KR20130018552A - Method for machining wafer - Google Patents

Abstract

PURPOSE: A method for processing a wafer is provided to secure a uniform wafer by grinding the back side of the wafer without exposing a copper electrode. CONSTITUTION: Liquid resin(321) is coated on a substrate(3) to protect the surface of the substrate(21). The back side(21b) of the substrate is exposed on a chuck table. A grinding wheel grinds the back side of the substrate.

Description

Wafer processing method {METHOD FOR MACHINING WAFER}

TECHNICAL FIELD This invention relates to the processing method of the wafer in which the electrode connected to the bonding pad respectively provided in the some device formed in the surface of the board | substrate was embedded.

In the semiconductor device manufacturing process, a plurality of regions are partitioned by a division scheduled line called a street arranged in a lattice shape on the surface of a silicon (Si) substrate having a substantially disk shape, and semiconductor devices such as IC and LSI are divided into the partitioned regions. To form. As described above, by cutting a wafer in which a plurality of semiconductor devices are formed on a surface of a silicon (Si) substrate along a street, an area in which the semiconductor device is formed is divided to manufacture individual semiconductor devices.

In order to miniaturize and high functionalize a device, the module structure which laminated | stacks several devices and connects the bonding pad provided in the laminated device is utilized. This module structure forms a hole (via hole) in a place where a bonding pad in a silicon (Si) substrate is provided, and connects an electrode such as copper or aluminum to the hole (via hole) to connect the bonding pad with silicon dioxide (Si0). _It is the structure which coat | covers and embeds by the insulating material which consists of ₂ ) (for example, refer patent document 1).

As described above, in order to expose the copper (Cu) electrode embedded in the silicon (Si) substrate to the back surface of the silicon (Si) substrate, the back surface of the silicon (Si) substrate is ground to expose the copper electrode on the back surface. After that, the back surface of the silicon (Si) substrate is etched using potassium hydroxide (KOH) having a high etching rate for silicon (Si) and a low etching rate for copper (Cu) as an etching solution. It forms in predetermined thickness, and protrudes a copper (Cu) electrode about 10 micrometers from a back surface (for example, refer patent document 2).

[Patent Document 1] Japanese Unexamined Patent Publication No. 2003-249620 [Patent Document 2] Japanese Unexamined Patent Publication No. 2003-l88134

As described above, when the back surface of the substrate is ground and the electrode is exposed on the back surface, there is a problem that metal atoms enter the inside of the substrate and degrade the device quality when the electrode is ground. Therefore, when grinding the back surface of the substrate, it is important to finish the grinding at a position immediately before reaching the electrode, for example, a position that is less than about 3 mu m from the front end of the back side of the electrode so as not to expose the electrode to the back surface of the substrate.

Moreover, when grinding the back surface of a board | substrate, in order to protect the device formed in the surface of a board | substrate, the substrate which consists of a glass plate etc. is bonded to the surface of a board | substrate through liquid resin, and this protection member side is attached to the chuck table of a grinding apparatus. Then, the back surface of the upper substrate is ground.

By the way, since it is difficult to apply the liquid resin for bonding a substrate to the surface of a board | substrate with a uniform thickness, the back surface of the board | substrate with which the surface was bonded to the substrate produces wrinkles along the thickness of a liquid resin. For this reason, the height position of the front end of the back side of the electrode embedded in the board | substrate does not become uneven, but the electrode which grinds when grinding the back surface of a board | substrate arises. As a result, there arises a problem that metal atoms enter the inside of the substrate and degrade the quality of the device.

This invention is made | formed in view of the said fact, The main technical subject does not grind and expose all the electrodes embedded in the board | substrate which comprises a wafer, and finishes grinding in the position which falls slightly below the front end of the back surface of an electrode of a board | substrate. It is to provide a wafer processing method which can be performed.

MEANS TO SOLVE THE PROBLEM In order to solve the said main technical subject, according to this invention, as the wafer processing method which forms the wafer in which the electrode connected to the bonding pad respectively provided in the some device formed in the surface of the board | substrate is embedded in the said board | substrate to predetermined thickness. ,

A liquid resin coating step of coating the liquid resin on the surface of the substrate by dropping and rotating the liquid resin on the surface of the substrate for protecting the surface of the substrate;

A substrate bonding step of bonding the surface of the substrate to the surface of the substrate coated with a liquid resin through a liquid resin;

A height position measurement step of measuring a height position from the substrate on the back surface of the substrate on which the surface of the substrate is bonded through a liquid resin;

A wafer holding step of arranging the substrate side bonded to the surface of the substrate on a chuck table of a grinding apparatus, exposing the back surface of the substrate and holding the substrate on the chuck table;

The grinding surface of the grinding wheel is brought into contact with the rear surface of the substrate of the wafer while the grinding wheel is rotated to rotate the grinding wheel to the rear surface of the substrate of the wafer held on the chuck table. Includes the back grinding process,

Before performing the said back grinding process, the said board | substrate based on the height position from the said substrate in the back surface of the said board | substrate with which the surface of the said substrate measured by the said height position measuring process was bonded through the liquid resin. A slope from the outer circumference side to the center side on the back surface of the surface is determined, and a face state adjustment step of adjusting the facing state of the holding surface of the chuck table and the grinding surface of the grinding wheel in response to the slope is performed. A processing method of a wafer is provided.

