JP3225273B2 - Comprehensive polishing equipment for wafer substrates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an overall wafer polishing apparatus for performing a mirror surface treatment and a high cleaning on the surface of a wafer substrate.

[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. The foreign substance adhering to the wafer substrate surface is removed by pre-cleaning in which the subsequent wafer substrate is immersed and final cleaning in which the pre-cleaned wafer substrate 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. Like this
If the final cleaning is performed in a state where foreign matter is adhered to the surface of the wafer substrate, there is a problem that the cleaning efficiency is reduced and a finally highly purified wafer substrate cannot be 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 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 an overall wafer substrate polishing apparatus capable of obtaining a highly purified wafer substrate with improved cleaning effect as compared with the conventional one, that is, with less foreign substances adhering to the surface than the conventional one. Its main purpose is to:

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

Further, another object of the present invention is to provide an apparatus for polishing a wafer substrate in which the surface of the 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.

Another object of the present invention is to provide an overall wafer substrate polishing 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.

Another object of the present invention is to provide an overall wafer substrate polishing apparatus which is smaller than the conventional apparatus as a whole and can reduce the manufacturing cost of the wafer substrate.

[0022]

In order to achieve the above object, a wafer substrate is polished according to the first aspect of the present invention.
The equipment uses a polishing material to polish the surface of the wafer substrate
A mirror polishing means for polishing and a different polishing means from the mirror polishing means.
Polishing means, wherein the mirror-polished wafer substrate is
The surface of the water is a functional water that has been subjected to a predetermined treatment in ultrapure water.
A water polishing means for performing water polishing in contact with
Transporting the processed wafer substrate to the mirror polishing means.
Conveying means and the wafer group treated with pre-Symbol mirror polishing means
At least the mirror side of the wafer substrate is ultra pure water or
In contact with functional water that has been subjected to a predetermined treatment to ultrapure water
A second transport unit that transports the water to the water polishing unit as it is
And a wafer substrate in a wrapped state.
On the other hand, mirror polishing of the wafer substrate surface by the mirror polishing means
After processing, the mirror surface is in contact with ultrapure water or functional water.
Transported while maintaining the condition,
This is to perform a water polishing process on the wafer substrate surface. The overall polishing apparatus for a wafer substrate according to the present invention is a lapping step (first step) of polishing the wafer substrate using an abrasive to flatten the unevenness of the wafer substrate surface generated at the time of cutting.
A mirror polishing step (second step) of polishing the surface of the wafer substrate wrapped in the lapping step to a mirror surface using an abrasive, and the mirror polishing by a different polishing means different from the mirror polishing. A water polishing step (third step) of polishing the surface of the wafer substrate, which has been mirror-polished in the step, in contact with functional water having been subjected to a predetermined treatment to ultrapure water; A final cleaning step of cleaning the polished wafer substrate in contact with the cleaning water (fourth step)
The overall polishing method for the wafer substrate including the steps of
It is a device suitable for.

That is, in the present invention, the wafer substrate planarized in the lapping step as the first step is not subjected to a chemical cleaning process such as chemical etching in the mirror polishing step as the second step. Then, the wafer is polished to a mirror surface using an abrasive, and further polished in a water polishing step, which is a third step, in a state in which the polished surface of the wafer substrate is brought into contact with cleaning water by another polishing means different from mirror polishing. And then the fourth
In the final cleaning step, which is the step (3), final cleaning is performed.

Thus, the micro-roughness of the wafer substrate surface can be improved and the foreign matter adhering to the wafer substrate surface can be removed without performing the processes of chemical etching, mirror polishing, pre-cleaning, and final cleaning subsequent to the conventional lapping process. The present invention provides a total polishing method for a wafer substrate that can perform the above.

The wafer substrate of the present invention may be a wafer substrate cut out of a silicon single crystal ingot, a wafer substrate during or after lapping, or a multi-stage mirror polishing using an abrasive, or during processing. Refers to all wafer substrates in the wafer processing process, such as later wafer substrates. Of course, the present invention can also be applied to patterned wafer substrates that have undergone a device CMP process and wafers with oxide films that have undergone an SOI process. It is.

The term “total polishing of a wafer substrate” in the present invention refers to all processing steps performed to finally make a slicing wafer substrate into a mirror-finished wafer substrate with high cleanliness. In the present invention, a lapping step (first step), a mirror polishing step (second step), a water polishing step (third step), and a final cleaning step (fourth step) are performed to obtain a mirror surface wafer substrate with high cleanliness. The wafer substrate is comprehensively polished by the four processing steps of the step (3).

In the lapping step, which is the first step, the upper and lower surfaces of the slashed wafer substrate are simultaneously polished together with a polishing liquid to flatten fine irregularities on the surface of the wafer substrate and to make the depth of processing strain uniform. And the thickness of the wafer is made uniform.

