JPH05240477A - Purifying method and device therefor - Google Patents

Abstract

PURPOSE:To carry out higher grade purification by a method wherein a gas resistant body is provided below the putting area of substances to be purified and an exhausting means is provided below the gas resistant body, in a device preventing the adhesion of particles to the substances to be purified by forming downward purifying airstream around the periphery of the substances to be purified. CONSTITUTION:In cleaning system of wafers, treated through CVD treatment, four sets of ventilating devices 2A-2D are arranged in one row along the transfer passage L of a transferring carrier C, in which the wafers are received, while a stocker S1 for the transferring carrier C and another stocker S2 for a cleaning carrier are provided so as to pinch the upper area of the transfer passage of the carrier from the upper part of the transferring passage L. Respective ventilating devices 2A-2D are constituted of a suction fan 4 and an ULPA filter 5, which are provided in a casing body 3 provided with a multitude of ventilating holes 3a on the upper and lower surfaces thereof. A gas resistant body or another ULPA filter 6 is arranged below the transferring passage L through a space SP while a plurality of exhaust fans 7 are arranged on the lower surface of the same and an exhaust chamber 71 is formed on the lower side of the exhaust fans 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for obtaining a clean atmosphere when, for example, a semiconductor wafer is housed in a carrier and transported or stored.

[0002]

2. Description of the Related Art When handling semiconductor wafers,
It is necessary to take measures to suppress the adhesion of particles to the wafer as much as possible.Therefore, in transporting and storing the carrier that contains the wafer, or transferring the wafer, pay attention not only to each operation but also to the work atmosphere. Alternatively, the storage atmosphere must be cleaned.

Therefore, conventionally, for example, a filter is arranged on the ceiling of a room to form an air intake chamber above the filter, and a wire mesh is laid on the floor of the room to reach the air intake chamber from the bottom. A ventilation passage for circulation is formed, and by operating the circulation fan in this ventilation passage, air is circulated through the ventilation passage, while forming a downward flow (downflow) from the ceiling to the floor surface, which is clean. I try to get the atmosphere. If, for example, a carrier containing a wafer is transported in such a room, particles generated by the transportation of the carrier can be placed in a downward flow and discharged from the transportation region.

[0004]

By the way, since the integration of semiconductor devices is further advanced, and the capacity of DRAMs is increased from 1M to 4M and 16M, the atmosphere for handling wafers is further enhanced. Cleaning is required.

On the other hand, in order to clean the wafer and the carrier for transfer, the wafer is transferred between the carrier for transfer and the carrier for cleaning, or the carrier is transferred between the transfer path and the stocker (storage area). There is a case where a system in which the wafer and the carrier make complicated movements is assembled, but in such a system, the mechanisms for carrying and transferring are closely arranged, so that the complicated movements of the wafer and the carrier are caused. Alternatively, there is a problem that the amount of dust is increased and the air flow is disturbed due to the operation of each mechanism in close contact with each other, which causes a vortex and the like, and particles are not sufficiently discharged from the work area.

Further, as the number of transporting and transferring mechanisms increases and the number of carriers to be moved at one time increases, the size of each mechanism increases, and along with that, a power source unit such as a control power source, a controller, a printed circuit board or a motor driver. However, as a result, the amount of heat generated by the power supply unit also increases, and it is now at a level at which it is necessary to consider both the cleaning measures and the effect of the air flow due to this heat generation.

The present invention has been made under such circumstances, and an object thereof is to improve the cleaning of the atmosphere around a carrier or the like containing a semiconductor wafer when the carrier or the like is stored or transferred. It is in.

[0008]

According to a first aspect of the present invention, there is provided an apparatus for forming a downward clean air flow around an object to be cleaned to prevent particles from adhering to the object to be cleaned. A gas resistor is provided on the lower side of the placing region so as to face the placing region, and gas is allowed to flow from the upper surface side to the lower surface side of the gas resistor on the lower surface side of the gas resistor to exhaust gas downward. It is characterized in that an exhaust means is provided.

