JP2005332904A - Semiconductor substrate cleaning equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide semiconductor substrate cleaning equipment which cleans a semiconductor substrate so that contaminant which is exfoliated by cleaning does not stick again and can exhaust contaminant etc. which remains into cleaning liquid of a treatment tank upper part. <P>SOLUTION: The cleaning liquid which is filtered with a filter 4 and poured from a bottom surface of the treatment tank 1 is divided with a straightening vane, and difference is generated in flow velocity of the cleaning liquid at the surface and the back of the semiconductor substrate, so that re-sticking of exfoliated contaminant can be prevented. Furthermore, the cleaning liquid poured from both the side surface and the bottom surface of the treatment tank 1 is exhausted from an outlet 6 prepared on the side surface of the treatment tank 1, so that not only suspended substance of the cleaning liquid surface level but also the contaminant in the cleaning liquid which remains in the treatment tank upper part can be exhausted to an overflow tank 2 without re-sticking on the semiconductor substrate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor substrate cleaning apparatus for cleaning a semiconductor substrate immersed while circulating a cleaning liquid.

  In a semiconductor substrate cleaning apparatus comprising a processing tank and an overflow tank, the cleaning liquid is injected from the lower part of the processing tank in which the semiconductor substrate is immersed, overflowed from the upper part of the processing tank, recovered in the overflow tank, and from the cleaning liquid recovered by the filtration device After removing the contaminants, the filtered cleaning solution is circulated again to the treatment tank to clean the semiconductor substrate.

  In a batch type semiconductor substrate cleaning apparatus that simultaneously cleans a plurality of semiconductor substrates, a wafer guide provided with a guide groove for holding the semiconductor substrate or a carrier is used. A plurality of semiconductor substrates are held using a guide groove in a wafer guide provided in the processing tank, or a carrier holding a semiconductor substrate using a guide groove is placed in the processing tank, and the entire semiconductor substrate is By circulating the cleaning liquid while immersed in the cleaning liquid, impurities such as foreign matters and contaminants attached to the surface of the semiconductor substrate are removed.

  For example, Document 1 discloses such a semiconductor substrate cleaning apparatus.

Japanese Patent Application Laid-Open No. 64-7622

  However, in a batch type semiconductor substrate cleaning apparatus that simultaneously cleans a plurality of semiconductor substrates, for example, foreign substances and contaminants peeled off from the semiconductor substrate due to the flow of the cleaning liquid cause transfer adhesion that adheres to adjacent semiconductor substrates. There was a thing.

  Further, according to the semiconductor substrate cleaning apparatus disclosed in Document 1, it is possible to remove suspended matters by blowing a gas onto the surface of the cleaning liquid, but foreign substances and contaminants staying in the cleaning liquid at the top of the processing tank 20 There was a problem that it could not be removed.

  Accordingly, an object of the present invention is to provide a semiconductor substrate cleaning apparatus in which contaminants peeled off from a semiconductor substrate are not reattached to an adjacent semiconductor substrate. Another object of the present invention is to discharge the suspended matter on the surface of the cleaning liquid and the contaminants remaining in the cleaning liquid at the top of the processing tank to the outside of the processing tank.

  In order to solve the above problems, the invention of claim 1 is a semiconductor substrate cleaning apparatus for cleaning a semiconductor substrate in a processing tank by circulating a cleaning liquid while filtering, wherein the semiconductor substrate is in the flow of the cleaning liquid. The flow of the cleaning liquid is divided into two flows having different flow velocities on the upstream side, one of which passes through the front side of the semiconductor substrate and the other has a rectifying plate that passes through the back side of the semiconductor. .

  Further, the invention of claim 2 is a semiconductor substrate cleaning apparatus that circulates the cleaning liquid while filtering it to clean the semiconductor substrate in the processing tank, and includes a holding unit that holds the semiconductor substrate in the processing tank. The holding means divides the flow of the cleaning liquid into two flows having different flow velocities on the upstream side of the semiconductor substrate in the flow of the cleaning liquid, one passing through the front side of the semiconductor substrate, and the other A rectifying plate that allows the back side of the semiconductor to pass therethrough is provided.

  The invention of claim 3 is the semiconductor substrate cleaning apparatus according to the invention of claim 1 or claim 2, wherein the processing tank is provided with a first injection port for injecting the cleaning liquid from the bottom surface, and from the upper part of the side surface. A second inlet for injecting the cleaning liquid; and an outlet for discharging the cleaning liquid from an upper portion of the side surface facing the side surface, and the cleaning liquid injected from the first and second inlets from the outlet. It is characterized by discharging.

