JPH1012585A - Closed type wafer-cleaning equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable closing with low pressure, simplify and miniaturize structure, reduce the generation of particles, and make periodical exchange at the time of maintenance unnecessary, by installing a closing upper lid on an outer tank which closes a cleaning tank, via the sealing liquid of the outer tank. SOLUTION: A cleaning equipment consists of a cleaning tank 1, an outer tank 2 installed on the outer periphery of the cleaning tank 2, and a closing upper lid 3 which is installed on the outer tank 2 and closes the cleaning tank 1. The lower aperture 3b of the upper lid 3 is a slightly larger than the upper part aperture 1a frame, and a slightly smaller than the upper aperture 2a of the outer tank 2. The closing upper lid 3 is rectangular and made of plastic or the like, similarly to the cleaning tank 1 and the outer tank 2. The upper lid 3 is installed on the outer tank 2, via sealing liquid which is accommodated in the outer tank 2. Thereby the outer tank 2 and the closing upper lid 3 are subjected to liquid sealing by the sealing liquid, interposed between them, and the cleaning tank 1 is closed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a closed type wafer cleaning apparatus for cleaning a wafer in a closed tank. More specifically, the present invention relates to a closed-type wafer cleaning apparatus for supplying a cleaning liquid into a bath in which a wafer such as a semiconductor wafer is closed and cleaning the wafer.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, cleaning for removing stains on the surface of a wafer (mirror surface of a wafer) with a cleaning liquid is performed because various processes are performed. When it is necessary to clean a wafer with high accuracy, a closed-type wafer cleaning apparatus for cleaning a wafer in a closed tank is used.

A conventional closed-type wafer cleaning apparatus employs a method in which an elastic body (rubber or the like) is interposed between a cleaning tank and a sealing upper lid to mechanically apply pressure to keep the cleaning tank and the sealing upper lid tightly closed. You.

[0004]

However, the conventional closed-type cleaning apparatus needs to sufficiently withstand high pressure and mechanical external force, and has a problem that it is structurally complicated and large in size. Further, since there is a mechanical sliding portion, particles are generated, which adversely affects the wafer. In addition, since the seal portion is made of an elastic material (rubber or the like), dust adheres, scratches, and the like occur, which requires periodic replacement at the time of maintenance, which is disadvantageous in terms of work surface and cost.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and enables a hermetic seal at a low pressure, has a simple structure and can be miniaturized, generates little particles, and is regularly replaced during maintenance. It is an object of the present invention to provide a closed-type wafer cleaning apparatus that does not require any other means.

[0006]

In order to achieve the above object, the present invention provides a cleaning tank containing a cleaning liquid for cleaning a wafer, and an outer tank provided on the outer periphery of the cleaning tank for storing a sealing liquid. A sealed wafer cleaning apparatus comprising: a sealing upper lid provided on an outer tank for sealing a cleaning tank via a sealing liquid of the outer tank.

[0007]

In a preferred embodiment, the cleaning tank is provided with a cleaning liquid supply pipe for supplying a cleaning liquid and a cleaning liquid discharge pipe for discharging the cleaning liquid at a lower portion of the cleaning tank, and the cleaning liquid discharge pipe and the cleaning liquid supply pipe. Are connected by a circulation line, a circulation pump that circulates the cleaning liquid through the circulation line, and a filter that filters the cleaning liquid, wherein the outer tank is provided with a sealing liquid supply pipe for supplying a sealing liquid to a lower portion of the outer tank and a sealing liquid. A seal liquid discharge pipe for discharging is attached.

Further, in a preferred embodiment, the outer tank is provided with a cleaning liquid supply pipe for supplying a cleaning liquid also serving as a sealing liquid at a lower portion of the outer tank, and the cleaning tank is provided with a cleaning liquid also serving as a sealing liquid from the outer tank. An upper opening of the overflowing cleaning tank is provided at a position lower than an upper opening of the outer tank, and a cleaning liquid discharge pipe for discharging a cleaning liquid also serving as a sealing liquid is attached to a lower part of the cleaning tank, and the cleaning liquid discharge pipe and the cleaning liquid are provided. The supply pipe is connected by a circulation line, and the circulation line is provided with a buffer tank for mixing a medicine and pure water to produce a cleaning liquid also serving as a sealing liquid, a circulation pump for circulating the cleaning liquid, and a filter for filtering.

