JP2007221030A - Processing method for substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flattening technique for finishing a semiconductor substrate represented by a single-crystal silicon wafer to higher flatness. <P>SOLUTION: A resin layer 602 is formed on one surface of a substrate 601 (Fig. 5(A)) of single-crystal silicon cut out of an ingot (Fig. 5(B)) to obtain a flat surface 602b by cutting the surface of the resin layer 602 (Fig. 5 (C)). The other exposed surface of the substrate 601 is ground to be made flat based upon the flat surface 602b as a reference surface (Fig. 5 (E)). Then the resin layer 602 is removed (Fig. 5 (G)) and the surface 601c which still waves is further grounded to be made flat, thus obtaining a flat surface 601d. Consequently, waving on both the sides of the substrate 601 is removed to flatten the substrate 601. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for flatly processing a semiconductor wafer substrate or the like cut out from an ingot, and more particularly to a technique for processing a substrate having waviness on a surface to obtain a highly accurate plane.

  A single crystal semiconductor wafer (hereinafter referred to as a substrate) such as silicon may be cut out by a wire saw from a lump state called an ingot. FIG. 7 is a conceptual diagram showing a method for obtaining a substrate from an ingot in the prior art. FIG. 7A conceptually shows a state where the ingot 71 is sliced by the wire saw 72. The wire saw 72 includes a wire 7a having a thickness of about 0.1 to 0.2 mm such as a piano wire.

  FIG. 7B conceptually shows the state of the kerf formed by the wire saw 72. FIG. 7C is a conceptual diagram showing the state of the substrate cut out from the ingot. The wire saw 72 is reciprocated while being pressed against the side surface of the ingot 71, and the loose abrasive grains are supplied to the processing point, whereby the thickness of the wire 72a plus the kerf 74 is formed. Then, by passing through the kerf 74, a plurality of ingots 71 can be cut and a substrate 73 shown in FIG. 7C can be obtained. At the time of this cutting, the wire 72a is reciprocated by applying a necessary tension to form the kerf 74. However, due to the influence of the loose abrasive on the processing point, the wire 72a The movement toward the bottom of the groove is somewhat meandering. Therefore, irregularities are formed on the side surface 75 of the kerf 74.

  FIG. 7C conceptually shows an enlarged state of the substrate 73 and a part 76 thereof. Through the state shown in FIGS. 7A and 7B, a slice streak 77 due to the unevenness is observed on the cut out substrate 73. The slice stripe 77 has irregularities of about several μm at a pitch of several millimeters. The slice stripes 77 swell the substrate surface that reduces the flatness of the substrate 73.

  Waviness on the surface of the substrate 73 caused by the slice stripes 77 is not preferable for manufacturing a highly integrated semiconductor device that forms fine wirings and the like. As a technology to deal with this problem, a resin layer is formed by applying a resin to one side of a substrate cut out from an ingot, and then a reference surface is formed by pressing the resin layer, and this reference surface is sucked. There has been proposed a method of removing the waviness described above by fixing and grinding the other surface (for example, Patent Document 1). Further, there is provided a method of applying wax on a substrate, pressing the surface against a plate to improve the flatness of the wax surface, and then subjecting the other surface to suction fixing and grinding the other surface ( For example, Patent Document 2).

JP-A-11-111653 (abstract) JP 2000-5982 (Abstract)

However, in the method of obtaining a flat surface by pressing the resin surface or the wax surface against a plate or the like, when surface pressure is applied to the substrate, the swell of the substrate is corrected by deformation of the substrate, so when the surface pressure is released The swell of the board is restored. For this reason, the above-described conventional technique is insufficient as a technique for obtaining flatness on a substrate of a semiconductor integrated circuit having a higher degree of integration.
Accordingly, an object of the present invention is to obtain a highly accurate plane by processing a substrate having a undulation on the surface.

