Vertical double-temperature-zone CVD (chemical vapor deposition) equipment with high temperature and gas uniformity

Abstract

The invention discloses vertical double-temperature-zone CVD (chemical vapor deposition) equipment with high temperature and gas uniformity, which comprises a vertical quartz tube in which a substrate table is arranged, the substrate table divides the quartz tube into an upper temperature zone and a lower temperature zone, and each temperature zone is heated by an electromagnetic induction heating device; the throttle valve is provided with a flow sensor and is used for controlling the flow of the gas and realizing the uniformity of the flowing of the gas flow; and the substrate slice is arranged on the substrate table, and uniform film deposition is achieved by controlling the horizontal rotating speed of the substrate table and the distance between the substrate table and the air inlet. The surface quality and uniformity of the deposited film can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor equipment, and particularly relates to a vertical double-temperature zone CVD equipment with high temperature and gas uniformity. Background Art

[0002] As a versatile thin film deposition technology, chemical vapor deposition (CVD) has high flexibility and adaptability, and is suitable for the large-area deposition of various materials (such as metals, semiconductors, insulators, and dielectrics, etc.). It has been widely used in the manufacturing of semiconductors, microelectronics, and advanced materials. With the continuous development of semiconductor materials and the chip industry, higher requirements have been put forward for the surface quality and uniformity of CVD-deposited thin films. In horizontal CVD equipment, the gas blows from the side near the gas inlet of the substrate wafer to the side near the gas outlet, and at the same time, there is a lack of means to adjust the gas flow rate and flow direction, which easily causes gas turbulence, resulting in uneven adsorption of the reaction precursor on the surface of the substrate wafer, and further leading to uneven thickness and composition during the film growth process. At the same time, CVD equipment usually uses resistance heating for temperature control, which is prone to the adverse situation of "temperature linkage", and the temperature conduction of the resistance heating method is slow, and the temperature control accuracy is limited, which also affects the surface quality and uniformity of the deposited thin film. Summary of the Invention

[0003] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the purpose of the present invention is to provide a vertical double-temperature zone CVD equipment with high temperature and gas uniformity.

[0004] The purpose of the present invention is achieved through the following technical solutions: A vertical double-temperature zone CVD equipment with high temperature and gas uniformity, comprising: A quartz tube, which is vertical, and a substrate stage is arranged inside it. The substrate stage divides the quartz tube into upper and lower two temperature zones, and each temperature zone is heated by an electromagnetic induction heating device; A throttle valve, which is provided with a flow sensor for controlling the gas flow rate to achieve the uniformity of gas flow; A substrate wafer, which is arranged on the substrate stage, and the uniformity of the deposited thin film is achieved by controlling the horizontal rotation speed of the substrate stage and the distance between the substrate stage and the gas inlet.

[0005] Further, a film thickness gauge is arranged on the substrate stage for testing the thickness of the deposited film on the substrate stage.

[0006] Further, an adjustment hole is arranged inside the throttle valve, and the adjustment hole is a porous plate structure.

[0007] Further, the substrate stage is provided with four accommodating grooves for placing the substrate wafers to be processed.

[0008] Furthermore, the substrate stage fixes the substrate wafer by means of negative pressure suction.

[0009] Furthermore, there is no gap between the two temperature zones.

[0010] Furthermore, the horizontal rotation speed is driven by a horizontal driving device, and the horizontal driving device is provided with a rotation speed button, and the angular velocity of the horizontal rotation of the substrate stage is adjusted by changing the input voltage of the motor inside the horizontal driving device.

[0011] Furthermore, when the actual film deposition speed is greater than or less than the set speed, the substrate stage moves vertically to control the distance between the substrate stage and the air inlet, adjust the concentration of the gas precursor on the surface of the substrate stage, and ensure that the actual film deposition speed is equal to the set speed.

[0012] Furthermore, for the reducing atmosphere, hydrogen is added to the inert carrier gas, and the gas mixing ratio is 5:1.

