JP2011061120A - Method of carrying wafer and wafer carrying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of carrying wafers and a wafer carrying device capable of separating the semiconductor wafers one by one without using manpower after cutting, for example, by a wire saw. <P>SOLUTION: The method of carrying wafers for carrying a plurality of stacked wafers Wf includes a process for jetting a liquid Lq toward the end face of the plurality of wafers Wf to generate a gap among the plurality of wafers Wf positioned within the liquid Lq and a process for picking up the wafers Wf positioned at least at the uppermost part from among the plurality of wafers Wf while the gap has been generated. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wafer transfer method and a wafer transfer apparatus for transferring semiconductor wafers used, for example, as materials for solar cells one by one.

  FIG. 15 shows a cutting process using a wire saw device in the manufacture of a semiconductor wafer (see, for example, Patent Document 1). The wire saw apparatus X shown in the figure includes four guide rollers 93 and wires 94, and is an apparatus that cuts the semiconductor material 92 into a wafer. The wire 94 is, for example, a piano wire plated, is wound around four guide rollers 93, and is sent in the direction of the illustrated arrow. The semiconductor material 92 is pressed against the wire 94 in a state where it is bonded to a holding member 91 made of glass, for example, with an adhesive. When the wire 94 reaches the holding member 91 beyond the semiconductor material 92, the cutting of the semiconductor material 92 is completed. By this cutting, a plurality of wafers are obtained in a state where the respective edges are joined to the holding member 91.

  However, after finishing the cutting, it is necessary to finally separate the wafers one by one. Prior to this separation operation, the wafer is immersed in a solution that dissolves the cleaning liquid and the adhesive for the purpose of cleaning the cutting powder and peeling from the holding member 91. When the wafers are wet by these liquids, the wafers that are adjacent to each other are likely to stick to each other. For this reason, it is not easy to separate the wafers one by one. For example, an operator is forced to manually pick up the semiconductor wafers one by one.

JP 2007-160431 A

  The present invention has been conceived under the circumstances described above. For example, a wafer transfer method and wafer transfer capable of separating semiconductor wafers one by one after being cut by a wire saw without human intervention. An object is to provide an apparatus.

  A wafer transfer method provided by the first aspect of the present invention is a wafer transfer method for transferring a plurality of stacked wafers, and is provided between any of the plurality of wafers positioned in a liquid. A step of ejecting the liquid toward the end surfaces of the plurality of wafers in order to generate a gap, and a step of picking up a wafer positioned at least on the top of the plurality of wafers in a state in which the gap is generated It is characterized by providing these.

  In a preferred embodiment of the present invention, the step of ejecting the liquid includes a first step of ejecting the liquid toward the center of the end surface in the extending direction of the end surface of the wafer.

  In a preferred embodiment of the present invention, the step of ejecting the liquid includes the first step of ejecting the liquid from the position overlapping the end surface toward the end surface in the extending direction of the end surface of the wafer. A different second step is further included.

  In a preferred embodiment of the present invention, the direction in which the liquid is ejected in the first step is the same as the direction in which the liquid is ejected in the second step.

  In a preferred embodiment of the present invention, the liquid ejected in the first and second steps is ejected from the same position in the wafer stacking direction.

  In a preferred embodiment of the present invention, the step of ejecting the liquid further includes a third step of ejecting the liquid from the outside of the end surface in the direction in which the end surface of the wafer extends toward the end surface.

  In a preferred embodiment of the present invention, in the third step, the liquid is ejected toward the upper side of the uppermost wafer.

  In a preferred embodiment of the present invention, in the wafer stacking direction, the liquid ejected in the first step is ejected from a position lower than the position where the liquid is ejected in the third step.

  In a preferred embodiment of the present invention, in the step of ejecting the liquid, the liquid is ejected in a flat shape along the stacking direction of the wafers.

  In a preferred embodiment of the present invention, the step of ejecting the liquid is continuously performed before and after the step of picking up the wafer.

  In a preferred embodiment of the present invention, the top wafer among the plurality of wafers is sucked in an in-plane direction while the top wafer is sucked, and the wafer is sequentially moved from the top wafer. The method further includes a step of transporting the wafer.

  In a preferred embodiment of the present invention, the suction slide means includes a pair of rollers spaced apart from each other and an endless belt wrapped around the pair of rollers, and the endless belt is surrounded by the endless belt. A plurality of holes connected to a space that can be decompressed are provided.

  In a preferred embodiment of the present invention, in the step of ejecting the liquid, the liquid is ejected from the front side of the wafer in the sliding direction with respect to the plurality of wafers.

  The wafer transfer apparatus provided by the second aspect of the present invention is a wafer transfer apparatus for transferring a plurality of stacked wafers, and the liquid is directed toward the end faces of the plurality of wafers located in the liquid. And at least one liquid ejecting means for creating a gap between any of the plurality of wafers, and at least the uppermost of the plurality of wafers in a state where the gap is created. And a wafer receiving means capable of receiving a positioned wafer.

