JP2004228133A - Dividing method of semiconductor wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a semiconductor wafer from being damaged by facilitating the treatment of the semiconductor wafer which is formed thinner and hence its rigidity is lowered, when it is divided into individual chips. <P>SOLUTION: When the semiconductor wafer W including a plurality of circuits formed on the surface thereof is divided into chips of the individual circuits, the surface of the semiconductor wafer W is adapted to face the upper surface of a first support substrate 11 for supporting the semiconductor wafer W, and the semiconductor wafer W and the first support substrate 11 are integrated via an adhesive 10. The semiconductor wafer is polished over its rear surface in its state integrated with the first support substrate 11, and the rear surface of the semiconductor wafer W is adapted to face the upper surface of a second support substrate, and the semiconductor wafer and the second support substrate are integrated via an adhesive. The first support substrate 11 is exfoliated, the semiconductor wafer W is transferred onto the second support substrate in its state exposed over its surface, and the integrated semiconductor wafer W is divided into individual chips. Since the semiconductor wafer W is supported on the first support substrate or the second support substrate at all times, it is prevented from being damaged. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of polishing a back surface of a semiconductor wafer and dividing the semiconductor wafer into individual semiconductor chips.
[0002]
[Prior art]
A semiconductor wafer on which circuits such as ICs and LSIs are formed on the front surface is polished on the back surface to be formed to a predetermined thickness, and then divided into individual semiconductor chips by a dividing device such as a dicing device.
[0003]
When polishing the back surface of the semiconductor wafer, a protective tape is adhered to the front surface of the semiconductor wafer in order to prevent the circuit on the front surface from being damaged. Further, when dividing the polished semiconductor wafer into individual semiconductor chips, the front side where the streets are formed is exposed, the back side is attached to a dicing tape, and the semiconductor wafer is transferred and integrated with the dicing frame ( See, for example, Patent Document 1.
[0004]
[Patent Document 1]
JP-A-10-284449 (page 10, FIG. 9)
[0005]
[Problems to be solved by the invention]
However, in recent years, in order to reduce the size and weight of various electronic devices, it has been necessary to grind a semiconductor wafer to an extremely thin thickness of 100 μm or less and 50 μm or less. If the grinding is performed to such a degree, there is a problem that the rigidity of the semiconductor wafer is significantly reduced and handling becomes difficult. In particular, when transferring the semiconductor wafer from the protective tape to the dicing tape, there is a problem that the semiconductor wafer may be broken or damaged.
[0006]
Further, even when the semiconductor wafer is transferred from the protective tape to the dicing tape, there is also a problem that the dicing tape sags and the semiconductor wafer is broken.
[0007]
Therefore, when dividing a semiconductor wafer which is formed thin and has low rigidity into individual semiconductor chips, there is a problem in facilitating handling and preventing damage such as cracking of the semiconductor wafer.
[0008]
[Means for Solving the Problems]
As a specific means for solving the above problems, the present invention is a method for dividing a semiconductor wafer into a plurality of semiconductor chips for each circuit, the semiconductor wafer having a plurality of circuits formed on the surface, the method for supporting a semiconductor wafer A first integration step of integrating the semiconductor wafer and the first support substrate via an adhesive with the surface of the semiconductor wafer facing the upper surface of the first support substrate to be integrated with the first support substrate A polishing step of polishing the back surface of the semiconductor wafer in a state where the semiconductor wafer and the second support substrate face each other via an adhesive with the back surface of the semiconductor wafer facing the upper surface of the second support substrate supporting the semiconductor wafer. A second integration step of integrating the first support substrate from the surface of the semiconductor wafer, and exposing the surface of the semiconductor wafer to a semiconductor wafer on the second support substrate. A sorting step of transferring, and provides a method of dividing a semiconductor wafer composed of a dividing step of dividing the semiconductor wafer becomes a second support substrate integrally into individual semiconductor chips.
[0009]
In the method of dividing a semiconductor wafer, a pickup step of picking up semiconductor chips from a second support substrate is performed after the division step, the adhesive is a double-sided tape, and the adhesive is adhered by an external stimulus. That the force is reduced, of the double-sided tape, at least the side on which the semiconductor wafer is adhered is that the adhesive force is reduced by an external stimulus, before or after the second integration step, the first support To give an external stimulus to the adhesive interposed between the substrate and the semiconductor wafer, to reduce the adhesive force of the adhesive, in the pickup process, before picking up the semiconductor chip, the second support substrate and the semiconductor wafer Giving an external stimulus to the adhesive interposed between them to reduce the adhesive strength of the adhesive, the first support substrate and the second support substrate are made of synthetic resin, metal, Scan, the additional requirements to be formed by one of ceramics.
