Load-lock apparatus and substrate cooling method

Abstract

A load-lock apparatus includes a vessel arranged to change a pressure between a pressure corresponding to the vacuum chamber and the atmospheric pressure, a pressure adjusting mechanism which adjusts a pressure in the vessel to a pressure corresponding to the vacuum chamber and the atmospheric pressure, a cooling member having a cooling mechanism and arranged in the vessel to cool a substrate by having the substrate placed on or in proximity to the cooling member, a substrate deformation detection unit for detecting deformation of the substrate in the vessel, and a controller which reduces a cooling rate of the substrate when the substrate deformation is detected during a substrate cooling period until the vessel is adjusted to have the atmospheric pressure after the vessel is adjusted to have a pressure corresponding to the vacuum chamber and a high temperature substrate is loaded into the vessel from the vacuum chamber.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a load-lock apparatus for use in a vacuum processing unit which performs a vacuum process on a target object such as a semiconductor wafer, and a substrate cooling method for use in the load-lock apparatus.BACKGROUND OF THE INVENTION[0002]In a manufacturing process of semiconductor devices, a vacuum process such as a film forming process and an etching process performed in a vacuum atmosphere is widely carried out on a semiconductor wafer serving as a target substrate. Recently, a multi-chamber type vacuum processing system has been attracted attention from viewpoints of efficiency of the vacuum process and prevention of oxidation or contamination, wherein the system has a cluster tool type structure in which vacuum processing units are connected to a transfer chamber maintained in a vacuum and a wafer is transferred to each of the vacuum processing units by a transfer unit provided in the transfer chamber (see, e.g., Japa...

AI Technical Summary

Benefits of technology

[0009]Therefore, the present invention provides a load-lock apparatus capable of cooling a substrate at a practical cooling rate while preventing deformation of the substrate to the maximum extent possible.

[0012]In the load-lock apparatus, the controller may reduce the cooling rate by stopping increasing or reducing a pressure in the vessel when the substrate deformation detection unit detects the deformation of the substrate that is equal to or larger than the predetermined value while increasing the pressure in the vessel by the pressure adjusting mechanism.

[0013]The controller may resume an increase in pressure in the vessel when the substrate deformation detection unit detects that the deformation of the substrate becomes smaller than the predetermined value after the controller reduced the cooling rate.

[0014]The load-lock apparatus may further include wafer supporting pins which are provided to be protruded from and retracted into the cooling member, receive the substrate while being protruded from the cooling member, and descend with the substrate placed thereon such that the substrate is placed on or in proximity to the cooling member. When the substrate deformation detection unit detects the deformation of the substrate that is equal to or larger than the predetermined value, the controller may reduce the cooling rate by raising the wafer supporting pins or stopping descending of the wafer supporting pins if the wafer supporting pins descend with the substrate placed thereon.

[0018]In accordance with a second aspect of the invention, there is provided a substrate cooling method for use in a load-lock apparatus for use in transferring a substrate from the atmospheric atmosphere to a vacuum chamber maintained in a vacuum and transferring a substrate having a high temperature from the vacuum chamber to the atmospheric atmosphere, the load-lock apparatus including a vessel arranged to change a pressure between a pressure corresponding to the vacuum chamber and the atmospheric pressure, a pressure adjusting mechanism which adjusts a pressure in the vessel to a pressure corresponding to the vacuum chamber when the vessel communicates with the vacuum chamber, and adjusts a pressure in the vessel to the atmospheric pressure when the vessel communicates with a space having the atmospheric atmosphere, and a cooling member having a cooling mechanism and arranged in the vessel to cool a substrate by having the substrate placed on or in proximity to the cooling member. The method may include: detecting deformation of the substrate in the vessel during a substrate cooling period until the vessel is adjusted to have the atmospheric pressure after the vessel is adjusted to have a pressure corresponding to the vacuum chamber and the substrate having the high temperature is loaded into the vessel from the vacuum chamber; and reducing a cooling rate of the substrate when the deformation of the substrate that is equal to or larger than a predetermined value is detected.

[0021]In accordance with the present invention, after a high temperature substrate is loaded into a vessel from a vacuum chamber, during a substrate cooling period until the vessel is adjusted to have the atmospheric pressure, a substrate deformation detection unit detects deformation of a substrate. When deformation of a substrate that is equal to or larger than a predetermined value is detected, cooling of the substrate is modified to restore the deformed wafer to its original state. Thus, it is possible to cool a substrate at a practical cooling rate while preventing deformation of the substrate to the maximum extent possible.

Problems solved by technology

However, when the wafer having such a high temperature is exposed to the atmosphere, the wafer is oxidized.

Further, when the wafer having such a high temperature is accommodated in a receiving vessel, there is a problem that the receiving vessel generally made of resin may be melted.

In this case, if the semiconductor wafer is cooled rapidly, the wafer may be deformed due to a difference in thermal expansion between the front and rear surface of the wafer W. Accordingly, a central or edge portion of the semiconductor wafer is separated from the cooling plate, or the central and edge portions of the semiconductor wafer have different distances to the cooling plate, thereby reducing cooling efficiency.

Hence, it is very difficult to create an optimal purge recipe for each type of films.

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