Moreover, according to this invention, the wafer processing method of forming the wafer in which the electrode connected to the bonding pads respectively provided in the some device formed in the surface of the board | substrate is embedded in the said board | substrate to predetermined thickness,

A liquid resin coating step of coating the liquid resin on the surface of the substrate by dropping and rotating the liquid resin on the surface of the substrate for protecting the surface of the substrate;

A substrate bonding step of bonding the surface of the substrate to the surface of the substrate coated with a liquid resin through a liquid resin;

A height position measurement step of measuring a height position from the substrate on the rear end surface of the back surface of the electrode embedded in the substrate on which the surface of the substrate is bonded through a liquid resin;

A wafer holding step of arranging the substrate side bonded to the surface of the substrate on a chuck table of a grinding apparatus, exposing the back surface of the substrate and holding the substrate on the chuck table;

The grinding surface of the grinding wheel is brought into contact with the rear surface of the substrate of the wafer while the grinding wheel is rotated to rotate the grinding wheel to the rear surface of the substrate of the wafer held on the chuck table. Includes the back grinding process,

Before performing the said back grinding process, the outer peripheral side in the back side end surface of an electrode based on the height position from the said substrate of the back side end surface in the said electrode measured by the said height position measuring process. And a slope from the center to the center side, and a face state adjustment step of adjusting the face state of the holding surface of the chuck table and the grinding surface of the grinding wheel in response to the slope is provided. .

The present invention is a wafer processing method for forming a wafer having a predetermined thickness of a wafer in which electrodes connected to bonding pads respectively provided on a plurality of devices formed on a surface of a substrate are embedded in a substrate, and having a substrate for protecting the surface of the substrate. A liquid resin coating process of coating a liquid resin on the surface of the substrate by dropping and rotating a liquid resin on the surface of the substrate, and a substrate bonding bonding the surface of the substrate to the surface of the substrate coated with the liquid resin through the liquid resin. The height side measurement process which measures the height position from the substrate in the back surface of the board | substrate with which the surface of the substrate was bonded through liquid resin, and the substrate side joined to the surface of a board | substrate to the chuck table of a grinding apparatus. And expose the back side of the substrate to hold it on the chuck table. Wafer holding step and back grinding for grinding the back surface of the wafer by contacting the grinding surface of the wafer with the back surface of the wafer while rotating the grinding wheel on the back surface of the wafer held on the chuck table by rotating the chuck table. Process, wherein the surface of the substrate, measured by the height position measurement process, prior to performing the back surface grinding process, is based on the height position from the substrate on the back surface of the substrate bonded through the liquid resin. Since the inclination from the outer peripheral side to the center side in the back surface is calculated | required, and the face state adjustment process which adjusts the facing state of the holding surface of a chuck | zipper table and the grinding surface of a grinding wheel corresponding to this inclination is performed, The back surface (grinding surface) of the substrate is ground uniformly, and the wafer is ground to uniform thickness. Therefore, not all electrodes are exposed by finishing grinding at the position less than 3 micrometers, for example from the front end of the back surface side of the board | substrate of the electrode embedded in the board | substrate which comprises a wafer.

Moreover, according to this invention, in the height position measurement process, the height position from the substrate of the back side end surface in the electrode embedded in the board | substrate with which the surface of the substrate was bonded via the liquid resin is measured, and this height position The slope from the outer circumferential side to the center side in the rear end surface of the electrode is determined based on the above, and the state of facing of the holding surface of the chuck table and the grinding surface of the grinding wheel is adjusted to correspond to the slope. Even if there is a deviation in the height of the electrode, and there is a deviation in the distance from the back surface of the substrate, the electrode is not ground and exposed in the back surface grinding step.

1 is a perspective view of a semiconductor wafer processed by a wafer processing method according to the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part of the semiconductor wafer shown in FIG. 1; FIG.
3 is an explanatory diagram of a liquid resin coating step in a wafer processing method according to the present invention.
4 is an explanatory diagram of a substrate bonding step in the wafer processing method according to the present invention.
5 is a perspective view of a grinding device for performing a height position measurement step and a back surface grinding step in a wafer processing method according to the present invention.
FIG. 6 is a perspective view of the chuck table mechanism provided in the grinding apparatus shown in FIG. 5. FIG.
FIG. 7 is a plan view of the chuck table support mechanism constituting the chuck table mechanism shown in FIG. 5; FIG.
8 is a cross-sectional view of the chuck table constituting the chuck table mechanism shown in FIG. 5.
FIG. 9 is a block diagram of control means provided in the grinding apparatus shown in FIG. 5. FIG.
10 is an explanatory diagram of a height position measurement step in the wafer processing method according to the present invention.
FIG. 11 is an explanatory diagram showing the height position of the back surface of the silicon (Si) substrate constituting the semiconductor wafer measured by the height position measurement process shown in FIG. 10; FIG.
Fig. 12 is a cross-sectional view showing a state in which a substrate of a semiconductor wafer on which a surface of a substrate is bonded through a liquid resin is held on a holding surface of a chuck table.
FIG. 13 is an explanatory diagram of a face state adjustment step and a back surface grinding step performed in the grinding apparatus shown in FIG. 5. FIG.
14 is an explanatory diagram showing another embodiment of the height position measurement step in the wafer processing method according to the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of the wafer processing method and grinding apparatus which concern on this invention is described in detail with reference to an accompanying drawing.

