JP2019082458A - Water quality evaluation device and water quality evaluation method - Google Patents

Abstract

To provide a water quality evaluation device and a water quality evaluation method which are able to accurately and with high detection probability detect all impurities present in superpure water for cleaning a semiconductor wafer.SOLUTION: According to the invention, the water quality evaluation device comprises: treatment means for specifically processing and manipulating a measured board; support means for supporting the measured board horizontally with a surface facing upward; dropping means for dropping evaluated water onto the surface of the specifically processed and manipulated measured board; and analysis means for analysing a watermark that is formed on the surface of the measured board after the measured board including the evaluated water dropped thereon is dried.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a water quality evaluation apparatus and a water quality evaluation method, and more particularly to a water quality evaluation apparatus and a water quality evaluation method of ultrapure water used for cleaning a semiconductor wafer.

  In the manufacturing process of LSI (large scale integrated circuit), ultrapure water is used for cleaning a semiconductor wafer. Since such ultrapure water is a substance that comes in contact with the semiconductor wafer at the end of the cleaning process, the concentration of impurities contained in the ultrapure water greatly affects the degree of cleaning of the semiconductor wafer surface. For this reason, with the increase in the degree of integration of LSI in recent years, the demand for reduction of impurities such as fine particles present in ultrapure water used in the manufacturing process of LSI is increasingly increasing. Various methods have been proposed to evaluate the amount of impurities in ultrapure water by measuring resistivity or the like.

  Impurities such as fine particles present in ultra pure water for cleaning as described above are roughly classified into impurities that may adhere to the surface of the semiconductor wafer and adversely affect its characteristics, and adhere to the surface of the semiconductor wafer However, there are trace amounts of impurities which may remain in the fine structure formed on the surface and adversely affect the characteristics of the device using the semiconductor wafer. In order to obtain a highly clean semiconductor wafer by cleaning, it is desirable to be able to accurately evaluate all these impurities.

  Therefore, according to Patent Document 1 and Patent Document 2, the measurement substrate is held in a closed container, ultrapure water to be evaluated is passed through the container and brought into contact with the measurement substrate, and then the measurement substrate is measured by the particle counter. The method of evaluating the number of microparticles | fine-particles adhering to the measurement board | substrate surface by doing is disclosed. By using the methods disclosed in Patent Document 1 and Patent Document 2, it is possible to accurately evaluate the impurities attached to the surface of the measurement substrate, and to evaluate a large volume of ultrapure water, which is an evaluation target. It is possible to increase the accuracy. However, this method can not evaluate impurities such as minute amounts of fine particles which are not attached to the surface of the measurement substrate but are incorporated into the finer structure of the surface.

  On the other hand, according to Patent Document 3, after a very small amount of ultrapure water to be evaluated is dropped on a measurement substrate (sapphire substrate) and dried, the water mark formed on the measurement substrate is a three-dimensional image. A method of performing analysis and evaluation is disclosed. By using the method disclosed in Patent Document 3, it is possible to evaluate a trace amount of impurities incorporated in the fine structure on the surface of the measurement substrate. However, in this method, the amount of ultrapure water that can be held on the measurement substrate depends on the size of the semiconductor wafer used, and only a very small amount of ultrapure water can be evaluated. May cause When using a measurement substrate having a hydrophilic surface, ultrapure water spreads very well on the surface of the measurement substrate and spreads thinly, so the ultrapure water to be evaluated should be kept in one place. As a result, the measurement range becomes wide and there is a possibility that the above trace amount of impurities can not be detected.

Patent No. 4449135 Patent No. 4507336 Patent No. 2772361

  As described above, the methods disclosed in Patent Document 1 and Patent Document 2 and the method disclosed in Patent Document 3 have different means for evaluating impurities, and therefore these methods can not be used in combination. Therefore, in the prior art, all impurities present in the ultrapure water for cleaning the semiconductor wafer, that is, impurities that may adhere to the surface of the semiconductor wafer and adversely affect the characteristics thereof, and adhere to the surface of the semiconductor wafer However, under the present circumstances, it is impossible to accurately evaluate all of the very small amounts of impurities that may remain in the fine structure formed on the surface and adversely affect the characteristics of the device using the semiconductor wafer.

  The present invention has been made based on the above situation, and is a water quality evaluation device capable of accurately evaluating all impurities present in ultrapure water for cleaning semiconductor wafers with a high detection probability. The purpose is to provide a water quality assessment method.

  In order to solve the above-described problems, according to the present invention, first, processing means for performing specific processing or operation on a substrate to be measured, and support means for horizontally supporting the substrate to be measured with its surface facing upward; Dropping means for dropping the water to be evaluated on the surface of the substrate to be measured which has been subjected to a specific processing or operation, and analysis to analyze the watermark formed on the surface of the substrate to be measured after drying the water to be measured And a water quality evaluation device provided with the following means (Invention 1).

