JP2001267276A - Cleaning method of work holder panel, and polishing apparatus and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work polishing apparatus wherein such foreign matters as an abrasive and abrasive residue do not remain on its work holder panel and the supporting member thereof, etc., when cleaning its work holder panel by its brushing material, and provide a cleaning method of its work holder panel, and further, provided a polishing method for polishing a work by using such a polishing apparatus. SOLUTION: A work polishing apparatus 1 has at least a work holder panel 2 for holding a work, an abrasive cloth 11 for polishing the work, and a cleaning mechanism for cleaning at least a work holding surface 2a of the work holder panel 2 by sliding a brushing material 5 relatively to the work holding surface 2a while feeding a cleaning liquid to the work holder panel 2. This polishing apparatus can be made capable of the removal of the brushing material from the work holder panel which is performed without stopping the relative operation of the brushing material to the work holding surface, a similar cleaning of a side surface 2b of the work holder panel which is to be performed preferably, continuous feeding of the cleaning liquid after the removal of the brushing material, continuous blowing or air on the work holder panel after the feeding of the cleaning liquid, and the removal of the cleaning liquid by rotating the work holder panel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a work holding plate, a polishing apparatus for a work, and a method for polishing a work. More particularly, the present invention relates to a polishing apparatus and a method for cleaning a work holding plate in which no foreign matter remains on the work holding plate.

[0002]

2. Description of the Related Art Conventionally, as a device for polishing a surface of a work such as a semiconductor wafer, for example, a work holding plate made of metal, ceramics, glass or the like attached to a rotary holder, and a rotating plate having a polishing cloth adhered thereto. A polishing apparatus provided with a free surface plate is known. Note that the number of work holding plates is not limited to one, and one having a plurality of holding plates is generally known.

As a method of polishing a work surface using such a polishing apparatus, a work is held on a holding surface of each work holding plate on a surface opposite to the side to be polished, and a polishing liquid is placed on a polishing cloth. In general, polishing is performed by moving the work relative to the polishing cloth while pressing the surface of the work to be polished against the polishing cloth while supplying the polishing liquid. For example, when polishing a semiconductor wafer, one or a plurality of works are usually attached to one holding plate via wax, or the above-mentioned polishing is performed by directly vacuum-sucking the work holding plate.

Conventionally, when a thin plate-shaped work is polished as described above, for example, for polishing the surface of a semiconductor wafer, if the work is carried out with foreign matter interposed between the work holding plate and the work, the foreign matter is interposed. In a place where the work is performed, the work is held in a locally curved state by the foreign matter, so that the processed work has a shallow concave portion (dimple) corresponding to the size of the foreign matter, thereby deteriorating the processing accuracy of the work. It is known to cause. For this reason, it is not only necessary to clean the work before processing, but also to sufficiently clean the work holding plate, especially the holding surface which is in contact with the work, as well as the support member such as a rotary holder, and to remove foreign substances from the surface as much as possible. is needed. For example, after polishing the work, the brush material is slid while supplying the cleaning liquid to the holding surface before holding the work to be polished next, and the polishing residue generated on the holding surface by the polishing agent or polishing, Alternatively, an operation of removing dirt such as foreign matter from the atmosphere in a processing chamber has conventionally been generally performed.

[0005]

However, with the miniaturization of circuits such as LSIs, the polishing of semiconductor wafers and the like, which require increasingly strict flatness, is more than ever before, with the work holding plate and its support. There is a demand for cleaning members. Therefore, when cleaning these work holding plates and the like, it is necessary to pay attention to the contamination of the holding plates and the like due to foreign substances such as abrasives and polishing debris attached thereto, and especially work which has not been a problem in the past. It has become necessary to pay attention to the method of releasing (releasing) the brush material from the holding surface.

In the conventional polishing apparatus, after the operation is temporarily stopped while the brush material remains in contact with the holding plate, the brush material comes off from the holding plate by, for example, moving the holding plate in the horizontal direction. ing. However, if the brush cleaning is performed in such a manner, when the brush material is detached from the holding surface, the foreign matter may not be sufficiently removed, and the holding surface on which the foreign matter such as an abrasive or polishing residue is adhered may be removed. The present inventors have found that when the brush material is slid to remove these foreign materials, the foreign materials adhered to the brush material partially adhere to the holding plate again when the brush material is detached. Was issued.

