Device and process for producing high-quality synthetic quartz blank

Abstract

The invention relates to the technical field of quartz blank synthesis, and particularly discloses a device and process for producing a high-quality synthetic quartz blank, the device comprises a closed furnace body, a deposition chamber is arranged in the closed furnace body, one side of the closed furnace body is provided with a raw material burner and an auxiliary burner, the raw material burner is located below the auxiliary burner, and the deposition chamber is communicated with the deposition chamber. An air inlet device is further installed above the auxiliary combustor, and the other side of the closed furnace body is connected with an air draft device through a pipeline. The device is used for producing a high-quality synthetic quartz blank, the position and the shape of the suction opening in the edge of the cavity are optimized, then airflow in the deposition cavity is stabilized, flame fluctuation is reduced, the temperature gradient is homogenized, the cracking rate of a loose body produced through the device is smaller than or equal to 0.5%, homogenization treatment in the later procedure is facilitated, and the production efficiency is improved. Under the same conditions of other processes and devices, the quartz blank produced by using the device is smaller in hydroxyl radial distribution concentration difference value and better in optical non-uniformity value.

Description

Technical Field

[0001] The invention relates to the technical field of quartz blank synthesis, in particular to a device and a process for producing high-quality synthetic quartz blank. Background Art

[0002] Quartz glass is an amorphous material composed of a single component, silicon dioxide. It is a special industrial technical glass with the characteristics of high temperature resistance, low expansion coefficient, thermal shock resistance, chemical stability and good electrical insulation properties. It can also transmit ultraviolet and infrared rays. It is used in the manufacture of semiconductors, electric light sources, semiconductor communication devices, lasers, optical instruments and other industries, and is widely used.

[0003] The main preparation methods of synthetic quartz include CVD, VAD, PCVD and sol-gel methods, which are mainly made of silicon dioxide by hydrolysis and oxidation of silicides (SiCl4, silicone D4, etc.). Synthetic quartz has different performances in SiO2 purity, hydroxyl content and other indicators due to different preparation methods, resulting in different material properties.

[0004] Quartz glass is mainly produced by two categories: crystal melting quartz glass manufacturing process and synthetic quartz glass manufacturing process. The former includes vacuum electric melting process, two-step melting process, continuous melting process, powder gas refining direct tube making process, powder gas refining lump making process, etc. The latter includes chemical vapor deposition (CVD) process, vapor axial deposition (VAD) process, plasma chemical vapor deposition (PCVD) process, etc. Compared with natural quartz, synthetic quartz has the advantages of high far-ultraviolet transmittance, high optical uniformity, and excellent radiation resistance because it uses high-purity silicide as raw material. However, although the quartz prepared by CVD is of high purity, its deposition cycle is long and the quartz glass produced by CVD has a high hydroxyl content of up to 1000ppm, which cannot be used in the infrared field. Although the quartz glass produced by PCVD has a low hydroxyl content, the Cl content is far above the standard, up to 200ppm, which affects the light transmittance in the ultraviolet band.

[0005] Compared with the above two methods, VAD belongs to an indirect synthesis method. The process characteristics of this synthesis method are: high deposition efficiency, fast rate, controllable hydroxyl content, and simple process route. The raw materials are SiCl4 and hydroxyl, which have a wide source and low cost.

[0006] However, the current VAD method for preparing high-purity infrared quartz glass involves intermediate semi-finished products, loose bodies, before obtaining quartz rod blanks. Because the loose body is composed of sticky silica particles, its density is generally 0.2-0.5g / cm 3This characteristic makes it easy to crack during the production process. Although the cracking problem can be optimized by adjusting the process parameters, it will also cause limitations in process adjustment. Therefore, a device and process for producing high-quality synthetic quartz blanks are provided. Summary of the invention

[0007] The purpose of the present invention is to provide a device and process for producing high-quality synthetic quartz blanks in view of the defects of the prior art, so as to solve the problems raised by the above-mentioned background technology.

