A printed electrical connection structure includes a substrate having one or more electrical connection pads and a micro-transfer printed component having one or more connection posts. Each connection post is in electrical contact with a connection pad. A resin is disposed between and in contact with the substrate and the component. The resin has a reflow temperature less than a cure temperature. The resin repeatedly flows at the reflow temperature when temperature-cycled between an operating temperature and the reflow temperature but does not flow after the resin is exposed to a cure temperature. A solder can be disposed on the connection post or the connection pad. After printing and reflow, the component can be tested and, if the component fails, another component is micro-transfer printed to the substrate, the resin is reflowed again, the other component is tested and, if it passes the test, the resin is finally cured.

A printed electrical connection structure includes a substrate having one or more electrical connection pads and a micro-transfer printed component having one or more connection posts. Each connection post is in electrical contact with a connection pad. A resin is disposed between and in contact with the substrate and the component. The resin has a reflow temperature less than a cure temperature. The resin repeatedly flows at the reflow temperature when temperature-cycled between an operating temperature and the reflow temperature but does not flow after the resin is exposed to a cure temperature. A solder can be disposed on the connection post or the connection pad. After printing and reflow, the component can be tested and, if the component fails, another component is micro-transfer printed to the substrate, the resin is reflowed again, the other component is tested and, if it passes the test, the resin is finally cured.

A bond tip for thermocompression bonding a bottom surface includes a die contact area and a low surface energy material covering at least a portion of the bottom surface. The low surface energy material may cover substantially all of the bottom surface, or only a peripheral portion surrounding the die contact area. The die contact area may be recessed with respect to the peripheral portion a depth at least as great as a thickness of a semiconductor die to be received in the recessed die contact area. A method of thermocompression bonding is also disclosed.

A method to produce a semiconductor package or system-on-flex package comprising bonding structures for connecting IC/chips to fine pitch circuitry using a solid state diffusion bonding is disclosed. A plurality of traces is formed on a substrate, each respective trace comprising five different conductive materials having different melting points and plastic deformation properties, which are optimized for both diffusion bonding of chips and soldering of passives components.

A method of making a micro-transfer printed structure includes providing a destination substrate and a source substrate having one or more micro-transfer printable components. A layer of volatile adhesive is formed over the destination substrate and one or more components are micro-transfer printed from the source substrate onto the volatile adhesive layer at a non-evaporable temperature of the volatile adhesive layer. The volatile adhesive layer is then heated to an evaporation temperature to evaporate at least a portion of the volatile adhesive after micro-transfer printing. In certain embodiments, a micro-transfer printed structure includes a destination substrate having one or more metal contacts and one or more micro-transfer printable components having one or more component contacts disposed on the destination substrate with the metal contact aligned with the component contact. The metal contact can form an intermetallic bond with the component contact.

A method of making a micro-transfer printed structure includes providing a destination substrate and a source substrate having one or more micro-transfer printable components. A layer of volatile adhesive is formed over the destination substrate and one or more components are micro-transfer printed from the source substrate onto the volatile adhesive layer at a non-evaporable temperature of the volatile adhesive layer. The volatile adhesive layer is then heated to an evaporation temperature to evaporate at least a portion of the volatile adhesive after micro-transfer printing. In certain embodiments, a micro-transfer printed structure includes a destination substrate having one or more metal contacts and one or more micro-transfer printable components having one or more component contacts disposed on the destination substrate with the metal contact aligned with the component contact. The metal contact can form an intermetallic bond with the component contact.

Semiconductor devices, methods of manufacture thereof, and packaged semiconductor devices are disclosed. A method of forming a device includes forming a conductive trace over a first substrate, the conductive trace having first tapering sidewalls, forming a conductive bump over a second substrate, the conductive bump having second tapering sidewalls and a first surface distal the second substrate, and attaching the conductive bump to the conductive trace via a solder region. The solder region extends from the first surface of the conductive bump to the first substrate, and covers the first tapering sidewalls of the conductive trace. The second tapering sidewalls of the conductive bump are free of the solder region.

Semiconductor devices, methods of manufacture thereof, and packaged semiconductor devices are disclosed. A method of forming a device includes forming a conductive trace over a first substrate, the conductive trace having first tapering sidewalls, forming a conductive bump over a second substrate, the conductive bump having second tapering sidewalls and a first surface distal the second substrate, and attaching the conductive bump to the conductive trace via a solder region. The solder region extends from the first surface of the conductive bump to the first substrate, and covers the first tapering sidewalls of the conductive trace. The second tapering sidewalls of the conductive bump are free of the solder region.

A method for bonding wafers is provided. The method comprises the steps of providing a first wafer having an exposed first layer, the first layer comprising a first metal; and providing a second wafer having an exposed second layer, the second layer comprising a second metal, the first metal and the second metal capable of forming a eutectic mixture having a eutectic melting temperature. The method further comprises the steps of contacting the first layer with the second layer; and applying a predetermined pressure at a predetermined temperature to form a solid-state diffusion bond between the first layer and the second layer, wherein the predetermined temperature is below the eutectic melting temperature.

An imaging device includes a first semiconductor element including at least one bump pad that has a concave shape. The at least one bump pad includes a first metal layer and a second metal layer on the first metal layer. The imaging device includes a second semiconductor element including at least one electrode. The imaging device includes a microbump electrically connecting the at least one bump pad to the at least one electrode. The microbump includes a diffused portion of the second metal layer, and first semiconductor element or the second semiconductor element includes a pixel unit.