A method for making a fine electrically conductive grid embedded in a polymer substrate. The multilayer wiring division has the first conductor layer, which includes through-hole junction pads, flatness improvement rings surrounding the through-hole junction pads and a grounding region further surrounding the flatness improvement rings. Thermal transport element makes at least partial contact with a portion of the coplanar thermal wall and with a portion of the retaining unit thereby transporting heat from the hotter thermal wall to the cooler frame of the retaining unit. One end of the at least one longitudinal port is closed by a membrane, which can be pierced through by a sharp-pointed device. In this way a text-to-speech unit selection speech synthesizer can produce more natural sounding speech with suitable stress patterns regardless of the stress of units in a unit selection database.