  According to this invention (Invention 1), after the water to be evaluated is dropped on the surface of the substrate to be measured which has been subjected to the specific processing or operation, the substrate to be measured to which the water to be evaluated is dropped is dried. By analyzing the watermark formed on the surface of the measurement substrate, all impurities present in the water to be evaluated, that is, the impurities attached to the surface of the substrate to be measured, and not on the surface of the substrate to be measured are formed on the surface It is possible to evaluate all the trace impurities remaining in the fine structure.

  In the present invention, the “water mark” is formed by concentrating the substance existing in the aqueous solution on the substrate surface when the aqueous solution is dropped on the surface of the substrate such as a semiconductor wafer and dried. Dry, which is the so-called "water mark".

  In the said invention (invention 1), it is preferable that the said process means is a surrounding-wall part formation means which forms the surrounding wall part which divides the area | region closed on the surface of a to-be-measured board | substrate (invention 2).

  According to this invention (invention 2), the water to be evaluated is dropped onto the closed region partitioned by the peripheral wall portion formed on the surface of the substrate to be measured, as compared to the case where the flat measurement substrate is used. A large volume of water to be evaluated can be evaluated, and the evaluation accuracy can be enhanced. In addition, by adjusting the position where the peripheral wall portion is formed, the size of the closed area, that is, the range in which the water to be evaluated can be set can be set arbitrarily, so that measurement according to the volume and properties of the water to be evaluated is possible. It is.

  In the above invention (Invention 1), it is preferable that the processing means is a groove forming means for forming a groove which defines a closed region on the surface of the substrate to be measured (Invention 3).

  According to this invention (invention 3), the water to be evaluated is dropped onto the closed region partitioned by the groove portion formed on the surface of the substrate to be measured, as compared with the case where the flat measurement substrate is used. A large volume of water to be evaluated can be evaluated, and the accuracy of evaluation can be enhanced. In addition, by adjusting the position where the groove is formed, the size of the closed area, that is, the range for retaining the water to be evaluated can be arbitrarily set, so that the measurement according to the volume and nature of the water to be evaluated is possible. is there.

  In the above invention (Invention 1), preferably, the processing means is a suction means for curving in a concave shape by suctioning the substrate to be measured horizontally supported by the support means from the back surface (Invention 4).

  According to this invention (invention 4), since the water to be evaluated is dropped on the surface of the substrate to be measured which is concavely curved by suction, a large capacity can be obtained as compared with the case where a flat measurement substrate is used. The water to be evaluated can be the evaluation target, and the evaluation accuracy can be enhanced. In addition, due to the shape of the concavely curved substrate to be measured, the dropped water to be evaluated remains at one position on the surface of the substrate to be measured, and the water mark is formed in a narrow range on the surface of the substrate to be measured. Even in the case of using the measurement substrate having the surface of (1), the measurement range does not become wide, and the detection probability of the trace amount of impurities remaining in the fine structure formed on the surface of the measurement substrate can be enhanced.

  In the said invention (invention 4), it is preferable that the said suction means has a suction-lifter-like suction lifter or suction pump (invention 5).

  In the said invention (invention 1-5), it is preferable to further provide the observation means which observes the surface state of the to-be-measured board | substrate after said drying (invention 6).

  Usually, the observation of the surface condition of the semiconductor wafer after cleaning and drying is performed separately from the evaluation of the impurities present in the ultrapure water used for cleaning. According to this invention (Invention 6), when evaluating the impurities present in the ultrapure water, the state of the surface of the substrate to be measured after washing and drying can be observed together, which is efficient.

  In the said invention (invention 1-6), it is preferable that an evaluation environment is in a chamber (invention 7).

  According to this invention (Invention 7), by performing the water quality evaluation of the water to be evaluated in the chamber, it is possible to prevent the mixing of impurities such as fine particles from the outside air during the evaluation.

  In the said invention (invention 7), it is preferable that the inside of the said chamber is satisfy | filled with inert gas atmosphere (invention 8).

  According to this invention (Invention 8), oxygen contained in the atmosphere is prevented from being dissolved in the water to be evaluated by performing the water quality evaluation of the water to be evaluated after filling the chamber with the inert gas atmosphere in advance. be able to.

  Second, the present invention performs a specific processing or operation, a processing step of performing specific processing or operation on the substrate to be measured, a supporting step of horizontally supporting the substrate to be measured with its surface facing upward, and a specific processing or operation. Analysis of analyzing a drop formed on the surface of the substrate to be measured, a step of drying the substrate to be measured on which the water to be evaluated has been dropped, and a step of drying the substrate to be measured And a process for providing a water quality evaluation method (Invention 9).

  In the said invention (invention 9), it is preferable that the said process process is a surrounding wall part formation process which forms the surrounding wall part which divides the area | region closed on the surface of a to-be-measured board | substrate (invention 10).

  In the above invention (Invention 9), the processing step is preferably a groove forming step of forming a groove which defines a closed region on the surface of the substrate to be measured (Invention 11).

  In the above invention (Invention 9), preferably, the treatment step is a suction step in which the substrate to be measured horizontally supported by the support step is curved in a concave shape by suction from the back surface (Invention 12).

