Sinter-ready multi-layer wire / ribbon bond pads and top-die attachment methods

Abstract

1. A method of manufacturing bond pads for connecting a die to a copper ribbon or copper wire on a printed circuit board, the method comprising: providing a sheet of copper foil having a first major surface opposite a second major surface; providing a sinterable film of metal particles; forming a laminate sheet by laminating the sinterable film to the first major surface; and stamping bond pads from the laminate sheet.

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a bond pad for connecting a die to a copper ribbon or copper wire, a bond pad, a sinterable silver film, a method for connecting a die to a copper wire and / or copper ribbon, a method for manufacturing an electronic device, an electronic device, and an assembly method. [Background technology]

[0002] In conventional power modules, for example, the bond wires connecting the semiconductor / die and the substrate are typically formed from aluminum. As the power density requirements of power modules increase, manufacturers are beginning to use copper bond wires, which provide additional current carrying capacity as well as better thermal conduction and heat dissipation. The conditions for welding the copper wires to the semiconductor / die tend to be more severe than for aluminum wires, which can cause damage to the underlying semiconductor / die. As a result, it is common to attach a thin film of copper, known as a "bond pad," to the top surface of the die. The bond pads can provide uniform current distribution (e.g., under short circuit conditions) and better heat dissipation, avoiding substantial damage to the underlying die when the die is welded to the copper wires.

[0003] The technique described in US Pat. No. 10,079,219 B2 involves a flexible contact film (bond pads) sintered onto areas of various thicknesses of a sintered layer applied to the top side of a die or other substrate. The sintered material is applied in a paste form, dried in a wave-like pattern, and sintered into a metal compact. Furthermore, wires or ribbons are ultrasonically welded to the flexible contact film. The implementation of such a technique in mass production of semiconductor devices presents significant challenges. For example, the application of the sintered layer is typically done by stencil, screen, or other type of printing. Printing small areas such as the top side of a die is a difficult and poorly controlled process. Misprints or paste bleed-out frequently occur and can damage the device by shorting electrical terminals or by creating other defects. Furthermore, the top side of the die is usually patterned with the help of a dielectric barrier layer, which protrudes only 10-15 microns above the surface, further complicating the printing process. Producing reproducible paste deposits of varying thicknesses on dies as small as 5x5mm is not achievable in a High Volume Manufacturing (HVM) environment.

[0004] Instead of applying sinter paste to the top side of the die, it is possible to provide the sinter paste at the base of the bond pads. This can be achieved by printing the sinter paste on the base, or by applying the paste to a copper foil and then cutting the copper foil into individual bond pads. The former is susceptible to the problems mentioned above, while the latter may require the use of precise cutting, for example with a laser. This may make the manufacturing method more complicated. Furthermore, the final bond pads may not be robust enough to be handled using traditional tape-and-reel techniques, which may require the use of dicing tape instead. Summary of the Invention

[0005] The present invention aims to solve at least some of the problems associated with the prior art, or to provide a commercially acceptable alternative.

[0006] In a first aspect, the present invention provides a method of manufacturing a bond pad for connecting a die to a copper ribbon or copper wire, the method comprising: Providing a sheet of copper foil having a first major surface opposite a second major surface; Providing a sinterable film of metal particles; laminating a sinterable film to a first major surface to form a laminate sheet; and stamping bond pads from the laminate sheet.

[0007] Each aspect or embodiment defined in this specification may be combined with any other aspect or embodiment unless expressly indicated otherwise. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature indicated as being preferred or advantageous.

[0008] The method may result in bond pads having high quality bond lines between the copper foil and the sinterable film. Advantageously, compared to conventional methods, the method of the present invention may be simpler. In particular, the method may not require the use of precise printing and / or cutting techniques.

[0009] Compared to conventional bond pads, bond pads produced using the present methods can be more robust, and therefore easier to handle without damage, thereby requiring less consideration during their use in methods of manufacturing electronic devices such as power modules or printed circuit boards.

[0010] The bond pads are for connecting the die to copper ribbons or copper wires. This may be in a power module or in a printed circuit board. In other words, the bond pads may be for connecting the die to copper ribbons or copper wires in a power module and / or for connecting the die to copper ribbons or copper wires in a printed circuit board. That is, the copper ribbons or copper wires may be interconnects, i.e., copper ribbon interconnects or copper wire interconnects.

[0011] The bond pads may be suitable for storage in waffle packs or tapes typically used in pick-and-place equipment, and therefore may be particularly suitable for use in high speed manufacturing lines.

[0012] The method includes providing a sheet of copper foil having a first major surface opposite a second major surface. By "first major surface" and "second major surface" we mean the two sides of the sheet, i.e., the two surfaces having the largest area.

[0013] The method includes providing a sinterable film of metal particles. By "sinterable" it is meant that the film is capable of undergoing sintering upon application of heat and / or pressure to form a metallurgical bond between two surfaces. The sinterable film is self-supporting. In other words, the sinterable film is capable of substantially retaining its integrity when handled. This distinguishes the film from a dry layer of sintering paste applied to a surface, which would otherwise be prone to breaking if handled or moved from one surface to another. The sinterable film includes metal particles. The sinterable film may include species other than metal particles. The metal particles may be in the form of one or more of spheres, rods, and plates. The metal particles may include nanoparticles, i.e., have an average longest dimension of 1 to 1000 microns, as measured using TEM or laser diffraction. Examples of suitable sinterable films and methods for their manufacture are described in U.S. Pat. Nos. 10,535,628 B2 and 10,710,336 B2, the disclosures of which are incorporated herein by reference. A commercially available example of a suitable sinterable film is MacDermid Alpha sinter ready film.

[0014] The method includes forming a laminate sheet by laminating a sinterable film to a first major surface. The laminate sheet thus includes a sinterable film and a sheet of copper foil. The sinterable film is laminated onto the first major surface. The sinterable film is not also laminated onto the second major surface. Indeed, the second major surface is typically left uncoated. This allows the copper foil to be welded to a copper ribbon or copper wire.

[0015] The method involves punching the bond pads from the laminate sheet. Punching techniques and punching equipment are known in the art. A commercial example of a suitable punch press is the Lingshen punching press. Suitable punch presses are also provided by Kaka Industry, Samhoor, etc. Punching is sometimes referred to in the art as "stamping".

[0016] The copper foil preferably comprises copper or a copper alloy and / or is preferably of multi-layer construction, which can provide particularly effective bonding bond pads.

