JP2009056518A - Suction device, machining system having the same, and machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suction device in which the pressure loss of an outer suction body is prevented from being increased due to the intrusion or filling of foreign matters such as grinding chips and polishing chips into the pores of the outer suction body even when a body to be sucked is sucked by using only an inner suction body and the grinding and polishing of the surface thereof are repeatedly performed, and also to provide a machining system having the suction device, and a machining method. <P>SOLUTION: A vacuum chuck 1 having the suction body 2 with a suction surface 2b divided into multiple areas by a partition wall 5 of an annular shape in plan view comprises a means for filling the insides of the pores 2a of the suction body 2d with a liquid by changing the suction body 2d from a liquid discharge means to a liquid supply means. By using the vacuum chuck 1, the liquid is supplied to the suction body 2d and the pores 2a are filled with the liquid even when the body to be sucked is sucked by using only the inner suction body 2c and the grinding and polishing of the surface of the body to be sucked are repeatedly performed. The foreign matters such as grinding chips and polishing chips thereby hardly intrudes or clogs into the pores of the outer suction body 2d. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an adsorption device for adsorbing an adsorbed body such as a semiconductor wafer or a glass substrate, and a processing system and a processing method including the same.

  In the manufacturing process of a semiconductor device, a vacuum chuck that sucks and holds a semiconductor wafer for processing is used. Various devices have been studied for the structure of this vacuum chuck and the material of each member of the vacuum chuck, so that a vacuum chuck using a porous body that can reliably adsorb to a semiconductor wafer and gives a uniform adsorbing action will be used. It is becoming.

  The vacuum chuck using such a porous body gives an adsorption action to the surface of the porous body by sucking through the fine pores of the porous body, and adsorbs and holds the semiconductor wafer on the surface of the porous body. be able to.

  Such vacuum chucks and vacuum suction devices are disclosed in Patent Documents 1 and 2 described later. FIG. 7 shows an example of the vacuum chuck disclosed in Patent Document 1. FIG. 7A is a perspective view of a chuck table provided with a vacuum chuck (suction plate), and FIG. 7B is a schematic cross-sectional view of the chuck table of FIG.

  The chuck table 21 is made of a porous body having a suction surface 22a for sucking a semiconductor wafer (not shown), and is made of a ceramic that is the same as the suction section 22. The annular partition wall 25 and the annular support part 23 that surrounds and supports the adsorption part 22 are integrally fired and screwed to the upper surface of the base 24 to be attached. The base 24 is formed with a circular suction groove 26a and a concentric suction groove 26b in the center corresponding to the suction portion 22 made of a porous body, and in the suction grooves 26a and 26b. Suction holes 26c and 26d communicating with each other are formed, and these suction holes 26c and 26d communicate with a suction source (not shown) such as a vacuum pump through a ventilation path 27.

  Therefore, when a semiconductor wafer (not shown) is placed on the suction surface 22a of the suction part 22 and the suction part 22 is sucked by the suction means (not shown), the suction action is performed through the pores of the suction part 22. The semiconductor wafer can be sucked and held by reaching the suction surface 22a. In addition, various semiconductor wafers (not shown) having different diameters can be sucked and held by selectively opening and closing the valve 29 attached in the ventilation path 27. According to this vacuum chuck 21, there are no gaps or steps formed between the suction part 22 and the support part 23, and there is no restriction from the bottom part because the support part 23 has no bottom part, and the suction surface 22a is wavy. Since it does not occur, when the surface of the semiconductor wafer is ground, it is possible to prevent dents, steps and waviness and to perform grinding with high accuracy.

  FIG. 8 shows an example of a vacuum suction device (vacuum chuck) disclosed in Patent Document 2. FIG. 8A is a horizontal sectional view of the vacuum suction device (vacuum chuck), and FIG. 8B is a vertical sectional view taken along line AA of FIG.

The vacuum suction device 30 includes a disk-shaped suction portion 31, an annular suction portion 32 provided so as to surround the outer periphery of the suction portion 31, and an intermediate glass formed between the suction portion 31 and the annular suction portion 32. The semiconductor wafer W includes a portion 33 and a vessel-like support portion 34 that supports the suction portion 31 and the annular suction portion 32, and is sucked by a suction device (not shown) such as a vacuum pump through the suction hole 35. Can be adsorbed and held. The adsorbing part 31 is made of a porous body in which ceramics and first glass are combined, the intermediate glass part 33 is made of a second glass porous body, and the annular adsorbing part 32 is made of ceramics and third glass. Composed of a composite porous body, each of the first to third glasses has a different softening point, and is formed first for sequential firing in the order of the adsorption part 31, the intermediate glass part 33, and the annular adsorption part 32. The glass contained in the formed part is not softened or melted by subsequent firing, and each part is directly joined substantially without a gap. Further, in the final stage of the manufacturing process, the surface of each part is simultaneously ground and polished to prevent a step, and an adsorption surface with good flatness can be formed.
JP 2001-138228 A JP 2006-93491 A

  However, when the chuck table 21 disclosed in Patent Document 1 is used, it can be ground with high accuracy without causing depressions, steps, undulations, etc., on the surface of the semiconductor wafer. When the surface of the semiconductor wafer is adsorbed using only the portion 22 and the surface grinding and polishing are repeated, foreign matters such as grinding scraps and polishing debris enter and fill the pores of the adsorbing portion 22 on the outer peripheral side, and adsorb the outermost periphery. The pressure loss of the part 22 and the intermediate suction part 22 may be increased.

