JP3350890B2 - Clean room cleanliness control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling cleanliness in a clean room, which can be used to control the cleanliness in a clean room used in a semiconductor factory or the like.

[0002]

2. Description of the Related Art Conventionally, semiconductors such as LSIs are manufactured in a clean room, and only the concentration of dust in the air is controlled in the manufacturing process.

[0003] The removal device for removing such dust components includes:
A trapping filter such as a HEPA filter or an ULPA filter or an adsorption filter such as a chemical filter using chemical adsorption is used to clean air containing much dust.

FIG. 3 shows an example of such an air conditioning system for a clean room. In the figure, reference numeral 101 denotes an air purifying device,
A ceiling chamber 101A is stretched over the upper portion of the ceiling chamber 101, and HE filter is provided on the entire lower surface of the ceiling chamber 101A as a filter.
A PA filter 102 is laid, and a floor 103 having many suction holes 103A is provided. The air purifying apparatus 101 includes the above-described ceiling chamber 101A and the clean room 101 by the HEPA filter 102 and the floor 103.
B and an underfloor chamber 101C.

[0005] On one side of the air cleaning device 101, a blower 1
One end of a first circulation duct 105 is connected to one side of a chamber 104A in which the blower 104 is stored, and the other end of the first circulation duct 105 is connected to the ceiling chamber 1.
01A. The other end of the second circulation duct 106 is connected to the other side of the chamber 104A, and the other end of the second circulation duct 106 is opened into the underfloor chamber 101C.

[0006] One end of an air supply duct 107 is connected to an intermediate portion of the first circulation duct 105, and an outside air conditioner 108 is connected to the other end of the air supply duct 107.

[0007]

However, the ultimate goal of cleanliness management is the clean room 101B.
The cleanliness in the clean room 101B has been evaluated based on the dust concentration in the atmosphere, although it should be controlled by the dust concentration attached to the components such as semiconductors produced in the above.

In the clean room 101B, it is required to freely adjust the cleanliness of the clean room 101B in response to a request for an investigation of the relationship between the dust concentration in the atmosphere and the dust concentration attached to components such as semiconductors. It was difficult to control the degree freely.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a clean room cleanliness control device capable of freely controlling cleanliness in a clean room. .

[0010]

SUMMARY OF THE INVENTION The present invention provides a clean room, a ceiling chamber adjacent to the clean room, to which clean air is blown to the clean room, and a clean air blown from the clean room, adjacent to the clean room. An intake duct that takes in outside air containing a lot of dust
And underfloor chamber formed bets on one side, it is installed outside the clean room, a blower for blowing air in the underfloor chamber, a first air duct having one end connected to the blower, the first
A first branch duct and a second branch duct branched and connected to the other end of the blower duct; a first airflow adjustment damper and a high-performance filter provided in the middle of the first branch duct;
A second air volume adjustment damper provided in the middle of the branch duct;
A second air duct, one end of which joins at the junction of the first branch duct and the second branch duct and the other end of which opens into the ceiling chamber ;
A cleanness sensor that measures cleanliness, and in the middle of the intake duct
Measured by an interposed intake air amount adjustment valve and a cleanliness sensor
Compare the specified air cleanliness with the target cleanliness and
By adjusting the opening of the flow control valve to adjust the intake air volume,
In addition, the opening degree of the first air volume adjustment damper and the second air volume adjustment damper
Adjust and bring measured air cleanliness closer to target cleanliness
And control means .

[0011]

According to the present invention, a high dust concentration outside air is purified by preparative
The air is taken into the underfloor chamber from the inlet duct, and a part of the outside air is guided to the first branch duct by the blower, and
The air volume is adjusted by the air volume adjustment damper, and the air is purified by the high-performance filter to become clean air. For cleanliness sensor
The cleanliness in the clean room is measured.

On the other hand, another part of the outside air (air having a high dust concentration) is led to the second branch duct, where the air volume is adjusted by the second air volume adjustment damper, and then mixed with the clean air at the junction. And a predetermined dust concentration value is obtained.

That is, the outside air containing a large amount of dust passes through the first branch duct, and its air volume is adjusted by the first air volume adjusting damper, and is also cleaned by the high-performance filter. The air volume passing through the second branch duct is adjusted by the second air volume adjustment damper and mixed with the outside air containing much dust. The mixed clean air flows out to the ceiling chamber through the second ventilation duct, and is further guided to the clean room, where the cleanliness in the clean room is set to the target as follows.
Close to cleanliness. The cleanliness sensor is controlled by the control means.
The measured air cleanliness is compared with the target cleanliness.
The opening of the intake air amount adjustment valve is adjusted, and the intake air amount
Is adjusted, the first air volume adjustment damper and the second air volume adjustment
The damper opening is adjusted and the measured air cleanliness is
It approaches the standard cleanliness.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a clean room cleanliness control apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a clean room comprising a booth, and a ceiling chamber 2 in which clean air is blown to the clean room 1 adjacent to the clean room 1,
It is installed via a ceiling 3 having many outlets 3A.

