With the advent of the era of integration of various electronic devices, electronic equipment has put forward higher requirements for circuit miniaturization, high density, multifunctionality, high reliability, high speed and high power. Because co-fired multilayer ceramic substrates can meet many requirements of electronic equipment for circuits, they have been widely used in recent years. Co-fired multilayer ceramic substrates can be divided into high temperature co-fired multilayer ceramic (HTCC) substrates and low temperature co-fired multilayer ceramic (LTCC) substrates. Compared with low temperature co-fired ceramics, high temperature co-fired ceramics have the advantages of high mechanical strength, high wiring density, stable chemical properties, high heat dissipation coefficient and low material cost. They have been more widely used in the heating and packaging fields with higher thermal stability requirements, lower high temperature volatile gas requirements and higher sealing requirements. HTCC ceramic heating sheets are mainly used to replace the most widely used alloy wire heating elements and PTC heating elements and their components. Alloy wire heating elements have disadvantages such as easy oxidation at high temperatures, short life, unsafe with open flames, low thermal efficiency, and uneven heating. The heating temperature of PTC heating elements is generally only around 200°C, and those with heating temperatures above 120°C generally use lead tetroxide, which is a product that is being eliminated due to its high lead content.