According to a second aspect of the present invention, there is provided a method for preventing particles from adhering to an object to be cleaned by forming a downward clean air flow around the object to be cleaned conveyed along the object to be cleaned. It is characterized in that the airflow reaching the lower side is discharged to the outside without being circulated, and a power supply unit of the transfer system is arranged on the lower side of the transfer path.

[0010]

Since the air resistor is provided on the exhaust means, the negative pressure region generated by the operation of the exhaust means spreads along the lower surface of the air resistor. Therefore, the air on the upper surface side of the air resistor is not locally sucked, but is sucked over the entire area, and becomes a downward laminar flow without disturbance. In addition, when the product to be cleaned is transported, the power supply unit is placed on the lower side of the transport path, and even if convection occurs due to the large heat generation amount of the power supply unit by discharging the air flow from the lower side to the outside, the air flow near the transport path Disturbance does not occur.

[0011]

EXAMPLE An example in which the present invention is applied to a cleaning system for cleaning a wafer and a carrier will be described below. First, before describing the cleaning of air, the entire cleaning system will be briefly described with reference to FIG.

Reference numeral 100 is a carry-in stage, for example, a CV
The carrier C for carrying the wafer W that has undergone D processing is carried from here to the outside. The carrier C placed on the carry-in stage 100 is transferred to the transfer unit 101 and flows into the cleaning system from here. Further, 102 is a carry-out stage, which is a carrier C sent from the cleaning system.
Are placed here via the transfer unit 101. Transfer of the carrier C between these is performed by the interface robot IF.
Done by

Reference numeral 103 denotes a carrier carrier elevator having an arm, which stores the carrier C received via the transfer section 101 in a stocker (not shown),
The carrier C stored in the stocker is indirectly transferred to the transfer robot 104. This transfer robot 10
4 transfers the carrier C to the moving stage 105 or transfers the reverse thereof.

On the moving stage 105, the uncleaned wafer is transferred from the carrier C for cleaning to the carrier D for cleaning by the cooperation of the upper holding arm 106 and the lower push-up means (not shown). The cleaned wafer is transferred from the cleaning carrier D to the transfer carrier C.

The carrier C for transfer separated from the wafer is sent to the carrier cleaning section by one of the transfer paths L1 and L2 and returned by the other transfer path after cleaning.
The cleaned wafer is stored.

Reference numeral 107 denotes a cleaning elevator equipped with an arm, which is a cleaning carrier D on the moving stage 105.
Is stored in a stocker (not shown), and the cleaning carrier D stored in the stocker is delivered to the output port 108 to the cleaning processing unit. In this way, in the system of FIG. 1, the transfer carrier and the wafer are separated and cleaned separately, and after cleaning, the transfer robot 10 and the transfer robot 10 are combined again.
4 and the carrier carrier elevator 103 for conveyance, and is sent out to the carry-out stage 102.

Next, a cleaning device according to an embodiment of the present invention and a cleaning method using this device will be described. 2 and 3 are views showing a cleaning device combined with the cleaning system shown in FIG. 1, and are views of the cleaning system of FIG. 1 as seen from the side and the front, respectively. However, the carrier elevators 103 and 107 are omitted.
In the figure, L is a carrier path for a carrier that accommodates wafers to be cleaned, and is specifically a carrier path member such as a mounting table and a moving stage, but is schematically shown for convenience. Above the transport path L, four air supply devices 2A to 2D are arranged in line along the transport path L. Above the transport path L, the empty carrier transport path L1 of FIG.
A stocker S1 of the carrier C for transporting and a stocker S2 of the carrier D for cleaning are installed across the upper region of L2.
1, located below S2. And stocker S1
The air supply device 2B on the lower side of the other air supply devices 2A, 2C, 2
Although located lower than D, each of the air supply devices 2A-2
D is arranged so as to be connected to each other when viewed from above, so that the air directly above the transport path L is fed to the air supply devices 2A to 2D.
You will pass either.

