MXPA98006829A - Interface structures for electronic devices - Google Patents

Abstract

An interface includes floating pad metallization (30 or 630) patterned over a dielectric interface layer with a first portion forming a central pad (26 or 626) and a second portion forming an extension (28 or 628) from the central pad extending into an interface via. Another interface includes a floating contact structure including electrically conductive material (214) coating a hole with at least some of the floating pad metallization forming an extension (216) from the hole. A conductive contact area interface includes at least one interface structure (22, 24, 26, 28, or 30) coupled between first and second contact areas (112 and 118) and including an electrical conductor having a partially open interior to form a compliant joint between the first and second contact areas.

Description

I NTERFACE STRUCTURES FOR ELECTRONIC DEVICES BACKGROUND OF THE I NVENC ION Sphere grid matrix (BGA) technology provides a high density of interconnections per unit area, but thermal expansion coefficient (CTEs) imbalances occur when BGA substrates of ceramics or polymers and Printed circuit boards are attached and generally cause weld fractures in the joints, especially as the size of the substrates and temperature ranges increases. In the techniques of column grid arrays (CGA) and other BGA techniques, a eutectic welder is applied to the printed circuit board and to multi-chip module array supports and the resulting board is soldered to a column or sphere. higher temperature welding that does not melt. Both BGA and CGA structures can be inflexible and vulnerable to damage. For various types of BGA and CGA, reliability increases are attempted by sub-filling the structures with polymer glues to reinforce the interfaces and reduce the effects of imbalances in the weld joints. However, polymer glues deteriorate the possibility of repair due to the difficulty of removing the glues after hardening. Additionally, these types of structures require two separate welding steps and are more expensive than conventional welding structures, in addition to requiring more vertical space due to the increased height of the joints. A conventional technique of microscopic sphere grid matrix interface technique for attaching a semiconductor circuit chip directly to a substrate is to use a series of weld bumps accumulated in the center of the chip to force the area over which stresses occur between differential coefficients of thermal expansion. In this mode, the chips have their supports reconfigured and welding micro-protuberances are applied to the reconfigured supports. In one embodiment, the sphere grid matrix processes are used by restricting the temperature range during device operation from 30 ° C to 70 ° C in an effort to avoid the effects of CTE stresses. In another sphere grid matrix technique, the area where the chip faces the printed circuit board or substrate is not used for direct interconnection. Instead, the metallization is routed from the chip to the adjacent support structures which then have spherical weld connections. This technique can create limitations of foot counts and size as well as parasitic electrical effects. BRIEF DESCRIPTION OF THE INVENTION It would be desirable to have a method for providing electrically highly deformable conductive interconnections for structures having different coefficients of thermal expansion and for having a base support and metallization contact area with long-term reliability (i.e. fractures or breaks) even under conditions of material and thermal stresses, without the need to re-route chip supports to the center of a chip or to an adjacent support structure. In one embodiment of the present invention, a method and structure electrically interconnect materials having different coefficients of thermal expansion. A "floating support" structure is used to increase reliability by providing thermal and stress adaptation of the two materials and allow movement of the floating support independently of the support base. The invention includes a floating support interface structure which is connected to an original interconducting chip support by micro-extensions which provide stress relief for different thermal expansion coefficients. Floating support interface structures include simple support and extension or several Extensions in situations where a single extension is not sufficient for extreme stress / thermal resistance situations. The present invention provides a structure that adapts thermal and material stresses without subjecting the track interconnection areas to forces that can fracture them or that can break connections in the chip supports. The floating supports allow the independent movement of a semiconductor while providing electrical interconnections through selected materials that have specific configurations to provide low forces in the areas of the track and thus adapt differential thermal stresses that can cause large differences in CTE. In another embodiment of the present invention, a micro interface structure is provided which is weldable and forms an electronic interconnection without requiring pressure. The interconnections can be held in position before application by an interposer that provides ease of assembly and self-alignment capability of surface mounting technology. A conductive contact area interface may comprise: at least a first electrically conductive contact area; at least a second electrically conductive contact area facing and substantially aligned with the at least one first contact area; and at least one interface structure coupled between the at least first contact area and the at least second contact area. The at least one interface structure comprises at least one electrical conductor having a partially open interior to form a deformable joint between the at least one first contact area and the at least one second contact area. It would be desirable to additionally have a more flexible interface structure for electronic devices that does not require an underlying base surface and that can be used to relieve stresses of structures such as multiple chip modules (MCMs), chips, chips or individual blanks, micro structures -electro-mechanical (MEMs), printed circuit boards and surface mounting technologies that can be produced from inequalities of thermal expansion coefficients with connections such as those formed by arrays of sphere grids, micro matrixes of spheres, arrays of column grids, flying micropads, welding joints, or automated ribbon union connections. In one embodiment of the present invention, a flexible film interface includes a flexible film; flexible material attached to a portion of the flexible film; surface metallization in the flexible material, the flexible film having at least one path extending therethrough to the metallization of the surface; and a floating support structure including floating support metallization configured on the flexible material and flexible metallization, a first portion of the metallization of the floating support forming a central support and a second portion of the metallization of the floating support forming at least one extension of the central support and extends to the at least one way. BRIEF DESCRIPTION OF THE DIAMETERS The aspects of the invention considered novel are set forth with particularity to the appended claims. However, the invention itself, both in terms of organization and method of operation, together with additional objects and advantages thereof, can best be understood by reference to the following description taken in