Sintering and groove sinking integrated system for preparing photomask quartz substrate

Abstract

The sintering and groove sinking integrated system comprises a sintering furnace, a groove sinking furnace, a weighing mechanism, a driving mechanism and a groove sinking mold, the weighing mechanism is connected with the driving mechanism, the driving mechanism is connected with a quartz rod, the bottom end of the sintering furnace is connected with the top end of the groove sinking furnace, and inner cavities of the sintering furnace and the groove sinking furnace are communicated. And the groove sinking die is arranged in the groove sinking furnace. According to the utility model, the sintering furnace and the groove sinking furnace are integrally arranged, and a quartz rod is directly subjected to groove sinking shaping after being sintered, so that the production time is effectively shortened, and the production cost is reduced; a driving mechanism is used for hanging and driving a quartz rod to descend, the quartz rod enters a groove sinking furnace after being densified in a sintering area, and the quartz rod is gradually melted and spread in a groove sinking mold from the bottom, so that the problems of stripes, bubbles, poor uniformity and large stress in a product caused by folding and toppling due to the fact that the length-diameter ratio of the quartz rod is too large are solved; production of large-size, low-defect, high-performance and high-purity products is achieved, and the method can be applied to development of IC photomask substrates.

Description

Technical Field

[0001] The utility model relates to the technical field of quartz substrate preparation, in particular to a sintering tank sink integrated system for preparing a photomask quartz substrate. Background Art

[0002] Quartz glass, an amorphous material composed solely of silicon dioxide, is a specialty industrial technical glass characterized by its low thermal expansion coefficient, high temperature and thermal shock resistance, chemical stability, and excellent electrical insulation. It is also transparent to ultraviolet and infrared light and is widely used in the manufacture of semiconductors, electro-optical sources, semiconductor communication devices, lasers, and optical instruments. Quartz glass substrates for semiconductor photomasks offer optimal chemical stability, high hardness, low thermal expansion coefficient, and high light transmittance, making them suitable for the production of products requiring high precision and widely used in IC photomasks.

[0003] Synthetic quartz has excellent optical properties such as high purity, high transmittance, good uniformity, low stress, no streaks, no particle structure, no bubbles, no inclusions, no fluorescence, and resistance to laser damage. It also has excellent thermal, electrical, mechanical and chemical properties. It is the key material selected for 193nm band lithography systems. The requirements for lithography-grade quartz materials are extremely high. Its optical uniformity alone needs to be within 1.0×10 -6 In the past few years, the requirements for the uniformity and transmittance of quartz materials have become increasingly higher, which means that the requirements for the preparation of quartz blanks are also becoming more and more stringent.

[0004] There are currently many quartz glass production processes, one of which is the VAD (vacuum arc degassing) method for synthesizing quartz. VAD is an indirect synthesis method with the following process characteristics: high deposition efficiency, fast rate, low hydroxyl content, and this method is a vapor deposition method with a simple process route. The raw materials are SiCl4, hydrogen and oxygen, which are widely available and low in cost.

[0005] Quartz products produced by the VAD method have extremely low impurity content and have the significant advantages of high resistance to laser damage, high optical uniformity, and low absorption coefficient. However, due to size issues, their application scenarios are limited. To meet the needs of various applications, the quartz rod materials deposited by the VAD method usually need to undergo groove sinking modification to reach specific application sizes. Groove sinking is to achieve the purpose of secondary molding by softening the quartz glass at high temperature. However, due to the large aspect ratio of quartz rods produced by the VAD method, they are prone to tipping and folding during the glass softening stage during groove sinking, resulting in problems such as bubbles, streaks, high stress, and poor uniformity in the product. In severe cases, it can cause damage to the graphite mold, resulting in material waste and increased costs.

