Electronic devices for high temperature drilling operations
The present disclosure provides the printed circuit board assembly suitable for operating downhole at high temperatures. The printed circuit board assembly has a ceramic circuit board with a plurality of chips installed on it. At least one of the chips has an aluminum nitride or a silicon nitride substrate. In some of the chips, aluminum nitride is used as the oxide layer in a Si-on-Insulator configuration. In other chips, integrated circuits are fabricated on a substrate made from aluminum nitride, silicon nitride, silicon carbide, or sapphire.
1. A drilling system, comprising:
a drilling assembly comprising a drill bit and a drill collar;
a drill string; and
a printed circuit board assembly installed in the drill collar,
wherein the printed circuit board assembly comprises a plurality of chips installed on a printed circuit board, at least one of the chips comprises an integrated circuit fabricated on a silicon nitride substrate, at least one of the chips is a silicon-on-insulator chip having a silicon carbide substrate, at least one wireless transmitter, and at least one wireless receivers, and a sensor circuit coupled with a plurality of sensors for sensing one or more conditions of the drilling bit or the drill string and properties of an earth formation surrounding the drill bit or the drill string, wherein the at least one wireless transmitter is disposed on the printed circuit board assembly; and
a telemetry unit disposed on the printed circuit board assembly coupled with the sensor circuit, wherein the telemetry unit receives a sensor signal from at least one of the plurality of sensors and transmits the sensor signal to a surface location via the at least one wireless transmitter,
wherein the printed circuit board is made from a polyimide prepreg.
2. The drilling system of claim 1 , wherein at least one of the plurality of chips is a multi-chip module.
3. The drilling system of claim 1 , wherein at least one of the plurality of the chips is a hermetically sealed chip.
4. The drilling system of claim 1 , wherein the printed circuit board assembly is operable at a temperature of 175° C.
5. The drilling system of claim 1 , wherein all of the plurality of chips on the printed circuit board are encapsulated using silicon nitride or silicon oxynitride.
6. The drilling system of claim 1 , wherein all of the plurality of chips on the printed circuit board are hermetically sealed.