conjunction with the accompanying drawings. , wherein the similar numerals represent similar components, in which: Figure 1 is a side view in section of a deformable covering that covers a base support. Figure 2 is a view similar to that of Figure 1, further including a first dielectric interface layer. Figure 3a is a view similar to that of Figure 2, further including floating support structures that cover the first interface dielectric layer. Figure 3b is a view similar to that of Figure 3a, further showing the removal of the first interface dielectric layer. Figure 4 is a plan view of one of the floating support structures configured on the base support. Figures 5a, 5b and 5c are plan views of other floating support modalities. Figure 6 is a sectional side view of another floating support mode. Figure 7 is a view similar to that of Figure 3a, further including a second dielectric interface layer and a second pair of floating support structures that cover the first interface dielectric layer. Figure 8 is a plan view of one of the second pair of floating support structures. Figure 9 is a view similar to that of Figure 7, further including a third dielectric interface layer having openings on the second floating support structures for placing a weld protrusion and a welding sphere, showing the excess dielectric material removed. Figure 10, is a view similar to that of Figure 3a, further showing a second interface dielectric layer having metallized tracks for joining a weld bead and weld bead. Figure 11 is a view similar to that of Figure 3a, further showing a second dielectric interface layer having tracks in which there is welding. Figure 12 is a view similar to that of Figure 11, further including a third interface dielectric layer having openings on the weld to place a weld protrusion and a weld ball. Figure 13 is a sectional side view of an interface structure for a floating leg contact. Figure 14 is a plan view of one of the legs of Figure 14. Figure 14a is a sectional side view of an interface structure where the orifices do not extend along an intermediate substrate. Figure 15 is a sectional side view of a printed circuit board and a multi-chip module, each having area array supports. Fig. 16 is a view similar to that of Fig. 1 5, further including several interface modalities of the present invention. Figure 17 is a view similar to that of Figure 16, further including an interposer mode of the present invention. Figure 18 is a schematic side view of the interface and the interposer. Figure 19 is a view similar to that of Figure 18, additionally including weldable surfaces in the interface. Figure 20 is a view similar to that of Figure 17, showing a curved base. Figure 21 is a sectional side view of a flexible film having flexible material with surface metallization attached to it. Figure 22 is a view similar to that of Figure 21, further including floating support structures covering the flexible film. Figure 23 is a plan view of one of the floating support structures configured to cover a portion of the surface metallization. Figure 24 is a view similar to that of Figure 22, further showing an optional welding mask extending over the flexible film. Figure 25 is a view similar to that of Figure 24, further showing the joining of the metallization of the surface to base supports through a welding sphere and an epoxy sphere. Figure 26 is a view similar to that of Figure 25, further showing the attachment of the floating support structures to conductive bearings through a sphere grid matrix. DETAILED DESCRIPTION OF THE INVENTION Figure 1 is a side sectional view of a deformable covering 14 covering a base surface 10, having conductive supports 12. The base surface may comprise a semiconductor chip that has not yet been cut in segmented individual chips or a chip that has been segmented from a chip. Processing on a chip that has not yet been segmented allows serial fabrication of interface structures and avoids problems of handling individual chips such as corner edge separations of the deformable coating and alignment difficulties associated with handling simple dies for photolithographic processing. The base surface may alternatively comprise, for example, a passive component, a printed circuit board (PC), a multi-chip module (MCM), a flexible interconnect layer structure, such as that described in the US Patent. United States No. 5,527,741, granted to Cole and co-inventors on June 18, 1996, or a substrate or chip including photonic structures, liquid crystal structures or micro-electro-mechanical structures (M EMS) such as those described for example, in the Patent of the United States of North America No. 5, 454,904, by Ghezzo and co-inventors, granted on October 3, 1995, assigned to the same owner of this invention. MEMS and photonic devices can be integrated directly into chip processing steps to create a separate structure that can be added later to the chip. The conductive supports 12 may comprise supports or metallization on any of the above-mentioned base surfaces. With the present invention, the interface connections for conductive bearings are more stable, so that the conductive bearings can have smaller areas (such as a diameter or length range from 0.0254 mm to about 0.1016 mm) than conventional supports. The deformable coating 14 comprises a material such as poly-imide epoxide or siloxane polyimide (SPI / epoxide) described by Gorczyca and co-inventors in U.S. Patent No. 5, 161, 093, issued on November 3, 1992. The deformable coating may comprise a high or low modulus insulating material and commonly has a thickness ranging from about two microns to about 100 microns. The deformable coating can be laminated to the base surface 10 with heat and / or an adhesive (not shown) or deposited on the base surface by means of a chemical steam upsetting, deworning or deposition (CVD) technique, for example. The coating tracks 16 are formed in the deformable coating 14 by any suitable method. In one embodiment, as described in U.S. Patent No. 4,894,115, to Eichelberger and co-inventors granted on January 16, 1990, the deformable coating can be repeatedly scanned with a high-resolution continuous wave laser. energy to create track holes of the desired size and shape. Other suitable methods include, for example, photoconfigurable photo-configurable polyimides and use an "excimer" laser with a mask (not shown). The base metallization 18 can be formed by electronic deposition and / or electrolytic coating, for example, and be configured with a standard etching and photoresist process. U.S. Patent No. 4,835,704, issued to Eichelberger and co-inventors on May 30, 1989, describes a useful adaptive lithography system for, for example, configuring metallization. The base metallization in one embodiment comprises a thin layer of 1000 μm pulverized titanium adhesion, coated with a thin layer of powdered copper 3000 A, covered by a copper coating of galvanic coating at a thickness of four microns, for example. You can apply an optional buffer layer of 1000? of titanium on the copper of galvanic coating. Other examples of base metallization materials include molybdenum, tungsten and gold. The appropriate material of the base metallization will vary depending on the material on the base surface and the environment, such as a high temperature environment or an oxidizing environment, in which the electronic device will be used. Figure 2 is a view similar to that of Figure 1, further including a first interface dielectric layer 20, which preferably comprises a low coefficient flexible material, such as SPI / epoxide, other flexible epoxies, rubber