JP5381865B2 - Wafer transfer apparatus and wafer transfer method - Google Patents

Description

  The present invention relates to a wafer transfer apparatus and a wafer transfer method.

  Conventional wafer handling methods include a method in which the wafer is vacuum-sucked to the transfer hand (vacuum suction method), a method in which the side of the wafer is sandwiched and held by the transfer hand (mechanical chuck method), and a wafer is attracted to the transfer hand by static electricity. The method (electrostatic chuck method), the method of sucking the wafer to the transfer hand in a pseudo vacuum state by the jet of compressed air (float chuck method), the method of dropping the wafer into the recess of the transfer hand (drop method), etc. It is known.

  First, handling using a vacuum suction method will be described. In handling using the vacuum suction method, a suction pad with suction holes, a suction pad with a porous chuck using a porous (porous) suction plate such as a ceramic, or a vent connected to a vacuum pump is used as a transport hand. A suction pad or the like in which the holes and the suction holes are provided inside the transport hand is used. Also, in handling using the vacuum suction method, the device surface of the wafer should not be scratched or soiled so that the portion of the front surface of the wafer where the element structure is formed (hereinafter referred to as the device surface) will not occur. In general, a surface on which the element structure is not formed (hereinafter referred to as a wafer back surface) on the opposite side is adsorbed by a transfer hand.

  FIG. 21 to FIG. 23 are explanatory views showing the handling using the conventional vacuum suction method. 21 to 23, the element structure of the device surface 2 of the wafer 1 in the plan view of the wafer 1 is not shown (hereinafter, the same applies to FIGS. 1, 5 to 11 and FIGS. 24 to 27). In the handling shown in FIG. 21, a suction pad having a suction hole is used as the transport hand 101. The transfer hand 101 sucks the wafer 1 and a substantially rectangular plate-like body provided with a U-shaped finger portion shorter than the diameter of the wafer 1 as a portion (hereinafter referred to as a suction surface) where the wafer 1 is joined. And a plurality of rubber pads 102. Each rubber pad 102 is provided on the suction surface of the transport hand 101, for example, at an end of the finger portion and a portion connecting the finger portions, and the suction surface of the transport hand 101 is aligned with the back surface (wafer back surface) 3 of the wafer 1. Is located at a portion that overlaps the wafer 1. The rubber pad 102 is connected to a vacuum generation source 104 such as a vacuum pump or an ejector by a pipe 103 such as an air tube for vacuuming. When the rubber pad 102 is evacuated through the pipe 103, the wafer back surface 3 is attracted to the rubber pad 102 and the wafer 1 is held on the transfer hand 101.

  In the handling shown in FIG. 22, a vent hole 113 connected to the vacuum generation source 104 via a pipe 103 is provided inside the transport hand 111. In addition, the transport hand 111 has a plurality of suction holes 112 for sucking the surface of the wafer 1. The position of each suction hole 112 is the same as that of the rubber pad shown in FIG. Each suction hole 112 is connected to a vent hole 113. That is, the suction hole 112 is connected to the vacuum generation source 104 through the pipe 103 connected to the ventilation hole 113. Then, by vacuuming the inside of the transfer hand 111, that is, the inside of the suction hole 112 and the ventilation hole 113, the wafer back surface 3 is sucked into the suction hole 112 and the wafer 1 is held on the transfer hand 111. . Other configurations are the same as the handling using the vacuum suction method shown in FIG.

  In the handling shown in FIG. 23, the transfer hand 121 has a plate-like main body having a substantially rectangular shape longer than the diameter of the wafer 1 and narrower than the diameter of the wafer 1, and a porous shape formed of ceramic, sintered metal, or the like. And a porous chuck 122 which is a plate material. The porous chuck 122 is fitted in the concave portion of the transport hand 121 so that the surface thereof is exposed to the suction surface of the transport hand 121. The porous chuck 122 is connected to the vacuum generation source 104 through the pipe 103. Then, the porous chuck 122 is evacuated through the pipe 103, whereby the wafer back surface 3 is attracted to the porous chuck 122 and the wafer 1 is held on the transfer hand 121.

  Next, handling using the mechanical chuck method will be described. In handling using the mechanical chuck system, a transport hand having a mechanical chuck such as a claw driven by an actuator such as an air cylinder or a motor is used.

  FIG. 24 is an explanatory view showing handling using a conventional mechanical chuck system. In the handling shown in FIG. 24, the transfer hand 131 includes a plate-like main body having a substantially rectangular shape that is longer than the diameter of the wafer 1 and smaller than the diameter of the wafer 1, and a plurality of claws (hereinafter referred to as “claws”) for holding the wafer 1. , Which is a gripping claw) 132. The gripping claws 132 are connected to an actuator 133 such as an air cylinder or a motor embedded in the transport hand 131. By the actuator 133, the gripping claws 132 are driven horizontally with respect to the surface of the wafer 1 to sandwich the side surface of the wafer 1.

  The gripping claws 132 have, for example, a cylindrical shape or a columnar shape having a cross-sectional shape in which the central portion is recessed from the upper side and the lower side. For this reason, when the gripping claws 132 sandwich the side surface of the wafer 1, only the upper and lower end portions 134 of the side surface of the wafer 1 are in contact with the gripping claws 132. Thereby, the positional deviation in the vertical direction with respect to the surface of the wafer 1 is prevented, and it is prevented that the wafer 1 is detached from the gripping claws 132. Further, by determining the cross-sectional shape of the gripping claws 132 so that there is a space between the surface of the wafer 1 and the transport hand 131, the wafer 1 can be gripped while being lifted from the transport hand 131. The wafer 1 can also be gripped with the device surface 2 of the wafer 1 facing the transfer hand 131 side.

  Next, handling using the electrostatic chuck method will be described. In handling using an electrostatic chuck system, a transport hand having an electrostatic chuck mechanism that generates static electricity is used. The electrostatic chuck method is characterized by a high suction holding force. However, since the electrostatic chuck mechanism is heavy and bulky, the thickness of the transport hand itself increases. For this reason, it is not used for transporting the wafer but is often used for holding the wafer fixed.

  FIG. 25 is an explanatory diagram showing handling using a conventional electrostatic chuck system. In the handling shown in FIG. 25, the transfer hand 141 has a plate-like main body having a substantially rectangular shape that is longer than the diameter of the wafer 1 and narrower than the diameter of the wafer 1, and an electrostatic chuck 142 that generates static electricity. ing. The electrostatic chuck 142 is fitted in the recess of the transport hand 141 so that the surface of the electrostatic chuck 142 is exposed to the suction surface of the transport hand 141. Inside the electrostatic chuck 142, a minus electrode 143 and a plus electrode 144 are provided apart from each other. A dielectric 145 that is in contact with the negative electrode 143 and exposed on the surface of the electrostatic chuck 142 is provided. A dielectric 146 that is in contact with the plus electrode 144 and exposed on the surface of the electrostatic chuck 142 is provided. An insulator 147 is filled between the negative electrode 143 and the dielectric 145 and the positive electrode 144 and the dielectric 146 to be electrically insulated. For the same reason as the handling using the vacuum suction method, the wafer back surface 3 is generally sucked to the transfer hand 141.

  In order to attract the wafer back surface 3 to the suction surface of the transport hand 141, first, a high voltage is applied to both the negative electrode 143 and the positive electrode 144. As a result, dielectric polarization occurs in the dielectrics 145 and 146. That is, in the dielectric 145 in contact with the negative electrode 143, the charge distribution is biased toward positive charges on the negative electrode 143 side and negative charges on the wafer 1 side. As a result, inside the wafer 1, the charge distribution is biased toward positive charges on the dielectric 145 side. On the other hand, the charge distribution generated from the plus electrode 144 to the wafer 1 is a charge distribution opposite to the minus electrode 143 side. Due to such a charge distribution, an electrostatic attractive force is generated between the wafer back surface 3 and the electrostatic chuck 142, the wafer 1 and the electrostatic chuck 142 are attracted, and the wafer 1 is held on the transfer hand 141. The

  Next, handling using the float chuck method will be described. In handling using the float chuck system, a transport hand having a float chuck that generates a negative pressure by a jet of compressed air using the Bernoulli principle is used. Since the wafer is maintained in a state of being floated by the negative pressure, the wafer and the transfer hand do not come into contact with each other. However, the wafer side surface or a part of the wafer surface may be brought into contact with the hand so that the wafer does not rotate.