[0008] To achieve the above-mentioned object, the present invention provides the following technical solution: a device for producing high-quality synthetic quartz blanks, comprising a closed furnace body, a deposition chamber is arranged inside the closed furnace body, a raw material burner and an auxiliary burner are installed on one side of the closed furnace body, the raw material burner is located below the auxiliary burner, an air inlet device is also installed above the auxiliary burner, an exhaust device is connected to the other side of the closed furnace body through a pipeline, the pipeline passes through the side wall of the closed furnace body and is connected to the exhaust hood in the deposition chamber, and an automatic pressure regulating valve is installed on the pipeline;

[0009] A lifting and rotating device is installed on the top of the closed furnace body, and a loose body is connected to the bottom of the lifting and rotating device.

[0010] As a preferred technical solution of the present invention, the lifting and rotating device includes a first motor, a connecting plate, a second motor, an electric telescopic rod, a deposition guide rod connecting head, a target rod, and a deposition guide rod; the main shaft of the first motor is fixedly connected to the electric telescopic rod and the second motor installed on the electric telescopic rod through the connecting plate, the telescopic end of the electric telescopic rod is connected to the deposition guide rod, and the deposition guide rod is connected to the target rod through the deposition guide rod connecting head.

[0011] As a preferred technical solution of the present invention, the number of the raw material burners and the auxiliary burners are both several, and the raw material burners and the auxiliary burners are both installed on the closed furnace body by bolts.

[0012] As a preferred technical solution of the present invention, the air inlet device is connected to the closed furnace body, and a fan is installed inside the air inlet device.

[0013] As a preferred technical solution of the present invention, the exhaust hood is arc-shaped, the exhaust hood is connected to the exhaust device through a pipeline, a fan is installed in the exhaust device, and the exhaust hood is installed on the side wall of the closed furnace body by bolts.

[0014] As a preferred technical solution of the present invention, the air inlet device, the air exhaust device and the lifting and rotating device are all electrically connected to an external control switch.

[0015] A process for producing high-quality synthetic quartz blanks is implemented using the above device, and the specific steps are as follows:

[0016] Step 1: Check the cleanliness of the deposition chamber in the closed furnace body, install the target rod on the deposition guide rod connector, start the first motor to rotate, and check the wobble of the target rod. The rotation speed is required to be set in the range of 1rpm-60rpm, and the radial wobble of the target rod is ≤1mm;

[0017] Step 2: The raw material burner and the auxiliary burner preheat the deposition chamber and the target rod, and the hydrogen and oxygen content of the burner is gradually increased. When the temperature of the target rod reaches 800℃-900℃, the raw material burner is introduced with high-purity raw materials. The high-purity raw materials use high-purity oxygen as a carrier gas, and the negative pressure value of the cavity is set. The negative pressure of the deposition chamber is controlled to be maintained at -70Pa±2Pa through the exhaust device. The second motor on the electric telescopic rod works at a uniform speed, and the speed setting value is 0.6mm / min-1.5mm / min;

[0018] Step 3: After continuous step 2 for 30 hours of deposition, a loose body with a size of φ500mm*1500mm is obtained;

[0019] Step 4: The loose body obtained in step 3 is subjected to vitrification sintering treatment to obtain a product with a typical value of 90% caliber uniformity of <2ppm.

[0020] As a preferred technical solution of the present invention, the high-purity raw material in step 2 is SiCl4 or polysiloxane, and the purity of the carrier gas is 9N grade.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: the device of the present invention is used to produce high-quality synthetic quartz blanks, and by optimizing the position and shape of the exhaust port at the edge of the cavity, the airflow inside the deposition chamber is stabilized, the flame fluctuation is reduced, and the temperature gradient is homogenized. The cracking rate of the loose body produced by the device is ≤0.5%, and the subsequent homogenization treatment is convenient. Under the same conditions of other processes and devices, the quartz blanks produced by the device have a smaller difference in radial distribution concentration of hydroxyl groups and a better optical non-uniformity value. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention;

[0023] Figure 2 It is a structural schematic diagram of the lifting and rotating device of the present invention.

