KR100593672B1 - Wafer cleaning equipment - Google Patents

Abstract

A wafer cleaning apparatus is disclosed which sprays washing water uniformly over the entire surface of the wafer during wafer cleaning. The inner tub of the cleaning apparatus is provided with a pipeline extending along both lower sides of the wafer contained therein and a pipeline extending along the lower end of the wafer. A jet port is formed in each pipeline to spray the washing water toward the wafer. A downwardly oriented spout is formed in the pipeline passing through the lower part of the wafer, and the washing water sprayed through the wafer flows along the pair of guides provided at the bottom of the inner tank to the direction of the flat zone of the wafer. Thereby intensively washing the flat portion area. Unevenness of the washing water spray can be prevented, thereby reducing process defects due to the washing variation.

Description

Wafer Cleaning Device {WAFER WASHING APPARATUS}

1 is a cross-sectional view of a wafer cleaning apparatus according to the prior art.

FIG. 2 is a schematic diagram of a conventional Deionized Water bath to account for cleaning irregularities in the flat zone portion of the wafer during wafer cleaning. FIG.

3 is a schematic diagram of a wafer cleaning apparatus according to one embodiment of the present invention;

<Description of Symbols for Main Parts of Drawings>

200: wafer cleaning device

210, 220: inner tank, outer tank 230: first pipe line

235: first outlet 240: second pipe line

245: second outlet 250; Guides

260: pump 270: filter

280: heater W: wafer

TECHNICAL FIELD The present invention relates to a wafer cleaning apparatus, and more particularly, to a wafer cleaning apparatus capable of reducing process defects by allowing a wafer to be uniformly cleaned over its entire surface.

Semiconductor devices are becoming more and more integrated, and their circuit patterns are being refined to submicron units. Moreover, the diameter of the wafer is getting larger. Thus, wafer yields drop significantly even when a small amount of particles that are typically negligible adhere to the wafer surface. To overcome this, a process is performed in which the wafer is immersed in an acid and alkaline solution in a processing bath to wash its surface.

This type of wafer surface cleaning / cleaning system includes an automatic cleaning system, which includes a plurality of processing baths, a space where wafers are cleaned / cleaned by chemical solution and water and dried by heat. More specifically, the system includes an ammonia treatment tank, a water washing tank, a rinsing tank, an acid treatment tank, and a drying chamber. Through such a series of baths, impurities on the wafer surface, natural oxide films, chemical impurities, and the like are removed.

1 shows a chemical solution bath of a "PROCESSING VESSEL FOR A WAFER WASHING SYSTEM" disclosed in US Pat. No. 5,327,921. Referring to FIG. 1, the chemical solution tank 7b includes a main bath portion 34 and an overflow bath portion 37. The overflow bath 37 is formed along the top of the casting 34 and functions to receive a chemical solution that overflows from the casting 34. A port 49 is formed at the bottom of the casting 34. The port 49 communicates with the outlet of the pump 46. A filter 47 is provided between the pump 46 and the port 49. The filter 47 functions to remove impurities such as ions and particles from the chemical solution 19. The inlet side of the pump 46 communicates with the drain 38 of the overflow tank 37. Therefore, the chemical solution 19 circulates through the casting 34, the overflow tank 37 and the filter 47 by the pump 46.

On the other hand, deionized water (DIW) in a water bath (not shown) circulates in an open path, while the chemical solution circulates in a closed loop for each wafer.

2 shows a deionized water tank 100. The deionized water tank 100 includes a wafer (W) housed therein, an inner tank 110 to which deionized water is supplied, and an outer tank 120 which receives and discharges deionized water overflowed from the inner tank 110. Two pipelines 130 pass under the wafer W accommodated in the inner tank 110. In each of the pipelines 130, a jet hole 135 is formed at a point facing approximately 45 degrees of the inner tank 110 to spray deionized water toward the wafer W.

Deionized water discharged through the outer tank 120 is again injected into the inner tank 110 through each pipeline 130 by the pump (P). Before the deionized water is introduced into the pipeline 130, the deionized water is filtered through the filter (F), and the substance contained therein is filtered, and thereafter, the deionized water is heated to a state above a predetermined temperature through the heater (H). Supplied into 110.

The wafer W is fixedly supported in the inner bath 110 such that its flat zone, that is, the cut portion, faces downward. At this time, the deionized water sprayed from the jet port 135 of each pipeline 130 is not smoothly supplied to the flat portion. This is a phenomenon caused by the ejection opening 135 is oriented toward the upper portion of the flat portion, and represents a problem that gas residues or natural oxide films after dry etching are not uniformly washed over the entire surface of the wafer (W). In addition, after the cleaning of the chemical solution, the degree of de-ionized water (DIW) reaching the flat portion is late compared to other portions, resulting in non-uniformity in terms of etching rate.

An object of the present invention is to solve the problems of the prior art, to provide a wafer cleaning apparatus that can eliminate the process defects caused by variations in the etching rate of the wafer.

