JP2006095637A - SiC SUBSTRATE FOR PROCESSING POLISHING PAD - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust surface conditions of a polishing pad at a low cost. <P>SOLUTION: Before polishing a target substrate using the polishing pad, the surface conditions of the polishing pad are adjusted by sliding an SiC substrate on the polishing pad, the SiC substrate containing elements other than Si, C, and O in an amount of less than 1.0 mass%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the present invention, when polishing a desired substrate using a polishing pad, the SiC for polishing pad processing used as the dedicated substrate when the surface state of the polishing pad is adjusted by sliding the dedicated substrate with respect to the polishing pad in advance. Regarding the substrate.

  Along with the reduction in LSI design rules due to the progress of silicon semiconductor microfabrication technology, the number of elements integrated in a semiconductor chip continues to increase, and the density of wiring connecting elements has further increased. Along with this, the narrower pitch of the wiring in the chip and the multilayer wiring are further advanced, and the importance of so-called CMP (Chemical Mechanical Polishing) for flattening the surface of the semiconductor device with high accuracy is further increased. It is increasing.

CMP is a polishing method that enables both a polishing rate to be secured and defects in the material to be polished (defects caused by polishing) to be reduced by superimposing a chemical polishing action on a mechanical polishing action. For CMP, for example, a polishing pad made of abrasive grains such as silica, a slurry that is a polishing liquid whose hydrogen ion index (pH value) is adjusted, and a polyurethane resin or the like is used.
For example, when polishing a material substrate for manufacturing a semiconductor device, the material substrate is brought into contact with the polishing pad while slurry is distributed on the surface of the polishing pad, and the material substrate and the polishing pad are rotated relative to the material substrate. Then, the material substrate is polished by sliding the polishing pad.

In polishing a material substrate by such a CMP apparatus, the surface state of the polishing pad is particularly important. For example, when the polishing pad surface has poor flatness and the polishing pad surface has large irregularities (particularly when there are large protrusions), the polishing rate becomes unstable and scratches on the surface of the material substrate This causes a problem that occurs. In addition, when the polishing of the material substrate is started in a state where the slurry and abrasive grains are not uniformly and sufficiently spread on the surface of the polishing pad, an in-plane distribution occurs in the degree of polishing of the material substrate (amount of wear on the surface to be polished).
In the polishing by the CMP apparatus, at the stage where the polishing of the material substrate is started, for example, abrasive grains and slurry are uniformly and sufficiently distributed on the surface of the polishing pad, and no excessive unevenness is present on the surface of the polishing pad (removed). The polishing pad surface needs to be sufficiently adapted to the polishing conditions of the material substrate and be in a stable state.
The state in which the polishing pad surface is sufficiently adapted and stable to the polishing conditions of the material substrate is a state in which the material substrate is polished at a stable polishing rate in the polishing of the material substrate. This refers to a state where the slurry is uniformly and sufficiently spread and the excess unevenness of the polishing pad is removed.

Conventionally, in a CMP apparatus, the surface state of a polishing pad has been adjusted prior to polishing of a material substrate, for example, in order to make the surface of the polishing pad stable. Patent Document 1 listed below discloses a seasoning ring used for flattening a polishing pad surface after a used polishing pad is replaced or a polishing pad surface after polishing a material substrate using the polishing pad. Yes. In the seasoning ring described in Patent Document 1, for example, a substrate (seasoning ring) in which approximately four leaf-shaped holes are formed in the center is slid on a polishing pad. In Patent Document 1, by using a seasoning ring having such a shape, it is possible to accustom the polishing pad more flatly than in the case of using a donut-shaped seasoning ring having a general shape. As described above, the conventional seasoning ring has a shape different from that of the material substrate to be actually polished and is made of a material different from the material substrate (for example, SUS << stainless steel >>). As described above, when the polishing pad is slid only by using a seasoning ring having a shape and a material different from those of the material substrate, the surface of the polishing pad is not sufficiently stable in accordance with the polishing conditions of the material substrate. Therefore, conventionally, prior to the material substrate, under the same polishing conditions as the material substrate polishing conditions (for example, the same slurry, abrasive grains, polishing load, table rotation speed, head rotation speed, slurry supply method, etc.) The surface state of the polishing pad was adjusted by polishing (preliminary polishing) a preliminary polishing substrate made of the same material. As described above, by performing preliminary polishing, the surface state of the polishing pad is adjusted to a stable state prior to polishing the material substrate.
Japanese Patent Laid-Open No. 10-180640

For example, when a silicon oxide film wafer having a silicon oxide film (SiO ₂ film) formed on the surface of a silicon (Si) wafer is used as a material substrate (main polishing wafer), the silicon oxide film on the surface is conventionally spared. For polishing, a silicon oxide film is formed on the surface of the dummy silicon wafer to produce a dummy silicon oxide film wafer (preliminarily polished wafer). Then, prior to polishing the main polishing wafer, by performing preliminary polishing for polishing the silicon oxide film surface of the preliminary polishing wafer using the same polishing pad as that used for polishing the main polishing wafer, The surface condition of the polishing pad was adjusted.

Thus, in order to adjust the surface state of the polishing pad, when the preliminary polishing of the silicon oxide film of the preliminary polishing wafer, which is the same silicon oxide film as the main polishing wafer, is performed, the oxide film of the preliminary polishing wafer In the preliminary polishing, polishing is performed at a relatively high polishing rate similar to that of the product.
In the conventional method of adjusting the surface state of the polishing pad by performing preliminary polishing, the amount of wear of the silicon oxide film in one preliminary polishing is relatively large as described above. When preliminary polishing is repeated repeatedly, the silicon oxide film on the surface of the preliminary polishing wafer disappears with a relatively small number of preliminary polishings.
Thus, in order to adjust the surface condition of the polishing pad, when preliminary polishing is performed (when the preliminary polishing wafer is polished), the number of preliminary polishing that can be performed using one preliminary polishing wafer is relatively small. Few.

  In order to make the polishing pad stable, such as when sequentially polishing a large number of main polishing wafers, it is necessary to frequently adjust the surface state of the polishing pad. However, in the conventional method of preparing a preliminary polishing wafer and performing preliminary polishing to adjust the surface state of the polishing pad, as described above, the number of preliminary polishing operations that can be performed using one preliminary polishing wafer. Is relatively small, and it is necessary to frequently produce new pre-polished wafers. In order to produce a new pre-polishing wafer, it is necessary to form a silicon oxide film on the surface of the silicon wafer, and there is a problem that a great cost is required for manufacturing the pre-polishing wafer.

