JPH11320391A - Table for wafer polishing device and manufacture thereof, and polishing method for semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a table for a wafer polishing device to be excellent in heat resistance, thermal impact resistance, wear resistance, and corrosion resistance, and cope with an increase in the bore of a semiconductor wafer, improvement of precision, and enhancement of quality. SOLUTION: This table 2 constitutes a wafer polishing device 1 togetherwith a wafer holding plate 6. By bringing a semiconductor wafer 5, held at the holding surface 6a of a plate 6, into contact with the polishing surface 2a of this table 2, polishing is performed. This table 2 is a dense substance made of a silicon carbide sintered substance having density of at least 2.7 g/cm<3> or thermal conductivity is at least 30 w/mK.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a table for a wafer polishing apparatus, a method for manufacturing the same, and a method for polishing a semiconductor wafer.

[0002]

2. Description of the Related Art Generally, a mirror wafer having a mirror surface can be obtained by slicing a single crystal silicon ingot thinly and polishing it through a lapping step and a polishing step. In particular, when the epitaxial growth layer forming step is performed after the lapping step and before the polishing step, an epitaxial wafer can be obtained. Then, these bare wafers are oxidized,
Various processes such as etching and impurity diffusion are repeatedly performed, and finally a semiconductor device is manufactured (see FIG. 3).

In the above series of steps, it is necessary to polish the device formation surface of a semiconductor wafer by using some means. Therefore, various types of wafer polishing apparatuses (lapping machines, polishing machines, and the like) have been conventionally proposed.

An ordinary wafer polishing apparatus has a table fixed to the upper portion of a cooling jacket, and a pusher for rotatably holding the wafer on its own holding surface so as to bring the semiconductor wafer into sliding contact with the polishing surface of the table. And a plate. The semiconductor wafer is used in a state of being generally adhered to the holding surface of the pusher plate by a thermoplastic wax. As such a conventional table, for example, a table made of alumina or stainless steel is generally known.

[0005]

Since a table for a wafer polishing apparatus is often heated to a high temperature during a polishing operation, a material for forming the table is required to be resistant to thermal deformation and thermal shock. Further, since the frictional force constantly acts on the polished surface of the table, the material for forming the table is required to have wear resistance. Further, in recent years, demand for large-diameter and high-precision wafers has been increasing, and it is considered that a material satisfying high rigidity and a low coefficient of thermal expansion should be selected as a material for forming a table. That is, in order to realize a large-diameter and high-precision wafer, it is desirable that the temperature of the wafer itself be small and the stress applied to the semiconductor wafer be small.

However, an alumina table is
There is a disadvantage that the amount of thermal deformation is large and weak against thermal shock. The stainless steel table has relatively high rigidity, but has a disadvantage that it is a metal material and therefore has a large coefficient of thermal expansion and is inferior in wear resistance as compared with a ceramic material.

[0007] Under the circumstances described above, silicon carbide (SiO ₂ ) having high rigidity, low coefficient of thermal expansion, high thermal conductivity and abrasion resistance and having high resistance to thermal deformation and thermal shock is used as a material for forming a table. It may be good. However, it is expected that it is difficult to ensure sufficient corrosion resistance (specifically, oxidation resistance when an alkaline solution is used, etc.) simply by using a table made of silicon carbide. Therefore, even if polishing is performed using this, it may be substantially difficult to obtain a high-quality semiconductor wafer due to contamination due to leakage of impurities in the sintered body.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first object of the present invention is to provide a semiconductor wafer having excellent heat resistance, thermal shock resistance, abrasion resistance, and corrosion resistance, a semiconductor wafer having a large diameter, and high precision. An object of the present invention is to provide a table for a wafer polishing apparatus capable of coping with high quality and high quality.

A second object of the present invention is to provide a method capable of reliably manufacturing the above excellent table. A third object of the present invention is to provide a method of polishing a semiconductor wafer which is extremely suitable for achieving high precision and high quality of a semiconductor wafer since the semiconductor wafer can be uniformly polished. It is in.

[0010]

According to the first aspect of the present invention, a semiconductor wafer held on a holding surface of a wafer holding plate constituting a wafer polishing apparatus is slid. The gist of the table having a polishing surface to be in contact with is a table for a wafer polishing apparatus made of a dense body made of silicide ceramics or carbide ceramics having a density of 2.7 g / cm ³ or more.

