JPH10335275A - Wafer surface cleaning method and integrated wafer polishing and cleaning apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the surface of a wafer substrate very clean through processes where pre- cleaning is eliminated, by a method wherein a polishing pad provided with flow paths where cleaning water flows through and which extend from its center toward periphery is used in a process where the surface of the wafer substrate is polished with only cleaning water, which contains no abrasive agent and is supplied onto it. SOLUTION: In a water polishing cleaning process, cleaning water fed between the surface of a wafer substrate 10 and the polishing plane of a polishing cleaning pad 22 from above the cleaning pad 22 is moved toward the periphery of the plane of the pad 22 by a centrifugal force induced by the rotation of a platen. At this point, cleaning water flowing into grooves S is discharged out of the cleaning plane of the pad 22 flowing along the grooves toward the periphery of the cleaning plane of the pad 22, and foreign matter removed from the surface of the wafer substrate 10 and attached to the pad 22 are discharged out together with the flow of cleaning water. By this setup, even if the wafer substrate 10 is large in diameter, a problem that the substrate 10 is contaminated again with foreign objects left between the surface of the substrate 10 and the polishing plane of the pad 22 is solved, so that the surface of the wafer substrate 10 can be made very clean after it is subjected to cleaning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a polishing apparatus capable of discharging foreign matters, contaminants, particles and the like from the surface of a wafer in a water polishing cleaning of a semiconductor wafer substrate.

[0002]

2. Description of the Related Art In a general semiconductor wafer manufacturing process, first, a silicon single crystal ingot is sliced to a constant thickness by a wire saw, an inner peripheral blade or the like to obtain a wafer substrate. Since the surface of this wafer substrate has irregularities caused by slicing and the thickness of the wafer substrate is not uniform, lapping is performed to flatten the surface irregularities and equalize the depth of processing strain. Thus, the thickness of the wafer substrate is uniformly adjusted.

[0003] A processing strain layer is formed on the wafer substrate after lapping by processing, and fine metal, polishing powder, silicon dust, and other particles adhere to the processing strain layer. Etching is performed by a chemical corrosion method using a strong acid, hydrofluoric acid, or the like.

[0004] After etching, the wafer substrate is subjected to alkali neutralization of the acid adhering to the surface, washed with water and dried,
One side is mirror-polished. Usually, mirror polishing includes two-step polishing of rough polishing and finish polishing, and finally, improvement of micro roughness, which is fine surface roughness by finish polishing,
After removing the haze, the process proceeds to the final washing step.

[0005] Such polishing is performed, for example, by attaching a polishing pad on a turntable and supplying a polishing agent while applying a constant load and a relative speed between the wafer surface and the polishing pad. As the polishing pad, for example, a foamed polyurethane sheet or a polishing cloth obtained by impregnating a nonwoven fabric such as polyester with polyurethane has been conventionally used.

The degree of cleanliness on the surface of a semiconductor wafer affects the characteristics of semiconductor devices. If the degree of cleanliness decreases, it causes a failure in forming a device pattern or adversely affects the electrical characteristics of the semiconductor devices. The decrease in the cleanliness of the wafer substrate surface is caused not only by micro-roughness, but also by particles, metal impurities, organic contaminants and other contaminants adhering to the substrate surface in the course of surface processing, and adhesion of oxide films containing the impurities on the polished surface. caused by.

Therefore, in order to obtain a high-cleanliness surface free of contaminants as much as possible after the final cleaning, conventionally,
In order to reduce the contamination in the final cleaning and reduce the load in the final cleaning, a pre-cleaning step is provided after the mirror polishing, and the pre-cleaning is followed by the final cleaning step.

The conventional pre-cleaning mainly comprises immersing a wafer substrate in a cleaning bath, supplying cleaning water into the cleaning bath and causing the cleaning water to overflow, while washing off contaminants on the substrate surface by the water flow. It is. After the pre-cleaning, the wafer substrate is housed in a carrier, dried with the carrier, and then sent to a final cleaning step.

[0009]

However, the conventional processes as described above have the following problems. First, in the etching after the lapping treatment, not only a large amount of a chemical substance is required, but also a large amount of electric power is required to obtain a high temperature required for the reaction, resulting in an increase in cost. In the pre-cleaning, not only a large amount of cleaning water is required, but also there is a possibility that contaminants may re-adhere to the surface of the wafer substrate, or contaminants may accumulate in the tank. Also,
Transfer is required for delivery to the final polishing step after pre-cleaning, and measures must be taken to prevent intermediate deterioration of the wafer substrate surface due to drying during that time. there were.

