JP4722006B2 - Sample holder - Google Patents

Description

  The present invention provides a polishing process, an inspection process, a transfer process, and the like for each sample such as a silicon wafer and a glass substrate in each manufacturing process such as a silicon wafer used for manufacturing a semiconductor integrated circuit and a glass substrate used for manufacturing a liquid crystal display device. The present invention relates to a sample holder that holds a sample when processing is performed.

Samples of semiconductor wafers made of silicon or other materials used in the manufacture of semiconductor integrated circuits and glass substrates used in the manufacture of liquid crystal display devices are held multiple times on the sample stage of manufacturing equipment or inspection equipment during the manufacturing process. Is done. As a method of holding a sample on a sample stage, various apparatuses and holding methods have been proposed depending on the type of manufacturing process. The step of holding the sample is, for example, a step of polishing the sample to a mirror surface without scratches, a step of partially exposing a photosensitive material called a resist coated on the sample with light having a uniform wavelength or an electron beam, There are a process for removing the exposed resist and a process for inspecting a sample after each process. In addition to the atmosphere around the sample stage holding the sample, in addition to a special gas (gas) atmosphere such as nitrogen or oxygen, the pressure is 1 × 10 ⁵ Pa, which is atmospheric pressure, and 1 × 10 called high vacuum. ^Wide range of ^-7 Pa.

  Conventional sample holders use materials with high corrosion resistance corresponding to these various processes and atmospheres, and use mechanical force such as a spring, differential pressure, or electrostatic force as a means to hold the sample. Sample adsorbers have been used.

  Recently, along with further miniaturization and higher density of semiconductor integrated circuits, adhesion of particles generated by frictional wear between the sample and the sample holder when holding the sample, the surface of the sample holder Various problems have been recognized, for example, particles that have entered a scratch on the surface of the sample are reattached to the sample sporadically due to external forces such as vibration.

  To solve this problem, a method of reducing the contact area between the sample and the sample holder, a method of reducing frictional wear by smoothing the contact portion, a method of curving the contact portion with the sample, A method of polishing the surface using abrasive grains or ultrasonic waves has been used.

  In Patent Document 1, when the sample is detached from the sample holder using a lift pin or the like by mirror polishing the top surface and the side surface of the pin of the sample holder, the top surface and the side surface of the pin It has been proposed that even if a contact occurs, the contact is smooth and the friction coefficient is reduced, so that generation of particles can be prevented. The surface roughness Ra of the top and side surfaces of the pin is preferably 0.25S.

  Patent Document 2 proposes that after forming a pin having a flat top surface, the periphery of the top surface of the pin is rounded and smoothly curved. According to this proposal, it is possible to remove burrs at the micron level by forming the edge of the pin into a rounded smooth curved surface, and particles reattach to the pin when wiping the sample holder. It is said that this can be reduced. It is said that round processing is preferable for processing the edge of the pin.

  In Patent Document 3, as a means for reducing the contact ratio between the sample and the pin in order to reduce the generation of particles due to the contact between the sample and the pin, the pin is formed in a truncated cone shape, a truncated pyramid shape, and cylinders having different diameters stacked. It has been proposed that According to this proposal, the rigidity of the pin can be kept high, the flatness of the sample placed on the pin can be kept highly accurate, and the contact ratio between the sample and the pin can be reduced. It is said that the generation of particles can be reduced.

  Among the manufacturing processes of a sample such as a semiconductor wafer used for manufacturing a semiconductor integrated circuit and a glass substrate used for manufacturing a liquid crystal display device, the exposure apparatus used in the exposure process for exposing the sample is described above. The sample holder is used to hold the sample, and a predetermined pattern is transferred to the sample via the projection optical system.

