TW202405928A - Wafer handling methods and support tables - Google Patents

Abstract

[Problem] Provide a wafer processing method that can solve the problem of wafer damage when peeling off the protective film. [Solution] A method of processing a wafer, which has a component area on the front surface in which a plurality of components are formed and a remaining area surrounding the component area. The wafer processing method at least includes: a protective film Provided is a step of arranging a protective film on the front side of the wafer; a back grinding step of holding the protective film side on a chuck table and grinding the back side of the wafer to form a recess in an area corresponding to the component area, and A convex ring is formed in an area corresponding to the remaining area of the outer periphery; and a protective film peeling step that peels off the protective film from the front surface of the wafer, and a support table is used in the protective film peeling step. The support is formed in a recessed portion on the back side of the wafer.

Description

Wafer handling methods and support tables

The present invention relates to a wafer processing method and a support table used in the wafer processing method. The wafer has a device area formed with a plurality of devices on the front side and an outer peripheral remaining area surrounding the device area.

On the front side of the wafer, a device area including a plurality of components such as ICs and LSIs divided by planned division lines and a remaining area around the outer circumference of the device area are formed after the back surface is ground by a grinding device and formed into a required thickness. , divided into individual component wafers by a cutting device, and used in electronic devices such as mobile phones and personal computers.

In addition, as a method for grinding the back surface of a wafer, the applicant of this case has proposed a technology in which the back surface area corresponding to the device area is not damaged during the transportation and back surface processing of the thinned wafer. It is ground to a required thickness, and a convex ring as a reinforcing portion is formed in the back area corresponding to the remaining outer peripheral area (see Patent Document 1). [Known technical documents] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2007-019461

[Problem to be solved by the invention] In the technology described in the above-mentioned Patent Document 1, when grinding the back surface of the wafer, a protective film is laid to protect the components formed on the front surface of the wafer. Then, after the area corresponding to the device area on the back side of the wafer is thinned by grinding processing, when the back side is subjected to back processing such as covering the back side with a metal film, there is a thermal process associated with the back processing. Due to the handling, it is necessary to peel off the protective film from the front side of the wafer. However, as mentioned above, the area of the wafer corresponding to the device area has been thinned by grinding. Even if a convex ring as a reinforcing portion is formed in the back area of the remaining outer peripheral area, the protective film will not be removed when the protective film is peeled off. This may cause damage to the component area of the wafer.

The present invention was completed in view of the above facts, and its main technical subject is to provide a wafer processing method and a support table used in the wafer processing method, which can solve the problem that the wafer will be damaged when the protective film is peeled off. problem.

[Technical means to solve the problem] In order to solve the above-mentioned main technical problems, according to the present invention, there is provided a processing method of a wafer, which has an element area on the front surface in which a plurality of elements are formed and a peripheral remaining area surrounding the element area. The wafer processing method is provided. At least it has: a protective film disposing step, which disposes the protective film on the front side of the wafer; a back grinding step, which holds the protective film side on the chuck table and grinds the back side of the wafer, and in the component area A concave portion is formed in the corresponding area, and a convex ring is formed in the area corresponding to the remaining peripheral area; and a protective film peeling step that peels off the protective film from the front side of the wafer, and is used in the protective film peeling step A support platform supports a recess formed on the back surface of the wafer.

Moreover, according to the present invention, there is provided a support table, which is a support table used in the above-mentioned wafer processing method, and is composed of the following: a support part whose size corresponds to a recess formed on the back surface of the wafer; and a step portion corresponding to the convex ring formed on the back surface of the wafer and formed on the outer periphery of the support portion.

It is preferable to lay resin on the upper surface of the support platform. Furthermore, it is preferable to form a suction part on the support table, and the suction part suctions the recessed part holding the wafer.

[Invention effect] The wafer processing method of the present invention is a processing method for a wafer having a device area formed with a plurality of devices on the front side and a remaining area surrounding the outer periphery of the device area, and at least includes: a step of disposing a protective adhesive film, which will protect the wafer. The adhesive film is disposed on the front side of the wafer; the backside grinding step holds the protective adhesive film side on the chuck table and grinds the backside of the wafer, forming a recess in the area corresponding to the component area, and in the remaining area corresponding to the outer periphery The area forms a convex ring; and a protective film peeling step, which peels off the protective film from the front side of the wafer, and a support table is used in the protective film peeling step, and the support table supports the surface formed on the wafer. The concave portion on the back side, therefore, prevents excessive force from acting on the component area when peeling off the protective film from the front side of the wafer, thus solving the problem of wafer damage.