  Further, in the vacuum suction device 30 disclosed in Patent Document 2, the adjacent parts among the suction part 31, the annular suction part 32, the intermediate glass part 33, and the support part 34 are directly joined with substantially no gap. Therefore, there is little variation in the bonding strength, and the bonding strength can be increased. As a result, the surface of each part is ground and polished at the same time, and the flatness of the surface can be maintained well. As with the vacuum chuck 1, when the semiconductor wafer W is sucked using only the suction portion 31 and the surface grinding and polishing are repeated, foreign matters such as grinding dust and polishing waste enter and fill the pores of the annular suction portion 32. And the pressure loss of the adsorption | suction part 22 of the outer peripheral side may be raised.

  Also, depending on the material used for the vacuum chuck, the heat generated when the semiconductor wafer is sucked and held for grinding or polishing cannot be released sufficiently, and the resin film is coated to protect the device formation surface. May melt and damage the device formation surface.

  Accordingly, the present invention has been devised to solve the above-mentioned problems, and an adsorption device in which foreign matter such as grinding scraps and polishing scraps generated by processing of the object to be adsorbed does not easily enter and fill the pores of the adsorption unit, and the same It aims at providing the processing system provided with, and the processing method.

  The adsorbing device of the present invention is an adsorbing device including an adsorbent in which an adsorbing surface is divided into an inner region and an outer region surrounding the inner region, and at least a part of the outer region exudes liquid. It is characterized by being part. In addition, the adsorption | suction apparatus of this invention should just contain the said structure, For example, what should also be called the adsorption member which consists only of adsorption bodies shall be included. The inner region and the outer region may be divided by a member such as a partition wall.

  2) The suction surface is divided into an inner region including the center of the suction surface and one or more outer regions, and at least a part of the one or more outer regions is a liquid oozing part. And

  3) In the above 1) or 2), the seepage portion is made of porous ceramics.

  4) In the above 3), the porous ceramic is an alumina sintered body.

  5) In the above 3), the porous ceramic is a silicon carbide sintered body.

  6) In any one of 1) to 5) above, the adsorbent is a member constituting a vacuum chuck.

  In addition, the adsorption device of the present invention is characterized in that 7) In any one of 1) to 6), a liquid supply means for supplying a liquid to the exuding part is provided.

  8) A suction apparatus according to any one of 1) to 7) above, and a processing system for processing a workpiece held on the suction surface of the suction apparatus.

  Furthermore, the processing method of the present invention includes 9) a step of holding the workpiece on the suction surface of any one of the suction devices 1) to 7) and a step of processing the workpiece. It is characterized by.

  According to the adsorption devices 1) and 2), at least a part of the outer region is a liquid oozing part. As a result, even if the adsorbent is adsorbed using only the inner adsorbent and the surface of the adsorbent is repeatedly ground and polished, by supplying liquid to the outer region, grinding debris, polishing debris, etc. A vacuum chuck in which foreign matter hardly enters and fills the pores of the outer adsorbent can be obtained.

  Further, according to the adsorption device of the present invention, the adsorbent is made of an alumina sintered body or a porous ceramic of a silicon carbide sintered body, so that the rigidity of the vacuum chuck is maintained and the adsorbent is Most of the back surface can be adsorbed with a uniform force. Thereby, the flatness and parallelism of the to-be-adsorbed body after grinding or polishing can be reduced.

  Further, according to the adsorption device of the present invention, since the porous body is a silicon carbide sintered body, since the thermal conductivity and mechanical strength of silicon carbide itself are high, the heat dissipation characteristics and the mechanical characteristics are high in vacuum. It can be a chuck.

  In addition, according to the suction device of the present invention, since foreign matter such as grinding scraps and polishing scrapes hardly enter and fill the pores of the outer suction member, it can be used for a long period of time and has high reliability. A high adsorption device can be obtained. In particular, when a vacuum suction device is applied as the suction device, the above-described vacuum chuck is used as the suction means, and gas exhausting and suctioning gas operating means in the through hole, and a liquid that exudes liquid such as water and grinding fluid An effect can be heightened by comprising so that an operation means and also those switching means may be provided.

  Moreover, according to the processing system and the processing method of the present invention, as with the adsorption device, it can be used for a long period of time, and a processing system with high reliability can be obtained. In particular, the above-described vacuum chuck can be used as the suction unit, and the work can be processed with respect to the workpiece held by the suction unit.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings schematically shown.

  FIG. 1 shows an example of an embodiment of a vacuum chuck which is an example of the suction device of the present invention. 1A is a perspective view, and FIG. 1B is a cross-sectional view taken along line AA in FIG. In the following drawings, the same reference numerals are used to represent common parts.