[0017] The copper foil preferably has a thickness of 10 to 200 μm, more preferably 50 to 150 μm. Thicker foils may increase the cost of the process and / or excessively increase the thickness of the bond pads, thereby excessively increasing the size of the printed circuit board or power module formed using the bond pads. Thinner foils may damage the underlying die when the copper ribbon or wire is welded to the copper foil. However, the copper foil preferably has a thickness of less than 50 μm, and may have a thickness of, for example, less than 10 μm to 50 μm.

[0018] The copper foil preferably has a hardness HV of 50-100 using a load of 300 g. Higher hardness values ​​may make it more difficult to weld the copper ribbon or copper wire to the copper foil. Lower hardness values ​​may damage the underlying die when the copper ribbon or wire is welded to the copper foil.

[0019] The copper foil is preferably 10 to 20 K. -1 This allows for avoiding undesirable levels of thermal stress during sintering and / or welding.

[0020] The copper foil may be non-perforated. Alternatively, the copper foil is preferably perforated. During use, this can provide stress relief to a device containing the bond pads. In this regard, the copper foil may include a plurality of perforations and / or may be porous and / or mesh-like.

[0021] The metal particles preferably comprise one or more of silver particles, copper particles, silver-coated copper particles, copper-coated silver particles, gold particles, palladium particles, aluminum particles, silver-palladium alloy particles, and gold-palladium alloy particles, more preferably silver particles. The metal particles preferably have a longest dimension of 1 to 1000 nm.

[0022] The sinterable film preferably comprises silver particles having a longest dimension of 1-1000 nm and a polymer binder. Silver particles can exhibit particularly favorable sintering properties and can result in sintered joints with particularly favorable electrical and thermal conductivity. Smaller particles can be more difficult to handle. Larger particles can require unfavorably high sintering temperatures and / or pressures, which can reduce the energy efficiency of the process and / or cause damage to the die or substrate. If the silver particles are in the form of spheres, the longest dimension is the diameter of the spheres. The longest dimension can be measured using TEM or laser diffraction. The use of a binder can ensure that the film is "self-supporting".

[0023] The sinterable film preferably comprises 0.1 to 2 wt % polymer binder, preferably 0.5 to 1 wt % polymer binder, based on the total weight of the sinterable silver film.

[0024] The polymeric binder preferably comprises an amide polymer, more preferably poly(N-vinylacetamide), such species being particularly effective binders.

[0025] The silver particles (or metal particles) preferably have a longest dimension of 5-500 nm, preferably 10-100 nm, more preferably 30-60 nm. This may result in particularly favourable sintering and handling properties. The longest dimension may be measured using TEM or laser diffraction.

[0026] Preferably, the silver particles (or metal particles) in the sinterable film form fine particles having a D90 of 1000 nm or less, preferably 500 nm or less, more preferably 100 nm or less, even more preferably 60 nm or less, and / or a D10 of 1 nm or more, more preferably 5 nm or more, even more preferably 10 nm or more, even more preferably 30 nm or more. Such a particle size distribution may result in particularly favorable sintering and handling properties.

[0027] The sinterable film preferably comprises 90-99 wt. % silver particles (or metal particles), more preferably 92-98 wt. % silver particles (or metal particles), and even more preferably 94-96 wt. % silver particles (or metal particles), based on the total weight of the sinterable film. Higher levels of particles may result in a sinterable film that exhibits unfavorable mechanical / handling properties. Lower levels of particles may allow high levels of species other than silver (e.g., binder or residues thereof) to be present in the final sintered joint, thereby adversely affecting its mechanical and / or electrical and / or thermal properties.

[0028] The sinterable film preferably includes a halogenated alcohol activator having a melting point between 80 and 150°C. Such sinterable films may be particularly useful in bonding bond pads to a die in electronic device manufacturing processes. Surprisingly, the inventors have found that the sinterable silver film may be "hot tacked" to the die during the process of connecting the die to copper wire or copper ribbon. This avoids the possibility of employing an adhesive, the residue of which may be present in the final sintered bond and reduce the integrity of the final sintered bond.

[0029] As used herein, the term "hot tacking" can encompass the process of attaching a sinterable film to a surface by the application of heat and typically also pressure. Such attachment occurs without substantial sintering of metal particles in the sintered film. Thus, the sinterable film can remain in a desired position during the attachment method while retaining the ability to form a bond between the bond pad and the surface of the die. Without wishing to be bound by theory, it is believed that hot tacking is accomplished by limited metal diffusion between the sinterable film and the surface to which the film is "tacked," such as the top surface of the die.

[0030] The presence of a halogenated alcohol activator can remove oxides from the surface to which the sinterable film is to be tacked, such as the top surface of a die. This can ensure that tacking can occur at a temperature sufficient to attach the sinterable film to the surface, but low enough to avoid substantial sintering of the metal particles contained in the sinterable film. Without being bound by theory, it is believed that this may be due to an increased level of metal diffusion that is possible as a result of the removal of surface oxides.

[0031] Furthermore, the presence of a halogenated alcohol activator may make it easier to laminate the first major surface with a sinterable film, and may mean that such lamination may be carried out under milder conditions. Furthermore, the use of a metal plating layer (such as a silver plating layer) on the first major surface, which would otherwise facilitate metal diffusion during lamination, may not be required.

[0032] The sinterable film preferably comprises 0.05 to 1 weight percent halogenated alcohol activator, and more preferably 0.1 to 0.2 weight percent halogenated alcohol activator, based on the total weight of the sinterable film.

[0033] The halogenated alcohol activator preferably has a melting point between 85-140° C., more preferably between 90-130° C., and even more preferably between 100-120° C. This allows the activator to be "active" at typical lamination and / or hot tacking temperatures. At lower temperatures, the activator is a solid, which means that there is no change in the mechanical properties of the sinterable film as a result of melting of the activator that affects its ability to be handled.

[0034] The halogenated alcohol activator has a molecular weight of at least 150, preferably at least 200, and / or up to 500, preferably up to 400, more preferably up to 300, and / or from 150-500, preferably from 200-300.

[0035] The halogenated alcohol preferably comprises a brominated alcohol, more preferably The halogenated alcohols preferably include dibrominated alcohols. The halogenated alcohols preferably include 3 to 5 carbon atoms. The halogenated alcohols preferably include monohydroxy alcohols. The halogenated alcohols may be linear or branched. The halogenated alcohols preferably include 3,4-dibromo-2-butanol and / or 1,4-dibromobutan-2-ol. Such alcohols may be particularly effective in removing surface oxides.

[0036] The sinterable film preferably further comprises partially hydrogenated gum rosin, preferably in an amount of 0.1 to 0.3 wt. %, based on the total weight of the sinterable silver film, and / or micronized wax, preferably in an amount of 0.2 to 0.4 wt. %, based on the total weight of the sinterable silver film.

