Ngk Insulators, Inc.

Reo Watanabe

Yutaka Unno

Seiya Inoue

Yuma Iwata

Kazuhiro Nobori

Takuji Kimura

Nobuyuki Kondou

A wafer placement table includes a ceramic plate, an electrode embedded in the ceramic plate, a hollow ceramic shaft attached to a surface of the ceramic plate, a power-supplying member running inside the ceramic shaft and connected to a terminal of the electrode, a plate-side attaching site defined on the ceramic plate and to which the power-supplying member is attached, a power-source-side attaching site defined at a free end of the ceramic shaft and to which the power-supplying member is attached, and a redirecting member provided inside the ceramic shaft. The power-source-side attaching site is defined in correspondence with the plate-side attaching site and in such a manner as to be shifted from the plate-side attaching site in plan view. The redirecting member holds the power-supplying member such that the power-supplying member extending from the power-source-side attaching site is forcibly redirected toward the plate-side attaching site.

Wafer placement table

A wafer placement table includes a ceramic plate, an electrode embedded in the ceramic plate, a hollow ceramic shaft attached to a surface of the ceramic plate, a power-supplying member running inside the ceramic shaft and connected to a terminal of the electrode, a plate-side attaching site defined on the ceramic plate and to which the power-supplying member is attached, and a power-source-side attaching site defined at a free end of the ceramic shaft and to which the power-supplying member is attached. The power-source-side attaching site is defined in correspondence with the plate-side attaching site and in such a manner as to be shifted from the plate-side attaching site in plan view. The power-supplying member includes a redirecting portion where the power-supplying member extending from the power-source-side attaching site is forcibly redirected toward the plate-side attaching site.

An electrostatic-chuck heater is of a Johnsen-Rahbek type and is used in a process of forming a conductive film on a wafer. The electrostatic-chuck heater includes a disc-shaped ceramic base including an electrostatic electrode and a heating resistor, and a hollow shaft attached to a side of the ceramic base that is opposite a side having a wafer-mounting surface. A through-hole extends in a peripheral wall of the hollow shaft from a lower end through to an area of the wafer-mounting surface that is on an inner side with respect to a circular groove. The through-hole allows gas to be supplied from the lower end of the hollow shaft into a below-wafer space enclosed by the wafer-mounting surface, an outermost projection group, and the wafer mounted on the wafer-mounting surface.

Electrostatic-chuck heater

An electrostatic-chuck heater is a Johnsen-Rahbek electrostatic-chuck heater and is used in a process of forming a conductive film on a wafer. The electrostatic-chuck heater includes a disc-shaped ceramic base including an electrostatic electrode and a heating resistor, and a hollow shaft attached to a side of the ceramic base that is opposite a wafer-mounting surface. A protruding ring is provided on the wafer-mounting surface and having an outside diameter smaller than a diameter of the wafer. A through-hole extends in a peripheral wall of the hollow shaft from a lower end through to an area of the wafer-mounting surface that is on an inner side with respect to the protruding ring. The through-hole allows gas to be supplied from the lower end of the hollow shaft into a below-wafer space enclosed by the wafer-mounting surface, the protruding ring, and the wafer mounted on the wafer-mounting surface.

An electrostatic chuck has a structure in which an electrostatic electrode is embedded in a disk-like ceramic plate and attracts a wafer that is placed on the ceramic plate and that has a diameter smaller than that of the ceramic plate by Johnsen-Rahbek force. The electrostatic chuck includes an insulating film that has an electric resistance larger than that of the ceramic plate in an annular region of a front surface of the ceramic plate from an outer circumferential edge of the ceramic plate to the inside of an outer circumferential edge of the wafer that is placed on the ceramic plate.

Electrostatic chuck having an annular outer region covered by an insulating film

The electrostatic chuck includes a discoidal alumina ceramic substrate and a heater electrode and an electrostatic electrode embedded in the alumina ceramic substrate. The top surface of the alumina ceramic substrate is a wafer-mounting face. The heater electrode has a pattern, for example, of a single continuous line so as to realize electric wiring over the entire surface of the alumina ceramic substrate. Upon the application of a voltage, the heater electrode generates heat and heats the wafer W. The heater electrode is made of a complex oxide of titanium, aluminum, and magnesium (Ti&#x2014;Al&#x2014;Mg&#x2014;O) dispersed in molybdenum.

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Handa, Japan

Reo Watanabe