Hot airflow baking system capable of obtaining ultrahigh vacuum

Abstract

The utility model belongs to the technical field of vacuum acquisition, and particularly discloses a hot airflow baking system for acquiring ultrahigh vacuum, which comprises a vacuum cavity, a hot airflow baking system and a vacuum acquisition system, a flushing pipeline is arranged in the vacuum cavity, and the vacuum cavity is connected with the flushing pipeline through a flange interface; the hot air baking system comprises an air source steel cylinder, a pressure reducing valve, a pressure gauge, a first knob valve, a purifier, a second knob valve, a heater, an air valve and a diffuser which are sequentially connected through pipelines according to the air flow direction, and the air outlet end of the diffuser is connected with the flange connector of the vacuum cavity through a pipeline; the vacuum obtaining system comprises a butterfly valve, a molecular pump, a backing valve, a Pirani gauge, a roots pump set and a rough pumping valve arranged on the roots pump set, wherein the butterfly valve, the molecular pump, the backing valve, the Pirani gauge, the roots pump set and the rough pumping valve are sequentially connected, and the butterfly valve is connected with a vacuum obtaining connector of the vacuum cavity. A detection interface, a gas analysis interface, a pressure relief interface and a waste discharge port are formed in the side edge of the vacuum cavity.

Description

Technical Field

[0001] The utility model relates to the technical field of vacuum acquisition, in particular to a hot gas flow baking system for obtaining ultra-high vacuum. Background Technique

[0002] The electron beam detection technology is carried out under high vacuum conditions. The indexes of the vacuum system directly affect the cathode life and the stability of the emission current. A stable electron beam current is one of the basic conditions for obtaining high-quality exposure patterns, which requires that the entire electron beam channel, including the vacuum cavity of the workbench for placing silicon wafers or masks, should have a "clean" vacuum degree and provide an ultra-high vacuum environment at the same time. At present, the electron beam detection technology generally adopts the combination of vacuum technology and technologies such as molecular pumps, Roots pumps and ion pumps, and cooperates with strict clean vacuum processes to improve the vacuum value of the system.

[0003] During the debugging process of the electron beam detection machine, it is often necessary to open the vacuum cavity to upgrade the software and hardware or locate and troubleshoot problems. As the cavity is exposed to the atmosphere, the vacuum cavity and its internal components will re-adsorb a large amount of gas and impurities. Therefore, the next experimental debugging requires waiting for a slow and long water vapor analysis process, and only after reaching the required vacuum index can the next step of joint debugging and drawing be carried out, which greatly increases the time for obtaining the working vacuum. Content of the Utility Model

[0004] The purpose of the utility model is to provide a hot gas flow baking system for obtaining ultra-high vacuum, so as to solve the problems raised in the above background technique.

[0005] To achieve the above purpose, the utility model provides the following technical solution: A hot gas flow baking system for obtaining ultra-high vacuum, including a vacuum cavity, a hot gas flow baking system and a vacuum acquisition system. A flushing pipeline is arranged inside the vacuum cavity, and the vacuum cavity is connected to the flushing pipeline through a flange interface;

[0006] The hot gas flow baking system includes a gas source cylinder, a pressure reducing valve, a pressure gauge, a first knob valve, a purifier, a second knob valve, a heater, a wind valve and a diffuser connected in sequence through pipelines according to the gas flow direction. The outlet end of the diffuser is connected to the flange interface of the vacuum cavity through a pipeline;

[0007] The vacuum acquisition system includes a butterfly valve, a molecular pump, a fore-vacuum valve, a Pirani gauge and a Roots pump set connected in sequence, wherein the butterfly valve is connected to the vacuum acquisition interface of the vacuum cavity;

[0008] A detection interface, a gas analysis interface, a pressure relief interface and a waste discharge port are arranged on the side of the vacuum cavity. A vacuum gauge is installed on the detection interface, a gas analyzer is installed on the gas analysis interface, a pressure relief valve is arranged on the pressure relief interface, and a waste discharge valve is arranged on the waste discharge port.

[0009] Preferably, the external interfaces of the heater, purifier, diffuser, first knob valve and second knob valve adopt the VCR connection method, with the functions of vacuum sealing and SEMI certification.

[0010] Preferably, the outside of the purifier is wrapped with a fiberglass insulation layer and a Teflon outer protective layer, and metal hose pipe fittings are used between the gas outlet end of the purifier and the gas-using point, which is easy for pipeline layout.

