TWM621547U - A semiconductor waste gas treatment system - Google Patents

Abstract

A semiconductor waste gas treatment system is composed of a vacuum pumping device, a plasma processing device and a wet scrubbing device. A two stages vacuum pumping is employed, such as a booster pump along with a dry pump. A low pressure plasma process is adopted and installed between the two pumps, leading to efficient gas reactions with a low energy consumption. Meanwhile, the back stream issues possibly caused by the plasma process is eliminated in this invention. Above all, a large flow of purge gas such as nitrogen usually used in a dry pump is not necessary, resulting in the reduction of the cost of pumping system and the amount of emission of NOx that is harmful to environment. In the last stage, a jet flow micro-bubble wet scrubber is used for the efficient absorption of gases and particles absorption; Moreover, it can generate a rough vacuum at the output port of the pump, which significantly increases the pumping efficiency and eliminates the particle blockage inside the pump.

Description

A semiconductor waste gas treatment system

This creation is about an exhaust gas treatment system, especially about a semiconductor exhaust gas treatment system.

The production process of semiconductors uses a lot of flammable, corrosive or highly toxic reactive gases, but the utilization rate of reactive gases in many semiconductor processes is very low, so the residual gases and reaction products that are not fully reacted in the process must be Evacuate the reaction process chamber. These mixed gases are generally referred to as process waste gas or tail gas and must be converted into harmless or treatable substances before they can be discharged.

The current exhaust system is mainly composed of a turbo pump connected to the reaction process chamber, a mechanical pump and a local scrubber system. The process exhaust gas is sequentially drawn out of the reaction process chamber through the turbo vacuum pump, exhaust pipe and mechanical pump, and then sent to the local exhaust gas treatment system for treatment and then sent to the central scrubber system for discharge.

In order to properly treat process waste gas, many technologies have been proposed and used. For example, there is currently a prior art that uses an extraction pump to discharge the process waste gas to a combustion scrubber for waste gas treatment before discharging the process waste gas, such as Taiwan's Invention Patent No. I487872. However, the combustion scrubber is not effective for the treatment of fluorine-containing compounds, and it has to keep running and provide a large amount of fuel gas at any time, so the cost is greatly increased and energy is consumed, and the fuel gas is flammable and explosive gas, which will increase the danger to public security. In addition, although there is another prior art that uses a catalyst thermal cracking method, the catalyst has problems of aging and poisoning, and the cost of catalyst replacement and recycling is quite high. In addition, catalytic thermal cracking also has to keep running at all times and likewise consumes a lot of energy.

In addition, although there are currently technologies that use plasma torch scrubbers for waste gas treatment, such as Taiwan's invention patent No. I285066, although plasma has been proven to effectively decompose process waste gas, especially for perfluorocarbons ( (Perfluorinated Compounds, PFCs). However, they operate under atmospheric pressure and consume a lot of energy. At the same time, because the plasma temperature exceeds thousands of degrees, the system components are not only expensive but also have a short service life. In particular, the stability of atmospheric plasma is not good. , it is easy to cause the problem of plasma extinguishing due to changes in operating conditions.

On the other hand, the existing theoretical technology proposes to install a plasma treatment device before the mechanical pump to perform waste gas treatment under low pressure. The results show that the high electron energy at low pressure can effectively dissociate the exhaust gas. Although the treatment effect is good, because the plasma treatment device is directly connected to the back end of the turbo vacuum pump, there will be doubts about the backflow of the gas reactant to pollute the process. Unacceptable to semiconductor processes and not currently in use.

The current mechanical pump adopts a two-stage combination, that is, the first stage is a booster pump, and the second stage is a dry pump. The booster pump can accelerate the system to reach a lower air pressure due to the large pumping rate, so as to facilitate the second stage dry pump to achieve the set air pressure for operation. Existing mechanical pump operations must introduce a large amount of purge gas, such as nitrogen, into the second stage (later stage) dry pump to dilute flammable, corrosive or highly toxic process waste gas, and at the same time to slow down the production process during the process. The problem of pipe blockage caused by solid particles. Since the gas flow is quite large, a high-power pump must be used, which increases the operating cost and consumes energy. Moreover, a large amount of nitrogen subsequently enters into the current local exhaust gas treatment system such as a combustion type or thermal reaction type scrubber, which will generate a large amount of nitrogen oxides (NOx) and other greenhouse gases, causing secondary pollution to the environment.

Furthermore, even if a large amount of purge gas is introduced, solid particles may still block the dry pump in the second (later) stage, especially its outlet, in some processes. This would seriously reduce the gas pumping efficiency, while improving operating current dry pump, not only increases energy consumption increased operating costs, and even cause pump damage caused by dry process downtime.

In order to solve the problems of the above-mentioned conventional technologies, the purpose of this creation is to provide a system that can effectively treat exhaust gas, and can reduce the energy consumption of mechanical pumps and greatly reduce the generation of greenhouse gases such as nitrogen oxides (NOx), and at the same time can effectively Solve the problem of blockage of solid particles to improve the service life of dry pump. On the other hand, this creation uses low-pressure plasma waste gas treatment. At the same time, compared with the atmospheric-pressure plasma torch, the low-pressure plasma is easy to excite, and the operation is stable and the energy consumption is low, the component damage rate is low, and the maintenance cycle is long. More importantly, there is no problem of generating gas and particle backflow contaminating the semiconductor process chamber, so it can be accepted by current semiconductor process systems.

Different from the previous technology, the semiconductor waste gas treatment system of the present invention includes a two-stage vacuum device, a plasma treatment chamber, a reaction gas supply chamber and a jet-type microbubble wet scrubbing device. At the same time, it also includes integrated control signals to ensure that the plasma is activated and the mixed reaction gas is input when there is process waste gas to be treated, so as to save energy and improve the service life of the plasma system.