[0013] Furthermore, for the film growth thickness of two-dimensional materials, it is achieved by controlling the distance between the substrate wafer and the precursor and the growth time.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects: A vertical quartz tube is adopted and is combined with a throttle valve with a gas flow rate control system to ensure the uniformity of the gas flow rate and flow direction inside the quartz tube. At the same time, an electromagnetic induction heating device is adopted to replace the resistance heating device to achieve faster and more accurate temperature control, thereby improving the surface quality and uniformity of the deposited film. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a vertical dual-temperature zone CVD device with high temperature and gas uniformity of the present invention; Figure 2 is Figure 1 the structural schematic diagram of the substrate stage when viewed from above; Figure 3 is the AFM image of the GaN film deposited by using the vertical dual-temperature zone CVD device with high temperature and gas uniformity of the present invention; Figure 4 is the AFM image of the GaN film deposited by using the existing horizontal single-temperature zone CVD device. SPECIFIC EMBODIMENTS

[0016] The following will further describe the present invention in detail in conjunction with embodiments, but the embodiments of the present invention are not limited thereto.

[0017] Embodiment 1 As Figure 1 and Figure 2As shown in the figure, a vertical dual-temperature zone CVD device with high temperature and gas uniformity includes: A quartz tube, which is vertical. A substrate table 5 is arranged inside it. The substrate table divides the quartz tube into upper and lower temperature zones. Each temperature zone is heated by an electromagnetic induction heating device 9. The substrate table 5 is used to accommodate the substrate wafer to be deposited. The substrate table 5 is connected with a circular rotating guide rail 6 and a horizontal driving device 7. The horizontal driving device 7 can drive the substrate table 5 to rotate horizontally along the circular rotating guide rail. The substrate table is connected with a temperature sensor 10 and a film thickness meter 11.

[0018] Further explanation: In the prior art, in order to cooperate with large-size growth, the carrier gas flow is very slow, and it is impossible to ensure that the gas flows through the entire tube, so the pressure distribution inside the pipeline is uneven. If this problem is to be solved by increasing the gas flow rate, the material deposition efficiency will be reduced, resulting in a decrease in the nucleation rate and a decline in the material growth quality. This device adopts a horizontal driving device that can drive the substrate table 5 to rotate horizontally along the circular rotating guide rail, so that the sample cannot simply stay in a specific area to contact the precursor, ensuring uniform gas flow.

[0019] When depositing thin films of different materials, the deposition uniformity can be adjusted by the rotation speed.

[0020] A throttle valve 1, which has a gas channel and an adjusting hole with a porous structure inside, is used to control the gas flow rate and improve the gas flow uniformity.

[0021] The throttle valve 1 is connected with a gas flow rate control system 2. The gas flow rate control system includes a flow sensor 3 and a control driver 4. The throttle valve has a gas channel and an adjusting hole with a porous structure inside, which is used to control the gas flow rate and improve the gas flow uniformity.

[0022] Further explanation: During the actual growth process, it is not necessary to introduce gas throughout the process. The purpose is to prevent unevenness caused by premature reaction, and a throttle valve is needed to control the gas intake time. Or a mixture of multiple gases is required. A substrate wafer 13 is arranged on the substrate table. By controlling the horizontal rotation speed of the substrate table and the distance between the substrate table and the gas inlet, the uniformity of the deposited thin film is achieved. The distance between the substrate table and the gas inlet is realized by a substrate table lifting system 8, which drives the substrate table to move vertically.

[0023] In this embodiment, preferably, the adjusting hole inside the throttle valve 1 is designed as a porous plate structure, so that when the gas enters the quartz tube, it can be distributed as evenly as possible to form a more stable laminar flow state, reducing the occurrence of turbulence and eddy currents, thereby improving the gas uniformity.

