Laser annealing optical system

Abstract

The invention discloses a laser annealing optical system, which belongs to the field of laser annealing. The system includes a machine, a laser system, a motion system and a process chamber. The motion system includes a crossbeam moving in the y-axis direction, a first mounting plate moving in the x-axis direction and a second mounting plate moving in the z-axis direction; a first reflector, a second reflector and a third reflector are respectively arranged on the crossbeam, the first mounting plate and the second mounting plate. The top of the process chamber is sealed by sealing glass. The laser output by the laser system is reflected to the x-axis direction by the first reflector, the second reflector and the third reflector, and then enters the galvanometer and the field mirror in turn after passing through the shaping module, and irradiates the SiC wafer in the process chamber through the sealing glass. In the present invention, the wafer is fixed, the optical path of the laser system moves on the motion system, the process chamber is sealed, the particles in the process are easy to control, and the process effect is good.

Description

Technical Field

[0001] The invention relates to the field of laser annealing, in particular to a laser annealing optical system. Background Art

[0002] Silicon carbide (SiC) is one of the main representatives of the third generation of semiconductors. It has significant performance advantages such as large bandgap, high device limit operating temperature, large critical breakdown electric field strength, and thermal conductivity. It is very popular in electric vehicles, power supplies, military industry, aerospace and other fields, and has opened up new application possibilities for the development of many industries. The industry has high hopes for it. The laser annealing process is a key process step in the manufacturing process of silicon carbide chips.

[0003] At present, the SiC laser annealing machine mainly includes: laser system and motion system for carrying SiC wafer. The laser system is fixed and the motion system moves with SiC wafer, so that the laser system can scan the whole wafer for laser annealing.

[0004] Figure 1 This is a silicon carbide laser annealing machine in the prior art, wherein the numerical labels respectively represent 1: laser system, 2: motion system for carrying wafers, 3: marble platform, and the laser and the motion system are both installed on the marble platform.

[0005] The existing SiC laser annealing machine uses a motion system to move the wafer, which causes the wafer to be exposed to the air. The particles generated by the motion system during the movement will affect the effect of the laser annealing process. At the same time, with the development of SiC technology, some laser annealing processes require the wafer to be processed in an inert gas environment. The current laser annealing equipment is difficult to achieve, especially the lower the oxygen concentration requirement in the inert gas environment, the greater the difficulty of implementation. Adding a process chamber to protect the wafer on the motion system faces the following difficulties: the sealing of the process chamber in the motion system, the scalability and service life of the pipeline that introduces inert gas into the process chamber on the motion system, and the particle control inside the process chamber. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a laser annealing optical system. In the present invention, the wafer is fixed, the optical path of the laser system moves on the motion system, the process chamber is sealed, the particles in the process are easy to control, and the process effect is good.

[0007] The present invention provides the following technical solutions:

[0008] A laser annealing optical system comprises a machine platform, on which a laser system, a motion system and a process chamber are arranged, wherein:

[0009] The motion system comprises a beam capable of moving in the y-axis direction relative to the machine platform, a first mounting plate capable of moving in the x-axis direction relative to the beam is arranged on the beam, and a second mounting plate capable of moving in the z-axis direction relative to the first mounting plate is arranged on the first mounting plate;

[0010] The crossbeam is provided with a first reflector, the first mounting plate is provided with a second reflector, and the second mounting plate is provided with a third reflector, a shaping module, a galvanometer and a field mirror;

[0011] The process chamber is arranged in a depression on the upper surface of the machine platform, and the top of the process chamber is sealed by a sealing glass;

[0012] The laser light in the y-axis direction output by the laser system is reflected by the first reflector to the x-axis direction, then by the second reflector to the z-axis direction, then by the third reflector to the x-axis direction, and then passes through the shaping module and enters the galvanometer and field mirror in sequence, and is irradiated onto the SiC wafer in the process chamber through the sealing glass.

