JP4916995B2 - Wafer cleaning device and grinding device - Google Patents

Description

  The present invention relates to an apparatus for cleaning the back surface of a wafer such as a semiconductor wafer having a recess formed on the back surface by grinding, and a grinding apparatus equipped with the cleaning apparatus.

  Semiconductor devices have been required to be thinner in response to demands for light and thin electronic devices to be mounted, and semiconductor wafers have been thinned accordingly. Thinning of a semiconductor wafer is generally performed by grinding the back surface of the semiconductor wafer. For example, when performing an additional process such as attaching a metal film to the back surface of the wafer after thinning, the wafer machine There is a risk of cracking due to insufficient strength. Therefore, a technique is known in which only a device formation region is thinned by grinding a region on the back surface corresponding to a device formation region in which a semiconductor device is formed on the front surface (see Patent Document 1, etc.). In this way, the wafer in which only the device formation region is thinned has a recess formed on the back surface, and an annular protrusion protruding to the back surface is formed on the outer periphery around the recess with the original thickness remaining. . And since an annular convex part becomes a reinforcement part and rigidity is ensured, the said additional process can be implemented safely and appropriately.

JP 2007-19379 A

  By the way, the wafer after grinding is cleaned to remove grinding debris, and as a cleaning method, the wafer is placed on a vacuum suction type spinner table with the back side facing up and rotated together with the spinner table. There is a method in which cleaning water such as pure water is supplied to the back surface. When this method is applied to a wafer in which a recess is formed on the back surface and the device formation region is processed extremely thin as described above, the size of the spinner table depends on the device formation region where the recess is formed and the periphery of the recess. It is necessary to have a size on which the annular convex portion is placed, that is, a size equivalent to the outer diameter of the wafer or a size larger than the outer diameter (herein referred to as a full surface mounting type). This is because when only a thin device formation region is placed, the device formation region may be damaged due to stress by the suction force of vacuum suction.

  After placing and cleaning a wafer with a recess formed on the back surface of a spinner table of such size, the wafer is taken up from the spinner table to be transferred to the next process and transported to a predetermined transport destination. Yes. In various devices for processing and processing wafers in recent years, automation has become widespread, and the same is true for wafer conveyance, and automatic conveyance means such as a vacuum suction robot hand is used. However, a general robot hand does not have a structure for adsorbing and holding an uneven and uneven surface like a wafer having a recess formed on the back surface. Further, since the wafer placed on the above-described full-mount type spinner table does not have a portion protruding from the spinner table, the protruding portion can be held in the thickness direction or adsorbed on the back surface. Have difficulty. Even if a special mechanism is added to the robot hand to hold the wafer with the recesses, the wafer picked up from the spinner table needs to be accommodated in a cassette having a slot in which a large number of wafers are stacked. . However, since the slot is made thin corresponding to the wafer, it is difficult to properly accommodate the wafer in such a thin slot if the special mechanism as described above is added.

  Therefore, the present invention holds the wafer on the entire surface-mounted spinner table with the back surface where the recess is formed exposed, and then cleans the wafer safely and surely to a predetermined transfer destination. It is an object of the present invention to provide a cleaning device that can be transported to the surface and a grinding device equipped with such a cleaning device.

  The cleaning apparatus of the present invention described in claim 1 has a substantially circular device forming region having a plurality of devices formed on the surface, and an outer peripheral surplus region surrounding the device forming region. An apparatus for cleaning the back side of a wafer in which a corresponding back side region is ground to a predetermined thickness and formed a recess, having a holding surface equivalent to the wafer outer diameter or larger than the wafer outer diameter, A holding means for holding the wafer in a state where the back surface is exposed on the holding surface, a cleaning means for cleaning the back surface of the wafer held by the holding means, and a peripheral excess area of the wafer whose back surface is cleaned by the cleaning means. Holding and picking up and holding the vicinity of the outer peripheral surplus area on the front side of the wafer held by the first transfer means, and the first transfer means for picking up the wafer from the holding means and exposing the surface side. The given It is characterized in that it comprises a second conveying means for conveying the Okusaki.

  According to the cleaning apparatus of the present invention, the wafer is placed and held on the holding means (corresponding to the spinner table) with the back surface where the concave portion and the annular convex portion are formed exposed. The holding means has a holding surface corresponding to the outer diameter of the wafer or larger than the outer diameter of the wafer, and the wafer is mounted on the holding surface. The wafer held by the holding unit is first cleaned by the cleaning unit, and after cleaning, is taken up from the holding unit by the first transfer unit, and then transferred to a predetermined transfer destination by the second transfer unit.