  The present invention has been made paying attention to the above-mentioned conventional problems, and an object thereof is to provide a polishing pad processing SiC substrate capable of reducing the cost for adjusting the surface state of the polishing pad. .

  In order to achieve the above object, the present invention is a dedicated substrate that is slid against the polishing pad in advance to adjust the surface state of the polishing pad when polishing a desired substrate using the polishing pad. A polishing pad processing SiC substrate is provided, wherein a mass fraction of an element different from any of Si, C, and O is less than 1.0 (mass%).

In addition, when polishing a desired substrate using a polishing pad, the substrate is a dedicated substrate that is slid with respect to the polishing pad in advance to adjust the surface state of the polishing pad, and includes Si, C, and O Provided is a SiC substrate for processing a polishing pad, wherein a mass fraction of an element different from any of the elements is less than 1.0 (mass ppm).
It is more preferable that these SiC substrates for processing a polishing pad have a density of 2.9 (g / cm ³ ) or more.

  The SiC substrate is preferably a substrate made of SiC crystal grown by a CVD method. It is more preferable that the crystal system is made of 3C SiC crystal and the surface is a (111) orientation plane.

  The SiC substrate for polishing pad processing of the present invention can be suitably implemented, for example, in chemical mechanical polishing. The surface state of the polishing pad may be adjusted after the dressing process of the polishing pad. Further, after the adjustment of the surface state of the polishing pad, the polishing may be performed for each of the different substrates in succession a plurality of times.

Incidentally, SiC substrate polishing pad process, a substrate to be polished is a substrate where the SiO ₂ film is formed on the surface of the Si substrate, the SiO ₂ film surface chemically by the polishing pad surface condition is adjusted It can be suitably used in a polishing process in which mechanical mechanical polishing is performed. Examples of the slurry used in the chemical mechanical polishing at this time include a slurry containing silica as abrasive grains.

  In the polishing pad processing SiC substrate of the present invention, the substrate to be polished is a substrate in which a tungsten film is formed on the surface of the Si substrate, and the surface of the tungsten film is adjusted by the polishing pad whose surface state is adjusted. It can be suitably used in a polishing process in which chemical mechanical polishing is performed. Examples of the slurry used in chemical mechanical polishing at this time include a slurry containing alumina grains as abrasive grains.

The SiC substrate for polishing pad processing of the present invention has a very low impurity concentration, and does not contaminate the polishing pad surface when used for adjusting the polishing pad surface state in the polishing step.
Moreover, the SiC substrate for polishing pad processing of the present invention has high wear resistance, and the amount of wear when used for adjusting the surface state of the polishing pad is small. For this reason, it can be used repeatedly many times to adjust the surface state of the polishing pad, and the cost associated with the polishing step can be reduced.
Further, the surface of the SiC substrate for polishing pad processing of the present invention is hydrophilic, and can be suitably used for adjusting the polishing pad surface state in the polishing step of the hydrophilic silicon oxide film (SiO ₂ film). . For this reason, it is not necessary to prepare a pre-polishing wafer in the silicon oxide film polishing in order to adjust the surface state of the polishing pad, and the cost for forming the silicon oxide film for preparing the pre-polishing wafer can be reduced.

Hereinafter, the SiC substrate for polishing pad processing of the present invention will be described.
FIG. 1 is a schematic perspective view illustrating a chemical mechanical polishing apparatus 10 (hereinafter simply referred to as apparatus 10) that adjusts the polishing pad surface state using the SiC substrate for polishing pad processing of the present invention.

  As shown in FIG. 1, the apparatus 10 includes a platen unit 20, a polishing head unit 30, a slurry control unit 40, and a dresser unit 50.

The platen unit 20 includes a disk-shaped surface plate 24 whose upper surface (upper surface) in FIG. 1 is a plane, a polishing pad 22 affixed to the upper surface of the surface plate 24, and the surface plate 24. A platen rotating means 26 that rotates in the direction of arrow A in FIG. 1 is provided with a rotation axis that is perpendicular to the surface and passing through the center of the upper surface.
The polishing pad 22 is a known CMP polishing pad made of foamed polyurethane, for example, and has a number of fine holes (fine holes) formed on its surface.

  The polishing head unit 30 is disposed on the upper side of the platen unit 20. The polishing head unit 30 holds a wafer to be polished (substrate to be polished) 12 (or a SiC wafer 14 to be described later) to be polished with the surface to be polished of the wafer 12 to be polished facing the polishing pad 22 ( In other words, the wafer holding means 32 (held downward in FIG. 1) and the surface to be polished of the wafer 12 held by the wafer holding means 32 are pressed against the upper surface of the polishing pad 22 of the polishing unit 20 And a wafer pressing / driving means 34 for pressing. The wafer pressurizing / driving means 34 also rotates the wafer 12 in the direction of arrow B in FIG. 1 with the axis perpendicular to the surface to be polished of the wafer 12 passing through the center of the wafer 12 to be polished as the rotation axis.

The slurry control unit 40 includes a dropping nozzle 42 that drops and supplies the slurry 46 to the surface of the polishing pad 22, and a slurry supply unit 44 that supplies the slurry to the dropping nozzle 42. The dropping nozzle 42 and the slurry supply means 44 are connected by a hose 48, and the slurry 46 is supplied from the slurry supply means 44 to the dropping nozzle 42 through the hose 48.
The slurry 46 is a well-known CMP slurry of a solid-liquid dispersion system in which fine abrasive particles (abrasive grains) are dispersed in an aqueous solution (abrasive liquid) containing a reagent such as a pH adjuster. For example, a known slurry such as silica slurry (pH = 10 to 11) in which fumed silica particles (silica particles) obtained by thermally decomposing silicon chloride gas are dispersed in a KOH-added aqueous solution (polishing liquid) is used.

The dresser unit 50 includes a rod 54, a dresser 56 provided at the tip of the rod 54 (the left end in FIG. 1), a support shaft 52 that is connected to the rod 54 and extends in a direction perpendicular to the rod 54, and a support. In addition to supporting the rod 54 via the shaft 52, there is a dresser driving means 58 that moves the rod 54 and the dresser 56 by rotating the support shaft 52 or moving it up and down in FIG.
The dresser 56 is a diamond grindstone, for example. The support shaft 52 is moved downward in FIG. 1 by the dresser driving means 58, and the dresser 56 is pressed against the upper surface of the polishing pad 22. At the same time, as the support shaft 52 rotates, the dresser 56 moves on the surface of the polishing pad 22 while being pressed against the polishing pad 22.
The dresser unit 50 is driven in this manner in a dressing process described later, and the surface of the polishing pad 22 is shaved and removed by the dresser 56. The dressing process and the function of the dresser unit 50 will be described in detail later.