[0024] In this embodiment, preferably, the substrate table 5 is provided with 4 1 cm 2 ×1 cm2 A placement groove 14 of a certain size is used to place the substrate wafer to be processed. Additionally, it should be noted that in order to prevent the substrate wafer from falling off, the substrate stage 5 can suck the substrate wafer tightly through a negative pressure suction method; as an alternative setting method, the substrate stage 5 can be plugged and unplugged with a transparent card to hold the substrate wafer, or the substrate wafer can also be fixed by a magnetic attraction method, etc.

[0025] In this embodiment, preferably, the substrate stage 5 is equipped with a temperature sensor 10 for real-time detection of the temperature of the substrate wafer. The electromagnetic induction heating device 9 is equipped with a temperature controller 12, and the temperature sensor 10 and the temperature controller 12 are electrically connected through a drive circuit to ensure that the actual temperature detected by the temperature sensor 10 is consistent with the temperature set by the CVD equipment program.

[0026] In this embodiment, preferably, the horizontal drive device 7 is connected with a rotation speed knob, and the angular velocity of the horizontal rotation of the substrate stage is adjusted by changing the input voltage of the motor inside the horizontal drive device 7, so as to ensure the uniformity of the deposited film.

[0027] In this embodiment, preferably, the substrate stage 5 is equipped with a film thickness gauge 12 for real-time detection of the film deposition rate. The film thickness gauge 12 and the substrate stage lifting system 8 are electrically connected through a drive circuit. When the actual film deposition rate is greater than or less than the set rate, the film thickness gauge 12 drives the substrate stage lifting system 8 through the drive circuit to move the substrate stage 5 vertically, control the distance between the substrate stage 5 and the air inlet, thereby adjusting the gas precursor concentration on the surface of the substrate stage, and further ensuring that the actual film deposition rate is consistent with the set rate. Taking the growth of layered MoS2 on a SiO2 substrate by CVD method as an example, the Ar flow rate is set to 70 sccm, the upper and lower temperature zones are 780 °C and 180 °C respectively, 5 mg of MoO3 and 120 mg of sulfur powder are put in as precursors. To ensure the large-area uniform growth of layered MoS2, the deposition rate is set to 0.05 nm / min. If the distance between the SiO2 substrate and the air inlet is 10 cm, the deposition rate of MoS2 reaches 0.1 nm / min, exceeding the set deposition rate. At this time, the substrate stage 5 will be driven by the substrate stage lifting system 8 to move away from the air inlet until the actual deposition rate drops to 0.05 nm / min.

[0028] In this embodiment, preferably, the heating zone lengths of the upper and lower temperature zones of the electromagnetic induction heating device 9 are both 200 mm, and there is no interval between the two heating zones, so as to ensure the uniform distribution of the temperature gradient inside the heating zone, which helps to obtain a high-quality deposited film.

[0029] The control process of processing two-dimensional materials using this equipment is as follows: The gas flow rate of the throttle valve is set between 100 sccm and 200 sccm. If hydrogen is added, 20 sccm of hydrogen is mixed with 100 sccm of inert gas (the ratio is 1:5). For growing continuous films, generally a lower gas flow rate is used. For the distance between the substrate and the precursor, for a 1 cm × 1 cm chip when growing a continuous film, the distance is generally between 1.5 cm and 2 cm. If growing grains, a distance > 3 cm is safer as the grain size is relatively small at this time. The rotation speed is set between 80 rpm and 100 rpm.

[0030] Example 2 Using the vertical two - temperature - zone CVD equipment with the above - mentioned high temperature and gas uniformity, place the Ga2O3 thin film obtained by magnetron sputtering on the substrate stage. Control the substrate stage lifting system so that the distance between the substrate stage and the air inlet is 50 cm. Evacuate to a pressure inside the quartz tube lower than 1×10 -4 Torr. Set the temperature of the upper temperature zone to 850 °C, the temperature of the lower temperature zone to 800 °C, the heating rate to 10 °C / min. Continuously introduce argon during the heating process, with an argon flow rate of 50 sccm. When the temperatures of the upper and lower temperature zones reach the set values, start introducing NH3, control the gas flow rate to be 15 sccm, and continue for 10 min to ensure that the Ga2O3 thin film is completely nitrided to form a GaN thin film.

