Triple-damascene interposer

#The present invention relates generally to interconnectors for microelectronic circuits. In particular, this invention is an interface that integrates two or more integrated circuits into a stacked three-dimensional structure.

#An interposer is a device that is used as an interface to provide interconnections between two or more integrated circuits to produce a stacked three-dimensional structure. Individual IC's, printed circuit boards and hybrid substrates, each being an electronic subsystem, may be connected using an interposer to form a more complex system.

#The particular features and advantages of the devices and methods described here will become apparent when taking the following description in conjunction with one or more of the accompanying FIGS. 1-3 of the drawings:

#FIG. 1 is a cross-sectional view of an interposer as described here;

#FIG. 2 illustrates the interposer in use to provide connections between a memory device and a logic device; and

#The following Reference Numbers may be used in conjunction with one or more of the accompanying FIGS. 1-3 of the drawings: 100 Interposer device 110 Substrate of silicon, quartz or semiconductor 120 DTSV, Dual-damascene Through-Silicon Via 130 Via Fill 140 Damascene top trench 150 Damascene T1 top interconnect 160 Top ILD 170 TV1 Top Via 180 TM1 Top interconnect 190 Dual-damascene bottom trench 200 Dual-damascene B1 bottom interconnect 210 Bottom ILD 220 BV1 Bottom Via 230 BM1 Bottom interconnect 250 Pad Passivation layer 260 Connective bond 280 Logic Function Integrated Circuit 290 Memory Function Integrated Circuit

#An interposer is an interface chip that is used to make electrical connections for integration of two or more integrated circuits into a stacked three-dimensional structure where each individual chip is connected to form an electronic system. In addition to traditional integrated circuitry, the presently described interposer accommodates connectivity between less traditional subsystems such as MEMS (Micro-Electro-Mechanical Systems) as well as less exotic technologies in the form of PC boards and hybrid substrates.

#The presently described interposer takes advantage of damascene processing. Though well-known by those skilled in the art, a brief review is offered here. Damascene processing involves the unpatterned deposition of a dielectric material which is then patterned and etched to produce holes and/or trenches. The surface is then filled, generally with copper, after which the damascene (copper) layer is removed, generally by CMP, to leave a smooth surface. Optionally, a thin barrier film may be applied prior to the copper to prevent diffusion of copper into the dielectric. In a single damascene process, copper is deposited into the holes or trenches, with the result being that when filled the holes become conductive vias, and metal-filled trenches become wire lines for routing of interconnections. For dual-damascene processing both holes and trenches are fabricated, to different depths, before the deposition of copper. This results in the simultaneous formation of both conductive vias and wire lines for interconnection routing, which reduces the number of processing steps.