阅读说明：本技术 石英坩埚制备装置及降低石英坩埚中脱羟的方法 (Quartz crucible preparation device and method for reducing dehydroxylation in quartz crucible ) 是由 何玉鹏 王建军 邓红 李卫 李常国 于 2021-09-16 设计创作，主要内容包括：一种石英坩埚制备装置,包括密封壳体、水冷模具、石墨坩埚、第一真空泵、第二真空泵、排气组件,石墨坩埚的底部嵌入水冷模具,第一真空泵的入口与水冷模具的内腔连通,在密封壳体的侧壁上方设有第一连接口,在密封壳体的侧壁下方设有第二连接口,排气组件包括三通接头、第一阀门、第二阀门、第三阀门,三通接头的第一接口与第一连接口连接,三通接头的第二接口与第一阀门的入口连接,第一阀门的出口与第二真空泵的入口连接,第二阀门的入口与三通接头的第三接口连接,第三阀门的入口与第二连接口连接,密封壳体和水冷模具设置独立真空,能满足脱羟工艺过程要求,羟基含量可以降低到20～30ppm,还提供了一种降低石英坩埚中脱羟的方法。(A quartz crucible preparation device comprises a sealing shell, a water-cooling mold, a graphite crucible, a first vacuum pump, a second vacuum pump and an exhaust assembly, wherein the water-cooling mold is embedded in the bottom of the graphite crucible, an inlet of the first vacuum pump is communicated with an inner cavity of the water-cooling mold, a first connecting port is arranged above the side wall of the sealing shell, a second connecting port is arranged below the side wall of the sealing shell, the exhaust assembly comprises a three-way joint, a first valve, a second valve and a third valve, a first port of the three-way joint is connected with the first connecting port, a second port of the three-way joint is connected with an inlet of the first valve, an outlet of the first valve is connected with an inlet of the second vacuum pump, an inlet of the second valve is connected with a third port of the three-way joint, an inlet of the third valve is connected with the second connecting port, the sealing shell and the water-cooling mold are provided with independent vacuum, the requirements of a dehydroxylation process can be met, the content of hydroxyl can be reduced to 20-30 ppm, and a method for reducing dehydroxylation in a quartz crucible is also provided.)

1. A quartz crucible preparation device is characterized in that: the vacuum heat pump device comprises a sealing shell, a water-cooling mold, a graphite crucible, a first vacuum pump, a second vacuum pump and an exhaust assembly, wherein the sealing shell is hollow, the water-cooling mold is arranged in the sealing shell, the water-cooling mold is hollow, the top opening of the water-cooling mold is opened, the bottom of the graphite crucible is embedded into the open end of the water-cooling mold, the outer side wall of the graphite crucible is hermetically connected with the inner side wall of the water-cooling mold, air holes are formed in the graphite crucible, an inlet of the first vacuum pump is communicated with the inner cavity of the water-cooling mold, a first connecting port is arranged above the side wall of the sealing shell, a second connecting port is arranged below the side wall of the sealing shell, the exhaust assembly comprises a three-way joint, a first valve, a second valve and a third valve, the first port of the three-way joint is connected with the first connecting port, and the second port of the three-way joint is connected with the inlet of the first valve, the outlet of the first valve is connected with the inlet of the second vacuum pump, the inlet of the second valve is connected with the third interface of the three-way joint, and the inlet of the third valve is connected with the second interface.

2. The quartz crucible preparation apparatus as set forth in claim 1, wherein: the quartz crucible preparation device further comprises a heat insulation plate, and the heat insulation plate is horizontally arranged above the water-cooling mold.

3. The quartz crucible preparation apparatus as set forth in claim 2, wherein: the quartz crucible preparation device further comprises a graphite electrode, the graphite electrode is arranged above the heat insulation plate, an insertion hole is formed in the heat insulation plate, and the lower end of the graphite electrode extends into the insertion hole.

4. The quartz crucible preparation apparatus as set forth in claim 3, wherein: the quartz crucible preparation device further comprises a vent pipe, wherein the inlet of the vent pipe is used for being connected with an air source, and the outlet of the vent pipe is communicated with the inner cavity of the graphite crucible.

5. The quartz crucible preparation apparatus as set forth in claim 4, wherein: the quartz crucible preparation device further comprises an infrared thermometer, and the infrared thermometer is arranged above the heat insulation plate.

6. The quartz crucible preparation apparatus as set forth in claim 5, wherein: the water-cooling mold can rotate along the horizontal direction relative to the sealing shell.