[0006] Optical uniformity is an important indicator for measuring the optical quality of quartz glass. It indicates the degree of uniformity of the refractive index within an isotropic medium. When light passes through an inhomogeneous medium, the wavefront will be distorted. The magnitude of the distortion depends on the product of the refractive index difference and the thickness. This reduces the resolution and imaging quality, which will cause the optical system to fail to achieve the expected function or even fail to work properly. Stress birefringence is another important indicator for measuring optical quartz glass. Its main effects are: (1) the processing process can easily cause the material to break and break, (2) during precision processing, stress is continuously released, which can easily cause problems with the processing surface shape, and (3) when a polarized light system is used, it causes a decrease in the quality of the optical system. Utility Model Content

[0007] The technical problem to be solved by the utility model is to provide a sintering and slot sinking integrated system for preparing a photomask quartz substrate. A sintering-slot sinking integrated system is developed, in which a VAD-deposited quartz rod is driven by a driving mechanism to gradually descend, and after sintering and densification in a sintering furnace, it gradually descends to a slot sinking furnace. The quartz rod is gradually subjected to high temperature from bottom to top to form molten quartz and spread out in a slot sinking mold. The quartz substrate after slot sinking has excellent performance, and avoids the VAD-deposited quartz rod being easily folded and tipped over during slot sinking due to an excessively large aspect ratio, thereby causing the product to be prone to stripes, bubbles, poor uniformity and high stress.

[0008] In order to solve the above technical problems, the utility model provides a sintering tank sink integrated system for preparing a photomask quartz substrate, comprising a sintering furnace, a tank sink furnace, a weighing mechanism, a driving mechanism and a tank sink mold;

[0009] The weighing mechanism is connected to the driving mechanism, the driving mechanism is connected to the quartz rod, and the weighing mechanism, the driving mechanism and the quartz rod are vertically arranged in sequence from top to bottom and are located directly above the sintering furnace;

[0010] The bottom end of the sintering furnace is connected to the top end of the trough sink furnace, and the internal cavities of the two are connected;

[0011] The groove sinking mold is arranged in the groove sinking furnace, and the groove sinking mold is located directly below the quartz rod.

[0012] The utility model combines the sintering process after the VAD process with the trough sinking process, and integrates the sintering furnace and the trough sinking furnace into an integrated arrangement. The quartz rod deposited by the VAD is driven downward by a driving mechanism, and after being sintered and densified in the sintering zone of the sintering furnace, it continues to descend to the trough sinking furnace. The bottom to the top of the quartz rod gradually enter the high-temperature trough sinking area of ​​the trough sinking furnace, and after being subjected to high temperature, molten quartz is formed and falls and spreads out in the trough sinking mold. During the process, the quartz rod is suspended by the driving mechanism, and gradually melts and softens from the bottom and falls into the trough sinking mold. The weight change of the quartz rod is detected by the weighing mechanism, and the rate of quartz rod descent is regulated by the driving mechanism, thereby controlling the weight reduction rate of the quartz rod. This avoids the overall melting and softening of the quartz rod, and the problems of folding and tipping due to the large aspect ratio, which in turn causes stripes, bubbles, poor uniformity and stress differences on the quartz substrate.

[0013] Furthermore, the sintering furnace includes a furnace core tube, and the outer circumference of the furnace core tube is sheathed with a first insulation layer, a first heater and a second insulation layer from top to bottom.

[0014] Furthermore, the groove sinking furnace includes a furnace body, a second heater is provided on the outer periphery of the upper portion of the furnace body, and the groove sinking mold is located in an area surrounded by the second heater.

[0015] Furthermore, the furnace core tube is made of high-purity JGS3 quartz material, and the first heater and the second heater are graphite heaters.

[0016] Furthermore, it also includes a supporting platform located in the trough sinking furnace, which is arranged below the trough sinking mold and is used to support the trough sinking mold; a liftable furnace door is provided at the bottom of the trough sinking furnace, and the supporting platform is provided above the furnace door, and the trough sinking mold enters and exits the trough sinking furnace through the liftable furnace door.

[0017] Furthermore, it also includes a PLC module, which is connected to the weighing mechanism and the driving mechanism. When the tank sinks, the weighing mechanism detects the change in product weight and controls the driving mechanism to adjust the descending speed of the quartz rod.

[0018] Furthermore, graphite paper is placed in the groove sinking mold, the thickness of the graphite paper is 0.5-1.0 mm, and the ash content is less than 20 ppm.

