Aluminum nitride sintered body and semiconductor manufacturing apparatus member

#This application is based upon and claims the benefit of priority from a Japanese Patent Application No. TOKUGAN 2007-80697, filed on Mar. 27, 2007; the entire contents of which are incorporated herein by reference.

#1. Field of the Invention

#The present invention relates to an aluminum nitride sintered body that is preferable as a semiconductor manufacturing apparatus member such as heater material or electrostatic chuck material.

#Examples of the invention will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only examples and are, therefore, not to be considered limiting of the invention's scope, the examples of the invention will be described with additional specificity and detail through use of the accompanying drawings in which:

#FIG. 1 shows an X-ray diffraction profile obtained from the aluminum nitride sintered body of example 1;

#FIG. 2 shows an X-ray diffraction profile obtained from the aluminum nitride sintered body of example 3;

#In the present invention, a molar ratio of europium to aluminum content of oxide-converted content (Eu2O3/Al2O3) is preferably 0.5 or more and is more preferably 0.6 or more. As a result, Eu3Al2O6 which is a conducting phase can be efficiently generated at the grain boundary phase of the aluminum nitride sintered body. Here, Eu3Al2O6 is the europium-aluminum oxide which has an X-ray diffraction profile having a peak substantially the same as that of an Sr3Al2O6 phase. The upper limit of (Eu2O3/Al2O3) is preferably 3.0 or less. The reason is that (Eu2O3/Al2O3) exceeding this limit causes excessive Eu2O3 in the entirety to cause Eu2O3 unreacted with Al2O3 to remain in the aluminum nitride sintered body, causing a risk of an adverse impact on the thermal conductivity.

#Here, the molar ratio of the oxide-converted content of europium to the alumina content (Eu2O3/Al2O3) was calculated in the manner as described below. First, the Eu2O3 content is calculated as Eu2O3 based on a chemical analysis value of an europium amount included in the aluminum nitride sintered body. It is assumed that the remaining oxygen obtained by deducting an Eu2O3-retaining oxygen amount from the total oxygen amount in the sintered body exists in the form of Al2O3 to calculate the Al2O3 content. The ratio of them was calculated to calculate (Eu2O3/Al2O3). However, a part of europium contained in the material of the present invention is considered as being divalent.

#In the present invention, preferably, the europium-aluminum oxide phase has a formation of the network microstructure. Specifically, the europium-aluminum oxide phase is continuously existed so as to surround the aluminum nitride grains to generate a network microstructure. Although the average grain diameter of the aluminum nitride is not limited, the average grain diameter is preferably 3 μm or more from the viewpoint of the thermal conductivity. Since an increased aluminum nitride grain diameter may cause a risk of a reduced strength, the average grain diameter is preferably 20 μm or less.