JPH05226311A - Cleaning equipment - Google Patents

Abstract

PURPOSE:To easily install a small-sized cleaning equipment in a clean room, by installing a first block equipped with a transferring equipment in the clean room, and installing a second block equipped with an isolation tank and a recirculation system outside the clean room. CONSTITUTION:A block 1 constitutes in a cleaning tank 10 storing a semiconductor wafer 100 and a casing 101 storing a transferring equipment 12. A block 2 constitutes in an isolation tank 20 which introduces supercritical fluid from the cleaning tank 10 the pressure of which fluid is reduced to be a specified value lower than or equal to the supercritical pressure by a pressure adjusting valve 13, and a casing 102 storing apparatuses for forming liquid in the supercritical state. The block 1 participating in direct cleaning is installed in the clean room, and the block 2 is installed outside the clean room. Thereby equipments to be installed in the clean room can be reduced and made small- sized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning apparatus for removing contaminants on an object to be cleaned by using a supercritical fluid in the manufacturing process of semiconductor wafers and the like.

[0002]

2. Description of the Related Art Recently, in order to improve the degree of integration of semiconductor wafers, removal of dirt on the wafer is a very important issue from the viewpoint of maintaining the quality of finished products. Various studies and developments have been made to solve this problem.

As one of the cleaning methods, "a method for cleaning a substrate with a supercritical gas or a liquefied gas and its apparatus" has been proposed (see Japanese Patent Laid-Open No. 63-179530).
It is described that the method uses a supercritical fluid to dissolve contaminants in the fluid and remove the contaminants, thereby removing the ester, fat and water.

FIG. 2 is a system diagram of a cleaning device based on this proposal. As shown in the figure, the cleaning tank 10 for containing the semiconductor wafer 100 and the separation tank 20 are connected by a pressure adjusting valve 13. The outlet side of the separation tank 20 has a pressure adjusting valve 21.
A recirculation system connected to the cleaning tank 10 via a filter 30, a cooler 32, a pressure feed pump 33, and a heater 34 via. In the figure, 22 is an extraction valve, 31 is a filter medium,
40, 50, 51, 52 and 60 are on-off valves.

The supercritical gas is introduced into the cleaning tank 10, the semiconductor 100 placed inside the cleaning tank is cleaned, and the contaminants are removed by depressurizing it in the separation tank 20. The pump is fed through the filter 30 and the cooler 32. After the pressure is increased by 33, it is recirculated as a fluid in a supercritical state by the heater 34.

[0006]

However, in this proposal, when the apparatus is used for cleaning semiconductor wafers, etc., no consideration is given to installing it in a clean room.

That is, even when CO ₂ which can be used at a relatively low pressure is used as the supercritical fluid, the pressure is about 80 to 10
A high pressure of 0 [kg / cm ² G] is required. Installing this high-pressure equipment in a clean room is because conventional semiconductor equipment is operated under normal pressure or reduced pressure.
It is necessary to install large-scale high-pressure equipment in the clean room. Therefore, not only enormous cost is required for the construction or maintenance of the clean room, but there is also a problem of installation space.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a small-sized cleaning device which can be easily installed in a clean room.

[0009]

In order to achieve the above object, the present invention provides a cleaning apparatus for dissolving contaminants adhering to the surface of an object to be cleaned with a supercritical fluid for cleaning, at least the cleaning apparatus being A first block including a cleaning tank for storing and cleaning the cleaning object, and a transfer device for transferring the cleaning object into and out of the cleaning tank; a separation tank for separating contaminants from the supercritical fluid; A second block having a supercritical fluid recirculation system from the separation tank to the cleaning tank, the first block is installed in a clean room, and the second block is installed outside the clean room. The first block and the second block are connected by a pipe through which a supercritical fluid flows.

[0010]

The equipment that needs to be operated in the clean room is a cleaning tank for accommodating and cleaning an object to be cleaned such as a semiconductor wafer, and a transfer device for taking the object in and out of the cleaning tank. Other equipment does not need to be installed inside the clean room and can be installed outside the clean room without any problem. Then, these facilities may be connected by two pipes through which a supercritical fluid can flow. By doing so, the clean room can be downsized and the space can be saved.

Further, this pipe becomes long, and there is a fear of pressure loss or heat loss, but the pressure is about 80 to 100 [k].
g / cm ² G], the pressure loss does not become a large ratio, and the temperature is about 40 ° C., which is relatively close to room temperature.
The measure can be taken with simple heat retention.

On the other hand, the high-pressure equipment installed in the clean room is a cleaning tank, and this cleaning tank has a minimum required size, that is, a size such that one object to be cleaned such as a semiconductor wafer can be stored, and the number of processes. Can be dealt with by increasing the number of tanks. As a result, even if trouble occurs in the high pressure equipment installed in the clean room, the damage can be minimized.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A cleaning device according to an embodiment of the present invention will be described with reference to FIG. This cleaning device consists of a first block 1 and a second block
Block 2 and is divided into two.

The block 1 includes a cleaning tank 10 for housing the semiconductor wafer 100, and a transfer device 12 for loading / unloading the semiconductor wafer 100 into / from the cleaning tank 10.
It is composed of items stored in 1.

