A quartz device suitable for use in low pressure chemical vapor deposition

Abstract

The application relates to a quartz device suitable for a low-pressure chemical vapor deposition method, which comprises a transverse cylindrical quartz boat shell, a first partition plate, a second partition plate and a third partition plate are vertically arranged in the quartz boat shell from right to left, a transverse cylindrical squirrel cage boat is arranged in the third cavity, a plurality of through holes are uniformly arranged on the circumferential surface of the squirrel cage boat, a central through hole is arranged in the center of the first partition plate, a plurality of air holes are uniformly arranged on the second partition plate and the third partition plate, and an air inlet is arranged at the bottom of the right end surface of the quartz boat shell. The application has the beneficial effects that the application can effectively improve the deposition unevenness phenomenon caused by the uneven flow velocity of the wafer surface, simultaneously reduce the film deposition of the inner wall of the furnace tube, and save the production cost.

Description

Technical Field

[0001] This invention relates to a quartz apparatus suitable for low-pressure chemical vapor deposition, belonging to the field of semiconductor device manufacturing. Background Technology

[0002] Quartz boats, as quartz products used in the semiconductor industry, have excellent corrosion resistance and high temperature resistance, and are generally used in important processes such as oxidation diffusion and LPCVD.

[0003] In semiconductor device fabrication processes, LPCVD is commonly used to prepare polycrystalline silicon and silicon oxide thin films, and quartz boats are commonly used wafer carriers. In typical processes, the quartz boat and flow uniform are directly fed into the furnace tube, and silane or other gases are introduced for the reaction. Due to the large overall volume of the furnace tube, the introduced gas diffuses throughout the cavity, forming a thick deposition layer on the inner wall of the furnace tube, shortening its lifespan. Furthermore, the high cost of cleaning and replacing the furnace tube increases the overall cost of industrial LPCVD production.

[0004] Meanwhile, in some existing technical solutions, in order to improve the uniformity and stability of the reaction gas, a porous flow equalizer is often placed at the front of the quartz boat. However, since the discrete flow equalizer has gaps with the inner wall of the furnace tube, most of the gas flow will flow through the gaps rather than the gas passage holes, resulting in an unsatisfactory flow equalization effect. Summary of the Invention

[0005] To address the above-mentioned technical shortcomings, this invention provides a quartz apparatus suitable for low-pressure chemical vapor deposition, which can effectively improve the uneven deposition phenomenon caused by uneven flow rate on the wafer surface.

[0006] This invention is achieved through the following measures:

[0007] A quartz apparatus suitable for low-pressure chemical vapor deposition includes a horizontally cylindrical quartz boat shell. Inside the quartz boat shell, from right to left, are vertically arranged a first partition, a second partition, and a third partition. A first cavity is formed between the right end face of the quartz boat shell and the first partition; a second cavity is formed between the first and second partitions; a third cavity is formed between the second and third partitions; and a fourth cavity is formed between the third partition and the left end face of the quartz boat shell. A horizontally cylindrical rat-cage boat is centrally located within the third cavity. Both ends of the rat-cage boat are equipped with sealing plates, and several through holes are evenly distributed on the circumference of the rat-cage boat. A central through hole is located in the center of the first partition, and several ventilation holes are evenly distributed on the second and third partitions. Two air inlets communicating with the first cavity are located at the bottom of the right end face of the quartz boat shell, and air inlets are connected to air intake components. An air outlet is located at the center of the left end face of the quartz boat shell.

[0008] According to a preferred embodiment of the present invention, the quartz boat shell is composed of an upper shell and a lower shell, which are sealed and fastened together and have semi-circular cross-sections. The first partition, the second partition, the third partition, the rat cage boat, and the sealing plate are all divided into upper and lower parts, which are respectively fixed inside the upper shell and the lower shell. When the upper shell and the lower shell are sealed and fastened together, the upper and lower parts of the first partition, the second partition, the third partition, the rat cage boat, and the sealing plate are also respectively sealed and connected. A semi-circular air outlet is opened at the center of the left end face of the upper shell, and a semi-circular air outlet is opened at the center of the left end face of the lower shell. When the upper shell and the lower shell are sealed and fastened together, the two semi-circular air outlets form a circular air outlet.

[0009] According to a preferred embodiment of the present invention, a plurality of through holes are provided on the circumferential surface of the rat cage boat, each group of through holes including a plurality of elongated through holes arranged in a row at axial intervals, and a plurality of Y-shaped wafer slots are provided on the inner sidewall of the rat cage boat, with the spacing between adjacent wafer slots being 1 to 2 cm.

