Semiconductor radiation emitter package

• US 7,253,448 B2
• Filed: 12/06/2004
• Issued: 08/07/2007
• Est. Priority Date: 03/15/1999
• Status: Expired due to Term

• Current Assignee: Everlight Electronics Company Limited
• Original Assignee: Gentex Corporation
• Inventors: Roberts, John K., Turnbull, Robert R., Stam, Joseph S., Reese, Spencer D.
• Primary Examiner(s): Ha; Nathan W.
• Application Number:
  US11/005,459
• Publication Number:
  US 20050077623A1
• Time in Patent Office: 974 Days
• Field of Search: 257 99-100, 257/98, 257431-434, 372/26
• US Class Current: 257/99
• CPC Class Codes: H01L 2224/04042 Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/05624 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/05639 Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/05644 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/05647 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/32245 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 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 2224/48624 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/48639 Silver (Ag) as principal constituent
• CPC Class Codes: H01L 2224/48644 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48647 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/48724 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/48739 Silver (Ag) as principal constituent
• CPC Class Codes: H01L 2224/48744 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48747 : Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/49171 : Fan-out arrangements
• CPC Class Codes: H01L 2224/73265 : Layer and wire connectors
• CPC Class Codes: H01L 23/49562 : for devices being provided for in H01L29/00
• CPC Class Codes: H01L 24/05 : of an individual bonding area
• 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 24/73 : 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 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 2924/01004 : Beryllium [Be]
• 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 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/0102 : Calcium [Ca]
• CPC Class Codes: H01L 2924/01023 : Vanadium [V]
• 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 2924/0103 : Zinc [Zn]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01041 : Niobium [Nb]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01068 : Erbium [Er]
• CPC Class Codes: H01L 2924/01073 : Tantalum [Ta]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01075 : Rhenium [Re]
• CPC Class Codes: H01L 2924/01077 : Iridium [Ir]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/01088 : Radium [Ra]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/09701 : Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/10329 : Gallium arsenide [GaAs]
• CPC Class Codes: H01L 2924/10336 : Aluminium gallium arsenide [AlGaAs]
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/12044 : OLED
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/351 : Thermal stress
• CPC Class Codes: H01L 2933/0091 : Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/54 : having a particular shape
• CPC Class Codes: H01L 33/62 : Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01L 33/642 : characterized by the shape
• CPC Class Codes: H01L 33/647 : the elements conducting electric current to or from the semiconductor body
• CPC Class Codes: H10K 50/84 : Passivation; Containers; Encapsulations
• CPC Class Codes: H10K 50/85 : Arrangements for extracting light from the devices
• CPC Class Codes: H10K 50/87 : Arrangements for heating or cooling

Abstract

A semiconductor optical radiation package includes a leadframe, at least one semiconductor optical radiation emitter, and an encapsulant. The leadframe has a heat extraction member, which supports the semiconductor optical emitter and provides one or more thermal paths for removing heat generated within the emitter to the ambient environment, as well as at least two electrical leads for providing electrical coupling to the semiconductor optical radiation emitter. The encapsulant covers and protects the emitter and optional wire bonds from damage and allows radiation to be emitted from the emitter into the ambient environment. The semiconductor optical radiation package provides high emitted flux and is preferably compatible with automated processing techniques.

Claims

1. A semiconductor radiation emitter package comprising:

a heat extraction element;

at least two electrical leads having a greater thermal resistance than said heat extraction element;

at least one semiconductor radiation emitter mounted on a first surface of said heat extraction element, wherein when said at least one semiconductor radiation emitter is activated, the semiconductor radiation emitter package emits white light; and

an encapsulant covering said at least one semiconductor radiation emitter, at least a portion of said encapsulant being substantially transparent to wavelengths emitted by said at least one semiconductor radiation emitter, said encapsulant material covering a portion of the first surface of said heat extraction element, while leaving exposed at least a portion of a second surface of said heat extraction element that is opposite the first surface, the exposed portion of the second surface being directly opposite an area of the first surface where said at least one semiconductor radiation emitter is mounted.

2. The semiconductor radiation emitter package of claim 1, wherein the exposed portion of the heat extraction member includes a region generally directly opposite a location on the first surface where said at least one semiconductor radiation emitter is mounted, and wherein said heat extraction member provides a primary thermal path out of the device from said at least one semiconductor radiation emitter and said electrical leads provide a secondary thermal path out of the device from said at least one semiconductor radiation emitter, said secondary thermal path possessing thermal resistance greater than said primary thermal path.