Therefore, at present, such a pre-cleaning is omitted, and a cleaning for reducing contaminants other than the mirror polishing is performed in the polishing process so that the wafer substrate can be directly transferred from the mirror polishing process to the final polishing process. It has been considered to perform polishing that also serves as the polishing. Specifically, for example, it is a different polishing means different from the finish polishing that can be continuously performed from the finish polishing of the mirror polishing, and removes foreign substances on the wafer surface without requiring a large amount of cleaning water as in the related art. There is a way to remove it.

As described above, in order to obtain a highly clean surface of the wafer substrate in the polishing cleaning following the final polishing, it is needless to say that foreign matter removed from the wafer surface by the polishing cleaning must be removed from the wafer surface. However, when a polishing cloth conventionally used for normal polishing is used for polishing and cleaning, not only does the foreign matter once removed be trapped on the cloth surface and is not discharged out of the wafer surface, but also the cloth itself is contaminated with organic substances and metal impurities. Since it can be a source of contamination, particles, etc., the desired high purification cannot be realized.

Therefore, a polishing pad dedicated to polishing and cleaning is used for the purpose of efficiently obtaining a high-purity surface of a wafer substrate in a step in which pre-cleaning is omitted by performing polishing and cleaning after finish polishing. Is desired.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a method for cleaning a wafer surface using a polishing pad capable of achieving high cleaning of a semiconductor wafer surface in a polishing and cleaning step. It is another object of the present invention to provide an apparatus for polishing and cleaning a wafer substrate using a polishing pad capable of achieving high cleaning of the surface of a semiconductor wafer in a polishing and cleaning step.

[0014]

In order to achieve the above object, a method for cleaning a surface of a wafer according to the first aspect of the present invention aims at removing foreign substances and the like on a surface of a wafer substrate and improving fine roughness. A method of cleaning the surface of a semiconductor wafer,
A water-polishing cleaning step of supplying only polishing water containing no abrasive to the surface of the wafer substrate to polish the polishing liquid, wherein the water-polishing cleaning step includes a flow of the cleaning water extending away from a center portion; A polishing pad having a path is used.

According to a second aspect of the present invention, in the method of cleaning a wafer surface, after lapping the surface of the wafer substrate cut out of the semiconductor single crystal, foreign matter on the mirror-polished surface of the wafer substrate is removed. A method of cleaning the surface of a wafer substrate for the purpose of removing or improving fine roughness, using a polishing agent on the mirror-polished surface of the wafer substrate by another polishing means different from the mirror polishing. A water polishing cleaning step of polishing by supplying only cleaning water without using the polishing pad, wherein the water polishing cleaning step extends away from the center using a polishing pad provided with a plurality of flow paths. It is.

According to a third aspect of the present invention, there is provided an apparatus for polishing and cleaning a semiconductor wafer, which planarizes or smoothes the surface of a wafer substrate and removes foreign substances and the like attached to the surface of the wafer substrate. There is provided a water-polishing cleaning means for supplying cleaning water containing no abrasive to the surface of the wafer substrate and polishing the polishing surface in a state where only the cleaning water is in contact with the polishing surface. The polishing pad includes a polishing pad provided with a flow path through which the cleaning water flows so as to extend away, and a turntable to which the polishing pad is attached.

Further, in the apparatus for polishing and cleaning a wafer according to the fourth aspect of the present invention, the surface of the wafer substrate cut out of the semiconductor single crystal is subjected to lapping, and then the surface of the wafer substrate is flattened or smoothed. A total polishing and cleaning device for a wafer substrate that removes foreign matter and the like attached to the surface of the wafer substrate, and a mirror polishing means for performing mirror polishing while supplying polishing water containing an abrasive to the surface of the wafer substrate,
This is another polishing means different from the mirror polishing means, and performs polishing and cleaning while supplying only cleaning water which does not contain an abrasive, which comprises only functional water in which the surface of the wafer substrate has been subjected to a predetermined process. Water polishing and cleaning means, wherein the water polishing and cleaning means has a polishing pad provided with a flow path for flowing the cleaning water extending away from the center, and a turntable to which the polishing pad is attached. It is.

