JP2003103457A - Work holding board for polishing and polishing device and polishing method for work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing device and a polishing method for a work, particularly a polishing work holding board for polishing so that there are no irregular parts of a nanotopography level. SOLUTION: The work holding board for polishing is provided with a work holding board body having a plurality of through holes holding the work by vacuum suction and a holding face of the holding board body is covered by resin. A coefficient of thermal expansion of the resin covering the holding face is <=3×10<-5> /K. The polishing device for the work is provided with the work holding board for polishing. In the polishing method for the work, the resin with the coefficient of thermal expansion of <=3×10<-5> /K covers the holding face of the work holding board for polishing holding the work by vacuum suction, a rear face of the work is held by vacuum suction by the holding face, the work is contacted to abrasive cloth, and a surface of the work is polished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing device and a polishing method for a work, and more particularly to a work holding plate for holding a work.

[0002]

2. Description of the Related Art Conventionally, a method of manufacturing a work such as a silicon wafer used as a semiconductor substrate material is generally performed by using a Czochralski (CZ) method or a floating zone (FZ) method. A crystal growth step of manufacturing a crystal ingot and a wafer processing step of slicing the single crystal ingot and processing at least one main surface into a mirror surface are performed. To show the wafer processing step in more detail, the wafer processing step is a slicing step of slicing the single crystal ingot to obtain a thin disk-shaped wafer, and the cracking of the wafer obtained by the slicing step, in order to prevent chipping. A chamfering step for chamfering the outer peripheral portion,
A lapping process for flattening this wafer, an etching process for removing chamfering and processing strain remaining on the lapping wafer, a polishing (polishing) process for mirror-finishing the surface of the wafer, and a cleaning of the polished wafer , And has a cleaning step for removing the abrasive and the foreign matter adhering thereto. The above-mentioned wafer processing step shows the main steps, and other steps such as a heat treatment step may be added, the same step may be performed in multiple stages, or the order of steps may be changed.

Of these processes, polishing (polishing)
In the process, a wax mount batch type single-side polishing machine is currently mainstream in which a plurality of wafers are attached to a plate such as glass or ceramic with wax to polish one side. In this device, the plate holding the wafer is
Place on a surface plate with a polishing pad attached, apply a load to the upper top ring, and perform polishing while rotating the surface plate and top ring. In addition to this, there are various types of polishing devices. For example, a double-sided polishing method in which a wafer is sandwiched between upper and lower surface plates so that both surfaces are mirror-finished at the same time, a single-wafer method in which wafers are vacuum-adsorbed and held on a plate one by one, and the wafer is not used with an adhesive such as wax There are various methods such as a wax-free polishing method in which a backing pad and a template hold and polish.

In particular, in recent years, a wafer-by-wafer method has been adopted in which wafers are vacuum-sucked and held on a wafer holding plate (plate) one by one as the diameter of the wafer (work) increases. For example, an example of such a polishing apparatus will be described.
FIG. 1 is an explanatory diagram for explaining the outline of the configuration of a polishing apparatus equipped with a single-wafer polishing head that holds a wafer by a vacuum suction method.

The polishing device 20 is configured as a device for polishing one surface of a work W, for example, a semiconductor silicon wafer, and includes a rotating work table 21, a polishing work holding board 1 mounted on a polishing head 10, a nozzle (a polishing agent supply). Tube) 23. A polishing cloth (polishing pad) is provided on the upper surface of the platen 21.
22 is attached. The surface plate 21 is rotated at a predetermined rotation speed by a rotation shaft.

The work holding plate 1 holds a work (wafer) W on its work holding surface 8 by vacuum suction or the like, is mounted on a polishing head 10 having a rotating shaft, and is rotated by the polishing head 10 at the same time. Polishing cloth 2 with a predetermined load
Press work W against 2. The polishing agent 24 is supplied from the nozzle 23 onto the polishing cloth 22 at a predetermined flow rate, and the polishing agent 24 is supplied between the work W and the polishing cloth 22 to polish the work W.