3. The semiconductor radiation emitter package of claim 1, wherein said heat extraction element has a thickness in a direction that is substantially parallel to the direction in which radiation is emitted from the semiconductor radiation emitter package that is greater than the thickness of said electrical leads.

4. The semiconductor radiation emitter package of claim 1, wherein said encapsulant comprises a first hard molding compound and a second hard molding compound, said first hard molding compound is substantially transparent to radiation emitted by said at least one semiconductor radiation emitter and is provided within the optical path of radiation emitted from said at least one semiconductor radiation emitter.

5. The semiconductor radiation emitter package of claim 4, wherein said second hard molding compound covers a portion of the first surface of said heat extraction element, while leaving exposed at least a portion of a second surface of said heat extraction element that is opposite the first surface, the exposed portion of the second surface being directly opposite an area of the first surface where said at least one semiconductor radiation emitter is mounted.

6. The semiconductor radiation emitter package of claim 5, wherein said second hard molding compound is substantially opaque.

7. The semiconductor radiation emitter package of claim 1, wherein the heat extraction member comprises a depression containing the at least one semiconductor radiation emitter.

8. The semiconductor radiation emitter package of claim 7, wherein the depression is coated with an optically reflective coating.

9. The semiconductor radiation emitter package of claim 1, wherein the heat extraction member comprises at least one of fins, slots, and holes to increase surface area outside the portion of the heat extraction member covered with the encapsulant.

10. The semiconductor radiation emitter package of claim 1, wherein a portion of the encapsulant is formed as a lens.

11. The semiconductor radiation emitter package of claim 1, wherein the encapsulant comprises a filler component and a bulk component, the filler component lowering the thermal coefficient of expansion of the bulk component, the filler component having an index of refraction nearly matching the index of refraction of the bulk component.

12. The semiconductor radiation emitter package of claim 1, wherein the encapsulant comprises a filler component operative to diffuse semiconductor radiation emitter output radiation.

13. The semiconductor radiation emitter package of claim 1, wherein the semiconductor radiation emitter comprises a conductive base in electrical contact with the heat extraction member.

14. The semiconductor radiation emitter package of claim 1, wherein the at least one semiconductor radiation emitter comprises a light emitting diode.

15. The semiconductor radiation emitter package of claim 1, wherein the at least one semiconductor radiation emitter comprises a light emitting polymer.

16. The semiconductor radiation emitter package of claim 1 and further comprising a fluorescent material.

17. The semiconductor radiation emitter package of claim 1 further comprising a heat sink in thermal contact with the heat extraction member.

18. The semiconductor radiation emitter package of claim 1, wherein:

said encapsulant forms a plurality of sides;

each of said electrical leads extends through one of a first set of encapsulant sides; and

said heat extraction member extends through at least one of a second set of encapsulant sides, the second set of encapsulant sides is different from the first set of encapsulant sides.

19. The semiconductor radiation emitter package of claim 18, wherein the first set of encapsulant sides comprises a first side and the second set of encapsulant sides comprises a second side opposite the first side.

20. The semiconductor radiation emitter package of claim 18, wherein the first set of encapsulant sides comprises opposing sides.

21. The semiconductor radiation emitter package of claim 18, wherein the second set of encapsulant sides comprises opposing sides.

22. The semiconductor radiation emitter package of claim 1, wherein at least two of said electrical leads are retained by said encapsulant.

23. The semiconductor radiation emitter package of claim 1, wherein said encapsulant covers a portion of said heat extraction member equal to or less than 65% of the total surface area of said heat extraction member.

24. The semiconductor radiation emitter package of claim 1, wherein the bulk of said electrical leads and said heat extraction member are composed substantially of the same material.

25. The semiconductor radiation emitter package of claim 1, wherein said at least one semiconductor radiation emitter includes two semiconductor radiation emitters that emit illumination having binary complementary hues that may mix to form white light.

26. The semiconductor radiation emitter package of claim 1, wherein said at least one semiconductor radiation emitter includes three semiconductor radiation emitters that emit illumination having ternary complementary hues that may mix to form white light.

