Low vapor pressure liquid gas supply device and method

Abstract

The invention relates to a low vapor pressure liquid gas supply device and method, the structure is that a storage tank is connected with a preheating box, the preheating box is connected with an evaporation heating tank, and the evaporation heating tank is connected with a process end. The preheating box heats the liquid gas to 3-5 DEG C below the steam boiling point temperature; the preheated and uniformly heated liquid gas is conveyed into an evaporation heating tank, and is heated in an electric heating manner until the evaporation boiling point temperature of the liquid gas is 10-15 DEG C or above; liquid gas is heated through the second-stage heating system, and stable evaporation temperature and pressure and flow meeting process requirements can be obtained. The device has the advantages that thermodynamic and fluid accounting is met, and the requirements of stable pressure and large-flow supply are met at a stable evaporation temperature on the premise of ensuring that liquid gas is uniformly heated in two sections. Gas such as argon or helium does not need to be introduced into the evaporation tank to increase the evaporation capacity, corresponding process pipeline valves are omitted, and the use cost and the equipment energy consumption can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to a liquid gas supply device and method, and in particular to a device and method for supplying low vapor pressure liquid gas. Background Art

[0002] In the semiconductor manufacturing process epitaxy, chemical vapor deposition, etching, and doping processes, pyrophoric, highly toxic, and corrosive high-purity special gases are required. In the actual supply of special gases, gases such as SiCl4, GeCl4, BCl3, SiHCl3, and TEOS are low-vapor-pressure gases, that is, the saturated vapor pressure at room temperature is less than 0.2Mpa. Since the saturated vapor pressure of these gases is low and the required evaporation temperature is high, during the transportation process, the temperature changes and cooling cause liquefaction and transportation difficulties. In the application of the prior art special gas system, while heating the liquid gas, inert argon or helium is introduced into the bottom of the evaporation container, and liquid bubbles are formed by blowing to increase the evaporation amount to meet the machine usage requirements. At the same time, due to the temperature difference caused by the fluctuation of the liquid level inside the evaporation container during use, it is difficult to obtain a stable evaporation temperature, and the liquid bubbles formed by the blowing are prone to coalesce, resulting in low evaporation efficiency, which greatly limits the large-flow supply of low vapor pressure liquid gas and increases the cost of use. Summary of the invention

[0003] The present invention proposes a low vapor pressure liquid gas supply device and method, the purpose of which is to overcome the above-mentioned deficiencies in the prior art, while meeting the requirements of pressure stabilization and large flow supply of low vapor pressure liquid gas, reducing the use cost and energy consumption.

[0004] The technical solution of the present invention is a low vapor pressure liquid gas supply device, which includes a storage tank, a preheating box, an evaporation heating tank and a process end, wherein the storage tank outlet is connected to the preheating box inlet through a delivery pipeline, the preheating box outlet is connected to the evaporation heating tank inlet through a first electric heating insulation pipeline, and the evaporation heating tank outlet is connected to the process end through a second electric heating insulation pipeline. By heating the liquid gas through the secondary heating system, a stable evaporation temperature and a pressure and flow rate that meet the process requirements can be obtained.

[0005] Preferably, the inner side of the preheating box and the inner side of the evaporation heating tank are both made of quartz insulation material, which can keep heat and reduce thermal attenuation.

[0006] Preferably, the inner surface Ra of the preheating box is less than 0.1 µm, which can increase heat radiation and improve thermal efficiency.

[0007] Preferably, the conveying pipeline is provided with a first pneumatic diaphragm valve near the storage tank, the conveying pipeline is provided with a first isolation valve near the preheating box, the first electric heating and insulation pipeline is provided with a second isolation valve, a second pneumatic diaphragm valve and a third isolation valve in sequence from one end near the preheating box to one end near the evaporative heating tank, and the second electric heating and insulation pipeline is provided with a fourth isolation valve, a temperature sensor, a third pneumatic diaphragm valve and a mass flow controller in sequence from one end near the evaporative heating tank to one end near the process end.