  In a preferred embodiment of the present invention, the at least one liquid ejecting means includes first liquid ejecting means for ejecting the liquid toward the center of the end face in the extending direction of the end face of the wafer.

  In a preferred embodiment of the present invention, the at least one liquid ejecting means is disposed at a position overlapping the end face in the extending direction of the end face and ejects the liquid toward the end face. Second liquid ejecting means different from the ejecting means is further included.

  In a preferred embodiment of the present invention, both the first and second liquid ejecting means eject the liquid in the same direction.

  In a preferred embodiment of the present invention, the first liquid ejecting means and the second liquid ejecting means are located in the same direction in the wafer stacking direction.

  In a preferred embodiment of the present invention, the at least one liquid ejecting means further includes third liquid ejecting means for ejecting the liquid from the outside of the end face in the extending direction of the end face toward the end face.

  In a preferred embodiment of the present invention, the third liquid ejecting means further ejects the liquid toward the upper side of the uppermost wafer.

  In a preferred embodiment of the present invention, the first liquid ejecting means is positioned lower than the third liquid ejecting means in the wafer stacking direction.

  In a preferred embodiment of the present invention, any one of the at least one liquid ejecting means ejects the liquid having a flat shape along the wafer stacking direction.

  In a preferred embodiment of the present invention, the wafer receiving means includes suction slide means for sliding the wafer in the in-plane direction with the uppermost one of the plurality of wafers being sucked.

  In a preferred embodiment of the present invention, the suction slide means includes a pair of rollers spaced apart from each other and an endless belt wrapped around the pair of rollers, and the endless belt is surrounded by the endless belt. A plurality of holes connected to a space that can be decompressed are provided.

  In a preferred embodiment of the present invention, the at least one liquid ejecting means is arranged on the front side in the sliding direction of the wafer with respect to the plurality of wafers.

  According to such a configuration, in the plurality of wafers stacked in the liquid, a gap is generated between the plurality of wafers by ejecting the liquid onto the end surfaces of the wafers. Be made. Therefore, the uppermost wafer among the plurality of wafers is positioned higher than before the liquid is ejected. Thereby, it is possible to appropriately pick up the wafer positioned at the top.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

1 is an overall schematic diagram illustrating an example of a wafer transfer apparatus according to the present invention. It is principal part sectional drawing which shows the wafer conveyance apparatus shown in FIG. FIG. 2 is a perspective view showing only a part of the configuration of the wafer transfer apparatus shown in FIG. 1. It is principal part sectional drawing in alignment with the IV-IV line of FIG. It is the top view seen from the upper side of FIG. It is the principal part perspective view which looked at the adsorption conveyor of the wafer conveyance apparatus shown in FIG. 1 from diagonally downward. It is principal part sectional drawing which shows the process of levitating a wafer in the wafer conveyance method which concerns on this invention. FIG. 7 is a perspective view of relevant parts similar to FIG. 6, showing a step of floating a wafer in the wafer transfer method according to the present invention. FIG. 7 is a perspective view of essential parts similar to FIG. 6, showing a process of sucking a wafer in the wafer transfer method according to the present invention. In the wafer conveyance method concerning this invention, it is principal part sectional drawing which shows the process of adsorb | sucking a wafer. It is principal part sectional drawing which shows the process of sliding a wafer in the wafer conveyance method which concerns on this invention. FIG. 7 is a perspective view of essential parts similar to FIG. 6, showing a step of sliding the wafer in the wafer transfer method according to the present invention. In the wafer conveyance method which concerns on this invention, it is principal part sectional drawing which shows the process of delivering a wafer to a relay conveyor. It is principal part sectional drawing which shows the last process in the wafer conveyance method concerning this invention. It is a perspective view which shows the cutting process of the semiconductor material using a wire saw apparatus.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  FIG. 1 shows an example of a wafer transfer apparatus according to the present invention. The wafer transfer apparatus A according to this embodiment includes a wafer tank 1, a suction conveyor 2, a plurality of nozzles 31, a sponge roller 32, a heater 41, a temperature sensor 42, a heater control unit 43, a relay conveyor 5, a loading conveyor 6, a stacker 7, A mounting table 81 and a support member 82 are provided.

  The wafer tank 1 is formed in a container shape that opens upward in the vertical direction, and accommodates a plurality of wafers Wf in a state of being immersed in a predetermined liquid Lq. The plurality of wafers Wf are mounted on a mounting table 81 described later and guided by a support member 82. The plurality of wafers Wf are placed in the liquid Lq in a state where they are stacked up and down, and are inclined at a predetermined angle with respect to the liquid level Ls of the liquid Lq. The liquid Lq is obtained by mixing an appropriate amount of a surfactant in water, for example. The number of wafers Wf is, for example, about 1000. As an example of the dimensions of the wafer Wf, the outer shape is 156 mm square and the thickness is 0.14 to 0.18 mm. The plurality of wafers Wf are stacked so that the upper surface of the wafer Wf is parallel to a wafer suction surface 22c of the suction conveyor 2 described later. The distance between the upper surface of the uppermost wafer Wf and the wafer suction surface 22c of the suction conveyor 2 is, for example, 15 to 35 mm.