27. The semiconductor radiation emitter package of claim 26, wherein a first one of said three semiconductor radiation emitters emits illumination having a red hue, a second one of said three semiconductor radiation emitters emits illumination having a green hue, and a third one of said three semiconductor radiation emitters emits illumination having a blue hue.

28. The semiconductor radiation emitter package of claim 1, wherein the semiconductor radiation emitter package has a power capacity of at least about 150 mW.

29. The semiconductor radiation emitter package of claim 1, and further comprising at least one recessed optically reflective cup formed in the heat extraction member, said at least one semiconductor radiation emitter being mounted within said at least one recessed optically reflective cup, wherein the depth of said at least one recessed optically reflective cup is equal to or greater than the height of said at least one semiconductor radiation emitter, each measured in the dimension parallel to the optical axis of the reflective cup within which said at least one semiconductor radiation emitter is mounted.

30. The semiconductor radiation emitter package of claim 1, wherein a cross-sectional area of said heat extraction element measured in a plane normal to the path between the at least one semiconductor radiation emitter and the nearest unencapsulated surface of said heat extraction element is greater than a cross-sectional area of each of said electrical leads measured in a plane that is normal to the path of heat flow between said at least one semiconductor radiation emitter and the nearest unencapsulated surface of said electrical leads during operation of the package.

31. The semiconductor radiation emitter package of claim 1, wherein said encapsulant includes a top surface through which radiation from said at least one semiconductor radiation emitter is emitted and further including a bottom surface, opposite said top surface, said encapsulant is formed to allow the exposed portion of the bottom surface of said heat extraction member to be exposed through the bottom surface of the encapsulant.

32. The semiconductor radiation emitter package of claim 1, wherein said heat extraction member is made of a material having a substantially high thermal conductivity.

33. The semiconductor radiation emitter package of claim 32, wherein said material is selected from the group consisting of a ceramic material, copper, copper alloys, aluminum, soft steel, or other metal.

34. The semiconductor radiation emitter package of claim 1, wherein the thermal path from said semiconductor radiation emitter to the exposed portion of the bottom surface of said heat extraction member is shorter than the thermal path from said semiconductor radiation emitter to a location where said electrical leads emerge from said encapsulant.

35. The semiconductor radiation emitter package of claim 1, wherein the exposed portion of said heat extraction member is coated with a coating material having improved thermal emissivity.

36. The semiconductor radiation emitter package of claim 35, wherein said coating material is selected from the group consisting of nichrome and black-oxide.

37. The semiconductor radiation emitter package of claim 1, wherein the exposed portion of said heat extraction member is textured.

38. The semiconductor radiation emitter package of claim 37, wherein the exposed portion of said heat extraction member has a matte finish.

39. The semiconductor radiation emitter package of claim 1, wherein the exposed portion of the heat extraction member includes a region opposite the primary direction of optical radiation emission from said at least one semiconductor radiation emitter.

40. The semiconductor radiation emitter package of claim 1, wherein said encapsulant comprises two different materials.

41. The semiconductor radiation emitter package of claim 40, wherein one of said two different materials is a transparent epoxy.

42. The semiconductor radiation emitter package of claim 40, wherein one of said two different materials is a stress relieving gel.

43. The semiconductor radiation emitter package of claim 42, wherein the stress relieving gel is silicone.

44. The semiconductor radiation emitter package of claim 42, wherein the stress relieving gel is applied over said at least one semiconductor radiation emitter.

45. The semiconductor radiation emitter package of claim 44, wherein one of said two different materials is a hard molding compound that is formed over the stress relieving gel.

46. The semiconductor radiation emitter package of claim 45, wherein said hard molding compound is epoxy.

47. The semiconductor radiation emitter package of claim 40, wherein said two different materials include a first hard molding compound and a second hard molding compound.

48. The semiconductor radiation emitter package of claim 47, wherein said first hard molding compound is substantially transparent to radiation emitted by said at least one semiconductor radiation emitter.

49. The semiconductor radiation emitter package of claim 48, wherein said first hard molding compound is provided within an optical path of said at least one semiconductor radiation emitter and is shaped to define a lens.

50. The semiconductor radiation emitter package of claim 49, wherein said second hard molding compound is provided in regions not within the optical path of said at least one semiconductor radiation emitter.

51. The semiconductor radiation emitter package of claim 50, wherein said second hard molding component is substantially opaque.