1 is a perspective view of a semiconductor wafer processed by a method for processing a wafer in which an electrode according to the present invention is embedded. In the semiconductor wafer 2 shown in FIG. 1, a plurality of regions are partitioned by a street 211 formed in a lattice shape on the surface 21a of a silicon (Si) substrate 21 having a thickness of, for example, 600 μm. Devices 212, such as IC and LSI, are respectively formed in the partitioned area. A plurality of bonding pads 213 are provided on the surface of the device 212 formed as described above. In the semiconductor wafer 2 thus formed, as illustrated in FIG. 2, a copper (Cu) electrode 214 connected to the bonding pad 213 is embedded in the silicon (Si) substrate 21. In addition, the copper (Cu) electrode 214 embedded in the silicon (Si) substrate 21 has a length of, for example, 200 μm, and the silicon dioxide (Si0 ₂ ) film 215 as an insulating film has a thickness of about 150 nm. It is covered with a thickness.

Hereinafter, the wafer processing method which grinds the back surface of the silicon (Si) board | substrate 21 which comprises the semiconductor wafer 2 mentioned above, and forms it to predetermined thickness, without exposing the copper (Cu) electrode 214 is demonstrated. .

First, a liquid resin coating step of coating a liquid resin on the surface of the substrate is performed by dropping and rotating the liquid resin on the surface of the substrate for protecting the surface of the silicon (Si) substrate 21. This liquid resin coating process is performed using the protective film coating apparatus 30 shown to Fig.3 (a) and (b). The protective film coating apparatus 30 shown to Fig.3 (a) and (b) is the spinner table 31 holding a wafer, and the liquid resin arrange | positioned above the rotation center of the said spinner table 31. The supply nozzle 32 is provided. In order to perform the liquid resin coating process using the protective film coating device 30 configured as described above, as shown in Fig. 3A, the spinner table 31 is formed of a sub-plate which is, for example, about 1 mm thick. The back surface 3b side of the straight 3 is arrange | positioned. Then, suction means (not shown) is operated to suck and hold the substrate 3 on the spinner table 31. Therefore, in the substrate 3 held on the spinner table 31, the surface 3a becomes the upper side. In this way, if the substrate 3 is held on the spinner table 31, a predetermined rotational speed (for example, 300 to 300) is shown in the direction indicated by the arrow as shown in Fig. 3A. A predetermined amount of a predetermined amount of the liquid resin 320 in the center region of the surface 3a of the substrate 3 from the liquid resin supply nozzle 32 disposed above the spinner table 31 while rotating at 1000 rpm). Dropping Then, by rotating the spinner table 31 for about 60 seconds, the resin layer 321 is formed on the surface 3a of the substrate 3 as shown in Fig. 3B. Although the thickness of the resin layer 321 which coat | covers the surface 3a of the substrate 3 is determined according to the dripping amount of the said liquid resin 320, it is good as about 50 micrometers. As the liquid resin 320, ethylene carbonate, an epoxy resin, a resist resin, or the like can be used. In this way, the resin layer 321 coated on the surface 3a of the substrate 3 is not uniform in thickness, and as described above, the liquid resin 320 dropped in the central region flows to the outer peripheral portion by centrifugal force. As shown in Fig. 3 (c), the surface 321a is concave and the thickness is gradually thickened from the center toward the outer circumference. In addition, the resin layer 321 coated on the surface 3a of the substrate 3 has a surface as shown in FIG. 3D when the rotation speed of the spinner table 31 is slow and the rotation time is short. 321a may become a convex shape, and the center part may be thick and it may become thin toward the outer periphery.

If the above-mentioned liquid resin coating process was performed, the substrate bonding process which joins the surface of the silicon (Si) substrate 21 to the surface of the substrate 3 which coat | covered the liquid resin through liquid resin is performed. That is, as shown in FIGS. 4A and 4B, the surface of the silicon (Si) substrate 21 is formed on the surface of the substrate 3 coated with the resin layer 321. Bond through. In this manner, the silicon (Si) substrate 21 having a thin thickness (600 μm in the illustrated embodiment) bonded to the surface of the substrate 3 via the resin layer 321 is described above. As mentioned above, since the center part is thick and becomes thin toward the outer periphery, it joins along this resin layer 321. Therefore, the resin layer 321 coated on the surface of the substrate 3 has a concave shape in which the surface 321a is concave, as shown in Fig. 3C, and the thickness is gradually thickened from the center toward the outer circumference. In this case, as shown in Fig. 4C, the rear surface 21b, which is the upper surface of the silicon (Si) substrate 21, has a concave shape, so that the center portion is low and increases toward the outer circumference. On the other hand, when the resin layer 321 coated on the surface of the substrate 3 has a convex shape as shown in Fig. 3 (d), the center part becomes thick and becomes thin toward the outer circumference, (d) As shown in Fig. 2), the back surface 21b, which is the upper surface of the silicon (Si) substrate 21, becomes convex, has a high central portion and is lowered toward the outer circumference.

As described above, when the surface of the silicon (Si) substrate 21 is bonded to the surface of the substrate 3 through the resin layer 321, the back surface of the silicon (Si) substrate 21 is ground to a predetermined thickness. The back surface grinding process to be formed is performed. This back surface grinding process is performed using the grinding apparatus 4 shown in FIG. The grinding apparatus 4 shown in FIG. 5 is equipped with the apparatus housing which shows the whole number 40. FIG. The device housing 40 has a rectangular parallelepiped main part 41 and an upstanding wall 42 which is provided at the rear end of the main part 41 (upper right side in FIG. 5) and extends upward. ) On the front surface of the upstanding wall 42, a pair of guide rails 421 and 421 extending in the vertical direction are provided. The grinding unit 5 as a grinding means is attached to this pair of guide rails 421 and 421 so that a movement to an up-down direction is possible.