FIGS. 2A and 2B are flowcharts showing an example of a method for polishing a wafer to be polished, which is performed in the chemical mechanical polishing apparatus 10, respectively.
2A and 2B show an example in which an oxide film CMP is performed by the apparatus 10 on a silicon oxide film wafer having a silicon oxide film formed on the surface of the silicon wafer. FIGS. 2A and 2B are flowcharts showing an example in which the silicon oxide film surface of the wafer 12 to be polished, which is a silicon oxide film wafer, is polished by the apparatus 10.

  First, the flowchart of 1st Embodiment shown to Fig.2 (a) is demonstrated. In the flowchart shown in FIG. 2A, after a predetermined number of wafers 12 are continuously polished, a dressing process is performed to maintain the processing characteristics (ie, polishing characteristics) of the apparatus 10, The polishing of the wafer 12 to be polished is started again. In the first embodiment, the surface state of the polishing pad 22 is adjusted prior to resuming the polishing of the wafer 12 to be polished after the dressing process.

First, a predetermined number of wafers 12 are polished continuously (step S110). FIG. 3 is a schematic sectional view for explaining the polishing of the wafer 12 to be polished by the apparatus 10 shown in FIG.
In the apparatus 10, the surface of the wafer 12 to be polished, that is, the silicon oxide film surface is held by the wafer holding mechanism 32 so as to face the surface of the polishing pad 22. In this state, while the slurry 46 is dropped onto the surface of the polishing pad 22 from the dropping nozzle 42, the surface to be polished of the wafer 12 to be polished, that is, the silicon oxide film surface is predetermined on the surface of the polishing pad 22 by the wafer pressurizing / driving means 34 Is pressed (pressurized) and rotated in the direction of arrow B in FIGS. 1 and 2. During this rotation, the surface plate 24 also rotates in the direction of arrow A in FIGS. 1 and 2, and the polishing pad 22 disposed on the upper surface of the surface plate 24 also rotates with this rotation. The slurry 46 is configured by dispersing abrasive grains 49 in an abrasive liquid 47.
As described above, while the wafer to be polished 12 and the polishing pad 22 are rotating independently, the slurry 46 is continuously dropped from the dropping nozzle 42, and the gap between the wafer to be polished 12 and the polishing pad 22 is continuously dropped. The slurry 46, that is, the abrasive liquid 47 and the abrasive grains 49 are evenly distributed.

As the polishing target wafer 12 and the polishing pad 22 rotate independently, the polishing target surface of the polishing target wafer 12 is mechanically affected by friction between the polishing pad 22 and the abrasive grains 49 and the polishing target surface of the polishing target wafer 12. It is polished by. Simultaneously with the polishing by the mechanical action, the surface to be polished of the wafer to be polished 12 is polished by the chemical action due to the chemical reaction between the polishing liquid 47 and the surface to be polished of the wafer 12. In the apparatus 10, the wafer 12 to be polished is polished in this way.
At this time, as the slurry 46, for example, a known slurry for polishing a silicon oxide film (oxide film CMP) in which silica particles (silica particles) are dispersed in an ammonia-based aqueous solution adjusted to pH = 10 may be used. .

  While a predetermined number of wafers 12 are being polished continuously (S110), the surface of the polishing pad 22 is in a stable state, that is, the abrasive grains 49 and the abrasive liquid 47 are on the surface of the polishing pad 22. The surface to be polished (the surface of the silicon oxide film) of the wafer to be polished 12 is polished at a stable polishing rate with uniform and sufficient spread and removal of excess irregularities of the polishing pad 22.

  However, if a plurality of wafers 12 to be polished are continuously polished in the apparatus 10, as the polishing proceeds, the fine holes on the surface of the polishing pad 22 gradually become debris, reaction products, slurry solids, etc. Clogging occurs. The fine holes contribute to polishing by the mechanical action of the surface to be polished of the wafer 12 to be polished. When the fine holes are clogged, the polishing characteristics of the polishing pad 22 are deteriorated. That is, as the clogging of the fine holes progresses, the polishing rate of the surface to be polished of the wafer 12 to be polished decreases, the in-plane distribution of the polishing rate on the polishing surface increases, or the polishing surface of the wafer 12 to be polished The frequency of occurrence of scratches in the case increases.

In the flowchart shown in FIG. 2A, in order to prevent such deterioration of the polishing characteristics due to clogging of the fine holes of the polishing pad 22, a predetermined number of wafers 12 are polished continuously and then dressed on the polishing pad. Processing is performed (step S112).
The dressing process is performed by pressing the dresser 56 against the surface of the polishing pad 22 and scraping and removing the surface of the polishing pad 22. That is, the support shaft 52 is moved downward in FIG. 1 by the dresser driving means 58 shown in FIG. 1, and the dresser 56 provided on the rod 54 is pressed against the upper surface of the polishing pad 22. For example, the surface portion of the polishing pad 22 is scraped off by the dresser 56 when the dresser 56 slides on the surface of the polishing pad 22 in a state where the high-hardness dresser 56 made of a diamond grindstone is pressed against the surface of the polishing pad 22. It is.

  At this time, while the dresser 56 is pressed against the surface of the polishing pad 22, the surface plate 26 is rotated by the surface plate rotating means 26, and the surface of the polishing pad 22 is rotated in the direction of arrow A in FIG. As the support shaft 52 of the dresser unit 50 rotates, the dresser 56 relatively moves on the surface of the polishing pad 22. As the polishing pad 22 and the dresser 56 move relative to each other in this manner, the dresser 56 moves so as to cover all of the radial direction of the polishing pad 22 and have a uniform locus. As a result, the entire surface of the polishing pad 22 can be uniformly removed by the dresser 56. In the apparatus 10, the dressing process is performed in this way.

  In the first embodiment shown in FIG. 2A, the surface condition of the polishing pad 22 after the dressing process is adjusted (polishing pad adjustment) prior to resuming polishing of the wafer 12 to be polished (S114). FIG. 4 is a schematic sectional view for explaining the polishing pad adjustment in the apparatus 10 shown in FIG. The surface of the polishing pad 22 after the dressing process is free from clogging of fine holes, but the surface is roughened by being scraped off by the dresser 56, and the surface irregularities are relatively large. When the polishing pad 22 which is a silicon oxide film wafer is polished using the polishing pad 22 in such a state, the polishing rate of the surface to be polished is lowered or the polishing rate on the surface to be polished is within the plane as described above. Various problems arise such that the distribution deteriorates and the frequency of occurrence of scratches on the polished surface increases.

