CN-122003598-A - Thermal imaging method for crack and hole detection in semiconductor device

Abstract

The present disclosure relates to a system including a first laser light source configured to emit laser light, a first focusing lens configured to direct the laser light from the first laser light source onto a first face of a workpiece, a thermal camera configured to capture a thermal image of a second face of the workpiece orthogonal to the first face, and a processor configured to identify a crack in the workpiece based on the thermal image.

Inventors

• PORAT EYAL
• R. Yujif
• N. Turk
• Y. Paskofer
• K. Wan Rosen
• B million Gil Bergen
• F. Buya
• K. Knopus

Assignees

• 奥宝科技有限公司

Dates

Publication Date

20260508

Application Date

20241101

Priority Date

20240327

Claims (20)

1. 1. A system, comprising: a first laser light source configured to emit laser light; a first focusing lens configured to direct the laser light from the first laser light source onto a first face of a workpiece; a thermal camera configured to capture a thermal image of a second face of the workpiece, wherein the second face is orthogonal to the first face, and A processor configured to identify a crack in the workpiece based on the thermal image.
2. 2. The system of claim 1, further comprising: a first scanning mirror configured to direct the laser light from the first laser light source to scan across the first face of the workpiece.
3. 3. The system of claim 1, further comprising: a stage, wherein the workpiece is disposed on the stage, and the stage is movable to scan the laser light from the first laser light source across the first face of the workpiece.
4. 4. The system of claim 1, wherein the first face has a smaller cross-sectional area than the second face.
5. 5. The system of claim 4, wherein the laser has a diameter less than or equal to a thickness of the first face of the workpiece.
6. 6. The system of claim 1, wherein the first face has a larger cross-sectional area than the second face.
7. 7. The system of claim 6, wherein the first focusing lens is configured to direct the laser onto the first face of the workpiece near an edge adjoining the first face and the second face.
8. 8. The system of claim 1, further comprising: a second laser light source configured to emit laser light, and A second focusing lens configured to direct the laser light from the second laser light source onto the first face of the workpiece at a location offset from the laser light from the first laser light source.
9. 9. The system of claim 1, further comprising: a third laser light source configured to emit laser light, and A third focusing lens configured to direct the laser light from the third laser light source onto a third face of the workpiece, wherein the third face is orthogonal to the second face and parallel to the first face.
10. 10. The system of claim 9, further comprising: A fourth laser light source configured to emit laser light; a fourth focusing lens configured to direct the laser light from the fourth laser light source onto a fourth face of the workpiece, wherein the fourth face is orthogonal to the second face and the first face; A fifth laser light source configured to emit laser light, and A fifth focusing lens configured to direct the laser light from the fifth laser light source onto a fifth face of the workpiece, wherein the fifth face is orthogonal to the second face and parallel to the fourth face.
11. 11. The system of claim 1, wherein the thermal camera is a Forward Looking Infrared (FLIR) camera.
12. 12. The system of claim 1, wherein the processor is configured to identify the crack in the workpiece based on the thermal image by: obtaining an intensity of each pixel of the thermal image along an edge of the workpiece adjacent the first face and the second face; Deriving a gradient map using the intensity of each pixel of the thermal image, the gradient map representing a spatial derivative of a temperature distribution along the edge of the workpiece adjacent the first face and the second face, and Determining that the crack in the workpiece is present where a peak is present in the gradient map.
13. 13. A method, comprising: emitting laser light from a first laser light source; Directing the laser light from the first laser light source onto a first face of a workpiece using a first focusing lens; Capturing a thermal image of a second side of the workpiece using a thermal camera, wherein the second side is orthogonal to the first side, and A processor is employed to identify a crack in the workpiece based on the thermal image.
14. 14. The method as recited in claim 13, further comprising: The laser light from the first laser light source is scanned across the first face of the workpiece using a first scanning mirror.
15. 15. The method as recited in claim 13, further comprising: A stage is moved relative to the laser to scan the laser light from the first laser light source across the first face of the workpiece, wherein the workpiece is disposed on the stage.
16. 16. The method as recited in claim 13, further comprising: emitting laser light from a second laser light source, and The laser light from the second laser light source is directed with a second focusing lens onto the first face of the workpiece at a location offset from the laser light from the first laser light source.
17. 17. The method as recited in claim 13, further comprising: emitting laser light from a third laser light source, and Directing the laser light from the third laser light source onto a third face of the workpiece with a third focusing lens, wherein the third face is orthogonal to the second face and parallel to the first face.
18. 18. The method as recited in claim 17, further comprising: emitting laser light from a fourth laser light source; Directing the laser light from the fourth laser light source onto a fourth face of the workpiece with a fourth focusing lens, wherein the fourth face is orthogonal to the second face and the first face; Emitting laser light from a fifth laser light source, and Directing the laser light from the fifth laser light source onto a fifth face of the workpiece with a fifth focusing lens, wherein the fifth face is orthogonal to the second face and parallel to the fourth face.
19. 19. The method of claim 13, wherein the workpiece is disposed on a stage, and the method further comprises: The stage is rotated about an axis perpendicular to the laser light from the first laser light source such that the laser light from the first laser light source is directed with the first focusing lens onto a fourth face of the workpiece, wherein the fourth face is orthogonal to the second face and the first face.
20. 20. The method of claim 13, wherein identifying, with the processor, the crack in the workpiece based on the thermal image comprises: obtaining an intensity of each pixel of the thermal image along an edge of the workpiece adjacent the first face and the second face; Deriving a gradient map using the intensity of each pixel of the thermal image, the gradient map representing a spatial derivative of a temperature distribution along the edge of the workpiece adjacent the first face and the second face, and Determining that the crack in the workpiece is present where a peak is present in the gradient map.

