Motorola Corporation

William M Beckenbaugh

Cynthia M Melton

Dennis Brian Miller

Kevin Douglas Moore

John W Stafford

Ken Cholewczynski

William H Lytle

George Thomas Valliath

Andrew Frederick Skipor

Kevin W Jelley

Steven Michael Scheifers

Carl J Raleigh

Kent W Hansen

Daniel Joseph Viza

Conrad S Monroe

Bernard Berman

A microelectronic assembly (10) is formed by bonding an integrated circuit component (20) to a substrate (12). The substrate (12) includes a via (22) and a metal contact (24) closing the via (22). A bonding agent (14), such as a solder paste or a conductive epoxy, is dispensed into the via (22) adjacent the metal contact (24). A carrier tape (16) that includes partially-cured films (18) is placed onto the substrate (12) such that the film (18) covers the via (22) and forms a gap (28) between the substrate (12) and the film (18). The integrated circuit component (20) is superposed onto the substrate (12) such that conductive bumps (26) on the integrated circuit component (20) perforate and extend through the film (18) and contact the bonding agent (14) in the via (22). Portions (44) displaced during perforation are received in the gap (28). The film (18) is thus interposed between the substrate (12) and the integrated circuit component (20). The preassembly (38) is then heated to bond the bonding agent (14) to the metal contact (24) and to cure the film (18) to form an integral assembly (10).

Method for forming a microelectronic assembly

A method of forming contact pads (140) that allows for wafer level testing and burn-in of semiconductor die (22). A plurality of semiconductor die (22) are formed upon a semiconductor wafer (20), each semiconductor die (22) having a plurality of bonding pads (78). A contact pad (140) is formed overlying each bonding pad (78) and is electrically coupled to the bonding pad (78) and to wafer test pads (38) through vertical and/or horizontal wafer conductors (42-47 and 52-53 respectively) so that each semiconductor die (22) is uniquely identified. Contact pads (140) protect underlying bonding pads (78) during the formation and removal of vertical and/or horizontal wafer conductors (42-47 and 52-53 respectively). Thus, wafer level electrical testing and/or burn-in can be performed prior to designating a final packaging method for the semiconductor die (22).

Method of forming contact pads for wafer level testing and burn-in of

A solder paste of the type utilized in forming a solder onnectin for a microelectronic package comprises a mixture of compositionally distinct metal powders. The paste comprises a first metal powder formed of tin-bismuth solder alloy. The paste further comprises a second metal powder containing gold or silver. During reflow, the gold or silver alloys with the tin-bismuth solder to increase the melting part and enhance mechanical properties of the product connection.

Tin bismuth solder paste, and method using paste to form connection

A liquid crystal display device, (10 in FIG. 1) comprises a liquid crystal panel (12) and a backside illuminator (14). The liquid crystal includes pixels (36) separated by a matrix area (37). The backside illuminator comprises a waveguide (40) having a face (44) facing the backside (18) of the liquid crystal panel and including light-emitting sites (48) disposed in registration with the pixels and separated by non-emitting surface (46). During operation, light received from a suitable source (52, 54, 56) is transmitted within the waveguide to the sites and emitted to illuminate the corresponding pixels.

Liquid crystal display device with pixel registration illumination

A low temperature-wetting solder paste for forming a tin-base solder connection comprises a mixture of compositionally distinct first and second solder powders. The first solder is formed predominantly of tin, preferably at least 90 weight percent. The second powder is formed of a tin alloy containing indium or bismuth and having a melting temperature less than the first powder. During soldering, the second powder melts during the early stages of the heating cycle to initiate wetting of the faying surfaces and promote dissolution of the first powder, thereby reducing the time and temperature required to form the solder connection.

Low temperature-wetting tin-base solder paste

A method for forming a solder-bumped terminal on a planar dielectric substrate utilizes a terminal of a particular configuration and comprises depositing onto the terminal a thin plate of solder alloy and reflowing the solder alloy to form a bump. The terminal configuration includes an enlarged terminal pad connected to a relatively narrow linear runner section. Preferably, the runner section width is between about 50 and 150 microns, whereas the pad width is between about 1.2 and 2.0 times the runner section width. The terminal is initially fabricated to include a metal layer adjacent the substrate formed, for example, of copper and a thin, outer plate composed of the solder alloy. The solder plate is deposited in a uniform thickness to both the terminal pad and the adjacent runner section. The terminal is then heated to melt the solder plate, whereupon the molten solder is drawn from the runner onto the enlarged pad to form a bump. In a preferred embodiment, a solder plate between about 10 and 25 microns is electrodeposited onto the terminal and reflowed to form a bump having a height between 60 and 80 microns.

Solder plate reflow method for forming solder-bumped terminals

A method for forming a solder-bumped circuit trace on a planar dielectric substrate includes fabricating a trace having an intersection between linear section, depositing onto the trace a uniform thin plate of solder alloy and reflowing the solder alloy to form a bump at the intersection. More particularly, the trace comprises first and second linear sections that intersect at an angle between 45 degrees and 135 degrees and have widths preferably between 50 and 150 microns. The solder plate is deposited, preferably by electroplating, at a thickness between about 10 and 25 microns. Thereafter, when the trace is heated to melt the solder layer, the solder coalesces at the intersection to form the bump.

Solder plate reflow method for forming a solder bump on a circuit trace

A body formed of a lead-tin solder alloy is pretreated to deposit palladium thereon prior to soldering to a metallic substrate. It is found that the palladium deposit enhances wetting of the substrate by the solder liquid during reflow and thereby, upon cooling, produces a strong metallurgical bond. In a preferred embodiment, lead-tin solder balls are pretreated by applying tin-palladium colloidal particles and dissociating the particles to form a discontinuous metallic palladium deposit.

Growing community of inventors

Barrington, IL, United States of America

William M Beckenbaugh