JP5295720B2 - Semiconductor wafer processing equipment - Google Patents

Abstract

A semiconductor wafer processing device can shorten the time for conveying the wafer out and can prevent the damage of the semiconductor wafer in conveying the semiconductor wafer out. The semiconductor wafer processing device comprises the following components: a box for accommodating the semiconductor wafer; a box loading table for loading the box; and a conveying device for conveying the semiconductor wafer accommodated in the box in and out, wherein, the box is provided with an opening and a plurality of wafer accommodating parts. Each wafer accommodating part accommodates one semiconductor wafer with a mode that the surface and the back surface of the semiconductor wafer are in an approximately horizontal direction. The opening is opposite with the moving device which is used for conveying the semiconductor wafer in and out relatively to the box. The semiconductor wafer processing device furthermore comprises the following components: a camera device which is provided oppositely with the opening for performing image shooting on the plurality of wafer receiving parts of the box; a moving device for relatively moving the box loading table and the camera device in a vertical direction; a determining device which analyzes the image that is shot by the camera device for determining the accommodating state of the semiconductor wafer; and a storage device which stores the determination result determined by the determining device.

Description

  The present invention relates to a semiconductor wafer processing apparatus provided with a cassette for storing a semiconductor wafer.

  A semiconductor wafer in which devices such as IC and LSI are formed on a plurality of surfaces and each device is partitioned by a division line (street) is thinned to a predetermined thickness by grinding or polishing the back surface by a grinding device or a polishing device. After being divided, the dividing line is cut by a cutting device to be divided into individual devices. The divided devices are widely used in electric devices such as mobile phones and personal computers.

  In a processing apparatus such as a grinding apparatus, a polishing apparatus, or a cutting apparatus, a plurality of semiconductor wafers are accommodated in a cassette and supplied to the processing apparatus. The cassette is provided with a plurality of wafer accommodating portions for accommodating one semiconductor wafer, and the semiconductor wafers are accommodated in a stacked manner in the wafer accommodating portion so that the front and back surfaces thereof are directed in the horizontal direction.

  The semiconductor wafer accommodated in the cassette is unloaded from the opening of the cassette by the conveying means and subjected to predetermined processing, and is loaded into the same cassette or another cassette after the processing is completed.

  In the semiconductor wafer manufacturing process, the same cassette is used in a plurality of processes, and the semiconductor wafer is not necessarily accommodated in all wafer accommodating portions of the cassette placed on the processing apparatus.

For example, if the semiconductor wafer is damaged in the protective tape adhering process, dicing tape adhering process, etc., before the grinding process or cutting process, the grinding machine with the wafer containing part containing the damaged semiconductor wafer empty Or a processing device such as a cutting device.
JP 2006-21264 A JP 2003-311615 A JP 2003-229382 A

  Generally, the conveying means of a processing apparatus has an optical sensor for detecting the presence or absence of a semiconductor wafer accommodated in a cassette, and after the conveying means moves to each wafer accommodating portion for unloading the semiconductor wafer. Since the presence or absence of the wafer is confirmed by the optical sensor, there is a problem that the throughput is lowered when there is a wafer accommodating portion in which the semiconductor wafer is not accommodated.

  In addition, each wafer housing portion of many cassettes is formed of comb-shaped side walls facing each other so as to support only the outer peripheral portion of the semiconductor wafer. In the cassette having such a structure, when a semiconductor wafer is accommodated, the semiconductor wafer is easily inserted across the wafer accommodating portions of the left and right side walls which are different from each other.

  When the semiconductor wafer is accommodated across the wafer accommodating portions that are different on the left and right side walls, there is a problem in that the transport means and the semiconductor wafer collide with each other and the semiconductor wafer is damaged when the wafer is unloaded.

  Further, even when the semiconductor wafer is accommodated by protruding from the opening of the cassette, similarly, there is a problem that when the semiconductor wafer is unloaded, the transport means and the semiconductor wafer collide to damage the semiconductor wafer.

  The present invention has been made in view of the above points, and an object of the present invention is to reduce the semiconductor wafer carry-out time from the cassette and prevent the semiconductor wafer from being damaged when the semiconductor wafer is carried out. It is to provide a processing apparatus.

