Senju Metal Industry Co., Ltd.

Other

Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Nippondenso Co., Ltd.

Nissan Chemical Industries Limited

Nisshin Steel Co., Ltd.

Toshihiko Taguchi

Masahiko Hirata

Yoshitaka Toyoda

Takashi Nagashima

Hisahiko Yoshida

Kunihito Takaura

Hiroji Noguchi

Shozo Asano

Tsukasa Ohnishi

Takashi Hori

Rikiya Katoh

Toshikazu Murata

Ryo Oishi

Sadao Kishida

Ryoichi Suzuki

Yuji Kawamata

Hisao Ikeda

Osamu Munekata

Takehiko Ito

Masato Shimamura

Tomohiko Iino

Kazuo Fujikura

Masaki Sanji

Hiroo Nagai

Ken'ichi Osawa

Satoru Akita

Eikichi Takahashi

Tetsuya Okuno

Masanobu Okuyama

Akiko Iwano

Hisayuki Abe

Kouichi Ootuka

Setsuko Tadokoro

Toshihisa Sudo

An inexpensive lead-free solder which prevents the occurrence of tin pest at extremely low temperatures and which has good wettability and impact resistance has a composition consisting essentially of, in mass %, Cu: 0.5-0.8%, Bi: at least 0.1% and less than 1%, Ni: 0.02-0.04%, and a remainder of Sn.

Lead-free solder

In a solder paste formed by blending an alloy powder and a flux, the alloy powder is a powder mixture formed by mixing at least one powder of a Sn&#x2014;Zn based alloy and at least one powder of a Sn&#x2014;Ag based alloy. The alloys powders are blended so that the composition of the powder mixture is 5-10 mass % of Zn; 0.005-1.5 mass % of Ag; optionally at least one of 0.002-1.0 mass % of Cu, 0.005-15 mass % of Bi, 0.005-15 mass % of In, and 0.005-1.0 mass % of Sb; and a remainder of Sn.

Solder paste and printed circuit board

The present invention provides a Sn&#x2014;Zn based lead-free solder which can prevent peeling of solder from soldered portions even after the passage of long periods after soldering of portions to be soldered made of Cu. A Sn&#x2014;Zn based lead-free solder according to the present invention comprises 5-10 mass percent of Zn, a total of 0.005-1.0 mass percent of at least one substance selected from the group consisting of Au, Pt, Pd, Fe, and Sb, optionally a total of at most 15 mass percent of at least one substance selected from the group consisting of Bi and In, and a remainder of Sn. This Sn&#x2014;Zn based lead-free solder can be made into a solder paste using a rosin flux containing a halide such as an amine hydrochloride as an activator.

Lead-free solder and soldered article

A solder paste comprising a powder of a Zn-containing Sn-based, lead-free solder mixed with an activator-containing rosin-based flux to which 0.5-10.0 wt % of isocyanuric acid or a haloalkyl ester thereof is added can prevent the formation of solder balls and voids during reflow soldering and exhibit good solderability. A solder paste comprising a powder of an Ag- or Zn-containing Sn-based, lead-free solder mixed with an activator-containing rosin-based flux to which 0.01-10.0 wt % of a salicylamide compound also does not exhibit a change in viscosity and exhibits good solderability.

Solder paste

A lead-free solder paste suitable for reflow soldering includes a plurality of different types of metal powder mixed with a flux. One of the metal powders is a Sn alloy powder. Another of the metal powders is selected from a Sn alloy powder, elemental Ag powder, elemental Cu powder, and elemental Sn powder. Each Sn alloy powder includes 0-8 mass % of Ag, 0-5 mass % of Cu, and at least 80 mass % of Sn. The plurality of metal powders have a composition when melted of 1-5 mass % Ag, 0.5-3 mass % Cu, and a remainder of Sn.

Lead-free solder paste for reflow soldering

A lead-free solder paste comprises an Sn&mdash;Zn based lead-free solder powder mixed with a flux. The flux contains at least one aromatic hydroxycarboxylic acid selected from the group consisting of aromatic carboxylic acids having one hydroxyl group in a meta position (such as 3-hydroxy-2-methylbenzoic acid) and aromatic carboxylic acids having at least two hydroxyl groups (such as dihydroxynaphthoic acid or dihydroxybenzoic acid) in an amount of 0.1-10.0 mass %. The flux may further include 0.5-20 mass % of an aliphatic hydroxy carboxylic acid (such as hydroxyoleic acid).

