Sensor interposer employing castellated through-vias

A method of forming a sensor interposer comprising:

• provide a planar substrate;
• forming a plurality of through-vias in the planar substrate;
• cutting a portion of the planar substrate to create an interposer substrate, the cutting comprising cutting through at least four of the through-vias to create at least four castellated through-vias;
• forming a first electrical contact on the interposer substrate and electrically coupling the first electrical contact to a first castellated through-via;
• forming a second electrical contact on the interposer substrate and electrically coupling the second electrical contact to a second castellated through-via, the second castellated through-via electrically isolated from the first castellated through-via;
• and
• forming a guard trace on the interposer substrate, the guard trace electrically coupled between a third and a fourth through-via formed on the planar substrate, the guard trace isolating the first and second electrical contacts.

A wearable biosensor comprising:

• a sensor interposer comprising:
• a planar substrate;
• a first electrical contact formed on the planar substrate and electrically coupled to a first castellated through-via formed in the planar substrate;
• a second electrical contact formed on the planar substrate and electrically coupled to a second castellated through-via formed in the planar substrate, the second castellated through-via electrically isolated from the first castellated through-via;
• and
• a guard trace formed on the planar substrate, the guard trace electrically coupled between a third through-via and a fourth through-via, the third and further through-vias formed on the planar substrate, the guard trace isolating the first and second electrical contacts;
• a sensor wire physically coupled to the planar substrate, the sensor wire comprising at least two electrodes, a first electrode of the at least two electrodes electrically coupled to the first electrical contact, and a second electrode of the at least two electrodes electrically coupled to the second electrical contact;
• and
• a sensor chemical disposed on a distal end of the sensor wire;
• a printed circuit board (“PCB”) having a plurality of electrical contacts defined on a first surface of the PCB;
• and
• wherein the sensor interposer is physically coupled to the first surface of the PCB, and wherein the first, second, third, and fourth castellated through-vias are electrically and physically coupled to respective first, second, third, and fourth electrical contacts of the plurality of electrical contacts defined on the first surface of the PCB.