Further, the work holding plate 1 comprises a work holding surface 8 and a work holding plate body 2 having a large number of through holes 4 for vacuum suction and a work holding plate back plate 5, and the through holes 4 hold the work. The space between the board body 2 and the back plate 5 (vacuum part) 6 leads from the suction path 7 to the vacuum device,
The work W is sucked and held on the work holding surface 8 by the generation of vacuum. This suction holding mechanism is also used when the wafer is transported.

The work holding surface 8 of the work holding plate body 2 is
It is covered with a resin layer 3 having a through hole 4. This is because when a work is directly held on the surface of the work holding plate main body 2 such as metal or ceramics, scratches or stains are generated on the back surface of the work, and the surface of the work holding plate main body 2 is tens of μm in order to prevent it. Ultra-thin Teflon (registered trademark) of a few millimeters, materials known by trademarks such as nylon, resin coatings such as vinyl chloride, and acrylic resin plates with holes for vacuum suction are held on the work holding board. A work holding plate or the like, which is adhered to the surface of the main body 2 and whose surface is polished, is used. In particular, an epoxy resin, which is a thermosetting resin, is particularly useful in terms of easiness of coating, hardness and mechanical strength which are physical properties of the film after thermosetting, and quality such as linear expansion coefficient.

Further, in the case of polishing, since a soft polishing cloth is used, even if the surface of the work holding plate is made flat, the surface of the polishing cloth gradually changes due to creep deformation of the polishing cloth, etc. There is a problem that the work after polishing is not always flat. Therefore, as described above, a thin resin is coated on the surface of the work holding plate, and a holding plate is produced in accordance with the creep deformation of the polishing cloth by polishing the surface of the work holding plate coated with this resin, and thereafter. A method of holding a work on the holding plate and polishing the work is also used.

The polishing head 10 is provided with a pressure space 13 inside the rotary holder 11 and holds the polishing work holding plate 1 in an airtight manner via an elastic sheet 12. The pressurized space 13 is connected to the air compressor via a pressurized air supply passage 14. Then, the polishing head 10 applies rotation or swing to the work holding plate that holds the work W on the surface of the work holding surface 8 made of the resin layer 3 by vacuum suction, and at the same time pressurizes the back surface of the work holding plate 1 with air. The work holding plate 1 is pressed against the polishing cloth 22.

[0011]

When polishing is performed by the above-mentioned single-wafer type apparatus for holding by vacuum suction and polishing, slight irregularities may be observed on the surface of the wafer. Especially, many were observed around the adsorption holes. This is the level of unevenness that is observed when observing with a magic mirror image or when evaluating unevenness in a minute area called nanotopography.

Nanotopography (also called nanotopology) is unevenness having a wavelength of about 0.1 mm to 20 mm and an amplitude of about several nm to 100 nm.
As an evaluation method, in the area of a square block having a side of about 0.1 mm to 10 mm or a circular block having a diameter of about 0.1 mm to 10 mm (this range is called WINDOW SIZE etc.) Height difference (PV value;
Evaluate peak to valley). This PV value is Nanotopograp
Also called hy height. For nanotopography, it is particularly desired that the maximum value of the unevenness present in the evaluated wafer surface is small.

When metal wiring is formed on a wafer in a device manufacturing process, an insulating film is formed on the metal wiring, and the insulating film is polished, the presence of the unevenness at the above level becomes a problem. It's starting. In particular, in the high-integrated device process, it may cause focus failure in lithography exposure, leading to a decrease in the yield of high-integrated devices,
It was a problem.

The present invention has been made in view of the above circumstances, and provides a polishing apparatus and a polishing method for polishing such that the above-mentioned level of unevenness does not occur, particularly a polishing work holding plate. With the goal.

[0015]

The present invention for solving the above-mentioned problems comprises a work holding plate body having a large number of through-holes for holding a work by vacuum suction, and the holding surface of the holding plate body is made of resin. In the coated polishing work holding plate, the coefficient of thermal expansion of the resin coating the holding surface is 3 × 10 ⁻⁵ /
It is a polishing work holding plate characterized by being K or less (claim 1).