According to the fifth aspect of the present invention, there is provided an apparatus for polishing and cleaning a wafer according to the third or fourth aspect.
In the apparatus for cleaning and polishing a wafer according to the above, the flow path is formed by a groove formed by cutting a surface of a polishing pad.

According to the present invention, the polishing pad used in the water polishing / cleaning step is provided with a flow path extending away from the center, and the cleaning water flows through the flow path. The foreign matter removed from the wafer surface can be discharged to the outside of the pad through the flow path together with the cleaning water.

Usually, the polishing pad is stuck on a turntable and is rotated at a high speed by the table (the center of rotation is generally coincident with the center of the pad surface). Water exerts an outward force due to centrifugal force. Therefore, in the present invention, the foreign matter is discharged out of the pad surface through the water channel while being urged by the centrifugal force together with the washing water entering the water channel without staying on the pad surface. At this time, contaminants, particles and the like generated from the pad (polishing cloth) itself are discharged to the outside through the water channel.

The water polishing and cleaning step of the present invention is used in various manufacturing processes of semiconductor wafers. For example, cleaning after mirror polishing in a process of processing a wafer substrate cut from a semiconductor single crystal, It is used for cleaning after polishing using a polishing agent, such as cleaning after CMP planarization polishing of a substrate with a pattern in a device process and cleaning after polishing of a silicon wafer with an oxide film in an SOI process.

The purpose of the water polishing and cleaning step is to remove foreign matter from the wafer surface to obtain a high cleanliness surface. However, in any case of the semiconductor wafer which has been subjected to various polishing steps in the semiconductor wafer manufacturing process, the present invention is applicable. According to the water polishing / cleaning step, the foreign matter once removed from the wafer surface is not trapped on the polishing cloth surface, does not contaminate the wafer substrate again, and is not contaminated by particles or the like originating from the polishing cloth. It is possible to avoid and obtain a wafer surface with high cleanliness.

In this water polishing cleaning, mechanical polishing is performed by using a polishing pad provided with the flow path while continuously supplying only cleaning water containing no abrasive. In this water polishing, polishing is performed only with cleaning water from the beginning by a dedicated polishing means, and it is not that the same polishing pad is used and the same polishing pad is switched to only cleaning water to wash away after using an abrasive.

Of the various processes described above, in the processing of a wafer substrate cut from a semiconductor single crystal, the surface of the wafer substrate after lapping is mirror-polished, The polishing pad provided with the flow path is used in the water polishing cleaning performed in step (1).
As a result, the foreign matter removed from the wafer surface in the water polishing and cleaning step is trapped on the pad surface and discharged to the outside through the flow path together with the cleaning water without stagnation.
After the completion of the water polishing cleaning, it is possible to proceed to the next final cleaning step with a good cleanliness surface of the wafer.

Further, the water polishing / cleaning means according to the present invention is provided in a polishing / cleaning apparatus for flattening or smoothing the surface of a semiconductor wafer and removing foreign substances and the like adhering to the wafer surface. There is a polishing pad provided with a plurality of flow paths through which the washing water flows away from the center and extends away from the center, and a turntable to which the polishing pad is attached, while rotating the polishing pad together with the table. By performing polishing and cleaning by bringing the wafer surface into contact with the pad, foreign matter removed from the wafer surface, particles generated from the polishing pad itself, and the like are discharged outward from the water channel together with the cleaning water.

Therefore, according to the polishing and cleaning apparatus of the present invention provided with the water polishing and cleaning means as described above, a wafer after a polishing step in various semiconductor wafer manufacturing processes, for example, a wafer substrate cut from a semiconductor single crystal Polishing agents used in various processes, such as those after mirror polishing in the processing process described above, those after CMP flattening polishing of patterned substrates in the device process, and those after polishing silicon wafers with oxide films in the SOI process. For each of the polished wafers, good water polishing and cleaning can be performed without fear of re-contamination by foreign substances removed from the wafer surface or particles from the polishing pad.

A total polishing and cleaning apparatus according to the present invention is used in a processing process of a wafer substrate cut out of a semiconductor single crystal among the above various processes, and is provided after a lapping process. Mirror polishing means for performing mirror polishing while supplying water containing an abrasive to the surface of a wafer substrate, and water for performing polishing and cleaning using an abrasive-free cleaning water consisting only of functional water on the wafer substrate surface after mirror polishing. The water polishing / cleaning means includes a polishing pad having a plurality of flow paths on its surface away from the center, and a turntable to which the polishing pad is attached.

