Design and specific patterns of purge gas laminar flow for laser processing

Abstract

This document provides a system and method for laser annealing. [Solution] The method combines a laminar or nearly laminar flow 117 of purge gas across the wafer / target with greater flow and pressure in the upper portion 111 of the wafer annealing chamber 100 and a specific progression of the laser processing pattern associated with the direction of the laminar flow 117 of the purge gas, thereby minimizing turbulence without interfering with the laser beam path 123 and directing the debris cloud 115 to the outlet 109.

Description

Technical Field

[0001] Cross - reference to related applications

[0001] This application claims the priority and benefit of U.S. Provisional Patent Application No. 63 / 728957, filed on December 6, 2024, with the title "PURGE GAS LAMINAR FLOW DESIGN AND WITH SPECIFIC PATTERN FOR LASER PROCESSING", and incorporates the entire disclosure herein by reference.

Background Art

[0002]

[0002] The limitations and disadvantages of conventional methods and systems for laser annealing will become apparent to those skilled in the art through a comparison of such techniques with the methods and system configurations of the present disclosure described in the remaining part of this disclosure with reference to the drawings.

Summary of the Invention

[0003]

[0003] A method for designing a controlled atmosphere chamber, substantially illustrated and / or described in relation to at least one of the drawings, is more fully defined in the claims.

Brief Description of the Drawings

[0004] [Figure 1] FIG. 1 shows a side view of a wafer annealing chamber, by way of example, in accordance with various illustrative embodiments of this disclosure.

Modes for Carrying Out the Invention

[0005]

[0006] The following considerations provide various examples of annealing chambers. Such examples are not limiting, and the scope of the appended claims should not be limited to the specific examples disclosed. In the following considerations, the terms "example" and "e.g." are not limiting.

[0006]

[0007] The drawings illustrate the configuration in a general style, and to avoid unnecessarily obscuring this disclosure, well-known features and technical descriptions and details may be omitted. Furthermore, the components depicted in the drawings are not necessarily drawn to scale. For example, the dimensions of some components in the drawings are made larger than those of others to facilitate understanding of the examples considered in this disclosure. The same reference numeral in various drawings refers to the same component.

[0007]

[0008] The term "or" means any one or more items in the list connected by "or". For example, "x or y" means any element of the 3-element set {(x), (y), (x,y)}. Another example is "x, y, or z" meaning any element of the 7-element set {(x), (y), (z), (x,y), (x,z), (y,z), (x,y,z)}.

[0008]

[0009] The terms “comprise,” “comprising,” “includes,” and / or “including” are “open-ended” terms that specify the existence of the stated configuration but do not exclude the existence or addition of one or more other configurations.

[0009]

[0010] Here, terms such as "first," "second," etc., may be used to describe various components, and these terms should not limit those components. These terms are simply used to distinguish one component from another. For example, the first component considered in this disclosure may be named the second component without deviating from the teachings of this disclosure.

[0010]

[0011] Unless otherwise specified, the term “combined” can be used to describe two components that are in direct contact with each other, or that two components are indirectly connected by one or more other components. For example, when component A is combined with component B, component A may be in direct contact with component B, or it may be indirectly connected to component B by an intervening component C. Similarly, the terms “over” or “on” can be used to describe two components that are in direct contact with each other, or that two components are indirectly connected by one or more other components.

[0011]

[0012] This disclosure relates to laser annealing for creating improved electrical contacts for semiconductor devices.

[0012]

[0013] Laser processing energy is required to convert the metal thin film and the surface layer of the underlying silicon carbide (SiC) substrate in Azdepo into silide ohmic contacts. However, this laser processing energy causes partial vaporization of the target material and substrate. This vaporization can create a debris cloud that partially absorbs the incoming laser processing energy. Furthermore, the vaporization can contaminate nearby unannealed surfaces. The resulting partial absorption and scattering cause changes in the laser energy delivered to the target area, thereby reducing the effectiveness of the processing.

[0013]

[0014] This disclosure relates to laser annealing for creating improved electrical contacts with respect to semiconductor devices.

[0014]

[0015] Figure 1 shows a side view of an example wafer annealing chamber 100 in accordance with various examples of the implementation of this disclosure.

[0015]

[0016] The laser annealing chamber 100 is designed to optimize debris management and ensure uniform annealing of SiC wafers. At the heart of the design is a wafer support platform 101, positioned within a chamber characterized by a rectangular or cylindrical geometric shape. Purge gas inlets 103, 105 are strategically located along one side of the chamber, while exhaust ports 107, 109 are located on the opposite side. This configuration facilitates a directional gas flow that pushes across the wafer surface. To further enhance debris management, the upper section 111 of the chamber is conical, creating a pressure-increasing zone 119. This pressure gradient ensures that the purge gas flow in the lower section 113 of the chamber is directional and effective, minimizing turbulence without interfering with the laser beam path and directing debris 115 towards the exhaust system.

[0016]

[0017] Chamber 100 includes a gas flow mechanism, which uses a nozzle or array of extended openings to produce a laminar or nearly laminar flow 117 of gas across the wafer. This flow can be adjusted to maintain a velocity range of 0.4 m / s to 1.2 m / s, thereby ensuring efficient removal of debris particles from the wafer surface. The annealing process can be enhanced by selecting a gas composition that includes inert gases such as nitrogen (N2) or argon (Ar), thereby avoiding undesirable chemical reactions during processing.