  When cleaning the semiconductor substrate with the flow of cleaning liquid circulating while filtering, the cleaning liquid flow on the front surface of the semiconductor substrate is made faster than the flow of cleaning liquid on the back surface, so that contaminants peeled off from the back surface can reattach to the surface. Can be avoided.

<Structure of semiconductor substrate cleaning equipment>
FIG. 1 shows the configuration of a semiconductor substrate cleaning apparatus according to one embodiment of the present invention. The semiconductor substrate cleaning apparatus is a pump for circulating a cleaning liquid between a processing tank 1 filled with a cleaning liquid for immersing and cleaning a semiconductor substrate, and an overflow tank 2 for recovering the cleaning liquid overflowed from the processing tank. 3, a filter 4 for filtering the circulating cleaning liquid to remove foreign substances and contaminants contained in the cleaning liquid, and two valves 5A and 5B for controlling the flow of the cleaning liquid into the treatment tank 1, Consists of Although not shown, the semiconductor substrate cleaning apparatus may include a functional unit for adjusting the temperature of the cleaning liquid in addition to these components.

  The arrows shown in FIG. 1 indicate the flow of the cleaning liquid, and the arrows connected from the overflow tank 2 to the processing tank 1 via the pump 3, the filter 4, and the valves 5A and 5B are constituted by pipes or the like. An arrow from the processing tank 1 to the overflow tank 2 indicates how the cleaning liquid is discharged from the processing tank 1 to the overflow tank 2 due to overflow or the like.

  FIG. 2 is a perspective view of the processing tank 1 and the overflow tank 2 as viewed from above. As shown in FIG. 2, the treatment tank 1 is provided with a discharge port 6 in the upper part of the side of the treatment tank 1 in contact with the overflow tank 2 so that the cleaning liquid can be discharged from the side surface of the treatment tank 1 to the overflow tank 2. The discharge port 6 is provided on a surface facing the injection port (second injection port) of the cleaning liquid injected into the processing tank 1 through the valve 5B, and the cleaning liquid injected into the processing tank 1 through the valve 5B is It flows in the injected direction and is directly discharged to the overflow tank 2 through the discharge port 6.

  The processing tank 1 performs batch cleaning for cleaning a plurality of semiconductor substrates at the same time, and is compatible with both carrier type and carrierless type. When the carrier is not used, as shown in FIG. 3, the wafer guide 8 is installed in the processing tank, and cleaning is performed with the semiconductor substrate 7 held in the guide groove provided in the wafer guide 8. When the carrier is used, as shown in FIG. 4, the carrier 10 holding the semiconductor substrate 7 in the guide groove is placed in the processing tank for cleaning. The wafer guide 8 and the carrier 10 (holding means) are provided with rectifying plates 9 so as to be positioned below the semiconductor substrates 7 when the semiconductor substrates 7 are held. FIG. 5 is a cross-sectional view showing the positional relationship between the semiconductor substrate 7 and the current plate 9. Thus, the cross section of the rectifying plate 9 divides the flow of the cleaning liquid from the bottom of the rectifying plate 9 to the semiconductor substrate 7 on the rectifying plate 9 into two flows, an arc-shaped surface and a linear surface. The shape is like this.

<Operation of semiconductor substrate cleaning equipment>
Next, details of an actual operation when the semiconductor substrate 7 is cleaned in the semiconductor substrate cleaning apparatus having the above configuration will be described.

  First, the semiconductor substrate 7 held by using the guide groove in the wafer guide 8 as shown in FIG. 3 or the carrier 10 as shown in FIG. 4 is immersed in a cleaning liquid filling the processing tank 1.

  Next, with the valve 5B shown in FIG. 1 closed and the valve 5A opened, the pump 3 is operated to circulate the cleaning liquid. At this time, the cleaning liquid is injected from the inlet (first inlet) on the bottom surface of the processing tank 1. The cleaning liquid flows from the lower side to the upper side of the semiconductor substrate 7 installed in the processing tank 1 to wash away foreign matters and contaminants attached to the surface of the semiconductor substrate 7 and overflow from the upper surface of the processing tank 6. The overflowing cleaning liquid is collected in the overflow tank 2 and then returned to the processing tank 1 from the inlet on the bottom of the processing tank 1 through the filter 4 and the valve 5A by the operation of the pump 3. At this time, the cleaning liquid is filtered by the filter 4 to remove foreign matters and contaminants. Therefore, by continuing such circulation of the cleaning liquid, impurities attached to the semiconductor substrate 7 can be removed in the filter 4.