Accordingly, the present invention provides a work polishing apparatus and a work holding plate cleaning method in which foreign substances such as abrasives and polishing debris do not remain on the holding plate and its supporting members when the work holding plate is cleaned with a brush material. It is an object of the present invention to provide a method for polishing a work using such a polishing apparatus.

[0008]

When a workpiece is polished while being held by a work holding plate, the distance between the work and the holding surface is set to 0.1 mm.
If fine particles of 5 μm or more are attached, dimples are likely to occur. Therefore, if the work is polished using a work holding plate with a small amount of fine particles of 0.5 μm or more adhering to the work holding surface as described above, the work can be polished with a very high flatness. Because it can be held, the polished wafer has a very high flatness.

According to the present invention, at least the work holding plate for holding the work and the work are polished in order to make the holding plate with the adhesion of the fine particles as small as possible. A polishing cloth and a work polishing apparatus having a mechanism for cleaning by sliding a brush material at least relative to a work holding surface while supplying a cleaning liquid to the work holding plate; A polishing apparatus is provided in which the brush material can be detached from the holding plate without stopping relative operation.

The inventors of the present invention have found that when a brush is slid relative to a work holding surface while cleaning liquid is supplied to the work holding plate in the work polishing apparatus to wash the work holding surface, the brush material and the brush material are held. By allowing the brush material to detach from the holding surface before stopping relative movement with the board,
It has been found that foreign substances such as abrasives and polishing debris can be effectively removed from the holding surface. Therefore, if the work is held on the work holding plate that has been cleaned in this way, foreign matter interposed between the work and the holding plate is greatly reduced, and the work can be held with a very high flatness. As a result, the polished wafer can be significantly reduced in unevenness such as dents in flatness.

In this case, as described in claim 2, it is preferable that the cleaning liquid can be supplied to the work holding plate even after the brush material is detached from the work holding plate. That is, the brush material is separated from the holding plate without stopping the operation, and furthermore, the cleaning liquid is supplied to the holding plate, particularly the work holding surface, so that foreign matter remains on the holding surface immediately after the brush material is separated. However, these can also be reliably removed.

Further, the brush material is slid relatively to the side surface of the work holding plate and / or the supporting member to which the work holding plate is attached while supplying the cleaning liquid. It is preferable that the cleaning can be performed.

Usually, the work holding plate is disk-shaped and has a side surface in addition to the holding surface corresponding to the bottom surface, and the holding plate itself is attached to a support member such as a rotary holder for rotating the same during polishing. ing. Although the side surface of the holding plate and the support member do not come into contact with the work, foreign substances such as abrasives and polishing debris tend to adhere thereto. Therefore, if the brush material can be relatively slid and cleaned while supplying the cleaning liquid also to the side surface of the work holding plate and the supporting member as described above, the entire surface of the holding plate, and further the supporting member Foreign matter can be removed, and the work can be more reliably held without intervening foreign matter.

Further, when the side surface of the work holding plate and / or the supporting member is cleaned with a brush material, the side surface of the work holding plate and / or the supporting member may be cleaned.
Alternatively, it is preferable that the brush material can be detached from the side surface of the work holding plate and / or the support member without stopping the relative movement of the brush material with respect to the support member. further,
As described in claim 5, it is more preferable that the cleaning liquid can be supplied to the work holding plate and / or the support member even after the brush material is detached from the side surface of the work holding plate and / or the support member.

As described above, with respect to the brush material for cleaning the holding plate side surface and / or the support member, the relative operation between the brush material and the holding plate side surface or the support member is stopped in the same manner as the brush material for cleaning the holding surface. By removing the brush material without removing it, not only the holding surface but also the entire surface of the work holding plate and the foreign material can be surely removed from the support member. By supplying the cleaning liquid to the support member, even if foreign matter remains on the side of the holding plate or the support member immediately after the brush material is detached, the foreign matter is also washed away, and the entire surface of the work holding plate and the support member of the holding plate are further cleaned. It is possible to clean and more reliably prevent foreign matter from intervening between the work and the holding plate.

