TW202025292A - Air-intake pipe connecting device and air-intake unit for plasma etching containing the same avoiding the metal contamination of the wafer caused by the corrosion of the etching gas pipeline - Google Patents

Abstract

The present invention discloses an air-intake pipe connecting device and an air-intake unit for plasma etching containing the same. The air-intake pipe connecting device includes a tubular body and a corrosion-resistant seal member disposed in the tubular body; the etching gas pipeline and the gas pipeline fittings respectively extend from the two ends of the tubular body and are connected, and the connection is surrounded and sealed by the corrosion-resistant seal; the two ends of the tubular body are respectively fixed with the etching gas pipeline and the gas pipeline fittings by welding. After adopting the present invention, water vapor contacts the corrosion-resistant seal member when entering the etching gas pipeline, and it will not touch the welded seam welded on both sides of the outside of the air-intake pipe connecting device, thus avoiding the corrosion of welded seam in the etching gas pipeline, extending the service life of the etching gas pipeline, effectively avoiding the metal contamination of the wafer caused by the corrosion of the etching gas pipeline, and improving the quality of the product.

Description

Air intake pipeline connecting device and air intake unit for plasma etching containing same

The invention relates to the technical field of plasma etching, in particular to an air intake pipeline connecting device and an air intake unit for plasma etching containing the same.

In the existing plasma etching technology, inductively coupled plasma (ICP, Inductive Coupled Plasma) and capacitive coupling (CCP) type etching machines are often introduced Cl2, COS, HBr, SiCl4 and other corrosive gases to the silicon wafer (silicon ) Perform etching.

These corrosive gases need to enter the reaction chamber through a gas line metal pipe. At present, most gas pipeline materials use stainless steel pipes such as SST316L. When the reaction chamber is opened, water vapor in the atmosphere will enter the exposed SST316L pipeline.

Therefore, after each cavity is opened, the water vapor will stay in the gas pipeline and is difficult to volatilize. Water vapor will corrode the weld when it encounters corrosive gas. Studies have shown that when the water vapor concentration exceeds 0.5PPM, the welds of the metal pipes will be corroded; when the water vapor concentration is greater than 100PPM, the corrosion points are visible to the naked eye. The corrosion of the weld will bring out the heavy metals such as Cr and Mn in the stainless steel and deposit them on the wafer, causing metal contamination to the wafer. The current common practice is to replace the gas pipeline every time the cavity is opened, which is costly and time-consuming to maintain. Therefore, there is no solution that can effectively avoid the corrosion of the welds of gas pipelines by water vapor.

The object of the present invention is to provide an air inlet pipe connecting device and an air inlet unit for plasma etching containing the same, so as to solve the problem that water vapor cannot effectively avoid corrosion of etching gas pipeline welds in the prior art.

In order to achieve the above objective, the present invention provides an air inlet pipe connection device for connecting an etching gas pipeline and a gas pipe joint on the etching reaction chamber, wherein the air inlet pipe connection device includes a tubular body and is arranged in the tubular body. Corrosion-resistant seals in the body; the etching gas pipeline and the gas pipeline joints extend from the two ends of the tubular body and are connected, and the joint is surrounded and sealed by the corrosion-resistant seal; the two ends of the tubular body are respectively connected with the etching The gas pipeline and the gas pipeline joint are fixed by welding.

In the above-mentioned air inlet pipe connecting device, the tubular body is provided with a first annular groove for embedding the corrosion-resistant seal.

In the above-mentioned air inlet pipe connecting device, the outer wall of the joint of the etching gas pipe and the gas pipe joint is combined into a second annular groove for embedding the corrosion-resistant seal.

In the above-mentioned air inlet pipe connecting device, the etching gas pipeline and the gas pipeline joint are respectively provided with a first annular outward extending portion and a second annular outward extending portion on the outer wall away from the butting place; the first annular shape The outward extending portion and the second annular outward extending portion are combined to form a third annular groove for inserting into the tubular body.

In the above-mentioned air inlet pipe connecting device, the outer circumference of the tubular body is aligned with the outer circumference of the first annular outward extending portion and the second annular outward extending portion; the weld formed by welding is located on the tubular body and the first The outer peripheral position of the joint of the annular outward extension part and the second annular outward extension part, so that the weld is away from the etching gas pipeline and the body of the gas pipeline joint.

In the above-mentioned air inlet pipe connecting device, a third annular outward extending portion and a fourth annular outward extending portion are respectively provided on both sides of the tubular body; the third annular outward extending portion and the fourth annular outward extending portion Do not align with the outer peripheries of the first annular outward extending portion and the second annular outward extending portion.