  The flow of the cleaning liquid injected from the inlet of the bottom surface of the processing tank 1 through the valve 5A is as shown by the arrows in FIG. 5 and the rectifying plate 9 is composed of an arcuate surface and a straight surface. Thus, the front surface and the back surface of the semiconductor substrate 7 are divided into two flows that respectively flow upward. At this time, as it is known that there is a difference in the air flow velocity between the upper surface side and the lower surface side of the blade cross section in a wind tunnel experiment in aerodynamics, the arcuate surface side and the straight surface side of the rectifying plate 9 As a result, a difference occurs in the flow rate of the cleaning liquid flowing along the respective surfaces. That is, the flow rate of the cleaning liquid is faster on the arcuate surface side than on the linear surface side.

  When foreign substances or contaminants attached to the back surface 7b of the semiconductor substrate shown in FIG. 5 are peeled off by the cleaning liquid that flows from the lower side to the upper side, the flow of the cleaning liquid in the vicinity of the front surface 7a of the adjacent semiconductor substrate Since it is faster than the flow of the cleaning liquid, the flow of the cleaning liquid obstructs the flow of the cleaning liquid, and the foreign matter and contaminants are transferred to the upper part of the processing tank 1 without overflowing and adhering to the semiconductor substrate 7a. It will be collected in the tank 2. Therefore, if the rectifying plate 9 is installed so that the flow velocity on the surface of the semiconductor substrate 7 is faster than the flow velocity on the back surface, transfer of foreign matters and contaminants from the adjacent semiconductor substrate back surface 7b to the semiconductor substrate surface 7a can be avoided. A clean surface of the semiconductor substrate 7 can be obtained.

  Note that the cross-sectional shape of the rectifying plate 9 shown in FIG. 5 is an example, and the present invention is not limited to this, and a mode in which a difference occurs between the flow velocities of the two flows of the cleaning liquid divided by the rectifying plate 9. If so, it may be formed of a wing shape or other shapes.

  3 and 4 show a mode in which the wafer guide 8 and the carrier 10 have the rectifying plate 9 as a part of the structure thereof, the present invention is not limited to this. For example, while using a conventional wafer guide 11 and carrier 12 having no current plate as shown in FIGS. 8 and 9, a current plate 9 assembled like a saw as shown in FIG. It may be installed and used. Alternatively, as shown in FIG. 7, the processing tank 1 has a rectifying plate 9 as a part of its structure, and a wafer guide 24 and a carrier 25 are installed on the upper part thereof. You may be the aspect to do.

  In this way, by using the rectifying plate 9 to cause a difference in the flow rate of the cleaning liquid between the front side and the back side of the semiconductor substrate 7, the semiconductor substrate 7b that has become a problem in the batch type semiconductor substrate cleaning apparatus. It is possible to avoid the phenomenon that foreign matter and contaminants peeled off from the substrate are transferred and adhered to the adjacent semiconductor substrate 7a.

  The semiconductor substrate 7 that has been cleaned is pulled up from the processing bath 1. At this time, in order to prevent foreign matters or contaminants that float on the cleaning liquid surface or stay in the cleaning liquid at the top of the processing tank 1 from adhering to the semiconductor substrate 7, these floating substances and stagnant substances are included in advance. The cleaning liquid at the top of the processing tank 1 is discharged to the overflow tank 2.

  As shown in FIG. 1, in addition to the state in which the valve 5A is opened, when the valve 5B is opened, the cleaning liquid injected from the inlet provided on the side surface of the processing tank 1 flows through the valve 5B in the injected direction. , Discharged from the discharge port 6. As a result, foreign matters, contaminants, etc. that float on the cleaning liquid level or stay in the upper part of the processing tank 1 can be discharged to the overflow tank 2. At this time, the flow of the cleaning liquid from the lower side to the upper side of the processing tank 1 is also generated by the cleaning liquid injected from the inlet of the bottom surface of the processing tank 1 through the valve 5A. Therefore, foreign matters, contaminants, etc. that float on the cleaning liquid surface or stay in the upper part of the processing tank 1 are pushed back toward the semiconductor substrate 7 installed below the processing tank 1 by the flow of the cleaning liquid injected through the valve 5B. It will not be. Therefore, it is possible to discharge the cleaning liquid in the upper part of the processing tank 1 to the overflow tank 2 while maintaining the cleanliness of the semiconductor substrate 7 after cleaning.