52. The semiconductor radiation emitter package of claim 47, wherein said second hard molding compound is provided where said encapsulant retains said electrical leads.

53. The semiconductor radiation emitter package of claim 1, wherein said encapsulant is molded directly onto a portion of said heat extraction element.

54. The semiconductor radiation emitter package of claim 1, wherein said encapsulant defines a plurality of sides and said heat extraction element extends out through two of said sides.

55. The semiconductor radiation emitter package of claim 47, wherein said second hard molding compound defines a plurality of sides and said heat extraction element extends out through two of said sides.

56. The semiconductor radiation emitter package of claim 1, wherein said encapsulant is made of a single transparent material.

57. A semiconductor radiation emitter package comprising:

a heat extraction element;

at least two electrical leads having a greater thermal resistance than said heat extraction element;

at least one semiconductor radiation emitter mounted on a first surface of said heat extraction element, wherein when said at least one semiconductor radiation emitter is activated, the semiconductor radiation emitter package emits white light; and

a first hard molding compound and a second hard molding compound, said first hard molding compound is substantially transparent to radiation emitted by said at least one semiconductor radiation emitter and is provided within the optical path of radiation emitted from said at least one semiconductor radiation emitter, wherein said second hard molding compound covers a portion of the first surface of said heat extraction element, while leaving exposed at least a portion of a second surface of said heat extraction element that is opposite the first surface, the exposed portion of the second surface being directly opposite an area of the first surface where said at least one semiconductor radiation emitter is mounted.

58. The semiconductor radiation emitter package of claim 57, wherein said heat extraction element having a thickness in a direction that is substantially parallel to the direction in which radiation is emitted from the semiconductor radiation emitter package that is greater than the thickness of said electrical leads.

59. The semiconductor radiation emitter package of claim 57 and further comprising a second hard molding compound covering a portion of said heat extraction element, while leaving exposed a portion of said heat extraction element, said second hard molding compound being different from said first hard molding compound and encapsulating a portion of said electrical leads so as to retain said electrical leads.

60. The semiconductor radiation emitter package of claim 57, wherein the heat extraction member comprises a depression containing the at least one semiconductor radiation emitter.

61. The semiconductor radiation emitter package of claim 60, wherein the depression is coated with an optically reflective coating.

62. The semiconductor radiation emitter package of claim 57, wherein the heat extraction member comprises at least one of fins, slots, and holes to increase surface area outside the portion of the heat extraction member covered with the encapsulant.

63. The semiconductor radiation emitter package of claim 57, wherein a portion of the first hard molding compound is formed as a lens.

64. The semiconductor radiation emitter package of claim 57, wherein the encapsulant comprises a filler component and a bulk component, the filler component lowering the thermal coefficient of expansion of the bulk component, the filler component having an index of refraction nearly matching the index of refraction of the bulk component.

65. The semiconductor radiation emitter package of claim 57, wherein the semiconductor radiation emitter comprises a conductive base in electrical contact with the heat extraction member.

66. The semiconductor radiation emitter package of claim 57, wherein the at least one semiconductor radiation emitter comprises a light emitting diode.

67. The semiconductor radiation emitter package of claim 57 and further comprising a fluorescent material.

68. The semiconductor radiation emitter package of claim 57, wherein the bulk of said electrical leads and said heat extraction member are composed substantially of the same material.

69. The semiconductor radiation emitter package of claim 57, wherein said at least one semiconductor radiation emitter includes two semiconductor radiation emitters that emit illumination having binary complementary hues that may mix to form white light.

70. The semiconductor radiation emitter package of claim 57, wherein said at least one semiconductor radiation emitter includes three semiconductor radiation emitters that emit illumination having ternary complementary hues that may mix to form white light.

71. The semiconductor radiation emitter package of claim 57, wherein the semiconductor radiation emitter package has a power capacity of at least about 150 mW.

72. The semiconductor radiation emitter package of claim 57, and further comprising at least one recessed optically reflective cup formed in the heat extraction member, said at least one semiconductor radiation emitter being mounted within said at least one recessed optically reflective cup, wherein the depth of said at least one recessed optically reflective cup is equal to or greater than the height of said at least one semiconductor radiation emitter, each measured in the dimension parallel to the optical axis of the reflective cup within which said at least one semiconductor radiation emitter is mounted.