Further, the work polishing apparatus according to the present invention is characterized in that:
As described in claim 6, after the supply of the cleaning liquid to the work holding plate and / or the support member is stopped, the cleaning liquid attached to the work holding plate and / or the support member is removed. You can also. After cleaning with the brush material while supplying the cleaning liquid to the work holding plate and the support member, the work holding plate remains wet with the cleaning liquid. There may be cases where foreign matter such as sand or polishing residue is included.
Therefore, by configuring to remove the cleaning liquid adhering to the surface of the holding plate and the support member as described above, not only the cleaning liquid adhering to the holding surface of the holding plate, but also the side surface of the holding plate or the support member. Can be prevented from being caused by the washing liquid flowing down.

As a specific method for removing the cleaning liquid adhering to the holding plate or the supporting member, as described in claim 7, air is blown to the work holding plate or the supporting member. As described above, the cleaning liquid can be scattered by rotating the work holding plate and the support member. With such a method, the cleaning liquid adhering to the work holding plate and the supporting member can be quickly removed, so that the work holding plate can be cleaned in a short time, and as a result, the efficiency of the work polishing work is also improved. I do.

[0018] In the work polishing apparatus according to the present invention, the work holding plate may include:
It is also possible to provide a through-hole and / or a circuit for adsorbing and holding the work, and to allow the cleaning liquid to flow through the through-hole and / or the circuit. As described above, the cleaning liquid flows through the through-holes and the circuit of the work holding plate, so that it is possible to remove foreign substances such as abrasives and polishing debris taken into these through-holes and the circuit. In addition, the inside of the holding plate can be reliably cleaned. Therefore, there is no problem that foreign matter comes out of these through holes and the like.

The cleaning liquid used in the present invention is not particularly limited as long as it can remove foreign substances adhering to the holding plate. As described in claim 10, water can be used as the cleaning liquid. By cleaning the holding plate and the like by sliding the brush material against the surface to be cleaned while supplying water as the cleaning liquid, foreign substances can be easily removed, and the cleaning cost can be reduced. There is also the advantage that you can.

Further, the present invention also provides a method for cleaning a work holding board. That is, as described in claim 11, the work held by the work holding board is polished with a polishing cloth, and after removing the work from the work holding board, at least the brush material is supplied while supplying a cleaning liquid to the work holding board. A method of cleaning by sliding relative to a work holding surface, wherein the brush material is detached from the holding plate without stopping relative movement of the brush material with respect to the work holding surface. A method for cleaning a holding plate is provided. By cleaning the holding plate by such a method, it is possible to reliably remove foreign substances such as abrasives and polishing debris adhering to the holding plate surface.

Further, as in the case of the work polishing apparatus,
As described in claim 12, cleaning is performed by relatively sliding the brush material while supplying a cleaning liquid to the side surface of the work holding plate and / or the support member to which the work holding plate is attached. It is also preferable that, in this case, as described in claim 13, the brush material be moved to the side surface of the work holding plate without stopping the relative operation between the brush material and the side surface of the work holding plate or the support member. And / or preferably detached from the support member.

Further, as described in claim 14, it is preferable to supply the cleaning liquid to the work holding plate and / or the support member even after the brush material is detached from the work holding plate and / or the support member.

Further, after the supply of the cleaning liquid to the work holding plate and / or the support member is stopped, the cleaning liquid attached to the work holding plate and / or the support member is removed. As a specific removing method, as described in claim 16, after the supply of the cleaning liquid to the work holding plate and / or the support member is stopped, air is blown, or as described in claim 18, As described above, the cleaning liquid can be scattered and removed by rotating the work holding plate and the support member.
By quickly removing the cleaning liquid on the surface of the holding plate and further on the surface of the supporting member by such a method, it is possible to prevent not only the holding surface of the holding plate but also contamination that may be caused by the cleaning liquid flowing along the side surface or the supporting member. Can be. When the cleaning liquid is removed by blowing air as described above, the number of fine particles having a size of 0.3 μm or more contained in the air is 1000 / L (n.
p. t. (Standard state))

As the cleaning liquid used in the present invention, it is preferable that the cleaning liquid has a content of fine particles of 0.3 μm or more and 1,000 particles / L or less. As for the flow rate of the cleaning liquid, it is preferable that the cleaning liquid is supplied at a flow rate of 0.5 L / min or more.