The lapping means at this time is not particularly limited as long as it is a means for flattening fine irregularities on the surface of the wafer substrate, making the depth of processing distortion uniform, and polishing so as to make the thickness of the wafer uniform. Although not limited, for example, the polishing surfaces are arranged in parallel in opposition to each other, and the upper and lower platens that rotate in the same direction or the opposite direction, and are arranged between the polishing surfaces of both platens and revolve between them. A lapping apparatus is provided which comprises a carrier and holds the wafer substrate on the carrier to cause the wafer substrate to move in a planetary motion between the polishing surfaces of both surface plates to polish both surfaces thereof.

In the mirror polishing step as the second step, the wafer substrate polished in the lapping step is mirror-polished as it is without performing chemical etching.
The configuration of the mirror polishing means at this time is not particularly limited as long as it mirror-polishes the surface of the wafer substrate using an abrasive, but examples thereof include a buff polishing apparatus using a platen or the like.

The abrasive may be, for example, a slurry in which a fine powder of SiO ₂ is mixed with an alkaline solution such as a NaOH system having a pH of about 9 to 13. Here, the abrasive is a mirror-finished one. If so, there is no particular limitation.

Further, in the third step of the water polishing step, the wafer substrate having been subjected to the mirror polishing step is brought into contact with functional water which has been subjected to a predetermined treatment to ultrapure water by another polishing means. The polishing removes residual abrasive particles such as a chemical solution used in the previous step, foreign particles such as particles, organic substances or metal impurities adhered to the surface during the processing in the previous step or during the transfer of the wafer substrate.

Here, "polishing while the polishing surface is in contact with functional water which has been subjected to a predetermined treatment with ultrapure water (hereinafter referred to as water polishing)" refers to the surface of the wafer substrate to be polished. This means that the surface of the wafer substrate is mechanically polished by interposing only functional water obtained by subjecting ultrapure water to a predetermined treatment to a polishing means.

This can be achieved, for example, by polishing the wafer substrate while spraying functional water onto the wafer substrate. In other words, in the water polishing step of the present invention, the wafer substrate surface can be polished by the polishing means and can be washed at the same time, and after using the polishing liquid containing the abrasive, only the functional water is used in the same polishing means. Unlike those that are washed away, 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 with water. However, the polishing means mechanically polishes the wafer substrate surface, not chemical polishing, in order to prevent foreign matters from the slurry or the like from adhering to the wafer substrate surface and diminishing the cleaning effect. Is preferred. 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 this water polishing, polishing is performed only with functional water obtained by performing a predetermined treatment on ultrapure water without using any abrasive. As a result, there is no danger of the conventional polishing material adhering (or remaining) on the wafer surface and contaminating the wafer surface.

Further, in the present invention, by using the functional water for the water polishing, foreign substances on the wafer substrate surface can be efficiently removed.

Here, “functional water obtained by subjecting ultrapure water to a predetermined treatment” refers to a function of removing specific foreign matter by applying physical or chemical action to ultrapure water having an extremely low impurity concentration. Refers to ultrapure water improved to have, for example, megasonic irradiation ultrapure water, ozone additive ultrapure water, electrolytic ion water, or low dissolved oxygen water.

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 wafer substrate surface based on the function resulting from the treatment. It has the function of taking in the foreign matter and pulling it away from the surface of the wafer substrate. Therefore, in the present invention, by performing water polishing using such functional water, foreign matter generated from the functional water itself does not adhere to the wafer substrate, and in addition to removal by mechanical polishing, foreign matter generated from the functional water itself is removed. It is possible to efficiently reduce the residual foreign matter by the taking action.

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 wafer substrate surface by the chemical action of functional water and are forcibly removed by the polishing means in such a state, so that foreign substances can be more effectively reduced. it can.

In the water polishing step, a plurality of different functional waters may be used. That is, the cleaning efficiency of the wafer substrate can be improved by using a plurality of types of different functional waters.

Since the foreign substances that can be removed effectively differ depending on the type of the functional water, the foreign substance removing effect of each functional water can be exhibited synergistically by using a plurality of functional waters. Therefore, the effect of cleaning the surface of the wafer substrate can be improved by combining a plurality of functional waters.

That is, the foreign matter to be removed differs depending on the state of the foreign matter adhered on the wafer substrate surface after the mirror polishing step. Therefore, it is possible to select a combination of functional waters optimal for the type of the foreign matter to be removed. In addition, the cleaning effect can be further improved.

For example, when it is considered that a long time is required for the mirror polishing process and that 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.