The grinding unit 5 is equipped with the moving base 51 and the spindle unit 52 attached to the said moving base 51. The moving base 51 is provided with a pair of leg parts 511 and 511 extending on both sides of the rear surface in the vertical direction, and the pair of guide rails 421 are provided on the pair of leg parts 511 and 511. , 421 and the guide grooves 512 and 512 to be slidably engaged are formed. Thus, the support part 513 protruding forward is provided in the front surface of the movable base 51 slidably mounted to the pair of guide rails 421 and 421 provided in the upstanding wall 42. The spindle unit 52 is attached to this support part 513.

The spindle unit 52 includes a spindle housing 521 mounted to the support portion 513, a rotary spindle 522 rotatably installed on the spindle housing 521, and a drive for rotationally driving the rotary spindle 522. The servo motor 523 is provided as a rotation drive means. The lower end of the rotary spindle 522 protrudes downward beyond the lower end of the spindle housing 521, and a mounter 524 is provided at the lower end thereof. The grinding wheel 525 is mounted on the lower surface of the mounter 524. The grinding wheel 525 consists of an annular base 526 and a grinding grindstone 527 annularly mounted on the lower surface of the base 526, and the annular base 526 is fastened to the mounter 524 by a fastening bolt ( 528).

The grinding apparatus 4 shown in FIG. 5 is provided with the grinding feed means 6 which moves the grinding unit 5 to an up-down direction along the pair of guide rails 421 and 421. This grinding feed means 6 is provided with the external threaded rod 61 provided in the front side of the upstanding wall 42, and extending in an up-down direction. The male screw rod 61 is rotatably supported by bearing members 62 and 63 whose upper and lower ends are attached to the upstanding wall 42. The upper bearing member 62 is provided with a pulse motor 64 as a drive source for rotationally driving the male screw rod 61, and the output shaft of the pulse motor 64 is electrically connected to the male screw rod 61. A connecting portion (not shown) is also formed on the rear surface of the movable base 61 to protrude rearward from the center portion in the width direction, and the connecting portion is formed with a through female thread hole extending in the vertical direction, and the male screw hole is formed in the female screw hole. The rod 61 is screwed in. Accordingly, when the pulse motor 64 rotates forward, the moving base 51, that is, the grinding unit 5, moves down, that is, when the pulse motor 64 reversely rotates, the moving base 51, that is, the grinding unit 5. ) Rises, ie retracts.

5 and 6, the chuck table mechanism 7 is provided at the rear half of the main portion 41 of the device housing 40. The chuck table mechanism 7 includes a movement base 71 and a chuck table 73 supported by the chuck table support mechanism 72 on the movement base 71. The moving base 71 has a pair of guide rails 43 extending to the rear half of the main portion 41 in the directions indicated by arrows 43a and 43b in the front-rear direction (the direction perpendicular to the front face of the upstanding wall 42). 43, which is slidably mounted and constitutes a workpiece loading / unloading area 44 shown in FIG. 5 by the chuck table mechanism moving means 76 described later and a grinding wheel ( It is moved between the grinding grindstone 527 of 525 and the opposing grinding area 45.

The chuck table support mechanism 72 includes a chuck table support plate 721, a cylindrical member 722 provided on the chuck table support plate 721 to rotatably support the chuck table 73, and a chuck table support plate ( The support means 723 which supports the 721 on the movement base 71 is provided. The support means 723 consists of a three point support mechanism supported by three support parts 724a, 724b, and 724c, as shown in FIG. The first support portion 724a is a point portion, and the second support portion 724b and the third support portion 724c are movable portions. The second support part 724b and the third support part 724c which are movable parts are supported by the vertical position adjusting means 725 and 726, as shown in FIG. The vertical position adjusting means 725 and 726 consist of a pulse motor and the screw mechanism actuated by this pulse motor, for example. Accordingly, by operating the vertical position adjusting means 725 and 726, respectively, by adjusting the height positions of the second support portion 724b and the third support portion 724c, the posture of the chuck table 73, that is, the chuck table 73 to be described later. The facing state of the grinding surface which is the lower surface of the grinding surface 527 which comprises the holding surface of the () and the said grinding wheel 525 can be adjusted. Therefore, the support means 723 including the up-down position adjusting means 725 and 726 functions as a face state adjustment means for adjusting the facing state of the holding surface of the chuck table 73 and the grinding surface of the grinding wheel 525. do.

Next, the chuck table 73 is demonstrated with reference to FIG.

The chuck table 73 shown in FIG. 8 consists of a cylindrical chuck table main body 731 and a circular suction adsorption chuck 732 provided in the upper surface of this chuck table main body 731. The chuck table main body 731 is formed of metal materials, such as stainless steel, the circular fitting recess 731a is formed in the upper surface, and the annular arrangement shelf of the bottom surface outer peripheral part of this fitting recess 731a is carried out. 731b is provided. Then, the suction retention chuck 732 formed by the porous member made of porous ceramics having a myriad suction holes in the fitting recess 731a is fitted. In this way, the suction holding chuck 732 fitted to the fitting recess 731a of the chuck table main body 731 has the upper surface holding surface 732a exaggerated in FIG. It is formed into a conical shape as a vertex. In the conical holding surface 732a, when the radius is set to R and the height of the vertex is set to H, the inclination (H / R) from the outer circumference to the center is set to 0.0002 in the illustrated embodiment. In addition, in the illustrated embodiment, the diameter of the suction holding chuck 732 is set to 200 mm (radius R: 100 mm) and the height H is set to 20 µm. The inclination H / R from the outer circumference to the center of the holding surface 732a of the chuck table 73 set as described above is stored in a random access memory (RAM) of the control means described later. Moreover, the communication path 731c which communicates with the fitting recessed part 731a is formed in the chuck table main body 731, and this communication path 731c is connected to the suction means which is not shown in figure. Therefore, the workpiece is sucked and held on the holding surface 732a by arranging the workpiece on the holding surface 732a which is the upper surface of the suction holding chuck 732 and operating the suction means (not shown). The chuck table 73 configured in this way is rotated by the servo motor 74 provided in the cylindrical member 722 shown in FIG.