  In the said invention (invention 12), it is preferable to perform the said suction process using a suction disk shaped suction lifter or a suction pump (invention 13).

  In the said invention (invention 9-13), it is preferable to further provide the observation process which observes the surface state of the to-be-measured board | substrate after the said drying (invention 14).

  In the above invention (Inventions 9-14), it is preferable that the evaluation environment is in a chamber (Invention 15).

  In the above invention (Invention 15), the inside of the chamber is preferably filled with an inert gas atmosphere (Invention 16).

  According to the water quality evaluation device and the water quality evaluation method of the present invention, after the water to be evaluated is dropped onto the surface of the substrate to be measured subjected to the specific processing or operation, the substrate to be measured to which the water to be evaluated is dropped is dried By analyzing the water mark formed on the surface of the substrate to be measured after drying, all the impurities present in the water to be evaluated, that is, the impurities adhering to the surface of the substrate to be measured and not attached to the surface of the substrate to be measured All the trace impurities remaining in the microstructure formed on the surface can be evaluated.

It is a schematic cross section which shows the state which dripped the to-be-evaluated water on the surface of the to-be-measured board | substrate which performed the specific process or operation by the process means with which the water quality evaluation apparatus of this invention is equipped, Comprising: (a) is 1st embodiment (B) shows a second embodiment, (c) shows a third embodiment. It is a schematic diagram which shows the water quality-evaluation apparatus of this invention, Comprising: (a) is 1st embodiment, (b) has shown 3rd embodiment. It is explanatory drawing which shows the procedure of the water quality evaluation method using the water quality evaluation apparatus of 1st embodiment of this invention. It is explanatory drawing which shows the procedure of the water quality evaluation method using the water quality evaluation apparatus of 3rd embodiment of this invention.

  Hereinafter, embodiments of the water quality evaluation device and the water quality evaluation method of the present invention will be described with reference to the drawings as appropriate. The embodiments described below are for the purpose of facilitating the understanding of the present invention, and do not limit the present invention at all.

[Water quality evaluation device]
First Embodiment
FIG. 1A is closed by the peripheral wall portion w1 formed on the surface of the measurement substrate W by the peripheral wall portion forming means as the processing means included in the water quality evaluation apparatus 10 according to the first embodiment of the present invention It is typical sectional drawing which shows the state which dripped the to-be-evaluated water E in the area | region. The water quality evaluation apparatus 10 according to the first embodiment mainly includes a peripheral wall forming unit (not shown), a support unit 1, a dropping unit 3 and an analysis unit 4 as shown in FIG. The peripheral wall portion forming means forms a peripheral wall portion w1 that divides a closed region on the surface of the measurement target substrate W. The support means 1 supports the measurement substrate W horizontally with its surface facing upward. The dripping means 3 drips the to-be-evaluated water E in the closed area divided by the peripheral wall w1 formed on the surface of the substrate W to be measured. The analysis means 4 analyzes the water mark M formed on the surface of the substrate W after drying the substrate W onto which the water to be evaluated E is dropped. In the present embodiment, the supporting means 1 and the dropping means 3 are provided integrally with the chamber 5 so that the evaluation environment of the water to be evaluated E is in the chamber, and the peripheral wall forming means and the analyzing means 4 Is provided outside the chamber 5.

[Peripheral wall portion forming means]
The peripheral wall portion forming means forms the peripheral wall portion w1 that divides the closed region on the surface of the measurement target substrate W, and is provided outside the chamber 5 in the present embodiment. The formation of the peripheral wall w1 on the surface of the substrate to be measured W by the peripheral wall forming means can be performed manually or by an automatic device as required. The material of the peripheral wall w1 formed on the surface of the substrate to be measured W by the peripheral wall forming means is not particularly limited, but the surface is the one for holding the water to be evaluated E in one place. It is preferable that the water repellency is high, the adhesion to the substrate to be measured W is good, and elution does not occur, and examples thereof include Teflon (registered trademark) tape and the like. The height of the peripheral wall w1 is preferably about 50% of the thickness of the measurement substrate W.

  In the present embodiment, the peripheral wall forming means bonds the peripheral wall w1 separately formed to the measurement substrate W by adhesion or the like, but is not limited thereto. For example, the measurement substrate W And the peripheral wall portion w1 may be integrally molded.

  In the case where a flat measurement substrate is used by dropping the water to be evaluated E onto a closed region partitioned by the peripheral wall w1 formed on the surface of the measurement substrate W by providing the peripheral wall forming means. In comparison, a large volume of water to be evaluated E can be evaluated, and the evaluation accuracy can be enhanced. In addition, by adjusting the position where the peripheral wall w1 is formed, the size of the closed area, that is, the range in which the water to be evaluated E can be set can be arbitrarily set. Measurement is possible.