In this polishing pad adjustment, the surface of the polishing pad 22 after dressing is adjusted to a stable state. In such a polishing pad adjustment, the SiC wafer 14 as the SiC substrate for polishing pad processing is mounted on the wafer holding means 32 of the polishing apparatus 10, and the SiC wafer 14 is used as the wafer 12 to be polished. This is performed by sliding the SiC wafer 14 with respect to the polishing pad 22 in the manner of polishing the SiC wafer 14 under similar conditions.
The SiC wafer 14 used here will be described in detail later.

  That is, while the slurry 46 is dropped onto the surface of the polishing pad 22 from the dropping nozzle 42, one surface of the SiC wafer 14 is pressed against the surface of the polishing pad 22 by a predetermined pressure by the wafer pressurizing / driving means 34 (applying) 1) and rotates in the direction of arrow B in FIGS. During this rotation, the surface plate 24 also rotates in the direction of arrow A in FIGS. 1 and 2, and the polishing pad 22 disposed on the upper surface of the surface plate 24 also rotates with this rotation. The slurry 46 is configured by dispersing abrasive grains 49 in an abrasive liquid 47. During this time, the slurry 46 is continuously dripped from the dripping nozzle 42, and the slurry 46, that is, the abrasive liquid 47 and the abrasive grains 49, spread evenly between the polished wafer 12 and the polishing pad 22.

  By this polishing pad adjustment, the surface of the polishing pad 22 after dressing is adjusted to a stable state. That is, by sliding the SiC wafer 14 against the polishing pad 22 under the same polishing conditions as the polishing condition of the wafer 12 to be polished, for example, the abrasive grains 47 and the abrasive liquid 49 are applied to the surface of the polishing pad 22. Uniform and sufficient distribution can be achieved, and excess irregularities on the surface of the polishing pad 22 can be removed. By such an effect, the surface of the polishing pad 22 can be polished at a stable polishing rate.

When the adjustment of the surface state of the polishing pad 22 is completed and the polishing pad 22 becomes stable, the wafer 12 to be polished is subsequently polished (S116).
Such polishing of the wafer 12 to be polished is performed similarly to the polishing of the wafer 12 to be polished in S112. In the polishing of the wafer to be polished 12 in S116, from the time when the polishing of the first wafer to be polished 12 is started by performing the polishing pad process (that is, from the time when polishing of the wafer to be polished 12 is restarted). The polishing pad 22 is in a stable state. Therefore, the polishing of the polishing surface of the wafer to be polished 12 can be stably performed from the polishing of the first wafer to be polished 12.
The first embodiment of the polishing method implemented including the adjustment of the polishing pad surface state using the SiC substrate for polishing pad processing of the present invention is performed as described above.

Next, a second embodiment shown in FIG.
In the second embodiment shown in FIG. 2B, after a predetermined number of wafers 12 to be polished are continuously polished, the polishing pad 22 is waited for a certain period of time without any particular processing (apparatus). An example in the case where the polishing of the wafer 12 to be polished is resumed will be described.
In the second embodiment, the surface state of the polishing pad 22 is adjusted prior to resuming the polishing of the wafer 12 to be polished after the apparatus 10 is in the idling state. The second embodiment will be described in detail below.

Also in the second embodiment, as in the first embodiment, first, a plurality of wafers 12 to be polished are continuously polished (step S120). The wafer 12 to be polished in the second embodiment is also polished by the apparatus 10 in the same manner as in the first embodiment. However, in the second embodiment, as in the first embodiment, the polishing is not continuously performed until the clogging of the polishing pad 22 is sufficiently advanced, and the surface state of the polishing pad 22 is sufficiently stable. At the stage where it is in a state, the polishing is once terminated.
The second embodiment is suitable, for example, when a plurality of lots are polished intermittently when the number of wafers 12 to be polished per lot to be continuously polished is small (in the case of small lot production). Is the method.

Once the polishing of the wafer 12 to be polished is finished, the apparatus 10 is in an idling state. The idling state is a standby state until the next wafer to be polished 12 is polished, and the surface of the polishing pad 22 is not particularly treated (the dressing process as in the first embodiment is not performed). ).
If this idling state continues for a long time, drying of the abrasive liquid 47 of the slurry 46 dispersed on the surface of the polishing pad 22 proceeds. Further, the agglomeration of the abrasive grains 49 on the surface of the polishing pad 22 and the remaining polishing waste also proceeds. When the polishing of the wafer 12 to be polished is started in this state, the polishing rate of the surface to be polished 12 decreases, the in-plane distribution of the polishing rate of the surface to be polished increases, or scratches on the surface to be polished Problems such as an increased frequency of scratches occur.

  Further, in order to prevent the problem of drying of the polishing pad 22, water may continue to flow on the surface of the polishing pad 22 during idling so that the polishing pad 22 does not dry. In that case, there is also a problem that the slurry concentration becomes thin. That is, by continuing the flow of water, the concentration of the abrasive liquid 47 becomes thin or the pH value changes. Further, the abrasive grains 49 also flow out from the polishing pad 22, and the number of abrasive grains 49 on the surface of the polishing pad 22 also decreases. As described above, when the polishing of the polishing target wafer 12 is started in a state where the concentration of the abrasive liquid 47 is reduced or the number of the abrasive grains 49 is decreased, the polishing rate of the polishing target surface of the polishing target wafer 12 is decreased, There arises a problem that the in-plane distribution of the polishing rate of the polishing surface becomes large.

In the second embodiment, after the apparatus 10 is in an idling state, the surface condition of the polishing pad 22 in the idling state (polishing pad adjustment) is adjusted (polishing pad adjustment) before resuming polishing of the wafer 12 to be polished (step S124). ).
This polishing pad adjustment is performed in the same manner as the polishing pad adjustment (step S114) in the first embodiment described above. That is, as in the first embodiment, the SiC wafer 14 as the SiC substrate for polishing pad processing is mounted on the wafer holding means 32 of the polishing apparatus 10, and the polishing condition of the wafer 12 to be polished is determined using the SiC wafer 14 as the wafer 12 to be polished. The SiC wafer 14 is slid with respect to the polishing pad 22 in the manner of polishing the SiC wafer 14 under the same conditions as in FIG.

  By such a polishing pad process, for example, the agglomeration of abrasive grains 49 and residual polishing debris on the surface of the polishing pad 22 caused by the progress of drying of the abrasive liquid 47 on the surface of the polishing pad 22 is dispersed, and the polishing pad surface is ground. The surface of the polishing pad 22 is in a state where the polishing target wafer 12 can be polished at a stable polishing rate because the grains and the slurry are uniformly and sufficiently distributed and the slurry concentration is stabilized.

