Disclosed is a method of bonding two copper structures involving compressing a first copper structure with a second copper structure under a stress from 0.1 MPa to 50 MPa and under a temperature of 250 C. or less so that a bonding surface of the first copper structure is bonded to a bonding surface of the second copper structure; at least one of the bonding surface of the first copper structure and the bonding surface of the second copper structure have a layer of nanograins of copper having an average grain size of 5 nm to 500 nm, the layer of the nanograins of copper having a thickness of 10 nm to 10 m.

A semiconductor device includes an N-type semiconductor substrate comprising silicon, an N-type low-concentration impurity layer that is in contact with the upper surface of the N-type semiconductor substrate, a metal layer that is in contact with the entire lower surface of the N-type semiconductor substrate and has a thickness of at least 20 m, and first and second vertical MOS transistors formed in the low-concentration impurity layer. The ratio of the thickness of the metal layer to the thickness of a semiconductor layer containing the N-type semiconductor substrate and the low-concentration impurity layer is greater than 0.27. The semiconductor device further includes a support comprising a ceramic material and bonded to the entire lower surface of the metal layer only via a bonding layer.

A copper paste for pressureless bonding is a copper paste for pressureless bonding, containing: metal particles; and a dispersion medium, in which the metal particles include sub-micro copper particles having a volume average particle diameter of greater than or equal to 0.01 m and less than or equal to 0.8 m, and micro copper particles having a volume average particle diameter of greater than or equal to 2.0 m and less than or equal to 50 m, and the dispersion medium contains a solvent having a boiling point of higher than or equal to 300 C., and a content of the solvent having a boiling point of higher than or equal to 300 C. is greater than or equal to 2 mass % on the basis of a total mass of the copper paste for pressureless bonding.

A semiconductor device includes an N-type semiconductor substrate comprising silicon, an N-type low-concentration impurity layer that is in contact with the upper surface of the N-type semiconductor substrate, a metal layer that is in contact with the entire lower surface of the N-type semiconductor substrate and has a thickness of at least 20 m, and first and second vertical MOS transistors formed in the low-concentration impurity layer. The ratio of the thickness of the metal layer to the thickness of a semiconductor layer containing the N-type semiconductor substrate and the low-concentration impurity layer is greater than 0.27. The semiconductor device further includes a support comprising a ceramic material and bonded to the entire lower surface of the metal layer only via a bonding layer.

A bonding material includes: fine silver particles having an average primary particle diameter of 1 to 50 nm, each of the fine silver particles being coated with an organic compound having a carbon number of not greater than 8, such as hexanoic acid; silver particles having an average primary particle diameter of 0.5 to 4 m each of the silver particles being coated with an organic compound, such as oleic acid; a solvent containing a primary alcohol solvent and a terpene alcohol solvent; and a dispersant containing a phosphoric acid ester dispersant (or a phosphoric acid ester dispersant and an acrylic resin dispersant), wherein the content of the fine silver particles is in the range of from 5 wt % to 30 wt %, and the content of the silver particles is in the range of from 60 wt % to 90 wt %, the total content of the fine silver particles and the silver particles being not less than 90 wt %, and wherein the bonding material further includes a sintering aid of a monocarboxylic acid having an ether bond.

Disclosed herein is a method of forming an electrical connecting structure having nano-twins copper. The method includes the steps of (i) forming a first nano-twins copper layer including a plurality of nano-twins copper grains; (ii) forming a second nano-twins copper layer including a plurality of nano-twins copper grains; and (iii) joining a surface of the first nano-twins copper layer with a surface of the second nano-twins copper layer, such that at least a portion of the first nano-twins copper grains grow into the second nano-twins copper layer, or at least a portion of the second nano-twins copper grains grow into the first nano-twins copper layer. An electrical connecting structure having nano-twins copper is provided as well.

Methods of bonding substrates are provided, including forming a thin film of a metal oxide on a bonding surface of both or either of a pair of substrates, at least one of which is a transparent substrate, and contacting the bonding surfaces of the pair of substrates with each other via the thin film of the metal oxide.

Provided among other things is an electrical device comprising: a first component that is a semiconductor or an electrical conductor; a second component that is an electrical conductor; and a strong, heat stable junction there between including an intermetallic bond formed of: substantially (a) tin (Sn) or a mixture of Sn and indium (In) thereof, and (b) substantially nickel (Ni). The junction can have an electrical contact resistance that is small compared to the resistance of the electrical device.

A semiconductor device includes an N-type semiconductor substrate comprising silicon, an N-type low-concentration impurity layer that is in contact with the upper surface of the N-type semiconductor substrate, a metal layer that is in contact with the entire lower surface of the N-type semiconductor substrate and has a thickness of at least 20 m, and first and second vertical MOS transistors formed in the low-concentration impurity layer. The ratio of the thickness of the metal layer to the thickness of a semiconductor layer containing the N-type semiconductor substrate and the low-concentration impurity layer is greater than 0.27. The semiconductor device further includes a support comprising a ceramic material and bonded to the entire lower surface of the metal layer only via a bonding layer.

The present invention relates to a method for producing a soldered product by which soldering can be accomplished without using a jig. The method for producing a soldered product of the present invention comprises: a provision step of providing a solder and a temporary fixing agent for temporarily fixing the solder; a temporary fixing step of temporarily fixing the solder to a soldering target with the temporary fixing agent; a vaporization step of placing the soldering target with the solder temporarily fixed thereto in a vacuum or heating the soldering target with the solder temporarily fixed thereto to a predetermined temperature lower than the melting temperature of the solder, to vaporize the temporary fixing agent in order to form gaps between the solder and the soldering target; a reduction step, performed concurrently with or after the vaporization step, of reducing, with a reducing gas at a predetermined temperature lower than the melting temperature of the solder, the solder and the soldering target left in the vaporization step; and a solder melting step, performed after the reduction step, of heating the soldering target to a predetermined temperature equal to or higher than the melting temperature of the solder to melt the solder.