PURPOSE: To grind a thin plate material very thin and moreover, to satisfy a flatness, a parallelism, a surface roughness or the like, which is required for the material, by a method wherein the material id directly bonded on a substrate, the non-bonded surface of the directly bonded material is ground and the material is taken out from the substrate and the material, which are bonded together.
CONSTITUTION: As the material 1 for a piezoelectric material is directly bonded on a thick substrate 2 having no deflection, a grinding of the material 1 using a thick carrier becomes possible and the material 1 bonded directly on the substrate 2 can be formed into an ultrathin plate by grinding to a certain degree. When a direct bonding method is used, the generation of an irregularity or the like in the thickness of the material 1 subsequent to the grinding due to the use of a bonding agent, which is the mooted point of a single-sided polishing method, is eliminated because the thickness of the bonding part is substantially zero and it is also not generated that flatness, parallelism or surface roughness, which is required for a thin plate material, is reduced. Accordingly, the thickness of the material 1 can be ground in a thickness of 10μm or thinner, for example, and moreover, the requirement of a device can be satisfied.
KANAHOSHI AKIHIRO
TOMITA YOSHIHIRO
EDA KAZUO
