Abstract: Methods by which low melting point solder for reflow connection of components is formed on select fine and coarse pitch contacts of a printed circuit board simultaneously. A template with openings to select fine pitch circuit board contacts is placed in contact with fine pitch contacts. The fine and coarse pitch contacts of the board are exposed through holes in a stencil characterized in its ability to withstand solder reflow temperatures, not be wettable by solder, and have a coefficient of thermal expansion relatively matching the printed circuit board. Low temperature solder paste is screen deposited into the stencil openings. The solder paste retained by the template and stencil pattern is shaped during reflow to selectively form on the underlying contacts of the printed circuit board. Thereafter the board is subjected to previously practiced depositions of flux in preparation for fine and coarse pitch component placement and ensuing solder reflow.

Abstract: A method by which low melting point solder for reflow connection of components is formed on select fine and coarse pitch contacts of a printed circuit board simultaneously. A template with openings to select fine pitch circuit board contacts is placed in contact with fine pitch contacts. The fine and coarse pitch contacts of the board are exposed through holes in a stencil characterized in its ability to withstand solder reflow temperatures, not be wettable by solder, and have a coefficient of thermal expansion relatively matching the printed circuit board. Low temperature solder paste is screen deposited into the stencil openings. The stencil is removed and a mesh is fixedly positioned on the board, the solder paste retained by the stencil pattern is reflowed to selectively form on the underlying contacts of the printed circuit board.

Abstract: A printed circuit or hybrid circuit board with a formed solder deposit on a surface mount device (SMD) pad thereon, as well as for the formed solder deposit itself. This formed solder deposit is in a defined three-dimensional well having the proper profile and a defined solder gap. The solder before forming can be solid solder or a solder paste. By the placement of a mesh on the surface of the circuit board with the solder in place on the pads, applying a slight positive pressure on a rigid or elastic surface on the other side of the mesh or on the mesh itself, and subjecting this system to a temperature just low enough to reflow the solder by means of a heat transfer fluid, then cooling the board to solidify the solder, a product results having the above properties. The duration of the application of heat and pressure is made so brief, that the laminate structure of the board and the coating thereon remain substantially unaffected.

Abstract: The object of this invention was to construct an apparatus for forming solder deposits on a Surface Mount Device (SMD) pad on a printed circuit or hybrid board. This formed solder deposit is in a defined three-dimensional well having the proper profile and a defined solder gap. The solder before forming can be solid solder or a solder paste. By the placement of a mesh on the surface of the circuit board and the application of a slight positive pressure and tension on the mesh with vibration thereof and subjecting this system to a temperature just low enough to reflow the solder by means of a heat transfer fluid either liquid or gaseous, then cooling the board to solidify the solder, a product results having the desirable properties even when block printed. The use of this apparatus eliminates most of the problems of prior art approaches by providing uniform heating at a very short dwell time at temperature in the presence of the mesh.

Abstract: A method and apparatus for the forming of a solder deposit on an SMD pad on a printed circuit or hybrid board. This formed solder deposit is in a defined three-dimensional well having the proper profile and a defined solder gap. The solder before forming can be solid solder or a solder paste. By the placement of a mesh on the surface of the circuit board with the solder in place on the pads, applying a slight positive pressure on a rigid or elastic surface on the other side of the mesh, and subjecting this system to a temperature just low enough to reflow the solder by means of a heat transfer fluid, then cooling the board to solidify the solder, a product results having the above properties. The duration of the application of heat and pressure is made so brief, that the laminate structure of the board and the coating thereon remain substantially unaffected. A circuit board with the solder so formed thereon.