[0037] Laminating the first major surface with a sinterable film preferably includes contacting the sinterable film with the first surface and applying heat and pressure to the sheet of copper foil and sinterable film.

[0038] The first surface preferably includes a metal plating layer, and contacting the sinterable film with the first surface preferably includes contacting the metal plating layer with a sinterable silver film. This allows lamination to be performed at lower temperatures and / or pressures. Without being bound by theory, this may be because metal diffusion between the metal particles and the metal plating layer may be more significant than between the metal particles and the copper foil.

[0039] The metal plating layer preferably comprises silver, nickel-gold alloy and / or ENIG, more preferably silver. If the sinterable film comprises silver particles, the metal plating layer preferably comprises silver. The diffusion of silver into the silver plating layer may be more significant than the diffusion into the copper foil.

[0040] The metal plating layer preferably has a thickness of 1 to 5 μm. A thinner thickness may not adequately promote metal diffusion. A thicker thickness may excessively increase the size of the device formed using the bond pad.

[0041] Applying heat and pressure to the copper foil and the sheet of sinterable film preferably includes applying a pressure of at least 0.5 MPa, preferably at least 0.8 MPa, more preferably 0.5-2 MPa, even more preferably 0.8-1.2 MPa, and even more preferably about 1 MPa, and / or heating the copper foil and / or the sheet of sinterable film to a temperature of 100-200° C., preferably 120-170° C., even more preferably 140-160° C., and even more preferably about 150° C., preferably for 1-60 seconds, more preferably 2-40 seconds, even more preferably 5-15 seconds, and even more preferably about 10 seconds. This may result in an adequate level of adhesion between the sheet of copper foil and the sinterable film without causing substantial sintering of the sinterable film.

[0042] Preferably, the method further includes applying an adhesive to the sinterable film on the laminate sheet, and die-cutting is performed such that the adhesive is present on the sinterable film on the bond pad. This may allow for "cold tacking" of the bond pad to the die, i.e., tacking at temperatures below 100°C or below 90°C. This may be beneficial when the die is attached to a substrate that may be damaged and / or oxidized at higher temperatures. The adhesive may be applied in any shape, but is typically applied in multiple separate areas. In other words, multiple separate tack deposits may be applied. Following die-cutting, each bond pad may include, for example, 1-4 separate tack deposits. The tack may be applied using hot melt jetting using commercially available equipment such as a Nordson Unity PJ30XT. The adhesive is preferably applied before die-cutting, as it is easier to apply to a continuous strip, but the adhesive may be applied after die-cutting.

[0043] The adhesive preferably comprises a diphenyl compound, preferably having a melting point of 50-90°C, and / or a triphenyl compound, preferably having a melting point of 50-90°C, and / or a fatty alcohol, preferably having a melting point of 30-60°C. In a preferred embodiment, the adhesive comprises a polyvinyl ether. Such species exhibit a high level of "tackiness" at typical cold tacking temperatures, but a limited level of tackiness at lower temperatures, which can make them easier to handle. Such species may be substantially vaporized at typical sintering temperatures, meaning that such species are substantially absent from the final sintered joint.

[0044] In a further aspect, the present invention provides a bond pad manufactured according to the methods described herein.

[0045] The advantages and preferred features of the first aspect apply equally to this aspect.

[0046] In a further aspect, the present invention provides a method for producing a composition comprising the steps of: Silver particles having a longest dimension between 1 and 1000 nm; A polymer binder; and a halogenated alcohol activator having a melting point of 80 to 150°C.

[0047] The advantages and preferred features of the first aspect apply equally to this aspect. The sinterable film may be particularly suitable for attaching bond pads to a die.

[0048] The silver particles preferably have a longest dimension of from 5 to 500 nm, preferably from 10 to 100 nm, more preferably from 30 to 60 nm.

[0049] The silver particles in the sinterable silver film preferably form fine particles having a D90 of 1000 nm or less, preferably 500 nm or less, more preferably 100 nm or less, even more preferably 60 nm or less, and / or a D10 of 1 nm or more, preferably 5 nm or more, more preferably 10 nm or more, even more preferably 30 nm or more.

[0050] The sinterable silver film preferably comprises 90-99 wt. % silver metal particles, more preferably 92-98 wt. % silver metal particles, and even more preferably 94-96 wt. % silver metal particles, based on the total weight of the sinterable film.

[0051] The sinterable silver film preferably comprises 0.1 to 2 wt % polymer binder, more preferably 0.5 to 1 wt % polymer binder, based on the total weight of the sinterable silver film.

[0052] The polymer binder preferably comprises an amide polymer, more preferably poly(N-vinylacetamide).

[0053] The sinterable silver film preferably comprises 0.05 to 1 wt % halogenated alcohol activator, and more preferably 0.1 to 0.2 wt % halogenated alcohol activator, based on the total weight of the sinterable silver film.

[0054] The halogenated alcohol activator preferably has a melting point of 85 to 140°C, more preferably 90 to 130°C, and even more preferably 100 to 120°C.

[0055] The halogenated alcohol activator preferably has a molecular weight of at least 150, preferably at least 200 and / or up to 500, preferably up to 400, more preferably up to 300, and / or from 150-500, preferably from 200-300.

[0056] The halogenated alcohol preferably comprises a brominated alcohol, more preferably a dibrominated alcohol. The halogenated alcohol preferably comprises 3 to 5 carbon atoms. The halogenated alcohol preferably comprises a monohydroxy alcohol. The halogenated alcohol preferably comprises 3,4-dibromo-2-butanol and / or 1,4-dibromobutan-2-ol.

[0057] The sinterable silver film comprises partially hydrogenated gum rosin, preferably in an amount of 0.1 to 0.3 wt. %, based on the total weight of the sinterable silver film, and / or micronized wax, preferably in an amount of 0.2 to 0.4 wt. %, based on the total weight of the sinterable silver film.

[0058] In a further aspect, the present invention provides a bond pad for connecting a die to a copper wire or copper ribbon, the bond pad comprising: Copper foil and a sinterable silver film as described herein laminated onto a copper foil; Optionally, a metal plating layer sandwiched between the copper foil and the sinterable silver film.

[0059] The advantages and preferred features of the first aspect apply equally to this aspect.

[0060] The copper foil preferably comprises copper or a copper alloy and / or is preferably of multi-layer construction.

[0061] The copper foil preferably has a thickness of 10 to 200 μm, more preferably 50 to 150 μm.

[0062] The copper foil preferably has a hardness Hv of 50-100.

[0063] Copper foil is 10~20K -1 Preferably, the material has a coefficient of thermal expansion (CTE) of 0.1 to 0.5.