In order to achieve the above object of the present invention, the present invention provides an inner tub for accommodating a wafer to be cleaned, an outer tub for accommodating the inner tub and an overflow of the washing water flowing therefrom, and the lower both sides of the wafer. A pair of first pipe lines provided to supply the washing water toward the wafer, a second pipe line provided below the flat portion of the wafer to supply the washing water in a direction facing the flat portion, and the second pipe line And a pair of guides for guiding the washing water supplied from the washing machine to the flat part, and a pump for supplying the washing water overflowed to the outer tank back to the first and second pipe lines. It provides a wafer cleaning apparatus.

According to a feature of the invention, each of the first pipe line is formed with two first ejection openings that are oriented in the wafer direction, and the second pipe line is formed with two second ejection openings in a direction facing the wafer; The washing water sprayed through the second jet port is changed in the flow direction along the guide and guided to the flat portion of the wafer. A filter may be further disposed between the pump and the first and second pipe lines to filter foreign substances contained in the washing water passing therethrough, and a heater heating the washing water to a predetermined temperature or more.

Unevenness of the washing water spray can be prevented, thereby reducing process defects due to the washing variation.

Hereinafter, an embodiment of the present invention will be described in more detail with reference to the accompanying FIG. 3.

3 shows a wafer cleaning apparatus 200 according to an embodiment of the present invention. In this detailed description, the wafer cleaning apparatus is described as being limited to a deionized water tank, but it is obvious that the technical idea of the cleaning apparatus may be applied to a chemical solution cleaning apparatus.

Referring to FIG. 3, the wafer cleaning apparatus 200 may include an inner tub 210 accommodating the wafer W to be cleaned and an outer tub accommodating the inner tub 210 and the washing water overflowing therefrom; 220). The wafer (W) to be cleaned refers to a wafer that needs to be cleaned after the etching process, and a wafer that has undergone chemical cleaning. In the inner tank 210, a pair of first pipe lines 230 are provided on both lower sides of the wafer W to supply DI water toward the wafer W. In practice, the first pipe line 230 extends in a direction perpendicular to the drawing, and is installed through a plurality of wafer cleaning apparatuses, that is, a plurality of inner tank lower parts. In the first pipe line 230, two first blow holes 235 are orientated in the wafer W direction.

A second pipe line 240 is additionally provided below the flat portion of the wafer W, that is, the flat portion of the wafer W. The second pipe line 240 supplies the washing water in a direction opposite to the flat portion. That is, two second jet holes 245 are formed in the second pipe line 240 in a direction facing the wafer W to spray the washing water therethrough. A pair of guides 250 are formed at the bottom of the inner tank 210 to guide the washing water supplied from the second pipe line 240 to the flat portion. The guide 250 is a substantially triangular shaped member, and changes the flow direction of the washing water injected through the second jet hole 245 to guide the flat portion of the wafer W.

On the other hand, a pump 260 for supplying the wash water overflowed to the outer tub 220 to the first and second pipe lines 230 and 240 is provided. Preferably, between the pump 260 and the first and second pipe lines 230 and 240, a filter 270 for filtering foreign matter contained in the washing water passing therethrough and a heater for heating the washing water to a predetermined temperature or more ( 280 is disposed.

Hereinafter, the operation of the wafer cleaning apparatus 200 according to an embodiment will be described.

In the inner tank 210, before the wafer W is transferred, the washing water is supplied and locked when the wafer W is seated. After the wafer W is seated, the pump 260 is operated to spray the washing water into the inner tank 210 through the first and second pipe lines 230 and 240. From the first jet port 235 of the first pipe line 230, washing water is injected at an angle of about 30 to 60 degrees over the entire surface of the wafer W, and the second jet port 245 of the second pipeline 240 is sprayed. From the washing water is sprayed downward. The washing water sprayed through the second jet port 245 takes the pair of guides 250 installed on the bottom of the inner tank 210, and the flow direction thereof is changed upward again. The redirected washing water intensively washes the flat region of the wafer (W). On the other hand, during the washing process, the washing water overflowed from the inner tank 210 is introduced into the outer tank 220, and again flows into each pipeline through the pump 260, the filter 270 and the heater 280, the inner tank 210 ) Is sprayed into.

As described above, additional washing water may be sprayed onto the flat portion of the wafer so that the washing water is uniformly sprayed over the entire surface of the wafer. Therefore, it is possible to prevent the process failure due to the deviation of the etching rate of the specific site.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (3)

An inner tub containing the wafer to be cleaned; An outer tub for accommodating the inner tank and into which the washing water overflowed therefrom is introduced; A pair of first pipe lines provided on opposite sides of the wafer to supply the washing water toward the wafer; A second pipe line provided under the flat zone of the wafer to supply the washing water in a direction opposite the flat zone; And And a pair of guides for guiding the washing water supplied from the second pipe line to the flat portion. The method of claim 1, wherein each of the first pipe line is formed with two first ejection openings orientated in the wafer direction, the second pipe line is formed with two second ejection openings in a direction facing the wafer, The washing water sprayed through the second jet port is a wafer cleaning apparatus, characterized in that the flow direction is changed along the guide is guided to the flat portion of the wafer. The pump of claim 1, further comprising: a pump for supplying the overflowed wash water back to the first and second pipelines, the wash water disposed between and passing through the pump and the first and second pipe lines. Wafer cleaning apparatus further comprises a filter for filtering the foreign matter and a heater for heating the washing water to a predetermined temperature or more.

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