  FIG. 26 is an explanatory diagram showing handling using a conventional float chuck system. In the handling shown in FIG. 26, the transport hand 151 includes a substantially rectangular plate-like body provided with a U-shaped finger portion longer than the diameter of the wafer 1 as the wafer suction surface, and the suction surface of the transport hand 151. And a vent hole 152 for jetting compressed air from the air. The ventilation hole 152 is provided inside the transport hand 151. A plurality of ejection holes 153 for sucking the wafer back surface 3 are provided on the suction surface of the transport hand 151.

  The position of each ejection hole 153 is the same as that of the rubber pad shown in FIG. In addition, each ejection hole 153 is connected to a ventilation hole 152 and is connected inside the transport hand 151. Further, the ejection hole 153 is connected to a compressed air generation source 155 such as a compressor by a pipe 154 such as an air tube connected to the ventilation hole 152.

  The ejection hole 153 has a side wall formed by hollowing out the truncated cone, and the compressed air 161 flowing from the compressed air generation source 155 through the ventilation hole 152 swirls along the side wall of the ejection hole 153. It is structured to be ejected outside. As described above, the compressed air 161 swirls and flows out, so that the negative pressure 160 is generated in the central portion of the ejection hole 153 and a pseudo vacuum state is obtained. Then, the wafer back surface 3 is sucked into the ejection hole 153 so as to be attracted by the negative pressure 160, and the wafer 1 is held in a floating state on the transport hand 151.

  In addition, in the finger portion longer than the diameter of the wafer 1, the horizontal displacement with respect to the wafer back surface 3 is caused in a portion that does not overlap the wafer 1 when the suction surface of the transfer hand 151 is aligned with the wafer back surface 3. A guide pin 156 is provided for prevention. In the cross-sectional view of FIG. 26, the guide pin 156 is not shown.

  Next, handling using the drop method will be described. In handling using the drop-in method, a transfer hand provided with a recess that is just enough to accommodate a wafer is used. In the dropping method, unlike the above-described methods, the wafer is only placed in the concave portion of the transfer hand, so that no external holding force is generated on the wafer.

  FIG. 27 is an explanatory diagram showing handling using a conventional drop method. In the handling shown in FIG. 27, the transfer hand 171 has a plate-like main body having a substantially rectangular shape longer than the diameter of the wafer 1 and narrower than the diameter of the wafer 1, and a recess 172 for accommodating the wafer 1. doing. The recess 172 has a size that allows the wafer 1 to be accommodated. When the wafer 1 is accommodated in the recess 172, the wafer 1 is dropped into the recess 172 so that the wafer back surface 3 side is in contact with the bottom surface of the recess 172. Alternatively, the wafer 1 is picked up by the transfer hand 171 and the wafer 1 is stored in the recess 172. Thereby, it can convey so that the wafer 1 may not fall by the inertial force at the time of conveyance, or centrifugal force.

  As a handling apparatus having such a transport hand, the following apparatus has been proposed. The reticle handling apparatus has a U-shaped hawk at the tip. Adsorption parts are formed on the stepped part provided on the side wall between the arm parts of the U-shaped hawk and on the tip of each arm part. The suction part has an annular protrusion and a recess, and a reticle is placed on the protrusion. The suction part sucks and holds three points (holding points) that are substantially evenly spaced from the outer peripheral edge of the reticle. As a result, the reticle can be stably held and can be safely transported so as not to fall off. The concave portion communicates with the suction hole inside the arm portion. And this adsorption | suction hole is connected with the evacuation passage embed | buried along the length direction of an arm part. The concave part of the suction part of the step part is connected to the vacuum passage through the same suction hole. Each evacuation passage joins at the base to form one passage, and is connected to a vacuum source outside the arm via a valve (for example, see Patent Document 1 below).

  As another device, in a gripping and conveying device for a disk-shaped object composed of at least a wrist block, a conveying hand, a finger, and a claw, the wrist block and the conveying hand are fixed to each other and can be rotated on the wrist block in a horizontal plane. And gripping the peripheral edge of the disk-shaped object by the claw respectively attached to the tips of the two fingers connected to each other and at least one claw fixed to the tip of the transporting hand to transport the disk-shaped object The gripping-type transport device of the present invention, wherein all the claws are in contact with the disk-like object and grip the peripheral edge thereof, and are pressed at the points where they contact the peripheral edges of the claws attached to the tips of the two rotating fingers An apparatus has been proposed in which the direction is substantially the central direction of the disk-like object (for example, see Patent Document 2 below).

  In addition, the following method has been proposed as a method for transporting a wafer. When the semiconductor substrates in the carrier are taken out one by one with a flat transfer hand body and transferred to the processing stage of the next process, a pair of fork portions in the transfer hand body are provided below the semiconductor substrate in the carrier. Are inserted so that there is a gap between the outer peripheral edge of each of the two forks and the inner diameter side of the base portion of both fork portions. Next, the transfer hand body is raised or the carrier is lowered, and the portions near the left and right outer peripheral edges of the semiconductor substrate to be taken out are supported by both fork portions. Note that suction holes each having an upward opening for adsorbing and holding the semiconductor substrate are formed on the upper surfaces of both fork portions (see, for example, Patent Document 3 below).

  Further, in the handling using the above-described vacuum suction method, as shown below, it is determined whether or not the wafer is sucked by the transfer hand (hereinafter referred to as a wafer suction state). FIG. 28 is an explanatory diagram showing determination means for determining a wafer suction state in handling using a conventional vacuum suction method. For example, the case where the wafer 1 is vacuum-sucked to the transfer hand 111 shown in FIG. 22 will be described. As shown in FIG. 28, a switching unit 201 and a filter 202 are connected in series with the vacuum generation source 104 between the vacuum generation source 104 and the ventilation hole 113 in the transport hand 111. The switching unit 201 switches the adsorption of the wafer 1 to the transfer hand 111 and the separation of the wafer 1 from the transfer hand 111. The filter 202 prevents the dust sucked from the suction holes 112 from entering the vacuum generation source 104.

  A pressure sensor 203 is connected between the vacuum generation source 104 and the ventilation hole 113 in parallel with the vacuum generation source 104. The pressure sensor 203 measures the pressure inside the vent hole 113. The pressure value measured by the pressure sensor 203 is displayed on a pressure indicator 204 connected to the pressure sensor 203. The switching unit 201, the filter 202, the pressure sensor 203, and the pressure indicator 204 connected between the vacuum generation source 104 and the ventilation hole 113 are each connected by a pipe 103.

  In the determination means shown in FIG. 28, the presence or absence of vacuum leakage is determined based on the pressure value measured by the pressure sensor 203, and the suction state of the wafer 1 is determined. Specifically, when the pressure measured by the pressure sensor 203 is reduced from the atmospheric pressure to a predetermined value or more and it can be said that the pressure is in a vacuum state, it is determined that there is no vacuum leakage, and the gap between the wafer 1 and the transfer hand 111 is determined. It is determined that the suction force (hereinafter referred to as suction pressure) received by the wafer 1 is strong and the wafer 1 is attracted to the transport hand 111. On the other hand, if the pressure value measured by the pressure sensor 203 does not indicate that the inside of the vent hole 113 is in a vacuum state, it is determined that there is a vacuum leak, the suction pressure to the wafer 1 is low, and the wafer 1 Is determined not to be attracted to the transport hand 111.

  As described above, the following means have been proposed as a determination means for determining the wafer suction state. An air passage is provided in the suction hand, an suction hole is provided on the lower surface of the suction band as an opening of the air passage, and the end of the air passage is connected to an intake port such as a vacuum pump. In addition, a pressure sensor for detecting the intake pressure is installed in a part of the air passage. When the detected pressure of the pressure sensor falls below a certain value, the suction hand sucks the silicon wafer on the lower surface. Detected (for example, see Patent Document 4 below)

JP 2004-071730 A JP 2006-150538 A JP 2006-190817 A JP 02-116142 A

  However, in each handling mentioned above (refer to Drawing 21-Drawing 25 and Drawing 27), the element structure of wafer back 3 will contact a conveyance hand. For this reason, when an element structure such as a diffusion layer is formed on the wafer back surface 3, for example, the element structure on the wafer back surface 3 is scratched, rubbed, soiled, stained, or the like (hereinafter referred to as an adsorption mark). .