Furthermore, the support table of the present invention is composed of the following: a support part whose size corresponds to a concave part formed on the back surface of the wafer; and a step part which corresponds to a convex ring formed on the back surface of the wafer. And is formed on the outer periphery of the support part. Therefore, when peeling off the protective film from the front side of the wafer, by using this support platform, excessive force is prevented from acting on the component area, which helps to solve the problem of wafer damage. .

Hereinafter, embodiments of a wafer processing method based on the present invention and a support table used in the processing method will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a wafer 10 to be processed in this embodiment and a protective film T1 disposed on the front surface 10 a of the wafer 10 . The wafer 10 of this embodiment includes a semiconductor substrate made of silicon (Si) with a diameter of 100 mm and a thickness of 700 μm, and is provided with an element region 11 a on the front surface 10 a side of the semiconductor substrate, which is divided by planned division lines. 13 is divided into a plurality of components 12; and a peripheral remaining area 11b surrounds the component area 11a. The front surface 10 a of the wafer 10 shows a dotted chain line 11 that distinguishes the device area 11 a and the peripheral remaining area 11 b. However, the dotted chain line 11 is a virtual line added for convenience of explanation and is not arranged on the actual wafer 10 The front side of 10a. If the above-mentioned wafer 10 has been prepared, as shown in the upper part of Figure 1, a protective film disposing step is performed on the front surface 10a of the wafer 10. The protective film disposing step is to adhere the protective film T1 and integrate it. change. Next, the wafer 10 integrated with the protective adhesive film T1 is turned over. As shown in the lower part of FIG. 1 , the back surface 10 b of the wafer 10 is exposed above.

Next, for example, the back surface 10b is ground using the grinding device 2 shown in FIG. 2 (only part of it is shown). This grinding device 2 includes a rotatable chuck table 20 that holds the wafer 10 and a grinding means 21 that performs grinding processing on the wafer 10 . The grinding means 21 is provided with: a spindle 22 that can rotate and move up and down; a grinding wheel 23 that is mounted on the front end of the spindle 22 and rotates as the spindle 22 rotates; and a grinding stone 24 that is annularly fixed to the grinding wheel. The lower surface of wheel 23.

The protective member T1 side of the wafer 10 is held on the chuck table 20 so that the back surface 10 b of the wafer 10 faces the grinding stone 24 . Then, the main shaft 22 is rotated in the direction indicated by the arrow R1, and the grinding wheel 23 rotating together with the main shaft 22 is lowered in the direction indicated by the arrow R2. At this time, the chuck table 20 is first rotated in the direction shown by arrow R3, and then the grinding stone 24 is brought into contact with the back surface 10b of the wafer 10. The grinding stone 24 is set to contact the back surface area of the back surface 10b corresponding to the element area 11b of the front surface 10a, and not to grind the other parts, that is, the area corresponding to the outer peripheral remaining area 11a. Thereby, as shown in the upper part of FIG. 2( b ) and FIG. 3 , the recess 14 is formed in the central area of the back surface 10 b corresponding to the ground element area 11 b, and in the outer peripheral remaining area 11 a corresponding to the outer peripheral side. The area forms a convex ring 15 having a step between the bottom surfaces of the recess 14 . As a result of performing the back grinding step as described above, the thickness of the pre-processed wafer 10 (700 μm) remains unchanged in the ring 15 portion, while the thickness of the recessed portion 14 is thinned to about 30 μm, for example. In addition, the dimensions of the cross section shown in Fig. 2(b) are not based on actual dimensional ratios.

After the above-mentioned back surface grinding step has been performed, a support stand 30 as shown in the lower section of FIG. 3 is prepared to be used when performing the protective film peeling step described later. The support table 30 of this embodiment is composed of the following: a support portion 34 whose size corresponds to the recessed portion 14 formed on the back surface 10b of the wafer 10 through the above-described back surface grinding step; and a step portion 32 whose size corresponds to The convex ring 15 formed on the back surface 10 b of the wafer 10 corresponds to and is formed on the outer periphery of the support portion 34 . The support portion 34 has a substantially circular shape corresponding to the recessed portion 14 described above, and the upper surface 34 a of the support portion 34 is flat. The diameter P of the support portion 34 is slightly smaller than the inner diameter of the recessed portion 14 , preferably about 1 to 2 mm smaller, and the height of the upper surface 34 a of the support portion 34 is higher than the front surface 32 a of the step portion 32 . The size is formed to be equal to or larger than the depth of the recess 14 , for example, about 50 μm.