  The first transfer means holds the outer peripheral surplus area of the wafer and picks up the wafer from the holding means. At this stage, the front side of the wafer is exposed. Since the first transfer means holds not the thin device formation region corresponding to the concave portion of the wafer but the outer peripheral surplus region, that is, the annular convex portion serving as the reinforcing portion, the wafer is safely transferred without being damaged. Next, the 2nd conveyance means which conveys a wafer adsorb | sucks and hold | maintains the part corresponding to at least the outer peripheral surplus area | region of the surface side to expose, and conveys it to a predetermined conveyance destination. Even in the second transfer means, the vicinity of the outer peripheral surplus area of the wafer is attracted and held, so that the wafer can be safely transferred without being damaged. Since the second transport means is configured to suck and hold the front surface side of the wafer, it can be formed of a thin member. For this reason, the wafer is accommodated in a cassette having a slot in which a large number of wafers are stacked. be able to.

  Next, the grinding device of the present invention described in claim 2 includes a grinding means for forming a recess on the back surface of the wafer, and also includes the cleaning device according to claim 1, wherein the recess is formed on the back surface. The cleaning of the back surface where the recesses are formed can be carried out continuously by a series of operations. That is, the grinding apparatus of the present invention is a back surface side corresponding to a device forming region of a wafer having a substantially circular device forming region having a plurality of devices formed on the surface and an outer peripheral surplus region surrounding the device forming region. A grinding apparatus for grinding a region of a predetermined thickness to form a recess, and a processing holding means having a holding surface for holding the wafer in a state where the back surface of the wafer is exposed, and held by the holding surface A grinding means for grinding a region corresponding to a device formation region of the wafer to form a recess, a cleaning device for cleaning the back surface of the wafer having a recess formed on the back surface by the grinding device, and a recess on the back surface by the grinding means. The cleaning apparatus is characterized in that the cleaning apparatus is a cleaning apparatus according to claim 1, wherein the cleaning apparatus is provided with a transfer means for holding an outer peripheral surplus area of the wafer on which the wafer is formed and transferring it to the cleaning apparatus.

  According to the present invention, the wafer can be safely and reliably picked up and smoothly transferred to a predetermined transfer destination after the wafer is cleaned with the back surface where the concave portion is formed exposed. There are effects such as.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[1] Semiconductor wafer Reference numeral 1 in FIG. 1 is a disk-shaped semiconductor wafer which is a product to be processed in the present embodiment. The wafer 1 is a silicon wafer or the like, and a plurality of rectangular semiconductor chips (devices) 3 are partitioned on a surface 1 a by grid-like division lines 2. An electronic circuit (not shown) such as an IC or an LSI is formed on the surface of the semiconductor chip 3.

  The plurality of semiconductor chips 3 are formed in a substantially circular device formation region 4 concentric with the wafer 1. The device forming region 4 occupies most of the wafer 1, and the outer periphery of the wafer 1 around the device forming region 4 is an annular outer peripheral region 5 in which the semiconductor chip 3 is not formed. A V-shaped notch 6 indicating a semiconductor crystal orientation is formed at a predetermined location on the outer peripheral surface of the wafer 1. The notch 6 is formed in the outer peripheral surplus region 5.

  The thickness of the wafer 1 is, for example, about 700 μm. As shown in FIG. 2, the wafer 1 has only a predetermined thickness removed from the area corresponding to the device formation area 4 on the back surface 1b to form a recess 4A. An annular convex portion 5A in which the original thickness remains in the outer peripheral surplus region 5 around the concave portion 4A is formed. By forming the recess 4A, the device formation region 4 is thinned to the thickness of the semiconductor chip 3 to be obtained (for example, about 50 to 100 μm). The formation of the recess 4A on the back surface of the wafer is performed by grinding in this case, and FIG. 3 shows an example of a grinding apparatus suitable for performing grinding.

  Hereinafter, the configuration and operation of the grinding apparatus 20 will be described. Before the wafer 1 is supplied to the grinding apparatus 20, a protective tape is formed on the entire surface 1a on which the semiconductor chip 3 is formed for the purpose of protecting electronic circuits. 7 is attached. For example, the protective tape 7 has a structure in which an adhesive of about 5 to 20 μm is applied to one side of a soft resin base sheet such as polyolefin having a thickness of about 70 to 200 μm, and the adhesive is used as the surface 1 a of the wafer 1. It is pasted according to.

[2] Grinding device The grinding device 20 will be described with reference to FIGS. According to this grinding apparatus 20, the surface 1 a side of the wafer 1 is attracted to the vacuum suction type chuck table (processing holding means) 30 via the protective tape 7 to hold the wafer 1, and two grinding units (For rough grinding and finish grinding) 40A and 40B form the concave portion 4A on the back surface 1b and finish the bottom surface of the concave portion 4A flat.

The configuration and operation of the grinding apparatus 20 are as follows.
As shown in FIG. 3, the grinding apparatus 20 has a rectangular parallelepiped base 21, and the wafer 1 is placed on a surface 1 a in a supply cassette 22 </ b> A that is detachably set at a predetermined position on the base 21. A plurality is accommodated with the side up. In the supply cassette 22A, slots for accommodating one wafer 1 are arranged in the vertical direction, and a plurality of wafers 1 are stacked and accommodated in the vertical direction. The partition members of the slots are provided in multiple stages on both sides in the cassette 22A, and the interval between the partition members, that is, the width of the slots is, for example, about 10 mm. One wafer 1 accommodated in the supply cassette 22A is pulled out by a transfer robot (second transfer means) 23, turned upside down, and placed on the positioning table 24 with the back surface 1b facing up. Here, the position is fixed.