Further, according to the present invention, there is provided a method of polishing a work using the polishing apparatus according to the present invention. As described above, in the polishing apparatus according to the present invention, the brush material can be detached from the holding plate without stopping the relative movement of the brush material with respect to the work holding surface, and therefore, is attached to the holding surface after cleaning. The amount of fine particles is very small. Therefore, the work can be polished with little intervening fine particles between the holding surface and the work, and the polished work has achieved extremely high flatness without flatness defects such as dimples. .

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments.

FIG. 1 is a schematic partial sectional view showing an example of a workpiece polishing apparatus according to the present invention. The illustrated polishing apparatus 1 includes a work holding plate 2 attached to a rotation holder 4 that can rotate at a desired rotation speed, a surface plate 3 for polishing the work, a holding surface 2a of the work holding plate 2, and a side surface of the holding plate. 2b and a brush member 5 that slides relatively to the rotary holder. The work holding plate 2 is provided with a plurality of through holes 6, and the through holes 6 are connected from a vacuum line 7 to a vacuum device (not shown) so that the vacuum device is operated to suck and hold the work on the work holding surface 2a. Has become.

FIG. 2 is a plan view showing an example of the holding surface 2a of the holding board 2, and the through hole 6 is formed in the holding surface 2a.
Is formed. A polishing cloth 11 is adhered to the upper surface of the platen 3, and the polishing cloth 11 is rotated together with the platen 3 at a predetermined rotation speed.

First, a method of polishing a work using the polishing apparatus 1 will be described. The work is rotated together with the work holding plate while being sucked and held by the holding plate 2, and simultaneously pressed against the polishing cloth 11 with a predetermined load. . At this time, the polishing agent is supplied between the work and the polishing cloth 11 to perform polishing.
After removing a desired amount of polishing allowance by polishing, the work is detached from the holding plate 2 and is temporarily stored in pure water or a liquid obtained by adding ozone, hydrogen peroxide, a surfactant, or the like to pure water.

Next, another work is held on the holding plate 2 and polished in the same manner as described above. However, the holding plate 2 often has foreign substances such as abrasives and polishing debris attached thereto. When the workpiece is held and polished with these foreign substances adhered to 2a, dimples (dents) and the like are locally generated on the polished workpiece (wafer) according to the size of the foreign substances as described above, and the entire surface of the wafer is polished. Therefore, the holding plate 2 is cleaned before holding the work.

In the polishing apparatus 1 shown in FIG. 1, a holding surface cleaning brush member 5a for cleaning the holding surface 2a of the holding plate 2 and a side cleaning brush member 5b for cleaning the side surface 2b of the holding plate 2 are provided.
Brush material 5 is provided, and each brush material 5a, 5b
Is provided with a nozzle 9 and a cleaning liquid supply line 10.
The washing liquid is supplied from the nozzle 9 through the nozzle.

Holding plate 2 from which polished work has been removed
Is moved to the position of the brush material 5 in the horizontal direction and the vertical direction, and the brush material 5 is slid while supplying the cleaning liquid from the nozzle 9 in a state where the brush materials 5a and 5b are in contact with the holding surface 2a and the side surface 2b. Then, cleaning is performed. At this time, in addition to cleaning by moving the brush material 5 itself, the holding plate 2
By rotating, the brush material 5 can be relatively slid with respect to the holding plate to perform cleaning. Alternatively, both the brush member and the holding plate can be operated to perform relative sliding. The brush members 5a and 5b may be independently slid separately. Further, it is preferable that the rotary holder (support member) 4 is also cleaned by the same method. In this case, a brush material for cleaning the support member is separately provided in addition to the brush material 5 shown in the drawing, or the brush member is independently operated. The brush member 5b to be used may also be used for cleaning the rotary holder 4 while also serving as a side surface of the holding plate.

In the present invention, the sliding of the brush material with respect to the holding plate means not only that the brush material itself moves, but also that the holding plate itself moves by rotation or the like, or that the brush material itself moves. And the surface of the holding plate (holding surface and side surface) slides relative to each other.

In the present invention, the operation of the brush member 5 is stopped after the brush member 5 is slid as described above to remove the abrasive or the polishing residue adhering to the surface of the work holding plate 2. The brush material 5 is detached from the holding plate 2 without any further operation. As a result, foreign matter remaining on the surface of the holding plate 2 is greatly reduced.