If the above support table 30 has been prepared, as shown in FIG. 3 , turn the wafer 10 so that the side with the recess 14 faces downward, face the side with the protective adhesive film T1 upward, and turn the recess 14 It is positioned and placed on the support portion 34 of the support platform 30 . As described above, the diameter of the support portion 34 is set smaller than the size of the recessed portion 14 , and the height of the upper surface 34 a of the support portion 34 with respect to the front surface 32 of the step portion 32 is formed to be equal to or equal to the depth of the recessed portion 14 . The size is greater than the depth, so the support part 34 will enter the recess 14 of the wafer 10 , and the bottom of the recess 14 is supported by the upper surface 34 a of the support part 34 .

As described above, when the recessed portion 14 of the wafer 10 is supported by the supporting portion 34 of the supporting table 30, as shown in FIG. 4, the operator presses the side of the wafer 10 with one hand H1 and presses the other hand H1 with the other hand. Hold the outer peripheral end of the protective film T1 with only hand H2, and perform a protective film peeling step of peeling off the front surface 10a of the wafer 10. In addition, in FIG. 4 , for convenience of explanation, the sequence of peeling off the protective film T1 by the operator's hands is shown, but the protective film peeling step of the present invention is not limited to the manual operation by the operator. Implementation can also be implemented by automated machinery.

The above concludes the wafer processing method of this embodiment. According to the above embodiment, since the recessed portion 14 of the wafer 10 presses the element region 11 b supported from below by the supporting portion 34 of the supporting table 30 from above, the protective film T1 is peeled off from the front surface 10 a of the wafer 10 . This avoids applying excessive force to the component area, thereby solving the problem of damage to the wafer 10 .

The above-mentioned supporting platform 30 can be manufactured, for example, as shown in FIG. 5 . In Fig. 5(a), a base material 30' used for manufacturing the support stand 30 is shown. The base material 30' is a cylindrical member made of silicon (Si), for example. When making the above-mentioned support stand 30 from the base material 30', the grinding device 40 shown in Fig. 5(a) is used (only part of it is shown). The grinding device 40 includes a rotating spindle 42; a disc-shaped grinding stone 43 fixed to the front end of the rotating spindle 42; and a spindle housing 44 that rotatably supports the rotating spindle 42, and the rotating spindle 42 is The grinding device 40 is rotationally driven by a spindle motor (not shown) disposed on the rear end side of the spindle housing 44. The grinding device 40 is provided with a moving means (not shown) that moves the spindle housing 44 and holds the mother. The chuck table (not shown) of the material 30' moves relatively. The grinding grindstone 43 is, for example, a grinding grinding stone made of nickel-plated fixed diamond abrasive grains, with a diameter of 60 mm and a thickness of 10 mm. The outer peripheral end of the grinding grinding stone 43 is composed of a slightly flat surface.

When the support table 30 is manufactured from the base material 30', the base material 30' is held on the chuck table and appropriately aligned, as shown in Fig. 5(a), so that the annular shape of the predetermined support portion 34 is contacted from the outside. The grinding stone 43 is positioned on the upper surface of the area where the above-mentioned step portion 32 is formed in the base material 30' in the form of a line 34b. Next, the grinding stone 43 is rotated in the direction indicated by the arrow R4, and the base material 30' is rotated in the direction indicated by the arrow R5. After the base material 30' is rotated, the grinding stone 43 is lowered at a speed of, for example, 1 μm/second to grind the outer peripheral region of the base material 30' from the upper surface, and then lowers to the position where the above-mentioned step portion 32 is formed. By proceeding in this manner, the support base 30 having the support portion 34 and the step portion 32 as described with reference to FIG. 3 is formed.

