Method for fabricating stack die package

• US 9,589,929 B2
• Filed: 03/14/2013
• Issued: 03/07/2017
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: Vishay Siliconix
• Original Assignee: Vishay Siliconix
• Inventors: Terrill, Kyle, Kuo, Frank, Mao, Sen
• Primary Examiner(s): Feeney, Brett
• Assistant Examiner(s): NGUYEN, SOPHIA T
• Application Number:
  US13/830,041
• Publication Number:
  US 20140273344A1
• Time in Patent Office: 1,454 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 21/4853 Connection or disconnection of other leads to or from a metallisation, e.g. pins, wires, bumps
• CPC Class Codes: H01L 21/565 Moulds
• CPC Class Codes: H01L 21/566 Release layers for moulds, e.g. release layers, layers against residue during moulding
• CPC Class Codes: H01L 2223/54486 Located on package parts, e.g. encapsulation, leads, package substrate
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• CPC Class Codes: H01L 2224/06181 On opposite sides of the body
• CPC Class Codes: H01L 2224/27318 by dispensing droplets
• CPC Class Codes: H01L 2224/2732 Screen printing, i.e. using a stencil
• 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 2224/2929 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/29294 with a principal constituent of the material being a liquid not provided for in groups H01L2224/292 - H01L2224/29291
• CPC Class Codes: H01L 2224/293 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 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/33181 On opposite sides of the body
• 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 2224/40499 Material of the auxiliary connecting means
• CPC Class Codes: H01L 2224/4103 Connectors having different sizes
• CPC Class Codes: H01L 2224/41051 : Connectors having different shapes
• CPC Class Codes: H01L 2224/41052 : Different loop heights
• CPC Class Codes: H01L 2224/411 : Disposition
• CPC Class Codes: H01L 2224/41105 : Connecting at different heights
• CPC Class Codes: H01L 2224/4118 : being disposed on at least two different sides of the body, e.g. dual array
• CPC Class Codes: H01L 2224/45099 : Material
• CPC Class Codes: H01L 2224/48 : of an individual wire connector
• CPC Class Codes: H01L 2224/48091 : Arched
• CPC Class Codes: H01L 2224/48105 : Connecting bonding areas at different heights
• CPC Class Codes: H01L 2224/48245 : the item being metallic
• CPC Class Codes: H01L 2224/48247 : connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49052 : Different loop heights
• CPC Class Codes: H01L 2224/49105 : Connecting at different heights
• CPC Class Codes: H01L 2224/73221 : Strap and wire connectors
• CPC Class Codes: H01L 2224/73263 : Layer and strap connectors
• CPC Class Codes: H01L 2224/73265 : Layer and wire connectors
• CPC Class Codes: H01L 2224/73271 : Strap and wire connectors
• CPC Class Codes: H01L 2224/83191 : wherein the layer connectors are disposed only on the semiconductor or solid-state 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 2224/83801 : Soldering or alloying
• CPC Class Codes: H01L 2224/83815 : Reflow soldering
• CPC Class Codes: H01L 2224/8385 : using a polymer adhesive, e.g. an adhesive based on silicone, epoxy, polyimide, polyester
• CPC Class Codes: H01L 2224/83851 : being an anisotropic conductive adhesive
• CPC Class Codes: H01L 2224/8391 : Cleaning, e.g. oxide removal step, desmearing
• CPC Class Codes: H01L 2224/84801 : Soldering or alloying
• CPC Class Codes: H01L 2224/84815 : Reflow soldering
• CPC Class Codes: H01L 2224/8485 : using a polymer adhesive, e.g. an adhesive based on silicone, epoxy, polyimide, polyester
• CPC Class Codes: H01L 2224/8491 : Cleaning, e.g. oxide removal step, desmearing
• CPC Class Codes: H01L 2224/85 : using a wire connector
• CPC Class Codes: H01L 2224/9221 : Parallel connecting processes
• CPC Class Codes: H01L 2224/92246 : the second connecting process involving a strap connector
• CPC Class Codes: H01L 2224/92252 : the first connecting process involving a strap connector
• CPC Class Codes: H01L 23/3107 : the device being completely enclosed
• CPC Class Codes: H01L 23/3157 : Partial encapsulation or coating mask layer used as insulation layer H01L21/31
• CPC Class Codes: H01L 23/49513 : having bonding material between chip and die pad
• CPC Class Codes: H01L 23/49524 : the additional leads being a tape carrier or flat leads
• CPC Class Codes: H01L 23/49541 : Geometry of the lead-frame
• CPC Class Codes: H01L 23/49568 : specifically adapted to facilitate heat dissipation
• CPC Class Codes: H01L 23/49575 : Assemblies of semiconductor devices on lead frames
• CPC Class Codes: H01L 23/49844 : for devices being provided for in H01L29/00
• CPC Class Codes: H01L 23/544 : Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps test patterns for characterising or monitoring manufacturing processes H01L22/00
• CPC Class Codes: H01L 24/27 : Manufacturing methods
• CPC Class Codes: H01L 24/29 : of an individual layer connector
• CPC Class Codes: H01L 24/32 : of an individual layer connector
• 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 24/41 : of a plurality of strap connectors
• 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 24/73 : 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 24/83 : using a layer connector
• CPC Class Codes: H01L 24/84 : using a strap connector
• CPC Class Codes: H01L 24/85 : using a wire connector wire bonding in general B23K20/004
• CPC Class Codes: H01L 24/92 : Specific sequence of method steps
• CPC Class Codes: H01L 25/074 : Stacked arrangements of non-apertured devices
• 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 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/0665 : Epoxy resin
• CPC Class Codes: H01L 2924/07811 : Extrinsic, i.e. with electrical conductive fillers
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/1306 : Field-effect transistor [FET]
• CPC Class Codes: H01L 2924/13091 : Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 2924/181 : Encapsulation