The water polishing / cleaning means of the present invention is, for example, a mirror cloth used when the final polishing is performed after the final polishing, and the polishing cloth used in the final polishing is different from the polishing means. In this case, a polishing pad provided with the flow path dedicated to water polishing and cleaning is used.

As the flow path provided in the polishing pad for water polishing and cleaning of the present invention, the cleaning water supplied between the polishing pad surface and the surface to be polished of the wafer substrate can be discharged from the polishing pad surface thereafter. What is necessary is just a thing which is comprised from the groove | channel which notched the surface of the polishing pad as described in Claim 5, for example.

The more the number of channels is, the more the discharge efficiency of the washing water containing foreign matter is improved. However, when a plurality of channels are provided, it is preferable that the channels are uniformly dispersed. Examples of the form include various things such as a radial shape, a spiral shape, a parallel shape in a stripe, and a mesh shape in a plan view of the pad, and the flow in the flow path is polished. Any material that can be led to the outer periphery of the pad may be used.

However, the flow path of the present invention is not limited to the one formed on the surface of the polishing pad as described above.
The surface shape of the polishing pad, such as a hollow flow path that passes through the inside of the pad from the front side or a flow path formed by forming a groove on the back surface of the pad and a through hole reaching the back surface groove from the front side, In the case of the configuration in which only micropores can be seen, the influence on the flatness of the pad surface is relatively smaller than in the case of the groove formed on the surface.

Further, in the polishing pad of the present invention, since contaminants such as particles generated from the pad itself can be discharged to the outside, the same base material as a conventional polishing cloth which may generate such contaminants is used. Since it can be used for the polishing pad of the invention and does not necessarily require a special substrate, it is easy to manufacture.

The water-polishing cleaning of the present invention is a combination of quasi-chemical cleaning using only cleaning water containing no abrasive and the like and physical cleaning by water polishing, and has only a wiping function for removing slurry. Instead, it has a function of removing foreign substances such as particles, metal impurities, and organic substances. Therefore, a large amount of cleaning water is not required unlike the conventional pre-cleaning before the final cleaning.

It is preferable to use one or more functional waters as the washing water of the present invention. Functional water is mainly water that has been subjected to a specific treatment based on ultrapure water.Various water that has functions such as particle removal, metal impurity removal, organic matter removal, natural oxide film removal, and static electricity removal are available. You can choose. Specifically, for example, megasonic (hereinafter, referred to as MS) irradiated ultrapure water, ozone-added ultrapure water, electrolytic anode water, electrolytic cathode water, low dissolved oxygen water, electric resistance adjustment water,
MS irradiation + ozone water, MS irradiation + anode water, cathode water + ozone water, cathode water + low dissolved oxygen water, or a combination of these functional waters + electric resistance adjusting water.

The number of channels formed on the surface of the polishing pad for polishing and cleaning according to the present invention can be efficiently discharged as the number of channels and the arrangement thereof are more uniform. If it is too large, the pad surface will be uneven, which may adversely affect the wafer surface in the polishing and cleaning process. Therefore, it is preferable that the ratio of the total area (equivalent to the surface area) determined by the flow path width and the flow path width to the total surface area of the pad is appropriately set as the upper limit of the flow path formation conditions. For example, the width of the flow path is preferably 3.0 mm or less.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of the present invention, FIG. 1 shows an overall polishing / cleaning apparatus for performing a water polishing cleaning after a final polishing in a mirror polishing of a 400 mm large diameter wafer substrate. In the present embodiment, in the case of using a turntable provided with a polishing pad for polishing and cleaning (hereinafter referred to as a polishing cleaning pad) having radial grooves (flow paths) formed on the surface for water polishing and cleaning. Is shown.

As shown in the schematic plan view of FIG. 1 (a), in the present general polishing and cleaning apparatus 1, a lapping treatment is performed, and the wafer substrate 10 after the mirror polishing is mirror-finished. A polishing section 11 and a polishing / cleaning section 21 as a water polishing / cleaning means for polishing and cleaning the surface of the finished polished wafer substrate are provided adjacent to each other via a partition 7, and both are communicated only by the transport path 2 penetrating the partition 7. doing.

