IPA instantaneous heater

Abstract

The invention discloses an IPA instantaneous heater in the field of semiconductor equipment, which comprises a shell, a heating core and a heating pipeline positioned in the shell, a closed accommodating cavity is formed in the shell, the heating core performs heat conduction heating on an IPA medium in the pipeline, and the shell is provided with an air inlet and an air outlet. The containing cavity is filled with inert protective gas which is positive pressure relative to the external air pressure. The heater carries out secondary heating at the outlet end of the device, the risk that a large amount of high-temperature IPA is detained in a long pipeline is avoided, and a safe and reliable semiconductor cleaning and drying process heating solution is provided in the mode that outlet end heating is matched with inert gas protection.

Description

Technical Field

[0001] This invention relates to the field of semiconductor equipment, and more specifically to an IPA instantaneous heater. Background Technology

[0002] In the semiconductor manufacturing industry, the cleaning process is a critical step in ensuring the performance, stability, and high yield of semiconductor devices. The temperature stability of the chemical solutions during cleaning is crucial for ensuring the uniformity of the reaction between the wafer and the chemical solutions. Especially in advanced processes, after cleaning, isopropanol (IPA) and other chemicals are used to replace water on the wafer surface for drying; the temperature accuracy of these solutions significantly impacts the final drying effect.

[0003] In existing technologies, circulating online heating is typically used at the liquid supply end to increase the temperature of the IPA medium. However, when the IPA medium is transported from the liquid supply end to the equipment end, the medium dissipates heat in the pipeline due to its long length. This results in a significant difference between the actual temperature of the medium at the machine outlet and the target temperature set at the liquid supply end, making it difficult for the outlet temperature to consistently reach the expected target temperature. This significantly reduces the cleaning and drying effect.

[0004] To compensate for the temperature difference caused by heat dissipation from the pipeline, an intuitive solution is to increase the medium heating temperature set at the liquid supply end, so that the sum of the liquid supply temperature and the heat lost from the pipeline is exactly equal to the final target temperature required by the medium.

[0005] However, IPA media is inherently flammable and explosive. Setting the heating temperature too high would cause a large amount of IPA media to remain at a high temperature throughout the delivery pipeline for an extended period. This significantly increases the safety risks of the entire system, especially in cases of pipeline leaks or static electricity buildup, potentially leading to serious safety accidents.

[0006] Therefore, the existing circulating online heating method and the strategy of simply and crudely increasing the supply liquid temperature are not suitable for IPA media with extremely high safety requirements.

[0007] In summary, there is a pressing technical problem in the existing technology: how to accurately and reliably raise the temperature of the IPA medium to the target value while ensuring safety, so as to guarantee the effectiveness of the semiconductor cleaning and drying process. Summary of the Invention

[0008] The purpose of this invention is to provide an IPA instantaneous heater to solve the problems of substandard outlet temperature caused by heat dissipation during the transportation of flammable and explosive IPA media, as well as the safety hazards of existing solutions for increasing the supply temperature.

[0009] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution: An IPA instantaneous heater, characterized in that it comprises: The outer shell contains a sealed cavity. The heating element is fixedly installed inside the receiving cavity; The heating pipe is located inside the cavity and is in contact with the heating core. The heating pipe has an inlet and an outlet, both of which are connected to the side wall of the outer shell. The heating core heats the medium flowing through the heating pipe by means of heat conduction. The outer shell is provided with an air inlet and an air outlet. The cavity is filled with inert protective gas that enters through the air inlet and flows out through the air outlet. The inert protective gas in the cavity is set to be in a positive pressure state relative to the external air pressure.

[0010] Furthermore, the heating core consists of a heat transfer core and several heating rods embedded in the heat transfer core. The axial direction of all heating rods is parallel to the axial direction of the heat transfer core, and all heating rods are evenly distributed circumferentially about the heat transfer core.

[0011] Furthermore, a non-closed spiral groove is formed on the outer wall of the heat transfer core, and the non-closed side of the spiral groove intersects with the outer wall of the heat transfer core. The heating pipe is a spiral tube, which is embedded in a spiral groove, and the groove wall is in contact with the outer wall of the spiral tube.