[0008] A method for supplying low vapor pressure liquid gas comprises the following steps: 1) The liquid gas source enters the preheating box from the storage tank through the delivery pipeline. The preheating box heats the liquid gas to 3-5℃ below the boiling point of steam; 2) After preheating, the uniformly heated liquid gas is transported to the evaporation heating tank through the first electric heating and insulation pipeline, and is heated by electric heating to a temperature 10-15°C above the evaporation boiling point of the liquid gas; 3) The liquid gas in the evaporation heating tank is converted into gaseous state, and is transported to the process end through the second electric heating and insulation pipeline by detecting the pressure and mass flow of the delivery pipeline, and the instantaneous temperature change is monitored in real time.

[0009] The advantages of the present invention are as follows: the structure and method are reasonably designed, and the method of setting the preheating temperature and the evaporation heating temperature in sections is adopted to meet the thermodynamic and fluid calculations. Under the premise of ensuring that the liquid gas is heated evenly in two sections, the requirements of stable pressure and large flow supply are achieved with a stable evaporation temperature. There is no need to introduce argon or helium or other gases into the evaporation tank to increase the evaporation amount, and the corresponding process pipeline valves are omitted, which can effectively reduce the use cost and equipment energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic structural diagram of the low vapor pressure liquid gas supply device of the present invention.

[0011] In the figure, 1 is the conveying pipeline, 2 is the first pneumatic diaphragm valve, 3 is the first isolating valve, 4 is the preheating box, 5 is the second isolating valve, 6 is the first electric heating and insulation pipeline, 7 is the second pneumatic diaphragm valve, 8 is the third isolating valve, 9 is the evaporative heating tank, 10 is the fourth isolating valve, 11 is the pressure transmitter (PT), 12 is the third pneumatic diaphragm valve, 13 is the mass flow controller (MFC), 14 is the second electric heating and insulation pipeline, A is the storage tank, and B is the process end. DETAILED DESCRIPTION

[0012] The present invention is further described in detail below with reference to examples and specific implementation methods.

[0013] like Figure 1As shown, a low vapor pressure liquid gas supply device comprises a storage tank A, a preheating box 4, an evaporation heating tank 9 and a process end B, wherein the outlet of the storage tank A is connected to the inlet of the preheating box 4 through a conveying pipeline 1, the outlet of the preheating box 4 is connected to the inlet of the evaporation heating tank 9 through a first electric heating and insulation pipeline 6, and the outlet of the evaporation heating tank 9 is connected to the process end B through a second electric heating and insulation pipeline 14.

[0014] The preheating box 4 is preferably an induction heating box, that is, a liquid gas coil is arranged in the box, and an electromagnetic induction coil is arranged around the coil. The evaporation heating tank 9 is preferably an electric heating evaporation heating tank with a double shell, that is, the first electric heating and insulation pipe 6 and the second electric heating and insulation pipe 14 are respectively connected to the inner tank body, and an electric heater is arranged between the inner tank body and the outer tank body.

[0015] The inner side of the preheating box 4 and the inner side of the outer tank of the evaporation heating tank 9 are preferably made of quartz insulation material to keep warm and insulate to reduce thermal attenuation.

[0016] During the specific design, a first pneumatic diaphragm valve 2 is provided on the portion of the conveying pipeline 1 close to the storage tank A, a first isolation valve 3 is provided on the portion of the conveying pipeline 1 close to the preheating box 4, a second isolation valve 5, a second pneumatic diaphragm valve 7 and a third isolation valve 8 are provided in sequence on the first electric heating and insulation pipeline 6 from an end close to the preheating box to an end close to the evaporative heating tank 9, and a fourth isolation valve 10, a temperature sensor 11, a third pneumatic diaphragm valve 12 and a mass flow controller 13 are provided in sequence on the second electric heating and insulation pipeline 14 from an end close to the evaporative heating tank 9 to an end close to the process end B.

[0017] During operation, the liquid gas is heated by the secondary heating system to obtain a stable evaporation temperature and a pressure and flow rate that meet the process requirements. Specifically, the liquid gas source enters the preheating box 4 (the inner surface Ra of the box is less than 0.1µm, increasing heat radiation and improving thermal efficiency) from the storage tank A through the delivery pipe 1. The preheating box 4 heats the liquid gas to 3-5°C below the steam boiling point (such as SiCl4, the preheating temperature is set to 55°C). After preheating, the uniformly heated liquid gas is transported to the evaporation heating tank 9 through the first electric heating and insulation pipe 6, and then heated to 10-15°C above the evaporation boiling point of the liquid gas by electric heating (such as SiCl4, the evaporation heating temperature is 70°C). At this time, the liquid gas in the evaporation heating tank 9 is converted into a gaseous state, and finally through the second electric heating and insulation pipe 14, it is transported to the process end B (machine demand end) by detecting the pressure and mass flow of the delivery pipe, and the instantaneous temperature change is monitored in real time to ensure that the gas evaporation flow and pressure meet the process requirements.

