Magnetoresistive device and method of packaging same
View Patent ↗A magnetoresistive memory device 20 includes dies 24 and 38, each of which contains magnetically sensitive material 50. A method 64 of packaging the magnetoresistive memory device 20 entails coupling the die 24 to a substrate 22, forming interconnections 52 between bonding pads 32 on the die 24 to connection sites 54 spaced apart from the die 24. A magnetic shield 36 is bonded to a top surface 30 of the die 24 following formation of the interconnections 52. The die 38 is attached to the magnetic shield 36, interconnections 56 are formed between bonding pads 44 on the die 38 to connection sites 58 spaced apart from the die 38, and a magnetic shield 48 is adhered to the die 38 following formation of the interconnections 56.
1. A magnetoresistive memory device comprising:
a substrate;
a first die coupled to said substrate, said first die containing magnetoresistive memory cells and having a first top surface with first bonding pads positioned thereon, said first bonding pads being interconnected with associated first connection sites spaced apart from said first die;
a first adhesive applied to said first top surface, excluding application of said first adhesive on said first bonding pads when said first adhesive is applied to said first top surface;
a first magnetic shield bonded to a first top surface of said first die via said first adhesive;
a second die attached to said first magnetic shield, said second die containing said magnetoresistive memory cells and having a second top surface with second bonding pads positioned thereon, said second bonding pads being interconnected with associated second connection sites spaced apart from said first die;
a second adhesive applied to said second top surface, excluding application of said second adhesive on said second bonding pads when said second adhesive is applied to said second top surface; and
a second magnetic shield adhered to said second top surface using said second adhesive.
2. A magnetoresistive memory device as claimed in claim 1 wherein each of said first and second adhesives are a non-conductive adhesive paste.
3. A magnetoresistive memory device as claimed in claim 1 wherein each of said first and second magnetic shields is formed from a metal material provided in a sheet format.
4. A magnetoresistive memory device as claimed in claim 1 further comprising:
a first stress buffer material interposed between said first top surface of said first die and said first magnetic shield; and
a second stress buffer material interposed between said second top surface of said second die and said second magnetic shield.
5. A magnetoresistive memory device as claimed in claim 1 further comprising:
a third magnetic shield adhered to a bottom surface of said first die.
6. A magnetoresistive memory device as claimed in claim 1 wherein the substrate comprises:
a leadframe formed from a magnetic permeable material.