JP2013069886A - Method for grinding wafer and protective film forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for grinding a wafer capable of securing grinding accuracy and reliably removing a grinding dust attached during grinding without damaging a ground wafer.SOLUTION: A method for grinding a ground surface of a wafer comprises the steps of: forming a protective film on a support surface on the side opposite to the ground surface of the wafer by solidifying the support surface by coating the surface with a fluid resin; uniformizing the thickness of the protective film formed on the support surface on the side opposite to the ground surface of the wafer by turning a surface of the protective film; and holding a protective film side of a uniform thickness formed on the support surface on the side opposite to the ground surface of the wafer in a chuck table of a grinding device and grinding the ground surface of the wafer by grinding means.

Description

  The present invention relates to a grinding method for grinding a wafer such as a semiconductor wafer to a predetermined thickness.

  In the semiconductor device manufacturing process, a large number of rectangular areas are defined by dividing lines called streets arranged in a lattice pattern on the surface of a semiconductor wafer having a substantially disk shape, and ICs, LSIs, etc. are divided into the rectangular areas. Form the device. Individual devices are formed by dividing the semiconductor wafer on which a large number of devices are formed in this manner along the streets. In order to reduce the size and weight of the device, the semiconductor wafer is usually ground to the predetermined thickness by grinding the backside of the semiconductor wafer before it is cut along the street and divided into individual devices. .

  A grinding apparatus for grinding a back surface of a semiconductor wafer includes a chuck table having a holding surface for holding a workpiece, a grinding means for grinding a workpiece held on the chuck table, and a workpiece ground by the grinding means. Cleaning means for cleaning the object. When grinding the surface to be ground which is the back surface of the wafer with such a grinding apparatus, the supporting surface opposite to the surface to be ground (the surface in the normal wafer, one of the wafers for the substrate on the surface of the wafer) In the case of a so-called SOI wafer with bonded surfaces, a protective tape is attached to the other surface of the substrate wafer), and the surface to be ground is ground by holding this protective tape side on a chuck table. (For example, refer to Patent Document 1.)

  However, a protective tape is attached to the support surface opposite to the surface to be ground of the wafer, the surface to be ground is ground by holding this protective tape side on a chuck table, and then the protective tape is placed on the opposite side of the surface to be ground. When peeling from the support surface, the thinned wafer may be damaged. In addition, the ground wafer is cleaned by the cleaning means, but the grinding debris that has come around the contact surface between the protective tape and the chuck table is firmly attached to the protective tape and can be removed even if it is cleaned by the cleaning means. There is a problem that the cassette for storing the wafer after grinding cannot be contaminated and becomes a contamination source in a subsequent process.

  In order to solve the above-mentioned problems, a protective film is formed by coating a support surface opposite to the surface to be ground of the wafer with a liquid resin, and the surface of the wafer to be ground is held on the chuck table. A method for grinding a wafer in which the material is ground by a grinding means is disclosed in Patent Document 2 below.

JP 2004-319829 A Japanese Patent Laid-Open No. 2011-3611

  Thus, the protective film in which the support surface opposite to the surface to be ground of the wafer is coated with liquid resin has a thickness variation of several μm and air bubbles are mixed in, and reliability of grinding accuracy cannot be ensured. There is a risk of damaging the wafer.

  The present invention has been made in view of the above-mentioned facts, and the main technical problems thereof are to ensure grinding accuracy, not to damage the wafer after grinding, and to reliably remove grinding dust adhering during grinding. It is an object of the present invention to provide a method for grinding a wafer.

In order to solve the above main technical problem, according to the present invention, a wafer grinding method for grinding a surface to be ground of a wafer,
A protective film forming step of forming a protective film on the support surface by coating and solidifying a liquid resin on the support surface opposite to the surface to be ground of the wafer;
A protective film flattening step for turning the surface of the protective film formed on the support surface opposite to the surface to be ground of the wafer to make the thickness of the protective film uniform;
A grinding step in which a protective film side formed on a support surface opposite to the surface to be ground of the wafer is held on a chuck table of a grinding device and the surface to be ground of the wafer is ground by a grinding means.
A method for grinding a wafer is provided.

