Tape bonding material and structure for electronic circuit fabrication
AssigneeOlin Corporation
InventorSheldon H. Butt
Life of this patent
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Abstract
An electronic circuit assembly is disclosed including a semiconductor die having an aluminum therminal pad on its top surface. A lead frame is disposed adjacent the semiconductor die and is adapted to be electrically connected to the die. An electrical connection device interconnects the terminal pad to the lead frame. The electrical connection device includes a biclad transport tape comprising a first member formed from a nickel containing material and a second member formed from a copper containing material. The transport tape is disposed in the electronic circuit assembly with its first member bonded to the terminal pad and its second member bonded to the lead frame. The transport tape may be constructed so as to efficiently dissipate heat from the semiconductor die.
Claims17
A transport tape adapted for electrically interconnecting at least one terminal pad on a semiconductor die to at least one of a plurality of leads;
- said transport tape comprising:
- a plurality of interconnect tape fingers, at least tape fingers adapted to be bonded at a first end to said terminal pad and further adapted to be bonded at a second end to one of said plurality of leads;
- said transport tape further comprising:
- a first layer of about 20 to about 40% nickel and the remainder copper, and having a yield strength of at least about 60,000 psi, said first layer for reducing the formation of intermetallics and being adapted for bonding to said terminal pad;
- a second layer formed from a copper containing material having a yield strength less than about 40,000 psi, said second layer being a softer material than said first layer and adapted to be bonded to one of said plurality of leads;
- a third layer formed of a copper alloy having a yield strength of at least 60,000 psi and a conductivity of at least about 50% IACS;
- said second and third layers being in direct contact with opposing sides of said first layer and bonded thereto.
A transport tape adapted for electrically interconnecting at least first and second terminal pads on a semiconductor die to at least one of a plurality of leads,
- said transport tape comprising:
- a plurality of interconnected tape fingers, at least one of said tape fingers having a first end section adapted to be bonded at either end of said end section to said first and second terminal pads, said first end section being shaped into an arch between the ends of said end section, said arch adapted to minimize the tendency of the tape to sag and contact said die, said at least one of said tape fingers further having a second end section adapted to be bonded to one of said plurality of leads,
- said transport tape further comprising:
- a first layer formed of a copper containing material having a yield strength of at least about 60,000 psi and a conductivity of at least about 50% IACS, and
- a second layer formed from a nickel containing material, said second layer being in direct contact with and bonded to said first layer and further adapted for connection to said first and second terminal pads on said semiconductor die.
A sag resistant tape having a plurality of metal fingers each adapted for electrically interconnecting at least one terminal pad on a semiconductor die to one of a plurality of external leads;
- said tape comprising:
- a clad material formed of a softer metal or alloy layer, a first high strength alloy layer and a second high strength alloy layer, said softer layer and said second high strength alloy layer, bonded onto opposing sides of said first high strength alloy layer;
- said first high strength layer comprising a copper alloy having a yield strength of at least about 60,000 psi for resisting sag in the tape;
- said second high strength layer having a yield strength of at least about 60,000 psi and a conductivity of at least about 50% IACS;
- and
- said softer layer being a metal or alloy having a yield strength substantially less than said high strength layers.
A sag resistant tape having a plurality of metal fingers each adapted for electrically interconnecting at least one terminal pad on a semiconductor die to a plurality of external leads, said tape comprising:
- a clad material formed of a high strength alloy layer and a softer metal or alloy layer;
- said high strength layer comprising a copper alloy having a yield strength of at least about 60,000 psi for resisting sag in the tape, said high strength layer having a conductivity of at least about 50% IACS;
- and
- said softer layer being a metal or alloy having a yield strength substantially less than said high strength layer, said softer layer having a yield strength of less than about 40,000 psi.
Dependencies are inferred from the claim text.