Solid precursor conveying system for ALD (atomic layer deposition) process

Abstract

The invention discloses a solid precursor conveying system for an ALD (atomic layer deposition) process, and relates to the technical field of semiconductors. The device comprises a solid precursor source bottle, a steam conveying pipeline, a pneumatic valve and a reaction chamber, and further comprises a heating assembly, and the heating assembly comprises an air inlet heater, a source bottle heater, an air outlet heater of an air outlet, a steam conveying pipeline heater, a valve heater of the pneumatic valve and a reaction chamber top heater of a spray header. And the heating temperatures of the air inlet heater, the source bottle heater, the air outlet heater, the steam conveying pipeline heater, the valve heater and the reaction chamber heater are gradually increased. According to the method, stable and uniform solid precursor steam input is provided for the ALD process by adopting a step-by-step heating method and adopting a relatively low heating temperature in the early stage, so that the problem of low steam pressure of the solid precursor is effectively solved, the transportation rate is improved, uniform saturated adsorption is realized, stable sublimation of a solid precursor source is also realized, and the stability and reliability of the system are improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a solid-state precursor delivery system for ALD processes. Background Technology

[0002] With the continuous development of semiconductor technology, the requirements for material systems are becoming increasingly stringent. Many functional materials with cutting-edge application prospects are best suited for solid-state precursors. The application of solid-state precursors in the semiconductor field essentially fills the material gaps that liquid precursors cannot cover. For example, rare earth oxides are used in high-k gate dielectrics, memory, fluorescent materials, and catalysts; chalcogenides are important semiconductor, optoelectronic, and lubricating materials; and noble metals are used in electrodes, catalysts, and interconnect materials. However, the application of existing solid-state precursors in ALD processes faces the following challenges: 1. Solid materials need to be directly sublimated from the solid phase to the gas phase. The vapor pressure is usually low and the transport rate is slow. It requires a longer pulse time to reach surface saturation adsorption, resulting in a longer growth cycle and low production efficiency.

[0003] 2. Poor reproducibility of the transport process: Surface area changes lead to inconsistent precursor flux delivered to the cavity between different cycles and different batches. Due to the instability of transport flux, it is difficult to ensure that all areas of the substrate (especially large-area substrates) receive the exact same dose of precursor in each cycle, resulting in a growth rate lower than the theoretical value, uneven film thickness, and poor step coverage (three-dimensional structure coverage ability).

[0004] 3. Solid precursors are extremely sensitive to temperature. Condensation at "cold spots" may clog gas pipelines, valves, and cavity inlets, leading to equipment failure and process interruption. Decomposition at "hot spots" may cause pre-decomposition of the precursor during transport or before it reaches the substrate surface, undermining the self-limiting property of ALD and affecting the overall performance and application effect of the ALD process. Summary of the Invention

[0005] In view of this, the present invention aims to provide a solid precursor delivery system for ALD process to at least partially solve the problems of unstable transport, temperature sensitivity and difficulty in achieving uniform saturated adsorption of solid precursors in ALD process in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A solid precursor delivery system for ALD (Alternating Current Discharge) process includes a solid precursor source bottle, a vapor delivery pipeline, a pneumatic valve, and a reaction chamber. The solid precursor source bottle has a carrier gas inlet and a vapor outlet on its top sides, respectively. The vapor outlet is connected to the inlet end of the vapor delivery pipeline. The inlet end of the pneumatic valve is connected to the outlet end of the vapor delivery pipeline. The reaction chamber is connected to the outlet end of the pneumatic valve. The system also includes a heating assembly comprising an inlet heater at the inlet, a source bottle heater on the solid precursor source bottle, an outlet heater at the outlet, a vapor delivery pipeline heater, a valve heater for the pneumatic valve, and a reaction chamber top heater for the spray head. The heating temperatures of the inlet heater, source bottle heater, outlet heater, vapor delivery pipeline heater, valve heater, and reaction chamber heater increase progressively.

[0007] The beneficial effects achievable by this invention are as follows: By using a step-by-step heating method with a relatively low initial heating temperature, this invention provides a stable and uniform solid precursor vapor input for the ALD process, effectively solving the problem of low solid precursor vapor pressure, improving the transport rate, and enabling each cycle to reach surface saturation adsorption in a shorter time, significantly shortening the growth cycle, significantly improving production efficiency, and achieving stable sublimation of the solid precursor source, avoiding condensation and thermal decomposition problems caused by uneven temperature, thus improving the stability and reliability of the system.