[0064] The copper foil is preferably perforated.

[0065] The metal plating layer preferably comprises silver, a nickel-gold alloy, and / or ENIG (electroless nickel immersion gold).

[0066] The metal plating layer preferably has a thickness of 1 to 5 μm.

[0067] The bond pad preferably further comprises an adhesive on the outer surface of the sinterable silver film.

[0068] The adhesive preferably comprises a diphenyl compound having a melting point of preferably 50 to 90°C, and / or a triphenyl compound having a melting point of preferably 50 to 90°C, and / or a fatty alcohol having a melting point of preferably 30 to 60°C.

[0069] The adhesive preferably comprises a polyvinyl ether.

[0070] In a further aspect, the present invention provides a method of connecting a die to copper wire and / or copper ribbon, the method comprising: Providing a die; Providing a bond pad as described herein; contacting the sinterable film of the bond pad with the die; heating the sinterable film to connect the bond pads to the die; and welding the copper wire and / or copper ribbon to the copper foil of the bond pad.

[0071] The advantages and preferred features of the first aspect apply equally to this aspect.

[0072] References to a sinterable film correspond to either a sinterable silver film or a sinterable film of metal particles, depending on which bond pad (embodiment of the invention) is used. Contacting the sinterable film of the bond pad with the die may be performed using standard die pick and place equipment, such as, for example, a Datacon 2200 EVO or an Infotech Die Bonder.

[0073] The welding preferably comprises ultrasonic welding and / or laser welding, which may be capable of forming a particularly strong connection between the die / bond pads and the copper wires and / or copper ribbons.

[0074] Welding the copper wire and / or copper ribbon to the copper foil of the bond pad typically includes welding the copper wire and / or copper ribbon to the second major surface of the copper foil.

[0075] Heating the sinterable film to connect the bond pad to the die typically involves sintering the sinterable film, thereby forming a metallurgical bond between the bond pad and the die.

[0076] Heating is preferably carried out at a temperature of 200-300° C., more preferably 220-280° C., even more preferably 240-260° C. Higher temperatures can cause damage to the die or the substrate to which the die is attached. Lower temperatures can result in insufficient sintering of the sinterable film, resulting in weak bonds.

[0077] Heating is preferably carried out at a pressure of 2-20 MPa, more preferably 5-15 MPa, even more preferably 8-12 MPa, and even more preferably about 10 MPa. Higher pressures can cause damage to the die or the substrate to which the die is attached. Lower pressures can result in insufficient sintering of the sinterable film, resulting in weak bonds.

[0078] Heating is preferably carried out for 10 to 180 seconds, more preferably 30 to 120 seconds, even more preferably 50 to 100 seconds, and even more preferably 60 to 90 seconds. Longer times are unnecessary and do not result in any greater level of adhesion. Shorter times may result in insufficient sintering of the sinterable film, resulting in weak bonds.

[0079] The die preferably includes a metallized surface, more preferably including silver, gold and / or palladium, and contacting the sinterable film of the bond pad with the die includes contacting the sinterable film of the bond pad with the metallized surface of the die, which may strengthen the bond.

[0080] Contacting the sinterable film of the bond pad with the die preferably includes preheating the die to a temperature of 130-180° C. and contacting the preheated die with the sinterable film with a force of 50-150 N, more preferably 70-130 N, even more preferably 80-100 N, even more preferably about 90 N, and / or a placement time of 100-2000 ms, more preferably 200-1000 ms. The application of such heat and pressure promotes limited metal diffusion between the sinterable film and the die, thereby fixing the bond pad to the die (so-called "hot tacking"). Thus, the bond pad can be held in a desired position during the method.

[0081] Preferably, the die includes an adhesive on its surface, and contacting the sinterable film of the bond pad with the die includes contacting the sinterable film of the bond pad with the adhesive, and contacting the sinterable film of the bond pad with the die is performed using a pick-and-place tool preheated to 50-90°C. The adhesive can hold the bond pad in the desired position during this process (so-called "cold tacking"). This may be achieved at a lower temperature (e.g., room temperature) than "hot tacking", which may be beneficial if the die and / or the substrate to which the die is attached may be damaged at higher temperatures. Typically, the adhesive is "tacky" at the temperature of the pick-and-place machine. Placement times may be short, e.g., as short as 50-100 milliseconds, which may allow for high production rates.

[0082] In a further aspect, the present application provides a method of manufacturing an electronic device comprising connecting a die to copper wires and / or copper ribbons according to the methods described herein.

[0083] The advantages and preferred features of the first aspect apply equally to this aspect.

[0084] In a further aspect, the present invention provides an electronic device manufactured according to the methods described herein.

[0085] The advantages and preferred features of the first aspect apply equally to this aspect.

[0086] In a further aspect, the present invention provides electronic devices comprising and / or manufactured with the bond pads described herein.

[0087] The advantages and preferred features of the first aspect apply equally to this aspect.

[0088] The electronic device preferably comprises a power device or module.

[0089] The electronic device preferably further comprises a substrate connected to the die via the sintered silver film.

[0090] In a further aspect, the present invention provides a method of manufacturing a bond pad as described herein, the method comprising: Providing a copper foil; Providing a sinterable silver film as described herein; contacting a copper foil with a sinterable silver film; applying heat and pressure to the copper foil and the sinterable silver film to laminate the sinterable silver film onto the copper foil to provide a laminated copper foil; and stamping bond pads from the laminated copper foil.

[0091] The advantages and preferred features of the first aspect apply equally to this aspect.

[0092] The sinterable silver film preferably includes a metal plating layer, and contacting the copper foil with the sinterable silver film includes contacting the metal plating layer with the sinterable silver film.

[0093] Applying heat and pressure to the copper foil and sinterable silver film preferably comprises applying a pressure of at least 0.5 MPa, preferably at least 0.8 MPa, more preferably 0.5-2 MPa, even more preferably 0.8-1.2 MPa, and even more preferably about 1 MPa, and / or heating the copper foil and / or sinterable silver film to a temperature of 100-200°C, preferably 120-170°C, even more preferably 140-160°C, and even more preferably about 150°C, preferably for 1-60 seconds, more preferably 2-40 seconds, even more preferably 5-15 seconds, and even more preferably about 10 seconds.

[0094] In a further aspect, the present invention provides a method for producing a composition comprising the steps of: providing a substrate having a die thereon, the substrate and the die being separated by a sinterable film; Providing a bond pad as described herein; contacting the bond pad to the die through the sinterable film on the bond pad; sintering the sinterable film; and Providing a copper ribbon or copper wire; and connecting the copper ribbon or wire to the die and optionally to the substrate.

