CN213476159U

CN213476159U - Silicon carbide corrosion furnace body and silicon carbide corrosion furnace

Info

Publication number: CN213476159U
Application number: CN202021965426.8U
Authority: CN
Inventors: 崔孟华; 蔡凯; 王军; 周维
Original assignee: BYD Co Ltd; Shaoguan BYD Electronics Co Ltd
Current assignee: BYD Co Ltd; Shaoguan BYD Electronics Co Ltd
Priority date: 2020-09-09
Filing date: 2020-09-09
Publication date: 2021-06-18
Anticipated expiration: 2030-09-09

Abstract

The utility model belongs to the technical field of semiconductor equipment, especially, relate to a carborundum corrosion furnace body and carborundum corrosion furnace, this carborundum corrosion furnace body includes shell, insulating layer, heating device and crucible, the shell is the ascending tubular structure of opening, the upper portion opening part of shell is provided with the flange that extends to the inboard, the crucible include the ascending crucible main part that just is the tube-shape of opening and by the turn-ups of the outside extension of upper portion opening of crucible main part, the insulating layer parcel the crucible main part, turn-ups and flange are all attached on the up end of insulating layer, the gap has between the inboard edge of turn-ups outside edge and flange. The utility model provides a carborundum corrodes stove furnace body and carborundum corrodes stove, the insulating layer only has the up end to expose through a narrow and small gap, wholly seals in the space between shell and crucible, thoroughly blocks KOH steam corrosion insulating layer, has increased carborundum corrodes stove's life.

Description

Silicon carbide corrosion furnace body and silicon carbide corrosion furnace

Technical Field

The utility model belongs to the technical field of semiconductor equipment, especially, relate to a carborundum corrosion furnace body and carborundum corrosion furnace.

Background

Silicon carbide (SiC) is a typical third-generation wide band gap semiconductor, and has been widely studied and applied to the fields of high temperature, high frequency, high power, radiation resistance, and the like due to its high saturated electron drift rate, high breakdown field strength, high thermal conductivity, and the like. Currently, the most mature technology for commercially producing silicon carbide substrates is Physical Vapor Transport (PVT) Method. The difficulty of growing SiC single crystals by the PVT method lies in controlling the crystal quality, and the defects can be used for subsequent device preparation only when reaching a certain level. The characterization of the quality of the SiC crystal is always an important research subject, because the method not only evaluates the quality of the crystal, but also provides important feedback for a crystal growing process, provides important basis for researching a growth mechanism and analyzing the failure of a device, and has very important significance for basic research and industrial production.

The most classical and accurate method for characterization of crystal quality is chemical etching. SiC is an inert compound and the etching solution is usually a molten base, such as KOH. The basic principle is that the stress is larger at the defect place of the crystal, so the corrosion speed is faster than that of the defect-free place, so the corrosion pit is formed, and different dislocations can form the corrosion pits with different shapes and sizes. The etch pits were then counted by optical microscopy to determine the density of the various defects. However, the alkaline melt used in this technique is volatile at high temperature, and invades and corrodes the heat insulating material in the furnace body, causing the furnace body shell to be conductive, generating the risk of electric shock, and seriously affecting the service life of the corrosion furnace. In addition, the more uniform the thermal field generated by the corrosion furnace, the more accurate the characterization of crystal defects.

For example, a silicon carbide etching furnace disclosed in CN102607923A has a cylindrical furnace body, and a cover is added above a crucible to suppress the overflow of KOH vapor and prevent the damage to the laboratory staff. The thermocouple shell is made of nickel material and can be directly placed in experimental liquid to read temperature data.

However, the above silicon carbide etching furnace still has the following disadvantages:

(1) the furnace body is a cylinder, and the thermocouple is located around the lateral wall, will probably cause the inhomogeneous thermal field that the low marginal temperature of intermediate temperature is high, is unfavorable for the accurate characterization of defect.

(2) The furnace cover is of a horizontal split structure, is opened and closed in the horizontal direction along the fixed shaft and is used for preventing corrosive agent steam from volatilizing to harm human health, but the alkaline fused mass volatilizes at high temperature to generate KOH steam to invade and corrode heat insulation materials in the furnace body, so that the shell of the furnace body is conductive, electric shock risks are generated, and the service life of the corrosion furnace is seriously influenced.