Continuing with reference to FIG. 6, the illustrated grinding device 4 moves the chuck table mechanism 7 in parallel with a holding surface that is an upper surface of the chuck table 73 along a pair of guide rails 43. The chuck table mechanism movement means 76 which moves in the direction shown by the arrow 43a and 43b is provided. The chuck table mechanism moving means 76 is provided between a pair of guide rails 43 and extends in parallel with the guide rails 43, and a servo for rotationally driving the external thread rods 761. The motor 762 is provided. The male thread rod 761 is screwed with the screw hole 711 provided in the said movement base 71, and is provided by the bearing member 763 to which the front-end part connected and connected a pair of guide rails 43 and 43, respectively. It is rotatably supported. The drive shaft of the servo motor 762 is electrically connected to the base end of the male screw rod 761. Accordingly, when the servo motor 762 rotates forward, the moving base 71, that is, the chuck table mechanism 7 moves in the direction indicated by arrow 43a, and when the servo motor 762 rotates backward, the moving base 71, that is, The chuck table mechanism 7 is moved in the direction indicated by arrow 43b. The chuck table mechanism 7 moved in the directions indicated by the arrows 43a and 43b is selectively positioned in the workpiece loading / unloading region 44 and the grinding region 45 in FIG. 5.

With continued description based on FIG. 5, the grinding device 4 in the illustrated embodiment includes a first cassette 11 and a front half of the main portion 41 of the device housing 40. The second cassette 12, the workpiece temporary mounting means 13, the cleaning means 14, the workpiece conveyance means 15, the workpiece loading means 16, and the workpiece removal means 17 It is installed. The 1st cassette 11 accommodates the to-be-processed object before a grinding process, and is arrange | positioned in the cassette loading area in the main part 41 of the apparatus housing 40. As shown in FIG. In addition, the first cassette 11 accommodates the semiconductor wafer 2 in which the surface of the silicon (Si) substrate 21 is bonded to the surface of the substrate 3 described above through the resin layer 321. The 2nd cassette 12 is arrange | positioned in the cassette carrying area in the main part 41 of the apparatus housing 40, and accommodates the semiconductor wafer 2 after a grinding process. The workpiece temporary mounting means 13 is provided between the first cassette 11 and the workpiece loading and unloading area 44 to temporarily hold the semiconductor wafer 2 before grinding. The cleaning means 14 is provided between the workpiece loading and unloading area 44 and the second cassette 12 to clean the semiconductor wafer 2 after the grinding process. The workpiece conveyance means 15 is provided between the first cassette 11 and the second cassette 12 to transfer the semiconductor wafer 2 contained in the first cassette 11 to the workpiece temporary placing means 13. It carries out and conveys the semiconductor wafer 2 wash | cleaned by the washing | cleaning means 14 to the 2nd cassette 12.

The workpiece loading means 16 is provided between the workpiece temporary mounting means 13 and the workpiece loading and unloading area 44, and the semiconductor wafer before grinding processing disposed on the workpiece temporary placing means 13 2) is conveyed on the chuck table 73 of the chuck table mechanism 7 located in the workpiece carry-in / out area 44. The workpiece carry-out means 17 is provided between the workpiece carry-in and take-out area 44 and the cleaning means 14, and is disposed on the chuck table 73 located in the workpiece carry-in and take-out area 44. The semiconductor wafer 2 after the grinding process is conveyed to the cleaning means 14.

Moreover, the 1st cassette 11 which accommodated the predetermined number of semiconductor wafers 2 before grinding process is arrange | positioned in the predetermined cassette loading area in the main part 41 of the apparatus housing 40. As shown in FIG. And when all the semiconductor wafers 2 before grinding processing accommodated in the 1st cassette 11 arrange | positioned at a cassette carrying-in area | region are carried out, the several semiconductor wafers 2 before grinding processing are predetermined instead of the empty cassette 11. The new cassette 11, which has been received, is manually placed in the cassette loading area. On the other hand, when the predetermined number of semiconductor wafers 2 after grinding processing are carried in to the 2nd cassette 12 arrange | positioned in the predetermined cassette carrying area in the main part 41 of the apparatus housing 40, such a 2nd cassette 12 will be carried. ) Is manually taken out and a new empty second cassette 12 is placed.

With continued description with reference to FIG. 5, the grinding apparatus 4 in the illustrated embodiment is a ground surface or a semiconductor of the semiconductor wafer 2 before the grinding processing disposed on the workpiece temporary placing means 13. The height position measuring means 8 which measures the height position of the copper (Cu) electrode 214 embedded in the silicon (Si) board | substrate 21 which comprises the wafer 2 is provided. The height position measuring means 8 is the back surface 21b (blood of the silicon (Si) substrate 21 constituting the semiconductor wafer 2 bonded to the surface of the substrate 3 via the resin layer 321. Height from the surface 3a of the substrate 3 in the grinding surface, or the back (grinding surface) side in the copper (Cu) electrode 214 embedded in the silicon (Si) substrate 21. The height position of the end face is measured. As such a height position measuring apparatus, TSV300-IR manufactured and sold by Laser Tech Co., Ltd. can be used, for example.

