The NTC thermistor for substrate can be embedded in substrate that do not require very accurate position accuracy when using lasers to form through holes.

The ceramic sintering body that constitutes the thermistor billet is a ceramic with negative resistance temperature characteristics. As a ceramic with negative resistance temperature characteristics, it’s able to use existing suitable ceramics for the formation of NTC thermistor, such as those ceramics of containing oxides of transition metals like Mn, Ni, Fe, Ti, Co, Al, Zn, etc. Ceramics with manganese oxide as the main component are preferably selected, which is contained more than one kind of nickel oxide, cobalt oxide, alumina, iron oxide and titanium oxide. In addition, as long as the thermistor billet has the two corresponding end surfaces, two corresponding main surfaces and two opposite side surfaces,. Its shape is not particularly limited, which can be cuboid shape, can also be cube shape. The size of two corresponding two end surfaces, two corresponding main surfaces, and two opposite side can be the same or different.

In the NTC thermistor billet, a plurality of internal electrodes are configured across the thermistor billet. On the external surface of the thermistor billet, there are two external electrodes which make electronic connection to plurality of internal electrodes. In addition, as long as the number of internal electrodes is more than one, there is no special limit. Two internal electrodes are elicited to one side of the first end surface of the thermistor billet. The other two internal electrodes are elicited to the second end surface opposite to the first end surface. The internal electrode can be formed by the coating and calcining of the conductive paste. Internal electrodes can use rare metals such as Ag, Pd, Pt and Au, or monomer of basic metals such as Cu, Ni, Al, W and Ti or their alloys.

On the external surface of the thermistor billet, two external electrodes are formed. The first external electrode has: the first electrode layer covering an end surface of the thermistor billet; The main surfaces forming on the thermistor billet, one end is connected with the first electrode layer, two second electrode layers that the other end is extending along the direction of the other end surface; The third electrode layer which is covering the first electrode layer and the second electrode layer. The second external electrode covers the first electrode layer of an end surface of the thermistor billet; The main surfaces forming on the thermistor billet, one end is connected with the first electrode layer, two second electrode layers that the other end is extending along the direction of the other end surface; The third electrode layer which is covering the first electrode layer and the second electrode layer.

To sum up, according to this method, when laser irradiating, the laser position accuracy isn’t required strictly, can use more simple process to make the NTC thermistor for substrate, and applied to the components of the built-in substrate.