  As shown in FIG. 1, the vacuum chuck 1 includes one or more suction bodies 2 in which a suction surface 2 b is divided into a plurality of regions by a partition wall 5 having an annular shape in plan view. That is, the adsorbing body 2 is divided into an adsorbing surface 2b into an inner region and an outer region surrounding the inner region, and at least a part of the outer region serves as a liquid oozing part. In this case, the inner region is surrounded by the outer region, but the inner region does not necessarily include the center of the suction surface 2b. Alternatively, the adsorbent 2 has an adsorbing surface 2b divided into an inner region including the center of the adsorbing surface 2b and one or more outer regions, and at least a part of the one or more outer regions is a liquid oozing part. It is good. In this case, the adsorbent 2 may have an outer region concentrically arranged in the inner region, or a plurality of small outer regions surrounding the inner region around the inner region. At least a part of at least one outer region of the one or more outer regions is used as a liquid oozing part.

  The vacuum chuck 1 has such an adsorbing body 2 and a suction path 3 a communicating with the pores 2 a existing inside the adsorbing body 2, and a support body 3 surrounding and supporting the peripheral edge of the adsorbing body 2. A suction target surface (not shown) such as a semiconductor wafer or a glass substrate is placed on the suction surface 2b, and suction paths 3a and 3h of the support 3 are sucked by suction means (not shown) such as a vacuum pump. The suction passages 3a and 3h are fixed (held) by sucking them sequentially through the suction grooves 3g opened concentrically or in a lattice shape and the pores 2a of the adsorbing body 2.

  The adsorbent 2 is a disc-shaped adsorbent made of a porous body having a three-dimensional network structure in which pores 2a that perform adsorption are continuous, and the adsorbing surface 2b is frequently used to maintain flatness. It is polished according to.

  The support 3 is formed of a disk-shaped dense body having a circular recess 3b on which the adsorbent 2 is mounted at the center, and the recess 3b is formed by a bonding layer 4 formed of glass, silicon, resin, or the like. The adsorbent 2 is fixed and supported inside. Further, the support 3 is configured such that the adsorption surface 2b of the adsorption body 2 and the top surface 3d of the outer wall 3c forming the recess 3b of the support 3 are located on the same plane. A flange portion 3e is provided on the outer peripheral edge, and the flange portion 3e is attached to various devices by means such as screwing or engagement.

  The partition wall 5 is joined to the support plate 3 f provided with the flange portion 3 e by the bonding layer 4 on the bottom surface and the adsorbent 2 by the bonding layer 4 on the side surface. The partition wall 5 is formed of a dense body having a width of about several millimeters, and by dividing the adsorbent 2 into 2c and 2d in the radial direction, various adsorbents having different diameters can be adsorbed individually. The adsorbent can be processed with high accuracy. The outer wall 3 c is bonded to the support plate 3 f by the glass-like bonding layer 4 at the bottom surface to form the support 3, and the inner peripheral surface is bonded to the adsorption portion 2 by the glass-like bonding layer 4.

  According to the adsorbing device of the present invention, in the suction path 3h of the support body 3, by providing a means for switching the exhaust operation means to the liquid supply operation means, foreign matters such as grinding dust and polishing dust can be formed in the pores of the outer adsorbent 2d. The vacuum chuck can hardly enter and fill 2a.

  The adsorbent 2d constituting the vacuum chuck 1 is, for example, a porous annular body having an outer diameter of 140 to 300 mm, an inner diameter of 103 to 205 mm, and a thickness (d2) of 5 to 15 mm. It is a porous disk-shaped body having an outer diameter of 100 to 200 mm and a thickness (d2) of 5 to 15 mm. The support 3 is a dense disc-shaped frame having a circular recess 3b at the center, for example, an outer diameter between the outer walls 3c of 143 to 380 mm and a thickness (d3) of 14 to 60 mm. The width of the partition wall 5 is 0.1 to 5.0 mm.

  In the vacuum chuck 1, when the object to be adsorbed is adsorbed by the adsorbing surface 2b of the adsorbing body 2c, the suction path 3h is switched to liquid supply, and the pores 2a of the adsorbing body 2c are filled with liquid so Foreign matters such as scraps are less likely to enter and fill the pores 2a of the outer adsorbent 2d.

  In the vacuum chuck 1 of the present invention, it is preferable that a plurality of partition walls 5 are provided concentrically. This is because an object to be adsorbed such as various semiconductor wafers having different diameters can be shared by the same vacuum chuck 1. Further, it is possible to select an appropriate suction force according to the diameter of the semiconductor wafer, and it is not necessary to apply a large load to the suction means such as a vacuum pump.

  In particular, when the object to be adsorbed is a semiconductor wafer having a diameter of 152.4 mm (6 inches), 203.2 mm (8 inches), and 304.8 mm (12 inches), the center of the partition wall 5 in the width direction is a vacuum chuck. It is preferable that the radius is 75 to 77 mm and 100 to 102 mm with the center of 1 as the starting point.

  When the adsorbent is a disk-like body such as a semiconductor wafer, it is preferable that a plurality of the partition walls 5 are provided concentrically as described above, but the adsorbent is an elliptical body. In some cases, it is preferable that a plurality of partition walls 5 are provided concentrically.