[0010]
According to the semiconductor wafer dividing method configured as described above, the polishing step, the dividing step, and the pickup step are performed in a state where the semiconductor wafer is supported on the first support substrate or the second support substrate. Handling is extremely easy even when the wafer becomes thin.
[0011]
In addition, when the process is shifted from the polishing process to the dividing process, the tape is not replaced, so that damage to the semiconductor wafer at the time of the replacement and after the replacement can be prevented.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
An example of an embodiment of the present invention will be described with reference to the drawings. The semiconductor wafer W shown in FIG. 1 is an example of a semiconductor wafer divided according to the present invention, and has a configuration in which a plurality of circuits are formed on the surface by being divided by streets S. It is divided into individual semiconductor chips C by cutting or the like.
[0013]
The semiconductor wafer W is turned upside down, and the surface of the semiconductor wafer W faces the upper surface of the first support substrate 11 as shown in FIG. (First integration step). Here, the double-sided tape 10 is an example of an adhesive, and for example, a liquid resin or the like can also be used.
[0014]
The first support substrate 11 is made of synthetic resin, glass, ceramics, metal, or the like, and has a rigidity that does not bend. The thickness of the support substrate 11 is 0.5 mm to 1.5 mm when formed of glass or ceramics, 0.3 mm to 1.0 mm when formed of metal (for example, stainless steel), and synthetic resin (for example, PET). When it is formed by, the thickness is preferably 0.1 mm to 0.5 mm.
[0015]
As shown in FIG. 3, the back surface of the semiconductor wafer W integrated with the first support substrate 11 is polished by, for example, the polishing apparatus 20 shown in FIG.
[0016]
In the polishing apparatus 20, a wall 22 is provided upright from an end of a base 21, and a pair of rails 23 is vertically disposed on an inner surface of the wall 22. The polishing means 25 attached to the support plate 24 moves up and down as the support plate 24 moves up and down. A turntable 26 is rotatably disposed on the base 21. The turntable 26 rotatably supports a chuck table 27 for holding a semiconductor wafer.
[0017]
In the polishing means 25, a mounter 29 is mounted on a tip of a spindle 28 having a vertical axis, a polishing wheel 30 is further mounted below the mounter 29, and a polishing wheel 31 is fixed to a lower surface of the polishing wheel 30. The polishing grindstone 31 rotates with the rotation of the spindle 28.
[0018]
When grinding the back surface of the semiconductor wafer W using the polishing apparatus 20, the semiconductor wafer W integrated with the first support substrate 11 is held on the chuck table 27 so that the back surface is exposed, and The polishing means 25 is moved down while the chuck table 27 is rotated and the spindle 28 is rotated. Then, the polishing wheel 30 rotates with the rotation of the spindle 28, and the rotating polishing grindstone 31 comes into contact with the back surface of the semiconductor wafer W to apply a pressing force, whereby the back surface is polished by the polishing grindstone 31 ( Polishing step).
[0019]
Then, as shown in FIG. 5, after the semiconductor wafer W is formed to a desired thickness (for example, 100 μm or less, 50 μm or less), the semiconductor wafer W is turned upside down while being integrated with the first support substrate 11. As shown in FIG. 6, the back surface of the semiconductor wafer W faces the upper surface of the second support substrate 40, and the semiconductor wafer W and the second support substrate 40 are integrated via the double-sided tape 41. (The second integration step).
[0020]
Here, the second support substrate 40 is made of synthetic resin, glass, ceramics, metal, or the like, and has a rigidity that does not bend. The thickness of the support substrate 11 is 0.5 mm to 1.5 mm when formed of glass or ceramics, 0.3 mm to 1.0 mm when formed of metal (for example, stainless steel), and synthetic resin (for example, PET). When it is formed by, the thickness is preferably 0.1 mm to 0.5 mm.
[0021]
Next, when the first support substrate 11 attached to the surface of the semiconductor wafer W is peeled off in the first integration step, the surface on which the circuit is formed is exposed as shown in FIG. Replacement process).
[0022]
In the case where at least the pressure-sensitive adhesive on the surface of the double-sided tape 10 to which the semiconductor wafer W is adhered is formed of a type in which the adhesive force is reduced by an external stimulus, the second integration step If an external stimulus is given to the double-sided tape 10 before or after, the first support substrate 11 can be easily peeled off in the transfer step. For example, when the external stimulus is ultraviolet light, the first support substrate 11 is formed of glass or PET that transmits ultraviolet light, and at least the surface of the double-sided tape 10 on which the semiconductor wafer W is adhered. The adhesive is of a type that can reduce the adhesive strength by irradiation with ultraviolet rays.