Description

Thermal imaging method for crack and hole detection in semiconductor device Cross reference to related applications The present application claims 2023, 11, 3 and is assigned priority to the provisional patent application of U.S. application No. 63/547,147, the disclosure of which is hereby incorporated by reference. Technical Field The present disclosure relates to semiconductor manufacturing, and more particularly to inspection processes for the detection of defects in semiconductor and solid state battery manufacturing. Background The evolution of the electronics manufacturing industry places increasing demands on yield management, and in particular, on metrology and inspection systems. Critical dimensions continue to shrink and industry needs to reduce the time for achieving high yield, high value production. Minimizing the total time from detection of a yield problem to resolution of the problem maximizes the return on investment for the electronic manufacturer. Manufacturing semiconductor devices such as logic and memory devices typically involves processing semiconductor wafers using a large number of manufacturing processes to form various features and multiple levels of the semiconductor device. For example, photolithography is a semiconductor manufacturing process that involves transferring a pattern from a reticle to a photoresist disposed on a semiconductor wafer. Additional examples of semiconductor fabrication processes include, but are not limited to, chemical Mechanical Polishing (CMP), etching, deposition, and ion implantation. An arrangement of a plurality of semiconductor devices fabricated on a single semiconductor wafer may be divided into individual semiconductor devices. Inspection processes are used at various steps during electronic fabrication to detect defects on wafers, electronic devices, or circuits to facilitate higher yields and thus higher profits in the fabrication process. Inspection has been an important part of manufacturing electronic devices such as Integrated Circuits (ICs) and Printed Circuit Boards (PCBs), including assembled PCBs. However, as emerging markets (e.g., electric vehicles and others) strive for increased reliability requirements, detection of structural defects in reduced-size packaged semiconductor devices has become necessary because even relatively small defects can cause undesirable failure of the device during its complete life cycle. During the dicing process of separating individual semiconductor devices from a single wafer, cracks may form along edges around the perimeter of the semiconductor devices. To identify these cracks, a single sidewall of a Near Infrared (NIR) or Short Wave Infrared (SWIR) illumination device is employed, and a camera captures images on the opposite sidewall. NIR or SWIR light is transmitted through the translucent semiconductor device and the crack casts shadows that can be detected in images captured by the camera on opposite sides. However, this detection method is limited to translucent semiconductor devices and is not applicable to opaque semiconductor devices. Accordingly, a method capable of detecting defects in an opaque semiconductor device is needed. Disclosure of Invention Embodiments of the present disclosure provide a system comprising a first laser light source configured to emit laser light, a first focusing lens configured to direct the laser light from the first laser light source onto a first face of a workpiece, a thermal camera (THERMAL CAMERA) configured to capture a thermal image of a second face of the workpiece, wherein the second face is orthogonal to the first face, and a processor configured to identify a crack in the workpiece based on the thermal image. In some embodiments, the system further comprises a first scanning mirror configured to direct the laser light from the first laser light source to scan across the first face of the workpiece. In some embodiments, the system further comprises a stage. The workpiece may be disposed on the stage, and the stage may be movable to scan the laser light from the first laser light source across the first face of the workpiece. In some embodiments, the first face has a smaller cross-sectional area than the second face. The laser may have a diameter less than or equal to a thickness of the first face of the workpiece. In some embodiments, the first face has a larger cross-sectional area than the second face. The first focusing lens may be configured to direct the laser light onto the first face of the workpiece near an edge adjoining the first face and the second face. In some embodiments, the system further comprises a second laser light source configured to emit laser light, and a second focusing lens configured to direct the laser light from the second laser light source onto the first face of the workpiece at a location offset from the laser light from the first laser light source. In some embodiments, the system further comprises a third laser lig