Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
  • H10D84/00—Integrated devices formed in or on semiconductor substrates that comprise only semiconducting layers, e.g. on Si wafers or on GaAs-on-Si wafers
  • H10D84/01—Manufacture or treatment
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W70/00—Package substrates; Interposers; Redistribution layers [RDL]
  • H10W70/40—Leadframes
  • H10W70/421—Shapes or dispositions
  • H10W70/424—Cross-sectional shapes
  • H10W70/427—Bent parts
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W70/00—Package substrates; Interposers; Redistribution layers [RDL]
  • H10W70/40—Leadframes
  • H10W70/421—Shapes or dispositions
  • H10W70/442—Shapes or dispositions of multiple leadframes in a single chip
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W74/00—Encapsulations, e.g. protective coatings
  • H10W74/01—Manufacture or treatment
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W74/00—Encapsulations, e.g. protective coatings
  • H10W74/01—Manufacture or treatment
  • H10W74/016—Manufacture or treatment using moulds
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W90/00—Package configurations
  • H10W90/811—Multiple chips on leadframes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/01—Manufacture or treatment
  • H10W72/0198—Manufacture or treatment batch processes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/071—Connecting or disconnecting
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/071—Connecting or disconnecting
  • H10W72/072—Connecting or disconnecting of bump connectors
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/071—Connecting or disconnecting
  • H10W72/072—Connecting or disconnecting of bump connectors
  • H10W72/07231—Techniques
  • H10W72/07234—Using a reflow oven
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/071—Connecting or disconnecting
  • H10W72/072—Connecting or disconnecting of bump connectors
  • H10W72/07231—Techniques
  • H10W72/07236—Soldering or alloying
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/20—Bump connectors, e.g. solder bumps or copper pillars; Dummy bumps; Thermal bumps
  • H10W72/251—Materials
  • H10W72/252—Materials comprising solid metals or solid metalloids, e.g. PbSn, Ag or Cu
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/20—Bump connectors, e.g. solder bumps or copper pillars; Dummy bumps; Thermal bumps
  • H10W72/29—Bond pads specially adapted therefor
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/851—Dispositions of multiple connectors or interconnections
  • H10W72/874—On different surfaces
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W74/00—Encapsulations, e.g. protective coatings
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W74/00—Encapsulations, e.g. protective coatings
  • H10W74/10—Encapsulations, e.g. protective coatings characterised by their shape or disposition
  • H10W74/111—Encapsulations, e.g. protective coatings characterised by their shape or disposition the semiconductor body being completely enclosed
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W90/00—Package configurations
  • H10W90/701—Package configurations characterised by the relative positions of pads or connectors relative to package parts
  • H10W90/721—Package configurations characterised by the relative positions of pads or connectors relative to package parts of bump connectors
  • H10W90/726—Package configurations characterised by the relative positions of pads or connectors relative to package parts of bump connectors between a chip and a stacked lead frame, conducting package substrate or heat sink
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W90/00—Package configurations
  • H10W90/701—Package configurations characterised by the relative positions of pads or connectors relative to package parts
  • H10W90/791—Package configurations characterised by the relative positions of pads or connectors relative to package parts of direct-bonded pads
  • H10W90/796—Package configurations characterised by the relative positions of pads or connectors relative to package parts of direct-bonded pads between a chip and a stacked lead frame, conducting package substrate or heat sink

Definitions

• Integrated circuit (IC) packages typically include an IC die attached to a lead frame that enables contacts on the die to be attached to exterior circuits.
• the die and portions of the leadframe are often encapsulated in a covering of epoxy or other material that protects the die and leadframe.
• IC dies have become smaller over time the number and density of contacts on the dies have increased.
• signal routing within the IC packages and heat dissipation from IC packages has become challenging.
• One recent development is the dual leadframe IC package in which more than one leadframe is provided in a single package to increase signal routing options.
• dual leadframe packages often pose added challenges of their own, such as a tendency of the two leadframes to make undesired electrical contact with each other. Such contact may result in a short circuit and package failure.