Patent Document 4 discloses a method of performing exposure through water between a projection optical system and a sample surface, that is, a liquid immersion method. The sample holder used in these exposure apparatuses is composed of a disk-shaped substrate having a plurality of pins for holding the sample on its upper surface, and a Z tilt stage is joined to the lower part of the substrate of the sample holder. The Z tilt stage is provided with an annular member different from the base, and the upper surface of the annular member is formed to be flush with the upper surface of the pin in the sample holder. Thereby, a flow path is formed by the outer peripheral side surface of the base of the sample holder, the Z tilt stage and the annular member, and acts as a flow path for collecting water used during exposure.
JP 2003-86664 A JP-A-9-283605 Japanese Patent Laid-Open No. 10-242255 JP 2005-310933 A

  When placing a sample on the sample holder, local swell of the sample may occur due to particles being sandwiched between the back surface of the sample and the pin. For example, in the case where exposure is performed, for example, when the exposure is performed, the focus of the exposure is lost, the exposure pattern is blurred, and a semiconductor defect such as a short circuit of a circuit pattern formed on the sample occurs. In order to reduce the yield reduction due to this semiconductor defect, the sample holder is cleaned so that particles brought in from outside do not remain on the front and back of the sample.

  In particular, with the recent increase in the area of the sample, the area of the sample holder has also increased, and it has become difficult to clean the sample holder with a washing tank. The work of cleaning by wiping is often used.

  In Patent Documents 1 and 2, although the cause of the particles is different, the countermeasure against the particles is to reduce the particles generated from the pins by smoothly processing the top surface, side surface, or peripheral portion of the top surface of the pins. It is common.

  However, when the pins are formed of ceramics, the ceramics are polycrystalline and it is very difficult to completely remove the voids present at the triple points of the crystal. Therefore, as described above, there is a problem that even if the top surface and the side surface of the pin are mirror-finished, voids are present, so that particles intervening in the voids sporadically reattach to the sample due to external forces such as vibration.

  When the wiping cloth wipes the top surface of the pin when wiping with the wiping cloth, if the wiping cloth touches the edge of the pin, the particles adhering to the wiping cloth are scraped off, and the scraped particles are applied to the pin. There were problems such as reattachment.

  As in Patent Document 3, even if the pin has a tapered shape such as a truncated cone or a truncated pyramid, the tip of the pin has an edge shape, which not only scrapes and reattaches particles adhering to the wiping cloth. There is a problem in that the fibers of the wiping cloth are sheared to newly generate particles.

  When wiping off particles accumulated on the upper surface of a cylinder, the wiping cloth fibers are cut at the edge of each cylinder, and the wiping cloth itself causes particle generation. There was a problem.

  In addition, when the sample holder is used in the exposure process, in Patent Document 4, the flow path is not formed on the base, but is formed by the outer peripheral side surface of the base, the Z tilt stage, and the annular member. For this reason, the flat surfaces of the members are continuous at right angles, and the used water tends to remain in the corners and is difficult to recover quickly. The water that could not be collected adsorbs surrounding particles (such as dust floating in the air), the water comes into contact with the sample, and the water further dries so that the sample contains particles called watermarks. There was a problem of causing contamination. In addition, since a part of the flow path is formed by using the outer peripheral side surface of the base, the depth of the flow path is determined by the thickness of the base, so that it takes a long time to recover the water, There was also a risk that the water was dried on the sample holder before and a watermark was generated.

In view of the above problem, the sample holder of the present invention has the following configuration.

The sample holder of the present invention includes a plurality of pins for holding a sample on one main surface of a ceramic substrate, and a seal for closing a space between the plurality of pins arranged and held around the plurality of pins. At least one groove that opens toward one main surface of the ceramic substrate and circulates around the outside of the plurality of pins, and is tapered toward the bottom, and at the bottom of the groove A sample holder having a suction hole that opens so as to communicate with each other, wherein the pin is tapered toward the tip and includes at least one shoulder portion including a plurality of inclined surfaces over the outer periphery thereof. It is characterized by that.

The sample holder of the present invention is characterized in that the shoulder portion has a curved surface portion whose inclined surface is convex outward and a curved surface portion convex toward the inside .

  The sample holder of the present invention is characterized in that a boundary portion between the opening of the groove and one main surface of the ceramic substrate is a curved surface.

  The sample holder of the present invention is characterized in that the groove is arranged so as to go around the outside of the seal portion.

  The sample holder of the present invention is characterized in that the ceramic substrate is made of a silicon carbide sintered body.

  According to the sample holder of the present invention, the pin arranged on one main surface of the ceramic base is tapered toward the tip, and at least one shoulder portion formed of a plurality of inclined surfaces is provided on the outer periphery thereof. Because it is equipped with, even after scraping off excessive particles adhering to the wiping cloth, wiping with the wiping cloth on the inclined surface and the top surface is not performed at the same time, so it is possible to prevent the particles from reattaching to the pin At the same time, the wiping operation can be shortened.