73. A semiconductor radiation emitter package comprising:

a heat extraction element;

at least two electrical leads having a greater thermal resistance than said heat extraction element, said heat extraction element having a thickness in a direction that is substantially parallel to the direction in which radiation is emitted from the semiconductor radiation emitter package that is greater than the thickness of said electrical leads;

at least one semiconductor radiation emitter mounted on said heat extraction element, wherein when said at least one semiconductor radiation emitter is activated, the semiconductor radiation emitter package emits white light; and

a first hard molding compound covering said at least one semiconductor radiation emitter, at least a portion of said first hard molding compound being substantially transparent to wavelengths emitted by said at least one semiconductor radiation emitter.

74. The semiconductor radiation emitter package of claim 73, wherein said first hard molding compound is part of an encapsulant that encapsulates said at least one semiconductor radiation emitter.

75. The semiconductor radiation emitter package of claim 73, wherein the thickness of the heat extraction element is at least three times the thickness of the electrical leads.

76. The semiconductor radiation emitter package of claim 73 and further comprising a second hard molding compound covering a portion of said heat extraction element, while leaving exposed a portion of said heat extraction element, said second hard molding compound being different from said first hard molding compound and encapsulating a portion of said electrical leads so as to retain said electrical leads.

77. The semiconductor radiation emitter package of claim 73, wherein said first hard molding compound covers a portion of said heat extraction element and a portion of said electrical leads while leaving portions of both said heat extraction element and said electrical leads uncovered.

78. The semiconductor radiation emitter package of claim 77, wherein a cross-sectional area of said heat extraction element measured in a plane normal to the path between said at least one semiconductor radiation emitter and the nearest uncovered surface of said heat extraction element is greater than a cross-sectional area of each of said electrical leads measured in a plane that is normal to the path of heat flow between said at least one semiconductor radiation emitter and the nearest unencapsulated surface of said electrical leads, during operation of the package.

79. The semiconductor radiation emitter package of claim 73, wherein the heat extraction member comprises a depression containing the at least one semiconductor radiation emitter.

80. The semiconductor radiation emitter package of claim 79, wherein the depression is coated with an optically reflective coating.

81. The semiconductor radiation emitter package of claim 73, wherein a portion of the first hard molding compound is formed as a lens.

82. The semiconductor radiation emitter package of claim 73, wherein the semiconductor radiation emitter comprises a conductive base in electrical contact with the heat extraction member.

83. The semiconductor radiation emitter package of claim 73, wherein the at least one semiconductor radiation emitter comprises a light emitting diode.

84. The semiconductor radiation emitter package of claim 73 and further comprising a fluorescent material.

85. The semiconductor radiation emitter package of claim 73, wherein the bulk of said electrical leads and said heat extraction member are composed substantially of the same material.

86. The semiconductor radiation emitter package of claim 73, wherein said at least one semiconductor radiation emitter includes two semiconductor radiation emitters that emit illumination having binary complementary hues that may mix to form white light.

87. The semiconductor radiation emitter package of claim 73, wherein said at least one semiconductor radiation emitter includes three semiconductor radiation emitters that emit illumination having ternary complementary hues that may mix to form white light.

88. The semiconductor radiation emitter package of claim 73, wherein the semiconductor radiation emitter package has a power capacity of at least about 150 mW.

89. The semiconductor radiation emitter package of claim 73, and further comprising at least one recessed optically reflective cup formed in the heat extraction member, said at least one semiconductor radiation emitter being mounted within said at least one recessed optically reflective cup, wherein the depth of said at least one recessed optically reflective cup is equal to or greater than the height of said at least one semiconductor radiation emitter, each measured in the dimension parallel to the optical axis of the reflective cup within which said at least one semiconductor radiation emitter is mounted.

90. A semiconductor radiation emitter package comprising:

a heat extraction element;

at least two electrical leads having a greater thermal resistance than said heat extraction element;

at least one semiconductor radiation emitter mounted on a first surface of said heat extraction element; and

an encapsulant encapsulating said at least one semiconductor radiation emitter, a portion of said heat extraction element and a portion of said electrical leads, wherein a cross-sectional area of said heat extraction element measured in a plane normal to the path between said at least one semiconductor radiation emitter and the nearest unencapsulated surface of said heat extraction element is greater than a cross-sectional area of each of said electrical leads measured in a plane that is normal to the path of heat flow between said at least one semiconductor radiation emitter and the nearest unencapsulated surface of said electrical leads during operation of the package, wherein said encapsulant defines a plurality of sides and said heat extraction element extends out through two of said sides.