  A vacuum chuck 1 shown in FIG. 2 includes an adsorbing body 2 in which an adsorbing surface 2 b is divided into a plurality of regions by an annular partition wall 5 in plan view, and the adsorbing body 2 is configured integrally with the partition wall 5. The support 3 is provided. By adopting such a configuration, a heat radiation loss between the adsorbent body 2 and the partition wall 5 generated when the adsorbent body 2 and the partition wall 5 are separately formed does not occur. It can be.

  In the vacuum chuck 1 of the present invention, the adsorbent 2 is preferably made of porous ceramics, and the support 3 is preferably made of dense ceramics. Examples of such ceramics include alumina and silicon carbide. Can be used. With such a configuration, the rigidity of the vacuum chuck 1 is maintained, and most of the back surface of the object to be adsorbed is adsorbed with a uniform force. Therefore, the flatness and parallelism of the object to be adsorbed after grinding and polishing are used. Can be reduced.

  Further, the heat dissipation characteristics and mechanical characteristics of the vacuum chuck 1 are greatly influenced by the composition of the materials constituting the adsorbent 2 and the support 3.

  In particular, when the ceramic is silicon carbide, since the thermal conductivity and mechanical strength of the silicon carbide itself are high, a vacuum chuck having high heat dissipation characteristics and mechanical characteristics can be obtained.

  When silicon carbide is formed into a dense sintered body having a relative density of 98%, the thermal conductivity is 200 W / (m · k), the three-point bending strength is 450 MPa, and all the characteristics are high. Other ceramics such as silicon nitride, aluminum nitride, zirconium oxide, etc. have low thermal conductivity or mechanical strength.

  If the ceramic is alumina, the raw material of alumina itself is inexpensive, so that the vacuum chuck itself can be obtained at low cost.

  In addition, since the support 3 is required to have high heat dissipation characteristics and mechanical characteristics like the adsorbent 2, the relative density is preferably 98% or more regardless of the composition.

  Furthermore, when ceramic particles are bonded to each other by silicon, porous ceramics can improve heat conduction between ceramic particles due to silicon having high thermal conductivity, resulting in a vacuum chuck with higher heat dissipation characteristics. be able to.

  In particular, in the vacuum chuck 1 of the present invention, it is preferable that the porous ceramics forming the adsorbent 2 have silicon carbide particles bonded together by silicon. This is because silicon has good wettability with respect to silicon carbide particles and the silicon itself has high thermal conductivity, so that the heat dissipation characteristics and mechanical characteristics, particularly rigidity and highness of the adsorbent 2 can be increased.

  Here, a state in which silicon carbide particles are bonded with silicon will be described with reference to FIG. FIG. 3 is a schematic diagram showing a state in which silicon carbide particles 7 are joined with silicon 8.

  The porous ceramic forming the adsorbent 2 is a porous body in which silicon 8 joins silicon carbide particles 7 and 2a has pores. The wettability of the silicon 8 to the silicon carbide particles 7 is good, and the silicon 8 easily adheres to the silicon carbide particles 7, and the deposited silicon 8 is firmly connected to each other to form a silicon phase. The rigidity and heat conductivity can be kept high. For example, the Young's modulus of the porous body is 22 GPa or more and 64 GPa or less, and the thermal conductivity is 70 W / (m · k) or more and 110 W / (m · k) or less. can do. In the process of forming the silicon phase, it is preferable not to generate non-connected portions 9 such as voids and bubbles in the silicon phase. This is because such an unconnected portion 9 decreases the thermal conductivity.

  In addition, the presence or absence of the non-connection part 9 can be judged by observing in the range of 1.8 mm x 2.0 mm, for example using a scanning electron microscope as magnification 50-5000 times. Moreover, the area ratio of the non-connecting portion 9 is defined as a ratio represented by the following mathematical formula (1), and it is preferable that the heat dissipation characteristics of the adsorbent body 2 be made small in the area ratio of the non-connecting portion 9. 5% is preferable.

Area ratio of unconnected portion 9 = (area of unconnected portion 9 / (area of silicon 8 + area of unconnected portion 9)) × 100 (%) (1)
This area ratio can be determined as follows. That is, a part cut out from the adsorbent 2 is embedded in a resin in a vacuum to form a cylindrical sample, and the flat surface of this sample is polished with a diamond abrasive to make a mirror surface, followed by an industrial microscope (Nikon ECLIPSE). LV150) is used to save an image of this mirror surface taken at 5 to 50 times in JPEG format. Next, the image file stored in the JPEG format is subjected to image processing using software (Adobe (registered trademark) Photoshop (registered trademark) Elements) and stored in the BMP format. Specifically, the chromatic color on the image is deleted, and black and white gradation (black and white) is performed. In this two-gradation, a threshold value for distinguishing between silicon carbide particles 7 and silicon 8 is set while comparing with an image taken with an industrial microscope (Nikon ECLIPSE LV150). After setting the threshold value, the area of the silicon 8 is read in units of pixels from the two-graded image using free software “area from image”. The unconnected portion 9 can also be read by the same method as described above, and can be calculated by the above formula (1) using those results.

