BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a substrate processing device and a substrate processing method for supplying a processing liquid to a substrate to carry out a chemical treatment such as etching while rotating the substrate. The substrate to be processed includes substrates, for example, a semiconductor wafer, a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a substrate for a solar cell, and the like.

Description of the Background Art

Although a series of processing steps for a substrate such as a semiconductor wafer have a plurality of film forming steps for forming a thin film of a metal, a photoresist or the like on a front surface (“an upper surface”) of the substrate, a film is also formed on a back surface (“a lower surface”) of the substrate or a peripheral edge part of the upper surface of the substrate at the film forming step in some cases. In general, however, the film formation is required for only a circuit formation region in a central part of the upper surface of the substrate in the substrate. In cases where the film is formed on the back surface of the substrate or the peripheral edge part of the upper surface of the substrate, a thin film formed on the peripheral edge part of the upper surface of the substrate may be peeled by contact with another device at a subsequent step to the film forming step, and may cause reduction in yield or a trouble of a substrate processing device itself.

Therefore, there is proposed a substrate processing device for carrying out so-called bevel etching, that is, previously supplying a processing liquid having its temperature controlled to a peripheral edge part of a substrate held in a substantially horizontal condition while rotating the substrate, thereby removing a thin film formed on the peripheral edge part of a upper surface of the substrate.

For example, the substrate processing device described in Japanese Patent Application Laid-Open No. 2004-6672 serves to supply the etchant from the nozzle taking an opposed shape to the central part in the lower surface of the substrate held in a substantially horizontal condition to the lower surface of the substrate while rotating the substrate, and to cause the etchant spreading toward the peripheral edge part by the action of centrifugal force to go around the peripheral edge part of the upper surface of the substrate, thereby etching the peripheral edge part of the upper surface of the substrate.

Moreover, the substrate processing device described in Japanese Patent Application Laid-Open No. 2008-47629 has the blocking member which is opposed to the upper surface of the substrate above the substrate and serves to supply the processing liquid from the nozzle disposed on the peripheral edge part of the blocking member toward the peripheral edge part of the upper surface of the substrate while rotating the substrate in the substantially horizontal plane, thereby etching the peripheral edge part of the upper surface of the substrate.

However, the devices disclosed in Japanese Patent Application Laid-Open Nos. 2004-6672 and 2008-47629 have a problem in that the amount of the processing liquid and the processing time which are required for the etching in the peripheral edge part are increased because the temperature of the peripheral edge part is reduced due to the rotation of the substrate, resulting in decrease in the etching rate.

In the technique of this type, it is demanded to reduce an etching width in the peripheral edge part (“end”) of the upper surface of the substrate as small and evenly as possible in order to effectively utilize, as a device, an area over the substrate which is as large as possible. In the technical field of manufacture of a semiconductor device, particularly, it is desired to decrease an etching width of 2 to 3 mm in the related art down to 1 mm or less in order to reduce a loss in a peripheral edge part of a wafer which is increased with increase in diameter of a semiconductor wafer, for example.

As a method for reducing the etching width by the substrate processing device described in the Japanese Patent Application Laid-Open No. 2004-6672, it is supposed to decrease an amount of supply of the processing liquid and to increase the rotating speed of the substrate in order to reduce an amount of wraparound of the processing liquid toward the upper surface of the substrate. According to the method, although an average etching width can be reduced, uniformity of the etching width is deteriorated, for example, the amount of wraparound of the processing liquid to the peripheral edge part is controlled with difficulty so that a portion to be etched locally and greatly appears. Furthermore, there is also a problem in that the temperatures of the peripheral edge part and the processing liquid in the peripheral edge part are lowered, resulting in reduction in an etching rate.

In order to decrease the etching width by the substrate processing device described in the Japanese Patent Application Laid-Open No. 2008-47629, it is necessary to decrease the amount of supply of the processing liquid to be supplied to the peripheral edge part of the substrate. However, there is a problem in that the etching rate in the peripheral edge part of the substrate is reduced due to decrease in the amount of the processing liquid and reduction in the temperature of the processing liquid in a pipe due to the decrease.

These are problems which are not limited to the etching using an etchant, but are caused in general processing for carrying out a chemical treatment for a substrate by using a processing liquid having a chemical activity (chemical reactivity) varied depending on a temperature (a processing liquid having a reaction rate increased with a rise in temperature).

SUMMARY OF THE INVENTION

The present invention is directed to a substrate processing device for carrying out a chemical treatment for a substrate by using a processing liquid having a chemical activity varied depending on a temperature (a processing liquid having a reaction rate increased with a rise in temperature).

According to an aspect of the present invention, the substrate processing device includes a substrate holding portion for holding a substrate in a substantially horizontal posture; a rotating portion for rotating the substrate held in the substrate holding portion in a substantially horizontal plane; a heating portion for injecting heating steam to a peripheral edge part of the substrate to heat the peripheral edge part; a peripheral edge processing portion for supplying a processing liquid from above to the peripheral edge part heated by the heating portion, thereby carrying out a chemical treatment for the peripheral edge part; and a gas injecting portion for injecting a gas from above the substrate toward a predetermined injection target region defined within a range surrounded by a rotating track of the peripheral edge part of the substrate in an upper surface of the substrate, to generate, on the substrate, a gas flow which flows from the injection target region toward the peripheral edge part of the substrate.

