JPH10270393A - Method and device for cleaning wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cleaning effect for reduced foreign subjects depositing on a surface, by supplying water only without abrasives to a water surface, and polishing with the cleaning water contacting to a polishing surface. SOLUTION: A wafer substrate W delivered to a wafer substrate delivery vessel 13 is lifted up while sucked and held from upper surface side with a water polishing/cleaning top ring 14. Here, its surface is always supplied with cleaning water under shower, and while the wafer substrate W is sucked/held with the top ring 14, the entire surface of wafer substrate W always contacts to the cleaning water. Thus, the wafer substrate W is transferred to a water polishing/cleaning stool 15. While supplying cleaning water, the top ring 14 falls while sucking the wafer substrate W from upper surface side, to press the lower surface of wafer substrate W onto a abrasive fabric. Since the abrasive fabric is rotated together with the stool 15, the lower surface of wafer substrate W is mechanically polished/cleaned due to rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cleaning and polishing a wafer by removing foreign substances on the surface of a semiconductor wafer and cleaning the surface of the semiconductor wafer. The present invention relates to a method and an apparatus for cleaning and polishing a wafer.

[0002]

2. Description of the Related Art Generally, a wafer substrate obtained by slicing a silicon single crystal ingot to a certain thickness with a wire saw or an inner peripheral blade or the like has fine irregularities (that is, fine irregularities on its surface).
(Fine roughness, micro-roughness) or uneven thickness of individual wafer substrates. for that reason,
Perform lapping, flatten such fine irregularities,
The depth of the processing strain is made uniform, and the thickness of the wafer substrate is evenly adjusted.

[0003] Further, the wafer substrate after lapping includes:
Since there is a processing strain layer generated by the processing, and fine metal, polishing powder, particles such as silicon chips adhere to the processing strain layer, etching is performed by a chemical corrosion method using a strong acid or hydrofluoric acid. (Chemical etching) to remove the processing strain layer and the particles.

[0004] After etching, the wafer substrate is subjected to alkali neutralization to remove the acid adhering to the surface, thoroughly washed with water, dried, and mirror-polished on one side. After polishing, the wafer substrate is immersed in a cleaning bath and washed with running water (pre-cleaning), and then the surface particles and metal are further removed in the final cleaning process, which has high gloss with chemical luster and no processing distortion. Is obtained.

In general, the cleanliness of the wafer substrate surface directly affects the characteristics of the semiconductor device. If the cleanliness is reduced, it may cause a failure in forming a device pattern or adversely affect the electrical characteristics of the semiconductor device. .

[0006] The decrease in the cleanliness of the wafer substrate surface is caused not only by fine irregularities (ie, fine roughness and micro roughness) on the wafer substrate surface, but also by particles (fine particles) adhering to the wafer substrate surface in each wafer processing step. , Metal impurities, and foreign substances such as organic substances.

Therefore, conventionally, the micro-roughness is improved in each of the above-mentioned steps, ie, mechanical polishing (lapping), chemical etching, and mirror polishing (polishing), and further, polishing is performed in a cleaning tank supplied with a large amount of cleaning liquid. Foreign substances adhering to the surface of the wafer substrate are removed by pre-cleaning in which the wafer substrate is immersed later and final cleaning in which the wafer substrate after pre-cleaning is chemically cleaned.

[0008]

However, the conventional method of cleaning a wafer substrate has the following problems. In order to completely remove organic substances such as wax applied on the back side of the wafer substrate during polishing and abrasives remaining on the surface, cleaning must be performed for a long time in pre-cleaning,
take time.

In chemical etching and pre-cleaning, a large amount of an acid-based chemical such as hydrochloric acid, hydrofluoric acid, or nitric acid, or an alkali-based chemical such as sodium hydroxide or ammonium hydroxide is used as a cleaning liquid. Thus, the surface of the wafer substrate is cleaned by a chemical reaction. Since the reaction temperature at this time is high and the chemical solution must be maintained at a high temperature,
Huge power is required and costly.

In addition, a large amount of chemical liquid comes out as a waste liquid, and this chemical liquid needs to be treated and then discarded because it causes environmental pollution. Therefore, a separate step for waste liquid treatment is only required. In addition, there is a problem that the cost for that is also high. This is particularly serious because the larger the diameter of the wafer is, the larger the amount of the required chemical liquid is.

Further, the chemical solution attached to the wafer substrate after the chemical etching and the pre-cleaning is removed by neutralizing and thoroughly cleaning with water. Is corroded and haze occurs.

In the pre-cleaning, cleaning is performed by a method of supplying a cleaning liquid in a state where a wafer substrate is immersed in a cleaning tank and a method relying on a water flow of the cleaning liquid and a method relying on an operation by the chemical property of the cleaning liquid. However, it is not possible to forcibly remove foreign matter by using the above-mentioned machine, and it is difficult to reduce very small particles.

Further, foreign matter such as particles removed from the wafer substrate easily accumulates in the cleaning tank, and the foreign matter once detached from the surface of the wafer substrate adheres again due to convection in the cleaning tank, or is deposited in the cleaning tank. There is also a problem that it is difficult to completely remove the foreign matter on the wafer substrate surface because a phenomenon such as the remaining foreign matter sticking to the surface occurs. As described above, if the final cleaning is performed in a state where foreign matter is attached to the surface of the wafer substrate, the cleaning efficiency is reduced, and there is a problem that a highly purified wafer substrate cannot be finally obtained.

In the pre-cleaning, since a large amount of cleaning liquid is used, there is a problem that the apparatus becomes large-scale and the manufacturing cost increases. In particular, the problem becomes more remarkable as the diameter of the wafer to be manufactured becomes larger.

In order to avoid these problems, a double-side polishing method for simultaneously polishing both surfaces of the wafer substrate in mirror polishing or the like is employed, so that organic substances such as wax used for fixing the wafer substrate are not adhered. To eliminate the need for chemical etching and pre-cleaning.

However, if pre-cleaning is not performed, foreign substances such as particles, organic substances, and metal impurities adhering to the wafer substrate at the time of finishing the mirror polishing cannot be reduced as a pretreatment for final cleaning. For this reason, the final cleaning must be performed while the foreign matter is adhered to the wafer substrate, resulting in a decrease in the cleaning efficiency in the final cleaning, and there is a problem that a highly purified wafer substrate cannot be manufactured.

In view of the above, the present invention provides a wafer cleaning method and apparatus which can provide a highly-clean wafer substrate with improved cleaning effect as compared with the conventional one, that is, with less foreign matter adhering to the surface than the conventional one. Its main purpose is to:

It is another object of the present invention to provide a method and apparatus for cleaning and polishing a wafer in which the micro-roughness of the wafer substrate surface is improved.

Further, another object of the present invention is to provide a wafer cleaning method and a wafer cleaning method in which a surface of a wafer substrate is not corroded by an acid or an alkali used during a process or the like and a large amount of a strong acid or a strong alkali is not generated as a waste liquid. It is to provide.

It is another object of the present invention to provide a wafer cleaning method and apparatus which does not require pre-cleaning in wafer cleaning, has high cleaning efficiency with a small amount of cleaning liquid, and can easily perform post-processing such as waste liquid processing.