In this water polishing step, water polishing may be performed by sequentially using a plurality of different types of functional water in a stepwise manner. Thus, the effect of removing the foreign matter of a plurality of different functional waters can be exerted at different timings. For this reason, depending on the state of adhesion of foreign substances on the wafer substrate,
Since the timing of removing foreign matter can be adjusted,
The effect of cleaning the surface of the wafer substrate can be improved.

For example, first, functional water having an excellent effect of removing organic substances is used to remove residual abrasive particles and organic substances adhered to the wafer substrate during the mirror polishing process. Washing using functional water having an excellent effect of removing organic substances can prevent reattachment of organic substances, further reduce foreign substances, and improve washing efficiency.

The final cleaning step, which is the fourth step, is a step of performing final cleaning through a wafer processing process. This final cleaning step utilizes the action of the cleaning water flow of supplying the cleaning water while the wafer substrate is immersed in the cleaning tank, and the action of the chemical properties of the cleaning water.

The cleaning water contains a chemical solution adjusted to a high degree of cleanliness and rinse water. Specifically, the cleaning water is a mixture of an acid-based chemical solution such as hydrofluoric acid or hydrochloric acid and a hydrogen peroxide solution. Ultrapure water may be used as a mixed solution, a mixed solution of an alkaline chemical such as ammonium hydroxide and a hydrogen peroxide solution, a surfactant, and a rinsing water.

By passing through the final cleaning step, ultra-fine particles and metal adhering to the wafer substrate surface are further removed, and finally a highly-clean mirror-surface wafer substrate having chemical luster and no processing distortion is obtained. can get.

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

As a first aspect, in the above-described method for comprehensively polishing a wafer substrate, there is a method in which the functional water includes megasonic irradiated ultrapure water. Megasonic irradiated ultrapure water is ultrapure water irradiated with ultrasonic vibration of 800 kHz to 3 MHz. Megasonic irradiated ultrapure water removes particles on the wafer substrate surface by high-pressure waves of functional 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 wafer substrate surface can be further reduced by using the functional water including the megasonic irradiated ultrapure 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. It can also be used as functional water.

Further, as a second aspect, in the above-mentioned comprehensive polishing method for a wafer substrate, there is a method in which the functional water contains ozone-added ultrapure water.

The ozone additive ultrapure water is functional water obtained by dissolving ozone generated by electrolysis of ultrapure water in 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, metal impurities and organic substances attached to the wafer substrate surface can be further reduced.

In the present invention, the configuration is not particularly limited as long as the functional water contains ozone-added ultrapure water, and the functional water is mixed with other functional water or separately or simultaneously or sequentially selectively with functional 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 wafer substrate may be polished and cleaned with megasonic irradiation 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 above-mentioned comprehensive polishing method for a wafer substrate, 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, and is composed of acidic anode water generated on the anode side during electrolysis and alkaline cathode water generated on the cathode side. 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, metal impurities adhering to the wafer substrate surface can be further reduced. Further, in the present invention, by using functional water including cathode water, it is possible to further reduce organic substances adhering to the wafer substrate surface.

Since the electrolytic ion water easily returns to water when left untreated, the use of functional water containing electrolytic ion water as the functional water facilitates waste liquid treatment after the water polishing step. is there.

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

For example, a wafer substrate can be polished and cleaned with megasonic irradiation 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, the wafer substrate is polished and washed with cathode water as functional water, and then polished and washed 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, in the above-mentioned method for comprehensively polishing a wafer substrate, there is a method in which the functional water contains low-dissolved oxygen water. Low-dissolved oxygen water is functional water that reduces dissolved oxygen in ultrapure water, and has excellent removal of metal impurities.
It is generally known to remove a natural oxide film formed by the natural oxidation of the wafer substrate surface in air and to replace the terminal of silicon (Si) atoms on the outermost surface of the wafer substrate with hydrogen atoms. I have.

In the present invention, by using functional water containing low-dissolved oxygen water, metal impurities adhering to the wafer substrate surface can be further reduced. Further, by removing the natural oxide film on the surface of the wafer substrate, 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, and the functional water may be mixed with other functional water or 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 wafer substrate can be polished and cleaned with megasonic irradiation ultrapure water as functional water, and then polished and cleaned with low-dissolved oxygen water. In this case, megasonic irradiation ultrapure water can further reduce particles and metal impurities and organic substances due to low dissolved oxygen water.

In the following preferred embodiment, the wafer substrate is polished and washed with cathode water as functional water, and then polished and washed with low-dissolved oxygen water. Further, the cathode water and the 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 above-described method for comprehensively polishing a wafer substrate, 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, the static electricity on the wafer substrate surface is removed during the cleaning, and the foreign matter such as the particles once removed is recharged on the wafer substrate surface by the charging of the wafer substrate surface. Adhesion can be prevented.