  Further, the vacuum chuck 1 of the present invention is more reliable than the case where the adsorbent 2 is bonded to the support 3 with resin because the adsorbent 2 is bonded to the support 3 with glass, and silicon. Can be bonded at a temperature considerably lower than the melting point of 1410 ° C., for example, 900 to 1000 ° C. Therefore, it is not necessary to melt silicon bonding ceramic particles, and a highly reliable vacuum chuck can be obtained. .

  In particular, the glass in which the support 3 is bonded to the adsorbent 2 is composed of 30 to 65% by mass of silicon (Si) in terms of oxide and aluminum (100% by mass) with respect to a total of 100% by mass of the composition forming the glass. Al) 10-40% by mass, boron (B) 10-20% by mass, Ca 4-5% by mass, Mg 1-5% by mass, Ti 5% by mass or less (excluding 0% by mass) Glass, or silicon (Si) 30 to 65% by mass, aluminum (Al) 10 to 40% by mass, boron (B) 10 to 20% by mass, calcium (Ca) 4 to 5% in terms of oxides, respectively. Glass containing 1% by mass, 1-5% by mass of magnesium (Mg), 6% by mass or less (excluding 0% by mass) of barium (Ba), and 5% by mass or less (excluding 0% by mass) of strontium (Sr) It is preferable that This is because the adsorbent 2 can be firmly bonded to the support 3 by making the glass composition in this way.

  Measurement of the ventilation resistance of the vacuum chuck 1 using the adsorbent 2 and the support 3 shown in FIGS. 1 and 2 is performed by the method described below. First, a vacuum pump (not shown) is connected to the suction path 3a via a pipe (not shown), and then sucked at a pressure of 80 to 90 kPa, for example. By this suction, pressure loss is generated according to the thickness (d2), porosity, and average pore diameter of the adsorbent 2. About this pressure loss, the value can be read with the pressure gauge installed in the pipe. If this pressure loss value is large, it indicates that the ventilation resistance is high. If the pressure loss value is small, the ventilation resistance is low. It shows that.

  Moreover, when the porosity of the adsorbent 2 is high and the average pore diameter is large, the airflow resistance is lowered, but the rigidity and the heat dissipation characteristics are lowered. On the other hand, when the porosity is low and the average pore diameter is small, the airflow resistance is increased, but the rigidity and heat dissipation characteristics are improved. From such a viewpoint, the adsorbent 2 preferably has a porosity of 27% to 40% and an average pore diameter of 20 μm to 40 μm. By setting the porosity and the average pore diameter within this range, the ventilation resistance, rigidity, and heat dissipation characteristics of the vacuum chuck 1 can be optimized. For example, the Young's modulus indicating rigidity is set to 1 GPa or more and 10 GPa by a measurement method described later. It can be as follows.

  Note that the porosity and average pore diameter of the adsorbent 2 can be determined in accordance with the Archimedes method and JIS R 1655-2003, respectively.

  FIG. 4 is a cross-sectional view showing a means for measuring the rigidity of the vacuum chuck 1.

  As for the rigidity of the vacuum chuck 1, as shown in FIG. 4, the vacuum chuck 1 is supported when the vacuum chuck 1 is supported by the support ring 10 concentrically with the vacuum chuck 1 and a load is applied to the center of the vacuum chuck 1. The displacement amount of 1 is measured with an electric micrometer (not shown), and the Young's modulus may be obtained by the following mathematical formula (2).

E = ((3 + υ) P (d / 2) ² · 12 (1-υ)) / (16π (1 + υ) · h ³ · ω) (2)
E: Young's modulus (GPa) of the vacuum chuck 1
υ: Poisson's ratio of vacuum chuck 1 P: Load (N)
d: Inner diameter of support ring 10 (mm)
h: Thickness (mm) of the vacuum chuck 1 (h in FIG. 1 is d3)
ω: displacement of the vacuum chuck 1 (mm)
FIG. 5 is a cross-sectional view showing the thermal conductivity measuring means of the vacuum chuck 1. Specifically, the measurement of heat dissipation characteristics is as follows. First, the soaking plate 11 made of silicon carbide is placed on the hot plate 12, and then the hot plate 12 is heated to keep the soaking plate 11 at 60 ° C. In this state, the vacuum chuck 1 is placed on the soaking plate 11, and the temperature at the center of the back surface of the support 3 after 50 seconds is measured with the thermocouple 13, and a recorder connected to the thermocouple 13 is measured. Record the measured temperature at 14. If this temperature is high, the heat radiation characteristic of the vacuum chuck 1 is high, and if this temperature is low, it can be said that the heat radiation characteristic is low.

  As described above, the vacuum suction device of the present invention uses the above-described vacuum chuck 1 as a suction means, switches the exhaust means of the suction path 3h to the liquid supply means, and fills the pores 2a of the adsorbent 2d with the liquid. Since foreign matter such as grinding scraps and polishing scrapes hardly enter and fill the pores 2a of the outer adsorbent 2d, it can be used for a long period of time and has a highly reliable vacuum. It can be an adsorption device.