In the above-mentioned air inlet pipe connecting device, the material of the tubular body is stainless steel.

In the above-mentioned air inlet pipe connecting device, the material of the corrosion-resistant seal is Teflon or polyimide.

In the above-mentioned air inlet pipe connection device, the gas pipe joint is a VCR joint.

The present invention also provides an air intake unit for plasma etching, wherein the air intake unit includes: an etching gas source for supplying etching gas; an etching gas pipeline connected to the etching gas source; and is arranged in the etching reaction chamber The upper gas pipeline joint and the above-mentioned air inlet pipeline connection device are used to connect the etching gas pipeline and the gas pipeline joint.

Compared with the prior art, the present invention has the following beneficial effects: In the existing plasma etching process, after the air inlet pipe connection device provided by the present invention and the air inlet unit for plasma etching containing it are used, the water vapor enters the etching gas pipeline and touches the corrosion-resistant seal. The parts will not come into contact with the welds welded on both sides of the inlet pipe connection device, thus avoiding the corrosion of the welds of the original etching gas pipeline, prolonging the service life of the etching gas pipeline, and further effectively avoiding the etching gas The chip metal contamination caused by pipeline corrosion improves the quality of the product.

The present invention will be further described below through specific embodiments with reference to the accompanying drawings. These embodiments are only used to illustrate the present invention and do not limit the protection scope of the present invention.

As shown in FIG. 1, it is a schematic structural diagram of an existing embodiment of the etching reaction chamber 6 and the air inlet unit 22 thereof. Part of the etching gas in the main gas line is split by the flow divider 4 and then transported through the first gas line 1 and the second gas line 2, and then enters the etching reaction chamber 6 through the central air inlet of the etching reaction chamber 6 Inside; another part of the etching gas is directly transported through the third gas pipeline 3, and then enters the etching reaction chamber 6 through the peripheral air inlet of the etching reaction chamber 6. The first gas pipeline 1, the second gas pipeline 2 and the third gas pipeline 3 jointly constitute the etching gas pipeline 15. The tuning gas pipeline 5 for transporting tuning gas is simultaneously connected with the first gas pipeline 1, the second gas pipeline 2 and the third gas pipeline 3 to mix the tuning gas into the etching gas, and then transport it into the etching reaction chamber 6 . At present, most of the etching gas pipelines 15 are easy to use, cheap SST316L stainless steel and other pipes that are not easily corroded. However, this design also brings the following problems: every time the etching reaction chamber 6 is opened, The etching gas pipeline 15 directly connected to the reaction chamber 6 will be directly exposed to the air. In particular, different pipelines do not need to be welded to connect and seal the ports of the two pipelines when they are combined, but the high-temperature welding process will destroy the internal structure of the stainless steel material, making the stainless steel with high corrosion resistance characteristics easy to be corroded. Therefore, the welding place between the gas pipeline joint 16 and the etching gas pipeline 15 on the etching reaction chamber 6 is particularly prone to be corroded by the etching gas, especially when the water vapor in the air enters, it is more prone to corrosion. The water vapor in the air will stay in the first gas line 1, the second gas line 2 and the third gas line 3 shown in Figure 1 and is difficult to volatilize. The water vapor will corrode when it encounters the corrosive gas in the etching gas The weld of the gas line 15 is etched. The existing solution is to replace the first gas pipeline 1, the second gas pipeline 2 and the third gas pipeline 3 in time, or change the material of the etching gas pipeline 15 to a more corrosion-resistant Hastelloy stainless steel to extend the use of the pipeline life. However, the current practice has the problem of greatly increasing the cost, and Hastelloy stainless steel cannot be applied to the situation where CO and other gases are present in the etching gas.