  Further, in handling using the mechanical chuck system (see FIG. 24), there is a possibility that chipping (chipping) may occur in the upper and lower end portions 134 of the side surface of the wafer 1 in contact with the gripping claws 132. Further, in handling using the float chuck method (see FIG. 26), if the guide pins 156 that prevent positional deviation and the side surface of the wafer 1 are in contact with each other, the side surface of the wafer 1 may be lost.

  In addition, thinning of the wafer is currently promoted in order to improve the performance of the device chip. For example, the thickness of the peripheral portion along the outer periphery on the back side of the wafer is left as a reinforcing portion (rib portion), A wafer having a stepped shape on the back side of the wafer (hereinafter referred to as a rib wafer) has been proposed. Since the strength of the rib wafer is maintained by leaving the rib portion, cracks and warpage are reduced. However, it is difficult to handle such a rib wafer (see FIGS. 21 to 27) in the same manner as the flat wafer (wafer without a rib portion) as described above, and the following problems occur.

  FIG. 19 is a plan view showing the structure of the rib wafer. In FIG. 19, the planar shape of the front surface and the back surface of the rib wafer is shown on the upper side and the lower side of the drawing, and a sectional view taken along the cutting line A-A ′ of the rib wafer is shown in the center of the drawing. As shown in FIG. 19, for example, the rib wafer 10 has an entire periphery or a part of the outer peripheral end portion on the back surface 3 side of a portion (region other than the device surface 2) 11 where the element structure on the front surface of the wafer is not formed. Only the central part of the wafer is thinned, leaving the ribs 12. For example, a diffusion layer is formed as an element structure in a central portion (hereinafter, referred to as a rear surface central portion) 13 which is a bottom surface of the concave portion of the rear surface 3 of the rib wafer 10. That is, the back surface 3 of the rib wafer 10 includes a back surface central portion 13 in which the element structure is formed and a back surface (hereinafter referred to as a rib back surface) 14 of the rib portion 12 in which the element structure is not formed.

  When the rib wafer 10 is handled using the vacuum suction method or the electrostatic chuck method (see FIGS. 21 to 23 and 25), the device surface 2 is aligned with the device surface 2 of the rib wafer 10 facing the transfer hand side. Will come into contact with the suction surface of the transport hand. For this reason, suction marks are generated on the device surface 2 of the rib wafer 10.

  On the other hand, when the back surface central portion 13 of the rib wafer 10 is aligned toward the transport hand side, the rib back surface 14 in contact with the transport hand is displaced from the suction hole due to variations in processing accuracy of the rib portion 12, and the suction hole is completely blocked. May not be possible. For this reason, a vacuum leak occurs, and there is a possibility that the rib wafer 10 is not attracted to the transport hand. This increases the possibility of dropping the rib wafer 10 when the rib wafer is transported.

  Further, in the conventional determination means (see FIG. 28) for determining the flat wafer adsorption state described above, when a vacuum leak occurs, a similar value is displayed on the pressure display regardless of the degree of the leak. Therefore, even if it is attempted to determine the suction state of the rib wafer 10 by the conventional determination means, there is a vacuum leak but there is a sufficient suction force (when the rib back surface 14 is slightly displaced from the suction hole), and the suction due to the vacuum leak. It cannot be distinguished from the case where the force is not sufficient (when the displacement is large and the suction hole is almost fully open). That is, it is difficult to determine the suction state of the rib wafer 10. For this reason, the possibility of dropping the rib wafer 10 during the conveyance of the rib wafer 10 cannot be reduced.

  Further, when the mechanical chuck method is used (see FIG. 24), the upper and lower end portions 134 of the side surface of the rib portion in contact with the gripping claws 132 may be chipped as in the case of a flat wafer. In addition, the chip | tip of the wafer nail | claw can be reduced by making the material of the nail | claw 132 for a grip into elastic materials, such as rubber | gum. However, in this case, dust and dirt are generated in a clean room for manufacturing a semiconductor element. Therefore, it is not appropriate to use the gripping claws 132 made of an elastic material.

  FIG. 20 is a cross-sectional view showing handling of a rib wafer using a float chuck method. When the float chuck method is used (see FIG. 26), as shown in FIG. 20, when the back surface 3 of the rib wafer 10 is directed toward the transfer hand 151, only the back central portion 13 of the rib wafer 10 is ejected by the negative pressure 160. Since it is sucked into the holes 153, the rib wafer 10 is deformed. As a result, stress concentrates in the vicinity of the boundary 191 between the back surface central portion 13 and the rib portion 12, and there is a possibility that the wafer is cracked. In addition, there is a concern that the rib back surface 14 comes into contact with the transport hand 151 and, for example, an end portion 192 of the rib back surface 14 is chipped, causing generation of particles.

  In handling using the dropping method (see FIG. 27), the rib wafer 10 is merely placed on the transport hand 171 and is not securely held. For this reason, when the transfer hand 171 is inclined from the horizontal state on which the rib wafer 10 is placed, the rib wafer 10 may fall. Therefore, for example, when the rib wafer 10 is automatically transported, it is difficult to reliably transport the rib wafer 10 without dropping it.

  In order to eliminate the above-described problems caused by the prior art, the present invention provides a wafer transfer apparatus and wafer transfer method for transferring a wafer without causing suction marks or damage on the surface on which the device of the wafer is formed or on the surface on which the device is formed. The purpose is to provide.

In order to solve the above-described problems and achieve the object of the present invention, a wafer transfer apparatus according to the present invention includes a transfer means having a plurality of suction holes for sucking a wafer, and is provided inside the transfer means. A ventilation hole connected to the hole, and a vacuum generating means connected to the ventilation hole for evacuating the inside of the ventilation hole. A support part that supports the wafer in contact with a region where the wafer is not formed is provided, and the support part is a part of the transport unit that faces the wafer and is closer to the wafer than a part that does not contact the wafer. A wafer that protrudes, the suction holes are provided in the support portion, a plurality of ventilation holes are provided apart from each other, and each of the ventilation holes is connected to at least one of the suction holes. Carrier machine Characterized in that it comprises a.

In the wafer transfer apparatus according to the present invention as set forth in the invention described above , the vent holes are connected to different suction holes.

Further, in the wafer transfer apparatus according to the present invention, in the above invention, the support portion is provided at a position overlapping with a peripheral portion along the outer periphery of the wafer when the transfer means is aligned with the wafer. It is characterized by.

Further, in the wafer transfer apparatus according to the present invention, in the above invention, the support portion is provided at a position overlapping with a peripheral portion left thick along the outer periphery of the wafer when the transfer means is aligned with the wafer. It is characterized by being.

Further, in the wafer transfer apparatus according to the present invention, in the above invention, when the suction hole is aligned with the transfer means on the surface side forming a step shape by the peripheral portion left thick along the outer periphery of the wafer, It is provided at a position overlapping with the peripheral portion.

Moreover, the wafer transfer apparatus according to the present invention is characterized in that, in the above invention, the wafer transfer mechanism further comprises a reversing unit that reverses the surface of the wafer attracted to the transfer unit by turning over the transfer unit. To do.

In the wafer transfer apparatus according to the present invention as set forth in the invention described above , the wafer transfer mechanism measures the flow velocity of air flowing through the ventilation hole of the transfer means that is evacuated by the vacuum generating means. And a suction determination unit for determining whether or not a wafer is sucked to the transfer unit based on the flow rate measured by the flow rate measuring unit.

Further, a wafer transfer apparatus according to the present invention is a wafer transfer mechanism according to the above invention, a wafer storage means for storing a wafer to be taken in and out by the wafer transfer mechanism, and a wafer transfer means that is taken out from the wafer storage means by the wafer transfer mechanism. And wafer alignment means for aligning the position of the wafer.

Further, in order to solve the above-described problems and achieve the object of the present invention, a wafer transfer method according to the present invention is such that a portion where the element structure of the wafer is not formed contacts the support portion of the transfer means, and The wafer is transported in a state in which a portion where the structure is not formed is adsorbed by a plurality of adsorption holes provided in the support portion and capable of being evacuated independently of each other.

In the wafer transfer method according to the present invention, in the above invention, when the wafer is sucked into the suction hole, the flow velocity of the air flowing by evacuating the suction hole is measured, and the wafer suction is performed based on the measurement result. It is characterized by determining the degree of.

Further, the wafer transfer method according to the present invention as set forth above, the wafer peripheral portion is left thicker along the periphery, to adsorb the surface of the peripheral portion of the side forming the stepped shape by the peripheral portion It is characterized by.

The wafer transfer method according to the present invention is characterized in that, in the above invention, all the suction holes are evacuated independently of each other.