In the present invention, the structure of the functional water is not particularly limited as long as the functional water contains the electric resistance adjusting water, and the functional water is mixed with other functional water or separately or simultaneously or sequentially selectively as functional 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 wafer substrate may be polished and cleaned with megasonic irradiation ultrapure water as functional water, and then polished and cleaned 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 wafer substrate 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, particles and metal impurities are removed by the cathode water, and the particles can be prevented from re-adhering to the wafer substrate surface by the electric resistance adjusting water.

In the next preferred embodiment, 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 ozone-added ultrapure water, and re-adhesion of particles to the wafer substrate surface is prevented by electric resistance adjusting water. be able to.

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 wafer substrate 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, the particles, metal impurities and organic substances are removed by megasonic irradiation ultrapure water, the natural oxide film and metal impurities are removed by low dissolved oxygen water, and the particles are deposited on the wafer substrate surface by electric resistance adjusting water. Redeposition can be prevented.

The next preferred embodiment includes cathode water,
Ozone-added ultrapure water and electric resistance adjusting water can be supplied simultaneously or mixed. In this case, in addition to the removal of particles by the cathode water, the removal of metal impurities and organic substances by the ozone-added ultrapure water, the re-adhesion of the particles to the wafer substrate surface can be prevented by the electric resistance adjusting 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 being re-adhered to the wafer substrate surface 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 above-mentioned method for comprehensively polishing a wafer substrate, preferably, the water polishing step is performed in a gas atmosphere which does not affect the function of the functional water.

That is, in the present invention, the polishing and cleaning of the wafer substrate in the water polishing step is performed in a gas atmosphere that does not affect the function of the functional water, thereby adjusting the concentration of the functional water and thereby improving the cleaning effect of the wafer substrate. 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. For this reason, the cleaning effect of the functional water can be maintained by performing the polishing and cleaning of the wafer substrate in a gas atmosphere composed of components insoluble in the functional water.

For example, when the functional water contains low-dissolved oxygen water, oxygen in the air is dissolved in the functional water, and a room (chamber) filled with nitrogen gas is provided so that the dissolved oxygen concentration in the functional water does not fluctuate. A water polishing step is performed in the parentheses).

When the functional water contains electric resistance adjusting water, the carbon dioxide gas concentration was controlled so that the carbon dioxide in the air dissolved in the functional water and the dissolved carbon dioxide concentration in the functional water did not fluctuate. The water polishing process is performed in a room (chamber) filled with clean air or nitrogen gas.

As a result, since the characteristics of the functional water are maintained, foreign substances can be reduced without reducing the cleaning effect.

From the above, the lapping step (first step), mirror polishing step (second step), water polishing step (third step), and final cleaning step (fourth step) of the present invention are described. 4
The total polishing in one processing step makes it possible to more effectively remove residual abrasives, particles, organic substances, or more than the conventional five-step lapping, chemical etching, mirror polishing, pre-cleaning, and final cleaning steps. Not only can foreign matter such as metal impurities be removed,
Since the number of steps is smaller than that of the conventional general polishing, the processing time of the wafer can be reduced.

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

In the water polishing step of the present invention, polishing is performed by supplying only functional water without using any abrasive in the polishing process. As a result, there is no risk that the abrasive material adheres (or remains) to the wafer substrate surface and contaminates the wafer substrate surface as in the related art.

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

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

Further, in the present invention, since the surface of the wafer substrate is cleaned using functional water, the surface of the wafer substrate is cleaned using a chemical solution to perform a waste liquid treatment such as an acid or alkali treatment. Post-processing is also facilitated.

Since the wafer substrate to be cleaned in the final cleaning step has most of foreign substances such as residual abrasives, particles, organic substances and metal impurities on its surface removed, the cleaning load in the final cleaning is reduced. At the same time, the cleaning effect is improved, and a highly purified wafer substrate can be obtained.

[0095]

The present invention relates to the above-described comprehensive polishing of a wafer substrate.
An apparatus suitable for carrying out the method , wherein the surface of the wafer substrate after the lapping treatment is mirror-polished using an abrasive by a mirror polishing means, and the surface of the wafer substrate is predetermined in ultrapure water by a water polishing means. It was treated by polishing in the state in contact with the functional water obtained by facilities and the subsequent chemical etching after conventional lapping, mirror polishing, than overall polishing of the wafer substrate undergoing the process of pre-cleaning, the wafer substrate surface It is said that the micro-roughness is improved and the ability to remove foreign substances attached to the surface of the wafer substrate is improved.

The mirror polishing means is for mechanically polishing the wafer substrate after the lapping process using an abrasive.
The configuration is not particularly limited. For example, a buff polishing apparatus using a platen or the like may be used as the mirror polishing means. A rotary polishing table capable of holding and rotating the wafer substrate by suction; and a buff polishing member capable of pressing the wafer substrate and rotating in a direction opposite to the rotation direction of the rotary table, between the rotary polishing table and the buff polishing member. A configuration in which the surface of the sandwiched wafer substrate is buff-polished together with an abrasive material is exemplified.