Each of the air supply devices 2A to 2D is provided with an enclosure 3 having a large number of ventilation holes 31 formed on the upper surface or side surfaces (left and right side surfaces in FIG. 3) and lower surface thereof, and the upper surface or It is formed by a suction fan 4 for sucking air from the side surface and, for example, a ULPA filter 5 arranged on a group of ventilation holes on the lower surface of the case 3.

Below the carrier transfer path L, a space S
A ULPA filter 6 as, for example, a gas resistor (in this case, an air resistor) is disposed so as to face the transport path L via P, and the lower surface side of the filter 6 is connected to the transport path L. A plurality of, for example, three exhaust fans 7 as exhaust means are provided along the line.

An exhaust chamber 71 communicating with the outside is formed below the exhaust fans 7, and the exhaust fan 7 is mounted and fixed on the upper surface of the exhaust chamber 71. The upper surface of the exhaust chamber 71 has a vent hole 72 formed only in a region facing the exhaust surface of the exhaust fan 7. Therefore, the air in the space SP below the transport path L is exhausted through the exhaust fan 7. It enters the chamber 71 and is discharged to the outside.
Note that frame plates are provided on both sides of the space SP (front and back sides in FIG. 2), for example, to suppress the inflow of airflow from both sides so as not to disturb the airflow downward from the transport path L. ..

Further, the elevators 103 and 107, the transfer robot 104, the transfer mechanism such as the wafer pushing-up means, the transfer mechanism and the like have a control power source, a controller, a printed board, a motor driver and the like. One unit or a plurality of units are integrated as a unit. In this embodiment, such a power supply unit 8 is provided in a space SP on the lower side of the transport path L, for example, at two locations on the inlet side of the transport path L and near the intermediate portion. is set up.

Next, the operation of the above embodiment will be described. When the suction fan 4 of each of the air supply devices 2A to 2D is operated, air is sucked into the cell 3 through the ventilation hole 31 on the upper surface of the cell 3, and the air is cleaned through the filter 5 to It descends by the ventilation hole 31 of 3.

On the other hand, when the exhaust fan 7 is operated, the air on the upper surface side of the filter 6 is removed by the filter 6 and the exhaust fan 7.
The exhaust gas passes through the inside of the exhaust chamber 71 and is discharged to the outside. However, since the filter 6 on this is an air resistor, the negative pressure region generated by the exhaust fan 7 spreads along the lower surface of the filter 6, Therefore, the air on the upper surface side of the filter 6 is not locally sucked, but is sucked over the entire surface of the filter 6.

Here, the power supply unit 8 is a heat source, and in this example, since two carriers are simultaneously carried, the power of the power supply unit 8 is large and the amount of heat generation is large.
Since it is arranged on the lower side of the transport path L, the air warmed by heat generation does not flow in the transport path L, so that the air flow in the transport path L is not disturbed. Therefore, a downward laminar flow without turbulence such as retention or vortex is formed in the region surrounding the transport path L, together with the generation of the downward flow by the air supply devices 2A to 2D. As a result, particles generated by carrier transportation and transfer are sucked into the filter 6 and removed,
The transport path L maintains a clean atmosphere.

In the above embodiment, the rotation speed of the suction fan 4 or the exhaust fan 7 is adjusted by adjusting the rotational speed of the suction fan 4 or the exhaust fan 7 in accordance with the positional relationship between the air supply devices 2A to 2D and the exhaust fan 7 and the layout of the transfer mechanism. An optimum air flow can be formed, and the thickness of the filter 6 can be changed, for example, between the portion directly above the exhaust fan 7 and another portion according to the number of the exhaust fans 7 and the exhaust capacity. By devising it, the turbulence of the downward laminar flow can be further suppressed.