In order to achieve the aforementioned purpose, the present invention proposes a semiconductor waste gas treatment system, which is suitable for treating at least one process waste gas generated by a process waste gas source. Composition of the processing device. Wherein, the vacuum pumping device is a two-stage pump structure, which includes a first pump and a second pump. The first pump generates a first low pressure environment to extract the process exhaust gas generated by the process exhaust gas source, the second pump generates a second low pressure environment between the first pump and the second pump, and the plasma treatment device is arranged in the first pump. 2. Perform a low-pressure plasma treatment on the process waste gas in a low-pressure environment, and at the same time add a suitable mixed reaction gas to convert the process waste gas into a harmless, stable or water-soluble reaction product gas, such as the treatment of CH ₄ and CHF ₃ . The mixed gas is introduced into the water gas, and the treatment efficiency (Destruction Removal Efficiency, DRE) can exceed 90%. _{When NF 3 is} treated by mixing water and gas, the water gas is dissociated by electrons in the plasma into active particles of O, H and OH, which can react _{with the particles NF x from which NF 3} is dissociated by the plasma. For example: OH + NF ₂ → NOF + HF, H + NF → N + HF, H + F → HF. HF, on the other hand, can be effectively treated by wet scrubbing.

At the same time, low-pressure plasma treatment can also be used to miniaturize or remove solid particles carried by the process exhaust gas. For example, when NF ₃ is used to clean the process cavity _{, mixed gases such as SiF 4} , F, and NF _x will be generated, and the residues of the previous process will be generated. Particles of SiO ₂ are also mixed into the exhaust gas together, and these particles tend to aggregate together and transform into larger particles, which are deposited in the dry pump to form blockages. If the plasma is excited before entering the dry pump so that SiO _{2 reacts with NF x} and F remaining in the exhaust gas, _{the size of SiO 2} can be reduced so that it is not easy to accumulate in the pump as the gas is discharged.

Among them, the exhaust gas scrubbing treatment device is a jet-type micro-bubble wet exhaust gas scrubbing device, which generates a third low-pressure environment at the gas outlet end of the second pump by the principle of a Venturi tube, and is improved by the third low-pressure environment. The pumping efficiency of the second pump in turn can greatly reduce the accumulation of solid particles by the second pump. Finally, the mixed gas of the reaction gas and the particles is sucked by the wet scrubbing device to form microbubbles in the cleaning liquid, so that the cleaning liquid can fully dissolve the reaction gas and capture the particles carried by the reaction gas.

Among them, the vacuum pumping device is a two-stage vacuum device, and the first pump is arranged between the process exhaust gas source and the plasma treatment device, so as to use the first pump to isolate the reaction formation obtained after the low-voltage plasma treatment. Gases and particulates are prevented from flowing back and contaminating the process exhaust source.

Among them, the process exhaust gas will be pre-converted by the plasma treatment device into a gas that is stable and safe or can be effectively treated by the subsequent wet scrubbing device before being sucked into the second pump. In the old technology, the second pump ( Dry pump) must input a large flow of purge gas (such as nitrogen) to dilute the flammable, corrosive or highly toxic process waste gas measures can greatly reduce the operation.

Wherein, the plasma processing device switches between the standby state and the operating state according to a control signal. When the process exhaust gas source starts to discharge the process exhaust gas, the plasma processing device switches from the standby state to the operating state so as to operate in the first low pressure environment. In the next step, low-voltage plasma treatment is performed on the process exhaust gas. When the process exhaust gas source stops discharging the process exhaust gas, the plasma treatment device is switched from the operating state to the standby state.

Wherein, when the plasma treatment device performs low-pressure plasma treatment on the process waste gas, it first mixes the process waste gas with a reaction gas according to the above-mentioned control signal.

The plasma processing device is a plasma processing chamber, and a mixer is used as a reaction gas supply chamber for introducing the reaction gas, so that the reaction gas is mixed with the process exhaust gas.

Among them, the process exhaust gas is perfluorocarbons (PFCs), nitrogen oxides (NO _x ), sulfur hexafluoride (SF ₆ ), nitrogen trifluoride (NF ₃ ), ammonia (NH ₃ ), boron ethane ( B ₂ H ₆ ), hydrofluorocarbons (HFCs), hydrocarbons (C _x H _y ) and/or CCl ₄ and the like.

Wherein, if the semiconductor process is an atomic layer deposition (ALD) process, the process waste gas is trimethylaluminum (TMA), tetrakis(ethylmethylamino)zirconium (TEMAZ) and/or tetrakis(ethylmethyl) amino) hafnium (TEMAH).

The reactive gas may be oxygen (O ₂ ), helium (He), argon (Ar), nitrogen (N ₂ ), hydrogen (H ₂ ) and/or water (H ₂ O).

The first pump of the vacuum pumping device is a booster pump, and the second pump of the vacuum pumping device is a dry pump.

Wherein, the air pressure of the first low pressure environment generated by the first pump of the vacuum pumping device is 100 torr to 10 ^-3 torr.

Wherein, the air pressure of the second low pressure environment generated by the second pump of the vacuum pumping device is 100 torr to 10 ^-3 torr.

Among them, the exhaust gas scrubbing treatment device is a jet-type microbubble wet exhaust gas scrubbing device, and the air pressure of the third low-pressure environment generated by it is 400 torr to 600 torr.

Among them, the exhaust gas washing and treatment device is a jet type micro-bubble wet exhaust gas washing device, which includes: a treatment tank includes an inner tank and an outer tank for containing washing liquid; and a jet pipe, wherein the washing liquid is injected into the treatment tank through the jet pipe. In the inner tank, the gas generated by the above reaction is cut to form micro-bubbles to be dissolved in the washing liquid, and then the water vapor of the washing liquid raised by the micro-bubbles overflows into the outer tank.

Wherein, the plasma processing device is a radio frequency plasma generation source, a microwave plasma generation source or a high voltage discharge source.

The plasma processing device is a microwave plasma generating source with a coaxial microwave resonant cavity.

The microwave plasma generating source includes a microwave source, a coaxially arranged metal coupling antenna, a ceramic tube and a hollow cylinder, wherein the ceramic tube is located in the center of the cylinder and the metal coupling antenna is located in the center of the ceramic tube, and the microwave source is located on the ceramic tube and Located on one side of the metal-coupled antenna.

Among them, the power of the microwave plasma generation source is between 1,000W and 5,000W.

The source of process exhaust gas is a semiconductor process chamber or a turbo vacuum pump connected to the semiconductor process chamber to discharge process exhaust gas.

Based on the above, the semiconductor waste gas treatment system of this creation adopts a low pressure plasma treatment device, which has the following advantages:

(1) The vacuum pumping device can generate a first low pressure environment to extract the process exhaust gas generated by the process exhaust gas source. The vacuum pumping device can form a second low pressure environment between the first pump and the second pump, and the plasma treatment The device can simultaneously use the second low pressure environment to perform low pressure plasma treatment on the process exhaust gas. In addition, the plasma processing device can be switched from the standby state to the running state only when the process exhaust gas begins to be discharged, so as to save energy.