It is another object of the present invention to provide a method and apparatus for cleaning a wafer, which is smaller than the conventional apparatus as a whole and can reduce the manufacturing cost of a wafer substrate.

[0022]

In order to achieve the above object, the invention according to claim 1 is directed to cleaning the surface of a semiconductor wafer for the purpose of removing foreign substances and the like on the surface of the semiconductor wafer and improving the fine roughness. A method of supplying only cleaning water to the surface of the semiconductor wafer without using an abrasive, and having a water polishing cleaning step of polishing in a state where the cleaning water is in contact with a polishing surface. .

The present invention provides a wafer cleaning method capable of highly cleaning a semiconductor wafer substrate by a water polishing / cleaning step (first polishing step) in which a polished surface of a semiconductor wafer is polished in contact with cleaning water. To provide. still,
The polishing here is, for example, a mechanical method such as a buff polishing process on the surface of a semiconductor wafer using a platen or the like.

The semiconductor wafer described in the present invention means not only a wafer substrate cut out from a semiconductor ingot, but also a wafer substrate after rough polishing in a multi-step mirror polishing process, and other processes such as a device CMP process and an SOI process. It includes all wafer substrates whose surfaces require polishing or cleaning, such as patterned wafer substrates and oxide film-coated wafer substrates that have undergone a process.

For example, after lapping the surface of a wafer substrate cut out of a semiconductor single crystal (ingot), a mirror polishing step (second polishing step) for polishing to a mirror surface.
Wherein the mirror polishing step (second polishing step) comprises a two-step buff polishing step of a rough mirror polishing step and a precision finish polishing step. After that, by using different polishing means different from those used in the rough mirror polishing step and the fine finish polishing step, only the cleaning water is supplied to the surface of the wafer substrate which has been subjected to the rough mirror polishing without using an abrasive. In addition, the present invention also includes a method having a water polishing / cleaning step (first polishing step) for polishing in a state where the cleaning water is in contact with the polishing surface.

As described above, the water polishing and cleaning step of the present invention comprises:
It removes residual abrasives such as chemicals and abrasives used in the previous step, particles such as particles, organic substances and metal impurities adhered to the surface during the processing in the previous step or during the transfer of the wafer substrate.

Here, "polishing the polishing surface in contact with the cleaning water" means that only the cleaning water containing no abrasive is interposed between the surface of the wafer substrate to be polished and the polishing means. This refers to polishing the surface of the substrate, and a dedicated polishing method using no abrasive is used.

For example, this can be achieved by polishing the wafer substrate while constantly spraying only the cleaning water on the wafer substrate. In the case where only the cleaning water is supplied by the same polishing means after using the abrasive. Excluded. In other words, in the water polishing / cleaning step of the present invention, the wafer substrate surface can be buff-polished with only water by the polishing means, and at the same time, can be cleaned with cleaning water.

In the water polishing step of the present invention, water containing no abrasive is used as a fluid supplied for cleaning. This water is chemically purified, such as ultrapure water containing almost no impurities, or functional water that has been subjected to a certain treatment such as adding ultrasonic waves or adding ozone to the ultrapure water. Use a strong one.

Next, a second aspect of the present invention is to provide a method for removing a foreign substance or the like from a mirror-polished surface of a wafer substrate after lapping the surface of the wafer substrate cut from the semiconductor single crystal (ingot). A method of cleaning the surface of a wafer substrate for the purpose of improving roughness, wherein a (buffer) polishing means different from the above-mentioned mirror-polishing is used without using an abrasive on the mirror-polished surface of the wafer substrate. A water polishing and cleaning step of supplying only the cleaning water to the polishing surface and polishing in a state where the cleaning water is in contact with the polishing surface.

That is, according to the present invention, cleaning of the surface of a wafer substrate which has been cut from a semiconductor single crystal (ingot) and has been mirror-polished is performed separately from polishing means in a mirror polishing step (second polishing step). A water polishing cleaning step (first polishing step) in which the polishing surface of the wafer substrate is polished while being brought into contact with cleaning water by different polishing means, so that the wafer substrate is more highly purified than a conventional cleaning method by a pre-cleaning step. It is intended to provide a wafer cleaning method capable of performing the above.

The water polishing / cleaning step of the present invention is a step performed after reducing the roughness of the wafer substrate surface, that is, micro-roughness such as ripple and haze, by a lapping step and a mirror polishing step. It is intended to remove foreign substances such as residual abrasives, particles adhered to the surface during the processing of the previous process or transfer of the wafer substrate, organic substances or metal impurities, but further increase the micro roughness. There is also a reduction effect.

In the present invention, the condition of "polishing the polishing surface in contact with the cleaning water" is such that only the cleaning water containing no abrasive is interposed between the surface of the wafer substrate to be polished and the polishing means. This refers to polishing the surface of a wafer substrate. For example,
This can be achieved by polishing the wafer substrate while continuously spraying only the cleaning water onto the wafer substrate.

In other words, in the water polishing / cleaning step of the present invention, the surface of the wafer substrate can be polished by the polishing means and at the same time can be cleaned with the cleaning water. Unlike the method in which only the water is used to wash off with the polishing means, the same polishing means does not use any abrasive.

The polishing means is means (or apparatus) different from the polishing in the lapping step and the mirror polishing step.
The configuration is not particularly limited as long as the surface of the wafer substrate is polished. However, in order to prevent the foreign matter from the slurry or the like from adhering to the surface of the wafer substrate and thereby reducing the cleaning effect, the polishing means mechanically polishes the wafer substrate surface, not chemical polishing. Preferably, there is. For example, as a polishing means, a wafer substrate surface may be polished by a mechanical method such as buff polishing using a platen or the like or wiping.

In the water polishing and cleaning step, which is the first polishing step of the present invention, polishing is performed by supplying only cleaning water without using any abrasive in the polishing process. As a result, there is no possibility that the polishing material adheres (or remains) to the wafer surface and the wafer surface is contaminated.

Therefore, it is possible to forcibly remove foreign matter from the wafer substrate surface by polishing the wafer substrate surface with a polishing means and rinsing with a cleaning water. For example, small particles and the like cannot be removed by the conventional wafer substrate cleaning method. Foreign matter can be removed. At the same time, ultra-precision polishing is possible, and micro-roughness can be further improved.

Further, the foreign matter once removed from the wafer substrate is forcibly removed by the polishing means and the cleaning water, and does not accumulate on the wafer substrate surface, so that the foreign matter does not adhere again to the wafer substrate surface. .

As described above, the water polishing / cleaning step of the present invention makes it possible to more effectively remove foreign substances such as residual abrasives, particles, organic substances or metal impurities as compared with the conventional pre-cleaning. At the same time, the micro roughness can be improved.

Further, in the present invention, since the surface of the wafer substrate is cleaned using the cleaning water, the cleaning is performed using a chemical solution as in the related art, and compared with a process that requires treatment of a waste liquid such as acid or alkali. This also facilitates post-treatment such as waste liquid treatment.

When a series of wafer substrate processing is performed by applying the wafer cleaning method of the present invention, the foreign matter is sufficiently removed by the water polishing and cleaning step, so that acid or alkali is removed before polishing as in the prior art. This eliminates the necessity of chemical etching using a method and pre-cleaning using a large amount of a cleaning liquid after polishing.