  According to the sample holder of the present invention, the contact between the sample and the shoulder portion can be reduced, and the generation of scratches on the sample or the generation of particles from the pins can be reduced.

  According to the sample holder of the present invention, since the shoulder portion has a curved surface portion that is convex outward and a curved surface portion that protrudes inward, the wiping cloth is smooth. Since wiping is performed, the fibers of the wiping cloth can be prevented from being broken, and the wiping cloth itself can be prevented from causing particles.

  According to the sample holder of the present invention, at least one groove that opens toward one main surface of the ceramic base and is arranged so as to go around the outside of the plurality of pins, and is tapered toward the bottom, and the groove And a suction hole that opens to communicate with the bottom of the sample, so that when water is used during the exposure process, water that leaks from the top surface of the sample is quickly and sufficiently collected by the tapered groove. Can be efficiently recovered. As a result, there is almost no adhesion of particles to the sample due to water remaining.

  According to the sample holder of the present invention, the opening of the groove has a curved surface boundary with one main surface of the ceramic substrate. Therefore, there is almost no scattering of water to the outside of the groove, and water can be recovered more efficiently.

  According to the sample holder of the present invention, since the groove is arranged so as to go around the outside of the seal portion, even if water leaks from any part on the outer peripheral side of the sample such as a semiconductor wafer, It can be recovered without splashing water.

  According to the sample holder of the present invention, since the ceramic base is made of a silicon carbide sintered body, the wettability between the base and water is increased, and the sample holder is provided in the sample adsorption device using the sample holder. Even if it moves at high speed, it can be held by the substrate without splashing water, so that leakage of water to peripheral devices such as a stage can be prevented.

  Hereinafter, the sample holder of the present invention will be described.

  FIG. 1 is a drawing showing an embodiment of a sample holder of the present invention, FIG. 1 (a) is a perspective view in which a part of the sample holder is broken, and FIG. 1 (b) is A in FIG. It is the expansion perspective view and sectional drawing of a part. 2A to 2C are cross-sectional views showing various examples of pins in the sample holder of the present invention.

  As shown in FIG. 1, a sample holder 100 of the present invention is disposed on and held around a plurality of pins 1 for holding a sample and a plurality of pins 1 on one main surface of a ceramic substrate 3. And a seal portion 2 for sealing between the sample and the sample.

  As shown in FIGS. 2A to 2C, the pin 1 is tapered toward the tip, and includes at least one shoulder portion 4 including a plurality of inclined surfaces 6 over the outer periphery of the pin 1. It has a shoulder portion 4 and a top surface 5 continuously from the side surface 7 of the pin 1. The plurality of pins 1 are preferably arranged concentrically from the center of the main surface of the ceramic substrate 3.

  The shoulder portion 4 provided on the pin 1 refers to a range extending from the peripheral portion 5a of the top surface 5 of the pin 1 to the peripheral portion 7a above the side surface 7 of the pin 1, and is surrounded by a dotted line in FIGS. And is formed continuously by a plurality of inclined surfaces 6.

  Here, FIGS. 3A and 3B are conceptual diagrams when the wiping operation is performed on the sample holder 100 using a wiping cloth.

  The sample holder 100 is provided with a plurality of pins 1, and the amount of particles adhering to the wiping cloth 20 increases as the wiping operation progresses. As shown in 3 (a), the wiping cloth 20 first contacts the peripheral edge portion 7a of the side surface 7 of the shoulder portion 4 of the pin 1 to scrape particles adhering to the wiping cloth 20 at this portion. Since the inclined surface 6 and the top surface 5 are wiped off, it is possible to prevent particles from reattaching to the top surface 5. On the other hand, in the case of the conventional pin 21 without the shoulder portion 4, as shown in FIG. 3B, the wiping cloth 20 first abuts directly on the top surface 15 of the pin 21 or the peripheral portion 15a of the top surface 15. Therefore, scraping of particles excessively attached to the wiping cloth 20 and wiping of the top surface 15 are performed almost simultaneously, so that the particles are easily reattached on the top surface 15.