On the basis of the above-mentioned embodiments, the present invention provides an air inlet pipe connection device for connecting the etching gas pipeline 15 and the gas pipe joint 16 on the central air inlet and the peripheral air inlet of the etching reaction chamber 6. As shown in Figure 2, it is a schematic diagram of the structure of the gas inlet pipe connecting device of the present invention when it is used to connect the etching gas pipe 15 and the gas pipe joint 16. This figure also shows a cross-sectional view and an appearance view when the pipe is connected. The air inlet pipe connection device includes a tubular body 17 and a corrosion-resistant seal 18 arranged in the tubular body 17; the etching gas pipeline 15 and the gas pipeline joint 16 respectively extend from the two ends of the tubular body 17 and are connected to each other. The two ends of the tubular body 17 are respectively surrounded and sealed by a corrosion-resistant seal 18; the two ends of the tubular body 17 are respectively fixed to the etching gas line 15 and the gas line joint 16 by welding, that is, the two sides of the tubular body 17 are respectively connected to the gas line joint 16 and the etching The gas pipelines 15 each form a circle of welds 19. Through this design, it is realized that when the etching gas reaction chamber is opened, the etching gas pipeline 15 in contact with the air has no welds, thereby preventing the etching gas pipeline 15 from being corroded and extending the service life of the etching gas pipeline 15. In this embodiment, the etching reaction chamber 6 is composed of an insulating window 7, a side wall of the cavity, a bottom wall of the cavity, etc., and an electrostatic chuck 8 is arranged inside. A wafer 9 can be placed on the electrostatic chuck 8. There are wafer 9 transfer channels 10. The exhaust port (not shown in the figure) is connected to a vacuum device to make the etching reaction chamber 6 into a vacuum environment. The coil 11 above the insulating window 7 is coupled with radio frequency energy through the insulating window 7, and the etching reaction chamber Plasma is formed in the body 6, and the wafer 9 on the electrostatic chuck 8 is etched. The side wall of the etching reaction chamber 6 is provided with a side wall lining 12 so that the side wall of the chamber no longer directly contacts the plasma, avoids the bombardment of the plasma, and facilitates cleaning and replacement. Therefore, after the air inlet pipe connecting device provided by the present invention is used, the metal contamination of the wafer 9 caused by the corrosion of the etching gas pipeline 15 can be further effectively avoided, and the quality of the product is improved.

In this embodiment, in order to limit the position of the corrosion-resistant sealing element, a first annular groove for embedding the corrosion-resistant sealing element 18 may be provided in the tubular body 17. In order to achieve the same purpose, the outer wall of the joint between the etching gas pipeline 15 and the gas pipeline joint 16 can also be combined to form a second annular groove for embedding the corrosion-resistant seal 18.

As shown in Figure 3, in order to limit the position of the tubular body 17, the etching gas pipeline 15 and the gas pipeline joint 16 are respectively provided with a first annular outward extension 151 and a second annular extension on the outer wall away from the docking location. The outward extending portion 161; the first annular outward extending portion 151 and the second annular outward extending portion 161 are combined to form a third annular groove for inserting into the tubular body 17.

In the above embodiment, in order to avoid damage to the internal structure of the stainless steel pipe by heating and reduce the occurrence of corrosion, the outer circumference of the tubular body 17 is respectively aligned with the outer circumference of the first annular outward extending portion 151 and the second annular outward extending portion 161; The weld formed by welding is located at the outer periphery of the joint of the tubular body 17 with the first annular outward extending portion 151 and the second annular outward extending portion 161 respectively, so as to keep the weld away from the etching gas pipeline 15 and the gas pipeline joint The body of 16 prevents the high-temperature welding process from destroying the internal structure of the stainless steel material of the etching gas pipeline 15 and the gas pipeline joint 16, so that the stainless steel with high corrosion resistance becomes easy to be corroded.

Further, in order to reduce the thickness of the tubular body 17 and reduce the material cost of the tubular body 17, a third annular outward extending portion 171 and a fourth annular outward extending portion 172 are respectively provided on both sides of the tubular body 17; The outer extending portion 171 and the fourth annular outward extending portion 172 are respectively aligned with the outer peripheries of the first annular outward extending portion 151 and the second annular outward extending portion 161, so as to satisfy that the welding seam is far away from the etching gas pipeline 15 and the gas On the premise of the body of the pipe joint 16, the unnecessary thickness of the tubular body 17 is reduced as much as possible.

In this embodiment, the tubular body 17 of the air intake pipe connecting device is made of metal, and specifically, various stainless steel materials can be used, especially low-cost SST316L stainless steel pipes. The material of the corrosion-resistant sealing member 18 of the air inlet pipe connection device is Teflon or polyimide, or other materials that can achieve both corrosion resistance and sealing functions. The Teflon used in this embodiment is a polymer compound formed by polymerization of tetrafluoroethylene, which has excellent chemical stability, corrosion resistance, durability, and reliable sealing performance. The gas pipeline joint 16 on the etching reaction chamber 6 is usually a VCR joint. VCR fittings are also called metal gasket face seal fittings, and the English name is Metal Gasket Face Seal Fittings, which are usually used in the connection of pipelines.