  The vacuum chuck 1 described above is used as a suction device, and includes a grinding blade and a grinding wheel for processing a workpiece fixed to the suction device, and the grinding blade and the grinding stone are moved relative to the suction target. By providing the moving mechanism, a processing system including a processing device such as a grinding device can be configured. Moreover, the processing method which performs the process of hold | maintaining a workpiece on the adsorption | suction surface of the adsorption | suction apparatus mentioned above, and the process of processing to a workpiece can be applied. As described above, since the workpiece fixed (held) to the suction device can be processed, it can be used for a long period of time, like a vacuum suction device, and a highly reliable processing system and It can be a processing method.

  6A and 6B show another embodiment of the vacuum chuck of the present invention. FIG. 6A is a perspective view, and FIG. 6B is an enlarged cross-sectional view taken along line AA of FIG.

  A vacuum chuck 1 shown in FIG. 6 is a vacuum chuck including an adsorbing body 2 in which an adsorbing surface 2b is divided into a plurality of regions by a partition wall 4 having an annular shape in plan view. Since the suction surface 2b has a square shape, the vacuum chuck is suitable when the object to be sucked has a square plate shape.

The support body 3 is provided with a recess 3b in the center, and the adsorbent body 2 including a partition wall 4 is disposed in the recess 3b. The support 3 is made of, for example, a sintered body containing silicon carbide as a main component, and the suction grooves 3g ₁ and 3g ₂ that open to the bottom surface of the recess 3b, and the suction path 3a that communicates with the suction grooves 3g ₁ and 3g _{2. 1} and 3a ₂ are provided. By appropriately selecting the suction paths 3a ₁ and 3a ₂ , the size of the suction surface 2b can be freely set according to the size of the object to be adsorbed.

Specifically, when adsorbing an adsorbed object whose size in the plan view is close to the entire adsorbing surface 2b, air is sucked from all of the suction paths 3a ₁ and 3a _2. The adsorbents are adsorbed and held through the suction grooves 3g ₁ and 3g ₂ . Further, in the case of adsorbing the size and substantially the same size of the adsorbent portion size of the adsorbent when viewed in plan is surrounded by the partition walls 4, the air sucked from only the suction path 3a _1, while holding by suction the object adsorbent through the suction grooves 3 g _1, the suction passage 3a ₂ a liquid such as water or grinding fluid supplied from, by filling the liquid into the pores of the adsorbent 2d, the adsorbent Even if surface grinding and polishing are repeated, a vacuum chuck can be obtained in which foreign matters such as grinding scraps and polishing scraps hardly enter and fill the pores of the outer adsorbent 2d.

  A base (not shown) for supporting and fixing the vacuum chuck 1 is provided below the support 3, and the support 3 and the base (not shown) are installed at equal intervals. The hole 15 is connected and fixed via a bolt (not shown) or the like.

  Next, an example of the manufacturing method of the vacuum chuck of this invention is demonstrated. In order to obtain the adsorbent 2 which is a part of the vacuum chuck 1 of the present invention, first, silicon powder having an average particle diameter of 1 to 90 μm with respect to 100 parts by mass of α-type silicon carbide powder having an average particle diameter of 105 to 350 μm. 15-30 parts by mass is prepared, and a thermosetting resin such as a phenol resin, in which the residual carbon ratio after the subsequent degreasing treatment is 30% by mass or more with respect to 100% by mass of the degreased body as a molding aid. Add at least one of epoxy resin, furan resin, phenoxy resin, melamine resin, urea resin, aniline resin, unsaturated polyester resin, urethane resin, methacrylic resin, ball mill, vibration mill, colloid mill, attritor Mix evenly with a high-speed mixer. In particular, a resol-type or novolac-type phenol resin is suitable as a molding aid because it has low shrinkage after thermosetting.

  Since the addition amount of the molding aid affects the density of the molded body, it also affects the porosity and average pore diameter of the adsorbent 2. In order to set the porosity of the adsorbent 2 to 27% or more and 40% or less and the average pore diameter to 20 μm or more and 40 μm or less, the addition amount of the molding aid is 5 to 20 mass per 100 parts by mass of the α-type silicon carbide powder. Part.

  By the way, although α type and β type exist in silicon carbide, α type generally has higher oxidation resistance than β type, and hardly contains residual carbon or residual silicon inside the particles. For these reasons, α-type silicon carbide is used as the starting material.

  In addition, it is important that the average particle size of the α-type silicon carbide powder is 105 to 350 μm. If the average particle size is less than 105 μm, the powder having a small particle size forms closed pores or reduces the pores themselves. This is because when the semiconductor wafer or the glass substrate is adsorbed, the airflow resistance is increased, and when the average particle diameter exceeds 350 μm, the density of the adsorbent 2 is decreased, and the strength is decreased. By setting the average particle size of the α-type silicon carbide powder to 105 to 350 μm, it is possible to obtain the adsorbent 2 that has low ventilation resistance and does not cause a decrease in strength.

