JP2004111799A - Manufacture of semiconductor chip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of cracking or chipping in the periphery of a semiconductor wafer, which is a problem in reducing the thickness of the wafer in the manufacture of a semiconductor chip. <P>SOLUTION: The manufacture of a semiconductor chip comprises; a step (A) for sticking a protective tape to the surface of a chamfered wafer, on which a number of semiconductor chips are formed; a step (B) for thinning the rear of the wafer; a step (C) for sticking a dicing tape to the rear of the wafer, and for mounting the wafer on a dicing frame; and a step (D) for separating the protective film from the surface of the wafer. Prior to the step (A), the edge surfaces of the wafer are rechamfered, the protective tape is stuck to the surface of the rechamfered wafer, and the thickness of the wafer is reduced by grinding/polishing/etching the rear surface. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of manufacturing a semiconductor chip by thinning a semiconductor wafer, and more particularly to a method of manufacturing a semiconductor chip by preventing cracks and chipping in a peripheral portion of a wafer which is a problem in thinning a wafer.
[0002]
[Prior art]
JP-A-5-29455 describes a method for manufacturing a semiconductor chip by thinning a semiconductor wafer. Specifically, the method of manufacturing a semiconductor chip described in this publication has the contents shown in FIG. 4, and a surface protection sheet 2 is attached to the surface of a semiconductor wafer 1 as shown in FIG. Thereafter, as shown in FIG. 4 (b), a step of grinding the back surface of the semiconductor wafer, and as shown in FIG. 4 (c), attaching a back sheet 3 to the back surface of the semiconductor wafer, and simultaneously forming a frame on the outer periphery of the back sheet. 4 and a dicing step of peeling off the surface protection sheet 2 as shown in FIG. 4 (d) and dividing the semiconductor wafer into individual chips as shown in FIG. 4 (e). is there.
[0003]
[Problems to be solved by the invention]
If an attempt is made to form a semiconductor chip having a thickness of 25 to 50 μm (specifically, for example, about 50 μm) by the method described in the above-mentioned publication, chipping or cracking may occur in the step of thinning the semiconductor wafer. And cause damage to the internal elements, or damage during the subsequent process of attaching the dicing tape, the mounting process, the dicing process, and the transfer of the wafer after thinning, resulting in a lower non-defective product rate. It has been found that there is a possibility that such a problem may occur. The occurrence of such a problem arises from the fact that the peripheral end face of the semiconductor wafer is usually formed into a rounded shape called a round chamfer so that no damage or chipping occurs at the time of contact with the jig in the previous process. FIGS. 1A and 1B are diagrams for explaining a problem that occurs when a round-chamfered semiconductor wafer is thinned. In the test by the present inventor, especially when the desired thickness becomes 50 μm or less, the edge face of the thinned wafer becomes physically acute, and the frequency of chipping and cracking from the wafer edge face decreases. It has been found that the above-mentioned problem tends to occur more frequently.
[0004]
[Means for Solving the Problems]
The present invention provides a method for manufacturing a semiconductor chip that solves the above-mentioned problems. In the method for manufacturing a semiconductor chip according to the present invention, a step (A) of attaching a protective tape to a chamfered wafer surface on which a large number of semiconductor chips are formed, a step (B) of thinning the back surface of the wafer, In the method for manufacturing a semiconductor chip, the method further comprises a step (C) of attaching a dicing tape to the back surface and mounting the wafer on a dicing frame, and a step (D) of peeling off the protective tape on the surface of the wafer. Before, the end surface of the wafer is re-chamfered, the protective tape is attached to the surface of the re-chamfered wafer, and the back surface of the wafer is thinned by grinding and / or polishing and / or etching. .
In the method of manufacturing a semiconductor chip according to the present invention, the re-chamfering of the wafer end face is performed at a substantially vertical chamfering angle, and the re-chamfering is performed between a starting point of the first chamfering and a point reaching a desired thickness in the first chamfering. It is preferable to chamfer. Further, it is preferable that the re-chamfering comprises a vertical portion and an R-chamfered portion.
[0005]
[Example of embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.
[0006]
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a semiconductor wafer (control IC wafer) [FIG. 1 (a) and FIG. 1 (b)] which has been chamfered, and a wafer form obtained by re-chamfering the wafer according to the present invention [FIG. c) and FIG. 1 (d)]. FIG. 3 shows a semiconductor chip of the present invention in which a semiconductor chip (a control IC wafer) that has already been chamfered is re-chamfered, and then the thinning of the wafer, cutting of the wafer, and chip separation are sequentially performed to manufacture a semiconductor chip. It is a flowchart which shows a manufacturing process.
[0007]
