JPS6127637A - Semiconductor wafer drier - Google Patents

Abstract

PURPOSE:To provide an efficient drier of semiconductor wafer with larger diameter or fine and deep groove almost vertically formed into the wafer surface by a method wherein a sort of gas with constant pressure mole heat capacity larger than that of air is heated into laminar flow in parallel with a wafer surface to be brought into contact with the wafer. CONSTITUTION:A wafer supporter 6 is inserted into a drying chamber and then heated by hot air of carbon dioxide 15 to evaporate most of the water content adhering to a semiconductor wafer for the first 1min. The carbon dioxide 15 is blown by a Roots type blower 1 to be filtered by a cartridge filters 2 for screening any larger particles. After blowing for 1min, the carbon dioxide is heated by a cartridge heater 3 to finish the heating process within two or 3min. The carbon dioxide 15 may be circulated to repeat wafer heating process without discharging outside. Besides, a carbon dioxide supplying unit 13 is provided since a bit of carbon dioxide 15 is wasted in case the wafer supporter 6 is inserted into or pulled out of the drying chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a semiconductor wafer drying apparatus for drying semiconductor wafers using hot air.

(Prior art) Conventionally, a device for drying a wet semiconductor wafer after cleaning using hot air heats air and brings the heated air into a laminar flow state parallel to the surface of the semiconductor wafer and brings it into contact with the semiconductor wafer. Toto Kyoshi was being carried out. This is explained in the Journal of Electro
nic Materia 1g Volume 8, Kuzu 6 (1979)
P, 855-864) will be explained as an example.

This will be explained with reference to FIG. Insert the wafer support 6 into a drying chamber (not shown);2. ．． By applying cold air at a rate of 5 m/sec, most of the water adhering to the surface of the semiconductor wafer 5 is removed in the first minute. The air is RIOo
It is supplied by a ts-type blower 1 and filtered by a cartridge filter 2 having 3 x 3 cartridges arranged in series and parallel. This is 0
Particles larger than 2 μm are separated by toolp. After blowing air for 1 minute, cartridge heater 3 pumps air 14 to about 10
Heat to 0°C. Drying is completed in 2 to 3 minutes. The wafer support stand 6 is taken out from the drying chamber. Dry using the above steps.

By the way, as a trend in semiconductor manufacturing technology, new production lines currently mainly use 5-inch wafers, but are now moving to 6-inch wafers in order to further improve production efficiency. When the wafer has a large diameter of about 6 inches, the weight of one wafer becomes large, and therefore its heat capacity also becomes large. When the heat capacity of the wafer increases, in the conventional drying method using hot air, even if hot air heated to 100°C is applied, when it comes into contact with the semiconductor wafer, the temperature of the hot air drops much more than in the case of a small-diameter semiconductor wafer. Therefore, the problem is that it takes time for the water to evaporate, which delays drying and leaves stains.

In addition, in recent years, as integrated circuits have become denser and faster, there has been a demand for a method for processing semiconductor circuit boards that is different from conventional methods. In other words, vertical fine deep grooves are formed on the surface of the semiconductor substrate using reactive sputter etching, and device isolation is achieved by filling these fine deep grooves with an insulating material. The capacitance is increased by effectively increasing the area by forming an insulating film on the inner wall of a fine deep groove.

When the inner walls of these fine deep grooves formed almost perpendicularly on the surface of the semiconductor wafer are dried using the conventional drying method using hot air, the moisture adhering inside the fine deep grooves evaporates at a sufficient rate. Since the drying speed is not fast, there is a problem that drying is insufficient and stains are formed.

(Object of the Invention) The object of the present invention is to handle large-diameter semiconductor wafers that are insufficiently dried using conventional drying techniques using hot air, and semiconductor wafers that have deep, narrow grooves that are processed and formed almost perpendicularly to the surface of the semiconductor wafer. - To provide a drying device using hot air that is effective for drying.

(Structure of the Invention) A semiconductor wafer drying apparatus for drying the semiconductor wafer 1 of the present invention using hot air heats a gas having a constant pressure molar heat capacity larger than that of air, and flows the heated gas in a laminar flow parallel to the semiconductor wafer surface. This is a semiconductor wafer drying apparatus characterized in that the semiconductor wafer is dried by bringing the semiconductor wafer into contact with the semiconductor wafer.

(Function) According to the present invention, since a gas having a constant pressure molar heat capacity larger than air is heated and used, even a substance having a large latent heat of vaporization, such as water, can be evaporated in a short time.

(Effects of the Invention) The present invention heats and uses a gas having a molar heat capacity at constant pressure greater than that of air. This method has the effect of drying a semiconductor wafer with hot air in a short time, which has a large amount of attached moisture and has fine deep grooves formed almost perpendicularly to the surface of the semiconductor wafer.

(Example) This will be explained with reference to FIG. Insert the wafer support 6 into a drying chamber (not shown) and apply hot air containing 15 carbon dioxide at a rate of 2.5 m/sec to remove most of the water adhering to the semiconductor wafer in the first minute. except.

Carbon dioxide 15 is supplied by an OTS-type blower 1 and filtered by a cartridge Φ filter 2 arranged in series and parallel with 3×3 cartridges. Now particles larger than 0.2 μm are 100%
They are sent door to door. After blowing air for 1 minute, the cartridge heater 3 heats carbon dioxide 15 to about 100°C. Drying is 2
~ Get a wife and child in 3 minutes. The wafer support is pulled out from the drying chamber and drying is completed.

Using the above drying method, we formed MOS diodes in fine deep grooves almost perpendicular to the surface of the semiconductor wafer and measured the generation lifetime of minority carriers, and found that the generation lifetime was approximately twice as long as that of the conventional method. Good results were obtained.

In this example, carbon dioxide 15 was used by being circulated without being discharged to the outside. A carbon dioxide supply section 13 is provided since some carbon dioxide is lost when the wafer support is inserted into and withdrawn from the drying chamber.

Although there is no specific cooling section for carbon dioxide, it can be installed when it is necessary to increase the efficiency of removing water contained in carbon dioxide. Further, the semiconductor wafers inserted into the drying chamber may be processed one by one, or a large number of semiconductor wafers may be processed in batches.

(Summary of the Invention) The present invention is a semiconductor wafer drying apparatus that dries semiconductor wafers using hot air, and by heating and using a gas having a higher constant pressure molar heat capacity than air, it has a high latent heat of vaporization like water. Hot air drying of large-diameter semiconductor wafers with a large heat capacity and large heat capacity to which substances have adhered, as well as semiconductor wafers with a large amount of adhered moisture and having fine deep grooves processed almost perpendicular to the surface, can be carried out in a short time without producing any oozing. .

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a conventional hot air drying device for semiconductor wafers.
FIG. 2 is a schematic diagram of a hot air drying apparatus for semiconductor wafers, which is an embodiment of the present invention. 1...Roots type blower, 2...Cartridge filter, 3...Cartridge heater, 5...Wafer, 6...Weno・Support stand, 7...Thermocouple. 13... Carbon dioxide supply section, 14...
Air, 15...Carbon dioxide. * 1 ■ Ri

Claims (1)

[Claims] In a semiconductor wafer drying apparatus that dries a semiconductor wafer using hot air, a gas having a constant pressure molar heat capacity larger than that of air is heated, and the heated gas is brought into a laminar flow parallel to the surface of the semiconductor wafer. Let me come into contact with you,
A semiconductor wafer drying apparatus characterized by drying the semiconductor wafer.