Method for dicing semiconductor wafers

Abstract

A semiconductor wafer dividing method capable of reusing a dressing member and isotropically elongating a dicing tape is obtained. When a blade (28) is dressed for the purpose of improving the sharpness of the blade (28), the dressing member (16) is not completely cut off because the blade (28) passes through the upper portion of the dressing member (16). Therefore, the dressing member (16) used once in dressing the blade (28) can be reused. In addition, the dressing member (28) is not attached to the inner side of the first ring (14). Therefore, the dicing tape (10) can be isotropically elongated.

Description

Technical Field

[0001] This disclosure relates to a method for dicing semiconductor wafers. Background Technology

[0002] To separate semiconductor wafers into semiconductor chips, a dicing process and a spreading process are required. In the dicing process, the semiconductor wafer, adhered to dicing tape, is cut into a grid pattern using a blade, thus dividing it into multiple semiconductor chips. In the spreading process, the dicing tape is isotropically stretched to separate the semiconductor chips from each other. The semiconductor chips are then removed after these processes.

[0003] During the dicing process, chipping sometimes occurs. When cutting a semiconductor wafer, the metals, organic matter, etc., contained in the wafer can clog the cutting blade. This clog reduces the blade's sharpness. If a semiconductor wafer is cut with a blade whose sharpness has deteriorated, a gap will be created on the dicing line. This condition, where a gap is created, is called chipping.

[0004] To prevent chipping, blade dressing is an effective method. If a blade that has lost sharpness is dressed using a dressing component, its sharpness can be restored, thus preventing chipping.

[0005] Patent Document 1 discloses a method for cutting a semiconductor wafer after blade trimming by placing a trimming component near the wafer. In this method, the trimming component is attached to cutting tape near the semiconductor wafer. The blade is controlled to pass through the trimming component each time before cutting the semiconductor wafer. This method restores the blade's sharpness before cutting the semiconductor wafer.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-024135

[0007] However, the method disclosed in Patent Document 1 has the problem of not being able to reuse the trimming component. In this method, after the semiconductor wafer dicing process is completed, the trimming component remains adhered to the dicing tape. Therefore, during trimming, if the blade does not completely cut the trimming component, it is difficult to stretch the dicing tape isotropically, and the dicing tape cannot be properly extended. For proper extension, the trimming component must be cut, but if this is done, the cut trimming component cannot be reused. Summary of the Invention

[0008] This disclosure is made to solve the above-mentioned problems, and its purpose is to provide a method for dividing semiconductor wafers that allows for the reuse of trimming components and isotropic elongation of cutting tape.

[0009] The semiconductor wafer dicing method disclosed herein includes: an adhesive bonding step in which a first ring is positioned to surround the semiconductor wafer, a trimming member is positioned to the outside of the first ring, and a second ring is positioned to surround the first ring and the trimming member, wherein the semiconductor wafer, the first ring, the trimming member, and the second ring are bonded to a dicing tape; a dicing step in which, after the adhesive bonding step, until the dicing of the semiconductor wafer into a semiconductor chip is completed, the semiconductor wafer is cut multiple times by means of a blade; and a dicing tape cutting step in which, after the dicing step, the dicing tape is cut to the outside of the first ring such that the trimming member and the second ring are not included on the inside, wherein, in the dicing step, the blade passes over the trimming member, thereby trimming the blade.

[0010] According to the semiconductor wafer dicing method disclosed herein, the blade does not completely cut off the dicing component during dicing, and the dicing component is not attached to the inner side of the first ring, thus enabling the dicing component to be reused and the cutting tape to be isotropically elongated. Attached Figure Description

[0011] Figure 1 This is a top view of a cutting tape with a semiconductor wafer, a first ring, a trimming component, and a second ring attached in the semiconductor wafer dicing method according to Embodiment 1.

[0012] Figure 2 This is a cross-sectional view of a cutting tape with a semiconductor wafer, a first ring, a trimming component, and a second ring attached in the semiconductor wafer dicing method according to Embodiment 1.

