JPH0758065A - Chamfering method for semiconductor wafer - Google Patents

Abstract

PURPOSE:To make it possible to chamfer semiconductor wafers and produce a same chamfered shape and protect the shape from being affected by the thickness of the semiconductor wafers. CONSTITUTION:First, the top surface 12A of a wafer attracting rack 12 is positioned on the same surface as on an horizontally extended border (s) line.between an even surface 16 and an upper curved surface 18A formed on a grinding stone 14. Then, the wafer attracting rack 12 is lowered by dimensions to which half (t/2) a preliminarily measured thickness (t) of a semiconductor wafer 10 and half (X3/2) the thickness X3 of the even area formed in the central part around the peripheral edge of the semiconductor wafer 10 are added. Then, the wafer attracting rack 12 is horizontally moved in the direction in which the rack 12 is approaching the grinding stone 14 so that the upper end 10A of the semiconductor wafer 10 is made to abut on an upper slope surface 20A of the grinding stone 14, thereby abrading the upper end area 10A. When the abrasion of the upper end area 10A is finished, the wafer attracting rack 12 is lowered by dimensions in which the thickness (X3) of the even area of the semiconductor wafer 10 is deducted from the width (w) of the even surface 16 of the grinding stone 14 and the lower end area 10B of the semiconductor 10 is abraded with the lower slope surface 20B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for chamfering a semiconductor wafer, and more particularly to a method for chamfering a semiconductor wafer by abutting a peripheral edge of the semiconductor wafer against a rotating grindstone.

[0002]

2. Description of the Related Art A semiconductor wafer cut by a slicing machine has its surface lapped and
The peripheral edge is also chamfered to prevent cracks and prevent dust from adhering. That is, as shown in FIG. 3, the peripheral edge of the semiconductor wafer 2 held by the wafer holder 1 is pressed against the upper inclined surface 3A of the rotating grooved grindstone 3,
After polishing the upper edge of the semiconductor wafer 2, the wafer holder 1 is lowered by a predetermined amount as shown by the chain double-dashed line in the figure to push the lower edge of the semiconductor wafer 2 against the lower inclined surface 3B of the grooved grindstone 3. Apply polishing.

In the conventional method for chamfering a semiconductor wafer, the upper and lower inclined surfaces 3A and 3B of the grindstone 3 with grooves are polished by X.
This is done by setting the 1 and X2 dimensions (see FIG. 4). As a result, at the peripheral edge of the chamfered semiconductor wafer 2, inclined surfaces 2A and 2B are formed by the upper inclined surface 3A and the lower inclined surface 3B, and are formed above and below the flat surface 3C of the grooved grindstone 3. R by curved surface 3D, 3E
The surfaces 2C and 2D are formed, and further, the flat portion 2E is formed between the R surface 3C and the R surface 3D.

[0004]

However, the conventional chamfering method of the semiconductor wafer is the same as that of X1, X2 as described above.
Since the dimensions are set, if the thickness t of the semiconductor wafer 2 is thinner than the basic dimension, or if the curvatures of the curved surfaces 3D and 3E of the grooved grindstone 3 are larger than the basic dimension, the semiconductor wafer 2 The flat portion 2E is lost as shown in FIG. 5, and the portion 2F where the flat portion 2E is originally formed has a drawback that it is sharp.

The present invention has been made in view of the above circumstances, and proposes a method for chamfering a semiconductor wafer that can make the chamfered shape of the semiconductor wafer the same without being affected by the thickness of the semiconductor wafer. The purpose is to do.