(3) Because the cover needs to be opened as little as possible, the sample needs to be put in advance before being heated, the sample is corroded to a certain extent in the temperature rising process, the corrosion condition is difficult to accurately control, and the method is not reasonable and stable compared with the scheme that the sample is put in after the temperature is raised to a specific temperature.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the technical problem that will solve is: aiming at the problem that KOH steam generated by volatilization of an alkaline molten body at high temperature enters and corrodes heat insulation materials in the furnace body in the existing silicon carbide corrosion furnace, a silicon carbide corrosion furnace body and a silicon carbide corrosion furnace are provided.

In order to solve the technical problem, on the one hand, the embodiment of the utility model provides a carborundum corrosion furnace body, including shell, insulating layer, heating device and crucible, the shell is the ascending tubular structure of opening, the upper portion opening part of shell is provided with the flange that extends to the inboard, the crucible include the ascending crucible main part that just is the tube-shape of opening and by the turn-ups of the outside extension of upper portion opening of crucible main part, insulating layer and crucible main part set up in the shell, the insulating layer parcel the crucible main part, heating device centers on the crucible main part sets up, turn-ups and flange are all attached on the up end of insulating layer, the gap has between the inboard edge of turn-ups outside edge and flange.

Optionally, the lower end face of the thermal insulation layer abuts against the bottom wall of the housing.

Optionally, the heating device is a plurality of heating tubes embedded in the thermal insulation layer, and the plurality of heating tubes are arranged around the outer periphery and the bottom of the crucible main body.

Optionally, the outer shell is a cuboid tubular structure, and the crucible body is a flat cuboid tubular structure.

On the other hand, the embodiment of the utility model provides a carborundum corrosion furnace, including hanging flower basket, elevating gear and foretell carborundum corrosion furnace body;

the hanging basket is used for loading a sample to be corroded, and the lifting device is used for placing the hanging basket into the crucible and lifting the hanging basket out of the crucible.

Optionally, the lifting device comprises a motor, a lifting wire, a support frame and a plurality of pulleys, the pulleys are rotatably mounted on the support frame, the lifting wire is wound on the pulleys, one end of the lifting wire is connected to an output shaft of the motor, the other end of the lifting wire is connected to a hanging ring, a lifting wire with a lifting hook is arranged on the upper portion of the hanging ring, and the lifting hook is hooked on the hanging ring.

Optionally, the support frame comprises a vertical rod and a transverse rod vertically connected to the top end of the vertical rod, and the transverse rod is located above the silicon carbide corrosion furnace body;

the silicon carbide corrosion furnace also comprises a vertical support rod, the top end of the support rod is fixed at one end of the transverse rod, the bottom end of the support rod is fixed on a shell of the motor, and the support rod is provided with scales;

the pulleys are provided with three, two of the pulleys are rotatably mounted on the transverse rod, and the other pulley is rotatably mounted on the supporting rod.

Optionally, the silicon carbide etching furnace further comprises a preheating cavity arranged above the furnace body and used for preheating a sample to be etched, a preheating channel penetrating through the upper end and the lower end of the preheating cavity is arranged inside the preheating cavity, and the lower end of the preheating channel is communicated with the upper opening of the crucible.

Optionally, the preheating cavity is of a cuboid structure with the same size as the cross section of the upper end of the silicon carbide corrosion furnace body, the height of the preheating cavity is 5-20cm, and the size of the preheating channel is the same as that of the upper opening of the crucible main body.

Optionally, the silicon carbide etching furnace further comprises an anti-overflow device arranged above the preheating cavity;

the anti-overflow device comprises a steam adsorption cavity, a pipeline and a water pipe, wherein the bottom of the steam adsorption cavity is provided with an air hole communicated with the inner cavity of the steam adsorption cavity, the side wall of the steam adsorption cavity is provided with a pipe joint communicated with the inner cavity of the steam adsorption cavity, one end of the pipeline is connected to the pipe joint, the other end of the pipeline is connected to the side wall of the water pipe through a switching valve, and the water pipe is connected with a water supply device;

the steam adsorption cavity is provided with a groove channel which is communicated up and down, and the groove channel is used for hoisting a suspension wire of the hanging basket.

