Abstract: Semiconductor assemblies, structures, and methods of fabrication are disclosed. A coating is formed on an electrically conductive pillar. The coating, which may be formed from at least one of a silane material and an organic solderability protectant material, may bond to a conductive material of the electrically conductive pillar and, optionally, to other metallic materials of the electrically conductive pillar. The coating may also bond to substrate passivation material, if present, or to otherwise-exposed surfaces of a substrate and a bond pad. The coating may be selectively formed on the conductive material. Material may not be removed from the coating after formation thereof and before reflow of the solder for die attach. The coating may isolate at least the conductive material from solder, inhibiting solder wicking or slumping along the conductive material and may enhance adhesion between the resulting bonded conductive element and an underfill material.

Abstract: A WSP die having a redistribution layer (“RDL”) with an RDL capture pad that has an RDL pad central axis RR and a RDL pad outer peripheral edge arranged about the RDL capture pad central axis RR and an under bump metal (UBM) pad positioned above the RDL capture pad. The UBM pad has a UBM pad central axis UU and a UBM pad outer peripheral edge arranged around the UBM pad central axis UU. The UBM pad central axis UU is laterally offset from the RDL pad central axis RR.

Abstract: In an electronic component mounting structure, a semiconductor element (an electronic component) provided with an electrode pad and a board provide with an electrode pad corresponding to the electrode pad are connected via a conductive material portion. On a surface of the board, there is formed solder resist having an opening regulating an area of the electrode pad. The conductive material portion is formed to protrude from a surface of the solder resist. An elastic coefficient of the conductive material portion is lower than that of the solder resist. A solder bump and the conductive material portion are connected via a metal layer. The conductive material portion is formed to have an area larger than that of the opening of the solder resist. An edge of the conductive material portion is adhered to a portion of the surface of the solder resist. Thus, in a case of mounting an electronic component on a board by flip-chip connection, a reliability of connection can be secured.

Abstract: One illustrative method disclosed herein includes forming a conductive pad in a layer of insulating material, forming a passivation layer above the conductive pad, performing at least one etching process on the passivation layer to define an opening in the passivation layer that exposes at least a portion of the conductive pad, forming a protective layer on the passivation layer, in the opening and on the exposed portion of the conductive pad, forming a heat-curable material layer above the protective layer, performing an etching process to define a patterned heat-curable material layer having an opening that exposes a portion of the protective layer, performing an etching process on the protective layer to thereby expose at least a portion of the conductive pad and forming a conductive bump that is conductively coupled to the conductive pad.

Abstract: Underfill flow guide structures and methods of using the same are provided with a module. In particular the underfill flow guide structures are integrated with a substrate and are configured to prevent air entrapment from occurring during capillary underfill processes.

Abstract: A method of forming an electronic device provides an electronic device substrate having a solder bump pad located thereover. A nickel-containing layer is located over the solder bump pad. A copper-containing layer is formed on the nickel-containing layer prior to subjecting the electronic device to a reflow process.

Abstract: A stack of a first and second semiconductor structures is formed. Each semiconductor structure includes: a semiconductor bulk, an overlying insulating layer with metal interconnection levels, and a first surface including a conductive area. The first surfaces of semiconductor structures face each other. A first interconnection pillar extends from the first surface of the first semiconductor structure. A housing opens into the first surface of the second semiconductor structure. The housing is configured to receive the first interconnection pillar. A second interconnection pillar protrudes from a second surface of the second semiconductor structure which is opposite the first surface. The second interconnection pillar is in electric contact with the first interconnection pillar.

Abstract: A conductive structure for a semiconductor chip and a method for forming the conductive structure are provided. The semiconductor chip comprises a plurality of first pads and second pads. The pad area is defined with a first area, a second area and a third area, wherein the first area is located between the second area and the third area. Each of the first pads and the second pads are interlaced to each other on the first area. The conductive structure comprises a plurality of conductive bumps formed on each of the first pads and the second pads respectively to electrically connect with each of the first pads and the second pads. Each of the conductive bumps has a first bump-width disposed on the first area and a second bump-width disposed on one of the second and third areas in which the first bump-width is shorter than the second bump-width.

Abstract: Electronic device packages and related methods are provided. The electronic device package includes a first substrate having a first contact portion disposed thereon, a bump having a first contact surface connected to the first contact portion and a second contact surface disposed opposite to the first contact surface, and a buffer spring pad portion between the first contact portion of the first substrate and the first contact surface of the bump. The buffer spring pad portion includes at least two different conductive material layers which are stacked.

