Multiple row fine pitch leadless leadframe package with use of half-etch process
AssigneeNational Semiconductor Corporation
InventorsJaime Bayan, Peter Howard Spalding
Life of this patent
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Abstract
A leadless leadframe panel comprising a partially etched top surface of a substrate panel that forms recessed regions that define a portion of a first and a second set of tie bars and a portion of a first and second set of contact pads. A bottom surface of the panel forms lower recessed regions that define the remaining portion of the first and second set of tie bars and the remaining portion of the first and second set of contact pads. The resulting contact pads are connected to a respective one of the tie bars.
Claims21
A leadless leadframe panel that has a bottom surface and an opposing top surface, a distance between the bottom surface and the top surface being a thickness of said panel, said panel also having multiple rows of contact pads, comprising:
- a first set of tie bars;
- a first set of contact pads, wherein each contact pad of said first set is connected to a respective one of the tie bars of said first set of tie bars, said contact pads of said first set having a contact surface that is coplanar with the bottom surface of said panel, a first maximum thickness of each of said first set of contact pads being equal to the thickness of said panel, wherein the first maximum thickness is attained where each tie bar of the first set of tie bars is connected to each contact pad of the first set of contact pads;
- a second set of tie bars, the tie bars of said first and second set being in parallel formation and the tie bars of said first and second set being formed in an alternating formation, each of said second set of tie bars has a thickness that is less than the thickness of said panel, said first and second set of tie bars being aligned with the top surface of said panel;
- and
- a second set of contact pads, wherein each contact pad of said second set is connected to a respective one of the tie bars of said second set of tie bars, the contact surfaces of said second set of contact pads being in the same plane as the bottom surface of said panel, and a second maximum thickness of each of said second set of contact pads being equal to the thickness of said panel, wherein the second maximum thickness is attained where each tie bar of the second set of tie bars is connected to each contact pad of the second set of contact pads.
A leadframe panel for manufacturing packaged semiconductor devices comprising:
- at least one row of elongated tie bars that are spaced closely next to each other wherein each of the tie bars have a length, width, and a thickness, wherein at least a lengthwise portion of each of the tie bars are parallel to each other, and wherein every other tie bar is a thin tie bar and the tie bars between each thin tie bar are thick tie bars, at least a portion of each thin tie bar having a thickness that is less than the thickness of the thick tie bars.
Dependencies are inferred from the claim text.