Method for producing a composite structure comprising the direct bonding of at least one first wafer with a second wafer, and comprising a step of initiating the propagation of a bonding wave, where the bonding interface between the first and second wafers after the propagation of the bonding wave has a bonding energy of less than or equal to 0.7 J/m.sup.2. The step of initiating the propagation of the bonding wave is performed under one or more of the following conditions: placement of the wafers in an environment at a pressure of less than 20 mbar and/or application to one of the two wafers of a mechanical pressure of between 0.1 MPa and 33.3 MPa. The method further comprises, after the step of initiating the propagation of a bonding wave, a step of determining the level of stress induced during bonding of the two wafers, the level of stress being determined on the basis of a stress parameter Ct calculated using the formula Ct=Rc/Ep, where: Rc corresponds to the radius of curvature (in km) of the two-wafer assembly and Ep corresponds to the thickness (in m) of the two-wafer assembly. The method further comprises a step of validating the bonding when the level of stress Ct determined is greater than or equal to 0.07.

A method of bonding a first substrate to a second substrate includes disposing a first high melting point metal layer onto a first substrate, disposing a first low melting point metal layer onto the first high melting point metal layer, disposing a second high melting point metal layer onto a second substrate, and disposing a second low melting point metal layer onto the second high melting point metal layer. The method further includes applying precursor metal particles onto the first and/or second low melting point metal layers, positioning the first and second low melting point metal layers such that the precursor metal particles contact both the first and second low melting point metal layers, and bonding the first substrate to the second substrate by heating the precursor metal particles and each metal layer to form an intermetallic alloy bonding layer between the first and second substrates.

A high temperature, non-cavity package for non-axial electronics is designed using a glass ceramic compound with that is capable of being assembled and operating continuously at temperatures greater that 300-400 C. Metal brazes, such as silver, silver colloid or copper, are used to connect the semiconductor die, lead frame and connectors. The components are also thermally matched such that the packages can be assembled and operating continuously at high temperatures and withstand extreme temperature variations without the bonds failing or the package cracking due to a thermal mismatch.

Bonding wire for semiconductor device use where both leaning failures and spring failures are suppressed by (1) in a cross-section containing the wire center and parallel to the wire longitudinal direction (wire center cross-section), there are no crystal grains with a ratio a/b of a long axis a and a short axis b of 10 or more and with an area of 15 m.sup.2 or more (fiber texture), (2) when measuring a crystal direction in the wire longitudinal direction in the wire center cross-section, the ratio of crystal direction <100> with an angle difference with respect to the wire longitudinal direction of 15 or less is, by area ratio, 10% to less than 50%, and (3) when measuring a crystal direction in the wire longitudinal direction at the wire surface, the ratio of crystal direction <100> with an angle difference with respect to the wire longitudinal direction of 15 or less is, by area ratio, 70% or more. During the drawing step, a drawing operation with a rate of reduction of area of 15.5% or more is performed at least once. The final heat treatment temperature and the pre-final heat treatment temperature are made predetermined ranges.

Bonding wire for semiconductor device use where both leaning failures and spring failures are suppressed by (1) in a cross-section containing the wire center and parallel to the wire longitudinal direction (wire center cross-section), there are no crystal grains with a ratio a/b of a long axis a and a short axis b of 10 or more and with an area of 15 m.sup.2 or more (fiber texture), (2) when measuring a crystal direction in the wire longitudinal direction in the wire center cross-section, the ratio of crystal direction <100> with an angle difference with respect to the wire longitudinal direction of 15 or less is, by area ratio, 50% to 90%, and (3) when measuring a crystal direction in the wire longitudinal direction at the wire surface, the ratio of crystal direction <100> with an angle difference with respect to the wire longitudinal direction of 15 or less is, by area ratio, 50% to 90%. During the drawing step, a drawing operation with a rate of reduction of area of 15.5% or more is performed at least once. The final heat treatment temperature and the pre-final heat treatment temperature are made predetermined ranges.

The present invention relates to a copper fine particle dispersion containing copper nanoparticles A, a carboxylic acid B having not less than 6 and not more than 14 carbon atoms, a compound C represented by the formula (1): RO(CH.sub.2CH.sub.2O).sub.nCH.sub.2COOH wherein R is a hydrocarbon group having not less than 6 and not more than 14 carbon atoms, and n represents an average molar number of addition of ethyleneoxy groups, and is a number of not less than 0.5 and not more than 20, and a dispersion medium D, in which the dispersion medium D contains at least one compound selected from the group consisting of a (poly)alkylene glycol, a (poly)alkylene glycol derivative, a terpene alcohol, glycerin and a glycerin derivative, a content of the carboxylic acid B in the dispersion is not less than 0.1% by mass, a content of the compound C in the dispersion is not less than 0.05% by mass, and a total content of the carboxylic acid B and the compound C in the dispersion is not more than 8% by mass, and also relates to a method for producing a bonded body, which includes the steps of allowing the aforementioned copper fine particle dispersion to intervene between a plurality of metal members, and heating the dispersion between the plurality of metal members.