  FIG. 3 is a perspective view showing only the mounting table 81 and the support member 82 in a partially transparent manner. 4 is a cross-sectional view of a principal part taken along the line IV-IV in FIG. FIG. 5 shows a plan view seen from the upper side of FIG.

  The mounting table 81 is for mounting a plurality of wafers Wf. The mounting table 81 is made of, for example, vinyl chloride resin or glass epoxy resin. As shown in FIGS. 3 and 4, the mounting table 81 includes a bottom portion 811, a pair of plate-like members 812 and 813, and an auxiliary support member 814. The bottom portion 811 has a square flat plate shape. The outer shape of the bottom portion 811 is approximately the same size as the wafer Wf and has a thickness of, for example, 10 mm.

  Each of the pair of plate-like members 812 and 813 and the auxiliary support member 814 stands from the bottom portion 811 toward the upper side of FIGS. The pair of plate-like members 812 and 813 and the auxiliary support member 814 are arranged in parallel to each other and have a long plate shape extending along the x1-x2 direction. The pair of plate-like members 812 and 813 and the auxiliary support member 814 are all for supporting the wafer Wf. Even if only a pair of plate-like members 812 and 813 is disposed, a plurality of wafers Wf can be supported. However, by further disposing the auxiliary support member 814, it is possible to suppress the wafer Wf from being bent downward. The dimensions of the pair of plate-like members 812 and 813 and the auxiliary support member 814 are, for example, a long side of 156 mm, a short side of 15 to 35 mm, and a thickness of 2 to 10 mm.

  In the mounting table 81, two spaces 815 are formed by being sandwiched between the bottom base portion 811, the pair of plate-like members 812 and 813, and the auxiliary support member 814. The space 815 penetrates in the x1-x2 direction. In addition, the space 815 is exposed toward the side opposite to the bottom portion 811, that is, the side on which the wafer Wf is placed.

  The support member 82 is for guiding the plurality of wafers Wf so that the plurality of wafers Wf are not displaced. In the present embodiment, the support member 82 is connected to the mounting table 81.

  The support member 82 is made of, for example, glass epoxy resin or stainless steel. As illustrated in FIGS. 3 to 5, the support member 82 includes a pair of movement restriction portions 821 and 822 and movement restriction portions 823 and 824. All of the movement restricting portions 821 and 822 are arranged on the direction x1 side with respect to the plurality of wafers Wf. By thus disposing the movement restricting portions 821 and 822, the movement of the plurality of wafers Wf in the direction x1 is restricted. The movement restricting portions 821 and 822 have a long plate shape extending along the stacking direction of the wafers Wf. The movement restricting portions 821 and 822 are separated from each other, and the separation distance L1 is, for example, 101 to 140 mm. Further, the separation distance is smaller than the width of the wafer Wf.

  The movement restricting portion 823 is disposed on the direction y1 side with respect to the plurality of wafers Wf, and the movement restricting portion 824 is disposed on the direction y2 side with respect to the plurality of wafers Wf. By arranging the movement restricting portions 823 and 824 in this manner, the movement of the plurality of wafers Wf in the y1-y2 direction is restricted. The movement restricting portions 823 and 824 have a long plate shape extending along the stacking direction of the wafers Wf. The movement restricting portion 823 is integrally formed with the movement restricting portion 821, and the movement restricting portion 824 is integrally formed with the movement restricting portion 824.

  The plurality of wafers Wf are, for example, stacked on the table 81 on the left side of the wafer tank 1 in FIG. 1 and guided by the support member 82, and are sent to the right part of the wafer tank 1 in the drawing by the conveyor 11. Are handled. The lifter 12 can be raised and lowered with an accuracy corresponding to at least the thickness of one wafer Wf by, for example, a servo motor (not shown). As the lifter 12 moves up and down, the mounting table 81, the support member 82, and the wafer Wf move up and down.

  The suction conveyor 2 corresponds to an example of the suction slide means referred to in the present invention, and is provided in a position where the lower part of the wafer tank 1 is immersed in the liquid Lq. As shown in FIG. 5, the size L2 of the suction conveyor 2 in the y1-y2 direction is smaller than the separation distance L1 between the movement restricting portions 821 and 822, for example, 100 mm. As shown in FIG. 2, the suction conveyor 2 includes a pair of rollers 21, a pair of endless belts 22, and a vacuum box 23.

  The pair of rollers 21 are spaced apart from each other in parallel, and at least one of them is connected to a drive source such as a servo motor (not shown). In the present embodiment, the roller 21 shown in FIG. 2 is rotated counterclockwise in the drawing.

