Underfill and encapsulation of semicondcutor assemblies with materials having differing properties and methods of fabrication using stereolithography

• US 20050277231A1
• Filed: 06/14/2004
• Published: 12/15/2005
• Est. Priority Date: 06/14/2004
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Farnworth, Warren M., Hembree, David R.
• Granted Patent: US 7,547,978 B2
• Time in Patent Office: Days
• US Class Current: 438/127
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: H01L 21/563 Encapsulation of active face of flip-chip device, e.g. underfilling or underencapsulation of flip-chip, encapsulation preform on chip or mounting substrate
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/1147 using a lift-off mask
• CPC Class Codes: H01L 2224/13016 in side view
• CPC Class Codes: H01L 2224/1329 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/13386 with a principal constituent of the material being a non metallic, non metalloid inorganic material
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/16237 the bump connector connecting to a bonding area disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/27554 Stereolithography, i.e. solidification of a pattern defined by a laser trace in a photosensitive resin
• CPC Class Codes: H01L 2224/2908 being stacked
• 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 2224/293 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 2224/29386 with a principal constituent of the material being a non metallic, non metalloid inorganic material
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/73104 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/73203 Bump and layer connectors
• CPC Class Codes: H01L 2224/73204 : the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/81136 : involving guiding structures, e.g. spacers or supporting members
• CPC Class Codes: H01L 2224/81192 : wherein the bump connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/8121 : using a reflow oven
• CPC Class Codes: H01L 2224/81815 : Reflow soldering
• CPC Class Codes: H01L 2224/81855 : Hardening the adhesive by curing, i.e. thermosetting
• CPC Class Codes: H01L 2224/81903 : by means of a layer connector
• 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 2224/83194 : Lateral distribution of the layer connectors
• CPC Class Codes: H01L 2224/83851 : being an anisotropic conductive adhesive
• CPC Class Codes: H01L 2224/90 : Methods for connecting semiconductor or solid state bodies using means for bonding not being attached to, or not being formed on, the body surface to be connected, e.g. pressure contacts using springs or clips
• CPC Class Codes: H01L 23/295 : containing a filler H01L23/296 takes precedence
• CPC Class Codes: H01L 23/552 : Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 24/13 : of an individual bump connector
• CPC Class Codes: H01L 24/27 : Manufacturing methods
• CPC Class Codes: H01L 24/29 : of an individual layer connector
• CPC Class Codes: H01L 24/743 : Apparatus for manufacturing layer connectors
• CPC Class Codes: H01L 24/81 : using a bump connector
• CPC Class Codes: H01L 24/83 : using a layer connector
• CPC Class Codes: H01L 24/90 : Methods for connecting semiconductor or solid state bodies using means for bonding not being attached to, or not being formed on, the body surface to be connected, e.g. pressure contacts using springs or clips
• CPC Class Codes: H01L 27/14618 : Containers
• CPC Class Codes: H01L 27/1462 : Coatings
• 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 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01018 : Argon [Ar]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/0106 : Neodymium [Nd]
• CPC Class Codes: H01L 2924/01075 : Rhenium [Re]
• CPC Class Codes: H01L 2924/01077 : Iridium [Ir]
• CPC Class Codes: H01L 2924/0503 : 13th Group
• CPC Class Codes: H01L 2924/0665 : Epoxy resin
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H01L 2924/351 : Thermal stress
• CPC Class Codes: H01L 2924/3512 : Cracking

Abstract

Polymerized materials for forming the underfill and encapsulation structures for semiconductor package are disclosed. A filler constituent, such as boron nitride, silicates, elemental metals, or alloys, may be added to a liquid photopolymer resin to tailor the physical properties thereof upon curing. The filler constituents may be employed to alter the coefficient of thermal expansion, thermal conductivity, or electrical conductivity of the polymerized material. A number of different embodiments are disclosed that employ the above materials in selected regions of the underfill and encapsulation structures of the semiconductor package. The polymerized materials may also be used to form support structures and covers for optically interactive semiconductor devices. Methods for forming the above structures using stereolithography are also disclosed.

Claims

1. A semiconductor device assembly comprising:

at least one semiconductor die having lateral sides, a back side, and an active surface including a plurality of discrete conductive elements projecting therefrom; and

a carrier substrate bearing a plurality of conductive traces in electrical communication with the plurality of discrete conductive elements;

wherein at least a portion of the semiconductor device assembly is covered with a first cured photopolymer material, wherein the first cured photopolymer material comprising a polymerized matrix having a plurality of discrete particles dispersed therethrough.

2. The semiconductor device assembly of claim 1, wherein the first cured photopolymer material substantially fills a volume between the at least one semiconductor die and the carrier substrate.

3. The semiconductor device assembly of claim 2, wherein the first cured photopolymer material substantially encloses the at least one semiconductor die.

