Surface mount semiconductor package, die-leadframe combination and leadframe therefor and method of mounting leadframes to surfaces of semiconductor die

• US 6,307,755 B1
• Filed: 05/27/1999
• Issued: 10/23/2001
• 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, Alexander K., Williams, Richard K., Lam, Allen K.
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): FOSTER, DAVID A
• Application Number:
  US09/322,127
• Time in Patent Office: 880 Days
• Field of Search: 361/813, 361/820, 361/760, 361/764, 361/767, 257/666, 257/668, 257/669, 257/670, 257/672, 257/673, 257/676, 174/52.1, 174/52.4, 174/260, 174/261
• US Class Current: 361/813
• CPC Class Codes: H01L 2224/02166 Collar structures
• CPC Class Codes: H01L 2224/023 Redistribution layers [RDL] for bonding areas
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/04042 Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
• CPC Class Codes: H01L 2224/05552 in top view
• CPC Class Codes: H01L 2224/05556 in side view
• CPC Class Codes: H01L 2224/05558 conformal layer on a patterned surface
• CPC Class Codes: H01L 2224/05624 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• CPC Class Codes: H01L 2224/13144 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/16245 the item being metallic
• 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 2224/2919 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/32057 in side view
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/37147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/40245 the item being metallic
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45124 : Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 : Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/4554 : Coating
• CPC Class Codes: H01L 2224/48091 : Arched
• CPC Class Codes: H01L 2224/48227 : connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48247 : connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48453 : of the interface with the bonding area
• 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 2224/4847 : the connecting portion on the bonding area of the semiconductor or solid-state body being a wedge bond
• CPC Class Codes: H01L 2224/4848 : outside the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/48624 : Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/48724 : Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/49111 : the connectors connecting two common bonding areas, e.g. Litz or braid wires
• CPC Class Codes: H01L 2224/49171 : Fan-out arrangements
• CPC Class Codes: H01L 2224/73221 : Strap and wire connectors
• CPC Class Codes: H01L 2224/73253 : Bump and layer connectors
• CPC Class Codes: H01L 2224/73265 : Layer and wire connectors
• CPC Class Codes: H01L 2224/81205 : Ultrasonic bonding
• CPC Class Codes: H01L 2224/83051 : Forming additional members, e.g. dam structures
• CPC Class Codes: H01L 2224/8314 : Guiding structures outside the body
• CPC Class Codes: H01L 2224/83192 : wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• 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 2224/83855 : Hardening the adhesive by curing, i.e. thermosetting
• 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 2224/85 : using a wire connector
• 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 2224/92 : 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 23/49562 : for devices being provided for in H01L29/00
• CPC Class Codes: H01L 24/03 : Manufacturing methods
• CPC Class Codes: H01L 24/05 : of an individual bonding area
• CPC Class Codes: H01L 24/33 : of a plurality of layer connectors
• 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 24/49 : of a plurality of wire connectors
• CPC Class Codes: H01L 24/83 : using a layer connector
• 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 2924/0001 : Technical content checked by a classifier
• 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 2924/01005 : Boron [B]
• 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 2924/01021 : Scandium [Sc]
• CPC Class Codes: H01L 2924/01022 : Titanium [Ti]
• CPC Class Codes: H01L 2924/01027 : Cobalt [Co]
• CPC Class Codes: H01L 2924/01028 : Nickel [Ni]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01039 : Yttrium [Y]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01051 : Antimony [Sb]
• CPC Class Codes: H01L 2924/01056 : Barium [Ba]
• CPC Class Codes: H01L 2924/01057 : Lanthanum [La]
• CPC Class Codes: H01L 2924/01058 : Cerium [Ce]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/05042 : Si3N4
• CPC Class Codes: H01L 2924/0665 : Epoxy resin
• CPC Class Codes: H01L 2924/07802 : not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• 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 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/19043 : being a resistor
• CPC Class Codes: H01L 2924/20755 : larger or equal to 50 microns less than 60 microns
• CPC Class Codes: H01L 2924/20757 : larger or equal to 70 microns less than 80 microns
• CPC Class Codes: H01L 2924/2076 : equal to or larger than 100 microns
• CPC Class Codes: H01L 2924/3512 : Cracking

Abstract

A leadframe for making an electric connection to a semiconductor die contains a plurality of notches which correspond to the edges of the die. Shorts are thereby prevented between the leadframe and electrical elements near the edge of the die, even when the leadframe is bent in the direction of the die to make a surface mount package. Alternatively or additionally, the leads in the leadframe may contain moats which prevent the epoxy or solder used to attach the leadframe to a die from spreading outward and thereby creating electrical shorts with other leads.

Claims

1. A die-leadframe combination comprising:

a die having first and second principal surfaces;

a first leadframe having a first tie bar connected to a portion of said first leadframe that exerts a pressure in a first direction against the first principal surface of the die;

a second leadframe having a second tie bar connected to a portion of said second leadframe that exerts a pressure in a second direction opposite to the first direction against the second principal surface of the die;

wherein the first and second tie bars are offset with respect to each other such that the pressure of the first and second leadframes against the die in the first and second directions, respectively, creates a torque on the die.

2. A method of mounting first and second leadframes to first and second surfaces of a semiconductor die such that substantially no torque is applied to the die during the mounting.

3. The method of claim 2 wherein the first leadframe comprises a first outer tie bar and a first center tie bar and the second leadframe comprises a second outer tie bar and a second center tie bar and wherein the first center tie bar is positioned laterally between the second center tie bar and the second outer tie bar during the mounting.

4. The method of claim 3 wherein the second center tie bar is positioned laterally between the first center tie bar and the first outer tie bar.

5. The method of claim 4 comprising applying a conductive epoxy to the first and second surfaces of the die and allowing the epoxy to cure.

6. The method of claim 5 wherein the die is subjected to substantially no torque while the epoxy is curing.

7. The method of claim 6 comprising trimming the leadframes so as to separate the outer tie bars from leads, wherein the die is subjected to substantially no torque during the trimming.

8. The method of claim 7 comprising bending one or more of the leads wherein the die is subjected to substantially no torque during the bending.

9. A semiconductor die package comprising a semiconductor die and a leadframe attached to a surface of the die, a plurality of leads extending from the surface beyond an edge of the die, a notch being formed in at least one lead at a location where the at least one lead passes over the edge of the die, the notch being formed on a side of the at least one lead facing the die.

10. The semiconductor package of claim 9 comprising a second leadframe attached to a second surface of the die, a second plurality of leads extending from the second surface beyond a second edge of the die, a second notch being formed in a second lead of the second leadframe at a location where the second lead passes over the second edge of the die, the second notch being formed on a side of the second lead facing the die.

11. The semiconductor package of claim 10 comprising a plastic capsule enclosing the die, the first and second pluralities of leads extending from the capsule at the same level.

12. The semiconductor package of claim 11 wherein the first plurality of leads are bent at a location within the capsule.

13. A leadframe for use in forming an electrical connection with a semiconductor die in a package, the leadframe comprising a lead, the lead having a plurality of notches such that the leadframe is capable of being used with dice of more than one size, one of the notches being positioned over an edge of each of the dice.