Gas uniformizing device for improving gas flow uniformity of plasma nitriding cavity

Abstract

The utility model discloses a gas uniformizing device for improving the gas flow uniformity of a plasma nitriding cavity, which comprises a hollow cylinder, a through hole for a support column to pass through is arranged in the middle of the hollow cylinder, gas uniformizing holes are uniformly distributed at the top of the hollow cylinder, and an extraction opening is arranged at the bottom of the hollow cylinder. And the extraction opening is connected to an exhaust port of a process cavity of the plasma nitriding machine in a sleeving manner. Compared with the prior art, the gas homogenizing device has the advantages that the uniformity of gas flow is improved: the gas homogenizing device can guide the gas flow to be uniformly distributed, so that the phenomenon that the gas flow in a local area is too fast or too slow is avoided, the gas is more uniformly distributed in a cavity, the uniformity of a plasma nitriding process is ensured, and the production yield is improved. Meanwhile, the design is simplified and the cost is reduced.

Description

Technical Field

[0001] This utility model relates to a gas equalization device, and more particularly to a gas equalization device for improving the uniformity of airflow in a plasma nitriding cavity, belonging to the field of semiconductor manufacturing technology. Background Technology

[0002] In a plasma nitriding system for semiconductor manufacturing, process gases are uniformly introduced into a vacuum chamber through a nozzle. Under radio frequency (RF) stimulation, plasma is generated. Further, the nitrogen plasma reaches the wafer surface under the influence of an electric field, reacting with exposed portions of the wafer surface to form nitrides. Excess gas and plasma are then extracted from the chamber. During this process, uneven gas flow can lead to inconsistent gas velocity and pressure on the wafer surface, ultimately resulting in poor uniformity of the formed nitride film.

[0003] Typically, the gas inside the plasma nitriding equipment chamber is extracted through vents located at the bottom or side of the chamber. Therefore, the gas flow rate is often faster near the vents and slower further away, resulting in uneven gas flow within the chamber. This affects the uniformity of the process and the yield of the final product.

[0004] Therefore, developing a gas homogenizing device to improve the uniformity of airflow in a plasma nitriding cavity and to precisely control the plasma concentration distribution has become an urgent problem for those skilled in the art. Utility Model Content

[0005] The present invention addresses the aforementioned shortcomings by providing a gas equalization device for improving the uniformity of airflow in a plasma nitriding cavity. This device is used in the plasma nitriding process cavity during semiconductor manufacturing to prevent localized airflow from being too fast or too slow, thereby improving the uniformity of nitriding.

[0006] The above-mentioned objective of this utility model is achieved through the following technical solution: a gas equalization device for improving the uniformity of airflow in a plasma nitriding cavity, comprising a hollow cylinder, a through hole in the middle of the hollow cylinder for a support column to pass through, uniformly distributed gas equalization holes at the top of the hollow cylinder, and an air extraction port at the bottom of the hollow cylinder, the air extraction port being sleeved with the exhaust port of the plasma nitriding machine's process cavity.

[0007] Furthermore, the height of the hollow cylinder is 15-25cm, preferably 20cm.

[0008] Furthermore, the diameter of the air distribution holes gradually decreases from the position away from the air extraction port to the position closer to the air extraction port, in order to alleviate the problem of excessive gas flow velocity at the air extraction port. The top of the hollow cylinder is divided into three regions: region I, region II, and region III. The size of the air distribution holes in each region is different. Region I has 50-80 large holes with a diameter of 5mm-7mm; region II has 50-70 medium holes with a diameter of 4mm-6mm; and region III has 40-60 small holes with a diameter of 2mm-4mm.

[0009] Furthermore, the hollow cylinder is cylindrical.

[0010] Furthermore, the hollow cylinder is made of any one of quartz, ceramic, or aluminum, preferably quartz.

[0011] The advantages of this utility model compared with the prior art are:

[0012] 1. Improve airflow uniformity: This air distribution device can guide the airflow to be evenly distributed, thereby avoiding the phenomenon of airflow being too fast or too slow in some areas, making the gas distribution in the cavity more uniform, ensuring the uniformity of the plasma nitriding process, and improving the production yield.

[0013] 2. Simplified design and reduced cost: This component is a consumable device that needs to be replaced regularly. Compared with the existing complex design, the structure of this utility model is simpler and is independent of the process cavity, making it easy to disassemble and replace, shortening the replacement time, and reducing the manufacturing cost, thus reducing the overall production cost. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model.

[0015] Figure 2 This is a top view of the present invention.

[0016] Figure 3 This is a schematic diagram of the structure of the present invention applied to a plasma nitriding machine.

[0017] Figure 4 This is a schematic diagram of a traditional plasma nitriding machine. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings.

[0019] like Figure 4The diagram shows a schematic of a conventional plasma nitriding machine, including a process chamber 2. A process gas inlet 3 and a matching system 4 are located at the top of the process chamber 2. An RF coil 1 is located at the upper part of the process chamber 2. A substrate 6 for supporting a wafer 5 is located at the bottom of the process chamber 2. The substrate 6 is connected to a support pillar 8. An extraction port 7 is located at the bottom of the process chamber 2. Due to the presence of the support pillar 8, the extraction port 7 is often located in an asymmetrical position within the process chamber 2. This results in a higher gas velocity near the extraction port 7 and a lower gas velocity further away from it. Furthermore, the gas flow always tends towards the extraction port 7, leading to a higher plasma concentration at the extraction port 7 than at locations further away.

