JP-7855335-B2 - Wafer processing method

Inventors

• 岡村 卓
• 原田 成規

Assignees

• 株式会社ディスコ

Dates

Publication Date

20260508

Application Date

20211110

Claims (3)

1. A method for processing a wafer in which multiple devices are formed on the surface and the outer edge is chamfered, A holding step in which the wafer is rotatable along the circumferential direction of the wafer and is held by suction on the upper surface of a porous plate with its surface facing upward, After the holding step, a processing step is performed in which, with the lower end of the first cutting blade rotating while supplying cutting fluid from a first liquid supply unit provided around the annular first cutting blade and cutting into the outer edge of the wafer, a cleaning fluid is supplied to the center of the surface of the wafer from a second liquid supply unit provided around an annular second cutting blade, which is provided separately from the first cutting blade, and the wafer is rotated to form a film of the cleaning fluid that covers the surface of the wafer, thereby processing the outer edge of the wafer. A wafer processing method comprising [a specific feature].
2. The wafer processing method according to claim 1, further comprising an ultraviolet irradiation step of irradiating the surface of the wafer with ultraviolet light to impart hydrophilicity before the processing step.
3. In the processing step, A cutting step that increases the depth from the surface of the lower end of the rotating cutting blade at the outer edge of the wafer, A rotation step of rotating the wafer at least once, A wafer processing method according to claim 1 or 2, wherein the process is performed alternately and repeatedly.

Description

This invention relates to a method for processing wafers with chamfered outer edges. Chips in devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) are essential components in various electronic devices such as mobile phones and personal computers. Such chips are manufactured, for example, by forming numerous devices on the surface of a wafer made of semiconductor material, and then dividing the wafer into regions containing individual devices. In wafers used for chip manufacturing, cracks are prone to forming at the outer edges where stress concentrates. Therefore, in the chip manufacturing process, the outer edges are generally chamfered prior to various other processes. Furthermore, in the chip manufacturing process, to achieve miniaturization of the manufactured chips, the back surface of the wafer is often ground to thin it before splitting. However, when the back side of a wafer with a chamfered outer edge is ground to thin it, the back side of the outer edge takes on a knife-edge shape. This area is prone to stress concentration and cracking. Therefore, in the chip manufacturing process, wafer edge trimming is often performed after the device is formed on the front side of the wafer and before the back side is ground. Wafer edge trimming is performed, for example, by cutting and removing a portion of the surface at the outer edge of the wafer. This process generates wafer debris (cutting shavings). If these cutting shavings become contaminated with devices formed on the wafer surface, the quality of the chips obtained by splitting the wafer may deteriorate. In view of this, it has been proposed to perform wafer edge trimming while supplying a liquid (cleaning solution) in a curtain-like manner over the entire surface of the wafer (see, for example, Patent Document 1). This prevents the wafer surface from drying out, reducing the likelihood of cutting debris contaminating the device. Japanese Patent Publication No. 2013-225612 Figure 1 is a schematic perspective view showing an example of a cutting apparatus.Figure 2(A) is a schematic top view showing an example of a wafer, and Figure 2(B) is a schematic cross-sectional view showing an example of a wafer.Figure 3 is an exploded perspective view schematically showing the components of the cutting unit.Figure 4 is a schematic side view showing the components of the liquid supply unit.Figure 5 is a flowchart schematically showing an example of a wafer processing method.Figures 6(A), 6(B), and 6(C) are schematic cross-sectional front views illustrating the processing steps.Figure 7 is a schematic front view showing the ultraviolet irradiation step. The embodiments of the present invention will be described with reference to the attached drawings. Figure 1 is a schematic perspective view showing an example of a cutting apparatus used for wafer edge trimming. Note that the X-axis direction (front-to-back direction) and Y-axis direction (left-to-right direction) shown in Figure 1 are mutually orthogonal directions on the horizontal plane, and the Z-axis direction (up-down direction) is orthogonal to the X-axis and Y-axis directions (vertical direction). The cutting apparatus 2 shown in Figure 1 has a base 4 that supports each component. A ball screw type X-axis movement mechanism 6 is provided on the base 4. Specifically, the X-axis movement mechanism 6 has a pair of guide rails 8 that extend along the X-axis direction. A sliding X-axis moving plate 10 is connected to the upper surface of this pair of guide rails 8. A screw shaft 12 extending along the X-axis direction is positioned between the pair of guide rails 8. A motor 14 for rotating the screw shaft 12 is connected to one end of the screw shaft 12. Furthermore, a nut portion (not shown) for housing balls that circulate in accordance with the rotation of the screw shaft 12 is provided on the outer surface of the screw shaft 12 where the screw threads are formed, thus forming a ball screw. Furthermore, this nut is fixed to the underside of the X-axis moving plate 10. Therefore, when the screw shaft 12 is rotated by the motor 14, the X-axis moving plate 10 moves along the X-axis direction together with the nut. A water case 16 is provided around the X-axis movement mechanism 6 to temporarily store the liquid supplied during wafer cutting. The liquid stored in the water case 16 is discharged to the outside of the cutting device 2 via a drain (not shown) or the like. Furthermore, a table base 18 is fixed to the upper surface (front side) of the X-axis movement plate 10. A cylindrical θ-table 20 is provided on the upper surface of this table base 18. Furthermore, a cover 22 with a rectangular top surface is provided around the θ-table 20. A disc-shaped chuck table 24, having a wafer-holding surface at its upper end, is fixed to the top surface of the θ-table 20. Furthermore, the θ-table 20 is connected to a rotational drive source (not shown), such as a motor, for rotating the θ-tabl