  Note that the shape and the number of the discharge ports 6 shown in FIG. 2 are merely examples, and the present invention is not limited to this, and other modes may be used as long as the cleaning liquid can be discharged. Further, the discharge port 6 may be in an openable / closable manner in addition to a state in which the discharge port 6 is always open during the cleaning of the semiconductor substrate 7. Specifically, for example, when the valve 5B is closed and only the valve 5A is opened to clean the semiconductor substrate 7, the discharge port 6 is closed and the cleaning liquid is overflowed and discharged only from the upper side of the processing tank 1, and the cleaning liquid Even when the valve 5B and the discharge port 6 are opened and the cleaning liquid is discharged from the discharge port 6 only when the purpose is to remove foreign matters or contaminants floating on the surface or staying in the upper part of the processing tank 1. I do not care.

  In this way, if the cleaning liquid is injected from the inlet provided on the upper side of the processing tank 1 and discharged from the outlet provided on the surface opposite to the inlet, the cleaning liquid is different from the conventional method of blowing gas onto the cleaning liquid surface. In addition to suspended matter on the liquid surface, foreign substances and contaminants that remain in the cleaning liquid at the top of the treatment tank 1 can be discharged. At this time, since the cleaning liquid is also injected from the injection port provided on the bottom surface of the processing tank 1, recontamination of the semiconductor substrate 7 can be avoided. Therefore, it becomes possible to pull up the semiconductor substrate 7 while maintaining the cleanliness after the cleaning from the processing tank 1 while avoiding recontamination due to impurities in the cleaning liquid at the top of the processing tank 1.

It is a figure which shows the structure of the semiconductor substrate cleaning apparatus which concerns on one embodiment of this invention. It is a figure which shows the discharge port provided in the processing tank of the semiconductor substrate cleaning apparatus which concerns on one embodiment of this invention. It is a figure explaining the structure of the wafer guide utilized with the semiconductor substrate cleaning apparatus which concerns on one embodiment of this invention. It is a figure explaining the structure of the carrier utilized with the semiconductor substrate cleaning apparatus which concerns on one embodiment of this invention. It is a figure explaining the effect of the baffle plate of the semiconductor substrate cleaning apparatus which concerns on one embodiment of this invention. It is a figure which shows the example of the baffle plate utilized with the semiconductor substrate cleaning apparatus which concerns on one embodiment of this invention. It is a figure which shows the baffle plate with which the semiconductor substrate cleaning apparatus which concerns on one embodiment of this invention was equipped. It is a figure which shows the wafer guide utilized with the conventional semiconductor substrate cleaning apparatus. It is a figure which shows the carrier utilized with the conventional semiconductor substrate cleaning apparatus.

Explanation of symbols

1 treatment tank, 2 overflow tank, 3 pump, 4 filter, 5A, 5B valve, 6 discharge port, 7 semiconductor substrate, 8 wafer guide, 9 current plate, 10 carrier.

Claims (3)

A semiconductor substrate cleaning apparatus for cleaning a semiconductor substrate in a processing tank by circulating a cleaning liquid while filtering,
On the upstream side of the semiconductor substrate in the flow of the cleaning liquid, the flow of the cleaning liquid is divided into two flows having different flow velocities, one passing through the front side of the semiconductor substrate and the other passing through the back side of the semiconductor. Baffle plate,
A semiconductor substrate cleaning apparatus comprising: A semiconductor substrate cleaning apparatus for cleaning a semiconductor substrate in a processing tank by circulating a cleaning liquid while filtering,
Holding means for holding the semiconductor substrate in the processing tank;
With
The holding means is
On the upstream side of the semiconductor substrate in the flow of the cleaning liquid, the flow of the cleaning liquid is divided into two flows having different flow velocities, one passing through the front side of the semiconductor substrate and the other passing through the back side of the semiconductor. Baffle plate,
A semiconductor substrate cleaning apparatus comprising: A semiconductor substrate cleaning apparatus according to claim 1 or 2, wherein
The treatment tank is
A first inlet for injecting the cleaning liquid from the bottom;
A second inlet for injecting the cleaning liquid from the upper side surface;
A discharge port for discharging the cleaning liquid from the upper part of the side surface facing the side surface;
With
A semiconductor substrate cleaning apparatus, wherein the cleaning liquid injected from the first and second injection ports is discharged from the discharge port.

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