[0023]
In this manner, the semiconductor wafer W having the second support substrate 40 attached to the back surface and the front surface exposed is diced in this state by, for example, a cutting device 50 shown in FIG. 9 and divided into individual semiconductor chips. You.
[0024]
In the cutting device 50, as shown in FIG. 8, a plurality of semiconductor wafers W integrated with the second support substrate 40 are stored in a cassette 51. Then, the semiconductor wafer W is conveyed one by one to the temporary storage area 53 by the carrying-in / out means 52, sucked by the carrying means 54, and conveyed to the chuck table 55 by the turning movement thereof, and is suctioned in a state where the back surface of the semiconductor wafer W faces upward and is exposed. Will be retained.
[0025]
When the semiconductor wafer W integrated with the second support substrate 40 is sucked and held by the chuck table 55, the chuck table 55 moves in the + X direction and is positioned immediately below the imaging means 56.
[0026]
The imaging means 56 images the surface of the semiconductor wafer W and detects streets S (see FIG. 1) formed on the surface to be cut by processing such as pattern matching by the alignment means 56a. Then, after alignment of the cutting blade 57 having the same Y coordinate with the imaging means 56 and the detected street in the Y-axis direction is performed, the chuck table 55 further moves in the + X direction, and the cutting blade 57 rotating at a high speed rotates. Under the action, the detected street is cut.
[0027]
When the chuck table 55 is reciprocated in the X-axis direction while indexing and feeding the cutting blades 57 in the Y-axis direction at street intervals, all streets in the same direction are cut.
[0028]
Further, when the chuck table 55 is further rotated by 90 degrees and the same cutting is performed as described above, as shown in FIG. 10, all the streets are cut vertically and horizontally to form individual semiconductor chips C (see FIG. 1). It is divided (dividing step). At this time, the individual semiconductor chips C are held on the second support substrate 40 while maintaining the shape of the semiconductor wafer W.
[0029]
Note that, in the above example, the case where the semiconductor chip is divided into semiconductor chips by cutting has been described. However, it is also possible to divide the street into individual semiconductor chips by irradiating a laser beam with a laser cutting device.
[0030]
As shown in FIG. 10, after the semiconductor wafer W is divided into individual semiconductor chips C while maintaining its shape, as shown in FIG. Are picked up one by one from the supporting substrate 40 (pickup step).
[0031]
Here, when at least the surface of the double-sided tape 41 shown in FIG. 6 to which the semiconductor wafer W is adhered is a type of adhesive whose adhesive force is reduced by an external stimulus, the adhesive is If the pick-up is performed after the adhesive force is reduced by giving a target stimulus, the pick-up can be performed easily and smoothly. In the illustrated example, the external stimulus is ultraviolet light, and the second support substrate 40 is formed of glass and PET that transmit ultraviolet light, and at least one of the double-sided tapes 41 to which the semiconductor wafer W is adhered. The pressure-sensitive adhesive on the surface is of a type that can reduce the adhesive strength by irradiation with ultraviolet rays.
[0032]
When the first integration step, the polishing step, the second integration step, the transfer step, and the division step are performed as described above, the semiconductor wafer is peeled off from the support substrate and adhered to the dicing tape as in the related art. Since the polishing step, the dividing step, and the pickup step are performed while being supported by the first support substrate 11 or the second support substrate 40, the semiconductor wafer W thinned by polishing can be easily handled. Therefore, it is possible to prevent the semiconductor wafer W from being cracked or chipped.
[0033]
In the above embodiment, the case where the outer diameter of the semiconductor wafer W is equal to the outer diameter of the first support substrate 11 has been described as an example, but the first support substrate 11a shown in FIG. When a support substrate having a larger outer diameter than the semiconductor wafer W is used, as shown in FIG. 13, in a polishing step, a stylus-type thickness measuring device 72 having styluses 70 and 71 is used. By bringing one stylus 70 into contact with the upper surface of the first support substrate 11a and making the other stylus 71 into contact with the back surface of the semiconductor wafer W, the stylus 70 is moved based on the difference in the height position between the two styluses. The polishing can be performed while measuring the thickness of the semiconductor wafer W. In addition, since only the first support substrate 11 can be held during transportation, there is no possibility that the semiconductor wafer W will be damaged.