[0017]

[0018] Debris management is a key feature of this disclosure and addresses the problems posed by vaporized particles during the laser annealing process. The strong laser processing energy interacts with the wafer, creating a debris cloud of carbon nanoparticles and other particles. The system is designed to control and remove this debris before it can interfere with the annealing process or accumulate on critical surfaces.

[0018]

[0019] The purge gas laminar flow 117 plays a central role in debris control. By maintaining a consistent and directional flow across the wafer surface, the system ensures that debris particles 115 remain suspended and are efficiently transported toward the outlet 109. This prevents particles from re-accumulating on the wafer 101 and within the chamber. Furthermore, the conical design of the upper chamber 111 maintains a high-pressure zone 119 that acts as a barrier, preventing debris from contaminating the quartz window 121 for laser beam entry. This feature ensures consistent laser delivery 123, reduces maintenance frequency, and extends the operating life of the chamber components. The chamber may include an internal coating to reduce debris adhesion. The quartz window 121 may include an anti-contamination coating.

[0019]

[0020] This disclosure incorporates a novel approach to the interaction between the laser annealing process and the purge gas flow 117. The laser processing pattern moves in the opposite direction to the laminar gas flow 117. In some embodiments, the galvano scan head can move the beam while the chuck is fixed. In other embodiments, the chuck can move. This ensures that each area of ​​the wafer is annealed on a clean surface because the debris generated by the previous laser processing operation is continuously pushed away before the laser reaches the subsequent area.

[0020]

[0021] This synchronized interaction between the laser processing pattern 123 and the purge gas flow 117 significantly improves the uniformity and efficiency of the annealing process. By preventing the debris cloud 115 from interfering with the laser beam 123, the system ensures consistent energy delivery to the wafer surface 101, thereby improving the annealing results. This method also reduces surface irregularities, improving the overall quality and appearance of the processed wafer. This innovative technique makes the system highly effective in achieving uniform annealing while addressing common problems with debris-related contamination.

[0021]

[0022] While the Method and / or System have been described with reference to specific implementations, it will be understood by those skilled in the art that various modifications and substitutions are possible without exceeding the scope of the Method and / or System. Furthermore, many modifications can be made to the teachings of this disclosure to suit specific circumstances and materials without exceeding their scope. Thus, it is intended that the Method and / or System is not limited to the specific implementation disclosed, but rather includes all implementations within the scope of the appended claims.

Claims

1. A method for laser annealing, A step of determining the direction of the laminar gas flow across the wafer in the lower part of the chamber, A step of creating a pressure boundary in the upper portion of the chamber, The process of performing laser annealing in the opposite direction to the laminar gas flow, A method that includes this.

2. A method according to claim 1, wherein the laminar gas flow uses a purge gas containing one or more of nitrogen, argon, and an inert gas mixture.

3. A method according to claim 1, wherein the chamber includes an array of intake nozzles.

4. A method according to claim 1, wherein the upper portion of the chamber is conical.

5. A method according to claim 1, wherein the gas flow velocity is adjusted according to the wafer size.

6. A method according to claim 1, wherein the laser annealing uses a laser wavelength that is absorbed by the metal layer.

7. A method according to claim 1, wherein the pressure in the chamber is maintained below atmospheric pressure by a vacuum pump.

8. A method according to claim 1, wherein the pressure boundary prevents particles having a size in the range of 0.01 μm to 1.0 μm from entering the upper portion of the chamber.

9. A method according to claim 1, wherein the chamber includes a debris collection system in the discharge path.

10. A method according to claim 1, wherein the laser annealing is configured to minimize the energy scattered by the debris cloud.

11. It is a laser annealing system, A chamber including the lower part of the chamber and the upper part of the chamber, An array of intake nozzles configured to create a laminar gas flow across the wafer, A laser system configured to perform annealing of the wafer using a laser processing pattern that advances in the opposite direction to the laminar gas flow, An exhaust system configured to remove vaporized debris so that it does not accumulate on the wafer again, A system that includes this.

12. The system according to claim 11, wherein the purge gas flow velocity is adjustable between 0.4 and 1.2 m / s.

13. The system according to claim 11, wherein the laser annealing system includes a vacuum pump configured to maintain a chamber pressure lower than atmospheric pressure.

14. The system according to claim 11, wherein the laser system operates at a wavelength optimized for the formation of nickel silicide.

15. A system according to claim 11, wherein the discharge system includes a debris collection unit.

16. The system according to claim 11, wherein the chamber includes an internal coating configured to reduce the adhesion of debris.

17. The system according to claim 11, wherein the direction of the laminar flow is perpendicular to the rotation axis of the wafer.

18. The system according to claim 11, wherein the laser processing pattern can be configured according to the size and material of the wafer.

19. The system according to claim 11, wherein the laser annealing system includes one or more sensors configured to monitor the uniformity of the gas flow.

20. The system according to claim 11, wherein the chamber includes a quartz window with a contamination-resistant coating.

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