  In the transfer robot 23, an articulated arm 23b is mounted on a rotary shaft 23a extending in the vertical direction and extending in the vertical direction so as to be able to turn horizontally, and a vacuum suction type robot pick having a flat plate fork shape at the tip of the arm 23b. 23c is attached. The robot pick 23c has a vacuum suction surface on one side. The robot pick 23c is inserted into the lower surface side (in this case, the back surface 1b side) of the wafer 1 with the suction surface facing upward, and then the wafer 1 is received. Adsorb and hold in a wet state. The robot pick 23c can be moved to a desired location by the operation of the rotating shaft 23a and the arm 23b, and is inserted into the supply cassette 22A so that the lower surface of the wafer 1 accommodated in the slot can be sucked. It has become.

  A turntable 35 that is rotationally driven in the R direction is provided on the base 21, and a plurality of (in this case, three) disk-shaped chuck tables 30 are provided on the outer periphery of the turntable 35. Are arranged at equal intervals in the circumferential direction. These chuck tables 30 are rotatably supported with the Z direction (vertical direction) as a rotation axis, and are driven to rotate by a drive mechanism (not shown).

  The wafer 1 positioned on the positioning table 24 is picked up from the positioning table 24 by the supply arm 25, and the surface 1a side on which the protective tape 7 is adhered is lowered on one chuck table 30 which is vacuum operated. It is placed concentrically in the state of facing. The supply arm 25 is configured such that an arm 25b is supported on the base 21 via a turning shaft 25a so that the arm 25b can be turned horizontally, and a vacuum suction type suction pad 25c is attached to the tip of the arm 25b. The wafer 1 is sucked and held on the lower surface of the suction pad 25 c and transferred from the positioning table 24 to the chuck table 30.

  As shown in FIG. 4B, the chuck table 30 is formed by forming a circular suction portion 32 made of a porous member at the center upper portion of the frame body 31, and the wafer 1 is placed on the upper surface 32 a of the suction portion 32. It is adsorbed and held in a state where the protective tape 7 is in close contact and the back surface 1b is exposed upward. For this reason, the electronic circuit of the semiconductor chip 3 on the surface 1 a side of the wafer 1 is protected by the protective tape 7 and is prevented from being damaged from the chuck table 30.

  The wafer 1 held on the chuck table 30 is fed to a primary processing position below the rough grinding unit 40A when the turntable 35 rotates by a predetermined angle in the R direction (clockwise direction), and is ground at this position. The back surface 1b is roughly ground by the unit 40A to form the recess 4A. Next, the turntable 35 is again rotated by a predetermined angle in the R direction to feed the wafer 1 to a secondary machining position below the finish grinding unit 40B. At this position, the bottom surface of the recess 4A is finished by the grinding unit 40B. To be ground.

  Each of the grinding units 40A and 40B has the same configuration, and is distinguished by the fact that the grindstones to be mounted are different for rough grinding and finish grinding. As shown in FIG. 4, the grinding units 40A and 40B include a cylindrical spindle housing 41 whose axial direction extends in the Z direction, and a spindle shaft 42 that is coaxially and rotatably supported in the spindle housing 41. A motor 43 that is fixed to the upper end of the spindle housing 41 and rotationally drives the spindle shaft 42 and a flange 44 that is coaxially fixed to the lower end of the spindle shaft 42 are provided. A grindstone wheel 45 is detachably attached to the flange 44.

  The grindstone wheel 45 is composed of a frame 46 formed in a conical shape whose diameter is reduced as the lower part is directed downward, and a plurality of grindstones 47 that are annularly fixed and arranged on the lower surface of the frame 46. The grinding wheel outer diameter of the grinding wheel 45 (the diameter of the outer peripheral edge of the plurality of grinding wheels 47 arranged in an annular shape) is a dimension corresponding to the radius of the recess 4A formed on the back surface 1b of the wafer 1, that is, the radius of the device formation region 4. It has become. The cutting edge surface which is the lower end surface of the grindstone 47 is set so as to be orthogonal to the axial direction of the spindle shaft 42. As the grindstone 47, for example, a material obtained by mixing, molding, and sintering diamond abrasive grains in a glassy bond material is used.