[0095] The advantages and preferred features of the first aspect apply equally to this aspect.

[0096] Providing the bond pads preferably includes providing the bond pads on a tape and reel assembly, and contacting the bond pads with the die is preferably performed using a pick and place machine. Sintering may be performed, for example, in a sintering press. Sintering conditions may include, for example, a pressure of 1 to 15 MPa (e.g., 10 MPa), a temperature of 200 to 300°C (e.g., 250°C), and a time of 1 to 180 seconds (e.g., 60 to 90 seconds).

[0097] In a further aspect, the present invention provides a bond pad for connecting a die to a copper wire or copper ribbon, the bond pad comprising: A copper foil having a metal plating layer; and a sinterable silver film as described herein laminated onto the metal plating layer.

[0098] The advantages and preferred features of the first aspect apply equally to this aspect.

[0099] The invention will now be further described with reference to the following numbered clauses:

[0100] 1. A sinterable silver film comprising: Silver particles having a longest dimension between 1 and 1000 nm; A polymer binder; and a halogenated alcohol activator having a melting point of 80 to 150°C.

[0101] The longest dimension is measured, for example, by TEM. The particles may be in the form of, for example, spheres, plates, rods. If the particles are in the form of spheres, the longest dimension is the diameter of the sphere.

[0102] 2. The sinterable silver film of clause 1, wherein the silver particles have a longest dimension of 5 to 500 nm, preferably 10 to 100 nm, and more preferably 30 to 60 nm.

[0103] 3. The sinterable silver film according to clause 1 or clause 2, comprising 0.1 to 2 wt. % of a polymer binder, preferably 0.5 to 1 wt. % of a polymer binder, based on the total weight of the sinterable silver film.

[0104] 4. The sinterable silver film according to any one of clauses 1 to 3, wherein the polymer binder comprises an amide polymer, preferably poly(N-vinylacetamide).

[0105] 5. The sinterable silver film of any one of clauses 1 to 4, comprising 0.05 to 1 wt. % of a halogenated alcohol activator, preferably 0.1 to 0.2 wt. %, based on the total weight of the sinterable silver film.

[0106] 6. The sinterable silver film according to any one of clauses 1 to 5, wherein the halogenated alcohol activator has a melting point of 85 to 140°C, preferably 90 to 130°C, more preferably 100 to 120°C.

[0107] 7. The sinterable silver film of any one of clauses 1-6, wherein the halogenated alcohol activator has a molecular weight of at least 150, preferably at least 200, more preferably at least 300, even more preferably at least 400, and even more preferably at least 500.

[0108] 8. The sinterable silver film of any one of clauses 1 to 7, wherein the halogenated alcohol comprises a brominated alcohol.

[0109] 9. The sinterable silver film according to any one of clauses 1 to 8, wherein the halogenated alcohol contains 3 to 5 carbon atoms.

[0110] 10. The sinterable silver film according to any one of clauses 1 to 9, wherein the halogenated alcohol is linear or branched.

[0111] 11. The sinterable silver film according to any one of clauses 1 to 10, wherein the halogenated alcohol comprises 3,4 dibromo-2-butanol and / or 1,4 dibromobutan-2-ol.

[0112] 12. Partially hydrogenated gum rosin, preferably in an amount of 0.1 to 0.3% by weight based on the total weight of the sinterable silver film, and / or Further comprising finely divided wax, preferably in an amount of 0.2 to 0.4 wt. %, based on the total weight of the sinterable silver film. 12. The sinterable silver film according to any one of clauses 1 to 11.

[0113] 13. Bond pads for connecting the die to copper wires or copper ribbons, Copper foil and 13. A sinterable silver film according to any one of clauses 1 to 12 laminated onto a copper foil; Optionally, the bond pad comprises a metal plating layer sandwiched between a copper foil and a sinterable silver film.

[0114] 14. The bond pad of claim 13, wherein the copper foil comprises copper or a copper alloy and / or is a multi-layer structure.

[0115] 15. The bond pad of clause 13 or clause 14, wherein the copper foil has a thickness of 10 to 200 μm, preferably 50 to 150 μm.

[0116] 16. The bond pad of any one of clauses 13-15, wherein the copper foil has a hardness Hv of 50-100.

[0117] 17. The bond pad of any one of clauses 13-16, wherein the copper foil has a coefficient of thermal expansion (CTE) of 10-20 ppm.

[0118] 18. The bond pad of any one of clauses 13-17, wherein the copper foil is perforated.

[0119] 19. The bond pad of any one of clauses 13-18, wherein the metal plating layer comprises silver, nickel-gold alloy and / or ENIG (electroless nickel immersion gold).

[0120] 20. The bond pad of any one of clauses 13-19, wherein the metal plating layer has a thickness of 1-5 μm.

[0121] 21. The bond pad of any one of clauses 13-20, further comprising an adhesive on an outer surface of the sinterable silver film.

[0122] 22. The adhesive is A diphenyl compound preferably having a melting point of 50 to 90° C., and / or A triphenyl compound preferably having a melting point of 50 to 90° C., and / or 22. The bond pad of claim 21, comprising a fatty alcohol preferably having a melting point of 30-60°C.

[0123] 23. The bond pad of clause 21 or clause 22, wherein the adhesive comprises polyvinyl ether.

[0124] 24. A method for connecting a die to copper wire and / or copper ribbon, comprising: Providing a die; Providing a bond pad according to any one of clauses 13-23; contacting the sinterable silver film of the bond pad with a die; heating the sinterable silver film to connect the bond pads to the die; and welding the copper wire and / or copper ribbon to the copper foil of the bond pad.

[0125] 25. The method of claim 24, wherein the welding comprises ultrasonic and / or laser welding.

[0126] 26. The method according to clause 24 or clause 25, wherein the heating is carried out at a temperature of 200 to 300°C, preferably 220 to 280°C, more preferably 240 to 260°C.

[0127] 27. The method according to any one of clauses 24 to 26, wherein the heating is carried out under a pressure of 2 to 20 MPa, preferably 5 to 15 MPa, more preferably 8 to 12 MPa, even more preferably about 10 MPa.

[0128] 28. The method according to any one of clauses 24 to 27, wherein the heating is carried out for 10 to 180 seconds, preferably 30 to 120 seconds, more preferably 50 to 100 seconds, and even more preferably 60 to 90 seconds.

[0129] 29. The method of any one of clauses 24-28, wherein the die comprises a metallized surface, preferably comprising silver, gold and / or palladium, and contacting the sinterable silver film of the bond pad with the die comprises contacting the sinterable silver film of the bond pad with the metallized surface of the die.