[0020] like Figure 1 , Figure 2 As shown, a gas equalization device for improving the uniformity of airflow in a plasma nitriding chamber includes a hollow cylinder 108-1. The hollow cylinder 108-1 has a through hole 108-2 in the middle for a support column to pass through. The top of the hollow cylinder 108-1 has uniformly distributed gas equalization holes 108-3. The bottom of the hollow cylinder 108-1 has an exhaust port 108-4 for easy installation and positioning. The exhaust port 108-4 is sleeved on the exhaust port 107 of the plasma nitriding machine's process chamber.

[0021] like Figure 2 The image shows a top view of the gas distribution device. The diameter of the gas distribution holes gradually decreases from the position away from the air intake to the position closer to the air intake, in order to alleviate the problem of excessive gas velocity at the air intake position. The top of the hollow cylinder is divided into three regions: Region I, Region II, and Region III. The size of the gas distribution holes in each region is different. Region I has 50-80 large holes with a diameter of 5mm-7mm; Region II has 50-70 medium holes with a diameter of 4mm-6mm; and Region III has 40-60 small holes with a diameter of 2mm-4mm.

[0022] like Figure 1 As shown, the hollow cylinder 108-1 of the air-uniforming device has a height of 15cm-25cm. Too high or too low a height will affect the uniformity of the airflow. Large through holes are provided at the center of both the upper and lower ends of the air-uniforming device. The diameter of the through holes is only slightly larger than the diameter of the support column 109 to ensure that the support column can pass through. Air-uniforming holes are provided around the large through holes.

[0023] like Figure 3The diagram shows a schematic of a gas equalization device for improving the airflow uniformity of a plasma nitriding chamber, according to the present invention, applied to a plasma nitriding machine. The plasma nitriding machine includes a process chamber 102. A process gas inlet 103 and a matching system 104 are located at the top of the process chamber 102. The process gas inlet 103 is connected to the process chamber 102. An RF coil 101 is located at the upper part of the process chamber 102. The gas equalization device 108 of the present invention is located at the bottom of the process chamber 102. A substrate 106 for supporting a wafer 105 is located on the upper side of the gas equalization device 108. A pin is located on the upper part of the substrate 106 for supporting the wafer. A support column 109 is connected to the bottom of the substrate 106. The support column 109 is located at the center of the process chamber 102. An exhaust port 107 is located at the bottom of the process chamber 102. The exhaust port 108-4 of the gas equalization device is sleeved on the exhaust port 107.

[0024] During operation, the process gas (nitrogen or ammonia, preferably ammonia) enters the process chamber 102 and generates high-concentration plasma under the action of the radio frequency source (radio frequency coil 101). The vacuum pump generates a certain suction force at the exhaust port 107 to extract the tail gas that reacts with the surface of the wafer 105 in the process chamber 102. The gas equalization device of this invention is set between the lower end of the substrate and the upper end of the gas extraction port. After passing through the gas equalization device of this invention, the tail gas is extracted from the gas extraction port 108-4 / exhaust port 107.

[0025] The gas equalization device of this invention is independent of the process cavity. Without affecting the overall structure of the cavity, it can improve the airflow distribution. Furthermore, its lower end is connected to the air extraction port, which facilitates quick positioning and replacement later.

[0026] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A gas equalization device for improving the uniformity of airflow in a plasma nitriding cavity, comprising a hollow cylinder, wherein a through hole is provided in the middle of the hollow cylinder for a support column to pass through, characterized in that: The hollow cylinder has uniformly distributed air distribution holes at its top and an air extraction port at its bottom, which is connected to the exhaust port of the plasma nitriding machine's process chamber. The diameter of the air distribution holes gradually decreases from the position away from the air extraction port to the position closer to the air extraction port to alleviate the problem of excessive gas flow velocity at the air extraction port. The top of the hollow cylinder is divided into three regions: Region I, Region II, and Region III. The size of the air distribution holes in each region is different. Region I has 50-80 large holes with a diameter of 5mm-7mm; Region II has 50-70 medium holes with a diameter of 4mm-6mm; and Region III has 40-60 small holes with a diameter of 2mm-4mm.

2. The gas homogenizing device for improving the uniformity of airflow in a plasma nitriding cavity according to claim 1, characterized in that: The height of the hollow cylinder is 15-25cm.

3. The gas homogenizing device for improving the uniformity of airflow in a plasma nitriding cavity according to claim 2, characterized in that: The hollow cylinder has a height of 20cm.

4. The gas homogenizing device for improving the uniformity of airflow in a plasma nitriding cavity according to claim 1, characterized in that: The hollow cylinder is cylindrical.

5. A gas homogenizing device for improving the uniformity of airflow in a plasma nitriding cavity according to claim 1, characterized in that: The hollow cylinder is made of any one of the following materials: quartz, ceramic, or aluminum.

6. The gas homogenizing device for improving the uniformity of airflow in a plasma nitriding cavity according to claim 1, characterized in that: The hollow cylinder is made of quartz.

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