When the final cleaning of the wafer substrate is performed after the completion of the polishing cleaning, residual abrasive particles on the wafer substrate surface,
Since most foreign matters such as particles, organic substances, and metal impurities are removed, the cleaning load in the final cleaning is reduced, the cleaning effect is improved, and a highly purified wafer substrate can be obtained. Further, since the conventional pre-cleaning step becomes unnecessary, the processing time of the wafer substrate can be shortened.

That is, in the present invention, the wafer substrate can be polished without being chemically etched, and after the polishing is completed, water polishing can be performed to lead to the final cleaning step. There is a great advantage that pre-cleaning after etching and polishing can be omitted.

According to a third aspect of the present invention, in the method for cleaning a wafer according to the first or second aspect, functional water obtained by performing a predetermined treatment on ultrapure water is used as the cleaning water. And

The present invention provides a wafer cleaning method capable of removing foreign substances on the surface of a semiconductor wafer more efficiently by using functional water as the cleaning water. Here, “functional water obtained by subjecting ultrapure water to a predetermined treatment” has a function of removing a specific foreign substance by performing a physical or chemical action on ultrapure water having an extremely low impurity concentration. Ultrapure water improved in this way, for example, megasonic irradiation ultrapure water, ozone additive ultrapure water, electrolytic ionic water or low dissolved oxygen water can be used.

Since ultrapure water has an extremely low impurity concentration, functional water obtained by subjecting ultrapure water to a predetermined treatment also has an extremely low impurity concentration and adheres to the surface of the semiconductor wafer based on the function resulting from the treatment. It has a function of taking in the foreign matter and separating it from the surface of the semiconductor wafer. Therefore, in the present invention, by performing water polishing cleaning using such functional water as cleaning water, it is possible to reduce residual foreign substances without foreign substances generated from the cleaning water itself adhering to the semiconductor wafer.

In addition, due to the strong foreign matter removing action of the functional water,
Foreign matter can be effectively removed. In other words,
Small particles that cannot be removed by conventional pre-cleaning,
Organic substances, residual abrasives, metal impurities, etc. are lifted from the surface of the semiconductor wafer by physical or chemical action by functional water, and are forcibly removed by the polishing means in such a state, so that foreign substances can be more effectively reduced. Can be done.

According to a fourth aspect of the present invention, in the method for cleaning a wafer according to the third aspect, the water polishing and cleaning step uses a plurality of types of different functional waters as the cleaning water.

According to the present invention, there is provided a wafer cleaning method capable of further improving the cleaning efficiency of a semiconductor wafer by using a plurality of types of different functional waters as the cleaning water in the water polishing cleaning as the first polishing means. I do.

Since the functional water used as the cleaning water of the present invention has different foreign substances that can be effectively removed depending on its type, by using a plurality of functional waters as the cleaning water, the foreign substance removing effect of each functional water can be improved. It can be demonstrated synergistically. Therefore, the cleaning effect on the surface of the semiconductor wafer can be further improved by a combination of a plurality of functional waters.

That is, the foreign matter to be removed is different depending on the state of the deposit on the surface of the semiconductor wafer. Therefore, it is possible to select a combination of functional waters optimal for the type of the foreign matter to be removed, thereby further improving the cleaning effect. Can be done.

For example, if it is considered that a long time is required for the mirror polishing process and a large amount of residual abrasives and organic substances such as wax are attached to the wafer substrate surface, such a large amount of organic substances are removed. Therefore, functional water having an excellent effect of removing organic substances and other functional water having an excellent effect of removing particles, metal impurities, and the like can be used as cleaning water.

According to a fifth aspect of the present invention, in the wafer cleaning method according to the third aspect, in the water polishing and cleaning step, a plurality of different functional waters are used as the cleaning water,
The method is characterized in that water polishing cleaning is performed by using these in a stepwise manner.

According to the present invention, a plurality of types of different functional waters are sequentially used in a stepwise manner to perform water polishing and cleaning, whereby the effect of removing foreign substances of a plurality of different functional waters can be exerted at different timings. . Therefore, the timing of removing foreign matter can be adjusted according to the state of foreign matter adhesion on the semiconductor wafer, and the cleaning effect on the semiconductor wafer surface can be improved.

For example, first, functional water having an excellent effect of removing organic substances is used as cleaning water in order to remove residual abrasive particles and organic substances adhering to the wafer substrate during the processing of the mirror polishing step. By cleaning using functional water having an excellent effect of removing metal impurities and the like as cleaning water, reattachment of organic substances can be prevented, further reduction of foreign substances can be achieved, and cleaning efficiency is improved. .

Preferred embodiments of the functional water used in the wafer cleaning method of the present invention are described below.

As a first aspect, in the method for cleaning a wafer according to any one of the third to fourth aspects, there is a method in which the functional water includes megasonic irradiation ultrapure water. Megasonic irradiated ultrapure water is 800kHz-3M
Ultra-pure water irradiated with ultrasonic vibration of Hz. Megasonic-irradiated ultrapure water removes particles on the surface of semiconductor wafers by high-pressure waves of cleaning water generated by ultrasonic vibration, and is excellent in removing particles, especially small particles, removing metal impurities, and removing organic substances. It is generally known that

In the present invention, particles, metal impurities and organic substances adhering to the surface of the semiconductor wafer can be further reduced by using the functional water including the megasonic irradiated ultrapure water as the cleaning water.

In the present invention, the structure of the functional water is not particularly limited as long as the functional water contains megasonic irradiation ultrapure water, and the functional water is mixed with other functional water or separately or simultaneously or sequentially selectively. Can be used as washing water.

In a second aspect, the above-mentioned claims 3 to
5. The method for cleaning a wafer according to any one of items 4, wherein the functional water includes ozone-added ultrapure water.

The ozone-added ultrapure water is functional water obtained by dissolving ozone generated when ultrapure water is electrolyzed into ultrapure water, and is generally excellent in removing metal impurities and organic substances. Is known. In the present invention, by using the functional water including the ozone-added ultrapure water as the cleaning water, metal impurities and organic substances attached to the surface of the semiconductor wafer can be further reduced.

In the present invention, as long as the functional water contains ozone-added ultrapure water, its structure is not particularly limited, and it may be mixed with other functional waters or separately or simultaneously or sequentially with washing water. It can also be used as Preferred embodiments of such a combination using ozone-added ultrapure water and another type of functional water are as follows.

For example, a semiconductor wafer can be polished and cleaned with megasonic irradiated ultrapure water as functional water, and then polished and cleaned with ozone-added ultrapure water. In these cases, metal impurities and organic substances can be further reduced by megasonic irradiation ultrapure water, in addition to removal of metal impurities and organic substances by ozone-added ultrapure water.

Further, a water obtained by megasonic vibration of ozone-added ultrapure water can be used as the functional water. In this case as well, particles, metal impurities and organic substances can be further reduced.

As a third aspect, in the wafer cleaning method according to any one of the third to fourth aspects, there is a method in which the functional water contains electrolytic ionic water.