An underfloor chamber 4 to which clean air is blown from the clean room 1 is installed adjacent to the clean room 1 via a floor 4B having a large number of suction holes 4A. Is provided on one side. An intake duct 5A is connected to the intake port 5, and a high-precision intake air amount adjusting valve 5B is interposed in the middle of the intake duct 5A.

Reference numeral 6 denotes a blower, which is installed in the underfloor chamber 4 outside the clean room 1 and blows clean air and outside air containing much dust in the underfloor chamber 4. One end of a first air duct 7 is connected to the blower 6, and the other end of the first air duct 7 is branched into a first branch duct 8 and a second branch duct 9.

In the middle of the first branch duct 8, a first air volume adjusting damper 10 and a high-performance filter 11 are disposed downstream of the first air volume adjusting damper 10. Also, the second
A second air volume adjusting damper 12 is interposed in the branch duct 9.

The first branch duct 8 and the second branch duct 9 are
It joins at a junction 13 composed of an air-mixing box. One end of a second air duct 14 is connected to the junction 13, and the other end is open into the ceiling chamber 2.

Thus, in this embodiment, outside air containing a large amount of dust and having a high dust concentration is taken into the underfloor chamber 4 from the intake port 5, and a part of the outside air is blown by the blower 6 to the first branch duct 8. The air volume is adjusted by the first air volume adjustment damper 10 and the high-performance filter 11
Thus, the air is purified and becomes clean air containing almost no dust.

On the other hand, another part of the outside air (air containing a large amount of dust and having a high dust concentration) is led to the second branch duct 9,
After the air volume is adjusted by the second air volume adjustment damper 12, the air is guided to the junction 13. In the junction 13, clean air containing almost no dust and air containing dust in the second branch duct 9 are mixed to have a predetermined dust concentration.

That is, the outside air containing much dust passing through the first branch duct 8 is adjusted in its air volume by the first air volume adjusting damper 10 and is cleaned by the high-performance filter 11.
The purified clean air is supplied to the second air volume adjusting damper 12.
Thus, the amount of air passing through the second branch duct 9 is adjusted and mixed with the outside air containing much dust. The mixed clean air flows out to the ceiling chamber through the second ventilation duct 14, and is further guided to the clean room 1, and the cleanliness in the clean room 1 is reduced to a predetermined value by the control means . Is controlled as follows.

[0023] The target cleanliness as a predetermined value in the clean room 1 and C _r. First, incoming air cleanliness C _i taken of intake air in the intake duct 5A is measured. And the intake air cleanliness C _i, based on the target cleanliness C _r, the target cleanliness C _r, intake air quantity Q _i, associated tables airflow Q ₃ which passes through the second branch duct 9 (described later calculations Approximately calculated by the formula)
From the opening of the intake air amount adjusting valve 5B is adjusted, intake air amount Q _i is set.

Then, the first air volume adjusting damper 10 and the second air volume
The opening of the quantity adjustment damper 12 is adjusted, and the first branch duct 8 is adjusted.
Air volume Q passing through_TwoAnd the wind passing through the second branch duct 9
Quantity Q _ThreeIs set.

For example, the intake air amount Q _i = 3530,00
0 / m ³ , air volume Q ₂ : air volume Q ₃ = 1: 99, the actual cleanliness in the clean room 1 having a value close to the target cleanliness C _r = 353,000 cores / m ³ becomes clean. It is measured by the degree sensor 15. The control unit, the measured cleanliness values and target cleanliness C _r are compared, by adjusting the opening degree of the intake air amount adjusting valve 5B manually, with fine adjustment of the intake air quantity Q _i , a first flow rate control damper 10 the opening of the second air flow control damper 12 is manually adjusted, the value of the measured cleanliness is brought close to the target cleanliness C _r.

Here, the cleanliness in the clean room 1 is reduced.
In order to maintain the constant, it is necessary to constantly take in air having a high dust concentration from the intake 5. this is,
Dust containing specific components such as oil mist and metal powder is generated from the rotating device of the blower 6, and the dust containing such specific components alone may lose general dust behavior. In order to prevent this, air having a high dust concentration including dust is constantly taken in from the intake port 5 so that a specific dust generation influence is not exerted.

[0027] Then, the air cleanliness in the clean room 1 reaches the target cleanliness C _r is schematically estimated by the following equation as a model the flow of air shown in FIG. The degree of air cleanliness in the clean room 1 is determined by measuring the number of particles per unit space using, for example, a laser.
It is expressed in units of t ^{3 or} co / m ³ .