In this embodiment, the corrosion-resistant seal 18 that water vapor enters into the etching gas pipeline 15 will not touch the welds welded on both sides of the inlet pipe connection device, thus avoiding the original etching gas. Corrosion of the weld of pipeline 15. In terms of specific structure, the two sides of the outer tubular body 17 are the same as the inner diameters of the gas pipeline joint 16 and the etching gas pipeline 15 respectively, and the internal corrosion-resistant seal 18 can be based on the gas pipeline joint 16 and the etching gas pipeline 15 The specific structure design of the butt joint should only be able to realize the sealing function. For example, an annular groove structure is formed at the joint of the gas pipeline joint 16 and the etching gas pipeline 15, and the corrosion-resistant seal 18 is an annular convex structure arranged inside the tubular body 17 and matched with the annular groove structure. It can be seen from this that the air intake pipe connecting device provided by the present invention can design a corresponding structure according to the specific site structure, so as to achieve the purpose of preventing water vapor from contacting the weld.

Further, the present invention also provides an air intake unit 22 for plasma etching. The air intake unit 22 includes: an etching gas source for providing etching gas; an etching gas pipeline 15 connected to the etching gas source; The gas pipe joint 16 on the etching reaction chamber 6 and the above-mentioned air inlet pipe connection device are used to connect the etching gas pipe 15 and the gas pipe joint 16. In this embodiment, a splitter 4 is provided on the etching gas pipeline 15 for dividing the etching gas pipeline 15 into multiple branches. The etching gas pipeline 15 is also connected to the tuning gas pipeline 5 for mixing tuning gas into the etching gas pipeline 15. In the existing plasma etching process, a simple pipeline modification can be used to add the gas inlet pipe connection device provided by the present invention between the original etching gas pipeline 15 and the gas pipeline joint 16 on the etching reaction chamber 6 Then, the air intake unit 22 of the present invention can be obtained. It can effectively avoid the corrosion of the welding seam of the original etching gas pipeline 15 caused by the entry of water vapor, prolong the service cycle of the etching gas pipeline 15, effectively avoid the metal contamination of the wafer 9 caused by the corrosion of the etching gas pipeline 15, and improve the finished product Yield rate.

In order to effectively control the passage of the etching gas, a valve 13 for opening and closing the etching gas line 15 can be provided on the etching gas line 15, or a flow adjustment device for adjusting the flow of the etching gas, or a valve can be provided at the same time. 13 and flow regulating device. Of course, a pneumatic control valve can be selected to simultaneously realize the opening and closing of the pipeline and the adjustment of the etching gas flow rate, so that the structure of the pipeline is simplified. Furthermore, the valve 13 and the flow regulating device can be incorporated into the existing DCS control system to achieve more convenient operation and monitoring. In order to control the etching gas flow rate, the body of the etching gas pipeline 15 can also be modified. For example, a diameter reducing structure 14 is provided on the etching gas pipeline 15 to limit the etching gas flow rate. The diameter reducing structure 14 may be a reducing tube, a concentric or eccentric orifice, which can be obtained by stamping to achieve a fixed flow restriction.

Figure 4 is a schematic structural diagram of an embodiment of using the above-mentioned air intake unit 22 for plasma processing equipment. The equipment includes an etching gas reaction chamber, the air intake unit 22 provided by the present invention, and the reaction by-products from the etching reaction. The air extraction unit discharged from the cavity 6. The etching gas reaction chamber includes a substantially cylindrical reaction chamber side wall made of metal material. A gas spray device 20 is arranged above the reaction chamber side wall. The gas spray device 20 penetrates the gas mixing device 21 and the gas inlet provided by the present invention. The air unit 22 is connected. In this embodiment, one end of the gas pipeline connector 16 is connected to the gas mixing device 21, and the other end is connected to the etching gas pipeline 15 through the inlet pipeline connection device provided by the present invention.

The etching gas provided by the air inlet unit 22 enters the etching reaction chamber 6 through the gas spray device 20. A base 23 supporting the electrostatic chuck 8 is provided under the etching reaction chamber 6 and the electrostatic chuck 8 is used to place the When processing the wafer 9, the RF power of the RF power source 24 is applied to the susceptor 23, and an electric field is generated in the etching reaction chamber to dissociate the reaction gas into plasma. The plasma contains a large number of electrons, ions, excited atoms, molecules and Active particles such as free radicals, the above-mentioned active particles can have various physical and chemical reactions with the surface of the wafer 9 to be processed, so that the topography of the surface of the wafer 9 is changed, that is, the etching process is completed. An exhaust pump 25 is also provided under the etching reaction chamber 6 as a pumping unit for exhausting reaction byproducts into the vacuum reaction chamber. Using the ion treatment equipment provided by the present invention can effectively avoid the problem of corrosion of the welding seam of the etching gas pipeline 15 caused by the opening of the etching gas reaction chamber, and it is compatible with various etching gases.