Abstract: A bump structure includes a first bump and a second bump. The first bump is disposed on a connection pad of a substrate. The first bump includes a lower portion having a first width, a middle portion having a second width smaller than the first width, and an upper portion having a third width greater than the second width. The second bump is disposed on the upper portion of the first bump.

Abstract: A semiconductor wafer has a first conductive layer formed over its active surface. A first insulating layer is formed over the substrate and first conductive layer. A second conductive layer is formed over the first conductive layer and first insulating layer. A UBM layer is formed around a bump formation area over the second conductive layer. The UBM layer can be two stacked metal layers or three stacked metal layers. The second conductive layer is exposed in the bump formation area. A second insulating layer is formed over the UBM layer and second conductive layer. A portion of the second insulating layer is removed over the bump formation area and a portion of the UBM layer. A bump is formed over the second conductive layer in the bump formation area. The bump contacts the UBM layer to seal a contact interface between the bump and second conductive layer.

Abstract: The invention includes embodiments of a method for designing a flip chip and the resulting structure. The starting point is a flip chip with a semiconductor substrate, one or more wiring levels, and a plurality of I/O contact pads (last metal pads/bond pads) for receiving and sending electrical current. There is also a plurality of C4 bumps for connecting the I/O contact pads to another substrate. Then it is determined which of the C4s of the plurality of C4 bumps have a level of susceptibility to electromigration damage that meets or exceeds a threshold level of susceptibility, and in response, plating a conductive structure with a high electrical current carrying capacity (such as a copper pillar, copper pedestal, or partial copper pedestal) onto the corresponding I/O contact pads and adding a solder ball to a top portion of the conductive structure. The resulting structure is a flip chip wherein only a select few C4 bumps use enhanced C4s (such as copper pedestals) reducing the chance of defects.

Abstract: A driving circuit for a liquid crystal display, the driving circuit being an integrated circuit having electrode pads disposed on a surface of the integrated circuit, bumps formed on the electrode pads, a conductive adhesive layer formed on the bumps and conductive particles having an outer conductive layer and an elastic polymer inner portion deposited on the conductive adhesive layer. The driving circuit is mounted on a TFT array substrate and bonded to pads provided on the substrate. The conductive particles reduce electrical connection resistance that would otherwise arise due to height differences between bumps in a plurality of bumps, and prevents electrical open defects and an electrical short defects.

Abstract: A semiconductor device has a semiconductor die with a plurality of composite bumps formed over a surface of the semiconductor die. The composite bumps have a fusible portion and non-fusible portion, such as a conductive pillar and bump formed over the conductive pillar. The composite bumps can also be tapered. Conductive traces are formed over a substrate with interconnect sites having edges parallel to the conductive trace from a plan view for increasing escape routing density. The interconnect site can have a width less than 1.2 times a width of the conductive trace. The composite bumps are wider than the interconnect sites. The fusible portion of the composite bumps is bonded to the interconnect sites so that the fusible portion covers a top surface and side surface of the interconnect sites. An encapsulant is deposited around the composite bumps between the semiconductor die and substrate.

Abstract: The present invention provides a TSV-based oscillator WLP structure and a method for fabricating the same. The method of the present invention comprises steps: providing a silicon base having an oscillator unit disposed thereon; forming on the silicon base at least one package ring surrounding the oscillator unit; and disposing a silicon cap on the package ring to envelop the oscillator unit. The present invention adopts a cap and a base, which are made of the same material, to effectively overcome the problem of thermal stress occurring in a conventional sandwich package structure. Further, the present invention elaborately designs the wiring on the lower surface of the base to reduce the package size and decrease consumption of noble metals.

Abstract: A semiconductor device has a conductive via in a first surface of a substrate. A first interconnect structure is formed over the first surface of the substrate. A first bump is formed over the first interconnect structure. The first bump is formed over or offset from the conductive via. An encapsulant is deposited over the first bump and first interconnect structure. A portion of the encapsulant is removed to expose the first bump. A portion of a second surface of the substrate is removed to expose the conductive via. The encapsulant provides structural support and eliminates the need for a separate carrier wafer when thinning the substrate. A second interconnect structure is formed over the second surface of the substrate. A second bump is formed over the first bump. A plurality of semiconductor devices can be stacked and electrically connected through the conductive via.