[0034]
【The invention's effect】
As described above, according to the method for dividing a semiconductor wafer according to the present invention, the polishing step, the dividing step, and the pickup step are performed while the semiconductor wafer is supported on the first support substrate or the second support substrate. Therefore, even if the semiconductor wafer becomes thin, handling is extremely easy, and damage to the semiconductor wafer can be prevented.
[0035]
Also, when the process is shifted from the polishing process to the dividing process, the semiconductor wafer is not replaced at the time of the replacement, and damage to the semiconductor wafer at the time of the replacement and after the replacement can be prevented, and the safety is increased.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of a semiconductor wafer.
FIG. 2 is a perspective view showing a first integration step.
FIG. 3 is a perspective view showing a semiconductor wafer integrated with a first support substrate.
FIG. 4 is a perspective view showing an example of a polishing apparatus.
FIG. 5 is a perspective view showing a semiconductor wafer integrated with a first support substrate after polishing.
FIG. 6 is a perspective view showing a second integration step.
FIG. 7 is a perspective view showing a semiconductor wafer integrated with a first support substrate and a second support substrate.
FIG. 8 is a perspective view showing a semiconductor wafer integrated with a second support substrate.
FIG. 9 is a perspective view showing an example of a cutting device.
FIG. 10 is a perspective view showing a semiconductor wafer divided into individual semiconductor chips and integrated with a second support substrate.
FIG. 11 is a perspective view illustrating an example of a pickup step.
FIG. 12 is a perspective view showing a second example of the first support substrate.
FIG. 13 is a front view showing how the thickness of the semiconductor wafer is measured in the polishing step.
[Explanation of symbols]
W ... Semiconductor wafer S ... Street C ... Semiconductor chip 10 ... Double-sided tape (adhesive) 11 ... First support substrate 20 ... Polishing device 21 ... Base 22 ... Wall 23 ... Rail 24 ... Support plate 25 ... Polishing means 26 ... turntable 27 ... chuck table 28 ... spindle 29 ... mounter 30 ... polishing wheel 31 ... polishing wheel 40 ... second support substrate 41 ... double-sided tape (adhesive)
Reference Signs List 50 cutting apparatus 51 cassette 52 loading / unloading means 53 temporary placement area 54 transport means 55 chuck table 56 imaging means 56a alignment means 57 cutting blade 60 suction collets 70 and 71 stylus 72 thickness Measuring instrument

Claims (8)

A method of dividing a semiconductor wafer that divides a semiconductor wafer having a plurality of circuits formed on a surface into semiconductor chips for each circuit,
A first integration step of integrating the semiconductor wafer and the first support substrate via an adhesive with the surface of the semiconductor wafer facing the upper surface of the first support substrate supporting the semiconductor wafer,
A polishing step of polishing the back surface of the semiconductor wafer integrated with the first support substrate,
A second integration step of integrating the semiconductor wafer and the second support substrate via an adhesive with the back surface of the semiconductor wafer facing the upper surface of the second support substrate supporting the semiconductor wafer,
A transfer step of separating the first support substrate from the surface of the semiconductor wafer and exposing the surface of the semiconductor wafer to transfer the semiconductor wafer to the second support substrate,
A dividing step of dividing the semiconductor wafer integrated with the second support substrate into individual semiconductor chips,
A method for dividing a semiconductor wafer comprising: 2. The method according to claim 1, wherein after the dividing step, a pickup step of picking up semiconductor chips from the second support substrate is performed. 3. The method for dividing a semiconductor wafer according to claim 1, wherein the adhesive is a double-sided tape. 4. The method for dividing a semiconductor wafer according to claim 1, wherein the adhesive has a reduced adhesive strength due to an external stimulus. The method for dividing a semiconductor wafer according to claim 4, wherein at least the surface of the double-sided tape on which the semiconductor wafer is adhered has a reduced adhesive strength due to an external stimulus. The adhesive according to claim 4 or 5, wherein an external stimulus is applied to the adhesive interposed between the first support substrate and the semiconductor wafer before or after the second integration step to reduce the adhesive strength of the adhesive. Semiconductor wafer dividing method. In the pickup step, before picking up the semiconductor chip, an external stimulus is applied to the adhesive interposed between the second support substrate and the semiconductor wafer to reduce the adhesive force of the adhesive. 7. The method for dividing a semiconductor wafer according to item 6. The semiconductor wafer division according to claim 1, 2, 3, 4, 5, 6, or 7, wherein the first support substrate and the second support substrate are formed of any one of synthetic resin, metal, glass, and ceramics. Method.

Images