materials of silicone, TEFLON® polytetrafluoroethylene (TEFLON is a registered trademark of El Pont de Nemours and Co.) or other polymers that have a low modulus or that have been modified to obtain a reduced modulus, with a thickness that is approximately two micrometers to approximately 0.0762 mm. A range of thickness is from about 100 microns to about 400 microns. The first interface dielectric layer 20 has tracks 22 therein extending to portions of the base metallization 10, overlaying the deformable coating 14. The tracks 22 of Figure 2 can be formed in a manner similar to the tracks 16. of Figure 1. If the first interface dielectric layer has a thickness less than that of the deformable coating, tracks 22 can be made smaller than tracks 16, as shown. Figure 3a is a view similar to that of Figure 2, additionally including floating support structures 30 and 30a covering the first interface dielectric layer 20, and Figure 4 is a plan view of one of the structures of floating support 30, covering on the base support. Floating support structures adapt material and thermal stresses without putting undesirable forces in the base metallization areas. The metallization for the floating support structures 30 can be applied and configured by techniques similar to those discussed with respect to the base metallization 18 of Figure 1. In Figure 4, the floating support structures include a central support 26, which has shaped extensions 20, which extend through the metallization of track 24 to the base metallization 18. The size of the central supports 26, will vary from according to the specific planned use of the floating support structure. For example, if a welding sphere or welding protrusion is attached directly to the central support, it must be large enough to adapt the joint. The size of the central support will also affect the length of the extensions. The smaller diameter center supports require less space than the larger diameter supports and therefore allow more space for longer extensions. The base metallization area 18 is an additional factor that can affect the available length of extensions. The metallization thickness for the floating support structures may be uniform, as shown by the floating support structure 30, or variable, as shown by the floating support structure 30a. A modified central support 26a in Figure 3a includes the central support 26 and an additional metallization area 27. In one embodiment, the extensions 28 have a thickness ranging from about 2 microns to about 8 microns, and the modified central support 26a, it has a thickness ranging from about 4 microns to about 20 microns. This embodiment is useful because the thin extensions are more flexible than the thicker extensions where the central support is preferably thick enough to be welded to another electrically conductive surface. In one embodiment, the additional metallization area comprises a metal that can be easily welded, such as a nickel-gold plate, for example. Figure 3b is a view similar to that of Figure 3a, further showing the removal of the first interface dielectric layer. For example, in some embodiments such as MEMS, removal of the first interface dielectric layer 20 is desirable so that the first interface dielectric layer does not impede the movement of the MEMS devices or interfere with the optical devices. The removal of the first interface dielectric layer is also useful because it provides opportunities to fabricate structures that have movement, which can be used for control or measurement purposes. In these embodiments, the material of the first interface dielectric layer 20 is selected to be a material that can be removed by a sublimation process, a solvent or a laser without interfering with the deformable coating 14.

In a related embodiment, at least a portion of each area 20a, under a respective floating support structure of Figure 3a, can be removed leaving the remainder of the interface dielectric layer 20 in place. If desired, the first interface dielectric layer can comprise a photosensitive material that is sensitized in regions other than the support regions and can then be easily removed from below the floating support interfaces. This embodiment provides an ability to insert a specific filling material for the application (which may be a solid or a fluid) under the floating support interface in the areas 20a, to provide a special thermal or damping (vibration) control. Figures 5a, 5b and 5c are plan views of other floating support modalities. The metallization configuration of the floating support structure shown in Figure 4 is presented only for exemplification purposes. Any number of extensions (one or more) can be used and the extensions do not have to be straight. As shown in Figure 5a, the serpentine-shaped extension 28a, the spiral extension 28b, the sawtooth-shaped extension 28c, and the folded extension 28a, represent potential shapes for exemplification purposes. As shown in Figure 5b, the central support 526 may be surrounded by the extensions 528, which extend to a ring 530, which in turn may have additional extensions 532 extending to another ring 534, which has tracks 536, which extend to base metalization 18 (not shown in Figure 5b). As shown in Figure 5c, the extensions 28 can be curved to form a floating interface support in the form of a peak wheel. The shapes of Figures 5a, 5b, and 5c may be useful for reducing the mechanical stress on the extensions and are especially useful if the base surface 10 is not planar. When selecting an extension form, any resulting inductance effect must be considered. Figure 6 is a sectional side view of another floating support mode that may be useful to reduce the mechanical stress in the extensions. In Figure 6, the first interface dielectric layer 20, has a recessed portion 20a, which can be formed during the application of the first dielectric interface layer, can be etched from the first interface dielectric layer in a separate step, or It can be punched by heat to give it the shape. When the metallization is applied to the floating support interface structure 30b, the extensions 28 will have recesses for stress relief. The metallization area 27a can be applied, so that the metallization of the central support is similar or superior to the level of the extensions. Although not shown, it is expected that the embodiments of Figures 3a and 3b have some natural recesses resulting from the application of the metallization of the floating support structures. Figure 7 is a view similar to that of Figure 3a, further including a second interface dielectric layer 32, and a second pair of floating support structures 33 covering the first interface dielectric layer 20, and Figure 8, is a plan view of one of the second pair of floating support structures 33. In this embodiment, each of the first pair of floating support structures is modeled to have some extensions 28, coupled through the tracks 24 to the layer base metallization 18, and other extensions 28a, which are not coupled to the base metallization layer. The second interface dielectric layer 32 may comprise a material similar to that of the first interface dielectric layer 20, which is configured to include the tracks 36, which extend to the extensions 28a, which are not directly coupled to the interface layer. base metallization. Likewise, the second floating support structure 33 can be manufactured with central supports 38 and extensions 40., in a manner similar to the first pair of floating support structures 30. Although for purposes of simplicity, Figure 3a illustrates a single layer floating interface mode and