[Supporting means]
The support means 1 supports the measurement substrate W horizontally with its surface facing upward, and in this embodiment, is constituted by a support base 11 installed horizontally to the inner bottom surface of the chamber 5 ing. The support means 1 is not particularly limited as long as the substrate to be measured W can be horizontally supported with its surface facing upward. By providing the support means 1, the substrate W to be measured is horizontally supported with its surface facing upward, so the dropped water to be evaluated E is stably held without spilling.

[Dropping means]
The dripping means 3 drips the water to be evaluated E in a closed region partitioned by the peripheral wall w1 formed on the surface of the substrate to be measured W, and in the present embodiment, on the outer surface of the chamber 5 The control mechanism 31 is provided, and the nozzle 32 extends from the control mechanism 31 to the inside of the chamber 5. The water to be evaluated E is dropped to a closed region partitioned by the peripheral wall w1 formed on the surface of the substrate to be measured W through the nozzle 32. The amount of the to-be-evaluated water E to be dropped is controlled by the control mechanism 31 according to the size of the to-be-measured substrate W measured in advance. The dropping means 3 may further have an adjusting mechanism capable of adjusting the position of the tip of the nozzle 32. The dripping means 3 is not particularly limited as long as the water to be evaluated E can be dropped onto the surface of the substrate W to be measured, and for example, it is manually performed using a pipette filled with the water to be evaluated E It may be one. By providing the dripping means 3, it is possible to properly and appropriately drop the to-be-evaluated water E in a closed region partitioned by the peripheral wall w1 formed on the surface of the substrate to be measured W.

[Analytical means]
The analysis means 4 analyzes the water mark M formed on the surface of the substrate W after being naturally dried after dropping the water to be evaluated E, and is provided outside the chamber 5 in the present embodiment. However, it may be provided inside the chamber 5. Also, for example, the analysis unit 4 is disposed on a network (not shown), and analyzes the water mark M formed on the surface of the substrate to be measured W after drying in the chamber 5 through this network. It may be configured. The analysis means 4 is not particularly limited as long as impurities present in the water to be evaluated E can be evaluated by analyzing the water mark M formed on the surface of the substrate to be measured W after drying. A scanning electron microscope (SEM) or an energy dispersive X-ray analyzer (EDX) can be suitably used. By providing the analysis means 4, all the impurities present in the water to be evaluated E, that is, the impurities attached to the surface of the substrate W to be measured, and the microstructures not attached to the surface of the substrate W to be measured are formed on the surface It is possible to evaluate all the trace impurities remaining in the

[Chamber]
The chamber 5 is for preventing the mixing of impurities such as fine particles from the outside air, and has a frame 51 defining at least a working space. A support 11 is provided on the inner bottom surface of the frame 51. A control mechanism 31 is provided on the upper side of one of the outer surfaces of the frame 51, and the nozzle 32 extends from the control mechanism 31 into the chamber 5. The chamber 5 is not particularly limited as long as impurities such as fine particles can be prevented from being mixed in from the outside air, but a glove box capable of setting a pressure and introducing an inert gas can be suitably used. The inside of the chamber 5 may be filled in advance with an inert gas atmosphere. By performing the water quality evaluation of the water to be evaluated E in the chamber 5 filled with the inert gas atmosphere, it is possible to prevent oxygen contained in the atmosphere from being dissolved in the water to be evaluated E, thereby reducing the evaluation error. It becomes possible.

Second Embodiment
Next, a water quality evaluation device according to a second embodiment of the present invention will be described. The second embodiment is different from the above-described first embodiment only in the processing means. Therefore, only differences from the first embodiment will be described below, and the other descriptions will be omitted.

  FIG. 1B is a closed region partitioned by the groove w2 formed on the surface of the measurement substrate W by the groove forming means as the processing means included in the water quality evaluation apparatus according to the second embodiment of the present invention; It is a schematic cross section which shows the state which dripped the to-be-evaluated water E. FIG. The configuration of the water quality evaluation apparatus according to the second embodiment is different from the configuration of the water quality evaluation apparatus 10 according to the first embodiment shown in FIG. , Supporting means 1, dropping means 3, and analyzing means 4.

[Groove Forming Means]
The groove forming means forms the groove w2 for dividing the closed region on the surface of the measurement target substrate W, and is provided outside the chamber 5 in the present embodiment. The formation of the groove portion w2 on the surface of the measurement target substrate W by the groove portion forming means can be performed manually or by an automatic device as necessary. The depth of the groove w2 is preferably less than 50% of the thickness of the measurement substrate W.

  In the present embodiment, the groove forming means forms the groove w2 by scratching the surface of the measurement substrate W using a razor blade or the like, but is not limited to this. For example, the groove w2 is provided The measurement substrate W may be molded.

  Compared with the case where a flat measurement substrate is used, the evaluation water E is dropped onto a closed region partitioned by the groove w2 formed on the surface of the measurement substrate W by providing the groove formation means. A large volume of water to be evaluated E can be evaluated, and the evaluation accuracy can be enhanced. Further, by adjusting the position where the groove portion w2 is formed, the size of the closed region, that is, the range for retaining the water to be evaluated E can be arbitrarily set, so that the measurement according to the volume and properties of the water to be evaluated E Is possible.