Abstract: A structure comprises a top metal connector formed underneath a bond pad. The bond pad is enclosed by a first passivation layer and a second passivation layer. A polymer layer is further formed on the second passivation layer. The dimension of an opening in the first passivation layer is less than the dimension of the top metal connector. The dimension of the top metal connector is less than the dimensions of an opening in the second passivation layer and an opening in the polymer layer.

Abstract: A 3D interconnect structure and method of manufacture are described in which a through-silicon vias (TSVs) and metal redistribution layers (RDLs) are formed using a dual damascene type process flow. A silicon nitride or silicon carbide passivation layer may be provided between the thinned device wafer back side and the RDLs to provide a hermetic barrier and etch stop layer during the process flow.

Abstract: A method of removing oxidation from certain metallic contact surfaces utilizing a combination of relatively simple and inexpensive off-the-shelf equipment and specific chemistry. The method being a very rapid dry process which does not require a vacuum or containment chamber, or toxic gasses/chemicals, and does not damage sensitive electronic circuits or components. Additionally, the process creates a passivation layer on the surface of the metallic contact which inhibits further oxidation while allowing rapid and complete bonding, even many hours after surface treatment, without having to remove the passivation layer. The process utilizes a room-ambient plasma applicator with hydrogen, nitrogen, and inert gasses.

Abstract: A conductive bump structure is formed on a substrate having a plurality of bonding pads and a first insulating layer thereon. The first insulating layer has a plurality of openings formed therein for exposing the bonding pads and a conductive post is formed on the bonding pads exposed through the openings. Therein, a gap is formed between the conductive post and the wall of the opening such that no contact occurs between the conductive post and the first insulating layer, thereby preventing delamination of the conductive bump structure caused by stresses concentrating on an interface of different materials as in the prior art.

Abstract: A bottom source power metal-oxide-semiconductor field-effect transistor (MOSFET) device includes a gate electrode and a source electrode formed on an initial insulation layer on a first surface of a semiconductor chip and a drain electrode formed on a second surface of the semiconductor chip. The source electrode includes a source metal, a source electrode bump formed on the source metal and a source electrode metal layer on top of the source electrode bump. A first insulation layer covers the gate electrode. A through via aligned to the gate electrode is formed from the second surface of the chip to expose a portion of the gate electrode from the second surface.

Abstract: Methods of forming a Ni material on a bond pad are disclosed. The methods include forming a dielectric material over a bond pad, forming an opening within the dielectric material to expose the bond pad, curing the dielectric material to form a surface of the dielectric material having a steep curvilinear profile, and forming a nickel material over the at least one bond pad. The dielectric material having a steep curvilinear profile may be formed by altering at least one of a curing process of the dielectric material and a thickness of the dielectric material. The dielectric material may be used to form a relatively thick Ni material on bond pads smaller than about 50 ?m. Semiconductor structures formed by such methods are also disclosed.

Abstract: The reliability of a semiconductor device is enhanced. A first lead frame, a first semiconductor chip, a second lead frame, and a second semiconductor chip are stacked over an assembly jig in this order with solder in between and solder reflow processing is carried out to fabricate their assembly. Thereafter, this assembly is sandwiched between first and second molding dies to form an encapsulation resin portion. The upper surface of the second die is provided with steps. At a molding step, the second lead frame is clamped between the first and second dies at a position higher than the first lead frame; and a third lead frame is clamped between the first and second dies at a higher position. The assembly jig is provided with steps at the same positions as those of the steps in the upper surface of the second die in positions corresponding to those of the same.

Abstract: A pad structure usable with a semiconductor device may include an insulating layer pattern structure, a plug, and a pad. The insulating layer pattern structure has a plug hole and at least one via hole. The plug is formed in the plug hole. The pad is formed on the insulating layer pattern structure. The pad is electrically connected with the plug and has a lower surface and an uneven upper surface. The lower surface includes a protruded portion inserted into the via hole. The uneven upper surface includes a recessed portion and an elevated portion- to provide high roughness and firm connection.