[0013] Figure 3 This is a cross-sectional view of the state in which the cutting tape is set in the cutting apparatus in the semiconductor wafer dicing method according to Embodiment 1.

[0014] Figure 4 This is a cross-sectional view used to illustrate the cutting process in the semiconductor wafer dicing method according to Embodiment 1.

[0015] Figure 5 This is a top view of the semiconductor wafer after the cutting process in the semiconductor wafer dicing method according to Embodiment 1.

[0016] Figure 6 This is a top view of the semiconductor wafer, the first ring, and the cutting tape after the tape cutting process in the semiconductor wafer dicing method according to Embodiment 1.

[0017] Figure 7 This is a top view of a cutting tape with a semiconductor wafer, a first ring, a trimming component, and a second ring attached in the semiconductor wafer dicing method according to Embodiment 3.

[0018] Explanation of reference numerals in the attached figures

[0019] 10...Cutting tape; 12...Semiconductor wafer; 14...First ring; 16...Trimping component; 18...Second ring; 20...Semiconductor chip; 22...Cutting device; 24...Chuck table; 26...Clamp; 28...Blade. Detailed Implementation

[0020] Implementation Method 1

[0021] The semiconductor wafer dicing method according to Embodiment 1 will be described.

[0022] First, such as Figure 1 as well as Figure 2 As shown, a process of attaching a semiconductor wafer 12, a first ring 14, a trimming component 16, and a second ring 18 to a cutting tape 10 is performed. Figure 1 This is a picture of the cut tape 10 after the pasting process, viewed from above. Figure 2 yes Figure 1 A cross-sectional view (AA). In this process, the semiconductor wafer 12, the first ring 14, the trimming component 16, and the second ring 18 are attached to the cutting tape 10 such that the first ring 14 is positioned to surround the semiconductor wafer 12, the trimming component 16 is positioned outside the first ring 14, and the second ring 18 is positioned to surround the first ring 14 and the trimming component 16. The order of attachment is not particularly limited.

[0023] Dressing component 16 is formed by fixing green diamond abrasive grains, approximately 1 mm thick, made of silicon carbide, to a resin adhesive made of phenolic resin with added filler. Alternatively, silicon plates or similar materials can also be used. Although dressing component 16... Figure 1 The blades are positioned to the left and below the semiconductor wafer 12, but at least two of them can be positioned such that the angle between them from the center of the semiconductor wafer 12 toward the trimming member 16 is 90 degrees. In this way, when the semiconductor wafer 12 is cut in the cutting process described later in either of the two directions, the trimming of the blade 28 and the cutting of the semiconductor wafer 12 can be carried out smoothly.

[0024] Next, as Figure 3 As shown, Figure 1 The cutting tape 10 is placed in the cutting device 22. The cutting device 22 includes a chuck table 24, a clamp 26, and a blade 28. Here, the cutting tape 10 is placed on the chuck table 24, and the second ring 18 is fixed by the clamp 26. In addition, the cutting tape 10 is vacuum-adsorbed by a porous material used on the upper surface of the chuck table 24.

[0025] Next, as Figure 4 As shown, a cutting process is performed to trim the blade 28 and cut the semiconductor wafer 12. The movement of the blade 28 is indicated by dashed lines. The direction of rotation of the blade 28 is indicated by arrows. In this process, firstly, the blade 28 passes over the upper part of the trimming member 16, thereby trimming the blade 28. At this time, the blade 28 only passes over the upper part of the trimming member 16, not its lower end. Therefore, the blade 28 does not cut the trimming member 16. Next, the blade 28 passes over the first ring 14. Then, the blade 28 cuts the semiconductor wafer 12. However, it does not cut the cutting tape 10. The trimming of the blade 28 and the cutting of the semiconductor wafer 12 are repeatedly performed by shifting the position of the blade 28 in a direction perpendicular to the cutting direction. When cutting in one direction is completed, the cutting direction is rotated 90 degrees, and the same process is repeated. In this way, in the cutting process, until as Figure 5 The semiconductor wafer 12 is cut into the semiconductor chip 20 multiple times by the blade 28 until the cutting is completed. Furthermore, the rotation direction of the blade 28 can be determined according to the material of the semiconductor wafer 12, or it can be the opposite direction.

