JPH06104236A - Wafer cleaning apparatus - Google Patents

Abstract

PURPOSE:To provide a wafer cleaning apparatus, wherein steam is first supplied to turn wafers hydrophilic so that they be evenly cleaned. CONSTITUTION:Steam 16 is supplied into a chamber 1a, a spontaneous oxide film is formed on the surface of a wafer 3 and the surface of the wafer 3 is made hydrophilic. The wafer 3 is conveyed into a chamber 1b, and the wafer 3 is cleaned by hydrogen fluoride gas or hydrogen fluoride vapor 9. Since the surface of the wafer 3 has been made hydrophilic, it can be cleaned easily by the hydrogen fluoride gas or the hydrogen fluoride vapor. Thereby, a cleaning irregularity and a fog are not caused irrespective of the surface state of the wafer in its cleaning operation, it is possible to prevent a cause lowering a device characteristic and the wafer can be cleaned with extremely high cleanliness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer cleaning apparatus for cleaning a wafer in a semiconductor manufacturing process.

[0002]

2. Description of the Related Art In the manufacturing process of silicon wafers,
The surface of the silicon wafer needs to be kept clean. For example, contamination such as foreign matter adhering to the surface of the silicon wafer during photo-etching may cause a wiring short circuit or disconnection. However, in order to improve the performance and reliability of the product, such as the alloying of the alloys with each other to short-circuit the pn junction, it is necessary to reduce contaminants on the surface of the silicon wafer as much as possible.

Therefore, even during the silicon wafer manufacturing process, there are cleaning processes such as pre-cleaning before oxide film formation and post-cleaning after photo-etching. In the conventional hydrogen fluoride vapor cleaning, as shown in FIG. 2, the wafer 3 is heated by the heating plate 5 in the chamber 1 and the motor 1 is used.
4, the hydrogen fluoride gas or hydrogen fluoride vapor 9 is supplied into the chamber 1, and the exhaust pipe 7 exhausts (1
3) Then, the wafer 3 is cleaned with this hydrogen fluoride gas or hydrogen fluoride vapor 9.

[0004]

Conventionally, the wafer 3 is cleaned with hydrogen fluoride gas or hydrogen fluoride vapor. However, depending on the surface condition of the wafer 3, it is not always hydrophilic but hydrophobic. Therefore, there is a problem in that the hydrogen fluoride gas or the hydrogen fluoride vapor alone causes a factor that deteriorates the device characteristics, such as uneven cleaning and clouding.

Therefore, an object of the present invention is to provide a wafer cleaning apparatus having a uniform cleaning function by supplying steam to the wafer to make the surface hydrophilic before cleaning.

[0006]

In order to solve the above problems, a wafer cleaning apparatus according to the present invention cleans a wafer in a water vapor atmosphere with hydrogen fluoride gas or hydrogen fluoride vapor.

[0007]

In the present invention, pure water vapor causes about 1
By forming a natural oxide film having a thickness of about nm, the surface of the wafer is made hydrophilic so that it can be easily cleaned with hydrogen fluoride gas or hydrogen fluoride vapor, and uniform cleaning is performed.

[0008]

FIG. 1 shows an embodiment of the cleaning apparatus of the present invention.

The processing chamber 1a is precleaned, and the surface of the wafer 3 is lightly cleaned by making the wafer 3 hydrophilic by steam,
The chamber 1b is for the purpose of performing the main cleaning, but the same chamber can be used. In this embodiment, the two-chamber system is used.

The chambers 1a and 1b have a closed structure, and the material is Teflon resin, for example. The pressure in the chambers 1a and 1b is normal pressure in the embodiment, but may be increased or decreased. Since the chamber 1a is a chamber for making the surface of the wafer 3 hydrophilic, a heater 6 is installed around the chamber. It is sufficient that the heating temperature of the heater 6 is about 100 ° C., and heating is performed continuously or intermittently.

Pure water 11a is converted into steam (11) by, for example, a heat exchanger 10 and supplied from the upper part of the chamber 1a. A current plate 2 is installed to make the supply state uniform. Further, the exhaust pipe 7 provided with a switching valve 8 for hermetically sealing vapor and exhausting hydrogen fluoride is composed of the chambers 1a, 1
It is a pipe connecting b and the valve 8 and is exhausted (13) through the valve 8 of the exhaust pipe 7.

A holding table 4 for holding the wafer 3 in the chamber 1a
And is heated by the heating plate 5 and the heater 6. The heating temperature of the heating plate 5 is room temperature to about 100 ° C. Steam 1 with the chamber 1a heated
It is preferable to rotate the wafer 3 by the motor 14 during the supply of supplying 1. Rotation speed is 10-100r
It is about pm.

By supplying the water vapor 11 for several minutes (1 to 10 minutes), a natural oxide film of about 1 nm is formed on the wafer 3 to make the surface of the wafer 3 hydrophilic and hydrogen fluoride gas or fluorinated gas. Even hydrogen vapor can be easily cleaned, and it is uniform (etching variation is 1-2.
%). Since the hydrophilic film is cleaned, partial cleaning unevenness and fogging do not occur. After that, the partition plate 12 is opened, the wafer 3 is transferred to the chamber 1b, and cleaning is performed only with the hydrogen fluoride gas or the hydrogen fluoride vapor 9.

[0014]

As described above, according to the present invention, it is possible to perform cleaning with extremely high cleanliness without causing uneven cleaning or fogging regardless of the wafer surface state at the time of cleaning, preventing factors that deteriorate device characteristics.

[Brief description of drawings]

FIG. 1 is a schematic view of a cleaning device according to an embodiment of the present invention.

FIG. 2 is a schematic view of a conventional cleaning device.

[Explanation of symbols]

 1a Chamber (pre-cleaning) 1b Chamber (main cleaning) 2 Rectifier plate 3 Wafer 4 Holding table 5 Heating plate 6 Heating heater 7 Exhaust pipe 8 Valve 9 Hydrogen fluoride gas or hydrogen fluoride vapor 10 Heat exchanger 11 Steam 11a Pure water 12 Partition plate 13 Exhaust 14 Motor

Claims (1)

[Claims] 1. A wafer cleaning apparatus, which cleans a wafer in a water vapor atmosphere with hydrogen fluoride gas or hydrogen fluoride vapor.