  The pair of endless belts 22 are, for example, rubber belt-like belts that are annular, and are wound around the pair of rollers 21. As shown in FIG. 6, the pair of endless belts 22 are spaced apart from each other in parallel. As shown in FIGS. 2 and 6, a plurality of holes 22 b are formed in the suction section 22 a which is a part of each endless belt 22 in the circumferential direction. Each hole 22b penetrates the endless belt 22 in its thickness direction, and allows liquid Lq and air to pass through. In the present embodiment, the circumferential dimension of the suction section 22a is substantially the same as the circumferential dimension of the wafer Wf.

  As shown in FIG. 2, the vacuum box 23 is disposed in the inner space of the endless belt 22 and is a box made of, for example, SUS having a rectangular cross section. The dimension in the height direction of the vacuum box 23 is substantially the same as the interval between the inner sides of the endless belt 22. For this reason, the endless belt 22 slides along the upper and lower surfaces of the vacuum box 23. Each endless belt 22 is rotated in the direction of the arrow (counterclockwise) in FIG. That is, when the roller 21 is driven to rotate, a portion of the endless belt 22 positioned below the vacuum box 23 (wafer suction surface 22c) slides from left to right in the drawing.

  The vacuum box 23 has three compartments 231, 232 and 233. These compartments 231, 232 and 233 are arranged along the direction in which the pair of rollers 21 are separated. A plurality of holes 23 b are formed in the vacuum box 23. The plurality of holes 23b are provided in the lower portion of the vacuum box 23. In the present embodiment, the plurality of holes 23b are provided in substantially the entire lower portion of the vacuum box 23. The compartments 231, 232, and 233 are each provided with an air inlet 23a.

  As clearly shown in FIG. 2, the suction conveyor 2 is inclined slightly with respect to the liquid level Ls of the liquid Lq. More specifically, the suction conveyor 2 is inclined so that the right end is higher than the left end.

  A pump 26 is connected to the intake port 23a through a hose 24, a valve unit 27, and a dehydration tank 25. The hose 24 is a flexible piping component made of resin, for example. The valve unit 27 can switch which of the compartments 231, 232, and 233 is connected to the pump 26. The dewatering tank 25 is for separating the liquid Lq from the air sucked through the vacuum box 23. The pump 26 is a depressurization source for depressurizing the space in the vacuum box 23 accommodated in the endless belt 22 to such an extent that the wafer Wf can be adsorbed by the adsorption conveyor 2.

  The plurality of nozzles 31 are components that discharge the liquid Lq, and generate a jet of the liquid Lq. Each of these nozzles 31 is connected to a discharge pump (not shown) via a pipe (not shown). In the present embodiment, as shown in FIG. 2, the nozzle 31 is arranged on the right side in the drawing with respect to the stacked wafers Wf, and the liquid is directed toward the end faces Wfa of the plurality of wafers Wf. It is provided in a posture for ejecting Lq. Any of the nozzles 31 can eject a liquid Lq having a flat shape in the stacking direction of the wafers Wf (not shown). The flow rate of the liquid Lq discharged from the nozzle 31 is, for example, about 9 L / min.

  A detailed arrangement state of the plurality of nozzles 31 will be described with reference to FIGS. 4 and 5. In these drawings, the nozzle 311 is arranged at the center in the y1-y2 direction, the nozzle 312 is adjacent to the nozzle 311, and the nozzle 313 is arranged at the outermost side in the y1-y2 direction.

  The nozzle 311 ejects the liquid Lq toward the center of the end surface Wfa of the wafer Wf in the y1-y2 direction (the direction in which the end surface Wfa of the wafer Wf extends). The position at which the jet flow from the nozzle 311 hits the end face Wfa of the wafer Wf is a position corresponding to several sheets (about 5 to 6 sheets) from the uppermost one of the plurality of wafers Wf. The direction in which the nozzle 311 ejects the liquid Lq coincides with the direction x1. The nozzle 312 is disposed at a position overlapping the end surface Wfa of the wafer Wf in the y1-y2 direction. Further, as shown in FIG. 4, the nozzle 312 is disposed at the same position as the nozzle 311 in the stacking direction of the wafer Wf. The nozzle 312 ejects the liquid Lq toward a portion near one end of the end face Wfa of the wafer Wf. The position where the jet flow from the nozzle 312 hits the end face Wfa of the wafer Wf is a position of several sheets (about 5 to 6 sheets) from the uppermost one of the plurality of wafers Wf. The direction in which the nozzle 312 ejects the liquid Lq also coincides with the direction x1.

  As shown in FIGS. 4 and 5, the nozzle 313 is disposed outside the end face Wfa of the wafer Wf in the y1-y2 direction. As shown in FIG. 4, the nozzle 313 is arranged higher than the nozzles 311 and 312 in the wafer Wf stacking direction. The nozzle 313 ejects the liquid Lq slightly upward toward the vicinity of one end of the end face Wfa of the wafer Wf. Preferably, the nozzle 313 may eject the liquid Lq toward the upper side of the uppermost one of the plurality of wafers Wf and so that the jet flow from the nozzle 313 reaches the adsorption conveyor 2. The ejection direction of the liquid Lq from the nozzle 313 is, for example, 15 to 20 degrees with respect to the in-plane direction of the wafer Wf.