  The present invention is a method for flatly processing a substrate cut out from an ingot, the step of forming a resin layer on one surface of the substrate, the step of cutting the resin layer, and the surface of the cut resin layer And the other surface of the substrate is ground, and the other ground surface is suction-fixed and the one surface of the substrate is ground.

  According to the present invention, first, a resin layer is formed on one surface of a substrate with undulations. Since this resin layer is formed following the waviness of the substrate, waviness is formed on the surface of the resin layer. Then, the other surface of the substrate is adsorbed by, for example, an adsorbing means, and the exposed surface of the resin layer is flattened by cutting the undulation of the resin layer surface using, for example, a cutting tool. At this time, since it is not necessary to apply pressure on the surface of the substrate, the undulation of the substrate is not corrected.For this reason, after removing the substrate from the suction means or the like, the flatness of the resin layer surface is not disturbed and is flattened. The resin layer can be used as a reference surface in later processing. After the resin layer is flattened, the surface is sucked and fixed to a suction means or the like, and the other surface of the substrate is ground to flatten the other surface of the substrate. At this time, since the surface of the previously flattened resin layer is fixed to the suction means or the like as a reference surface, the waviness of the substrate is not corrected by the suction force. Therefore, after the planarization of the substrate on the other surface is completed, the undulation is not restored on the planarized surface. Then, after the planarization of the other surface of the substrate is completed, the remaining one surface with the other planarized surface as a reference surface is planarized by grinding. In this way, a substrate from which the surface waviness is removed can be obtained.

  In the present invention, the resin layer can be formed by applying a liquid material on the surface of the substrate and solidifying it, or by sticking a film-like material on the surface of the substrate. As the former, those capable of controlling liquefaction and solidification by temperature control such as wax, phenol, ethylene carbonate and the like can be used. As the latter, polyolefin, polyethylene, polyimide, or the like made into a film and an adhesive applied on one surface thereof can be used. As the resin layer, a material that can be solidified by ultraviolet irradiation or the like can be selected.

  In the step of cutting the surface on which the resin layer of the present invention is formed, it is desirable to fix the other surface of the substrate by supporting at least three points. According to this aspect, since the substrate is supported by point contact, the substrate can be stably supported in a state in which the influence of the undulation of the substrate is eliminated as much as possible. Further, unlike the case of fixing with a surface, the swell of the substrate is pressed down and the swell is not corrected. For this reason, when a board | substrate is removed from an adsorption | suction means etc., the phenomenon that the correction | amendment state of a wave | undulation is cancelled | released and a wave | undulation is restored can be suppressed.

  In the present invention, it is desirable to remove the resin layer by peeling or the like before grinding one surface. In this embodiment, after removing the resin layer functioning as a reference surface for planarization and exposing the substrate surface with waviness, the substrate surface is ground and planarized. The resin layer can be easily peeled off by heating or using a special release agent. Further, a strong adhesive tape can be used as the film-like material, which can be peeled off after being stuck on the surface of the substrate and cut. Moreover, a strong adhesive tape for peeling can be stuck on the surface of the film-like one, and the strong adhesive tape for peeling can be pulled in a direction opposite to the substrate to peel the film-like one.

  According to the present invention, since a resin layer is formed on a substrate and the surface of the resin layer is flattened by cutting, a flat surface is obtained. Therefore, the undulation existing on the substrate surface affects the flatness of the resin surface. In the end, a substrate with high flatness from which the undulation is removed can be obtained.

1. First embodiment (cutting device)
FIG. 1 is a perspective view showing an example of a cutting apparatus that cuts and flattens a resin layer. The cutting device 10 includes a base 11 mainly composed of a rectangular parallelepiped portion having a horizontal upper surface. The base 11 has a wall portion 12 standing perpendicular to the upper surface at one end portion in the longitudinal direction. In FIG. 1, the longitudinal direction, the width direction, and the vertical direction of the base 11 are indicated by arrows Y, X, and Z, respectively. The upper surface of the base 11 has a processing area 11A from the substantially central portion in the longitudinal direction to the wall 12 side, and the opposite side supplies the substrate before processing to the processing area 11A and supplies the substrate after processing. -It is set as the collection area 11B.