With such a mirror polishing means, the wafer substrate surface is mirror-finished while reducing the roughness of the wafer substrate surface, that is, micro-roughness such as ripple and haze. In addition, as the abrasive, there is a liquid such as a slurry, but here, there is no particular limitation as long as the surface is finished in a mirror surface.

The water polishing means is for polishing the surface of the wafer substrate after the mirror polishing while being in contact with the functional water by another different water polishing means, and its configuration is not particularly limited. . However, the water polishing means mechanically removes the surface of the wafer substrate such as a buff polishing apparatus using a platen or the like in order to prevent foreign substances from the slurry or the like from adhering to the surface of the wafer substrate and thereby reducing the cleaning effect. Preferably, it is polished.

Here, "polishing while the cleaning water is in contact with the surface of the wafer substrate (water polishing)" means that only functional water is interposed between the surface of the wafer substrate to be polished and the water polishing means. This means that the surface of the wafer substrate is polished, and this can be achieved, for example, by polishing the wafer substrate while spraying functional water onto the wafer substrate. That is,
In this water polishing means, the surface of the wafer substrate can be polished with water and simultaneously washed with functional water.

That is, by mechanically polishing the wafer substrate surface in a state where only the functional water is brought into contact with the wafer substrate surface without using any abrasive by the water polishing means, the foreign matter can be mechanically removed. At the same time, chemical removal by the chemical action of functional water becomes possible. For this reason, the overall wafer substrate polishing apparatus of the present invention can remove foreign substances such as extremely small particles that cannot be removed by a conventional wafer cleaning apparatus.

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

Therefore, the water polishing means of the present invention makes it possible to more effectively remove foreign substances such as residual abrasives, particles, organic substances and metal impurities as compared with conventional chemical etching and pre-cleaning.

The first transfer means transfers the wrapped wafer substrate to the mirror polishing means. Preferably, the first transfer means prevents an oxide film from being formed on the surface of the wafer substrate and adhesion of foreign matter. In order to transport the wafer, the wafer is preferably transported in a state where the surface of the wafer is in contact with functional water. As such a device, for example, an apparatus including a water tank, a wafer holder provided in the water in the water tank, and a conveyor for transporting the wafer holder in a state of being immersed in the water is exemplified.

Further, in the present invention, the wafer substrate processed by the mirror polishing means by the second transfer means is transferred to the water polishing means. The second transfer means transfers the wafer substrate from the mirror polishing means to the water polishing means without causing dust and dirt, small particles, organic matter, residual abrasives, metal impurities, and the like to adhere to the wafer substrate surface. is there. As such, for example, at least the mirror side of the wafer substrate,
One that transports ultra-pure water or functional water that has been subjected to a predetermined treatment to ultra-pure water while maintaining the state in contact therewith is included.

By providing such first and second transfer means, the mirror polishing and cleaning of the wafer substrate can be realized continuously, so that the mirror polishing and cleaning of the wafer substrate can be efficiently performed.

Here, “functional water that has been subjected to a predetermined treatment” refers to ultra-pure water having an extremely low impurity concentration, which has a function of removing foreign substances by physical or chemical action. Pure water, for example, megasonic irradiated ultrapure water, ozone additive ultrapure water, electrolytic ionic water, or low dissolved oxygen water can be used depending on the type of foreign matter.

Further, since the functional water is generated from ultrapure water, it is cleaned by using a chemical solution, and compared with the conventional pre-cleaning which requires the treatment of a waste liquid such as an acid or an alkali, compared with the conventional pre-cleaning. Etc. can be easily performed.

Here, the means for supplying functional water to the water polishing means (hereinafter referred to as functional water supply means) may be any means for supplying functional water to the contact surface of the water polishing means. The configuration is not particularly limited. For example, it 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.

Since the functional water has different foreign substances that can be effectively removed depending on its type, the functional water supply means may supply a plurality of different functional waters simultaneously or selectively. Depending on the state of adhesion of the foreign substances on the wafer substrate surface, it is possible to select and clean the functional water most suitable for removing the foreign substances having a large amount of adhesion, thereby improving the cleaning effect of the wafer substrate.

That is, the functional water supply means configured to simultaneously or selectively supply a plurality of different functional waters depends on the state of the deposit on the wafer substrate surface at the end of the mirror polishing of the wafer substrate for the cleaning effect. Since it is possible to use a combination of functional waters having different foreign substance removing actions, it is possible to select the optimal functional water for removing foreign substances,
The cleaning effect can be further improved.

The configuration of the functional water supply means in this case is not particularly limited as long as it can simultaneously or selectively 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. Moreover, you may comprise so that several functional water may be supplied in order from one nozzle.