  According to the above-described invention, the support means is provided at the position where the transfer means overlaps with the peripheral portion along the outer periphery of the wafer, that is, the position where the element structure is not formed, when the transfer means is aligned with the wafer. It has been. In addition, the suction hole is provided in the support portion. For this reason, the transfer means sucks a portion where the element structure of the wafer is not formed. Thus, the suction holes do not contact the device surface provided on the front surface of the wafer and the diffusion layer provided on the back surface side of the wafer. Moreover, the device surface of the wafer does not come into contact with the transfer hand by the support unit. In addition, since the vacuum systems for the plurality of suction holes are provided independently from each other, even if a vacuum leak occurs in one suction hole when the transport means is sucked to the wafer, there is a gap between the wafer and the wafer. The wafer can be sucked by other suction holes that are not generated. Thereby, possibility that a wafer will fall can be reduced. Further, since the wafer can be reliably adsorbed to the transfer means, it is possible to reduce the falling of the wafer even if the wafer is transferred so as to reverse the direction of the front surface and the back surface of the wafer. .

Further, according to the above-described invention , the presence or absence of vacuum leakage is determined based on the flow velocity of the air flowing through the ventilation hole of the transfer means, and the wafer adsorption state is determined. For this reason, the suction hole is not partially blocked by a peripheral portion (for example, a rib portion) along the outer periphery of the wafer, and a gap is formed, but there is a suction force, and the suction hole is along the outer periphery of the wafer. Since it is not blocked at all by the peripheral portion, it can be determined that the suction force is insufficient . Thus, it is possible to determine the case where the wafer is reliably attracted to the transfer means and transfer the wafer.

Further, according to the above-described invention , the wafer can be easily transferred and reversed while the wafer is attracted to the transfer means. Thereby, it is possible to avoid the wafer from being damaged by human error.

  According to the wafer transfer apparatus and the wafer transfer method of the present invention, there is an effect that the wafer can be transferred without causing suction marks or damage on the surface on which the device of the wafer is formed or the surface on which the device is formed.

It is explanatory drawing shown about the handling concerning Embodiment 1. FIG. It is explanatory drawing shown about another example of the handling concerning Embodiment 1. FIG. It is explanatory drawing shown about another example of the handling concerning Embodiment 1. FIG. It is explanatory drawing shown about another example of the handling concerning Embodiment 1. FIG. It is explanatory drawing shown about the handling concerning Embodiment 2. FIG. It is sectional drawing which shows an example of the adsorption position of the rib part to a conveyance hand. It is sectional drawing which shows an example of the adsorption position of the rib part to a conveyance hand. It is sectional drawing which shows an example of the adsorption position of the rib part to a conveyance hand. It is explanatory drawing shown about another example of the handling concerning Embodiment 2. FIG. It is explanatory drawing shown about the handling concerning Embodiment 3. FIG. It is explanatory drawing shown about the handling concerning Embodiment 4. FIG. FIG. 10 is an explanatory diagram illustrating determination means for determining a wafer suction state according to a fifth embodiment; It is sectional drawing which shows an example of the adsorption position of the rib part to a conveyance hand. FIG. 10 is an explanatory diagram illustrating a wafer transfer mechanism unit according to a sixth embodiment; FIG. 10 is a plan view showing a wafer transfer apparatus according to a seventh embodiment. FIG. 10 is a cross-sectional view illustrating a wafer transfer device according to a seventh embodiment. It is a characteristic view showing the relationship between the flow velocity flowing inside the transfer hand and the suction state of the wafer. FIG. 10 is a characteristic diagram illustrating a relationship between the pressure inside the transfer hand and the wafer suction state. It is a top view shown about the structure of a rib wafer. It is sectional drawing shown about the handling of the rib wafer using a float chuck system. It is explanatory drawing shown about the handling using the conventional vacuum suction system. It is explanatory drawing shown about the handling using the conventional vacuum suction system. It is explanatory drawing shown about the handling using the conventional vacuum suction system. It is explanatory drawing shown about the handling using the conventional mechanical chuck system. It is explanatory drawing shown about the handling using the conventional electrostatic chuck system. It is explanatory drawing shown about the handling using the conventional float chuck system. It is explanatory drawing shown about the handling using the conventional dropping method. It is explanatory drawing which shows the determination means which determines the adsorption | suction state of the wafer in the handling using the conventional vacuum adsorption system.

  Exemplary embodiments of a wafer transfer apparatus and a wafer transfer method according to the present invention will be explained below in detail with reference to the accompanying drawings. Note that, in the following description of the embodiments and the accompanying drawings, the same reference numerals are given to the same components, and duplicate descriptions are omitted.

(Embodiment 1)
FIG. 1 is an explanatory diagram of handling according to the first embodiment. Here, the entire periphery or a part of the outer peripheral end portion on the back surface 3 side of the wafer is left as the reinforcing portion (rib portion) 12, the center portion (back surface center portion) 13 of the back surface 3 is thinned, and the back surface 3 side is stepped. A description will be given using a shaped wafer (rib wafer) 10 (see FIG. 19). In the handling shown in FIG. 1, the transport hand (transport means) 20 has a plate-shaped main body and suction holes 22 for sucking the rib wafer 10. The length of the plate-shaped main body in the insertion direction into the wafer cassette (not shown) is preferably longer than the diameter of the rib wafer 10. This is because a plurality of suction holes 22 can be provided at intended locations, which will be described later.

  The length (width) of the plate-like main body in the direction orthogonal to the direction of insertion into the wafer cassette is preferably smaller than the diameter of the rib wafer 10. This is to prevent the transport hand 20 from coming into contact with the wafer cassette when the transport hand 20 is inserted into a wafer cassette (not shown). When the portion supporting the wafer from the side wall of the wafer cassette protrudes inward, it is preferable that the transfer hand 20 has a size that does not contact the portion supporting the wafer on the side wall of the wafer cassette. A first vent hole 21 and a second vent hole 23 are provided inside the main body of the transport hand 20. Further, the main body of the transport hand 20 has a shape in which the width a of the portion (suction surface) where the rib wafer 10 is combined is wider than the width b of the portion where the rib wafer 10 is not aligned.

  On the suction surface of the transport hand 20, there is provided a stepped portion 24 (support portion) that supports the rib wafer 10 in contact with a portion (region other than the device surface 2) 11 where the element structure of the rib wafer 10 is not formed. The step portion 24 protrudes closer to the rib wafer 10 than the portion of the transport hand 20 that faces the portion (device surface) 2 where the element structure of the front surface of the rib wafer 10 is provided. For this reason, a portion of the transfer hand 20 that faces the portion 2 provided with the element structure of the front surface of the rib wafer 10 is a portion that does not contact the rib wafer 10.

  That is, the stepped portion 24 overlaps the portion 11 where the element structure of the front surface of the rib wafer 10 is not formed when the transfer hand 20 is aligned with the rib wafer 10, and the element structure of the front surface of the rib wafer 10 is provided. It does not overlap with the part (device surface) 2. For example, in the rib wafer 10, the portion 11 where the element structure on the front surface is not formed is a rib portion 12. That is, the step portion 24 is provided at a position overlapping the rib portion 12 of the rib wafer 10.

  In addition, the surface which contacts the rib wafer 10 of the level | step-difference part 24 is processed so that the rib wafer 10 may not be damaged. The contact surface of the stepped portion 24 with the rib wafer 10 may be polished, for example. As shown in FIG. 1, if the protrusion-shaped step portion 24 is provided and the rib wafer 10 is sucked by the step portion 24, the area to be polished is small.

  Although not shown, a low dusting resin (for example, polyetheretherketone) may be attached to the contact surface (surface) of the stepped portion 24 with the rib wafer 10. By doing so, the surface of the rib wafer 10 is not damaged regardless of which surface of the rib wafer 10 is attracted to the stepped portion 24. Moreover, since the adhesion degree of both improves, air leakage can be reduced.

  The step portion 24 is provided with an adsorption hole 22. A plurality of first ventilation holes 21 are provided. Each first ventilation hole 21 is connected to at least one suction hole 22. Further, it is desirable that the suction hole 22 is provided at a position where the rib wafer 10 can be sucked to the transport hand 20 in a balanced manner. Further, the suction holes 22 are preferably provided so that the suction area is as large as possible.

