Source coating method

Abstract

The invention belongs to the technical field of semiconductor wafer manufacturing, and discloses a source coating method which comprises the following steps: providing a wafer; cleaning and spin-drying the wafer and then placing the wafer in a tray; carrying out ultrasonic atomization treatment on the liquid source to atomize the liquid source into micron-sized liquid drops; and introducing current-carrying gas, and pushing the liquid drops to be deposited on the wafer by the current-carrying gas. According to the source coating method, the liquid source is atomized into the micron-sized liquid drops through the ultrasonic atomization treatment, and then the liquid drops are deposited on the wafer through the current-carrying gas, so that the coating uniformity is effectively improved; manual coating is not needed, and the automation degree of coating is also improved; therefore, the problem of hair falling of the brush or the writing brush is avoided and the reduction of the wafer yield is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor wafer manufacturing, and in particular to a source coating method. Background Art

[0002] The diffusion process during wafer processing refers to the addition of trivalent or pentavalent elements to the surface of the silicon wafer to change the conductivity type and resistivity of the silicon wafer. In the prior art, a brush or a hairbrush is usually used to apply such diffusion sources. That is, first use a brush to dip the diffusion source and apply it to the wafer. Then, the wafer rotates to evenly distribute the diffusion source on the wafer. Finally, the wafer is heated to complete the source coating. This coating method will cause the concentration of the diffusion source to be high in some areas of the wafer surface and low in some areas. Secondly, if the brush or the hairbrush falls off, it will also cause the wafer yield to decrease. In addition, this coating method has a low degree of automation and low coating efficiency. Summary of the invention

[0003] The purpose of the present invention is to provide a coating source method, aiming to solve the problem of uneven coating in existing coating methods and low wafer yield after coating. The coating source method can effectively improve the coating quality, improve the coating uniformity, and ensure that the wafer has a good yield.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] Source coating methods, including:

[0006] providing a wafer;

[0007] The wafer is cleaned, dried and placed in a tray;

[0008] Ultrasonic atomization is performed on the liquid source to atomize it into micron-sized droplets;

[0009] A carrier gas is introduced, and the carrier gas pushes the droplets to be deposited on the wafer.

[0010] Preferably, the ultrasonic atomization treatment is carried out by using an ultrasonic atomization component, which includes a liquid source component, an atomization component and a nozzle component. The liquid source component is connected to the atomization component through a pipeline, and the nozzle component is connected to the atomization component. The atomization component can atomize the liquid source in the liquid source component, so that the liquid source after the atomization treatment is sprayed onto the surface of the wafer through the nozzle component.

[0011] Preferably, the atomizing component includes a shell, an ultrasonic component and an air supply component. The liquid source component passes through the shell and is connected to the ultrasonic cavity in the shell through a pipe. The air supply component is arranged between the outlet of the ultrasonic cavity and the nozzle component. The ultrasonic component is installed on the shell and performs ultrasonic atomization treatment on the liquid source in the ultrasonic cavity.

[0012] Preferably, the nozzle member comprises a guide nozzle, the longitudinal section of the guide nozzle is conical, the small end of the guide nozzle is connected to the atomizing member, and the large end of the guide nozzle faces the wafer.

[0013] Preferably, the nozzle member comprises a guide nozzle, the longitudinal section of the guide nozzle is conical, the large end of the guide nozzle is connected to the atomizing member, and the small end of the guide nozzle faces the wafer.

[0014] Preferably, the nozzle member also includes a diffusion tube, which is connected to one end of the guide nozzle away from the atomizing member, and includes a main tube connected to the guide nozzle and a plurality of branch tubes evenly arranged on the outer periphery of the main tube and connected to the main tube, and a plurality of diffusion holes evenly distributed along the axial direction are provided on the side of the branch tube close to the wafer.

[0015] Preferably, a plurality of the ultrasonic atomization assemblies are provided, and the plurality of the ultrasonic atomization assemblies are evenly distributed above the wafer.