The transport path 2 is for transporting the wafer substrate 10 after the finish polishing to the polishing / cleaning unit 21 and includes, for example, a roller conveyor 3 as a transport mechanism. The atmosphere of the finish polishing section 11 and the polishing and cleaning section 21 are controlled by filling the transfer path 2 with running water or performing gas control such that gas flows unidirectionally from the polishing and cleaning section 21 to the finish polishing section 11. The atmosphere can be substantially isolated from each other, and each can be a closed system.

The polishing and cleaning unit 21 is required to maintain a high degree of cleanliness. However, if the atmosphere of the finish polishing unit 11 can be substantially shut off as described above, the atmosphere of the polishing and cleaning unit 21 is controlled by the atmosphere of the finish polishing unit 11. It is easy because it is not affected by

In the finish polishing section 11, a top ring head section 13 for holding the wafer substrate 10 with the front side of the wafer substrate 10 being the surface to be polished facing downward and holding the wafer substrate 10 by suction (by suction under reduced pressure) on the back side is provided. And it is provided so as to be movable in the vertical direction.

On the movement path of the head section 13 at the center, a finish polishing surface plate having the polishing cloth 12 adhered to the upper surface is rotatably installed. This polishing cloth 1
For 2, a suede-shaped material obtained by foaming polyurethane on a nonwoven fabric is used, for example, a material generally used for finish polishing in the past. Further, on the movement path of the head unit 13, an opening 4 into which the wafer substrate 10 after the finish polishing is put into the transfer path 2 is provided.

Further, a slurry nozzle (not shown) for supplying a slurry as an abrasive onto the polishing cloth 12 at the time of polishing, and a rinsing for supplying ultrapure water as rinsing water are provided in the finishing polishing section 11. Nozzles (not shown) are provided. As a result, polishing water containing an abrasive is supplied.

On the other hand, an opening 5 for picking up the wafer substrate 10 conveyed from the finish polishing unit 11 from the transfer path 2 is provided in the polishing and cleaning unit 21. A polishing and cleaning top ring head 23 for holding the back surface by suction is provided.

In the polishing / cleaning section 21, a polishing / cleaning platen having a polishing / cleaning pad 22 adhered to the upper surface thereof is rotatably provided at the center, and the wafer substrate 10 is finally cleaned after polishing and cleaning. A shooter 24 that feeds into a carrier cassette 25 for carrying the process is provided.

The polishing and cleaning top ring head 23
Is horizontally rotatable from the top of the opening 5 to the center of the polishing / cleaning platen (polishing / cleaning pad 22) to the upper end of the shooter 24. Further, the polishing and cleaning unit 21 includes an ultrapure water nozzle (not shown) for supplying ultrapure water onto the polishing and cleaning platen during polishing and a functional water nozzle (not shown) for supplying functional water. Have been. Here, functional water or ultrapure water is supplied as cleaning water containing no abrasive.

As shown also in the partial sectional view of FIG.
The polishing / cleaning pad 22 used in the present apparatus was formed from a circular polishing cloth made of polyurethane having a diameter of 900 mm as a base material, and 16 grooves having a width of about 2.0 mm and a depth of about 1.0 mm were formed radially from the center in the radial direction. Things.

The final polishing and water polishing and cleaning steps of the wafer substrate 10 in the present apparatus having the above-described configuration are as follows.
It is as follows. First, a carrier cassette 14 containing a plurality of roughly polished wafer substrates 10 that have not been subjected to an etching process after lapping is loaded into a predetermined location in the finish polishing section 11, and the finish polishing section 11 and the polishing and cleaning section are loaded. 21 are each in a sealed state. The inside is maintained in a nitrogen gas atmosphere.

First, in the finish polishing section 11, the wafer substrate 10 taken out of the carrier cassette 14 by the wafer loader is held by the top ring head section 13 for finish polishing by suction of the back surface thereof, and is placed on the polishing cloth 12 of the platen for finish polishing. Move horizontally until The surface plate for finish polishing is rotated at a predetermined speed, and a predetermined amount of slurry or rinsing water is supplied from each nozzle onto the polishing cloth 12, and the top ring head portion 13 is lowered in the vertical direction so that the wafer substrate Polishing is performed by bringing the surface (polished surface) 10 into contact with the upper surface of the rotating polishing cloth 12.