  For example, the suction hole 22 has an arc shape along the outer periphery of the rib wafer 10. Specifically, as shown in FIG. 1, the suction holes 22 are at a position where the peripheral portion along the outer periphery of the rib wafer 10 can be sucked, and at a plurality of locations facing each other across the center position of the rib wafer 10. Is provided. At this time, the stepped portion 24 only needs to be provided at a position where at least the suction hole 22 is provided on the entire periphery of the peripheral portion along the outer periphery of the rib wafer 10.

  Each suction hole 22 is connected by a first ventilation hole 21 provided inside the transport hand 20, and is connected inside the transport hand 20. For example, as shown in FIG. 1, the first ventilation hole 21 connects the ends of the opposing suction holes 22 having an arc shape. That is, in FIG. 1, the planar shape formed by the suction hole 22 and the first ventilation hole 21 is, for example, a substantially oval shape. As described above, all the suction holes 22 and the first ventilation holes 21 are connected together.

  Further, a second ventilation hole 23 is connected to the first ventilation hole 21 via an adsorption hole 22. The second ventilation hole 23 is provided inside the transport hand 20. Further, the second ventilation hole 23 is connected to a vacuum generation source (vacuum generation means) 26 via a pipe 25 for evacuation connected to the outside of the transport hand 20. In other words, a continuous hole (vacuum system) formed by the first ventilation hole 21 and the second ventilation hole 23 that connects the suction hole 22 and the pipe 25 is provided inside the transport hand 20. Since the transport hand 20 is often used in, for example, a clean room, the pipe 25 is desirably formed of a material that does not generate dust.

  The vacuum generation source 26 evacuates the inside of the transport hand 20, that is, the inside of the suction hole 22, the first ventilation hole 21, and the second ventilation hole 23. By evacuating the inside of the transport hand 20, the rib wafer 10 is sucked into the suction holes 22 and held on the transport hand 20. The pipe 25 may be an air tube or the like. The vacuum generation source 26 may be a vacuum pump or an ejector.

  A guide pin 27 is provided at an end portion of the transport hand 20 at a position just in contact with the side surface of the rib wafer 10 when the transport hand 20 is aligned with the rib wafer 10. The guide pins 27 serve as a reference when aligning the position at which the rib wafer 10 is attracted to the transport hand 20. That is, the guide pin 27 is provided at a position where the wafer is disposed at a predetermined position on the transport hand 20 when the side surface is in contact with the side surface of the wafer. For example, the guide pin 27 is provided so that the center position of the arcuate suction hole 22 facing the center position of the rib wafer 10 coincides with the side surface of the rib wafer 10.

  The guide pin 27 is provided at the front end of the transport hand 20. That is, the guide pin 27 is provided at the front end of the transfer hand 20 in the insertion direction when the transfer hand 20 is inserted into the wafer cassette. Further, the guide pins 27 protrude upward from the stepped portion 24 that is a portion with which the rib wafer 10 contacts. For example, the guide pin 27 is provided on the step portion 24 provided at the tip of the transport hand 20. By providing the guide pins 27 in this manner, the side surfaces of the guide pins 27 are in contact with the side surfaces of the rib wafer 10 when the transport hand 20 is pulled out from the wafer cassette. Thereby, the wafer can be adjusted to a predetermined position on the transfer hand 20.

  Specifically, the transport hand 20 operates as follows. For example, a case will be described in which the transfer hand 20 immediately before being inserted into the wafer cassette is positioned at substantially the same height as a rib wafer (here, simply referred to as a wafer) in the wafer cassette. The same height as the wafer means the height at which the wafer is placed on the stepped portion 24 of the transfer hand 20 when the transfer hand 20 is translated under the wafer. Further, the suction surface of the transport hand 20 faces upward.

  First, the transfer hand 20 is lowered until it is positioned below the wafer. At this time, when the transfer hand 20 is inserted into the wafer cassette, the transfer hand 20 is moved in the vertical direction until the upper end of the guide pin 27 reaches a height that does not hit the wafer. Next, the transfer hand 20 is inserted into the wafer cassette, and the transfer hand 20 is moved in the horizontal direction until the transfer hand 20 is located directly below the wafer. At this time, the transfer hand 20 is inserted into the back of the wafer cassette until the upper end of the guide pin 27 does not face the wafer surface.

  Next, the transfer hand 20 is raised until the stepped portion 24 of the transfer hand 20 contacts the wafer. As a result, the transfer hand 20 moves to a position where the side surface of the guide pin 27 and the side surface of the wafer face each other. As described above, since the transfer hand 20 moves in the horizontal direction to a position where the upper end of the guide pin 27 does not face the surface of the wafer, the guide pin 27 is not yet in contact with the wafer at this time.

  Next, the transfer hand 20 is pulled out from the insertion slot of the wafer cassette. At this time, the side surface of the guide pin 27 is in contact with the side surface of the wafer. As described above, the guide pin 27 is a reference for performing alignment for attracting the wafer. For this reason, the wafer is aligned by pulling out the transfer hand 20 from the wafer cassette. The process of attracting the wafer to the transfer hand 20 may be performed immediately after the wafer alignment or after the transfer hand 20 is moved to the outside of the wafer cassette. Thereby, a wafer is taken out from the wafer cassette.

  The movement path of the transfer hand 20 described above is an example, and various changes can be made according to the manufacturing process of the semiconductor device. At this time, the wafer cassette may have one entrance / exit for the transport hand 20 to enter / exit, or may have a plurality of entrances / exits according to the movement path of the transport hand 20.

  Further, the wafer may be taken out from the wafer cassette with the suction surface of the transport hand 20 facing downward. In this case, the vertical movement direction of the transport hand 20 is opposite to the above-described case where the suction surface of the transport hand 20 (the surface on which the step portion 24 is provided) is directed upward. That is, the transfer hand 20 moves above the wafer before being inserted into the wafer cassette. Then, the transfer hand 20 moves downward in the wafer cassette and contacts the wafer.

  FIG. 2 is an explanatory diagram of another example of handling according to the first embodiment. The wafer may be aligned by bringing the side surface of the guide pin 27 into contact with the side surface of the wafer cassette (not shown) on the insertion port side. In the transport hand 220 shown in FIG. 2, the guide pin 27 is provided inside the transport hand 220 from the tip of the transport hand 220. For example, the guide pin 27 is provided on the step portion 24 provided inside the transport hand 220. The distance from the front end of the transfer hand 220 to the guide pins 27 is preferably equal to or greater than the diameter of the wafer. By providing the guide pins 27 in this manner, the side surfaces of the guide pins 27 are in contact with the side surfaces of the rib wafer 10 when the transfer hand 220 is inserted into the wafer cassette. Thereby, the wafer can be adjusted to a predetermined position on the transfer hand 220.

  Further, the transport hand 220 moves on an extension line in the insertion direction of the transport hand 220. That is, after the transfer hand 220 is inserted into the wafer cassette, the transfer hand 220 is pulled out of the wafer cassette while maintaining the height and the traveling direction at the time of insertion. For this reason, when the transfer hand 220 is used, the wafer cassette preferably has a shape having an outlet through which the transfer hand 220 can be removed at a position different from the insertion port into which the transfer hand 220 is inserted. For example, the wafer cassette has a cylindrical shape with the back side facing the insertion port of the transfer hand 220 opened as an outlet. Other configurations are the same as those of the transport hand 20 shown in FIG.

  Specifically, the transport hand 220 operates as follows. First, the transfer hand 220 is inserted into the wafer cassette. At this time, the side surface of the guide pin 27 is in contact with the side surface of the wafer cassette on the insertion port side, and the wafer is aligned. Then, the transport hand 220 is moved in the horizontal direction while maintaining the height and the traveling direction when the transport hand 220 is inserted into the wafer cassette. As a result, the transfer hand 220 is pulled out of the wafer cassette and the wafer is taken out.

  Thus, by using the transfer hand 220, before the transfer hand 220 moves directly below the wafer, the operation of the transfer hand 220 performed to avoid contact between the guide pins 27 and the wafer becomes unnecessary. That is, it is not necessary to move the transport hand 220 in the vertical direction. Therefore, the wafer can be taken out from the wafer cassette only by moving the transfer hand 220 in the horizontal direction and passing through the wafer cassette.