  The grindstone 47 fixed to the grindstone wheel 45 is for rough grinding and finish grinding, and the grindstone wheel 45 for which the grindstone 47 is for rough grinding is mounted on a grinding unit 40A for rough grinding. Further, the grindstone wheel 45 in which the grindstone 47 is used for finish grinding is mounted on a grinding unit 40B for finish grinding. As the grinding wheel 47 for rough grinding, for example, one containing relatively coarse abrasive grains of about # 320 to # 600 is used. Further, as the grindstone 47 attached to the grinding unit 40B for finish grinding, for example, a grindstone containing relatively fine abrasive grains of about # 2000 to # 8000 is used. Each of the grinding units 40A and 40B is provided with a grinding water supply mechanism (not shown) for supplying grinding water for cooling and lubrication of the grinding surface or discharging grinding debris.

  As shown in FIG. 3, each of the grinding units 40 </ b> A and 40 </ b> B is attached to the front surface of a pair of left and right columns 26 arranged in the X direction that is erected at the end of the base 21 on the far side in the Y direction. The mounting structure of each grinding unit 40A, 40B with respect to each column 26 is the same and is symmetrical in the X direction.

  The front surface 26a on the front side in the Y direction of each column 26 is a vertical surface with respect to the upper surface of the base 21, but tapers back obliquely at a predetermined angle from the center in the X direction toward the end. Formed on the surface. The horizontal direction of the taper surface 26a, that is, the taper direction, is the position of the chuck table 30 positioned at the corresponding front machining position (the left primary machining position in the left column 26 and the right secondary machining position in the right column 26). It is set to be parallel to a line connecting the rotation center and the rotation center of the turntable 35.

  As shown in FIGS. 4 and 5, the taper surface 26 a of each column 26 is provided with a pair of upper and lower guides 51 parallel to the taper direction, and the X-axis slider 52 slides on the guides 51. It is installed freely. The X-axis slider 52 is reciprocated along the guide 51 by a ball screw type feed mechanism (not shown) driven by a servo motor 53. The reciprocating direction of the X-axis slider 52 is parallel to the direction in which the guide 51 extends, that is, the taper direction of the tapered surface 26a.

  The front surface of the X-axis slider 52 is a surface along the X / Z direction, and the grinding units 40A and 40B are installed on the front surface so as to be movable up and down in the Z direction (vertical direction). These grinding units 40 </ b> A and 40 </ b> B are slidably mounted via a Z-axis slider 55 on a guide 54 that extends in the Z direction and is provided on the front surface of the X-axis slider 52. Each grinding unit 40A, 40B is moved up and down in the Z direction via a Z-axis slider 55 by a ball screw type feed mechanism 57 driven by a servo motor 56.

  As described above, the direction connecting the rotation center of each chuck table 30 positioned at the primary processing position and the secondary processing position and the rotation center of the turntable 35 (the direction indicated by arrow F in FIG. Are referred to as the taper direction of the front surface 26a of the column 26, that is, the direction in which the guide 51 extends. In each grinding unit 40A, 40B, the center of rotation of the grinding wheel 45 (axial center of the spindle shaft 42) corresponds to the machining position (primary machining position in the grinding unit 40A for rough grinding, and in the grinding unit 40B for finishing). The positions are set so as to exist directly in the inter-axis direction connecting the rotation center of the chuck table 30 and the rotation center of the turntable 35 positioned at the secondary processing position). Therefore, when the grinding units 40A and 40B move along the guide 51 together with the X-axis slider 52, the rotation center of the grinding wheel 45 is set to move along the inter-axis direction.

  In forming the recess 4A by grinding only the region corresponding to the device formation region 4 on the back surface 1b of the wafer 1, the position between the axes of the grinding unit 40A (40B) is as shown in FIGS. The grinding outer diameter of the grindstone wheel 45 facing the back surface 1 b of the wafer 1 positioned at each processing position is positioned at a recess forming position corresponding to the radius of the device forming region 4 of the wafer 1. This recess formation position is a position where the cutting edge surface of the grindstone 47 passes near the rotation center of the wafer 1 and the outer peripheral edge of the device formation region 4, and in this case, the outer peripheral side of the turntable 35 with respect to the rotation center of the wafer 1. The

  When the axial direction of the grinding unit 40A (40B) is determined in this way, the chuck table 30 is rotated to rotate the wafer 1, and the feed unit 57 rotates while feeding the grinding unit 40A (40B) downward. A grinding operation for pressing the grinding wheel 47 of the grinding wheel 45 against the back surface 1b of the wafer 1 is started.

  By rough grinding by the grinding unit 40A at the primary processing position, a recess 4A is formed on the back surface 1b of the wafer 1 in a region corresponding to the device formation region 4 as shown in FIG. 2, and an annular shape is formed around the recess 4A. A convex portion 5A is formed. Further, the bottom surface of the recess 4A is finish-ground by finish grinding by the grinding unit 40B at the secondary processing position. In the rough grinding, for example, the thickness after finish grinding is ground to a thickness of about 20 to 40 μm, and in the finish grinding, the remaining thickness is ground, whereby the thickness of the semiconductor chip 3 to obtain a region corresponding to the device formation region 4 is obtained. It is thinned.