  Since the shoulder portion 4 of the pin 1 is composed of a plurality of inclined surfaces 6, even if the sample is stressed due to chucking or adsorption stress during sample transport, and the sample is deformed such as bending, the sample and shoulder It becomes possible to reduce the contact with the part 4, and it is possible to reduce the generation of scratches on the sample and the generation of particles from the pin 1. Even if particles accumulate on the shoulder portion 4, the distance from the sample can be maintained, so that it is possible to prevent the particles from adhering to the sample.

  The angle θ formed by each inclined surface 6 of the shoulder portion 4 is preferably 90 degrees or more. This is because, when the angle θ is less than 90 degrees, when the sample holder 100 is wiped with the wiping cloth 20, particles easily enter the boundary portions of the inclined surfaces 6 and it is difficult to wipe the particles that have entered. This is because setting the angle θ to 90 degrees or more facilitates wiping of particles and shortens the wiping operation. Furthermore, the angle θ is preferably set to 120 degrees or more.

  As shown in the cross-sectional view of the pin 1 in FIG. 4, the shoulder portion 4 preferably has a curved surface portion 6 a whose inclined surface 6 is convex outward and a curved surface portion 6 b that is convex inward. .

  An outwardly convex curved surface portion 6 a is an inclined surface 6 that is continuous with the side surface 7 of the pin 1, and an inwardly convex curved portion 6 b is the surface of the inclined surface 6 that is continuous from the top surface 5. That means. If the pin 1 has a curved surface portion 6a that protrudes outward, even if the wiping cloth 20 comes into contact with this portion in the wiping operation, the wiping cloth 20 is wiped off smoothly. Can be prevented, and the wiping cloth 20 itself can be prevented from generating particles. At the same time, having the curved surface portion 6b that protrudes inward can facilitate wiping off the particles present on the inclined surface 6 and prevent particles from remaining, thereby shortening the wiping operation. be able to.

  In order to reduce the generation of particles or the generation of scratches on the sample, it is required to make the contact area between the sample and the top surface 5 of the pin 1 as small as possible, but the inclined surface 6 is inward as described above. By having the curved surface portion 6b that protrudes toward the surface, it is possible to maintain the mechanical strength of the pin 1, particularly the rigidity of the portion immediately below that contacts the sample, and the pin 1 when the sample is placed on the pin 1 Therefore, the flatness of the sample can be accurately maintained and the area of the top surface 5 can be reduced. Further, since the curved surface portion 6a is convex outward, even if the sample comes into contact with the inclined surface 6 due to the bending of the sample placed on the pin 1, it is possible to reduce the occurrence of scratches on the sample. In addition, generation of particles due to contact can be reduced.

  Here, the outwardly convex curved surface portion 6a and the inwardly convex curved surface portion 6b may be formed continuously in the inclined surface 6, and a straight line between the curved surface portions 6a and 6b. The inclined surface 6 which consists of a part may be formed.

  In FIG. 1, the pins 1 are arranged in a plurality of rows on one main surface of the ceramic substrate 3, but are more preferably arranged radially from the center of the ceramic substrate 3, so that the sample can be more stable. Can be held.

  As shown in FIG. 1, the sample holder 100 of the present invention includes a seal portion 2 for closing the space between the sample held on the outer peripheral portion of the region including the plurality of pins 1.

  As shown in the cross-sectional views of FIGS. 5A to 5C, the seal portion 2 includes at least a shoulder portion 24 formed of a plurality of inclined surfaces 26 over the outer periphery 27a side and the inner periphery 27b side of the seal portion 2, respectively. It is preferable to provide one.

  In particular, as shown in FIG. 5B, the shoulder portion 24 is connected by a curved surface portion 26 a having an inclined surface 26 that protrudes outward from the seal portion 2 and a curved surface portion 26 b that protrudes inward. It is preferable.

  The effects in these embodiments are the same as those described for the pin 1 described above, and the wiping operation can be facilitated and the wiping operation can be shortened. In particular, on the inner periphery 27 side of the seal portion 2, there is a high probability that the end portion of the sample comes into contact with the shoulder portion 24b when the sample is placed or detached, but the curved portion 26a that protrudes outward from the shoulder portion 24b. Since the sample slips with respect to the inclined surface 26b by being connected to the inwardly convex curved surface portion 26b, generation of particles or generation of scratches on the sample can be reduced.

