A pipeline chemical heater

Abstract

The present invention discloses a pipeline chemical heater, comprising an infrared heater, a liquid chemical pipeline outside the infrared heater, a quartz pipeline disposed inside the liquid chemical pipeline corresponding to the outer wall of the infrared heater, a gap disposed between the quartz pipeline wall and the infrared heater, the gap filled with a phase change material, a plurality of infrared heaters, and a plurality of quartz fins disposed inside the liquid chemical pipeline. The present invention adds a medium material capable of capturing and absorbing energy within a wide range of the infrared spectrum between the infrared heater and the liquid chemical pipeline to avoid wasting this energy. The dedicated medium material directly conducts heat to the chemical cavity, and the rate of heat conduction is higher than that of heat radiation. The present invention utilizes the phase change properties of the material to maintain a constant temperature, is unaffected by process fluctuations, and can prevent an increase in the corrosion rate of phosphoric acid due to local overheating.

Description

Technical Field

[0001] The present invention relates to the field of heaters, in particular to a pipeline chemical heater. Background Art

[0002] The semiconductor industry relies on a complex, meticulously controlled process to produce high-precision silicon and metal structures, commonly referred to as integrated circuits (ICs) or chips. Each step in the manufacturing process requires advanced equipment to monitor the conditions of the silicon wafers and numerous process gases and fluids. To achieve ideal manufacturing results, these process fluids must typically be maintained at a specified temperature, neither too high nor too low. Sometimes these fluids are toxic or corrosive, such as sulfuric acid, phosphoric acid, hydrochloric acid, and ammonia hydrate. To protect operators and equipment, the heating process must be controlled within a safe environment. Furthermore, the semiconductor industry consumes significant amounts of energy, with heating and cooling systems consuming the most. Global efforts to conserve energy and reduce emissions necessitate improvements in the efficiency of these processes.

[0003] The semiconductor industry has experienced numerous developments and advancements in methods for heating corrosive chemicals over the past few decades. Early designs used stainless steel or plastic containers, but the inherent corrosiveness of the chemicals and the high temperatures resulted in short system lifespans. Later designs employed containers made of glass or quartz, which are more corrosion-resistant, and quartz offers superior strength even at high temperatures. However, even quartz can be corroded or destroyed by high-temperature phosphoric acid (above 150°C), which typically needs to be maintained between 160-170°C in semiconductor industry processes. The latest designs utilize infrared (IR) heating systems, which transfer heat to the liquid between two quartz walls via radiation, without the corrosive liquid ever coming into contact with the heater. An air gap exists between the heater's protective quartz jacket and the chemical chamber's quartz walls, allowing any leaks in the chemical container to trigger the leak detector without damaging the heater. However, IR heating systems are inefficient, requiring extremely high-wattage heaters, sometimes up to three times the power required to heat the liquid. A significant amount of infrared energy is absorbed by the gap between the quartz and air, causing local temperatures to sometimes exceed 180°C. This exponentially increases the quartz corrosion rate when phosphoric acid is heated. Consider a case in which phosphoric acid is used in an etching process in wafer manufacturing. The phosphoric acid circulating between the etch chamber and the inline heater must be maintained at a specified 165°C. While the temperature controller maintains the chemical temperature as precisely as possible, placing a box of low-temperature wafers into the etch chamber causes the phosphoric acid temperature to drop significantly. The temperature controller then increases the heating power, and the quartz wall absorbs significant infrared radiation, causing its temperature to exceed 180°C. The localized temperature of the phosphoric acid near the quartz wall also exceeds 180°C. This causes the quartz corrosion rate to exceed the initial design estimate. This not only wastes a significant amount of heat but also shortens the life of the chemical chamber. Summary of the Invention

[0004] In order to solve the above technical problems, the technical solution provided by the present invention is: a pipeline chemical heater, including an infrared heater, a liquid chemical pipeline outside the infrared heater, a quartz pipeline corresponding to the outer wall of the infrared heater is arranged in the liquid chemical pipeline, a gap is set between the quartz pipeline wall and the infrared heater, the gap is filled with phase change material, the number of the infrared heaters is multiple, and several quartz fins are arranged in the liquid chemical pipeline.

[0005] Furthermore, the phase change point of the phase change material is between 160-175°C.

[0006] Furthermore, the number of the infrared heaters is five, and they are evenly distributed in the liquid chemical pipeline.

[0007] Furthermore, the quartz fins include transverse heating fins arranged outside the infrared heater and oblique heating fins arranged at the four corners of the liquid chemical pipeline.

[0008] Furthermore, a liquid inlet pipe is provided at one end of the liquid chemical pipeline, and a liquid outlet pipe is provided at the other end.

[0009] The advantages of the present invention compared with the prior art are:

[0010] (1) The present invention adds a medium material between the infrared heater and the liquid chemical pipeline that can capture and absorb energy within a wide range of the infrared spectrum to avoid wasting this energy.

[0011] (2) The present invention directly conducts heat to the chemical cavity through a dedicated medium material, and the rate of heat conduction is higher than that of heat radiation.

[0012] (3) The phase change material selected in the present invention has a phase change point between 160-175°C to cope with the target operating temperature of phosphoric acid in the semiconductor etching process.

[0013] (4) The present invention utilizes the phase change properties of the material to maintain a constant temperature, which is not affected by process fluctuations and can prevent the increase in the corrosion rate of phosphoric acid caused by local overheating.

[0014] (5) When heating other chemicals with lower temperatures than phosphoric acid, the phase change medium remains solid and conducts heat at a higher rate than heat transfer through an air interlayer.

