Laser cleaning method for semiconductor surface oxide

Abstract

The laser cleaning method for the oxide on the surface of the semiconductor comprises the steps that the semiconductor is placed in a negative-pressure vacuum chamber, and the surface of the semiconductor is located at the focal plane position of a laser pulser; the laser pulse frequency of the laser pulser is controlled to be 1 Hz to 200 Hz, and the laser pulse width of the laser pulser is controlled to be 0.1 ns to 100 ns; the average laser power of the laser pulser is controlled to be 100-1000W, and the laser energy density is controlled to be 0.1 J / cm < 2 >-2J / cm < 2 >. Compared with a traditional cleaning method, the method has the advantages that the treatment process is faster, higher surface cleaning quality is obtained, surface oxides of semiconductors are effectively removed, and secondary pollution to the environment is reduced.

Description

Technical Field

[0001] The present invention relates to the field of laser processing, and particularly to a laser cleaning method for semiconductor surface oxides. Background Art

[0002] During the processing of semiconductors, there are usually many impurities and contaminants on their surfaces. Such substances are usually mainly composed of oxides, and it is difficult to remove them from the semiconductor surface. In the past, cleaning methods were mostly used, such as using a liquid mixture of acids, alkalis or strong oxidants. However, these methods cannot effectively and completely remove the surface oxides of semiconductors, and are also prone to causing secondary pollution to the environment.

[0003] Therefore, there is an urgent need for an improved laser cleaning method for semiconductor surface oxides to overcome the above defects. Summary of the Invention

[0004] The object of the present invention is to provide an improved laser cleaning method for semiconductor surface oxides. This method has a faster processing flow compared to traditional cleaning methods, obtains higher surface cleaning quality, thus effectively removing the surface oxides of semiconductors, and reducing secondary pollution to the environment.

[0005] To achieve the above object, the laser cleaning method for semiconductor surface oxides of the present invention uses a pulsed laser to clean the semiconductor, and includes the following steps:

[0006] Place the semiconductor in a vacuum chamber under negative pressure, and the surface of the semiconductor is located at the focal plane position of the laser pulser;

[0007] Control the laser pulse frequency of the laser pulser to be 1 Hz - 200 Hz, and the laser pulse width to be 0.1 ns - 100 ns;

[0008] Control the average laser power of the laser pulser to be 100 - 1000 W, and the laser energy density to be 0.1 J / cm 2 -2 J / cm 2 .

[0009] Compared with the prior art, the present invention uses a pulsed laser to clean the semiconductor. The semiconductor is placed in a vacuum chamber under negative pressure, and the surface of the semiconductor is located at the focal plane position of the laser pulser. For oxide particles of different nanoscale levels, by optimizing the control of the laser pulse frequency, laser pulse width, average laser power and laser energy density, the oxide particles on the semiconductor surface can be effectively removed. It has a faster processing flow compared to traditional cleaning methods, and reduces secondary pollution to the environment, and is suitable for industrial promotion and use.

[0010] As a preferred embodiment, when the surface oxide of the semiconductor has a first size, control the laser pulse frequency to be 120 Hz - 200 Hz, the laser pulse width to be 80 ns - 100 ns, the laser average power to be 750 - 1000 W, and the laser energy density to be 1.8 J / cm 2 -2.0 J / cm 2 .

[0011] As a preferred embodiment, when the surface oxide of the semiconductor has a second size, control the laser pulse frequency to be 70 Hz - 120 Hz, the laser pulse width to be 45 ns - 80 ns, the laser average power to be 250 - 750 W, and the laser energy density to be 0.6 J / cm 2 -1.8 J / cm 2 .

[0012] As a preferred embodiment, when the surface oxide of the semiconductor has a third size, control the laser pulse frequency to be 30 Hz - 70 Hz, the laser pulse width to be 15 ns - 45 ns, the laser average power to be 150 - 250 W, and the laser energy density to be 0.3 J / cm 2 -0.6 J / cm 2 .

[0013] As a preferred embodiment, when the surface oxide of the semiconductor has a fourth size, control the laser pulse frequency to be 1 Hz - 30 Hz, the laser pulse width to be 0.1 ns - 15 ns, the laser average power to be 100 - 150 W, and the laser energy density to be 0.1 J / cm 2 -0.3 J / cm 2 .