(2) The exhaust gas scrubbing treatment device is a jet micro-bubble wet exhaust gas scrubbing device. When the scrubbing liquid is sprayed at a high speed, the reaction gas obtained after the low-pressure plasma treatment can be converted into micro-bubbles, which greatly increases the contact area and contact time. , which helps to dissolve the gas generated by the above reaction and capture the particles, and can simultaneously generate a rough vacuum state between about 400torr to 600torr at the air inlet, so as to effectively extract the vacuum from the connected vacuum device. Inhaling the above-mentioned reaction gas and particles for washing can also avoid clogging of the vacuum pumping device, improve the operating efficiency of the vacuum pumping device and reduce the required power.

(3) By setting up a plasma treatment device to treat the process exhaust gas before the harmful process exhaust gas enters the second pump (dry pump), it can greatly reduce the introduction of nitrogen to dilute the toxic gas or even do not need to introduce nitrogen, so it can reduce nitrogen The generation of oxides and carbon monoxide avoids secondary pollution and can reduce the required operating specifications such as pumping power and pumping flow.

(4) By introducing the corresponding reactive gases, such as oxygen and water, stable precursors, such as oxides, can be formed, which can effectively make the more difficult process waste gas form the more easily handled reaction gas, and miniaturize the particles , and even eliminate particulates, thereby reducing toxic and greenhouse gases.

(5) The plasma treatment device is installed after the first pump of the vacuum pumping device, which can effectively prevent the reaction gas and particles obtained after the low-pressure plasma treatment from flowing back into the process waste gas source, and the second pump and the The exhaust gas scrubbing treatment device can also provide negative pressure suction, which is more conducive to the return of the above-mentioned reaction gas and particles to the process exhaust gas source and can prevent clogging.

(6) The plasma treatment device can effectively decompose the chemical bonds of the precursors of the atomic layer deposition (ALD) process, and can make the above-mentioned reaction gas into the gas phase to reduce the possibility of generating particles, so it can effectively prolong the maintenance period.

(7) The plasma processing device can use the structure of a coaxial microwave resonant cavity. The power used is, for example, between 1,000W and 5,000W, depending on the type of waste gas and the flow rate.

In order to enable Jun Shen to have a further understanding and understanding of the technical features of this creation and the technical effects that can be achieved, I would like to provide a preferred embodiment and a detailed description as follows.

In order to facilitate the understanding of the technical features, content and advantages of this creation and the effects that can be achieved, this creation is hereby matched with the drawings and described in detail as follows in the form of embodiment, and the drawings used therein are only for the purpose of For the purpose of illustration and auxiliary instructions, it may not necessarily be the real scale and precise configuration after the implementation of this creation. Therefore, the proportion and configuration relationship of the attached drawings should not be interpreted or limited to the scope of rights of this creation in actual implementation. In addition, to facilitate understanding, the same elements in the following embodiments are denoted by the same symbols.

In addition, the terms used in the whole specification and the scope of the patent application, unless otherwise specified, usually have the ordinary meaning of each term used in this field, in the content disclosed herein and in the special content. Certain terms used to describe the present creations are discussed below or elsewhere in this specification to provide those skilled in the art with additional guidance in the description of the present creations.

Regarding the use of "first", "second", "third", etc. in this document, it does not specifically refer to the order or order, nor is it used to limit the creation, it is only to distinguish components described in the same technical terms or operation only.

Secondly, if the words "comprising", "including", "having", "containing" and the like are used herein, they are all open-ended words, that is, they mean including but not limited to.

Please refer to FIG. 1 to FIG. 5. FIG. 1 is a schematic diagram of the semiconductor waste gas treatment system of the invention, FIG. 2 is a schematic diagram of the application of the semiconductor waste gas treatment system of the invention to process waste gas, and FIG. 3 is the waste gas washing and treatment device of the invention. Schematic diagram of the jet-type microbubble wet exhaust gas scrubbing device. Figure 4 is a schematic diagram of the microwave plasma generation source created by the creation, and Figure 5 is a schematic diagram of the application of the created semiconductor waste gas treatment concept to the modification of the existing waste gas treatment system.

As shown in FIG. 1 to FIG. 3 , the semiconductor waste gas treatment system 10 of the present invention is composed of a vacuum extraction device 30 , a plasma treatment device 40 and an exhaust gas washing treatment device 50 . When applied to the treatment of process exhaust gas, the present invention uses a vacuum exhaust device 30 to connect the exhaust end of the process exhaust gas source 20 , and the vacuum exhaust device 30 can be located between the process exhaust gas source 20 and the vacuum exhaust device 30 during operation. A first low pressure environment is created, and the process exhaust gas 12 generated by the process exhaust gas source 20 can be sucked by generating a negative pressure. The plasma processing device 40 is disposed on the vacuum pumping device 30 (between the first pump 32 and the second pump 34 ), and through the second pump between the first pump 32 and the second pump 34 The low-pressure environment performs low-pressure plasma treatment on the process waste gas, so that the process waste gas 12 which is originally difficult to treat becomes a reaction generated gas 16 that is easier to handle, so as to be more easily dissolved in the washing liquid, and miniaturize the process waste gas 12. Particles, or even eliminate particles, to prevent clogging and easier capture. Therefore, the present invention can greatly reduce or eliminate the need to dilute the process exhaust gas. Since the gas flow rate becomes lower, the operating specifications of the vacuum pumping device 30, such as pumping power and/or pumping rate, can naturally be greatly reduced. At the same time, the first pump 32 of the vacuum pumping device establishes isolation between the plasma treatment device 40 and the process exhaust gas source 20, so that the reaction gas 16 or particles obtained after the low pressure plasma treatment cannot flow back to the process exhaust gas source 20 to cause pollution. The exhaust gas washing and processing device 50 can generate a third low-pressure environment (between the second pump 34 and the exhaust gas washing and processing device 50 ) during operation, and by generating negative pressure, the reaction gas obtained after the low-pressure plasma treatment can be effectively inhaled 16, in order to prevent clogging and backflow, and the reaction generated gas 16 can be converted into microbubbles by the washing liquid. By greatly increasing the contact area and contact time, the washing liquid can fully dissolve the reaction generated gas 16 and the particles it carries. .