  In addition, the silicon (silicon) powder becomes a silicon phase in a later heat treatment to connect silicon carbide particles. It is important that the silicon powder is a powder having an average particle diameter of 1 to 90 μm and the ratio thereof is 15 to 30 parts by mass with respect to 100 parts by mass of the α-type silicon carbide powder. This is because when the average particle size of the silicon powder is less than 1 μm, the dispersibility of the silicon powder is poor and silicon carbide particles can be connected only locally. On the other hand, when the average particle diameter of the silicon powder exceeds 90 μm, the silicon powder melts and moves so as to cover the silicon carbide powder in the subsequent heat treatment, so that the space where the silicon powder is partially agglomerated and occupied This is because large pores remain and cause a decrease in strength.

  The ratio of silicon powder to 15 to 30 parts by mass with respect to 100 parts by mass of α-type silicon carbide powder is that when the ratio of silicon powder is less than 15 parts by mass, the ratio of silicon carbide to particles is low. This is because the particles cannot be sufficiently connected. On the other hand, when the ratio exceeds 30 parts by mass, silicon is easily segregated, the ratio of silicon carbide having relatively good mechanical characteristics is lowered, and sufficient mechanical characteristics cannot be obtained. By setting the ratio of the silicon powder to 15 to 30 parts by mass, the adsorbent 2 having a homogeneous structure with sufficient mechanical characteristics can be obtained.

  The purity of the silicon powder is preferably high, preferably 95% by mass or more, and particularly preferably 99% by mass or more of high-purity silicon. In addition, the shape of the silicon powder to be used is not particularly limited, and not only a spherical shape or a shape close thereto, but also an irregular shape can be suitably used.

  Each average particle diameter of these silicon carbide powder and silicon powder can be measured by a liquid phase precipitation method, a light drop method, a laser scattering diffraction method, or the like.

  Next, the mixed raw material is granulated using various granulators such as a rolling granulator, a spray granulator, a compression granulator, an extrusion granulator.

  Next, this granule is formed into a desired shape, for example, a disk shape or an annular shape, by a molding means such as dry pressure molding or cold isostatic pressing, and if necessary, argon, helium After performing degreasing treatment at 400 to 600 ° C. in a non-oxidizing atmosphere such as neon, nitrogen, vacuum, etc., heat treatment is performed at 1400 to 1450 ° C. in a non-oxidizing atmosphere similarly to the degreasing treatment. -It can be a composite made of silicon.

  In order to lower the temperature of the heat treatment, the purity of the silicon powder is preferably 99.5 to 99.8% by mass.

  In the heat treatment, it is important to set the temperature to 1400 to 1450 ° C. This is because if the heat treatment temperature is less than 1400 ° C., the silicon powder is not sufficiently melted, so that silicon carbide crystal particles cannot be connected as the silicon phase. If the heat treatment temperature exceeds 1450 ° C., the silicon evaporates, resulting in a decrease in strength. This is because it is easy and the manufacturing cost increases. By setting the heat treatment temperature to 1400 to 1450 ° C., the silicon powder is appropriately melted without evaporating, so that a cavity is interposed between adjacent silicon carbide particles without generating two or more joints. Further, silicon carbide particles can be connected as a silicon phase, and appropriate mechanical strength and thermal conductivity can be obtained, and the manufacturing cost can be reduced. In particular, the heat treatment temperature is preferably 1420 to 1450 ° C. By performing heat treatment in this temperature range, a composite having a three-point bending strength of 30 MPa or more and a Young's modulus of 30 GPa or more can be obtained. In addition, in order to coat silicon carbide crystal particles with silicon, after silicon powder is sufficiently melted, silicon evaporates or partially reacts with carbon floating in the atmosphere and changes to silicon carbide. We must make sure that there is nothing. In order to coat silicon carbide particles with silicon from such a viewpoint, the temperature may be set to 1420 to 1440 ° C.

  The composite obtained by such a manufacturing method can be processed into an adsorbent 2 by subjecting the upper surface thereof to machining such as grinding and polishing, and has a diameter of 140 to 300 mm and a thickness (d2). May be a porous body having a disk shape of 5 to 10 mm.

  The suction surface 2b needs to be flattened as much as possible because the surface state affects the accuracy of the processed semiconductor wafer or glass substrate, and the flatness is at least 1 μm or less, preferably the flatness is 0. It is desired to be 3 μm or less.

Next, a support plate 3f having a dense disk shape with silicon carbide as a main component and a thickness of 9.3 to 50 mm is prepared. SiO ₂ is 30 to 65 wt% on the support plate 3f, _Al 2 _{O 3} is 10 to 40 _wt%, B 2 _{O 3} is 10 to 20 mass%, CaO 4 to 5 wt%, MgO 1 to 5 mass %, TiO ₂ is 5% by mass or less (excluding 0% by mass) of paste-like glass, or SiO ₂ is 30 to 65% by mass, Al ₂ O ₃ is 10 to 40% by mass, and B ₂ O ₃ is 10%. ~ 20 mass%, CaO 4-5 mass%, MgO 1-5 mass%, BaO 6 mass% or less (excluding 0 mass%) and SrO 5 mass% or less (excluding 0 mass%) Paste-like glass is applied to the recess 3b, and the adsorbent body 2c having a disk shape in which the glass is previously applied to the outer peripheral surface is placed so as to be substantially concentric. Here, the ratio of each said component is a ratio with respect to the total of 100 mass% of the composition which forms glass.