  As shown in FIG. 2 and FIG. 4A, the grinding striations 9 having a pattern in which a large number of arcs are radially drawn remain on the surface to be ground after rough grinding. The grinding striation 9 is a trajectory of crushing processing by abrasive grains in the grindstone 47 and is a mechanical damage layer including microcracks and the like. Although the grinding striation 9 by rough grinding is removed by finish grinding, a new grinding striation may remain even by finish grinding.

  When grinding the wafer 1, in both rough grinding and finish grinding, the wafer thickness is measured one after another by a contact-type thickness measuring device 60 provided in the vicinity of each processing position, and based on the measured value. The grinding amount is controlled. As shown in FIG. 4A, the thickness measuring device 60 is configured by a combination of a reference side height gauge 61 and a movable side height gauge 62.

  Each of the height gauges 61 and 62 is provided with probes 61 a and 62 a, the probe 61 a of the reference side height gauge 61 contacts the surface 31 a of the frame 31 of the chuck table 30, and the probe 62 a of the movable side height gauge 62 is covered with the wafer 1. It is set so as to contact the grinding surface. The thickness measuring device 60 outputs the measured thickness value of the wafer 1 by comparing the height positions of the contact points of the probes 61a and 62a. The measurement point when the thickness of the device formation region 4 is measured by forming the recess 4A, that is, the contact point of the probe 61a of the movable height gauge 61 is the outer periphery of the recess 4A as shown by the broken line in FIG. Part is preferred.

  The wafer 1 in which the formation of the recess 4A is completed by grinding is collected as follows. First, the finishing grinding unit 40B is raised and retracted from the wafer 1, while the turntable 35 is rotated by a predetermined angle in the R direction so that the wafer 1 is mounted on the chuck table 30 from the supply arm 25. Return to position. The vacuum operation of the chuck table 30 is stopped at this attachment / detachment position, and then the wafer 1 is transferred to the spinner type cleaning device 70 by the recovery arm (transfer means) 27 and cleaned.

  The recovery arm 27 is the same as the supply arm 25 that transfers the wafer 1 to the chuck table 30 and is arranged in parallel with the supply arm 25. That is, the recovery arm 27 is configured such that the arm 27b is supported on the base 21 via a turning shaft 27a so that the arm 27b can turn horizontally, and a vacuum suction suction pad 27c is attached to the tip of the arm 27b. The outer diameter of the suction pad 27c corresponds to the outer diameter of the wafer 1 or is set to be slightly larger, and an annular suction formed by forming an air suction port on the entire outer periphery of the lower surface of the suction pad 27c. The part is formed. This suction portion has substantially the same diameter and width as the annular convex portion 5 </ b> A formed on the wafer 1. The upper surface of the annular convex portion 5A protruding upward is attracted to the suction portion of the suction pad 27c that is operated in a vacuum, and the wafer 1 is transferred from the chuck table 30 to the cleaning device 70 by the turning operation of the arm 27b.

  As shown in FIGS. 7 and 8, the cleaning device 70 includes a vacuum adsorption spinner table (holding means) 71 disposed in a pit 21 a provided on the upper surface of the base 21, and a cleaning water supply mechanism ( (Cleaning means) 80, a wafer pick-up mechanism (first transfer means) 90, and a cover 79 that covers these components and prevents splashing of cleaning water. The spinner table 71 has a disk shape with an outer diameter slightly larger than the outer diameter of the wafer 1 and is supported rotatably about the Z direction (vertical direction) as a rotation axis, and is rotated by a drive mechanism (not shown). . As shown in FIG. 8A, an adsorption portion 71b made of a porous member is formed on the upper surface (holding surface) 71a of the spinner table 71, and the wafer 1 conveyed by the recovery arm 27 is recessed 4A. In a state where the back surface 1b side where the is formed is exposed, it is placed concentrically on the suction portion 71b, and is sucked and held by vacuum operation. An opening for allowing the collection arm 27 to enter the cover 79 is provided at a predetermined position of the cover 79, and the opening is appropriately opened and closed by a shutter.

  The cleaning water supply mechanism 80 includes a nozzle stand 81 erected on the base 21 and a nozzle arm 84 that is mounted on the nozzle stand 81 through a nozzle base 82 so as to be horizontally rotatable and has a nozzle 83 at the tip and extends in the horizontal direction. It consists of The nozzle arm 84 is located above the spinner table 71 and reciprocates between a retracted position outside the spinner table 71 shown in FIG. 7 and a cleaning position where the nozzle 83 is positioned immediately above the rotation center of the spinner table 71. Turn. A cleaning water supply source (not shown) is provided inside the base 21, and cleaning water such as pure water is supplied from the cleaning water supply source to the nozzle 83 through the nozzle stand 81, the nozzle base 82, and the nozzle arm 84. Pumped.