[0024] In the figure: 1. raw material burner; 2. auxiliary burner; 3. air inlet device; 4. loose body; 5. exhaust device; 6. automatic pressure regulating valve; 7. closed furnace body; 8. lifting and rotating device; 9. exhaust hood; 801. first motor; 802. connecting plate; 803. second motor; 804. electric telescopic rod; 805. deposition guide rod connector; 806. target rod; 807. deposition guide rod. DETAILED DESCRIPTION

[0025] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0026] Example: See Figure 1-2 The present invention provides a technical solution: a device for producing high-quality synthetic quartz blanks, comprising a closed furnace body 7, a deposition chamber is arranged inside the closed furnace body 7, a raw material burner 1 and an auxiliary burner 2 are installed on one side of the closed furnace body 7, the raw material burner 1 is located below the auxiliary burner 2, an air inlet device 3 is also installed above the auxiliary burner 2, an exhaust device 5 is connected to the other side of the closed furnace body 7 through a pipeline, the pipeline passes through the side wall of the closed furnace body 7 and is connected to the exhaust hood 9 in the deposition chamber, and an automatic pressure regulating valve 6 is installed on the pipeline;

[0027] A lifting and rotating device 8 is installed on the top of the closed furnace body 7, and a loose body 4 is connected to the bottom of the lifting and rotating device 8.

[0028] The lifting and rotating device 8 includes a first motor 801, a connecting plate 802, a second motor 803, an electric telescopic rod 804, a deposition guide rod connector 805, a target rod 806, and a deposition guide rod 807; the main shaft of the first motor 801 is fixedly connected to the electric telescopic rod 804 and the second motor 803 installed on the electric telescopic rod 804 through the connecting plate 802, the telescopic end of the electric telescopic rod 804 is connected to the deposition guide rod 807, and the deposition guide rod 807 is connected to the target rod 806 through the deposition guide rod connector 805; the first motor 801 is used to drive the connecting plate 802 to rotate, thereby driving the electric telescopic rod 804 on the connecting plate 802 to rotate, and the second motor 803 is used to drive the electric telescopic rod 804 to work to achieve lifting.

[0029] There are several raw material burners 1 and several auxiliary burners 2, and the raw material burners 1 and auxiliary burners 2 are both mounted on the closed furnace body 7 by bolts.

[0030] The air inlet device 3 is communicated with the closed furnace body 7 , and a fan is installed inside the air inlet device 3 .

[0031] The exhaust hood 9 is arc-shaped and is connected to the exhaust device 5 through a pipeline. A fan is installed in the exhaust device 5. The exhaust hood 9 is installed on the side wall of the closed furnace body 7 by bolts. The opening angle of the exhaust hood 9 can be adjusted according to the actual loose body size and demand.

[0032] The air inlet device 3, the air exhaust device 5 and the lifting and rotating device 8 are all electrically connected to an external control switch, and the air inlet device 3, the air exhaust device 5 and the lifting and rotating device 8 are powered on and operated by the external control switch.

[0033] Working principle: A process for producing high-quality synthetic quartz blanks is implemented using the device of the present invention, and the specific steps are as follows:

[0034] Step 1: Check the cleanliness of the deposition chamber in the closed furnace body 7, install the target rod 806 on the deposition guide rod connector 805, start the first motor 801 to rotate, and check the wobble of the target rod 806. The rotation speed is required to be set in the range of 1rpm-60rpm, and the radial wobble of the target rod 806 is ≤1mm;

[0035] Step 2: The raw material burner 1 and the auxiliary burner 2 preheat the deposition chamber and the target rod 806, and the hydrogen and oxygen content of the burner is gradually increased. When the temperature of the target rod 806 reaches 800°C-900°C, the raw material burner 1 is introduced with high-purity raw materials. The high-purity raw materials use high-purity oxygen as a carrier gas (purity is 9N grade), and the cavity negative pressure value is set. The vacuum pressure of the deposition chamber is controlled to be maintained at -70Pa±2Pa through the exhaust device 5. The second motor 803 on the electric telescopic rod 804 works at a uniform speed, and the speed setting value is 0.6mm / min-1.5mm / min;

[0036] Step 3: After continuous step 2 for 30 hours of deposition, a loose body with a size of φ500mm*1500mm is obtained;

[0037] Step 4: The loose body obtained in step 3 is subjected to vitrification sintering treatment, and a typical value of product uniformity can be obtained to reach <2ppm (D220mm@90% caliber).

[0038] Since the indirect synthesis method first generates a loose body composed of SiO2 particles, this step is prone to uneven density distribution, which may lead to cracking of the loose body, resulting in waste and increased costs. Therefore, the present invention optimizes the shape of the deposition hood, improves the airflow inside the cavity, and optimizes the temperature gradient inside the deposition chamber, thereby improving the density distribution of the loose body and reducing the cracking rate. The opening angle of the hood can be adjusted according to the actual size of the loose body and demand. According to actual data statistics, a total of 200 loose bodies have been produced, and the cracking rate is less than 0.5%. The loose bodies produced by the device of the present invention can achieve a typical value of product uniformity of <2ppm (D220mm@90% caliber) after subsequent process flow.

