Produced is a metal ball which suppresses an emitted dose. Contained are the steps of melting a pure metal by heating the pure metal at a temperature which is higher than a boiling point of an impurity to be removed, higher than a melting point of the pure metal, and lower than a boiling point of the pure metal, the pure metal containing a U content of 5 ppb or less, a Th content of 5 ppb or less, purity of 99.9% or more and 99.995% or less, and a Pb or Bi content or a total content of Pb and Bi of 1 ppm or more, and the pure metal having the boiling point higher than the boiling point at atmospheric pressure of the impurity to be removed; and sphering the molten pure metal in a ball.

Produced is a metal ball which suppresses an emitted dose. Contained are the steps of melting a pure metal by heating the pure metal at a temperature which is higher than a boiling point of an impurity to be removed, higher than a melting point of the pure metal, and lower than a boiling point of the pure metal, the pure metal containing a U content of 5 ppb or less, a Th content of 5 ppb or less, purity of 99.9% or more and 99.995% or less, and a Pb or Bi content or a total content of Pb and Bi of 1 ppm or more, and the pure metal having the boiling point higher than the boiling point at atmospheric pressure of the impurity to be removed; and sphering the molten pure metal in a ball.

Produced is a metal ball which suppresses an emitted dose. Contained are the steps of melting a pure metal by heating the pure metal at a temperature which is higher than a boiling point of an impurity to be removed, higher than a melting point of the pure metal, and lower than a boiling point of the pure metal, the pure metal containing a U content of 5 ppb or less, a Th content of 5 ppb or less, purity of 99.9% or more and 99.995% or less, and a Pb or Bi content or a total content of Pb and Bi of 1 ppm or more, and the pure metal having the boiling point higher than the boiling point at atmospheric pressure of the impurity to be removed; and sphering the molten pure metal in a ball.

Produced is a metal ball which suppresses an emitted dose. Contained are the steps of melting a pure metal by heating the pure metal at a temperature which is higher than a boiling point of an impurity to be removed, higher than a melting point of the pure metal, and lower than a boiling point of the pure metal, the pure metal containing a U content of 5 ppb or less, a Th content of 5 ppb or less, purity of 99.9% or more and 99.995% or less, and a Pb or Bi content or a total content of Pb and Bi of 1 ppm or more, and the pure metal having the boiling point higher than the boiling point at atmospheric pressure of the impurity to be removed; and sphering the molten pure metal in a ball.

A method of and system for adhesive bonding. The method and system a) treat a surface of an element to be bonded to provide an adherent structure including one or more rubber compounds on the surface; b) place a polymerizable adhesive composition, including at least one photoinitiator and at least one energy converting material, in contact with the adherent structure and two or more components to be bonded to form an assembly, c) irradiated the assembly with radiation at a first wavelength, capable of conversion by the at least one energy converting material, to a second wavelength capable of activating the at least one photoinitiator to produce from the polymerizable adhesive composition a cured adhesive composition; and d) adhesively join the two or more components by way of the adherent structure and the cured adhesive composition.

A method of and system for adhesive bonding. The method and system a) treat a surface of an element to be bonded to provide an adherent structure including one or more rubber compounds on the surface; b) place a polymerizable adhesive composition, including at least one photoinitiator and at least one energy converting material, in contact with the adherent structure and two or more components to be bonded to form an assembly, c) irradiated the assembly with radiation at a first wavelength, capable of conversion by the at least one energy converting material, to a second wavelength capable of activating the at least one photoinitiator to produce from the polymerizable adhesive composition a cured adhesive composition; and d) adhesively join the two or more components by way of the adherent structure and the cured adhesive composition.

Copper or a copper alloy characterized in having an -ray emission of 0.001 cph/cm.sup.2 or less. Since recent semiconductor devices are produced to have higher density and higher capacity, there is greater risk of soft errors caused by the influence of rays emitted from materials positioned near semiconductor chips. In particular, there are strong demands for achieving higher purification of copper and copper alloys which are used near the semiconductor device, such as copper or copper alloy wiring lines, copper or copper alloy bonding wires, and soldering materials, and materials reduced in -ray emission are also demanded. Thus, the present invention elucidates the phenomenon in which rays are emitted from copper or copper alloys, and provides copper or copper alloy reduced in -ray emission which is adaptable to the demanded material, and a bonding wire in which such copper or copper alloy is used as its raw material.

Copper or a copper alloy characterized in having an -ray emission of 0.001 cph/cm.sup.2 or less. Since recent semiconductor devices are produced to have higher density and higher capacity, there is greater risk of soft errors caused by the influence of rays emitted from materials positioned near semiconductor chips. In particular, there are strong demands for achieving higher purification of copper and copper alloys which are used near the semiconductor device, such as copper or copper alloy wiring lines, copper or copper alloy bonding wires, and soldering materials, and materials reduced in -ray emission are also demanded. Thus, the present invention elucidates the phenomenon in which rays are emitted from copper or copper alloys, and provides copper or copper alloy reduced in -ray emission which is adaptable to the demanded material, and a bonding wire in which such copper or copper alloy is used as its raw material.