Lead structure and method of manufacture
AssigneeTessera, Inc.
InventorsJohn W. Smith, Christopher M. Pickett
Life of this patent
Estimating the term…
Abstract
A microelectronic assembly is made by bonding the tip ends of leads on a first element to bonding contacts on a second element. The tip ends of the leads are releasably connected to the first element, so that the leads are held in place during the bonding process. After bonding, the first and second elements are heated or cooled to cause differential thermal expansion, which breaks at least some of the releasable attachments of the tip ends, leaving the leads free to flex.
Claims38
A method of making a microelectronic assembly comprising:
- (a) providing a first element having a first surface and a plurality of leads extending over said first surface, said leads having anchor ends attached to said first element and tip ends remote from said anchor ends, the tip ends being releasably attached to said first element;
- (b) connecting said tip ends of said leads to an a second element, said releasable attachment maintaining said tip ends in position relative to said first element at least until commencement of said connecting step;
- and then
- (c) causing differential expansion or contraction of said elements so as to move said tip ends relative to said first element and break at least some of said releasable attachments.
A method of making a microelectronic assembly comprising:
- (a) providing first and second elements having opposing surfaces extending in horizontal directions and leads connected between said opposing surfaces, and leads extending between said opposing surfaces;
- (b) causing at least one of said elements to warp so as to deform at least a part of at least one of said opposing surfaces in a vertical direction away from the other one of said opposing surfaces and thereby deform at least some of said leads towards a vertically-extensive disposition.
An element for use in a semiconductor assembly, said element having a body defining a first surface and a plurality of leads, said leads having anchor ends attached to said body and having tip ends releasably attached to said body or movable with respect to said body, the element further comprising restraining straps, each said restraining strap having a first end permanently connected to said body and a second end adapted to be connected to a second element, each of said restraining straps having a direction vector from its first end to its second end, different ones of said restraining straps having direction vectors pointing in different directions.
An element for use in manufacturing microelectronic assemblies comprising a carrier defining a surface extending in horizontal directions, said structural element including a plurality of layers having different coefficients of thermal expansion, and one or more microelectronic elements secured to said surface, said one or more microelectronic elements having leads thereon, said leads on said one or more microelectronic elements extending generally horizontally, said leads having anchor ends attached to said microelectronic elements and tip ends displaceable in a vertical direction away from said surface.
Dependencies are inferred from the claim text.