91. The semiconductor radiation emitter package of claim 90, wherein said heat extraction element having a thickness in a direction that is substantially parallel to the direction in which radiation is emitted from the semiconductor radiation emitter package that is greater than the thickness of said electrical leads.

92. The semiconductor radiation emitter package of claim 90, wherein said encapsulant comprises a first hard molding compound and a second hard molding compound, said first hard molding compound is substantially transparent to radiation emitted by said at least one semiconductor radiation emitter and is provided within the optical path of radiation emitted from said at least one semiconductor radiation emitter.

93. The semiconductor radiation emitter package of claim 92, wherein said second hard molding compound covers a portion of the first surface of said heat extraction element, while leaving exposed at least a portion of a second surface of said heat extraction element that is opposite the first surface, the exposed portion of the second surface being directly opposite an area of the first surface where said at least one semiconductor radiation emitter is mounted.

94. The semiconductor radiation emitter package of claim 90, wherein the heat extraction member comprises a depression containing the at least one semiconductor radiation emitter.

95. The semiconductor radiation emitter package of claim 94, wherein the depression is coated with an optically reflective coating.

96. The semiconductor radiation emitter package of claim 90, wherein a portion of the encapsulant is formed as a lens.

97. The semiconductor radiation emitter package of claim 90, wherein the encapsulant comprises a filler component and a bulk component, the filler component lowering the thermal coefficient of expansion of the bulk component, the filler component having an index of refraction nearly matching the index of refraction of the bulk component.

98. The semiconductor radiation emitter package of claim 90, wherein the semiconductor radiation emitter comprises a conductive base in electrical contact with the heat extraction member.

99. The semiconductor radiation emitter package of claim 90, wherein the at least one semiconductor radiation emitter comprises a light emitting diode.

100. The semiconductor radiation emitter package of claim 90 and further comprising a fluorescent material.

101. The semiconductor radiation emitter package of claim 90, wherein at least two of said electrical leads are retained by said encapsulant.

102. The semiconductor radiation emitter package of claim 90, wherein said encapsulant covers a portion of said heat extraction member equal to or less than 65% of the total surface area of said heat extraction member.

103. The semiconductor radiation emitter package of claim 90, wherein the bulk of said electrical leads and said heat extraction member are composed substantially of the same material.

104. The semiconductor radiation emitter package of claim 90, wherein said at least one semiconductor radiation emitter includes two semiconductor radiation emitters that emit illumination having binary complementary hues that may mix to form white light.

105. The semiconductor radiation emitter package of claim 90, wherein said at least one semiconductor radiation emitter includes three semiconductor radiation emitters that emit illumination having ternary complementary hues that may mix to form white light.

106. The semiconductor radiation emitter package of claim 90, wherein the semiconductor radiation emitter package has a power capacity of at least about 150 mW.

107. The semiconductor radiation emitter package of claim 90, and further comprising at least one recessed optically reflective cup formed in the heat extraction member, said at least one semiconductor radiation emitter being mounted within said at least one recessed optically reflective cup, wherein the depth of said at least one recessed optically reflective cup is equal to or greater than the height of said at least one semiconductor radiation emitter, each measured in the dimension parallel to the optical axis of the reflective cup within which said at least one semiconductor radiation emitter is mounted.

108. The semiconductor radiation emitter package of claim 90, wherein said encapsulant comprises two different materials.

109. The semiconductor radiation emitter package of claim 108, wherein one of said two different materials is a transparent epoxy.

110. The semiconductor radiation emitter package of claim 108, wherein one of said two different materials is a stress relieving gel.

111. The semiconductor radiation emitter package of claim 110, wherein the stress relieving gel is silicone.

112. The semiconductor radiation emitter package of claim 110, wherein the stress relieving gel is applied over said at least one semiconductor radiation emitter.

113. The semiconductor radiation emitter package of claim 112, wherein one of said two different materials is a hard molding compound that is formed over the stress relieving gel.