Third Embodiment
Next, a water quality evaluation apparatus 10 'according to a third embodiment of the present invention will be described. The third embodiment is different from the first and second embodiments described above only in the supporting means and the processing means, so only the differences between the first embodiment and the second embodiment will be described below. , Other explanations are omitted. Further, in FIG. 2B, the same reference numerals are used for the same components as in FIG. 2A.

  FIG. 1 (c) shows that the water E to be evaluated is dropped on the surface of the substrate W to be measured concavely curved by the suction means 2 as the processing means included in the water quality evaluation system 10 'according to the third embodiment of the present invention. It is typical sectional drawing which shows the state which was carried out. The water quality evaluation apparatus 10 'according to the third embodiment mainly includes a support means 1', a suction means 2, a dropping means 3 and an analysis means 4 as shown in FIG. 2 (b). The support means 1 ′ horizontally supports the measurement substrate W with its surface facing upward. The suction unit 2 is configured to curve the concave-shaped measurement target substrate W supported horizontally by suctioning it from its back surface. The dripping means 3 drips the water to be evaluated E onto the surface of the substrate W to be measured that is curved in a concave shape. The analysis means 4 analyzes the water mark M formed on the surface of the substrate W after drying the substrate W onto which the water to be evaluated E is dropped. In the present embodiment, the support unit 1 ′, the suction unit 2, and the dropping unit 3 are provided integrally with the chamber 5 so that the evaluation environment of the water to be evaluated is in the chamber, and the analysis unit 4 is It is provided outside the chamber 5.

[Supporting means]
The support means 1 ′ horizontally supports the measurement substrate W with its surface facing upward, and in the present embodiment, the support base 11 ′ disposed horizontally with respect to the inner bottom surface of the chamber 5 The suction lifter 21 as suction means 2 which will be described later is fixed horizontally to the surface of the support 11 '. The support means 1 'is not particularly limited as long as it can horizontally support the substrate W with its surface facing upward. For example, the suction means 2 itself is a support means without the support 11'. It may be one that also functions as 1 ′. By providing the support means 1 ′, the substrate W to be measured is horizontally supported with its surface facing upward, so that the dropped water to be evaluated is stably held without spilling.

[Suction means]
The suction unit 2 is configured to curve the concave-shaped measurement target substrate W supported horizontally by suctioning it from its back surface. In the present embodiment, a suction lifter 21 having a suction disk shape is used as the suction unit 2. A suction lifter is a device with an adjustable suction function that is used by adsorbing to an object that is difficult to move or transport, such as a glass plate or a metal plate, and made of rubber that is removably attached to the back of the object The suction cup member is configured to be switchable between a suction state and a non-suction state. The suction means 2 is not particularly limited as long as it can suck the measurement substrate W supported horizontally from its back surface, and, for example, a mortar-shaped holding member for holding the measurement substrate W on its back surface And a pump for suctioning from the bottom of the holding member. The control of the degree of curvature of the substrate to be measured W may be performed visually, or may be performed, for example, by providing the suction means 2 with a control mechanism capable of controlling the degree of curvature of the substrate to be measured W. At this time, if the suction of the suction means 2 is too strong, the substrate to be measured W may be broken. Therefore, in the case of visual observation, it is preferable to perform the suction gradually.

  By providing the suction means 2, the substrate W to be measured can be curved in a concave shape, so a large volume of the water to be evaluated E can be evaluated as compared with the case where a flat measurement substrate is used. , Can improve the evaluation accuracy. Furthermore, due to the concavely curved shape of the substrate W to be measured, the dropped water E to be evaluated remains at one position on the surface of the substrate W, and the water mark M is in a narrow range on the surface of the substrate W Even if the measurement substrate W having a hydrophilic surface is used, the measurement range does not become a wide range because it is formed, and a trace amount of impurities remaining in the fine structure formed on the surface of the measurement substrate W Detection probability can be increased.

  The water quality evaluation apparatus according to the present invention may further include observation means for observing the surface state of the substrate to be measured W after drying. As an observation means, one by imaging analysis is preferable, and one by total reflection Fourier transform infrared spectroscopy (FTIR-ATR method) is particularly preferable. The FTIR-ATR method is an analysis method using an FTIR-ATR apparatus equipped with an imaging analysis function capable of obtaining chemical surface information of a substance, and the structure of the substance, in particular, the chemical structure of the chemical substance is enhanced. Since image analysis can be performed with accuracy, a large number of FTIR spectra can be acquired by one measurement, and the surface condition of the substrate W after drying can be observed from the measured spectra. The observation of the surface condition of the semiconductor wafer (substrate W to be measured) after cleaning and drying, which has been performed separately from the evaluation of the impurities present in the ultrapure water used for cleaning, by providing the observation means, Can be performed in conjunction with the evaluation of

  In addition, the water quality evaluation apparatus according to the present invention may further include a drying unit that dries the measurement target substrate W on which the evaluation target water E is dropped. The drying unit is not particularly limited as long as the substrate to be measured W on which the water to be evaluated E can be dropped can be dried. For example, an infrared lamp provided on the ceiling surface of the chamber 5, a heater provided inside the chamber 5, etc. It may be a spin dryer provided outside the chamber 5 or the like. When the drying means is an infrared lamp, it may have a reflection plate for effectively irradiating the light into the chamber 5. By providing the drying means, the watermark to be analyzed by the analysis means 4 can be formed on the surface of the measurement substrate W in a short time.