  Next, another embodiment of the sample holder of the present invention will be described with reference to FIG.

  FIG. 6 is a view showing another embodiment of the sample holder 200 of the present invention. FIG. 6A is a perspective view in which a part of the sample holder is broken, and FIG. FIG. 4A is an enlarged perspective view and a sectional view of part B in FIG.

  Similar to the above-described embodiment, the sample holder 200 is arranged and held around the ceramic base 3, the plurality of pins 1 that hold the sample on one main surface of the ceramic base 3, and the plurality of pins 1. And a seal portion 2 for sealing between the sample and the sample to be measured. Further, the seal portion 2 is opened at one main surface of the ceramic base 3 and is arranged so as to go around the outside of the plurality of pins 1. At least one groove 9 that is tapered toward the bottom, and a suction hole 8 that opens to communicate with the bottom of the groove 9 are provided.

  As shown in FIG. 6, a sample such as a semiconductor wafer is formed by providing a groove 9 and a suction hole 8 so as to open on one main surface of the ceramic substrate 3, that is, the main surface on which the pins 1 and the seal portion 2 are formed. It is effective as a sample holder used in the liquid immersion exposure process. In the immersion exposure process, exposure is performed between the projection optical system and the sample surface via a liquid such as water. The groove 9 and the suction hole 8 function to collect used liquid such as water, and efficiently collect the water leaked from the retained sample by the groove 9, and a vacuum pump (not The suction can be removed by connecting a suction means such as the one shown in the figure. A plurality of suction holes 8 are formed so as to open at intervals at the bottom of the groove 9 as shown in FIG.

  Since the shape of the groove 9 is tapered toward the bottom, the leaked water can be captured efficiently, and the recovery rate can be increased toward the bottom of the groove 9. As a result, it is possible to efficiently recover the liquid from the suction hole 8 and to eliminate the problem of contamination including particles called a watermark that occurs when the remaining water is adsorbed to the sample and dried.

  The shape of the groove 9 is preferably such that the angle θ shown in FIG. 6B is 50 to 85 degrees, and more preferably 60 to 70 degrees, thereby further improving the recovery rate of liquid such as water. it can. Further, the bottom of the groove 9 is preferably curved as shown in FIG. 6 (b), so as to eliminate the possibility that water remains trapped at the bottom of the groove 9 at a position away from the suction hole 8. Because you can.

Similar to the above, the water recovery efficiency can be further improved.

  As shown in FIG. 6A, the groove 9 is arranged from the center of the sample holder 200 to the center in the radial direction so as to go around the outside of the predetermined pin 1 among the plurality of pins 1. . This is because the leaked liquid can be quickly recovered even if the sample is moved while being held in the sample holder 200 during the immersion exposure process. Further, it is more preferable that the seal portion 2 is arranged so as to circulate around the outer periphery of the seal portion 2. Even if water leaks from any portion on the outer periphery side of the sample, the water can be recovered without being scattered. In the sample holder 200 shown in FIG. 6A, two seal portions 2 are provided, and the seal portion 2 provided in the central portion in the radial direction of the sample holder 200 is connected to the sample to be held. It acts to close the gap. The seal portion 2 provided on the outer peripheral portion in the radial direction of the sample holder 200 is for holding an annular flat plate jig for positioning the held sample with high accuracy. High-accuracy positioning is performed by placing the sample to be held in a circular gap provided in the flat plate jig. In this case, the groove 8 having the suction hole 8 circulates around the seal portion 2 provided in the central portion of the sample holder 200 in the radial direction, as well as a seal provided in the outer peripheral portion of the sample holder 200 in the radial direction. You may arrange | position so that the part 2 may circulate.