  A rectangular recess 13 is formed in the processing area 11A, and a disc-shaped chuck table 15 is provided in the recess 13 so as to be movable in the Y direction via a moving table 14. The moving table 14 is slidably attached to a guide rail that extends in the Y direction and is arranged in the base 11, and is reciprocated in the same direction by an appropriate drive mechanism (not shown).

  One end of bellows-like covers 16 and 17 is attached to both ends of the moving table 14 in the moving direction, and the other ends of the covers 16 and 17 are opposed to the inner surface of the wall portion 12 and the wall portion 12. It is attached to the inner wall surface of the recess 13 to be respectively. These covers 16 and 17 cover the moving path of the moving table 14 and prevent cutting chips and the like from falling on the moving path, and expand and contract as the moving table 14 moves.

  The chuck table 15 is fixed on the movable table 14 so that the upper surface, which is the suction surface of the substrate, is horizontal. FIG. 2 is a side view (A) and a top view (B) showing the configuration in the vicinity of the chuck table 15 of the cutting apparatus 10. As shown in FIG. 2, the chuck table 15 has a circular recess 15a into which the substrate 601 is fitted. Near the center of the bottom surface 15b of the concave mold 15a, two vacuum holes 15c connected to a vacuum pump (not shown) are formed, and three conical support portions 15d are disposed on the bottom surface 15b. With the surface on which the resin layer 602 is formed facing upward, the substrate 601 is disposed in the recess 15a, and a vacuum pump (not shown) is operated to suck the air in the recess 15a from the vacuum hole 15c. Is sucked and held on the chuck table 15. At this time, the substrate 601 is stably supported by the three points of the support portion 15d without rattling. Further, since it is supported by point contact, in the supported state, the influence of the undulation of the opposite surface of the substrate 601 is eliminated. In addition, since the support is based on point contact that is not surface contact, the undulation of the surface of the substrate 601 is difficult to be corrected. For this reason, it is possible to suppress the occurrence of the undulation that has been corrected when the suction state is released and the substrate 601 is removed from the chuck table 15. In addition, as a support structure by point contact, it is good also as a structure which supports by four or more support points.

  Returning to FIG. 1, the chuck table 15 moves to the wall 12 side and is positioned at a predetermined processing position. A cutting unit (cutting means) 20 is disposed above the processing position. The cutting unit 20 is attached to the wall portion 12 via a moving plate 32 and a guide rail 31 so as to be movable up and down, and is moved up and down by a feed mechanism 30.

  The cutting unit 20 includes a cylindrical housing 22 whose axial direction extends in the Z direction, a rotary shaft 23 that is coaxially and rotatably supported by the housing 22, and a servo motor 24 that rotationally drives the rotary shaft 23. A disc-shaped wheel mount 25 coaxially fixed to the lower end of the rotary shaft 23, and the housing 22 is fixed to the moving plate 32 via a block 34. The wheel mount 25 is rotated in the direction of the arrow (described on the upper surface of the wheel mount 25) in FIG.

  As shown in FIG. 2A, a cutting tool 26 having a blade portion made of diamond or the like is detachably attached to the lower surface of the wheel mount 25, and the workpiece is cut by the cutting tool 26. The bite is made of a hard material such as diamond, cemented carbide or CBN.

  The chuck table 15 is reciprocated between a processing position immediately below the cutting unit 20 and a substrate attaching / detaching position that is a predetermined distance away from the wall 12. At the substrate attachment / detachment position, the substrate to be cut is placed on the chuck table 15 and the substrate after the cutting is removed from the chuck table 15.

  As shown in FIG. 1, a rectangular recess 18 is formed in the supply / recovery area 11B, and a bottom of the recess 18 is provided with a two-link type horizontal swivel arm 60a that can be raised and lowered. A transfer mechanism 60 having a fork (suction means) 60b attached to the tip is installed.