[Water quality evaluation method]
Next, a water quality evaluation method using the water quality evaluation apparatus according to the first to third embodiments described above will be described in detail with reference to FIGS. 3 and 4. In addition, in FIG.3 and FIG.4, about the component same as FIG. 2, a code | symbol is abbreviate | omitted suitably.

First Embodiment
The water quality evaluation method using the water quality evaluation apparatus 10 of the first embodiment is, as shown in FIG. 3, a treatment process (STP1), a support process (STP2), a dropping process (STP3), a drying process (STP4), an analysis process Mainly comprises (STP5).

[Processing step]
In the first embodiment, in the processing step, the peripheral wall w1 partitioning the area closed on the surface of the measurement substrate W is formed by the peripheral wall forming means (not shown) as processing means provided outside the chamber 5 (STP1).

[Supporting process]
In the supporting step, the substrate to be measured W is horizontally supported with its surface facing upward with respect to the support base 11 as the support means 1 in the chamber 5 (STP 2).

[Dropping process]
In the dropping step, the water to be evaluated E is dropped through the nozzle 32 in a closed region partitioned by the peripheral wall w1 formed on the surface of the measurement target substrate W (STP3). The amount of the to-be-evaluated water E to be dropped is controlled by the control mechanism 31 in accordance with the size of the to-be-measured substrate W measured in advance. In the dropping step, the end point may be a point in time when a predetermined water to be evaluated E is dropped in a closed region partitioned by the peripheral wall w1 formed on the surface of the measurement target substrate W.

[Drying process]
In the drying step, the substrate W to which the water to be evaluated E is dropped is dried by natural drying (STP 4). In the drying step, the end point may be the point when the water mark M is formed on the surface of the measurement target substrate W.

  In the present embodiment, the drying step is performed by natural drying, but may be performed using a drying unit. The drying unit is not particularly limited as long as the substrate to be measured W on which the water to be evaluated E can be dropped can be dried. For example, an infrared lamp provided on the ceiling surface of the chamber 5, a heater provided inside the chamber 5, etc. It may be a spin dryer provided outside the chamber 5 or the like. When the drying means is an infrared lamp, it may have a reflection plate for effectively irradiating the light into the chamber 5. By providing the drying means, the watermark M to be analyzed by the analysis means 4 can be formed on the surface of the measurement substrate W in a short time.

[Analytical process]
In the analysis step, the water mark M formed on the surface of the measurement target substrate W is analyzed by the analysis means 4 provided outside the chamber 5 (STP 5). More specifically, by analyzing the water mark M formed on the surface of the substrate W to be measured, the impurities present in the water to be evaluated E are evaluated. In the analysis step, all the impurities present in the water to be evaluated E, that is, the impurities attached to the surface of the substrate W to be measured, and the poles not attached to the surface of the substrate W to be measured but remaining in the fine structure formed on the surface All with trace impurities can be evaluated.

  In addition, the said water quality evaluation method may further be equipped with the observation process which observes the surface state of the to-be-measured board | substrate W after drying. In the observation step, the surface state of the substrate to be measured W after drying can be observed based on the spectrum measured by the FTIR-ATR apparatus as an observation means. The observation of the surface condition of the semiconductor wafer (substrate W to be measured) after cleaning and drying, which has been performed separately from the evaluation of the impurities present in the ultrapure water conventionally used for cleaning, by providing the observation step, Can be performed in conjunction with the evaluation of

  Also, the inside of the chamber 5 may be filled in advance with an inert gas atmosphere. By performing the water quality evaluation of the water to be evaluated E in the chamber 5 filled with the inert gas atmosphere, it is possible to prevent oxygen contained in the atmosphere from being dissolved in the water to be evaluated E, thereby reducing the evaluation error It is possible to

Second Embodiment
Next, a water quality evaluation method using the water quality evaluation device according to the second embodiment of the present invention will be described. The second embodiment is different from the above-described first embodiment only in the contents of the processing steps. Therefore, only differences from the first embodiment will be described below, and the other descriptions will be omitted.

[Processing step]
In the second embodiment, in the processing step, the groove w2 for dividing the closed region on the surface of the measurement substrate W is formed by the groove forming means (not shown) as the processing means provided outside the chamber 5 (STP1).

Third Embodiment
Next, a water quality evaluation method using the water quality evaluation device 10 'according to the third embodiment of the present invention will be described. Note that the third embodiment is different from the first and second embodiments described above in the order and contents of the supporting process and the processing process, so only the differences from the first embodiment will be described below. Other explanations are omitted.