[0016] Preferably, after the droplets are deposited on the wafer, the tray is driven to rotate by a power component to cause the wafer to rotate.

[0017] Preferably, after the wafer has completed its rotation, the wafer is heated and dried.

[0018] Beneficial effects of the present invention: The source coating method provided by the present invention performs ultrasonic atomization treatment on the liquid source to atomize it into micron-sized droplets, and then deposits the droplets onto the wafer through a carrier gas, thereby effectively improving the coating uniformity, thereby improving the coating quality and ensuring that the wafer has a good yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flow chart of a source coating method provided by an embodiment of the present invention;

[0020] Figure 2 is a schematic diagram of the overall structure of a coating source device provided by an embodiment of the present invention;

[0021] Figure 3 It is a structural schematic diagram of a guide nozzle according to an implementation mode provided by an embodiment of the present invention;

[0022] Figure 4 It is a structural schematic diagram of a guide nozzle according to another implementation mode provided by an embodiment of the present invention;

[0023] Figure 5 It is a schematic diagram of the structure of a diffusion tube provided in an embodiment of the present invention.

[0024] In the figure:

[0025] 100, base;

[0026] 200. Diffusion source after atomization;

[0027] 300, support frame;

[0028] 410, liquid source component; 420, atomizing component; 421, ultrasonic component; 422, gas supply component; 430, nozzle component; 431, guide nozzle; 432, diffusion tube; 4321, main tube; 4322, branch tube; 43221, diffusion hole; 500, wafer; 600, second threaded component; 700, protective ring cover. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0030] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0032] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0033] This embodiment provides a coating source method, which aims to solve the problem of uneven coating in existing coating methods and low wafer yield after coating. The coating source method can effectively improve the coating quality, improve the coating uniformity, and ensure that the wafer has a good yield.

[0034] See also Figure 1 , the source coating method comprises the following steps:

[0035] S1. providing a wafer 500;

[0036] S2, cleaning and drying the wafer 500 and placing it in a tray;

[0037] S3, performing ultrasonic atomization treatment on the liquid source to atomize it into micron-sized droplets;

[0038] S4 , introducing a carrier gas, which pushes the droplets to deposit onto the wafer 500 .

[0039] The above-mentioned coating source method, through ultrasonic atomization treatment of the liquid source to atomize it into micron-sized droplets, then deposits the droplets onto the wafer 500 through a carrier gas, effectively improves the coating uniformity, thereby improving the coating quality and ensuring that the wafer 500 has a good yield.

[0040] In the prior art, when coating the source, the wafer 500 will rotate at a relatively high speed, and 90% of the diffusion source will be thrown out and wasted during the rotation process, and the utilization rate of the diffusion source is only about 10%. In this embodiment, after the droplets are deposited on the wafer 500, the tray is driven to rotate by the power part to make the wafer 500 rotate. After the source coating is completed, the wafer 500 is rotated at a relatively low speed, so that the droplets on the surface of the wafer 500 are further uniformed, and at the same time, unnecessary waste of the diffusion source is avoided, thereby improving the utilization rate.

[0041] Furthermore, after the wafer 500 has completed its rotation, the wafer 500 is heated and dried to prepare for other subsequent process treatments. Optionally, during drying, the drying device is an infrared drying device with forced exhaust.

[0042] In this embodiment, the source coating method is performed using a source coating device, see Figure 2-Figure 5The coating source device includes a base 100, a supporting assembly, a support frame 300 and an ultrasonic atomization assembly. The supporting assembly is installed on the base 100, and the supporting assembly includes a tray, which is used to adsorb the wafer 500; the support frame 300 is slidably arranged on the base 100 along a first direction; the ultrasonic atomization assembly is slidably arranged on the support frame 300 along a second direction, and the ultrasonic atomization assembly is located above the wafer 500, and the ultrasonic atomization assembly includes a liquid source component 410, an atomization component 420 and a nozzle component 430. The liquid source component 410 is connected to the atomization component 420 through a pipeline, and the nozzle component 430 is connected to the atomization component 420. The atomization component 420 can perform ultrasonic atomization treatment on the liquid source in the liquid source component 410, so that the liquid source after ultrasonic atomization treatment is sprayed to the surface of the wafer 500 through the nozzle component 430.