[0014] As a preferred embodiment, control the laser scanning speed of the laser pulse generator on the surface of the semiconductor to be 5 mm / s - 50 mm / s.

[0015] As a preferred embodiment, control the laser cleaning time of the laser pulse generator on the surface of the semiconductor to be 1 - 5 minutes.

[0016] Preferably, after the cleaning is completed, increase the negative pressure in the vacuum chamber to evacuate the suspended oxide particles in the vacuum chamber. Detailed implementation mode

[0017] To make the above objects, features, and advantages of the present application more apparent and understandable, the following describes the specific implementation manners of the present application in detail with reference to some embodiments. Many specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0018] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0019] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0020] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation manner.

[0021] The following further describes the laser cleaning method of the semiconductor surface oxide of the present invention with reference to embodiments, but does not limit the present invention thereby. The method of the present invention aims to provide a laser cleaning method for semiconductor surface oxides, which has a faster processing flow and higher surface cleaning quality compared with traditional cleaning methods, thereby effectively removing the surface oxides of semiconductors and reducing secondary pollution to the environment.

[0022] In an embodiment of the laser cleaning method of the semiconductor surface oxide of the present invention, a pulsed laser is used to clean the semiconductor, including the following steps:

[0023] Place the semiconductor in a vacuum chamber under negative pressure, with the surface of the semiconductor located at the focal plane position of the laser pulser.

[0024] Control the laser pulse frequency of the laser pulser to be 1 Hz - 200 Hz, and the laser pulse width to be 0.1 ns - 100 ns.

[0025] Control the average laser power of the laser pulser to be 100 - 1000 W, and the laser energy density to be 0.1 J / cm 2 - 2 J / cm 2 .

[0026] The present invention uses a pulsed laser to clean the semiconductor. The semiconductor is placed in a vacuum chamber under negative pressure, and the surface of the semiconductor is located at the focal plane position of the laser pulser. For oxide particles of different nanoscale sizes, by optimizing the control of the laser pulse frequency, laser pulse width, average laser power, and laser energy density, the oxide particles on the semiconductor surface can be effectively removed. Compared with traditional cleaning methods, it has a faster processing flow and reduces secondary pollution to the environment, and is suitable for industrial promotion and use.

[0027] Specifically, in the present invention, first place the semiconductor to be cleaned in a vacuum chamber, with its surface located at the laser focal plane position of the pulsed laser. The vacuum chamber is controlled in a near-vacuum environment under negative pressure, or in a protective atmosphere such as argon, to prevent further oxidation of the semiconductor surface. Preferably, a pulsed laser is used to perform laser scanning on the semiconductor surface to remove residual oxides and other debris. For oxide particles of different sizes, the cleaning can be completed by controlling different parameters of the laser pulser. Specifically, the laser pulse frequency is 1 Hz - 200 Hz, the laser pulse width is 0.1 ns - 100 ns, the average laser power is 100 - 1000 W, and the laser energy density is 0.1 J / cm 2 - 2 J / cm 2 .

[0028] In one embodiment, when the surface oxide of the semiconductor has a first size, such as 8 - 10 nanometers, control the laser pulse frequency to be 120 Hz - 200 Hz, the laser pulse width to be 80 ns - 100 ns, the average laser power to be 750 - 1000 W, and the laser energy density to be 1.8 J / cm 2 - 2.0 J / cm 2 .

