Wafer pre-cleaning device

Abstract

The utility model provides a wafer pre-cleaning device, which is characterized in that a remote plasma source is arranged outside a reaction chamber, a shielding case is arranged in the reaction chamber, pollution particles are formed on the outer surface of the shielding case, a gas pipeline is arranged in the shielding case, and the remote plasma source is communicated with the gas pipeline in the shielding case. The remote plasma source is used for generating clean gas plasmas, the gas pipeline is used for transmitting the clean gas plasmas, and the gas pipeline transmits the clean gas plasmas generated by the remote plasma source to the outer surface of the shielding case to clean contaminant particles on the outer surface of the shielding case, so that the contaminant particles are prevented from falling onto a wafer. The yield of the wafer is improved; and the clean gas plasma directly cleans the pollution particles on the outer surface of the shielding cover, the reaction chamber does not need to be opened, external pollution is prevented from being introduced into the reaction chamber, the cleaning time is far shorter than the maintenance time in the prior art, and the productivity is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to a wafer pre-cleaning device. Background Art

[0002] A chip's metal interconnects refer to the metal wires used to connect transistors, capacitors, resistors, and other components within the chip, ensuring electrical signal transmission. The metal interconnect layer is formed during the middle-of-line (MEOL) or back-end-of-line (BEOL) processes. Before forming the metal interconnect layer, metal contact holes must be formed within the wafer. After the metal contact holes are formed, residual oxides often form within them. Sputtering cleaning physically cleans the wafer surface before metal contact plugs are formed during the metal deposition process. This sputtering cleaning process typically uses argon plasma. Byproducts from this sputtering cleaning process deposit on the sidewalls and / or shielding of the reaction chamber. When these byproducts accumulate to a certain level, they eventually fall off, contaminating the wafer surface. Therefore, reaction chambers used in semiconductor device manufacturing require regular replacement and cleaning of the sidewalls and / or shielding to prevent this byproduct contamination. This regular maintenance typically requires four to eight hours of downtime to fully repair the contaminated shielding and restore the reaction chamber to operating parameters, reducing the chamber's uptime. This maintenance usually requires opening the reaction chamber to clean the reaction chamber sidewalls and replace parts. During production operations, the cleanliness of the clean room air is lower than the vacuum cleanliness of the sputtering reaction chamber, so external contaminants are easily introduced into the reaction chamber. Utility Model Content

[0003] The purpose of the utility model is to provide a wafer pre-cleaning device to solve at least one of the problems of long maintenance time of a reaction chamber and easy introduction of external contamination into the reaction chamber when replacing parts.

[0004] In order to solve the above technical problems, the utility model provides a wafer pre-cleaning device, including a reaction chamber and a remote plasma source, a shielding cover is provided in the reaction chamber, contamination particles are formed on the outer surface of the shielding cover, a gas pipeline is provided in the shielding cover, the remote plasma source is connected to the gas pipeline in the shielding cover, the remote plasma source is used to generate a cleaning gas plasma, the gas pipeline is used to transmit the cleaning gas plasma, and the gas pipeline transmits the cleaning gas plasma generated by the remote plasma source to the outer surface of the shielding cover to clean the contamination particles on the outer surface of the shielding cover.

[0005] Optionally, a wafer carrying platform is further provided in the reaction chamber, and the wafer carrying platform is located below the shielding cover. The wafer carrying platform can move up and down, and is used to carry the wafer and drive the wafer to move up and down.

[0006] Optionally, the shielding cover includes a first outer surface and a second outer surface arranged opposite to each other, the first outer surface is close to the wafer carrying platform, and the second outer surface is far away from the wafer carrying platform.

[0007] Optionally, the shielding cover includes a hollow gas pipe and a shielding cover side wall outside the gas pipe, and a first outer surface of the shielding cover is provided with a plurality of through holes penetrating the shielding cover side wall, and the through holes are used to output the clean gas plasma.

[0008] Optionally, the cleaning gas plasma is a fluorine-containing gas.

[0009] Optionally, the fluorine-containing gas includes at least one of HF, CF4, CHF3, CH2F2, CH3F, NF3, and SF6.

[0010] Optionally, the contamination particles on the outer surface of the shielding cover are located on the first outer surface.