  In the present invention, a protective film forming step of forming a protective film on the support surface by coating and solidifying a liquid resin on the support surface opposite to the surface to be ground of the wafer is performed, and the surface of the protective film is turned. After carrying out the protective film flattening process to make the protective film uniform thickness, the protective film side with uniform thickness is held on the chuck table of the grinding device, and the grinding process is performed to grind the surface to be ground of the wafer by the grinding means Therefore, since the protective film placed on the chuck table of the grinding apparatus has a uniform thickness, the reliability of the grinding accuracy can be ensured and there is no possibility of damaging the wafer.

The perspective view of the wafer processed with the grinding method of the wafer by this invention. The perspective view of the protective film formation apparatus for implementing the protective film formation process and protective film planarization process in the grinding method of the wafer by this invention. The perspective view of the turning unit with which the protective film formation apparatus shown in FIG. 2 is equipped. The perspective view which shows the chuck table mechanism and chuck table moving mechanism with which the protective film formation apparatus shown in FIG. 2 is equipped. Explanatory drawing of the protective film formation process in the grinding method of the wafer by this invention. Explanatory drawing of the protective film planarization process in the grinding method of the wafer by this invention. Sectional drawing of the wafer in which the protective film planarization process shown in FIG. 6 was implemented. 1 is a perspective view of a grinding apparatus for performing a grinding step in a wafer grinding method according to the present invention. Explanatory drawing of the grinding process implemented using the grinding apparatus shown in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a wafer grinding method according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a wafer to be ground by the wafer grinding method according to the present invention. The wafer 10 shown in FIG. 1 is made of, for example, a silicon wafer having a thickness of 700 μm, and a plurality of streets 101 are arranged in a lattice pattern on the surface 10a, and ICs are formed in a plurality of regions partitioned by the plurality of streets 101. A device 102 such as an LSI is formed. The wafer 10 thus formed is formed to have a predetermined thickness (for example, 100 μm) by grinding the back surface 10b. Accordingly, the back surface 10b of the wafer 10 is a surface to be ground, and the surface 10a opposite to the surface to be ground is a support surface.

  In order to grind the back surface 10b of the wafer 10 to a predetermined thickness, the support surface (front surface 10a) opposite to the surface to be ground (back surface 10b) of the wafer 10 is coated with a liquid resin and solidified. The protective film forming step of forming a protective film on the surface of the wafer 10 and the surface of the protective film formed on the support surface (front surface 10a) opposite to the surface to be ground (back surface 10b) of the wafer 10 are turned to make the thickness of the protective film uniform. A protective film flattening step is performed. The protective film forming step and the protective film flattening step are performed using the protective film forming apparatus shown in FIG.

  The protective film forming apparatus 1 shown in FIG. 2 includes an apparatus housing generally indicated by numeral 2. The apparatus housing 2 has a rectangular parallelepiped main portion 21 that extends elongated and an upright wall 22 that is provided at a rear end portion (upper right end in FIG. 2) of the main portion 21 and extends upward. A pair of guide rails 221 and 221 extending in the vertical direction are provided on the front surface of the upright wall 22. A turning unit 3 as a turning means is mounted on the pair of guide rails 221 and 221 so as to be movable in the vertical direction.

  The turning unit 3 includes a moving base 31 and a spindle unit 32 attached to the moving base 31. The movable base 31 is provided with a pair of legs 311 and 311 extending in the vertical direction on both sides of the rear surface. The pair of legs 311 and 311 is slidably engaged with the pair of guide rails 221 and 221. Guided grooves 312 and 312 are formed. A support member 313 is mounted on the front surface of the movable base 31 slidably mounted on the pair of guide rails 221 and 221 provided on the upright wall 22, and the spindle unit 32 is attached to the support member 313. It is done.

  The spindle unit 32 includes a spindle housing 321 mounted on a support member 313, a rotating spindle 322 rotatably disposed on the spindle housing 321, and a servo motor as a drive source for rotationally driving the rotating spindle 322. 323. The lower end of the rotary spindle 322 protrudes downward beyond the lower end of the spindle housing 321, and a disk-shaped tool tool mounting member 324 is provided at the lower end. The tool tool 33 is detachably mounted on the tool tool mounting member 324.

