Multilayer resin substrate, and method of manufacturing multilayer resin substrate

A multilayer resin substrate comprising:

• a plurality of resin substrates that are laminated together;
• an overlapping portion in which a signal line that is provided as a conductor pattern and another conductor pattern overlap each other in a laminating direction of the plurality of resin substrates;
• a non-overlapping portion in which the signal line and the another conductor pattern do not overlap each other in the laminating direction of the plurality of resin substrates;
• and
• a thin portion that is provided in the non-overlapping portion near the overlapping portion, the thin portion being a portion of the multilayer resin substrate which has a thickness smaller than a thickness of the plurality of resin substrates in the overlapping portion in the laminating direction of the plurality of resin substrates;
• wherein
• the thin portion, in plan view in the laminating direction of the plurality of resin substrates, does not overlap the overlapping portion, and is defined by a plurality of recesses disposed along a direction in which the signal line extends or is defined by a plurality of recesses that extend continuously in the direction in which the signal line extends;
• the thin portion is provided in only the plurality of resin substrates;
• the plurality of recesses are provided in a top resin substrate or a bottom resin substrate of the plurality of resin substrates;
• and
• the signal line and the another conductor pattern are not electrically connected to one another.