JPS6341716B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a downward blowing air cleaning device, particularly to a continuous air cleaning chamber or a single unit air cleaning device used for semiconductor wafer processing or integrated circuit wafer processing.

This type of air purifying device uses semiconductor wafers, integrated circuit wafers (hereinafter simply referred to as wafers),
0.3μ to prevent airborne dust from adhering to the wafer surface when exposing the wafer.
This equipment allows wafers to be stored and transported in air filtered by high-performance filters that can filter out up to 99.999% of the above dust.

In this air cleaning device, the equipment used to store wafers is particularly called a clean bench. In addition, it is directly connected to the factory layout in semiconductor factories and integrated circuit factories, and is connected to wafer processing equipment so that wafer handling can be carried out in a clean atmosphere. ) may be provided.

In this single equipment clean bench and clean tunnel, in the downflow method that blows clean air from the upper part to the lower part, if the distance from the filter blowing surface to the position where the wafer is manipulated is large, the clean air will not reach. If a wafer is stored for a long time in a clean bench or clean tunnel located beyond this limit distance, airborne dust will adhere to the wafer surface, and if the wafer is transported to the next process for processing, the wafer will It has been found that this causes the pellet yield, that is, the yield, to be extremely reduced.

Furthermore, the jigs and tools used for wafer processing also have the disadvantage that dust adheres to them, causing secondary contamination.

As shown in FIG. 1, this type of conventional air purifying device is equipped with a final filter 1, a fan 2, and a pre-filter 3 in a hood 4, and a clean hood punching plate 5 is attached to the clean air outlet 4A of the hood 4. , which was installed above a clean room R divided by partitions 6.

Then, by operating fan 2, prefilter 3
The outside air _A1 is sucked into the hood 4 through the hood 4 and compressed.Then, the compressed air _A2 is passed through the final filter 1, and the clean air _A3 is passed through the clean hood punching plate 5 to the clean room below. R
It flows inward in a laminar flow.

Clean air A ₃ is blown down into the clean room R at the required speed, but as it moves away from the filter surface, external air A ₄ other than clean air A ₃ sweeps away the clean air flow whose wind speed has weakened and becomes cleaner. Infiltrated into the work space above the work desk 7 installed in room R,
Further, the furnace core tube or processing tube 9 inserted into the diffusion furnace or machine 8 is opened into the clean room R with its working opening facing into the receiving box 10, so that it is stored on the working desk 7. Clean processing material is air A ₅ containing dust that has entered the outside air or flowed out from inside the processing pipe 9.
Not only is this extremely contaminated, but also the dust generated by workers working in front of the work desk 7.
Since the clean air A ₃ flowing in the direction above the work table 7 flows in, there is a drawback that the material to be processed on the work table 7 cannot be contaminated.

The present invention provides a downward blowing air cleaning device that can maintain cleanliness on a work desk without any modification to the conventional filter and fan structure.

In order to achieve the above object, in the lower blowing air purifying device of the present invention, a hood with a built-in filter is provided above the cleaning chamber whose front is open and the working opening of the processing pipe is exposed to the rear partition. A slit is installed on the front and rear edges of the clean air outlet that communicates with the clean air outlet opened on the bottom surface to blow clean air down into the clean room and form an air curtain at the front and rear edges of the work space. A day user is provided at the air discharge port to discharge clean air into the work space, and the hole diameter of the hole opened in the day user is gradually increased from the rear side of the clean room toward the open front part. It is.

According to the present invention, an air curtain is formed on the lower surface of the clean air outlet of the hood passing through the filter to forcefully blow clean air down to the front and rear of the work space to block external air, and between the two air curtains, The system is characterized by installing day users with pore diameters that are successively changed, and allowing the clean air blown out from the day users to flow through the work space at an angle between the front and rear air curtains, as if it were a cross flow. It is something.

Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 2, an air cleaning device is installed above a clean room 12 divided by a partition 11.

The air cleaning device has a final filter 14 and a fan 15 housed in a hood 13, and a prefilter 16 attached to a part of the wall surface.