[0008] Preferably, the heating temperature of the air inlet heater is 100-160℃; the heating temperature of the air outlet heater is 120-180℃; the heating temperature of the steam conveying pipeline heater is 130-190℃; the heating temperature of the valve heater is 135-200℃; and the heating temperature of the reaction chamber heater is 140-210℃.

[0009] Preferably, the inlet heater, the source bottle heater, the outlet heater, the steam delivery pipeline heater, the valve heater, and the reaction chamber heater are each electrically connected to a temperature sensor.

[0010] Preferably, each of the temperature sensors is electrically connected to a temperature controller.

[0011] Preferably, it also includes a central controller, which is electrically connected to each of the thermostats and each of the temperature sensors.

[0012] Preferably, the inlet heater, source bottle heater, outlet heater, steam delivery pipeline heater, valve heater, and reaction chamber top heater are all equipped with heating insulation sleeves, which include insulation cotton and heating elements embedded in the insulation cotton.

[0013] Preferably, the reaction chamber heater is located at the feed end of the spray head inside the reaction chamber.

[0014] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a solid precursor delivery system for ALD process, which has the following beneficial effects: 1. By using a stepwise heating method and a lower initial heating temperature, a stable and uniform solid precursor vapor input is provided for the ALD process, which effectively solves the problem of low solid precursor vapor pressure, improves the transport rate, and allows each cycle to reach surface saturation adsorption in a shorter time, greatly shortening the growth cycle and significantly improving production efficiency. 2. The heating system of the present invention achieves stable sublimation of solid precursor sources by precisely controlling the heating temperature of each component and using a step-by-step heating method, avoiding condensation problems caused by uneven temperature, ensuring the unobstructed flow of gas pipelines, valves and cavity inlets, avoiding the risk of equipment failure and process interruption, and improving the continuity and stability of production.

[0015] 3. The heating system of the present invention solves the problem of pre-decomposition that may be caused by excessively high temperatures by precisely controlling the heating temperature of each component and using a step-by-step heating method. This effectively improves the stability and reliability of the system, effectively maintains the self-limiting nature of the ALD process, and ensures high-quality film growth. 4. With the heating component of the present invention, the transport flux of the solid precursor becomes stable and controllable, ensuring that each region of the substrate receives the same dose of precursor in each cycle, which significantly improves the uniformity and thickness consistency of the film and solves the problems of uneven film thickness and low step coverage in the prior art. Attached Figure Description To more clearly illustrate the technical solutions in the embodiments of the present invention or 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 only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0016] Figure 1 This invention provides a schematic diagram of a solid precursor delivery system for ALD processes.

[0017] In the diagram: 1. Carrier gas inlet, 2. Solid precursor source bottle, 3. Vapor outlet, 4. Vapor delivery pipeline, 5. Pneumatic valve, 6. Reaction chamber, 10. Inlet heater, 20. Source bottle heater, 30. Outlet heater, 40. Vapor delivery pipeline heater, 50. Valve heater, 60. Reaction chamber heater. Detailed Implementation

[0018] 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.

[0019] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0020] Please see Figure 1 This invention discloses a solid precursor delivery system for ALD (Alternating Current Discharge) processes, comprising a solid precursor source bottle 2, a vapor delivery pipeline 4, a pneumatic valve 5, and a reaction chamber 6. The solid precursor source bottle has a carrier gas inlet 1 and a vapor outlet 3 on its top sides, respectively. The vapor outlet 3 is connected to the inlet end of the vapor delivery pipeline 4. The inlet end of the pneumatic valve 5 is connected to the outlet end of the vapor delivery pipeline 4. The reaction chamber 6 is connected to the outlet end of the pneumatic valve 5. The system also includes a heating assembly. The heating assembly includes an inlet heater 10 installed at the carrier gas inlet 1, a source bottle heater 20 on the solid precursor source bottle 2, an outlet heater 30 at the vapor outlet 3, a vapor delivery pipeline heater 40 on the vapor delivery pipeline 4, a valve heater 50 on the pneumatic valve 5, and a reaction chamber heater 60 at the top of the reaction chamber 6. The heating temperatures of the inlet heater 10, the source bottle heater 20, the outlet heater 30, the vapor delivery pipeline heater 40, the valve heater 50, and the reaction chamber heater 60 increase progressively.