As shown in FIGS. 6B and 6C, the groove 9 preferably has a curved boundary portion 10 between the opening of the groove 9 and one main surface of the ceramic substrate 3. This makes it possible to capture the leaked water more efficiently with the curved surface of the boundary portion 10, particularly prevent the water from splashing outside the groove 9, and efficiently collect the water from the suction hole 8. . Further, the boundary portion 10 between the opening of the groove 9 and one main surface of the ceramic substrate 3 forms a curved step, so that the leaked liquid is temporarily stored in the step of the boundary portion 10 and sucked. Since it becomes easy to apply a negative pressure from the hole 8 into the groove 9, the liquid attached to the seal portion 2 can be easily collected. The sample holders 100 and 200 of the present invention are mainly composed of silicon carbide, alumina, silicon nitride, or the like. In particular, it is preferably made of a silicon carbide sintered body. Since the silicon carbide sintered body can have a thermal conductivity of 180 W / (m · K) or more at room temperature, it has excellent heat dissipation even when heat is locally applied to the sample. Therefore, it is possible to reduce the deterioration of accuracy due to the heat generated during exposure in semiconductor manufacturing. The thermal conductivity at room temperature is a value measured with the measurement temperature in the range of 22 ° C. to 24 ° C., and the thermal conductivity measured at any set temperature within this temperature range is 180 W / (m -K) Indicates that it is greater than Furthermore, even in an environment exceeding the room temperature, the thermal conductivity can be maintained at a high value, and for example, the thermal conductivity of 60 W / (m · K) or more can be maintained even in applications at 600 ° C. or higher.

  When the sample holder is used in a process using water, the silicon carbide sintered body has high wettability with water, and the stage of the sample adsorbing device moves at a high speed with the sample holder 100 or 200 mounted. This is because the leaked water can be prevented from leaking to the peripheral device such as the stage without leaving the sample holder 100 or 200.

  The silicon carbide sintered body preferably has an average crystal grain size in the range of 3 to 10 μm. The reason is that if it is less than 3 μm, the crystal particles in the silicon carbide sintered body are not sufficiently filled, and the mechanical properties of the sintered body are impaired. In particular, since the strength and rigidity are low, the rigidity of the pin 1 is insufficient, and the flatness of the placed sample cannot be accurately maintained. In addition, if the average crystal grain size is larger than 10 μm, voids existing between the crystals may remain without being crushed, so that the particles enter the voids, thereby reducing the efficiency of the wiping operation. At the same time, the remaining particles adhere to the sample and cause yield. Therefore, the average crystal grain size is preferably in the range of 3 to 10 μm, and more preferably in the range of 3 to 7 μm.

The silicon carbide sintered body preferably has a density of 3.18 g / cm ³ or more, a Young's modulus of 440 GPa or more, and a specific rigidity of 135 GPa · cm ³ / g or more, and is placed on the top surface 5 of the pin 1. It becomes possible to maintain the flatness of the obtained sample with high accuracy. In addition, it is important that the linear expansion coefficient is 2.6 × 10 ⁻⁶ / ° C. or less at room temperature no matter how high the thermal conductivity is. It becomes. In addition, since the average void diameter is 1.5 μm or less and the maximum void diameter is 5 μm or less, even if the member is in direct contact with the sample, the void is small and the generation of particles generated between silicon carbide crystals is suppressed. be able to.

  Next, a manufacturing method for obtaining the above-described sample holders 100 and 200 will be described.

  First, a raw material powder obtained by adding at least a boron compound powder and a carbon compound powder as additives to silicon carbide powder as a main component is obtained. Next, the raw material powder is molded using various molding methods to obtain a molded body, and then the primary sintering is completed at a temperature at which silicon carbide particles are suppressed from growing, and primary sintering is performed. After obtaining the body, hot isostatic pressing (HIP) treatment is performed.

This will be described in more detail below. Silicon carbide powder as the main component, boron carbide (B ₄ C), metal boron, etc. as boron compounds that form boron components as additives, carbon compounds that form carbon components, such as carbon black, graphite, etc. A phenol resin or coal tar pitch that can generate carbon can be used. The content of these additives depends on the amount of oxygen in the raw material powder, and it is necessary that 0.15 to 3 mol of boron and 1 to 5 mol of carbon remain with respect to 1 mol of oxygen in the silicon carbide raw material. It is.

  These raw material powders are weighed at a predetermined ratio and mixed thoroughly by a mixing means such as a ball mill, and then a binder is added to the powder, and a known molding method such as press molding, extrusion molding, casting molding, cold A molded body is obtained by molding into a desired shape by isostatic pressing or the like. In addition, when phenol resin etc. are added as an additive, carbon can be produced | generated by carrying out the calcination process in 600-800 degreeC in a non-oxidizing atmosphere, and thermally decomposing.