In addition, the supporting platform of the present invention is not limited to the above-mentioned supporting platform 30. For example, as shown in FIG. 5( b ), when supporting the wafer 10 , the recess 14 on the back surface 10 b side of the wafer 10 may be formed on the upper surface of the support part 34 to be in contact with it, and may be laid with the purpose of protecting the wafer 10 . Resin that becomes a buffer material (for example, resin sheet T2). The sheet T2 is, for example, a resin sheet formed to have the same diameter as the support portion 34, and is preferably a thermocompression bonding sheet. The thermocompression bonding sheet may be selected from, for example, a polyolefin-based sheet or a polyester-based sheet. When a polyolefin sheet is selected as the sheet T2 and laid on the support part 34, the sheet T2 is placed on the support part 34, and the sheet T2 is heated to near the melting point temperature, and a pressure bonding method (not shown) is used. Press and attach using a roller or the like. By arranging the sheet T2 on the support part 34 in this way, when the wafer 10 is supported by the support part 34, the sheet T2 functions as a buffer material, thereby more reliably preventing the protection described in FIG. 4 from being implemented. There is a problem that the wafer 10 will be damaged during the film peeling step. In addition, liquid resin may be dripped onto the support part 34 to form a solidified layer instead of the above-mentioned sheet T2, thereby functioning as the above-mentioned buffer material.

The supporting platform 30 is not limited to the above-mentioned method. As shown in FIG. 5( c ), a plurality of suction parts 35 for sucking and holding the wafer 10 may be formed on the support part 34 to which the sheet T2 is attached and the sheet T2 . Then, a suction means (not shown) is connected to the suction part 35 through the step part 32, and a negative pressure Vm is generated on the support part 34, so that the recessed part 14 is positioned on the support part 34 and the wafer 10 is suctioned and held. Thereby, when peeling off the protective adhesive film T1 from the front surface 10 a of the wafer 10 , the wafer 10 can be reliably attracted and fixed on the support table 30 , and the protective adhesive film T1 can be peeled off stably. In addition, the suction portion 35 is effective even when the sheet T2 is not attached, and helps to stably hold the wafer 10 .

The above-mentioned step of peeling off the protective film can be implemented by separately preparing the supporting platform 30 , or can be implemented by a peeling device configured to automatically perform the step of peeling off the above-mentioned protective film. Furthermore, it can also be implemented in other processing equipment.

2:Grinding device 20:Chuck table 22:Spindle 23:Grinding wheel 24: Grinding stone 10:wafer 10a: Front 10b: Back 11: One point chain line 11a: Peripheral remaining area 11b: component area 12:Component 13: Split scheduled line 14: concave part 15: Ring 30:Support platform 30’: base material 32: Step difference department 34: Support part 35:Suction hole 40:Grinding device 42:Rotating spindle 43: Grinding stone 44:Spindle housing T1: Protective film T2: thin slices

FIG. 1 is a perspective view of a wafer and a protective sheet processed by this embodiment. FIG. 2( a ) is a perspective view showing an embodiment of the back grinding step performed by the grinding device, and FIG. 2( b ) is an enlarged cross-sectional view of the wafer ground by the back grinding step. FIG. 3 is a perspective view showing a state in which the wafer is held on the support table. FIG. 4 is a perspective view showing an embodiment of the protective film peeling step. Figure 5(a) is a perspective view showing a state in which processing is performed to produce the support stand. Figure 5(b) is a perspective view showing a state in which resin is laid on the support portion of the support stand. Figure 5(c) is a perspective view showing the support stand. A perspective view of another embodiment.

10:wafer

10a: Front

10b: Back

11: One point chain line

11a: Peripheral remaining area

11b: component area

12:Component

14: concave part

15: Ring

30:Support platform

32: Step difference department

32a:front

34: Support part

34a: Upper surface

T1: Protective film

P: diameter

Claims (4)

A method of processing a wafer. The wafer has a component area formed with multiple components on the front side and a remaining area around the outer periphery of the component area. The wafer processing method at least includes: a protective film dispensing step, which will protect The adhesive film is disposed on the front side of the wafer; The backside grinding step is to hold the protective film side on the chuck table and grind the backside of the wafer to form a concave portion in the area corresponding to the component area and to form a convex ring in the area corresponding to the remaining outer peripheral area. ;as well as a protective film stripping step, which peels off the protective film from the front side of the wafer, A support table is used in the protective film stripping step, and the support table supports the recess formed on the back side of the wafer. A support table that is used in the wafer processing method of claim 1 and is composed of: a support part whose size corresponds to a recess formed on the back surface of the wafer; and a step part, It corresponds to the convex ring formed on the back surface of the wafer and is formed on the outer periphery of the support part. The support platform of claim 2, wherein resin is laid on the upper surface of the support platform. The support table of claim 2, wherein an attraction part is formed on the support table, and the attraction part attracts and holds the concave part of the wafer.