The grinding apparatus 4 in the illustrated embodiment is provided with the control means 9 shown in FIG. 9. The control means 9 is comprised by the computer, The central processing unit (CPU) 91 which performs arithmetic processing according to a control program, the read-only memory (ROM) 92 which stores a control program, etc., and a calculation result And a recordable and readable random access memory (RAM) 93 for storing a back and the like, and an input interface 94 and an output interface 95. The detection signal is input to the input interface 94 of the control means 9 comprised in this way from the height position measuring means 8 etc. Further, from the output interface 95, the vertical position adjustment for supporting the electric motor 523 for rotationally driving the rotary spindle 522, the pulse motor 64 of the grinding feed means 6, and the chuck table 73 is supported. The means 725 and 726, the servo motor 74 for rotationally driving the chuck table 73, the servo motor 762 of the chuck table mechanism moving means 76, the height position measuring means 8, the temporary mounting of the workpiece The control signal is output to the means 13, the spinner cleaning means 14, the workpiece conveyance means 15, the workpiece loading means 16, the workpiece removal means 17, and the like.

The grinding apparatus 4 in embodiment shown is comprised as mentioned above, and the operation | movement is demonstrated below.

Back surface 21b of the silicon (Si) substrate 21 constituting the semiconductor wafer 2 bonded to the surface of the substrate 3 through the resin layer 321 by the aforementioned grinding device 4. In order to grind the grinding surface), the cassette 11 in which the semiconductor wafer 2 bonded to the surface of the substrate 3 before the grinding process is accommodated is placed in a predetermined cassette placing portion. In addition, the semiconductor wafer 2 bonded to the surface of the substrate 3 accommodated in the cassette 11 via the resin layer 321 is a silicon (Si) substrate (as shown in FIG. 4C). The back surface 21b, which is the upper surface of 21), is described as having a concave shape, with the center portion being low and rising toward the outer circumference.

As described above, when the cassette 11 containing the semiconductor wafer 2 bonded to the surface of the substrate 3 before the grinding process is placed in a predetermined cassette arrangement unit, and a grinding start switch (not shown) is put in, The control means 9 operates the workpiece conveyance means 15 to hold the semiconductor wafer 2 bonded to the surface of the substrate 3 before grinding contained in the cassette 11. Return to And the control means 9 operates the workpiece temporary mounting means 13, and performs centering of the semiconductor wafer 2 bonded to the surface of the substrate 3 before grinding conveyed. Next, the control means 9 is the back surface 21b (blood of the silicon (Si) substrate 21 constituting the semiconductor wafer 2 bonded to the surface of the substrate 3 via the resin layer 321. The height position measurement process of measuring the height position from the substrate 3 in a grinding surface) is performed. That is, the control means 9 operates the height position measuring means 8 to form the semiconductor wafer 2 in which the detector 81 is bonded to the surface of the substrate 3 as indicated by the solid line in FIG. 10. It is located in the outer peripheral edge of the silicon (Si) substrate 21. Thus, the detection part 81 of the height position measuring means 8 located in the outer peripheral edge part of the silicon (Si) board | substrate 21 is the back surface 21b (grinding surface) of the silicon (Si) board | substrate 21. The height H1 of the outer circumferential edge portion in the edge is detected, and the height position signal is sent to the control means 9. Next, the control means 9 positions the detector 81 in the center of the silicon (Si) substrate 21 constituting the semiconductor wafer 2 as indicated by the dashed-dotted line in FIG. 10. Thus, the detection part 81 located in the center of the silicon (Si) board | substrate 21 which comprises the semiconductor wafer 2 is in the back surface 21b (grinding surface) of the silicon (Si) board | substrate 21. The height H2 of the center of the signal is detected and a height position signal is sent to the control means 9. The control means 9 is the height H1 data of the outer peripheral edge part on the back surface 21b (grinding surface) of the silicon (Si) substrate 21 sent from the height position measuring means 8, and the height of the center ( H2) The data is stored in the random access memory (RAM) 93. And the control means 9 subtracts the height H2 of the center from the height H1 of the outer peripheral edge part in the back surface 21b (grinding surface) of the silicon (Si) board | substrate 21, and silicon | silicone (Si) The height difference h of the concave shape in the back surface 21b (grinding surface) of the board | substrate 21 is calculated | required (h = H1-H2). Thus, if the height difference h of the concave shape in the back surface 21b (grinding surface) of the silicon (Si) board | substrate 21 was calculated | required, the control means 9 will be a silicon (Si) board | substrate 21. The inclination h / R is obtained from the radius R and the height difference h, and the inclination h / R is stored in the random access memory (RAM) 93. 11 shows the height H1 of the outer peripheral edge portion, the height H2 of the center and the silicon (Si) substrate 21 of the rear surface 21b (grinding surface) of the silicon (Si) substrate 21. The inclination (h / R) from the outer periphery to the center on the back surface 21b (grinding surface) is shown. In the embodiment shown in FIG. 11, the height H1 from the substrate 3 of the outer peripheral edge portion of the back surface 21b (grinding surface) of the silicon (Si) substrate 21 is 610 µm and silicon. (Si) The height H2 from the center substrate 3 on the back surface 21b (grinding surface) of the substrate 21 is 607 m, and the height difference h is 3 m. Therefore, when the radius R of the silicon (Si) substrate 21 is 100 mm, the inclination (h / R = 0.003 / 100) is 0.00003.