To be more specific, the above-mentioned process exhaust gas source 20 is, for example, a semiconductor process chamber used for the semiconductor process, and the process exhaust gas 12 is, for example, the exhaust gas emitted from the above-mentioned semiconductor process, such as toxic exhaust gas or greenhouse gas and other exhaust gas carrying particulates. The present invention is not limited to a specific semiconductor process chamber and the type of semiconductor process it performs, as long as process waste gas 12 is generated, the semiconductor waste gas treatment system 10 of the present invention can be suitable for waste gas treatment. For example, depending on the actual semiconductor process, the process exhaust gas source 20 of the present invention can be not only a semiconductor process chamber, but also a semiconductor process chamber equipped with a turbo pump to discharge the process exhaust gas. process system. In other words, the process waste gas source 20 applicable to the semiconductor waste gas treatment system 10 of the present invention is not limited to the above examples, and any waste gas source that emits semiconductor process waste gas can be applied to the present invention. Wherein, the process exhaust gas 12 is the process exhaust gas generated in the semiconductor process, such as, but not limited to, perfluorocarbons (PFCs), nitrogen oxides (NOx), sulfur hexafluoride (SF ₆ ), nitrogen trifluoride ( NF ₃ ), ammonia (NH ₃ ), borane (B ₂ H ₆ ), hydrofluorocarbons (HFCs) and/or hydrocarbons (C _{x Hy} ) and other toxic or greenhouse gases. If the above-mentioned semiconductor process is an atomic layer deposition (ALD) process, the process waste gas is, for example, but not limited to, trimethylaluminum (TMA), tetrakis(ethylmethylamino)zirconium (TEMAZ) and/ or Tetrakis(ethylmethylamino)hafnium (TEMAH).

To be more specific, the vacuum evacuation device 30 of the semiconductor waste gas treatment system 10 of the present invention includes, for example, a two-stage combination of the first pump 32 and the second pump 34 in communication. The intake end 32a of the first pump 32 is connected to the exhaust end of the process exhaust gas source 20 through the first pipe element a1, and a first low pressure is generated in the first pipe element a1 (ie between the first pump 32 and the process exhaust gas source 20). The environment is used to extract the process exhaust gas 12 generated by the process exhaust gas source 20 . The exhaust end 32b of the first pump 32 communicates with the mixer 60, the plasma processing device 40 and the intake end 34a of the second pump 34 through the second pipe a2. The second pump 34 of the vacuum pumping device 30 establishes a second low pressure environment between the first pump 32 and the second pump 34 . The pressure of the first low pressure environment generated by the first pump 32 is, for example, about 100 torr to 10 ⁻³ torr, and the pressure of the second low pressure environment generated by the second pump 34 is, for example, about 100 torr to 10 ⁻³ torr. For example, the working pressure range of the first pump 32 is, for example, about 100 torr to 10 ⁻³ torr, and the working pressure range of the second pump 34 is, for example, about 100 torr to 10 ⁻³ torr. The first pump 32 is, for example, a pressurized pump, and the second pump 34 is, for example, a dry pump. In addition to using the first pump 32, the vacuum evacuation device 30 of the present invention also adds a second pump 34, so as to provide auxiliary suction and help to accelerate the required vacuum level, the first pump 32 simultaneously isolates the gas and particles in the second pipe a2 from flowing back to the process exhaust gas source 20 . Although the air pressure ranges of the first low pressure environment and the second low pressure environment of the vacuum evacuation device 30 and the working pressure ranges of the first pump 32 and the second pump 34 are listed as above, the scope of the present invention is not limited to this, as long as the Pu can provide a low-voltage environment, which falls within the scope of protection of this creation.

Continuing, the plasma treatment device 40 of the semiconductor waste gas treatment system 10 of the present invention is disposed between the first pump 32 and the second pump 34 of the vacuum pumping device 30 , so that the process waste gas enters the second pump 34 Before, the plasma treatment device 40 first uses the second low pressure environment generated by the second pump 34 to perform low pressure plasma treatment on the more difficult process waste gas, so as to convert the process waste gas into the more manageable reaction product gas 16 and It can miniaturize the particles carried by the process exhaust gas, so this creation can greatly reduce the blowing gas (such as nitrogen) required by the second pump 34 to dilute the process exhaust gas, and greatly reduce the power required for pumping; Micro-clogging of the vacuum extraction device. Moreover, the vacuum pumping device 30 establishes isolation between the plasma processing device 40 and the process exhaust gas source 20 , so that the reaction generated gas 16 or particles cannot flow back to the process exhaust gas source 20 to cause pollution.

In addition, the plasma processing device 40 of the present invention can selectively switch between a standby state and an operating state according to the control signal 80 . For example, when the process exhaust gas source 20 starts to discharge the process exhaust gas 12, the plasma treatment device 40 is switched from the standby state to the operating state so as to perform low-pressure plasma treatment on the process exhaust gas 12 in the second low-pressure environment; when the process exhaust gas source 20 When the discharge of the process exhaust gas 12 is stopped, the plasma processing device 40 is switched from the operating state to the standby state, and does not need to keep running at all times, so the required energy can be saved.

Specifically, the plasma processing device 40 of the present invention provides a plasma channel 42 with plasma connected to the exhaust end 32b of the first pump 32 and the intake end of the second pump 34 of the vacuum pumping device 30 Between 34a, for example, it is detachable or fixed on the second pipe member a2. The process waste gas 12 is, for example, first mixed with at least one reaction gas 14 corresponding to the process waste gas 12 , and then passes through the plasma channel 42 , so that the process waste gas 12 and the reaction gas 14 are reacted by the plasma in the plasma channel 42 , In order to convert the process exhaust gas 12 into at least one reaction generated gas 16, and to miniaturize the particles carried by the process exhaust gas 12, or even completely remove the particles. The type of the reaction gas 14 corresponds to the above-mentioned process waste gas 12, that is, the type of the reaction gas 14 is determined by the process waste gas 12, so that the process waste gas 12 and the reaction gas 14 are reacted by plasma to form a predetermined reaction generated gas 16. The above-mentioned reactive gas 14 is, for example, oxygen gas (O ₂ ), helium gas (He), argon gas (Ar), nitrogen gas (N ₂ ), hydrogen gas (H ₂ ) and/or water gas (H ₂ O) and the like. The reaction gas 16 obtained after the low-pressure plasma treatment is a harmless, stable or water-soluble gas that is easier to handle. For example _{, the mixed gas of CH 4} and CHF ₃ is treated with water gas, and the treatment efficiency (Destruction Removal Efficiency, DRE) can exceed 90%. _{For example, when NF 3 is} treated by mixing water and gas, the water gas is electronically dissociated into active particles of O, H, and OH in the plasma, which can react _{with the particles NF x from which NF 3} is dissociated by the plasma. For example: OH + NF ₂ → NOF + HF, H + NF → N + HF, H + F → HF. HF, on the other hand, can be effectively treated by wet scrubbing. Taking the radio frequency plasma generation source as an example, the electrode structure of the plasma processing device 40 can be, for example, a column shape, a plate shape, or a mesh shape, etc., as long as the plasma channel 42 having the plasma can be formed, it is suitable for the present invention.