When the polishing pad adjustment is completed and the surface state of the polishing pad 22 becomes stable, the wafer 12 to be polished is subsequently polished (S126). Polishing of the wafer 12 to be polished is performed in the same manner as in S120 described above. In the polishing of the wafer 12 to be polished after the polishing pad adjustment, the state of the surface of the polishing pad 22 is stable from the time when the polishing of the first wafer 12 to be polished is started. The polishing wafer 12 can be stably polished.
The second embodiment of the polishing method for a wafer to be polished, which is performed including the adjustment of the polishing pad surface state using the SiC substrate for polishing pad processing of the present invention, is performed as described above.

  In both the first embodiment and the second embodiment described above, a silicon oxide film wafer having a silicon oxide film formed on the silicon wafer surface is used as the wafer to be polished 12, and the silicon oxide film surface is polished (so-called Oxide film CMP) was performed. In the present invention, for example, a silicon metal film wafer in which tungsten (W) or copper (Cu) or the like is formed on the silicon wafer surface is used as the polishing wafer 12, and the metal film formed on the silicon metal film wafer surface. May be polished (so-called metal CMP may be performed). The wafer to be polished in the present invention is not particularly limited.

The present invention provides an SiC substrate for polishing pad processing that is used as a polishing pad processing substrate that is slid with respect to the polishing pad when adjusting the surface state of the polishing pad.
In the first and second embodiments described above, the SiC wafer 14 used as the polishing pad processing substrate when adjusting the polishing pad is a polishing pad processing SiC wafer (SiC substrate) provided by the present invention. A SiC wafer for processing a polishing pad, wherein the mass fraction of an element different from any of O and O is less than 1.0 (mass%).

  When adjusting the polishing pad of the polishing pad 22, such a high-purity SiC wafer 14 is used as a polishing pad processing substrate, so that even when the SiC wafer 14 is slid with respect to the polishing pad 22, the wafer 12 to be polished is used. Impurities such as metal ions, which adversely affect the operation of products manufactured by processing the metal, hardly remain on the surface of the polishing pad 22. Moreover, SiC has high hardness and excellent wear resistance. For this reason, when the SiC wafer 14 is used as a polishing pad processing substrate, the amount of wear on the surface of the SiC wafer 14 in one polishing pad adjustment is very small. Therefore, one SiC wafer 14 can be repeatedly used as a polishing pad processing substrate.

  Further, SiC is hydrophilic, and the surface of the SiC wafer 14 is hydrophilic in the same manner as the surface to be polished (silicon oxide film surface) of the wafer 12 to be polished in the first and second embodiments described above. For this reason, by using the SiC wafer 14 as the polishing pad processing substrate, the state of the surface of the polishing pad 22 at the time of polishing the wafer 12 to be polished can be faithfully reproduced in the polishing pad adjustment. For example, when the surface of the hydrophilic SiC wafer 14 is pressed against the surface of the polishing pad 22 to which the slurry 46 is supplied, the abrasive liquid 47 and the abrasive grains 49 of the slurry 46 are coated on the surface of the wafer 12 to be polished that is hydrophilic. Similar to the case where the polishing surface (silicon oxide film surface) is pressed against the surface of the polishing pad 22, it easily spreads to the gap between the surface of the SiC wafer and the surface of the polishing pad 22.

Moreover, SiC is excellent in the contact resistance with respect to various chemicals, such as an acid and an alkali. By using the SiC wafer 14 as the polishing pad processing substrate, the polishing pad 22 is not contaminated by the polishing liquid during the polishing pad processing. Moreover, only the deposits by polishing can be easily removed by various chemical solutions after the polishing pad treatment.
By using a SiC wafer in which the mass fraction of an element different from any of Si, C, and O is less than 1.0 (mass%) as a dedicated substrate used for polishing pad adjustment, such various effects are achieved. Have

FIG. 5 is a flowchart of an example of a method for producing a SiC wafer 14 which is a SiC substrate for processing a polishing pad according to the present invention.
The SiC wafer 14 produced by the flowchart shown in FIG. 5 is a wafer made of 3C—SiC crystal, which is one of the polytypes of SiC crystal, and an SiC wafer having the (111) crystal plane as the surface. In this example, an example of the SiC wafer 14 having a polytype of 3C-SiC as the SiC substrate for polishing pad processing is shown, but the polytype of the SiC wafer that is the SiC substrate for polishing pad processing of the present invention is, for example, 4H- SiC may be used and is not particularly limited.

  First, as shown in FIG. 5, a 3C-SiC crystal is grown on a graphite substrate surface by CVD (crystal orientation growth) to produce a 3C-SiC crystal (step S130), and the substrate is burned. The 3C-SiC crystal body is detached to produce a 3C-SiC substrate (step S132). This 3C-SiC substrate is mechanically polished (step S134), and finally, after chamfering and cleaning the wafer edge portion, a predetermined inspection is performed (step S136), and a high-purity SiC wafer 14 is produced. Details of each step will be described later.

6 (a) to 6 (d) are diagrams for explaining the outline of the SiC wafer manufacturing method shown in the flowchart of FIG.
As shown in FIG. 6, first, a disk-shaped graphite substrate 60 having a predetermined size made of high-purity graphite that matches the size of the SiC wafer 14 to be manufactured is prepared (FIG. 6A). Thereafter, the disc-shaped graphite substrate 60 is put into a CVD apparatus, the inside of the apparatus (furnace) is heated and held at a predetermined temperature (for example, 1000 to 1600 ° C.), and the inside of the furnace is subjected to a predetermined pressure (for example, 1.. 3 kPa). Then, together with hydrogen gas (H ₂ ) that is a carrier gas, SiCl ₄ , C ₃ H _8, or the like that is a raw material of SiC is supplied by 5 to 20% by volume, and a SiC layer is formed on the surface of the graphite substrate 60. The 3C-SiC crystal body 62 is formed into a desired thickness (for example, 0.5 to 1 mm) (FIG. 6B). (Step 130 in FIG. 5)

  Thereafter, the graphite substrate 60 on which the 3C-SiC crystal body 62 is formed is taken out from the CVD apparatus, and the peripheral surface of the 3C-SiC crystal body 62 is ground and cut by machining to expose the peripheral surface of the graphite substrate 60. (FIG. 6C). Then, the graphite substrate 60 sandwiched between the ground 3C-SiC crystals 62 is put into a furnace at 900 to 1400 ° C., oxygen is supplied, the graphite substrate 60 is burned and removed, and two sheets are removed. An SiC substrate 70 is obtained. (Step 132 in FIG. 4)

Thereafter, mechanical polishing is performed on the surface of SiC substrate 70 (step 134 in FIG. 4). This mechanical polishing is performed using, for example, diamond abrasive grains. Then, after the mechanical polishing, as a finishing process, the wafer edge portion is chamfered and cleaned by a known method, and then a predetermined inspection is performed (step 136 in FIG. 4) to obtain a high-purity polishing substrate substrate. A SiC wafer 14 is produced (FIG. 6D).
For example, the high-purity SiC wafer 14 that is the polishing pad processing substrate of the present invention is manufactured in this manner.

