| 摘要 |
A ceramic heater composed of a ceramic substrate and a resistant heating element embedded within the ceramic substrate along a predetermined planar pattern is obtained by holding a convolution of a spiral-coiled high melting metallic filament in the above predetermined planar pattern and heat-treating the convolution at a temperature not higher than a primary recrystallization commencement temperature of the high melting metal under a non-oxidative atmosphere to provide the resistant heating element, embedding the resulting resistant heating element within a ceramic shaped body, and then, sintering the ceramic shaped body. In a preferred embodiment, the resistant heating element is a convolution of a spiral coil, the number of coils per a unit length of said convolution is set at a predetermined value in each of defined domains of the ceramic heater, and when the number of coils per a unit length of the convolution is determined, the relation of the maximal value, the minimal value and the mean value, of all the determined numbers of coils in the above domains, satisfies the formula:(maximal value-minimal value)/mean value</=0.1.Another preferred embodiment comprising a disc-shaped ceramic substrate and a resistant heating element embedded within the substrate is adapted for application in semiconductor wafer heating, wherein a resistant heating element having a planar shape composed of a plurality of concentric loops differing in diameters from each other and connecting portions which connect inner loops in sequence with outer loops to form a series of resistant heating element. In a process for manufacturing ceramic articles composed of a ceramic substrate, an electroconducting body embedded within the ceramic substrate and a conduit or pit bored avoiding the above electroconducting body in the ceramic substrate, an X-ray transmission photograph of the ceramic substrate is taken and then the conduit or pit is formed based on the X-ray transmission photograph.
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