  The water quality evaluation method using the water quality evaluation apparatus 10 'according to the third embodiment is, as shown in FIG. 4, a support process (STP1'), a treatment process (STP2 '), a dropping process (STP3), a drying process (STP4) And analysis step (STP5) mainly.

[Supporting process]
In the supporting step, the substrate to be measured W is horizontally supported with the surface thereof facing upward with respect to the suction cup member of the suction lifter 21 placed on the support 11 'in the chamber 5 (STP1'). At this time, the suction cup member of the suction lifter 21 is in the non-sucking state.

[Processing step]
In the third embodiment, in the processing step, the suction lifter 21 used as the suction means 2 as the processing means is switched to the suction state, and the substrate to be measured W is suctioned from the back surface thereof, thereby predetermined the substrate to be measured W It is made to curve concavely by the degree of curvature (STP2 '). The control of the degree of curvature of the substrate to be measured W may be performed visually, or may be performed, for example, by providing the suction means 2 with a control mechanism capable of controlling the degree of curvature of the substrate to be measured W. It is preferable that the treatment process, that is, the suction of the measurement substrate W by the suction lifter 21 be continued until the end point of the evaluation test.

  As described above, according to the water quality evaluation device and the water quality evaluation method of the present invention, the water to be evaluated is applied to the surface of the substrate to be measured which has undergone specific processing or operation such as formation of a peripheral wall, formation of a groove or suction. After dropping, the substrate to be measured to which the water to be evaluated has been dropped is dried, and the water mark formed on the surface of the substrate to be measured after drying is analyzed to determine all the impurities present in the water to be evaluated, that is, the substrate to be measured. It is possible to evaluate all of the impurities adhering to the surface of the substrate and the trace impurities not adhering to the surface of the substrate to be measured but remaining in the fine structure formed on the surface. When the specific processing or operation is the formation of a peripheral wall or the formation of a groove, the water to be evaluated is dropped onto a closed region partitioned by the peripheral wall or groove formed on the surface of the measurement substrate, As compared with the case of using a flat measurement substrate, a large volume of water to be evaluated can be evaluated, and the evaluation accuracy can be enhanced. When the specific processing or operation is suction, the water to be evaluated is dropped on the surface of the substrate to be measured that is concavely curved by suction, so compared to the case where a flat measurement substrate is used. A large volume of water to be evaluated can be evaluated, and the evaluation accuracy can be enhanced.

  As mentioned above, although this invention was demonstrated with reference to drawings, this invention is not limited to the said embodiment, A various change implementation is possible. In the present invention, the specific processing or operation is performed before dropping the water to be measured onto the substrate to be measured, but for example, the substrate to be measured is covered by a drop of the water to be evaluated dropped onto the test substrate After the substrate to be measured is dried in the allowed state, the water to be evaluated may be evaluated by analyzing a watermark formed on the surface.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.

  The evaluation test of the water to be evaluated was conducted as follows using the water quality evaluation device 10 shown in FIG. 2 (a).

Example 1: Watermark Analysis
(1) Number of Fine Particles Confirmed In the method disclosed in Patent Document 1 and Patent Document 2 (hereinafter referred to as Comparative Example 1), 0.2 μm remaining after passing 60 mm ³ of ultrapure water through the measurement substrate The number of particles above is measured with a particle counter. On the other hand, in Example 1, after 10 μL of ultrapure water is dropped on the measurement substrate and dried, the number of remaining particles of 10 nm or more is scanned by analyzing the watermark formed on the surface of the measurement substrate. It confirmed by the electron microscope (SEM). In addition, it was found that carbon-based particles, silica-based particles, and metal-based particles were mixed by measuring the particles by energy dispersive X-ray analysis (EDX).
(2) Volume of Ultrapure Water that can be Evaluated In the method disclosed in Patent Document 3 (hereinafter referred to as Comparative Example 2), 1 mL of ultrapure water is dropped on a measurement substrate (sapphire substrate). On the other hand, in Example 1, since the peripheral wall which divides the closed region is formed on the surface of the measurement substrate, a large volume of ultrapure water can be retained as compared to the case where a flat measurement substrate is used. In the case of a 6 inch measuring substrate, it was possible to drop ultrapure water to a maximum of 30 mL.
(3) Analysis range Although the range which performed three-dimensional image analysis is not specified in patent document 3 (comparative example 2), since the ultrapure water dropped is 1 mL, it is necessary to measure at least about 1 cm ² It is thought that there is. On the other hand, in Example 1, the size of the closed area, that is, the range for retaining the water to be evaluated can be arbitrarily set by adjusting the position where the peripheral wall portion is formed. Measurement is possible.

Table 1 shows the comparison results of Example 1, Comparative Example 1 and Comparative Example 2 for the above (1) to (3).