  Next, in order to obtain high thermal conductivity, the sintered body obtained as described above is subjected to primary sintering at a relatively low temperature of 1900 to 2100 ° C. in a vacuum or in an inert atmosphere such as Ar. As a result, since the grain growth can be suppressed without increasing the activity by reducing the amount of heat at the time of primary sintering, it is possible to suppress the grain growth of the silicon carbide particles of the molded body, and the voids existing between the crystals are also small. can do. When the primary sintering temperature is lower than 1900 ° C., the crystal does not sinter, and it becomes difficult to eliminate sufficient voids no matter how much the HIP treatment is performed thereafter. On the other hand, when the temperature is higher than 2100 ° C., the crystals of the primary sintered body will be enlarged, so that when the HIP treatment is further performed, the crystals of the silicon carbide-based sintered body that are obtained no matter how low the temperature are processed. Large, void disappearance becomes difficult. Furthermore, if the crystals are not sufficiently sintered, the bonding of the particles will be insufficient, and if this silicon carbide sintered body is used for a substrate holding disk, the grains will be shattered during blasting during the formation of protrusions. It is easy to cause chipping. In addition, when the crystal is enlarged, a defective portion is generated at a time when one crystal is grain-removed, which is not preferable at the time of blasting when forming a protrusion.

  Finally, the obtained primary sintered body is subjected to HIP treatment. As a result, voids having a void diameter exceeding 5 μm can be almost eliminated while maintaining the size of the silicon carbide crystal substantially the same as the size at the end of the primary sintering. In addition, it becomes possible to control the solid solution of an additive composed of a compound of boron or carbon or a cation in the additive into silicon carbide, and the grain growth of silicon carbide particles can be effectively suppressed.

  In the firing step, primary sintering is performed in a vacuum atmosphere at a temperature of 1900 to 2100 ° C., and HIP treatment is performed in an inert gas atmosphere at a temperature of 1800 to 2000 ° C. and 180 MPa or higher to obtain a silicon carbide-based sintered material. The average void diameter of the body can be 1.5 μm or less, and the maximum void diameter can be 5 μm or less. When used as a substrate holder or a sample holder 100 as a member of a semiconductor or liquid crystal manufacturing apparatus, silicon carbide Generation of particles generated between crystals can be suppressed. When the temperature of the HIP process is lower than 1800 ° C., the densification is not promoted because the temperature is lower than the temperature at which the primary sintered body is formed. Furthermore, it is preferable to set the temperature of HIP treatment at a temperature lower than 100 ° C. below the temperature of primary sintering, and if this temperature range is reached, the pressure can be increased when the crystal is softened. Easily disappear. On the other hand, when the temperature is higher than 2000 ° C., the temperature range is higher than the temperature of primary sintering, so that the growth of crystals is promoted and voids hardly disappear. Tends to be low. At the same time, by setting the inert gas atmosphere to 180 MPa or more, voids existing between the silicon carbide particles are crushed, and the voids are more likely to disappear.

  More preferably, the primary sintering temperature is fired in a vacuum atmosphere of 1950 to 2050 ° C., and the HIP treatment temperature is 1850 to 1950 ° C. and an inert gas atmosphere of 190 MPa or more.

Further, as additives, TiC, TiN, a compound of titanium such as TiO ₂ 200ppm or more in terms of titanium, and is preferably added in the range 400 ppm. If it is less than 200 ppm, the thermal conductivity of the obtained sintered body is 180 W / (m · K) or higher, and the thermal conductivity at 600 to 800 ° C. cannot be 60 W / (m · K) or higher. If it exceeds 400 ppm, these metal compounds are liable to be dissolved in silicon carbide crystals, and the strength and rigidity of the silicon carbide based sintered body are deteriorated. Moreover, it becomes easy to produce | generate a boron and compound which are other sintering auxiliary agents, and sinterability will be inhibited, and influences, such as a density not going up, will come out.

  The ceramic body 3 is manufactured by processing the HIP-processed sintered body. The pin 1 and the seal portion 2 can be formed by forming a pin and a seal portion by a method such as etching and then processing the surface by a method using the wiping cloth described above.