[0012] Furthermore, a helical spring strip is embedded in the opening of the helical groove. The helical spring strip covers the helical tube inside the helical groove, and the inner side of the helical spring strip contacts the helical tube and is exposed on the outer wall of the opening of the helical groove.

[0013] Furthermore, the outer wall of the helical spring strip is flush with the cylindrical outer wall of the heat transfer core, and an insulation shell that is in close contact with the outer wall is fitted around the outside of the heat transfer core. The liquid inlet and outlet penetrate the insulation shell outwards.

[0014] Furthermore, the heat transfer core has several through holes extending along its axial direction to reduce the thermal inertia of the heat transfer core. The through holes are evenly distributed along the circumference of the heat transfer core.

[0015] Furthermore, thermocouples are provided at the liquid inlet, liquid outlet, and heat transfer core, with the thermocouples on the heat transfer core being embedded and close to the heating rod.

[0016] Furthermore, the air outlet is equipped with a back pressure valve to create a positive pressure effect.

[0017] Furthermore, the outer casing is provided with a through-plate connector for leading out the electrode wiring of the heating rod, the through-plate connector being used to keep the receiving cavity sealed.

[0018] Furthermore, the outer shell is made of SUS304 material, and a protective shell made of PTFE material is also wrapped around the outside of the outer shell.

[0019] The beneficial effects of this invention are: The heater of this invention is installed at the outlet end of the equipment to heat the IPA medium to be used, thereby effectively solving the problem in the prior art that the supply liquid temperature must be increased due to pipeline heat dissipation. This avoids the safety hazards of high temperature, flammable and explosive IPA medium remaining in long-distance pipelines for a long time, and achieves a balance between safety and process precision. At the same time, positive pressure inert protective gas is introduced to achieve the inertization protection effect on the heating element. Attached Figure Description

[0020] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0021] Figure 1 This is a longitudinal sectional view of an embodiment of the present invention; Figure 2 This is a cross-sectional view of an embodiment of the present invention; Figure 3 for Figure 1 Enlarged schematic diagram of the structure at point A in the diagram; Figure 4 This is a schematic diagram of the external structure of an embodiment of the present invention; Figure 5 This is the outlet temperature profile of a conventional IPA heater; Figure 6 This is a graph showing the outlet temperature of the improved IPA heater according to the present invention. Figure 7 Temperature profile of the heat transfer core of a conventional IPA heater; Figure 8 The temperature curve of the heat transfer core of the IPA heater after the improvement of this invention; The labels in the diagram represent the following: 1-outer shell; 1a-air inlet; 1b-air outlet; 2-heating pipe; 2a-liquid inlet; 2b-liquid outlet; 3-heat transfer core; 4-heating rod; 5-spiral spring strip; 6-insulation shell; 7-perforated through hole; 8-protective shell; 9-through plate connector. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] To address the issues of temperature instability caused by heat dissipation from pipelines during IPA medium delivery to the equipment, and the serious safety hazards associated with increasing the supply temperature in existing technologies, this embodiment provides an IPA instantaneous heater. This heater is installed at the liquid consumption point on the equipment side to instantly heat the IPA medium, thereby precisely controlling the outlet temperature while ensuring process safety.

[0024] Specifically, refer to Figures 1 to 4 The IPA instantaneous heater includes: An outer shell 1, which forms a sealed receiving cavity; A heating element is fixedly installed inside the receiving cavity; A heating pipe 2 is located inside the receiving cavity and is in contact with the heating core. The heating pipe 2 has a liquid inlet 2a and a liquid outlet 2b, both of which are connected to the side wall of the outer casing 1.

[0025] During operation, the low-temperature IPA medium flows in from the inlet 2a and, as it flows through the heating pipe 2, the heating core heats the medium flowing through the heating pipe 2 by means of heat conduction. The high-temperature IPA medium flows out from the outlet 2b and is directly supplied to the equipment.