Such a coefficient of thermal expansion is 3 × 10 ^-5 / K
The polishing work holding plate having the following low thermal expansion resin coated on the holding surface has a remarkably small amount of thermal deformation of the holding surface during polishing, so that a wafer with improved nanotopography can be manufactured. . That is, the coefficient of thermal expansion is 3 ×
If it is 10 ⁻⁵ / K or less, the shape change of the adsorption holes that affects the unevenness of the nanotopography hardly occurs.
Further, the coefficient of thermal expansion is smaller than 3 × 10 ⁻⁵ / K, and it is preferable that the coefficient of thermal expansion is as similar as possible to the main body of the work holding plate.

In this case, it is preferable that the resin coating the holding surface has a thermal conductivity of 0.4 W / mK or more (claim 2). When the thermal conductivity of the resin coated on the holding surface for holding the work is 0.4 W / mK or more, the heat generated during polishing becomes uniform in the resin and can be effectively radiated. It is possible to more effectively prevent deterioration of nanotopography due to thermal deformation. Therefore, the upper limit of the thermal conductivity is not particularly limited. The upper limit is determined by the material of the resin, the additive to be added to it, the amount added (the amount that can be added), etc., but the higher the thermal conductivity, the more difficult the temperature difference between the front and back of the resin coating layer is Thermal deformation is suppressed, which is preferable. 0.4
If it is W / mK or more, the shape change of the adsorption holes that affects the unevenness of the nanotopography hardly occurs. In addition,
The thermal conductivity of the resin referred to in the present invention is a value evaluated by a method according to JIS R1611.

In this case, the resin coating the holding surface is
It is preferably an epoxy resin filled with silica (claim 3). When the resin coating the holding surface is an epoxy resin filled with silica as a heat conduction adjusting agent, the coefficient of thermal expansion of the holding surface is reduced and the thermal conductivity is increased, which is preferable. In particular, silica can be filled in a larger amount than calcium carbonate (the filling amount is limited to about 50% by weight), which has been conventionally filled in the epoxy resin coating the holding surface, and the coefficient of thermal expansion is very small. This is preferable because the thermal expansion coefficient of the holding surface can be further reduced.

In this case, the silica filled in the epoxy resin is preferably 60% by weight or more of the epoxy resin (claim 4). When the silica filled in the epoxy resin is 60% by weight or more of the epoxy resin, the coefficient of thermal expansion is sufficiently small and the thermal conductivity is increased, so that the coefficient of thermal expansion of the resin is 3 × 10 ^{−. 5} / K or less,
The thermal conductivity is preferably 0.4 W / mK or more, which is preferable.

In this case, the silica filled in the epoxy resin is preferably in the form of particles having a particle size of 1 to 10 μm (claim 5). In the case of small silica particles of less than 1 μm, the viscosity of the filled resin increases, and the resin is not filled with too much silica. Further, in the case of large silica particles having a size of more than 10 μm, the surface roughness of the coated resin becomes large, and holding the wafer on the surface may deteriorate the nanotopology. Therefore, the silica particles to be filled preferably have a particle size of about 1 to 10 μm. Furthermore, when large silica particles having a shape close to a sphere having a size of about 10 μm and small particles having a shape close to a sphere having a size of about 1 to 3 μm are packed, it is possible to further increase the packing amount, thereby reducing the coefficient of thermal expansion and reducing the thermal expansion coefficient. The conductivity can be made higher.

Further, according to the present invention, there is provided a polishing apparatus for a work, comprising a polishing work holding plate (claim 6), wherein the resin layer on the surface of the polishing work holding plate is less likely to be thermally deformed. The graph can be improved. In particular, when a silicon wafer is polished as a work, it is possible to reduce focus defects in lithography exposure in the highly integrated device process, and it is possible to improve the yield of highly integrated devices.