According to a second aspect of the present invention, there is provided a table having a polishing surface on which a semiconductor wafer held on a holding surface of a wafer holding plate constituting a wafer polishing apparatus is slidably contacted. Is 2.7g / cm
³ or more at which a silicon carbide sintered body made of a dense body, thermal conductivity and its gist the table wafer polishing apparatus which is characterized in that at 30 w / mK or more.

According to a third aspect of the present invention, in the second aspect, 0.15% by weight to 1.0% by weight of boron and 0.1% by weight.
It contains 5% to 10% by weight of free carbon.

According to a fourth aspect of the present invention, in the second aspect, 0.5 to 10% by weight of aluminum and 0.5 to 10% by weight of free carbon are contained.

According to a fifth aspect of the present invention, in any one of the second to fourth aspects, the table is a dense body made of a silicon carbide sintered body starting from β-type silicon carbide powder. I have.

According to a sixth aspect of the present invention, there is provided a method of manufacturing a table for a wafer polishing apparatus according to the second aspect, wherein boron and its compound, aluminum and its compound are added to 100 parts by weight of silicon carbide powder. A first step of uniformly mixing 0.3 parts by weight to 20 parts by weight of a sintering aid comprising at least one selected from a compound and carbon; and forming the mixture obtained in the first step into a predetermined shape. Second
And forming the compact obtained by the second step in 1800
A method for manufacturing a table for a wafer polishing apparatus, which includes a step of firing within a temperature range of 2 to 400 ° C.

According to the seventh aspect of the present invention, the semiconductor wafer is held on the holding surface of the wafer holding plate constituting the wafer polishing apparatus, and the density is 2.7 g / cm ^3.
The above-mentioned dense body made of a silicon carbide sintered body, wherein the semiconductor wafer is brought into sliding contact with a polished surface of a table having a thermal conductivity of 30 w / mK or more while rotating the semiconductor wafer. A gist of the present invention is a method for polishing a semiconductor wafer, characterized by performing polishing.

Hereinafter, the "action" of the present invention will be described. According to the invention described in claim 1, this table has a density of 2.
Since it is a dense body of 7 g / cm ³ or more, the bonding between crystal grains is strong and the number of pores is extremely small, so that it has excellent corrosion resistance as compared with the related art. In addition, since such a dense body is made of silicide ceramics or carbide ceramics, it has relatively high rigidity, a low coefficient of thermal expansion, a high thermal conductivity, a high abrasion, and is resistant to thermal deformation and thermal shock. Has properties. Therefore, if polishing is performed using this table, it is possible to cope with an increase in diameter, accuracy and quality of the semiconductor wafer.

According to the second aspect of the present invention, since this table is a dense body having a density of 2.7 g / cm ³ or more, the bonding between the crystal grains is strong and the number of pores is very small. It has excellent corrosion resistance. In addition, since such a dense body is made of a silicon carbide sintered body, it has extremely high rigidity, a low coefficient of thermal expansion, a high thermal conductivity, a high abrasion, and a property of being extremely resistant to thermal deformation and thermal shock. Have. Therefore, if polishing is performed using this table, it is possible to reliably cope with an increase in diameter, accuracy, and quality of the semiconductor wafer.

Here, the density of the table is 2.7 g / c.
m ³ or more, and moreover 3.0 g /
cm ³ or more, particularly 3.1 g / c
More preferably, it is at least m ³ . If the density is low, the bonding between crystal grains in the sintered body becomes weak or the number of pores increases, so that sufficient corrosion resistance and wear resistance cannot be secured.

The thermal conductivity of the sintered body is required to be 30 w / mK or more, and furthermore, 80 w / mK to 200 w
/ MK or more. If the thermal conductivity is too small, temperature variation tends to occur in the sintered body, which may hinder the increase in diameter, accuracy, and quality of the semiconductor wafer. Conversely, the higher the thermal conductivity is, the more preferable it is. On the other hand, if the thermal conductivity exceeds 200 w / mK, it is difficult to supply a cheap and stable material.