[0010] According to a preferred embodiment of the present invention, the air intake assembly includes two quartz tubes arranged horizontally parallel to each other, and a plurality of curved quartz plates are longitudinally connected between the two quartz tubes. The ends of the quartz tubes are provided with conical air intake nozzles that match the air intake ports.

[0011] According to a preferred embodiment of the present invention, four transverse quartz rods are provided between the second and third partitions in the upper housing and between the second and third partitions in the lower housing, and the rat cage boat is fixed on the quartz rods.

[0012] According to a preferred embodiment of the present invention, the diameter of the vent holes on the second and third partitions is 0.6-0.8 cm.

[0013] The beneficial effects of this invention are: this invention can effectively improve the uneven deposition phenomenon caused by uneven flow rate on the wafer surface, while reducing the film deposition on the inner wall of the furnace tube, saving production costs, and ensuring uniform flow rate in all directions and uniform flow rate on the wafer surface, with an average flow rate of 8.223E-4m / s. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0015] Figure 2 This is a schematic diagram of the upper shell structure of the present invention;

[0016] Figure 3 This is a schematic diagram of the lower housing of the present invention;

[0017] Figure 4 A schematic diagram of the structure of a rat cage boat;

[0018] Figure 5 This is a schematic diagram of the wafer slot structure;

[0019] The components are: 1. Quartz boat shell, 2. Air inlet, 3. Quartz tube, 4. Quartz plate, 5. Upper shell, 6. First partition, 7. Second partition, 8. Sealing plate, 9. Rat cage boat, 10. Third partition, 11. Quartz rod, 12. Lower shell, 13. Air inlet. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings:

[0021] The technical problems to be solved by this invention are: 1. improving the uniformity of thin film deposition; 2. reducing the thin film deposition on the inner wall of the furnace tube in the LPCVD process, thereby saving production costs.

[0022] like Figure 1-5 As shown, a quartz apparatus suitable for low-pressure chemical vapor deposition includes a horizontally cylindrical quartz boat shell 1. Inside the quartz boat shell 1, from right to left, are vertically arranged a first partition 6, a second partition 7, and a third partition 10. A first cavity is formed between the right end face of the quartz boat shell 1 and the first partition 6; a second cavity is formed between the first partition 6 and the second partition 7; a third cavity is formed between the second partition 7 and the third partition 10; and a fourth cavity is formed between the third partition 10 and the left end face of the quartz boat shell 1. A transverse cylindrical cage boat 9 is centrally located within the third cavity. Both ends of the cage boat 9 are equipped with sealing plates 8, and several through holes are evenly distributed on its circumference. A central through hole is located in the center of the first partition 6, and several ventilation holes are evenly distributed on the second partition 7 and the third partition 10. Two air inlets 2, connected to the first cavity, are located at the bottom right end of the quartz boat shell 1. Air inlets 2 are connected to air intake components. An air outlet is located at the center of the left end of the quartz boat shell 1. This structure ensures that the reactant gases mainly concentrate and diffuse within each chamber, reducing diffusion within the furnace tubes.

[0023] The quartz boat shell 1 consists of an upper shell 5 and a lower shell 12, both of which are semi-circular in cross-section and are sealed together. The upper shell 5 and the lower shell 12 are connected by pre-reserved slots to form the quartz boat shell 1. The first partition 6, the second partition 7, the third partition 10, the cage boat 9, and the sealing plate 8 are each divided into upper and lower parts, which are respectively fixed inside the upper shell 5 and the lower shell 12. When the upper shell 5 and the lower shell 12 are sealed together, the upper and lower parts of the first partition 6, the second partition 7, the third partition 10, the cage boat 9, and the sealing plate 8 are also sealed together. A semi-circular air outlet is opened at the center of the left end face of the upper shell 5, and a semi-circular air outlet is opened at the center of the left end face of the lower shell 12. When the upper shell 5 and the lower shell 12 are sealed together, the two semi-circular air outlets form a circular air outlet.

