JP-7855356-B2 - processing equipment

Inventors

• 飯塚 健太呂

Assignees

• 株式会社ディスコ

Dates

Publication Date

20260508

Application Date

20220202

Claims (5)

1. A processing apparatus used to calculate the center position of one side of a disc-shaped wafer, and which performs a predetermined processing on the outer periphery of the wafer, A holding unit for holding the wafer, A processing unit for processing the wafer, An imaging unit for imaging the outer periphery of the wafer held by the holding unit, Equipped with, The holding unit is, A disc-shaped holding table for suction holding the wafer, A rotating shaft connected to the holding table for rotating the holding table, A drive unit that rotates the rotating shaft, It has, The imaging unit is, Camera section, A light-emitting unit including a light source is provided below the camera unit, Each of the following is fixed to the axis of rotation and arranged on the outer circumference of the holding table so as to be separated from each other along the circumferential direction of the holding table, and each has a pair of opposing inclined surfaces, and is capable of irradiating light from the light source upward through the pair of inclined surfaces, It has, A processing apparatus characterized by adjusting the position of each reflection unit in the imaging unit so that light from the light source is sequentially irradiated from each reflection unit onto the outer periphery of the wafer, which has a larger diameter than the holding table and extends radially outward from the holding table when held by the holding table, and imaging at least three locations on the outer periphery of the wafer with the imaging unit.
2. The at least three reflective units are, When a first holding table having a first diameter is used as the holding table in the holding unit, at least three first reflective units are provided, each capable of irradiating light from the light source onto the outer periphery of a first wafer that protrudes radially outward from the first holding table when held by the first holding table and has a diameter larger than the first diameter, When a second holding table having a second diameter larger than the first diameter is used in the holding unit instead of the first holding table, at least three second reflective units are provided, each capable of irradiating light from the light source onto the outer periphery of the second wafer, which protrudes radially outward from the second holding table when held by the second holding table and has a diameter larger than the second diameter. The processing apparatus according to claim 1, characterized by including the following:
3. The holding unit further includes an annular auxiliary table provided on the outer periphery of the holding table, The processing apparatus according to claim 1 or 2, characterized in that the auxiliary table includes through holes for irradiating the outer periphery of the wafer with light reflected by each reflection unit.
4. The processing apparatus according to any one of claims 1 to 3, characterized in that the pair of inclined surfaces of each reflective unit include a first mirror surface and a second mirror surface inclined at 45 degrees with respect to a plane perpendicular to the longitudinal direction of the reflective unit on which the pair of inclined surfaces are provided, so as to irradiate light from the light source upward.
5. The processing apparatus according to any one of claims 1 to 4, characterized in that the light-emitting unit is provided directly below the annular trajectory traced by the outer of the pair of inclined surfaces by rotating the rotation axis.

Description

This invention relates to a processing apparatus used to calculate the center position of one surface of a disc-shaped wafer, and to perform a predetermined processing on the outer periphery of the wafer. A disc-shaped wafer having a device region on its surface and an outer peripheral excess region surrounding the device region is known to be processed in which the back region corresponding to the device region is ground to form a circular recess, and a ring-shaped reinforcing portion is left in the region corresponding to the outer peripheral excess region, after which the wafer is divided into device units (see, for example, Patent Document 1). When dividing a wafer into device units according to the processing method described, it is usually necessary to first remove the ring-shaped reinforcing portion. Therefore, a processing apparatus has been proposed that identifies the center position of the wafer surface and then precisely cuts and removes the ring-shaped reinforcing portion based on this center position (see, for example, Patent Documents 2 and 3). In the processing apparatus described in Patent Document 3, a frustocone is provided on the bottom side of the holding surface, and a holding table with a smaller diameter than the wafer is used to determine the center position of the wafer surface. The frustocone is inclined at 45 degrees with respect to the horizontal plane and has an annular inclined surface on its side that functions as a mirror. A light source, such as an LED (Light Emitting Diode), is installed on the side of the frustum of the cone. A camera capable of capturing reflected light is installed above the inclined surface. Light emitted from the light source is reflected upward by the inclined surface and captured by the camera. To calculate the center position of the wafer surface using this frustocone, first, the recess corresponding to the device area formed by grinding is fitted into the holding table, and the wafer is held in place by suction on the holding table. At this time, the outer edge of the wafer extends beyond the outside of the holding table. Next, light is shone from the side onto the side of the frustum, and reflected light from the inclined surface is shone onto the outer edge of the wafer. The outer edge is then imaged using a camera. In particular, by rotating the chuck table, three different locations on the outer edge of the wafer are imaged with the camera. Since the center position (coordinates) on the holding surface of the holding table is known, the center position (center coordinates) of the wafer surface can be calculated based on the positions (coordinates) of three points on the edge obtained by imaging three locations on the outer periphery. However, wafers come in various outer diameters, such as 6 inches (approximately 150 mm), 8 inches (approximately 200 mm), and 12 inches (approximately 300 mm), and the diameter of the circular recess formed on the back side of the wafer varies depending on the wafer diameter. Japanese Patent Publication No. 2007-19461Japanese Patent Publication No. 2014-60224Japanese Patent Publication No. 2020-43186 This is a perspective view of a laser processing machine.Figure 2(A) is a perspective view of the front side of the wafer unit, and Figure 2(B) is a perspective view of the back side of the wafer.This is an enlarged perspective view of the holding unit.This is a partial cross-sectional side view of the holding unit.This is a partial cross-sectional side view showing the imaging process of the outer edge of a wafer.This is a partial cross-sectional side view showing the imaging of the outer edge of a large-diameter wafer.Figure 7(A) is a top view of a holding unit, etc., equipped with a chuck table having a first diameter, and Figure 7(B) is a top view of a holding unit, etc., equipped with a chuck table having a second diameter.This is a partial cross-sectional side view showing a reflective unit according to the third embodiment.This is an enlarged view of the retaining unit in a modified example.This is a partial cross-sectional side view showing the imaging process of the outer edge of a wafer.This is a partial cross-sectional side view showing the imaging of the outer edge of a large-diameter wafer. An embodiment of one aspect of the present invention will be described with reference to the attached drawings. Figure 1 is a perspective view showing an example of the configuration of a laser processing apparatus (processing apparatus) 2. The laser processing apparatus 2 includes a base 4 that supports each structure. The base 4 includes a rectangular parallelepiped base 6 and a wall portion 8 extending upward from the rear end of the base 6. A disc-shaped chuck table (first holding table) 10 is positioned above the base 6. The chuck table 10 holds the disc-shaped wafer (first wafer) 11 to be processed by suction. Here, the wafer 11 will be described with reference to Figures 2(A) and 2(B). The wafer 11 has a single