Circuit board having a switch and method for fabricating the same

A circuit board having a switch, wherein the circuit board comprises:

• an insulation material layer;
• a first insulation layer on a bottom surface of the insulation material layer;
• a second insulation layer on a top surface of the insulation material layer;
• a circular channel in the first insulation layer, the insulation material layer and the second insulation layer, wherein the circular channel comprises:
• a first sub-channel extending from the first insulation layer toward the second insulation layer;
• a second sub-channel adjacent to the first sub-channel and extending from the first insulation layer toward the second insulation layer;
• a first connection channel fluidly connecting a bottom end of the first sub-channel to a bottom end of the second sub-channel;
• and
• a second connection channel fluidly connecting a top end of the first sub-channel to a top end of the second sub-channel;
• a first cover layer on a bottom surface of the first insulation layer and configured to seal an opening of the first insulation layer;
• an inert liquid material in the circular channel;
• a first conductive block in the first sub-channel, wherein a density of the inert liquid material is greater than a density of the first conductive block;
• a second conductive block in the second sub-channel, wherein a density of the inert liquid material is greater than a density of the second conductive block;
• and
• a conductive layer in the insulation material layer and adjacent to the circular channel.