[0011] Optionally, the contaminant particles are oxides.

[0012] Optionally, the shielding cover is semicircular and the gas pipeline is also semicircular.

[0013] Optionally, a coil is provided around the shielding cover, the coil is spiral-shaped, and the coil is used for ignition during a pre-cleaning process on the wafer surface.

[0014] In a wafer pre-cleaning device provided by the present invention, a remote plasma source is arranged outside the reaction chamber, a shielding cover is arranged in the reaction chamber, contamination particles are formed on the outer surface of the shielding cover, a gas pipeline is arranged in the shielding cover, the remote plasma source is connected to the gas pipeline in the shielding cover, the remote plasma source is used to generate a cleaning gas plasma, the gas pipeline is used to transmit the cleaning gas plasma, the gas pipeline transmits the cleaning gas plasma generated by the remote plasma source to the outer surface of the shielding cover to clean the contamination particles on the outer surface of the shielding cover, thereby preventing the contamination particles on the outer surface of the shielding cover from falling onto the wafer, thereby improving the yield of the wafer; and the cleaning gas plasma generated by the remote plasma source in the utility model is transmitted to the outer surface of the shielding cover to directly clean the contamination particles on the outer surface of the shielding cover, without opening the reaction chamber, thereby avoiding the introduction of external contamination into the reaction chamber, and the time for cleaning the contamination particles in the utility model is much shorter than the time for maintaining the shielding cover in the prior art, thereby saving the maintenance time of the reaction chamber and improving productivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Those skilled in the art will appreciate that the accompanying drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0016] Figure 1 It is a structural schematic diagram of a wafer pre-cleaning device in which contamination particles are formed on the surface of a shielding cover during pre-cleaning of the wafer surface according to an embodiment of the present invention.

[0017] Figure 2 It is a structural schematic diagram of a wafer pre-cleaning device after contamination particles are formed on the surface of a shielding cover according to an embodiment of the present utility model.

[0018] Figure 3 It is a schematic structural diagram of a wafer pre-cleaning device for cleaning a reaction chamber according to an embodiment of the present invention.

[0019] Figure 4 It is a schematic structural diagram of a wafer pre-cleaning device after the reaction chamber is cleaned according to an embodiment of the present invention.

[0020] In the attached figure:

[0021] 10-reaction chamber; 11-remote plasma source; 12-shielding cover; 12a-gas pipeline; 12b-first outer surface; 12c-through hole; 12d-second outer surface; 13-contaminated particles; 14-coil; 15-wafer; 16-wafer carrier; 17-cleaning gas plasma. DETAILED DESCRIPTION

[0022] To further clarify the objectives, advantages, and features of the present invention, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are highly simplified and not drawn to scale, and are intended solely to facilitate and clearly illustrate the objectives of the embodiments of the present invention. Furthermore, the structures shown in the drawings are often portions of the actual structures. In particular, different drawings may require different emphases and may use different scales.