A clean air outlet 17 is opened at the bottom of the hood 13, and slits 18, 19 are provided along the front and rear edges of the outlet 17 to have a required slit width.
is installed, and between both slits 18 and 19, day users 20, 21, 22 with different hole diameters are installed.
is arranged. Dehy user 20,2
The hole diameter of the hole (mesh) opened in 1 and 22 is
The pore diameter of the rearmost day user 20 is the smallest,
The diameter of the hole increases in the order of the day users 21 and 22 toward the front. A work table 23 is placed in the clean room 12 directly below the clean air outlet 17, and a furnace core tube or processing tube inserted into a diffusion furnace or machine 25 is placed in a receiving box 24 attached to the partition 11. The point that 26 working openings are facing is the same as the conventional one.

In the embodiment, external air A ₁₀ is passed through the prefilter 16 to the hood 1 by operation of the fan 15.
The compressed air A ₁₁ is pumped into the final filter 14 . The clean air that has passed through the filter 14 passes through the slits 18 and 19 provided at the discharge port 17 and each day user 2.
0, 21, 22, front and rear slits 18,
Air curtains C ₁ and C ₂ are formed from air curtains 19 and blown down into the clean room 12 along the front and back of the working space, and the clean air A ₁₂ , A ₁₃ , A ₁₄ blown out from each day user 20 , 21 , 22 is The wind speed varies depending on the diameter of each hole, and the wind flows toward the front of the workbench 23 at no angle as if it were a cross flow.
The air flows towards the worker working in front of the work desk 23 in the same way as in the case of a horizontal blowout, and flows out to the front of the work desk 23.

In addition, the air curtain C ₂ formed by the clean air discharged from the slit 19 entrains the dust flow A ₁₅ from the machine room side and the inside of the processing pipe 26 and blows it downward from the rear of the work desk 23. Flow.

Further, the air curtain C ₁ formed by the clean air discharged from the slit 18 blocks the clean air blown down from each day user 20 to 22 from outside air, and the air flow of the air curtain C ₁ is as follows:
As the flow rate decreases downward, it flows outward from the front of the work desk, thereby preventing external air from being drawn onto the work desk 23.

Therefore, the work space above the work desk 23 is isolated by the front and rear air curtains C ₁ and C ₂ , and outside air and dust are not mixed in, and the work space on the work desk 23 is isolated by the front and rear air curtains C 1 and C 2 .
It is maintained clean by being supplied with clean air flowing out from ports 0, 21, and 22.

As described above, the present invention includes the slits 18 and 19 provided at the front and back of the upper part of the clean chamber 12, and the slits 18 and
By combining day users 20 to 22 with different meshes provided between slits 18 and 19 and day users 20 to 22, changes in air resistance of clean room air ejected from each slit 18 and 19 and day users 20 to 22 are used to remove external air and dust. Since the flow is blocked, the work space in the clean room 12 can be kept clean to the extent necessary for the work, the wafers handled on the work table 23 are not contaminated, and the product yield can be improved. can.

The present invention has the effect of maintaining and improving the cleanliness on a work desk by improving only the outlet of the hood without making any changes to the structure of the filter and fan of the conventional air purifying device.

[Brief explanation of drawings]

FIG. 1 is a side view of a conventional lower blowing air cleaning device, and FIG. 2 is a side view showing an embodiment of the device of the present invention. 12...Clean room, 13...Hood, 14...Final filter, 17...Clean air outlet,
18, 19...slit, 20-22...dehyde user, _C1 , _C2 ...air curtain, _A12 , _A13 ,
A ₁₄ ...Clean air.

Claims (1)

[Claims] 1. A hood with a built-in filter is installed above the clean room with the front open and the working opening of the processing pipe facing the rear partition, and the front and rear edges of the hood are connected to the clean air outlet opened on the bottom surface of the hood. A slit is installed to blow clean air down into the clean room to form an air curtain at the front and rear edges of the work space, and a day user is installed at the clean air outlet between the two slits to allow the clean air to flow out into the work space. A lower blowing air cleaning device characterized in that the diameter of the hole opened in the dehydrator is gradually increased from the rear side of the clean room toward the open front part.