Figure 7 illustrates a double layer floating interface mode, can be add additional layers of floating interface structures. Said additional layers are useful for providing greater stress adaptation when a single or double layer of floating support is not sufficient for extreme cases of stress or thermal deformation. The multi-layered interface modalities create additional thermal-mechanical insulation because the floating support structures are further apart and provide a compound lever and thus, more degrees of physical freedom. Figure 9 is a view similar to that of Figure 7, additionally including a third interface dielectric layer 42, having openings on the second floating support structures for placing a weld protrusion 44 and a welding sphere 48, in flux 46 and showing the excess dielectric material removed in an area 45. The removal of excess dielectric material helps to eliminate the accumulation of stress on the surface area (which can cause warpage or distortion) and provides greater flexibility and deformation . The dielectric material can be removed by any number of techniques such as photoresist and etching step, mechanical milling or laser ablation, for example. Figure 10 is a view similar to that of Figure 3a, further showing a second interface dielectric layer 32, having metallized tracks 50, for attaching a weld protrusion 44 and welding sphere 48. Metallization 50, it can apply in a similar manner to the metallization 18. In one embodiment, the metallization 50 comprises a nickel-gold alloy which creates an improved contact for soldering. The application of the interface dielectric layer 32 and the metallization 50 can be an alternative to using the metallization area 27 (shown in FIG. 3a) to increase the thickness of the contact area of the central support. Figure 11 is a view similar to that of Figure 3a, further showing a second interface dielectric layer 32 having tracks in which there is welding. The welding can be applied by techniques such as metal scanning, heat reflux, crackling or electroplating, for example. In the embodiment of Figure 11, the second interface dielectric layer 32 may comprise a material such as a polyimide or a solder mask. Figure 12 is a view similar to that of Figure 11, additionally including a third interface dielectric layer 56, having openings on the weld for placing a weld protrusion 44 and a weld sphere 48. The third dielectric layer Interface 56 may comprise a material such as a poly-imide or a solder mask and is useful for maintaining the weld 54 during the joining of the sphere or weld protrusion. If desired, the first, second or third dielectric layers of interface 20, 32 and 56 can be completely removed, as discussed with respect to the first interface dielectric layer 20 of Figure 3b or at selected locations (together with the deformable coating 14, if desired) as discussed with respect to Figure ?. With the present invention, MEMS, photonic devices, liquid crystal structures and semiconductor chips such as silicon carbide chips, silicone and gallium arsenide, for example, can be welded directly to various substrate materials such as ceramics, polymers and Flexible interconnection layers, for example, with broad reliability over a wide temperature range. Additionally, repairs can be made by heating and melting the weld without having the conventional step of reconfiguring chip supports to a central location. Figure 13, is a sectional side view of an interface structure for a floating leg contact, such as that which may be present in a leg rejector array (PGA) device and Figure 14, is a plan view of one of the legs of Figure 14. The rigid leg connection structures of coupling to printed circuit boards can create mechanical stresses during manufacturing and operation similar to the stresses created when joining semiconductor chip supports to a substrate. Microprocessor chips can create high temperatures, which create large CTE differentials between the chips and the printed circuit boards on which they are attached. In Figures 13 and 14, a substrate 210 may comprise a printed circuit board, a flexible interconnect layer, or any other structurally appropriate material. The low modulus interface dielectric regions 212 may comprise materials similar to those discussed with respect to the first interface dielectric layer 20 of Figure 2. The interface dielectric regions 212 may be coated with metallization 214 which covers holes in the interface dielectric regions and has extensions 216, extending therefrom on each surface of the substrate 210. Preferably, the metallization is configured to form extensions extending to a support interconnect region 21 1, which is coupled by metallization tracks to other support interconnect regions or metallization areas (not shown) of the substrate. The weld 222 can be applied between the metallization and an electrically conductive leg 220, which is attached to a support structure 218. "Flotation" through orifice structures occurs because the electrical interfaces and the extensions. allow the substrate to adjust to mechanical stresses for different coefficients of thermal expansion and mechanical stresses encountered when inserting and removing matrices of leg rej ects and other devices with legs. Although the holes are shown in Figure 13 as extending through the interface dielectric regions, the invention is also useful in situations where the orifices extend only part of the path through the dielectric material of the interface. Figure 14a is a sectional side view of an interface structure in which the orifices do not extend along an intermediate substrate 21a. Figure 14a also illustrates an embodiment wherein the entire substrate comprises a low modulus dielectric region. The substrate in Fig. 1a 4a. it is useful as a coupling board between a printed circuit board 240 and a chip having legs, for example. The intermediate substrate 210a, has intermediate supports 242, which can be coupled by internal metallization to supports or other metallization on an opposite surface (not shown) of the intermediate substrate and can be coupled by welding 246, to supports 244 of a circuit board printed 240, for example. Figure 15 is a sectional side view of a printed circuit board (PC) 110, having first contact areas represented by matrix supports 1 12, which are covered with welding 1 14, and a second surface represented by a multiple chip module (MCM) 1 16, having second contact areas, represented by matrix supports 1 18, which are covered with solder 120, and are substantially aligned with the respective supports of matrices 1 12. Although they are shown Matrix supports on a printed circuit board and MCM, the present invention is useful for coupling any number of metal areas. Other types of metal contact areas where the present invention may be useful include, for example, metallization tracks on substrates, metallized substrates, flexible interconnecting structures, circuit chip supports, semiconductive chip chip supports, infrared sensors and holographic matrices. In a surface such that the printed circuit board 1 10 is a heat sink, includes a heat sink, or is attached to a heat sink 1 13 by means of an adhesive 1 1 1 (as shown in Figure 15) the structures of Interface can create a thermal path that can be used to remove heat from an MCM. Figure 16 is a view similar to that of Figure 15, further including various interface structures of the present invention. Each of the interface structures has a partially open interior to form a deformable joint between the contact areas it engages. "Partially open interior" means an interior that includes air (open