[0028] Here, C _r: cleanroom target cleanliness [co / m ^3] [10,000 U / ft ³ = 353,000 U / m ^3] C _i: intake air cleanliness [co / m ³ ] [100,000 ko / ft ³ = 3530,000 ko / m
^3] Q _r: return air amount [m ³ / H] [999m ³ / H] Q _i: intake air amount [m ³ / H] [1 m ³ / H] G: in-situ dust [co / m ³ ] [10,000 U / H] C _r ': return air cleanliness [co / m ^3] C _1: intake air cleanliness C _i and return air cleanliness C _r' admission cleanliness [U / m ³ ] Q ₂ : Air volume of the first branch duct Q ₃ : Air volume of the second branch duct η: (1−dust removal efficiency) ≒ 0, _Cr ′ = (G + _Cr × _Qr ) / _Qr = (10,000 pieces / H + 353,000 pieces / m ³ × 999 m ³ / H) / 999 m ³ / H = 353,400 pieces / m ³ C ₁ = (C _i × Q _i + C _r '× Q _r ) / ( _{Q i + Q r) = (} 353,000 × 1 + 353,400 × 999) / 1000 = 356,600 U _{^{/ m 3 C r = (C}} 1 × η × Q 2 + C 1 × Q 3) / (Q 2 + Q 3 ) = 356,600 × Q _3/1 00 (η ≒ 0) = 353,000 U / m ^{3 _{Therefore, Q 3 = 990m 3 / H}} , Q 2: Q 3 = 10: 9
90 = 1: 99, the target cleanliness C in the clean room
_In order to secure _r , the air volume Q ₂ : air volume Q ₃ = 1: 99
(Adjustment of the opening of the first air volume adjustment damper 10 and the second air volume adjustment damper 12).

According to the above-described configuration, the outside air containing a large amount of dust passing through the first branch duct 8 is adjusted by the first air volume adjusting damper 10 and is cleaned by the high-performance filter 11. The purified clean air is mixed with the outside air containing a large amount of dust by adjusting the air volume passing through the second branch duct 9 by the second air volume adjusting damper 12, and the first air volume adjusting damper 10 and the second air volume adjusting damper 12 are mixed. By adjusting the degree of opening and closing, the cleanliness in the clean room 1 can be freely controlled to a predetermined value.

In this embodiment, first, the first
And air flow rate adjusting damper 10 the opening of the second air flow control damper 12 is manually adjusted, furthermore, the measured cleanliness values and target cleanliness C _r are compared, a manual intake air control valve 5B by adjusting the opening, as well as fine adjustment of the intake air quantity Q _i, the first flow rate control damper 10 second air flow control damper 12
Opening was adjusted manually, the value of the measured cleanliness is brought close to the target cleanliness C _r, it is also possible to automatically control their a series of operations.

[0031]

As described above, according to the present invention,
The outside air containing much dust passes through the first branch duct,
The air volume is adjusted by an air volume adjustment damper, and the air is cleaned by a high-performance filter.
The air volume passing through the second branch duct is adjusted by the air volume adjustment damper, mixed with the outside air containing much dust, and the opening / closing degree of the first air volume adjustment damper and the second air volume adjustment damper is adjusted, so that the cleanness in the clean room is improved. Can be freely controlled to a predetermined value.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a clean room cleanliness control device according to an embodiment of the present invention.

FIG. 2 is an explanatory view of an operation state of the clean room cleanliness control device.

FIG. 3 is a side view showing a conventional clean room.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Clean room 2 Ceiling chamber 4 Underfloor chamber 5 Inlet 7 1st ventilation duct 8 1st branch duct 9 2nd branch duct 10 1st air volume adjustment damper 11 High performance filter 12 2nd air volume adjustment damper 13 Merging part 14 2nd air duct

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F24F ^7/ 04-7/06

Claims (1)

(57) [Claims] 1. A clean room, a ceiling chamber adjacent to the clean room, through which clean air is blown to the clean room, and a clean air blown from the clean room adjacent to the clean room, and the outside air containing a large amount of dust. An underfloor chamber having an intake duct formed on one side, a blower installed outside the clean room to blow air in the underfloor chamber, a first blower duct having one end connected to the blower, and a first blower duct. At the end, a first branch duct and a second branch duct branched and connected, a first airflow adjustment damper and a high-performance filter provided in the middle of the first branch duct, and a middle branch of the second branch duct. A second airflow adjusting damper, a second branch duct having one end joined at a junction of the first branch duct and the second branch duct and the other end opened into the ceiling chamber. And wind duct, cleanliness of the clean room provided in a clean room
Sensor for measuring air purity, intake air amount adjustment valve interposed in the intake duct, air cleanliness measured by the cleanness sensor and target cleanliness
And adjust the opening of the intake air amount adjustment valve to take in the intake air.
In addition to adjusting the air volume, the first air volume adjustment damper and the second air volume
Adjust the opening of the damper and adjust the measured air cleanliness.
And a control means for approaching the target cleanliness level .