CN210722984U

CN210722984U - Laser annealing system

Info

Publication number: CN210722984U
Application number: CN201921880295.0U
Authority: CN
Inventors: 刘效岩; 张程鹏; 王建; 程闻兴
Original assignee: Beijing U Precision Tech Co Ltd
Current assignee: Beijing U Precision Tech Co Ltd
Priority date: 2019-11-04
Filing date: 2019-11-04
Publication date: 2020-06-09
Anticipated expiration: 2029-11-04

Abstract

The utility model discloses a laser annealing system. The laser annealing system includes: a fixed stage (1), a sealable process chamber (2) embedded within the stage (1), and an optical system movable relative to the stage (1); only an adsorption chuck assembly is arranged in the cavity space of the process cavity. According to the utility model discloses a laser annealing system has reduced the volume of process cavity by a wide margin, easily realizes the anaerobic environment control of process cavity to avoided producing the granule because of the system motion in the course of the technology.

Description

Laser annealing system

Technical Field

The utility model relates to a laser annealing system.

Background

The silicon carbide semiconductor has wide potential application fields, and has potential application prospects in the fields of new energy automobiles, rail transit, smart power grids, voltage conversion and the like. With the continuous increase of requirements of light weight, high conversion efficiency and low heat generation characteristics of semiconductor power devices in downstream industries, silicon carbide replacing silicon in the power devices becomes a necessary trend for industry development. The silicon carbide semiconductor is used for completely replacing silicon in the power device manufacturing process at low cost, and several difficulties need to be overcome, wherein the metal ohmic contact process of laser annealing is one of the processes, particularly with the development of the metal ohmic contact process, the process environment is mainly required to be inert gas, the oxygen content in the process environment must reach the index of the process requirement, and thus the requirement on a laser annealing machine is correspondingly improved.

Referring to fig. 1, the current laser annealing machine mainly has an optical system I (e.g., laser) and a stage III fixed, a motion system II carries a sample wafer (e.g., wafer) to be processed to move on X, Y and Z axes, and such laser annealing machine has no process chamber, and the sample wafer to be processed is exposed to the atmosphere. In the laser annealing process, laser irradiation generates high temperature on the surface of the wafer, and oxygen in the air generates oxidation reaction on the surface of the wafer, so that the final laser annealing process is influenced, and particularly the influence on the ohmic contact process of metal is the most serious. With the development of power device manufacturing process, there is also a technology to make the wafer and the motion system into an integral process chamber, and the volume of the process chamber is very large because the motion system is required to be accommodated, so that the amount of inert gas required for establishing an oxygen-free environment meeting the process requirements is large, and the consumption cost of the inert gas is increased; meanwhile, the anaerobic environment needs long time for establishing, and the productivity of the machine is influenced. Meanwhile, the movement system moves in the process chamber to generate particles easily, and the friction generates pollutants such as metal easily, and the generated particles and metal pollutants can directly contact the surface of the wafer, so that the yield of the wafer is influenced finally.

SUMMERY OF THE UTILITY MODEL

In view of this, the main objective of the present invention is to provide a laser annealing system, which includes a fixed platform, a process chamber and a movable optical system, so as to reduce the volume of the process chamber, reduce the influence of particles generated by the movement of the optical system during the process, and protect the robot.

According to an aspect of the present invention, there is provided a laser annealing system, including: a fixed stage, a sealable process chamber embedded within the stage, and an optical system movable relative to the stage; only an adsorption chuck assembly is arranged in the cavity space of the process cavity.

Preferably, the process chamber comprises, from top to bottom: the laser-transparent sealing sheet is positioned at the top of the process chamber, the top mounting component is positioned below the sealing sheet, the bottom mounting component is matched with the top mounting component, and the suction chuck component is fixed on the bottom mounting component.

Preferably, the suction chuck assembly includes a suction chuck adjacent the bottom mounting member, a suction chuck protective ring disposed on an upper surface of the suction chuck, and a wafer protective ring disposed above the suction chuck protective ring at a height.

According to a specific embodiment, the upper surface of the top mounting part is provided with air outlet holes around the circumference of the sealing sheet.

According to another embodiment, the bottom mounting member is provided with a gas inlet, a transition region communicating the gas inlet with the process chamber interior, and a gas outlet for maintaining an oxygen-free environment within the process chamber.

Further, the process chamber is provided with a gate valve outside with respect to the stage.

The gate valve is provided with an opening for conveying a sample wafer to be processed, and a gas opening is arranged at the opening. And an intake pipe is provided inside the door valve.

According to another embodiment, the sealing sheet is vacuum-sucked on top of the process chamber.

Therefore, according to the utility model discloses a laser annealing system is because the sample wafer of pending is fixed, and the process chamber is easily sealed to easily realize process chamber's anaerobic environment control, and the process chamber volume reduces, and the time required for establishing anaerobic environment shortens, has improved production efficiency.