• Fig. 1 is a bottom perspective view of a top lead frame strip and flipchip dies.
• Fig. 2 is a bottom perspective view of the lead frame strip of Fig. 1 with flipchips mounted on each lead frame.
• FIG. 3 is a top perspective view of a top lead frame strip and bottom lead frame strip prior to attachment.
• Fig. 4 is a top perspective view of attached top and bottom lead frame strips and flipchip dies attached therebetween and further showing the mounting of discrete circuit components on one top lead frame.
• Fig. 5 is a top perspective view of attached top and bottom lead frame strips of Fig. 4 with discrete circuit components mounted on each top lead frame thereof.
• Fig. 6 is a top perspective view of three encapsulated dual lead frame assemblies such as shown in Fig. 5.
• Fig. 7 is a cross-sectional side elevation view of an integrated circuit package singulated from a molded dual lead frame assembly such as shown in Fig. 6.
• Fig. 8 is a bottom perspective view of the integrated circuit package shown in Fig. 7.
• Fig. 9 is a top perspective view of the integrated circuit package shown in Figs. 7 and 8.
• FIG. 10 is a flow chart of one embodiment of a method of making integrated circuit modules.
• Fig. 1 illustrates a top lead frame strip 10 having integrally connected top lead frames 12, 14, 16, 18.
• the top lead frame strip 10 has a bottom surface 22 and a top surface 24, Fig. 3.
• Each top lead frame 12, 14, etc. has a plurality of generally coplanar contact pad portions 30 including individual contact pads 31 , 32, 33, 34, 36, 38, etc. Some of the contact pads, e.g., 31 , 33, etc., are mounted in a generally rectangular die mounting area 37 of each top lead frame, e.g., 12.
• Each lead frame also comprises a plurality of peripheral lead portions 50 which may comprise a plurality of relatively large lead portions 52, 54, 56, 58 and a plurality of relatively small lead portions 53, 55, 57, etc.
• One or more interior lead portions 59 may also be provided on each top leadframe 12, etc. Interior lead portion 59 may be attached to the die attachment pad (DAP) portion 130 of a bottom leadframe 1 10, described below.
• Each peripheral lead portion 50 has a proximal end 60 attached to at least one contact pad portion 30 and also comprises a downwardly and outwardly extending distal end 62.
• At least some of the peripheral lead portions 50 comprise connector extensions 64, 65, which may have a generally inverted U-shape or an inverted L-shape depending upon whether there is an adjacent connected leadframe.
• the connector extensions 64, 65 facilitate attachment of the top leadframe strips 10 to bottom leadframe strips 1 10, Fig. 3.
• the connector extensions 64, 65 may comprise other shapes adapted to facilitate connection between top and bottom leadframe strips 10, 1 10.
• a plurality of flipchips 72, 74, 76, 78 are mounted on the top lead frames 12, 14, 16, 18 respectively.
• Each flipchip has a first or active side 82 and a second or inactive side 84 as best seen in the cross-sectional view of Fig. 7.
• the active side 82 has a plurality of solder bumps 85, 87, 89, etc., formed thereon in a rectangular grid pattern.
• Each of the solder bumps is bonded to an associated contact pad portion, e.g., 31 , 33 in die mounting region 37 during reflow heating.
• the top lead frame strip 10 may be moved to a reflow oven (not shown) for soldering the flipchips 72, etc. to the top leadframes 12, etc., when in the configuration shown in Fig. 2, which is prior to attachment of the top lead frame strip 10 to a bottom lead frame strip.
• Fig. 3 illustrates a bottom lead frame strip 1 10 having interconnected bottom lead frames 1 12, 1 14, 1 16, 1 18.
• the bottom lead frame strip 1 10 has a top surface 122 and a bottom surface 124.
• a die attachment pad (DAP) portion 130 is connected to a peripheral frame portion 132 which may be formed by a plurality of elongate frame members 134, 136, 138, 142. Each DAP portion 130 is circumscribed by an associated peripheral frame portion 132.