According to the third aspect of the present invention, by containing boron and free carbon satisfying the above preferred ranges, they act as a sintering aid, thereby promoting grain growth. Therefore, the grain boundaries of the crystal grains in the sintered body are reduced and the density is increased, resulting in corrosion resistance, rigidity, thermal conductivity,
Heat resistance, thermal shock resistance, and abrasion resistance are increased.

Here, boron is 0.15% by weight to 1.0% by weight.
% By weight, preferably 0.2% to 0.5% by weight.
More preferably 0.3% to 0.4% by weight
It is particularly good that Also, free carbon is 0.5% by weight.
10 to 10% by weight, and 1.0% to 5.0% by weight.
% By weight, more preferably from 3.0% by weight to 6.0% by weight.
It is particularly preferred that the amount is by weight.

According to the fourth aspect of the present invention, by containing aluminum and free carbon satisfying the above preferred ranges, they function as a sintering aid, thereby promoting grain growth. Therefore, the grain boundaries of the crystal grains in the sintered body are reduced and the density is increased, so that the corrosion resistance, rigidity, heat conductivity, heat resistance, thermal shock resistance, and wear resistance are increased.

Here, aluminum is 0.5% by weight to 1% by weight.
0% by weight, preferably 3.0% to 10% by weight
Is more preferably 5.0% by weight to 10% by weight. In addition, free carbon is 0.5% by weight or more.
It is preferably 10% by weight, more preferably 1.0% to 5.0% by weight, particularly preferably 3.0% by weight to 6.0% by weight.

According to the fifth aspect of the present invention, a dense body made of a silicon carbide sintered body is obtained by using a β-type silicon carbide powder as a starting material, so that other types (α-type silicon carbide powder and amorphous carbonized powder) can be obtained. Large plate crystals are more likely to be formed than when silicon powder is selected. Therefore, the grain boundaries of the crystal grains in the sintered body are reduced, and the thermal conductivity and the like are further increased.

Of course, α-type silicon carbide powder or amorphous silicon carbide powder can be used instead of β-type silicon carbide powder. Of course, these powders may be used alone or in combination of two or more (α-type + β-type, α-type + amorphous, β-type + amorphous, α-type + β-type + Amorphous).

According to the sixth aspect of the present invention, the uniform mixture of the silicon carbide powder and the sintering aid produced through the first step is formed into a predetermined shape by the subsequent second step. Become. Then, the molded body is fired at a high temperature by passing through the third step, and becomes a sintered body having extremely dense and suitable physical properties.

With respect to 100 parts by weight of silicon carbide powder, 0.3 to 20 parts by weight of a sintering aid composed of at least one selected from boron and its compounds, aluminum and its compounds, and carbon. Must be uniformly mixed.

These materials, which act as sintering aids, significantly increase the crystal growth rate of silicon carbide. In addition, these substances diffuse to the corners of the compact in the firing temperature range of the silicon carbide sintered body, thereby contributing to the formation of nuclei of the plate-like crystals, and thus providing a reliable densification.

Here, boron and its compound include:
For example, 1) boron alone, 2) aluminum diboride,
3) boron carbide, 4) boron nitride, 5) boron oxide,
6) chromium boride; 7) lanthanum boride; Among them, 1)-
The choice of 5) is preferred. Of course, as for the substances listed here, one kind may be used alone, or two or more kinds may be used in combination.

Examples of aluminum and its compounds include 1) aluminum alone, 2) aluminum diboride, 3) aluminum carbide, 4) aluminum nitride,
5) Aluminum oxide and the like. Of course, as for the substances listed here, one kind may be used alone, or two or more kinds may be used in combination.

Examples of carbon include: 1) phenolic resin, 2) lignin sulfonate, 3) polyvinyl alcohol, 4) corn starch, 5) molasses, 6) coal tar pitch, 7) organic substances such as alginate, and the like. Further, inorganic substances such as 8) carbon black and 9) acetylene black are exemplified. Of course, as for the substances listed here, one kind may be used alone, or two or more kinds may be used in combination. The carbon may be a carbon content contained in a boron compound or an aluminum compound. In addition, when carbon coexists with boron and its compound, and aluminum and its compound, a pore becomes easy to become fine.