Abstract: Disclosed herein is a bump-on-trace interconnect with a wetted trace sidewall and a method for fabricating the same. A first substrate having conductive bump with solder applied is mounted to a second substrate with a trace disposed thereon by reflowing the solder on the bump so that the solder wets at least one sidewall of the trace, with the solder optionally wetting between at least half and all of the height of the trace sidewall. A plurality of traces and bumps may also be disposed on the first substrate and second substrate with a bump pitch of less than about 100 ?m, and volume of solder for application to the bump calculated based on at least one of a joint gap distance, desired solder joint width, predetermined solder joint separation, bump geometry, trace geometry, minimum trace sidewall wetting region height and trace separation distance.

Abstract: A semiconductor device has a semiconductor die mounted to a substrate with a plurality of composite interconnects formed between interconnect sites on the substrate and bump pads on the die. The interconnect sites are part of traces formed on the substrate. The interconnect site has a width between 1.0 and 1.2 times a width of the trace. The composite interconnect is tapered. The composite interconnects have a fusible portion connected to the interconnect site and non-fusible portion connected to the bump pad. The non-fusible portion can be gold, copper, nickel, lead solder, or lead-tin alloy. The fusible portion can be tin, lead-free alloy, tin-silver alloy, tin-silver-copper alloy, tin-silver-indium alloy, eutectic solder, or other tin alloys with silver, copper, or lead. An underfill material is deposited between the semiconductor die and substrate. A finish such as Cu—OSP can be formed over the substrate.

Abstract: Provided is a method for chip packaging, including the steps of: providing a semi-packaged wafer which has a cutting trail and a metal bonding pad of the chip; forming a first protective layer on the cutting trail; forming on the metal bonding pad a sub-ball metal electrode; forming a solder ball on the sub-ball metal electrode; dicing the wafer along the cutting trail. The first protective layer according to the present invention can prevent the metal in the cutting trail from being separated by electroplating, and protect the lateral sides of a discrete chip after cutting. The process flow thereof is simple, and enhances the efficiency of the packaging as well as its yield.

Abstract: Methods and apparatus for solder connections. An apparatus includes a substrate having a conductive terminal on a surface; a passivation layer overlying the surface of the substrate and the conductive terminal; an opening in the passivation layer exposing a portion of the conductive terminal; at least one stud bump bonded to the conductive terminal in the opening and extending in a direction normal to the surface of the substrate; and a solder connection formed on the conductive terminal in the opening and enclosing the at least one stud bump. Methods for forming the solder connections are disclosed.

Abstract: A solder bump support structure and method of manufacturing thereof is provided. The solder bump support structure includes an inter-level dielectric (ILD) layer formed over a silicon substrate. The ILD layer has a plurality of conductive vias. The structure further includes a first insulation layer formed on the ILD layer. The solder bump support structure further includes a pedestal member formed on the ILD layer which includes a conductive material formed above the plurality of conductive vias in the ILD layer coaxially surrounded by a second insulation layer. The second insulation layer is thicker than the first insulation layer. The structure further includes a capping under bump metal (UBM) layer formed over, and in electrical contact with, the conductive material and formed over at least a portion of the second insulation layer of the pedestal member.

Abstract: The invention generally relates to a packaging method of an ultra-thin chip, more specifically, the invention relates to a method for packaging the ultra-thin chip with solder ball thermo-compression in wafer level packaging process. The method starts with disposing solder balls on metal pads arranged on the front surface of semiconductor chips that are formed at the front surface of a semiconductor wafer. The solder balls are soften by heating the wafer, a compression plate is applied with a pressure on the top ends of the solder balls thus forming a co-planar top surface at the top ends of the solder balls. A molding compound is deposited on the front surface of the wafer with the top ends of the solder balls exposed. The wafer is then ground from its back surface to reduce its thickness to achieve ultra-thin chip.

Abstract: A method of attaching a die to a substrate is disclosed. A major surface of the die has an array of electrical contacts, and is covered with a tape segment having an array of apertures in register with the contacts. Solder balls are inserted into the apertures. The die is positioned against a substrate with the solder balls in register with the die pads on the surface of the substrate, and a heat treatment process is performed to bond the conductive elements to the corresponding bond pads.

Abstract: A semiconductor package comprises a bond pad formed on a first semiconductor die, a surface of the bond pad exposed through an opening in a passivation layer on the first semiconductor die; a raised conductive area formed on top of a passivation layer on a second semiconductor die; and a bond wire having a first end coupled to the bond pad via a ball bond and a second end coupled directly to a surface of the raised conductive area via a stitch bond. The raised conductive area is comprised of a plurality of metal layers, each of the metal layers comprised of a respective material and having a respective thickness. The thickness and material of at least one of the plurality of metal layers is selected such that a hardness of the raised conductive area is at least as hard as a hardness of the bond wire.