[0026] The blade 28 is positioned differently in the height direction when passing above the trimming member 16, above the first ring 14, and when cutting the semiconductor wafer 12. The heights of the lower end of the blade 28 when passing above the trimming member 16, above the first ring 14, and when cutting the semiconductor wafer 12 are respectively defined as Z1, Z2, and Z3. The reference for the height is the upper surface of the chuck stage 24. The values ​​of Z1 to Z3 can be appropriately determined based on conditions such as the thickness of the trimming member 16, the first ring 14, and the semiconductor wafer 12. The blade 28 moves while changing its height according to the location and based on the values ​​of Z1 to Z3, following a program stored in an internal or external storage device (not shown) of the cutting apparatus 22.

[0027] Next, the tape cutting process of cutting the tape 10 is carried out. In this process, the tape 10 is cut on the outside of the first ring 14 in such a way that the trimming part 16 and the second ring 18 are not included on the inside. Figure 6 The image shows a cutting tape 10 cut along the outer edge of the first ring 14 while the semiconductor wafer 12 and the first ring 14 are attached.

[0028] After that, such as Figure 6In this way, the cutting tape 10, cut off on the outside of the first ring 14, is transported to the extension device (not shown), and the first ring 14 is used to isotropically stretch the cutting tape 10 to separate the semiconductor chips 20 from each other. At this time, as long as the shape of the first ring 14 is the same as that of the conventional cutting ring, the conventional extension device can be used as before. Separating the semiconductor chips 20 from each other is to avoid contact and interference with adjacent chips when picking up the semiconductor chips 20. Subsequently, if the cutting tape 10 is UV-curable, it enters the transfer process, in which the qualified chips that have passed the wafer test, electrical test and appearance inspection are repositioned as products on trays, etc., or assembled into packages, etc., after a UV irradiation process.

[0029] As described above, according to this embodiment, the trimming member 16 is not completely cut off when the blade 28 passes through it, so the trimming member 16 can be reused.

[0030] Furthermore, during the tape cutting process, the inner side of the tape 10, after being cut from the outside of the first ring 14, does not contain the trimming component 16; only the semiconductor wafer 12 and the first ring 14 are attached. Therefore, during the expansion process, the tape 10 can be stretched isotropically.

[0031] Furthermore, since the trimming component 16 is not adhered inside the first ring 14, it is not necessary to remove the trimming component 16 from the cutting tape 10 during expansion for the purpose of isotropically stretching the cutting tape 10. If the trimming component 16 were adhered inside the first ring 14, it would be necessary to remove the trimming component 16 from the cutting tape 10 for isotropic expansion, but this removal could potentially damage the cutting tape 10 or the semiconductor chip 20. In this embodiment, there is no such concern.

[0032] Furthermore, although the above description assumes that trimming is performed each time before the semiconductor wafer 12 is cut, trimming can also be performed after multiple cuts of the semiconductor wafer 12. This reduces the wear on the trimming component 16 and the time spent on the cutting process.

[0033] Implementation Method 2

[0034] The semiconductor wafer dicing method according to Embodiment 2 will be described. Here, the differences from Embodiment 1 will be mainly described.

[0035] In this embodiment, if chipping occurs due to the cutting of the semiconductor wafer 12 by the blade 28, the blade 28 using the trimming member 16 is trimmed before the next cutting of the semiconductor wafer 12. Whether chipping has occurred can be confirmed either visually or by analyzing images captured by a camera.

[0036] As described above, according to this embodiment, trimming is performed each time a chipping occurs, thus suppressing the occurrence of subsequent chipping. Furthermore, compared to the case where trimming is performed each time before the semiconductor wafer is cut, the number of trimming operations is reduced, thus also reducing the wear of the trimming component 16 and the time spent on the cutting process.