  A supply arm 63 having a suction plate 63b attached to the front end of the cassette 61, the alignment table 62, and the horizontal turning arm 63a of the first node is disposed around the recess 18 counterclockwise as viewed from above. The recovery arm 64 having the same structure as the supply arm 63, the horizontal turning arm 64a and the suction plate 64b, the spinner type cleaning device 65, and the cassette 66 are arranged.

  The cassette 61, the alignment table 62, and the supply arm 63 are means for supplying the substrate to the chuck table 15. The recovery arm 64, the cleaning device 65, and the cassette 66 are means for recovering the processed substrate from the chuck table 15. is there. Although the two cassettes 61 and 66 have the same structure, they will be referred to as a supply cassette 61 and a recovery cassette 66 according to applications. These cassettes 61 and 66 are for accommodating and carrying a plurality of substrates, and are set at predetermined positions on the base 11.

  A plurality of unprocessed substrates are accommodated in the supply cassette 61 in a stacked state. The transfer mechanism 60 has a function of taking out one substrate from the supply cassette 61 and placing it on the alignment table 62 by raising / lowering and turning the arm 60a and holding operation of the fork 60b.

  On the alignment table 62, the substrate is placed in a state determined at a certain position. The supply arm 63 sucks the substrate on the alignment table 62 to the suction plate (suction means) 63b, turns the arm 63a, places the substrate on the chuck table 15, and lowers the horizontal turning arm 63a. By stopping the suction operation, it has a function of placing the substrate on the chuck table 15.

  The recovery arm 64 has a function of sucking the processed substrate from the chuck table 15 onto the suction plate (suction means) 64b, turning the arm 64a, and transferring the substrate into the cleaning device 65. The cleaning device 65 has a function of rotating the substrate after the substrate is washed with water, and removing the water by shaking off the substrate. Then, the substrate cleaned by the cleaning device 65 is transferred and accommodated in the collection cassette 66 by the transfer mechanism 60.

  When the substrate is attached to or detached from the chuck table 15 by the supply arm 63 and the recovery arm 64, the movable table 14 is stopped at the substrate attachment / detachment position. In addition, a nozzle 67 that cleans the chuck table 15 by spraying high-pressure air onto the chuck table 15 is disposed between the supply arm 63 and the recovery arm 64. Cleaning of the chuck table 15 by the nozzle 67 is performed on the chuck table 15 at the substrate attachment / detachment position.

(Grinding device)
FIG. 3 shows an example of a grinding apparatus for grinding and flattening the surface of the substrate 601. A grinding apparatus 410 shown in FIG. 3 includes a base 411 on which various mechanisms are mounted. This base 411 is mainly composed of a rectangular parallelepiped portion having a horizontal upper surface, and has a wall portion 412 standing perpendicular to the upper surface at one end in the longitudinal direction (the end on the back side in FIG. 3). ing. In FIG. 3, the longitudinal direction, the width direction, and the vertical direction of the base 411 are indicated by a Y direction, an X direction, and a Z direction, respectively. The side of the base 411 from the substantially middle portion in the longitudinal direction to the wall 412 side is a grinding area 410A, and the opposite side supplies a substrate before grinding to the grinding area 410A and collects the substrate after grinding. 410B.

  A pit 411a, which is a shallow rectangular recess, is formed in the grinding area 410A on the upper surface of the base 411, and a disk-like shape in which the rotation axis is parallel to the Z direction and the upper surface is horizontal in the pit 411a. Turntable 413 is rotatably provided. This turntable 413 is rotated in the direction of arrow R by a rotation drive mechanism (not shown). A plurality of (three in this case) disk-shaped chuck tables 414 whose rotating shaft extends in the same Z direction as that of the turntable 413 and whose upper surface is horizontal are provided on the outer peripheral portion of the turntable 413. It is rotatably provided at equal intervals in the direction.