[0026] To address the safety concerns posed by the flammability and explosiveness of IPA, this heater incorporates special safety design considerations. Specifically, an air inlet 1a and an air outlet 1b are provided on the outer casing 1. The containment cavity is filled with an inert protective gas (such as nitrogen) that enters through the air inlet 1a and flows out through the air outlet 1b. By controlling the inlet and outlet of the gas, the inert protective gas in the containment cavity is set to a positive pressure state relative to the external air pressure.

[0027] The technical advantage of this design is that both the heating pipe 2 and the heating core are enclosed in a positive pressure inert gas environment. In the event of a leak in the heating pipe 2, the flammable IPA medium will leak into the oxygen-free inert gas environment, preventing combustion or explosion.

[0028] At the same time, because the interior is under positive pressure, the inert gas inside the cavity will leak outwards, while outside air (oxygen) cannot enter the cavity, thus providing a very high level of safety.

[0029] In the above scheme, the heating core is the key component for achieving heat supply. To ensure that the heating core can generate and transfer heat stably and uniformly, this embodiment provides a preferred structure in which the heating core consists of a heat transfer core 3 and several heating rods 4 embedded within the heat transfer core 3. The heat transfer core 3 can be made of aluminum alloy, for example, which has good thermal conductivity. The axial direction of all heating rods 4 is parallel to the axial direction of the heat transfer core 3, and all heating rods 4 are uniformly distributed circumferentially with respect to the heat transfer core 3. The heating rods 4 (e.g., electric heating rods) are the source of heat. By uniformly embedding the heating rods 4 into the heat transfer core 3, which has high thermal conductivity such as aluminum alloy, heat can be rapidly and uniformly transferred to the entire heat transfer core 3, avoiding localized overheating and providing a uniform and stable heating surface for the heating pipe 2.

[0030] Furthermore, in order to efficiently transfer the heat from the heat transfer core 3 to the IPA medium flowing through the heating pipe 2, simply attaching the pipe to the surface of the heat transfer core 3 would result in limited contact area, low heat transfer efficiency, and difficulty in achieving an "instantaneous heating" effect. To maximize heat transfer efficiency, a non-closed spiral groove is formed on the outer wall of the heat transfer core 3, with the non-closed side of the spiral groove intersecting with the outer wall of the heat transfer core 3. Correspondingly, the heating pipe 2 is a spiral tube, which is embedded in the spiral groove.

[0031] In this way, the heating pipe 2 is spirally wound around the heat transfer core 3, which greatly increases the flow path length of the medium in the heating zone. At the same time, the spiral tube is embedded in the spiral groove, so that the groove wall of the spiral groove and the outer wall of the spiral tube can be in contact with each other over a large area. This significantly improves the heat transfer area and heat transfer efficiency, so that the medium can be heated to the target temperature in a short time.

[0032] Although the helical tube is embedded in the helical groove, tolerances may exist during manufacturing and assembly, or minute gaps may form between the helical tube and the groove wall after the equipment undergoes thermal expansion and contraction cycles. These gaps can significantly hinder heat conduction, reducing heating efficiency and stability. To ensure a tight contact between the two at all times, a helical spring strip 5 is embedded at the opening of the helical groove. The helical spring strip 5 encloses the helical tube within the helical groove, with its inner side contacting the helical tube exposed on the outer wall of the opening of the helical groove. Utilizing its own elasticity, the helical spring strip 5 continuously presses the helical tube against the inner wall of the helical groove, thereby eliminating potential gaps and ensuring efficient and stable heat conduction between the heat transfer core 3 and the heating pipe 2.

[0033] To further reduce energy loss, the heat transfer core 3, being at a high temperature, radiates heat to the inert gas within the containment cavity and the outer shell 1, resulting in energy waste and potentially causing the outer shell 1 to overheat. Therefore, the outer wall of the helical spring strip 5 is flush with the cylindrical outer wall of the heat transfer core 3, forming a regular cylindrical shape with the heat transfer core 3, the helical tube, and the helical spring strip 5. Then, an insulation shell 6, in close contact with the outer wall, is fitted over the heat transfer core 3, with the liquid inlet 2a and outlet 2b extending outwards through the insulation shell 6. This insulation shell 6 (e.g., made of insulating material) effectively blocks heat diffusion from the heat transfer core 3, concentrating heat in the heating pipe 2 area, improving the heater's thermal efficiency, and reducing energy consumption.