The sintering aid is used in an amount of preferably 0.3 to 20 parts by weight, more preferably 5.0 to 20 parts by weight, and particularly preferably 10 to 20 parts by weight. Most preferably, it is a part. If the amount of the sintering aid is too small, the effect of increasing the crystal growth rate of silicon carbide becomes insufficient. Conversely, even if the amount of the sintering aid is extremely increased, the effect of increasing the crystal growth rate will not be greatly increased, but rather the physical properties of the sintered body may be reduced due to the increase in impurities.

The silicon carbide compact obtained in the second step must be fired within a predetermined temperature range. Here, within the predetermined temperature range is 1800 ° C. to 2400 ° C., preferably 2000 ° C. to 2300 ° C. If the firing temperature is too low, not only is it difficult to increase the crystal grain size, but also many pores remain in the sintered body. Conversely, if the firing temperature is too high, the decomposition of silicon carbide starts, resulting in a reduction in the strength of the sintered body.

As described above, according to the manufacturing method of the present invention, a table excellent in heat resistance, thermal shock resistance, abrasion resistance, corrosion resistance and the like can be reliably manufactured.

According to the seventh aspect of the invention, as a result of the semiconductor wafer rotating and slidingly contacting the polishing surface, one side surface of the semiconductor wafer is uniformly polished by the polishing surface. Since the above-mentioned table made of silicon carbide is excellent in thermal conductivity, abrasion resistance, corrosion resistance and the like, it is unlikely to cause temperature variation and leakage of impurities during polishing.
Therefore, it is possible to reliably cope with an increase in diameter, accuracy and quality of a semiconductor wafer.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A wafer polishing apparatus 1 according to one embodiment of the present invention will be described below in detail with reference to FIGS.

FIG. 1 shows a wafer polishing apparatus 1 according to this embodiment.
Is schematically shown. The table 2 constituting the wafer polishing apparatus 1 has a disk shape and is made of a silicon carbide sintered body. The upper surface of the table 2 is a polishing surface 2a for polishing the semiconductor wafer 5. A polishing cloth (not shown) is attached to the polishing surface 2a. Such a table 2 includes a cooling jacket 3 also having a disc shape.
It is attached to the upper part using bolts and the like (not shown). The cooling jacket 3 itself is horizontally supported by a cylindrical rotating shaft 4. A flow path is formed inside the cooling jacket 3. Cold water W as a cooling fluid is circulated through this flow path.

The wafer polishing apparatus 1 has a large number (two in FIG. 1 for convenience of illustration) of wafer holding plates 6. As a material for forming the wafer holding plate 6, for example, glass, a ceramic material such as alumina, or a metal material such as stainless steel is used. A pusher bar 7, which is a part of a driving device (not shown), is fixed to the center of one side surface (non-holding surface 6b) of each wafer holding plate 6. Each pusher bar 7 horizontally supports each wafer holding plate 6 with the holding surface 6a facing the polishing surface 2a of the table 2 therebelow. Further, each pusher bar 7 can not only rotate with the wafer holding plate 6 but also move up and down within a predetermined range. The semiconductor wafer 5 is adhered to the holding surface 6a of the wafer holding plate 6 using, for example, a thermoplastic wax. Needless to say, the semiconductor wafer 5 may be suctioned to the holding surface 6a by evacuation or electrostatically. At this time, the polished surface 5a of the semiconductor wafer 5 needs to face the polished surface 2a of the table 2.

When the apparatus 1 is a lapping machine, that is, an apparatus for polishing a wafer that has undergone a slicing step in a bare wafer process, the wafer holding plate 6 holds the semiconductor wafer 5 against the polished surface 2a under a predetermined pressing force. It is preferable that the sliding contact be made. This is because even if a pressing force is applied by such a wafer holding plate 6 (that is, a pusher plate), since the epitaxial growth layer is not formed, there is no need to worry about separation. The same applies to a case where the apparatus 1 is a polishing machine for manufacturing a mirror wafer, that is, an apparatus that performs polishing without performing an epitaxial growth step on a wafer that has undergone the lapping step.

On the other hand, when the apparatus 1 is a polishing machine for manufacturing an epitaxial wafer, that is, an apparatus which performs an epitaxial growth step on a wafer having undergone the lapping step and then polishes the wafer, the wafer holding plate 6 is provided with a semiconductor. It is preferable that the wafer 5 is brought into sliding contact with the polishing surface 2a almost without applying a pressing force. This is because the silicon epitaxial growth layer is easier to peel than single crystal silicon. This is basically the same when the apparatus 1 is a machine for performing chemical mechanical polishing (CMP) after various film forming steps.