[0018] The temperatures of the preheating box 4 and the evaporation heating tank 9 can be monitored and precisely controlled in real time in combination with the infrared temperature control system to ensure the evaporation pressure of the liquid gas and control the gas flow to be delivered to the machine to meet the needs of the process reaction. It is no longer necessary to introduce argon or helium and other gases into the evaporation tank to increase the evaporation amount, and the process pipeline valves for the supply of argon or helium can also be omitted, thereby reducing the use cost and equipment energy consumption.

[0019] Example: Supply of SiCl4 The boiling point of SiCl4 is 57.6°C and the saturated vapor pressure is 55.99 kPa.

[0020] SiCl4 liquid gas source enters the preheating box 4 from the storage tank A through the delivery pipeline 1. The preheating box 4 heats the liquid gas to 55°C. The preheated liquid gas is evenly heated through the first electric heating and insulation pipeline 6 to the evaporation heating tank 9, and then heated to 70°C by electric heating. At this time, the liquid gas in the evaporation heating tank 9 is converted into gaseous state, and finally delivered to the process end B through the second electric heating and insulation pipeline 14 by detecting the pressure and mass flow of the delivery pipeline.

[0021] All the components mentioned above are prior art, and those skilled in the art can use any model and existing design that can achieve their corresponding functions.

[0022] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A low vapor pressure liquid gas supply device, characterized in that: The invention comprises a storage tank (A), a preheating box (4), an evaporative heating tank (9) and a process end (B), wherein the outlet of the storage tank (A) is connected to the inlet of the preheating box (4) via a delivery pipeline (1), the outlet of the preheating box (4) is connected to the inlet of the evaporative heating tank (9) via a first electric heating and heat-insulating pipeline (6), and the outlet of the evaporative heating tank (9) is connected to the process end (B) via a second electric heating and heat-insulating pipeline (14).

2. A low vapor pressure liquid gas supply device as claimed in claim 1, characterized in that: The inner side of the preheating box (4) and the inner side of the evaporation heating tank (9) are both made of quartz insulation material.

3. A low vapor pressure liquid gas supply device as claimed in claim 1, characterized in that: The inner surface Ra of the preheating box (4) is less than 0.1 µm.

4. A low vapor pressure liquid gas supply device as claimed in claim 1, characterized in that: The portion of the delivery pipeline (1) close to the storage tank (A) is provided with a first pneumatic diaphragm valve (2), the portion of the delivery pipeline (1) close to the preheating box (4) is provided with a first isolation valve (3), the first electric heating and insulation pipeline (6) is provided with a second isolation valve (5), a second pneumatic diaphragm valve (7) and a third isolation valve (8) in sequence from the end close to the preheating box to the end close to the evaporation heating tank (9), and the second electric heating and insulation pipeline (14) is provided with a fourth isolation valve (10), a temperature sensor (11), a third pneumatic diaphragm valve (12) and a mass flow controller (13) in sequence from the end close to the evaporation heating tank (9) to the end close to the process end (B).

5. A supply method for a low vapor pressure liquid gas supply device as claimed in claim 1, characterized in that: The following steps are involved: 1) The liquid gas source enters the preheating box (4) from the storage tank (A) through the delivery pipeline (1), and the preheating box (4) heats the liquid gas to a temperature 3-5°C below the boiling point of steam; 2) The preheated and uniformly heated liquid gas is transported to the evaporation heating tank (9) through the first electric heating and insulation pipe (6), and is heated by electric heating to a temperature 10-15° C. above the evaporation boiling point of the liquid gas; 3) The liquid gas in the evaporation heating tank (9) is converted into gaseous state and transported to the process end (B) through the second electric heating and insulation pipeline (14) by detecting the pressure and mass flow of the transport pipeline, and the instantaneous temperature change is monitored in real time.

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