  FIG. 3 is an explanatory diagram of another example of handling according to the first embodiment. It is good also as a structure which provided the level | step-difference part on the conveyance hand by making the shape which dented the part facing the device surface 2 of the rib wafer 10 among conveyance hands. In the transport hand 230 shown in FIG. 3, a step 24 is provided at the front end of the transport hand 230. Further, in the transport hand 230, the portion where the step portion 24 on the front end side is provided and the portion not facing the rib wafer 10 on the rear end side (hereinafter referred to as a root portion) have the same thickness. That is, a recess is formed by the step portion 24 and the base portion. The base portion of the transfer hand 230 extends to a region below the rib portion 12 of the rib wafer 10 and contacts the rib portion 12. Thereby, the base part of the conveyance hand 230 functions as a step part. Other configurations are the same as those of the transport hand 20 shown in FIG.

  FIG. 4 is an explanatory diagram of another example of handling according to the first embodiment. You may make the conveyance hand 20 adsorb | suck the back surface 3 side of the rib wafer 10. FIG. In the handling shown in FIG. 4, the back surface (rib back surface) 14 of the rib portion 12 of the rib wafer 10 is attracted to the transport hand 20. The step portion 24 is provided at a position overlapping the rib back surface 14 of the rib wafer 10. At this time, the suction hole 22 is preferably provided at a position where the suction hole 22 is completely closed by the rib back surface 14. Other configurations are the same as those of the transport hand 20 shown in FIG.

  As described above, according to the first embodiment, the transport hand 20 has a portion (device surface) in which the element structure of the front surface of the rib wafer 10 is not formed when the transport hand 20 is aligned with the rib wafer 10. A stepped portion 24 is provided at a position overlapping the region 11 other than 2). Further, the suction hole 22 is provided in the step portion 24. For this reason, the transport hand 20 sucks the portion 11 or the rib back surface 14 where the element structure of the front surface of the rib wafer 10 is not formed. Thereby, the suction hole 22 does not contact the diffusion layer provided on the device surface 2 of the rib wafer 10 and the back surface 3 side of the rib wafer 10. Therefore, the rib wafer 10 can be transported without causing scratches, rubbing, dirt, stains, or the like due to contact with the suction holes 22. Further, when the device surface 2 side of the rib wafer 10 is attracted to the transport hand 20, the device surface 2 of the rib wafer 10 is not in contact with the transport hand 20 due to the step portion 24. For this reason, the rib wafer 10 can be transported without causing suction marks on the device surface 2 of the rib wafer 10. Further, the transport hand 20 sucks only the rib portion 12 left thick at the peripheral portion of the rib wafer 10. For this reason, even if the suction force (suction pressure) received by the rib wafer 10 is strong, the rib wafer 10 can be prevented from being deformed. Thereby, it is possible to prevent the rib wafer 10 from being damaged such as chipping or cracking.

(Embodiment 2)
FIG. 5 is an explanatory diagram of handling according to the second embodiment. A plurality of first ventilation holes independent from each other may be provided inside the transport hand, and the plurality of suction holes independent from each other may be evacuated separately.

  In the second embodiment, as shown in FIG. 5, there are a portion where the end portions of the suction holes 32 are connected by the first ventilation hole 31 and a portion where the end portions are not connected. That is, the first ventilation holes 31 are not connected to each other and are independent from each other.

  A different second ventilation hole 33 is connected to each first ventilation hole 31 via an adsorption hole 32. Each second ventilation hole 33 is connected to the vacuum generation source 26 via a separate pipe 25. That is, each suction hole 32 is connected to a different pipe 25 by a plurality of vacuum systems which are formed by the first ventilation hole 31 and the second ventilation hole 33 and are independent from each other. Other configurations are the same as those in the first embodiment.

  6 to 8 are cross-sectional views illustrating an example of a position where the rib portion is attracted to the transport hand. 6 to 8, the rib back surface 14 is adsorbed to the step portion 24 of the transport hand 30 shown in FIG. The device surface of the rib wafer 10 is not shown. In FIG. 6, the rib wafer 10 is held in a state where the suction holes 32 are completely closed by the rib back surface 14. 7 and 8, the rib wafer 10 is held in a state where the suction holes 32 are not partially blocked by the rib back surface 14 and a gap 42 is generated. The gap 42 is generated when, for example, the position where the stepped portion 24 and the rib portion 12 are aligned is shifted due to variations in the processing accuracy of the rib portion 12.

  The conveyance hand 30 shown in FIG. 5 is not limited to the state where there is no gap as shown in FIG. 6, but also holds the rib wafer 10 while holding the gap 42 as shown in FIGS. 7 and 8. Can do. The reason is as follows. As described above, each suction hole 32 is provided with a vacuum system (first ventilation hole 31 and second ventilation hole 33) that can independently maintain a vacuum state. For this reason, even if a vacuum leak occurs in one suction hole 32, the vacuum state can be maintained in another suction hole 32 in which no gap is formed between the rib wafer 10.

  FIG. 9 is an explanatory diagram of another example of handling according to the second embodiment. The rib wafer 10 having the notch 15 may be adsorbed to the transfer hand 30 shown in FIG. As shown in FIG. 9, even if the notch 15 overlaps the suction hole 32 and a gap 42 is generated between the rib wafer 10 and the suction hole 32, the transfer hand 30 can suck and hold the rib wafer 10. . The reason is the same as the case where a gap as shown in FIGS. 7 and 8 is generated.

  Further, a rib wafer having an orientation flat may be adsorbed on the transport hand shown in FIG. Even if the orientation flat overlaps the suction hole and a gap is generated between the rib wafer and the suction hole, the transport hand can suck and hold the rib wafer. The reason is the same as that of the rib wafer having the notch described above.

  As described above, according to the second embodiment, the same effect as in the first embodiment can be obtained. In addition, since the vacuum systems for the plurality of suction holes 32 are provided independently of each other, even if a vacuum leak occurs in one suction hole 32, other suction holes in which no gap is generated between the rib wafer 10. At 32, the rib wafer 10 can be adsorbed. Thereby, the rib wafer 10 can be transported without dropping. Moreover, since the rib wafer 10 can be reliably adsorbed to the transport hand 30, even if the rib wafer 10 is transported so that the direction of the front surface and the back surface of the rib wafer 10 is reversed, the rib wafer 10 falls. Can be reduced. Therefore, the rib wafer 10 can be transported without being damaged.

(Embodiment 3)
FIG. 10 is an explanatory diagram of handling according to the third embodiment. In the second embodiment, the second ventilation hole may be directly connected to the first ventilation hole.

  In the third embodiment, as shown in FIG. 10, the second ventilation hole 53 is directly connected to the first ventilation hole 51 without passing through the suction hole 52 inside the conveyance hand 50. Other configurations are the same as those in the second embodiment.

  As described above, according to the third embodiment, the same effect as in the first and second embodiments can be obtained.

(Embodiment 4)
FIG. 11 is an explanatory diagram of handling according to the fourth embodiment. You may provide the vacuum system which connects an adsorption hole and piping for every adsorption hole.

  In the fourth embodiment, as shown in FIG. 11, different second vent holes 63 are connected to the respective suction holes 62. Further, the suction holes 62 are not connected to each other. That is, the first ventilation hole for connecting the suction holes 62 to each other is not provided. Further, different pipes 25 are connected to the respective second ventilation holes 63. Other configurations are the same as those in the second embodiment.

  As described above, according to the fourth embodiment, the same effect as in the first and second embodiments can be obtained.

(Embodiment 5)
FIG. 12 is an explanatory diagram of a determination unit that determines the wafer suction state according to the fifth embodiment. The conveyance hand shown in Embodiments 2 to 4 may be provided with a determination unit that determines whether or not the rib wafer 10 is adsorbed to the conveyance hand (the adsorption state of the rib wafer). Here, description will be made using the transport hand (see FIG. 5) described in the second embodiment.

  In the fifth embodiment, as shown in FIG. 12, a switching unit 71 and a filter 72 are connected in series with the vacuum generation source 26 between the vacuum generation source 26 and the second ventilation hole 33. The switching unit 71 switches the adsorption and desorption of the rib wafer 10 to and from the transfer hand 30. The filter 72 prevents dust sucked from the suction holes 32 from entering the vacuum generation source 26.

  A flow rate sensor 73 is connected in parallel with the vacuum generation source 26 between the vacuum generation source 26 and the second ventilation hole 33. The flow velocity sensor 73 is provided for each of a plurality of vacuum systems provided independently inside the transport hand 30. That is, the flow rate sensor 73 is provided for each of the plurality of pipes 25. The flow velocity sensor 73 measures the flow velocity of the air flowing inside the transport hand 30 (first ventilation hole 31 and second ventilation hole 32) that is evacuated by the vacuum generation source 26 (flow velocity measurement means). . Further, the flow rate sensor 73 determines whether or not the rib wafer 10 is attracted to the transport hand 30 based on the measured flow rate (suction determination unit). The flow rate measured by the flow rate sensor 73 is displayed on a flow rate display 74 connected to the flow rate sensor 73. The switching unit 71, the filter 72, the flow rate sensor 73, and the flow rate indicator 74 connected between the vacuum generation source 26 and the second ventilation hole 33 are each connected by a pipe 25.