Further, in a preferred embodiment, the closed upper lid is provided with a fluid supply pipe for supplying a fluid and a fluid discharge pipe for discharging the fluid above the closed upper lid. Further, in a preferred embodiment, the cleaning tank is provided with a mega device at a lower central portion in the cleaning tank. Further, in a preferred embodiment, the cleaning tank is provided with a perforated plate at a lower portion in the cleaning tank.

Further, in a preferred embodiment, the cleaning tank is characterized in that a carrier support is provided in the cleaning tank, and a carrier holding a plurality of wafers is supported on the carrier support. Further, in a preferred embodiment,
In the cleaning tank, a wafer support is provided in the cleaning tank, and a wafer is supported on the wafer support.

[0011]

1 and 2 show an embodiment of a closed type wafer cleaning apparatus according to the present invention. FIG. 1 is a sectional view of the apparatus, and FIG. 2 is a plan view of the apparatus.

The closed type wafer cleaning apparatus of the present invention comprises a cleaning tank 1, an outer tank 2 provided on the outer periphery of the cleaning tank 1, and a closed upper lid 3 for sealing the cleaning tank 1 provided on the outer tank 2. Have been. The cleaning tank 1 is formed of a rectangular container made of, for example, plastic and having an upper opening 1a for accommodating the cleaning liquid W. The cleaning tank 1 may be made of a material that is easily broken such as Teflon (trade name), stainless steel, quartz, or the like, in addition to a plastic container.

At an upper position in the cleaning tank 1, a carrier support 6 for supporting a carrier 5 holding a predetermined number of wafers 4 to be cleaned is integrally provided to protrude inward. Therefore, the carrier 5 holding a plurality of wafers 4 is supported by the carrier support 6 protruding inward.

A hole opening plate 7 is provided at a lower position in the cleaning tank 1. Therefore, the cleaning liquid W prepared by mixing a chemical solution (eg, ammonia water, hydrogen peroxide solution) and pure water supplied from the lower bottom portion 1b of the cleaning tank 1 into the tank is supplied to the entire tank evenly. At the position of the center of the cleaning tank 1 on the holed plate 7, that is, at the center of the cleaning tank 1 below the carrier 5, a curved mega device (ultrasonic wave) arranged along the longitudinal axis of the tank. (Cleaning device) 8 is provided. for that reason,
The generated ultrasonic waves promote the cleaning effect of the cleaning liquid W on the wafer 4 and improve the particle removal rate.

A cleaning liquid supply pipe 9 for supplying a cleaning liquid W into the tank is attached to one side of the lower bottom 1b of the cleaning tank 1. The cleaning liquid supply pipe 9 is provided with a valve V1 which opens and closes. On the other side of the lower bottom portion 1b of the cleaning tank 1, a cleaning liquid discharge pipe 10 for discharging the used cleaning liquid W out of the tank is attached, and the cleaning liquid discharge pipe 10 is provided with a valve V2 that opens and closes. I have. The cleaning liquid discharge pipe 10 and the cleaning liquid supply pipe 9 are connected by a circulation line 11,
The circulation line 11 is provided with a circulation pump P for circulating the cleaning liquid W and a filter F for filtering.

Accordingly, when the circulation pump P is driven, the cleaning liquid W flows through the circulation line 11 to the filter F side, is filtered, and the cleaning liquid W purified by the filter F is supplied to the valve V1.
Is supplied into the cleaning tank 1 through the opened cleaning liquid supply pipe 9. On the other hand, the dirty cleaning liquid W used in the cleaning tank 1 is discharged through the cleaning liquid discharge pipe 10 in which the valve V2 is opened, returned to the circulation pump P through the circulation line 11, and thus the cleaning liquid W is circulated. You.