[0130] 30. Contacting the sinterable silver film of the bond pad with the die is Preheating the die to a temperature of 130 to 180°C; 30. The method according to any one of clauses 24-29, comprising contacting the pre-heated die with a force of 50-150N, preferably 70-130N, more preferably 80-100N, even more preferably about 90N, and / or a placement time of 100-2000ms, preferably 200-1000ms.

[0131] 31. The method of any one of clauses 24-30, wherein contacting the sinterable silver film of the bond pad with the die is performed using a pick and place tool that is preheated to 50-90°C.

[0132] 32. The method of any one of clauses 24-31, wherein the die includes an adhesive on a surface thereof, and contacting the sinterable silver film of the bond pad with the die includes contacting the sinterable silver film of the bond pad with the adhesive.

[0133] 33. A method of manufacturing an electronic device comprising connecting a die to copper wire and / or copper ribbon according to the method of any one of clauses 24 to 32.

[0134] 34. Electronic devices manufactured in accordance with clause 33.

[0135] 35. An electronic device comprising and / or manufactured with a bond pad according to any one of clauses 13-23.

[0136] 36. An electronic device according to clause 34 or clause 35, wherein the electronic device is a power device or a power module.

[0137] 37. a copper wire or ribbon welded to a copper foil; 37. The electronic device of any one of clauses 34 to 36, further comprising a substrate connected to the die via a sintered silver film.

[0138] 38. A method for manufacturing a bond pad according to any one of clauses 13 to 23, comprising: Providing a copper foil; Providing a sinterable silver film; contacting a copper foil with a sinterable silver film; applying heat and pressure to the copper foil and the sinterable silver film to laminate the sinterable silver film onto the copper foil to provide a laminated copper foil; stamping bond pads from the laminated copper foil; Sinterable silver films are Silver particles having a longest dimension between 1 and 1000 nm; A polymer binder; and a halogenated alcohol activator having a melting point of 80 to 150°C.

[0139] 39. The method of claim 38, wherein the sinterable silver film comprises a metal plating layer, and contacting the copper foil with the sinterable silver film comprises contacting the metal plating layer with the sinterable silver film.

[0140] 40. Applying heat and pressure to the copper foil and sinterable silver film applying a pressure of at least 0.5 MPa, preferably at least 0.8 MPa, more preferably between 0.5 and 2 MPa, even more preferably between 0.8 and 1.2 MPa, even more preferably at about 1 MPa; and / or The copper foil and / or the sinterable silver film is heated to a temperature of 100 to 200° C., preferably 120 to 170° C., more preferably 140 to 160° C., and even more preferably about 150° C. 40. The method of claim 38 or 39, comprising heating for preferably from 1 to 60 seconds, more preferably from 2 to 40 seconds, even more preferably from 5 to 15 seconds, and even more preferably about 10 seconds. [Brief description of the drawings]

[0141] The invention will now be further described with reference to the following drawings. [Figure 1] 1 is a schematic diagram of a bond pad according to the present invention. [Diagram 2] 1 is a schematic diagram of an electronic device according to the present invention; [Diagram 3] 1 is a schematic diagram of an electronic device according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0142] Referring to Figure 1, a bond pad (generally 1) in accordance with the present invention is shown. The bond pad includes a copper foil 2 having a plating layer 3 on its surface. A sinterable silver film 4 is laminated onto the copper foil 2 via the plating layer 3. An adhesive 5 is located on the outer surface of the sinterable silver film 4.

[0143] Referring to Figure 2, an electronic device (generally 6) according to the present invention is shown. A bond pad 1 according to the present invention is attached to a die 7 via a sinterable silver film (not shown) on the bond pad. The die 7 is attached to a substrate 9 via a sinterable silver film 8. The substrate includes a ceramic core 10 and a copper surface layer 11. A copper wire 12 is welded to the bond pad 1 and to the top surface of the copper surface layer 11.

[0144] The invention will now be further described with reference to the following examples. EXAMPLES

[0145] An electronic device was fabricated in the following manner: A substrate having a die thereon was provided, the substrate and die separated by a sinterable film. A 50 μm thick bond pad was prepared comprising a metal plated rigid copper foil with a sinterable silver film laminated thereon. The bond pad was placed on the top surface of the die via the sinterable film. The resulting blank was transferred to an oven where the sinterable film was sintered to form metal bonds between the bond pad and the top surface of the die, and between the die and the substrate. A copper ribbon was then ultrasonically welded to the top surface of the body pad. The result is shown in FIG. 3, where the bond pad is indicated at 13, the die is indicated at 14, the substrate is indicated at 15, and the copper ribbon is indicated at 16.

[0146] An identical electronic device was prepared except that the copper foil comprised soft copper.

[0147] The connections between the bond pads and copper ribbons of both devices were subjected to shear testing using industry accepted shear testing as described in Technical Bulletin DVS 2811. The results are as follows:

[0148] [Table 1]

[0149] In both cases the shear strength was excellent, well above the recommended values, and the failure mode was between the copper ribbon and the pad, as recommended by the standard.

[0150] The foregoing detailed description has been provided by way of illustration and description and is not intended to limit the scope of the appended claims. Many variations of the presently preferred embodiments described herein will be apparent to those of ordinary skill in the art and remain within the scope of the appended claims and their equivalents.

Claims

1. 1. A method for manufacturing bond pads for connecting a die to a copper ribbon or copper wire, comprising: providing a sheet of copper foil having a first major surface opposite a second major surface; Providing a sinterable film of metal particles; laminating the sinterable film to the first major surface to form a laminate sheet; and stamping bond pads from said laminate sheet.

2. The method of claim 1 , wherein the copper foil comprises copper or a copper alloy and / or is a multi-layer structure.

3. The copper foil is a thickness of 10 to 200 μm, preferably 50 to 150 μm, and / or A hardness Hv of 50 to 100, and / or The method of claim 1 or 2, having a coefficient of thermal expansion (CTE) of 10 to 20 ppm.

4. The method according to any one of claims 1 to 3, wherein the copper foil is perforated.

5. The sinterable film comprises: silver particles having a longest dimension between 1 and 1000 nm; A method according to any one of claims 1 to 4, comprising:

6. The method of claim 5, wherein the sinterable film comprises 0.1 to 2 wt. % of the polymer binder, preferably 0.5 to 1 wt. % of the polymer binder, based on the total weight of the sinterable silver film.

7. The method according to claim 5 or 6, wherein the polymer binder comprises an amide polymer, preferably poly(N-vinylacetamide).

8. A method according to any one of claims 5 to 7, wherein the silver particles have a longest dimension of from 5 to 500 nm, preferably from 10 to 100 nm, more preferably from 30 to 60 nm.