In summary, in the existing plasma etching process, after the air inlet pipe connection device provided by the present invention and the air inlet unit for plasma etching containing it are used, what the water vapor enters into the etching gas pipeline is Corrosion-resistant seals will not touch the welds welded on the outer sides of the inlet pipe connection device, thus avoiding the corrosion of the welds of the original etching gas pipeline, extending the service life of the etching gas pipeline, and further effectively avoiding The metal contamination of the wafer caused by the corrosion of the etching gas pipeline improves the quality of the product.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as limiting the present invention. Various modifications and substitutions to the present invention will be obvious after reading the above content by those with ordinary knowledge in the field. Therefore, the scope of protection of the present invention should be limited by the scope of the attached patent application.

1: The first gas pipeline 2: The second gas pipeline 3: The third gas pipeline 4: shunt 5: Tuning gas pipeline 6: Etching the reaction chamber 7: Insulation window 8: Electrostatic chuck 9: chip 10: Transfer channel 11: coil 12: Side wall lining 13: Valve 14: Variable diameter structure 15: Etching gas pipeline 151: First annular outward extension 16: Gas pipeline joint 161: Second annular outward extension 17: Tubular body 171: Third ring outward extension 172: Fourth annular outward extension 18: Corrosion-resistant seal 19, 29: Weld 20: Gas spray device 21: Gas mixing device 22: intake unit 23: Pedestal 24: RF power source 25: Exhaust pump

Figure 1 is a schematic diagram of the structure of the existing etching reaction chamber and its air inlet unit; Figure 2 is a schematic structural diagram of an embodiment of the air intake pipe connecting device of the present invention; Figure 3 is a schematic structural view of another embodiment of the air intake pipe connecting device of the present invention; Figure 4 is a schematic structural diagram of the air intake unit provided by the present invention used in plasma processing equipment.

15: Etching gas pipeline

16: Gas pipeline joint

17: Tubular body

18: Corrosion-resistant seal

19: Weld

Claims (10)

An air inlet pipe connecting device is used to connect an etching gas pipeline and a gas pipe joint on an etching reaction chamber, wherein the air inlet pipe connecting device includes a tubular body and a pipe arranged in the tubular body. Corrosion-resistant seal; the etching gas pipeline and the gas pipeline joint respectively extend from the two ends of the tubular body and are connected, and the joint is surrounded and sealed by the corrosion-resistant seal; the two ends of the tubular body are respectively The joint with the etching gas pipeline and the gas pipeline is fixed by welding. According to the air inlet pipe connection device described in the first item of the scope of patent application, a first annular groove for embedding the corrosion-resistant seal is provided in the tubular body. As described in the first item of the scope of patent application, the outer wall of the joint of the etching gas pipeline and the gas pipeline joint is combined to form a second annular groove for embedding the corrosion-resistant seal. As described in the first item of the scope of patent application, the air inlet pipeline connection device, wherein the etching gas pipeline and the gas pipeline joint are respectively provided with a first annular outward extending portion and a second outer wall on the outer wall away from the joint. Annular outward extending portion; the first annular outward extending portion and the second annular outward extending portion are combined to form a third annular groove for embedding in the tubular body. According to the air intake pipe connecting device described in claim 4, the outer periphery of the tubular body is respectively aligned with the outer periphery of the first annular outward extending portion and the second annular outward extending portion; formed by welding A weld is located at the outer periphery of the joint of the tubular body with the first annular outward extending portion and the second annular outward extending portion, so that the weld is away from the etching gas pipeline and the gas pipeline joint The body. According to the air inlet pipe connection device described in the fifth item of the scope of patent application, a third annular outward extending portion and a fourth annular outward extending portion are respectively provided on both sides of the tubular body; the third annular outward extending portion The extending portion and the fourth annular outward extending portion are respectively aligned with the outer peripheries of the first annular outward extending portion and the second annular outward extending portion. In the air inlet pipe connecting device described in the first item of the scope of patent application, the material of the tubular body is stainless steel. As described in the first item of the scope of patent application, the air inlet pipe connection device, wherein the material of the corrosion-resistant seal is Teflon or polyimide. In the air inlet pipe connection device described in item 1 of the scope of patent application, the gas pipe joint is a VCR joint. An air intake unit for plasma etching, wherein the air intake unit includes: an etching gas source for supplying etching gas; an etching gas pipeline connected to the etching gas source; A gas pipeline joint and the gas inlet pipeline connection device according to any one of items 1 to 9 in the scope of patent application are used to connect the etching gas pipeline and the gas pipeline joint.

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