After the mirror polishing, the top ring head 1
3 and is horizontally moved onto the opening 4 of the transport path 2.
The suction holding by the top ring head 13 is released, and the polished wafer substrate 10 is dropped from the opening 4 into the transport path 2. In the finish polishing section 11, the above operation is repeated,
Polishing of all the wafer substrates 10 stored in the carrier cassette 14 is sequentially performed and the wafer substrates 10 are loaded into the transport path 2.

In the transport path 2, the loaded wafer substrate 10 is driven by the roller conveyor 3 so that
Is transported to the side. At this time, if the water flow is set to be opposite to the transport direction, a simple flushing effect on the surface of the wafer substrate 10 by the reverse water flow can be obtained, and the foreign matter removed from the surface can not adhere to the substrate surface again by the reverse water flow. Absent. The cleaning effect of the brush scrub on the wafer substrate 10 conveyed on the rollers may be further added by making the surface of each roller a brush.

Although the inside of the polishing and cleaning section 21 is maintained in a nitrogen gas atmosphere, the atmosphere is controlled to a high degree of cleanliness by driving an air conditioning system or the like. The wafer substrate 10 transported in the water in the transport path 2 to the opening 5 on the side of the polishing and cleaning unit 21 by the roller conveyor 3 is attracted to the top ring head 23 for polishing and cleaning by back surface adsorption without bringing in the atmosphere of the finish polishing unit 11. Will be retained.

The wafer substrate 10 is moved to a position above the polishing and cleaning pad 22 of the surface plate for water polishing and cleaning by rotating the top ring head 23 in the horizontal direction while at least the polished surface is wet. The surface plate for polishing and cleaning is rotated at a predetermined speed, and a predetermined amount of functional water is supplied from the nozzle to the upper surface of the polishing and cleaning pad 22, and the top ring head 23 is lowered to finish polishing the wafer substrate 10. Polishing and cleaning are performed by bringing the surface into contact with the upper surface of the polishing and cleaning pad 22. Here, so-called water polishing cleaning is performed by continuously supplying only cleaning water from the beginning to the end of polishing without using any abrasive or the like.

In this water polishing cleaning, the cleaning water supplied between the surface of the wafer substrate 10 and the surface of the polishing cleaning pad from above the polishing cleaning pad 22 is moved outwardly on the pad surface by centrifugal force due to the rotation of the platen. Moving. At this time, the groove S
The cleaning water flowing into the inside flows while being urged to the outer periphery along the groove S, and is discharged out of the pad surface. However, foreign matters and pads removed from the surface of the wafer substrate 10 are also removed together with the flow of the cleaning water. Is discharged. In addition, even if organic substances, particles, and the like are generated from the polishing cleaning pad 22 during polishing cleaning,
These are also discharged out of the pad through the groove S together with the cleaning water.

As described above, in the water polishing cleaning by the present apparatus, foreign matter and contaminants existing between the surface of the wafer substrate 10 and the surface of the polishing cleaning pad are efficiently discharged through the groove together with the flow of the cleaning water. Therefore, even with a large-diameter wafer substrate, the problem of foreign matter remaining between the surface of the wafer substrate 10 and the polishing cleaning pad surface and recontamination is eliminated, and a high-cleanness surface of the polished wafer surface is obtained after cleaning. Can be

After the water polishing and cleaning, the top ring head 2
3 is further rotated in the horizontal direction, the suction holding is released on the shooter 24, and the wafer substrate 10 is transferred to the shooter 24. The shooter 24 may be of any type, for example, using a tilt and a water flow, and can be any structure that can feed the wafer substrate 10 from one end to the carrier cassette 25 at the other end in a clean state.

The above steps are repeated, and the finish-polished wafer substrate 10 sent from the finish polishing section 11 through the transport path 2 is sequentially subjected to water polishing and cleaning. As aforementioned,
Wafer substrate 1 with high cleanliness surface after washing with water
0 can proceed to the final cleaning step.

In the above-described embodiment, the polishing and cleaning pad in which radial grooves are formed as the flow path is shown. However, the present invention is not limited to this. For example, as shown in FIG. (A) of the spiral shape,
Any flow path can be used, such as the stripe-shaped one or the mesh-shaped one in (b), as long as the flow of the cleaning water urged by the centrifugal force due to the rotation of the platen can be efficiently led to the outer periphery of the pad. Therefore, the flow path does not necessarily need to be a regular straight line or curve, that is, when the polishing surface of the polishing and cleaning pad in contact with the wafer substrate surface is viewed as a convex part surrounded by the flow path, the planar shape of the convex part is Various shapes can be arbitrarily selected, and a region around the convex portion forms a flow path.