[0043] When coating the source, the support frame 300 can be slid along the first direction to adjust the distance between the ultrasonic atomization assembly and the wafer 500 as needed, and the ultrasonic atomization assembly can be slid along the second direction to adjust the position of the nozzle component 430 above the wafer 500, so that the coating effect is more uniform; the atomization component 420 atomizes the liquid source in the liquid source component 410, and the atomized liquid source is sprayed onto the surface of the wafer 500 through the nozzle component 430, thereby realizing automatic coating and ensuring a high coating efficiency.

[0044] Specifically, the atomizing element 420 includes a shell, an ultrasonic element 421 and an air supply element 422. The liquid source element 410 passes through the shell and is connected to the ultrasonic cavity in the shell through a pipeline. The air supply element 422 is arranged between the outlet of the ultrasonic cavity and the nozzle element 430. The ultrasonic element 421 is installed on the shell and performs ultrasonic atomization on the liquid source in the ultrasonic cavity. By setting the shell, the shell protects the ultrasonic cavity and the air supply element 422 from external impact; the air supply element 422 is arranged between the outlet of the ultrasonic cavity and the nozzle element 430, so as to facilitate the ejection of the atomized liquid source from the nozzle element 430.

[0045] Optionally, the nozzle member 430 includes a guide nozzle 431, the longitudinal section of the guide nozzle 431 is conical, the small end of the guide nozzle 431 is connected to the atomizing member 420, and the large end of the guide nozzle 431 faces the wafer 500, see Figure 2 , the atomized diffusion source 200 is ejected radially or linearly. Alternatively, the large end of the guide nozzle 431 is connected to the atomizing element 420, and the small end of the guide nozzle 431 faces the wafer 500, see Figure 3 , the atomized diffusion source 200 is sprayed radially or linearly. In actual design, the large end or small end of the guide nozzle 431 can be set to face the wafer 500 according to the size of the wafer 500 (such as 8 inches or 12 inches), and multiple vertical or inclined spraying branch pipes can be set in the guide nozzle 431 according to actual needs to determine the spraying mode of the diffusion source.

[0046] Preferably, the nozzle member 430 further includes a diffusion tube 432, which is connected to one end of the guide nozzle 431 away from the atomizing member 420, and includes a main tube 4321 connected to the guide nozzle 431 and a plurality of branch tubes 4322 evenly arranged on the periphery of the main tube 4321 and connected to the main tube 4321, and a plurality of diffusion holes 43221 evenly distributed along the axial direction are provided on the side of the branch tube 4322 close to the wafer 500. When applying the source, the atomized liquid source enters the main tube 4321 through the guide nozzle 431, and then enters the decomposition tube through the main tube 4321, and is sprayed to the wafer 500 through the dispersion hole, thereby improving the distribution uniformity of the diffusion source from the center to the edge of the wafer 500.

[0047] In this embodiment, multiple ultrasonic atomization assemblies may be provided, and the multiple ultrasonic atomization assemblies are evenly distributed above the wafer 500. For example, three ultrasonic atomization assemblies are provided, and the three ultrasonic atomization assemblies are evenly distributed along the circumference of the wafer 500. The length of the branch pipe 4322 is set as required, so that the dispersion pipes are evenly distributed on the top of the wafer 500 as much as possible, ensuring that the diffusion source is deposited on the entire surface of the wafer 500. In other embodiments, the ultrasonic atomization assemblies may also be set to four or five, etc., which can be set as required.

