Micro-electromechanical systems pump

A micro-electromechanical systems pump, comprising:

• a first substrate having a plurality of inlets, wherein each of the plurality of inlets is a conical hole;
• a first oxide layer stacked on the first substrate, wherein the first oxide layer has a plurality of converging channels and a converging chamber, wherein the plurality of converging channels is in communication between the converging chamber and the plurality of inlets;
• a second substrate combined with the first substrate, comprising:
• a silicon wafer layer, having:
• an actuation portion being circular and having a maximum stress value and an actuation stress value;
• an outer peripheral portion being in a hollow ring shape and surrounding the periphery of the actuation portion;
• a plurality of connection portions respectively connected between the actuation portion and the outer peripheral portion;
• and
• a plurality of fluid channels surrounding the periphery of the actuation portion and located between the plurality of connection portions;
• a second oxide layer formed on the silicon wafer layer, wherein the second oxide layer is in a hollow ring shape, and the second oxide layer and the silicon wafer layer together define a vibration chamber;
• a silicon material layer being in a circular shape and located at the second oxide layer, wherein the silicon material layer is combined with the first oxide layer, and the silicon material layer has:
• a perforation located in a center portion of the silicon material layer;
• a vibration portion located in a peripheral area of the perforation;
• and
• a fixed portion located in a peripheral area of the silicon material layer;
• and
• a piezoelectric element being in a circular shape and stacked on the actuation portion of the silicon wafer layer, wherein the piezoelectric element has a piezoelectric stress value, wherein a ratio between an area of the plurality of connection portions and an area of the plurality of fluid channels ranges from 0.7:1 to 2.7:1;
• wherein the maximum stress value is greater than the actuation stress value, and the actuation stress value is greater than the piezoelectric stress value.