[0006]

In order to achieve the above object, the first invention of the present invention is such that a flat surface is formed in the central portion of the peripheral edge, and upper curved surfaces are formed at the upper and lower ends of the flat surface. A surface of a semiconductor wafer to be chamfered by rotating a grooved grindstone having an upper inclined surface and a lower inclined surface formed through a lower curved surface and abutting the peripheral edge of the semiconductor wafer held on a wafer holding table to the grooved grindstone. In the taking method, on the horizontal extension line of the boundary between the flat surface and the upper curved surface formed on the grooved grindstone,
The wafer holder is moved so that the upper surface of the wafer holder is located on the same plane, and is formed in the center of the peripheral edge of the semiconductor wafer by ½ of the thickness of the semiconductor wafer measured in advance and by chamfering. The wafer holding table is lowered by a size obtained by adding 1/2 of the thickness of the flat portion, and the wafer holding table is horizontally moved so that the upper edge of the semiconductor wafer contacts the upper inclined surface of the grooved grindstone. The upper edge of the semiconductor wafer is polished by contacting it, and the lower edge of the semiconductor wafer is lowered by lowering the wafer holder by a dimension obtained by subtracting the thickness of the flat portion of the semiconductor wafer from the width of the flat surface of the grooved grindstone. It is characterized by polishing on the lower inclined surface of a grindstone with a groove.

According to a second aspect of the present invention, in order to achieve the above-mentioned object, a flat surface is formed at the center of the peripheral edge, and an upper curved surface and a lower curved surface are formed on the upper and lower ends of the flat surface. In a chamfering method of a semiconductor wafer, a chamfering process is performed by rotating a grindstone with a groove on which an inclined surface and a lower inclined surface are formed, and abutting the peripheral edge of the semiconductor wafer held on a wafer holding table to the grooved grindstone. Enter the width dimension of the flat part formed in the central part of the peripheral edge of the wafer by chamfering, the radius of curvature of the upper curved surface and the lower curved surface of the grindstone with grooves, and the inclination angle of the upper inclined surface and the lower inclined surface. Then, the wafer is chamfered.

[0008]

According to the first aspect of the present invention, first, the upper surface of the wafer holder is positioned on the same plane on the horizontal extension line of the boundary between the flat surface and the upper curved surface formed on the grooved grindstone. .
Next, ½ of the thickness of the semiconductor wafer measured in advance,
The wafer holder is lowered by a dimension obtained by adding 1/2 of the thickness of the flat portion formed in the central portion of the peripheral edge of the semiconductor wafer by the chamfering process. Then, the wafer holder is horizontally moved to bring the upper edge of the semiconductor wafer into contact with the upper inclined surface of the grooved grindstone to polish the upper edge.

When the polishing of the upper edge portion of the semiconductor wafer is completed, the wafer holding table is lowered by the dimension of the width of the flat surface of the grooved grindstone minus the thickness of the flat portion of the semiconductor wafer, and the lower edge of the semiconductor wafer is lowered. The part is ground on the lower inclined surface of the whetstone with a groove. According to the second aspect of the present invention, the width dimension of the flat portion formed in the central portion of the peripheral edge of the wafer by the chamfering process, the radius of curvature of the upper curved surface and the lower curved surface of the grooved grindstone, and the upper inclined surface and the lower inclined surface. The chamfering of the wafer is performed by inputting the inclination angle of the surface.
As a result, the chamfered shape of the semiconductor wafer can be made the same without being affected by the thickness of the semiconductor wafer.

Further, the value of the width of the flat portion may be zeroed to form the peripheral surface of the wafer into a curved surface.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a chamfering method for a semiconductor wafer according to the present invention will be described in detail below with reference to the accompanying drawings. The semiconductor wafer 10 shown in FIG. 1 is suction-held on an upper surface 12A of a wafer suction table 12 which is a holding mechanism of the semiconductor wafer 10.

On the other hand, the grindstone 14 has a flat surface 16 formed at the center of the peripheral edge thereof, and the upper and lower ends of the flat portion 16 are provided with an upper curved surface 18A and a lower curved surface 18B through an upper inclined surface 20A and a lower surface. It is formed as a grindstone with a groove in which the inclined surface 20B is formed, and the inclined surfaces 20A and 20B are configured as polishing surfaces. Further, the grindstone 14 is rotated at a predetermined rotation speed by the rotation axis PP. As shown in FIG. 2, the rotation axis P-P is the central axis Q- for holding the semiconductor wafer 10.
It is arranged parallel to Q in the vertical direction.