FIG. 7 is a diagram for explaining an outline of the crystal structure of SiC in the SiC wafer 14 thus obtained. The SiC crystal structure in the SiC wafer 14 produced as described above is a 3C-SiC crystal, and as shown in FIG. 7, the crystal structure is a zinc-blende crystal, and the carbon atom C and the silicon atom Si are composed of A hexagonal lattice is formed. Such a 3C—SiC crystal has a layer in which carbon atoms C are arranged and a layer in which silicon atoms Si are arranged along the direction of the [111] axis (the direction indicated by the arrow 82 in FIG. 4). Alternatingly arranged. The bonds between the layers are as follows. Each of the atoms in the Si layer and the C layer is bonded to three atoms in the adjacent layer by three dangling bonds, and each of the Si layer and the C layer. Bonding portions B in which each atom is bonded to one atom of an adjacent layer by one dangling bond are alternately repeated. Bonding by one dangling bond at the bonding part B is very weak compared to bonding by three dangling bonds at the bonding part A. When the crystal is divided, such as when the wafer is cleaved, the bonding part B is always present. Will be disconnected. Thereby, for example, the bond is cut at a broken line 84 in FIG. 7 to cut in a direction parallel to the (111) plane, and the SiC wafer 14 having the (111) plane as a surface is obtained. Becomes a so-called Si surface where a layer of silicon atoms Si appears, and the other surface becomes a so-called C surface where a layer of carbon atoms C appears. This is the same when polishing is performed. When the (111) plane is polished, a silicon atom Si layer appears on one surface, and when the opposite surface is polished, carbon atoms C A layer appears.
It is known that the C surface of the SiC substrate has a higher etching rate and higher workability than the Si surface in both mechanical polishing and CMP polishing.

  Table 1 below shows the measurement results of the mass fractions of various elements contained in the SiC wafer in an example of an SiC wafer (CVD-SiC wafer) manufactured using such a CVD method. The measurement results shown in Table 1 below are values obtained by measurement using a known glow discharge mass spectrometer.

As shown in Table 1, the above-described CVD-SiC wafer manufactured using the CVD method has a mass fraction of an element different from any of Si, C, and O of less than 0.5 (mass ppm). It is a high purity SiC wafer. Further, as a result of conversion from mass and volume, the above-mentioned CVD-SiC wafer has a density of 3.2 (g / cm ³ ), which is almost equal to the ideal density of SiC crystal of 3.21 (g / cm ³ ). It was a SiC wafer of density.

By using such a high-purity SiC wafer as a polishing pad processing substrate and adjusting the surface state of the polishing pad 22, almost no impurities such as metal ions are generated from the SiC wafer, and the polishing pad 22 is almost contaminated. There is an effect that the polishing pad can be adjusted without any problems.
On the other hand, when an SiC wafer (low-purity SiC wafer) having a mass fraction of an element different from any of Si, C, and O of 1.0 (mass%) or more is used as a polishing pad processing substrate, the polishing pad is adjusted. Inside, impurities such as metal ions are cut out from the SiC wafer. The impurities cut out in this way are mixed into the slurry or adhered to the polishing pad. Thus, when the polishing pad is adjusted using a low-purity SiC wafer, the surface of the polishing pad and the slurry are contaminated. When polishing a wafer to be polished using such a contaminated polishing pad or slurry, there arises a problem that the wafer to be polished is contaminated (impurities such as metal ions adhere to the wafer to be polished).
In the present invention, polishing is performed by adjusting the surface state of the polishing pad using a high-purity SiC wafer having a mass fraction of an element different from any of Si, C, and O of less than 1.0 (mass%). The polishing pad can be adjusted with little contamination of the pad.

The SiC wafer for polishing pad processing provided by the present invention is a SiC wafer in which the mass fraction of elements different from any of Si, C, and O (hereinafter referred to as impurity fraction) is less than 1.0 (mass%). Any other method may be used, and the present invention is not limited to the CVD-SiC wafer manufactured using the CVD method as described above.
However, in order to further reduce contamination of the polishing pad in the polishing pad process, the SiC wafer provided by the present invention is preferably as highly pure as possible.
That is, the SiC wafer of the present invention is more preferably an SiC wafer having an impurity fraction of less than 1.0 (mass ppm), and further, an SiC wafer having an impurity fraction of less than 0.5 (mass ppm). Better.
If the CVD method is used, as described above, a high-purity CVD-SiC wafer having an impurity fraction of less than 0.5 (mass ppm) can be produced with high accuracy. As described above, the SiC wafer for processing a polishing pad provided by the present invention is preferably a high-purity SiC wafer produced by a CVD method.

Moreover, SiC is a very hard substance said to be second only to diamond. The SiC wafer has a hardness (such as Mohs hardness) that is sufficiently harder than, for example, a silicon oxide film (SiO ₂ ) that is a material to be polished in the wafer to be polished 12, tungsten (W), copper (Cu), or the like. ing.
For this reason, in the adjustment of the surface state of the polishing pad in oxide film CMP, metal CMP, etc., the case where the SiC wafer, which is the SiC substrate for polishing pad processing of the present invention, is used as the polishing pad processing substrate is more conventional. Compared to the case where a pre-polishing wafer made of the same material as the wafer to be polished that has been used as the processing substrate is used as the polishing pad processing substrate (that is, when pre-polishing is performed), the polishing pad 22 The amount of wear of the polishing pad-treated substrate that contacts and slides is much less.
The high-purity polishing pad processing SiC wafer provided by the present invention has sufficient wear resistance as a polishing pad processing substrate.

However, when it is desired to further reduce the amount of wear of the polishing pad-treated substrate in the polishing pad adjustment, it is preferable to use a SiC wafer having a higher density, that is, having fewer crystal defects and higher wear resistance. As the polishing pad processing substrate of the present invention, it is preferable to use a SiC wafer of high purity and high density (for example, 2.9 (g / cm ³ ) or more).
For example, when a SiC wafer (low density SiC wafer) having a SiC density of less than 2.9 (g / cm ³ ) is used for polishing pad adjustment, there are relatively many crystal defects and low wear resistance. A part of SiC is lost inside and adheres to the surface of the polishing pad or remains in the slurry. When polishing a wafer to be polished using such a polishing pad or slurry, scratches are generated on the surface of the wafer to be polished. In addition, a low-density SiC wafer has many crystal defects and is porous, and there are many voids on the surface and inside. As described above, in a porous low-density SiC wafer, impurities are likely to enter the void portion of the SiC wafer when the polishing pad is adjusted, and the surface is easily contaminated. In addition, it is difficult to remove impurities that have entered by cleaning, and if the polishing pad is adjusted with a contaminated low-density SiC wafer, the polishing pad itself is contaminated. Furthermore, a low-density SiC wafer has problems such as low mechanical strength such as fracture strength, sometimes causing cracks and the like during repeated use, and low durability.

