Improved soldering of components with different thermal masses by hybrid printing of solder pastes
In this work are shown the results of an improved Pin in Paste (PiP) technique. With the purpose of soldering of SMD and PTH (Pinthrough Hole) components, the PiP technique is making use of solder paste printing. The problematic PtP soldering due to thermal shading of areas under large size connectors, which results from their big thermal masses, has been considered. The actual temperatures under such connectors differ from the optimum thermal profile needed for the particular solder paste which profile can be monitored by a KIC instrument. A solution of this problem is suggested by making use of a solder paste, whose optimum thermal profile corresponds to the actual thermal profile under the connector components. For that purpose are used two different kinds of solder pastes. The proposed method, named Hybrid Printing, of two kinds of SMD pastes is based on the special design of a rakel which allows depositing of more than one kind of solder paste within one processing step. The effect of the use of Bi containing, Pb containing and Pb-free solder pastes has been investigated. The application of hybrid printing in a real production line has been demonstrated. The results of the X-ray and metallographic assessment of the fabricated solder joints are presented.
Sustainable and Secure Soldering of Complex Components with Package BGA, LGA, Flip Chip, FI WLCSP, FO WLCSP to Star Flex PCB Using Hybrid Printing
The application of hybrid printing for the sustainable and secure soldering of complex components with package BGA, LGA, Flip Chip, FI WLCSP, FO WLCSP to the Star Flex PCB is presented. Several types of solder pastes can be applied by means of hybrid print in a single printing process, which in a single reflow process allows different soldering times for different components of the board on which various thermosensitive components may be placed. This allows to obtain low-void solder of thermosensitive or complex components. Experimental results are presented using different solder pastes and various complex components. The analysis was done using microscopy and Xray imaging/analysis.
Acceptance testing of BGA ball alloys
The industry has seen the development of a wide range of new Pb-free BGA ball alloys. A significant element of uncertainty regarding these new alloys is the lack of defined data requirements for alloy acceptance. This paper describes recent efforts at Hewlett-Packard to develop Pb-free solder alloy testing requirements. To facilitate the standardization of alloy testing, the required tests are divided into three major areas. • Material properties • Solder joint reliability • Impact to manufacturing processes This paper presents the approach to assess the risk of using new Pb-free BGA ball alloys on printed circuit assemblies.