National Semiconductor Corporation

Chan Peng Yeen

Jaime A Bayan

Santhiran Nadarajah

Sharon Ko Mei Wan

Peter Howard Spalding

Harry Kam Cheng Hong

Hu Ah Lek

Ashok S Prabhu

Nghia Thuc Tu

Santhiran S/o Nadarajah

Lim Fong

Hasfiza Ramley

Lim Peng Soon

Chan Chee Ling

Jamie A Bayan

In one aspect of the invention, a method of attaching a semiconductor die to a microarray leadframe is described. The method comprises stamping an adhesive onto discrete areas of the microarray leadframe using a multi-pronged stamp tool. The adhesive is applied to the leadframe as a series of dots, each dot corresponding to an associated prong of the stamping tool. In some embodiments the adhesive used to attach the semiconductor die to a leadframe is a black epoxy based adhesive material. In an apparatus aspect of the invention, lead traces in a microarray leadframe are arranged to have tails that extend beyond their associated contact posts on the side of the contact post that is opposite a wire bonding region such that such lead traces extends on two opposing sides of their associated contact posts. The tails do not attach to other structures within the lead frame (such as a die attach structure). The width of at least some of these tailed lead traces in a region that overlies their associated contact post is narrower than their associated contact post. Thus, these narrowed lead traces have extensions that extend beyond their associated contact posts. The extensions provide additional surface area that gives an adhesive applied to the narrowed lead trace (as for example by stamping) room to bleed (flow) along the top surface of the lead trace on both sides of the associated contact pad.

Die attach method and leadframe structure

Die attach method and microarray leadframe structure

Aspects of the invention recite wire bonding on thinned portions of a lead-frame that is configured for use in an IC package. A harder lead-frame material, improved adhesive tape, and various structural features of the lead-frame itself, in various combinations or subcombinations, facilitate the attachment of wire bonds to thinned areas of the lead-frame. This eliminates the need for supports placed directly under the bond sites, removing unwanted conductive areas on the outer surface of an IC package.

Wire bonding on thinned portions of a lead-frame configured for use in a micro-array integrated circuit package

A method of fabricating a micro-array IC package is recited. A wafer has a B-stageable adhesive applied, and the wafer is diced. The individual dice are applied to a lead-frame via their adhesive, and wirebonded to associated leads. The lead-frame is then encapsulated, and solder connectors are applied. The lead-frame is then singulated to produce a plurality of lead-frame based micro-array packages. The process thus allows lead-frame based manufacturing methods to be employed in the production of BGA-type packages, allowing such packages to be produced faster and more efficiently.

Method of fabricating a micro-array integrated circuit package

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 wire bonding technique for manufacturing semiconductor devices that results in a bonded wire having a small loop height. The wire bonding technique involves a capillary tool that ball bonds a wire to a first contact point, then moves upwards, and then towards a second contact point to which the wire will be attached. The capillary tool only moves towards the second contact point in the lateral direction. The height of the wire loop of the bonded wires can be controlled to have desired wire loop heights. The bonding technique can be used in semiconductor devices with stacked dice and in devices where a die and a contact lead are approximately at the same height.

Ultra-low loop wire bonding

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.

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

Chan Peng Yeen