Next, the semiconductor wafer 1 using the grindstone 14
The chamfering method of 0 will be described. First, as shown in FIG. 1, the upper surface 12A of the wafer suction table 12 is located on the same plane on the horizontal extension line of the boundary portion s between the flat surface 16 formed on the grindstone 14 and the upper curved surface 18A. Next, half (t / 2) of the thickness t of the semiconductor wafer 10 measured in advance and the thickness X3 (see FIG. 2) of the flat portion 10C formed in the central portion of the peripheral edge of the semiconductor wafer 10 by chamfering. Half (X3
/ 2) and the wafer suction table 12
Is lowered as indicated by the chain double-dashed line in FIG.

Next, the wafer suction table 12 is horizontally moved in a direction approaching the grindstone 14 to move the upper edge portion 1 of the semiconductor wafer 10.
0A is brought into contact with the upper inclined surface 20A of the grindstone 14, and the upper edge 10
Polish A. When the polishing of the upper edge portion 10A is completed, the wafer suction table 12 is lowered by the size obtained by subtracting the thickness X3 of the flat portion 10C of the semiconductor wafer 10 from the width w of the flat surface 16 of the grindstone 14 and the semiconductor wafer 10 The lower edge 10B is shown in FIG.
Polishing is performed on the lower inclined surface 20B as indicated by the middle two-dot chain line.

As a result, in the present embodiment, the processing method is simpler than the conventional chamfering processing method, and the semiconductor wafer 1 is
The chamfered shape of the semiconductor wafer can be surely made the same without being influenced by the thickness t of 0. That is, the thickness X3 of the flat portion 10C of the semiconductor wafer 10 can be obtained with a constant dimension. In this embodiment, after polishing the upper edge 10A of the semiconductor wafer 10 and then polishing the lower edge 10B, another chamfering method is to polish the lower edge 10B and then the upper edge. 10A may be polished. In this case, first, the flat surface 16 formed on the grindstone 14 and the lower curved surface 1
The wafer suction table 1 is placed on the horizontal extension line of the boundary with 8B.
The upper surface 12A of the second wafer 2 is located on the same plane, and then half the thickness t of the semiconductor wafer 10 measured in advance (t / 2),
Half the thickness X3 of the flat portion 10C of the semiconductor wafer 10 (X
3/2) is added, and the wafer suction table 12 is moved down by the size. Next, the wafer suction table 12 is horizontally moved to bring the lower edge portion 10B of the semiconductor wafer 10 into contact with the lower inclined surface 20B of the grindstone 14 to polish the lower edge portion 10B. Lower edge 1
When the polishing of 0B is completed, the width w of the flat surface 16 of the grindstone 12
Then, the wafer suction table 12 is raised by a size obtained by adding the above (t / 2) and (X3 / 2) to the size obtained by subtracting the thickness X3 of the flat portion 10C of the semiconductor wafer from the semiconductor wafer 10
The upper edge portion 10A may be polished with the upper inclined surface 20A.

In the present embodiment, the chamfering is performed while the semiconductor wafer 10 is stopped, but the chamfering may be performed by rotating the semiconductor wafer 10. Furthermore, in this embodiment, the semiconductor wafer 10 is pressed against the grindstone 14, but the grindstone 14 may be pressed against the semiconductor wafer 10. On the other hand, as another embodiment of the present invention, the width dimension w of the flat portion 16 formed in the central portion of the peripheral edge of the semiconductor wafer 10 by the chamfering process, the upper curved surface 18A and the lower curved surface 18 of the grooved grindstone 14.
B curvature radius value, and upper inclined surface 20A and lower inclined surface 20B
Since the chamfering of the wafer is performed by inputting the inclination angle of, the chamfered shape of the semiconductor wafer 10 can be made the same without being affected by the thickness of the semiconductor wafer 10.