As the polishing pad processing substrate of the present invention, a SiC wafer having high purity and high density (for example, 2.9 (g / cm ³ ) or more) having less contamination due to crystal defects and higher wear resistance. Is preferably used. If the CVD method is used, as described above, a high-density (and high-purity) CVD-SiC wafer substantially equivalent to the ideal density of SiC crystal of 3.21 (g / cm ³ ) can be produced with high accuracy. . The SiC wafer for polishing pad processing provided by the present invention is not particularly limited, but it is more preferably a high-purity and high-density Si wafer produced using a CVD method.

In addition, as described above, in a polytype 3C CVD-SiC wafer having a (111) plane as a surface, one surface is always a so-called Si plane in which a silicon atom Si layer appears, and the other surface is composed of carbon atoms C. This is the so-called C-plane where the layer appears. The C surface of the CVD-SiC wafer has a higher etching rate and higher workability than the Si surface in both mechanical polishing and CMP polishing. When the polishing pad adjustment is performed using such a CVD-SiC wafer, the wear amount of the CVD-SiC wafer (polishing pad processing substrate) in one polishing pad adjustment is a surface that slides on the polishing pad ( Hereinafter, it is different depending on whether the above-mentioned Si surface or C surface is used as the sliding surface. That is, the wear rate of the CVD-SiC wafer differs depending on whether the sliding surface is the Si surface or the C surface.
That the wear rate of the CVD-SiC wafer (polishing pad processing substrate) is different means that the frictional state between the sliding surface and the polishing pad 22 or the grindstone 49 is different when adjusting the polishing pad. That is, depending on whether the sliding surface is the Si surface or the C surface, for example, the frictional heat generated when adjusting the polishing pad is different, and the temperature of the slurry 46 is also different when adjusting the polishing pad. For this reason, the state of the surface of the polishing pad 22 at the end of polishing pad adjustment differs depending on whether the sliding surface is the Si surface or the C surface. If a polytype 3C CVD-SiC wafer having a (111) plane as the polishing pad processing substrate is used, the polishing pad 22 is in a desired state when the polishing pad surface treatment is completed. It can be selected whether the surface is a Si surface or a C surface.
According to the CVD method, it is possible to produce a SiC wafer having a highly accurate crystal orientation on the surface.

Table 2 and Table 3 below show the polishing pad processing substrate for each polishing pad adjustment in each wafer when the polishing pad adjustment is performed using a wafer made of various materials as the polishing pad processing substrate. Indicates the amount of wear.
In Table 2, each wafer is prepared by using a slurry in which silica particles are dispersed as abrasive grains in an ammonia-based abrasive liquid having a pH value adjusted to 10 that has been conventionally used as a slurry for oxide film CMP. The amount of wear of the polishing pad-treated substrate when adjusting the polishing pad for 2 minutes each time is shown.
The amount of wear of the polishing pad processing substrate per polishing pad adjustment shown here is obtained by converting the amount of abrasion of the polishing pad processing substrate when polishing pad adjustment for 2 minutes is performed 100 times in total. Value.

Table 2 shows three types of silicon oxide wafers (conventional examples), sintered SiC wafers, and SiC wafers (CVD-SiC wafers) that have been conventionally used for polishing pad adjustment in oxide film CMP. 2 shows the amount of wear (abrasion depth) of the polishing pad processing substrate when the polishing adjustment is performed under the above-described conditions using the above wafer. In addition, about the CVD-SiC wafer, the amount of wear is shown for each of the cases where the sliding surface is the Si surface and the C surface.
For the silicon oxide film wafer, the silicon oxide film surface formed on the silicon oxide film wafer surface is taken as a sliding surface, and the amount of wear of this silicon oxide film is shown.

  Table 3 also shows a conventional slurry used for metal CMP, in which alumina particles are dispersed in a hydrogen peroxide-based abrasive liquid having a pH value adjusted to 3. Is a table showing the wear amount of the polishing pad processing substrate per polishing pad adjustment in each wafer when the polishing pad adjustment for 1 minute is performed 100 times per time.

In Table 3, three types of wafers, a tungsten film-formed wafer in which a tungsten film is formed on a silicon oxide film wafer (conventional example), a sintered SiC wafer, and a CVD-SiC wafer, are used, and the polishing pad is used under the above conditions. The amount of wear (wear depth) of the polishing pad processing substrate when the adjustment is performed is shown.
For the silicon tungsten film wafer, the wear amount of the silicon tungsten film is shown with the tungsten film surface formed on the silicon wafer surface as the sliding surface.
Also in Table 2, as in Table 1, the CVD-SiC wafer shows two cases of the Si surface as a sliding surface and the C surface as a sliding surface, respectively. .

In any of Tables 2 and 3, when the polishing pad is adjusted using a sintered SiC wafer or a CVD-SiC wafer, the amount of abrasion of the polishing pad-treated substrate is conventionally the surface state of the polishing pad. The amount of wear of the polishing pad processing substrate when using a pre-polishing wafer (a silicon oxide film wafer in Table 1 and a tungsten film-forming wafer in Table 2) that has been used for the adjustment of the polishing pad is much smaller. ing.
In both of the oxide film CMP and the metal CMP, when the polishing pad surface treatment is performed using the sintered SiC wafer or the CVD-SiC wafer, the wear amount of the polishing pad processing substrate is very small, and the same SiC wafer is used. Can be used repeatedly as a polishing pad-treated wafer.

Moreover, it can be confirmed that the wear amount of the CVD-SiC wafer is smaller in both Table 2 and Table 3 than in the sintered SiC wafer. In addition, regarding the CVD-SiC wafer, it can be confirmed that the amount of wear of the polishing pad-treated substrate is larger when the C surface is the sliding surface than when the Si surface is the sliding surface.
In polishing pad adjustment, whether to use a sintered SiC wafer or a CVD-SiC wafer, and when using a CVD-SiC wafer, whether the sliding surface is the Si surface or the C surface The selection may be made by comprehensively judging the matching with the polishing conditions of the wafer to be polished and the wear resistance required for the polishing pad processing substrate.