114. The semiconductor radiation emitter package of claim 113, wherein said hard molding compound is epoxy.

115. The semiconductor radiation emitter package of claim 108, wherein said two different materials include a first hard molding compound and a second hard molding compound.

116. The semiconductor radiation emitter package of claim 115, wherein said first hard molding compound is substantially transparent to radiation emitted by said at least one semiconductor radiation emitter.

117. The semiconductor radiation emitter package of claim 116, wherein said first hard molding compound is provided within an optical path of said at least one semiconductor radiation emitter and is shaped to define a lens.

118. The semiconductor radiation emitter package of claim 117, wherein said second hard molding compound is provided in regions not within the optical path of said at least one semiconductor radiation emitter.

119. The semiconductor radiation emitter package of claim 118, wherein said second hard molding component is substantially opaque.

120. The semiconductor radiation emitter package of claim 115, wherein said second hard molding compound is provided where said encapsulant retains said electrical leads.

121. The semiconductor radiation emitter package of claim 90, wherein said encapsulant is molded directly onto a portion of said heat extraction element.

122. The semiconductor radiation emitter package of claim 90, wherein said second hard molding compound is molded directly onto a portion of said heat extraction element.

123. A semiconductor radiation emitter package comprising:

a heat extraction element;

at least two electrical leads having a greater thermal resistance than said heat extraction element;

at least one semiconductor radiation emitter mounted on a first surface of said heat extraction element, wherein when said at least one semiconductor emitter is activated, the semiconductor radiation emitter package emits white light;

a first hard molding compound substantially transparent to radiation emitted by said at least one semiconductor radiation emitter, said first hard molding compound is provided within the optical path of radiation emitted from said at least one semiconductor radiation emitter; and

a second hard molding compound covering a portion of said heat extraction element, while leaving exposed a portion of said heat extraction element, said second hard molding compound being different from said first hard molding compound and encapsulating a portion of said electrical leads so as to retain said electrical leads.

124. The semiconductor radiation emitter package of claim 123, wherein said heat extraction element having a thickness in a direction that is substantially parallel to the direction in which radiation is emitted from the semiconductor radiation emitter package that is greater than the thickness of said electrical leads.

125. The semiconductor radiation emitter package of claim 123, wherein said second hard molding compound is substantially opaque.

126. The semiconductor radiation emitter package of claim 123, wherein said heat extraction element includes a first surface on which said at least one semiconductor radiation emitter is mounted, said second hard molding compound covers a portion of the first surface of said heat extraction element, while leaving exposed at least a portion of a second surface of said heat extraction element that is opposite the first surface, the exposed portion of the second surface being directly opposite an area of the first surface where said at least one semiconductor radiation emitter is mounted.

127. The semiconductor radiation emitter package of claim 123, wherein the heat extraction member comprises a depression containing the at least one semiconductor radiation emitter.

128. The semiconductor radiation emitter package of claim 127, wherein the depression is coated with an optically reflective coating.

129. The semiconductor radiation emitter package of claim 123, wherein a portion of the first hard molding compound is formed as a lens.

130. The semiconductor radiation emitter package of claim 123, wherein the semiconductor radiation emitter comprises a conductive base in electrical contact with the heat extraction member.

131. The semiconductor radiation emitter package of claim 123, wherein the at least one semiconductor radiation emitter comprises a light emitting diode.

132. The semiconductor radiation emitter package of claim 123 and further comprising a fluorescent material.

133. The semiconductor radiation emitter package of claim 132, wherein said fluorescent material is dispersed in said encapsulant.

134. The semiconductor radiation emitter package of claim 133, wherein said fluorescent material is one or more of a fluorescent dye, pigment and phosphor.

135. The semiconductor radiation emitter package of claim 123, wherein:

said second hard molding compound forms a plurality of sides;

each of said electrical leads extends through one of a first set of the sides; and

said heat extraction member extends through at least one of a second set of the sides, the second set of the sides different from the first set of the sides.

136. The semiconductor radiation emitter package of claim 123, wherein the bulk of said electrical leads and said heat extraction member are composed substantially of the same material.

137. The semiconductor radiation emitter package of claim 123, wherein said at least one semiconductor radiation emitter includes two semiconductor radiation emitters that emit illumination having binary complementary hues that may mix to form white light.

138. The semiconductor radiation emitter package of claim 123, wherein said at least one semiconductor radiation emitter includes three semiconductor radiation emitters that emit illumination having ternary complementary hues that may mix to form white light.