According to the present invention, there is provided a semiconductor wafer processing apparatus including a cassette for storing a semiconductor wafer, a cassette mounting table on which the cassette is mounted, and a transport unit for loading / unloading the semiconductor wafer stored in the cassette. The cassette includes a plurality of wafer storage portions in which a single semiconductor wafer is stored in a direction in which the front and back surfaces are substantially horizontal, and an opening facing the transport means for loading / unloading the semiconductor wafer into / from the cassette. And an image pickup means that is arranged to face the opening and picks up images of a plurality of wafer storage portions of the cassette, and a movement that moves the cassette mounting table and the image pickup means in a relatively vertical direction. means and a discriminating means for discriminating the accommodating state of the semiconductor wafer by analyzing the image captured by the image pickup means, storage means for storing a determination result of the determination in該判another means, the opening Disposed above or below the parts, the semiconductor wafer processing device, wherein, further comprising a reflecting mirror for projecting the imageable state imaging device of a semiconductor wafer housed projects from the opening Is provided.

  According to the present invention, the cassette mounting table and the imaging means are relatively moved in the vertical direction to image each wafer accommodating portion, and the presence / absence of the semiconductor wafer in each wafer accommodating portion is confirmed in advance by analyzing the captured image. Therefore, when the semiconductor wafer is carried out from the cassette, the carrying time can be shortened by positioning the carrying means only in the wafer containing portion in which the semiconductor wafer is accommodated.

  Further, even when the semiconductor wafer is accommodated across the steps in the wafer accommodating portions on the left and right side walls by analyzing the captured image, it becomes possible to detect the difference in accommodation of the semiconductor wafer before carrying out the wafer. It is possible to prevent damage to the semiconductor wafer due to interference with the conveying means.

  If a reflecting mirror is placed above or below the cassette opening, the presence or absence of the semiconductor wafer that is projected and received from the opening can be analyzed by taking an image projected on the reflecting mirror and analyzing it. It becomes possible to detect, and damage to the semiconductor wafer due to interference between the semiconductor wafer and the conveying means can be prevented.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a semiconductor wafer 11 before being processed to a predetermined thickness. The semiconductor wafer 11 shown in FIG. 1 is made of, for example, a silicon wafer having a thickness of 700 μm, and a plurality of streets 13 are formed in a lattice shape on the surface 11a, and a plurality of streets partitioned by the plurality of streets 13 are formed. A device 15 such as an IC or LSI is formed in the region.

  The semiconductor wafer 11 configured as described above includes a device region 17 in which the device 15 is formed, and an outer peripheral surplus region 19 that surrounds the device region 17. A notch 21 is formed on the outer periphery of the semiconductor wafer 11 as a mark indicating the crystal orientation of the silicon wafer.

  A protective tape 23 is attached to the surface 11a of the semiconductor wafer 11 by a protective tape attaching process. Therefore, when the semiconductor wafer 11 is ground, the front surface 11a of the semiconductor wafer 11 is protected by the protective tape 23, and the back surface 11b is exposed as shown in FIG.

  Hereinafter, a grinding apparatus 2 which is a kind of semiconductor wafer processing apparatus for grinding the back surface 11b of the semiconductor wafer 11 thus formed to a predetermined thickness will be described with reference to FIG. Reference numeral 4 denotes a housing of the grinding apparatus 2, and two columns 6 a 6 b are erected vertically at the rear of the housing 4.

  A pair of guide rails (only one is shown) 8 extending in the vertical direction is fixed to the column 6a. A rough grinding unit 10 is mounted along the pair of guide rails 8 so as to be movable in the vertical direction. The rough grinding unit 10 is attached to a moving base 12 whose housing 20 moves up and down along a pair of guide rails 8.

  The rough grinding unit 10 includes a housing 20, a spindle (not shown) rotatably accommodated in the housing 20, a servo motor 22 that rotationally drives the spindle, and a plurality of rough grinding grinding wheels fixed to the tip of the spindle. A grinding wheel 24 having 26 is included.

  The rough grinding unit 10 includes a rough grinding unit moving mechanism 18 including a ball screw 14 and a pulse motor 16 that move the rough grinding unit 10 up and down along a pair of guide rails 8. When the pulse motor 16 is pulse-driven, the ball screw 14 rotates and the moving base 12 is moved in the vertical direction.

  A pair of guide rails (only one is shown) 19 extending in the vertical direction is also fixed to the other column 6b. A finish grinding unit 28 is mounted along the pair of guide rails 19 so as to be movable in the vertical direction.

  The finish grinding unit 28 is attached to a moving base (not shown) in which the housing 36 moves in the vertical direction along the pair of guide rails 19. The finish grinding unit 28 includes a housing 36, a spindle (not shown) rotatably accommodated in the housing 36, a servo motor 38 that rotationally drives the spindle, and a grinding wheel 42 for finish grinding fixed to the tip of the spindle. A grinding wheel 40 is included.