[0034] For semiconductor processes, not only is stable heating required, but the heating system also needs to have a rapid response capability to cope with rapid changes in process conditions. While the solid heat transfer core 3, made of materials such as aluminum alloy, has good thermal stability, its thermal inertia is also relatively large, resulting in a slower rate of heating and cooling.

[0035] To maintain thermal uniformity while reducing thermal inertia, several through holes 7 are formed on the heat transfer core 3, extending along its axial direction. These through holes 7 are evenly distributed around the circumference of the heat transfer core 3. These through holes reduce the overall mass of the heat transfer core 3, thereby significantly reducing thermal inertia. This allows the heating core to heat up and cool down more quickly, improving the heater's response speed to changes in the temperature setpoint.

[0036] To achieve precise control of the outlet medium temperature, real-time monitoring and closed-loop control of the heating process are necessary. Therefore, thermocouples are installed at the inlet 2a, outlet 2b, and heat transfer core 3. The thermocouples on the heat transfer core 3 are embedded and located close to the heating rod 4. The thermocouple at the inlet 2a monitors the temperature of the incoming medium, while the thermocouple at the outlet 2b monitors the final medium temperature, serving as the primary feedback signal for control. The thermocouple embedded in the heat transfer core 3 (close to the heating rod 4) monitors the temperature of the heating source and provides a rapid feedforward signal, which is more accurate than the temperature detected from the surface of the heat transfer core 3.

[0037] These thermocouple signals are transmitted to an external controller that uses PID temperature control to precisely control the medium temperature at the outlet 2b by adjusting the power of the heating rod 4, so that it is stabilized at the target value required by the process.

[0038] In terms of safety design, as mentioned above, the containment cavity needs to maintain a stable positive pressure state. In order to reliably achieve this function, a back pressure valve is installed at the outlet 1b to create a positive pressure effect. Inert gas is continuously introduced from the inlet 1a, while the back pressure valve ensures that the gas is discharged only when the pressure in the containment cavity exceeds a set value (for example, slightly higher than the external atmospheric pressure). This ensures that the containment cavity always maintains a stable positive pressure state and prevents the intrusion of outside air.

[0039] The heating rod 4 inside the heating core and the thermocouple on the heat transfer core 3 both require wires to be led out of the housing 1 to connect to the power supply and controller. These wires must pass through the sealed cavity wall. In order to maintain the airtightness of the cavity while leading out the wires, a through-plate connector 9 is provided on the housing 1 for leading out the electrode wires of the heating rod 4. This through-plate connector 9 (or other type of sealed connector) is used to keep the cavity sealed, which ensures the reliability of the electrical connection and maintains the integrity of the positive pressure inert gas environment inside the cavity.

[0040] Considering the potential presence of corrosive gases in semiconductor manufacturing environments, the durability of the equipment housing 1 is crucial. In this embodiment, the housing 1 can be made of SUS304 stainless steel, which possesses good mechanical strength and basic corrosion resistance. To further enhance its protection in harsh environments, a PTFE (polytetrafluoroethylene) protective shell 8 is also added to the outside of the housing 1. PTFE has excellent chemical corrosion resistance, and when used over the SUS304 housing 1, it effectively resists the erosion of corrosive gases, extending the heater's service life.

[0041] Finally, see Figure 5 and Figure 6 The diagram shows a comparison of the outlet temperature curves of the existing heater (solid heat transfer core) and the heater of the present invention (hollow heat transfer core). The data curves show that the temperature fluctuation range of the IPA heater design is 71.5-72.4℃, with a fluctuation amplitude of 0.9℃. The improved design has a temperature range of 71.7-72.2℃, with the fluctuation amplitude significantly reduced to 0.5℃. This improvement directly solves the problem of insufficient temperature control accuracy in the existing heater, reducing the temperature fluctuation range by approximately 44.4%. This greatly improves the process stability, control accuracy, and product yield of the heater in applications involving temperature-sensitive fluids (such as IPA).