In the polishing apparatus 1 according to the present invention, it is preferable to wash the holding plate 2 as described above and supply the cleaning liquid to the holding plate 2 even after the brush material 5 is detached. In particular, by continuously supplying the cleaning liquid to the holding surface 2a, the brush material 5
Even if foreign matter remains immediately after the separation, the foreign matter can be reliably removed. Further, more preferably, by continuing to supply the cleaning liquid also to the side surface 2b of the holding plate, it is possible to surely remove foreign matters from the entire surface of the holding plate.

Further, in order to reliably remove foreign matter from the entire holding board, through holes 6 and / or
Alternatively, the cleaning liquid can flow through the circuit 8. When cleaning with the brush material 5, the cleaning liquid supplied from the nozzle 9 penetrates into the through-hole 6 and a part of the circuit 8, and can remove foreign matters adhering in the through-hole 6 and the circuit 8. For example, if the cleaning liquid can be supplied from above the through-hole 6 through the vacuum line 7, foreign substances can be more reliably removed from the through-hole 6 and the like.

As the cleaning liquid, foreign substances can be removed.
There is no particular limitation as long as it does not act on the material of the holding plate or the work, but water can be suitably used. The water used as the cleaning liquid is preferably as high in cleanliness as possible, particularly preferably as close to pure water. It should be noted that all conventionally used cleaning liquids such as those obtained by adding a surfactant and the like to pure water can be applied. The specific cleanliness of such a cleaning liquid is 0.3 μm
The content of the fine particles is preferably 1,000 particles / L or less, and particularly preferably 500 particles / L or less. Further, the cleaning liquid is preferably supplied at a flow rate of 0.5 L / min or more. If a cleaning liquid having a low content of fine particles is used and the flow rate of the cleaning liquid is set to a certain value or more, cleaning can be performed more effectively.

As described above, the brush member 5 slid relative to the surface to be cleaned such as the holding surface is detached from the holding plate 2 without stopping its relative operation. Can effectively remove foreign matter from the entire holding plate 2, but the holding surface is contaminated by a low-cleaning cleaning liquid containing foreign matter and the like flowing along the holding plate side surface 2 b or the rotary holder 4. To prevent this, wash thoroughly and minimize contamination.

As described above, after the cleaning liquid is supplied to the entire surface of the holding plate 2 or further to the rotary holder 4 to sufficiently clean it, the cleaning liquid adhering to the holding plate 2, the rotary holder 4 and the like is removed. When polishing the wafer by bonding the wafer to the holding plate with wax or the like, it is necessary to evaporate and dry at least the cleaning liquid on the holding surface.However, the removal of the cleaning liquid in the present invention means drying as described above. In addition, it has a broad meaning that the cleaning liquid is scattered and removed as described below.

As a specific method of removing the cleaning liquid, the cleaning liquid can be scattered by blowing air onto the surface of the holding plate 2 or the like. The air to be blown at this time does not contain dust and mist, and is preferably as clean as possible. For example, air from which dust and oil have been removed through a filter or the like may be blown. Specifically, the number of particles of 0.3 μm or more contained in the blowing air is 100
If it is set to 0 / L (npt) or less, the fine particles remaining on the surface of the holding plate after the removal of the cleaning liquid can be reduced to a level not to impair the flatness of the polished wafer. Although it is advantageous to use air from the viewpoint of cost, other gases such as nitrogen can be used besides air. In addition, in order to speed up the removal of the cleaning solution, the air is removed by blowing hot air. You can also.

In addition, it is effective that the cleaning liquid is scattered by rotating the holding plate 2 by the rotary holder 4 at the time of removal. At this time, the higher the rotation speed, the more effective in a short time. In addition, if the cleaning liquid is removed by rotating the holding plate 2 and the like in this manner, there is no need to provide an auxiliary means for removing the cleaning liquid, which is advantageous in terms of cost. The cleaning liquid can be effectively removed by combining the method of blowing air and the method of rotating the holding plate 2.