[0031] Comparative example Use a common horizontal single - temperature - zone CVD equipment, model OTF - 1200X (Hefei Kejing Materials Technology Co., Ltd.). Similarly, place the Ga2O3 thin film obtained by magnetron sputtering inside the quartz tube, keep the distance between the sample and the air inlet at 50 cm, evacuate to a pressure inside the quartz tube lower than 1×10 -4 Torr. Set the temperature of the temperature zone to 850 °C, the heating rate to 10 °C / min. Continuously introduce argon during the heating process, with an argon flow rate of 50 sccm. When the temperature of the temperature zone reaches the set value, start introducing NH3, control the gas flow rate to be 15 sccm, and continue for 10 min to ensure that the Ga2O3 thin film is completely nitrided to form a GaN thin film.

[0032] Test the GaN thin films obtained in Example 1 and Comparative Example 1 through AFM testing. The AFM test results are as Figures 3-4 shown. The surface roughness of the GaN thin film in Example 1 is 0.2 nm, while the surface roughness of the GaN thin film in Comparative Example 1 is 1.7 nm. Thus, compared with the common horizontal single - temperature - zone CVD equipment, the vertical two - temperature - zone CVD equipment with high temperature and gas uniformity of the present invention can ensure the gas flow rate, uniformity, and temperature uniformity inside the quartz tube, thereby improving the surface quality and uniformity of the deposited thin film.

[0033] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A vertical double-temperature zone CVD device with high temperature and gas uniformity, characterized in that, Including: A quartz tube, which is vertical. A substrate table is arranged inside it. The substrate table divides the quartz tube into upper and lower temperature zones, and each temperature zone is heated by an electromagnetic induction heating device; A throttle valve, which is provided with a flow sensor to control the gas flow rate and achieve the uniformity of gas flow; A substrate wafer, which is arranged on the substrate table. By controlling the horizontal rotation speed of the substrate table and the distance between the substrate table and the air inlet, the uniformity of the deposited film is achieved.

2. The vertical dual-temperature zone CVD equipment according to claim 1, wherein The substrate table is provided with a film thickness gauge for testing the thickness of the deposited film on the substrate table.

3. The vertical dual-temperature zone CVD device according to claim 1, wherein An adjustment hole is arranged inside the throttle valve, and the adjustment hole is a perforated plate structure.

4. The vertical dual-temperature zone CVD equipment according to any one of claims 1 or 2, characterized in that, The substrate table is provided with four accommodating grooves for placing the substrate wafers to be processed.

5. The vertical dual-temperature zone CVD equipment according to claim 4, characterized in that, The substrate table fixes the substrate wafer by means of negative pressure suction.

6. The vertical dual-temperature zone CVD equipment according to claim 1, wherein, There is no interval between the two temperature zones.

7. The vertical dual-temperature zone CVD device according to claim 6, wherein, The horizontal rotation speed is driven by a horizontal driving device. The horizontal driving device is provided with a rotation speed button, and the angular velocity of the horizontal rotation of the substrate table is adjusted by changing the input voltage of the motor inside the horizontal driving device.

8. The vertical dual-temperature zone CVD equipment according to claim 1, wherein When the actual speed of film deposition is greater than or less than the set speed, the substrate table moves vertically to control the distance between the substrate table and the air inlet, adjust the concentration of the gas precursor on the surface of the substrate table, and ensure that the actual film deposition speed is equal to the set speed.

9. The vertical dual-temperature zone CVD equipment according to claim 1, wherein For a reducing atmosphere, hydrogen is added to the inert carrier gas, and the gas mixing ratio is 5:

1.

10. The vertical dual-temperature zone CVD equipment according to claim 1, wherein For the film growth thickness of two-dimensional materials, it is achieved by controlling the distance between the substrate wafer and the precursor and the growth time.

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