The wafer 4 in the cleaning tank 1 held and accommodated by the carrier 5 is cleaned for a predetermined time by the cleaning liquid W supplied to the cleaning tank 1 through the cleaning liquid supply pipe 9.
In addition, cleaning is performed by ultrasonic waves generated from a mega device (ultrasonic cleaning device) 8 provided in the cleaning tank 1, and the cleaning effect is promoted.

The outer tank 2 is a frame-shaped tank provided on the outer periphery of the cleaning tank 1. On one side of the lower bottom portion 2b of the outer tank 2, a sealing liquid supply pipe 12 for supplying a sealing liquid Wa, for example, pure water, into the outer tank 2 is attached. Is provided. On the other side of the lower bottom portion 2b of the outer tank 2, a seal discharge pipe 13 for discharging the seal liquid Wa in the outer tank 2 is attached, and the seal discharge pipe 13 is provided with a valve V2 that opens and closes. . Therefore, the sealing liquid Wa is supplied into the outer tank 2 from the sealing liquid supply pipe 12 with the valve V1 opened,
On the other hand, the seal liquid Wa in the outer tank 2 is discharged out of the tank from the seal discharge pipe 13 with the valve V2 opened. The cleaning liquid W may be used as the sealing liquid Wa.

The closed upper lid 3 has a lower opening 3b which is slightly larger than the frame of the upper opening 1a of the cleaning tank 1, and which is slightly smaller than the upper opening 2a of the outer tank 2. A rectangular lid made of a similar plastic or the like is provided on the outer tub 2 via the seal liquid Wa contained in the outer tub 2. Thereby, the outer tank 2 and the sealing upper lid 3 are fluid-sealed with the sealing liquid Wa interposed therebetween, and the cleaning tank 1 is sealed.

In this embodiment, since the tank is sealed with a fluid seal, it is not necessary to apply a high pressure and a mechanical external force as in a conventional seal made of an elastic body (rubber or the like). Therefore, low pressure sealing is achieved, and the structure is simplified and the size can be reduced.

On one side of the upper part 3a of the closed upper lid 3,
Fluid supply pipe 14 for supplying a fluid, for example, nitrogen gas or pure water
The fluid supply pipe 14 is provided with a valve V1 that opens and closes. In addition, a spout 14 a connected to the fluid supply pipe 14 is provided in the closed upper lid 3. On the other side of the upper portion 3a of the closed upper lid 3, a fluid discharge pipe 15 for discharging nitrogen gas and generated exhaust gas in the tank is attached, and the fluid discharge pipe 15 is provided with a valve V2 that opens and closes.

Therefore, nitrogen gas or pure water shower is supplied into the tank from the jet port 14a through the fluid supply pipe 14 with the valve V1 opened, while nitrogen gas and pure water are supplied from the fluid discharge pipe 15 with the valve V2 opened. The generated exhaust gas is discharged out of the tank. Therefore, the air in the bath is replaced with nitrogen gas, and the wafer 4 is washed with water, and dried by supplying nitrogen gas after washing with water to obtain a wafer 4 with less growth of a natural oxide film and less adhesion of particles. The cleaning of the wafer 4 is performed by the following steps. First, the closed upper lid 3 is raised, the upper opening 1a of the cleaning tank 1 is opened, and the carrier 5 holding a predetermined number of wafers 4 is placed and supported on the carrier support 6 in the opened cleaning tank 1.

Next, the valve V1 provided on the seal liquid supply pipe 12 attached to the lower bottom portion 2b of the outer tank 2 is opened to supply the seal liquid Wa, for example, pure water, into the outer tank 2. In this state, the closed upper lid 3 is lowered and set on the outer tank 3 containing the sealing liquid Wa. Since a fluid seal made of the seal liquid Wa is interposed between the closed upper lid 3 and the outer tank 2, the fluid seal is made by the interposed seal liquid Wa,
The upper opening 1 a of the cleaning tank 1 is closed by a closed upper lid 3.