[0048] Optionally, a guide groove is provided on the side of the base 100, and a plurality of first threaded holes are provided at intervals along a first direction at the bottom of the guide groove, and the support frame 300 can be locked in the first threaded hole by a first threaded member; a plurality of second threaded holes are provided on the support frame 300 at intervals along a second direction, and the ultrasonic atomization assembly can be locked in the second threaded hole by a second threaded member 600. This arrangement facilitates the adjustment of the position of the support frame 300 and the ultrasonic atomization assembly, and is also convenient for assembly and disassembly.

[0049] To protect the wafer 500 from external contamination, the supporting assembly further includes a protective ring cover 700 , which is mounted on the base 100 and spaced around the tray. The height of the protective ring cover 700 is greater than the height of the tray.

[0050] Preferably, the coating source device further comprises a robot, which is disposed on the base 100 and located on one side of the supporting assembly for transferring the wafer 500 .

[0051] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A coating source method, characterized in that: include: Providing a wafer (500); The wafer (500) is cleaned and dried and then placed in a tray; Ultrasonic atomization is performed on the liquid source to atomize it into micron-sized droplets; A carrier gas is introduced, and the carrier gas pushes the droplets to deposit onto the wafer (500).

2. The coating source method according to claim 1, characterized in that: The ultrasonic atomization treatment is performed by using an ultrasonic atomization component, which includes a liquid source component (410), an atomization component (420) and a nozzle component (430). The liquid source component (410) is connected to the atomization component (420) via a pipeline, and the nozzle component (430) is connected to the atomization component (420). The atomization component (420) can perform ultrasonic atomization treatment on the liquid source in the liquid source component (410), so that the liquid source after ultrasonic atomization treatment is sprayed onto the surface of the wafer (500) via the nozzle component (430).

3. The coating source method according to claim 2, characterized in that: The atomizing element (420) comprises a shell, an ultrasonic element (421) and an air supply element (422); the liquid source element (410) passes through the shell and is connected to the ultrasonic cavity in the shell through a pipeline; the air supply element (422) is arranged between the outlet of the ultrasonic cavity and the nozzle element (430); the ultrasonic element (421) is installed on the shell and performs ultrasonic atomization processing on the liquid source in the ultrasonic cavity.

4. The coating source method according to claim 2, characterized in that: The nozzle member (430) comprises a guide nozzle (431), the longitudinal section of the guide nozzle (431) is conical, the small end of the guide nozzle (431) is connected to the atomizing member (420), and the large end of the guide nozzle (431) faces the wafer (500).

5. The source coating method according to claim 2, characterized in that: The nozzle member (430) comprises a guide nozzle (431), the longitudinal section of the guide nozzle (431) is conical, the large end of the guide nozzle (431) is connected to the atomizing member (420), and the small end of the guide nozzle (431) faces the wafer (500).

6. The source coating method according to claim 4 or 5, characterized in that: The nozzle member (430) further comprises a diffusion tube (432), wherein the diffusion tube (432) is connected to one end of the guide nozzle (431) away from the atomizing member (420), and the diffusion tube (432) comprises a main tube (4321) connected to the guide nozzle (431) and a plurality of branch tubes (4322) evenly arranged on the periphery of the main tube (4321) and connected to the main tube (4321), and a plurality of diffusion holes (43221) evenly distributed along the axial direction are provided on a side of the branch tube (4322) close to the wafer (500).

7. The source coating method according to claim 2, characterized in that: A plurality of the ultrasonic atomization components are provided, and the plurality of the ultrasonic atomization components are evenly distributed above the wafer (500).

8. The source coating method according to claim 1, characterized in that: After the liquid droplets are deposited on the wafer (500), the tray is driven to rotate by a power component, so that the wafer (500) rotates.

9. The source coating method according to claim 8, characterized in that: After the wafer (500) has completed its self-rotation, the wafer (500) is heated and dried.

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