Example 2 Observation of Surface State of Substrate
The surface condition of the substrate to be measured after washing and drying was observed according to the following test procedure.
(1) As pretreatment, the Si wafer was washed with 0.5 wt% DHF for 2 minutes and then washed with ultrapure water for 2 minutes.
(2) A peripheral wall was formed on the surface of the pre-treated Si wafer using a Teflon (registered trademark) tape, and a closed region for dropping ultrapure water to be evaluated was produced.
(3) After the Si wafer is horizontally supported with its surface facing upward on the support of the water quality evaluation apparatus 10, it is used as water to be evaluated in a closed region partitioned by the peripheral wall formed on the surface of the Si wafer. 1 mL-20 mL of the ultrapure water of the above was added dropwise, and allowed to stand for 10 minutes-180 minutes.
(4) The Si wafer to which the ultrapure water was dropped was dried by natural drying.
(5) The spectrum of the outermost surface of the Si wafer after drying was measured using the FTIR-ATR apparatus.

  According to the above test procedure, ultrapure water (hereinafter referred to as ultrapure water 1) and ultrapure water (hereinafter referred to as ultrapure water 2) to which about 0.1 ppt of an organic substance that roughens the surface of the Si wafer are added. Comparison of the Si wafer surface after cleaning and drying using the results showed that the Si wafer onto which the ultra pure water 2 was dropped compared to the Si wafer onto which the ultra pure water 1 was dropped had the outermost surface in the measured spectrum. A clear change was observed in the region showing hydrogen termination, and it was confirmed that the surface of the Si wafer was rough or degraded.

  As described above, according to the water quality evaluation apparatus and the water quality evaluation method of the present invention, it is possible to accurately evaluate all the impurities present in the ultrapure water for cleaning semiconductor wafers with a high detection probability.

  INDUSTRIAL APPLICABILITY The present invention is useful as an apparatus and method for evaluating water quality of ultrapure water used for cleaning semiconductor wafers in a manufacturing process of LSI (large scale integrated circuit).

DESCRIPTION OF SYMBOLS 10, 10 'Water quality evaluation apparatus 1, 1' Support means 11, 11 'Support stand 2 Suction means 21 Suction lifter 3 Dropping means 31 Control mechanism 32 Nozzle 4 Analysis means 5 Chamber 51 Frame W W to-be-measured board w1 Peripheral wall part w2 Groove part E Water to be evaluated M Watermark

Claims (16)

Processing means for performing specific processing or operation on the substrate to be measured;
Supporting means for horizontally supporting the substrate to be measured with its surface facing upward;
Dropping means for dropping water to be evaluated onto the surface of the substrate to be measured which has been subjected to specific processing or operation;
A water quality evaluation apparatus comprising: an analysis unit that dries a substrate to be measured to which water to be evaluated is dropped and then analyzes a watermark formed on the surface of the substrate.   The water quality evaluation apparatus according to claim 1, wherein the processing means is a peripheral wall forming means that forms a peripheral wall that divides a closed region on the surface of the measurement substrate.   The water quality evaluation apparatus according to claim 1, wherein the processing means is groove forming means for forming a groove which divides a closed region on the surface of the measurement substrate.   The water quality evaluation apparatus according to claim 1, wherein the processing means is suction means for curving in a concave shape by suctioning the substrate to be measured horizontally supported by the support means from its back surface.   The water quality evaluation device according to claim 4, wherein the suction means comprises a suction lifter or suction pump in the form of a suction cup.   The water quality evaluation device according to any one of claims 1 to 5, further comprising observation means for observing the surface state of the substrate to be measured after drying.   The water quality evaluation device according to any one of claims 1 to 6, wherein the evaluation environment is in a chamber.   The water quality evaluation device according to claim 7, wherein the inside of the chamber is filled with an inert gas atmosphere. A processing step of performing specific processing or operation on the substrate to be measured;
A supporting step of supporting the substrate to be measured horizontally with its surface facing upward;
A dropping step of dropping water to be evaluated onto the surface of the substrate to be measured which has been subjected to a specific processing or operation;
A drying step of drying the substrate to be measured to which the water to be evaluated has been dropped;
And an analysis step of analyzing a watermark formed on the surface of the substrate to be measured after drying.   The water quality evaluation method according to claim 9, wherein the treatment step is a peripheral wall forming step of forming a peripheral wall that divides a closed region on the surface of the measurement substrate.   The water quality evaluation method according to claim 9, wherein the treatment step is a groove forming step of forming a groove which divides a closed region on the surface of the measurement substrate.   10. The water quality evaluation method according to claim 9, wherein the treatment step is a suction step of curving in a concave shape by suctioning the substrate to be measured horizontally supported by the support step from the back surface thereof.   The water quality evaluation method according to claim 12, wherein the suction process is performed using a suction-type suction lifter or a suction pump.   The water quality evaluation method according to any one of claims 9 to 13, further comprising an observation step of observing a surface state of the substrate to be measured after drying.   The water quality evaluation method according to any one of claims 9 to 14, wherein the evaluation environment is in a chamber.   The water quality evaluation method according to claim 15, wherein the inside of the chamber is filled with an inert gas atmosphere.

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