In addition, the present invention can selectively introduce the above-mentioned reaction gas 14 through the mixer 60 according to the control signal 80 at the same time, that is, when the process waste gas source 20 starts to discharge the process waste gas 12, the reaction gas 14 is introduced, wherein the plasma treatment The plasma channel 42 of the device 40 communicates with the mixer 60 , and the process exhaust gas 12 is mixed with the reaction gas 14 by the mixer 60 , and then enters the plasma channel 42 for reaction. The mixer 60 is, for example, disposed on the second pipe a2 and in front of the air inlet 42 a of the plasma channel 42 of the plasma processing device 40 . That is, the mixer 60 has, for example, a first intake end 60a, a second intake end 60c and an exhaust end 60b connected to the mixing chamber 61, wherein the first intake end 60a of the mixer 60 is communicated with the first pump 32 The exhaust end 32b is used for introducing the process exhaust gas 12, and the exhaust end 60b of the mixer 60 is connected to the intake end 42a of the plasma channel 42 of the plasma processing device 40, and is used for exporting the mixed process exhaust gas 12 and the reaction gas 14 . The mixer 60 has, for example, a fourth pipe a4, one end of the fourth pipe a4 is connected to the mixing chamber 61 of the mixer 60, and the other end of the fourth pipe a4 has a second inlet end 60c for introducing the reaction gas 14 , so that the process exhaust gas 12 can be uniformly mixed with the reaction gas 14 in the mixing chamber 61 . The form and size of the mixer 60 and its mixing chamber 61 are not particularly limited, as long as the process exhaust gas 12 can be mixed with the reaction gas 14, it can be applied to the present invention. In addition, the mixer 60 used in the present invention may also have, for example, a regulating valve (not shown) disposed at the first inlet end 60a and the second inlet end 60c to adjust the corresponding supply of the process exhaust gas 12 and the reaction gas 14 amount in order to obtain a better response effect. In other words, the present invention can integrate the control signal 80 to ensure the operation mode of activating the plasma and inputting the mixed reaction gas only when there is process exhaust gas to be treated, so as to save energy and improve the service life of the plasma system.

Taking the plasma processing device 40 as the microwave plasma generating source, such as the microwave plasma processing device shown in FIG. 4 , as an example, the mixed gas of the process waste gas 12 and the reaction gas 14 is discharged from the exhaust end 60 b of the mixer 60 , and Entering the cylindrical microwave resonant cavity through the pipe 1 and the pipe 2, the high-power microwave (about 1,000 W to about 5,000 W) dissociates the mixed gas into a plasma state in the plasma channel 42 . Under low pressure, electrons can get enough energy to collide with gas molecules for dissociation reaction. At the same time, the generated molecules, atoms and activated particles also produce various chemical and physical reactions to achieve the goal of waste gas treatment. The reaction gas 16 obtained after the low-pressure plasma treatment enters the second pump 34 through the pipeline 3 and the pipeline 4 . Specifically, the cylindrical microwave resonant cavity of the microwave plasma generating source includes a metal coupling antenna 6 , a ceramic tube 7 and a cylinder 8 arranged coaxially, wherein the ceramic tube 7 is located in the center of the hollow cylinder 8 and the antenna 6 is located in the center of the ceramic tube 7 . In the center, the microwave source 5 is arranged on the ceramic tube 7 and is located on one side of the antenna 6 .

The above-mentioned microwave plasma processing apparatus adopts the structure of a coaxial microwave resonant cavity, and its advantage lies in that the reaction length of the microwave and the plasma can be lengthened to achieve the goal of uniform distribution of the plasma. Generally, the plasma of the cylindrical or rectangular microwave resonator is often concentrated near the entrance, and cannot effectively form a uniform plasma. The coaxial microwave distribution is achieved by the microwave source 5 via the metal coupled antenna 6 and the ceramic tube 7 and the outer cylinder 8 . The ceramic tube 7 can effectively transmit microwaves on the antenna 6 without causing the microwave source coupled plasma reaction to concentrate near the inlet, and at the same time achieve the functions of isolating the vacuum and protecting the antenna 6 from being damaged by the plasma. However, the type of the plasma processing device 40 of the present invention is not limited to the above-mentioned microwave plasma generating source, and any existing technology such as a radio frequency plasma generating source or a high-voltage discharging source can be used, as long as the plasma channel 42 can be formed in a low-voltage environment. Making the process waste gas 12 react with the reaction gas 14 can be applied to the present invention.