Further, the functional water supply means may include a functional water generating means for generating functional water. Thus, the polishing and cleaning of the wafer substrate can be performed while the functional water is being generated and continuously supplied, so that a complicated replacement operation of the storage tank for the functional water or the like can be avoided.

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 the ozone-added ultrapure water is used as the functional water, an ozone water producing device or the like can be provided as the functional water generating means.

When 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.

When a plurality of functional waters are used, a plurality of functional water generating means can be provided for each functional water.

When the functional water supply means simultaneously supplies a plurality of different functional waters, the cleaning effect of the wafer substrate is improved by a synergistic effect of a combination of 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 be cathode water, ozone-added ultrapure water, cathode water and low-dissolved oxygen water, cathode water, ozone-added ultrapure water and electric resistance adjusting water, or cathode water, 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 operational effects achieved by these combinations are the same as the operational effects described in claim 1.

Further, as a preferred embodiment of the present invention, the above-described overall polishing apparatus for a wafer substrate further comprises a blocking means for blocking at least a processing space of the wafer substrate from outside air,
Preferably, the inside of the blocking means is filled with a predetermined gas. 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 wafer substrate.

The shut-off means shuts off the processing space of the wafer substrate 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 is 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 decreasing due to the dissolution of the components in the air into the functional water.
The concentration of functional water is kept constant. Therefore, foreign matter can be reduced without reducing the cleaning effect of the wafer substrate by the blocking means of the present invention and the gas filled in the blocking means.

As described above, when a wafer is processed using the wafer substrate comprehensive polishing apparatus of the present invention, foreign substances are sufficiently removed. Therefore, conventional chemical etching using a strong acid or strong alkali, cleaning solution It is not necessary to perform pre-cleaning which requires a large amount of.

When the final cleaning of the wafer substrate is performed after the completion of the water 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 conventional chemical etching and pre-cleaning are not required, it is possible to shorten the wafer processing time.

According to a second aspect of the present invention, in the apparatus for polishing a wafer substrate according to the first aspect , the mirror polishing means, the water polishing means, and the first and second transfer means are respectively controlled. And a timing for transferring the wafer substrate from the first transfer means to the mirror polishing means, and transferring and setting the wafer substrate from the second transfer means to the water polishing means. The timing is roughly matched, and the transport time by the second transport unit is
A series of steps from the mirror polishing of the wafer substrate by the mirror polishing to the water polishing by the water polishing are set continuously so as to be shorter than the processing time by the mirror polishing or water polishing. It is characterized by performing.

In other words, the apparatus further comprises control means for controlling the mirror polishing means, the water polishing means, and the first and second transfer means, respectively. This has the advantage that the continuous mirror polishing and water polishing can be efficiently performed.

Further, the time from when the first transfer means receives and transfers the wafer substrate to the time when it is placed on the mirror polishing means, and when the second transfer means receives and transfers the wafer substrate from the mirror polishing means, is subjected to water polishing. The time to install it in the means,
By controlling the control means so that the mirror polishing processing time of the mirror polishing means and the water polishing processing time of the water polishing means substantially match, there is an advantage that continuous processing can be efficiently performed while sequentially feeding wafer substrates. .

[0129] In total the polishing apparatus of the wafer substrate of the present invention, the second conveying means, at least the mirror side of the wafer substrate processed by the mirror polishing means, predetermined ultrapure water or ultrapure water it is characterized in that for conveying while maintaining the state of contact with the functional water has facilities for processing.

That is, according to the present invention, the second transport means transports at least the mirror side of the wafer surface mirror-finished by the mirror polishing means in contact with ultrapure water or the functional water and transfers the wafer substrate to the water polishing means. It shall be handed over. As a result, when the wafer substrate is transported without being brought into contact with the functional water, a problem that hinders the high cleaning of the wafer substrate, that is, oxidation of the surface of the wafer substrate proceeds, and foreign matters such as dust and dust floating in the air are prevented. There is no problem such as adhesion.

The configuration of such a second transfer means is not particularly limited as long as the wafer substrate after mirror polishing is transferred in contact with functional water and transferred to the water polishing means. For example, a roll feed mechanism provided with a plurality of roll brushes arranged in parallel in the feed direction as a feed mechanism, and provided by immersing the feed mechanism in a water tank filled with functional water, or the like.

[0132]

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 the overall wafer substrate polishing apparatus of the present invention.

