Abstract: A spalling method is provided that includes depositing a stressor layer on surface of a base substrate, and contacting the stressor layer with a planar transfer. The planar transfer surface is then traversed along a plane that is parallel to and having a vertical offset from the upper surface of the base substrate. The planar transfer surface is traversed in a direction from a first edge of the base substrate to an opposing second edge of the base substrate to cleave the base substrate and transfer a spalled portion of the base substrate to the planar transfer surface. The vertical offset between the plane along which the planar transfer surface is traversed and the upper surface of the base substrate is a fixed distance. The fixed distance of the vertical offset provides a uniform spalling force. A spalling method is also provided that includes a transfer roller.

Abstract: A method for spalling local areas of a base substrate utilizing at least one stressor layer portion which is located on a portion, but not all, of an uppermost surface of a base substrate. The method includes providing a base substrate having a uniform thickness and a planar uppermost surface spanning across an entirety of the base substrate. At least one stressor layer portion having a shape is formed on at least a portion, but not all, of the uppermost surface of the base substrate. Spalling is performed which removes a material layer portion from the base substrate and provides a remaining base substrate portion. The material layer portion has the shape of the at least one stressor layer portion, while the remaining base substrate portion has at least one opening located therein which correlates to the shape of the at least one stressor layer.

Abstract: A method of controlled layer transfer is provided. The method includes providing a stressor layer to a base substrate. The stressor layer has a stressor layer portion located atop an upper surface of the base substrate and a self-pinning stressor layer portion located adjacent each sidewall edge of the base substrate. A spalling inhibitor is then applied atop the stressor layer portion of the base substrate, and thereafter the self-pinning stressor layer portion of the stressor layer is decoupled from the stressor layer portion. A portion of the base substrate that is located beneath the stressor layer portion is then spalled from the original base substrate. The spalling includes displacing the spalling inhibitor from atop the stressor layer portion. After spalling, the stressor layer portion is removed from atop a spalled portion of the base substrate.

Abstract: A process and apparatus for forming and transferring metal arrays of balls and shapes is described incorporating molds, tape, injection molded metal such as solder, metal reflow and a mask on a substrate for shearing solidified metal of metal arrays into respective openings in the mask.

Abstract: A spalling method is provided that includes depositing a stressor layer on surface of a base substrate, and contacting the stressor layer with a planar transfer. The planar transfer surface is then traversed along a plane that is parallel to and having a vertical offset from the upper surface of the base substrate. The planar transfer surface is traversed in a direction from a first edge of the base substrate to an opposing second edge of the base substrate to cleave the base substrate and transfer a spalled portion of the base substrate to the planar transfer surface. The vertical offset between the plane along which the planar transfer surface is traversed and the upper surface of the base substrate is a fixed distance. The fixed distance of the vertical offset provides a uniform spalling force. A spalling method is also provided that includes a transfer roller.

Abstract: Solder bumps are provided on round wafers through the use of injection molded solder. Copper pillars or ball limiting metallurgy are formed over I/O pads within the channels of a patterned mask layer. Solder is injected over the pillars or BLM, filling the channels. Molten solder can be injected in cavities formed in round wafers without leakage using a carrier assembly that accommodates wafers that have been previously subjected to mask layer deposition and patterning. One such carrier assembly includes an elastomeric body portion having a round recess, the walls of the recess forming a tight seal with the round wafer. Other carrier assemblies employ adhesives applied around the peripheral edges of the wafers to ensure sealing between the carrier assemblies and wafers.

Abstract: Multiple injections of molten solder are employed to form double solder bumps having outer layers that melt at lower temperatures than the inner portions thereof. During a flip chip assembly process, the reflow temperature is above the melting temperature of the outer layers and below the melting temperature of the inner portions of the solder bumps. As the inner portions of the solder bumps do not collapse during reflow, a flip chip assembly can be made at relatively low temperatures and have a high stand-off height. A structure having double solder bumps facilitates flip chip assembly.

Abstract: An apparatus for transferring metal solidified in blind cavities is described incorporating a first flexible tape having blind cavities, a second flexible tape having adhesive regions, rollers for guiding respective tapes and means for moving respective tapes. Also a conveyor belt having blind or through cavities, rollers and a vibration transducer or pressurized gas is described to release solidified metal in the cavities.

Abstract: The present invention relates generally to thermally-conductive pastes for use with integrated circuits, and particularly, but not by way of limitation, to self-orienting microplates of graphite.

Abstract: Methods for removing a material layer from a base substrate utilizing spalling in which mode III stress, i.e., the stress that is perpendicular to the fracture front created in the base substrate, during spalling is reduced. The substantial reduction of the mode III stress during spalling results in a spalling process in which the spalled material has less surface roughness at one of its' edges as compared to prior art spalling processes in which the mode III stress is present and competes with spalling.