Further, by inputting the value of the width dimension w of the flat portion 16 as zero, the peripheral surface 1 of the wafer where the flat portion is originally formed is
0C may be formed in a curved shape as shown in FIG.

[0018]

As described above, according to the chamfering method for a semiconductor wafer according to the first aspect of the present invention, the chamfered shape of the semiconductor wafer can be made the same without being influenced by the thickness of the semiconductor wafer. it can. According to the chamfering method for a semiconductor wafer according to the second aspect of the present invention, the width dimension of the flat portion formed in the central portion of the peripheral edge of the wafer by the chamfering process, the radius of curvature values of the upper and lower curved surfaces of the whetstone with a groove. Since the chamfering of the wafer is performed by inputting the inclination angles of the upper inclined surface and the lower inclined surface, the chamfered shape of the semiconductor wafer can be made the same without being affected by the thickness of the semiconductor wafer. .

Further, the value of the width of the flat portion may be zeroed to form the peripheral edge of the wafer into a curved surface.

[Brief description of drawings]

FIG. 1 is a side view showing an initial setting position of a wafer holding table in a chamfering method according to the present invention.

FIG. 2 is an enlarged view of an essential part showing a chamfering condition of a chamfering method according to the present invention.

FIG. 3 is an enlarged view of an essential part of a chamfered wafer chamfered by another embodiment of the chamfering method according to the present invention.

FIG. 4 is a side view showing a chamfering condition of a conventional chamfering method.

FIG. 5 is a side view of an essential part showing a basic chamfered shape of a semiconductor wafer.

FIG. 6 is a side view of a main portion of a semiconductor wafer in which a sharp portion is formed in the center of a chamfered portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Semiconductor wafer 12 ... Wafer adsorption | suction table 14 ... Whetstone 16 ... Flat surface 20A, 20B ... Inclined surface

Claims (3)

[Claims] 1. A grooved grindstone in which a flat surface is formed at the center of the peripheral edge, and an upper sloped surface and a lower sloped surface are formed on the upper and lower ends of the flat surface through upper and lower curved surfaces, respectively. In a chamfering method of a semiconductor wafer, which is rotated, and a peripheral edge of a semiconductor wafer held on a wafer holding table is brought into contact with the grooved grindstone, the flat surface and the upper curved surface formed on the grooved grindstone. The wafer holder is moved so that the upper surface of the wafer holder is located on the same plane on the horizontal extension line of the boundary with the chamfering process. By lowering the wafer holder by a dimension obtained by adding 1/2 of the thickness of the flat portion formed in the central portion of the peripheral edge of the semiconductor wafer, and horizontally moving the wafer holder to move the upper edge of the semiconductor wafer. Abutting the upper part of the grindstone with grooves The upper edge portion is polished, and the wafer holding table is lowered by the dimension of the flat surface of the grooved grindstone minus the thickness of the flat portion of the semiconductor wafer to lower the lower edge of the semiconductor wafer to the grooved grindstone. A method for chamfering a semiconductor wafer, which comprises polishing the lower inclined surface. 2. A grooved grindstone in which a flat surface is formed at the center of the peripheral edge, and an upper sloped surface and a lower sloped surface are formed on the upper and lower ends of the flat surface through an upper curved surface and a lower curved surface, respectively. In a chamfering method of a semiconductor wafer, which is rotated, and a peripheral edge of a semiconductor wafer held on a wafer holding table is brought into contact with the grooved grindstone to form a chamfer, which is formed in a central portion of the peripheral edge of the wafer by chamfering. A semiconductor wafer characterized by performing chamfering of a wafer by inputting a width dimension of a flat portion, radius-of-curvature values of the upper curved surface and the lower curved surface of a whetstone with grooves, and an inclination angle of the upper inclined surface and the lower inclined surface. Chamfering method. 3. The semiconductor device according to claim 2, wherein the value of the width dimension of the flat portion formed in the central portion of the peripheral edge of the wafer is zero-input to form the peripheral surface of the wafer into a curved surface. Wafer chamfering method.