[0019] The working method of the sintering tank sink integrated system for preparing a photomask quartz substrate of the utility model comprises the following steps:

[0020] S1. Hang the VAD-deposited quartz rod to the lower end of the driving mechanism, and the driving mechanism drives the bottom end of the quartz rod down to the sintering zone of the sintering furnace;

[0021] S2. The heater of the sintering furnace is started. When the temperature of the sintering zone is raised to 1400-1450°C, the driving mechanism drives the quartz rod to rotate and descend. The quartz rod is sintered and densified in the sintering zone. When the bottom end of the quartz rod descends to the connection between the sintering furnace and the trough sink furnace, the driving mechanism is stopped. The heater of the sintering furnace controls the temperature of the sintering zone to decrease to 750-900°C.

[0022] S3. The heater of the trough sinking furnace is started. When the temperature of the trough sinking area is raised to 1750-1805°C, the driving mechanism drives the quartz rod to gradually descend into the trough sinking furnace. The quartz rod is gradually exposed to the high temperature to form molten quartz from bottom to top and is spread out in the trough sinking mold for sinking. During the sinking process, the weighing mechanism monitors the weight change of the quartz rod in real time.

[0023] S4. When the weighing mechanism detects that the weight of the quartz rod is reduced to 0, the driving mechanism stops, and after standing for 1-4 hours, the driving mechanism starts to rise and reset;

[0024] S5, cooling the tank sink furnace to 1050-1150° C. and annealing at a constant temperature for 24-72 hours, then cooling to room temperature, and obtaining a photomask quartz substrate after fine processing.

[0025] Furthermore, in S1, the descending speed of the quartz rod is 10-400 mm / min.

[0026] Furthermore, in S2, the descending speed of the quartz rod is 0.5-10 mm / min, and the rotating speed is 0.1-10 r / min.

[0027] Furthermore, in S2, the heating time of the sintering furnace is 2-4 hours.

[0028] Furthermore, in S3, the heating time of the trough sinking furnace is 8-10 hours.

[0029] Furthermore, in S3, the weighing mechanism detects the weight change of the quartz rod and adjusts the descending speed of the quartz rod through the PLC linkage control driving mechanism so that the weight reduction rate of the quartz rod is 0.5-5 kg / min.

[0030] Furthermore, in S4, when the weight of the quartz rod is reduced to 0, the head of the quartz rod is just located at the connection between the sintering furnace and the trough sinking furnace. Under the high temperature of the trough sinking furnace, the head of the quartz rod is separated from the effective section due to the influence of gravity.

[0031] Furthermore, in S5, the cooling rate of the trough sinking furnace to 1050-1150°C is 50-200°C / h; the cooling to room temperature is specifically: cooling to 600-700°C at a rate of 3-10°C / h, and then naturally cooling to room temperature.

[0032] Furthermore, in S2, the weighing mechanism detects the weight of the quartz rod to detect whether the quartz rod is broken during the sintering and densification process.

[0033] Beneficial effects of the utility model:

[0034] The utility model integrates the sintering furnace and the groove sinking furnace, and the quartz rods deposited by VAD are directly subjected to groove sinking shaping after sintering, which effectively shortens the production time and reduces the production cost.

[0035] The utility model adopts a driving mechanism to suspend and drive the quartz rod to gradually descend. After being densified in the sintering zone, it gradually enters the trough sink furnace and gradually melts, softens and spreads out in the trough sink mold starting from the bottom, avoiding the problems of folding and tipping due to the large aspect ratio of the quartz rod, which in turn causes stripes, bubbles, poor uniformity and high stress in the product.

[0036] The utility model solves the problem of VAD quartz rods being limited in application due to their size by means of groove sinking modification, and realizes the production of large-size, low-defect, high-performance, and high-purity products, which can be applied to the development of IC photomask substrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic structural diagram of a sintering tank-sink integrated system for preparing a photomask quartz substrate according to the present invention;

[0038] Figure 2 In the figure, a, b, and c are schematic structural diagrams of the sintering, groove sinking, and groove sinking completion states of the sintering groove sinking integrated system for preparing a photomask quartz substrate according to the present invention, respectively;