  The chuck table 414 is a generally known vacuum chuck type, and a substrate placed on the upper surface is sucked and held on the chuck table 414. Each chuck table 414 is independently rotated in one direction or both directions by a rotation drive mechanism (not shown) provided in the turntable 413.

  As shown in FIG. 3, in a state where two chuck tables 414 are arranged in the X direction on the wall 412 side, the rough grinding first is arranged immediately above the chuck table 414 in order from the upstream side in the rotation direction of the turn table 413. One grinding unit 420A and a second grinding unit 420B for finish grinding are provided. Each chuck table 414 is supplied / recovered most by the intermittent rotation of the turntable 413, the rough grinding position below the first grinding unit 420A, and the finish grinding position below the second grinding unit 420B. It is positioned at each of three positions with the attachment / detachment position approaching the area 410B.

  Since the grinding units 420A and 420B have the same configuration, they will be described with common reference numerals. The grinding units 420A and 420B are attached to the wall portion 412 of the base 411 so as to be movable up and down in the Z direction via a slider 431 and a guide rail 432, and are lifted and lowered by a lift drive mechanism 433. FIG. 4 is a perspective view (A) and a side view (B) showing an outline of a grinding unit portion. As shown in FIGS. 4A and 4B, when the spindle 422 incorporated in the cylindrical housing 421 is rotationally driven by the motor 423, the grinding units 420A and 420B have a flange 424 at the tip of the spindle 422. The cup wheel 425 fixed via the rotation rotates, and a large number of grindstones 426 fixed in an annular arrangement over the entire circumference of the outer peripheral portion of the lower surface of the cup wheel 425 grind the substrate 601. The outer diameter of the circular grinding locus of the grindstone 426 is approximately equal to the diameter of the substrate 601.

  The grinding units 420A and 420B are not coaxially arranged with respect to the chuck table 414 but are offset. Specifically, as shown in FIG. 4 (b), the center portion of the blade thickness (the length in the radial direction) of the blade edge of the many grindstones 426 arranged in an annular shape most inside the chuck table 414 is the chuck. The relative position is set so as to be positioned on a vertical line passing through the center of the table 414. Due to this positional relationship, when the surface of the substrate 601 is pressed by the grindstone 426 of the cup wheel 425 while rotating the substrate 601 together with the chuck table 414, the entire surface is ground. The cup wheel 425 is provided with a grinding water supply port (not shown) for supplying grinding water for cooling and lubrication or discharging grinding scraps to the workpiece below. The grinding units 420A and 420B are provided with a water supply line for supplying the grinding water to the grinding water supply port (not shown).

  As the grindstone 426, for example, diamond abrasive grains in which a grain size of about 50 μm and a grain size of about 5 μm are combined are used. For the cup wheel 425 of the first grinding unit 420A, a grindstone 26 for rough grinding having an abrasive grain size of about 50 μm is used, and for the cup wheel 425 of the second grinding unit 420B, abrasive grains are used. For finishing grinding with a diameter of about 5 μm is used. In the grinding units 420 </ b> A and 420 </ b> B configured as described above, the housing 421 is fixed to the slider 431 via the block 427.

  As shown in FIG. 3, in the pit 411a on the base 411, around the turntable 413 and closest to the supply / recovery area 410B, the cleaning water is discharged to the chuck table 414 at the attachment / detachment position. A cleaning nozzle 415 for cleaning the chuck table 414 is provided. In addition, a drain hole 416 for discharging water in the pit 411a to the outside is provided at one corner of the pit 411a on the wall 412 side.

  Next, the supply / recovery area 410B will be described. The supply / recovery area 410B is the same as the supply / recovery area 11B shown in FIG. Briefly, a two-barrel type transfer mechanism 460 that moves up and down in the center is provided, and a cassette 461 for supply and an alignment table are provided around the transfer mechanism 460 counterclockwise as viewed from above. 462, a swing arm type supply arm 463, a recovery arm 464 having the same structure as the supply arm 463, a spinner type cleaning device 465, and a recovery cassette 466 are arranged. The function of each means is the same as the supply / recovery area 11B shown in FIG.