Electrolytic ionic water is functional water obtained by electrolyzing ultrapure water containing ions. Acidic anode water generated on the anode side during electrolysis and alkaline cathode water generated on the cathode side during electrolysis. There is. Anode water is excellent in removing metal impurities, particularly Cu, and cathodic water is
It is generally known that it is excellent in removing particles.

In the present invention, by using the functional water containing the anode water as the cleaning water, metal impurities adhering to the semiconductor wafer surface can be further reduced. Further, in the present invention, by using the functional water including the cathode water as the cleaning water, it is possible to further reduce the organic substances attached to the surface of the semiconductor wafer.

Further, since the electrolytic ion water easily returns to water when left to stand, the use of functional water containing electrolytic ion water as the cleaning water facilitates waste liquid treatment after the water polishing and cleaning step. It is.

In the present invention, the structure is not particularly limited as long as the functional water contains electrolytic ionic water, and either one of anode water and cathode water can be used as washing water. . Also, the anode water and the cathode water can be used in a stepwise manner. Further, the electrolytic ionic water may be mixed with other functional water, or may be used as washing water simultaneously or sequentially step by step.
Preferred embodiments of such a combination using electrolytic ionic water and another type of functional water are as follows.

For example, a semiconductor wafer can be polished and cleaned with megasonic irradiated ultrapure water as functional water, and then polished and cleaned with anode water. In addition, the one obtained by subjecting the anode water to megasonic vibration can be used as the functional water. In these cases, in addition to the removal of metal impurities (including Cu) by anode water, particles, metal impurities and organic substances can be further reduced by megasonic irradiation ultrapure water.

In the next preferred embodiment, after the semiconductor wafer is polished and cleaned with cathode water as functional water,
Polishing and cleaning can be performed with ozone-added ultrapure water. Also, a mixture of ultrapure water with ozone added to the cathode water or a mixture of cathode water and ozone can be used as the functional water. In these cases, the particles can be further reduced by the cathode water, in addition to the removal of metal impurities and organic substances by the ozone-added ultrapure water.

As a fourth aspect, the above-mentioned claims 3 to
5. The method for cleaning a wafer according to any one of the items 4, wherein the functional water includes low dissolved oxygen water.

Low-dissolved oxygen water is a functional water in which dissolved oxygen in ultrapure water is reduced, is excellent in removing metal impurities, and removes a natural oxide film formed by the natural oxidation of a semiconductor wafer surface in air. It is generally known that the terminal of silicon (Si) atoms on the outermost surface of a wafer is replaced with hydrogen atoms.

In the present invention, by using functional water containing low-dissolved oxygen water as cleaning water, metal impurities adhering to the semiconductor wafer surface can be further reduced.
Further, by removing the natural oxide film on the surface of the semiconductor wafer, particles, organic substances and metal impurities can be further reduced.

In the present invention, the structure of the functional water is not particularly limited as long as the functional water contains low-dissolved oxygen water. The functional water is mixed with other functional water, or is washed separately or simultaneously or sequentially and selectively. It can also be used as water. Preferred embodiments of such a combination using low-dissolved oxygen water and another type of functional water are as follows.

For example, a semiconductor wafer can be polished and cleaned with megasonic irradiation ultrapure water as functional water, and then polished and cleaned with low-dissolved oxygen water. In these cases, particles can be further reduced by megasonic irradiation ultrapure water, in addition to reduction of metal impurities and organic substances by low dissolved oxygen water.

In the next preferred embodiment, after the semiconductor wafer is polished and washed with cathode water as functional water,
Polishing and cleaning can be performed with low dissolved oxygen water. Also,
Cathode water and low-dissolved oxygen water can be supplied simultaneously or mixed. In these cases, metal impurities and organic substances can be reduced by the low dissolved oxygen water, and particles can be further reduced by the cathode water.

As a fifth aspect, in the wafer cleaning method according to any one of the third to fourth aspects, there is a method in which the functional water includes electric resistance adjusting water.

Electric resistance adjusting water is functional water in which the concentration of dissolved carbon dioxide in ultrapure water is increased or controlled, and it is generally known that static electricity is removed. For this reason, by using the electric resistance adjusting water as the functional water, static electricity on the surface of the semiconductor wafer is removed during the cleaning. Adhesion can be prevented.

In the present invention, the structure is not particularly limited as long as the functional water contains the electric resistance adjusting water, and is mixed with other functional water, or separately or simultaneously or sequentially as washing water. Can also be used.

Preferred embodiments of the combination using the electric resistance adjusting water and another type of functional water are as follows.

For example, a semiconductor wafer can be polished and washed with megasonic irradiated ultrapure water as functional water, and then polished and washed with electric resistance adjusting water. Also, megasonic irradiation ultrapure water and electric resistance adjusting water can be supplied simultaneously or mixed. Furthermore, water obtained by megasonic vibration of electric resistance adjusting water can be used as functional water.

In these cases, particles, metal impurities and organic substances are removed by megasonic irradiation ultrapure water, and reattachment of particles to the semiconductor wafer surface is prevented by electric resistance adjusting water. Further, particles can be further reduced.

In the next preferred embodiment, as functional water, cathode water and electric resistance adjusting water can be supplied simultaneously or mixed. In this case, the particles and metal impurities are removed by the cathode water, and the particles can be prevented from re-adhering to the surface of the semiconductor wafer by the electric resistance adjusting water.

In the next preferred embodiment, after the semiconductor wafer is polished and cleaned with megasonic irradiated ultrapure water, ozone added ultrapure water and electric resistance adjusting water can be supplied simultaneously or mixed. In this case, particles, metal impurities and organic substances are removed by megasonic irradiation ultrapure water, and then particles, metal impurities and organic substances are further removed by ozone-added ultrapure water, and the electric resistance adjusting water is used. Further, it is possible to prevent particles from re-adhering to the surface of the semiconductor wafer.

In the next preferred embodiment, megasonic irradiation ultrapure water, anode water and electric resistance adjusting water can be supplied simultaneously or mixed. In this case, particles, metal impurities and organic substances are removed by megasonic irradiation ultrapure water, metal impurities (including Cu) are removed by anode water, and the particles are deposited on the semiconductor wafer surface by electric resistance adjusting water. Redeposition can be prevented.

In the next preferred embodiment, after the wafer substrate is polished and cleaned with megasonic irradiation ultrapure water, low-dissolved oxygen water and electric resistance adjusting water can be supplied simultaneously or mixed. In this case, particles, metal impurities and organic substances are removed by megasonic irradiation ultrapure water, a natural oxide film and metal impurities are removed by low-dissolved oxygen water, and the particles are further subjected to electric resistance adjustment water to remove the particles from the surface of the semiconductor wafer. Can be prevented from re-adhering.

The following preferred embodiments include cathode water,
Ozone-added ultrapure water and electric resistance adjusting water can be supplied simultaneously or mixed. In this case, the particles can be prevented from re-adhering to the surface of the semiconductor wafer by the electric resistance adjusting water, in addition to the removal of the particles by the cathode water and the removal of the metal impurities and the organic substances by the ozone-added ultrapure water.

