JPS62173718A - Cleaning method for semiconductor wafer - Google Patents

Abstract

PURPOSE:To prevent the generation of the damage of a semiconductor wafer by ejecting cleaning fluid while a nozzle of cleaning fluid is moved slowly in the upper section of the peripheral section of the rotating semiconductor wafer and shifted fast in the central section of revolution. CONSTITUTION:A semiconductor wafer 11 is rotated at constant speed by a chuck 10. A pulse signal having predetermined device characteristics is transmit ted over a stepping motor 15, and a cleaning fluid such as high-pressure water 13 or the like is sprayed against the surface of the wafer 1 while a nozzle 14 of cleaning fluid is moved slowly in the peripheral section of the wafer 11 and shifted fast with an approach to the central section of the revolution of the wafer. Consequently, the cleaning fluid in uniforms quantity is sprayed against the whole surface of the wafer 11. Accordingly, the generation of the damage of the wafer 1 is prevented.

Description

[Detailed description of the invention] Purpose of invention] (Industrial application field) The present invention relates to a method for cleaning semiconductor wafers.

(Prior Art) Conventionally, semiconductor wafers have been cleaned using a cleaning device as shown in FIG. 4 in order to remove dust and impurities adhering to the surfaces of semiconductor wafers. In the figure, reference numeral 1 denotes a chuck for fixing a semiconductor wafer 2 as an object to be processed. The chuck 1 is rotated at a constant speed by a motor 3 connected directly below it. A cleaning liquid nozzle 4 that spouts high-pressure water as a cleaning liquid is provided above the chuck 1 so as to reciprocate across the top of the semiconductor wafer 2. The reciprocating movement of the cleaning liquid nozzle 4 is performed by a constant speed rotating motor 5 shown in FIG. 5 or a cylinder (not shown).

(Problems to be Solved by the Invention) However, in the conventional method, as shown in FIG.
The moving speed of is set constant. Therefore, since the peripheral speed of the rotating semiconductor wafer 2 is higher at the periphery than at the center, the cleaning liquid nozzle 4 faces the wafer for a longer period of time near point B at the center than at the periphery. . As a result, the high-pressure water hits the center of the semiconductor wafer 2 for a longer time than other areas, making it more likely to be damaged. Further, there was a problem in that it was not possible to stably and uniformly perform a cleaning treatment on the entire surface of the semiconductor wafer 2.

Structure of the Invention (Means for Solving Problems) The present invention comprises a process of rotating a semiconductor wafer at a predetermined speed, and a process of rotating a semiconductor wafer from the outside of the semiconductor wafer with a trajectory passing through the center of rotation. A step of spraying the cleaning liquid from the cleaning liquid nozzle onto the surface of the semiconductor wafer, which is the surface to be cleaned, while moving the cleaning liquid nozzle to face the surface of the semiconductor wafer, which is the surface to be cleaned, at a slow moving speed and a high moving speed at the center. This is a method for cleaning semiconductor wafers.

Here, as a means for driving the cleaning liquid nozzle at a variable speed, any means such as a means for changing the supply/cell number using a stepping motor may be used. In short, it is sufficient that the cleaning liquid nozzle is moved at a slow speed when the circumferential speed of the rotating semiconductor wafer is high, and at a high speed when the circumferential speed is low.

The cleaning liquid sprayed from the cleaning liquid nozzle is preferably selected as appropriate, such as high-pressure water or organic solvent, depending on the type of garbage to be cleaned.

(Function) According to the semiconductor wafer cleaning method of the present invention, the cleaning liquid nozzle is moved slowly above the periphery of the rotating semiconductor wafer and moved quickly above the rotating center while ejecting the cleaning liquid. The cleaning liquid can be sprayed evenly over the entire surface. As a result, it is possible to prevent damage to the semiconductor wafer and to stably perform an effective cleaning process.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram of a cleaning apparatus for cleaning semiconductor wafers according to the method of the present invention.

In the figure, 10 is a chuck that fixes a semiconductor wafer 11 as an object to be processed. The chuck 10 is rotated at a constant speed by a motor 12 connected directly below it. Above the chuck 10, high-pressure water 13, which is a cleaning liquid, is provided.
A cleaning liquid nozzle 14 that spouts out a cleaning liquid nozzle 14 reciprocates above the semiconductor wafer 11 through its rotation center point C. As shown in FIG. 2, the reciprocating movement of the cleaning liquid nozzle 14 is performed by a stepping motor 15 so that its moving speed can be varied. As shown in FIG. 3(A), if the stepping motor 15 has nine steps, the moving speed of the cleaning liquid nozzle 14 becomes maximum at the center point C of the semiconductor wafer 11 where the circumferential speed is the smallest, according to the triangular drive characteristic (1), and the circumferential speed increases. A predetermined variable speed is set so that the moving speed of the cleaning liquid nozzle J4 is the minimum in the vicinity of the semiconductor wafer 1 where the speed is highest (near points A and E). signal is supplied.

The driving characteristic of the stepping motor 15 may be a trapezoidal driving characteristic (It) as shown in FIG. 3). In short, the cleaning liquid nozzle 14 is moved quickly above the semiconductor wafer 11 where the circumferential speed is low, and the cleaning liquid nozzle 14 is moved slowly around the semiconductor wafer 11 where the circumferential speed is high. Any device that can eject flowing cleaning liquid for a certain period of time over the entire area may be used.

In the cleaning apparatus configured as described above, first, the semiconductor wafer 11 as the object to be processed is rotated at a constant speed by the chuck 1o. Next, an I pulse signal having predetermined drive characteristics is supplied to the stepping motor 15, and the cleaning liquid nozzle 14 is
is moved slowly at the periphery of the semiconductor wafer 1, and
The cleaning liquid such as high-pressure water 13 is sprayed onto the surface of the semiconductor wafer 1 while moving it faster as it approaches the center of rotation to clean dust and the like.

As described above, according to the method of the present invention, a uniform amount of cleaning liquid can be sprayed over the entire surface of the rotating semiconductor wafer 11. As a result, damage to the semiconductor wafer 1 can be prevented, and an effective cleaning process can be stably performed.

C. Effects of the Invention As explained above, according to the semiconductor wafer cleaning method of the present invention, by spraying a uniform amount of cleaning liquid over the entire surface of the semiconductor wafer, damage to the semiconductor wafer can be prevented. It is possible to prevent this and to stably perform effective cleaning treatment.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a cleaning device for cleaning a semiconductor unit by the method of the present invention, Fig. 2 is an explanatory diagram showing the movement of the cleaning liquid nozzle in the same cleaning device, and Figs. 3 and 6 are diagrams showing the movement of the cleaning liquid nozzle. A characteristic diagram showing the relationship between the moving speed and the position of the cleaning liquid nozzle, FIG. 4 is an explanatory diagram of a cleaning apparatus for cleaning semiconductor wafers by a conventional method, and FIG. 5 shows the movement of the cleaning liquid nozzle in the same cleaning apparatus. It is an explanatory diagram.

Claims (1)

[Claims] A step of rotating the semiconductor wafer at a predetermined speed, and moving a cleaning liquid nozzle onto the surface to be cleaned by moving the semiconductor wafer at a slower speed at the periphery and faster at the center with a trajectory passing from the outside of the semiconductor wafer through the center of rotation. A method for cleaning a semiconductor wafer, comprising the step of spraying a cleaning liquid from the cleaning liquid nozzle onto the surface of the semiconductor wafer while moving the semiconductor wafer in opposition to the surface.