According to the present invention, the coefficient of thermal expansion is 3 × 10 on the holding surface of the polishing work holding plate which holds the work by vacuum suction.
^A method for polishing a work, which comprises coating a resin of ^-5 / K or less, vacuum holding the back surface of the work by the holding surface, and then bringing the work into contact with a polishing cloth to polish the surface of the work. There is (claim 7).

As described above, by coating the holding surface of the polishing work holding plate with a resin having a thermal expansion coefficient of 3 × 10 ⁻⁵ / K or less, the amount of thermal deformation can be reduced.
Improved polishing of nanotopography is possible.

In this case, it is preferable that the resin coating the holding surface has a thermal conductivity of 0.4 W / mK or more (claim 8). When the thermal conductivity of the resin coating the holding surface is 0.4 W / mK or more, the heat generated during polishing can be made uniform in the resin and the heat can be efficiently conducted and radiated. Therefore, abnormalities due to thermal deformation can be further prevented, and a wafer with improved nanotopography can be manufactured.

Further, in this case, before the back surface of the work is vacuum-sucked and held, the holding surface of the polishing work holding plate coated with the resin is brought into contact with the polishing cloth to polish the work, and then the work is held by the holding surface. It is preferable to hold the back surface of the workpiece by vacuum suction and then bring the workpiece into contact with the polishing cloth to polish the surface of the workpiece (claim 9).

As described above, before the back surface of the work is vacuum-sucked and held, the holding surface of the polishing work holding plate covered with the resin is brought into contact with the polishing cloth to polish the shape of the holding surface. By following the shape, it is possible to correct the deviation of the flatness of the work due to the influence of the deformation of the polishing cloth during polishing, which is particularly effective for improving the flatness of a thin work such as a wafer.

The present invention will be described in more detail below.
The present invention is not limited to these. The present inventor has conducted an intensive investigation on the cause of deterioration of nanotopography in the polishing process of the work, and the cause is that heat is accumulated in the resin coating the work holding surface and the holding surface is deformed. It became clear. Then, it was found that this phenomenon was remarkable especially near the adsorption holes.

For example, in the polishing work holding plate as shown in FIG. 2A, the temperature T1 of the surface of the resin layer 3 made of epoxy resin for holding the wafer and S
It has been revealed that a difference occurs in the temperature T2 on the side in contact with the work holding plate body 2 made of ceramics such as iC, and the epoxy resin of the resin layer 3 is deformed. It was also found that this deformation affected the nanotopography-level irregularities.

For example, as shown in FIG. 2B, T1>
At T2, when the wafer is vacuum-sucked and held, the vicinity of the suction hole becomes dented. As shown in FIG. 2C, when T1 <T2, the vicinity of the suction hole is held when the wafer is vacuum-sucked and held. It will become a raised shape. Therefore, when the wafer sucked and held in this state is polished, in the case of T1> T2, the vicinity of the suction hole of the wafer becomes
Since it was held in a depressed state, the polishing amount became insufficient, and the polishing amount rose after the polishing (FIG. 2B). Conversely, T
When 1 <T2, since the vicinity of the suction hole of the wafer was held in a raised state, the polishing amount was large and the wafer had a recessed shape (FIG. 2C). Due to such deformation of the resin layer, it is considered that waviness occurs near the adsorption holes and nanotopography deteriorates.

In order not to deteriorate such nanotopography, it is necessary to prevent thermal deformation of the resin coating the work holding surface. For that purpose, it is necessary to pay attention to the thermal expansion coefficient and the thermal conductivity among the thermal characteristics of the resin. This is because if the coefficient of thermal expansion is small, thermal deformation does not easily occur even if there is a large temperature difference between the front and back surfaces of the resin layer, and if the thermal conductivity is large, the heat generated during polishing tends to be uniform within the resin. In addition, since the heat can be efficiently dissipated to the outside by the heat transfer, thermal deformation is further unlikely to occur.