  The wafer 1 is cleaned by rotating the spinner table 71 at about 1000 rpm and rotating the wafer 1, the nozzle arm 84 of the cleaning water supply mechanism 80 is positioned at the cleaning position, and the cleaning water is dripped from the nozzle 83. . The cleaning water is dropped near the center of the concave portion 4A of the wafer 1 and spreads around, and flows and drains from the concave portion 4A to the annular convex portion 5A. During that time, grinding waste and the like are washed away by the cleaning water. Next, while the rotation speed of the spinner table 71 is increased to about 2000 to 3000 rpm, dry air is sprayed from the nozzle 83 to the back surface 1b of the wafer 1 instead of the cleaning water, and is dried.

  The dried wafer 1 is then picked up from the spinner table 71 by the wafer picking mechanism 90, and the surface 1a side which is the bottom surface is exposed. As shown in FIGS. 7 and 8, the wafer take-up mechanism 90 is erected on a base 21 via a cylinder 91, and a stand 92 provided so as to advance and retreat in the vertical direction by the cylinder 91. The arm 93 is fixed to the upper end and extends horizontally above the spinner table 71, and the suction pad 94 is fixed horizontally to the tip of the arm 93 and disposed above the spinner table 71.

  The suction pad 94 is the same as the suction pad 27c of the recovery arm 27, and the outer diameter corresponds to the outer diameter of the wafer 1 or is set slightly larger. As shown in FIG. An annular suction portion 94a in which air suction ports are formed over the entire circumference is formed on the outer peripheral portion of the lower surface (shaded portion). The suction portion 94a has substantially the same diameter and width as the annular convex portion 5A formed on the wafer 1. The suction pad 94 is fixed to the arm 93 so as to be concentric with the spinner table 71. The suction pad 94 is moved up and down between the retracted position away from the wafer 1 (position of the suction pad 94 in FIG. 8A) and the suction position where the suction portion 94a contacts the annular convex portion 5A by the cylinder 91. . The nozzle arm 84 of the cleaning water supply mechanism 80 rotates in the space between the suction pad 94 at the retracted position and the wafer 1 held by the spinner table 71, and the suction pad 94 is at the retracted position when cleaning the wafer 1. Positioned on.

  According to the wafer picking mechanism 90, the suction pad 94 is operated in a vacuum at a stage where it is in the retracted position shown in FIG. 9A, and then the suction pad 94 is lowered by the cylinder 91 as shown in FIG. The suction portion 94a comes into contact with the upper surface of the annular convex portion 5A of the wafer 1 which has been cleaned with the cleaning water and dried. As a result, the annular protrusion 5A of the wafer 1 is adsorbed by the adsorbing portion 94a, and then the adsorbing pad 94 rises to the retracted position as shown in FIG. 9C. The wafer 1 is lifted while being sucked by the suction pad 94 and is separated from the spinner table 71, so that the surface 1a side of the wafer 1 to which the protective tape 7 is stuck is exposed.

  Next, the wafer 1 is transferred and accommodated in the collection cassette 22B by the transfer robot 23 as follows. First, as shown in FIG. 9 (d), the robot pick 23 c of the transfer robot 23 operated in vacuum enters the lower surface side of the wafer 1. Next, the vacuum operation of the suction pad 94 is stopped, whereby the wafer 1 is received by the robot pick 23c, and is sucked and held. The length of the robot pick 23c is sufficiently longer than the diameter of the wafer 1, so that the wafer 1 is in a state where the annular protrusion 5A is supported by the robot pick 23c.

  The robot pick 23c holding the wafer 1 moves downward as shown in FIG. 9 (e), and then the arm 23b operates appropriately so that the robot pick 23c enters the collection cassette 22B and accommodates the wafer 1. The recovery cassette 22B has the same configuration as the supply cassette 22A. When the wafer 1 is inserted into the slot in which the wafer 1 is accommodated and the vacuum operation is stopped, the wafer 1 is mounted on the partition members on both sides constituting the slot. Placed and contained.

  The above is the configuration of the grinding device 20 and the operation of forming and cleaning the recess 4A on the back surface of the wafer by the grinding device 20. The grinding device 20 includes the cleaning device 70 according to the present invention. According to the cleaning device 70, the wafer 1 is held on the spinner table 71, and the wafer 1 of the spinner table 71 is placed thereon. The upper surface 71 a is a full surface mounting type that is slightly larger than the outer diameter of the wafer 1. For this reason, there is no clue to grip the wafer 1 in the thickness direction, and the exposed surface facing upward is an uneven shape having the concave portion 4A and the annular convex portion 5A. It has been considered difficult.

  However, in the cleaning apparatus 70 of the present embodiment, the annular convex portion 5A can be first picked up and picked up by the wafer pick-up mechanism 90 including the suction pad 94 having the suction portion 94a corresponding to the annular convex portion 5A. Since the annular projecting portion 5A, which is a reinforcing portion, is adsorbed and held without contacting the thinly processed device forming region 4, the wafer 1 can be safely taken up without being damaged. The wafer 1 picked up by the wafer pick-up mechanism 80 is exposed with the surface 1a side to which the protective tape 7 is applied facing downward, and this exposed surface (the surface of the protective tape 7) is the robot of the transfer robot 23. It can be received and held by the pick 23c.