The exhaust gas washing and processing device 50 of the semiconductor exhaust gas treatment system 10 of the present invention uses the Venturi throat principle to make the jet structure spray out the washing liquid 59 to generate the above-mentioned between the second pump 34 and the exhaust gas washing and processing device 50 . The third low pressure environment is used to inhale the reaction generated gas 16 obtained after the low pressure plasma treatment, and convert the reaction generated gas 16 into microbubbles. By greatly increasing the contact area and contact time, the washing solution can be fully dissolved and reacted By generating gas 16 and capturing particles, the invention can prevent clogging of the vacuum extraction device, effectively prolong the maintenance period, and prevent backflow pollution, so it can save energy, protect the environment, and treat process waste gas stably. Specifically, as shown in FIG. 3 , the exhaust gas scrubbing treatment device 50 used in the present invention is an example of a jet-type micro-bubble wet exhaust gas scrubber using the Venturi tube principle. Among them, the exhaust gas washing and treatment device 50 uses the negative pressure jet pipe 51 to spray the washing liquid 59 vertically at a high speed and generate a third low pressure environment (negative pressure of about 400 torr to 600 torr), so as to use the third pipe a3 to pass through the second pump 34 The reaction product gas 16 converted from the process waste gas 12 is sucked. The volume of the washing liquid 59 is, for example, about 50% to 90% of the volume of the inner tank 53 of the treatment tank, preferably about 60% to 80%, and more preferably about 70%. Moreover, when the cleaning liquid 59 is impacted downward by the negative pressure jet pipe 51 at a high speed to the cleaning liquid 59 in the inner tank 53 of the processing tank, the reaction generated gas 16 will be cut to form a plurality of microbubbles in the cleaning liquid 59 (average diameter is less than about 1.0 mm), its size is much smaller than traditional bubbles, so the surface area is much larger than traditional bubbles, and in the process of micro-bubble moving upward from the depth of the washing liquid 59 in the inner tank 53 of the treatment tank, due to the contact area and contact The time is greatly increased so that the microbubbles can fully contact the washing liquid 59 . Because the reaction gas 16 will dissolve in the washing liquid 59 , the microbubbles will gradually decrease in volume during the rising process, and then disappear into the washing liquid 59 . The water vapor of the washing liquid 59 raised by the micro-bubbles will overflow into the outer tank 54 . The scrubbing liquid 59 contains chemicals for treating the corresponding reaction gas 16 . Chemicals such as, but not limited to, are selected from the group consisting of brine solution, sodium hydroxide, calcium hydroxide, calcium carbonate and sodium bicarbonate. That is, the composition of the scrubbing liquid 59 may be determined by the reaction product gas 16 to be treated, and a suitable alkali may be used for neutralization to reduce the formation of an acidic solution, such as fresh water and sodium hydroxide or other neutralizing agent such as lime. The formed solution can effectively extract and neutralize a large amount of HCl, SO ₂ or other acid-containing components in the reaction gas 16 . _{Calcium hydroxide (Ca(OH) 2} ), calcium carbonate (CaCO ₃ ), and/or sodium bicarbonate (NaHCO ₃ ), such as calcium hydroxide (Ca(OH) 2 ), can also be mixed with scrubbing liquid 59 to help absorb other acidic process off-gases from various production sources. Therefore, in the process that the microbubbles are in contact with the cleaning solution 59, the reaction gas 16 can be sufficiently dissolved in the cleaning solution 59, and the cleaning solution 59 can sufficiently capture the particles.

Subsequently, the washed gas that is not dissolved by the washing liquid 59 diffuses to the liquid surface of the inner tank 53 along with the washing liquid 59 to form water vapor. Therefore, the gas-liquid separation component 56 above the inner tank 53 can filter and capture the water vapor. and only allow the above-mentioned cleaned gas to pass through the gas-liquid separation component 56, so the dried and cleaned gas that has been processed can be discharged from the discharge channel 57 to, for example, a central waste gas treatment system. In addition, the above-mentioned gas-liquid separation component can also be added to the discharge channel 57 to discharge the drier washed gas by capturing the water vapor. The above-mentioned gas-liquid separation element 56 can be any structure capable of separating liquid and gas, such as a fiber bed mist eliminator composed of glass fibers with a diameter of about 100 microns to 1 micron, so as to filter water and gas and only allow gas to pass through it. . As for the washing liquid 59 blocked by the gas-liquid separation element 56 , it will drop into the outer tank 54 . Then, the washing liquid 59 in the outer tank 54 of the treatment tank can be filtered by, for example, the filter assembly 55 , and the filtered washing liquid 59 in the outer tank 54 can be re-injected into the inner tank of the treatment tank through the negative pressure jet pipe 51 by the water pump 58 . In 53 , a plurality of microbubbles are formed in the washing liquid 59 by cyclically generating negative pressure and cutting the reaction generated gas 16 .

The above-mentioned negative pressure jet pipe 51 has, for example, a suction cavity 72 and an injection pipe 74. The side wall of the suction cavity 72 has at least one suction port for communicating with the third pipe member a3 through the gas pipeline 52. The top of the injection pipe 74 is an injection port. To inject the washing liquid 59 , the bottom end of the spray pipe 74 is an outlet and extends to the interior of the suction cavity 72 , and by spraying the washing liquid 59 into the suction cavity 72 , a negative pressure suction force is generated. The gas pipeline 52 can be, for example, vertically or obliquely arranged on the side wall of the suction cavity 72 , and the gas pipeline 52 is preferably arranged on the side wall of the suction cavity 72 obliquely. The bottom of the suction chamber 72 is connected with a mixing tube 76 and a diffusing tube 78 in sequence, and the mixing tube 76 and/or the diffusing tube 78 are immersed in the washing liquid 59 of the inner tank 53, preferably so that the micro-bubbles can pass through The momentum of the downward jet impact reaches the bottom of the inner tank 53, and then moves upward from the bottom, so as to increase the time for the microbubbles to contact the washing liquid 59. The time for the microbubbles to pass through the washing liquid 59 is, for example, about 1 to 20 seconds. Preferably, it is about 1 to 10 seconds. Besides, the cavity wall of the suction cavity 72 and/or the gas pipeline 52 can optionally have cleaning elements, such as nozzles, for example, to spray the cleaning liquid 59 first, and then spray the air, so as to clean the inside of the cavity wall. Effective, and can keep the suction cavity 72 and/or the cavity wall of the gas pipeline 52 dry. In addition, the cleaning element is preferably along the tangential direction of the cavity wall of the suction cavity 72 and/or the gas pipeline 52 and slightly inclined to sequentially spray the cleaning liquid 59 and the air into the suction cavity 72 and/or the gas pipeline 52 at a high speed. In order to generate a spiral airflow flowing from top to bottom along the suction chamber 72 and/or the gas pipeline 52, the generation of deposits can be effectively prevented.