7. The quartz crucible preparation apparatus as set forth in claim 6, wherein: the water-cooling mold can rotate along the vertical direction relative to the sealing shell.

8. A method for reducing dehydroxylation in a quartz crucible, which uses the quartz crucible preparation apparatus of claim 7, comprising the steps of:

step one, molding a quartz sand raw material to the inner wall of a graphite crucible to form the quartz crucible;

step two, arc striking of a graphite electrode heats the quartz crucible, the temperature of the quartz crucible is controlled to be above 1800 ℃, a first vacuum pump is started, the vacuum degree of an inner cavity of a water-cooling mold is kept to be above 0.075Mpa, and the melting time is controlled to be 3-6 minutes, so that a transparent layer is formed on the inner side of the quartz crucible;

controlling the temperature of the quartz crucible to be 1700-1900 ℃, turning off the first vacuum pump, enabling the inner cavity of the water-cooled mold to be at normal pressure, and controlling the melting time to be 4-8 minutes, so that an opaque layer is formed on the outer side of the quartz crucible;

and step four, closing the second valve and the third valve, opening the first valve, respectively starting the first vacuum pump and the second vacuum pump, keeping the vacuum degree of the inner cavity of the sealed shell to be smaller than that of the inner cavity of the water-cooling mold, controlling the vacuum degree of the inner cavity of the water-cooling mold to be 0.04-0.06 MPa, controlling the vacuum degree of the inner cavity of the sealed shell to be 0.03-0.05 MPa, controlling the temperature of the quartz crucible to be 1100-1200 ℃, introducing protective gas into the graphite crucible by using a vent pipe, and controlling the melting time to be 10-20 minutes so as to dehydroxylate the quartz crucible.

9. The method for reducing dehydroxylation in a quartz crucible according to claim 8, wherein: the quartz sand raw material is a natural quartz sand raw material or a high-purity synthetic quartz powder raw material.

10. The method for reducing dehydroxylation in a quartz crucible according to claim 8, wherein: the protective gas is argon.

Technical Field

The invention relates to the technical field of quartz crucible production, in particular to a quartz crucible preparation device and a method for reducing dehydroxylation in a quartz crucible.

Background

At present, the quartz crucible is mainly melted by a high-temperature arc method, the heating mode adopts high-temperature arc heating, and the heating material adopts a graphite electrode with higher purity for heating. Before the quartz crucible is melted, high-purity quartz sand needs to be poured into the inner surface of the rotary graphite crucible with any inclination angle, and the high-purity quartz sand is centrifugally formed. The graphite crucible was then rotated to move the underside of the graphite electrode, concentrically aligned. And then starting a power supply, and rapidly discharging an arc on the graphite electrode above the graphite crucible or on the inner surface of the graphite crucible to heat the high-purity quartz sand on the inner surface of the graphite crucible so as to rapidly melt the high-purity quartz sand into the quartz crucible. The inner side of the fused quartz crucible is a transparent layer, the outer side of the fused quartz crucible is a bubble layer, the transparent layer at the inner side is directly contacted with the silicon liquid, bubbles in the transparent layer are few or almost no, and the reduction of the bubbles can meet the requirements of long-time crucible crystal pulling for multiple rods; the content of gas-liquid inclusion in the transparent layer of the crucible can be reduced, and the oxygen content of the crystal bar is further reduced. The bubble layer is arranged outside the quartz crucible and is a necessary way for transferring heat of the external heater to the inner surface of the silicon liquid in the crystal pulling process, and the existence of the bubble layer can enable the heat radiated to the inner surface of the silicon liquid to be more uniform, thereby being beneficial to crystal pulling.

However, in the prior art, the fluctuation of the hydroxyl groups of the fused quartz crucible is relatively large, and the hydroxyl groups exist in the quartz crucible by loose silicon-oxygen bonds, so that the structure and the physical and chemical properties of the quartz crucible are changed, the viscosity of the quartz crucible is reduced, and the quartz crucible is easy to deform in the crystal pulling process, thereby causing accidents. Meanwhile, loose silicon-oxygen bonds are easy to generate reverse reaction in the crystal pulling process, hydroxyl is diffused out to influence the oxygen content and the air hole occurrence rate of the crystal bar and the resistivity fluctuation of the crystal bar, and meanwhile, the diffusion of the hydroxyl is easy to cause the expansion and the breakage of micro bubbles in the transparent layer of the quartz crucible, and the crystal pulling disconnection is caused under the condition of large quantity. On one hand, hydroxyl in the quartz crucible is influenced by a gas-liquid inclusion in the raw material, and on the other hand, the hydroxyl in the quartz crucible is influenced by the temperature and humidity in the melting environment, so that the molten quartz crucible has large fluctuation of the hydroxyl and is difficult to control and remove.