Abstract: A method to realize flux free indium bumping process includes several steps including substrate metallization, contact holes opening, underbump metallization (UBM) layer thickening, indium bump preparation and Ag layer coating. The method can be used in the occasion for some special application, e.g., the packaging of the photoelectric chip (with optical lens), MEMS and biological detection chip, where the usage of flux is prohibited.

Abstract: A chip scale package has a semiconductor die having an array of die bond pads arranged with a bond pad density per unit area, embedded in a molded die support body having a surface supporting an array of conducting contacts, each of the contacts connected by an electrical lead to a corresponding one of the die bond pads.

Abstract: A technique that makes it possible to enhance the reliability of a module using PCB as its module substrate is provided. Solder connection of a single-chip component 43, an integrated chip component 44, and a semiconductor chip IC2 by Pb-free solder is carried out by heat treatment at a temperature below 280° C. using a heat block. Solder connection of a semiconductor chip IC1 by high-melting point solder is carried out by heat treatment at a temperature of 280° C. or higher using a hot jet. Thus, the semiconductor chip IC1 can be solder connected to PCB 38 using high-melting point solder without the following troubles: damage to the PCB 38 due to heat, for example, burning of solder resist; and peeling of prepreg from a core material. Therefore, the semiconductor chip IC1 can be mounted over the PCB 38 with high connection strength.

Abstract: A semiconductor device has a semiconductor die with a plurality of bumps formed over the die. A substrate has a plurality of conductive traces formed on the substrate. Each trace has an interconnect site for mating to the bumps. The interconnect sites have parallel edges along a length of the conductive traces under the bumps from a plan view for increasing escape routing density. The bumps have a noncollapsible portion for attaching to a contact pad on the die and fusible portion for attaching to the interconnect site. The fusible portion melts at a temperature which avoids damage to the substrate during reflow. The noncollapsible portion includes lead solder, and fusible portion includes eutectic solder. The interconnect sites have a width which is less than 1.2 times a width of the conductive trace. Alternatively, the interconnect sites have a width which is less than one-half a diameter of the bump.

Abstract: A packaged microelectronic assembly includes a microelectronic element having a front surface and a plurality of first solid metal posts extending away from the front surface. Each of the first posts has a width in a direction of the front surface and a height extending from the front surface, wherein the height is at least half of the width. There is also a substrate having a top surface and a plurality of second solid metal posts extending from the top surface and joined to the first solid metal posts.

Abstract: A semiconductor device has a semiconductor die with die bump pads and substrate with trace lines having integrated bump pads. A solder mask patch is formed interstitially between the die bump pads or integrated bump pads. The solder mask patch contains non-wettable material. Conductive bump material is deposited over the integrated bump pads or die bump pads. The semiconductor die is mounted over the substrate so that the conductive bump material is disposed between the die bump pads and integrated bump pads. The bump material is reflowed without a solder mask around the integrated bump pads to form an interconnect between the semiconductor die and substrate. The solder mask patch confines the conductive bump material within a footprint of the die bump pads or integrated bump pads during reflow. The interconnect can have a non-fusible base and fusible cap.

Abstract: The invention provides a semiconductor package with a through silicon via (TSV) interconnect and a method for fabricating the same. An exemplary embodiment of the semiconductor package with a TSV interconnect includes a semiconductor substrate. A through hole is formed through the semiconductor substrate. A TSV interconnect is disposed in a through hole. A conductive layer lines a sidewall of the through hole, surrounding the TSV interconnect.

Abstract: The present invention allows for direct chip-to-chip connections using the shortest possible signal path.

Abstract: Methods and apparatus to inhibit cracks and delaminations in a semiconductor chip solder bump and to reduce pad parasitic capacitance are disclosed. In one aspect, a method of manufacturing is provided that includes forming a first insulating layer over plural conductor pads of a semiconductor chip and forming an opening over each of the conductor pads. An individual solder structure is coupled to the insulating layer. The solder structure has a projection in each of the openings and in electrical contact with one of the plural conductor pads.