Since the process exhaust gas generated by the semiconductor process will carry a large amount of particles, in order to avoid blockages in the traditional technology, such as the blockage of the vacuum pumping device, a large amount of purge gas (such as nitrogen) must be used to dilute the pumping gas (ie process exhaust gas), In order to prevent the blockage problem, it is necessary to use a pump with a higher operating specification for pumping, which increases the operating cost and consumes energy. Compared with conventional technologies, this creation can greatly reduce or eliminate the need to dilute process exhaust gas, and can also greatly reduce required operating specifications, such as pumping power or pumping rate. In this invention, before the process exhaust gas enters the second pump 34, the process exhaust gas 12 is pre-treated by the plasma treatment device 40, which can effectively decompose the chemical bonds of the precursors to reduce the possibility of generating particles, and make the reaction generated gas 16 become gas Mutually. In other words, the present invention can not only convert the process waste gas 12 into the reaction gas 16 that is harmless, stable or more easily dissolved in the washing liquid, but also can reduce the size of the solid particles so that they can be easily captured by the washing liquid, and even completely remove the particles, Therefore, this creation is not prone to blockage. From this, it can be seen that this creation can use a lower pumping power, prolong the maintenance period, and prevent secondary pollution of the environment, and the semiconductor waste gas treatment system of this creation performs plasma treatment under the condition of low air pressure, and the components are damaged. The rate is lower and more stable. Therefore, the present invention can achieve the effects of energy saving, environmental protection and stable treatment of process waste gas.

In addition, the exhaust gas scrubbing treatment device 50 of the present invention can not only process the reaction gas 16, but also generate a third low-pressure environment, which can provide negative pressure suction, reduce the power required for the operation of the vacuum pumping device 30, and avoid The vacuum evacuation device 30 is blocked. Specifically, the inlet end 50a of the exhaust gas washing and treatment device 50 is connected to the exhaust end 34b of the second pump 34 of the vacuum pumping device 30 through the third pipe a3 to inhale the reaction gas 16 . Wherein, the exhaust gas scrubbing treatment device 50 is, for example, a wet exhaust gas scrubbing processor and/or a dry exhaust gas scrubbing processor. The exhaust gas scrubbing treatment device 50 of the present invention is preferably a wet exhaust gas scrubber that can provide negative pressure suction, and more preferably a jet-type microbubble wet exhaust gas scrubbing device, which can generate a rough vacuum state (about 400 torr-600 torr ) of the third low pressure environment. Since the exhaust gas washing and treating device 50 is connected to the second pump 34, the negative pressure suction generated by the exhaust gas washing and treating device 50 between the second pump 34 and the exhaust gas washing and treating device 50 can provide auxiliary suction, which is helpful for the reaction generation The gas 16 is discharged into the exhaust gas scrubbing treatment device 50 via the second pump 34 . In other words, by virtue of the negative pressure suction generated by the exhaust gas scrubbing treatment device 50, the present invention can prevent the reaction generated gas 16 and particles obtained after the low-pressure plasma treatment from being backflowed, and can prevent the second pump 34 from being blocked. And reduce the power required for the operation of the vacuum evacuation device 30 .

In addition, according to the concept of semiconductor waste gas treatment in this creation, as shown in Figure 5, this creation can be applied to modify the existing waste gas treatment system. The pump (ie the first pump 32 ) and the dry pump (ie the second pump 34 ) are added into the gas mixer (ie the mixer 60 ) and the plasma treatment device 40 , and the jet type microbubble wet exhaust gas washing device is added at the same time. The local exhaust gas treatment system replaces the existing electric heating or combustion local exhaust gas treatment system.

To sum up, the semiconductor waste gas treatment system of the present invention adopts a low pressure plasma treatment device, which has the following advantages:

(1) The vacuum pumping device can generate a first low pressure environment to extract the process exhaust gas generated by the process exhaust gas source. The vacuum pumping device can form a second low pressure environment between the first pump and the second pump, and the plasma The treatment device can simultaneously use the second low pressure environment to perform low pressure plasma treatment on the process exhaust gas. In addition, the plasma processing device can be switched from the standby state to the running state only when the process exhaust gas starts to be discharged, so as to save energy.

(2) The exhaust gas scrubbing treatment device is a jet micro-bubble wet exhaust gas scrubbing device. When the scrubbing liquid is sprayed at a high speed, the reaction gas obtained after the low-pressure plasma treatment can be converted into micro-bubbles, which greatly increases the contact area and contact time. , which helps to dissolve the above-mentioned reaction gas and capture particles, and can simultaneously generate a rough vacuum state between about 400torr to 600torr at the air inlet, so as to inhale the above-mentioned reaction gas and particles for washing, and avoid vacuum. The suction device is blocked, improving the operating efficiency of the vacuum pumping device and reducing the required power.

(3) By setting up a plasma treatment device to treat the process exhaust gas before the harmful process exhaust gas enters the second pump (dry pump), it can greatly reduce the introduction of nitrogen to dilute the toxic gas or even do not need to introduce nitrogen, so it can reduce nitrogen The generation of oxides and carbon monoxide avoids secondary pollution and can reduce the required operating specifications such as pumping power and pumping flow.

(4) By introducing the corresponding reactive gases, such as oxygen and water, stable precursors, such as oxides, can be formed, which can effectively make the more difficult process waste gas form a more manageable reaction gas, and miniaturize the particles, Even eliminate particulates, thereby reducing toxic and greenhouse gases.

(5) Plasma treatment device is installed after the first pump of the vacuum extraction device, which can effectively prevent the reaction gas and particles obtained after plasma treatment from flowing back into the process waste gas source, and then the second pump and waste gas washing. The treatment device can also provide negative pressure suction, which is more helpful to prevent the backflow of reaction gas and particles into the process exhaust gas source and to prevent clogging.

(6) The plasma treatment device can effectively decompose the chemical bonds of the precursors in the atomic layer deposition (ALD) process, and can make the reaction gas into the gas phase to reduce the possibility of generating particles, so it can effectively prolong the maintenance period.

(7) The plasma processing device can use the structure of a coaxial microwave resonant cavity. The power used is, for example, between 1,000W and 5,000W, depending on the type of waste gas and the flow rate.

The above description is exemplary only, not limiting. Any equivalent modifications or changes that do not depart from the spirit and scope of this creation should be included in the scope of the appended patent application.

FIG. 1 is a schematic diagram of the created semiconductor waste gas treatment system.

FIG. 2 is a schematic diagram of the application of the invented semiconductor waste gas treatment system in the treatment of process waste gas.

FIG. 3 is a schematic diagram of a jet-type micro-bubble wet exhaust gas scrubbing device used in the exhaust gas scrubbing treatment device of the present invention.

Fig. 4 is a schematic diagram of a plasma processing apparatus using a microwave plasma generating source, wherein Fig. 4(B) is a schematic diagram obtained along the section line I-I' of Fig. 4(A).