This overall polishing apparatus is roughly divided into a mirror polishing section 2 containing a mirror polishing apparatus constituting a mirror polishing step and a water polishing section 1 containing a water polishing apparatus constituting a water polishing step. A wafer loader 6, which is a first transfer means for taking out a wafer substrate in a state where a silicon igot is cut into a plurality of pieces by a wire saw or an inner peripheral blade and lapping the wafer substrate from the holder 5a and transferring the wafer substrate to a mirror polishing apparatus; An underwater transfer device 10 as a second transfer means for receiving a wafer substrate polished by the device and transferring the wafer substrate to a water polishing device is provided, and a series of mirror polishing and cleaning lines are formed.

The mirror polishing section 2 and the water polishing section 1 are separated from each other by a partition 3, and the chambers of the mirror polishing section 2 and the water polishing section 1 are filled with nitrogen gas. This partition 3
Are 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, nitrogen gas, which is a clean gas, is introduced into the water polishing section 1 from the nitrogen tank T.

The second air conditioner 4b is provided in the partition wall 3 between the mirror polishing section 2 and the water polishing section 1, and a fan member (not shown) installed in a through hole passing through the partition wall 3. It has. This fan member draws gas from the water polishing section 1 into the mirror polishing section 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 mirror polishing unit 2 through a preliminary chamber (not shown). The mirror polishing unit 2 houses a mirror polishing apparatus including a mirror polishing top ring 8, a mirror polishing platen 9, and a polishing liquid supply nozzle 9a.

The wafer substrate W introduced into the mirror polishing unit 2
Is taken out of the holder 5 a by the wafer loader 6 and placed on the delivery table 7. Wafer substrate W on delivery table 7
Is placed, the mirror-polishing top ring 8 sucks the wafer substrate W from the upper surface side and lifts it from the delivery table 7,
It is moved onto the mirror polishing surface plate 9.

The mirror polishing platen 9 is rotated at a constant speed by a motor (not shown) about the center as a center of rotation, and a polishing cloth for mirror polishing is laid on the platen 9. Above the platen 9, a polishing liquid supply nozzle 9 a for supplying a polishing liquid to the platen 9 is arranged.

The mirror polishing top ring 8 is used for the wafer substrate W.
Is sucked from the upper surface side, and the lower surface of the wafer substrate W is pressed 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 mirror polishing top ring 8 is gradually moved in the direction of arrow C in the drawing 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 mirror polishing top ring 8 is lifted in a state where the wafer substrate W is sucked from the upper surface side, and the underwater transfer device 1 is moved.
Move to 0 side.

The underwater transport device 10 is provided over the mirror polishing section 2 and the water polishing 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. Have.

[0143] Each roll brush 12
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. The wafer substrate W is rotated in the same direction by power from a motor (not shown), and is transported toward the water polishing unit 1.

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

When the wafer substrate W moves from the mirror polishing section 2 to the water polishing section 1, the second air conditioner 4 b is operated so that gas from the mirror polishing section 2 does not enter the water polishing section 1. A gas flow is always formed above the water tank 11 of the underwater transport device 10 from the water polishing section 1 to the mirror polishing section 2.

A wafer substrate delivery tank 13 is connected to the water polishing section 1 side of the underwater transfer device 10.
The wafer substrate W transported on the wafer 2 is delivered to the wafer substrate delivery tank 13 while being immersed in water.

In the water polishing section 1, a water polishing apparatus having a water polishing top ring 14, a water polishing platen 15, and two nozzles 14a and 14b for supplying functional water is stored. Further, the inside is always filled with clean nitrogen gas by the first air conditioner 4a as the second shielding means.

The wafer substrate W transferred to the wafer substrate transfer tank 13 is sucked and held from the upper surface side by the water polishing top ring 14 and pulled up. At this time, functional water is constantly supplied to the surface by a shower (not shown). Therefore, even when the top ring for the water polishing apparatus sucks and holds the wafer substrate W, the entire surface of the wafer substrate W is always in contact with the functional water. Accordingly, the wafer substrate W is transported in a wet state, is suction-held by the water polishing top ring 14, and is transferred onto the water polishing surface plate 15.

The water polishing surface plate 15 is rotated at a constant speed by a motor (not shown) with the center as a center of rotation, and a polishing cloth for cleaning and polishing is laid on the surface plate. Also,
Two nozzles 1 for supplying functional water are provided above the surface plate 15.
4a and 14b are arranged.

One of these nozzles 14a and 14b emits LDO water (low-dissolved oxygen water) as functional 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.

While supplying the functional water, the water polishing top ring 14 descends 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 15, the lower surface of the wafer substrate W is mechanically polished and cleaned by this rotation.
At this time, apart from the injection of the functional water, the two nozzles 14a, 14a, 1
Functional water is supplied from 4b.

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

Thereafter, the water polishing top ring rises while sucking the wafer substrate W from the upper surface side, separates the wafer substrate W from the surface plate 15 and moves to the receiving side of the underwater slider device 16.