[0023] As used in this utility model, the singular forms "a", "an", and "the" include plural objects, the term "or" is generally used to include the meaning of "and / or", the term "several" is generally used to include the meaning of "at least one", and the term "at least two" is generally used to include the meaning of "two or more". In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features specified as "first", "second", and "third" can explicitly or implicitly include one or at least two of the features. In addition, as used in this utility model, an element is provided on another element, which generally only indicates that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the connection, coupling, cooperation or transmission between the two elements can be direct or indirect through an intermediate element, and should not be understood to indicate or imply the spatial positional relationship between the two elements, that is, one element can be in any orientation such as inside, outside, above, below, or to the side of another element, unless the content clearly indicates otherwise. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0024] Figure 1 It is a structural schematic diagram of a wafer pre-cleaning device in which contamination particles are formed on the surface of a shielding cover during pre-cleaning of the wafer surface according to an embodiment of the present invention. Figure 2 It is a structural schematic diagram of a wafer pre-cleaning device after contamination particles are formed on the surface of a shielding cover according to an embodiment of the present utility model. Figure 3 It is a schematic structural diagram of a wafer pre-cleaning device for cleaning a reaction chamber according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the structure of the wafer pre-cleaning device after the reaction chamber is cleaned according to the embodiment of the present invention. Figures 1-4As shown, the present invention provides a wafer pre-cleaning device for removing residual oxides in the contact holes of a wafer 15. When an argon (Ar) sputtering pre-cleaning process is used to remove the residual oxides in the contact holes of the wafer 15, contamination particles 13 are formed on the outer surface of the shielding cover 12. When the contamination particles 13 on the outer surface of the shielding cover 12 accumulate to a certain extent, they will fall off to the surface of the wafer 15 and contaminate the wafer 15. The wafer pre-cleaning device includes a reaction chamber 10 and a remote plasma source (RPS) 11 located outside the reaction chamber 10. A shielding cover 12 is provided in the reaction chamber 10. Contamination particles 13 are formed on the outer surface of the shielding cover 12. A gas conduit 12a is provided in the shielding cover 12. The gas conduit 12a and the shielding cover 12 have the same shape. The shielding cover 12 is semicircular, and the gas conduit 12a is also semicircular. The remote plasma source 11 is connected to the gas pipe 12a in the shielding cover 12. The remote plasma source 11 is used to generate clean gas plasma, and the gas pipe 12a is used to transport clean gas plasma. The gas pipe 12a transmits the clean gas plasma generated by the remote plasma source 11 to the outer surface of the shielding cover 12 to clean the contaminated particles 13 on the outer surface of the shielding cover 12.

[0025] Please continue to refer to Figure 1 A wafer carrier 16 is also provided in the reaction chamber 10. The wafer carrier 16 is located below the shielding cover 12 and can move up and down. The wafer carrier 16 is used to carry the wafer 15 and drive the wafer 15 to move up and down. When performing the wafer pre-cleaning process, the wafer carrier 16 drives the wafer 15 to rise until the wafer carrier 16 contacts the shielding cover 12 to form a closed space. When performing the wafer pre-cleaning process, argon ions bombard the surface of the wafer 15. After the residual oxide on the surface of the wafer 15 is bombarded, the pollutant particles generated are reflected on the outer surface of the shielding cover in the closed space, thereby preventing the pollutant particles from being reflected to other places.

[0026] Please continue to refer to Figure 3The shielding cover 12 includes a first outer surface 12b and a second outer surface 12d arranged opposite to each other, the first outer surface 12b is close to the wafer carrier 16, and the second outer surface 12d is away from the wafer carrier 16. The shielding cover 12 includes a hollow gas pipe 12a and a shielding cover side wall outside the gas pipe 12a. The first outer surface 12b of the shielding cover is provided with a plurality of through holes 12c penetrating the shielding cover side wall, and the through holes 12c are used to output the cleaning gas plasma. The cleaning gas plasma is a fluorine-containing gas. The fluorine-containing gas includes at least one of HF, CF4, CHF3, CH2F2, CH3F, NF3, and SF6. The contamination particles 13 on the outer surface of the shielding cover 12 are located on the first outer surface 12b. The contamination particles 13 are, for example, oxides, which are by-products in the wafer pre-cleaning process. The fluorine ions (F - ) The plasma undergoes an oxidation reaction with the contaminated particles 13 to remove the contaminated particles 13 on the first outer surface 12b of the shielding cover, thereby preventing the contaminated particles 13 on the first outer surface 12b of the shielding cover from falling off to the surface of the wafer 15 during the pre-cleaning process, thereby contaminating the wafer 15.

[0027] Please refer to Figures 1-4 Argon gas is also introduced into the reaction chamber 10 for RPS ignition. Specifically, a spiral coil 14 is formed around the shield 12. This coil 14 is used to ignite the wafer 15 during the pre-cleaning process, ionizing the argon gas into argon ions that bombard the wafer surface to remove residual oxides within the contact holes.

[0028] The utility model also provides a self-cleaning method for a wafer pre-cleaning device, comprising:

[0029] A wafer pre-cleaning device is provided, the wafer pre-cleaning device comprising a shielding cover, and contamination particles are formed on a first outer surface of the shielding cover;

[0030] A self-cleaning process of the wafer pre-cleaning device is performed, and a remote plasma source is started. The remote plasma source generates a cleaning gas plasma, and the cleaning gas plasma is transmitted to the gas pipeline of the shielding cover and output through the through hole of the first outer surface of the shielding cover. The cleaning gas plasma reacts with the contamination particles on the first outer surface of the shielding cover to remove the contamination particles on the first outer surface of the shielding cover.