Hereinafter, several examples which embody the present embodiment will be described with reference to the table of FIG.

[0043]

EXAMPLES [Examples 1A and 1B] In the production of Example 1B, "Beta Random (trade name)" manufactured by IBIDEN Co., Ltd. was used as silicon carbide powder containing 94.6% by weight of β-type crystal. . The silicon carbide powder had an average crystal grain size of 1.3 μm and contained 1.5% by weight of boron and 3.6% by weight of free carbon.

In the first step, the silicon carbide powder 1
After mixing 5 parts by weight of polyvinyl alcohol and 300 parts by weight of water with respect to 00 parts by weight, the mixture was mixed in a ball mill for 5 hours to obtain a uniform mixture. After drying the mixture for a predetermined time to remove a certain amount of water, an appropriate amount of the dried mixture was collected and granulated.

In the second step, the granules of the mixture obtained in this manner are subjected to 50 kg /
Molded at a pressure of cm ² . The density of the obtained green body was 1.2 g / cm ³ .

In the third step, the green compact was placed in a graphite crucible capable of shutting off outside air, and was fired using a Tamman-type firing furnace. The firing was performed in an argon gas atmosphere at 1 atm. Further, at the time of baking, heating was performed at a heating rate of 10 ° C./min to a maximum temperature of 2300 ° C., and thereafter, the temperature was maintained for 2 hours. Observation of the obtained sintered body showed an extremely dense three-dimensional network structure in which plate-like crystals were entangled in multiple directions.

The density of the obtained sintered body was 3.1 g /
cm ³ , and the thermal conductivity was 150 w / mK. Boron contained in the sintered body was 0.4% by weight, and free carbon was 1.8% by weight.

Finally, one side of the sintered body produced through the third step was subjected to polishing using a silicon carbide polishing jig. As a result, a table 2 having a polished surface 2a having a surface roughness suitable for polishing the semiconductor wafer 5 was completed.

The table 2 of Example 1A obtained in this manner was set in the various polishing apparatuses 1 described above, and the semiconductor wafers 5 of various sizes were polished. No thermal deformation or the like was observed. Moreover, C is easily exposed to a strong alkaline solution.
When applied to the MP machine, the same table 2
Was not oxidized and was confirmed to be excellent in corrosion resistance. This is presumed to be due to the fact that the alkali solution was less likely to enter the inside of the sintered body due to the increased density due to the reduced porosity of the table 2.

Further, the semiconductor wafer 5 obtained through polishing by the various polishing apparatuses 1 was not damaged at all irrespective of its size, and no large warpage occurred. In other words, extremely high precision and high quality semiconductor wafers 5
Was proved to be obtained.

On the other hand, in the fabrication of Example 1A, FIG.
In addition to setting the materials, conditions, and the like described in the table, the first to third steps were basically performed in accordance with the above procedure. The silicon carbide powder used was α-type, and was specifically “OY15 (trade name)” manufactured by Yakushima Denko Corporation.

The density of the sintered body of Example 1A was 3.1 g / c
m ³ , and thermal conductivity was 125 w / mK. Boron contained in the sintered body was 0.4% by weight, and free carbon was 1.8% by weight. That is, the sintered body of Example 1B using β-type silicon carbide powder as a starting material tended to have a thermal conductivity about 20% higher than that of the sintered body of Example 1A.

One side of the sintered body produced through the third step was polished using a silicon carbide polishing jig. As a result, a table 2 having a polished surface 2a having a surface roughness suitable for polishing the semiconductor wafer 5 was completed.

The table 2 of Example 1A obtained in this manner was set in the various polishing apparatuses 1 described above, and the semiconductor wafers 5 of various sizes were polished. The results were almost the same as those of Example 1B. Results were obtained.