Here, the attachment / detachment structure of the cutting tool 33 to the cutting tool mounting member 324 will be described with reference to FIG.
The tool tool mounting member 324 is provided with a tool mounting hole 324a penetrating in a vertical direction in a part of the outer peripheral portion eccentric from the rotation axis, and the tool mounting is performed from the outer peripheral surface corresponding to the tool mounting hole 324a. A female screw hole 324b reaching the hole 324a is provided. The bite tool 33 is inserted into the bite mounting hole 324a of the bite tool mounting member 324 thus configured, and the bolt 35 is screwed into the female screw hole 324b and tightened to tighten the bite tool 33. Removably attached to the. In the illustrated embodiment, the cutting tool 33 is formed of a cutting tool body 331 having a rectangular cross section formed of tool steel such as cemented carbide, and diamond or the like provided at the tip of the cutting tool body 331. What was comprised with the made cutting blade 332 is used. The tool tool 33 configured as described above and mounted on the tool tool mounting member 324 rotates in a plane parallel to a holding surface for holding a workpiece of a chuck table, which will be described later, by rotating the rotary spindle 322. I'm damned.

  Referring back to FIG. 2, the protective film forming apparatus 1 in the illustrated embodiment moves the turning unit 3 in the vertical direction along the pair of guide rails 221 and 221 (perpendicular to a holding surface of a chuck table described later). A turning unit feed mechanism 4 that can be moved in any direction. The turning unit feed mechanism 4 includes a male screw rod 41 disposed on the front side of the upright wall 22 and extending in the vertical direction. The male screw rod 41 is rotatably supported by bearing members 42 and 43 whose upper end and lower end are attached to the upright wall 22. The upper bearing member 42 is provided with a pulse motor 44 as a drive source for rotationally driving the male screw rod 41, and an output shaft of the pulse motor 44 is connected to the male screw rod 41 by transmission. A connecting portion (not shown) that protrudes rearward from the central portion in the width direction is also formed on the rear surface of the movable base 31, and a through female screw hole extending in the vertical direction is formed in the connecting portion. The male screw rod 41 is screwed into the female screw hole. Accordingly, when the pulse motor 44 is rotated forward, the moving base 31 and the turning unit 3 mounted on the moving base 31 are lowered or advanced, and when the pulse motor 44 is rotated reversely, the moving base 31 and the moving base 31 are mounted. The turned unit 3 is raised or retracted.

  2 and FIG. 4, the description will be continued with reference to FIG. 2 and FIG. 4, a substantially rectangular processing work portion 211 is formed on the rear half of the main portion 21 of the housing 2. 5 is disposed. As shown in FIG. 4, the chuck table mechanism 5 includes a support base 51 and a chuck table 52 disposed on the support base 51. The support base 51 slides on a pair of guide rails 23 and 23 extending in the direction indicated by the arrows 23a and 23b in the front-rear direction (the direction perpendicular to the front surface of the upright wall 22) on the processing work unit 211. The workpiece loading / unloading area 24 shown in FIG. 2 (position shown by a solid line in FIG. 4) and the bite tool 33 constituting the spindle unit 32 are opposed to each other by a chuck table moving mechanism 56 described later. And the machining area 25 (the position indicated by the two-dot chain line in FIG. 4).

  The chuck table 52 includes a chuck table main body 521 formed in a cylindrical shape by a metal material such as stainless steel, and an adsorption chuck 522 disposed on the upper surface of the chuck table main body 521. The suction chuck 522 is made of an appropriate porous material such as porous ceramics, and communicates with suction means (not shown). Therefore, by selectively communicating the suction chuck 522 to a suction means (not shown), the workpiece placed on the holding surface which is the upper surface is sucked and held. The illustrated chuck table mechanism 5 includes a cover member 54 that has a hole through which the chuck table 52 is inserted, covers the support base 51 and the like, and is movably disposed together with the support base 51.

