JPH06196540A - Vacuum device - Google Patents

Abstract

PURPOSE:To prevent the contamination of a wafer induced by particles generated by the condensation of aqueous vapor during vacuum exhaust operation by installing a substrate to be processed, such as a wafer to a spot which is not subject to the condensation of aqueous vapor. CONSTITUTION:After a wafer 1 is loaded on a sample mount 8 in an auxiliary exhaust vacuum chamber 4 and a take out and take in port 9 is closed, a sample mount drive device 13, which moves up and down the sample mount 8, is operated to move the sample mount 8 where the wafer 1 is loaded during vacuum exhaust. The distance between the wafer 1 and the wall surface of the auxiliary exhaust vacuum chamber 4 is specified to be within 25mm during this operation. Since the heat transfer from the wall surface prevents a drop in the temperature of a space to be processed, the condensation of aqueous vapor induced by temperature drop accompanied by insulation expansion during vacuum exhaust operation, is not produced easily in a space 12 on a surface to be processed so that it may be possible to prevent the contamination of the wafer induced by condensed water drops or ice.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum apparatus having a vacuum chamber for preliminary exhaust for carrying in a processed substrate such as a wafer and performing preliminary exhaust.

[0002]

2. Description of the Related Art In a conventional apparatus, dust is generated due to mechanical friction of a transfer part during vacuum evacuation in a preliminary exhaust vacuum chamber, when opening to the atmosphere, or when a wafer is transferred, and the dust is rolled up and adheres to the wafer. In order to prevent the
As described in Japanese Laid-Open Patent Publication No. 62-209825, a method of covering a substrate to be processed such as a wafer with a cover during evacuation, opening to the atmosphere, or wafer transfer has been used.

[0003]

However, the above-mentioned prior art is concerned with the prevention of adhering dust that is wound up during evacuation, and the influence of condensation of water vapor that occurs during evacuation is not taken into consideration. When condensed, there is a problem that contamination is caused by fine dust that serves as a core, and wafer contamination is caused by adhesion of water itself.

An object of the present invention is to install a processing substrate such as a wafer in a place where there is no influence of condensation of water vapor.
It is an object of the present invention to provide a vacuum device capable of preventing wafer contamination by particles generated by condensation of water vapor during vacuum evacuation.

[0005]

In order to achieve the above object, the present invention provides a substrate to be processed such as a wafer during vacuum evacuation.
It has a structure to be installed or moved near the wall surface where water vapor does not easily condense.

[0006]

According to the present invention, the substrate to be processed such as a wafer is installed or moved near the wall surface where the temperature drop due to adiabatic expansion is small and water vapor condensation is less likely to occur during vacuum exhaust, so that the processed substrate such as a wafer is less likely to be contaminated. .

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the vacuum evacuation method of the vacuum processing apparatus of the present invention. In the figure, 1 is a substrate to be processed such as a wafer, 2 is a processing chamber that is kept in a high vacuum in advance, 3 is an exhaust port of the processing chamber, 4 is a substrate to be processed such as a wafer, and the vacuum in the processing chamber is broken. For pre-exhaust vacuum chamber for carrying out and carrying in without carrying out, 5 is an exhaust port of the pre-exhaust vacuum chamber, 6 is a gas inlet of the pre-exhaust vacuum chamber, and 7 is a processing chamber and a pre-exhaust vacuum chamber. A gate valve for partitioning the space, 8 is a sample stage on which the substrate to be processed is placed, and 9 is a carry-in / carry-in port of the substrate to be processed.

In the apparatus thus constructed, the gate valve 7 is closed in advance, and the processing chamber 2 is evacuated from the exhaust port 3 to maintain a high vacuum. The wafer 1 is loaded and unloaded from the loading / unloading port 9 on the sample table 8 in the preliminary exhaust vacuum chamber 4, and the loading / unloading port 9 is closed. The wafer 1 faces the wall surface of the pre-evacuation vacuum chamber 4, and the distance between the wafer 1 and the wall surface is within 25 mm. Next, vacuum exhaust is performed from the exhaust port 5.

FIG. 2 is a characteristic diagram showing the operating principle of the present invention.
It shows the relationship between the distance from the wall surface to the wafer and the minimum temperature reached by the temperature lowered by adiabatic expansion. From FIG. 2, it can be seen that the temperature does not easily drop at a position within about 25 mm from the wall surface. Therefore, if the processing surface of the wafer 1 is within 25 mm from the wall surface of the vacuum chamber 4 for preliminary evacuation, the temperature of the space 12 above the processing surface is less likely to decrease due to heat transfer from the wall surface, and adiabatic expansion during vacuum evacuation is performed. Condensation of water vapor due to the temperature decrease due to the temperature decrease is unlikely to occur in the space 12 on the processing surface, and the water droplets condensed on the wafer 1 or contamination by ice is prevented.