9. The silver particles in the sinterable film are and / or a D90 of 1000 nm or less, preferably 500 nm or less, more preferably 100 nm or less, even more preferably 60 nm or less; and / or 9. The method of any one of claims 5 to 8, forming microparticles having a D10 of 1 nm or more, preferably 5 nm or more, more preferably 10 nm or more, even more preferably 30 nm or more.

10. 10. The method of any one of claims 1 to 9, wherein the sinterable film comprises 90 to 99 wt. % silver particles, preferably 92 to 98 wt. % silver particles, more preferably 94 to 96 wt. % silver particles, based on the total weight of the sinterable film.

11. The method of any one of claims 1 to 10, wherein the sinterable film comprises a halogenated alcohol activator having a melting point of 80 to 150°C.

12. 12. The method of claim 11, wherein the sinterable film comprises 0.05 to 1 wt. % of the halogenated alcohol activator, preferably 0.1 to 0.2 wt. % of the halogenated alcohol activator, based on the total weight of the sinterable film.

13. 13. The method according to claim 11 or 12, wherein the halogenated alcohol activator has a melting point of 85 to 140°C, preferably 90 to 130°C, more preferably 100 to 120°C.

14. The halogenated alcohol activator is at least 150, preferably at least 200, and / or 500 or less, preferably 400 or less, more preferably 300 or less, and / or The method according to any one of claims 11 to 13, wherein the polysaccharide has a molecular weight of from 150 to 500, preferably from 200 to 300.

15. The method of any one of claims 11 to 14, wherein the halogenated alcohol comprises a brominated alcohol.

16. 16. The method of any one of claims 11 to 15, wherein the halogenated alcohol comprises a dibrominated alcohol.

17. 17. The method of any one of claims 11 to 16, wherein the halogenated alcohol contains from 3 to 5 carbon atoms.

18. The method of any one of claims 11 to 17, wherein the halogenated alcohol comprises a monohydroxy alcohol.

19. The method of any one of claims 11 to 18, wherein the halogenated alcohol comprises 3,4 dibromo-2-butanol and / or 1,4 dibromobutan-2-ol.

20. Partially hydrogenated gum rosin, preferably in an amount of 0.1 to 0.3 wt. %, based on the total weight of the sinterable silver film; and / or The method according to any one of claims 11 to 19, further comprising finely divided wax, preferably in an amount of 0.2 to 0.4 wt. %, based on the total weight of the sinterable silver film.

21. laminating the first major surface with the sinterable film comprises: contacting the sinterable film with the first surface; and applying heat and pressure to the copper foil and the sheet of sinterable film.

22. 22. The method of claim 21, wherein the first surface comprises a metal plating layer, and contacting the sinterable film with the first surface comprises contacting the metal plating layer with the sinterable silver film.

23. 23. The method of claim 22, wherein the metal plating layer comprises silver, a nickel-gold alloy and / or ENIG (electroless nickel immersion gold).

24. The method according to any one of claims 21 to 23, wherein the metal plating layer has a thickness of 1 to 5 μm.

25. Applying heat and pressure to the copper foil and the sheet of sinterable film comprises: Applying a pressure of at least 0.5 MPa, preferably at least 0.8 MPa, more preferably 0.5-2 MPa, even more preferably 0.8-1.2 MPa, even more preferably about 1 MPa; and / or 25. A method according to any one of claims 21 to 24, comprising heating the sheet of copper foil and / or sinterable film to a temperature of 100 to 200°C, preferably 120 to 170°C, more preferably 140 to 160°C, even more preferably about 150°C, preferably for a period of 1 to 60 seconds, more preferably 2 to 40 seconds, even more preferably 5 to 15 seconds, even more preferably about 10 seconds.

26. 26. The method of any one of claims 1 to 25, further comprising applying an adhesive to the sinterable film on the laminate sheet, and wherein the die-cutting is performed such that an adhesive is present on the sinterable film on the bond pads.

27. The adhesive is A diphenyl compound preferably having a melting point of 50 to 90° C., and / or Triphenyl compounds, preferably having a melting point of 50 to 90° C., and / or 27. The method of claim 26, comprising a fatty alcohol, preferably having a melting point of 30-60°C.

28. 28. The method of claim 26 or 27, wherein the adhesive comprises a polyvinyl ether.

29. A bond pad produced according to the method of any one of claims 1-28.

30. A sinterable silver film comprising: silver particles having a longest dimension between 1 and 1000 nm; A polymer binder; and a halogenated alcohol activator having a melting point of 80-150°C.

31. 31. The sinterable silver film of claim 30, wherein the silver particles have a longest dimension of 5 to 500 nm, preferably 10 to 100 nm, more preferably 30 to 60 nm.

32. The silver particles in the sinterable silver film are and / or a D90 of 1000 nm or less, preferably 500 nm or less, more preferably 100 nm or less, even more preferably 60 nm or less; and / or 32. The sinterable silver film of claim 30 or 31, which forms a particulate having a D10 of 1 nm or more, preferably 5 nm or more, more preferably 10 nm or more, and even more preferably 30 nm or more.

33. 33. The sinterable silver film of any one of claims 30 to 32, comprising 90 to 99 wt. % silver metal particles, preferably 92 to 98 wt. % silver metal particles, and more preferably 94 to 96 wt. % silver metal particles, based on the total weight of the sinterable film.

34. 34. The sinterable silver film according to any one of claims 30 to 33, comprising 0.1 to 2 wt. % of said polymer binder, preferably 0.5 to 1 wt. % of said polymer binder, based on the total weight of the sinterable silver film.

35. The sinterable silver film of any one of claims 30 to 34, wherein the polymer binder comprises an amide polymer, preferably poly(N-vinylacetamide).

36. 36. The sinterable silver film of any one of claims 30 to 35, comprising 0.05 to 1 wt. % of a halogenated alcohol activator, preferably 0.1 to 0.2 wt. %, based on the total weight of the sinterable silver film.

37. The sinterable silver film of any one of claims 30 to 36, wherein the halogenated alcohol activator has a melting point of 85 to 140°C, preferably 90 to 130°C, more preferably 100 to 120°C.

38. The halogenated alcohol activator is at least 150, preferably at least 200, and / or 500 or less, preferably 400 or less, more preferably 300 or less, and / or 38. The sinterable silver film according to any one of claims 30 to 37, having a molecular weight which is between 150 and 500, preferably between 200 and 300.

39. The sinterable silver film of any one of claims 30 to 38, wherein the halogenated alcohol comprises a brominated alcohol.

40. 40. The sinterable film of claim 39, wherein the halogenated alcohol comprises a dibrominated alcohol.