Height position which measures the height position in the back surface 21b (grinding surface) of the silicon (Si) board | substrate 21 which comprises the semiconductor wafer 2 bonded to the surface of the substrate 3 as mentioned above. When the measurement process is performed, the control means 9 operates the workpiece conveyance means 15 to suck and hold the semiconductor wafer 2 subjected to the height position measurement process, and is located in the carry-in / out area 44. It conveys on the chuck table 73. At this time, the substrate 3 side bonded to the semiconductor wafer 2 is disposed on the chuck table 73, and the back surface 21b (grinding surface) of the silicon (Si) substrate 21, which is the grinding surface, is disposed. This is the upper side. Thus, the semiconductor wafer 2 before grinding arrange | positioned on the chuck table 73 located in the carrying-in / out area 44 is carried out by the suction means which is not shown in figure, and as shown in FIG. 73 is sucked and held through the substrate 3 (wafer holding step). Thus, the semiconductor wafer 2 before the grinding process attracted and held by the substrate 3 on the chuck table 73 has a conical shape in the illustrated embodiment. That is, the inclination (H / R) of the holding surface 732a of the chuck table 73 is 0.0002, and the semiconductor wafer 2 bonded to the surface of the substrate 3 has the inclination (h / R) as described above. Is 0.00003, the back surface of the silicon (Si) substrate 21, which is the upper surface of the semiconductor wafer 2 before grinding, sucked and held on the holding surface 732a of the chuck table 73 through the substrate 3. 21b) (grinding surface) has comprised conical shape as shown in FIG.

If the semiconductor wafer 2 before grinding is sucked and held on the chuck table 73, the control means 9 operates the chuck table mechanism moving means 76 to move the chuck table mechanism 7 in the direction indicated by the arrow 43a. It is moved and positioned in the grinding area 45. Next, the control means 9 controls the grinding wheel 525 and the rear surface 21b of the silicon (Si) substrate 21, which is the processing surface of the semiconductor wafer 2 held on the holding surface of the chuck table 73. The face state adjustment process of adjusting the face state of a grinding surface is implemented. This face-to-face state adjustment process is an outer periphery in the said inclination H / R of the holding surface 732a of the said chuck table 73, and the back surface 21b (grinding surface) of the silicon (Si) substrate 21. Vertical position adjusting means 725 functioning as a facing state adjusting means for adjusting the facing state of the holding surface of the chuck table 73 and the grinding surface of the grinding wheel 525 based on the inclination h / R from the center to the center (h / R). And 726, including support means 723. Since the grinding surface which is the lower surface of the grinding surface 5732 which comprises the grinding surface 732a of the chuck table 73 and the grinding wheel 525 is positioned so that it may become basically parallel, the holding surface of the chuck table 73 ( Face state adjustment to correct the difference between the slope H / R of 732a and the slope h / R from the outer circumference to the center of the back surface 21b (grinding surface) of the silicon (Si) substrate 21 By adjusting the vertical position adjusting means 725 and 726 functioning as means, the lower surface 21b (grinding surface) of the silicon (Si) substrate 21 and the lower surface of the grinding grindstone 527 as shown in FIG. The grinding surface can be positioned in parallel.

If the face state adjustment process was performed as described above, the control means 9 rotates the chuck table 73 holding the semiconductor wafer 2 in, for example, about 300 rpm in the direction indicated by the arrow 73a in FIG. The servo motor 523 is driven to rotate the rotating spindle 522 to rotate the grinding wheel 525 at a rotational speed of, for example, 6000 rpm in the direction indicated by the arrow 525a, and the pulse motor 64 of the grinding feed means 6. ) Is rotated forward to lower, that is, advance the grinding unit 5. At this time, the center of the chuck table 73, that is, the center of the silicon (Si) substrate 21 constituting the semiconductor wafer 2 is positioned at a position where the plurality of grinding grindstones 527 of the grinding wheel 525 pass. Let's do it. Then, the pulse motor 64 of the grinding feed means 6 is driven in the forward rotation to lower the grinding unit 5, ie, to advance it, and to move the plurality of grinding grindstones 527 of the grinding wheel 525 to the semiconductor wafer 2. It presses on the back surface 21b (grinding surface) of the silicon (Si) board | substrate 21 which comprises this at a predetermined load. As a result, the back surface 21b (grinding surface) of the silicon (Si) substrate 21 constituting the semiconductor wafer 2 is ground uniformly, and the semiconductor wafer 2 is ground to a uniform thickness (backside grinding). fair). Therefore, for example, about 3 μm from the front end of the back surface 21b side of the silicon (Si) substrate 21 of the copper (Cu) electrode 214 embedded in the silicon (Si) substrate 21 constituting the semiconductor wafer 2. By terminating grinding at an unsatisfactory position, not all the copper (Cu) electrodes 214 are exposed.

If the grinding process was performed as described above, the control means 9 drives the pulse motor 64 of the grinding feed means 6 in reverse rotation to raise the spindle unit 52 to a predetermined position, and the servo motor 523. ) Stops the rotation of the grinding wheel 525, and further stops the rotation of the chuck table (73).

Next, the control means 9 operates the chuck table mechanism moving means 76 shown in FIG. 6 to move the chuck table 73 in the direction indicated by the arrow 43b, thereby allowing the workpiece to be loaded and unloaded area 44 (FIG. 5). In this way, if the chuck table 73 is positioned in the workpiece loading and unloading area 44, the control means 9 releases suction holding of the semiconductor wafer 2 by the chuck table 73, and takes out the workpiece. The means 17 is operated to take out the semiconductor wafer 2 subjected to the grinding process from the chuck table 73 and is conveyed to the spinner cleaning means 14.

As described above, the semiconductor wafer 2 carried out from the chuck table 73 located in the workpiece loading / unloading region 44 and conveyed to the spinner cleaning means 14 is washed with the workpiece conveying means ( 15 is stored in the predetermined position of the second cassette 12.