[0037] Implementation Method 3

[0038] use Figure 7 The semiconductor wafer dicing method according to Embodiment 3 will be described. Here, the differences from Embodiment 1 will be mainly described.

[0039] In this embodiment, during the cutting process, such as Figure 7 As shown by arrow A, trimming is performed by passing the blade 28 (not shown) along the length of the trimming member 16 through the upper part of the trimming member 16. Figure 7 On the paper, the length direction of trimming component 16 is left and right.

[0040] The semiconductor wafer 12 is cut by cutting the semiconductor wafer 12 along the length direction of the trimming member 16 with the blade 28 as shown by arrow B. Then, the blade 28 is trimmed again as shown by arrow A. Next, the semiconductor wafer 12 is cut as shown by arrow C, which is offset from arrow B. This process of trimming the blade 28 and cutting the semiconductor wafer 12 is repeated to complete the cutting in one direction. When cutting in one direction is completed, the cutting direction is rotated 90 degrees, and the same process is repeated.

[0041] In addition, Figure 7 Only one trimming component 16 is shown, but this is for illustrative purposes; in reality, as shown... Figure 1 That would require at least two. Figure 7 In the middle, the trimming component 16 (not shown) is used in trimming after rotating the cutting direction by 90 degrees.

[0042] As described above, according to this embodiment, since the blade 28 passes through the trimming member 16 along its length, the trimming effect of the blade 28 is improved. When the blade 28 passes along the length of the trimming member 16, the trimming time is longer compared to when it passes along the shorter side. Because the trimming time is longer, the blade 28 can be sufficiently trimmed.

[0043] Furthermore, in the above description, the trimming of the blade 28 is assumed to be performed each time before the semiconductor wafer 12 is cut, but trimming can also be performed after multiple cuts of the semiconductor wafer 12. Alternatively, it can be performed each time a chipping occurs.

[0044] In addition, in the case of Figure 7 In the multiple trimming processes indicated by arrow A, the position of the blade 28 on the upper part of the trimming component 16 in the direction of its short side can be staggered during each trimming or periodically. This results in reduced wear on the trimming component 16.

Claims

1. A method for dicing a semiconductor wafer, wherein, have: The bonding process involves bonding the semiconductor wafer, the first ring, the trimming component, and the second ring onto the cutting tape in such a manner that the first ring is positioned to surround the semiconductor wafer, the trimming component is positioned to the outside of the first ring, and the second ring is positioned to surround the first ring and the trimming component. The cutting process involves multiple cuts of the semiconductor wafer using blades, performed after the bonding process and until the semiconductor wafer is separated into semiconductor chips. The tape cutting process involves, after the cutting process, cutting the tape on the outside of the first ring such that the trimming component and the second ring are not included on the inside. In the cutting process, the blade passes over the upper part of the trimming component without completely cutting it off, thereby trimming the blade.

2. The semiconductor wafer dicing method according to claim 1, wherein, In the cutting process, the trimming is performed before the semiconductor wafer is cut.

3. The semiconductor wafer dicing method according to claim 1, wherein, In the cutting process, if chipping occurs due to the cutting of the semiconductor wafer, the trimming is performed before the next cutting of the semiconductor wafer.

4. The method for dicing a semiconductor wafer according to any one of claims 1 to 3, wherein, The dressing is performed by passing the blade along the length of the dressing component over the upper part of the dressing component. The semiconductor wafer is cut by cutting the semiconductor wafer along the length of the trimming component using the blade.

5. The method for dicing a semiconductor wafer according to any one of claims 1 to 3, wherein, The blade passes over the first ring during the transfer from the trimming to the cutting of the semiconductor wafer. The blade is positioned differently in the height direction when it passes over the trimming member, over the first ring, and when it cuts the semiconductor wafer.

6. The semiconductor wafer dicing method according to claim 4, wherein, The blade passes over the first ring during the transfer from the trimming process to the cutting of the semiconductor wafer. The blade is positioned differently in the height direction when it passes over the trimming member, over the first ring, and when it cuts the semiconductor wafer.

Images