The following preferred embodiments include cathode water,
The low-dissolved oxygen water and the electric resistance adjusting water can be supplied simultaneously or mixed. In this case, the particles can be prevented from re-adhering to the surface of the semiconductor wafer by the electric resistance adjusting water, in addition to the removal of the particles by the cathode water, the removal of the natural oxide film and the metal impurities by the low dissolved oxygen water.

Further, in the present invention, in the wafer cleaning method according to any one of claims 3 to 4, preferably, the water polishing and cleaning step is performed in a gas atmosphere which does not affect the function of the functional water. It is a good idea to do it inside.

That is, in the present invention, the polishing and cleaning of the semiconductor wafer in the water polishing and cleaning step is performed in a gas atmosphere which does not affect the function of the functional water, thereby adjusting the concentration of the functional water and cleaning the semiconductor wafer. The effect can be maintained.

Here, “a gas atmosphere that does not affect the function of the functional water” means that the foreign matter removing function of the functional water is maintained.
A gas atmosphere consisting of components that are not reduced, for example,
A gas comprising a component insoluble in functional water can be used.

That is, when a part or all of the gas component is dissolved in the functional water, the concentration of the functional water fluctuates, and the foreign matter removing action is reduced. Therefore, by performing the polishing and cleaning of the semiconductor wafer in a gas atmosphere composed of components insoluble in functional water, the cleaning effect of the functional water can be maintained.

For example, when the functional water as the cleaning water contains low dissolved oxygen water, the nitrogen gas is polished and cleaned so that the oxygen in the air dissolves in the functional water and the dissolved oxygen concentration in the functional water does not increase. Polishing and cleaning can be performed by filling the inside of the apparatus.

When the functional water as the washing water contains electric resistance adjusting water, CO ₂ gas is dissolved so that carbon dioxide in the air dissolves in the functional water and the concentration of dissolved carbon dioxide in the functional water does not fluctuate. Polishing and cleaning can be performed by filling the inside of the polishing and cleaning apparatus with clean air or nitrogen gas whose concentration is controlled.

Therefore, the concentration of functional water is kept constant by the water polishing / cleaning step of the present invention, so that foreign substances can be reduced without reducing the cleaning effect.

Next, a polishing means for polishing the surface of the semiconductor wafer, a holding means for holding the surface of the semiconductor wafer in contact with a polishing portion of the polishing means, and a polishing means Cleaning water supply means for supplying cleaning water consisting only of functional water subjected to a predetermined process to the contact surface of the semiconductor wafer, and keeping the cleaning water in contact with the surface of the semiconductor wafer. A wafer cleaning apparatus characterized in that the surface of a semiconductor wafer is polished and cleaned by polishing with a wafer.

The present invention is a preferred apparatus for carrying out the invention of claims 1 to 5, for example, in the case of a mirror-polished wafer substrate, the wafer substrate is polished by a polishing means, a holding means, and a cleaning water supply means. By polishing while the surface of the substrate is kept in contact with the cleaning water, it is possible to achieve higher cleaning than the conventional cleaning method using a pre-cleaning step.

The semiconductor wafer described here is not limited to a wafer substrate after mirror polishing, but also a wafer substrate after rough polishing in multiple stages of mirror polishing, a device CMP process, an SOI process and the like. It includes all wafer substrates that need to be cleaned, such as wafer substrates that have undergone another processing process.

In the present invention, the means for polishing the semiconductor wafer while the surface of the semiconductor wafer is in contact with the cleaning water is provided by interposing only the cleaning water between the surface of the semiconductor wafer to be polished and the polishing means. Means for polishing.

For example, this can be attained by polishing the surface of the wafer substrate which has been cut out from the semiconductor ingot and has been mirror-polished, while spraying only the cleaning water from the cleaning water supply means. In this polishing means,
No abrasive is used, and the same applies to the case of processing a plurality of wafers.

That is, in the wafer cleaning apparatus of the present invention,
The water polishing / cleaning means, which is the first polishing means, is a dedicated one used only with cleaning water containing no abrasive, and is capable of polishing the surface of a semiconductor wafer with water only and simultaneously cleaning with the cleaning water. it can.

The configuration of the polishing means is not particularly limited as long as it can polish the surface of the semiconductor wafer. However, in order to prevent the foreign matter from the slurry or the like from adhering to the surface of the semiconductor wafer and reducing the cleaning effect, the polishing means does not chemically polish the surface of the semiconductor wafer but buffs using a platen or the like. It is preferable that the material is polished mechanically.

The structure of the holding means is not particularly limited as long as it can hold the surface of the semiconductor wafer in contact with the polishing portion of the polishing means. It is preferable to be configured so that it can be polished.

For example, the polishing means is constituted by a rotatable rotary polishing table provided with a buff polishing member on the surface, and the holding means presses the surface of the semiconductor wafer against the rotary polishing table and maintains the state. Can be configured. In this case, the surface (polishing surface) of the semiconductor wafer facing the buff polishing member of the rotary polishing table can be polished by a mechanical method such as wiping.

Therefore, it is possible to forcibly remove foreign matter from the surface of the semiconductor wafer by mechanically polishing the surface of the semiconductor wafer by the polishing means while supplying only the cleaning water (water polishing). Become. Therefore, it is possible to remove foreign matters such as small particles that cannot be removed by the conventional wafer cleaning apparatus.

Further, the foreign matter once removed from the semiconductor wafer is forcibly removed by the polishing means and the washing water, and does not collect on the surface of the semiconductor wafer. Nor. Therefore, foreign substances such as residual abrasives, particles, organic substances, and metal impurities can be more effectively removed by the polishing means and the cleaning water supply means of the present invention.

Of course, by polishing the wafer substrate after mirror polishing with the polishing means and cleaning water supply means of the present invention, not only the conventional pre-cleaning is not required, but also the conventional pre-cleaning. In comparison, foreign substances such as residual abrasives, particles, organic substances, and metal impurities can be more effectively removed.

Further, in the present invention, the surface of the semiconductor wafer is cleaned using the cleaning water consisting of only the functional water subjected to the predetermined treatment from the cleaning water supply means. Here, “functional water subjected to a predetermined treatment” refers to ultrapure water having a function of diluting and removing foreign substances by applying physical or chemical action to ultrapure water having an extremely low impurity concentration. For example, depending on the type of foreign matter, megasonic irradiation ultrapure water,
Ozone additive ultrapure water, electrolytic ion water or low-dissolved oxygen water can be used.

Functional water generated from ultrapure water has an extremely low impurity concentration and has a function of diluting and removing foreign substances. Therefore, in the present invention, by performing the polishing and cleaning using such functional water as the cleaning water, it is possible to reduce foreign substances without causing foreign substances generated from the cleaning water itself to adhere to the semiconductor wafer.

When used for cleaning a wafer substrate after mirror polishing, small particles, organic substances, residual abrasives, metal impurities, etc., which cannot be removed by conventional pre-cleaning, are subjected to chemical action by functional water. As a result, the wafer is floated from the surface of the wafer substrate and is forcibly removed by the polishing means in such a state, so that foreign substances can be reduced more effectively.

Further, since the functional water is generated from ultrapure water, cleaning is performed using a chemical solution, and waste water treatment such as acid or alkali is required as compared with the conventional pre-cleaning. Etc. can be easily performed.