[0021] The heating temperature of the inlet heater 10 is 100-160℃; the heating temperature of the outlet heater 30 is 120-180℃; the heating temperature of the steam conveying pipeline heater is 130-190℃; the heating temperature of the valve heater is 135-200℃; and the heating temperature of the reaction chamber heater 60 is 140-210℃.

[0022] The inlet heater 10, the source bottle heater 20, the outlet heater 30, the steam delivery pipeline heater 40, the valve heater 50, and the reaction chamber heater 60 are each electrically connected to a temperature sensor.

[0023] Each temperature sensor is electrically connected to a temperature controller.

[0024] It also includes a central controller, which is electrically connected to each thermostat and each temperature sensor.

[0025] The inlet heater 10, source bottle heater 20, outlet heater 30, steam delivery pipeline heater 40, valve heater 50, and reaction chamber heater 60 all adopt an integrated heating and insulation jacket. The heating and insulation jacket includes insulation cotton covering the outer wall of the corresponding equipment and heating elements embedded in the insulation cotton. In some other embodiments, the heating elements and insulation cotton are separate and can be set independently.

[0026] The reaction chamber heater 60 is located at the feed end of the spray head inside the reaction chamber 6.

[0027] Example 1: Comparative Example 1: Lanthanum precursor was used as the solid-state precursor source. The heating system used a uniformly controlled heating temperature, with the inlet heater 10, source bottle heater 20, outlet heater 30, steam delivery pipeline heater 40, valve heater 50, and reaction chamber heater 60 all controlled at 130-155℃. The reaction gas was O3, and the deposition cycle was 100 cycles. The GPC (Growth Per Cycle) fluctuated between 0.5 and 2 Å / cycle, with a non-uniformity index of 15-30, and the data varied significantly across multiple tests, exhibiting poor reproducibility. The step coverage was only 67%.

[0028] Example 1: In the solid precursor heating system provided by this invention, lanthanum precursor is selected as the solid precursor source. The temperature of the source bottle heater 20 is controlled within the range of 130-155℃ to maintain the stability of solid lanthanum. The temperature of the inlet heater 10 is controlled within the range of 110-130℃ to prevent carrier gas condensation. The temperature of the outlet heater 30 is controlled within the range of 130-160℃ to avoid vapor condensation. The temperature of the vapor delivery pipeline heater 40 is controlled within the range of 135-165℃ to ensure stable vapor delivery. The temperature of the valve heater 50 is controlled within the range of 140-170℃ to prevent condensation of the pneumatic valve 5. The temperature of the reaction chamber heater 60 is controlled within the range of 145-175℃ to achieve effective decomposition of solid lanthanum. The reaction gas is O3, and the deposition cycle is 100 cycles. GPC is stable and the non-uniformity is improved to below 3, and the step coverage is improved to 90% (compared to 67% in Comparative Example 1), showing a significant improvement over Comparative Example 1. Detailed results are shown in Table 1.

[0029] Example 2: Comparative Example 2: Hafnium precursor was used as the solid-state precursor source. The heating system used a uniformly controlled heating temperature, with the inlet heater 10, source bottle heater 20, outlet heater 30, vapor delivery pipeline heater 40, valve heater 50, and reaction chamber heater 60 all controlled at 160-190℃. The reaction gas was O3, and the deposition cycle was 100 cycles. GPC fluctuated between 0.3 and 1.8 Å / cycle, with a non-uniformity index of 20-30, and the data varied significantly across multiple tests, exhibiting poor reproducibility and a step coverage rate of only 72%. Example 2: In the solid-state precursor heating system provided by this invention, hafnium precursor is selected as the solid-state precursor source. The source bottle heater 20 is temperature-controlled within the range of 160-190℃ to maintain the stability of the solid hafnium. The inlet heater 10 is temperature-controlled within the range of 140-160℃ to prevent carrier gas condensation. The outlet heater 30 is temperature-controlled within the range of 165-195℃ to prevent vapor condensation. The vapor delivery pipeline heater 40 is temperature-controlled within the range of 170-200℃ to ensure stable vapor delivery. The valve heater 50 is temperature-controlled within the range of 175-200℃ to prevent condensation of the pneumatic valve 5. The reaction chamber heater 60 is temperature-controlled within the range of 190-220℃ to achieve effective decomposition of solid hafnium. The reaction gas is O3, and the deposition cycle is 100 cycles. GPC is stable and Non-uniformity is improved to below 3, and step coverage is improved to 97% (compared to 72% in Comparative Example 2), showing a significant improvement over Comparative Example 2. Detailed results can be found in Table 1.