Therefore, when the present inventor diligently investigated the thermal expansion coefficient and the thermal conductivity of the polishing work holding plate, the thermal expansion coefficient was 3 × 10 ⁻⁵ / K or less and the thermal conductivity was 0.4 W. It has been found that such thermal deformation is significantly reduced if it is / mK or more. However, the coefficient of thermal expansion of the resin that has been conventionally coated was 5 × 10 ⁻⁵ / K, and the thermal conductivity was about 0.2 to 0.3 W / mK. Therefore, in order to prevent thermal deformation, the thermal expansion coefficient of the resin is 3 × 10 ⁻⁵ / K or less and the thermal conductivity is 0.4 W / mK by some means.
It is necessary to do above.

Therefore, the inventor of the present invention has conceived that silica is used as a filler instead of the conventionally used resin filled with calcium carbonate as the resin for coating the main body of the work holding plate. Calcium carbonate is 5 in epoxy resin
Can be filled only about 0% by weight, but if it is silica 60
This is because it is possible to fill the resin in a weight percentage or more and the thermal expansion coefficient is small, so that the thermal expansion coefficient and the thermal conductivity of the resin coating the holding plate body can be surely set within the above ranges. The present invention has been completed by scrutinizing various conditions based on the above idea.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto. An example of the method for manufacturing the work holding plate used in the present invention will be described based on the flow chart shown in FIG. First, in step (a), a thermosetting resin, for example, an epoxy resin, and a heat conduction adjusting agent, for example, silica are charged into a stirring and mixing tank and sufficiently defoamed under vacuum to remove air.
When the epoxy resin contains silica, the coefficient of thermal expansion of the epoxy resin should be 3 × 10 ⁻⁵ / K or less,
In order to make the thermal conductivity 0.4 W / mK or more, silica 6
It is preferable to fill 0% by weight or more.

To this end, the silica to be filled has a particle size of 1 to
It is preferable that the particles have a particle size of 10 μm. This is 1 μm
This is because when the silica particles are smaller than the above, the viscosity of the filled resin increases and the resin is not filled with too much silica. Further, in the case of large silica particles having a particle size of more than 10 μm, the resin surface coated on the holding plate has large irregularities, and holding the wafer on the surface may deteriorate the nanotopology. Further, in this case, the large silica particles having a diameter of about 10 μm and a spherical shape
By filling small particles having a size of about 3 μm and having a nearly spherical shape, the filling amount can be increased, the thermal expansion coefficient can be made smaller, and the thermal conductivity can be made higher.

In step (b), the work holding plate body 2 of the work holding plate 1 as shown in FIG. After setting the adjusting plate 32, the thermosetting resin 31 as described above is poured onto the work holding surface 8.

Regarding the characteristics that the work holding plate body 2 coated with the resin should have, the diameter of the through hole 4 should be 0.
2 to 0.5 mm is preferable, and the linear thermal expansion coefficient of the work holding board body material is 1 × 10 ⁻⁵ / K or less and the holding board body 2
It is desirable that the coefficient of thermal expansion is also small, and that the material of the work holding plate body 2 is a sintered body (ceramics) of silicon carbide (SiC). in this way,
When the hole diameter of the through hole 4 is 0.2 mm or more, when the resin layer 3 is formed on the holding surface 8 of the holding plate body 2 with the thermosetting resin 31, the resin 31 does not have a risk of clogging the hole and is 0.5 mm or less. In this case, the traces of holes are less likely to be transferred to the surface of the work during polishing the work due to the hole diameter itself being too large.

When the work holding plate body 2 is made of a material having a low coefficient of thermal expansion, the holding surface of the work holding plate and the work are polished on the polishing device surface plate described later. Since the difference in the amount of thermal deformation of the work holding board body can be reduced, and the deformation of the coated resin can be suppressed, it is possible to maintain the holding surface shape of the work holding board with high accuracy, and work with high flatness. Polishing becomes possible. The work holding plate body may be made of a metal or a ceramic material, but as a material having a low coefficient of thermal expansion, high rigidity, and high corrosion resistance that is not easily corroded by a polishing liquid, the above-mentioned silicon carbide ( SiC) is preferably used.