4. The semiconductor device assembly of claim 3, wherein the discrete particles comprise boron nitride.

5. The semiconductor device assembly of claim 1, wherein the first cured photopolymer material covers the back side of the at least one semiconductor die and a second cured photopolymer material substantially fills a volume between the at least one semiconductor die and the carrier substrate and surrounds a lateral periphery of the at least one semiconductor die to form a contiguous structure with the first cured photopolymer material.

6. The semiconductor device assembly of claim 5, wherein the first cured photopolymer material exhibits a thermal conductivity greater than that of the second cured photopolymer material.

7. The semiconductor device assembly of claim 6, wherein the discrete particles comprise boron nitride.

8. The semiconductor device assembly of claim 1, further comprising:

a second cured photopolymer material that substantially fills a volume between the at least one semiconductor die and the carrier substrate; and

wherein the first cured photopolymer material at least partially encloses the at least one semiconductor die including the second photopolymerized material.

9. The semiconductor device assembly of claim 8, wherein the first cured photopolymer material exhibits an electrical conductivity greater than an electrical conductivity of the second cured photopolymer material.

10. The semiconductor device assembly of claim 9, wherein the discrete particles of the first cured photopolymer material comprise an elemental metal or an alloy.

11. The semiconductor device assembly of claim 1, wherein the first cured photopolymer material substantially fills a volume between the at least one semiconductor die and the carrier substrate, the first cured photopolymer material exhibiting a gradient in coefficient of thermal expansion that increases in a direction from the active surface of the at least one semiconductor die to a face of the carrier substrate.

12. The semiconductor device assembly of claim 11, wherein the first cured photopolymer material is comprised of more than one layer, each layer having a different concentration of the discrete particles.

13. The semiconductor device assembly of claim 11, wherein the discrete particles comprise boron nitride or a silicate material.

14. The semiconductor device assembly of claim 11, further comprising a second cured photopolymer material that covers the back side and at least a portion of the lateral sides of the at least one semiconductor die.

15. The semiconductor device assembly of claim 14, wherein the second cured photopolymer material comprises a polymerized matrix having a plurality of discrete particles dispersed therethrough.

16. The semiconductor device assembly of claim 15, wherein the discrete particles of the second cured photopolymer material comprise boron nitride.

17. The semiconductor assembly of claim 16, further comprising a third cured photopolymer material comprising a polymerized matrix having a plurality of discrete particles dispersed therethrough at least partially enclosing the at least one semiconductor die including the first and the second cured photopolymer materials, wherein the third cured photopolymer material exhibits an electrical conductivity greater than an electrical conductivity of each of the first and the second cured photopolymer materials.

18. A method of forming a semiconductor package, comprising:

providing a carrier substrate bearing a plurality of conductive traces;

securing at least one semiconductor die having lateral sides, a back side, and an active surface including a plurality of discrete conductive elements projecting therefrom by the plurality of discrete conductive elements to the conductive traces of the carrier substrate to form a semiconductor device assembly;

immersing the semiconductor device assembly in a first liquid photopolymerizable resin including a plurality of discrete particles dispersed therethrough; and

selectively at least partially curing portions of the first liquid photopolymerizable resin adjacent the at least one semiconductor die.

19. The method according to claim 18, further comprising at least partially curing portions of the first liquid photopolymerizable resin to form an underfill structure that substantially fills a volume between the at least one semiconductor die and the carrier substrate.

20. The method according to claim 19, further comprising submerging the semiconductor assembly to a depth wherein the first liquid photopolymerizable resin overlies the at least one semiconductor die and at least partially curing the first liquid photopolymerizable resin to fully enclose the at least one semiconductor die.

21. The method according to claim 20, further comprising selecting the discrete particles to comprise boron nitride.

22. The method according to claim 18, further comprising:

immersing the semiconductor device assembly in a second liquid photopolymerizable resin prior to immersion in and selectively at least partially curing portions of the first liquid photopolymerizable resin;

at least partially curing the second liquid photopolymerizable resin within a volume between the at least one semiconductor die and the carrier substrate and a lateral periphery surrounding the at least one semiconductor die to form an underfill structure; and

at least partially curing portions of the first liquid photopolymerizable resin to form a cover structure that covers the back side of the at least one semiconductor die and is contiguous with the underfill structure.

23. The method according to claim 22, further comprising selecting the discrete particles to comprise boron nitride.

24. The method according to claim 22, further comprising immersing the semiconductor device assembly in a third liquid photopolymerizable resin and at least partially curing portions of the third liquid photopolymerizable resin to at least partially enclose the at least one semiconductor die, the underfill structure, and the cover structure.

25. The method according to claim 24, further comprising selecting the third liquid photopolymerizable resin to include a plurality of discrete particles comprising an elemental metal or an alloy.

26. The method according to claim 18, further comprising:

immersing the semiconductor device assembly in a second liquid photopolymerizable resin prior to immersion in and selectively at least partially curing portions of the first liquid photopolymerizable resin;

at least partially curing the second liquid photopolymerizable resin within a volume between the at least one semiconductor die and the carrier substrate and a lateral periphery surrounding the at least one semiconductor die to form an underfill structure; and

at least partially curing portions of the first liquid photopolymerizable resin to surround a lateral periphery of the at least one semiconductor die and be contiguous with the underfill structure.