Next, the valve V1 of the fluid supply pipe 14 attached to one side of the sealed upper lid 3 and the valve V2 provided to the fluid discharge pipe 15 attached to the other side are opened, and the fluid supply pipe 14 is closed. Nitrogen gas is supplied into the space tank to replace the air present in the tank. By this replacement, the inside of the tank becomes a nitrogen gas atmosphere. Thereafter, the valve V1 provided in the cleaning liquid supply pipe 9 and the valve V2 provided in the cleaning liquid discharge pipe 10 are opened, and the circulating pump P is driven to send the cleaning liquid W to the filter F for filtration. Filter F
The cleaning liquid W purified by the above is supplied into the cleaning tank 1 to clean the wafer 4 held by the carrier 5. When the cleaning liquid W is supplied, the cleaning liquid W is spread over the entire tank by a large number of holes formed in a hole opening plate 7 provided at the bottom of the cleaning tank 1 and is supplied on average. The wafer 4 is cleaned by the supplied cleaning liquid W. In addition, the mega device 8 provided in the lower central part in the cleaning tank 1 is driven in conjunction with the supply of the cleaning liquid W, and generates ultrasonic waves. The cleaning with the cleaning liquid W and ultrasonic waves is performed for a predetermined time according to the purpose. By this cleaning, the particle removal rate is improved, and the wafer 4 is well cleaned.

After the cleaning, the valve V1 provided in the cleaning liquid supply pipe 9 is closed, and the valve V2 provided in the cleaning liquid discharge pipe 10 is kept open. The cleaning liquid is discharged from the opened cleaning liquid discharge pipe 10. Thereafter, the nitrogen gas supplied into the tank is switched to pure water, a pure water shower is spouted from the spout port 14a through the fluid supply pipe 14, and the wafer 4 is washed with water. After washing with water, the gas is switched to nitrogen gas, and nitrogen gas is ejected from the ejection port 14a to dry the wafer 4. After the wafer 4 is dried, the closed upper lid 3 is raised to open the cleaning tank 1, the carrier 5 holding the wafer 4 is taken out from the opened cleaning tank 1, and a series of cleaning operations is completed. This cleaning is performed without setting the carrier 5 holding the wafer 4 in the cleaning tank 1 until the carrier 5 is taken out of the cleaning tank 1 without contacting the atmosphere (outside air). Good cleaning without growth and no particle adhesion.

Further, since this device is hermetically sealed by a fluid seal using the sealing liquid Wa, it becomes a low-pressure hermetically sealed chain, and the mechanical external force is also reduced. Therefore, the structure can be simplified and the size can be reduced. The tank is made of a material without pressure resistance,
For example, even those made of quartz or the like can withstand sufficiently. In addition, since the seal portion between the cleaning tank 1 and the closed upper lid 3 does not generate dust and scratches as in the case of the conventional elastic rubber, regular replacement is not required at the time of maintenance. Is advantageous.

FIG. 3 shows another embodiment of the closed type wafer cleaning apparatus according to the present invention. In this embodiment, a cleaning liquid for cleaning a wafer is also used as a sealing liquid Wa for sealing, and this is an example in which the cleaning liquid is applied to a single wafer type for cleaning wafers one by one.

The cleaning tank 1 has an upper opening 1a provided at a position lower than an upper opening 2a of an outer tank 2 provided on the outer periphery of the tank. A cleaning liquid supply pipe 16 for supplying a cleaning liquid W also serving as a sealing liquid is attached to a lower bottom portion 2b of the outer tank 2, and the cleaning liquid supply pipe 16 is provided with a valve V1 that opens and closes. Therefore, by opening the valve V1 of the cleaning liquid supply pipe 16, the cleaning liquid W serving as a sealing liquid is supplied into the outer tank 2, and the cleaning liquid W supplied to the outer tank 2 is supplied to the outer tank 2 more than the upper opening 2a of the outer tank 2. The water overflows to the lower cleaning tank 1 and flows into the cleaning tank 1.