In step (c), the bar 33 is slid on the coating amount adjusting plate 32 to scrape off excess resin to form a resin layer having a uniform thickness. The thickness of the resin layer 3 that covers the holding surface of the work holding board body 2 is preferably 0.5 to 3 mm. When the thickness of the resin layer 3 of the work holding board 1 is 3 mm or less as described above, the rigidity of the work holding board body 2 is not reduced, and thus more precise work polishing can be performed, and the work holding board main body 2 can be polished to 0.5 mm. With the above, high flatness can be obtained.

Next, in the step (d), the work holding board body 2 coated with the resin 31 is placed in the electric heating furnace 35 together with the resin coating jig 30, and the gas 34 heated from below the resin coating jig 30 is placed. Is started and heating is started while passing through the through hole 4 of the work holding plate body 2, and the entire thermosetting resin 31 is thermoset. In this case, the resin 3 around the through hole 4
1 can be pre-cured and then the remaining resin can be heat-cured. By doing so, the resin in the peripheral portion of the through hole is cured first, so that the through hole 4 can be prevented more effectively. It can be made more reliable. Further, the temperature of the thermosetting gas 34 can be the same as or higher than the thermosetting temperature of the resin, but if it is the same as the thermosetting temperature of the resin, the thermosetting reaction rate of the resin causes the heating of the resin. Since the rate of decrease in viscosity is determined by the above, it is preferable that the resin layer 3 can be formed without blocking the through holes.

Next, in the step (e), the work holding plate body 2 covered with the resin layer 3 is set on the lapping machine 40, and the lapping liquid 43 is dropped from the nozzle 42 while the platen 41 is rotated to drop the resin layer. The surface of 3 is ground and the surface is corrected,
Thoroughly wash in step (f).

Further, in the step (g), the work holding plate body 2 covered with the resin layer 3 after the lapping correction is set in the polishing device 20, and the polishing agent 24 is dropped from the nozzle 23 while rotating the platen 21. The surface of the resin layer 3 is polished to correct the surface, sufficiently washed to complete the work holding plate main body 2, and the work holding plate back plate 5 is attached to the work holding plate main body 2 to manufacture the polishing head 10. The surface of the heat-cured resin layer 3 is first surface-corrected by lapping, and then corrected by polishing on the surface plate of the polishing apparatus 20 to form a more accurate holding surface shape of the holding plate 1. By using this polishing work holding plate 1, polishing work with high flatness can be performed.

By doing so, it is possible to manufacture a work holding plate in which a large amount of silica is added as a heat conduction adjusting agent to the epoxy resin portion of the work holding portion. By adding an appropriate amount of silica as a thermal conductivity modifier, the thermal conductivity of the resin on the surface of the work holding plate is 0.4 W / mK or more, and the thermal expansion coefficient is 3
It is possible to reliably obtain a work holding plate having a ^{density of} × 10 ^-5 / K or less.

Such a work holding plate is mounted on the polishing apparatus as shown in FIG. 1 and the work W such as a wafer is polished as described above. In the present invention, the polishing work holding plate 1
Since thermal deformation hardly occurs during polishing, the nanotopography of the workpiece W after polishing, which has been a problem in the past, can be improved.

In this case, the polishing cloth 22 undergoes deformation having viscoelastic properties during polishing, and the degree of this deformation gradually changes depending on the state of the polishing cloth 22 during polishing. Therefore, even if the work holding surface 8 of the work holding plate 1 is finished flat as described above, the work W after processing may not be flat. Therefore, before holding the back surface of the work W by vacuum suction, the holding surface 8 of the polishing work holding plate 1 covered with the resin is brought into contact with the polishing cloth 22 for polishing, and the shape of the work holding surface 8 is changed to the polishing cloth. After the deformed shape of the work piece 22 is imitated, the back surface of the work piece W is vacuum-sucked and held by the holding surface 8 and then brought into contact with the polishing cloth 22 to polish the front surface of the work piece W, whereby the work holding surface 8 is corrected. Planned,
The flatness of the work can be improved. This method is particularly effective when polishing a thin work such as a wafer.