[0039] Explanation of the numbers in the figure: 1. Weighing mechanism, 2. Driving mechanism, 3. Sinking mold, 4. Quartz rod, 5. Furnace core tube, 6. First insulation layer, 7. First heater, 8. Second insulation layer, 9. Furnace body, 10. Second heater, 11. Support platform, 12. Furnace door. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0041] This embodiment relates to a sintering tank sink integrated system for preparing a photomask quartz substrate, such as Figure 1As shown, the system comprises a sintering furnace, a slot sink furnace, a weighing mechanism 1, a driving mechanism 2, and a slot sink mold 3. The weighing mechanism 1 is connected to the driving mechanism 2, which is connected to a quartz rod 4. The weighing mechanism 1, the driving mechanism 2, and the quartz rod 4 are arranged vertically in order from top to bottom and are located directly above the sintering furnace. The bottom end of the sintering furnace is connected to the top end of the slot sink furnace, and the internal cavities of the two are connected. The slot sink mold 3 is disposed within the slot sink furnace and is located directly below the quartz rod 4. In this embodiment, the integrated sintering and slot sinking system for preparing photomask quartz substrates combines the sintering process after the VAD process with the slot sinking process, integrating the sintering furnace and the slot sink furnace. The VAD-deposited quartz rod 4 undergoes the slot sinking process directly after sintering, improving production efficiency and saving costs.

[0042] In this embodiment, the system suspends the VAD-deposited quartz rod 4 through the driving mechanism 2 and drives the quartz rod 4 to move downward. After sintering and densification in the sintering zone of the sintering furnace, the quartz rod 4 continues to descend to the trough sink furnace. The bottom to the top of the quartz rod 4 gradually enters the high-temperature trough sink area of ​​the trough sink furnace. After high temperature, molten quartz is formed and falls and spreads in the trough sink mold 3. During the process, the quartz rod 4 is suspended by the driving mechanism 2, gradually melts and softens from the bottom, and falls into the trough sink mold 3. The weight change of the quartz rod 4 is detected by the weighing mechanism 1, and the rate of quartz rod 4 descent is regulated by the driving mechanism 2, thereby controlling the weight reduction rate of the quartz rod 4. This avoids the overall melting and softening of the quartz rod 4, which leads to folding and tipping due to the large aspect ratio, and thus causes stripes, bubbles, poor uniformity and stress differences on the quartz substrate.

[0043] Specifically, the sintering furnace includes a furnace core tube 5, the outer periphery of which is sheathed from top to bottom with a first insulation layer 6, a first heater 7, and a second insulation layer 8. The first heater 7 is disposed between the first insulation layer 6 and the second insulation layer 8, and the insulation area of ​​the first heater 7 forms a high-temperature sintering zone. The trough sink furnace includes a furnace body 9, a second heater 10 is disposed on the outer periphery of the upper portion of the furnace body 9, and the trough sink mold 3 is located within the area surrounded by the second heater 10. The second heater is disposed on the upper portion of the furnace body 9, forming a high-temperature trough sink area in the area surrounded by the second heater 10. The furnace core tube 5 is made of high-purity JGS3 quartz material, and the first heater 7 and the second heater 10 are graphite heaters.

[0044] Specifically, it also includes a support platform 11 located in the trough sink furnace, the support platform 11 is arranged below the trough sink mold 3, and is used to support the trough sink mold 3; a liftable furnace door 12 is provided at the bottom of the trough sink furnace, and the support platform 11 is arranged above the furnace door 12, and the trough sink mold 3 enters and exits the trough sink furnace through the liftable furnace door 12. Graphite paper is placed in the trough sink mold 3, and the thickness of the graphite paper is 0.5-1.0mm, and the ash content is less than 20ppm. Specifically, the components of the driving mechanism to achieve the lifting and rotation functions are conventional means, which will not be elaborated here. It is sufficient to achieve the lifting and rotation of the quartz rod, and can be composed of a lifting motor, a rotating motor, and a connecting rod.

[0045] Preferably, a PLC module (not shown in the figure) is further included, which connects the weighing mechanism 1 and the driving mechanism 2. When the tank sinks, the weighing mechanism 1 detects the change in product weight and controls the driving mechanism 2 to adjust the descending speed of the quartz rod 4.