The processing liquid is supplied to the peripheral edge part of the substrate heated by injecting the heating steam so that the chemical treatment for the peripheral edge part is carried out. Accordingly, it is possible to suppress reduction in a temperature of the peripheral edge part of the substrate by the rotation. Consequently, a change in the chemical activity of the processing liquid is also reduced and an amount of consumption of the processing liquid and a time required for processing are suppressed. The gas is injected from above the substrate toward the predetermined injection target region defined within the range surrounded by the rotating track of the peripheral edge part of the substrate in the upper surface of the substrate, to generate, on the substrate, a gas flow which flows from the injection target region toward the peripheral edge part of the substrate. Consequently, it is possible to prevent mist obtained by condensation of the steam or a mist-like processing liquid from adhering onto a non-processed region of the upper surface of the substrate. Therefore, it is possible to supply a sufficient amount of steam for heating the peripheral edge part of the substrate while suppressing deterioration in the non-processed region due to the adhering of the mist.

Preferably, the substrate processing device further includes a lower surface processing portion for supplying a processing liquid to a lower surface of the substrate, thereby carrying out a chemical treatment for the lower surface, the lower surface processing portion including an opposed surface which is opposed to a substantially entire region of the lower surface of the substrate which is rotated by the rotating portion and a processing liquid discharging port formed on the opposed surface, and discharging the processing liquid from the processing liquid discharging portion to bring a space between the lower surface of the substrate and the opposed surface to a fluid-tight condition with the processing liquid.

The processing liquid is discharged from the processing liquid discharging port of the lower surface processing portion including the opposed surface which is opposed to the substantially entire region of the lower surface of the substrate to be rotated so that the space between the lower surface of the substrate and the opposed surface is brought to the fluid-tight condition with the processing liquid. Therefore, even if the substrate is rotated at a low speed, the processing liquid can be supplied to the entire region of the lower surface of the substrate. Consequently, it is possible to carry out the chemical treatment for the peripheral edge part and the lower surface in the substrate while suppressing a drop in the temperature of the peripheral edge part of the substrate, thereby reducing energy required for heating the peripheral edge part. Moreover, it is possible to suppress wraparound of the processing liquid from the lower surface of the substrate to the peripheral edge part of the upper surface of the substrate by reducing the rotating speed of the substrate. Thus, it is easy to control the processing width of the peripheral edge part.

According to another aspect of the present invention, the substrate processing device includes a substrate holding portion for holding a substrate in a substantially horizontal posture; a rotating portion for rotating the substrate held in the substrate holding portion in a substantially horizontal plane; a plurality of heating portions disposed to be opposed to a plurality of different positions in a rotating track of a peripheral edge part of the substrate respectively and heating the peripheral edge part in the positions respectively; and a peripheral edge processing portion for supplying the processing liquid from above to the peripheral edge part heated by the plurality of heating portions, thereby carrying out a chemical treatment for the peripheral edge part.

The peripheral edge part is heated in the plurality of different positions in the rotating track of the peripheral edge part of the substrate respectively and the processing liquid is supplied to the peripheral edge part from above. Therefore, even in the case where the heating width in the radial direction in the peripheral edge part is small, the temperature of the peripheral edge part can be prevented from being reduced. Even if the amount of the processing liquid is small, it is possible to enhance reactivity of the processing liquid by suppressing reduction in a reaction rate of the processing liquid in the region having a small width which is heated by the heating portion in the peripheral edge part of the upper surface of the substrate. Accordingly, it is possible to reduce the chemical treating width while suppressing deterioration in each of uniformity of the chemical processing width and processing efficiency.

The present invention is also directed to a substrate processing method for carrying out a chemical treatment for a substrate by using a processing liquid having a chemical activity varied depending on a temperature (a processing liquid having a reaction rate increased with a rise in temperature).

According to an aspect of the present invention, a substrate processing method includes a rotating step of holding a substrate in a substantially horizontal posture to rotate the substrate in a substantially horizontal plane; a heating step of injecting heating steam to a peripheral edge part of the substrate to heat the peripheral edge part in parallel with the rotating step; a peripheral edge processing step of supplying a processing liquid from above to the peripheral edge part which is heated in the heating step, thereby carrying out a chemical treatment for the peripheral edge part; and a gas injecting step of injecting a gas from above the substrate toward a predetermined injection target region defined within a range surrounded by a rotating track of the peripheral edge part of the substrate in an upper surface of the substrate, to generate, on the substrate, a gas flow which flows from the injection target region toward the peripheral edge part of the substrate in parallel with the heating step and the peripheral edge processing step.

According to another aspect of the present invention, the substrate processing method includes a rotating step of holding a substrate in a substantially horizontal posture to rotate the substrate in a substantially horizontal plane; a heating step of heating a peripheral edge part of the substrate in a plurality of different positions in a rotating track of the peripheral edge part respectively in parallel with the rotating step; and a peripheral edge processing step of supplying a processing liquid from above to the peripheral edge part which is heated in the heating step, thereby carrying out a chemical treatment for the peripheral edge part.

Therefore, it is an object of the present invention to provide a technique capable of suppressing an amount of consumption of a processing liquid and a time required for processing. Moreover, it is another object of the present invention to provide a technique capable of reducing a chemical treating width (an etching width or the like) while suppressing deterioration in each of uniformity of the chemical treating width and chemical treating efficiency (an etching rate or the like).

These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