Here, the configuration of the cleaning water supply means is not particularly limited as long as it supplies cleaning water consisting only of functional water to the wafer substrate surface at the contact surface of the polishing means. . For example, the cleaning water supply means can be constituted by a nozzle or a slit line having a plurality of injection ports. Further, a tank for storing functional water can be further provided.

When a series of wafer processing is performed by applying the wafer cleaning apparatus of the present invention, the foreign substances are sufficiently removed, so that there is no need to perform the conventional pre-cleaning requiring a large amount of cleaning liquid.

In other words, the wafer substrate cleaned by the apparatus of the present invention is substantially free of foreign substances such as residual abrasives, particles, organic substances and metal impurities adhering to its surface. The cleaning load in the final cleaning of the substrate is reduced and the cleaning effect is improved, so that a highly purified wafer substrate can be obtained. Further, since the conventional pre-cleaning becomes unnecessary, the processing time of the wafer substrate can be reduced.

The invention according to claim 7 is characterized in that, in the wafer cleaning apparatus according to claim 6, the cleaning water supply means supplies a plurality of different functional waters.

[0117] Since the functional water has different foreign matter that can be effectively removed depending on the type, in the present invention, a plurality of functional waters are used as washing water by the washing water supply means in accordance with the foreign matter to be removed. Thereby, the cleaning effect on the surface of the semiconductor wafer can be improved.

Further, the cleaning water supply means can use a combination of functional waters having different diluting / removing functions for the foreign matter depending on the condition of the deposit on the surface of the semiconductor wafer at the end of the mirror polishing. The optimal functional water for removal can be selected, and the cleaning effect can be further improved.

The structure of the washing water supply means is not particularly limited as long as it can supply a plurality of functional waters. For example, a plurality of nozzles for injecting functional water and a storage tank for storing functional water corresponding to each nozzle can be provided for each functional water. Further, one nozzle may be provided, and a plurality of functional waters may be mixed and ejected from the nozzle. Further, in this case, it is possible to supply a plurality of functional waters from one nozzle in order.

According to an eighth aspect of the present invention, in the wafer cleaning apparatus according to the sixth or seventh aspect, the cleaning water supply means includes a functional water generating means for generating functional water.

According to the present invention, since the functional water generating means is provided in the cleaning water supplying means, the functional water can be generated and the semiconductor wafer can be cleaned while continuously supplying the functional water.
It is possible to avoid complicated replacement work of a storage tank for functional water or the like.

For example, when megasonic irradiated ultrapure water is used as the functional water, the functional water generating means may be a megasonic nozzle provided with a megasonic oscillator at an injection port such as a nozzle or a megasonic nozzle at a plurality of injection ports. A megasonic slit line provided with a sonic oscillator can be used. When using ozone-added ultrapure water as the functional water, an ozone water producing device or the like can be provided as the functional water generating means.

In the case where electrolytic ionic water is used as the functional water, a two- or three-tank type electrolytic ionic water producing apparatus or the like can be provided as the functional water generating means. When low-dissolved oxygen water is used as the functional water, a vacuum deaerator or a membrane deaerator can be provided as the functional water generating means. In the case where the electric resistance adjusting water is used as the functional water, a dissolved carbon dioxide control device or the like can be provided as the functional water generating means.

In the case where a plurality of functional waters are used, a plurality of functional water generating means can be provided for each functional water.

According to a ninth aspect of the present invention, in the wafer cleaning apparatus of the seventh or eighth aspect, the cleaning water supply means supplies a plurality of different functional waters at the same time.

In the present invention, since a plurality of different functional waters can be used simultaneously by the cleaning water supply means, the cleaning effect of the semiconductor wafer can be improved by the synergistic effect of the combination of the functional waters having different foreign substance removing actions. Can be.

For example, particles can be further reduced by megasonic irradiation of ozone-added ultrapure water, anode water or low-dissolved oxygen water as functional water.

The functional water may include cathode water and ozone-added ultrapure water, cathode water and low-dissolved oxygen water, cathode water and ozone-added ultrapure water and electric resistance-adjusted water, or cathode water and low-dissolved oxygen water and electric water. By combining the resistance adjusting water and the like, a plurality of functional waters can be simultaneously supplied, respectively, so that particles can be further reduced. The functions and effects achieved by these combinations are the same as the functions and effects described in the fifth aspect.

As the washing water supply means of the present invention, for example, a plurality of nozzles can be provided, and different functional water can be simultaneously jetted from each nozzle. Also, 1
One nozzle is provided, and multiple functional waters are mixed in advance,
It is also possible to configure such that mixed functional water is jetted from one nozzle.

[0130] The invention according to claim 10 is the invention according to claim 7 or 8.
Wherein the cleaning water supply means selectively supplies a plurality of different functional waters.

In the present invention, since a plurality of functional waters can be selectively supplied by the cleaning water supply means, a function most suitable for removing a large amount of foreign matter depending on the foreign matter adhesion state on the semiconductor wafer surface. Water can be selected for cleaning, and the cleaning effect of the semiconductor wafer can be improved.

For example, when a large amount of particles and metal impurities adhere to the surface of a semiconductor wafer, megasonic irradiation ultrapure water, which has an excellent effect of removing particles, and an excellent effect of removing metal impurities, etc. Ozone-added ultrapure water can be selected from a plurality of functional waters and used as washing water.

The invention according to claim 11 is the invention according to claim 7 or 8
Wherein the cleaning water supply means supplies a plurality of different functional waters in a predetermined order in a stepwise manner.

According to the present invention, a plurality of types of different functional waters are sequentially used in a stepwise manner to perform water polishing and cleaning, so that the effect of removing foreign substances of a plurality of different functional waters can be exerted at different timings. . Therefore, the timing of removing foreign matter can be adjusted according to the state of foreign matter adhesion on the semiconductor wafer, and the cleaning effect on the semiconductor wafer surface can be improved.

For example, after the megasonic irradiation ultrapure water is first supplied as functional water by the cleaning water supply means, the ozone added ultrapure water, anode water or low dissolved oxygen water can be supplied next. In this case, after removing particles adhering to the surface of the semiconductor wafer by megasonic irradiation ultrapure water supplied first, ozone added ultrapure water, anode water or low dissolved oxygen water supplied later. In addition, metal impurities and organic substances on the surface of the semiconductor wafer can be removed.

Further, after the cathode water is first supplied as functional water by the cleaning water supply means, ozone-added ultrapure water or low-dissolved oxygen water can be supplied. In this case, after removing particles on the surface of the semiconductor wafer with the initially supplied cathode water, metal impurities and organic substances on the surface of the semiconductor wafer are removed with the ozone-added ultrapure water or low-dissolved oxygen water supplied later. Can be removed.

Therefore, the cleaning water supply means of the present invention can improve the cleaning efficiency of the semiconductor wafer surface.

Further, as a preferred embodiment of the present invention, the above-described wafer cleaning apparatus further comprises a shut-off means for shutting off at least a processing space for semiconductor wafers from outside air, and the inside of the shut-off means is filled with a predetermined gas. It is good to have been done. That is, by filling the inside of the blocking means with a predetermined gas, it is possible to maintain a constant cleaning effect on the semiconductor wafer.