[0013] Furthermore, the laser system includes a laser and a beam expander. The laser is arranged along the y-axis direction. The laser emitted by the laser in the y-axis direction passes through the beam expander and outputs the laser in the y-axis direction.

[0014] Furthermore, the laser system includes a laser, a beam expander and a fourth reflector. The laser is arranged along the x-axis direction. The laser emitted by the laser in the x-axis direction passes through the beam expander and is then reflected to the y-axis direction by the fourth reflector, thereby outputting laser in the y-axis direction.

[0015] Furthermore, a connecting plate is provided on the crossbeam, and the first reflector is connected to the connecting plate via a first bracket; the second reflector is connected to the first mounting plate via a second bracket; and the third reflector is connected to the second mounting plate via a third bracket.

[0016] Furthermore, the laser and the beam expander are fixedly connected to the platform, and the fourth reflector is connected to the platform via a fourth bracket.

[0017] Furthermore, a focal length measuring instrument and a visual positioning system are also provided on the second mounting plate.

[0018] Furthermore, a first slide rail along the y-axis direction is fixedly provided on the machine platform, and the crossbeam cooperates with the first slide rail; a second slide rail along the x-axis direction is fixedly provided on the crossbeam, and the first mounting plate cooperates with the second slide rail; a third slide rail along the z-axis direction is fixedly provided on the first mounting plate, and the second mounting plate cooperates with the third slide rail.

[0019] Furthermore, the focal length measuring instrument is connected to the second mounting plate via a focal length measuring instrument bracket.

[0020] Furthermore, a mounting hole is opened on the machine platform, and the process chamber is installed in the mounting hole and fixed by screws.

[0021] Furthermore, the sealing glass is adsorbed on the process chamber by vacuum.

[0022] The present invention has the following beneficial effects:

[0023] The wafer of the present invention is fixed, the optical path of the laser system moves on the motion system, the process chamber is easy to seal, and the oxygen-free environment control of the process chamber is easy to achieve. The process chamber is small in size, and the time for introducing inert gas to establish an oxygen-free environment is short. During the process, since there is no motion system to move the wafer, particles generated by the motion are avoided, so it is easy to control the particles in the process and the process effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of a silicon carbide laser annealing machine in the prior art;

[0025] Figure 2 It is a schematic diagram of the laser annealing optical system of the present invention;

[0026] Figure 3 is a schematic diagram of the second mounting plate and the structure thereon;

[0027] Figure 4 Schematic diagram of the motion system. DETAILED DESCRIPTION

[0028] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0029] The present invention provides a laser annealing optical system, such as Figure 2-4 As shown, the machine platform 100 is provided with a laser system 200, a motion system 300 and a process chamber 400, wherein:

[0030] The motion system 300 includes a beam 301 capable of moving in the y-axis direction relative to the machine 100, a first mounting plate 302 capable of moving in the x-axis direction relative to the beam 301 is arranged on the beam 301, and a second mounting plate 303 capable of moving in the z-axis direction relative to the first mounting plate 302 is arranged on the first mounting plate 302.

[0031] The x-axis, y-axis, and z-axis directions of the present invention refer to Figure 2If the direction of the view changes, the directions of the x-axis, y-axis, and z-axis will also change accordingly.

[0032] A first reflector 304 is disposed on the crossbeam 301 , a second reflector 305 is disposed on the first mounting plate 302 , and a third reflector 306 , a shaping module 307 , a galvanometer 308 and a field lens 309 are disposed on the second mounting plate 303 .

[0033] The above structure enables the first reflector to move in the y-axis direction, the second reflector to move in the x-axis and y-axis directions, and the third reflector to move in the x-axis, y-axis and z-axis directions.

[0034] The process chamber 400 is disposed in a recess on the upper surface of the platform 100 , and the top of the process chamber 400 is sealed by a sealing glass 410 .