  4, the protective film forming apparatus 1 in the illustrated embodiment moves the chuck table that moves the chuck table mechanism 5 along the pair of guide rails 23 in the directions indicated by the arrows 23a and 23b. A mechanism 56 is provided. The chuck table moving mechanism 56 includes a male screw rod 561 disposed between the pair of guide rails 23 and 23 and extending in parallel with the guide rails 23 and 23, and a servo motor 562 that rotationally drives the male screw rod 561. The male screw rod 561 is screwed into a screw hole 511 provided in the support base 51, and its tip is rotatably supported by a bearing member 563 attached by connecting a pair of guide rails 23, 23. ing. The servo motor 562 has a drive shaft connected to the base end of the male screw rod 561 by transmission. Accordingly, when the servo motor 562 rotates in the forward direction, the support base 51, that is, the chuck table mechanism 5, moves in the direction indicated by the arrow 23a. When the servo motor 562 rotates in the reverse direction, the support base 51, that is, the chuck table mechanism 5, moves in the direction indicated by the arrow 23b. It can be moved. Thus, the chuck table mechanism 5 moved in the directions indicated by the arrows 23a and 23b is selectively positioned in the workpiece loading / unloading area indicated by the solid line and the machining area indicated by the two-dot chain line in FIG. Further, the chuck table moving mechanism 56 is reciprocated in the direction indicated by the arrows 23a and 23b over a predetermined range in the processing region, that is, in parallel with the holding surface which is the upper surface of the suction chuck 522.

  Returning to FIG. 2, the description continues and the cross-sectional shape is a reverse channel shape on both sides of the moving direction of the cover member 54 constituting the chuck table mechanism 5, and the pair of guide rails 23, 23 and the male screw rod Bellows means 57 and 58 are attached to cover 561, servo motor 562 and the like. The bellows means 57 and 58 can be formed from any suitable material such as campus cloth. The front end of the bellows means 57 is fixed to the front wall of the processing unit 211, and the rear end is fixed to the front end surface of the cover member 54 of the chuck table mechanism 5. The front end of the bellows means 58 is fixed to the rear end surface of the cover member 54 of the chuck table mechanism 5, and the rear end is fixed to the front surface of the upright wall 22 of the apparatus housing 2. When the chuck table mechanism 5 is moved in the direction indicated by the arrow 23a, the bellows means 57 is expanded and the bellows means 58 is contracted, and when the chuck table mechanism 5 is moved in the direction indicated by the arrow 23b, the bellows means. 57 is contracted and the bellows means 58 is extended.

  Continuing the description with reference to the drawings, on the front half of the main portion 21 of the apparatus housing 2, a cassette placement area 11a, a workpiece temporary placement area 12a, and a cleaning area 13a are provided. The cassette 11 that accommodates the wafer 10 shown in FIG. 1 before processing is placed in the cassette placement region 11a. The workpiece temporary placement area 12a is provided with a workpiece temporary placement means 12 for temporarily placing the unprocessed wafer unloaded from the cassette 11 placed in the cassette placement area 11a. The cleaning area 13a is provided with cleaning means 13 for cleaning the processed workpiece.

  A workpiece conveying means 14 is disposed between the cassette placing area 11a and the workpiece temporary placing area 12a. The workpiece conveying means 14 is placed in the cassette placing area 11a. The unprocessed wafer stored in the cassette 11 is carried out to the workpiece temporary placement means 12, and the processed wafer cleaned by the cleaning means 13 is transferred to the cassette 11 placed in the cassette placement region 11a. To do. A workpiece loading means 15 is disposed between the workpiece temporary storage area 12a and the workpiece loading / unloading area 24. The workpiece loading means 15 is a workpiece loading means 15. The unprocessed wafer placed on the temporary placing means 12 is transported onto the chuck table 52 of the chuck table mechanism 5 positioned in the workpiece loading / unloading area 24. A workpiece unloading means 16 is disposed between the workpiece loading / unloading area 24 and the cleaning section 13a. The workpiece unloading means 16 is positioned in the workpiece loading / unloading area 24. The processed wafer placed on the chuck table 52 is transferred to the cleaning means 13.