Drawings

Further objects, functions and advantages of the present invention will become apparent from the following description of embodiments of the present invention, with reference to the accompanying drawings, in which:

FIG. 1 shows a schematic diagram of a prior art laser annealing system;

fig. 2 illustrates a platform with a process chamber embedded therein in a laser annealing system according to the present invention;

fig. 3 shows a schematic structural view of a process chamber in a laser annealing system according to the present invention;

fig. 4 is a schematic structural diagram of a fixed platform in the laser annealing system according to the present invention;

figure 5 shows a top view of a top mount of a process chamber in a laser annealing system according to the present invention;

figure 6 illustrates a bottom view of a top mount of a process chamber in a laser annealing system according to the present invention;

figure 7 shows a top view of a bottom mounting component of a process chamber in a laser annealing system according to the present invention;

fig. 8 illustrates a bottom view of a bottom mounting component of a process chamber in a laser annealing system according to the present invention;

fig. 9 shows a schematic structural view of an adsorption chuck of a process chamber in a laser annealing system according to the present invention;

fig. 10 illustrates a schematic structural view of a suction chuck guard ring of a process chamber in a laser annealing system according to the present invention;

figure 11 schematically illustrates a back view of a gate valve of a process chamber in a laser annealing system according to the present invention; and is

Figure 12 schematically illustrates a front view of a gate valve of a process chamber in a laser annealing system according to the present invention.

Detailed Description

According to the utility model provides a laser annealing system, include: a fixed stage, a sealable process chamber embedded within the stage, and an optical system movable relative to the stage; only an adsorption chuck assembly is arranged in the cavity space of the process cavity.

According to one embodiment, referring to fig. 2-4, the laser annealing system of the present invention includes a fixed platform 1 and a process chamber 2 embedded within the platform 1.

Wherein the platform 1 may be, for example, a marble platform and has a trapezoidal structure of holes into which the process chambers 2 are inserted. The process chamber 2 may be preferably inserted by being fixed by screws through first screw holes 9 formed in the lower surface of the top mounting part 3 of the process chamber 2 and second screw holes 8 formed in corresponding positions on the trapezoidal plane of the groove of the stage 1, respectively. The top mounting part 3 and the platform 1 are sealed by a sealing ring.

The process chamber 2 comprises from top to bottom: a laser-transparent sealing sheet 7 at the top of the process chamber, a top mounting member 3 below the sealing sheet 7, a bottom mounting member 4 cooperating with the top mounting member 3, a suction chuck assembly fixed to the bottom mounting member 4.

The sealing sheet 7 may be quartz glass and is typically vacuum-sucked at the top of the process chamber to seal the process chamber. The quartz glass is preferably plated with a double-sided antireflection film, so that the energy loss of laser light is minimum when the laser light penetrates through the quartz glass.

As shown in fig. 2 to 6, an air outlet hole 10 is provided in the upper surface of the top mount member 3 around the seal sheet 7 for blowing particles on the upper surface of the seal sheet 7 to keep the seal sheet 7 clean. The inert gas or clean dry gas (CDA) blown out from the gas outlet 10 reaches the gas outlet 11 after passing through the upper surface of the quartz glass.

A plurality of (e.g., four) third screw holes 15 may be provided in the chamber top mounting member 3 in order to replace quartz glass with a metal plate at the time of leak detection if the sealing sheet 7 is quartz glass, which is not suitable for high vacuum, and fix it to the top mounting member 3 through the third screw holes 15, at the time of vacuum leak detection of the process chamber 2.

The process chamber 2 is also provided with a power meter mounting location 12 and a topographer mounting location 13. The power meter and the topograph are mounted on the top mounting part 3 by screws. The power meter mounting position 12 and the topographer mounting position 13 have intersecting cross hairs that define the center position of the laser.

The top mounting member 3 is provided with a fourth screw hole 16 on the lower surface thereof, and correspondingly, the bottom mounting member 4 is provided with a fifth screw hole 14 on the upper surface thereof at a position corresponding to the fourth screw hole 16. The bottom mounting member 4 and the top mounting member 3 are assembled and fixed by screws through the fourth screw hole 16 and the fifth screw hole 14.

As shown in fig. 7 and 8, the bottom mounting member 4 is provided with a gas inlet 18, a transition zone 19 communicating the gas inlet 18 with the interior of the process chamber 2, and a gas outlet 20 for maintaining an oxygen-free environment within said process chamber 2. The transition area 19 may be, for example, an elongated area. The gas, preferably an inert gas, passes through the transition zone 19 before entering the process chamber 2 through the gas inlet 18, so that the inert gas can enter the process chamber 2 uniformly. The inert gas inlet and outlet are balanced by the gas inlet 18 and exhaust 20 to achieve an oxygen free environment in the process chamber 2 while maintaining a constant pressure within the process chamber 2.

The bottom mounting part 4 also has an opening 17 for robot access to the process chamber 2.

In the above laser annealing system, the suction chuck assembly is fixed to the bottom mounting member 4 in the inner cavity of the process chamber 2. As shown in fig. 9 and 10, the suction chuck assembly includes a suction chuck 5 adjacent to the bottom mounting member 4, a suction chuck guard ring 6 disposed on an upper surface of the suction chuck 5, and a wafer guard ring (not shown) disposed above the suction chuck guard ring 6 at a certain height. Here, the suction chuck protection ring 6 may have the same shape as the suction chuck 5, or may cover only a part of the suction chuck 5.