Disclosure of Invention

In view of the above, it is necessary to provide a quartz crucible preparation apparatus.

There is also a need for a method of reducing dehydroxylation in a quartz crucible.

A quartz crucible preparation device comprises a sealing shell, a water-cooling mold, a graphite crucible, a first vacuum pump, a second vacuum pump and an exhaust assembly, wherein the sealing shell is hollow, the water-cooling mold is arranged in the sealing shell, the water-cooling mold is hollow, the top of the water-cooling mold is opened, the bottom of the graphite crucible is embedded into the open end of the water-cooling mold, the outer side wall of the graphite crucible is hermetically connected with the inner side wall of the water-cooling mold, vent holes are formed in the graphite crucible, the inlet of the first vacuum pump is communicated with the inner cavity of the water-cooling mold, a first connecting port is arranged above the side wall of the sealing shell, a second connecting port is arranged below the side wall of the sealing shell, the exhaust assembly comprises a three-way joint, a first valve, a second valve and a third valve, the first connecting port of the three-way joint is connected with the first connecting port, and the second connecting port of the three-way joint is connected with the inlet of the first valve, the outlet of the first valve is connected with the inlet of the second vacuum pump, the inlet of the second valve is connected with the third interface of the three-way joint, and the inlet of the third valve is connected with the second interface.

Preferably, the quartz crucible preparation device further comprises a heat insulation plate, and the heat insulation plate is horizontally arranged above the water-cooled mold.

Preferably, the quartz crucible preparation device further comprises a graphite electrode, the graphite electrode is arranged above the heat insulation plate, an insertion hole is formed in the heat insulation plate, and the lower end of the graphite electrode extends into the insertion hole.

Preferably, the quartz crucible preparation device further comprises a vent pipe, an inlet of the vent pipe is used for being connected with a gas source, and an outlet of the vent pipe is communicated with the inner cavity of the graphite crucible.

Preferably, the quartz crucible preparation device further comprises an infrared thermometer, and the infrared thermometer is arranged above the heat insulation plate.

Preferably, the water-cooling mold can rotate in the horizontal direction relative to the sealing shell.

Preferably, the water-cooling mold can rotate in the vertical direction relative to the sealing shell.

A method for reducing dehydroxylation in a quartz crucible adopts a quartz crucible preparation device, and comprises the following steps:

step one, molding a quartz sand raw material to the inner wall of a graphite crucible to form the quartz crucible;

step two, arc striking of a graphite electrode heats the quartz crucible, the temperature of the quartz crucible is controlled to be above 1800 ℃, a first vacuum pump is started, the vacuum degree of an inner cavity of a water-cooling mold is kept to be above 0.075Mpa, and the melting time is controlled to be 3-6 minutes, so that a transparent layer is formed on the inner side of the quartz crucible;

controlling the temperature of the quartz crucible to be 1700-1900 ℃, turning off the first vacuum pump, enabling the inner cavity of the water-cooled mold to be at normal pressure, and controlling the melting time to be 4-8 minutes, so that an opaque layer is formed on the outer side of the quartz crucible;

and step four, closing the second valve and the third valve, opening the first valve, respectively starting the first vacuum pump and the second vacuum pump, keeping the vacuum degree of the inner cavity of the sealed shell to be smaller than that of the inner cavity of the water-cooling mold, controlling the vacuum degree of the inner cavity of the water-cooling mold to be 0.04-0.06 MPa, controlling the vacuum degree of the inner cavity of the sealed shell to be 0.03-0.05 MPa, controlling the temperature of the quartz crucible to be 1100-1200 ℃, introducing protective gas into the graphite crucible by using a vent pipe, and controlling the melting time to be 10-20 minutes so as to dehydroxylate the quartz crucible.

Preferably, the quartz sand raw material is a natural quartz sand raw material or a high-purity synthetic quartz powder raw material.

Preferably, the protective gas is argon.

Compared with the prior art, the invention has the beneficial effects that:

the quartz crucible preparation device is suitable for directly removing hydroxyl after vitrification of the quartz crucible, can realize molding and hydroxyl removal of the quartz crucible in one step, saves special hydroxyl removal equipment, and effectively meets the control requirement of a hydroxyl removal process because the sealing shell and the water-cooled mold are respectively provided with independent vacuum, so that the hydroxyl content of the quartz crucible can be reduced to 20-30 ppm, the viscosity of the quartz crucible is improved, and bubble expansion of the quartz crucible in a crystal pulling process is inhibited; the deformation probability of the crucible is reduced, and the quality of the single crystal ingot is improved.