[0045]

EXAMPLES Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. (Example 1) A work was polished by using the work polishing apparatus 20 having the structure shown in FIG. The resin layer 3 covering the holding surface 8 of the work holding plate body 2 is made of an epoxy resin filled with 70% by weight of silica. The thickness of the resin layer 3 is 1
mm, thermal conductivity 0.5 W / mK, thermal expansion coefficient 1 ×
It was 10 ⁻⁵ / K. The work holding board body 2 has a thickness of 3
It is a 0 mm silicon carbide (SiC) porous plate and has a thermal expansion coefficient of 4 × 10 ⁻⁶ / K. The diameter of the through hole 4 is 0.3
The thing of mm was used.

As a work polishing condition, a polishing load of 30 kP
a, relative speed of polishing 50 m / min, target polishing allowance 10
μm, and the polishing cloth 22 is a non-woven cloth-based polishing cloth, polishing agent 2
Alkaline solution containing colloidal silica as 4 (p
H10.5) was used for polishing. Further, before holding the work W by suction and polishing it, the holding surface 8 of the work holding plate 1 covered with the resin layer 3 was brought into contact with the polishing cloth 22 for polishing. The polishing conditions were the resin layer polishing allowance of 40 μm, and the other conditions were the same as the above-mentioned workpiece polishing conditions.

A silicon wafer having a diameter of 200 mm and a thickness of 735 μm as the work W to be polished is placed on the work holding plate 1.
Was vacuum-adsorbed and held and polished.

The flatness, waviness and nanotopography of the work after polishing were confirmed. The flatness was measured with a capacitance type thickness gauge (Ultra Gauge 9700 manufactured by ADE), and the waviness of the work surface was observed with a magic mirror. The nanotopography was measured by Nanomapper manufactured by ADE under the measurement condition of 2 mm square.

As a result, the flatness of the work is determined by SBIRmax (Site Back-side Id) based on the back surface.
eal Range: value standardized by SEMI standard M1 etc., cell size 25 mm x 25 mm) 0.13
A high flatness of μm was achieved. In addition, no waviness was observed on the surface of the work even with a magic mirror, and high-precision machining was achieved. Nanotopography was also around 10 nm, which was preferable.

(Embodiment 2) The silica filling amount of the epoxy resin coating the holding surface 8 of the work holding plate body 2 is 60% by weight.
The work holding board 1 was produced under the same conditions as in Example 1 except for the above, and the work was polished under the same conditions. Resin layer 3
Thermal conductivity of silica-filled epoxy resin is 0.4W / mK
Met. The coefficient of thermal expansion was 3 × 10 ⁻⁵ / K.

As a result, the flatness was almost the same as that of Example 1, and the nanotopography was slightly worse than that of Example 1, but all around 15 nm were 20 nm or less, which was a good level.

(Comparative Example 1) A work holding plate 1 was prepared under the same conditions as in Example 1 except that the holding surface 8 of the work holding plate body 2 was coated with calcium carbonate-filled epoxy resin, and the work was polished under the same conditions. Was carried out. The thermal conductivity of the calcium carbonate-filled epoxy resin was 0.3 W / mK. The coefficient of thermal expansion was 4 × 10 ⁻⁵ / K.

As a result, the flatness was almost the same as in Example 1, but the waviness of the work surface due to the magic mirror was observed. Nanotopography values around 30 nm are all 20
It was over nm.

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

For example, in the above embodiment, the holding surface
Epoxy resin is used as the resin for coating the heat conduction adjustment
An example is given for the case where silica is filled as the agent
However, the present invention is not limited to this, and covers the holding surface.
The thermal expansion coefficient of resin is 3 × 10 ^-5/ K or less
If so, it is included in the scope of the present invention. With such a resin
For example, resin such as polyamide-imide, or silicone
Listed below are polyamides containing 33% by weight or more of particles.
be able to.

