**4.5 Procedures requiring more than one soldering phase**

Some prototypes, for example, RESIW or DRESIW devices [16], may need to be welded in two or more phases. To make possible a welding process divided into two or more phases, the methods described previously can be combined together. The only requirement for multiple soldering phases is to use different solder pastes with different melting temperatures, so that the following phases will not de-solder the already soldered layers in previous ones. For that, the soldering paste with the highest melting temperature will be used for the initial phase, and soldering pastes with lower melting temperatures will be used afterward when these phases contain the already welded parts of the circuit. This procedure is very useful for ridge prototypes; ridge prototypes may need different pressing covers with different geometries of each one of the pressing phases. **Figure 18** shows these press covers.

**Figure 16.** *Vias position.*

**Figure 17.** *Vias position toward edge example.*

**Figure 18.** *Press covers of an RESIW filter [14].*

*Manufacturing Methods Based on Planar Circuits DOI: http://dx.doi.org/10.5772/intechopen.109114*

**Figure 19.** *Handly backing weld prototype examples.*

This technique is also quite useful when prototype junctions are not good enough and need to be fixed manually with soldering paste and a welder. Moreover, if there was an overflow of solder paste, it can be removed with a de-soldering iron or roll out manually with a welder. These press covers are different to apply differently pressure in each soldering phase [14].
