Senju Metal Industry Co., Ltd.

Yoshie Yamanaka

Tsukasa Ohnishi

Shunsaku Yoshikawa

Ken Tachibana

Masayuki A Suzuki

Hikaru Nomura

Seiko Ishibashi

Koji Watanabe

Minoru Ueshima

Kyu-Oh Lee

Yoshitsugu Sakamoto

Masato Shimamura

Kazuyori Takagi

Kenzo Tadokoro

Hiroki Ishikawa

Hiroyuki Yamada

Yutaka Chiba

Toru Hayashida

Tomoko Nonaka

Tokuro Yamaki

Mitsuhiro Kosai

A lead-free solder alloy capable of forming solder joints in which electromigration and an increase in resistance during electric conduction at a high current density are suppressed has an alloy composition consisting essentially of 1.0-13.0 mass % of In, 0.1-4.0 mass % of Ag, 0.3-1.0 mass % of Cu, a remainder of Sn. The solder alloy has excellent tensile properties even at a high temperature exceeding 100&#xb0; C. and can be used not only for CPUs but also for power semiconductors.

Lead-free solder alloy

By using a solder alloy consisting essentially of 0.2-1.2 mass % of Ag, 0.6-0.9 mass % of Cu, 1.2-3.0 mass % of Bi, 0.02-1.0 mass % of Sb, 0.01-2.0 mass % of In, and a remainder of Sn, it is possible to obtain portable devices having excellent resistance to drop impact and excellent heat cycle properties without developing thermal fatigue even when used in a high-temperature environment such as inside a vehicle heated by the sun or in a low-temperature environment such as outdoors in snowy weather.

A lead-free solder ball is provided which suppresses interfacial peeling in a bonding interface of a solder ball, fusion defects which develop between the solder ball and solder paste, and which can be used both with Ni electrodes plated with Au or the like and Cu electrodes having a water-soluble preflux applied atop Cu. The lead-free solder ball for electrodes of BGAs or CSPs consists of 1.6-2.9 mass % of Ag, 0.7-0.8 mass % of Cu, 0.05-0.08 mass % of Ni, and a remainder of Sn. It has excellent resistance to thermal fatigue and to drop impacts regardless of the type of electrodes of a printed circuit board to which it is bonded, which are Cu electrodes or Ni electrodes having Au plating or Au/Pd plating as surface treatment. The composition may include at least one element selected from Fe, Co, and Pt in a total amount of 0.003-0.1 mass % or at least one element selected from Bi, In, Sb, P, and Ge in a total amount of 0.003-0.1 mass %.

Lead-free solder ball

A lead-free solder which can reduce the occurrence of voids and a connecting member which uses the solder and has excellent adhesion, bonding strength, and workability are provided. The lead-free solder alloy contains Sn: 0.1-3% and/or Bi: 0.1-2%, and a remainder of In and unavoidable impurities and has the effect of suppressing the occurrence of voids at the time of soldering. The connecting member is prepared by melting the lead-free solder alloy, immersing a metal substrate in the melt, and applying ultrasonic vibrations to the molten lead-free solder alloy and the metal substrate to form a lead-free solder alloy layer on the surface of the metal substrate. A heat sink and a package are soldered to each other through this connecting member by reflow heating in the presence of flux.

Lead-free solder alloy, connecting member and a method for its manufacture, and electronic part

Provided is a process for mounting a BGA (Ball Grid Array) or CSP (Chip Size Package) on a printed circuit board. The process includes melting and fusing together solder paste and a solder ball. The solder ball has a solder composition that includes 0.5-1.1 mass % of Ag, 0.7-0.8 mass % of Cu, 0.05-0.08 mass % of Ni, and a remainder of Sn. In the process, the solder ball is placed on an electrode of the BGA or CSP substrate and the solder paste is applied onto an opposing electrode of the printed circuit board.

A lead-free solder ball for electrodes of a BGA or CSP comprising 0.5-1.1 mass % of Ag, 0.7-0.8 mass % of Cu, 0.05-0.08 mass % of Ni, and a remainder of Sn. Even when a printed circuit board to which the solder ball is bonded has Cu electrodes or Au-plated or Au/Pd-plated Ni electrodes, the solder ball has good resistance to drop impacts. The composition may further contain at least one element selected from Fe, Co, and Pt in a total amount of 0.003-0.1 mass % or at least one element selected from Bi, In, Sb, P, and Ge in a total amount of 0.003-0.1 mass %.

Solder used for flip chip bonding inside a semiconductor package was a Sn&#x2014;Pb solder such as a Pb-5Sn composition. Lead-free solders which have been studied are hard and easily form intermetallic compounds with Sn, so they were not suitable for a flip chip connection structure inside a semiconductor package, which requires stress relaxation properties. This problem is eliminated by a flip chip connection structure inside a semiconductor package using a lead-free solder which is characterized by consisting essentially of 0.01-0.5 mass percent of Ni and a remainder of Sn. 0.3-0.9 mass percent of Cu and 0.001-0.01 mass percent of P may be added to this solder composition.

Lead-free solder connection structure and solder ball

A semiconductor device is provided which has internal bonds which do not melt at the time of mounting on a substrate. A bonding material is used for internal bonding of the semiconductor device. The bonding material is obtained by filling the pores of a porous metal body having a mesh-like structure and covering the surface thereof with Sn or an Sn-based solder alloy.

Growing community of inventors

Tokyo, Japan

Yoshie Yamanaka