[0042] See Figure 7 and Figure 8The diagram shows a comparison of the heat transfer core temperature curves of a prior art heater (with the thermocouple attached to the surface of the heat transfer core) and a heater of the present invention (with the thermocouple inserted inside the heat transfer core, near the heating rod). The curves show that the temperature fluctuation range of the heat transfer core in the prior art is 83.5-84.5℃, while the temperature range of the improved heat transfer core in this invention is 81.5-82℃. The overall temperature of the heat transfer core is lower, and for organic solvents like IPA media, temperatures lower than the boiling point of IPA are safer.

[0043] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered as falling within the scope of protection of the embodiments of the present invention.

Claims

1. An IPA flash heater characterized in that, include: The outer shell (1) has a sealed cavity inside; The heating element is fixedly disposed within the receiving cavity; A heating pipe (2) is located inside the receiving cavity and is in contact with the heating core. The heating pipe (2) has an inlet (2a) and an outlet (2b). The inlet (2a) and the outlet (2b) are both connected to the side wall of the outer shell (1). The heating core heats the medium flowing through the heating pipe (2) by means of heat conduction. The outer shell (1) is provided with an air inlet (1a) and an air outlet (1b). The cavity is filled with an inert protective gas that enters through the air inlet (1a) and flows out through the air outlet (1b). The inert protective gas in the cavity is set to be in a positive pressure state relative to the external air pressure.

2. An IPA flash heater according to claim 1, wherein The heating core consists of a heat transfer core (3) and a number of heating rods (4) embedded in the heat transfer core (3). The axial direction of all the heating rods (4) is parallel to the axial direction of the heat transfer core (3), and all the heating rods (4) are evenly distributed around the heat transfer core (3).

3. An IPA flash heater according to claim 2, wherein A non-closed spiral groove is formed on the outer wall of the heat transfer core (3), and the non-closed side of the spiral groove intersects with the outer wall of the heat transfer core (3). The heating pipe (2) is a spiral pipe, which is embedded in the spiral groove, and the groove wall of the spiral groove is in contact with the outer wall of the spiral pipe.

4. An IPA flash heater according to claim 3, wherein A helical spring strip (5) is embedded in the opening of the helical groove. The helical spring strip (5) covers the helical tube in the helical groove, and the inner side of the helical spring strip (5) contacts the helical tube and is exposed on the outer wall of the opening of the helical groove.

5. An IPA flash heater according to claim 4, wherein The outer wall of the helical spring strip (5) is flush with the cylindrical outer wall of the heat transfer core (3). A heat insulation shell (6) is fitted on the outer side of the heat transfer core (3) and is in close contact with the outer wall. The liquid inlet (2a) and the liquid outlet (2b) penetrate the heat insulation shell (6) outward.

6. An IPA flash heater according to claim 2, wherein The heat transfer core (3) has a plurality of through holes (7) extending along its axial direction to reduce the thermal inertia of the heat transfer core (3). The through holes (7) are evenly distributed along the circumference of the heat transfer core (3).

7. An IPA flash heater according to claim 2, wherein The inlet (2a), the outlet (2b), and the heat transfer core (3) are all equipped with thermocouples, wherein the thermocouples on the heat transfer core (3) are embedded and close to the heating rod (4).

8. An IPA flash heater according to claim 1, wherein The air outlet (1b) is equipped with a back pressure valve for creating the positive pressure effect.

9. An IPA flash heater according to claim 7, wherein The outer casing (1) is provided with a through-plate connector (9) for the electrode wiring of the heating rod (4) to be led out, and the through-plate connector (9) is used to keep the receiving cavity sealed.

10. An IPA flash heater according to claim 1, wherein The outer shell (1) is made of SUS304 material, and a protective shell (8) made of PTFE material is also wrapped around the outside of the outer shell (1).

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