[0015] (6) The internal structure of the quartz chemical chamber is optimized by setting quartz fins to enhance the turbulent effect and enhance the convection heat transfer. By balancing and optimizing the three heat transfer methods of heat conduction, heat convection and heat radiation, the total amount of heat exchange is maximized, energy waste is minimized and heat transfer efficiency is increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the internal structure of a pipeline chemical heater of the present invention.

[0017] Figure 2 It is a schematic diagram of the internal structure of a pipeline chemical heater of the present invention.

[0018] Figure 3 It is a schematic diagram of the cross-sectional structure of a pipeline chemical heater of the present invention. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0020] In the description of the embodiments of the present invention, it should be noted that if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the product of the invention is usually placed when in use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it should not be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0021] Furthermore, the use of terms such as "horizontal," "vertical," and "overhanging" does not necessarily imply that the component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," not that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0022] In the description of the embodiments of the present invention, "a plurality of" means at least two.

[0023] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0024] Example:

[0025] Combined with attachment Figure 1-3A pipeline chemical heater includes an infrared heater 1, a liquid chemical pipeline 2 outside the infrared heater 1, a quartz pipeline 3 corresponding to the outer wall of the infrared heater 1 is arranged in the liquid chemical pipeline 2, a gap 4 is arranged between the wall of the quartz pipeline 3 and the infrared heater 1, and the gap 4 is filled with a phase change material. The phase change point of the phase change material is between 160-175°C. There are multiple infrared heaters 1. In this embodiment, the number of infrared heaters 1 is five, which are evenly distributed in the liquid chemical pipeline 2; a plurality of quartz fins 5 are arranged in the liquid chemical pipeline 2, and the quartz fins 5 include horizontal heating fins 501 arranged outside the infrared heater 1 and oblique heating fins 502 arranged at the four corners of the liquid chemical pipeline 1; a liquid inlet pipe 6 is arranged at one end of the liquid chemical pipeline 2, and a liquid outlet pipe 7 is arranged at the other end.

[0026] This embodiment considers system design from a new perspective, rather than seeking the highest power heater. In order to maximize the amount of chemical that can be heated, the goal of this embodiment is to optimize the heat exchange process. If a higher proportion of heat can be transferred efficiently and less energy is wasted in the form of heat, the size of the heater will also be smaller, and this will also have a positive effect on cost savings and environmental protection. Although infrared heating has the advantage of heating the chemical without direct contact with the heater, the chemical may only absorb a small portion of the energy from the infrared spectrum. Quartz also absorbs infrared radiation from different regions of the spectrum, but the energy in the main range of the infrared spectrum is not directly absorbed by quartz, resulting in this part of the infrared energy being wasted. This design adds a medium to the air layer on the outer wall of the quartz between the infrared heater and the liquid chemical pipeline.

[0027] This phase-change medium is transparent to the infrared region of the spectrum, allowing some infrared energy to pass through it and be absorbed by the chemical. However, this material absorbs energy from other regions of the infrared spectrum that would otherwise be wasted. This material can then conduct heat to the chemical through the quartz wall. Furthermore, this specialized material has a phase transition point of 160-175°C, melting from a solid (below 160°C) to a liquid (above 170°C). Maintaining the material temperature near its phase transition point allows for simpler system temperature control without directly adjusting the chemical temperature. In the aforementioned scenario, phosphoric acid circulates through the etching chamber and heater used to process wafers, maintaining a temperature of 170-175°C. A box of low-temperature silicon wafers is placed in the etching chamber, causing the phosphoric acid to cool. However, the specialized phase-change material begins to solidify, transferring heat to the chemical without changing its temperature. Once fully solidified, its temperature drops, triggering a temperature controller to increase the heating power. Some of this increased infrared energy is transferred to the acid solution, but most is absorbed by the phase-change material. Subsequently, when the phase-change material melts and the temperature rises to 175°C, the temperature controller reduces the heating power. Throughout this process, the phosphoric acid never exceeds 180°C, allowing for more precise control of the quartz etching rate, less heat waste, and a longer heater life. For chemicals at lower temperatures, heat can be directly transferred to the chemical itself through the solid medium material, which is more efficient than the air sandwich design.

[0028] To further improve heat exchange efficiency, quartz fins are installed inside the liquid chemical pipeline, which can be optimized to create turbulent internal fluid flow. Turbulence enhances mixing and increases the heat exchange rate. The quartz structure inside the container is designed for multi-channel flow, and several heat pipes are added to ensure uniform heat distribution throughout the system. Although the system is primarily designed to minimize phosphoric acid corrosion, the quartz structure and infrared heaters are both independently replaceable, which can reduce the total cost of system maintenance over the years. By optimizing the three modes of heat transfer: heat radiation, heat conduction, and heat convection, the system's overall energy consumption is lower.

[0029] The present invention and its embodiments are described above. This description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without inventiveness, they shall fall within the scope of protection of the present invention.

Claims

1. A pipeline chemical heater, characterized in that: The device comprises an infrared heater, a liquid chemical pipeline outside the infrared heater, a quartz pipeline corresponding to the outer wall of the infrared heater arranged in the liquid chemical pipeline, a gap arranged between the quartz pipeline wall and the infrared heater, the gap being filled with a phase change material, a plurality of infrared heaters, and a plurality of quartz fins arranged in the liquid chemical pipeline; the phase change point of the phase change material is between 160-175°C; the quartz fins include horizontal heating fins arranged outside the infrared heater and oblique heating fins arranged at the four corners of the liquid chemical pipeline.

2. A pipeline chemical heater according to claim 1, characterized in that: The number of the infrared heaters is five and they are evenly distributed in the liquid chemical pipeline.

3. A pipeline chemical heater according to claim 1, characterized in that: A liquid inlet pipe is arranged at one end of the liquid chemical pipeline, and a liquid outlet pipe is arranged at the other end.

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