Abstract: A mmWave electronics package constructed from common Printed Circuit Board (PCB) technology and a metal cover. Assembly of the package uses standard pick and place technology and heat is dissipated directly to a pad on the package. Input/output of mmWave signal(s) is achieved through a rectangular waveguide. Mounting of the electronic package to an electrical printed circuit board (PCB) is performed using conventional reflow soldering processes and includes a waveguide I/O connected to an mmWave antenna. The electronic package provides for transmission of low frequency, dc and ground signals from the semiconductor chip inside the package to the PCB it is mounted on. An impedance matching scheme matches the chip to high frequency board transition by altering the ground plane within the chip. A ground plane on the high frequency board encircles the high frequency signal bump to confine the electromagnetic fields to the bump region reducing radiation loss.

Abstract: A system, method, and computer program product are provided for preparing a substrate post. In use, a first solder mask is applied to a substrate. Additionally, a post is affixed to each of one or more pads of the substrate. Further, a second solder mask is applied to the substrate.

Abstract: Provided is a method for manufacturing a semiconductor device which includes: providing a plurality of semiconductor substrates formed with through holes which penetrate between main surfaces of the substrates and are filled with porous conductors; stacking the plurality of semiconductor substrates while aligning the porous conductors filled in the through holes; introducing conductive ink containing particle-like conductors into the porous conductors of the plurality of stacked semiconductor substrates; and sintering the plurality of stacked semiconductor substrates.

Abstract: A method of manufacture of an integrated circuit packaging system includes: providing a base carrier; forming a conductive post on the base carrier, the conductive post having a top protrusion with a protrusion top side; mounting a base integrated circuit over the base carrier; and forming a base encapsulation over the base integrated circuit, the base encapsulation having an encapsulation top side and an encapsulation recess with the conductive post partially exposed within the encapsulation recess, the encapsulation top side above the protrusion top side.

Abstract: The mechanisms of preparing bump structures described by using patterned anodes may simplify bump-making process, reduce manufacturing cost, and improve thickness uniformity within die and across the wafer. In addition, the mechanisms described above allow forming bumps with different heights to allow bumps to be integrated with elements on a substrate with different heights. Bumps with different heights expand the application of copper post bumps to enable further chip integration.

Abstract: A conductive pillar for a semiconductor device is provided. The conductive pillar is formed such that a top surface is non-planar. In embodiments, the top surface may be concave, convex, or wave shaped. An optional capping layer may be formed over the conductive pillar to allow for a stronger inter-metallic compound (IMC) layer. The IMC layer is a layer formed between solder material and an underlying layer, such as the conductive pillar or the optional capping layer.

Abstract: A die including a first set of power tiles arranged in a first array and having a first voltage; a second set of power tiles arranged in a second array offset from the first array and having a second voltage; a set of power mesh segments enclosed by the second set of power tiles and having the first voltage; a first power rail passing underneath the set of power mesh segments and the first set of power tiles; and a set of vias operatively connecting the power rail with the set of power mesh segments and the first plurality of power tiles.

Abstract: A semiconductor device has a semiconductor die with a plurality of bumps formed over the die. A substrate has a plurality of conductive traces formed on the substrate. Each trace has an interconnect site for mating to the bumps. The interconnect sites have parallel edges along a length of the conductive traces under the bumps from a plan view for increasing escape routing density. The bumps have a noncollapsible portion for attaching to a contact pad on the die and fusible portion for attaching to the interconnect site. The fusible portion melts at a temperature which avoids damage to the substrate during reflow. The noncollapsible portion includes lead solder, and fusible portion includes eutectic solder. The interconnect sites have a width which is less than 1.2 times a width of the conductive trace. Alternatively, the interconnect sites have a width which is less than one-half a diameter of the bump.

Abstract: A semiconductor device has a semiconductor die with an die bump pad and substrate with a trace line and integrated bump pad. Conductive bump material is deposited on the substrate bump pad or die bump pad. The semiconductor die over the substrate so that the bump material is disposed between the die bump pad and substrate bump pad. The bump material is reflowed without a solder mask around the die bump pad or substrate bump pad to form an interconnect. The bump material is self-confined within a footprint of the die bump pad or substrate bump pad. The bump material can be immersed in a flux solution prior to reflow to increase wettability. Alternatively, the interconnect includes a non-fusible base and fusible cap. The volume of bump material is selected so that a surface tension maintains self-confinement of the bump material within the bump pads during reflow.