On the other hand, a cleaning liquid discharge pipe 17 is attached to the bottom 1c of the cleaning tank 1, and the cleaning liquid discharge pipe 17 is provided with a valve V2 that opens and closes. Cleaning liquid discharge pipe 17
The cleaning liquid supply pipe 16 is connected to the cleaning liquid supply pipe 16 by a circulation line 18.
A buffer tank B for producing a cleaning liquid W by mixing hydrogen peroxide solution) and pure water, a circulation pump P for circulating the cleaning liquid W, and a filter F for filtering are provided. Accordingly, by driving the circulation pump P, the cleaning liquid W is sent to the filter F side and filtered, and the purified cleaning liquid W is supplied to the outer tank 2 through the cleaning liquid supply pipe 16 and overflows from the outer tank 2. The cleaning liquid W thus supplied is supplied to the cleaning tank 1 and contributes to cleaning. On the other hand, the cleaning liquid W that has contributed to cleaning is
The cleaning liquid W is sent to the buffer tank B through the buffer tank B and returned from the buffer tank B to the circulation pump P. Thus, the cleaning liquid W is circulated. The chemical and pure water are taken out of the filled cylinder. On the lower bottom portion 1b in the cleaning tank 1, a wafer support table 19 composed of, for example, three columns 19a is provided.
A notch 19b is formed on the inside at the tip of 9a, and the wafer 4 is held at three points by the notch 19b of each support 19a.

A mega device 8 is provided in the lower central portion of the cleaning tank 1 and performs ultrasonic cleaning together with the cleaning liquid W. A fluid supply pipe 14 is attached to one side of the closed upper lid 3 as in the above embodiment, and a valve V1 that opens and closes the fluid supply pipe 14 is provided. When the valve V1 is opened, nitrogen gas is introduced into the tank. Supplied.
On the other side, a fluid discharge pipe 15 is attached, and the fluid discharge pipe 15 is provided with a valve V2 that opens and closes, and when the valve V2 is opened, nitrogen gas and generated exhaust gas are discharged.

Therefore, the valve V1 provided on the fluid supply pipe 14 is opened, and the valve V1 provided on the fluid discharge pipe 15 is opened.
When 2 is opened, the air in the tank is replaced with nitrogen gas, and the inside of the tank is replaced with nitrogen gas. In this state, if the valve V1 provided in the cleaning liquid supply pipe 16 is opened and the valve V2 provided in the cleaning liquid discharge pipe 17 is opened, the cleaning liquid W is supplied to the outer tank 2 and overflows from the outer tank 2. The cleaning liquid W is supplied into the bath, the wafer 4 supported on the wafer support table 19 overflows, and the cleaning is performed by the cleaning liquid W. A mega device 8 is disposed in the lower central portion of the cleaning tank 1, and the cleaning device W is driven by the mega device 8.
Ultrasonic waves are generated at the same time as the cleaning, and the cleaning is performed, and the same effect as in the above embodiment can be obtained. The buffer tank B
A drain pipe 20 provided with a valve V3 is attached to the lower part of the drain pipe. Thus, by opening the valve V3, it is possible to drain the dirty cleaning liquid W which has been used for a certain period of time.

FIG. 4 shows still another embodiment of the present invention. This embodiment is an example in which the cleaning liquid for cleaning the wafer is replaced with the single wafer type shown in FIG. 3 which also serves as a sealing liquid, and the wafer is held on a carrier (not shown), and the cleaning liquid is applied to a batch type for simultaneously cleaning a plurality of wafers. It is.

In the upper part of the cleaning tank 1, a jet port 14a for nitrogen gas or the like connected to the liquid supply pipe 14 is provided as in FIG. A perforated plate 7 is provided to be supplied. Other configurations are almost the same as those in FIG. 3, and are denoted by reference numerals and description thereof is omitted. Therefore, also in the case of this embodiment, the operation is substantially the same as in FIGS. 1 and 3, and the same effect is exerted.

[0034]

As described above, according to the present invention, a hermetic seal is formed by a fluid seal using a sealing liquid, so that a low-pressure hermetically sealed chain is obtained and mechanical external force is reduced. Therefore, the structure can be simplified and the size can be reduced. Further, the tank can sufficiently withstand even a material formed of a material having no pressure resistance, such as quartz. In addition, since the cleaning tank and the sealing part of the sealed top lid do not generate dust or scratches unlike conventional elastic rubber, periodic replacement is not required during maintenance, which is advantageous in terms of work surface and cost. become.