[0046] A working method of the system of this embodiment includes the following steps:

[0047] S1, VAD deposited quartz rod 4 (diameter 320mm, density 0.5g / cm 3 , effective weight 50kg) is hung on the lower end of the driving mechanism 2, and the driving mechanism 2 drives the bottom end of the quartz rod 4 to descend to the sintering zone of the sintering furnace. The descending speed of the quartz rod 4 is 100mm / min, and the weighing system records the weight of the quartz rod 4 in real time;

[0048] S2, the first heater 7 of the sintering furnace is started, the sintering zone is heated to 1430 ° C for 2h, and the driving mechanism 2 drives the quartz rod 4 to rotate and descend, wherein the descending speed of the quartz rod 4 is 1mm / min and the rotating speed is 3r / min. The quartz rod 4 is sintered and densified in the sintering zone, as shown in FIG. Figure 2 As shown in a, when the bottom end of the quartz rod 4 drops to the connection between the sintering furnace and the trough sink furnace, the driving mechanism 2 stops, and the first heater 7 of the sintering furnace controls the sintering zone to cool down to 800°C;

[0049] S3, the second heater 10 of the tank sinking furnace is started, the tank sinking area is heated to 1800℃ for 8h, the driving mechanism 2 drives the quartz rod 4 to gradually descend into the tank sinking furnace, and the quartz rod 4 is gradually formed from the bottom to the top by the high temperature into molten quartz and spread out in the tank sinking mold 3. Figure 2 As shown in Figure b, during the sinking process, the weighing mechanism 1 monitors the weight change of the quartz rod 4 in real time, and adjusts the descending speed of the quartz rod 4 through the PLC linkage control driving mechanism 2 so that the weight reduction rate of the quartz rod 4 is 0.5 kg / min;

[0050] S4, when the weighing mechanism 1 detects that the weight of the quartz rod 4 is reduced to 0, the driving mechanism 2 stops and stands for 2 hours. At this time, the head of the quartz rod 4 is just located at the connection between the sintering furnace and the trough sinking furnace. Under the high temperature of the trough sinking furnace, the head of the quartz rod 4 is separated from the effective section by gravity, and then the driving mechanism 2 starts to rise and reset. Figure 2 As shown in c;

[0051] S5. The tank sink furnace is cooled at a rate of 50°C / h to 1130°C for constant temperature annealing for 48 hours, and then cooled at a rate of 5°C / h to 650°C. After the second heater is turned off, the temperature is naturally cooled to room temperature. The quartz ingot is taken out through the liftable furnace door 12 at the bottom of the tank sink furnace. After fine processing, the quartz ingot is obtained with a size of φ355mm×205mm, a transmittance of 99.6% / cm at 193nm, and an optical non-uniformity of 2×10 - 6 ppm, photomask quartz substrate with stress birefringence of 2 nm / cm.

[0052] Another working method of the system of this embodiment includes the following steps:

[0053] S1, VAD deposited quartz rod 4 (diameter 320mm, density 0.5g / cm 3 , effective weight 45kg) is hung on the lower end of the driving mechanism 2, and the driving mechanism 2 drives the bottom end of the quartz rod 4 to descend to the sintering zone of the sintering furnace. The descending speed of the quartz rod 4 is 200mm / min, and the weighing system records the weight of the quartz rod 4 in real time;

[0054] S2, the first heater 7 of the sintering furnace is started, the sintering zone is heated to 1435 ° C for 2h, and the driving mechanism 2 drives the quartz rod 4 to rotate and descend, wherein the descending speed of the quartz rod 4 is 1.5mm / min and the rotating speed is 3r / min. The quartz rod 4 is sintered and densified in the sintering zone, as shown in FIG. Figure 2 As shown in a, when the bottom end of the quartz rod 4 drops to the connection between the sintering furnace and the trough sink furnace, the driving mechanism 2 stops, and the first heater 7 of the sintering furnace controls the sintering zone to cool down to 850°C;

[0055] S3, the second heater 10 of the tank sinking furnace is started, the tank sinking area is heated to 1780℃ for 8 hours, the driving mechanism 2 drives the quartz rod 4 to gradually descend into the tank sinking furnace, and the quartz rod 4 is gradually formed from the bottom to the top by the high temperature into molten quartz and spread out in the tank sinking mold 3. Figure 2 As shown in Figure b, during the sinking process, the weighing mechanism 1 monitors the weight change of the quartz rod 4 in real time, and adjusts the descending speed of the quartz rod 4 through the PLC linkage control driving mechanism 2 so that the weight reduction rate of the quartz rod 4 is 0.6 kg / min;