Next, another embodiment of the height position measurement process will be described. This height position measurement process is performed in the copper (Cu) electrode 214 embedded in the silicon (Si) substrate 21 in which the surface of the substrate 3 is bonded through a liquid resin, as shown in FIG. The height position from the substrate 3 of the back side end surface is measured. At this time, the height position of the copper (Cu) electrode 214 embedded in the outer peripheral edge portion of the silicon (Si) substrate 21 and the height position of the copper (Cu) electrode 214 embedded in the center are obtained, and both heights are determined. Although the inclination may be obtained based on the position, the height position of the plurality of copper (Cu) electrodes 214 embedded between the outer peripheral edge of the silicon (Si) substrate 21 to the center portion is obtained, and the height position is connected. The inclination which the line which does not protrude neither copper (Cu) electrode 214 may be calculated | required. Thus, the copper (Cu) electrode 214 is measured by measuring the height position from the substrate 3 of the back end surface of the copper (Cu) electrode 214 embedded in the silicon (Si) substrate 21. ), The copper (Cu) electrode 214 is not ground and exposed in the back surface grinding step even if there is a deviation in the height and the distance from the back surface 21b of the silicon (Si) substrate 21. .

As described above, the semiconductor wafer 2 subjected to the backside grinding step is made of silicon (tetramethylammonium hydroxide (TMAH), which has a high etching rate for silicon and a very low etching rate for Si0 ₂ , as an etching solution. By etching the back surface of the Si) substrate 21, the copper (Cu) electrode 214 coated with Si0 ₂ is projected from the back surface by, for example, about 10 mu m. Then, after forming an insulating film of SiO ₂ on the entire back surface of the silicon (Si) substrate 21, the copper (Cu) electrode 214 is exposed from the insulating film by polishing, and the exposed copper (Cu) electrode 214 The bump is squeezed to the end face.

2: semiconductor wafer
21: silicon (Si) substrate
212 device
213: Bonding Pads
214: copper (Cu) electrode
215 silicon dioxide (Si0 ₂ ) film
3: substrate
30: protective film coating device
4: grinding device
5: grinding unit
52: spindle unit
522: rotating spindle
525: Grinding Wheel
527: Grinding Stone
6: grinding feed means
7: Chuck Table Mechanism
72: Chuck Table Support Mechanism
725, 726: vertical position adjusting means
73: Chuck Table
731: Chuck Table Body
732: adsorption holding chuck
732a: holding surface
76: chuck table mechanism moving means
8: height position measuring means
9: control means
11: first cassette
12: second cassette
13: temporary mounting means of the workpiece
14: spinner cleaning means
15: workpiece conveyance means
16: the workpiece import means
17: means for carrying out the workpiece

Claims (2)

A wafer processing method in which electrodes connected to bonding pads respectively provided on a plurality of devices formed on a surface of a substrate form a wafer having a predetermined thickness embedded in the substrate,
A liquid resin coating step of coating the liquid resin on the surface of the substrate by dropping and rotating the liquid resin on the surface of the substrate for protecting the surface of the substrate;
A substrate bonding step of bonding the surface of the substrate to the surface of the substrate coated with a liquid resin through a liquid resin;
A height position measurement step of measuring a height position from the substrate on the back surface of the substrate on which the surface of the substrate is bonded through a liquid resin;
A wafer holding step of arranging the substrate side bonded to the surface of the substrate on a chuck table of a grinding apparatus, exposing the back surface of the substrate and holding the substrate on the chuck table;
The grinding surface of the grinding wheel is brought into contact with the rear surface of the substrate of the wafer while the grinding wheel is rotated to rotate the grinding wheel to the rear surface of the substrate of the wafer held on the chuck table. Includes the back grinding process,
Before performing the said back grinding process, the said board | substrate based on the height position from the said substrate in the back surface of the said board | substrate with which the surface of the said substrate measured by the said height position measuring process was bonded through the liquid resin. A slope from the outer circumference side to the center side on the back surface of the surface is determined, and a face state adjustment step of adjusting the facing state of the holding surface of the chuck table and the grinding surface of the grinding wheel in response to the slope is performed. Wafer processing method. A wafer processing method in which electrodes connected to bonding pads respectively provided on a plurality of devices formed on a surface of a substrate form a wafer having a predetermined thickness embedded in the substrate,
A liquid resin coating step of coating the liquid resin on the surface of the substrate by dropping and rotating the liquid resin on the surface of the substrate for protecting the surface of the substrate;
A substrate bonding step of bonding the surface of the substrate to the surface of the substrate coated with a liquid resin through a liquid resin;
A height position measurement step of measuring a height position from the substrate on the rear end surface of the back surface of the electrode embedded in the substrate on which the surface of the substrate is bonded through a liquid resin;
A wafer holding step of arranging the substrate side bonded to the surface of the substrate on a chuck table of a grinding apparatus, exposing the back surface of the substrate and holding the substrate on the chuck table;
The grinding surface of the grinding wheel is brought into contact with the rear surface of the substrate of the wafer while the grinding wheel is rotated to rotate the grinding wheel to the rear surface of the substrate of the wafer held on the chuck table. Includes the back grinding process,
Before performing the said back grinding process, the outer peripheral side in the back side end surface of an electrode based on the height position from the said substrate of the back side end surface in the said electrode measured by the said height position measuring process. And a slope from the center to the center side, and a face state adjustment step of adjusting the face state of the holding surface of the chuck table and the grinding surface of the grinding wheel in response to the slope.

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