spaces) or a deformable material in addition to the material that is used to electrically couple the contact areas. An interface structure of this type is represented by a set of crushed wire 122, which is manufactured by pressing very thin metal wires in a structure having a structure similar to that of wool of fibers containing mineral substances and which intrinsically has a spring action in several planes. Said wire set interface structures are available from Cinch Connector Devices, of Elk Grove Village, I L, under the registered trademark of FUZZ buttons. The wire tracks are less inducible than the BGA and CGA, so that the size of the power actuators of the electronic devices can be reduced. The wire assembly 122 may comprise materials such as copper, gold, beryllium copper, beryllium copper with gold plate and alloys of precious metals such as palladium gold alloys. Commonly, the thickness of the wires ranges from about 0.0127 mm to about 0.508 mm. A single compressed wire or a plurality of compressed wires can be used for a crushed wire assembly. For standard die supports ranging from 0.0762 mm to approximately 0.1778 mm, a diameter of wire assembly 122 would be approximately 0.0762 mm. The wire assembly 122 may have any shape that allows two areas of metal to be coupled. For example, round, cylindrical, hourglass and rectangular shapes are also appropriate for the wire assembly. Another interface structure is represented by a braided core wire assembly 124, which includes braided vertical wires surrounded by insulation. In one embodiment, the wires comprise insulated wires of fine copper. The insulation must be a material that can withstand the temperatures at which the welding will take place. An example material is TEFLON® polytetrafluoroethylene. The wires may be wrapped with insulation and inserted between the two metal areas. If the wires are not exposed at the ends of the interface, a process of solvent retraction, mechanical polishing or etching can be used to expose them. Due to the insulation, the weld will not wick appreciably in the braided core wire assemblies. Another interface structure is represented by a braided core wire assembly 126, having removable insulation comprising a material such as a dissolvable polymer or a wire varnish. The use of sublimable insulation is analogous to the insulating varnish for transformers that can be removed by sublimation or solvents, for example, after finishing the welding. As discussed above, when the isolation of the vertical wires is removed, an improved flexible structure is created. Another interface structure is represented by a crushed wire assembly 128, having capped ends 129. The crushed wire may have an irregular surface that can be leveled by lids comprising welding or a metal to facilitate welding of the interface to the contact areas. The crushed wire assemblies may also include removable insulation or welding resistance if desired to further inhibit the formation of weld wicks in the crushed wires. Such formation of welding wicks would reduce the flexibility of the interfaces. Another interface structure is represented by a deformable column 130. Column 130, comprises an outer layer of metallization 131, which surrounds an internal area which may comprise a flexible material, an example of which is a polymer such as rubber, or a hollow area. In order to provide a hollow internal area 133, the material may be initially present during manufacture and then removed by a process such as sublimation or diffusion. In this embodiment, one or more openings (not shown) would be needed in the outer layer of the metallization to facilitate the removal of internal material. Figure 17 is a view similar to that of Figure 16, further including an optional interposing mode 132. The interposer is useful for holding the interface structures in position during welding. The interposer can be left in position after welding or it can be removed. If the structure of the interposer is to be removed, a material such as wax or a polycarbonate which dissolves or decomposes in a solvent can be used. If the structure of the interposer will remain, any structurally appropriate material that can withstand the operating and manufacturing temperatures of the assembly can be used. Examples include printed circuit boards and hard or pressure-filled plastics such as polyphenylene sulfide. Figure 18 is a schematic side view of interface structures 134 and the structure of interposer 132. In one embodiment, rivet forms of the interface structures are produced so that portions of the interface structures extend over the structure of the interface. interposing to prevent the interface structures from leaving the interposer structure. The rivet forms can be produced in any conventional manner such as press molding, for example. A non-press fit rivet 134a, which can be moved horizontally and / or vertically, can be useful to reduce the stress on the structure of the interposer and the contact areas during high temperature operations, providing flexibility for welding in order to move interfaces in alignment with contact supports, and providing flexibility for curved surfaces. In one embodiment to create an adjustment without pressure, the structure of the interposer is immersed in a material that can be dissolved in a solvent, the interface structures are inserted into the structure of the interposer, the rivets are created, and the structure of the interposer is Immerse in a solvent to remove the immersion material. As discussed with respect to the interface structures 126 and 1 28 of Figure 16, the interface structures can be modified by filling them with an insulating substance which prevents the formation of weld wicks in the vertical or crushed braided wires. . If the weld forms wicks with sufficient depth at the interfaces, a solid inflexible structure can be produced and would not provide an effective adaptation of the thermal stress of CTE. The insulating material can be added by a method such as immersion and comprise a polymer that can be dissolved in an appropriate solvent or any variety of organic or inorganic materials that can be removed by any number of techniques. . A technique of its heat blinding is described in the Patent of the United States of North America No. 5, 449, 427 of Wojnarowski and co-inventors, granted on September 12, 1995, for example. After assembly, the insulating material can be removed, if desired, by any number of techniques such as sublimation, solvents, thermal decomposition and the like to increase the spring-like deformation of the interface structures. Figure 19 is a view similar to that of Figure 18, further including weldable surfaces 138 on the interface. The upper and lower areas can be chemically treated or mechanically polished to reveal a weldable surface. For example, you can use plasmas, RÍE (active engraving), solvents, flame treatments or mechanical polishing to expose the desired areas of the rivet buttons. An optional step of pre-tinning an interface structure surface by submerging it in welding or metallizing it by metallization produced by chemical reduction, can facilitate the welding of the interfacing surface to the contact area and help the surface tension of the weld to align the interfaces with the contact supports. Repair can be achieved by heating the interfaces and melting the weld. If there is no insulating material (either there has never been one or the material has been removed), the weld forms weld joints and towards the interface structures and thus the excess weld is removed from the area repair without requiring manual reprocessing.

