TWI770445B - Air intake pipeline connection device and air intake unit for plasma etching containing the same - Google Patents

Abstract

The invention discloses an air intake pipeline connection device and an air intake unit for plasma etching containing the same. The air intake pipeline connection device comprises a tubular body and a corrosion-resistant seal arranged in the tubular body; an etching gas pipeline The joints and gas pipelines are respectively extended from both ends of the tubular body and are butted, and the joints are surrounded and sealed by corrosion-resistant seals; the two ends of the tubular body are respectively fixed with the etching gas pipeline and the gas pipeline joints by welding. After adopting the present invention, the water vapor entering the etching gas pipeline will contact with the corrosion-resistant seal, and will not contact the welding seam welded on both sides of the connection device of the intake pipeline, thus avoiding the original welding seam of the etching gas pipeline. The corrosion of the etching gas pipeline prolongs the service life of the etching gas pipeline, effectively avoids the metal pollution of the wafer caused by the corrosion of the etching gas pipeline, and improves the quality of the product.

Description

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

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

In the existing plasma etching technology, Cl2, COS, HBr, SiCl4 and other corrosive gases are often introduced into the inductively coupled plasma (ICP, Inductive Coupled Plasma) and capacitively coupled (CCP) type etching machines. ) to etch.

These corrosive gases need to enter the reaction chamber through gas line metal pipes. At present, most gas pipelines are made of 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 opening, the water vapor will stay in the gas pipeline and it is difficult to volatilize. When water vapor encounters corrosive gases, it will corrode the weld. Studies have shown that when the water vapor concentration exceeds 0.5PPM, the welds of metal pipes will be corroded; when the water vapor concentration is greater than 100PPM, corrosion spots are visible to the naked eye. The corrosion of the weld will bring out heavy metals such as Cr and Mn in the components of the stainless steel and deposit on the wafer, causing metal pollution to the wafer. The current common practice is that the gas pipeline needs to be replaced every time the cavity is opened, which is costly and time-consuming to maintain. Therefore, there is currently no solution that can effectively prevent water vapor from corroding gas pipeline welds.

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

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

In the above-mentioned air inlet pipeline connection device, a first annular groove for embedding a corrosion-resistant seal is provided in the tubular body.

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

The above-mentioned 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 annular outward extending portion on the outer wall away from the butt joint; A third annular groove for inserting into the tubular body is formed between the outwardly extending portion and the second annular outwardly extending portion.

The above-mentioned air inlet pipeline connection device, wherein the outer circumference of the tubular body is respectively aligned with the outer circumference of the first annular outwardly extending portion and the second annular outwardly extending portion; The outer periphery of the junction of the annular outward extension and the second annular outward extension is positioned to keep the weld away from the etching gas line and the body of the gas line joint.

The above-mentioned air inlet pipeline connection device, wherein, both sides of the tubular body are respectively provided with a third annular outward extension portion and a fourth annular outward extension portion; the third annular outward extension portion and the fourth annular outward extension portion Align with the outer peripheries of the first annular outward extension and the second annular outward extension, respectively.

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

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

In the above-mentioned air inlet pipeline connection device, the gas pipeline 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; disposed in the etching reaction chamber The gas pipeline joint on the upper part and the above-mentioned 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 prior art plasma etching process, after using the air inlet pipeline connection device provided by the present invention and the air intake unit for plasma etching provided by the present invention, the water vapor What is in contact with the etching gas pipeline is the corrosion-resistant seal, which will not contact the welds welded on the outer sides of the intake pipeline connection device, thus avoiding the corrosion of the original etching gas pipeline welds and prolonging the etching process. The service life of the gas pipeline can further effectively avoid the metal pollution of the wafer caused by the corrosion of the etching gas pipeline, and improve the quality of the product.

1: The first gas line

2: Second gas line

3: The third gas line

4: Shunt

5: Tuning gas lines

6: Etch the reaction chamber

7: Insulation window

8: Electrostatic chuck

9: Wafer

10: Transfer channel

11: Coil

12: sidewall lining

13: Valve

14: Variable diameter structure

15: Etch gas lines

151: The first annular outward extension

16: Gas line connector

161: Second annular outward extension

17: Tubular body

171: Third annular outward extension

172: Fourth annular outward extension

18: Corrosion Resistant Seals

19, 29: Welds

20: Gas spray device

21: Gas mixing device

22: Air intake unit

23: Pedestal

24: RF Power Source

25: Exhaust pump

Figure 1 is a schematic structural diagram of an existing etching reaction chamber and its air intake unit; Figure 2 is a schematic structural diagram of an embodiment of the air inlet pipeline connection device of the present invention; Figure 3 is the air intake pipeline connection device of the present invention. A schematic structural diagram of another embodiment; FIG. 4 is a structural schematic diagram of the air intake unit provided by the present invention used in a plasma processing apparatus.

