TECHNOLOGY FOCUS - IMAGING AND COMMUNICATION - Preferred Components: The paste or ink form the back side passivation or solder contact coating for a solar cell and the secondary metal particle ratio to the multi shell metal particle is 10-99 wt.%.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The metal core is formed by copper particles (preferably solid copper or copper alloy particles). The copper particles are surrounded by a first shell of a metal forming a barrier layer, coated directly on the copper particles, and a second shell of an electrically conductive metal, forming an outer layer of the particles. The electrically conductive metal shell forms the outermost surface of the particles. The copper core of the particles has a largest diameter of less than 1-4 micron. The copper core of the particles is a crystalline or multi-crystalline nano particle (preferably the copper core has a largest diameter of less than 1-4 micron). The barrier and the electrically conductive layers are applied by electroless plating. The copper core of the particles is formed by or consists of hyper branched copper. The melting point of barrier coating is higher than that of the electrically conductive layer and the metal core particle. The barrier layer is formed by a metal layer or a partial oxide of Ni, Zn, Ti, W, Sn, In, or Ta and/or their alloyed combination. The barrier layer is formed by Al2O3, SiO2, SiN and/or SiNx. The electrically conductive metal layer is formed by Ag, Au, Pt, Pd, Sn, Zn, Pb, Bi, Ni, Ti or W and/or their alloyed combination. The electrically conductive metal layer is formed by a conductive oxide of Ag, Au, Pt, Pd, Sn, Pb, Zn, Bi, Ni, Ti or W and/or their alloyed combination. The metal core is Cu or Cu alloy with Sn, Ag, Ni, Zn, or any of their alloyed combination. The plating catalyst comprises an ammoniacal ammonium sulfate solution, palladium, hydrazine, and/or acetyl acetonate as a cleaning and activating agent for the core material plating. The plating catalyst is fixed stably to the surface of the core material by a reduction method using a non-metallic reducing agent, e.g. hydrazine, formalin or sodium potassium tartrate or their combination, optionally together with acetyl acetonate as an activator. The D90 particle size of the multi-shell copper particle is less than or equal to 100 microns, e.g. 50-0.05 micron. The average particle size of the multi-shell copper particle is less than or equal to 10 microns, e.g. 10-1 micron. The barrier layer thickness on the metal core particle is 5 nm to 5 microns and the conductive layer thickness on the outermost surface is 5 nm to 5 microns. The first or second layer on the metal core is sintered in vacuum, in high boiling point solvent or in higher pressure reactor. The electrically conductive metal layer is a metallic layer or metallic alloy with meting point of below 500 degrees C, preferably less than 200 degrees C. In the conductive paste, the D90 particle size of the multi shell copper particle is less than or equal to 50 microns, the nickel barrier coating thickness on the copper particle is at least 5 nm to 5 microns. The silver finishing coating thickness on the barrier coated copper particle is 5 nm to 5 microns. The melting point of the low melting point alloy is less than 500 degrees C, preferably less than or equal to 150 degrees C. The core is copper or copper alloy, the barrier is a metal layer or a partial oxide of Ni, Zn, Ti, W, Sn, In, or Ta and/or their alloyed combination and the electrically conductive metal layer is formed by Ag, Au, Pt, Pd, Sn, Zn, Pb Bi, Ni, Ti or W and/or their alloyed combination. Preferred Composition: The composition is provided in the form of a powder. The paste comprises the composition. The composition comprises low melting point particles with melting point alloy less than 500 degrees C, preferably less than 200 degrees C, the low melting point alloy forms an electrically conductive bridge between the multi shell metallic particle at a lower melting point than the melting point of the outermost layer of the multi shell particle. Preferred Method: The core particles, which have a noble metal ion capturing ability, are allowed to capture noble metal ions, and then the noble metal ions are reduced so that the surfaces of the core particles support the noble metal. The core particles supporting the noble metal are dispersed in an initial thin film-forming solution containing nickel ions, reducing agent, and complexing agent which composed of an organic carboxylic acid or its salt so that nickel ions are reduced to form initial thin nickel films on the surfaces of the core particles. In the electroless plating step, a nickel ion containing solution containing the same complexing agent and reducing agent-containing solution are individually and simultaneously added to an aqueous solution containing the core particles provided with the nickel initial thin films and the complexing agent to carry out electroless plating.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The multi-shell metal particle surface is treated with an additive or surfactant. EXAMPLE - 50 g Copper powder having particle size having average particle of less than 5 microns were plated in an electro less nickel bath with the following composition: 20 g/l Nickelsulfate, 10 g/l Citric acid, and total of 120 g sodium hypofosfite for 60 minutes during the electroless plating process at 85-95 degrees C. The precipitate was removed from the solution by filtration, dried and optionally wasted with deionized water and dried again. Nickel coated copper powder was plated in an electroless silver bath with the following composition: 5-10 g/l silvernitrate, 110 g/l succinimide, and sodium hydroxide to bring the alkalinity to pH 8-9. The nickelplated copper powder was then immersed in the silver electrolyte for 60 minutes during the electroless plating process at 50 degrees C. The powder was greyish black and showed good conductivity by four point probe apparatus.