In order to clean the periphery of the transport path, for example, the upper space of the transport path is divided into a plurality of parts by partition plates, and an air supply device is installed in each divided area as in the embodiment, and a shutter is provided under the partition plate. By providing a method of opening and closing the shutter in accordance with the timing of conveyance, it is possible to further suppress the turbulence of the downward laminar flow.

In the present invention, the power supply unit 8 may be arranged outside the area where clean air is flowing.
If it is provided on the lower side of the transport path as in the embodiment, it is advantageous because it is not necessary to secure a dedicated installation space.

In the present invention, the object to be cleaned is not limited to wafers and carriers, but can be applied to the storage of medical instruments and the like, and the gas for cleaning is limited to air. Instead, it may be an inert gas or the like.

In the above-described embodiments, an example in which the present invention is applied to a cleaning system has been described. However, the present invention is intended to temporarily store unprocessed semiconductor wafers and processed semiconductor wafers in a carrier. It can also be applied to the stock device.

[0030]

According to the first aspect of the present invention, since the exhaust means exhausts air below the area where the object to be cleaned is placed, for example, through the air resistor, the negative pressure area by the exhaust means is air. It spreads along the lower surface of the resistor and is sucked over the entire surface of the filter without being sucked locally. Therefore, even if the mechanisms for carrying and transferring are closely attached, or even if there are many carrier paths for carriers, for example, a laminar flow without turbulence such as vortex or retention is formed without being greatly affected by these. Therefore, the particles generated by transportation or the like are reliably discharged from the area where the substance to be cleaned is placed, so that a clean atmosphere can be maintained.

According to the second aspect of the present invention, in order to clean the conveying path by the downward airflow, the power supply unit of the conveying system is arranged on the lower side of the conveying path, and the airflow is not circulated to the outside. Therefore, even if the heat generation amount of the power supply unit is large, the turbulence of the air flow does not occur near the conveyance path. On the other hand, when the power supply unit is arranged above the transport path or when the airflow is circulated, convection due to heat generation of the power supply unit occurs above the transport path and the downward airflow is disturbed, resulting in vortex flow. And retention occurs. Therefore, according to the second aspect of the present invention, it is possible to sufficiently purify, for example, the air in the vicinity of the conveyance path, and in the case where a power supply unit of the conveyance system is separately installed outside the air flow, a wasteful space is required. Since it can be stored under the road, it is particularly effective when the transport mechanism or the like is complicated or becomes large.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an entire cleaning system to which an embodiment of the present invention is applied.

FIG. 2 is a side view schematically showing an embodiment of the present invention.

FIG. 3 is a front view schematically showing an embodiment of the present invention.

[Explanation of symbols]

 2A to 2D Air supply device 3 Body 4 Suction fan 5 Filter 6 Filter as air resistor 7 Exhaust fan 8 Power supply unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hirofumi Shiraishi, 2655 Tsukyu, Kikuyo-machi, Kikuchi-gun, Kumamoto Prefecture, Tokyo Electron Kyushu Co., Ltd. Co., Ltd. (72) Inventor Takayuki Tomoeda 2655 Tsukyu, Kikuyo-cho, Kikuchi-gun, Kumamoto Prefecture Tokyo Electron Kyushu Co., Ltd.

Claims (2)

[Claims] 1. An apparatus for forming a downward clean air flow around a substance to be cleaned to prevent particles from adhering to the substance to be cleaned, wherein the mounting region is below the mounting region of the substance to be cleaned. A cleaning method characterized in that a gas resistor is provided facing each other, and an exhaust means for sucking gas from the upper surface side to the lower surface side of the gas resistor and exhausting it downward is provided on the lower surface side of the gas resistor. apparatus. 2. A method for preventing particles from adhering to an object to be cleaned by forming a downward clean air flow around the object to be cleaned which is conveyed along the object to be cleaned. A cleaning method, characterized in that an airflow is discharged to the outside without being circulated, and a power supply unit of a transfer system is arranged below a transfer path.