[0035] When the present invention is used, the SiC wafer is first placed on the vacuum chuck of the process chamber by a robot and fixed, and a quartz sealing glass is installed on the upper part of the process chamber. Then, by moving the crossbeam, the first mounting plate and the second mounting plate, the galvanometer and the field mirror on the second mounting plate are moved to the upper part of the process chamber.

[0036] The laser light in the y-axis direction output by the laser system 200 is reflected by the first reflector 304 to be in the x-axis direction, and then by the second reflector 305 to be in the z-axis direction, and then by the third reflector 306 to be in the x-axis direction. Then, the laser light passes through the shaping module 307 along the x-axis direction and enters the galvanometer 308, and finally enters the field lens 309. The laser light emitted from the field lens passes through the sealing glass 410 on the process chamber and irradiates the processed SiC wafer in the process chamber 400, thereby finally realizing the laser annealing process of the wafer.

[0037] The advantages of the present invention are: the wafer is fixed, the laser system optical path moves on the motion system, the process chamber is easy to seal, and the oxygen-free environment control of the process chamber is easy to achieve. The process chamber is small in size, and the time for introducing inert gas to establish an oxygen-free environment is short. During the process, since there is no motion system to move the wafer, particles generated by the motion are avoided, so it is easy to control the particles in the process and the process effect is good.

[0038] In the present invention, the laser system can be placed in a variety of ways, and two examples are given below.

[0039] Example 1:

[0040] like Figure 2-4As shown, the laser system 200 includes a laser 210, a beam expander 220 and a fourth reflector 230. The laser 210 is arranged along the x-axis direction. The laser light in the x-axis direction emitted by the laser 210 passes through the beam expander 220, and then is reflected to the y-axis direction by the fourth reflector 230, and outputs the laser light in the y-axis direction.

[0041] The laser in this example is arranged along the x-axis direction. The laser emits laser light in the x-axis direction and passes through a beam expander to expand the spot size. The laser light is converted into output in the y-axis direction through a single reflection by the fourth reflector. This arrangement makes the system more compact.

[0042] In this example, a connecting plate 310 is provided on the beam 301 , the first reflector 304 is connected to the connecting plate 310 via a first bracket 311 ; the second reflector 305 is connected to the first mounting plate 302 via a second bracket 312 ; and the third reflector 306 is connected to the second mounting plate 303 via a third bracket 313 .

[0043] The laser 210 and the beam expander 220 are fixedly connected to the platform 100 , and the fourth reflector 230 is connected to the platform 100 via a fourth bracket 240 .

[0044] Example 2:

[0045] The laser system 200 includes a laser 210 and a beam expander 220 . The laser 210 is arranged along the y-axis direction. The laser 210 emits laser light in the y-axis direction and outputs laser light in the y-axis direction after passing through the beam expander 220 .

[0046] The laser in this example is arranged along the y-axis direction, so that the laser emitted by the laser is directly output in the y-axis direction, and a reflector can be omitted.

[0047] In the present invention, a focal length measuring instrument 314 and a visual positioning system 315 are also provided on the second mounting plate 303. The focal length measuring instrument and the visual positioning system move together with the second connecting plate, and can realize the movement of the x-axis, y-axis and z-axis. The visual positioning system realizes the positioning of the center of the wafer with the movement of the X, Y and Z axes of the motion system, and the focal length measuring instrument realizes the measurement of the focal length of the laser system with the movement of the X, Y and Z axes of the motion system.

[0048] In the present invention, there can be multiple motion structures in the three directions of X, Y, and Z axes, and a specific example is given here: the first slide rail 110 along the y-axis direction is fixedly provided on the machine 100, and the crossbeam 301 cooperates with the first slide rail 110; the second slide rail 316 along the x-axis direction is fixedly provided on the crossbeam 301, and the first mounting plate 302 cooperates with the second slide rail 316; the third slide rail 317 along the z-axis direction is fixedly provided on the first mounting plate 302, and the second mounting plate 303 cooperates with the third slide rail 317. The motion structure is simple and convenient, with high precision, and the motion of the X, Y, and Z axes of the motion system does not affect the quality of laser transmission in the optical path.