  The sponge roller 32 is a roller whose surface is made of sponge. The sponge roller 32 is disposed rightward in the drawing with respect to the plurality of stacked wafers Wf immediately below the suction conveyor 2. The sponge roller 32 is connected to a motor (not shown), for example, and is rotatable. In the present embodiment, the sponge roller 32 is fixed to the suction conveyor 2 by a bracket.

  As shown in FIG. 1, the heater 41 is immersed in the liquid Lq, and is disposed, for example, near the wall surface of the wafer tank 1. As the heater 41, a liquid heating one is used. When the heater 41 is driven, the liquid Lq is heated and the temperature of the liquid Lq rises. The heater 41 is connected to the heater control unit 43 via a cable, and its driving is controlled by an electric signal from the heater control unit 43.

  The temperature sensor 42 is immersed in the liquid Lq, and is disposed, for example, near the wall surface of the wafer tank 1. As the temperature sensor 42, for example, a thermistor for measuring a liquid temperature can be employed. An output signal from the temperature sensor 42 is transmitted to the heater control unit 43 via a cable.

  The heater control unit 43 is for supplying driving power to the heater 41 and is provided outside the wafer tank 1. The heater control unit 43 includes a control circuit that controls driving of the heater 41 in accordance with an electrical signal from the temperature sensor 42. Examples of the control by the heater control unit 43 include so-called feedback control that controls the driving of the heater 41 so that the temperature measured by the temperature sensor 42 falls within a predetermined temperature range.

  The relay conveyor 5 is disposed above the liquid level Ls on the downstream side of the suction conveyor 2. The relay conveyor 5 receives the wafer Wf sucked by the procedure described later from the suction conveyor 2.

  The loading conveyor 6 is disposed on the downstream side of the relay conveyor 5. The loading conveyor 6 is used to load the wafer Wf received from the relay conveyor 5 into the stacker 7.

  The stacker 7 is for storing a plurality of wafers Wf one by one, and has a plurality of pockets 71 arranged in parallel to each other in the vertical direction. When the wafer Wf is sent from the loading conveyor 6, the wafer Wf is loaded into a pocket 71. Then, the stacker 7 is raised by one step of the pocket 71 by lifting means (not shown). As a result, the next wafer Wf can be loaded.

  Next, an example of the wafer transfer method according to the present invention will be described below with reference to FIGS. In FIG. 7 to FIG. 13, the description of the mounting table 81 and the support member 82 is omitted for the sake of easy understanding, but actually, a plurality of wafers Wf are mounted on the mounting table 81 and guided to the support member 82. The following steps are performed as they are.

  First, as shown in FIG. 7, the suction section 22a of the endless belt 22 is positioned immediately above the stacked wafers Wf. At this time, the distance between the upper surface of the uppermost wafer Wf and the wafer suction surface 22c of the suction conveyor 2 is, for example, 15 to 35 mm. When the adsorption section 22a is at this position, the plurality of holes 23b of the vacuum box 23 provided in the compartments 231 and 232 overlap the adsorption section 22a. At this time, by switching the valve unit 27, the compartments 231 and 232 and the pump 26 are connected, and the compartment 233 and the pump 26 are shut off. At the same time, the pump 26 is driven, and the internal pressure of the compartments 231 and 232 is set to a negative pressure. Here, the temperature of the liquid Lq is set to 30 ° C. or higher in advance by driving the heater 41.

  Next, the liquid Lq is ejected from the plurality of nozzles 31 toward the end face Wfa of the wafer Wf at a predetermined discharge pressure (see FIGS. 4 to 6). The liquid Lq enters between the wafers Wf or above the uppermost portion of the wafer Wf at the part where the liquid Lq is sprayed by the discharge pressure from the nozzle 31. Then, as shown in FIG. 8, the plurality of wafers Wf including the uppermost wafer Wf are lifted so that a gap is formed between them. The uppermost wafer Wf is close to the suction section 22a (wafer suction surface 22c) of the endless belt 22.

  In the suction conveyor 2, since the internal pressure of the compartments 231 and 232 is negative, the uppermost wafer Wf in the vicinity immediately below the suction section 22a is drawn upward. Then, as shown in FIGS. 9 and 10, the uppermost wafer Wf is sucked into the suction section 22a.

  Next, the ejection of the liquid Lq from the nozzle 31 is stopped. Then, as shown in FIGS. 11 and 12, by driving the roller 21, the endless belt 22 is rotated counterclockwise. Thereby, the attracted wafer Wf is slid rightward in the figure. At this time, the sponge roller 32 is rotated counterclockwise. Then, the sliding wafer Wf passes through the top of the sponge roller 32 in order from the tip while contacting the wafer Wf. As a result, a resistance force is applied to the wafer Wf in the direction opposite to the sliding direction. If two wafers Wf that are positioned at the top and the wafer Wf that is directly below them are mistakenly taken, the lower wafer Wf can be removed by this resistance force. Furthermore, the surfactant mixed in the liquid Lq suitably promotes the penetration of the liquid Lq between the two wafers Wf. In the present description, the ejection of the liquid Lq from the nozzle 31 is stopped, but the following series of steps may be continued without stopping the ejection of the liquid Lq from the nozzle 31.