[0024] The cage boat 9 has several sets of through holes on its circumferential surface. Each set of through holes includes several elongated through holes arranged in a row at axial intervals. Several Y-shaped wafer slots are provided on the inner wall of the cage boat 9, with a spacing of 1-2 cm between adjacent wafer slots. This structure facilitates the formation of turbulent flow zones on the wafers, mitigating the "center effect" of deposition to some extent and ensuring uniformity. The cage boat 9 employs a twelve-directional perforation design. Compared to traditional structures, this new structure effectively improves the uniformity of flow velocity on the wafer surface, prevents "fogging" defects caused by rapid edge gas intake, and enhances deposition uniformity. The wafer loading structure is located at the bottom of the cage boat 9 and consists of three thin quartz rods. The wafer slots are Y-shaped. This shape reduces the impact of slot depth on deposition, improves uniformity, and effectively prevents wafers from adhering to the quartz boat.

[0025] The air intake assembly includes two quartz tubes 3, which are arranged horizontally parallel to each other. Several curved quartz plates 4 are longitudinally connected between the two quartz tubes 3. A conical air inlet 13, matching the air inlet 2, is provided at the end of each quartz tube 3. When the paddle descends into the boat, the air inlet 13 couples with the air inlet 2. The air inlet 2 is designed to be slightly larger, allowing for some tolerance. Four horizontal quartz rods 11, each 1 cm in diameter, are provided between the second partition 7 and the third partition 10 inside the upper shell 5, and between the second partition 7 and the third partition 10 inside the lower shell 12. The squirrel-cage boat 9 is fixed to the quartz rods 11. The ventilation holes on the second partition 7 and the third partition 10 have a diameter of 0.6-0.8 cm and are arranged in a sprinkler-like pattern.

[0026] Gas flows into the first chamber through inlet 2, then concentrates and enters the second chamber through the central through-hole in the middle of the first partition 6. It then enters the third chamber through the vent inlet of the second partition 7, generating a stable laminar flow. Some gas diffuses into the cage boat 9 through the vent and reacts, while the remaining gas enters the fourth chamber through the third partition 10 and then flows out through the outlet. The second partition 7 and the third partition 10 are symmetrically designed to ensure stable airflow.

[0027] The above description is only a preferred embodiment of this patent. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this patent, and these improvements and substitutions should also be considered within the scope of protection of this patent.

Claims

1. A quartz apparatus suitable for low-pressure chemical vapor deposition, characterized in that: The device includes a horizontally cylindrical quartz boat shell. Inside the quartz boat shell, from right to left, are vertically arranged a first partition, a second partition, and a third partition. A first cavity is formed between the right end face of the quartz boat shell and the first partition; a second cavity is formed between the first and second partitions; a third cavity is formed between the second and third partitions; and a fourth cavity is formed between the third partition and the left end face of the quartz boat shell. A horizontally cylindrical mouse cage boat is centrally located within the third cavity. Both ends of the mouse cage boat are equipped with sealing plates, and the mouse... The cage boat has several sets of through holes on its circumference. Each set of through holes includes several long strip-shaped through holes arranged in a row at axial intervals. The inner sidewall of the cage boat has several Y-shaped wafer slots with a spacing of 1-2 cm between adjacent wafer slots. The first partition has a central through hole in its center. The second and third partitions have several ventilation holes evenly distributed. The bottom right end face of the quartz boat shell has two air inlets connected to the first cavity. The air inlets are connected to an air intake assembly. The center left end face of the quartz boat shell has an air outlet. The quartz boat shell consists of an upper shell and a lower shell, both of which are semi-circular in cross-section and are sealed together. The first partition, the second partition, the third partition, the rat cage boat, and the sealing plate are each divided into upper and lower parts, which are fixed inside the upper shell and the lower shell, respectively. When the upper shell and the lower shell are sealed together, the upper and lower parts of the first partition, the second partition, the third partition, the rat cage boat, and the sealing plate are also sealed together. A semi-circular air outlet is opened at the center of the left end face of the upper shell, and a semi-circular air outlet is opened at the center of the left end face of the lower shell. When the upper shell and the lower shell are sealed together, the two semi-circular air outlets form a circular air outlet.

2. The quartz apparatus for low-pressure chemical vapor deposition according to claim 1, characterized in that: The air intake assembly includes two quartz tubes arranged horizontally in parallel, and several curved quartz plates are longitudinally connected between the two quartz tubes. The ends of the quartz tubes are provided with conical air intake nozzles that match the air intake ports.

3. The quartz apparatus for low-pressure chemical vapor deposition according to claim 1, characterized in that: Four transverse quartz rods are provided between the second and third partitions in the upper shell and between the second and third partitions in the lower shell, and the rat cage boat is fixed on the quartz rods.

4. The quartz apparatus for low-pressure chemical vapor deposition according to claim 1, characterized in that: The diameter of the vent holes on the second and third partitions is 0.6-0.8 cm.

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