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

As shown in FIG. 1 , it is a schematic structural diagram of a conventional embodiment of the etching reaction chamber 6 and its gas inlet unit 22 . A part of the etching gas in the gas main line is divided by the flow divider 4 and then transported through the first gas pipeline 1 and the second gas pipeline 2, and then enters the etching reaction chamber 6 through the central gas inlet of the etching reaction chamber 6. The other part of the etching gas is directly transported through the third gas pipeline 3 , and then enters the interior of the etching reaction chamber 6 through the peripheral air inlet of the etching reaction chamber 6 . The first gas line 1 , the second gas line 2 and the third gas line 3 together constitute the etching gas line 15 . The tuning gas line 5 for delivering the tuning gas is connected with the first gas line 1, the second gas line 2 and the third gas line 3 at the same time, so that the tuning gas is mixed into the etching gas, and then transported to the etching reaction chamber 6 . At present, most of the etching gas pipelines 15 are easy to use and easy to obtain, and the low-cost SST316L stainless steel is not easily corroded. However, this design also brings the following problems: when the etching reaction chamber 6 is opened every time, it is The etching gas line 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 and sealed at the ports of the two pipelines, but the high-temperature welding process will destroy the internal structure of the stainless steel material, making the original stainless steel with high anti-corrosion properties easy to be corroded. Therefore, the weld of the gas pipeline joint 16 on the etching reaction chamber 6 and the etching gas pipeline 15 is particularly prone to be corroded by the etching gas, especially when the water vapor in the air enters, the corrosion is more likely to occur. 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, and the water vapor will corrode when it encounters the corrosive gas in the etching gas. Etch the weld of the gas line 15. 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 to replace the material of the etching gas pipeline 15. Change to more corrosion-resistant Hastelloy stainless steel for longer line life. However, the current practice has the problem of greatly increasing the cost, and the Hastelloy stainless steel is not suitable for the presence of CO and other gases in the etching gas.

On the basis of the above embodiments, the present invention provides a gas inlet pipeline connection device for connecting the etching gas pipeline 15 and the gas pipeline joints 16 on the central gas inlet and the peripheral gas inlet of the etching reaction chamber 6 . As shown in FIG. 2 , it is a schematic structural diagram of the inlet pipeline connection device of the present invention used to connect the etching gas pipeline 15 and the gas pipeline joint 16 . The air inlet pipeline 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 both ends of the tubular body 17 and are butted, and the butt The two ends of the tubular body 17 are respectively fixed with the etching gas pipeline 15 and the gas pipeline joint 16 by welding, that is, the two sides of the tubular body 17 are respectively connected with the gas pipeline joint 16 and the etching gas pipeline joint 16. The gas lines 15 each form a circle of welds 19 . Through this design, when the etching gas reaction chamber is opened, the etching gas pipeline 15 in contact with the air has no welding seam, thereby preventing the etching gas pipeline 15 from being corroded and prolonging 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 chamber, a bottom wall of the chamber, etc., and an electrostatic chuck 8 is provided inside, on which a wafer 9 can be placed, and a side wall of the chamber is provided There are wafer 9 transfer channels 10 . The exhaust port (not shown in the figure) is connected with a vacuum device, and the etching reaction chamber 6 is made into a vacuum environment. The coil 11 above the insulating window 7 is connected with radio frequency energy, and is coupled through the insulating window 7. In the etching reaction chamber A plasma is formed in the body 6 to etch the wafer 9 on the electrostatic chuck 8 . The sidewall of the etching reaction chamber 6 is provided with a sidewall lining 12 , so that the sidewall of the chamber is no longer in direct contact with the plasma, free from the bombardment of the plasma, and more convenient for cleaning and replacement. Therefore, after using the air inlet pipeline connection device provided by the present invention, the metal pollution 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 can be improved.

In this embodiment, in order to limit the position of the corrosion-resistant seal, a first annular groove for embedding the corrosion-resistant seal 18 may be provided in the tubular body 17 . For the same purpose, also A second annular groove can be formed on the outer wall where the etching gas line 15 meets the gas line joint 16 to embed the corrosion-resistant seal 18 .