(Step of flattening the substrate)
FIG. 5 is a cross-sectional view of the substrate illustrating an example of a process for planarizing the substrate 601. In this embodiment, a single crystal silicon wafer cut by a wire saw from a single crystal silicon ingot is processed as the substrate 601. First, a single crystal silicon ingot is cut with a wire saw to obtain a substrate 601 (FIG. 5A). When the substrate 601 is obtained, a polyolefin film is attached as a resin layer 602 to one surface thereof (FIG. 5B). The polyolefin film has a thickness of 60 μm and is coated with an adhesive on one side. Adhesion is performed by bringing the pressure-sensitive adhesive application surface into contact with the substrate 601 and applying pressure by a pressure difference due to vacuum or pressing by a roller or the like.

  When the substrate 601 shown in FIG. 5B on which the resin layer 602 is formed is obtained, it is stored in the cassette 61 of the cutting apparatus 10 shown in FIG. 1 with the surface of the resin layer 602 facing up. In cutting the resin layer 602 using the cutting device 10, first, the substrate 601 is taken out from the cassette 61 by the transfer mechanism 60, placed on the alignment table 62, and positioned. The positioned substrate 601 is adsorbed by the adsorption plate 63b of the supply arm 63 and transferred onto the chuck table 15 that has been moved to the supply / recovery area 11B side with the resin layer 602 exposed on the upper surface. Placed on. In this mounted state, suction is performed from a vacuum hole 15 c provided in the chuck table 15, and the substrate 601 is sucked and fixed to the chuck table 15. FIG. 2A shows a state where the substrate 601 is attracted and fixed to the chuck table 15. That is, the substrate 601 is fitted into the recess 15a provided in the chuck table 15, and in this state, a vacuum device (not shown) is operated to perform suction from the vacuum hole 15c. Since the substrate 601 is supported by the support portions 15d on the three cones, the gap between the bottom surface 15b of the recess 15a and the surface of the substrate 601 facing the substrate 601 is in a reduced pressure state, and the substrate is subjected to a pressure difference from the atmospheric pressure. 601 is pressed and fixed to the support portion 15d side.

  In FIG. 1, the chuck table 15 on which the substrate 601 is fixed by suction is transferred in the Y-axis direction to the front of the wheel mount 25. Next, the wheel mount 25 is rotated at about 2000 rpm, and the position in the Z-axis direction is adjusted so that the depth of cutting per one time with respect to the resin layer 602 is about 1 to 10 μm. Then, the chuck table 15 is fed in the direction of the wall 12 along the Y axis at a feed rate of 0.1 to 1 mm per second. Thereby, the resin layer 602 adhered to the substrate 601 by the cutting tool 26 is cut. FIG. 6 is a conceptual diagram showing how the surface of the resin layer 602 is cut by the cutting tool 26. As shown in FIG. 6, the substrate 601 is supported on the chuck table 15 by a conical support portion 15d, and is adsorbed and fixed by evacuation in the recess 15a. Further, in a state where the substrate 601 is adsorbed and fixed, the surface layer of the resin layer 602 is cut by the cutting tool 26 to form a flat surface 602b.

  In this way, as shown in FIG. 5C, the wavy surface 602a of the resin layer 602 is flattened by cutting to form a flat surface 602b. When the flat surface 602b shown in FIG. 5C is formed, the chuck table 15 is moved to the supply / recovery area 11B side, and the suction fixed state of the chuck table 15 is released. Then, the substrate 601 is recovered from the chuck table 15 by the suction plate 64b of the recovery arm 64 and transferred to the cleaning device 65. In the cleaning device 65, the cutting surface is cleaned and dried. The substrate 601 that has been cleaned and dried is stored in the cassette 66 by the function of the transfer mechanism 60.

