Composite ceramic body, and component member for semiconductor manufacturing apparatus
A composite ceramic body which includes three phases consisting of a MgO phase, a YAP (YAlO 3 ) phase and a spinel (MgAl 2 O 4 ) phase. This composite ceramic body has a plasma resistance greater than that of alumina and approximately equal to that of MgO. Mechanical properties, such as hardness and bending strength, of the composite ceramic body, are approximately equal or superior to those of Al 2 O 3 . A raw material cost and a manufacturing cost thereof are lower than those of a rare-earth oxide. Further, electric conductive particles may be added thereto to lower an electrical resistivity. The composite ceramic body is suitably usable as component parts for a semiconductor manufacturing equipment.
1. A composite ceramic body comprising three phases comprising a MgO phase, a YAP phase and a MgAl 2 O 4 phase, with at least one of:
the MgO phase comprising at least 10 (volume %), and
the MgAl 2 O 4 phase comprising less than 79.2 (volume %).
2. The composite ceramic body as defined in claim 1 , wherein, on an assumption that a volume percent of the YAP phase and a volume percent of the MgAl 2 O 4 phase are represented, respectively, by S YAP (volume %) and S MgAl (volume %), the S YAP and the S MgAl satisfy the following relationship:
S YAP /( S YAP +S MgAl )≦0.69.
3. The composite ceramic body as defined in claim 2 , wherein, on an assumption that a volume percent of the MgO phase is represented by S MgO (volume %), the S MgO , the S YAP and the S MgAl satisfy the following relationships:
when S MgO G≧ 60(volume %),
S YAP ≧1(volume %) and S MgAl ≧1(volume %); and
when 10≦ S MgO <60(volume %),
S YAP ≧10.5(volume %).
4. The composite ceramic body as defined in claim 1 , which further comprises, as a fourth phase, 0.01 to 50 volume % of a phase of electrical conductive substance.
5. The composite ceramic body as defined in claim 4 , wherein the electrical conductive substance is one or more, or a solid solution of two or more, selected from the group consisting of graphite, titanium carbide, titanium nitride, tungsten carbide, tungsten nitride, molybdenum carbide, molybdenum nitride, zirconium carbide, zirconium nitride, zirconium boride, zirconium silicide, and carbon nanotube.
6. Component parts for a semiconductor manufacturing equipment, comprising the composite ceramic body as defined in claim 1 .
7. The composite ceramic body as defined in claim 1 , the MgO phase comprising at least 10 (volume %).
8. The composite ceramic body as defined in claim 1 , the MgAl 2 O 4 phase comprising less than 79.2 (volume %).