  The wafer 1 is supported on the annular protrusion 5A by the robot pick 23c, and stress is not applied to the thinly processed device forming region 4, so that the wafer 1 is safely transported. Since the wafer 1 is received by the robot pick 23c that sucks and holds the wafer 1 in the state where the wafer 1 is received, the wafer 1 is reliably stored in the narrow slot. Further, at the time of accommodation, the trouble that the robot pick 23c interferes with the partition member of the slot does not occur, and the wafer 1 is accommodated smoothly.

[3] Cleaning Device According to Other Embodiments The cleaning device 70 according to the above embodiment is provided in the grinding device 20, but the present invention includes a mode in which the cleaning device is a single unit. FIG. 10 shows an example of such a cleaning apparatus. Hereinafter, the cleaning apparatus 100 will be described.

  The cleaning apparatus 100 has a rectangular parallelepiped base 101, and a pair of cassette stages 102 is provided on one end side of the base 101. On each cassette stage 102, a cassette 103 similar to the cassettes 22A and 22B is detachably mounted. In the cassette 103, a plurality of wafers 1 are stacked and stored with the back surface 1b side where the recess 4A is formed facing upward. One wafer 1 stored in the cassette 103 is pulled out by the transfer robot (second transfer means) 104 and placed on the positioning table 107 with the back surface 1b facing upward, where a certain position is set. Decided.

  The transfer robot 104 is the same as the transfer robot 23 described above, and an articulated arm 104b is attached to a rotary shaft 104a so as to be horizontally rotatable, and a vacuum suction robot formed in a flat plate shape at the tip of the arm 104b. A pick 104c is attached. One side of the robot pick 104c is a vacuum suction surface, and the suction surface is inserted into the lower surface of the wafer 1 with the suction surface facing upward. The length of the robot pick 104c is sufficiently longer than the diameter of the wafer 1, and therefore the wafer 1 is supported by the robot pick 104c on the annular protrusion 5A. The robot pick 104c can be moved to a desired location by the operation of the rotating shaft 104a and the arm 104b, and is inserted into the cassette 103 to suck the lower surface of the wafer 1 accommodated in the slot and to the positioning table 107. Transfer.

  The transfer robot 104 is supported by the base 101 so as to be movable in the X direction via the moving table 105, and is moved in the X direction by the X direction moving mechanism 106. When the wafer 1 is put in and out of the cassette 103, the transfer robot 104 is appropriately brought close to the cassette 103 by the X-direction moving mechanism 106.

  Next, the wafer 1 is placed concentrically on a disk-shaped spinner table (holding means) 109 by a rotating transfer arm (first transfer means) 108. The transfer arm 108 is the same as the collection arm 27 described above, and the arm 108b is supported on the base 101 via the turning shaft 108a so as to be horizontally turnable, and a vacuum suction type suction pad 108c is attached to the tip of the arm 108b. Is. The outer diameter of the suction pad 108c corresponds to the outer diameter of the wafer 1 or is set to be slightly larger, and an annular suction formed by forming an air suction port on the entire outer periphery of the lower surface of the suction pad 108c. The part is formed. This suction portion has substantially the same diameter and width as the annular convex portion 5 </ b> A formed on the wafer 1. The upper surface of the annular convex portion 5A protruding upward is attracted to the suction portion of the suction pad 108c that is operated in a vacuum, and the wafer 1 is transferred from the positioning table 107 to the spinner table 109 by the turning operation of the arm 108b. .

  The spinner table 109 is the same as the spinner table 71 described above, has a disk shape with an outer diameter slightly larger than the outer diameter of the wafer 1, and is rotated by a drive mechanism (not shown) with the Z direction (vertical direction) as a rotation axis. It is done. On the upper surface (holding surface) 109a of the spinner table 109, the wafer 1 transported by the transport arm 108 is placed concentrically with the back surface 1b side where the recess 4A is formed exposed, and is operated in vacuum. Is absorbed and retained.

  A cleaning water supply mechanism (cleaning means) 110 for cleaning the wafer 1 held on the spinner table 71 is disposed on the back side of the base 71. The cleaning water supply mechanism 110 includes a nozzle stand 111 erected on a base 101 and a nozzle arm that is mounted on the nozzle stand 111 through a nozzle base 112 so as to be horizontally rotatable and has a nozzle 113 at the tip and extends in the horizontal direction. 114. The nozzle arm 114 is located above the spinner table 109 and reciprocates between a retracted position indicated by a broken line in FIG. 10 and a dropping position indicated by a solid line. At the dropping position, the nozzle 113 is positioned at the center of rotation of the spinner table 109. Positioned directly above. A cleaning water supply source (not shown) is provided inside the base 101, and cleaning water such as pure water is supplied from the cleaning water supply source to the nozzle 113 through the nozzle stand 111, the nozzle base 112, and the nozzle arm 114. Pumped.