When the work holding plate 2 is washed or dried (cleaning liquid is removed), the cleaning liquid and liquid droplets are placed around the brush material 5 (for example, at the position indicated by a dotted line in FIG. 1) in order to prevent scattering of the cleaning liquid and droplets outside the polishing apparatus. It is also possible to provide scattering prevention means. Specifically, a resin cover that covers the bottom (lower portion) and side portions of the brush material 5 may be provided integrally or independently of the brush material 5, and a hole for discharging the cleaning liquid may be opened at the bottom of the cover. . The material of the cover is preferably a transparent resin so that the state inside the cover can be observed, and an acrylic resin,
It is preferable to use a vinyl chloride resin or a PET (polyethylene terephthalate) resin. The side surface of the cover is entirely covered with the brush material 5 so that the droplets do not scatter outside when the holding plate 2 is washed and dried, and at least half of the height of the work holding plate 2 is covered during washing and drying. Preferably, the height is such that

Since the holding surface of the holding plate cleaned as described above is in a state where almost no fine particles such as polishing debris which cause the formation of dimples adhere when polished, the work is held on the holding surface. If polishing is performed, it is possible to obtain a workpiece having no dimples or the like and having extremely high flatness.

[0044]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. (Example 1) After performing polishing using a polishing apparatus 1 as shown in FIG. 1 provided with a holding plate 2 capable of holding a 200 mm diameter silicon wafer by vacuum suction, the wafer is removed from the holding plate 2. To a storage tank. Next, while supplying pure water to the holding plate 2 moved horizontally, the brush material 5 is supplied.
Was slid to wash the holding plate 2, and the brush member 5 was detached from the holding plate 2 while operating without stopping.

After the brush cleaning is performed in this manner, the holding plate 2 is raised, and 5 liters / minute of pure water is used for holding the work by vacuum suction in addition to the holding surface 2a and the side surface 2b of the holding plate 2. Washing was also performed for 15 seconds by flowing through the through holes 6. Thereafter, the holding plate is further horizontally moved to 200 rpm for 30 seconds.
m, and after the pure water adhering to the holding plate 2 was scattered by centrifugal force, the washing of the holding plate 2 was terminated.

(Comparative Example 1) After the wafer was polished in the same manner using the same polishing apparatus as in Example 1, the brush material was slid and held while supplying pure water to the horizontally moved holding plate. The board was washed, and sliding of the brush material was stopped while the brush material was still in contact with the holding board, and the supply of pure water was stopped at the same time. Next, the holding plate was moved horizontally to release the brush material from the holding plate, and the cleaning of the holding plate was completed.

The cleaning conditions and the like in Example 1 and Comparative Example 1 are as follows. Common Conditions of Example 1 and Comparative Example 1 Work holding board: made of SiC ceramics, rotation speed 50 rpm (at the time of polishing) Brush material: nylon flocking brush Brush cleaning time: 30 seconds and 180 seconds Cleaning liquid: pure water, supply amount 2 Liter / min (at the time of brush cleaning) 5 liter / min (after brush cleaning) Nozzle diameter: 1 mm φ Supply pressure: 1 kgG / cm ²

<Evaluation of Cleaning> A 200 mm (8 inch) diameter silicon wafer before mirror processing was brought into contact with the holding surface of each holding plate cleaned by the method of Example 1 and Comparative Example 1, and remained on the holding surface. The transferred foreign matter was transferred to the wafer and dried. Further, a specular wafer whose surface cleanliness is known in advance by a particle counter (the number of particles having a particle size of 0.5 μm or more is almost 0) is prepared, and the foreign matter is brought into contact with the wafer to which the foreign matter has been transferred. Transcribed. The foreign matter adhering to the surface of the mirror wafer to which the foreign matter was transferred in this way was again evaluated by a particle counter to create a map, and the map was shown in FIG. Note that the black dots indicate dirt due to foreign matter.

FIG. 3A shows a map of foreign matter on a mirror-finished wafer to which residual foreign matter on a work holding surface has been transferred after cleaning according to the present invention (Example 1), and FIG. 3B shows a conventional method. 5 shows a map of foreign matter on a mirror-finished wafer to which residual foreign matter on a work holding surface has been transferred after cleaning according to (Comparative Example 1). From these maps, the cleanliness of each work holding surface was compared. The particle counter used was a laser surface inspection device LS-6000 manufactured by Hitachi Electronics Engineering Co., Ltd. The number of particles (0.5 μm or more in diameter) on the mirror-finished wafer to which the residual foreign matter on the work holding surface cleaned in accordance with Example 1 was transferred was about 3
The number was 000 pieces / sheet (about 10 pieces / cm ² ).