• the DAP portion 130 is connected to the surrounding peripheral frame portion 132 by a plurality of tie bars 152, 154, 156, 158.
• Each bottom lead frame 1 12, 1 14, etc. comprises an elongate lead bar 160 which is positioned in a plane parallel to and above a plane in which the DAP portion 130, peripheral frame portion 132 and tie bar portions 152, etc. are positioned.
• a first lead bar lead portion 162 and a second lead bar lead portion 164 are attached to opposite ends of the lead bar 160.
• Lead bar lead portions 162, 164 are integrally formed with and attached at distal ends thereof to an elongate side member 134 of the associated peripheral frame portion132.
• the distal end 168 at each lead bar lead portion 162, 164 is positioned substantially in the same plane as the DAP portion 130 and peripheral frame portion132.
• the lead bar 160 is positioned substantially in the same plane as the top leadframe contact pad portions 30 and engages the bottom surface of at least one of the contact pad portions 30.
• the top lead frame strip 10 after attachment of the flipchips 72, 74, 76, 78 thereto is attached, bottom surface 22 down, to the bottom lead frame strip 1 10 to form a dual leadframe strip 170. This is done, in one embodiment, by placing solder paste on the peripheral frame portions 132 and the lead bars 160 of the bottom lead frame strip 1 10 and then positioning the connector extensions 64, 65 of the top leadframe peripheral lead portions 50 in contact with the associated peripheral frame portions 132 and the bottom leadframe lead bars 160 into contact with the top leadframe contact pad portions 130.
• the top lead frame strip 10 "nests" on the bottom lead frame strip 1 10 through a positive and locating engagement of the lead portion connector extensions 64, 65 with the peripheral frame portions 132.
• each of the top lead frame peripheral lead portions 50 and the lead bar lead portions 162, 164 act as vertical spacers in the dual lead frame strip assembly 170 shown in Fig. 4.
• the peripheral lead portions 50 of the top leadframes 10, 12, etc. also co-act with the peripheral frame portions 132 of the bottom leadframes 1 10, 1 12, etc. for proper lateral and angular positioning of the leadframes.
• the lead distal end portions 62 and the lead bar lead portions 162, 164 hold the top lead frame contact pad portions 30 at a predetermined height above the bottom lead frame DAP portions 130 and peripheral frame portions 132.
• the lead distal end portions 62 also hold the contact pad portions 30 in a generally laterally centered relationship with respect to the peripheral frame portions 132 of each bottom lead frame 1 12, 1 14, 1 16, 1 18.
• a plurality of discrete components which may be passive circuit components 182, 184, 186 may be mounted on the top surface of each top lead frame 12, 14, 16, 18. This may be accomplished by first applying solder paste to associated contact pad portions 30 of each top lead frame. The discrete circuit components 182, 184, 186 are then solder bonded to the associated top lead frames, e.g., 16, by placing the dual lead frame strip 170 in a reflow oven. In one method, the reflow heating of the solder paste beneath each discrete component 182, 184, 186 may take place at the same time as reflowing of the solder paste on the peripheral frame portions 132, etc.
• solder paste on the bottom lead frame is reflowed in a first operation before the discrete members 182, 184, 186 are placed on the associated top lead frames, e.g., 16.
• Fig. 5 illustrates the dual lead frame strip 170 after mounting of the discrete components 182, 184, 186 on each top lead frame 12, 14, 16,18.
• the dual lead frame assembly 170 of Fig. 5 is placed on a support frame 194, Fig. 6, and is moved to an encapsulation station such as a transfer mold station where mold compound is applied to the dual lead frame strip assembly 170 to provide an encapsulated dual lead frame strip 190.
• an encapsulation station such as a transfer mold station where mold compound is applied to the dual lead frame strip assembly 170 to provide an encapsulated dual lead frame strip 190.
• encapsulating material 200 such as conventional mold compound which cures to provide a hard protective covering.