As shown in FIG. 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 extending portion 151 and a second annular outward extension on the outer walls away from the butt joint. The outwardly extending portion 161 ; a third annular groove is formed between the first annular outwardly extending portion 151 and the second annular outwardly extending portion 161 for embedding the tubular body 17 .

In the above embodiment, in order to prevent the stainless steel pipe from being heated to damage the internal structure 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 outwardly extending portion 151 and the second annular outwardly extending portion 161; The weld formed by welding is located at the outer periphery of the tubular body 17 where the first annular outwardly extending portion 151 and the second annular outwardly extending portion 161 are combined, respectively, so as to keep the welding seam away from the etching gas pipeline 15 and the gas pipeline joint. 16 body, so as to prevent 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 original stainless steel with high anti-corrosion properties becomes easy to be corroded.

Further, in order to reduce the thickness of the tubular body 17 to reduce the material cost of the tubular body 17, both sides of the tubular body 17 are respectively provided with a third annular outward extending portion 171 and a fourth annular outward extending portion 172; The outer extension portion 171 and the fourth annular outward extension portion 172 are aligned with the outer peripheries of the first annular outward extension portion 151 and the second annular outward extension portion 161, respectively, so that the welding seam can be kept away from the etching gas line 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 pipeline connection device is made of metal material, specifically, various stainless steel materials, especially low-cost SST316L stainless steel pipe materials can be used. The material of the corrosion-resistant sealing member 18 of the connection device of the intake pipe is Teflon or polyimide, or other materials that can achieve both corrosion-resistant 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 sealing performance. reliable. The gas pipeline joint 16 on the etching reaction chamber 6 is commonly a VCR joint. VCR joints, also known as metal gasket face seal joints, English name: Metal Gasket Face Seal Fittings, usually used in the connection of pipelines.

In this embodiment, the corrosion-resistant seal 18 is contacted by the water vapor entering the etching gas pipeline 15, and will not contact the welding seams welded on both sides of the outside of the connection device of the intake pipeline, thus avoiding the original etching gas Corrosion of pipeline 15 welds. As far as the specific structure is concerned, the two sides of the outer tubular body 17 are respectively the same as the inner diameters of the gas pipeline joint 16 and the etching gas pipeline 15, and the internal corrosion-resistant seal 18 can be adjusted according to the gas pipeline joint 16 and the etching gas pipeline 15. The specific structural design of the butt joint can be as long as the sealing function can be achieved. For example, an annular groove structure is formed at the butt joint of the gas pipeline joint 16 and the etching gas pipeline 15, and the corrosion-resistant sealing member 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 inlet pipeline connection device provided by the present invention can design a corresponding structure according to the specific on-site structural conditions, so as to achieve the purpose that the water vapor cannot contact the welding seam.

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 pipeline joint 16 on the etching reaction chamber 6 and the above-mentioned inlet pipeline connection device are used to connect the etching gas pipeline 15 and the gas pipeline joint 16 . In this embodiment, a flow divider 4 is provided on the etching gas pipeline 15 for dividing the etching gas pipeline 15 into a plurality of branches. The etching gas line 15 is also connected to the tuning gas line 5 for mixing the tuning gas into the etching gas line 15 . In the existing plasma etching process, the inlet pipeline connection device provided by the present invention can be added between the original etching gas pipeline 15 and the gas pipeline joint 16 on the etching reaction chamber 6 through simple pipeline modification. The air intake unit 22 of the present invention can be obtained. It can effectively avoid the corrosion of the original etching gas pipeline 15 welding seam due to the entry of water vapor, prolong the service life of the etching gas pipeline 15, effectively avoid the metal pollution of the wafer 9 caused by the corrosion of the etching gas pipeline 15, and improve the quality of the finished product. Yield.

In order to effectively control the introduction of the etching gas, a valve 13 for opening and closing the etching gas line 15 may be provided on the etching gas line 15, or a flow regulating device for adjusting the flow rate of the etching gas may be provided, or a valve may be set at the same time. 13 and flow regulating device. Of course, a pneumatic regulating valve can be selected to realize the opening and closing of the pipeline and the adjustment of the flow rate of the etching gas at the same time, so as to simplify the structure of the pipeline. Further, 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 flow rate of the etching gas, the body of the etching gas pipeline 15 can also be modified, for example, a variable diameter structure 14 is arranged on the etching gas pipeline 15 to limit the flow rate of the etching gas. The reducing structure 14 can be a reducing pipe, can be a concentric head or an eccentric head, and can be obtained by stamping to achieve a fixed flow restriction.