41. The sinterable silver film of any one of claims 30 to 40, wherein the halogenated alcohol contains 3 to 5 carbon atoms.

42. The sinterable silver film of any one of claims 30 to 41, wherein the halogenated alcohol comprises a monohydroxy alcohol.

43. The sinterable silver film of any one of claims 30 to 42, wherein the halogenated alcohol comprises 3,4 dibromo-2-butanol and / or 1,4 dibromobutan-2-ol.

44. Partially hydrogenated gum rosin, preferably in an amount of 0.1 to 0.3 wt. %, based on the total weight of the sinterable silver film; and / or The sinterable silver film of any one of claims 30 to 43, further comprising finely divided wax, preferably in an amount of 0.2 to 0.4 wt. %, based on the total weight of the sinterable silver film.

45. Bond pads for connecting the die to copper wires or ribbons, Copper foil and A sinterable silver film according to any one of claims 30 to 44 laminated onto the copper foil; Optionally, a metal plating layer sandwiched between said copper foil and said sinterable silver film.

46. 46. ​​The bond pad of claim 45, wherein the copper foil comprises copper or a copper alloy and / or is a multi-layer structure.

47. A bond pad according to claim 45 or claim 46, wherein the copper foil has a thickness of 10 to 200 μm, preferably 50 to 150 μm.

48. The bond pad of any one of claims 45 to 47, wherein the copper foil has a hardness Hv of 50-100.

49. The bond pad of any one of claims 45 to 48, wherein the copper foil has a coefficient of thermal expansion (CTE) of 10 to 20 ppm.

50. The bond pad of any one of claims 45 to 49, wherein the copper foil is perforated.

51. The bond pad of any one of claims 45 to 50, wherein the metal plating layer comprises silver, nickel gold alloy and / or ENIG (electroless nickel immersion gold).

52. The bond pad of any one of claims 45 to 51, wherein the metal plating layer has a thickness of 1 to 5 μm.

53. The bond pad of any one of claims 45 to 52, further comprising an adhesive on an outer surface of the sinterable silver film.

54. The adhesive is A diphenyl compound preferably having a melting point of 50 to 90° C., and / or Triphenyl compounds, preferably having a melting point of 50 to 90° C., and / or 54. The bond pad of claim 53, comprising a fatty alcohol, preferably having a melting point of 30-60°C.

55. 55. The bond pad of claim 53 or 54, wherein the adhesive comprises a polyvinyl ether.

56. 1. A method for connecting a die to copper wires and / or copper ribbons, comprising: Providing a die; Providing a bond pad according to any one of claims 29 and 45 to 55; contacting the sinterable film of the bond pad with the die; heating the sinterable film to connect the bond pads to the die; and welding a copper wire and / or copper ribbon to the copper foil of the bond pad.

57. 57. The method of claim 56, wherein the welding comprises ultrasonic welding and / or laser welding.

58. 58. A method according to claim 56 or 57, wherein the heating is carried out at a temperature of from 200 to 300°C, preferably from 220 to 280°C, more preferably from 240 to 260°C.

59. 59. A method according to any one of claims 56 to 58, wherein the heating is carried out under a pressure of from 2 to 20 MPa, preferably from 5 to 15 MPa, more preferably from 8 to 12 MPa, even more preferably at about 10 MPa.

60. 60. A method according to any one of claims 56 to 59, wherein the heating is carried out for 10 to 180 seconds, preferably 30 to 120 seconds, more preferably 50 to 100 seconds, even more preferably 60 to 90 seconds.

61. 61. The method of any one of claims 56 to 60, wherein the die comprises a metallized surface, preferably comprising silver, gold and / or palladium, and contacting the sinterable film of the bond pad with the die comprises contacting the sinterable film of the bond pad with the metallized surface of the die.

62. Contacting the sinterable film of the bond pad with the die comprises: preheating the die to a temperature of 130-180°C; and contacting the pre-heated die with the sinterable film with a force of 50-150N, preferably 70-130N, more preferably 80-100N, even more preferably about 90N, and / or with a placement time of 100-2000ms, preferably 200-1000ms.

63. The die has an adhesive on its surface, contacting the sinterable film of the bond pad with the die includes contacting the sinterable film of the bond pad with the adhesive; 63. The method of any one of claims 56 to 62, wherein contacting the sinterable film of the bond pad with the die is performed using a pick and place tool that is preheated to 50-90°C.

64. A method of manufacturing an electronic device comprising connecting a die to copper wires and / or copper ribbons according to the method of any one of claims 56 to 63.

65. 65. An electronic device manufactured in accordance with claim 64.

66. 56. An electronic device comprising and / or manufactured using a bond pad according to any one of claims 29 and 45 to 55.

67. 67. The electronic device of claim 65 or 66, wherein the electronic device comprises a power device or module.

68. 68. The electronic device of any one of claims 65 to 67, further comprising a substrate connected to the die via a sintered silver film.

69. A method for manufacturing a bond pad according to any one of claims 45 to 55, comprising the steps of: Providing a copper foil; Providing a sinterable silver film according to any one of claims 30 to 44; contacting the copper foil with the sinterable silver film; applying heat and pressure to the copper foil and the sinterable silver film to laminate the sinterable silver film onto the copper foil to provide a laminated copper foil; and stamping bond pads from the laminated copper foil.

70. 70. The method of claim 69, wherein the sinterable silver film comprises a metal plating layer, and contacting the copper foil with the sinterable silver film comprises contacting the metal plating layer with the sinterable silver film.

71. Applying heat and pressure to the copper foil and the sinterable silver film comprises Applying a pressure of at least 0.5 MPa, preferably at least 0.8 MPa, more preferably 0.5-2 MPa, even more preferably 0.8-1.2 MPa, even more preferably about 1 MPa; and / or 71. A method according to claim 69 or 70, comprising heating the copper foil and / or sinterable silver film to a temperature of 100-200°C, preferably 120-170°C, more preferably 140-160°C, even more preferably about 150°C, preferably for a period of 1-60 seconds, more preferably 2-40 seconds, even more preferably 5-15 seconds, even more preferably about 10 seconds.

72. 1. A method of assembly comprising the steps of: providing a substrate having a die thereon, the substrate and die being separated by a sinterable film; Providing a bond pad according to any one of claims 29 and 45 to 55; contacting the bond pad to the die through the sinterable film of the bond pad; sintering the sinterable film; and Providing a copper ribbon or copper wire; and connecting said copper ribbon or copper wire to said die and optionally also to said substrate.

73. 73. The method of claim 72, wherein providing the bond pads includes providing the bond pads on a tape and reel assembly, and wherein contacting the bond pads with the die is performed using a pick and place machine.

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