1 SUBSTRATE PROCESSING APPARATUS AND SUBSTRATE PROCESSING METHOD
The present invention relates to a substrate processing apparatus and a substrate processing method for processing a surface of a substrate to be processed such as a semiconductor wafer.
In manufacturing steps of a semiconductor device, there is a possibility that particles adhere to a surface of a semiconductor wafer (hereinafter also referred to simply as “wafer”), during a film-deposition process and an etching process for the wafer, for example. Thus, it is necessary to clean the surface of the wafer.
As a wafer cleaning apparatus for cleaning a wafer, there has been known an apparatus that cleans a wafer, by supplying a cleaning liquid of a deionized water or a chemical liquid onto a surface of the wafer which is being rotated by a spin chuck, then rinsing the wafer, and finally rotating the wafer at a high speed to dry the same.
There is a case in which a cleaning liquid containing hydrofluoro ether (hereinafter also referred to simply as “HFE”) is used as a cleaning liquid to be supplied to the wafer (see, IP2005-5469A, IP2006-41065A, and JP2002124504A). As compared with a conventional cleaning liquid of, e.g., a deionized water, a surface tension and a viscosity of the cleaning liquid containing HFE are significantly lowered. Thus, the cleaning liquid containing HFE is capable of easily entering small recesses in a surface of a wafer, so that a slight amount of particles resting in the small recesses can be favorably removed. Further, a specific gravity of HFE is about 1.5, which is greater than a specific gravity of water. Thus, when HFE is supplied onto a surface of a wafer, the HFE collides with the wafer with a greater kinetic energy. As a result, a processing efliciency of the wafer can be enhanced. Furthermore, since HFE does not have a flash point, there is no possibility that HFE catches fire during a process of the wafer.
DISCLOSURE OF THE INVENTION
However, since HFE is a highly volatile liquid, when a cleaning liquid containing HFE is supplied to a wafer, a heat of the wafer is taken away by evaporation of the HFE, and thus a temperature of the wafer is rapidly lowered. When the temperature of the wafer is rapidly lowered, the water vapor in an atmosphere surrounding the wafer is cooled to become water droplets, and these water droplets may adhere to a surface of the wafer. The water droplets adhering to the surface of the wafer during a cleaning process of the wafer invites problems such as formation of a watermark on the surface of the wafer and corrosion of a copper wiring exposed to the surface of the wafer.
The present invention has been made in view of these circumstances. The object of the present invention is to provide a substrate processing apparatus and a substrate processing method capable of preventing, when a substrate to be processed such as a semiconductor wafer is cleaned by a cleaning liquid containing hydrofluoro ether, formation of a watermark on a surface of the substrate to be processed and corrosion of a copper wiring exposed to the surface of the wafer.
The present invention is a substrate processing apparatus comprising: a chamber; a substrate holding mechanism dis
posed in the chamber, for holding a substrate to be processed; a cleaning-liquid supply unit that supplies a cleaning liquid containing hydrofluoro ether onto a substrate to be processed held by the substrate holding mechanism; and a gas supply unit that supplies a gas into the chamber, the gas being configured to prevent moisture from being adhered to a substrate to be processed when a cleaning liquid containing hydrofluoro ether is supplied onto the substrate to be processed.
In addition, the present invention is a substrate processing method comprising the steps of: filling a chamber with a gas, the gas being configured to prevent moisture from being adhered to a substrate to be processed when a cleaning liquid containing hydrofluoro ether is supplied onto the substrate to be processed; and supplying a cleaning liquid containing hydrofluoro ether onto a substrate to be processed placed in the chamber that is filled with the gas.
Since hydrofluoro ether is highly volatile, when the cleaning liquid containing hydrofluoro ether is supplied to the substrate to be processed, a heat of the substrate to be processed is taken away by evaporation of the cleaning liquid so that a temperature of the substrate to be processed is lowered. However, according to the above-described substrate processing apparatus and the substrate processing method, the chamber is filled with the gas which is configured to prevent moisture from being adhered to the substrate to be processed when the cleaning liquid containing hydrofluoro ether is supplied onto the substrate to be processed. Thus, even when the temperature of the substrate to be processed is lowered, there is no possibility that moisture is adhered to the substrate to be processed. Therefore, when the substrate to be processed is cleaned by the cleaning liquid containing hydrofluoro ether, it is possible to prevent formation of a watermark on a surface of the substrate to be processed and corrosion of a copper wiring exposed to the surface of the wafer.
In the above-described substrate processing apparatus, it is preferable that the substrate processing apparatus further comprises a control unit that controls the cleaning-liquid supply unit and the gas supply unit such that the gas is previously supplied from the gas supply unit into the chamber to fill the chamber with the gas, when the cleaning liquid containing hydrofluoro ether is supplied from the cleaning-liquid supply unit onto the substrate to be processed held by the substrate holding mechanism. In this case, when the cleaning liquid containing hydrofluoro ether is supplied onto the substrate to be processed, the above specific gas can be reliably filled in the chamber.
In the above-described substrate processing apparatus and the substrate processing method, it is preferable that the gas is a nitrogen gas or an air having a humidity lower than a humidity of an atmospheric air outside the chamber. In this case, even when a temperature of the substrate to be processed is lowered by supplying the cleaning liquid containing hydrofluoro ether onto the substrate to be processed, an amount of moisture to be adhered to the substrate to be processed can be decreased because of the lower humidity of the nitrogen gas or the air in the chamber than a humidity of the atmospheric air.
In the above-described substrate processing apparatus and the substrate processing method, it is preferable that the gas is a nitrogen gas or an air having a temperature lower than a temperature of an atmospheric air outside the chamber. In this case, since the temperature in the camber is previously lowered, when the cleaning liquid containing hydrofluoro ether is supplied to the substrate to be processed, a temperature of the substrate to be processed is diflicult to be lowered, so that moisture in the gas in the chamber is prevented from being adhered to the substrate to be processed.