[0039] The above embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A device for producing high-quality synthetic quartz blanks, comprising a closed furnace body (7), characterized in that: The closed furnace body (7) is provided with a deposition chamber inside, a raw material burner (1) and an auxiliary burner (2) are installed on one side of the closed furnace body (7), the raw material burner (1) is located below the auxiliary burner (2), and an air inlet device (3) is installed above the auxiliary burner (2), and the other side of the closed furnace body (7) is connected to an exhaust device (5) through a pipeline, and the pipeline passes through the side wall of the closed furnace body (7) and is connected to an exhaust hood (9) in the deposition chamber, and an automatic pressure regulating valve (6) is installed on the pipeline; A lifting and rotating device (8) is installed on the top of the closed furnace body (7), and a loose body (4) is connected to the bottom of the lifting and rotating device (8).

2. The device for producing high-quality synthetic quartz blank according to claim 1, characterized in that: The lifting and rotating device (8) comprises a first motor (801), a connecting plate (802), a second motor (803), an electric telescopic rod (804), a deposition guide rod connector (805), a target rod (806), and a deposition guide rod (807); the main shaft of the first motor (801) is fixedly connected to the electric telescopic rod (804) and the second motor (803) installed on the electric telescopic rod (804) through the connecting plate (802); the telescopic end of the electric telescopic rod (804) is connected to the deposition guide rod (807); and the deposition guide rod (807) is connected to the target rod (806) through the deposition guide rod connector (805).

3. The device for producing high-quality synthetic quartz blank according to claim 1, characterized in that: The number of the raw material burners (1) and the auxiliary burners (2) is several, and the raw material burners (1) and the auxiliary burners (2) are both mounted on the closed furnace body (7) by means of bolts.

4. The device for producing high-quality synthetic quartz blank according to claim 1, characterized in that: The air inlet device (3) is in communication with the closed furnace body (7), and a fan is installed inside the air inlet device (3).

5. The device for producing high-quality synthetic quartz blank according to claim 1, characterized in that: The exhaust hood (9) is arc-shaped, and is connected to the exhaust device (5) through a pipeline. A fan is installed in the exhaust device (5). The exhaust hood (9) is installed on the side wall of the closed furnace body (7) through bolts.

6. The device for producing high-quality synthetic quartz blank according to claim 1, characterized in that: The air inlet device (3), the air exhaust device (5) and the lifting and rotating device (8) are all electrically connected to an external control switch.

7. A process for producing high-quality synthetic quartz blanks, characterized in that: The method is implemented by using the device described in any one of claims 1 to 6, and the specific steps are as follows: Step 1: Check the cleanliness of the deposition chamber in the closed furnace body (7), install the target rod (806) on the deposition guide rod connector (805), start the first motor (801) to rotate, and check the wobble of the target rod (806). The rotation speed is required to be set in the range of 1rpm-60rpm, and the radial wobble of the target rod (806) is ≤1mm; Step 2: The raw material burner (1) and the auxiliary burner (2) preheat the deposition chamber and the target rod (806), and the amount of hydrogen and oxygen in the burner is gradually increased. When the temperature of the target rod (806) reaches 800°C-900°C, the raw material burner (1) is introduced with high-purity raw material. The high-purity raw material uses high-purity oxygen as a carrier gas, and the chamber negative pressure value is set. The vacuum pressure of the deposition chamber is controlled to be maintained at -70Pa±2Pa through the exhaust device (5). The second motor (803) on the electric telescopic rod (804) works at a uniform speed, and the speed setting value is 0.6mm / min-1.5mm / min; Step 3: After continuous step 2 for 30 hours of deposition, a loose body with a size of φ500mm*1500mm is obtained; Step 4: The loose body obtained in step 3 is subjected to vitrification sintering treatment to obtain a product with a typical value of 90% caliber uniformity of <2ppm.

8. The process for producing high-quality synthetic quartz blank according to claim 7, characterized in that: The high-purity raw material in step 2 is SiCl4 or polysiloxane, and the purity of the carrier gas is 9N grade.

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