Circuit board assembly employing solder vent hole
A printed circuit board assembly employing a solder vent hole adjacent solder filled interconnect vias connecting to a conductive pallet, is disclosed. The solder vent hole allows gases to escape from an otherwise sealed cavity during solder reflow, relieving positive pressure and thereby allowing solder to flow into it. By providing an escape path for trapped air and gases generated during solder paste reflow, the out-gassing pressure and weight of the molten solder is sufficient to allow the solder paste to flow into the cavity.
1 . An electronics assembly, comprising:
a printed circuit board having a via hole therethrough and an adjacent vent hole;
a nonconductive adhesive layer having a first surface and a second surface, the first surface coupled to the printed circuit board;
a conductive substrate coupled to the adhesive layer second surface so that the adhesive layer is disposed between the printed circuit board and the substrate, wherein the adhesive layer further has a void space overlapping the via hole and the vent hole; and
reflowed solder extending into the void space, the reflowed solder connecting the printed circuit board to the substrate.
2 . The electronics assembly of claim 1 , further comprising a plurality of electronic devices mounted on the printed circuit board.
3 . The electronics assembly of claim 1 , further comprising a metalized pad plating and surrounding the via hole.
4 . The electronics assembly of claim 1 , wherein the substrate is made from an electrically conductive material and wherein the substrate provides electrical grounding for one or more of the electronic devices on the printed circuit board through the reflowed solder.
5 . The electronics assembly of claim 1 , wherein the substrate is made from a thermally conductive material and provides heat dissipation for the printed circuit board through the reflowed solder.
6 . The electronics assembly of claim 4 , wherein the substrate is made from copper.
7 . The electronics assembly of claim 5 , wherein the substrate is made from copper.
8 . The electronics assembly of claim 1 , wherein the nonconductive adhesive layer is composed of a thermal set epoxy.
9 - 13 . (canceled)
14 . An RF power amplifier circuit board assembly, comprising:
a printed circuit board having a via hole therethrough, an adjacent vent hole therethrough, and one or more RF power transistors mounted thereon;
a nonconductive adhesive layer having a first surface and a second surface, the first surface coupled to the printed circuit board;
an electrically conductive substrate coupled to the adhesive layer second surface so that the adhesive layer lies between the printed circuit board and the substrate, wherein the adhesive layer further has a void space aligned to the via hole and vent hole;
reflowed solder extending through the via hole and the void space to the substrate, the reflowed solder electrically connecting the printed circuit board to the substrate; and
one or more conductive traces on the printed circuit board electrically connecting to the reflowed solder.
15 . The RF amplifier circuit board assembly of claim 14 , further comprising a metalized pad plating and surrounding the via hole.
16 . The RF amplifier circuit board assembly of claim 14 , wherein the substrate is composed of metal and wherein the substrate provides electrical grounding and heat dissipation for the printed circuit board through the reflowed solder.
17 - 20 . (canceled)