The present invention can be used as a flattening technique for assembling non-planar parts. This is useful because surfaces such as printed circuit boards are not always flat and because the surfaces they connect to may be curved, for example. Figure 20 is a view similar to that of Figure 17, showing a curved base 310, with supports 312, coupled to the supports 318 of the surface 316 by interfaces 334, adjusted without pressure in an interposer 332. Figure 21, is a sectional side view of a flexible film 610, which is bonded to the same flexible material 612 and 614 with surface metallization 616. The flexible film 610 flexibly comprises a flexible polymer such as, for example, KAPTON polyimide ® (KAPTON is a registered trademark of DuPont Co.) In one embodiment, the flexible film has a thickness ranging from about 7.5 micrometers to about 125 micrometers. The flexible material 612 and 614, preferably comprises a flexible low modulus material, such as SPI / epoxide, other flexible epoxies, silicone rubber materials, heat set epoxy MU LTI POSIT® XP-9500 (MU LTI POS IT is a trademark of Shipley Company Inc., Marlborough, MA), TEFLON® polytetrafluoroethylene (TEFLON is a registered trademark of DuPont), porous polytetrafluoroethylene, or other polymers that have a low modulus or that have been modified to obtain a reduced modulus, having a thickness ranging from approximately 0.5 millimeters to approximately 1,250 millimeters, depending on the application and the net differential stress that will be adapted. The flexible material provides a flexible soft interface to allow a floating support applied afterwards to move easily as CTE imbalances adapt. The flexible material can be applied by upset coating, spray coating, film photodeposition or roll coating, for example. The material can be configured by photoconfiguration and / or masking techniques, for example. As shown in Figure 21, the flexible material may have a uniform thickness (as shown by the flexible material 612) or a variable thickness (as shown by the flexible material 614). The tapered edges of flexible material 614 may be useful to reduce the stress in the surface metallization 616. The surface metallization 616 may be formed by sputtering and / or electroplating, for example, either through a mask or over the entire the surface followed by configuration with a standard etching and photoresist process. For example, U.S. Patent No. 4, 835, 704, Eichelberger and co-inventors, issued May 30, 1989, describes a useful lithography system adapted to configure metallization. The surface metallization in one embodiment comprises a thin layer of adhesion from about 1000 A to about 2000 A of pulverized titanium, coated with a thin layer of pulverized copper from 3000 A to about 5000 A, coated by a copper layer of galvanic coating. at a thickness of about three microns to about ten microns, for example. The appropriate material of the surface metallization will vary depending on the material expected to be contacted and the environment, such as high temperature environment or an oxidizing environment for example, in which the electronic device will be used. If the surface metallization will be in contact with welding, preferably nickel and gold (with a thickness of about 1000 Á to about 2000 Á) are applied onto the copper with galvanic coating. If the surface metallization will be in contact with a conductive polymer, the titanium (with a thickness of approximately 1000 A to approximately 2000 A) is a useful material to be applied to copper. Figure 22, is a view similar to that of Figure 21, further including floating support structures 630, covering the flexible film 610, to form a flexible interface structure 601. The tracks 624 are formed of flexible film 610, and extend to the surface metallization 616, by any appropriate method. In one embodiment, as described in U.S. Patent No. 4,894, 115, to Eichelberger and co-inventors, issued on January 16, 1990, the flexible film can be repeatedly scanned with a high-resolution continuous wave laser. energy to create track holes of the desired size and shape. Other suitable methods include, for example, photoconfigurable photo-configurable polyimides and use an "excimer" laser with a mask (not shown). In a preferred embodiment, as shown in Figure 22, the surface metallization 616 has a portion 620, which covers the flexible material and another portion 621 that extends to contact flexible film 610. In this embodiment, it is useful to have tracks 624, which extend to contact portion 621 of the surface metallization. Although this embodiment is preferred, the present invention can be practiced if the tracks extend to portions of the surface metallization that are in contact with the flexible material. Figure 23 is a plan view of one of the configured floating support structures 630, covering a portion 620, of the surface metallization 616. The metallization for floating support structures 630 can be applied and configured by similar techniques to those discussed with respect to the surface metallization 616 of Figure 21. In Figures 22 and 23, the floating support structures include a central support 626, which has shaped extensions 628 that extend through the tracks 624 to the surface metallization 616. The size of the central supports 626, will vary in accordance to the planned specific use of the floating support structure. . For example, if a welding sphere or welding protrusion is attached directly to the central support, it must be large enough to adapt the joint. As discussed with respect to Figure 3a, the metallization thickness for the floating support structures may be uniform or variable (the central panel being thicker than the extensions). In one embodiment, the extensions 628 have a thickness ranging from about 2 microns to about 8 microns, and the central support 626 has a thickness ranging from about 2 microns to about 20 microns. This embodiment is useful because the thin extensions are more flexible than the thicker extensions where the central support is preferably thick enough to be welded to another electrically conductive surface. As discussed above, any number of extensions (one or more) can be used and the extensions can have any form. Examples include straight extensions, serpentine extensions, spiral extensions, sawtooth-shaped extensions, and bent extensions, bead-shaped extensions, and extensions extending to a ring which in turn may have extensions. additional that extend to another ring (not shown). As discussed further with respect to FIG. 6, an indentation can be formed in the flexible film to reduce the mechanical stress in the extensions. The recess can be formed before, during or after the application of the flexible material by etching or heat cutting, for example. If a recess is formed in the flexible film, then the extensions 628 will have recesses for stress relief. Additional metallization can be applied to the central support if desired. Although not shown, it is expected that the modalities