The shut-off means shuts off the processing space of the semiconductor wafer from the outside air, and the inside of the shut-off means is filled with a predetermined gas. Never contact. Here, a closed water polishing and cleaning chamber can be used as the blocking means.

The predetermined gas refers to a gas composed of a component which does not reduce the foreign matter removing function of the functional water, and a gas composed of a component insoluble in the functional water can be used. For example, as the predetermined gas, when the functional water as cleaning water contains low dissolved oxygen water or electric resistance adjusting water, nitrogen gas is used so that oxygen or carbon dioxide in the air does not dissolve in the functional water. can do.

Therefore, it is possible to prevent the concentration of the functional water from being reduced by dissolving the components in the air into the functional water.
The concentration of functional water is kept constant. Therefore, foreign matter can be reduced by the blocking means of the present invention and the gas filled in the blocking means without reducing the cleaning effect of the semiconductor wafer.

[0142]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing one embodiment of a wafer polishing and cleaning apparatus of the present invention.

This polishing and cleaning apparatus is provided with a finishing polishing section 2 in which a finishing polishing apparatus for receiving a wafer substrate in a state where a silicon ingot is cut into a plurality of pieces by a wire saw or an inner peripheral blade and lapping the wafer substrate and performs polishing is stored.
And a water polishing / cleaning unit 1 in which a wafer cleaning apparatus for receiving a polished wafer substrate and cleaning the surface thereof by water polishing is stored.

The final polishing section 2 and the water polishing / cleaning section 1 are separated from each other by a partition wall 3, and the chambers of the final polishing section 2 and the water polishing / cleaning section 1 are filled with nitrogen gas. The partition 3 is provided with first and second air conditioners 4a and 4b for always keeping each room clean.

The first air conditioner 4a is composed of a fan member connected to a nitrogen tank T, and is indicated by an arrow A in FIG.
As shown in the figure, a nitrogen gas, which is a clean gas, is introduced into the water polishing and cleaning unit 1 from the nitrogen tank T.

The second air conditioner 4b is provided in the partition wall 3 between the finish polishing section 2 and the water polishing / cleaning section 1, and a fan member (not shown) installed in a through hole penetrating the partition wall 3. ). This fan member draws gas from the water polishing / cleaning unit 1 into the finish polishing unit 2 as indicated by an arrow B in the drawing.

The wrapped wafer substrate W is placed in the holder 5
While being held by a, it is introduced into the finish polishing unit 2 through a preliminary chamber (not shown). In the finish polishing section 2, the wafer loader 6 takes out the wafer substrate W from the holder 5a and places the wafer substrate W on the transfer table 7.

When the wafer substrate W is placed on the transfer table 7, the finish polishing top ring 8 of the finish polishing apparatus sucks the wafer substrate W from the upper surface side and lifts the wafer substrate W from the transfer table 7, and finish polishing the surface plate. Move up 9

The surface plate 9 for finish polishing is rotated at a constant speed by a motor (not shown) around the center as a center of rotation.
A polishing cloth for mirror polishing is laid on the surface plate 9. Above the surface plate 9, a polishing liquid supply nozzle 9a provided in the polishing apparatus and supplying a polishing liquid to the surface plate 9 is arranged.

The finish polishing top ring 8 is lowered while sucking the wafer substrate W from the upper surface side, and presses the lower surface of the wafer substrate W against the polishing cloth. Since the polishing cloth rotates together with the platen 9, the rotation causes the lower surface of the wafer substrate W to be shaved by the synergistic action of the polishing cloth and the polishing liquid.

The top ring for finish polishing 8 gradually moves in the direction of arrow C in the figure while the lower surface of the wafer substrate W is pressed against the polishing cloth to polish the lower surface of the wafer substrate W for 10 minutes. Thereafter, the top ring 8 for finish polishing lifts the wafer substrate W while sucking the wafer substrate W from the upper surface side, and moves toward the underwater transfer device 10.

The underwater transport device 10 is provided over the finish polishing section 2 and the water polishing / cleaning section 1, and is provided with a water tank 11 filled with rinsing water, and immersed in the rinsing water in the water tank 11. A plurality of substantially cylindrical roll brushes 12, a jet nozzle (not shown) for flowing rinsing water in a direction opposite to the traveling direction of the wafer substrate W, and a motor (not shown) for rotating the roll brushes 12; It has.

The individual roll brushes 12 move the wafer substrate W
Are arranged in a direction perpendicular to the traveling direction of the wafer substrate W and are respectively arranged along the traveling direction of the wafer substrate W. Each of the roll brushes 12 rotates in the same direction by power from a motor (not shown), and transports the wafer substrate W placed thereon toward the water polishing and cleaning unit 1.

When the wafer substrate W is placed on the plurality of roll brushes 12, the top ring 8 for finish polishing stops the suction and transfers the wafer substrate W to the underwater transport device 10. The delivered wafer substrate W moves underwater on the roll brush 12 with the rotation of the brush, and is conveyed toward the water polishing and cleaning unit 1 side.

When the wafer substrate W moves from the finish polishing section 2 to the water polishing / cleaning section 1, the second air conditioner is used to prevent gas from the finish polishing section 2 from entering the water polishing / cleaning section 1. 4b is always the water tank 1 of the underwater transport device 10
Above 1, a gas flow is formed from the water polishing / cleaning unit 1 side to the finish polishing unit 2 side.

A wafer substrate transfer tank 13 is connected to the water polishing and cleaning unit 1 side of the underwater transfer device 10, and the wafer substrate W transferred on the roll brush 12 is immersed in water while the wafer substrate transfer tank 13 is immersed in the water. Handed over to

The water polishing / cleaning section 1 contains a wafer cleaning apparatus, and the water polishing / cleaning section 1 is always filled with clean nitrogen gas by a first air conditioner 4a as a second shielding means. I have.

The wafer substrate W transferred to the wafer substrate transfer tank 13 is suction-held from the upper surface side by the water polishing / cleaning top ring 14, and is lifted. At this time, cleaning water is always supplied to the surface by a shower (not shown). Therefore, even when the water polishing / cleaning top ring 14 holds the wafer substrate W by suction, the entire surface of the wafer substrate W is always in contact with the cleaning water. Therefore, the wafer substrate W is transported in a wet state, is suction-held by the water polishing and cleaning top ring 14, and is transferred onto the water polishing and cleaning platen 15.

The water polishing and cleaning surface plate 15 is rotated at a constant speed by a motor (not shown) with the center as a rotation center, and a polishing cloth for cleaning and polishing is laid on the surface plate.
Above the platen 15, two nozzles 14a and 14b for supplying cleaning water are arranged.

One of these nozzles 14a and 14b ejects LDO water (low dissolved oxygen water) as washing water, and the other 14b comprises a megasonic slit line having a plurality of injection ports provided with megasonic oscillators. , Blast megasonic irradiated ultrapure water.

The water polishing / cleaning top ring 14 is lowered while sucking the wafer substrate W from the upper surface while supplying the cleaning water, and presses the lower surface of the wafer substrate W against the polishing cloth.
Since the polishing cloth rotates together with the platen 15, the lower surface of the wafer substrate W is mechanically polished and cleaned by this rotation. At this time, separately from the washing water injection nozzles of the washing device top ring 14, two nozzles 14
Cleaning water is supplied from a and 14b.