[0011] Preferably, the outer shell of the heater is made of low-magnetic material SUS316, and the inside is a nickel-based alloy spiral heating tube, which increases the path of gas heating and the uniformity of the outlet gas temperature; improves the heating speed of the high-purity nitrogen heater and meets the nitrogen consumption demand with a high-temperature high-purity nitrogen supply.

[0012] The heater is a component with a high degree of automation, suitable for the semiconductor process field, with 485 communication function. When the Scrubber fails, the gas supply is cut off; it has functions such as an alarm history management module.

[0013] Preferably, the flushing pipeline is installed at the top and side of the vacuum cavity, and sudden expansion diffuser flushing outlets are evenly arranged on the flushing pipeline.

[0014] Compared with the prior art, the beneficial effects of the present utility model are:

[0015] The present utility model rapidly heats the surfaces of the internal components of the vacuum cavity through a hot air flow baking system and a vacuum acquisition system, assisted by high-purity nitrogen to wash away the residual components on the inner surface of the cavity, and displace the processed gas out of the vacuum cavity. Combined with the vacuum acquisition system, it is repeatedly carried out to accelerate the acquisition of ultra-high clean vacuum, maintain the high-clean environment of the cavity, shorten the test cycle of the vacuum cavity, greatly improve the working efficiency of the vacuum cavity, and speed up the test rhythm of the machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present utility model.

[0017] In the figure: 1, gas source cylinder; 2, pressure reducing valve; 3, pressure gauge; 4, first knob valve; 5, purifier; 6, second knob valve; 7, heater; 8, air valve; 9, diffuser; 10, vacuum cavity; 11, butterfly valve; 12, molecular pump; 13, fore valve; 14, Pirani gauge; 15, flushing pipeline; 16, vacuum gauge; 17, gas analyzer; 18, pressure relief valve; 19, waste discharge valve; 20, Roots pump set. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0019] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "vertical", "upper", "lower", "horizontal", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0020] In the description of the present utility model, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "installed", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0021] Please refer to Figure 1 , the present utility model provides a technical solution: a hot gas flow baking system for obtaining ultra-high vacuum, including a vacuum chamber 10, a hot gas flow baking system, and a vacuum acquisition system. A flushing pipeline 15 is arranged inside the vacuum chamber 10, and the vacuum chamber 10 is connected to the flushing pipeline 15 through a flange interface.

[0022] Furthermore, the hot gas flow baking system includes a gas source cylinder 1, a pressure reducing valve 2, a pressure gauge 3, a first knob valve 4, a purifier 5, a second knob valve 6, a heater 7, a wind valve 8, and a diffuser 9 that are sequentially connected through pipelines according to the gas flow direction. The outlet end of the diffuser 9 is connected to the flange interface of the vacuum chamber 10 through a pipeline.

[0023] Furthermore, the vacuum acquisition system includes a butterfly valve 11, a molecular pump 12, a fore-vacuum valve 13, a Pirani gauge 14, and a Roots pump set 20 that are sequentially connected. The butterfly valve 11 is connected to the vacuum acquisition interface of the vacuum chamber 10.

[0024] Further, a detection interface, a gas analysis interface, a pressure relief interface, and a waste discharge port are provided on the side of the vacuum chamber 10. A vacuum gauge 16 is installed on the detection interface, a gas analyzer 17 is installed on the gas analysis interface, a pressure relief valve 18 is provided on the pressure relief interface, and a waste discharge valve 19 is provided on the waste discharge port.

[0025] Further, the external interfaces of the heater 7, the purifier 5, the diffuser 9, the first knob valve 4, and the second knob valve 6 adopt the VCR connection method, which has the function of vacuum sealing and a SEMI certification certificate.

[0026] Further, the purifier 5 is externally wrapped with a fiberglass insulation layer and a Teflon outer protective layer. A metal hose pipe fitting is used between the gas outlet end of the purifier 5 and the gas usage point, which is convenient for pipeline layout.

[0027] Further, the outer shell of the heater 7 is made of a low-magnetic material SUS316, and the inside is a nickel-based alloy spiral heating tube, which increases the path of the gas being heated and the uniformity of the outlet gas temperature; improves the heating speed of the high-purity nitrogen heater 7 and meets the nitrogen usage demand with the supply of high-temperature high-purity nitrogen.

[0028] Further, the heater 7 is a component with a high degree of automation, suitable for the semiconductor process field. It has a 485 communication function. When a Scrubber failure occurs, the gas supply is cut off; it has functions such as an alarm history management module.