of Figures 22 and 24-26 have some natural recesses resulting from the application of the metallization of the floating support structures., even if the recesses were not formed intentionally. Figure 24 is a view similar to that of Figure 22, further showing an optional welding mask 632, which extends over the flexible film. This mask is useful if the central support 626 is to be welded to another conductive surface or support to prevent filtering or welding run over the extensions 628. The welding mask can comprise any material that is capable of masking welding. Examples include photo-configurable epoxides that can be exposed to ultraviolet rays and cured by heat. Figure 25 is a view similar to that of Figure 24, further showing the joining of the surface metallization 616 to base supports 712 through a conductive material 716. The conductive material may comprise a solder sphere or a polymer conductive, for example. A base member 710, underlying the base supports 712, may comprise a semiconductor chip that has not yet been segmented into segmented individual chips, a chip that has been segmented from a chip, a passive component, a printed circuit board (PC ), a multi-chip module (MCM), a flexible interconnect layer structure, such as that described in United States Patent No. 5,527,741, issued to Cole and co-inventors on June 18, 1996, or a substrate or chip which may include photonic structures, liquid crystal structures or micro-electro-mechanical structures (MEMS) such as those described for example, in U.S. Pat. No. 5,454,904, Ghezzo and co-inventors, granted on October 3, 1995, assigned to the same owner of this invention. The base supports 712, may comprise supports or metallization on any of the above-mentioned base members. The flexible interface structure can be manufactured separately from the base member and then joined by welding or by a conductive polymer such as a silver or gold epoxide, for example. If welding is used, a solder mask 714 can be applied on the base member. If the base member comprises an MCM, a high temperature lead solder (such as 10 parts tin and 90 parts lead) can be used. If the base member comprises a printed circuit board, a lower temperature solder (such as 37 parts tin and 63 parts lead) can be used. Figure 26 is a view similar to that of Figure 25, further showing the attachment of the floating support structures 630 to mounting supports 740 through a ball grid matrix 736 of a mounting member 742. BGA 736 welding spheres can be applied and the weld can be reflowed to the floating support structure. The mounting member may comprise structures and devices similar to those of the base member. Examples of particularly useful mounting members include flying micropads, surface mounting devices, ceramic filters, resistor assemblies, ceramic capacitors, MEMS and large processor dies that are fitted with welding support structures (micro BGA). If desired, the surface metallization 616 of the flexible interface structure can be configured for micro BGA output conductors to a full-size BGA for mechanical or placement reasons. Many devices can be simultaneously joined to the base member 710, using this device. Additionally, Figure 26 illustrates the removal of at least a portion of flexible film 610 and at least a portion of flexible material 612 and 614. If the flexible material is to be removed and if (as preferred) the surface metallization 616, surrounds the flexible material, at least a portion 728 of the flexible film (as well as any other coating welding mask)., if applicable) will have to be removed from the surface adjacent to the flexible material before the removal of any flexible material. Preferably, no portion of the flexible film is removed from the areas under the central support or extensions. In this embodiment, the material of the flexible film is preferably selected to be a material that can be removed by laser ablation or polymer calcination, for example, and the material of the flexible material is selected to be a material that is can be removed by a sublimation process or a solvent, for example, without interfering with the other materials to leave openings 750. Said partial removal of the flexible film and / or total or partial removal of the flexible material allows to increase the freedom of movement. If desired, multiple levels of floating supports (not shown) can be used. Said additional layers are useful to provide greater stress adaptation when a single floating support layer is not sufficient for extreme cases of stress or thermal resistance. The multi-layered interface modalities create additional thermal-mechanical insulation because the floating support structures are further apart and provide a compound lever and thus, more degrees of physical freedom.

Claims (10)

1. CLAIMS 1. An interface comprising: a base surface (10) having an electrically conductive base support (12); a deformable covering (14) on the base surface and the base support, the deformable coating having a coating path (16) extending through the base support; base metallization (18) configured on the deformable coating and extending in the coating path; a low modulus dielectric interface layer (20) covering the deformable coating and having at least one dielectric interface path (22) extending through the base metallization; and a floating support structure (30) comprising floating support metallization configured on the dielectric interface layer, a first portion of the floating support metallization forming a central support (26) and a second portion of the support metallization floating (28) forming at least one extension from the central support and extending towards the at least one dielectric interface.
2. 2. The interface of claim 1, wherein the floating support metallization includes at least two extensions (28) from the central support (26) and wherein the dielectric interface layer has at least two dielectric interface paths. (22) In the same, each extension extends to the respective path of dielectric interface.
3. 3. The interface of claim 2, wherein, above the base support, the levels of the dielectric interface layer and the floating support metallization recess.
4. The interface of claim 2, wherein the floating support metallization further includes at least two non-engaging extensions that do not extend in dielectric interface pathways; and further including an additional dielectric interface layer (32) covering the floating support structure and having additional pathways extending through the at least two non-engaging extensions; and an additional floating support structure (33) comprising additional floating support metallization configured on the additional dielectric interface layer, a first portion of the additional floating support metallization forming an additional central support (38) and a second portion of the additional floating support metallization forming additional extensions (40) of the central support and extending into the respective additional tracks.