  FIG. 13 is a cross-sectional view illustrating an example of a position where the rib portion is attracted to the transport hand. In the determination means shown in FIG. 12, the presence or absence of a vacuum leak is determined based on the flow rate measured by the flow rate sensor 73, and it is determined whether or not the rib wafer 10 is attracted to the transfer hand 30 (the attracted state of the rib wafer). For example, the suction hole 32 is completely blocked by the rib back surface 14 and there is no gap (see FIG. 6), or the suction hole 32 is not partially blocked by the rib back surface 14 and a gap is generated (FIG. 7). , 8), as shown in FIG. 13, it is determined whether the suction holes 32 are not blocked by the rib back surface 14 at all.

  Specifically, when the flow rate measured by the flow rate sensor 73 is equal to or less than a preset threshold value, it is determined that there is no vacuum leak, and the suction force (suction force) received by the wafer 1 between the rib wafer 10 and the transfer hand 30 is determined. The pressure is strong, and it is determined that the rib wafer 10 is attracted to the transport hand 30. On the other hand, when the flow velocity sensor 73 determines that the flow velocity is greater than a preset threshold value, it is determined that there is a vacuum leak, the adsorption pressure to the rib wafer 10 is weak, and it is determined that the rib wafer 10 is not adsorbed by the transfer hand 30.

The threshold is a flow rate at which the minimum suction pressure for sucking and holding the rib wafer 10 can be maintained even if air flows into the ventilation hole of the transport hand 30. That means
The threshold value is determined when there is a gap between the suction hole 32 and the rib back surface 14 (see FIGS. 7 and 8).
This is a value for determining when all of the suction holes 32 are open (see FIG. 13) .

  Moreover, the determination method as described above may be applied to the transfer hand having the plurality of pipes 25 as described above, and the flow rate sensor 73 may be provided for each pipe 25. 1 may be applied to a transport hand in which a second ventilation hole and a vacuum generation source are connected by a single pipe 25. When applying to the conveyance hand which connected the hole for 2nd ventilation | gas_flowing, and the vacuum generation source with one piping 25, the one flow rate sensor 73 is provided in one piping 25, and the adsorption | suction state of a wafer is determined.

  As described above, according to the fifth embodiment, the same effects as in the first to fourth embodiments can be obtained. Further, based on the flow velocity of the air flowing through the inside of the transport hand 30 (the first ventilation hole 31 and the second ventilation hole 32), the presence or absence of a vacuum leak is determined, and the suction state of the rib wafer 10 is determined. For this reason, the suction hole 32 is not partially blocked by the rib back surface 14 and a gap is formed, but there is a sufficient suction force and the suction hole 32 is not blocked by the rib back surface 14 at all. It can be distinguished from a state where the force is insufficient. Thereby, it is possible to determine the case where the rib wafer 10 is reliably attracted to the transfer hand 30 and transfer the rib wafer 10. Therefore, the possibility that the rib wafer 10 falls can be reduced, and the occurrence of damage to the rib wafer 10 can be reduced.

(Embodiment 6)
FIG. 14 is an explanatory diagram of a wafer transfer mechanism unit according to the sixth embodiment. The transport hand shown in the fifth embodiment may further include a reversing unit that reverses the orientation of the device surface and the back surface of the rib wafer 10.

  In the sixth embodiment, as shown in FIG. 14, the transfer hand 30 (see FIG. 12) provided with a determination unit that determines the suction state of the rib wafer 10 is connected to a wafer transfer mechanism unit 80 such as a wafer transfer robot. Yes. The wafer transfer mechanism 80 includes a transfer mechanism main body 81, an arm 82, a reversing mechanism 83, a hand attachment 84, and a controller 85.

  The arm part 82 is supported by the transport mechanism main body 81 so as to be driven in the vertical direction and to be rotatable in a horizontal plane. Furthermore, the arm portion 82 can be driven to rotate in a horizontal plane at the end opposite to the end supported by the transport mechanism main body 81, separately from the rotational drive of the end supported by the transport mechanism main body 81. It has become. A reversing mechanism 83 that rotates the transport hand 30 in the vertical plane is supported at the end of the arm 82 opposite to the end supported by the transport mechanism main body 81. The reversing mechanism unit 83 rotates the transport hand 30 in a vertical plane, thereby reversing the orientation of the surface (suction surface) on which the wafer of the transport hand 30 is sucked and the surface opposite to the suction surface.

  The reversing mechanism 83 is connected to the transport hand 30 via a hand mounting portion 84. The control unit 85 is connected to the transport mechanism main body 81 and controls the arm unit 82, the reversing mechanism unit 83, the hand attachment unit 84, and the transport hand 30. The piping 25 is connected to a piping port (not shown) of the hand mounting portion 84. Further, the pipe 25 may be attached to the arm portion 82 so as to crawl the side surface of the arm portion 82. In this case, it is desirable that the pipe 25 be formed of a material having flexibility that can follow the operation of the arm portion 82. Other configurations are the same as those in the fifth embodiment.

  As described above, according to the sixth embodiment, the same effects as in the first to fifth embodiments can be obtained. Further, the wafer can be easily transferred and reversed while the wafer is attracted to the transfer hand 30. Thereby, it is possible to avoid the wafer from being damaged by human error.

(Embodiment 7)
FIG. 15 is a plan view of the wafer transfer apparatus according to the seventh embodiment. FIG. 16 is a cross-sectional view of the wafer transfer apparatus according to the seventh embodiment. The wafer transfer mechanism shown in the sixth embodiment may be provided in the wafer transfer device to control the transfer of the rib wafer.

  In the seventh embodiment, as shown in FIGS. 15 and 16, the wafer transfer device 180 includes a wafer transfer mechanism unit 80, wafer cassettes (wafer storage means) 91, 92, aligner (wafer alignment means) 93, and , An operation panel 181, a safety cover 182, a clean fan unit 183, a wafer cassette mounting base 184, a stand 185, a control unit 186, and a static eliminator 187.

  The wafer cassettes 91 and 92 store wafers that are taken in and out by the wafer transport mechanism 80. For the wafer cassettes 91 and 92, for example, different types of wafer cassettes having different dimensions, shapes, materials, and the like may be used. The first wafer cassette 91 stores, for example, wafers that are put into the manufacturing process. The second wafer cassette 92 stores, for example, wafers transferred from the first wafer cassette 91 or the aligner 93 during or after the manufacturing process. The aligner 93 aligns the wafer taken out from the first wafer cassette 91 by the wafer transfer mechanism 80, for example.

  The operation panel 181 sets information for controlling the wafer transfer device, such as the transfer pattern of the wafer cassette type, the movement depending on whether the wafer is reversed, and the wafer storage pattern. The safety cover 182 covers the wafer transfer mechanism unit 80 and prevents dust and dirt from adhering to the wafer. The clean fan unit 183 generates a descending airflow to drop dust and dirt that float above the wafer transfer mechanism 80 and prevent the dust and dirt from adhering to the wafer. Wafer cassettes 91 and 92 are mounted on the wafer cassette mounting base 184. Further, the wafer cassette mounting table 184 is provided with a sensor for identifying the type of the wafer cassettes 91 and 92.

  The gantry 185 supports equipment constituting the wafer transfer device 180 such as the wafer transfer mechanism unit 80 and the wafer cassette mounting table 184. Further, the gantry 185 is provided with wheels or the like so that the wafer transfer device 180 can move. The control unit 186 has a control program for controlling the wafer transfer apparatus and controls the wafer transfer apparatus. The control unit 186 includes a control unit (see FIG. 15) provided in the wafer transfer mechanism unit 80, for example. The static eliminator 187 removes static electricity charged on the transfer hand provided in the wafer transfer mechanism unit 80, and prevents dust and dirt from adhering to the wafer. The configuration of the wafer transfer mechanism 80 is the same as that of the sixth embodiment (see FIG. 14).

