Method of forming a semiconductor package and structure thereof

• US 7,030,469 B2
• Filed: 09/25/2003
• Issued: 04/18/2006
• Est. Priority Date: 09/25/2003
• Status: Expired due to Term

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Mahadevan, Dave S., Salian, Arvind S., Chapman, Michael E.
• Primary Examiner(s): Zarneke, David A.
• Application Number:
  US10/670,631
• Publication Number:
  US 20050067676A1
• Time in Patent Office: 936 Days
• Field of Search: None
• US Class Current: 257/659
• CPC Class Codes: H01L 21/561 Batch processing
• 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 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 2224/85 using 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 2225/06562 at least one device in the stack being rotated or offset
• CPC Class Codes: H01L 23/3107 the device being completely enclosed
• CPC Class Codes: H01L 23/4952 the additional leads being a bump or a wire
• CPC Class Codes: H01L 23/49575 Assemblies of semiconductor devices on lead frames
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• 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 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01006 : 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 2924/01023 : Vanadium [V]
• 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 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• 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 2924/1433 : Application-specific integrated circuit [ASIC]
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/1815 : Shape
• CPC Class Codes: H01L 2924/19043 : being a resistor
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding

Abstract

An electromagnetic interference (EMI) and/or electromagnetic radiation shield is formed by forming a conductive layer (42, 64) over a mold encapsulant (35, 62). The conductive layer (42, 64) may be electrically coupled using a wire to the leadframe (10, 52) of the semiconductor package (2, 50). The electrical coupling can be performed by wire bonding two device portions (2, 4, 6, 8) of a leadframe (10) together and then cutting the wire bond (32) by forming a groove (40) in the overlying mold encapsulant (35) to form two wires (33). The conductive layer (42) is then electrically coupled to each of the two wires (33). In another embodiment, a looped wire bond (61) is formed on top of a semiconductor die (57). After mold encapsulation, portions of the mold encapsulant (62) are removed to expose portions of the looped wire bond (61). The conductive layer (64) is then formed over the mold encapsulant (62) and the exposed portion of the looped wire bond (61) so that the conductive layer (64) is electrically coupled to the looped wire bond (61).

Claims

1. A semiconductor package comprising:

a leadframe having a flag and a bond pad;

a semiconductor die attached to the flag and electrically coupled to the bond pad;

a mold encapsulant over the semiconductor die;

a conductive layer over the mold encapsulant, wherein the conductive layer comprises a ferromagnetic material; and

a wire electrically coupling the leadframe to the conductive layer.

2. The semiconductor package of claim 1, wherein the conductive layer comprises NiFe.

3. The semiconductor package of claim 1, wherein the conductive layer comprises an element selected from the group consisting of aluminum, copper, tin and zinc.

4. The semiconductor package of claim 1, wherein the conductive layer comprises a ferromagnetic material and a nonferromagnetic metal.

5. The semiconductor package of claim 1, wherein the wire is coupled to the semiconductor die.

6. The semiconductor package of claim 1, wherein the wire is coupled to the leadframe through a pad.

7. The semiconductor package of claim 1, wherein the conductive layer is an electromagnetic shield.

8. A method of forming a semiconductor package, the method comprising:

providing a leadframe having a flag;

attaching a semiconductor die to the flag;

forming a mold encapsulant over the semiconductor die;

forming a conductive layer over the mold encapsulant, wherein forming a conductive layer further comprises electrically coupling the conductive layer to the wire; and

electrically coupling the leadframe to the conductive layer using a wire, wherein electrically coupling the leadframe to the conductive layer using a wire further comprises;

providing a wire having a first end and a second end;

electrically coupling the first end and the second end of the wire to the semiconductor die; and

removing a portion of the mold encapsulant to expose a portion of the wire.

9. The method of claim 8, wherein:

forming a mold encapsulant over the semiconductor die, further comprises forming the mold encapsulant over the wire.

10. The method of claim 9, wherein removing the mold encapsulant to expose the wire further comprises forming a groove in the mold encapsulant, wherein the groove has sidewalls.

11. The method of claim 10, wherein forming the conductive layer further comprises forming the conductive layer over the sidewalls of the groove.