  The finish grinding unit 28 includes a finish grinding unit moving mechanism 34 including a ball screw 30 and a pulse motor 32 that move the finish grinding unit 28 in the vertical direction along the pair of guide rails 19. When the pulse motor 32 is driven, the ball screw 30 rotates and the finish grinding unit 28 is moved in the vertical direction.

  The grinding device 2 includes a turntable 44 disposed so as to be substantially flush with the upper surface of the housing 4 on the front side of the columns 6a and 6b. The turntable 44 is formed in a relatively large-diameter disk shape, and is rotated in a direction indicated by an arrow 45 by a rotation drive mechanism (not shown).

  On the turntable 44, three chuck tables 46 are arranged so as to be rotatable in a horizontal plane, spaced from each other by 120 ° in the circumferential direction. The chuck table 46 has a suction chuck formed in a disk shape by a porous ceramic material, and sucks and holds the wafer placed on the holding surface of the suction chuck by operating a vacuum suction means.

  The three chuck tables 46 arranged on the turntable 44 are rotated in accordance with the turntable 44, so that the wafer loading / unloading area A, rough grinding area B, finish grinding area C, and wafer loading / unloading are performed. The region A is sequentially moved.

  The front portion of the housing 4 includes a first wafer cassette 50, a wafer transfer robot 54 having a link 51 and a hand 52, a positioning table 56 having a plurality of positioning pins 58, a wafer loading mechanism (loading arm) 60, A wafer unloading mechanism (unloading arm) 62, a spinner cleaning device 64 that cleans and spin-drys the ground wafer, and a second wafer cassette 66 that stores the ground wafer that has been cleaned and spin-dried by the spinner cleaning device 64. Is arranged.

  The spinner cleaning device 64 has a spinner table 68 that rotates while sucking and holding the ground semiconductor wafer. The spinner table 68 has a diameter that is approximately equal to or larger than the diameter of the semiconductor wafer. The spinner cleaning device 64 has a cleaning water supply nozzle (not shown) that supplies cleaning water toward the ground wafer that is adsorbed and held on the spinner table 68.

  As shown in FIG. 4, a plurality of wafer accommodating portions 70 formed in a comb shape are formed on both side walls 50 a and 50 b of the first wafer cassette 50. The first wafer cassette 50 has an opening 72 that faces the wafer transfer robot 54, and the semiconductor wafer 11 is carried into the first wafer cassette 50 through the opening 72, and from the first wafer cassette 50. It is carried out.

  The semiconductor wafer 11 is accommodated in the first wafer cassette 50 by inserting both sides thereof into a wafer accommodating portion 70 formed on the side walls 50a, 50b of the first wafer cassette 50. Reference numeral 73 denotes a handle that is gripped when the first wafer cassette 50 is conveyed. The second wafer cassette 66 has the same configuration as the first wafer cassette 50.

  Referring to FIG. 1 and FIG. 5 together, a camera 55 as an imaging unit is mounted on the wafer transfer robot 54. The wafer transfer robot 54 is configured to be movable in three axial directions, ie, the X-axis direction, the Y-axis direction, and the Z-axis direction, and the first wafer cassette 50 in which a plurality of semiconductor wafers 11 are accommodated is a housing as a cassette mounting table. 4, the wafer transport robot 50 moves in the vertical direction, and the camera 55 images all the semiconductor wafers 11 accommodated in the first wafer cassette 50.

  The captured image captured by the camera 55 is sent to the determination unit 76 of the controller 74, and the determination unit 76 analyzes the captured image to determine the accommodation state of the semiconductor wafer 11. The determination result determined by the determination means 76 is stored in a storage means 78 such as a RAM. The accommodation state discriminated by the discriminating means 76 can discriminate not only the presence / absence of the semiconductor wafer and the step shift but also the warpage of the semiconductor wafer 11.

  For example, if the determination means 76 determines that the semiconductor wafer 11 is not stored in the nth wafer storage section 70 from above, the result is stored in the storage means 78, and the wafer transfer robot 54 moves the hand 52 from above. Since the control is performed so as to access the wafer storage unit 70 in the next stage without accessing the n-th wafer storage unit 70, the wafer transfer time by the wafer transfer robot 54 can be shortened.