  Further, the protective film forming apparatus 1 in the illustrated embodiment forms a protective film on a support surface opposite to the ground surface of the wafer which is a workpiece and is disposed adjacent to the main portion 21 of the apparatus housing 2. A protective film forming means 6 is provided. The protective film forming means 6 includes a spinner table 61 that holds a wafer that is a workpiece, an electric motor 62 that rotationally drives the spinner table 61, and a support for the wafer that is a workpiece held on the spinner table 61. A liquid resin supply nozzle 63 for supplying a liquid resin to the surface and a protective film solidifying device 64 for solidifying a resin protective film formed on a support surface of a wafer as a workpiece. Similar to the chuck table 52, the spinner table 61 includes a chuck table main body and an adsorption chuck 522 made of an appropriate porous material such as porous ceramics disposed on the upper surface of the chuck table main body. A workpiece placed on the upper surface (holding surface) of the holding chuck is sucked and held by operating a suction means (not shown). The liquid resin supply nozzle 63 is connected to liquid resin supply means (not shown). The protective film solidifier 64 is selected depending on the liquid resin supplied from the liquid resin supply nozzle 63, but a heater or an ultraviolet irradiator can be used.

The protective film forming apparatus 1 in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
In order to perform the protective film forming step and the protective film flattening step by the protective film forming apparatus 1 described above, the cassette 11 in which the wafer 10 before processing is placed is placed on the cassette placement region 11a, and the processing start switch ( When the workpiece conveying means 14 is activated, the back surface 10b of the unprocessed wafer 10 accommodated in a predetermined position of the cassette 11 placed in the cassette placement region 11a is handed. 141 sucked and held, and carried out of the cassette 11 and placed on the spinner table 61 of the protective film forming means 6 on the back surface 10b side of the wafer 10. Then, the wafer 10 is sucked and held on the spinner table 61 by operating a suction means (not shown). Accordingly, the wafer 10 held on the spinner table 61 has a surface 10a on the upper side as shown in FIG. If the wafer 10 is sucked and held on the spinner table 61 in this way, the outlet 63a of the liquid resin supply nozzle 63 is centered on the spinner table 61 as shown in FIG. The liquid resin supply means (not shown) is operated, and a predetermined amount of a liquid resin 60 such as a resist film that is dissolved by a cleaning liquid made of sulfuric acid and hydrogen peroxide is dropped from the jet outlet 63a of the liquid resin supply nozzle 63. . As the liquid resin 60, a resin that is solidified when heated or irradiated with ultraviolet rays is used. The dropping amount of the liquid resin 60 is set so that the thickness of the protective film formed on the surface 10a of the wafer 10 is 10 to 30 μm. When the liquid resin 60 is dropped in this way, the liquid resin supply nozzle 63 is positioned at the standby position shown in FIG. Next, the spinner table 61 is rotated in a direction indicated by an arrow G in FIG. 5A at a rotational speed of 300 to 1000 rpm for a predetermined time (for example, 1 minute). As a result, as shown in FIG. 5B, the liquid resin 60 dropped on the central region of the surface 10a of the wafer 10 flows to the outer peripheral portion by centrifugal force to cover the surface 10a of the wafer 10, and the protective film 600 Form. When the protective film 600 is formed on the surface 10a of the wafer 10 in this way, the protective film solidifying device 64 composed of a heater or an ultraviolet irradiator is operated as shown in FIG. Solidify (protective film forming step). The protective film 600 that covers the surface 10a that becomes the support surface when the back surface of the wafer 10 is ground has an average thickness of about 30 μm, but is not uniform, as shown in FIG. 5C. Is thinner and thicker towards the outer periphery.