[0031] Specifically, such as Figure 1As shown, a wafer 15 is provided. The wafer 15 can be a semiconductor substrate made of any semiconductor material suitable for semiconductor devices (such as Si, SiC, SiGe, etc.). In other embodiments, the wafer 15 can also be various composite substrates such as silicon on insulator (SOI) and silicon germanium on insulator. Those skilled in the art understand that the substrate is not subject to any restrictions and can be selected according to actual applications. Various device (not limited to semiconductor devices) components can be formed in the substrate (not shown in the figure). The wafer 15 may also have other layers or components formed thereon, such as: gate structures, contact holes, dielectric layers, metal connections and through-holes, etc. In this embodiment, a contact hole penetrating the dielectric layer is formed on the wafer 15, and a dielectric layer remains in the contact hole. The dielectric layer is, for example, an oxide, and the residue in the contact hole is removed before the contact plug is filled in the contact hole. As shown Figure 1 As shown, the wafer 15 is located on the wafer carrier 16, the wafer carrier 16 is raised, and the wafer carrier 16 contacts the shielding cover 12. A surface cleaning process is performed on the wafer 15, and the coil 14 is ignited. The argon gas is ionized into argon ions (Ar+). The argon ions bombard the surface of the contact hole of the wafer 15, and the residue in the contact hole will be sputtered to the first outer surface 12b of the shielding cover to form contamination particles. Since the shielding cover 12 contacts the wafer carrier 16 to form a closed space, contamination particles 13 are formed only on the first outer surface 12b of the shielding cover in the closed space. When the contamination particles 13 on the first outer surface 12b of the shielding cover accumulate to a certain extent, when the wafer 15 performs a pre-cleaning process, the contamination particles 13 on the first outer surface 12b of the shielding cover will fall off to the surface of the wafer 15, causing surface contamination of the wafer 15. Therefore, it is necessary to clean the contamination particles 13 on the first outer surface 12b of the shielding cover.

[0032] like Figure 2 As shown, after the pre-cleaning process of the wafer 15 is completed, the wafer carrier 16 drives the wafer 15 downward and transfers the wafer 15 out of the reaction chamber 10. At this time, a large number of contamination particles 13 are formed on the first outer surface 12b of the shielding cover of the reaction chamber 10.

[0033] like Figure 3 As shown, the self-cleaning process of the wafer pre-cleaning device is performed, the remote plasma source 11 is started, the remote plasma source 11 generates a cleaning gas plasma 17, and the cleaning gas plasma 17 is transmitted to the gas pipeline 12a of the shield cover and output through the through hole 12c on the first outer surface of the shield cover. The cleaning gas plasma 17 reacts with the contamination particles 13 on the first outer surface of the shield cover to remove the contamination particles 13 on the first outer surface of the shield cover. Figure 4As shown, the contamination particles 13 on the first outer surface of the shield are removed. The cleaning time of the self-cleaning process of the wafer pre-cleaning device is determined by the amount of contamination particles 13 on the first outer surface 12b of the shield, which is not limited in this embodiment.

[0034] The self-cleaning process cycle of the wafer pre-cleaning device is, for example, to complete the surface pre-cleaning process for every 25 wafers. The self-cleaning process cycle of the wafer pre-cleaning device can also be determined based on the accumulation rate of contaminant particles 13 on the first outer surface 12b of the shielding cover, and this is not limited in this embodiment. After the surface pre-cleaning process of 25 wafers 15 is completed, the wafer pre-cleaning device performs a self-cleaning process to remove the contaminant particles 13 on the first outer surface 12b of the shielding cover, thereby improving the yield of the wafers 15. Moreover, the self-cleaning method of the wafer pre-cleaning device provided in this embodiment does not require opening the reaction chamber 10, will not destroy the vacuum state within the reaction chamber 10, and will not introduce external contaminants into the reaction chamber 10. Although the process time of the self-cleaning method of the wafer pre-cleaning device provided in this embodiment is determined by the number of contaminated particles 13 on the first outer surface of the shielding cover, it is much shorter than the four to eight hours of downtime required to completely repair the contaminated shielding cover in the prior art. Therefore, the self-cleaning method of the wafer pre-cleaning device provided in this embodiment saves time costs, avoids contamination of the reaction chamber 10, and improves the yield of the wafer.