That is, no thermal deformation or the like was observed on the table 2 in any of the polishing apparatuses 1 of any type. In addition, even when applied to a CMP machine which is easily exposed to a strong alkaline solution, the table 2 was not oxidized, and it was confirmed that the table 2 was excellent in corrosion resistance.
Further, the semiconductor wafer 5 obtained through polishing by the various polishing apparatuses 1 had no scratches at all irrespective of its size, and did not cause any significant warpage. That is, it has been proved that a semiconductor wafer 5 of extremely high precision and high quality can be obtained. [Examples 2A and 2B] In the production of Example 2B, "Beta Random (trade name)" manufactured by IBIDEN Co., Ltd. was used as silicon carbide powder containing 94.6% by weight of β-type crystal as in Example 1B. Using. This silicon carbide powder has a
Having an average crystal grain size of 4 μm and 10% by weight
Of aluminum and 5.5% by weight of free carbon. On the other hand, in the preparation of the sample of Example 2A, “OY15 (trade name)” manufactured by Yakushima Electric Works, Ltd., which is α-type silicon carbide powder, was used as in Example 1A.

After performing the first and second steps in accordance with the procedure of Example 1A, in the third step, the formed body is charged into a graphite crucible and fired using a tanman type firing furnace. Was. The firing was performed in an argon gas atmosphere at 1 atm. Further, at the time of baking, heating was performed at a heating rate of 15 ° C./min to a maximum temperature of 2200 ° C., and thereafter, the temperature was maintained for 5 hours. Observation of the obtained sintered body showed an extremely dense three-dimensional network structure in which plate-like crystals were entangled in multiple directions.

The density of the obtained sintered body of Example 2B was 3.
It was 1 g / cm ³ and the thermal conductivity was 170 w / mK. Aluminum contained in the sintered body was 2.6% by weight, and free carbon was 3.2% by weight. The density of the obtained sintered body of Example 2A was 3.1 g / cm ³ ,
Thermal conductivity was 142 w / mK. Aluminum contained in the sintered body was 2.6% by weight, and free carbon was 3.2% by weight. That is, the sintered body of Example 2B using β-type silicon carbide powder as a starting material tended to have a thermal conductivity about 20% higher than that of the sintered body of Example 2A.

Finally, one side surface of the sintered body manufactured through the third step was subjected to polishing using a silicon carbide polishing jig. As a result, a table 2 having a polished surface 2a having a surface roughness suitable for polishing the semiconductor wafer 5 was completed.

Examples 2A and 2B obtained in this way
Table 2 was set in the above various polishing apparatuses 1 and the semiconductor wafers 5 of various sizes were polished. As a result, almost the same excellent results as in Examples 1A and 1B were obtained.

That is, no thermal deformation or the like was observed on the table 2 in any of the polishing apparatuses 1 of any type. In addition, even when applied to a CMP machine which is easily exposed to a strong alkaline solution, the table 2 was not oxidized, and it was confirmed that the table 2 was excellent in corrosion resistance.
Further, the semiconductor wafer 5 obtained through polishing by the various polishing apparatuses 1 had no scratches at all irrespective of its size, and did not cause any significant warpage. That is, it has been proved that a semiconductor wafer 5 of extremely high precision and high quality can be obtained. [Examples 3A, 3B, 4A, 4B] In the production of Examples 3B and 4B, "beta-random (trade name)" manufactured by IBIDEN Co., Ltd., which is a β-type silicon carbide powder, was used as in Example 1B. . On the other hand, in the preparation of the samples of Examples 3A and 4A, "OY15 (trade name)" manufactured by Yakushima Denko KK, which is an α-type silicon carbide powder, was used as in Example 1A. Then, the materials, conditions, and the like described in the table of FIG. 2 were set, and the first to third steps were performed basically in accordance with the procedure of Example 1A.

The density of the obtained sintered body of Example 3B was 3.
1 g / cm ³ and the thermal conductivity was 132 w / mK. The sintered body contained 0.7% by weight of boron and 3.8% by weight of free carbon. The density of the obtained sintered body of Example 3A was 3.1 g / cm ³ , and the thermal conductivity was 1 g / cm ^3.
It was 10 w / mK. The contents of boron and free carbon were the same. That is, the sintered body of Example 3B using β-type silicon carbide powder as a starting material tended to have a thermal conductivity about 20% higher than that of the sintered body of Example 3A.