  When the protective film forming step is performed as described above, the suction holding of the wafer 10 by the spinner table 61 is released. Next, the workpiece conveying means 14 is operated to convey the wafer 10 that has been subjected to the protective film forming step placed on the spinner table 61 to the workpiece temporary placing means 12. Therefore, the wafer 10 conveyed to the workpiece temporary placing means 12 has the protective film 600 coated on the surface 10a as the support surface on the upper side. Then, the workpiece temporary placing means 12 performs centering of the conveyed wafer 10 before processing. Next, the workpiece carry-in means 15 is operated so that the unprocessed wafer 10 centered by the workpiece temporary placement means 12 is positioned in the workpiece carry-in / out area 24. It is placed on the chuck table 52. The semiconductor wafer 10 placed on the chuck table 52 is sucked and held on the chuck table 52 by suction means (not shown). The wafer 10 sucked and held on the chuck table 52 in this way has the protective film 600 coated on the surface 10a on the upper side.

  If the wafer 10 is sucked and held on the chuck table 52, the chuck table moving mechanism 56 (see FIG. 4) is operated to move the chuck table mechanism 5 in the direction indicated by the arrow 23a, thereby holding the wafer 10 in the chuck table 52. Is positioned in the machining area 25. When the chuck table 52 holding the wafer 10 is positioned in the processing region 25 in this way, the surface of the protective film 600 formed on the surface 10a of the wafer 10 is turned to make the thickness of the protective film 600 uniform. A protective film flattening step is performed.

  First, the rotary spindle 322 is driven to rotate, and the tool tool mounting member 324 to which the tool tool 33 is attached is rotated in the direction indicated by the arrow 33a in FIG. 6 at a rotational speed of, for example, 6000 rpm. Then, the turning unit 3 is lowered to position the cutting tool 33 at a predetermined cutting position. Next, for example, when the turning width of the cutting edge 332 of the cutting tool 33 is 20 or more μm, the chuck table 52 holding the wafer 10 is moved to the right as shown by the arrow 23a from the position shown by the solid line in FIG. Move at a feed rate of 2 mm / sec. As a result, the surface (upper surface) of the protective film 600 formed on the surface 10 a of the wafer 10 by the cutting edge 332 of the cutting tool 33 that rotates in a plane parallel to the holding surface of the chuck table 52 as the rotary spindle 322 rotates. ) Is turned (protective film flattening step). As a result, the protective film 600 is formed with a uniform thickness as shown in FIG.

  As described above, when the protective film flattening step is completed, the turning unit 3 is raised and the rotation of the chuck table 52 is stopped. Next, the chuck table 52 is moved in the direction indicated by the arrow 23b in FIG. 2 to be positioned in the workpiece loading / unloading area 24, and the wafer 10 that has been subjected to the protective film flattening process on the chuck table 52 is sucked and held. To release. Then, the wafer 10 whose suction holding is released is carried out by the workpiece carrying-out means 16 and conveyed to the cleaning means 13. The wafer 10 conveyed to the cleaning means 13 is cleaned and spin-dried here. The wafer 10 cleaned and spin-dried by the cleaning unit 13 is stored in a predetermined position of the cassette 11 by the workpiece transfer unit 14.

  The wafer 10 on which the above-described protective film flattening step is performed is conveyed to a grinding apparatus. The protective film side formed on the support surface (front surface 10a) opposite to the surface to be ground (back surface 10b) of the wafer 10 is held on the chuck table of the grinding apparatus, and the surface to be ground (back surface) of the wafer 10 is retained. 10b) is ground by a grinding means. In the illustrated embodiment, this grinding step is performed using a grinding apparatus 8 shown in FIG. A grinding apparatus 8 shown in FIG. 8 includes a chuck table 81 that holds a workpiece, and a grinding means 82 that grinds the workpiece held on the chuck table 81. The chuck table 81 sucks and holds the workpiece on the upper surface and is rotated in the direction indicated by the arrow 81a in FIG. The grinding means 82 includes a spindle housing 821, a rotating spindle 822 that is rotatably supported by the spindle housing 821 and rotated by a rotation driving mechanism (not shown), a mounter 823 attached to the lower end of the rotating spindle 822, and the mounter And a grinding wheel 824 attached to the lower surface of 823. The grinding wheel 824 includes an annular base 825 and a grinding wheel 826 that is annularly attached to the lower surface of the base 825, and the base 825 is attached to the lower surface of the mounter 823 by fastening bolts 827. ing.