Further, according to the present invention, since the cleaning is performed without contacting the atmosphere (outside air) from setting the wafer in the cleaning tank to removing the wafer, a natural oxide film grows on the surface of the wafer (mirror surface of the wafer). In addition, there is an effect that the cleaning is performed without particles and the particles are not adhered.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of a closed type wafer cleaning apparatus according to the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a sectional view of another embodiment of the closed type wafer cleaning apparatus according to the present invention.

FIG. 4 is a sectional view of still another embodiment of the sealed wafer cleaning apparatus according to the present invention.

[Explanation of symbols]

1: Cleaning tank, 1a, 2a: upper opening, 1b, 2b: lower bottom, 2: outer tank, 3: sealed upper lid, 4: wafer, 5: carrier, 6: carrier support, 7: open plate, 8: Mega device, 9, 16: cleaning liquid supply pipe, 10, 17: cleaning liquid discharge pipe, 11, 18: circulation line, 12: seal liquid supply pipe,
13: Seal liquid discharge pipe, 14: Fluid supply pipe, 15: Fluid discharge pipe, 19: Wafer support, B: Buffer tank, W: Cleaning liquid, Wa: Seal liquid.

Claims (8)

[Claims] 1. A cleaning tank containing a cleaning liquid for cleaning a wafer, an outer tank provided on an outer periphery of the cleaning tank for storing a sealing liquid, and an outer tank for sealing the cleaning tank via the sealing liquid of the outer tank. A sealed wafer cleaning apparatus, comprising a sealed upper lid provided on a tank. 2. The cleaning tank is provided with a cleaning liquid supply pipe for supplying a cleaning liquid and a cleaning liquid discharge pipe for discharging the cleaning liquid at a lower portion of the cleaning tank, and the cleaning liquid discharge pipe and the cleaning liquid supply pipe are connected by a circulation line. The circulation line includes a circulation pump that circulates the cleaning liquid and a filter that filters the cleaning liquid.The outer tank has a seal liquid supply pipe that supplies a seal liquid to a lower portion of the outer tank and a seal liquid discharge pipe that discharges the seal liquid. The hermetically sealed wafer cleaning apparatus according to claim 1, wherein the apparatus is attached. 3. The outer tank is provided with a cleaning liquid supply pipe for supplying a cleaning liquid also serving as a sealing liquid at a lower portion of the outer tank. The cleaning tank is provided with a cleaning liquid that also serves as a sealing liquid overflows from the outer tank. The upper opening is provided at a position lower than the upper opening of the outer tank, and a cleaning liquid discharge pipe for discharging a cleaning liquid also serving as a sealing liquid is attached to a lower part of the cleaning tank, and the cleaning liquid discharge pipe and the cleaning liquid supply pipe are connected by a circulation line. 2. The hermetic seal according to claim 1, further comprising a buffer tank connected to the circulation line for mixing a chemical and pure water to produce a cleaning liquid also serving as a sealing liquid, a circulation pump for circulating the cleaning liquid, and a filter for filtering. Type wafer cleaning equipment. 4. The sealed wafer cleaning apparatus according to claim 1, wherein the closed upper lid is provided with a fluid supply pipe for supplying a fluid and a fluid discharge pipe for discharging the fluid above the closed upper lid. . 5. The sealed wafer cleaning apparatus according to claim 1, wherein a mega device is provided in a central portion of a lower portion of the cleaning tank. 6. The closed type wafer cleaning apparatus according to claim 1, wherein the cleaning tank has a perforated plate provided in a lower portion of the cleaning tank. 7. The sealed wafer according to claim 1, wherein the cleaning tank has a carrier support in the cleaning tank, and the carrier supports a carrier holding a plurality of wafers. Cleaning equipment. 8. The sealed wafer cleaning apparatus according to claim 1, wherein the cleaning tank has a wafer support provided in the cleaning tank, and the wafer is supported on the wafer support.