Figure 5 is a schematic diagram of the application of the invented semiconductor waste gas treatment concept to the modification of the existing waste gas treatment system.

10: Semiconductor waste gas treatment system

12: Process waste gas

14: Reactive gas

16: Reaction produces gas

30: Vacuum beat air device

32: First Pump

32a: Intake end

32b: exhaust end

34: Second Pump

34a: Intake end

34b: exhaust end

40: Plasma processing device

42a: Intake end

42: Plasma channel

50: Exhaust gas scrubbing treatment device

50a: Intake end

60: Mixer

60a: First intake end

60b: Exhaust end

60c: Second intake end

61: Mixing chamber

a1: The first pipe fitting

a2: Second pipe fitting

a3: The third pipe fitting

a4: Fourth pipe fitting

80: Control signal

Claims (18)

A semiconductor waste gas treatment system, suitable for treating at least one process waste gas generated by a process waste gas source, is characterized in that: The semiconductor waste gas treatment system is composed of a vacuum pumping device, a plasma treatment device and a waste gas washing treatment device; Wherein, the vacuum extraction device adopts a two-stage combination of a first pump and a second pump, and the first pump generates a first low-pressure environment for extracting the process exhaust gas generated by the process exhaust gas source, The second pump generates a second low pressure environment between the first pump and the second pump; Wherein, the plasma processing device is arranged between the first pump and the second pump, so that the plasma processing device is placed in the second low pressure environment before the process exhaust gas enters the second pump subjecting the process off-gas to a low pressure plasma treatment to convert the process off-gas into a reactive gas and to miniaturize or remove a plurality of particles carried by the process off-gas; and Wherein, the exhaust gas washing and treating device generates a third low-pressure environment between the second pump and the exhaust gas washing and treating device by spraying a washing liquid, so as to inhale the low-pressure plasma treatment through the second pump The obtained reaction generated gas and the particles, and the reaction generated gas is cut into a plurality of microbubbles by the sprayed washing liquid, so that the washing liquid fully dissolves the reaction generated gas and captures the reaction generated gas. some particles. The semiconductor waste gas treatment system according to claim 1, wherein the first pump of the vacuum pumping device is disposed between the process waste gas source and the plasma treatment device, so as to isolate the low pressure by the first pump The reaction gas obtained after plasma treatment and the particles carried by it can prevent backflow and contaminate the exhaust gas source of the process. The semiconductor exhaust gas treatment system of claim 1, wherein the plasma treatment device is switched between a standby state and an operating state according to a control signal, and when the process exhaust gas source starts to discharge the process exhaust gas, the plasma The processing device is switched from the standby state to the operating state so as to perform the low pressure plasma treatment on the process exhaust gas in the second low pressure environment. When the process exhaust gas source stops discharging the process exhaust gas, the plasma treatment device is Switch from the operating state to the standby state. The semiconductor waste gas treatment system of claim 3, wherein when the plasma treatment device performs the low-pressure plasma treatment on the process waste gas, the process waste gas is first mixed with a reaction gas according to the control signal. The semiconductor waste gas treatment system according to claim 4, wherein the plasma treatment device uses a mixer to introduce the reaction gas, so that the reaction gas is mixed with the process waste gas. The semiconductor waste gas treatment system according to claim 1, wherein the process waste gas is perfluorocarbons (PFCs), nitrogen oxides (NOx), sulfur hexafluoride (SF ₆ ), nitrogen trifluoride (NF ₃ ), ammonia (NH _3), diborane (B ₂ H _6), hydrofluorocarbons (HFCs), hydrocarbons (C _x H _y) and / or CCl _4. The semiconductor waste gas treatment system according to claim 1, wherein if the process waste gas source is subjected to an atomic layer deposition (ALD) process, the process waste gas is trimethylaluminum (TMA), tetrakis(ethylmethylamino)zirconium (TEMAZ) and/or tetrakis(ethylmethylamino)hafnium (TEMAH). The semiconductor waste gas treatment system according to claim 6 or 7, wherein the reactive gas is oxygen (O ₂ ), helium (He), argon (Ar), nitrogen (N ₂ ), hydrogen (H ₂ ) and/or or water vapor (H ₂ O). The semiconductor exhaust gas treatment system according to claim 1, wherein the first pump is a pressurized pump, and the second pump is a dry pump. The semiconductor waste gas treatment system according to claim 1, wherein the air pressure of the first low pressure environment generated by the first pump of the vacuum pumping device is 100 torr to 10 ⁻³ torr. The semiconductor waste gas treatment system according to claim 1, wherein the gas pressure of the second low pressure environment generated by the second pump of the vacuum pumping device is 100 torr to 10 ⁻³ torr. The semiconductor exhaust gas treatment system according to claim 1, wherein the air pressure of the third low-pressure environment generated by the exhaust gas scrubbing treatment device is 400 torr to 600 torr. The semiconductor exhaust gas treatment system as claimed in claim 1, wherein the exhaust gas scrubbing treatment device comprises: a treatment tank, comprising an inner tank and an outer tank for containing the washing liquid; and a jet tube, wherein the washing liquid is injected into the inner tank of the processing tank through the jet tube, so as to cut the reaction gas to form the micro-bubbles to be dissolved in the washing liquid, and then the micro-bubbles are lifted up The water vapor of the washing liquid overflows into the outer tank. The semiconductor waste gas treatment system according to claim 1, wherein the plasma treatment device is a radio frequency plasma generation source, a microwave plasma generation source or a high voltage discharge source. The semiconductor waste gas treatment system according to claim 1, wherein the plasma treatment device is a microwave plasma generation source having a coaxial microwave resonant cavity. The semiconductor waste gas treatment system of claim 15, wherein the microwave plasma generating source comprises a microwave source, a metal coupling antenna arranged coaxially, a ceramic tube and a hollow cylinder, wherein the ceramic tube is located in the center of the cylinder And the metal coupling antenna is located in the center of the ceramic tube, and the microwave source is arranged on the ceramic tube and is located at one side of the metal coupling antenna. The semiconductor exhaust gas treatment system of claim 15, wherein the power of the microwave plasma generating source is between 1,000W and 5,000W. The semiconductor waste gas treatment system of claim 1, wherein the process waste gas source is a semiconductor process chamber or a turbo vacuum pump connected to the semiconductor process chamber to discharge the process waste gas.

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