  Such a wafer conveyance device 180 conveys a wafer as follows. First, the wafers stored in the first wafer cassette 91 are vacuum-sucked in suction holes provided in the transfer hand of the wafer transfer mechanism unit 80 and taken out from the first wafer cassette 91 to the outside. Next, the wafer is transferred to the aligner 93 by the wafer transfer mechanism 80. Next, the wafer is mounted on a table provided in the aligner 93 and the notch position of the wafer is aligned. Next, the wafer is vacuum-sucked in a suction hole provided in the transport hand of the wafer transport mechanism unit 80, and the wafer is taken out of the aligner 93. Next, the wafer is transferred from the aligner 93 to the second wafer cassette 92 by the wafer transfer mechanism 80 and stored.

  In each process described above, the wafer suction state may be determined after the wafer is sucked by the transfer hand and before the wafer is transferred. For example, after the wafer in the first wafer cassette 91 is adsorbed by the transfer hand and before being taken out from the first wafer cassette 91, the flow rate sensor (see FIGS. 12 and 14) is used to set the ventilation hole of the transfer hand. Measure the flow velocity of the air flowing inside. Next, it is determined by the flow rate sensor whether or not the wafer is adsorbed to the transfer hand based on the flow rate inside the ventilation hole. The method for determining the wafer suction state is the same as in the fifth embodiment.

  Moreover, in each process mentioned above, you may reverse the direction of a wafer by the inversion mechanism part (refer FIG. 14), before conveying a wafer to the following process. Further, the wafer may be transported by adsorbing the peripheral portion along the outer periphery of the wafer with the transport hand. In the transfer method described above, a rib wafer (see FIG. 19) may be transferred. In this case, the wafer may be transported by sucking the rib back surface of the rib wafer with the transport hand.

  As described above, according to the seventh embodiment, the same effects as in the first to sixth embodiments can be obtained.

(Example)
FIG. 17 is a characteristic diagram showing the relationship between the flow velocity flowing inside the transfer hand and the wafer adsorption state. FIG. 18 is a characteristic diagram showing the relationship between the pressure inside the transfer hand and the wafer suction state. First, according to the first embodiment, the back surface of the rib wafer is sucked by the transport hand, and three types of samples having different suction positions of the rib portion to the transport hand are prepared (hereinafter referred to as the first sample to the third sample). . Here, the width of the suction hole of the transport hand is set to 2.0 mm. In the first sample, the suction hole was completely closed by the back surface of the rib, and there was no gap (see FIG. 6). In the second sample, the suction hole was not partially blocked by the back surface of the rib, and a gap of 0.5 mm was generated (see FIGS. 7 and 8). In the third sample, the suction hole was not completely blocked by the rib back surface (see FIG. 13). That is, the third sample has a 2.0 mm gap.

  A plurality of the above-described samples were prepared, and the flow velocity of the air flowing inside the transport hand was measured according to the determination method shown in Embodiment 5 (see FIG. 12). The threshold value is set to 18.0 to 18.3 m / s at which the minimum suction pressure for sucking and holding the rib wafer can be maintained. As a comparison, the pressure inside the transfer hand was measured using the same sample described above according to a conventional determination method (see FIG. 28).

  From the results shown in FIG. 17, in the first sample and the second sample, the air flowing inside the transfer hand has a flow velocity equal to or lower than the threshold value. Moreover, the 1st sample and the 2nd sample were adsorb | sucked by the conveyance hand. Thereby, it was found that the suction state of the wafer can be determined based on the flow velocity flowing inside the transfer hand. Further, from the results shown by the second sample, it is understood that the rib wafer can be adsorbed to the conveyance hand even when a gap is generated between the suction hole and the rib back surface based on the flow velocity flowing inside the conveyance hand. It was.

  On the other hand, in the third sample, the air flowing inside the transfer hand had a flow velocity larger than the threshold value. Moreover, the 3rd sample was not adsorbed by the conveyance hand. Thereby, based on the flow velocity flowing inside the transport hand, when a gap is generated between the suction hole and the back surface of the rib (second sample), or when all the suction holes are opened (third sample). It was found that can be discriminated.

  On the other hand, in the result shown in FIG. 18, the first sample had a higher adsorption pressure. Furthermore, it can be clearly seen that the first sample has a higher adsorption pressure than the second sample and the third sample. Moreover, the 1st sample was adsorb | sucked by the conveyance hand. On the other hand, the second sample and the third sample had substantially the same adsorption pressure. Further, the second sample was adsorbed by the transport hand. The third sample was not adsorbed by the transport hand. That is, when the suction hole is completely closed by the rib back surface as in the first sample, the wafer suction state can be determined based on the pressure inside the transfer hand. However, when a vacuum leak occurs regardless of the width of the gap as in the second sample and the third sample, there is no clear difference in the pressure inside the transport hand, so it is based on the pressure inside the transport hand. Thus, it can be seen that the suction state of the wafer cannot be determined.

  In the present invention, the handling of the rib wafer is described as an example. However, the present invention is not limited to the above-described embodiment, and can be applied to the handling of a flat wafer. In the determination of the wafer suction state, the flow velocity inside the transfer hand is measured. However, the flow velocity inside the transfer hand may be measured.

  As described above, the wafer transfer apparatus and the wafer transfer method according to the present invention are useful when transferring a rib wafer having a thin wafer thickness, a wafer having an element structure formed on the front surface or the back surface, and the like.

2 The part where the element structure of the front surface of the wafer is formed (device surface)
DESCRIPTION OF SYMBOLS 3 Wafer back surface 10 Rib wafer 11 The part where the element structure of the front surface of a rib wafer is not formed 12 Rib part 13 The center part of the rib wafer back surface 14 Rib part back surface 24 Step part 25 Piping 26 Vacuum generation source 30 Transfer hand 32 Adsorption hole 31 33 Ventilation holes

Claims (7)

Have a plurality of suction holes for sucking the wafer, and conveying means for supporting part for supporting the wafer in contact with the region where the element structure of the wafer is not formed is provided,
Inside provided with a plurality spaced apart from each other of said conveying means, and holes for ventilation each connected to at least one of said suction holes,
A vacuum generating means connected to the ventilation hole and evacuating the inside of the ventilation hole ;
A flow velocity measuring means for measuring a flow velocity of air flowing inside the ventilation hole of the conveying means which is evacuated by the vacuum generating means;
An adsorption determination unit that determines whether or not a wafer is adsorbed to the transfer unit based on the flow rate measured by the flow rate measurement unit;
Equipped with,
Before Symbol supporting portion of said conveying means, at a portion facing the wafer, and than the portion not in contact with the wafer protrudes to the wafer side, left thicker the conveying means along the outer periphery of the wafer A wafer transfer apparatus, wherein the wafer transfer device is provided at a position overlapping with the peripheral portion when the peripheral portion is matched with the surface forming the step shape .   2. The wafer transfer apparatus according to claim 1, wherein the ventilation holes are connected to different suction holes. The wafer transfer device according to claim 1 or 2, characterized in that obtaining Bei inverting means for inverting the surface of the wafer adsorbed to the conveying means inside out before Symbol conveying means. A wafer storage means for storing the wafer to be out by the conveyance means,
And a wafer alignment means to align the wafer taken out from the wafer storage means by the previous Ki搬 feeding means,
The wafer transfer apparatus according to any one of claims 1 to 3, further comprising: Element structure is not formed, of the wafer peripheral portion is left thicker along the outer periphery surface of the peripheral portion of the side forming the stepped shape is in contact with the supporting portion of the conveying means by the peripheral portion, in contact the the surface of the peripheral portion, those the support portion provided on and adsorbed to a plurality of suction holes that can be evacuated independently of one another, the flow through vacuum suction holes in the adsorption of the wafer on the suction hole measuring the flow rate of the air, to determine the extent of adsorption of the wafer on the basis of the measurement result, after the determination, in a state of being adsorbed wafer transfer method characterized by conveying the person the wafer.   The surface of the peripheral part where the peripheral part is thickly formed along the outer periphery of the wafer where the element structure is not formed, the surface of the peripheral part on the surface side forming a step shape by the peripheral part comes into contact with the support part of the transport means, and the peripheral part in contact The surface of the part is adsorbed by a plurality of suction holes provided in the support part and capable of being evacuated independently of each other, and when the wafer is sucked by the suction hole, The flow rate is measured, the degree of wafer adsorption is determined based on the measurement result, and after the determination, the orientation of the wafer is reversed in the adsorbed state, and the wafer is conveyed after the inversion. Wafer transfer method. 7. The wafer transfer method according to claim 5, wherein all the suction holes are evacuated independently of each other.

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