  When the endless belt 22 circulates, the suction section 22a moves from a position overlapping the compartments 231 and 232 to a position overlapping the compartments 232 and 233. At this time, as clearly shown in FIG. 11, by switching the valve unit 27, the compartments 232 and 233 and the pump 26 are connected, and the compartment 231 and the pump 26 are shut off. As a result, the internal pressure of the compartments 232 and 233 becomes negative, and the compartment 231 is released from the state where the internal pressure becomes a strong negative pressure.

  Next, as shown in FIG. 13, the endless belt 22 is further circulated. Then, the attracted wafer Wf slides further to the right and is delivered to the relay conveyor 5. In the illustrated state, the adsorption section 22a overlaps only the compartment 233. At this time, by switching the valve unit 27, the compartment 233 and the pump 26 are connected, and the compartments 231 and 232 and the pump 26 are shut off.

  Thereafter, the wafer Wf is loaded into the stacker 7 via the relay conveyor 5 and the loading conveyor 6. On the other hand, the suction conveyor 2 is brought into the state shown in FIG. 7 again by rotating the endless belt 22 and switching the valve unit 27. Then, the lifter 12 raises the stacked plurality of wafers Wf by a height corresponding to the thickness of the single wafer, so that the next wafer Wf can be adsorbed. By sequentially repeating the steps described above, a plurality of stacked wafers Wf can be transferred one by one and loaded into the stacker 7.

  As a result of sequentially repeating the above steps, finally, as shown in FIG. 14, the number of wafers Wf mounted on the mounting table 81 is about several. When the number of wafers Wf is about several, the liquid Lq ejected from the nozzle 31 toward the end surface Wfa of the wafer Wf also enters the space 815 of the mounting table 81 on which the wafer Wf is placed. Therefore, even if there are several wafers Wf, they float up so that a gap is formed between them. Thereafter, through the same process as described above, almost all of the wafers Wf placed on the placing table 81 can be loaded into the stacker 7.

  Next, the operation of the wafer transfer method and wafer transfer apparatus A of this embodiment will be described.

  The plurality of wafers Wf are in a wet state because, for example, a cutting process using a wire saw is followed by a cleaning process and an adhesive dissolving process. When these wet wafers Wf are placed in the atmosphere, they stick to each other and it is difficult to separate them one by one. According to the present embodiment, in the plurality of wafers Wf stacked in the liquid Lq, the plurality of wafers Wf including the uppermost wafer Wf are ejected by ejecting the liquid Lq to the end faces Wfa of the wafers Wf. A gap is created between the two. That is, since there is a gap between the uppermost wafer Wf and the wafer Wf immediately below the uppermost wafer Wf, the state where the wafers Wf are stuck to each other is eliminated, and the wafer Wf located at the uppermost position is appropriately sucked by the conveyor. 2 can be adsorbed.

  Furthermore, in the present embodiment, the nozzle 31 is arranged as shown in FIGS. 4 and 5 and the direction of the liquid Lq ejected from the nozzle 31 is adjusted, so that there is a gap between the plurality of wafers Wf. It is easy to cause.

  According to the tests by the inventors, according to the present embodiment, it is easier to create a gap between more wafers Wf than in the case where the nozzle 311 is not provided, and the wafers Wf can be floated faster. I was able to. In addition, the plurality of wafers Wf can be floated more reliably than in the case where the nozzle 312 or the nozzle 313 is not provided.

  As shown in the figure, it is not always necessary to dispose any of the nozzles 311, 312 and 313 as the nozzle 31. For example, as the nozzle 31, only the nozzles 311 and 312 may be arranged, only the nozzles 311 and 313 may be arranged, or only the nozzles 312 and 313 may be arranged. Alternatively, only the nozzle 311, only the nozzle 312, or only the nozzle 313 may be disposed as the nozzle 31.

  Any of the nozzles 31 can eject the liquid Lq having a flat shape in the stacking direction of the wafers Wf. This also facilitates the formation of a gap between the plurality of wafers Wf.

  As shown in FIGS. 4 and 5, the plurality of wafers Wf are guided by the support member 82. In particular, the movement of the plurality of wafers Wf in the direction x1 is restricted by the pair of movement restricting portions 821 and 822. Therefore, even when the liquid Lq is ejected from the nozzle 31 toward the direction x1 with respect to the wafer Wf, the wafer Wf is less likely to be displaced in the direction x1 due to the force of the liquid Lq. Such a configuration is suitable for accurately adsorbing the uppermost wafer Wf. Further, the movement of the wafer Wf in the direction y1 and the direction y2 is restricted by the pair of movement restricting portions 823 and 824. Such a configuration is also suitable for accurately adsorbing the uppermost wafer Wf. In the above embodiment, the pair of movement restricting portions 821 and 822 is an example of a separate plate-like member, but the pair of movement restricting portions 821 and 822 are two portions of an integral member. It doesn't matter.

