JPH05315311A - Method for rinsing of a semiconductor wafer - Google Patents

Abstract

PURPOSE:To prevent sticking of particles and damage of a semiconductor element by adding surface-active liquid to pure water used for rinsing. CONSTITUTION:Surface-active liquid 10 is added to pure water for rinsing with a quantity-measuring pump 7 from a surface-active agent storing bath 6 through a valve 8. The pure water added with the surface-active liquid is supplied through shower 4 and bottom water supply 5 to a rinse bath 3, and rinsing of a wafer 1 is made. By adding the surface-active liquid, the surfaces of the wafer 1 and the wafer cassette 2 become hydrophilic. Therefore, sticking of particles can be suppressed. The adding amount of the surface-active liquid for suppressing foaming is less than critical micelle concentration, and it is about 100 to 200ppm. As a result, sticking of particles and electro-static damage can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for washing a semiconductor wafer with water, and more particularly to a method for washing a semiconductor wafer with less adherence of particles and less charge on the wafer.

[0002]

2. Description of the Related Art When a semiconductor wafer (hereinafter simply referred to as a wafer) is washed with water in the process of manufacturing a semiconductor device, ultrapure water having a specific resistance of about 18 MΩ is used as pure water.

As a washing method, as shown in FIG. 3, first, a wafer cassette 2 in which a wafer 1 is set is placed in a washing tank 3. The wafer cassette 2 is usually made of a fluorine resin (trade name: Teflon) and has almost no conductivity. Next, the wafer 1 is washed with water by supplying water from the shower 4 and the bottom water supply 5 to the water washing tank 3. After that, the wafer cassette 2 is pulled up from the water washing tank 3, and the wafer 1 and the wafer cassette 2 are dried by a method such as centrifugal drying.

[0004]

In this conventional method of rinsing with ultrapure water, if the wafer surface is hydrophobic, particles tend to adhere when the wafer passes over the water surface in the rinsing tank.

When centrifugal drying is performed after washing with water, there are problems that the wafer cassette and the wafer itself are easily charged, electrostatically adsorbing particles and electrostatically destroying semiconductor elements.

For example, a wafer 50 having a diameter of 150 mm
Put two wafers into two fluororesin wafer cassettes
When centrifugal drying is performed at 900 rpm using a centrifugal dryer as shown in (1), the wafer cassette is charged to about 3 kv.
Therefore, many particles adhere to the wafer and the semiconductor element is destroyed.

[0007]

The method for washing a semiconductor wafer with water according to the present invention is to add a surfactant to pure water to be used. As a result, since the surface of the wafer becomes hydrophilic, it is possible to reduce adhesion of particles during washing with water. In addition, since the surfaces of the wafer and the wafer cassette can be made to have weak conductivity, charging can be prevented.

[0008]

The present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a washing tank for explaining an embodiment of the present invention.

The surfactant 10 is added from the surfactant liquid storage tank 6 through the valve 8 to the pure water for washing with the metering pump 7. Pure water to which the surfactant 10 has been added is supplied from the shower 4 and the bottom water supply 5 to the washing tank 3 to wash the wafer 1.

As the surfactant 10, aliphatic alcohols, aliphatic amines, fatty acids and the like can be used, but they are limited to those having a relatively small molecular weight because of their water solubility. By adding the surfactant, the surfaces of the wafer 1 and the wafer cassette 2 become hydrophilic, so that the adhesion of particles can be suppressed. The amount of the surfactant added for suppressing foaming is 100 to 200 ppm, which is equal to or lower than the critical micelle concentration.
To a degree.

The wafer 1 may be washed with water using the centrifugal water washing / drying machine shown in FIG. That is, the wafer cassette 2A containing the wafer 1 is set in the chamber 9, and the wafer 1 and the wafer cassette 2 are set to 90
It is rotated at 0 to 1000 rpm, and pure water containing a surfactant is sprayed from the shower 4 to wash with water.
After that, stop the shower and perform centrifugal drying.

Also in this case, since the wafer and the surface of the wafer cassette have weak conductivity at the time of drying, it is possible to suppress the charge amount of the wafer cassette, prevent electrostatic adsorption of particles, and electrostatic breakdown of the semiconductor element. it can.

[0013]

As described above, according to the present invention, the surface of the semiconductor wafer is made hydrophilic by adding a surfactant to the pure water used for washing, and the adhesion of particles during washing is reduced. By imparting weak conductivity to the surfaces of the wafer and the wafer cassette to prevent charging, it is possible to prevent particles from adhering and electrostatic damage to the semiconductor element.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a washing tank for explaining an embodiment of the present invention.

FIG. 2 is a centrifugal washing for explaining an embodiment of the present invention.
The block diagram of a dryer.

FIG. 3 is a configuration diagram of a washing tank for explaining a conventional washing method.

[Explanation of symbols]

 1 Wafer 2, 2A Wafer Cassette 3 Washing Tank 4 Shower 5 Bottom Water Supply 6 Surfactant Storage Tank 7 Metering Pump 8 Valve 9 Chamber 10 Surfactant

Claims (1)

[Claims] 1. A method of rinsing a semiconductor wafer, wherein an aqueous solution obtained by adding a surfactant to pure water is used as the rinsing solution.