The two nozzles 14a and 14b
Nozzle 1 that jets LDO water (low dissolved oxygen water)
The LDO water from the nozzle 4a is initially supplied to the platen 15, and after 3 minutes, the supply of the LDO water from the nozzle 14a is stopped, and at the same time, megasonic irradiation ultrapure water starts to spray from the nozzle 14b, and the cleaning is performed. The water switches from LDO water to megasonic irradiated ultrapure water.

After a lapse of 3 to 5 minutes, the water polishing / cleaning top ring rises while sucking the wafer substrate W from the upper surface side, pulls the wafer substrate W away from the surface plate 15, and moves to the receiving side of the underwater slider device 16. Moving.

The underwater slider device 16 has a slide structure in which the wafer substrate receiving side 16a is higher than the wafer substrate transfer side 16b.
Since a is always supplied with cleaning water from a cleaning water injection nozzle (not shown), the cleaning water always flows down from the wafer substrate receiving side 16a toward the transfer side 16b.

When the water polishing / cleaning top ring 14 places the wafer substrate W on the wafer substrate receiving side 16a of the underwater slider device 16, the wafer substrate W flows down to the wafer substrate transfer side 16b together with the cleaning water. The holder 5b is disposed on the wafer substrate transfer side 16b, and holds the wafer substrate W flowing with the cleaning water in contact with the cleaning water.

This holder 5b holds the wafer substrate W in contact with the cleaning water until the final cleaning step after the completion of the water polishing (not described in detail here), and immerses the wafer substrate W in water. The wafer substrate is transported to the next cleaning step, which is the next step.

[0167]

As described above, according to the present invention, it is possible to obtain a high-purity semiconductor wafer with improved cleaning effect, that is, with less foreign matter adhering to the surface than before.

Further, according to the present invention, the surface of the semiconductor wafer is cleaned by polishing only with cleaning water not using a polishing material. Therefore, the polishing material adheres to the conventional polishing means, and this is used for cleaning. Secondary contamination such as adhesion to a semiconductor wafer does not occur.

In the present invention, since the semiconductor wafer is cleaned using water (functional water) for cleaning, it is necessary to perform cleaning using a chemical solution and to treat waste liquid such as acid and alkali. Post-treatment such as waste liquid treatment is also easier than in the past.

In the present invention, foreign matters such as small particles which cannot be removed by the conventional cleaning method can be removed because the surface of the semiconductor wafer is forcibly removed by the polishing means and the washing water. . Of course,
The foreign matter once removed from the wafer substrate is forcibly removed by the polishing means, so that the foreign matter once removed does not adhere again to the wafer substrate surface.

Further, if a series of wafer substrate processing is performed by applying the wafer cleaning method of the present invention, the foreign matter can be sufficiently removed by the water polishing and cleaning step. Etching and pre-cleaning performed using a large amount of cleaning liquid can be omitted. In this case, not only the cycle time required for cleaning can be shortened, but also the cleaning efficiency can be increased with a small amount of cleaning liquid. Therefore, the apparatus as a whole can be made smaller than before, and the wafer manufacturing cost can be reduced.

When the final cleaning of the wafer substrate is performed after the completion of the polishing cleaning, foreign substances such as residual abrasives, particles, organic substances, and metal impurities on the surface of the wafer substrate are mostly removed. And the cleaning effect is improved, and a highly purified wafer substrate can be obtained. Further, since the conventional pre-cleaning step becomes unnecessary, the processing time of the wafer substrate can be shortened.

By performing cleaning and polishing other than mirror polishing, the effect of removing micro roughness on the wafer surface can be improved. Since pre-cleaning is unnecessary in wafer cleaning and functional water is used as a cleaning liquid, post-processing such as waste liquid processing is easy.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a wafer cleaning apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water polishing washing part 2 Finish polishing part 3 Partition wall 4a, 4b Air conditioner 5a, 5b Holder 6 Wafer loader 7 Transfer stand 8 Finish polishing top ring 9 Finish polishing surface plate 9a Polishing liquid supply nozzle 10 Underwater transport device 11 Water tank 12 roll Brush 13 Wafer substrate transfer tank 14 Top ring for water polishing and cleaning 14a, 14b Nozzle 15 Surface plate for water polishing and cleaning 16 Underwater slider device 16a Wafer substrate receiving side 16b Wafer substrate transfer side W Wafer substrate T Nitrogen tank

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Minoru Hidemin, 555 Nakanoya, Annaka-shi, Gunma Pref.

Claims (11)

[Claims] 1. A method for cleaning a surface of a semiconductor wafer for removing foreign matter and the like on a surface of the semiconductor wafer and improving fine roughness, etc., wherein the surface of the semiconductor wafer is cleaned without using an abrasive. A wafer cleaning method, comprising: a water polishing cleaning step of supplying only water and polishing in a state where the cleaning water is in contact with a polishing surface. 2. After lapping a surface of a wafer substrate cut from a semiconductor single crystal, the wafer substrate is removed for the purpose of removing foreign substances and the like and improving fine roughness on the mirror-polished surface of the wafer substrate. In a surface cleaning method, by using a polishing means different from the mirror polishing, only cleaning water is supplied to the mirror-polished surface of the wafer substrate without using an abrasive, and the cleaning water is supplied to the polished surface. A wafer cleaning method comprising a water polishing cleaning step of polishing in a state of contact. 3. A functional water obtained by subjecting ultrapure water to a predetermined treatment as said washing water.
Or the wafer cleaning method according to 2. 4. The wafer cleaning method according to claim 1, wherein a plurality of different types of functional water are used as the cleaning water in the water polishing and cleaning step. 5. The water polishing cleaning step according to claim 4, wherein in the water polishing cleaning step, a plurality of types of different functional waters are used as the cleaning water, and the water polishing cleaning is performed by sequentially using the functional water. Wafer cleaning method. 6. A polishing means for polishing a surface of a semiconductor wafer, a holding means for holding the surface of the semiconductor wafer in contact with a polishing portion of the polishing means, and a contact surface of the polishing means being predetermined. Cleaning water supply means for supplying cleaning water consisting of only the functional water subjected to the applied processing, and polishing the semiconductor wafer surface in a state where the cleaning water is in contact with the surface of the semiconductor wafer. A wafer cleaning apparatus for cleaning a wafer. 7. The wafer cleaning apparatus according to claim 6, wherein the cleaning water supply unit supplies a plurality of different functional waters. 8. The wafer cleaning apparatus according to claim 6, wherein the cleaning water supply unit includes a functional water generating unit that generates functional water. 9. The wafer cleaning apparatus according to claim 7, wherein the cleaning water supply unit supplies a plurality of different functional waters at the same time. 10. The wafer cleaning apparatus according to claim 7, wherein said cleaning water supply means selectively supplies a plurality of different functional waters. 11. The wafer cleaning apparatus according to claim 7, wherein the cleaning water supply unit supplies a plurality of different functional waters in a predetermined order in a stepwise manner.