  The size L2 of the suction conveyor 2 in the y1-y2 direction is smaller than the separation distance L1 between the movement restricting portions 821 and 822. Therefore, as shown in FIG. 14, the suction conveyor 2 can move in the stacking direction of the plurality of wafers Wf without being obstructed by the movement restricting portions 821 and 822. This is suitable for bringing the suction conveyor 2 closer to the uppermost one of the plurality of wafers Wf. Therefore, the uppermost wafer Wf is more easily sucked by the suction conveyor 2.

  If the suction conveyor 2 that slides the wafers Wf is used, the sucked wafers Wf can be smoothly retracted from directly above the stacked wafers Wf. At this time, there is little possibility that the plurality of wafers Wf are greatly disturbed.

  The plurality of wafers Wf are stacked so that the upper surface of the wafer Wf is parallel to the wafer suction surface 22c of the suction conveyor 2. For this reason, the suction force by the suction conveyor 2 acts substantially evenly on the entire surface of the uppermost wafer Wf that has floated due to the ejection of liquid from the nozzle 31. Such a configuration is suitable for accurately adsorbing the uppermost wafer Wf. Further, since the wafer suction surface 22c is inclined so that the front side in the sliding direction of the wafer Wf (the right side in the figure) is higher, it is suitable for efficiently transporting the wafer Wf in a short movement process.

  The nozzle 31 is arranged on the front side in the sliding direction of the wafer Wf with respect to the plurality of wafers Wf (right side in the figure), and ejects the liquid Lq toward the end surface Wfa of the stacked wafers Wf. That is, the liquid Lq is ejected from the nozzle 31 in the direction opposite to the sliding direction of the wafer Wf. Therefore, although the wafer Wf located at the uppermost position receives a force that moves forward in the sliding direction from the suction conveyor 2, the wafer Wf immediately below the wafer Wf located at the uppermost position is ejected from the nozzle 31. The liquid Lq receives a force in the direction opposite to the sliding direction. Thereby, it is possible to prevent the wafer Wf immediately below the wafer Wf positioned at the top from being erroneously carried.

  The liquid Lq in which the plurality of wafers Wf are immersed is heated by the heater 41 and is set to a temperature higher than room temperature. Since the liquid Lq has a property of decreasing in viscosity when heated, the liquid Lq is promoted to enter between adjacent wafers Wf. As a result, the wafer Wf positioned at the top of the plurality of wafers Wf can be easily separated from the wafer Wf adjacent immediately below the wafer Wf, and the top wafer Wf can be picked up appropriately.

  Of the compartments 231, 232, and 233, those that do not overlap with the suction section 22 a are sequentially shut off to the pump 26, so that the wafer Wf other than the wafer Wf to be sucked by a part other than the suction section 22 a is erroneously sucked. Can be prevented.

  A space 815 is formed in the mounting table 81. By configuring the mounting table 81 as described above, even when the number of the plurality of wafers Wf mounted on the mounting table 81 is reduced as shown in FIG. 14, the wafers Wf are more reliably disposed between the wafers Wf. A gap can be generated. As a result, the wafer Wf positioned below can be sucked and transported by the suction conveyor 2. As a result, the number of wafers Wf that remain mounted on the mounting table 81 without being sucked by the suction conveyor 2 can be reduced.

  In the above process, when the ejection of the liquid Lq from the nozzle 31 is continued without stopping the ejection of the liquid Lq from the nozzle 31 each time the wafer Wf is picked up, the wafer Wf positioned at the uppermost position is It can maintain a floating state. Therefore, it becomes unnecessary to lift the wafer Wf again after returning to the state where the wafer Wf is not lifted. As a result, the efficiency of the wafer transfer process can be improved.

  The wafer transfer method and the wafer transfer apparatus according to the present invention are not limited to the above-described embodiments. The specific configurations of the wafer transfer method and the wafer transfer apparatus according to the present invention can be varied in design in various ways.

A Wafer transfer device Lq Liquid Ls Liquid level Wf Wafer Wfa End surface 1 Wafer tank 2 Suction conveyor (wafer receiving means)
5 Relay Conveyor 6 Loading Conveyor 7 Stacker 11 Conveyor 12 Lifter 21 Roller 22 Endless Belt 22a Adsorption Section 22b Hole 22c Wafer Adsorption Surface 23 Vacuum Box 231, 232, 233 Compartment Chamber 23a Inlet 23b Hole 24 Hose 25 Dehydration Tank 26 Pump 27 Valve Unit 31 Nozzle (Liquid ejecting means)
311 nozzle (first liquid ejection means)
312 nozzle (second liquid ejection means)
313 nozzle (third liquid ejection means)
32 Sponge roller 41 Heater 42 Temperature sensor 43 Heater control unit 71 Pocket 81 Mounting base 811 Bottom base part 812, 813 Plate member 814 Auxiliary support member 815 Space 82 Support members 821 to 824 Movement restriction part