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 supplied with functional water from a functional water jet nozzle (not shown), functional water always flows down from the wafer substrate receiving side 16a toward the transfer side 16b.

When the water polishing apparatus 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 functional water. The holder 5b is provided on the wafer substrate transfer side 16b, and holds the wafer substrate W flowing with the functional water in contact with the functional water.

The holder 5b holds the wafer substrate W in contact with functional water until the final cleaning step after the completion of 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.

[0157]

As described above, according to the present invention, the conventional lapping process, chemical etching process, mirror polishing process, It is possible to remove foreign substances such as residual abrasives, particles, organic substances or metal impurities more effectively than the general polishing by five steps of a polishing step, a pre-cleaning step, and a final cleaning step. Since the number of steps is smaller than that of polishing, the processing time of the wafer substrate can be reduced. In addition, since only a small amount of cleaning liquid is used, the time and cost required for a single polishing process of the wafer substrate can be reduced.

In addition, the chemical etching and mirror polishing pre-cleaning processes following the conventional lapping can be omitted, so that the surface of the wafer substrate is corroded by an acid or an alkali or a large amount of a strong acid or a strong alkali is discharged as a waste liquid. For example, various problems caused by conventional chemical etching and pre-cleaning do not occur. Of course, since functional water is used as the cleaning liquid, post-treatment such as waste liquid treatment is also easy.

In the present invention, since the wafer substrate surface is polished by the polishing means simultaneously with the cleaning of the wafer substrate surface, foreign substances such as extremely small particles which cannot be removed by the conventional wafer substrate cleaning method are removed. It is possible to further reduce the micro roughness of the wafer substrate surface.

Since the wafer substrate to be cleaned in the final cleaning step has most of foreign substances such as residual abrasives, particles, organic substances and metal impurities on its surface removed, the cleaning load in the final cleaning is reduced. At the same time, the cleaning effect is improved, and a highly purified wafer substrate can be obtained.

Further, since the number of processing steps is small, there is an advantage that the apparatus as a whole is smaller than before and the wafer substrate manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of a total polishing apparatus for a wafer substrate of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water polishing part 2 Mirror polishing part 3 Partition wall 4a, 4b Air conditioner 5a, 5b Holder 6 Wafer loader 7 Transfer stand 8 Mirror polishing top ring 9 Mirror polishing surface plate 9a Polishing liquid supply nozzle 10 Water transport device 11 Water tank 12 Roll brush 13 Wafer Substrate Delivery Tank 14 Top Ring for Water Polishing 14a, 14b Nozzle 15 Surface Plate for Water Polishing 16 Underwater Slider 16a Wafer Substrate Receiving Side 16b Wafer Substrate Delivery Side W Wafer Substrate T Nitrogen Tank

Continuation of the front page (72) Inventor Minami Minami 555 Nakanoya, Annaka-shi, Gunma 1 Super Silicon Laboratories Co., Ltd. (56) References JP-A-8-279483 (JP, A) JP-A-8-279 117703 (JP, A) JP-A-63-221967 (JP, A) JP-A-64-18228 (JP, A) JP-A-63-267159 (JP, A) JP-A-3-198332 (JP, A) 62-39967 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/304 621 H01L 21/304 622

Claims (2)

(57) [Claims] An abrasive is used on the surface of a wafer substrate.
Mirror polishing means for performing mirror polishing by means of a different polishing means different from the mirror polishing means,
The surface of the mirror-polished wafer substrate is cleaned with ultrapure water.
Water in contact with functional water that has been treated in advance
Water polishing means for polishing, and the wafer substrate subjected to the lapping processing to the mirror polishing means
A first conveying means for conveying the wafer substrate processed in the previous SL mirror polishing means, the wafer
At least the mirror side of the substrate is previously determined to be ultrapure water or ultrapure water.
Water while maintaining contact with the treated functional water.
A second transfer means for transferring to the polishing means , wherein the mirror
Mirror polishing of the wafer substrate surface was performed by surface polishing means
After that, the mirror side was kept in contact with ultrapure water or functional water
The wafer substrate is continuously transported by the water polishing means.
Wafer synthesis characterized by performing water polishing on the surface
Polishing equipment . 2. The apparatus according to claim 1, further comprising control means for controlling said mirror polishing means, said water polishing means, and said first and second transport means, respectively, wherein said wafer is transferred from said first transport means to said mirror polishing means. The timing at which the substrate is transported and installed is substantially matched with the timing at which the wafer substrate is transported and installed from the second transporting means to the water polishing means, and the transporting time by the second transporting means is It is set so as to be shorter than the processing time by the mirror polishing means or the water polishing means, and from the mirror polishing of the wafer substrate by the mirror polishing means,
2. The integrated wafer polishing apparatus according to claim 1 , wherein a series of steps over a water polishing process by said water polishing means are continuously performed.