A lead-free solder alloy which has a relatively low melting temperature and which is suitable for soldering electronic devices consists essentially of from 5 to 9 mass % of Zn, from 2 to 15 mass % of Bi, optionally from 0.001 to 1 mass % of P or from 0.001 to 0.1 mass % of Ge, and a balance of Sn. The solder alloy has a liquidus temperature of at most 220&deg; C.

Lead-free solder alloys

A lead-free solder alloy having a relatively low melting temperature and suitable for use to solder electronic devices consists essentially of: from 7 to 10 wt % of Zn; at least one of from 0.01 to 1 wt % of Ni, from 0.1 to 3.5 wt % of Ag, and from 0.1 to 3 wt % of Cu; optionally at least one of from 0.2 to 6 wt % of Bi, from 0.5 to 3 wt % of In, and from 0.001 to 1 wt % of P; and a balance of Sn. Another such lead-free solder alloy consists essentially of: from 2 to 10 wt % of Zn; from 10 to 30 wt % of Bi; from 0.05 to 2 wt % of Ag; optionally from 0.001 to 1 wt % of P, and a balance of Sn. These solder alloys have a tensile strength of at least 5 kgf/mm and at least 10% elongation.

A solder paste having a powder of a Zn-containing solder alloy such as an Sn&mdash;Zn based alloy in admixture with a soldering flux such as a rosin flux is improved by adding from 0.1% to 5.0% by weight of a glycidyl ether compound such as alkyl, alkenyl, or aryl glycidyl ether. The improved solder paste has increased resistance to aging and to concomitant deterioration in solderability caused by reaction of Zn in the solder alloy with ingredients in the flux and has a substantially extended shelf life.

Lead-free zinc-containing solder paste

A soldering flux suitable for soldering of small electronic components comprises 0.1-50 mass percent of an organic acid, 5-40 mass percent of a solvent, and 10-95 mass percent of a thermosetting resin (including a curing agent), which is preferably a bisphenol A epoxy resin and an acid anhydride or amine curing agent. This flux can be used to prepare a solder paste by mixing with solder powder. This soldering flux can secure an electronic component simultaneously by soldering and by the resin, simply by a soldering operation at a soldering temperature of at least 150&deg; C., and cleaning after soldering is no longer necessary.

Thermosetting soldering flux and soldering process

A lead-free solder alloy having a relatively low melting temperature and suitable for use to solder electronic devices consists essentially of: from 7 to 10 wt % of Zn; at least one of from 0.01 to 1 wt % of Ni, from 0.1 to 3.5 wt % of Ag, and from 0.1 to 3 wt % of Cu; optionally at least one of from 0.2 to 6 wt % of Bi, from 0.5 to 3 wt % of In, and from 0.001 to 1 wt % of P; and a balance of Sn. Another such lead-free solder alloy consists essentially of: from 2 to 10 wt % of Zn; from 10 to 30 wt % of Bi; from 0.05 to 2 wt % of Ag; optionally from 0.001 to 1 wt % of P, and a balance of Sn. These solder alloys have a tensile strength of at least 5 kgf/mm,and at least 10% elongation.

In order to prevent aging of an Sn--Zn system alloy solder paste, 0.5-5% by weight of a compound obtained by adding an ethylene oxide to cyclohexylamine, preferably together with 0.5-5% by weight of a polyoxyethylene alkylamine is added to a flux of said solder paste.

A solder paste suitable for use in reflow soldering of chip components having good soldering properties without causing tombstoning comprises a solder powder admixed with a viscous flux. The solder powder is comprised of a twin peak solder alloy consisting essentially, on a weight basis, of: 60-65% Sn, 0.1-0.6% Ag, 0.1-2% Sb, and a balance of Pb, and having a liquidus temperature below 200.degree. C.

Solder paste for chip components

A paste solder with minimized flux residue remaining after soldering comprises a powdered solder and a flux in admixture. The flux comprises from about 5% to about 40% by weight of carrier components which comprise a rosin or a rosin derivative, an activating agent, and a thixotropic agent and from about 60% to about 95% by weight of a solvent which predominantly comprises a 2-alkyl-1,3-hexanediol having 1 to 4 carbon atoms in the alkyl group.

Paste solder with minimized residue

A water-soluble soldering flux having good solderability, removability with water, and insulation resistance comprises, as activators, a combination of tartaric acid and a hydrohalide salt of mono-, di-, or tri-ethanolamine.

Growing community of inventors

Saitama, Japan

Toshihiko Taguchi