5. 5. An interface comprising: a substrate (210) including a low modulus dielectric interface material (212) having at least one hole that extends partially through it; and a floating contact structure comprising electrically conductive material (214) covering the at least one orifice, at least part of the floating support metallization forming at least one extension (216) from the at least one a hole. The interface of claim 5, further comprising: an electrically conductive leg (220) connected to a support structure (21 8) and located in the at least one hole, and welding (222) coupling the electrically conductive leg and the floating contact structure. The interface of claim 6, wherein the substrate (21 0) additionally includes a rigid material surrounding the low modulus dielectric material. The interface of claim 5, wherein the at least one hole extends partially through the stratum, and wherein the substrate additionally comprises metallizing the substrate support (242) located on an opposite surface of the substrate. at least one hole and further comprising: an electrically conductive leg (220) with ecta gives a support structure (21 8) and located in the at least one hole; welding (222) coupling the electrically conductive leg and the floating contact structure; a surface (240) having a surface metallization support (244) in the same; and welding (246) by coupling the substrate support, the metallization support and the surface metallization support. 9. A conductive contact area interface comprising: at least a first electrically conductive contact area (1 12); at least a second electrically conductive contact area (1 18), the at least one second contact area being in front and substantially aligned with the at least first contact area; at least one interface structure (122, 124, 126, 128 or 130) coupled between the at least one first contact area and the at least one second contact area, the at least one interface structure comprising at least one electrical conductor having a partially open interior to form a deformable joint between the at least one first contact area and the at least one second contact area. 10. The interface of claim 9, further including first and second surfaces (1 10 and 16) and wherein the at least one first contact area comprises a first matrix of first electrically conductive contact areas (12). located on the first surface; the at least second contact area comprises a second matrix of first electrically conductive contact areas (1 18) located on the second surface, second contact areas being selected from the front and substantially aligned with first selected contact areas; and the at least one interface structure comprises a plurality of interface structures (122, 124, 126, 128 and / or 130), each interface structure coupled to a substantially aligned pair of first and second contact areas. The interface of claim 10, wherein the interface structures are coupled to the substantially aligned pair of first and second contact areas by solder joints (1 14 and 120); and wherein the plurality of interface structures comprises metal mesh structures (122 or 128), structures (124 and 126) including braided vertical wires or structures (130) each including an electrically conductive outer layer (131) surrounding an inner layer not conductive (133). The interface of claim 10, wherein an interposer structure (132) is present between the first and second surfaces and surrounds the interface structures. A method for manufacturing a conductive contact area interface structure between a first matrix of first electrically conductive contact areas (12) located on a first surface (1 10) and a second matrix of second electrically conductive contact areas (1 18) located on a second surface (1 16), the method comprising the steps of: substantially aligning second contact areas selected with first contact areas selected; placing an interposer (1 32) around a plurality of interface structures (122, 124, 126, 128 and / or 130) and between the first and second surfaces so that the interface structures are located between the respective substantially aligned pairs first and second contact areas, each interface structure comprising at least one electrical conductor having a partially open interior to form a deformable joint between a respective substantially aligned pair of first and second contact areas; and coupling the interface structures to the respective substantially aligned pairs of first and second contact areas with a weld ions (1 14 and 120). 14. The method of claim 13, wherein the step of placing the interposer around the interface structures includes forming the interface structures to form rivets (1 34) in holes in the material of the interposer. 5. The method of claim 14, wherein the step of shaping the interface structures, includes forming rivets without pressure adjustment (134a). 16. A flexible film interface (601) comprising: a flexible film (61 0); flexible material (61 2 or 61 4) attached to a portion of the flexible film; surface metallization (616) in the flexible material; the flexible film having at least one path (624) extending through the surface metallization; a floating support structure (630) comprising floating support metallization configured on the flexible material and the surface metallization, a first portion of the floating support metallization forming a central support (626) and a second portion of the floating support metallization forming at least one extension (628) from the central support and extending in the at least one way. The interface of claim 16, wherein the floating support metallization includes at least two extensions from the central support and wherein the flexible film has at least two paths therein, each extension extending to a respective way. The interface of claim 1, wherein the film portions (621) of the metallization of its surface are in contact with the flexible film and wherein the at least two paths extend to the portions of films of surface metallization. 9. An electronic package (602) comprising: (a) a flexible film interface (601) including: a flexible film (61 0); flexible material (612 or 61 4) attached to a first portion of the flexible film; surface metallization (616) in the flexible material and a second portion of the flexible film, the flexible film having at least two tracks (624) extending through the surface metallization located in the second portion of the flexible film; and a floating support structure (630) comprising floating support metallization configured on the flexible material and the surface metallization, a first portion of the floating support metallization forming a central support (626) and a second portion of the support metallization floating forming at least two extensions (628) from the central support and extending in the at least two ways; (b) a base member (710) having at least one conductive base support (712); and (c) a conductive material coupling the surface metallization and the at least one base support. The package of claim 19, wherein the conductive material is a welding sphere or a conductive polymer, wherein the base member is a printed circuit board, a multi-chip module, a semiconductor chip, a chip, a passive component or a flexible interconnecting layer structure, and further including a mounting member (742) having at least one conductive mounting support (740) and a second conductive material coupling the central support of the floating support structure and the at least one mounting support. RESU MEN An interface includes floating support metallization (30 or 630) configured on a dielectric interface layer with a first portion forming a central support (26 or 626) and a second portion forming an extension (28 or 628) from the central support that extends in an interface way. Another interface includes a floating contact structure including electrically conductive material (214) which covers an orifice with at least part of the floating support metallization forming an extension (216) from the orifice. A conductive contact area interface includes at least one interface structure (22, 24, 26, 28 or 30) coupled between first and second contact areas (1 12 and 18) and including an electrical conductor having a partially open interior to form a deformable joint between the first and second contact areas.