Package for semiconductor die containing symmetrical lead and heat sink

• US 6,800,932 B2
• Filed: 01/30/2002
• Issued: 10/05/2004
• Est. Priority Date: 05/27/1999
• Status: Expired due to Term

• Current Assignee: Advanced Analogic Technologies Incorporated (Skyworks Solutions Incorporated)
• Original Assignee: Advanced Analogic Technologies Incorporated (Skyworks Solutions Incorporated)
• Inventors: Choi, Alex K., Williams, Richard K., Lam, Allen K.
• Primary Examiner(s): WILLIAMS, ALEXANDER O
• Application Number:
  US10/066,023
• Publication Number:
  US 20020071253A1
• Time in Patent Office: 979 Days
• Field of Search: 257/706, 257/707, 257/669, 257/694, 257/666, 257/712, 257/713, 257/675, 257/674, 257/668, 257/696, 257/698, 257/717, 257/720, 257/796, 257/684, 257/690, 257/692, 257/86, 257/679, 257/678, 257/695, 257/776, 257/77, 361/704, 361/773, 361/813, 361/760, 361/764, 361/673, 361/820, 361/714, 174/52.1, 174/260, 174/261, 174/52.4
• US Class Current: 257/706
• CPC Class Codes: H01L 2224/05554 being square
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/26175 Flow barriers
• CPC Class Codes: H01L 2224/27013 for holding or confining the layer connector, e.g. solder flow barrier
• CPC Class Codes: H01L 2224/291 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/32057 in side view
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/37011 comprising apertures or cavities
• CPC Class Codes: H01L 2224/37147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/40095 Kinked
• CPC Class Codes: H01L 2224/40245 the item being metallic
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48464 the other connecting portion not on the bonding area also being a ball bond, i.e. ball-to-ball
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/4848 outside the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/48599 Principal constituent of the connecting portion of the wire connector being Gold (Au)
• CPC Class Codes: H01L 2224/73221 Strap and wire connectors
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83051 Forming additional members, e.g. dam structures
• CPC Class Codes: H01L 2224/83385 : Shape, e.g. interlocking features
• CPC Class Codes: H01L 2224/83801 : Soldering or alloying
• CPC Class Codes: H01L 2224/8385 : using a polymer adhesive, e.g. an adhesive based on silicone, epoxy, polyimide, polyester
• CPC Class Codes: H01L 2224/84801 : Soldering or alloying
• CPC Class Codes: H01L 2224/8485 : using a polymer adhesive, e.g. an adhesive based on silicone, epoxy, polyimide, polyester
• CPC Class Codes: H01L 2224/85051 : Forming additional members, e.g. for "wedge-on-ball", "ball-on-wedge", "ball-on-ball" connections
• CPC Class Codes: H01L 2224/85399 : Material
• CPC Class Codes: H01L 2224/92 : Specific sequence of method steps
• CPC Class Codes: H01L 2224/92247 : the second connecting process involving a wire connector
• CPC Class Codes: H01L 2224/97 : the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 23/4334 : Auxiliary members in encapsulations H01L23/49568 takes precedence
• CPC Class Codes: H01L 23/49524 : the additional leads being a tape carrier or flat leads
• CPC Class Codes: H01L 23/49562 : for devices being provided for in H01L29/00
• CPC Class Codes: H01L 23/49575 : Assemblies of semiconductor devices on lead frames
• CPC Class Codes: H01L 24/33 : of a plurality of layer connectors
• CPC Class Codes: H01L 24/35 : Manufacturing methods
• CPC Class Codes: H01L 24/37 : of an individual strap connector
• CPC Class Codes: H01L 24/40 : of an individual strap connector
• CPC Class Codes: H01L 24/45 : of an individual wire connector
• CPC Class Codes: H01L 24/48 : of an individual wire connector
• CPC Class Codes: H01L 24/73 : Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 24/84 : using a strap connector
• CPC Class Codes: H01L 24/97 : the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/00015 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed as prior art
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01015 : Phosphorus [P]
• CPC Class Codes: H01L 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/01027 : Cobalt [Co]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/1305 : Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/1306 : Field-effect transistor [FET]
• CPC Class Codes: H01L 2924/13062 : Junction field-effect transistor [JFET]
• CPC Class Codes: H01L 2924/13091 : Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15747 : Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/19043 : being a resistor
• CPC Class Codes: H01L 2924/3512 : Cracking

Abstract

A semiconductor package contains a plurality of sheet metal leads that are attached to one or more terminals on a top side of a semiconductor die. A heat sink is attached to a terminal on a bottom side of the die. Each of the leads extends across the die and beyond opposite edges of the die and is symmetrical about an axis of the die. At the locations where the leads pass over the edges of the die notches are formed on the sides of the leads which face the die, thereby assuring that there is no contact between the leads and the peripheral portion of the top surface of the die. Particularly in power MOSFETs the peripheral portion of the top surface normally contains an equipotential ring which is directly connected to the backside (drain) of the MOSFET, and hence a short between the leads on the top of the die and the equipotential ring would destroy the device. The result is a package that is extremely rugged and that is symmetrical about the axis of the die. To avoid shorting between adjacent leads, moats are formed in the leads where they face the die to prevent liquid epoxy or solder from spreading between the leads. Since no central tie bar is required, multiple dice can readily be packaged in a single plastic capsule.

Claims

1. A semiconductor package comprising:

a semiconductor die having upper and tower principal surfaces;

a metal heat sink in thermal contact with the lower principal surface of the die and in electrical contact with a first terminal on the lower principal surface of the die;

a first sheet metal lead spanning the upper principal surface of the die, said first sheet metal lead being in electrical contact with a second terminal on the upper principal surface of the die; and

a capsule encasing the die and at least a portion of the lead and the heat sink, opposite ends of the first sheet metal lead protruding from opposite sides of the capsule.

2. The semiconductor package of claim 1 further comprising a second sheet metal lead spanning the upper surface of the die, said second sheet metal lead being in electrical contact with a third terminal on the upper principal surface of the die.

3. The semiconductor package of claim 2 wherein said package is symmetrical about an axis, said axis being generally perpendicular to a longitudinal dimension of said sheet metal leads.

4. The semiconductor package of claim 2 wherein said die comprises a MOSFET, said first terminal comprises a drain terminal, said second terminal comprises a source terminal, and said third terminal comprises a gate terminal.

6. The semiconductor package of claim 1 wherein said metal heat sink includes a rim enclosed by said capsule.

7. The semiconductor package of claim 6 wherein said metal heat sink includes a notch located on an underside of said rim.

8. The semiconductor package of claim 1 wherein a plurality of holes are formed in a surface of said heat sink that is facing said lower principal surface of said die.

9. The semiconductor package of claim 8 wherein the plurality of holes are located in a portion of the surface of said heat sink that is not adjacent said lower principal surface of die.

10. The semiconductor package of claim 1 wherein a bottom of said heat sink protrudes from said capsule.

11. The semiconductor package of claim 1 wherein at least one lateral edge of said heat sink is exposed.

5. A semiconductor package comprising a sandwich, said sandwich comprising a heat sink, a semiconductor die, and a symmetrical sheet metal lead, said heat sink being bonded to said die and said die being bonded to said lead, said lead spanning a top surface of said die and having ends which protrude from opposite sides of said package, said sheet metal lead being symmetrical about an axis that is equidistant between the ends of the lead.