The density of the obtained sintered body of Example 4B was 2.
7 g / cm ³ and thermal conductivity was 96 w / mK. Aluminum contained in the sintered body was 1.6% by weight, and free carbon was 3.3% by weight. In addition, the obtained Example 4
The density of the sintered body of A was 2.7 g / cm ³ , and the thermal conductivity was 80 w / mK. The contents of boron and free carbon were the same. That is, the sintered body of Example 4B using β-type silicon carbide powder as a starting material tended to have a thermal conductivity about 20% higher than that of the sintered body of Example 4A.

Of course, these 3A, 3B, 4A, 4
As for B, favorable results comparable to those of Examples 1A, 1B, 2A and 2B were obtained. [Comparative Examples 1 and 2] In Comparative Examples 1 and 2, the materials and conditions described in the table of FIG. 2 were set, and the first to third steps were performed basically in accordance with the procedure of Example 1A. did.

However, in Comparative Example 1, the amount of the sintering aid was set outside the preferred range (specifically, the amount of boron was less than 0.15% by weight). As a result, the density of the obtained sintered body was 2.3 g / cm ³ , and the thermal conductivity was 20 w / mK.
The sintered body contained 0.05% by weight of boron and 1.0% by weight of free carbon.

In Comparative Example 2, the amount of the sintering aid was set outside the preferred range (specifically, the amount of aluminum was more than 10% by weight), and the firing temperature was outside the preferred range (2000 ° C.).
(300 ° C. lower than the temperature). As a result, the density of the obtained sintered body was 2.0 g / cm ³ , and the thermal conductivity was 22 w /
mK. Aluminum contained in the sintered body was 0.09% by weight and free carbon was 2.8% by weight.

Therefore, when the tables of the above two comparative examples were set in the above various polishing apparatuses 1 and the semiconductor wafers 5 of various sizes were polished, various defects (thermal deformation, abrasion, erosion) were found on the tables. , Oxidation, etc.). In addition, the accuracy and quality of the semiconductor wafer 5 obtained through polishing were far below those of Examples 1A to 4B.

Therefore, according to the present embodiment, the following effects can be obtained. Here, only typical ones are listed. (1) According to this embodiment, the table 2 excellent in heat resistance, thermal shock resistance, abrasion resistance and corrosion resistance can be realized, and the semiconductor wafer 5 can be made larger in diameter, higher in precision and higher in quality. It will be possible to respond reliably.

(2) According to the manufacturing method shown in this embodiment, the growth of the plate-like crystal is effectively promoted during firing, so that the above-mentioned excellent table 2 can be reliably manufactured.

(3) According to the method for polishing a semiconductor wafer 5 of this embodiment, the semiconductor wafer 5 can be uniformly polished by the excellent table 2 described above. Therefore,
This is extremely suitable for achieving higher precision and higher quality of the semiconductor wafer 5.

The embodiment of the present invention may be modified as follows. The polishing surface 2a of the table 2 may be completely flat as in the embodiment, or may be formed in a slightly spherical shape (flatness: 0.5 μm to 5 μm).

Instead of moving the wafer holding plate 6 up and down, a structure may be used in which the table 2 is moved up and down. ◎ As silicide ceramics other than silicon carbide, for example, silicon nitride (Si ₃ N ₄ ), sialon, etc. may be selected as long as they satisfy the condition of a dense body having a density of 2.7 g / cm ³ or more. It is acceptable.

As the carbide ceramics other than silicon carbide, boron carbide (B ₄₎ may be used as long as it satisfies the condition of a dense body having a density of 2.7 g / cm ³ or more.
It is also acceptable to select C) or the like.

Next, in addition to the technical ideas described in the claims, technical ideas grasped by the above-described embodiments will be enumerated below. (1) In a mirror wafer having a surface to be polished formed by polishing on sliced single crystal silicon on at least one side thereof, the mirror wafer is held on a holding surface of a wafer holding plate constituting a wafer polishing apparatus. A dense body made of a silicon carbide sintered body having a density of 2.7 g / cm ³ or more, which is manufactured through a polishing step of rotating and sliding contact with a polishing surface of a table having a thermal conductivity of 30 w / mK or more. Mirror wafer. According to the invention described in the technical idea 1, high quality can be achieved.