[0056] S4, when the weighing mechanism 1 detects that the weight of the quartz rod 4 is reduced to 0, the driving mechanism 2 stops and stands for 2 hours. At this time, the head of the quartz rod 4 is just located at the connection between the sintering furnace and the trough sinking furnace. Under the high temperature of the trough sinking furnace, the head of the quartz rod 4 is separated from the effective section by gravity, and then the driving mechanism 2 starts to rise and reset. Figure 2 As shown in c;

[0057] S5, the tank sink furnace is cooled to 1100°C at a rate of 80°C / h and annealed at a constant temperature for 36 hours, then cooled to 680°C at a rate of 7°C / h, and the second heater is turned off and the temperature is naturally cooled to room temperature. The quartz ingot is taken out through the liftable furnace door 12 at the bottom of the tank sink furnace, and after fine processing, the size is φ345mm×210mm, the transmittance at 193nm is 99.5% / cm, and the optical non-uniformity is 3×10 - 6 ppm, photomask quartz substrate with stress birefringence of 2.3 nm / cm.

[0058] In summary, the utility model integrates the sintering furnace and the slot sink furnace, and the quartz rods deposited by VAD are directly slot-sinked and shaped after sintering, which effectively shortens the production time and reduces production costs. The utility model adopts a driving mechanism to suspend and drive the quartz rod to gradually descend, and gradually enter the slot sink furnace after densification in the sintering zone, and gradually melt and soften from the bottom and spread out in the slot sink mold, avoiding the folding and tipping caused by the large aspect ratio of the quartz rod, which in turn causes stripes, bubbles, poor uniformity and high stress in the product. The utility model solves the problem of limited application of VAD quartz rods due to size by modifying the slot sink, and realizes the production of large-size, low-defect, high-performance and high-purity products, which can be applied to the development of IC photomask substrates.

[0059] The above-described embodiments are merely preferred embodiments for the purpose of fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are within the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

Claims

1. A sintering tank sink integrated system for preparing photomask quartz substrates, characterized in that: It includes a sintering furnace, a trough sinking furnace, a weighing mechanism, a driving mechanism and a trough sinking mold; The weighing mechanism is connected to the driving mechanism, the driving mechanism is connected to the quartz rod, and the weighing mechanism, the driving mechanism and the quartz rod are vertically arranged in sequence from top to bottom and are located directly above the sintering furnace; The bottom end of the sintering furnace is connected to the top end of the trough sink furnace, and the internal cavities of the two are connected; The groove sinking mold is arranged in the groove sinking furnace, and the groove sinking mold is located directly below the quartz rod.

2. The sintering tank sinking integrated system for preparing a photomask quartz substrate according to claim 1, characterized in that: The sintering furnace comprises a furnace core tube, and the outer circumference of the furnace core tube is sheathed with a first thermal insulation layer, a first heater and a second thermal insulation layer from top to bottom.

3. The sintering tank sinking integrated system for preparing a photomask quartz substrate according to claim 1, characterized in that: The groove sinking furnace includes a furnace body, a second heater is arranged on the outer periphery of the upper part of the furnace body, and the groove sinking mold is located in the area surrounded by the second heater.

4. The sintering tank sinking integrated system for preparing a photomask quartz substrate according to claim 1, wherein: It also includes a support platform located in the trough sinking furnace, and the support platform is arranged below the trough sinking mold.

5. The sintering tank sinking integrated system for preparing a photomask quartz substrate according to claim 4, characterized in that: A liftable furnace door is provided at the bottom of the trough sink furnace, and the support platform is provided above the furnace door.

6. The sintering tank sinking integrated system for preparing a photomask quartz substrate according to claim 1, characterized in that: Graphite paper is placed in the groove sinking mold, the thickness of the graphite paper is 0.5-1.0 mm, and the ash content is less than 20 ppm.

7. The sintering tank sinking integrated system for preparing a photomask quartz substrate according to claim 1, characterized in that: It also includes a PLC module, which connects the weighing mechanism and the driving mechanism.

8. The sintering tank sinking integrated system for preparing a photomask quartz substrate according to claim 2, characterized in that: The first heater is a graphite heater.

9. The sintering tank sinking integrated system for preparing a photomask quartz substrate according to claim 2, characterized in that: The furnace core tube is made of quartz material.

10. The sintering tank sinking integrated system for preparing a photomask quartz substrate according to claim 3, characterized in that: The second heater is a graphite heater.

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