The block 2 has a separation tank 20 for introducing the supercritical fluid from the cleaning tank 10 after depressurizing the supercritical fluid to a predetermined pressure below the supercritical pressure with a pressure control valve 13 and a pressure at the outlet side of the separation tank 20. A casing 1 which is connected to a filter 30 arranged via a regulating valve 21 and which houses devices for making a liquid in a supercritical state by a cooler 32, a pressure pump 33 and a heater 34.
It is composed of 02.

Cleaning tank 1 built in the block 1
0 is designed to have a minimum capacity that can accommodate one semiconductor wafer 100, and a plurality of cleaning tanks 10 are installed as shown in the figure. The cleaning tank 10 is provided with an opening for loading and unloading the semiconductor wafer 100, and an opening / closing lid 11 designed to withstand the internal pressure is attached to the opening.

In the cleaning tank 10, a line for introducing the supercritical gas through the opening / closing valve 51, a line for discharging the supercritical gas through the opening / closing valve 52 and sending the supercritical gas to the separation tank 20 of the block 2, and a discharge valve. Lines communicating with the exhaust line through 53 are connected to each other.

The block 2 is provided with a bypass line 54 which is connected from the outlet of the heater 20 through the opening / closing valve 50 to the front side of the pressure valve 13.

The block 1 directly involved in the cleaning is installed inside the clean room, and the block 2 is installed outside the clean room.

The semiconductor wafers 100 to be cleaned are inserted one by one into the cleaning tank 10 by the transfer device 12, the opening / closing lid 11 is closed, and the opening / closing valve 51 is opened to introduce the supercritical gas. The supercritical gas dissolves contaminants such as water, oil and fat, and ester on the semiconductor wafer 100, and then flows through the opening / closing valve 52 into the separation tank 20 of the block 2. At this time, the pressure adjusting valve 13 reduces the pressure to a level below the supercritical pressure to deposit dissolved contaminants in the fluid, and then passes the filter 30 and the cooler 32 through the pressure adjusting valve 21 and the pressure feed pump 33.
To raise the pressure above the supercritical pressure. Then, the temperature is raised by the heater 34 to bring the fluid into a supercritical state, and the fluid is recirculated to the cleaning tank 10 of the block 1.

As described above, a plurality of cleaning tanks 10 for the block 1 are installed, and the cleaning tank 10 that has completed cleaning closes the on-off valves 51 and 52 and the discharge valve 53 to open the internal pressure of the cleaning tank 10 to the atmospheric pressure. After that, the opening / closing lid 11 is opened and the semiconductor wafer 100 is taken out. At this time, since a plurality of cleaning tanks 10 are installed, the other cleaning lines are still operating,
Each equipment of block 2 can continue normal operation. Therefore, the operation status of the block 1 does not directly affect the operation of the block 2, and the two blocks 1,
There is no problem even if 2 is installed at a distant position.

At the time of start-up or when all the cleaning devices are stopped, the block 2 can be operated independently by opening and closing the opening / closing valve 50 of the bypass line 54 in the block 2 to operate the block 2 independently. It is not necessary to install it in a clean room as a single unit.

The cleaning tank 10 has a minimum size required to process the semiconductor wafers 100 one by one, and the pressure of the cleaning tank 10 can be brought to normal pressure in a short time by opening the discharge valve 53. it can. When a trouble occurs in one of the cleaning tanks 10, it can be dealt with by setting only the line of the cleaning tank 10 to the normal pressure. In addition, even if a high-pressure rupture occurs, it will not cause damage enough to affect surrounding equipment.

Although the present embodiment has described the semiconductor cleaning apparatus which particularly dislikes the installation of high-voltage equipment, the present invention is not limited to semiconductor cleaning, and other members may be cleaned depending on the conditions of the installation site. When a separate installation is desirable, it is especially effective for installation in locations where high-voltage equipment is difficult to install.

[0025]

The present invention is constructed as described above, and the equipment installed in the clean room can be reduced in number and downsized, so that the installation space in the clean room can be reduced to approximately one fifth or less. .

Further, by reducing the volume of the high-pressure equipment installed in the clean room, the safety is increased, the safe installation can be carried out in the clean room, and no special safety measures are required.

[Brief description of drawings]

FIG. 1 is a system diagram of a cleaning device according to an embodiment of the present invention.

FIG. 2 is a system diagram of a conventional cleaning device.

[Explanation of symbols]

 1 1st block 2 2nd block 10 Cleaning tank 11 Opening / closing lid 12 Transfer device 20 Separation tank 30 Filter 32 Cooler 33 Pressure pump 34 Heater 100 Semiconductor wafer 101, 102 Casing

Claims (1)

[Claims] 1. A cleaning device for dissolving contaminants adhering to the surface of an object to be cleaned with a supercritical fluid for cleaning, wherein the cleaning device stores at least the object to be cleaned and a cleaning device for cleaning the same. A first block equipped with a transfer device for loading and unloading an object to be cleaned, a separation tank for separating contaminants from the supercritical fluid, and a recirculation of the supercritical fluid from the separation tank to the cleaning tank. And a second block having a system, the first block is installed in a clean room, the second block is installed outside the clean room, and the first block and the second block are separated. A cleaning device in which the spaces are connected by a pipe through which a supercritical fluid flows.