According to the utility model discloses carborundum corrosion furnace body and carborundum corrosion furnace, shell are the ascending tubular structure of opening, and the upper portion opening part of shell is provided with the flange that extends to the inboard, and the crucible includes that the opening is ascending and be the crucible main part of tube-shape and by the turn-ups of the outside extension of the upper portion opening of crucible main part, and turn-ups and flange are all attached on the up end of insulating layer. Therefore, only the upper end surface of the heat insulation layer is exposed through a narrow gap and is integrally sealed in the space between the shell and the crucible, KOH steam is thoroughly blocked from corroding the heat insulation layer, and the service life of the silicon carbide corrosion furnace is prolonged. And the shell is not connected with the crucible, and the heat insulation layer is insulated, so that the shell is safe even if the crucible is electrified, and the safety problems of electric leakage and the like are avoided.

Drawings

Fig. 1 is a schematic view of a silicon carbide etching furnace according to an embodiment of the present invention.

The reference numerals in the specification are as follows:

1. a housing; 101. a flange; 2. a thermal insulation layer; 3. heating a tube; 4. preheating the cavity; 5. a preheating channel; 6. a vapor adsorption chamber; 7. a groove channel; 8. air holes; 9. a pipeline; 11. a pulley; 12. hoisting wires; 13. hanging a ring; 14. a support bar; 15. a motor; 16. a crucible; 161. a crucible main body; 162. flanging; 17. a hanging basket; 18. a support frame; 181. a vertical rod; 182. a transverse bar; 19. hanging wires; 20. a water pipe.

Detailed Description

In order to make the technical problem, technical solution and advantageous effects solved by the present invention more clearly understood, the following description is given in conjunction with the accompanying drawings and embodiments to illustrate the present invention in further detail. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in FIG. 1, the embodiment of the present invention provides a silicon carbide etching furnace, which comprises a hanging basket 17, a lifting device and a silicon carbide etching furnace body.

The silicon carbide corrosion furnace body comprises a shell 1, a heat insulation layer 2, a heating device and a crucible 16, wherein the shell 1 is of a cylindrical structure with an upward opening, the upper opening of the shell is provided with a flange 101 extending towards the inner side, the crucible 16 comprises a crucible main body 161 with an upward opening and a flange 162 extending outwards from the upper opening of the crucible main body 161, the heat insulation layer 2 and the crucible main body 161 are arranged in the shell 1, the heat insulation layer 2 wraps the crucible main body 161, the heating device surrounds the crucible main body 161, the flange 161 and the flange 101 are both attached to the upper end face of the heat insulation layer 2, a gap is formed between the outer edge of the flange 161 and the inner edge of the flange 101, and the shell 1 is not communicated with the crucible 16.

The basket 17 is used for loading a sample to be corroded, and the lifting device is used for placing the basket 17 into the crucible 16 and lifting the basket 17 out of the crucible 16.

In one embodiment, the lower end surface of the thermal insulation layer 2 abuts against the bottom wall of the housing 1.

In one embodiment, the heating device is a plurality of heating pipes 3 embedded in the thermal insulation layer 2, and the plurality of heating pipes 3 are arranged around the outer periphery and the bottom of the crucible main body 161. Part of the heating pipe 3 surrounds the crucible main body 161 and is uniformly distributed on the periphery of the crucible main body 161, and part of the heating pipe 3 is arranged at the bottom of the crucible main body 161, so that the temperature in all directions can be kept balanced, and the heating is more uniform. The heating pipes 3 are all positioned in an insulating heat-insulating layer and are not in contact with the shell 1 and the crucible 16, so that electric leakage is avoided.

Heating device adopts heating pipe 3 to inside embedding insulating layer 2, both guaranteed that heating efficiency and temperature measurement are accurate, prevented the risk of electric leakage again, ensured experimenter's safety. The shell 1 can be used for electric leakage protection, and the safety of experimenters is further ensured.

In one embodiment, the housing 1 has a rectangular parallelepiped cylindrical structure. Preferably, the housing 1 is made of stainless steel. The heat insulation layer 2 is made of mullite fiber heat insulation material.

In one embodiment, the crucible body 161 is a flat rectangular parallelepiped tubular structure. Preferably, the material of the crucible 16 is metallic nickel.