The suction chuck protection ring 6, the suction chuck (for example, a vacuum suction chuck) 5, and the bottom attachment member 4 are integrally assembled by screws through the sixth screw hole 25 of the suction chuck protection ring 6, the seventh screw hole 21 of the suction chuck 5, and the eighth screw hole 26 of the lower surface of the bottom attachment member 4, which are positioned correspondingly. The first through hole 24 of the suction chuck protection ring 6 and the second through hole 22 of the suction chuck 5 are reserved for inserting holes of support pillars of a wafer protection ring, and the wafer protection ring is supported by the support pillars at a distance higher than the height of the robot entering the process chamber, so as to protect the wafer and prevent the wafer from being broken due to the fact that the laser hits the edge of a sample wafer (such as a wafer) to be processed.

Referring to fig. 11 and 12, the process chamber 2 is provided with a gate valve 31 on the outside relative to the platform 1.

The gate valve 31 is provided with an opening for transporting a sample wafer to be processed (e.g., a wafer), and gas openings (29,30) are provided at the opening. The opening in the gate valve 31 has a corresponding position to the opening 17 in the bottom mounting part 4.

Intake pipes (27,28) are also provided inside the door valve 31.

Specifically, the gate valve is opened during the laser annealing process by using the laser annealing device, the inert gas outlet is arranged on the inner side of the cavity of the gate valve, and after the gate valve of the process cavity is opened, the inert gas outlet on the inner side of the gate valve sprays inert gas to form a gas curtain to prevent atmosphere from entering the process cavity. If the process temperature is high, the temperature of the manipulator can be reduced, and the manipulator is protected. The robot arm places a sample wafer (e.g., a wafer) to be processed on a vacuum chuck in the process chamber, then exits the chamber, the chamber gate valve is closed, and the inert gas inside the gate valve stops injecting. The edge of the vacuum chuck is provided with a protection device for protecting the chuck compatible with wafers with different sizes from being swept by laser to cause loss.

According to another embodiment, the present invention provides a laser annealing method, which is performed using the above laser annealing system. Specifically, a sample wafer to be processed (e.g., a wafer) is placed on a chuck in a process chamber, the process chamber is mounted on a platform (e.g., a marble platform), the platform is stationary with the process chamber, i.e., the wafer is stationary, and an optical system (e.g., a laser system) moves on the platform to perform laser annealing scanning on the wafer.

The laser annealing system and the laser annealing method have the advantages that:

1. the sample wafer (such as a wafer) to be processed is fixed, the process chamber is easy to seal, and the oxygen-free environment control of the process chamber is easy to realize; the process chamber has small volume, small dosage of the introduced inert gas and short time for establishing the anaerobic environment.

2. In the process, the wafer does not move along with the movement system, and the movement easily generates particles, so the particles in the process are easy to control, and the process result is good.

3. An inert gas outlet is arranged on the inner side of the gate valve to spray inert gas to form a gas curtain to prevent atmosphere from entering the cavity, so that the cleanliness of the process cavity is kept, and meanwhile, if the process temperature is high, the temperature of the mechanical arm can be reduced, and the mechanical arm is protected.

Claims

1. A laser annealing system, comprising: a fixed stage (1), a sealable process chamber (2) embedded within the stage (1), and an optical system movable relative to the stage (1); only an adsorption chuck assembly is arranged in the cavity space of the process cavity.

2. The laser annealing system according to claim 1, wherein the process chamber (2) comprises, in sequence from top to bottom: a laser-transparent sealing sheet (7) at the top of the process chamber, a top mounting part (3) below the sealing sheet (7), a bottom mounting part (4) cooperating with the top mounting part (3), a suction chuck assembly fixed to the bottom mounting part (4).

3. The laser annealing system of claim 1 or 2, wherein the suction chuck assembly comprises a suction chuck (5) contiguous with the bottom mounting part (4), a suction chuck guard ring (6) disposed on an upper surface of the suction chuck (5), and a wafer guard ring disposed at a height above the suction chuck guard ring (6).

4. Laser annealing system according to claim 2, characterized in that the upper surface of the top mounting part (3) is provided with gas outlet holes (10) around the circumference of the sealing sheet (7).

5. The laser annealing system according to claim 2, wherein the bottom mounting part (4) is provided with a gas inlet (18), a transition region (19) communicating the gas inlet (18) with the inner cavity of the process chamber (2), and a gas exhaust (20) for maintaining an oxygen-free environment inside the process chamber (2).

6. Laser annealing system according to claim 1, characterized in that the process chamber (2) is provided with a gate valve (31) on the outside with respect to the platform (1).

7. Laser annealing system according to claim 6, characterized in that the gate valve (31) is provided with an opening for transporting a sample wafer to be processed and that a gas opening (29,30) is provided at the opening.

8. Laser annealing system according to claim 6, characterized in that inside the gate valve (31) there are provided gas inlet pipes (27, 28).

9. Laser annealing system according to claim 2, characterized in that the sealing sheet (7) is vacuum-sucked on top of the process chamber (2).