FIG. 1A is an external view of a semiconductor wafer (control IC wafer) which has already been chamfered, and FIG. 1B is an enlarged view of an end face of the wafer shown in FIG. FIG. 1C is an enlarged view of the end face of the wafer shown in FIG. 1A, which is substantially vertically re-chamfered, and FIG. 1D is a view of the wafer after the thinned re-chamfered wafer shown in FIG. It is an enlarged view of a wafer end surface. As is apparent from FIGS. 1 (a) to 1 (d), the re-chamfering of the wafer is performed at the starting point of the existing chamfer (the first chamfering) and the point at which the desired thickness of the existing chamfer is reached. By re-chamfering, the edge of the wafer is not physically sharpened in the thinning process during the re-chamfering, so that the wafer surface is not damaged, and chipping from the wafer edge is performed. The frequency of occurrence of cracks and cracks can be prevented from increasing. As shown in FIG. 1 (c), a protective tape is attached to the surface of the re-chamfered semiconductor wafer (see [Control IC Wafer]-[Regrinding of the end face] in FIG. 3). ], And grinding and / or polishing and / or etching the back surface of the wafer to stably produce a thinned wafer as shown in FIG. 1D (see [grinding and polishing] in FIG. 3). can do.
[0008]
Thereafter, a dicing tape is attached to the back surface of the wafer according to the processing procedure after [grinding and polishing] in the flowchart of FIG. 3, and the step of mounting the wafer on a dicing frame; and the step of peeling off the protective tape on the surface of the wafer. Through the dicing step of dividing the semiconductor wafer into individual chips, the wafer is diced into semiconductor chips.
[0009]
FIG. 2 shows a second embodiment of the present invention. FIGS. 2C and 2D correspond to FIGS. 1C and 1D, respectively. FIG. 2 (c) is an enlarged view of an end face of a semiconductor wafer (control IC wafer) which has already been chamfered, which is substantially perpendicularly re-chamfered, and wherein the re-chamfering comprises a vertical portion and an R chamfered portion. FIG. 2D is an enlarged view of the end face after the wafer shown in FIG. 2C is thinned.
In this embodiment, as shown in the first embodiment above, the vertical portion of the re-chamfering of the wafer is re-chamfered between the starting point of the existing chamfer and the point where the existing chamfer reaches the desired thickness. Further, by making the front side of the re-chamfered wafer a R-chamfered portion for re-chamfering, damage to the wafer front side during the re-chamfering can be further prevented. The effect in the thinning step is the same as that of the first embodiment described above, and the end face of the wafer does not become a physical acute angle, and the frequency of chipping and cracking from the wafer end face increases. Can be prevented.
[0010]
As shown in the first embodiment, a protective tape is applied to the front surface of the wafer which has been re-chamfered as shown in FIG. 2 (c), and then the back surface of the wafer is ground and / or polished and / or ground. Alternatively, a thinned wafer as shown in FIG. 2D can be manufactured stably by etching. Then, as in the first embodiment described above, a dicing tape is attached to the back surface of the wafer and the wafer is mounted on a dicing frame according to the processing procedure after [grinding and polishing] in the flowchart of FIG. And a step of peeling off the protective tape on the wafer surface and a dicing step of dividing the semiconductor wafer into individual chips to singulate the wafer into semiconductor chips.
[0011]
【The invention's effect】
As described in detail above, according to the present invention, the end face of the semiconductor wafer that has already been chamfered is re-chamfered, and the distance between the starting point of the existing chamfer and the point reaching the desired thickness of the existing chamfer is obtained. Then, a protective tape is attached to the surface of the wafer, and the back surface of the wafer is ground and / or polished and / or etched to prevent cracks from the wafer end surface and to reduce the thickness of the wafer. Thus, an improvement in the non-defective rate in the subsequent individualization step is achieved. In particular, it is extremely effective in enabling ultra-thin wafers with a thickness of 50 μm or less and singulation. Further, by configuring the re-chamfering to include a vertical portion and an R-chamfered portion, damage to the wafer surface side can be further reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first embodiment example of the present invention.
FIG. 2 is a diagram showing a second embodiment of the present invention.
FIG. 3 is a flowchart showing steps of a method for manufacturing a semiconductor chip of the present invention.
FIG. 4 is a flowchart showing steps of a conventional method for manufacturing a semiconductor chip by thinning a semiconductor wafer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Semiconductor wafer 2 Surface protection sheet 3 Back sheet 4 Frame 11 Semiconductor chip (control IC)

Claims (3)

Attaching a protective tape to the surface of the chamfered wafer on which a large number of semiconductor chips are formed (A), thinning the back surface of the wafer (B), attaching a dicing tape to the back surface of the wafer, and attaching the wafer In a method for manufacturing a semiconductor chip having a step (C) of mounting on a dicing frame and a step (D) of peeling off a protective tape on the surface of the wafer, the end face of the wafer is chamfered before the step (A). A method of manufacturing a semiconductor chip, comprising: attaching the protective tape to the front surface of the re-chamfered wafer; and grinding and / or polishing and / or etching the back surface of the wafer to reduce the thickness. The method of claim 1, wherein the re-chamfering of the wafer end surface is performed at a substantially vertical chamfering angle, and re-chamfering is performed between a starting point of the first chamfering and a point reaching a desired thickness of the first chamfering. A manufacturing method of the semiconductor chip described in the above. 3. The method according to claim 2, wherein the re-chamfering includes a vertical portion and an R-chamfered portion.

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