Drawings

FIG. 1 is a schematic structural view of the quartz crucible preparation apparatus.

In the figure: the device comprises a sealed shell 10, a water-cooled mold 20, a graphite crucible 30, a first vacuum pump 40, a second vacuum pump 50, an exhaust assembly 60, a three-way joint 61, a first valve 62, a second valve 63, a third valve 64, a heat insulation plate 70, a graphite electrode 80, a breather pipe 90 and an infrared thermometer 100.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Referring to fig. 1, an embodiment of the present invention provides a quartz crucible manufacturing apparatus, including a sealed housing 10, a water-cooled mold 20, a graphite crucible 30, a first vacuum pump 40, a second vacuum pump 50, and an exhaust assembly 60, wherein the sealed housing 10 is hollow, the water-cooled mold 20 is disposed in the sealed housing 10, the water-cooled mold 20 is hollow, a top of the water-cooled mold 20 is open, a bottom of the graphite crucible 30 is inserted into an open end of the water-cooled mold 20, an outer sidewall of the graphite crucible 30 is hermetically connected to an inner sidewall of the water-cooled mold 20, an inlet of the first vacuum pump 40 is communicated with an inner cavity of the water-cooled mold 20, a first connection port is disposed above the sidewall of the sealed housing 10, a second connection port is disposed below the sidewall of the sealed housing 10, the exhaust assembly 60 includes a three-way joint 61, a first valve 62, a second valve 63, and a third valve 64, the first connection port of the three-way joint 61 is connected to the first connection port, the second port of the three-way joint 61 is connected to the inlet of the first valve 62, the outlet of the first valve 62 is connected to the inlet of the second vacuum pump 50, the inlet of the second valve 63 is connected to the third port of the three-way joint 61, and the inlet of the third valve 64 is connected to the second connection port.

Compared with the prior art, the invention has the beneficial effects that:

the quartz crucible preparation device is suitable for directly removing hydroxyl after vitrification of the quartz crucible, can realize molding and hydroxyl removal of the quartz crucible in one step, saves special hydroxyl removal equipment, and effectively meets the control requirement of a hydroxyl removal process because the sealing shell 10 and the water-cooled mold 20 are respectively provided with independent vacuum, so that the hydroxyl content of the quartz crucible can be reduced to 20-30 ppm, the viscosity of the quartz crucible is improved, and bubble expansion of the quartz crucible in a crystal pulling process is inhibited; the deformation probability of the crucible is reduced, and the quality of the single crystal ingot is improved.

Referring to fig. 1, further, the quartz crucible preparation apparatus further includes a heat shield 70, and the heat shield 70 is horizontally disposed above the water-cooled mold 20.

Referring to fig. 1, further, the quartz crucible preparation apparatus further includes a graphite electrode 80, the graphite electrode 80 being disposed above the heat insulating plate 70, an insertion hole being provided on the heat insulating plate 70, and a lower end of the graphite electrode 80 extending into the insertion hole.

Specifically, the diameter of graphite electrode 80 is 40 ~ 80mm, and the ash content of graphite electrode 80 is less than 5ppm, and the diameter of graphite electrode 80 is 100 ~ 20mm less than the diameter of graphite crucible 30, and graphite electrode 80 specifically is 3, and 1 is vertical to be placed to be located the positive center of heat insulating board 70, 2 slope are placed, are located the both sides of heat insulating board 70, and set up with vertical graphite electrode 80 symmetry of placing.

Referring to fig. 1, further, the quartz crucible preparation device further comprises a vent pipe 90, wherein an inlet of the vent pipe 90 is used for connecting a gas source, and an outlet of the vent pipe 90 is communicated with the inner cavity of the graphite crucible 30.

Specifically, the heat shield 70 is provided with an access hole, the access hole is connected with an outlet of the vent pipe 90, or an outlet of the vent pipe 90 passes through the access hole and extends into the inner cavity of the graphite crucible 30, and the horizontal distance between the access hole and the inner wall of the graphite crucible 30 is less than 100 mm.

Specifically, the two vent pipes 90 or the double-row pipe can ensure the flow rate of the vent and realize the mixed introduction of the gas.

Referring to fig. 1, further, the apparatus for manufacturing a quartz crucible further comprises an infrared thermometer 100, wherein the infrared thermometer 100 is disposed above the thermal insulation plate 70.