  After the process shown in FIG. 5C is completed, the substrate 601 is ground using the grinding apparatus 410 shown in FIG. First, the substrate 601 after the processing of FIG. 5C is stored in the supply cassette 461 shown in FIG. 3 with the resin layer 602 facing down. The substrate 601 accommodated in the supply cassette 461 is transferred to the alignment table 462 by the transfer mechanism 460, where alignment is performed. The substrate 601 that has been aligned is placed on the chuck table 414 that is waiting at the attachment / detachment position and in which the vacuum apparatus is operated, by the supply arm 463. FIG. 5D shows this state. In this state, the flattened resin layer 602 is in contact with the chuck table 414, and the surface of the substrate 601 with waviness is exposed on the surface.

  Next, the turntable 413 rotates in the direction of arrow R in FIG. 3, and the chuck table 414 holding the substrate 601 stops at the rough grinding position. At this time, the next chuck table 414 is positioned at the attachment / detachment position, and the substrate 601 to be ground next is set on the chuck table 414 as described above. Then, the chuck table 414 at the rough grinding position is rotated to rotate the substrate 601, while the cup wheel 425 (see FIG. 4) of the first grinding unit 420A for rough grinding is rotated and the cup wheel is rotated. While supplying the predetermined grinding water from the grinding water supply port 425, it is slowly lowered at a predetermined speed, and the grindstone 426 is pressed against the surface of the substrate 601 to start rough grinding. When the rough grinding is finished, the first grinding unit 420A is raised.

  Subsequently, the substrate 601 that has been subjected to the rough grinding is transferred to the finish grinding position by rotating the turntable 413 in the R direction. Here, the chuck table 414 is rotated in the same manner as described above, and the finish grinding first step is performed. By using the second grinding unit 420B, the exposed surface of the substrate 601 is finish-ground. By this two-stage grinding, the state shown in FIG. 5E is obtained from the state shown in FIG. That is, the wavy surface 601a of the substrate 601 is ground to form a flat surface 601b.

  The next substrate 601 that has been set in the attach / detach position in advance is transferred to the rough grinding position, and this substrate 601 is coarsely ground in the same manner as described above in parallel with the preceding finish grinding. Further, the substrate 601 to be processed next is set on the chuck table 414 moved to the attachment / detachment position.

  Here, examples of suitable operating conditions for the above rough grinding and finish grinding will be given. In both the first and second grinding units 420A and 420B, the rotational speed of the cup wheel 425 is 3000 to 5000 RPM, and the rotational speed of the chuck table 414 is 100 to 300 RPM. The lowering speed, which is the grinding feed speed of the first grinding unit 420A for rough grinding, is 3 to 5 μm / second, and the lowering speed of the second grinding unit 420B for finish grinding is 0.3 to 1 μm / second. .

  When both finish grinding and rough grinding, which have been performed in parallel, are finished, the turntable 413 is rotated, and the substrate 601 after finish grinding is transferred to the attachment / detachment position. As a result, the subsequent substrate 601 is transferred to the rough grinding position and the finish grinding position, respectively. The substrate 601 on the chuck table 414 positioned at the attachment / detachment position is transferred to the cleaning device 465 by the recovery arm 464, and is washed and dried. Then, the substrate 601 cleaned by the cleaning device 465 is transferred and accommodated in the cassette 466 by the transfer robot 460.

  The above is a cycle in which one surface of a single substrate 601 having a surface waviness is flattened by grinding, washed, and recovered. In this flattening process, since the flattened resin layer 601 is provided on the surface of the substrate 601 in contact with the chuck table 414, the substrate 601 is held on the chuck table 414 using the flat surface as a reference surface. Is done. For this reason, as shown in FIG. 5D, even if the front and back surfaces of the substrate 601 are wavy, it does not adversely affect the holding state of the substrate 601 on the chuck table 414. Then, high flatness of the exposed surface of the substrate 601 shown in FIG.