Comparing FIG. 3A and FIG. 3B, the map of FIG. 3A according to the present invention shows that the number of foreign matters is small as a whole and no characteristic pattern is recognized. On the other hand, in the map shown in FIG. 3B, many foreign substances are observed on the whole, and the distribution is characterized by a characteristic striped pattern considered to be caused by the horizontal movement of the holding plate with the brush in contact at the end of cleaning. Was observed.

(Example 2 and Comparative Example 2) The holding plate was washed under the same washing method and washing conditions as those of the present invention (Example 1) or the conventional method (Comparative Example 1). The silicon wafer was held on a holding board and polished 200 pieces each, and the presence or absence of dimples on the surface of the polished wafer was measured by a magic mirror topograph. Among the measured polishing wafers, the diameter is 1m
A wafer having at least one dimple having a depth of 0.1 μm or more over m was determined as a defective product, and the ratio of the defective wafer to the polished wafer (hereinafter referred to as a dimple defect rate) was examined. The measurement results are shown in FIG. 4 for each of the conventional cleaning method and the cleaning method of the present invention, separately for the cleaning time.

As is clear from the graph of FIG. 4, the dimple defect rate shows a high value of nearly 20% in any of the cleaning times when the cleaning is performed by the conventional method. Was reduced to 2% in any of the washing times.

The present invention is not limited to the above embodiment. The above embodiment is an exemplification, and has substantially the same configuration as the technical idea described in the scope of the claims of the present invention. It is included in the technical scope of the invention.

For example, in the above-described embodiment, the description has been given of the polishing apparatus in which the cleaning liquid is supplied from the nozzle provided on the brush material. However, as long as the cleaning liquid can be supplied to the surface of the holding plate or the supporting member, the supply method is particularly preferable. Without being limited, the cleaning liquid can be supplied by a nozzle provided separately from the brush material. As for the brush material, a cleaning device having a brush material and a nozzle for supplying a cleaning liquid may be separately and separately provided from a polishing device having a surface plate and a holding plate.

Although the above embodiment is directed to a semiconductor wafer, the work polishing apparatus and the work holding plate cleaning method of the present invention can be applied without being limited to this, and a rotating polishing cloth can be used. Glass substrate to be polished,
The present invention can be applied to any polishing of workpieces such as quartz substrates, oxide single crystals, and magnetic disks.

[0056]

As described above, by cleaning the holding plate according to the present invention, it is possible to greatly reduce the amount of abrasives, polishing residues, and the like remaining on the holding plate. By holding the work using the work holding plate thus cleaned, there is almost no foreign matter between the work and the holding plate, and a work such as a semiconductor wafer that requires extremely high flatness is polished. Even when processing, the workpiece can be held while maintaining a very high flatness. The work thus held is polished, so that the unevenness of the flatness in the shape of a dent can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic partial sectional view showing an example of a workpiece polishing apparatus according to the present invention.

FIG. 2 is a plan view showing an example of a holding surface of a work holding board according to the present invention.

FIG. 3 is a map in which residual foreign matters on a holding plate cleaned in Example 1 and Comparative Example 1 are transferred to a wafer. (A) Map of Example 1 (B) Map of Comparative Example 1

FIG. 4 is a graph showing a dimple defect rate of wafers polished in Example 2 and Comparative Example 2.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Polishing device, 2 ... Work holding plate, 2a ... Work holding surface, 2b ... Work holding plate side surface, 3 ... Rotary surface plate, 4
... Rotating holder (support member), 5 ... Brush material, 5a ... Holding surface cleaning brush material, 5b ... Side cleaning brush material, 6 ... Through hole, 7 ... Vacuum line, 8 ... Circuit, 9 ... Nozzle,
10: cleaning liquid supply line, 11: polishing cloth.