The size of the polishing and cleaning pad, the width and the number of the flow paths, and the like are appropriately set according to various conditions such as the size of the wafer substrate to be subjected to polishing and cleaning and the design of the apparatus.

[0059]

As described above, in the present invention, in water polishing and cleaning after polishing using an abrasive, the use of a dedicated polishing and cleaning pad allows foreign substances and the like existing between the wafer surface and the polishing and cleaning pad surface to be eliminated. Since the water is efficiently discharged from the pad surface together with the cleaning water through the flow path in which the pad is formed, there is an effect that a high-cleanliness surface can be obtained even after polishing and cleaning of a large-diameter wafer substrate.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a general polishing and cleaning apparatus according to an embodiment of the present invention, in which (a) is a plan view showing a schematic configuration inside the apparatus, and (b) is a partial cross-sectional view of a polishing and cleaning section.

FIG. 2 is a schematic plan view showing an example of a polishing and cleaning pad having a flow path different from that of FIG. 1;

[Explanation of symbols]

 1: Comprehensive polishing / cleaning device 2: Transport path 3: Roller conveyor 4, 5: Opening 7: Partition wall 10: Wafer substrate 11: Finish polishing section 12: Polishing cloth 13: Top ring head section (for final polishing) 14: Carrier cassette 21: Polishing / cleaning unit 22: Polishing / cleaning pad S: Groove 23: (For polishing / cleaning) Top ring head unit 24: Shooter 25: Carrier cassette

Continued on the front page (72) Inventor Minami Minami 555 Nakanotani, Annaka-shi, Gunma 1 Inside Super Silicon Laboratories, Inc.

Claims (5)

[Claims] 1. A method of cleaning a surface of a semiconductor wafer for removing foreign matter and the like on a surface of a wafer substrate and improving a fine roughness, wherein only cleaning water containing no abrasive is applied to the surface of the wafer substrate. A water polishing cleaning step of supplying and polishing the wafer, wherein the water polishing cleaning step uses a polishing pad having a flow path through which the cleaning water extends so as to extend away from the center. Surface cleaning method. 2. The surface of a wafer substrate cut out of a semiconductor single crystal and subjected to a lapping process, and then the surface of the wafer substrate is removed for the purpose of removing foreign substances and the like and improving the fine roughness of the mirror-polished surface of the wafer substrate. A cleaning method, comprising: a water polishing cleaning step of supplying only cleaning water without using an abrasive to the mirror-polished surface of the wafer substrate by a different polishing means different from the mirror polishing to polish. The method for cleaning the surface of a wafer, wherein the water polishing and cleaning step uses a polishing pad provided with a flow path for flowing the cleaning water extending away from a central portion. 3. An integrated polishing and cleaning apparatus for a semiconductor wafer, which flattens or smoothes the surface of a wafer substrate and removes foreign substances and the like attached to the surface of the wafer substrate, wherein the surface of the wafer substrate does not contain an abrasive. A water-polishing cleaning means for supplying cleaning water and polishing in a state where only the cleaning water is in contact with the polishing surface, the water-polishing cleaning means including a flow path for flowing the cleaning water extending away from a central portion. An overall polishing and cleaning apparatus for a wafer substrate, comprising: a polishing pad; and a turntable to which the polishing pad is attached. 4. After polishing the surface of a wafer substrate cut from a semiconductor single crystal, flattening or smoothing the surface of the wafer substrate and comprehensively polishing and cleaning the wafer substrate to remove foreign substances and the like attached to the wafer substrate surface. An apparatus, comprising: mirror polishing means for mirror polishing while supplying polishing water containing an abrasive to the surface of the wafer substrate; polishing means different from the mirror polishing means, wherein the surface of the wafer substrate Water-polishing cleaning means for performing polishing and cleaning while supplying only cleaning water not containing an abrasive, which comprises only functional water subjected to a predetermined process, and wherein the water-polishing cleaning means moves away from a central portion. A polishing pad having a flow path through which the cleaning water flows, and a turntable to which the polishing pad is attached. Polishing and cleaning equipment. 5. The apparatus for cleaning a surface of a wafer according to claim 3, wherein the flow path is formed by a groove formed by cutting a surface of a polishing pad.