Provided are an ultrasonic probe and a method of manufacturing the same. The ultrasonic probe includes: a first unit configured to generate an ultrasonic wave from a first electrical signal or generate a second electrical signal from an echo signal of the ultrasonic wave; a second unit configured to provide the first electrical signal to the first unit or receive the second electrical signal from the first unit; and a third unit configured to electrically connect the first unit to the second unit, the third unit comprising a plurality of conductive bumps spaced apart from one another and a non-conductive paste or film that surrounds the plurality of conductive bumps.

Provided is a flux which can remove metal oxides to improve solder wettability and can fix the object to be soldered with flux residue. The flux contains thermosetting resin, and long-chain dibasic acid mixture including one or more species of first long-chain dibasic acid having an alkyl group in a side chain, the first long-chain dibasic acid being added as a hardening agent for hardening the thermosetting resin and an activator, and second long-chain dibasic acid having an alkyl group and an alkoxycarbonyl group in a side chain and having carbon number of 8 or more in a main chain between the carboxyl groups at opposite terminals. It is preferable that content of the thermosetting resin is 30% through 70% and content of the long-chain dibasic acid mixture is 20% through 60%.

A method of forming a metal bonding layer includes forming first and second bonding metal layers on one surfaces of first and second bonding objects, respectively. The second bonding object is disposed on the first bonding object such that the first bonding metal layer and the second bonding metal layer face each other. A eutectic metal bonding layer is formed through a reaction between the first and second bonding metal layers. At least one of the first bonding metal layer and the second bonding metal layer includes an oxidation prevention layer formed on an upper surface thereof. The oxidation prevention layer is formed of a metal having an oxidation reactivity lower than an oxidation reactivity of the bonding metal layer on the upper surface which the oxidation prevention layer is disposed.

A solder alloy comprising: from 40 to 65 wt. % bismuth; from I to IO wt. % indium; at least one of: from 0.1 to 5 wt. % gallium, from 0.1 to 5 wt. % zinc, from 0.1 to 2 w. % copper, from 0.01 to 0.1 wt. % cobalt, from 0.1 to 2 wt. % silver, from 0.005 to 0.05 wt. % titanium, and from 0.01 to 1 wt. % nickel; optionally up to 1 wt. % of one or more of: vanadium, rare earth metals, neodymium, chromium, iron, aluminium, phosphorus, gold, tellurium, selenium, calcium, vanadium, molybdenum, platinum, magnesium, silicon, and manganese; and the balance tin together with any unavoidable impurities.

Using flux to suppress increase in the viscosity of solder paste during its storage and also to improve the fusibility of a solder alloy. The flux, which contains an activator and a solvent, forms solder paste by being mixed with a granular solder alloy. The flux contains a monoalkyl propylene glycol-based solvent. It is preferable that the monoalkyl propylene glycol-based solvent is butyl propylene triglycol or butyl propylene diglycol. It is also preferable that the amount of monoalkyl propylene glycol-based solvent is equal to or more than 75 percent by mass but less than 100 percent by mass of the amount of all the solvents.

Provided is a solder material that has a high melting point and exhibits superior mechanical characteristics, and therefore can form a connecting portion with high heat-resistant reliability.

A lead-free solder alloy comprising 35-59 wt % Bi, Mn in a concentration up to 1.0 wt %, Cu in a concentration of up to 1 wt %, and balance Sn, together with any unavoidable impurities. Some embodiments also contain up to about 1 wt % Ag.

A semiconductor package includes a first substrate, a second substrate, a composite solder ball and a first semiconductor component. The composite solder ball includes a core, an encapsulating layer and a barrier layer. The composite solder ball is disposed between the first substrate and the second substrate for electrically connecting the first substrate and the second substrate. The barrier layer is disposed between the core and the encapsulating layer. Wherein a melting point of the barrier layer is higher than a melting point of the core, the melting point of the core is higher than a melting point of the encapsulating layer. The first semiconductor component is disposed between the first substrate and the second substrate.

A solder paste having improved self alignment for soldering is provided. The solder paste includes a solder powder; a composite epoxy resin containing a first epoxy resin that is solid at 25 C., and a second epoxy resin that is liquid at 25 C.; and a curing agent, wherein the first epoxy resin has a softening point that is at least 10 C. lower than the melting point of the solder powder, and is contained in a range of 10 weight parts to 75 weight parts with respect to the total 100 weight parts of the composite epoxy resin.

A solder paste consists of an amount of a first solder alloy powder between 44 wt % to less than 60 wt %; an amount of a second solder alloy powder between greater than 0 wt % and 48 wt %; and a flux; wherein the first solder alloy powder comprises a first solder alloy that has a solidus temperature above 260 C.; and wherein the second solder alloy powder comprises a second solder alloy that has a solidus temperature that is less than 250 C. In another implementation, the solder paste consists of an amount of a first solder alloy powder between 44 wt % and 87 wt %; an amount of a second solder alloy powder between 13 wt % and 48 wt %; and flux.