FIG. 3 shows a second embodiment of this device. After the wafer 1 is placed on the sample table 8 and the carry-out / in port 9 is closed, when the vacuum exhaust is performed, the sample table drive device 13 for moving the sample table 8 up and down moves the sample table 8 on which the wafer 1 is placed. To raise. At this time, if the distance between the wafer 1 and the wall surface of the pre-evacuation vacuum chamber 4 is within 25 mm, the space 1 on the processing surface is transferred by heat transfer from the wall surface, as in the first embodiment.
Since the temperature of 2 is unlikely to drop, the condensation of water vapor is less likely to occur, and the water droplets condensed on the wafer 1 or contamination by ice is prevented.

FIG. 4 shows a third embodiment of this device. In the first and second embodiments,
A space 12 on the processing surface of the wafer having means 14 and 15 for heating the wall surface of the vacuum chamber 4 for preliminary evacuation or the sample table 8.
By heating, the generation of particles due to condensation of water vapor is eliminated during evacuation, and contamination of the processed substrate such as a wafer is prevented.

FIG. 5 shows a fourth embodiment of the present apparatus. After the wafer 1 is unloaded and loaded from the loading port 9 onto the sample stage 8 in the pre-evacuation vacuum chamber 4 and the loading and unloading port 9 is closed, the cover driving device 16 removes the cover 17 containing the heater. The gap between the wafer 1 and the wafer 1 is lowered to the utmost, and vacuum exhaust is performed from the exhaust port 5. Since the space 12 on the processing surface of the wafer 1 is warmed and the temperature does not drop sufficiently, condensation does not occur and wafer contamination is prevented.

FIG. 6 shows a fifth embodiment of the present apparatus. In the figure, 18 is an infrared radiation source and 19 is a reflector. When the vacuum exhaust is performed, infrared rays are radiated into the preliminary exhaust vacuum chamber 4 and are reflected by the reflection plate to form an infrared net on the processing surface of the wafer 1. When the infrared net is formed on the processing surface, the temperature of the space 12 on the processing surface decreases. Is suppressed and the condensation of water vapor does not occur, so that the contamination of the wafer due to the condensation is prevented.

FIG. 7 shows a sixth embodiment of the present apparatus. In the figure, 20 is a microwave generator. At the time of vacuum evacuation, microwaves are generated in the preliminary evacuation vacuum chamber 4 and set to the excitation frequency of water, so that water vapor condensation occurs due to a temperature drop due to adiabatic expansion during vacuum evacuation. Prevents wafer contamination from water droplets or ice.

FIG. 8 shows a seventh embodiment of the present apparatus. In the figure, 21 is a sample stage rotating mechanism.
After the wafer 1 is loaded and unloaded from the loading port 9 and placed on the sample table 8 in the pre-evacuation vacuum chamber 4 and the loading and unloading port 9 is closed,
The sample table 8 is rotated by the sample table rotating mechanism 21. By placing the wafer 1 vertically (illustrated) or by setting the processing surface of the wafer 1 downward, particles that are generated by condensation of water vapor and settle down are less likely to adhere to the processing surface, and the contamination of the wafer is prevented. To be prevented.

[0017]

According to the present invention, when evacuation is performed in the pre-evacuation vacuum chamber, water vapor does not condense in the space above the processing surface of the wafer or the like, or particles are generated by the water vapor condensation. However, since it does not easily adhere to the wafer, particles (water droplets, etc.) generated by condensation of water vapor during vacuum evacuation
Wafer contamination due to ice can be prevented.

[Brief description of drawings]

FIG. 1 is a side view of a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing the operating principle of the present invention.

FIG. 3 is a side view of the second embodiment of the present invention.

FIG. 4 is a side view of the third embodiment of the present invention.

FIG. 5 is a side view of the fourth embodiment of the present invention.

FIG. 6 is a top view of the fifth embodiment of the present invention.

FIG. 7 is a side view of the sixth embodiment of the present invention.

FIG. 8 is a side view of the seventh embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate to be processed such as wafer, 2 ... Processing chamber, 3 ... Processing chamber exhaust port, 4 ... Pre-evacuation vacuum chamber, 5 ... Pre-evacuation vacuum chamber exhaust port, 6 ... Pre-evacuation vacuum chamber gas Introducing port, 7 ... Gate valve, 8 ... Sample table, 9 ... Unloading and carrying-in port of substrate to be processed.

Claims (1)

[Claims] 1. A vacuum apparatus equipped with a pre-evacuation vacuum chamber for carrying in a substrate to be processed such as a wafer and performing pre-evacuation, wherein the processing surface of the wafer or the like is in the pre-evacuation vacuum chamber during vacuum evacuation. A vacuum device characterized by having a structure facing the wall surface of, and having a gap within 25 mm.