Provided are a polymer semiconductor including a first structural unit represented by Chemical Formula 1 and a second structural unit represented by Chemical Formula 2, a stretchable polymer thin film including the same, and an electronic device. ##STR00001## Definitions of Chemical Formulas 1 and 2 are as described in the detailed description.

A production method for silver fine particles retain capabilities such as conductivity and make it possible to form wiring at even lower temperatures; and silver fine particles. A silver fine particle production method in which silver powder is used to produce silver fine particles by means of a gas phase method. The silver fine particle production method has a step for supplying an organic acid to the silver fine particles. The gas phase method is, for example, a plasma method or a flame method. The silver fine particles have a surface coating that includes at least a carboxyl group.

Electroconductive two-dimensional particles composed of a layered material having one or more layers, wherein each of the one or more layers is a layer body represented by M.sub.mX.sub.n (M represents at least one group 3, 4, 5, 6 or 7 metal; X represents a carbon atom, a nitrogen atom, or a combination thereof; n represents a number from 1 to 4; m represents a number that is larger than n but not larger than 5), and a modification or terminal T (T represents at least one atom or group selected from a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom and a hydrogen atom) is present on the surface of the layer body; the Li content is from 0.0001% by mass to 0.0020% by mass; and the average value of the lengths of two-dimensional surfaces of the electroconductive two-dimensional particles is from 1.0 μm to 20 μm.

Provided is silver powder including silver particles having closed pores inside the particles, wherein when cross sections of the silver particles are observed at a magnification of 10,000, an average of numbers of the pores having Heywood diameters of 200 nm or greater relative to an area of the cross sections is 0.01 pores/μm.sup.2 or less, and wherein when the cross sections of the silver particles are observed at a magnification of 40,000, an average of numbers of the pores having Heywood diameters of 10 nm or greater but less than 30 nm relative to the area of the cross sections is 25 pores/μm.sup.2 or more.

A system and method of additively manufacturing a part including electrically conductive or static dissipating fluorine-containing polymers. The method includes depositing fluorine-containing polymer additive manufacturing material onto a build platform, selectively cross-linking portions of the deposited additive manufacturing material, and curing the selectively cross-linked portions such that the part is at least one of electrically conductive and static dissipating.

There is produced a fine silver particle dispersing solution which contains: fine silver particles (the content of silver in the fine silver particle dispersing solution being 30 to 95% by weight), which have an average primary particle diameter of greater than 100 nm and not greater than 300 nm and which are coated with an amine having a carbon number of 8 to 12, such as octylamine, serving as an organic protective material; a polar solvent (5 to 70% by weight) having a boiling point of 150 to 300° C.; and an acrylic dispersing agent (5% by weight or less with respect to the fine silver particles), such as a dispersing agent of at least one of acrylic acid ester and methacrylic acid ester.

There is produced a fine silver particle dispersing solution which contains: fine silver particles (the content of silver in the fine silver particle dispersing solution being 30 to 95% by weight), which have an average primary particle diameter of greater than 100 nm and not greater than 300 nm and which are coated with an amine having a carbon number of 8 to 12, such as octylamine, serving as an organic protective material; a polar solvent (5 to 70% by weight) having a boiling point of 150 to 300° C.; and an acrylic dispersing agent (5% by weight or less with respect to the fine silver particles), such as a dispersing agent of at least one of acrylic acid ester and methacrylic acid ester.

A conductive composition has excellent adhesiveness and conductivity. A conductive composition contains copper powder, cuprous oxide, a lead-free glass frit, and an acid-based additive. The lead-free glass frit is contained in an amount of 9 to 50 parts by mass relative to 100 parts of the copper powder. The lead-free glass frit contains a borosilicate zinc-based glass frit and a vanadium zinc-based glass frit. The borosilicate zinc-based glass frit contains boron oxide, silicon oxide, zinc oxide, and optional other components, among which boron oxide, silicon oxide, and zinc oxide serve as top-three oxide components in terms of content. The vanadium zinc-based glass frit contains vanadium oxide, zinc oxide, and optional other components, among which vanadium oxide and zinc oxide serve as top-two oxide components in terms of content. The acid-based additive is contained 0.1 to 5.0 parts by mass relative to 100 parts of the copper powder.

A joining film having sufficient connection heat resistance and high reliability, for which a joining process of joining a semiconductor element and a substrate is simple and easy, a tape for wafer processing, a method for producing a joined body, and a joined body. A joining film for joining a semiconductor element and a substrate includes an electroconductive joining layer formed by molding an electroconductive paste containing metal fine particles (P) into a film form; and a tack layer having tackiness and being laminated with the electroconductive joining layer. The tack layer is thermally decomposed by heating at the time of joining, the metal fine particles (P) of the electroconductive joining layer 13a are sintered, and thereby the semiconductor element and the substrate are joined.

A joining film having sufficient connection heat resistance and high reliability, for which a joining process of joining a semiconductor element and a substrate is simple and easy, a tape for wafer processing, a method for producing a joined body, and a joined body. A joining film for joining a semiconductor element and a substrate includes an electroconductive joining layer formed by molding an electroconductive paste containing metal fine particles (P) into a film form; and a tack layer having tackiness and being laminated with the electroconductive joining layer. The tack layer is thermally decomposed by heating at the time of joining, the metal fine particles (P) of the electroconductive joining layer 13a are sintered, and thereby the semiconductor element and the substrate are joined.