[0049] The focal length measuring instrument 314 may be connected to the second mounting plate 303 via a focal length measuring instrument bracket 318 .

[0050] In order to fix the process chamber, a mounting hole is opened on the machine platform 100, and the process chamber 400 is installed in the mounting hole and fixed by screws. The sealing glass 410 above the process chamber is adsorbed on the process chamber 400 by vacuum.

[0051] The machine platform of the present invention can be a marble machine platform.

[0052] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A laser annealing optical system, characterized in that: The invention comprises a machine platform, on which a laser system, a motion system and a process chamber are arranged, wherein: The motion system comprises a beam capable of moving in the y-axis direction relative to the machine platform, a first mounting plate capable of moving in the x-axis direction relative to the beam is arranged on the beam, and a second mounting plate capable of moving in the z-axis direction relative to the first mounting plate is arranged on the first mounting plate; The crossbeam is provided with a first reflector, the first mounting plate is provided with a second reflector, and the second mounting plate is provided with a third reflector, a shaping module, a galvanometer and a field mirror; The process chamber is arranged in a depression on the upper surface of the machine platform, a vacuum chuck is arranged in the process chamber, a SiC wafer is fixedly placed on the vacuum chuck of the process chamber, and the top of the process chamber is sealed by a sealing glass; The laser system is fixed on the machine platform. The laser light in the y-axis direction output by the laser system is reflected by the first reflector to the x-axis direction, then by the second reflector to the z-axis direction, then by the third reflector to the x-axis direction, and then passes through the shaping module and enters the galvanometer and field mirror in sequence, and is irradiated onto the SiC wafer in the process chamber through the sealing glass.

2. The laser annealing optical system according to claim 1, characterized in that: The laser system comprises a laser and a beam expander. The laser is arranged along the y-axis direction. The laser emitted by the laser in the y-axis direction passes through the beam expander and then outputs the laser in the y-axis direction.

3. The laser annealing optical system according to claim 1, characterized in that: The laser system includes a laser, a beam expander and a fourth reflector. The laser is arranged along the x-axis direction. The laser emitted in the x-axis direction passes through the beam expander and is then reflected in the y-axis direction by the fourth reflector, thereby outputting laser in the y-axis direction.

4. The laser annealing optical system according to claim 3, characterized in that: A connecting plate is provided on the crossbeam, and the first reflector is connected to the connecting plate via a first bracket; the second reflector is connected to the first mounting plate via a second bracket; and the third reflector is connected to the second mounting plate via a third bracket.

5. The laser annealing optical system according to claim 4, characterized in that: The laser and the beam expander are fixedly connected to the platform, and the fourth reflector is connected to the platform via a fourth bracket.

6. The laser annealing optical system according to any one of claims 1 to 5, characterized in that: The second mounting plate is also provided with a focal length measuring instrument and a visual positioning system.

7. The laser annealing optical system according to claim 6, characterized in that: A first slide rail along the y-axis direction is fixedly arranged on the machine platform, and the crossbeam cooperates with the first slide rail; a second slide rail along the x-axis direction is fixedly arranged on the crossbeam, and the first mounting plate cooperates with the second slide rail; a third slide rail along the z-axis direction is fixedly arranged on the first mounting plate, and the second mounting plate cooperates with the third slide rail.

8. The laser annealing optical system according to claim 6, characterized in that: The focal length measuring instrument is connected to the second mounting plate via a focal length measuring instrument bracket.

9. The laser annealing optical system according to claim 6, characterized in that: A mounting hole is provided on the machine platform, and the process chamber is mounted in the mounting hole and fixed by screws.

10. The laser annealing optical system according to claim 9, characterized in that: The sealing glass is adsorbed on the process chamber by vacuum.

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