  The substrate 601 after the step shown in FIG. 5E is taken out from the grinding apparatus 410 shown in FIG. Then, the front and back of the substrate 601 are reversed to obtain the state shown in FIG. 5F, and the resin layer 602 is removed. In this case, the resin layer 602 is heated and softened, and the resin layer 602 is melted and peeled using a special release agent. In this way, the state shown in FIG. Alternatively, a strong adhesive tape can be attached to the surface of the substrate 601 and cut, and then peeled off. Further, a strong adhesive tape for peeling can be attached to the surface of the film-like one, and the strong adhesive tape for peeling can be pulled in a direction opposite to the substrate 601 to peel the film-like one.

  Next, with the undulating surface facing up (state of FIG. 5 (G)), the substrate 601 is set in the grinding apparatus shown in FIG. 3, and in the same manner as shown in FIG. 5 (E), Grind the surface where waviness occurs and flatten the surface. By this grinding, as shown in FIG. 5H, a wavy surface 601c is ground, and a flat surface 601d is obtained. At this time, since one surface of the substrate 601 is flattened in the step of FIG. 5E, the surface 601c where the waviness remains is ground using that surface as a reference surface. For this reason, high flatness can be obtained. In this way, a substrate 601 having a flat front and back is obtained.

2. Other Embodiments As a method of forming the resin layer 602, a method of applying a solution-like resin material using a spin coater and solidifying by heating or ultraviolet curing may be employed. The method of forming the resin layer 602 using the spin coating method has an advantage that the thickness of the resin layer 602 can be easily controlled by adjusting the viscosity of the solution to be applied and the spin coating conditions. In addition, by adjusting the viscosity of the solution to be spin-coated, a certain level of flattening effect due to surface tension can be obtained.

  Further, as a method of removing the resin layer 602 at the stage of moving from FIG. 5F to FIG. 5G, the resin layer 602 may be ground and removed by a grinding apparatus shown in FIG. In this case, following the removal of the resin layer 602 by grinding, the remaining surface of the substrate 601 where the waviness remains can be ground to obtain a flat surface 601d shown in FIG.

  INDUSTRIAL APPLICABILITY The present invention can be used in a technique for removing unevenness remaining on the surface of a single crystal silicon wafer cut from an ingot and flattening it. The present invention is not limited to a single crystal silicon wafer, and can be used for a technique for planarizing a plate-like semiconductor material or metal material.

It is a perspective view which shows an example of the cutting device utilized when implementing invention. It is the side view (A) and top view (B) which show the structure of the chuck table vicinity of the cutting device shown in FIG. It is a perspective view which shows an example of the grinding device utilized when implementing invention. It is the perspective view (A) and side view (B) which show the outline | summary of a grinding unit part. It is process sectional drawing which shows an example of the process of planarizing a board | substrate using invention. It is a conceptual diagram which shows a mode that the surface of the resin layer by a cutting tool is cut. It is a conceptual diagram which shows the method of obtaining a board | substrate from the ingot in a prior art.

Explanation of symbols

  601... Substrate (single crystal silicon wafer), 601 a. ... surface with undulation, 602b ... surface flattened by cutting.

Claims (4)

A method for flatly processing a substrate cut out from an ingot,
Forming a resin layer on one surface of the substrate;
Cutting the resin layer;
Adsorbing and fixing the surface of the cut resin layer and grinding the other surface of the substrate;
A method of processing a substrate, comprising: adsorbing and fixing the other surface that has been ground and grinding the one surface of the substrate.   The substrate processing method according to claim 1, wherein in the step of cutting the resin layer, the other surface of the substrate is fixed by at least three points of support.   The substrate processing method according to claim 1, wherein the resin layer is formed by sticking a resin film or applying a solidifying material to solidify the resin layer.   The substrate processing method according to claim 1, wherein the resin layer is removed before the one surface is ground.

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