(2) After performing epitaxial growth on the sliced single-crystal silicon and polishing the same layer, an epitaxial wafer having a surface to be polished formed on at least one side thereof is constituted by a wafer polishing apparatus. A dense body made of a silicon carbide sintered body having a density of 2.7 g / cm ³ or more while being held on the holding surface of the wafer holding plate having a thermal conductivity of 30 w / m 3
An epitaxial wafer manufactured through a polishing process in which the polishing surface of the table is K or more and is brought into rotary contact with the polishing surface. According to the invention described in the technical idea 2, high quality can be achieved.

[0075]

As described in detail above, according to the first aspect of the present invention, the semiconductor wafer is excellent in heat resistance, thermal shock resistance, abrasion resistance, and corrosion resistance, and has a large diameter, high precision, and high accuracy of a semiconductor wafer. It is possible to provide a wafer holding plate for a wafer polishing apparatus that can respond to quality improvement.

According to the second to fifth aspects of the present invention, the heat resistance, the thermal shock resistance, the wear resistance and the corrosion resistance are extremely excellent, and the semiconductor wafer can reliably cope with a large diameter, high precision and high quality of the semiconductor wafer. A possible wafer holding plate for a wafer polishing apparatus can be provided.

According to the third and fourth aspects of the present invention, the denseness of the sintered body is increased, so that the corrosion resistance, rigidity, wear resistance, heat conductivity, etc. of the table are reliably increased. According to the fifth aspect of the invention, the thermal conductivity and the like of the table are more reliably increased.

According to the sixth aspect of the present invention, it is possible to provide a method capable of reliably manufacturing the above excellent table. According to the seventh aspect of the present invention, there is provided a semiconductor wafer polishing method which is extremely suitable for achieving high precision and high quality of a semiconductor wafer because the semiconductor wafer can be uniformly polished. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a wafer polishing apparatus according to an embodiment of the invention.

FIG. 2 is a table showing manufacturing conditions and sintered body characteristics in each example and each comparative example.

FIGS. 3A and 3B are flowcharts for explaining an outline of a manufacturing procedure of a semiconductor device.

[Explanation of symbols]

1. Wafer polishing device, 2. Table for wafer polishing device,
2a: polishing surface, 5: semiconductor wafer, 6: wafer holding plate, 6a: holding surface.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Naoyuki Jimbo 1- 1 north of Ibigawa-cho, Ibi-gun, Gifu Prefecture Ibiden Ogakikita Plant

Claims (7)

[Claims] 1. A table having a polishing surface on which a semiconductor wafer held by a holding surface of a wafer holding plate constituting a wafer polishing apparatus is slidably contacted has a density of 2.7.
A table for a wafer polishing apparatus comprising a dense body made of silicide ceramic or carbide ceramic having a g / cm ³ or more. 2. A table having a polishing surface with which a semiconductor wafer held on a holding surface of a wafer holding plate constituting a wafer polishing apparatus is slidably contacted, said table having a density of 2.7 g / cm ^3. A table for a wafer polishing apparatus, which is a dense body made of a silicon carbide sintered body as described above and has a thermal conductivity of 30 w / mK or more. 3. The wafer polishing apparatus according to claim 2, wherein the composition contains 0.15% to 1.0% by weight of boron and 0.5% to 10% by weight of free carbon. table. 4. The table for a wafer polishing apparatus according to claim 2, wherein the table contains 0.5% to 10% by weight of aluminum and 0.5% to 10% by weight of free carbon. 5. The wafer polishing apparatus according to claim 2, wherein the table is a dense body made of a silicon carbide sintered body starting from β-type silicon carbide powder. Equipment table. 6. A method for manufacturing a table for a wafer polishing apparatus according to claim 2, wherein said compound is selected from boron and its compound, aluminum and its compound, and carbon with respect to 100 parts by weight of silicon carbide powder. 0.3 parts by weight of at least one sintering aid
A first step of uniformly mixing 20 parts by weight, a second step of molding the mixture obtained in the first step into a predetermined shape, and a molding obtained in the second step of 1800 ° C. to 24 ° C.
Baking in a temperature range of 00 ° C. 7. A dense body made of a silicon carbide sintered body having a semiconductor wafer held on a holding surface of a wafer holding plate constituting a wafer polishing apparatus and having a density of 2.7 g / cm ³ or more. And polishing the semiconductor wafer by bringing the semiconductor wafer into sliding contact with a polishing surface of a table having a thermal conductivity of 30 w / mK or more while rotating the semiconductor wafer.