  The cleaning of the wafer 1 by the cleaning device 100 is the same as that of the cleaning device 70, that is, the cleaning water is rotated from the nozzle 113 of the cleaning water supply mechanism 110 to the recess 4A of the wafer 1 while rotating the wafer 1 by the spinner table 109. After the cleaning, the wafer 1 is dried by blowing dry air from the nozzle 113 onto the back surface 1b of the wafer 1 while increasing the rotation speed of the spinner table 109. An annular cover 115 is provided around the spinner table 109 to prevent the cleaning water from splashing.

  When the cleaning / drying processing of the wafer 1 is completed, the rotation of the spinner table 109 is stopped and the nozzle arm 114 is turned to the retracted position. Next, the vacuum operation of the spinner table 109 is stopped, the wafer 1 is picked up from the spinner table 109 by the transfer arm 108, and then the wafer 1 is sucked and held in a state where the lower surface is supported by the robot pick 104c of the transfer robot 104. Then, it is housed in the slot in the cassette 103 from the positioning table 107. Both of the two cassettes 103 may be used so that the wafers 1 can be taken in and out, and one of the two cassettes 103 may be used separately from the unprocessed side and the other from the processed side.

  Similarly to the cleaning device 70 of the previous embodiment, the cleaning device 100 supports the annular convex portion 5A when transporting the wafer 1 and does not apply stress to the thin device formation region 4. It can be safely transported without being damaged. Further, when the wafer 1 is accommodated in the cassette 103, the wafer 1 can be smoothly accommodated in a narrow slot by the robot pick 104c.

It is the (a) perspective view of the wafer ground back by the grinding device concerning one embodiment of the present invention, and (b) the side view. It is a perspective view which shows the back surface side of the wafer in which the recessed part was formed by grinding. 1 is an overall perspective view of a grinding apparatus according to an embodiment. It is (a) perspective view and (b) side view which show the grinding unit of the grinding apparatus of FIG. It is a top view which shows the attachment structure of a grinding unit. It is a side view which shows the state which has formed the recessed part in the wafer back surface with the grinding unit. It is a perspective view of the washing | cleaning apparatus with which the grinding apparatus of FIG. 3 is provided. It is the (a) side view of a washing | cleaning apparatus, (b) The bottom view of a suction pad. It is a side view which shows the process which picks up a wafer from the spinner table of a washing | cleaning apparatus, and delivers to a conveyance robot in order of (a)-(e). It is a perspective view which shows the washing | cleaning apparatus of other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Semiconductor wafer 1a ... Wafer surface 1b ... Wafer back surface 3 ... Semiconductor chip (device)
DESCRIPTION OF SYMBOLS 4 ... Device formation area 4A ... Concave part 5 ... Periphery surplus area | region 5A ... Annular convex part 20 ... Grinding device 23,104 ... Conveyance robot (2nd conveyance means)
27 ... Recovery arm (transfer means)
30 ... Chuck table (holding means for processing)
40A, 40B ... Grinding unit (grinding means)
70, 100 ... Cleaning device 71, 109 ... Spinner table (holding means)
71a, 109a ... Upper surface (holding surface) of spinner table
80, 110 ... Washing water supply mechanism (cleaning means)
90 ... Wafer pick-up mechanism (first transfer means)
108: Transfer arm (first transfer means)

Claims (2)

The device has a substantially circular device forming region having a plurality of devices formed on the surface, and an outer peripheral surplus region surrounding the device forming region, and a region on the back side corresponding to the device forming region is ground to a predetermined thickness. An apparatus for cleaning the back surface of a wafer in which a recess is formed,
A holding means for holding the wafer in a state where the back surface is exposed on the holding surface, the holding surface having a diameter equivalent to the wafer outer diameter or larger than the wafer outer diameter,
Cleaning means for cleaning the back surface of the wafer held by the holding means;
Holding the outer peripheral surplus area of the wafer whose back surface is cleaned by the cleaning means, and taking up the wafer from the holding means to expose the front side; and
And a second transfer means for adsorbing and holding the vicinity of the outer peripheral surplus area on the front surface side of the wafer held by the first transfer means and transferring the wafer to a predetermined transfer destination. Cleaning device. A wafer having a substantially circular device formation region having a plurality of devices formed on the front surface and an outer peripheral surplus region surrounding the device formation region is ground to a predetermined thickness on the back side region corresponding to the device formation region. A grinding device for forming a recess,
A processing holding means having a holding surface for holding the wafer in a state where the back surface of the wafer is exposed;
A grinding means for grinding the region corresponding to the device formation region of the wafer held on the holding surface to form the concave portion;
A cleaning device for cleaning the back surface of the wafer having the recess formed on the back surface by the grinding means;
A transfer means for holding the outer peripheral surplus area of the wafer having the recess formed on the back surface thereof by the grinding means and transferring it to the cleaning device;
A wafer grinding apparatus, wherein the cleaning apparatus is the cleaning apparatus according to claim 1.

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