  In order to carry out the grinding step of grinding the surface to be ground (back surface 10b) of the wafer 10 using the grinding apparatus 8 described above, the wafer 10 is supported on the upper surface (holding surface) of the chuck table 81 as shown in FIG. The protective film 600 side formed on the surface (surface 10a) is placed. Then, the wafer 10 is sucked and held on the chuck table 81 by operating a suction means (not shown). Accordingly, the wafer 10 sucked and held on the chuck table 81 has the surface to be ground (back surface 10b) on the upper side. If the wafer 10 is sucked and held on the chuck table 81 in this way, the grinding wheel 824 of the grinding means 82 is moved to the arrow 824a in FIG. 8 while the chuck table 81 is rotated in the direction indicated by the arrow 81a in FIG. 9 is rotated at, for example, 6000 rpm, and the grinding surface (lower surface) of the grinding wheel 826 is brought into contact with the surface to be ground (back surface 10b) as shown in FIG. 9, and the grinding wheel 824 is moved to an arrow 824b in FIGS. As shown in Fig. 5, the workpiece is ground by 600 μm, for example, downward (in a direction perpendicular to the holding surface of the chuck table 81) at a predetermined grinding feed rate. As a result, in the illustrated embodiment, the wafer 10 is formed to a thickness of 100 μm. In the grinding step, the protective film 600 side formed on the support surface (surface 10a) of the wafer 10 is placed on the upper surface (holding surface) of the chuck table 81. The protective film 600 is the above-described protective film flattening step. Since the thickness is uniformly formed by performing the above, the reliability of the grinding accuracy can be ensured and the wafer is not damaged.

  The wafer 10 that has been subjected to the above-described grinding process and formed to a predetermined thickness is transported to a protective film removing device that removes the protective film 600 formed on the support surface (surface 10a), and the protective film removing device removes the protective film. The process is performed and the protective film 600 is removed. In the illustrated embodiment, the protective film 600 is coated with a liquid resin 60 for a resist film that is dissolved by a cleaning liquid composed of sulfuric acid and hydrogen peroxide solution, and is solidified by irradiation with ultraviolet rays. It can melt | dissolve with the washing | cleaning liquid consisting of.

1: Protective film forming device 2: Device housing 3: Turning unit 31: Moving base 32: Spindle unit 321: Spindle housing 322: Rotating spindle 323: Servo motor 324: Tool tool mounting member 33: Tool tool 331: Tool body 332 : Cutting blade 4: Turning unit feed mechanism 5: Chuck table mechanism 51: Support base 52: Chuck table 56: Chuck table moving mechanism 6: Protective film forming means 61: Spinner table 63: Liquid resin supply nozzle 64: Protective film solidification 8: Grinding device 81: Chuck table 82: Grinding means 824: Grinding wheel 10: Wafer 600: Protective film

When the protective film flattening step as described above is finished, Ru raised turning unit 3. Next, the chuck table 52 is moved in the direction indicated by the arrow 23b in FIG. 2 to be positioned in the workpiece loading / unloading area 24, and the wafer 10 that has been subjected to the protective film flattening process on the chuck table 52 is sucked and held. To release. Then, the wafer 10 whose suction holding is released is carried out by the workpiece carrying-out means 16 and conveyed to the cleaning means 13. The wafer 10 conveyed to the cleaning means 13 is cleaned and spin-dried here. The wafer 10 cleaned and spin-dried by the cleaning unit 13 is stored in a predetermined position of the cassette 11 by the workpiece transfer unit 14.

The present invention relates to a grinding method and a protective film forming apparatus for grinding a wafer such as a semiconductor wafer to a predetermined thickness.

The present invention has been made in view of the above-mentioned facts, and the main technical problems thereof are to ensure grinding accuracy, not to damage the wafer after grinding, and to reliably remove grinding dust adhering during grinding. It is an object to provide a method for grinding a wafer and a protective film forming apparatus .