  The partition 5, the adsorbent 2 d that is an annular body, and the outer wall 3 c that is composed of a silicon carbide sintered body are sequentially placed on the support plate 3 f from the thickness direction with a dedicated pressurizing device. Pressurize. In addition, the said glass is previously apply | coated to the inner peripheral surface, outer peripheral surface, and bottom face of the partition 5 and the adsorption body 2d, and the inner peripheral surface and bottom face of the outer wall 3c. After the pressurization, heat treatment is performed at 950 to 980 ° C., whereby the adsorbent 2, the partition wall 5, and the outer wall 3 c are bonded to the support plate 3 f with the glassy bonding layer 4. At the same time, the outer wall 3c and the support plate 3f form the support 3 to obtain the vacuum chuck shown in FIG.

  The vacuum chuck shown in FIG. 2 in which the partition wall 5 and the support 3 are integrally formed can be obtained by the following method. That is, first of all, silicon carbide is the main component, and includes an outer wall 3c and a partition wall 5 in which a through-hole 6 that can be ventilated is formed in advance, a circular recess 3b in the center, and an annular recess A support 3 that is a substantially disk-shaped dense frame body provided with 3b is prepared, and any one of the above-described glasses is applied to the recess 3b. After the glass application, the adsorbent 2 is placed in the recess 3b and pressurized from the thickness direction with a dedicated pressurizing device. After pressurization, the adsorbent 2 and the support 3 are bonded by the glassy bonding layer 4 by heat treatment at 950 to 980 ° C., and the vacuum chuck shown in FIG. 2 can be obtained.

  According to such a vacuum chuck 1 of the present invention, the exhaust means in the suction passage 3h is switched to the liquid supply means, and the pores 2a of the adsorbent 2d are filled with liquid, so that only the inner adsorbent 2c is used. Even if the object to be adsorbed is adsorbed and the surface of the object to be adsorbed is ground and polished repeatedly, foreign matters such as grinding scraps and polishing scraps hardly enter and fill the pores 2a of the outer adsorbent 2d.

It is a figure explaining one Embodiment of the vacuum chuck of this invention, (a) is a perspective view, (b) is sectional drawing in the AA line in the figure (a). It is a figure explaining other embodiment of the vacuum chuck of this invention, (a) is a perspective view, (b) is sectional drawing in the AA line in the figure (a). It is a mimetic diagram showing the state where the crystal grain of silicon carbide was joined with silicon. It is sectional drawing which shows the measurement means of the rigidity of a vacuum chuck. It is sectional drawing which shows the measurement means of the heat conductivity of a vacuum chuck. It is a figure explaining other embodiment of the vacuum chuck of this invention, (a) is a perspective view, (b) is sectional drawing in the AA line in the figure (a). It is a figure explaining an example of the conventional vacuum chuck, (a) is a perspective view of the chuck table provided with the true chuck (adsorption plate), (b) is a schematic sectional drawing of the chuck table of (a). . It is a figure explaining an example of the conventional vacuum suction device (vacuum chuck), (a) is a horizontal sectional view of a vacuum suction device (vacuum chuck), (b) is an AA line of (a). It is a vertical sectional view.

Explanation of symbols

1: Vacuum chuck (Suction device)
2: Adsorbent 2a: Pore 2b: Adsorption surface 2c: Inner adsorbent 2d: Outer adsorbent 3: Support 3a: Inner suction path 3b: Recess 3c: Outer wall 3d: Top surface 3e: Flange 3f: Support Plate 3g: Suction groove 3h: Outer suction path 4: Bonding layer 5: Partition wall 6: Through hole 7: Silicon carbide particles 8: Silicon 9: Unconnected portion 10: Support ring 11: Heat equalizing plate 12: Hot plate 13 : Thermocouple 14: Recorder 15: Mounting hole

Claims (9)

An adsorption device comprising an adsorbent whose adsorption surface is divided into an inner area and an outer area surrounding the inner area, wherein at least a part of the outer area is a liquid oozing portion. apparatus. The adsorption surface is divided into an inner region including the center of the adsorption surface and one or more outer regions, and at least a part of the one or more outer regions is a liquid oozing portion. apparatus. The adsorbing device according to claim 1, wherein the oozing portion is made of porous ceramics. The adsorption device according to claim 3, wherein the porous ceramic is an alumina sintered body. The adsorption device according to claim 3, wherein the porous ceramic is a silicon carbide sintered body. 6. The suction device according to claim 1, wherein the suction body is a member constituting a vacuum chuck. The adsorbing device according to claim 1, further comprising a liquid supply unit configured to supply a liquid to the exuding part. A processing system comprising: the suction device according to claim 1; and a processing device for processing a workpiece held on the suction surface of the suction device. A processing method comprising: a step of holding a workpiece on the suction surface of the suction device according to any one of claims 1 to 7; and a step of processing the workpiece.

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