[0029] In another embodiment, when the surface oxide of the conductor has a second size, such as 5 - 8 nanometers, control the laser pulse frequency to be 70 Hz - 120 Hz, the laser pulse width to be 45 ns - 80 ns, the average laser power to be 250 - 750 W, and the laser energy density to be 0.6 J / cm 2-1.8 J / cm 2 。

[0030] In yet another embodiment, when the surface oxide of the semiconductor has a third dimension, such as 1 - 5 nanometers, the laser pulse frequency is controlled to be 30 Hz - 70 Hz, the laser pulse width is 15 ns - 45 ns, the laser average power is 150 - 250 W, and the laser energy density is 0.3 J / cm 2 -0.6 J / cm 2 。

[0031] In still another embodiment, when the surface oxide of the semiconductor has a fourth dimension, such as less than 1 nanometer, the laser pulse frequency is controlled to be 1 Hz - 30 Hz, the laser pulse width is 0.1 ns - 15 ns, the laser average power is 100 - 150 W, and the laser energy density is 0.1 J / cm 2 -0.3 J / cm 2 。

[0032] The oxide particles after laser cleaning become tiny dust suspended in the vacuum chamber, increasing the negative pressure in the vacuum chamber, thereby sucking away the suspended oxide particles in the vacuum chamber.

[0033] In summary, the present invention uses a pulsed laser to clean the semiconductor, places the semiconductor in a vacuum chamber with negative pressure, and the surface of the semiconductor is located at the focal plane position of the laser pulser. For oxide particles of different nanoscale levels, by optimizing the control of the laser pulse frequency, laser pulse width, laser average power, and laser energy density, the oxide particles on the semiconductor surface can be effectively removed. Compared with traditional cleaning methods, it has a faster processing flow and reduces secondary pollution to the environment, and is suitable for industrial promotion and use.

[0034] The above-disclosed are only the preferred embodiments of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Therefore, equivalent changes made according to the scope of the patent application of the present invention still fall within the scope covered by the present invention.

Claims

1. A laser cleaning method for semiconductor surface oxides, which uses a pulsed laser to clean the semiconductor, is characterized in that It includes the following steps: Place the semiconductor in a vacuum chamber with negative pressure, and the surface of the semiconductor is located at the focal plane position of the laser pulser; Control the laser pulse frequency of the laser pulser to be 1 Hz - 200 Hz, and the laser pulse width to be 0.1 ns - 100 ns; Control the average laser power of the laser pulser to be 100 - 1000 W, and the laser energy density to be 0.1 J / cm 2 -2 J / cm 2 .

2. The laser cleaning method for the semiconductor surface oxide according to claim 1, characterized in that, When the surface oxide of the semiconductor has a first size, control the laser pulse frequency to be 120 Hz - 200 Hz, the laser pulse width to be 80 ns - 100 ns, the average laser power to be 750 - 1000 W, and the laser energy density to be 1.8 J / cm 2 - 2.0 J / cm 2 .

3. The laser cleaning method for the semiconductor surface oxide according to claim 1, wherein When the surface oxide of the semiconductor has a second size, control the laser pulse frequency to be 70 Hz - 120 Hz, the laser pulse width to be 45 ns - 80 ns, the average laser power to be 250 - 750 W, and the laser energy density to be 0.6 J / cm 2 - 1.8 J / cm 2 .

4. The laser cleaning method for semiconductor surface oxide according to claim 1, characterized in that, When the surface oxide of the semiconductor has a third dimension, control the laser pulse frequency to be 30 Hz - 70 Hz, the laser pulse width to be 15 ns - 45 ns, the average laser power to be 150 - 250 W, and the laser energy density to be 0.3 J / cm 2 - 0.6 J / cm 2 .

5. The laser cleaning method for semiconductor surface oxide according to claim 1, characterized in that, When the surface oxide of the semiconductor has a fourth dimension, control the laser pulse frequency to be 1 Hz - 30 Hz, the laser pulse width to be 0.1 ns - 15 ns, the average laser power to be 100 - 150 W, and the laser energy density to be 0.1 J / cm 2 - 0.3 J / cm 2 .

6. The laser cleaning method of the semiconductor surface oxide according to claim 1, wherein It also includes: Control the laser scanning speed of the laser pulser on the surface of the semiconductor to be 5 mm / s - 50 mm / s.

7. The laser cleaning method for semiconductor surface oxide as described in claim 1, characterized in that, It also includes: Control the laser cleaning time of the laser pulser on the surface of the semiconductor to be 1 - 5 minutes.

8. The laser cleaning method of the semiconductor surface oxide according to claim 1, wherein, After the cleaning is completed, increase the negative pressure in the vacuum chamber to extract the suspended oxide particles in the vacuum chamber.