 ──────────────────────────────────────────────────の Continuing from the front page (71) Applicant 390004581 Sanmasumi Semiconductor Industry Co., Ltd. (72) Inventor: Hisashi Masumura 150 Odakura Odaikura, Nishigo-mura, Nishishirakawa-gun, Fukushima Prefecture Shin-Etsu Semiconductor Co., Ltd. Semiconductor Shirakawa Laboratory

Claims (21)

[Claims] At least a work holding plate for holding a work, a polishing cloth for polishing the work, and a brush material being slid relative to at least a work holding surface while supplying a cleaning liquid to the work holding plate. A polishing machine provided with a mechanism for cleaning the workpiece, wherein the brush can be detached from the holding plate without stopping the relative movement of the brush to the workpiece holding surface. 2. The polishing apparatus according to claim 1, wherein the cleaning liquid can be supplied to the work holding plate even after the brush material is detached from the work holding plate. 3. The cleaning device according to claim 1, wherein a brush material is relatively slid while supplying a cleaning liquid to a side surface of the work holding plate and / or a support member to which the work holding plate is attached. The polishing apparatus according to claim 1 or 2. 4. The brush material can be detached from the side surface and / or the support member of the work holding plate without stopping the relative movement of the brush material with respect to the side surface and / or the support member of the work holding plate. The polishing apparatus according to claim 3. 5. The cleaning liquid can be supplied to the work holding plate and / or the support member even after the brush material is detached from the side surface and / or the support member of the work holding plate. A polishing apparatus according to claim 1. 6. After the supply of the cleaning liquid to the work holding plate and / or the support member is stopped, the work holding plate and / or
The polishing apparatus according to any one of claims 1 to 5, wherein a cleaning liquid attached to the support member is removed. 7. The polishing apparatus according to claim 6, wherein the removal of the cleaning liquid is performed by blowing air to a work holding plate and / or a support member. 8. The polishing apparatus according to claim 6, wherein the removal of the cleaning liquid involves an operation of scattering the cleaning liquid by rotating a work holding plate and a support member. 9. The apparatus according to claim 1, wherein the work holding board has a through hole and / or a circuit for sucking and holding the work, and a cleaning liquid can be flowed through the through hole and / or the circuit. Item 10. The polishing apparatus according to any one of Items 8 to 9. 10. The polishing apparatus according to claim 1, wherein the cleaning liquid is water. 11. A work held by a work holding plate is polished by a polishing cloth, and after removing the work from the work holding plate, a brush material is applied to at least the work holding surface while supplying a cleaning liquid to the work holding plate. A method for cleaning a work holding plate, wherein the brush member is detached from the holding plate without stopping the relative movement of the brush member with respect to the work holding surface. 12. A brush member is relatively slid while supplying a cleaning liquid to a side surface of the work holding plate and / or a support member to which the work holding plate is attached, to perform cleaning. A method for cleaning a work holding board according to claim 11. 13. The brush member is detached from the side surface and / or the support member of the work holding plate without stopping the relative movement of the brush member with respect to the side surface and / or the support member of the work holding plate. Claim 11
13. The method for cleaning a work holding board according to claim 12. 14. The work holding plate and / or the brush member is detached from the work holding plate and / or the support member.
14. The method for cleaning a work holding board according to claim 11, wherein a cleaning liquid is supplied to the support member. 15. The cleaning liquid attached to the work holding plate and / or the supporting member is removed after the supply of the cleaning liquid to the work holding plate and / or the supporting member is stopped. Item 15. The method for cleaning a work holding board according to any one of Items 14. 16. The method for cleaning a work holding plate according to claim 15, wherein the cleaning liquid is removed by blowing air to the work holding plate and / or the support member. 17. The air blown to the work holding plate and / or the support member contains 0.3 μm contained in the air.
17. The method for cleaning a work holding board according to claim 16, wherein the number of the fine particles is 1000 / L (npt) or less. 18. The method according to claim 15, wherein the removal of the cleaning liquid involves an operation of scattering the cleaning liquid by rotating a work holding plate and a supporting member. How to clean the work holding board. 19. The cleaning solution according to claim 1, wherein said cleaning solution contains 0.1.
The method for cleaning a work holding board according to any one of claims 11 to 18, wherein the content of the fine particles having a size of 3 µm or more is 1000 / L or less. 20. The method for cleaning a work holding plate according to claim 11, wherein the cleaning liquid is supplied at a flow rate of 0.5 L / min or more. 21. A method for polishing a workpiece using the polishing apparatus according to claim 1. Description: