US-20260126400-A1 - OPTICAL INSPECTION OF WAFER BEVELS USING MULTIPLE LIGHT SOURCES

Abstract

Optical inspection of the surface of a substrate may take place in a factory interface where an aligner rotates the substrate to identify an alignment mark. While rotating, light may also be reflected off the surface of the substrate and captured by to identify defects or other variations on the substrate surface. However, the edge of the substrate often includes a bevel, and light directed at the edge of the substrate does not reflect off the bevel into the camera uniformly. Therefore, multiple light sources may be used simultaneously. For example, one light source may be directed perpendicularly at the edge of the bevel while another light source is directed at the bevel edge and configured such that light reflects off of the bevel into the camera. This provides an image with uniform lighting that can be more effectively used to identify defects on the edge of the substrate.

Inventors

• Zhi Wang
• Sidharth Bhatia
• Martin Seamons
• Ganesh Balasubramanian
• Ka Shun Wong

Assignees

• APPLIED MATERIALS, INC.

Dates

Publication Date

20260507

Application Date

20241104

Claims (20)

1. 1 . A semiconductor manufacturing system comprising: an aligner configured to: impart a rotational motion to a wafer; and identify, using the rotational motion of the wafer, a position of a reference feature of the wafer; and an optical inspection system configured to collect, during the rotational motion imparted by the aligner to the wafer, imaging data for a portion of the wafer, wherein the optical inspection system comprises: a camera; a first light source positioned to direct light at a bevel of the wafer; and a second light source positioned to direct light perpendicularly at an edge of the wafer.
2. 2 . The semiconductor manufacturing system of claim 1 , wherein the first light source is closer to the portion of the wafer than the second light source.
3. 3 . The semiconductor manufacturing system of claim 1 , wherein the first light source is at least 10% brighter than the second light source.
4. 4 . The semiconductor manufacturing system of claim 1 , further comprising: a processing device programmed to identify, using the imaging data, a defect in the wafer.
5. 5 . The semiconductor manufacturing system of claim 1 , wherein the aligner and the optical inspection system are located in a factory interface coupled to at least one of a load lock chamber, a transfer chamber, or a processing chamber.
6. 6 . The semiconductor manufacturing system of claim 1 , wherein the rotational motion of the wafer occurs with frequency between 30 rpm and 250 rpm.
7. 7 . The semiconductor manufacturing system of claim 1 , wherein the imaging data is collected for the portion of the wafer located within a distance d/10 from an edge of the wafer, wherein d is a diameter of the wafer.
8. 8 . The semiconductor manufacturing system of claim 1 , further comprising a deposition chamber and a transfer robot, wherein the transfer robot is configured to move the wafer from the aligner to the deposition chamber after capturing the imaging data.
9. 9 . The semiconductor manufacturing system of claim 1 , wherein the camera, the first light source, and the second light source are positioned between about 5 mm and about mm from the wafer.
10. 10 . An optical inspection system comprising: a pedestal configured to impart a rotational motion to a wafer; a camera configured to collect, during the rotational motion of the wafer, imaging data for at least a portion of the wafer; and a first light source positioned to direct light at a bevel of the wafer such that the light reflects off the bevel of the wafer into the camera.
11. 11 . The optical inspection system of claim 10 , further comprising: a processing device programmed to identify, using the imaging data, one or more defects in the bevel of the wafer.
12. 12 . The optical inspection system of claim 10 , further comprising: a second light source positioned to direct light perpendicularly at an edge of the wafer, wherein the second light source is separate and distinct from the first light source.
13. 13 . The optical inspection system of claim 10 , further comprising: a second light source, wherein: the first light source is positioned to direct light at a first portion of the bevel of the wafer; and the second light source is positioned to direct light at a second portion of the bevel of the wafer.
14. 14 . The optical inspection system of claim 10 , wherein the first light source is configured to emit light having a wavelength characterized by a blue color.
15. 15 . The optical inspection system of claim 10 , wherein the first light source comprises a ring light around the camera.
16. 16 . The optical inspection system of claim 10 , wherein the first light source comprises a dome light.
17. 17 . The optical inspection system of claim 10 , wherein the first light source is positioned above a camera to capture the imaging data depicting a top portion of the bevel of the wafer.
18. 18 . A method comprising: imparting a rotational motion to a wafer; directing light at a bevel of the wafer such that the light is reflected off of the bevel of the wafer into a camera; collecting, using the camera, imaging data for the bevel of the wafer, wherein the imaging data is collected during the rotational motion imparted to the wafer; and identifying, using the imaging data, a presence of a defect on the bevel of the wafer.
19. 19 . The method of claim 18 , wherein the defect comprises a chipping defect, a pitting defect, a film delamination defect, a bevel-edge defect, or a staining defect.
20. 20 . The method of claim 18 , further comprising adjusting a brightness of the light to adjust a quality of the imaging data.

Description

TECHNICAL FIELD This disclosure generally describes methods and systems for inspecting wafers manufactured in substrate processing systems. More specifically, this disclosure describes optical inspection techniques for use in identifying defects in substrates with bevel edges. BACKGROUND Manufacturing of modern materials often involves various deposition techniques, such as chemical vapor deposition (CVD) or physical vapor deposition (PVD), in which atoms of one or more selected types are deposited on a substrate (wafer) held in low or high vacuum environments that are provided by vacuum deposition chambers. Manufacturing further includes various other techniques, such as etching, patterning, polishing, cleaning, stress mitigation, and/or the like. Materials manufactured in this manner include monocrystals, semiconductor films, fine coatings, and numerous other substances used in practical applications, e.g., electronic device manufacturing. Many of these applications rely on the quality of the materials grown in substrate processing systems, which in turn depends on the quality of wafers (e.g., bare wafers or wafers that underwent various preprocessing operations) used as substrates for device manufacturing. A wafer/substrate carrier may be docked to a load port of an equipment front end module (factory interface), where one or more substrates may be transferred to a load lock chamber or a process chamber (e.g., by a transfer robot). An environmentally-controlled atmosphere may be provided within and between the substrate carrier and the process chambers. To maintain isolation of inter-chamber environments and to increase product throughput, various robotic techniques of wafer manipulation and wafer inspection techniques may be used. SUMMARY In some embodiments, a semiconductor manufacturing system may include an aligner configured to impart a rotational motion to a wafer and to identify, using the rotational motion of the wafer, a position of a reference feature of the wafer. The semiconductor manufacturing system may also include an optical inspection system configured to collect, during the rotational motion imparted by the aligner to the wafer, imaging data for a portion of the wafer. The optical inspection system may include a camera, a first light source positioned to direct light at a bevel of the wafer, and a second light source positioned to direct light perpendicularly at an edge of the wafer. In some embodiments, an optical inspection system may include a pedestal configured to impart a rotational motion to a wafer; a camera configured to collect, during the rotational motion of the wafer, imaging data for at least a portion of the wafer; and a first light source positioned to direct light at a bevel of the wafer such that the light reflects off the bevel of the wafer into the camera. In some embodiments, a method for inspecting a substrate. The method may include imparting a rotational motion to a wafer; directing light at a bevel of the wafer such that the light is reflected off of the bevel of the wafer into a camera; and collecting, using the camera, imaging data for the bevel of the wafer. The imaging data may be collected during the rotational motion imparted to the wafer. The method may also include identifying, using the imaging data, a presence of a defect on the bevel of the wafer. In any embodiments, any and all of the following features may be implemented in any combination and without limitation. The first light source may be closer to the portion of the wafer than the second light source. The first light source may be at least 10% brighter than the second light source. A processing device may be programmed to identify, using the imaging data, a defect in the wafer. The aligner and the optical inspection system may be located in a factory interface coupled to at least one of a load lock chamber, a transfer chamber, or a processing chamber. The rotational motion of the wafer may occur with frequency between 30 rpm and 250 rpm. The imaging data may be collected for the portion of the wafer located within a distance d/10 from an edge of the wafer, where d is a diameter of the wafer. The system may include a deposition chamber and a transfer robot, where the transfer robot may be configured to move the wafer from the aligner to the deposition chamber after capturing the imaging data. The camera, the first light source, and the second light source may be positioned between about 5 mm and about 100 mm from the wafer. A second light source may be positioned to direct light perpendicularly at an edge of the wafer, where the second light source is separate and distinct from the first light source. The first light source may be positioned to direct light at a first portion of the bevel of the wafer; and the second light source may be positioned to direct light at a second portion of the bevel of the wafer. The first light source may be configured to emit light having a wavelength characterize