Since the sample to be corroded is generally a circular thin sheet, the sample is vertical when being heated (i.e. the diameter of the sample is in the height direction of the furnace body), in order to improve the heating efficiency, the hanging basket 17 is arranged in a rectangular parallelepiped shape, correspondingly, the crucible main body 161 is made of metallic nickel material into a flat rectangular parallelepiped structure, and the outer shell 1 is also preferably made of a rectangular parallelepiped cylindrical structure according to the shape of the crucible 16. The design makes the thermal field more uniform, and the area of the upper opening of the shell 1 is small, thereby reducing the overflow of KOH steam.

In one embodiment, the lifting device comprises a motor 15, a suspension wire 12, a support frame 18 and a plurality of pulleys 11, wherein the plurality of pulleys 11 are rotatably mounted on the support frame 18, the suspension wire 12 is wound on the plurality of pulleys 11, one end of the suspension wire 12 is connected to an output shaft of the motor 15, the other end of the suspension wire 12 is connected with a hanging ring 13, a suspension wire 19 with a suspension hook is arranged on the hanging ring 13, and the suspension hook is hung on the hanging ring 13 to connect the hanging ring 17 to the other end of the suspension wire 12. The motor 15 realizes the lifting of the hanging basket 17 by winding and unwinding the hanging wires 12 so as to immerse the sample to be corroded into the molten KOH in the crucible for corrosion.

The basket 17 is a cuboid and can be loaded with a plurality of samples, including half-pieces and whole-pieces.

In one embodiment, the

suspension wires

12 and 19 can be nickel wires. The hanging basket 17 can be a rectangular hollow structure woven by nickel wires. The basket 17 can hold two four-inch wafers (samples to be etched) simultaneously.

In one embodiment, the supporting frame 18 comprises a vertical rod 181 and a top transverse rod 182 vertically connected to the vertical rod 181, wherein the transverse rod 182 is located above the silicon carbide etching furnace body.

In an embodiment, the silicon carbide etching furnace further comprises a vertical support rod 14, the top end of the support rod 14 is fixed at one end of the transverse rod 182, the bottom end of the support rod 14 is fixed on the housing of the motor 15, and the support rod 14 is provided with scales. The scales on the support rod 14 facilitate accurate control of the depth of immersion of the sample.

In one embodiment, three pulleys 11 are provided, two of the pulleys 11 are rotatably mounted on the transverse bar 182, and the other pulley 11 is rotatably mounted on the support bar 14. The two pulleys 11 on the transverse bar 182 are perpendicular to the pulley plane of the pulleys 11 on the support bar 14.

In an embodiment, the silicon carbide etching furnace further comprises a preheating cavity 4 arranged above the furnace body and used for preheating a sample to be etched, a preheating channel 5 penetrating through the upper end and the lower end of the preheating cavity 4 is arranged inside the preheating cavity 4, and the lower end of the preheating channel 5 is communicated with an upper opening of the crucible 16. The sample is preheated in the preheating channel 5 for a period of time before being heated or taken out, and then is immersed into the molten liquid downwards, so that the sample is prevented from cracking due to sudden heating or quenching.

In an embodiment, the preheating chamber 4 is a rectangular parallelepiped structure having the same size as the cross section of the upper end of the silicon carbide etching furnace body, the height of the preheating chamber 4 is 5-20cm (for example, 10cm), and the size of the preheating channel 5 is the same as the size of the upper opening of the crucible main body 161. The height of the preheating chamber 4 is selected to match the size of the sample, the sample is usually a circular thin sheet, and the sample is vertical (i.e. the diameter is in the height direction) when being heated, so that the height of the preheating chamber 4 is larger than the diameter of the sample, so as to be capable of sufficiently and rapidly preheating the sample.

In one embodiment, the silicon carbide etching furnace further comprises an overflow preventing device arranged above the preheating cavity. The anti-overflow device comprises a steam adsorption cavity 6, a pipeline 9 and a water pipe 20, wherein the bottom of the steam adsorption cavity 6 is provided with an air hole 8 communicated with the inner cavity of the steam adsorption cavity 6, the side wall of the steam adsorption cavity 6 is provided with a pipe joint communicated with the inner cavity of the steam adsorption cavity 6, one end of the pipeline 9 is connected to the pipe joint, the other end of the pipeline 9 is connected to the side wall of the water pipe 20 through a switching valve, and the water pipe 20 is connected with a water supply device.