  Further, when it is determined that the semiconductor wafer 11 is accommodated across the wafer accommodating portions 70 of the left and right side walls 50a and 50b, the controller 74 controls the state so as to issue an alarm with an alarm device or the like. By doing so, it is also possible to notify the operator and correct the accommodation state of the semiconductor wafer 11 by the operator.

  Furthermore, in the grinding device 2 of the present embodiment, a reflector inclined at 45 degrees is provided below the opening 72 so as to project the semiconductor wafer 11 accommodated by protruding from the opening 72 so that the semiconductor wafer 11 can be captured by the camera 55. Yes.

  By capturing an image projected on the reflecting mirror 80 and analyzing it by the discriminating means 76, it is possible to detect the presence or absence of the semiconductor wafer 11 that is projected and accommodated from the opening 72 before being carried out. It is possible to prevent damage to the semiconductor wafer 11 due to interference with the transfer robot 54.

  The arrangement position of the reflecting mirror 80 is not limited to the position below the opening 72 shown in FIG. 5, but the reflecting mirror 80 is arranged above the opening 72 as in the embodiment shown in FIG. May be. In this case, the same effect as that of the embodiment shown in FIG. 5 can be obtained.

  Further, the reflecting mirror is not limited to the 45 ° tilted reflecting mirror shown in FIG. 5, and a hemispherical mirror or the like can be similarly applied. Further, in FIG. 5, the reflecting mirror is disposed on the mounting portion of the wafer cassette 50, but a mirror may be disposed on the wafer cassette 50 itself.

  Referring to FIG. 7, an external perspective view of a grinding apparatus 2A according to the second embodiment of the present invention is shown. In the description of this embodiment, the same components as those of the first embodiment shown in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted to avoid duplication.

  In the grinding apparatus 2 </ b> A of the present embodiment, a column 82 is erected facing the opening 72 of the first wafer cassette 50 at a position that does not interfere with the wafer transfer robot 54. A camera 55 is attached to the column 82 so that the camera 55 can be moved in the vertical direction by a vertical movement mechanism 84 composed of a ball screw and a pulse motor.

  Even in the grinding device 2A of the present embodiment, the same effect as that of the grinding device 2 of the first embodiment described above can be obtained by imaging the semiconductor wafer 11 accommodated in the first wafer cassette 50 by the camera 55. .

  In the above description, an example in which the present invention is applied to a grinding apparatus has been described. However, the present invention is not limited to this, and a cutting apparatus (dicing apparatus) for processing a semiconductor wafer similarly housed in a wafer cassette. It can be similarly applied to a polishing apparatus or the like.

It is a surface side perspective view of a semiconductor wafer. It is a back surface side perspective view of the semiconductor wafer where the protective tape was stuck. 1 is an external perspective view of a grinding apparatus according to a first embodiment of the present invention. It is a perspective view of the wafer cassette which accommodated the semiconductor wafer. It is explanatory drawing which shows the principal part of this invention. It is explanatory drawing which shows the modification of embodiment shown in FIG. It is an external appearance perspective view of the grinding device concerning a 2nd embodiment of the present invention.

Explanation of symbols

2,2A Grinding device 10 Coarse grinding unit 11 Semiconductor wafer 13 Street 15 Device 28 Finish grinding unit 44 Turntable 50 First wafer cassette 54 Wafer transfer robot 55 Camera 70 Wafer accommodating portion 82 Column 84 Vertical movement mechanism

Claims (2)

A semiconductor wafer processing apparatus comprising a cassette for storing a semiconductor wafer, a cassette mounting table on which the cassette is mounted, and a transport means for loading / unloading the semiconductor wafer stored in the cassette,
The cassette includes a plurality of wafer accommodating portions in which one semiconductor wafer is accommodated in a direction in which the front and back surfaces are substantially horizontal, and an opening facing the conveying means for carrying the semiconductor wafer into and out of the cassette. Have
An imaging means arranged to face the opening and imaging a plurality of wafer accommodating portions of the cassette;
Moving means for relatively moving the cassette mounting table and the imaging means in a vertical direction;
A discriminating means for analyzing a captured image captured by the imaging means and discriminating an accommodation state of the semiconductor wafer;
Storage means for storing the determination result determined by the determination means;
A reflector that is disposed above or below the opening and projects the semiconductor wafer that protrudes from the opening and is imaged by the imaging unit;
A semiconductor wafer processing apparatus, further comprising:   The semiconductor wafer processing apparatus according to claim 1, wherein the imaging unit is mounted on the transfer unit.

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