Referring to fig. 1, further, the water cooling mold 20 may be rotated in a horizontal direction with respect to the hermetic case 10.

Referring to fig. 1, further, the water cooling mold 20 may be rotated in a vertical direction with respect to the sealing case 10.

The embodiment of the invention also provides a method for reducing dehydroxylation in the quartz crucible, which adopts a quartz crucible preparation device and comprises the following steps:

step one, molding a quartz sand raw material to the inner wall of a graphite crucible 30 to form a quartz crucible;

step two, the graphite electrode 80 is used for arc striking to heat the quartz crucible, the temperature of the quartz crucible is controlled to be above 1800 ℃, the first vacuum pump 40 is started, the vacuum degree of the inner cavity of the water-cooling mold 20 is kept to be above 0.075Mpa, and the melting time is controlled to be 3-6 minutes, so that a transparent layer is formed on the inner side of the quartz crucible;

controlling the temperature of the quartz crucible to be 1700-1900 ℃, turning off the first vacuum pump 40, enabling the inner cavity of the water-cooled mold 20 to be normal pressure, and controlling the melting time to be 4-8 minutes, so that an opaque layer is formed on the outer side of the quartz crucible;

and step four, closing the second valve 63 and the third valve 64, opening the first valve 62, respectively starting the first vacuum pump 40 and the second vacuum pump 50, keeping the vacuum degree of the inner cavity of the sealed shell 10 smaller than that of the inner cavity of the water-cooled mold 20, keeping the vacuum degree of the inner cavity of the water-cooled mold 20 at 0.04-0.06 MPa, keeping the vacuum degree of the inner cavity of the sealed shell 10 at 0.03-0.05 MPa, controlling the temperature of the quartz crucible at 1100-1200 ℃, introducing protective gas into the graphite crucible 30 by using the vent pipe 90, and controlling the melting time at 10-20 minutes to dehydroxylize the quartz crucible.

It should be explained that the first vacuum pump 40 is used for evacuating the inner cavity of the water-cooled mold 20, and the inner cavity of the water-cooled mold 20 is a sealed space surrounded by the outer wall of the quartz crucible and the inner wall of the water-cooled mold 20; the second vacuum pump 50 is used for evacuating the inner cavity of the sealed housing 10, and the inner cavity of the sealed housing 10 is a sealed space surrounded by the inner wall of the sealed housing 10, the outer wall of the water-cooled mold 20, and the outer wall of the quartz crucible.

In the second step, after the graphite electrode 80 is ignited to heat the quartz crucible, the quartz crucible is melted quickly, and the melted quartz crucible is not permeable to gas, particularly, the quartz crucible is not permeable to gas when a transparent layer is formed or an opaque layer is formed.

In the second step, the inner cavity of the water-cooled mold 20 is quickly and highly heated to reach the predetermined vacuum degree.

In the second step, the first valve 62 is closed, the second valve 63 and the third valve 64 are opened, and the exhaust fan is started to ventilate the inner cavity of the sealed shell 10, so as to exhaust quartz vapor, electrode dust and the like in the inner cavity of the sealed shell 10.

Utilize the horizontal direction of motor drive water-cooling mould 20 to rotate, water-cooling mould 20 drives graphite crucible 30 horizontal rotation, utilize the vertical direction of motor drive water-cooling mould 20 to rotate, water-cooling mould 20 drives graphite crucible 30 and rotates perpendicularly for graphite crucible 30 inclines, pack into the quartz sand raw materials, the quartz sand raw materials is shaping to graphite crucible 30 inner wall under the effect of centrifugal force, then resume graphite crucible 30 to initial position, make it be under heat insulating board 70, and make the axis of graphite crucible 30 and the axis collineation of the patchhole at heat insulating board 70 center.

Referring to fig. 1, further, the quartz sand raw material is a natural quartz sand raw material or a high-purity synthetic quartz powder raw material.

Referring to fig. 1, further, the shielding gas is argon.

The raw materials of the formed quartz sand are all natural quartz sand raw materials, or the inner layer is high-purity synthetic quartz powder raw materials, and the outer layer is natural quartz sand raw materials.

The hydroxyl content of the quartz crucible produced by the method can be reduced to 20-30 ppm, the bubble level of the quartz crucible can be well controlled, and the quartz crucible can be normally pulled for about 250 hours and still obtain a good bubble level.

The steps in the method of the embodiment of the invention can be sequentially adjusted, combined and deleted according to actual needs.

The modules or units in the device of the embodiment of the invention can be combined, divided and deleted according to actual needs.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.