• the encapsulated dual lead frame strip 190 thus formed may be of various sizes and lengths depending upon the size and length of the top and bottom lead frames 10, 1 10 that were initially attached together.
• the encapsulated dual lead frame strip 190 illustrated in Fig. 6 has three, 2x2 dual lead frame assemblies 170 covered with encapsulating material 200.
• the encapsulated dual lead frame strip 190 has a generally flat top surface 192 and flat bottom (not shown) and side surfaces 195.
• the dashed lines shown at 196 represent the boundaries of three 4X4 encapsulated dual lead frame strips 190.
• Each 4X4 encapsulated leadframe assembly 190 is then singulated along the saw streets 100, 101 , 102, 103 (Figs. 1 -5) around each individual attached top and bottom leadframe assembly, e.g., 12,1 12.
• the singulation of an encapsulated dual lead frame strip 190 provides a plurality of individual integrated circuit (IC) packages 210, each having a flat top face 212, a flat bottom face 214 and a plurality of flat side faces 216.
• a bottom surface 131 of a DAP portion 130 is exposed at the bottom face 214 of each IC package.
• bottom surface portions 66 and terminal end surface portions 68 of the top lead frame lead portions 50 including smaller lead portions 53, 55, etc. as well as larger lead portions 52, 54, etc.
• exposed are surface portions of bottom lead frame lead portions 162, 164.
• the exposed bottom surface 131 of the DAP portion 130 may be substantially flush with the bottom face 214 of the encapsulating layer 200.
• the exposed surfaces of the severed distal end portions 62 of the top leadframe peripheral leads 50 and of the severed distal end portion 168 of each lead bar lead portion 162, 164 may be substantially flush with the bottom face 214 and side faces 216 of the encapsulating layer 200.
• each top leadframe e.g., 12
• each bottom lead frame e.g., 1 12
• a significant gap 92 Fig. 7
• a common dual leadframe problem of top leadframes leads making undesired contact with and shorting out on the bottom lead frame is obviated.
• additional signal routing options are provided to the package designer. Although in the specifically described embodiments only one lead bar and two additional leads are provided it is to be understood that additional leads and thus additional signal routing options could be provided.
• Fig. 10 illustrates a method of making integrated circuit packages. As shown in Fig. 10, the method includes, as shown at block 231 , providing a top
• leadframe strip 10 comprising a plurality of integrally connected top leadframes 12, 14, etc.
• the method also includes, as shown at 232, mounting a plurality of flipchip dies 72, 74, etc., on the top leadframe strip 10 with solder bumps 85, 87, etc., of each flipchip die bonded to predetermined contact pad portions 30 on each of the top leadframes 12, 14, etc.
• the method further includes, as shown at 233, providing a bottom leadframe strip 1 10 comprising a plurality of integrally connected bottom leadframes 1 12, 1 14, etc., each having a central die attach pad (DAP) portion 130 and a peripheral frame portion 132.
• DAP central die attach pad
• the method also includes, as shown at block 234, attaching the top leadframe strip 10 to the bottom leadframe strip 1 10 with a back face 84 of each flipchip die 72, etc., contacting the DAP portion 130 of each bottom leadframe 1 12, 1 14, etc., and with peripheral lead portions 50 of each top leadframe 12, 14, etc., attached to the peripheral frame portion 132 of each bottom leadframe 1 12, 1 14, etc.

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• Lead Frames For Integrated Circuits (AREA)
• Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)

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• 2013
  • 2013-01-09 US US13/737,697 patent/US8884414B2/en active Active
• 2014
  • 2014-01-09 WO PCT/US2014/010860 patent/WO2014110247A1/en not_active Ceased
  • 2014-01-09 JP JP2015552768A patent/JP6261055B2/ja active Active
  • 2014-01-09 CN CN201480003922.6A patent/CN104956782B/zh active Active
  • 2014-05-01 US US14/267,565 patent/US9029194B2/en active Active

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