Claims (25)

A wafer transfer method for transferring a plurality of stacked wafers,
Injecting the liquid toward the end surfaces of the plurality of wafers in order to create a gap between any of the plurality of wafers located in the liquid;
Picking up at least the uppermost wafer of the plurality of wafers in a state where the gap is generated.   2. The wafer transfer method according to claim 1, wherein the step of ejecting the liquid includes a first step of ejecting the liquid toward the center of the end face in a direction in which the end face of the wafer extends.   The step of ejecting the liquid further includes a second step different from the first step, in which the liquid is ejected toward the end surface from a position overlapping the end surface in a direction in which the end surface of the wafer extends. Item 3. The wafer transfer method according to Item 2.   The wafer transfer method according to claim 3, wherein a direction in which the liquid is ejected in the first step and a direction in which the liquid is ejected in the second step are the same.   The wafer transfer method according to claim 3 or 4, wherein the liquid ejected in the first and second steps is ejected from the same position in the wafer stacking direction.   The step of ejecting the liquid further includes a third step of ejecting the liquid from the outside of the end surface in the direction in which the end surface of the wafer extends toward the end surface. Wafer transfer method.   The wafer transfer method according to claim 6, wherein in the third step, the liquid is ejected toward an upper side of the wafer positioned at the uppermost position.   The wafer transfer according to claim 6 or 7, wherein the liquid ejected in the first step is ejected from a position lower than a position from which the liquid is ejected in the third step in the wafer stacking direction. Method.   9. The wafer transfer method according to claim 1, wherein, in the step of ejecting the liquid, the liquid is ejected in a flat shape along the wafer stacking direction.   10. The wafer transfer method according to claim 1, wherein the step of ejecting the liquid is continuously performed before and after the step of picking up the wafer.   A step of conveying the wafer in order from the top wafer by suction slide means for sliding the wafer in the in-plane direction with the top wafer among the plurality of wafers being sucked; The wafer transfer method according to claim 1. The suction slide means includes a pair of rollers spaced apart from each other, and an endless belt wound around the pair of rollers,
The wafer transfer method according to claim 11, wherein the endless belt is provided with a plurality of holes connected to a space surrounded by the endless belt and capable of being depressurized.   The wafer transfer method according to claim 11 or 12, wherein, in the step of ejecting the liquid, the liquid is ejected from the front side in the sliding direction of the wafer to the plurality of wafers. A wafer transfer apparatus for transferring a plurality of stacked wafers,
At least one liquid ejecting means that creates a gap between the plurality of wafers by ejecting the liquid toward the end surfaces of the plurality of wafers located in the liquid;
And a wafer receiving means capable of receiving at least the uppermost wafer among the plurality of wafers in a state in which the gap is generated.   15. The wafer transfer apparatus according to claim 14, wherein the at least one liquid ejecting unit includes a first liquid ejecting unit that ejects the liquid toward a center of the end surface in a direction in which the end surface of the wafer extends.   The at least one liquid ejecting means is disposed at a position overlapping with the end face in the extending direction of the end face, and ejects the liquid toward the end face. The second liquid ejecting means is different from the first liquid ejecting means. The wafer transfer apparatus according to claim 15, further comprising:   The wafer transfer apparatus according to claim 16, wherein both the first and second liquid ejecting means eject the liquid in the same direction.   18. The wafer conveyance device according to claim 16, wherein the first liquid ejecting unit and the second liquid ejecting unit are located at the same position in the wafer stacking direction.   The at least one liquid ejecting means further includes third liquid ejecting means for ejecting the liquid from the outside of the end face toward the end face in the extending direction of the end face. Wafer transfer device.   20. The wafer transfer apparatus according to claim 19, wherein the third liquid ejecting unit further ejects the liquid toward an upper side of the uppermost wafer.   21. The wafer conveyance device according to claim 19, wherein the first liquid ejecting unit is positioned lower than the third liquid ejecting unit in the wafer stacking direction.   The wafer transfer apparatus according to any one of claims 14 to 21, wherein any one of the at least one liquid ejecting means ejects the liquid having a flat shape along a stacking direction of the wafers.   23. The wafer transfer according to claim 14, wherein the wafer receiving means includes suction slide means for sliding the wafer in an in-plane direction with the uppermost one of the plurality of wafers being sucked. apparatus. The suction slide means includes a pair of rollers spaced apart from each other, and an endless belt wound around the pair of rollers,
24. The wafer transfer apparatus according to claim 23, wherein the endless belt is provided with a plurality of holes connected to a space surrounded by the endless belt and capable of being depressurized.   25. The wafer transfer apparatus according to claim 23, wherein the at least one liquid ejecting unit is disposed on the front side in the sliding direction of the wafer with respect to the plurality of wafers.

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