Overview

This Part 1-2 of the standard series IEC 61190 specifies the general requirements for the characterization and testing of soldering pastes used for high-quality interconnects in electronics assembly. This standard is a quality control document and is not intended to relate directly to the material characteristics in the manufacturing process. Relevant information on the characterization and quality testing of fluxes and the specifications for fluxes and flux containing materials are given in IEC 61190-1-1. The particle size of soldering powder shall be determined in accordance with this standard. Alternative test methods may be agreed between user and supplier. During the test, the particle size type of the powder shall be classified according to either a standard particle size or the nearest value of the particle sizes given in Table 2. The percentage of metal contained in the soldering powder should be between 65 % (m/m) and 95 % (m/m) when testing in accordance with IEC 61189-5-3. The percentage of contained metal shall be within ± 1 % of the rated value specified in the user's order. The measured viscosity shall be within ± 10 % of the value specified by the user. For the solder ball test, the solder paste shall meet the requirements regarding statistically distributed solder particles (solder balls) as specified. If the soldering paste is to melt in a nitrogen atmosphere, as for example in case of a contained soldering paste, solder ball testing in a controlled nitrogen atmosphere should be permitted. When testing the adhesiveness, the soldering paste shall be tested in accordance with IEC 61189-5-3. The minimum value of adhesion and its durability shall be subject to agreement between user and supplier. For the wetting test in accordance with IEC 61189-5-3, the copper surfaces of the test sheet section shall be wetted evenly and without any signs of dewetting or nonwetting. The supplier shall label each solder paster container with the following information: supplier's name and address, classification/designation of the paste and supplier's designation of the soldering paste, net weight of the paste, batch number, manufacturing date and shelf life. Qualification testing may be conducted by a laboratory accepted by the user on samples which have been prepared using equipment and procedures that are also used in the normal production process. Annex A gives a form sheet for the test report on soldering paste. Annex B outlines the condition and profile for reflow. Despite the fact that a number of factors may cause formation of solder balls, solder beads and splashes during reflow, the introduction of "no-clean" methods into electronics manufacturing has led to an increased formation of solder balls. The formation of solder balls, usually with a diameter of 0,5 mm, is caused when one or more solder parts are separated from a solder connection. The responsible committee is DKE/K 682 "Montageverfahren für elektronische Baugruppen" ("Electronics assembly technology") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.

Document: references other documents

Responsible national committee

DKE/K 682 - Aufbau- und Verbindungstechnik für elektronische Baugruppen