[0056]

According to the present invention, a polishing work holding plate having a highly accurate work holding surface is provided. Therefore, using this, it is possible to manufacture a work having excellent flatness and a waviness-free surface by polishing. In particular, when the work is a semiconductor wafer polished by using the polishing work holding plate of the present invention, it is a wafer with improved nanotopography, and it is possible to reduce focus defects in lithographic exposure in the highly integrated device process. Therefore, the yield of highly integrated devices can be improved.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a polishing apparatus.

2A to 2C are schematic explanatory views of deformation of a resin layer.

3 (a) to 3 (g) are flowcharts showing a manufacturing process of the polishing work holding plate of the present invention.

[Explanation of symbols]

1 ... Polishing work holding board, 2 ... Work holding board body,
3 ... Resin layer, 4 ... Through hole, 5 ... Work holding board back plate,
6 ... Space part (vacuum part), 7 ... Suction path, 8 ... Work holding surface, 10 ... Polishing head, 11 ... Rotation holder, 12 ...
Elastic sheet, 13 ... Pressurized space portion, 14 ... Pressurized air supply passage, 20 ... Polishing device, 21 ... Surface plate, 22 ... Polishing cloth (polishing pad), 23 ... Nozzle (abrasive supply pipe), 2
4 ... Abrasive agent, 30 ... Jig for resin application, 31 ... Thermosetting resin, 32 ... Coating amount adjusting plate, 33 ... Bar, 34 ... Gas, 35 ... Electric heating furnace, 40 ... Lapping machine,
41 ... Surface plate, 42 ... Nozzle, 43 ... Lapping liquid. W ...
Work (wafer).

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Fumio Suzuki             Odaira, Odakura, Saigo Village, Nishishirakawa-gun, Fukushima Prefecture             No. 150 Shin-Etsu Semiconductor Co., Ltd. Semiconductor Shirakawa             In the laboratory (72) Inventor Koji Kitagawa             Odaira, Odakura, Saigo Village, Nishishirakawa-gun, Fukushima Prefecture             No. 150 Shin-Etsu Semiconductor Co., Ltd. Semiconductor Shirakawa             In the laboratory F-term (reference) 3C058 AA07 AB04 CB01 DA17

Claims (9)

[Claims] 1. A polishing work holding plate having a work holding plate main body having a large number of through holes for holding a work by vacuum suction, the holding surface of the holding plate main body being coated with resin.
The coefficient of thermal expansion of the resin coating the holding surface is 3 × 10 ^−5.
/ K or less, a work holding plate for polishing. 2. The polishing work holding plate according to claim 1, wherein the resin coating the holding surface has a thermal conductivity of 0.4 W / mK or more. 3. The resin coating the holding surface is an epoxy resin filled with silica.
Alternatively, the polishing work holding plate according to claim 2. 4. The polishing work holding plate according to claim 3, wherein the silica filled in the epoxy resin is 60% by weight or more of the epoxy resin. 5. The polishing work holding plate according to claim 3, wherein the silica filled in the epoxy resin has a particle size of 1 to 10 μm. 6. A polishing apparatus for a work, comprising the work holding plate for polishing according to any one of claims 1 to 5. 7. A polishing work holding plate for holding a work by vacuum suction is coated with a resin having a thermal expansion coefficient of 3 × 10 ⁻⁵ / K or less, and the back surface of the work is vacuum suction held by the holding surface. Then, a method for polishing a work, which comprises contacting the work with a polishing cloth to polish the surface of the work. 8. The method of polishing a work according to claim 7, wherein the resin coating the holding surface has a thermal conductivity of 0.4 W.
/ MK or more, a method of polishing a work. 9. The polishing method for a work according to claim 7, wherein the holding surface of the polishing work holding plate covered with the resin is held on the polishing cloth before the back surface of the work is vacuum-sucked and held. And a surface of the work is polished by vacuum-holding the back surface of the work by the holding surface and then bringing the work into contact with the polishing cloth.