  In the method of manufacturing the sample holder 200 having the groove 9 as shown in FIG. 6, the pin 1 and the seal portion 2 are formed on the ceramic substrate 3 by the manufacturing method described above. Next, the surface of the ceramic substrate 3 other than the portion where the groove 9 is to be formed is masked and protected with a hard member.

  As a method of forming the groove 9 and the suction hole 8, the sample holder 100 is manufactured and then viewed from the center of the ceramic substrate 3 by a so-called blasting process in which fine ceramic abrasive grains are sprayed onto the ceramic substrate 3 at high speed from the tip of a thin nozzle. The groove 9 is formed while moving the nozzle concentrically. In this case, in order to make the groove 9 tapered toward the bottom, the shellac abrasives discharged from the nozzles are separated from the both sides of the opening of the groove 9 toward the center of the bottom of the groove 9, respectively. It is preferable to perform the blasting process while maintaining the direction in which the ceramic abrasive grains are sprayed so as to be sprayed. More preferably, after the blasting process, the inner surface of the groove 9 has irregularities, and then the inside of the groove 9 is polished by attaching a fine diamond paste to the wiping cloth. Thereby, the surface roughness of the surface of the groove 9 is reduced, the resistance of the water flowing in the groove 9 is reduced, and a liquid such as water can be quickly collected in the suction hole 8.

  Finally, the sample holder 200 can be obtained by drilling the suction holes 8 at predetermined positions, for example, at regular intervals.

  The sample holders 100 and 200 thus manufactured include, for example, an electrode part formed on the main surface above the ceramic substrate 3 and a power supply part for applying a potential to the sample. By applying a voltage to the part and the sample, electrostatic force generated between the sample and the electrode part evacuates the sample adsorption device that holds the sample with the pin 1 and the gap between the seal part 2 and the placed sample. As a sample adsorbing device that has an evacuation means for holding the sample by a differential pressure generated between the upper and lower sides of the sample by suction force, it can be used in various processes such as polishing and photosensitivity and conveyance of the sample it can.

One Embodiment of the sample holder of this invention is shown, (a) is the perspective view which fractured | ruptured one part, (b) is the perspective view and sectional drawing which show the A section of the same figure (a). (A)-(b) is sectional drawing which shows the various shapes of the pin with which the sample holder of this invention is equipped. (A) is a conceptual diagram which shows the state of the wiping operation | work of the sample holder of this invention, (b) is the work state of the wiping off of the conventional sample holder. It is sectional drawing which shows another embodiment of the pin with which the sample holder of this invention is equipped. (A)-(c) is sectional drawing which shows various embodiment of the seal part regarding the sample holder of this invention. The other embodiment in the sample holder of this invention is shown, (a) is the perspective view and sectional drawing which show B part, (c) is sectional drawing which shows a groove | channel vicinity.

Explanation of symbols

1, 2: 1: Pin 2: Seal portion 3: Ceramic base 4, 24: Shoulder portion 5, 25: Top surface 5a: Peripheral portion 6 of top surface, 26: Inclined surface 6a, 26a: Curved surface convex outward Portions 6b and 26b: Inwardly convex curved surface portion 7: Side surface, 7a: Side edge portion 27a: Outer periphery, 27b: Inner periphery 8: Suction hole 9: Groove 10: Step 20: Wiping cloth 100, 200: Sample holder

Claims (5)

On one principal surface of the ceramic base, together comprising a plurality of pins to hold the sample, it is arranged around the pin of the plurality of, and a sealing portion for closing the space between the sample to be retained, the ceramic At least one groove that tapers toward the bottom and is arranged to circulate around the outside of the plurality of pins, and a suction hole that opens to communicate with the bottom of the groove. And the pin is tapered toward the tip, and has at least one shoulder portion formed of a plurality of inclined surfaces over the outer periphery thereof. Retaining tool.   The sample holder according to claim 1, wherein the shoulder portion includes a curved surface portion whose inclined surface is convex outward and a curved surface portion convex inward. The sample holder according to claim 1 or 2 , wherein the opening of the groove has a curved surface at a boundary with one main surface of the ceramic substrate. The sample holder according to any one of claims 1 to 3, wherein the groove is arranged so as to go around the outside of the seal portion. The sample holder according to any one of claims 1 to 4 , wherein the ceramic substrate is made of a silicon carbide sintered body.

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