As described above, the high-purity SiC wafer exhibits excellent wear resistance in adjusting the polishing pad. Furthermore, the surface of the SiC wafer is hydrophilic. For this reason, one SiC wafer can be repeatedly used for polishing pad adjustment, and processing such as forming a silicon oxide film on the surface for adjusting the polishing pad is unnecessary.
For example, when a SiC wafer is used for polishing pad adjustment in an oxide film CMP process, compared to a case where a conventionally used silicon oxide film wafer is used as a polishing pad processing substrate (that is, as a preliminary polishing substrate). Thus, the number of times that a single polishing pad processing substrate can be used repeatedly is greatly increased, and the running cost in adjusting the polishing pad can be reduced.
In addition, it is not necessary to form a silicon oxide film for adjusting the polishing pad, and it is necessary to form a silicon oxide film, which is necessary when a conventionally used silicon oxide film wafer is used as a preliminary polishing substrate. There is no such cost.
As described above, by using the SiC wafer as the polishing pad processing substrate, it is possible to reduce the cost for adjusting the polishing pad in the CMP process.

FIG. 8 shows a silicon oxide film when the silicon oxide film on the surface of the silicon oxide film wafer is polished (oxide film CMP) using a silicon oxide film wafer having a wafer diameter of 8 inches as a wafer to be polished after the polishing pad adjustment. Is a graph showing the in-plane distribution of the polishing rate, and shows the ratio of the polishing rate of each part of the wafer when the polishing rate at the center of the wafer is 1.
In FIG. 8, after adjusting the polishing pad using a polytype 3C SiC wafer (CVD-SiC wafer) having a wafer diameter of 8 inches manufactured by the above-described CVD method as a polishing pad processing substrate, an oxide film CMP is formed. A graph of the in-plane distribution of the polishing rate at the time of execution, and the polishing rate at the time of performing the oxide film CMP after adjusting the polishing pad using the silicon oxide film wafer (wafer diameter 8 inches) as a preliminary polishing substrate In-plane distribution graphs are shown.

  As shown in FIG. 8, both when the polishing pad adjustment is performed using the CVD-SiC wafer and when the polishing pad adjustment (preliminary polishing) is performed using the silicon oxide film wafer as the preliminary polishing substrate, the silicon oxide film is used. The in-plane distributions of the polishing rates are approximately the same.

Further, the total reflection fluorescent X-ray analysis was performed on the silicon oxide film wafer surface on which the oxide film CMP was performed after the polishing pad was adjusted using the above-described CVD-SiC wafer, and Fe, Cu, Ni, Cr, Na, Residual amounts of various metal impurities such as K, Ca, Al, and Ti were measured.
As a result, for any metal, the residual amount on the silicon oxide film wafer surface was less than 1 × E ¹⁰ (atoms / cm ² ). As described above, when the polishing pad is adjusted using a high-purity CVD-SiC wafer, impurities are not attached to the surface of the polished wafer in subsequent polishing.

In addition, after adjusting the polishing pad using the above-mentioned CVD-SiC wafer, a known particle counter is used for the polished silicon oxide film wafer surface when polishing the polished wafer (oxide film CMP). The presence or absence of particles and the occurrence of scratches were inspected. As a result, the number of particles is sufficiently small, 30 or less per wafer. Further, it was confirmed that scratch scratches were sufficiently small, 30 or less per wafer.
From these results, it was confirmed that a high-purity SiC wafer was suitable as a polishing pad adjustment substrate used for polishing pad adjustment in polishing of oxide film CMP or the like.

  Although the SiC substrate for polishing pad processing of the present invention has been described above, the SiC substrate for polishing pad processing of the present invention is not limited to the above-described embodiments, and various improvements can be made without departing from the gist of the present invention. Of course, changes may be made.

It is a schematic perspective view explaining the chemical mechanical polishing apparatus which adjusts a polishing pad surface state using the SiC substrate for processing a polishing pad of the present invention. (A) And (b) is a flowchart figure of an example of the grinding | polishing method of the to-be-polished wafer respectively performed with the chemical mechanical polishing apparatus shown in FIG. It is a schematic sectional drawing explaining the grinding | polishing of the to-be-polished wafer performed with the chemical mechanical polishing apparatus shown in FIG. It is a schematic sectional drawing explaining the polishing pad adjustment performed with the chemical mechanical polishing apparatus shown in FIG. It is a flowchart figure of an example of the manufacturing method of the SiC substrate for polishing pad processing of this invention. (A)-(d) is a figure explaining the outline of the preparation methods of an example of the SiC substrate for polishing pad processing of this invention shown with the flowchart in FIG. It is a figure explaining the outline of the crystal structure of an example of the SiC substrate produced by the flowchart shown in FIG. Graph of in-plane distribution of polishing rate in oxide film CMP after performing polishing pad adjustment using SiC substrate for polishing pad processing of the present invention, and polishing in oxide film CMP after performing conventional polishing pad adjustment It is a figure which shows the graph of the in-plane distribution of speed, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Wafer 14 SiC wafer 20 Polishing head part 22 Polishing pad 24 Surface plate 26 Surface plate rotation mechanism 30 Platen part 32 Wafer holding mechanism 34 Wafer pressurization / drive mechanism 40 Slurry control part 42 Dripping nozzle 44 Slurry supply means 46 Slurry 47 Abrasive fluid 49 Abrasive grain 48 Hose 50 Dresser drive unit 52 Support shaft 54 Rod 56 Dresser 58 Dresser drive means 60 Disc-shaped graphite base material 62 3C-SiC crystal 70 SiC base

Claims (5)

When polishing a desired substrate using a polishing pad, it is a dedicated substrate that slides against the polishing pad in advance to adjust the surface state of the polishing pad,
A SiC substrate for polishing pad processing, wherein a mass fraction of an element different from any of Si, C, and O is less than 1.0 (% by mass). When polishing a desired substrate using a polishing pad, it is a dedicated substrate that slides against the polishing pad in advance to adjust the surface state of the polishing pad,
A SiC substrate for polishing pad processing, wherein a mass fraction of an element different from any of Si, C, and O is less than 1.0 (mass ppm). The SiC substrate for polishing pad processing according to claim 1 or 2, wherein the density is 2.9 (g / cm ³ ) or more.   The SiC substrate for polishing pad processing according to any one of claims 1 to 3, wherein the substrate is made of SiC crystal grown by a CVD method.   5. The SiC substrate for polishing pad processing according to claim 4, wherein the SiC substrate is made of a crystal crystal of crystal system 3C and has a (111) -oriented surface.

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