In order to solve the above main technical problem, according to the present invention, a wafer grinding method for grinding a surface to be ground of a wafer,
A protective film forming step of forming a protective film on the support surface by coating and solidifying a liquid resin on the support surface opposite to the surface to be ground of the wafer;
A protective film flattening step for turning the surface of the protective film formed on the support surface opposite to the surface to be ground of the wafer to make the thickness of the protective film uniform;
A grinding step in which a protective film side formed on a support surface opposite to the surface to be ground of the wafer is held on a chuck table of a grinding device and the surface to be ground of the wafer is ground by a grinding means.
A method for grinding a wafer is provided.
Further, in the present invention, a protective film forming apparatus for forming a protective film on a support surface of a wafer,
A cassette placement area for placing the cassette containing the wafer, a workpiece transport means for unloading the wafer from the cassette placed in the cassette placement area, and the workpiece transport means. A protective film forming means for forming a protective film on the support surface of the wafer, and a holding surface for holding the wafer on which the protective film is formed by the protective film forming means are provided between the workpiece loading / unloading area and the processing area. A chuck table that is configured to be movable, a chuck table moving mechanism that moves the chuck table to a workpiece loading / unloading region and a processing region, and a workpiece that temporarily places a wafer on which a protective film is formed and performs centering The wafer on which the wafer on which the protective film centered by the workpiece temporary placing means and the workpiece temporary placing means is formed is positioned in the workpiece loading / unloading area A workpiece carrying means for conveying to the table and a turning tool provided with a bite tool for turning a protective film formed on the support surface of the wafer disposed on the chuck table disposed in the processing region and positioned in the processing region A turning unit feeding mechanism for moving the turning unit forward and backward in a direction perpendicular to the holding surface of the chuck table;
The protective film forming means forms a protective film by supplying a liquid resin to the support surface of the wafer and coating the resin protective film, followed by solidification.
The turning unit turns the surface of the protective film formed on the support surface of the wafer to make the thickness uniform.
A protective film forming apparatus is provided.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a wafer grinding method and a protective film forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

A workpiece conveying means 14 is disposed between the cassette placing area 11a and the workpiece temporary placing area 12a. The workpiece conveying means 14 is placed in the cassette placing area 11a. The unprocessed wafer stored in the cassette 11 is carried out to the workpiece temporary placement means 12, and the processed wafer cleaned by the cleaning means 13 is transferred to the cassette 11 placed in the cassette placement region 11a. To do. A workpiece carry-in means 15 is disposed between the workpiece temporary placement region 12a and the workpiece carry-in / out region 24. The workpiece carry-in means 15 is a workpiece temporary placement means 12. The unprocessed wafer placed on the workpiece is transferred onto the chuck table 52 of the chuck table mechanism 5 positioned in the workpiece loading / unloading region 24. A workpiece unloading means 16 is disposed between the workpiece loading / unloading area 24 and the cleaning unit 13a. The workpiece unloading means 16 is positioned in the workpiece loading / unloading area 24. The processed wafer placed on the chuck table 52 is transferred to the cleaning means 13.

As described above, when the protective film flattening step is completed, the turning unit 3 is raised. Next, the chuck table 52 is moved in the direction indicated by the arrow 23b in FIG. 2 to be positioned in the workpiece loading / unloading area 24, and the wafer 10 that has been subjected to the protective film flattening process on the chuck table 52 is sucked and held. To release. Then, the wafer 10 whose suction holding is released is carried out by the workpiece carrying-out means 16 and conveyed to the cleaning means 13. The wafer 10 conveyed to the cleaning means 13 is cleaned and spin-dried here. The wafer 10 cleaned and spin-dried by the cleaning unit 13 is stored in a predetermined position of the cassette 11 by the workpiece transfer unit 14.

Claims (1)

A wafer grinding method for grinding a surface to be ground of a wafer,
A protective film forming step of forming a protective film on the support surface by coating and solidifying a liquid resin on the support surface opposite to the surface to be ground of the wafer;
A protective film flattening step for turning the surface of the protective film formed on the support surface opposite to the surface to be ground of the wafer to make the thickness of the protective film uniform;
A grinding step in which a protective film side formed on a support surface opposite to the surface to be ground of the wafer is held on a chuck table of a grinding device and the surface to be ground of the wafer is ground by a grinding means.
A method for grinding a wafer.