FIG. 4 is a schematic structural diagram of an embodiment in which the above-mentioned gas inlet unit 22 is used in a plasma processing apparatus. The apparatus includes an etching gas reaction chamber, the gas inlet unit 22 provided by the present invention, and a gas inlet unit 22 for removing 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 unit 22 is connected. In this embodiment, one end of the gas pipeline joint 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 connecting device provided by the present invention.

The etching gas provided by the air intake unit 22 enters the etching reaction chamber 6 through the gas spraying device 20, and a base 23 supporting the electrostatic chuck 8 is arranged below the etching reaction chamber 6, and the electrostatic chuck 8 is used for placing the waiting The wafer 9 is processed, the radio frequency power of the radio frequency power source 24 is applied to the base 23, and an electric field is generated in the etching reaction chamber to dissociate the reaction gas into plasma, and 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 undergo 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 arranged below the etching reaction chamber 6 as an air extraction unit for discharging the reaction by-products into the vacuum reaction chamber. Using the plasma treatment equipment provided by the present invention can effectively avoid the etching gas The problem of corrosion of the welding seam of the etching gas pipeline 15 caused by the opening of the reaction chamber is compatible with various etching gases.

To sum up, in the existing plasma etching process, after using the air inlet pipeline connection device provided by the present invention and the air inlet unit for plasma etching containing the same, the water vapor enters the etching gas pipeline and contacts the Corrosion-resistant seals will not contact the welds welded on both sides of the inlet pipe connection device, thus avoiding the corrosion of the original etching gas pipeline welds, extending the service life of the etching gas pipeline, and can further effectively avoid The quality of the product is improved due to metal contamination of the wafer caused by corrosion of the etching gas lines.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be construed as limiting the present invention. Various modifications and alternatives to the present invention will be apparent to those of ordinary skill in the art upon reading the foregoing disclosure. Therefore, the protection scope of the present invention should be defined by the appended claims.

15: Etch gas lines

16: Gas line connector

17: Tubular body

18: Corrosion Resistant Seals

19: Welds

Claims (9)

An air inlet pipeline connection device for connecting an etching gas pipeline and a gas pipeline joint on an etching reaction chamber, wherein the air inlet pipeline connection device comprises a tubular body and a Corrosion-resistant seals; the etched gas pipeline and the gas pipeline joints respectively extend into and butt joints from both ends of the tubular body, and the butt joints are surrounded and sealed by the corrosion-resistant seals; the two ends of the tubular body are respectively It is fixed with the etching gas pipeline and the gas pipeline joint by welding; wherein the tubular body is provided with a first annular groove for embedding the corrosion-resistant seal. The inlet piping connection device as claimed in claim 1, wherein the outer wall of the butt joint of the etching gas piping and the gas piping joint is combined to form a second annular groove for embedding the corrosion-resistant sealing member. The air inlet pipeline connection device as claimed in claim 1, wherein the etching gas pipeline and the gas pipeline joint are respectively provided with a first annular outward extending portion and a second annular outward extension on the outer wall away from the butt joint. an 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 into the tubular body. The air intake pipeline connection device as claimed in claim 3, wherein the outer circumference of the tubular body is aligned with the outer circumferences of the first annular outwardly extending portion and the second annular outwardly extending portion, respectively; formed by welding A welding seam is located at the outer peripheral position of the tubular body and the first annular outward extension portion and the second annular outward extending portion respectively, so that the welding seam is away from the etching gas pipeline and the gas pipeline joint. 's body. The air intake pipeline connection device as claimed in claim 4, wherein two sides of the tubular body are respectively provided with a third annular outward extending portion and a fourth annular outward extending portion; the third annular outward extending portion is The extension and the fourth annular outward extension are aligned with the outer peripheries of the first annular outward extension and the second annular outward extension, respectively. The intake pipe connection device according to claim 1, wherein the material of the tubular body is stainless steel. The air intake pipeline connection device according to the claim 1, wherein the material of the corrosion-resistant seal is Teflon or polyimide. The air intake pipeline connection device according to claim 1, wherein the gas pipeline joint is a VCR joint. A gas inlet unit for plasma etching, wherein the gas inlet unit comprises: an etching gas source for providing etching gas; an etching gas pipeline connected with the etching gas source; an etching gas pipeline arranged on an etching reaction chamber A gas pipeline joint and the inlet pipeline connection device according to any one of the first to eighth items of the patent application scope are used for connecting the etching gas pipeline and the gas pipeline joint.

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