a bottom surface of each of the stems. Another aspect of the invention pertains to a leadless leadframe panel assembly having a conductive substrate panel that has at least one array of device areas, each array of device areas having a plurality of tie bars and a plurality of contacts. The contacts have contact surfaces on the bottom surface of the leadless leadframe panel assembly. The contacts also have integrally formed stems that extend towards and connect to one of the tie bars. The stems have widths and heights that are less than the widths and heights of their corresponding contacts. A molded cap encapsulates at least a portion of each die, the tie bars, the stems and the contacts while leaving the contact surfaces of the contacts exposed and covering a bottom surface of each of the stems.

A panel assembly of packaged integrated circuit devices including conductive substrate panel having an array of device areas and a plurality of locking passageways. The locking passageways are positioned about an inactive buffer area which surrounds the periphery of the array of device areas. The locking passageways extend from a topside of the panel toward a bottom side of the panel. The panel assembly also includes a molded cap that is molded over the topside of the panel to encapsulate the array of device areas and the inactive buffer area. The molded cap includes conforming locking stem portions that extend into each of the locking passageways in a manner locking the molded cap to the substrate panel such that during singulation of the device areas, the molded cap will not separate from the substrate panel at the inactive buffer area. In another aspect of the invention, a method for producing the panel assembly having the locking passageways is described. The method involves providing a conductive substrate panel having the locking passageways and applying molding material to the topside of the substrate panel such that the solidified molding material forms stems that conform to the passageways.

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Melaka, Malaysia

Sharon Ko Mei Wan