27. The method according to claim 26, further comprising selecting the discrete particles to comprise an elemental metal or an alloy.

28. The method according to claim 18, further comprising:

wherein the selectively at least partially curing portions of the first liquid photopolymerizable resin comprises forming a first layer thereof on the carrier substrate located in a region between the carrier substrate and the at least one semiconductor die;

immersing the semiconductor device assembly in at least one additional liquid photopolymerizable resin including a plurality of discrete particles to cause the at least one additional liquid photopolymerizable resin to fill a volume between the at least one semiconductor die and the first layer; and

selectively at least partially curing portions of the at least one additional liquid photopolymerizable resin to form a second layer contiguous with the first layer.

29. The method according to claim 28, further comprising formulating the at least one additional liquid photopolymerizable resin including a plurality of discrete particles to cause the second layer to have a coefficient of thermal expansion less than that of the first layer.

30. The method according to claim 29, further comprising selecting the discrete particles to comprise boron nitride or a silicate.

31. A method of forming a semiconductor package comprising:

providing a carrier substrate having a plurality of conductive traces;

immersing the carrier substrate in a first liquid photopolymerizable resin to cover the carrier substrate with a layer thereof, the first liquid photopolymerizable resin having a first coefficient of thermal expansion in a cured state;

selectively at least partially curing the layer of the first liquid photopolymerizable resin to form a first layer exposing at least a portion of the plurality of the conductive traces through a plurality of apertures;

depositing a conductive material in the plurality of apertures;

securing at least one semiconductor die including a plurality of discrete conductive elements to the carrier substrate to form a semiconductor device assembly, the plurality of discrete conductive elements in electrical communication with the plurality of conductive traces of the carrier substrate;

immersing the semiconductor device assembly in a second liquid photopolymerizable resin, the second liquid photopolymerizable resin having a second coefficient of thermal expansion in a cured state less than the first coefficient of thermal expansion; and

selectively at least partially curing the second liquid photopolymerizable resin to form a second layer that fills at least a portion of a region between the first layer and the at least one semiconductor die and substantially seals the at least one semiconductor die.

32. The method according to claim 31, further comprising, prior to depositing the conductive material in the plurality of apertures, forming one or more additional layers from a cured photopolymer material, wherein the one or more additional layers and the first layer exhibit a gradient in coefficient of thermal expansion that decreases in a direction from the first layer toward the one or more additional layers.

33. The method according to claim 31, further comprising curing the first layer and the second layer to form a unitary structure.

34. The method according to claim 32, further comprising curing the first layer, the second layer, and the one or more additional layers to form a unitary structure.

35. The method according to claim 31, further comprising selecting the second layer to have a concentration of discrete particles that is greater than a concentration of discrete particles of the first layer.

36. The method according to claim 35, further comprising selecting the discrete particles to comprise boron nitride or a silicate.

37. A semiconductor package comprising:

at least one semiconductor die having an active surface including an array of optically interactive semiconductor devices; and

a substantially opaque support structure that surrounds the array of optically interactive semiconductor devices formed from a first cured photopolymer material.

38. The semiconductor package of claim 37, further comprising a second cured, optically transparent photopolymer material that covers the array of optically interactive semiconductor devices.

39. The semiconductor package of claim 38, wherein the second cured, optically transparent photopolymer material substantially filters infrared radiation.

40. The semiconductor package of claim 39, further comprising at least one lens supported by the support structure over the array of optically interactive semiconductor devices.

41. The semiconductor package of claim 37, further comprising at least one lens supported by the support structure.

42. The semiconductor package of claim 41, further comprising an infrared filter disposed between the active surface and the at least one lens.

43. The semiconductor package of claim 37, wherein the first cured photopolymer material comprises a polymerized matrix including a plurality of discrete particles dispersed therethrough.

44. The semiconductor package of claim 43, wherein the discrete particles of the first cured photopolymer material comprise an elemental metal or an alloy.

45. A method of forming a semiconductor package, comprising:

providing at least one semiconductor die having an active surface including an array of optically interactive semiconductor devices;

immersing the at least one semiconductor die in a first liquid photopolymerizable resin; and

selectively at least partially curing portions of the first liquid photopolymerizable resin surrounding a periphery of the array to form a substantially opaque support structure.

46. The method according to claim 45, further comprising:

immersing the at least one semiconductor die in a second liquid photopolymerizable resin; and

selectively at least partially curing portions of the second liquid photopolymerizable resin covering the array.

47. The method according to claim 46, further comprising fixing at least one lens to the support structure over the array.

48. The method according to claim 45, further comprising fixing at least one lens to the support structure.

49. The method according to claim 48, further comprising disposing an infrared filter between the at least one lens and the active surface.

50. The method according to claim 45, further comprising formulating the first liquid photopolymerizable resin to include a plurality of discrete particles.