139. The semiconductor radiation emitter package of claim 123, wherein the semiconductor radiation emitter package has a power capacity of at least about 150 mW.

140. The semiconductor radiation emitter package of claim 123, and further comprising at least one recessed optically reflective cup formed in the heat extraction member, said at least one semiconductor radiation emitter being mounted within said at least one recessed optically reflective cup, wherein the depth of said at least one recessed optically reflective cup is equal to or greater than the height of said at least one semiconductor radiation emitter, each measured in the dimension parallel to the optical axis of the reflective cup within which said at least one semiconductor radiation emitter is mounted.

141. The semiconductor radiation emitter package of claim 123, wherein said second hard molding compound is molded directly onto a portion of said heat extraction element.

142. The semiconductor radiation emitter package of claim 123, wherein said encapsulant defines a plurality of sides and said heat extraction element extends out through two of said sides.

143. The semiconductor radiation emitter package of claim 123, wherein said second hard molding compound defines a plurality of sides and said heat extraction element extends out through two of said sides.

144. The semiconductor radiation emitter package of claim 123, wherein said first hard molding compound is made of a single transparent material.

145. An LED package comprising:

a heat extraction element having a first surface and a second surface that is opposite the first surface;

a first electrical lead and a second electrical lead, said electrical leads having a greater thermal resistance than said heat extraction element;

an LED chip mounted to the first surface of said heat extraction element for emitting light generally along an optical path, wherein said LED chip is energized via said first and second electrical leads, when said LED chip is energized, the LED package is capable of emitting white light; and

an encapsulant covering a portion of said first and second electrical leads, said LED chip, and a portion of said heat extraction element, said encapsulant is formed to leave exposed at least a portion of the second surface of said heat extraction member, the exposed portion of said heat extraction member including a region generally directly opposite a location on the first surface where said LED chip is mounted,

wherein said encapsulant comprises two different materials including a first hard molding compound and a second hard molding compound, said first hard molding compound is substantially transparent to light emitted by said LED chip and is provided within the optical path of light emitted from said LED chip and is shaped to define a lens, wherein said second hard molding compound is provided where said encapsulant covers said electrical leads and in regions generally not within the optical path of light emitted from said LED chip, said second hard molding compound is substantially opaque,

wherein a cross-sectional area of said heat extraction element measured in a plane normal to the path between said LED chip and the nearest exposed surface of said heat extraction element is greater than a cross-sectional area of each of said electrical leads measured in a plane that is normal to the path of heat flow between said LED chip and the nearest exposed surface of said electrical leads, during operation of the package,

wherein said encapsulant forms a plurality of sides, said first and second electrical leads extend through one of a first set of encapsulant sides, said heat extraction member extends through at least one of a second set of encapsulant sides including at least two sides, the second set of encapsulant sides different from the first set of encapsulant sides, and

wherein said heat extraction element having a thickness in a direction that is substantially parallel to the direction in which light is emitted from the LED package that is greater than the thickness of said electrical leads.

146. The LED package of claim 145, wherein said first hard molding compound is a transparent epoxy.

147. The LED package of claim 145, wherein said encapsulant further comprises a stress relieving gel.

148. The LED package of claim 147, wherein the stress relieving gel is silicone.

149. The LED package of claim 147, wherein the stress relieving gel is applied over said LED chip.

150. The LED package of claim 145, wherein said first surface of said heat extraction element is a bottom surface that lies in a plane below a bottommost surface of said electrical leads and wherein said second hard molding compound does not extend below the plane of the bottom surface of said heat extraction element.

151. The LED package of claim 145, wherein said second set of sides of said encapsulant includes adjacent sides, and wherein said first set of sides of said encapsulant includes a single side of said encapsulant.

152. The LED package of claim 145 and further comprising an additional LED chip, wherein said LED chip and said additional LED chip emit illumination having binary complementary hues that may mix to form white light.

153. The LED package of claim 145 and further comprising a fluorescent material.

154. The LED package of claim 153, wherein said fluorescent material is one or more of a fluorescent dye, pigment and phosphor.

155. The LED package of claim 145, wherein the LED package has a power capacity of at least about 150 mW.

156. The LED package of claim 145, wherein said second hard molding compound is molded directly onto a portion of said heat extraction element.