[0029] Further, the flushing pipeline 15 is installed at the top and side inside the vacuum chamber 10, and sudden expansion and diffuser flushing outlets are evenly arranged on the flushing pipeline 15.

[0030] In summary, when the present device is in use, it includes the following steps:

[0031] Step 1: Conduct a safety inspection on the hot gas flow baking system, and perform a pressure holding and vacuum negative pressure leak rate test.

[0032] Step 2: Sequentially open the gas source pressure reducing valve 2, the purifier 5, the first knob valve 4, the second knob valve 6, the air valve 8, and the waste discharge valve 19 on the gas source cylinder 1 and adjust them so that the pressure at the inlet of each pressure regulating point in the pipeline is 1.2 - 1.5 bar, and perform a micro-positive pressure nitrogen flushing for 10 minutes.

[0033] Step 3: Close the waste discharge valve 19 and the air valve 8, open the gas heater 7, and adjust the heating temperature to 150 °C, that is, start the heater 7 to preheat the gas.

[0034] Step 4: After preheating to the specified temperature, start the Roots pump set 20, and then open the foreline valve 13 and the butterfly valve 11. After the pump set operates stably, open the air valve 8, and synchronously adjust the pressure reducing valves 2 and 4 of the hot air flow baking system so that the vacuum degree of the vacuum chamber 10 is maintained at 1000 - 3000 Pa, and keep the temperature of the heater 7 stable at 150 °C, with the hot air flow flushing time lasting for 10 min;

[0035] Step 5: Close the air valve 8. When the chamber vacuum is < 10 Pa, open the air valve 8 again, heat and flush with hot nitrogen at 150 °C until the chamber vacuum reaches 3000 Pa. Repeat Step 5 for 5 - 10 times.

[0036] Step 6: After performing Step 5, close the air valve 8, keep the Roots pump set 20, the foreline valve 13, and the butterfly valve 11 in the open state. When the chamber vacuum is < 10 Pa, open the molecular pump 12 to obtain the ultimate vacuum.

[0037] It should be noted that: The entire device is controlled through the total control button. Since the devices matched with the control button are common devices and belong to the existing mature technologies, the electrical connection relationship and the specific circuit structure are not elaborated herein.

[0038] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hot air flow baking system for obtaining ultra-high vacuum, characterized in that: It comprises a vacuum cavity (10), a hot air flow baking system and a vacuum obtaining system, wherein a flushing pipe (15) is arranged inside the vacuum cavity (10), and the vacuum cavity (10) is connected to the flushing pipe (15) via a flange interface; The hot air flow baking system comprises a gas source cylinder (1), a pressure reducing valve (2), a pressure gauge (3), a first knob valve (4), a purifier (5), a second knob valve (6), a heater (7), a wind valve (8) and a diffuser (9) which are connected in sequence through pipelines according to the gas flow direction, wherein the gas outlet end of the diffuser (9) is connected to the flange interface of the vacuum chamber (10) through a pipeline; The vacuum acquisition system comprises a butterfly valve (11), a molecular pump (12), a fore valve (13), a Pirani gauge (14) and a Roots pump group (20) which are connected in sequence, wherein the butterfly valve (11) is connected to a vacuum acquisition interface of a vacuum chamber (10); The vacuum chamber (10) is provided with a detection interface, a gas analysis interface, a pressure relief interface and a waste outlet on the side thereof; a vacuum gauge (16) is installed on the detection interface, a gas analyzer (17) is installed on the gas analysis interface, a pressure relief valve (18) is provided on the pressure relief interface, and a waste outlet is provided with a waste valve (19).

2. The hot air flow baking system for obtaining ultra-high vacuum according to claim 1, characterized in that: The external interfaces of the heater (7), the purifier (5), the diffuser (9), the first knob valve (4) and the second knob valve (6) are connected in a VCR manner.

3. The hot air flow baking system for obtaining ultra-high vacuum according to claim 1, characterized in that: The purifier (5) is externally wrapped with a glass fiber insulation layer and a Teflon outer protective layer.

4. The hot air flow baking system for obtaining ultra-high vacuum according to claim 1, characterized in that: The outer shell of the heater (7) is made of the low-magnetic material SUS316, and the interior is a nickel-based alloy spiral heating tube.

5. The hot air flow baking system for obtaining ultra-high vacuum according to claim 1, characterized in that: The flushing pipeline (15) is installed at the top and the side of the vacuum chamber (10), and sudden expansion and pressure diffusion flushing outlets are evenly arranged on the flushing pipeline (15).

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