[0030] Table 1:

[0031] Analysis reveals that in most existing solid precursor delivery processes (e.g., Comparative Examples 1 and 2), the heating temperature of the solid precursor source bottle typically needs to be higher than its sublimation temperature, and all components in the delivery system are usually heated to a uniform temperature range using a heating device. However, the sublimation point of the solid precursor source is relatively high, making the sealing rings and pneumatic valves used in the precursor source bottle highly susceptible to damage from high temperatures, leading to leakage risks and process anomalies. Furthermore, the solid precursor vapor is highly temperature sensitive; during delivery, temperature differences at bends and connections in the pipelines can cause precursor vapor condensation, resulting in pipeline blockage, preventing the solid precursor source from being delivered normally, and causing process failure.

[0032] Analysis of the solid precursor source revealed that sublimation occurs over a relatively wide temperature range. Therefore, by setting the heating temperature of the precursor source bottle at a lower point within the sublimation range and gradually increasing the temperature along the vapor transport direction (controlled within the temperature range), the precursor vapor can be smoothly transported into the ALD chamber for deposition. The relatively low sublimation temperature allows the solid precursor in the source bottle to sublimate at a relatively low and stable rate, maintaining a relatively stable solid-gas equilibrium. The carrier gas introduced through the inlet carries this gaseous precursor source out of the source bottle. Furthermore, because the outlet and downstream pipelines to the reaction chamber are in a state of gradually increasing temperature, gas transport can continue stably along the vapor transport direction, with no condensation at gas path bends, connectors, or gas valves. This method of gradually increasing the temperature of the precursor source delivered into the ALD chamber achieves excellent deposition uniformity, especially for high aspect ratio device structures, achieving high step coverage (>90%) (see Examples 1 and 2).

[0033] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0034] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A solid precursor delivery system for ALD process, comprising a solid precursor source bottle (2), a vapor delivery pipeline (4), a pneumatic valve (5), and a reaction chamber (6), wherein a carrier gas inlet (1) and a vapor outlet (3) are respectively provided on both sides of the top of the solid precursor source bottle; the vapor outlet (3) is connected to the inlet end of the vapor delivery pipeline (4); the inlet end of the pneumatic valve (5) is connected to the outlet end of the vapor delivery pipeline (4); and the reaction chamber (6) is connected to the outlet end of the pneumatic valve (5); characterized in that, It also includes heating components, The heating assembly includes an inlet heater (10) disposed at the carrier gas inlet (1), a source bottle heater (20) on the solid precursor source bottle (2), an outlet heater (30) on the steam outlet (3), a steam delivery pipeline heater (40) on the steam delivery pipeline (4), a valve heater (50) on the pneumatic valve (5), and a reaction chamber heater (60) on the top of the reaction chamber (6), and the heating temperatures of the inlet heater (10), the source bottle heater (20), the outlet heater (30), the steam delivery pipeline heater (40), the valve heater (50), and the reaction chamber heater (60) increase progressively.

2. A solid precursor delivery system for ALD process according to claim 1, characterized in that, The heating temperature of the inlet heater (10) is 100-160℃; the heating temperature of the source bottle heater (20) is 130-190℃; the heating temperature of the outlet heater (30) is 130-195℃; the heating temperature of the steam conveying pipeline heater (40) is 135-200℃; the heating temperature of the valve heater (50) is 140-200℃; and the heating temperature of the reaction chamber heater (60) is 145-220℃.

3. A solid precursor delivery system for ALD process according to claim 2, characterized in that, The inlet heater (10), the source bottle heater (20), the outlet heater (30), the steam delivery pipeline heater (40), the valve heater (50), and the reaction chamber heater (60) are each electrically connected to a temperature sensor.

4. A solid precursor delivery system for ALD process according to claim 3, characterized in that, Each of the temperature sensors is electrically connected to a temperature controller.

5. A solid precursor delivery system for ALD process according to claim 4, characterized in that, It also includes a central controller that is electrically connected to each of the thermostats and each of the temperature sensors.

6. A solid precursor delivery system for ALD process according to claim 4, characterized in that, The inlet heater (10), the source bottle heater (20), the outlet heater (30), the steam delivery pipeline heater (40), the valve heater (50), and the reaction chamber heater (60) all adopt heating insulation sleeves, which include insulation cotton and heating elements embedded in the insulation cotton.

7. A solid precursor delivery system for ALD process according to claim 4, characterized in that, The reaction chamber heater (60) is located at the feed end of the spray head inside the reaction chamber (6).

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