In fig. 1, the water supply device is a faucet. However, the water supply device may be a water tank with a water pump or the like.

The steam adsorption cavity 6 is provided with a groove channel 7 which is communicated up and down, and the groove channel 7 is used for hoisting a suspension wire 19 of the hanging basket 17.

In one embodiment, the vapor adsorption chamber 6 is a triangular prism chamber. The triangular prism cavity has a gradually reduced section from bottom to top, which is beneficial for KOH steam to be focused on the upper part of the steam adsorption cavity 6 and then discharged.

When the corrosion furnace is used, the water tap is opened, water flows in the water pipe 20, and steam in the steam adsorption cavity 6 is sucked away through the pressure difference generated by the water flow and is discharged through the water flow. Thereby preventing the escape of KOH vapor. Compared with the capping sealing adopted in the prior art, the sealing device is safer and more effective, and does not influence the operation.

According to the utility model discloses carborundum corrosion furnace body and carborundum corrosion furnace, the crucible includes that the opening upwards just is the crucible main part of tube-shape and by the turn-ups of the outside extension of upper portion opening of crucible main part, turn-ups outward flange overlap joint at the upper portion opening part of shell to form airtight space between shell and crucible, the insulating layer setting is in airtight space, heating device centers on the crucible setting. Thus, the heat insulating layer is enclosed in a closed space formed between the outer shell and the crucible, and KOH vapor is thoroughly blocked from corroding the heat insulating layer. The safety problems of electric leakage and the like are avoided, and the service life of the silicon carbide corrosion furnace is prolonged.

The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims

1. The utility model provides a carborundum corrosion furnace body, its characterized in that, includes shell, insulating layer, heating device and crucible, the shell is the ascending tubular structure of opening, the upper portion opening part of shell is provided with the flange that extends to the inboard, the crucible include the ascending crucible main part that just is the tube-shape of opening and by the turn-ups of the outside extension of upper portion opening of crucible main part, insulating layer and crucible main part set up in the shell, the insulating layer parcel the crucible main part, heating device centers on the crucible main part sets up, turn-ups and flange are all attached on the up end of insulating layer, the gap has between the inboard edge of turn-ups's outside edge and flange.

2. The silicon carbide corrosion furnace body of claim 1, wherein the lower end surface of the thermal insulation layer abuts against the bottom wall of the outer shell.

3. The silicon carbide corrosion furnace body of claim 1, wherein the heating device is a plurality of heating tubes embedded in the thermal insulation layer, the plurality of heating tubes being disposed around the outer periphery and bottom of the crucible body.

4. The silicon carbide corrosion furnace body of claim 1, wherein the outer shell is a rectangular parallelepiped tubular structure and the crucible body is a flat rectangular parallelepiped tubular structure.

5. A silicon carbide corrosion furnace is characterized by comprising a hanging basket, a lifting device and the silicon carbide corrosion furnace body of any one of claims 1 to 4;

6. The silicon carbide etching furnace of claim 5, wherein the lifting device comprises a motor, a suspension wire, a support frame and a plurality of pulleys, the plurality of pulleys are rotatably mounted on the support frame, the suspension wire is wound on the plurality of pulleys, one end of the suspension wire is connected to an output shaft of the motor, the other end of the suspension wire is connected with a hanging ring, a suspension wire with a suspension hook is arranged on the upper portion of the hanging ring, and the suspension hook is hung on the hanging ring.

7. The silicon carbide corrosion furnace of claim 6, wherein the support frame comprises a vertical rod and a transverse rod vertically connected to the top end of the vertical rod, and the transverse rod is positioned above the silicon carbide corrosion furnace body;

8. The silicon carbide etching furnace of claim 5, further comprising a preheating cavity arranged above the furnace body for preheating a sample to be etched, wherein a preheating channel penetrating through the preheating cavity is arranged inside the preheating cavity, and the lower end of the preheating channel is communicated with the upper opening of the crucible.

9. The silicon carbide corrosion furnace of claim 8, wherein the preheating cavity is a rectangular parallelepiped structure having the same size as the upper end cross section of the silicon carbide corrosion furnace body, the height of the preheating cavity is 5-20cm, and the size of the preheating channel is the same as that of the upper opening of the crucible main body.

10. The silicon carbide etching furnace of claim 8, further comprising an overflow prevention device disposed above the preheating chamber;