Abstract

In one embodiment, a method can include coupling a gate and a source of a first die to a lead frame. The first die can include the gate and the source that are located on a first surface of the first die and a drain that is located on a second surface of the first die that is opposite the first surface. In addition, the method can include coupling a source of a second die to the drain of the first die. The second die can include a gate and a drain that are located on a first surface of the second die and the source that is located on a second surface of the second die that is opposite the first surface.

Claims

1. A method comprising:

attaching a gate and a source of a first die to a lead frame, said first die comprising said gate and said source that are located on a first surface of said first die and a drain that is located on a second surface of said first die that is opposite said first surface;

coupling a source of a second die to said drain of said first die, said second die comprising a gate and a drain that are located on a first surface of said second die and said source that is located on a second surface of said second die that is opposite said first surface;

attaching a clip to said lead frame and said drain of said second die, said clip comprising a first platform, a second platform, and a sloped portion located between said first platform and said second platform, said first platform is located above said second platform;

performing a molding process comprising covering said first die, second die, and clip with a molding material, said molding process comprises using a flexible film so a portion of an upper surface of said clip is free of said molding material, said molding process further comprises using a molding tool comprising a mold surface capable of contacting said upper surface of said clip; and

preventing said portion of said upper surface of said clip from being plated during a plating process, said portion of said upper surface of said clip is exposed in final package.

2. The method of claim 1, further comprising:

coupling said lead frame and said gate of said second die.

3. The method of claim 1, wherein said attaching said clip occurs after said coupling said source of said second die.

4. The method of claim 1, wherein said first die comprising trench gate technology.

5. The method of claim 1, further comprising:

coupling a second clip to said lead frame, said drain of said first die, and to said source of said second die.

6. The method of claim 5, further comprising:

coupling a third clip to said lead frame and said gate of said second die.

7. The method of claim 5, wherein said attaching said clip occurs after said coupling said second clip.

8. The method of claim 6, wherein said attaching said clip occurs at the same time as said coupling said third clip.

9. A method comprising:

attaching a gate and a source of a first die to a lead frame with solder paste, said first die comprising said gate and said source that are located on a first surface of said first die and a drain that is located on a second surface of said first die that is opposite said first surface, said first die comprising split gate technology;

coupling a source of a second die to said drain of said first die, said second die comprising a gate and a drain that are located on a first surface of said second die and said source that is located on a second surface of said second die that is opposite said first surface;

attaching a clip to said lead frame and said drain of said second die with solder paste, said clip comprising a first platform, a second platform, and a sloped portion located between said first platform and said second platform said first platform is located above said second platform;

performing a molding process comprising covering said first die, second die, and clip with a molding material, said molding process comprises using a flexible film so a portion of an upper surface of said clip is free of said molding material, said molding process further comprises using a molding tool comprising a mold surface capable of contacting said upper surface of said clip; and

preventing said portion of said upper surface of said clip from being plated during a plating process, said portion of said upper surface of said clip is exposed in final package.

10. The method of claim 9, wherein said attaching said clip occurs after said coupling said source of said second die.

11. The method of claim 9, further comprising:

coupling said lead frame and said gate of said second die.

12. The method of Claim 9, further comprising:

before said preventing, coupling a second clip to said lead frame and said gate of said second die.

13. The method of claim 9, wherein said clip comprises an electrically conductive material.

14. The method of claim 9, further comprising:

coupling a second clip to said lead frame, said drain of said first die, and to said source of said second die.

15. The method of claim 9, wherein said preventing comprises using a film.

16. A method comprising:

attaching a gate and a source of a first die to a lead frame with conductive adhesive, said first die comprising said gate and said source that are located on a first surface of said first die and a drain that is located on a second surface of said first die that is opposite said first surface, said first die comprising split gate technology;

coupling a source of a second die to said drain of said first die, said second die comprising a gate and a drain that are located on a first surface of said second die and said source that is located on a second surface of said second die that is opposite said first surface;

attaching a clip to said lead frame and said drain of said second die with conductive adhesive, said clip comprising a first platform, a second platform, and a sloped portion located between said first platform and said second platform, said first platform is located above said second platform;

performing a molding process comprising covering said first die, second die, and clip with a molding material, said molding process comprises using a flexible film so a portion of an upper surface of said clip is free of said molding material, said molding process further comprises using a molding tool comprising a mold surface capable of contacting said upper surface of said clip; and

preventing said portion of said upper surface of said clip from being plated during a plating process, said portion of said upper surface of said clip is exposed in final package.

17. The method of claim 16, wherein said attaching said clip occurs of said coupling said source of said second die.

18. The method of claim 16, coupling a second clip to said lead frame and said gate of said second die.

19. The method of claim 18, wherein said clip and said second clip each comprises an electrically conductive material.

20. The method of claim 16, further comprising:

coupling a second clip to said lead frame, said drain of said first die, and to said source of said second die.