A semiconductor integrated circuit in which a band-pass filter, a sound detector, and some other circuits are formed on a single semiconductor substrate. This task is complicated by the fact that microreflections in the upstream channels cause intersymbol interference, which tends to bias the frequency estimation circuit. The first electrostrictive material is positioned between the first and intermediate electrode layers. The method further includes applying spatially varying amounts of heat to the assembly across its lateral extent to soften the thermoplastic adhesive layer in the bonding areas relatively uniformly across the lateral extent of the assembly compared to applying a non-spatially varying amount of heat across the lateral extent of the assembly.