A semiconductor-mounted product includes a semiconductor package, a wiring substrate, four or more soldered portions, and a resin-reinforced portion. Each of the soldered portions electrically connects the semiconductor package to the wiring of the wiring substrate. The resin-reinforced portion is formed on a side surface of each of the soldered portions. Each of the soldered portions has a first solder region formed closer to the semiconductor package than the wiring substrate and a second solder region formed closer to the wiring substrate than the semiconductor package. A proportion of a void present in a polygon connecting centers of soldered portions located at outermost positions among the soldered portions to a sum of the void and the resin-reinforced portion is from 10% to 99%, inclusive.

A semiconductor-mounted product includes a semiconductor package, a wiring substrate, four or more soldered portions, and a resin-reinforced portion. Each of the soldered portions electrically connects the semiconductor package to the wiring of the wiring substrate. The resin-reinforced portion is formed on a side surface of each of the soldered portions. Each of the soldered portions has a first solder region formed closer to the semiconductor package than the wiring substrate and a second solder region formed closer to the wiring substrate than the semiconductor package. A proportion of a void present in a polygon connecting centers of soldered portions located at outermost positions among the soldered portions to a sum of the void and the resin-reinforced portion is from 10% to 99%, inclusive.

A micro light emitting diode (LED) transfer device includes a transfer part configured to transfer a relay substrate having at least one micro LED; a mask having openings corresponding to a position of the at least one micro LED; a first laser configured to irradiate a first laser light having a first wavelength to the mask; a second laser configured to irradiate a second laser light having a second wavelength different from the first wavelength to the mask; and a processor configured to: control the at least one micro LED to contact a coupling layer of a target substrate, and based on the coupling layer contacting the at least one micro LED, control the first laser to irradiate the first laser light toward the at least one micro LED, and subsequently control the second laser to irradiate the second laser light toward the at least one micro LED.

A micro light emitting diode (LED) transfer device includes a transfer part configured to transfer a relay substrate having at least one micro LED; a mask having openings corresponding to a position of the at least one micro LED; a first laser configured to irradiate a first laser light having a first wavelength to the mask; a second laser configured to irradiate a second laser light having a second wavelength different from the first wavelength to the mask; and a processor configured to: control the at least one micro LED to contact a coupling layer of a target substrate, and based on the coupling layer contacting the at least one micro LED, control the first laser to irradiate the first laser light toward the at least one micro LED, and subsequently control the second laser to irradiate the second laser light toward the at least one micro LED.

A method of making an assembly can include juxtaposing a top surface of a first electrically conductive element at a first surface of a first substrate with a top surface of a second electrically conductive element at a major surface of a second substrate. One of: the top surface of the first conductive element can be recessed below the first surface, or the top surface of the second conductive element can be recessed below the major surface. Electrically conductive nanoparticles can be disposed between the top surfaces of the first and second conductive elements. The conductive nanoparticles can have long dimensions smaller than 100 nanometers. The method can also include elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles can cause metallurgical joints to form between the juxtaposed first and second conductive elements.

A micro light emitting diode (LED) transfer device includes a transfer part configured to transfer a relay substrate having at least one micro LED; a mask having openings corresponding to a position of the at least one micro LED; a first laser configured to irradiate a first laser light having a first wavelength to the mask; a second laser configured to irradiate a second laser light having a second wavelength different from the first wavelength to the mask; and a processor configured to: control the at least one micro LED to contact a coupling layer of a target substrate, and based on the coupling layer contacting the at least one micro LED, control the first laser to irradiate the first laser light toward the at least one micro LED, and subsequently control the second laser to irradiate the second laser light toward the at least one micro LED.

A micro light emitting diode (LED) transfer device includes a transfer part configured to transfer a relay substrate having at least one micro LED; a mask having openings corresponding to a position of the at least one micro LED; a first laser configured to irradiate a first laser light having a first wavelength to the mask; a second laser configured to irradiate a second laser light having a second wavelength different from the first wavelength to the mask; and a processor configured to: control the at least one micro LED to contact a coupling layer of a target substrate, and based on the coupling layer contacting the at least one micro LED, control the first laser to irradiate the first laser light toward the at least one micro LED, and subsequently control the second laser to irradiate the second laser light toward the at least one micro LED.

A method of making an assembly can include juxtaposing a top surface of a first electrically conductive element at a first surface of a first substrate with a top surface of a second electrically conductive element at a major surface of a second substrate. One of: the top surface of the first conductive element can be recessed below the first surface, or the top surface of the second conductive element can be recessed below the major surface. Electrically conductive nanoparticles can be disposed between the top surfaces of the first and second conductive elements. The conductive nanoparticles can have long dimensions smaller than 100 nanometers. The method can also include elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles can cause metallurgical joints to form between the juxtaposed first and second conductive elements.

A method of making an assembly can include juxtaposing a top surface of a first electrically conductive element at a first surface of a first substrate with a top surface of a second electrically conductive element at a major surface of a second substrate. One of: the top surface of the first conductive element can be recessed below the first surface, or the top surface of the second conductive element can be recessed below the major surface. Electrically conductive nanoparticles can be disposed between the top surfaces of the first and second conductive elements. The conductive nanoparticles can have long dimensions smaller than 100 nanometers. The method can also include elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles can cause metallurgical joints to form between the juxtaposed first and second conductive elements.

A method of making an assembly can include juxtaposing a top surface of a first electrically conductive element at a first surface of a first substrate with a top surface of a second electrically conductive element at a major surface of a second substrate. One of: the top surface of the first conductive element can be recessed below the first surface, or the top surface of the second conductive element can be recessed below the major surface. Electrically conductive nanoparticles can be disposed between the top surfaces of the first and second conductive elements. The conductive nanoparticles can have long dimensions smaller than 100 nanometers. The method can also include elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles can cause metallurgical joints to form between the juxtaposed first and second conductive elements.