Abstract: The present invention relates generally to thermally-conductive pastes for use with integrated circuits, and particularly, but not by way of limitation, to self-orienting microplates of graphite.

Abstract: A method for spalling local areas of a base substrate utilizing at least one stressor layer portion which is located on a portion, but not all, of an uppermost surface of a base substrate. The method includes providing a base substrate having a uniform thickness and a planar uppermost surface spanning across an entirety of the base substrate. At least one stressor layer portion having a shape is formed on at least a portion, but not all, of the uppermost surface of the base substrate. Spalling is performed which removes a material layer portion from the base substrate and provides a remaining base substrate portion. The material layer portion has the shape of the at least one stressor layer portion, while the remaining base substrate portion has at least one opening located therein which correlates to the shape of the at least one stressor layer.

Abstract: A stressor layer used in a controlled spalling method is removed through the use of a cleave layer that can be fractured or dissolved. The cleave layer is formed between a host semiconductor substrate and the metal stressor layer. A controlled spalling process separates a relatively thin residual host substrate layer from the host substrate. Following attachment of a handle substrate to the residual substrate layer or other layers subsequently formed thereon, the cleave layer is dissolved or otherwise compromised to facilitate removal of the stressor layer. Such removal allows the fabrication of a bifacial solar cell.

Abstract: A stressor layer used in a controlled spalling method is removed through the use of a cleave layer that can be fractured or dissolved. The cleave layer is formed between a host semiconductor substrate and the metal stressor layer. A controlled spalling process separates a relatively thin residual host substrate layer from the host substrate. Following attachment of a handle substrate to the residual substrate layer or other layers subsequently formed thereon, the cleave layer is dissolved or otherwise compromised to facilitate removal of the stressor layer. Such removal allows the fabrication of a bifacial solar cell.

Abstract: A process and apparatus for forming and transferring metal arrays of balls and shapes is described incorporating molds, tape, injection molded metal such as solder, metal reflow and a mask on a substrate for shearing solidified metal of metal arrays into respective openings in the mask.

Abstract: A process and tools for forming and/or releasing metal preforms, metal shapes and solder balls is described incorporating flexible molds or sheets, injection molded metal such as solder and in the case of solder balls, a liquid or gaseous environment to reduce or remove metal oxides prior to or during metal (solder) reflow to increase surface tension to form spherical or substantially spherical solder-balls.

Abstract: An assembly is obtained; it includes a substrate; a plurality of wet-able pads formed on a surface of the substrate; and a solder resist layer deposited on the surface of the substrate and having an outer surface. At least the solder resist layer is formed with recessed regions defining volumes adjacent the wet-able pads. Molten solder is directly injected into the volumes adjacent the wet-able pads, such that the volumes adjacent the wet-able pads are filled with solder. The solder is allowed to solidify. It forms a plurality of solder structures adhered to the wet-able pads. The substrate and the solder are re-heated after the solidification, to re-flow the solder into generally spherical balls extending above the outer surface of the solder resist layer. The volumes adjacent the wet-able pads are configured and dimensioned to receive sufficient solder in the injecting step such that the generally spherical balls extend above the outer surface of the solder resist layer as a result of the re-heating step.

Abstract: Manufacturing a thin film direct bandgap semiconductor active solar cell device comprises providing a source substrate having a surface and disposing on the surface a stress layer having a stress layer surface area in contact with and bonded to the surface of the source substrate. Operatively associating a handle foil with the stress layer and applying force to the handle foil separates the stress layer from the source substrate, and leaves a portion of the source substrate on the stress layer surface substantially corresponding to the area in contact with the surface of the source substrate. The portion is less thick than the source layer. The stress layer thickness is below that which results in spontaneous spalling of the source substrate. The source substrate may comprise an inorganic single crystal or polycrystalline material such as Si, Ge, GaAs, SiC, sapphire, or GaN. The stress layer may comprise a flexible material.

Abstract: A base layer of a semiconductor material is formed with a naturally textured surface. The base layer may be incorporated within a photovoltaic structure. A controlled spalling technique, in which substrate fracture is propagated in a selected direction to cause the formation of facets, is employed. Spalling in the [110] directions of a (001) silicon substrate results in the formation of such facets of the resulting base layer, providing a natural surface texture.

Abstract: A spalling method is provided that includes depositing a stressor layer on surface of a base substrate, and contacting the stressor layer with a planar transfer. The planar transfer surface is then traversed along a plane that is parallel to and having a vertical offset from the upper surface of the base substrate. The planar transfer surface is traversed in a direction from a first edge of the base substrate to an opposing second edge of the base substrate to cleave the base substrate and transfer a spalled portion of the base substrate to the planar transfer surface. The vertical offset between the plane along which the planar transfer surface is traversed and the upper surface of the base substrate is a fixed distance. The fixed distance of the vertical offset provides a uniform spalling force. A spalling method is also provided that includes a transfer roller.