[0035] In summary, it can be seen that in a wafer pre-cleaning device provided by an embodiment of the present invention, a remote plasma source is arranged outside the reaction chamber, a shielding cover is arranged in the reaction chamber, contamination particles are formed on the outer surface of the shielding cover, a gas pipeline is arranged in the shielding cover, the remote plasma source is connected to the gas pipeline in the shielding cover, the remote plasma source is used to generate a cleaning gas plasma, and the gas pipeline is used to transmit the cleaning gas plasma. The gas pipeline transmits the cleaning gas plasma generated by the remote plasma source to the outer surface of the shielding cover to clean the contamination particles on the outer surface of the shielding cover, thereby preventing the contamination particles on the outer surface of the shielding cover from falling onto the wafer, thereby improving the yield of the wafer; and the cleaning gas plasma generated by the remote plasma source in the utility model is transmitted to the outer surface of the shielding cover to directly clean the contamination particles on the outer surface of the shielding cover, without opening the reaction chamber, thereby avoiding the introduction of external contamination into the reaction chamber, and the time for cleaning the contamination particles in the utility model is much shorter than the time for maintaining the shielding cover in the prior art, thereby saving the maintenance time of the reaction chamber and improving productivity.

[0036] Furthermore, it should be recognized that although the present invention has been disclosed above with reference to preferred embodiments, the above embodiments are not intended to limit the present invention. Any person skilled in the art will be able to utilize the above-disclosed technical content to make numerous possible variations and modifications to the present invention, or to modify the present invention into equivalent embodiments with equivalent variations, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. A wafer pre-cleaning device, characterized in that: The invention comprises a reaction chamber and a remote plasma source, wherein a shielding cover is provided in the reaction chamber, contamination particles are formed on the outer surface of the shielding cover, a gas pipeline is provided in the shielding cover, the remote plasma source is connected to the gas pipeline in the shielding cover, the remote plasma source is used to generate a cleaning gas plasma, the gas pipeline is used to transmit the cleaning gas plasma, and the gas pipeline transmits the cleaning gas plasma generated by the remote plasma source to the outer surface of the shielding cover to clean the contamination particles on the outer surface of the shielding cover.

2. The wafer pre-cleaning device according to claim 1, characterized in that: A wafer carrying platform is also provided in the reaction chamber. The wafer carrying platform is located below the shielding cover and can move up and down. The wafer carrying platform is used to carry the wafer and drive the wafer to move up and down.

3. The wafer pre-cleaning device according to claim 2, characterized in that: The shielding cover includes a first outer surface and a second outer surface that are opposite to each other. The first outer surface is close to the wafer carrying platform, and the second outer surface is far away from the wafer carrying platform.

4. The wafer pre-cleaning device according to claim 3, characterized in that: The shielding cover includes a hollow gas pipeline and a shielding cover side wall outside the gas pipeline. The first outer surface of the shielding cover is provided with a plurality of through holes penetrating the shielding cover side wall. The through holes are used to output the cleaning gas plasma.

5. The wafer pre-cleaning device according to claim 1 or 4, characterized in that: The cleaning gas plasma is a fluorine-containing gas.

6. The wafer pre-cleaning device according to claim 5, characterized in that: The fluorine-containing gas includes one of HF, CF4, CHF3, CH2F2, CH3F, NF3, and SF6.

7. The wafer pre-cleaning device according to claim 3, characterized in that: The contamination particles on the outer surface of the shielding cover are located on the first outer surface.

8. The wafer pre-cleaning device according to claim 1 or 7, characterized in that: The pollution particles are oxides.

9. The wafer pre-cleaning device according to claim 1, characterized in that: The shielding cover is semicircular, and the gas pipeline is semicircular.

10. The wafer pre-cleaning device according to claim 1, wherein: A coil is arranged around the shielding cover, and the coil is spiral-shaped. The coil is used for ignition during a pre-cleaning process performed on the wafer surface.

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