Automatic liquid adding type silicon carbide etching equipment

Abstract

The application discloses an automatic liquid adding type silicon carbide etching equipment, which comprises an etching cylinder with a feeding opening at a right end and a cylindrical structure and a bearing frame for bearing silicon carbide wafers, a heater is arranged at the bottom of the etching cylinder, and an outer surface of the heater is provided with a heat preservation shell, and a heating cavity in the heater is communicated with an inner cavity of the etching cylinder through a ventilation opening arranged at the bottom of the inner cavity of the etching cylinder, and the equipment is characterized in that the equipment further comprises a sealing driving unit, an automatic liquid adding unit and an atomizing cleaning and cooling unit. The automatic liquid adding unit of the equipment can automatically add an appropriate amount of alkaline solution according to the number of silicon carbide wafers, manual adding operation is not needed, and the number of placed silicon carbide wafers does not need to be memorized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicon carbide wafer, in particular to an automatic liquid adding type silicon carbide etching equipment. BACKGROUND

[0002] Silicon carbide is one of the third generation semiconductor materials that is most widely studied at present, and has good application prospects in the fields of photovoltaic, new energy vehicles, smart grid, etc. Related research and products are constantly being introduced, and the economic benefits are good, and the application value is high.

[0003] An important problem restricting the application of silicon carbide devices at present is wafer defects. Through the continuous efforts of scientific research and industry, the inclusions, voids, polytypes and other defects of high-quality silicon carbide wafers have been completely eliminated, and microtubules, dislocations and other defects have become the focus of attention. Microtubules can cause direct failure of devices, and dislocations such as edge dislocations, screw dislocations, and basal plane dislocations can reduce carrier lifetime and affect device performance. Therefore, positioning and analyzing such defects have become an important requirement for material preparation and device fabrication.

[0004] Etching is a main means of characterizing silicon carbide defects. By controlling the etching process, one or several defects can be quickly distinguished. High-temperature alkali vapor has good distinguishing effect on silicon carbide etching defects.

[0005] After searching, a Chinese patent document with the authorized publication number CN113550012B and the name "A device for etching silicon carbide wafer by alkali vapor" was found. According to the content in the specification, before etching the silicon carbide wafer, the operator needs to add a certain amount of alkaline solution to the corrosion-resistant boat according to the number of silicon carbide wafers placed. Manual addition is more troublesome, and the specific number of silicon carbide wafers placed needs to be clearly understood at each time of addition to avoid excessive addition of alkaline solution (generally, the number of silicon carbide wafers needs to be confirmed before adding alkaline solution), therefore, the present application provides an alkaline vapor etching silicon carbide wafer equipment to meet the demand, therefore, the present application provides an automatic liquid adding type silicon carbide etching equipment to meet the demand. SUMMARY

[0006] The purpose of the present application is to provide an automatic liquid adding type silicon carbide etching equipment to solve the technical problem of manually adding an appropriate amount of alkaline solution according to the number of silicon carbide wafers placed in the prior art.

[0007] To achieve the above object, the application provides the following technical scheme: an automatic liquid adding type silicon carbide etching equipment, comprising an etching cylinder with a feed opening at a right end and a cylindrical structure, and a bearing frame for bearing a silicon carbide wafer, a heater is arranged at the bottom of the etching cylinder, and a heat preservation shell is arranged on the outer surface of the heater, a heating cavity inside the heater is communicated with the etching cylinder cavity through a ventilation opening arranged at the bottom of the etching cylinder cavity, and characterized in that: a sealing drive unit and an automatic liquid adding unit are further included.

[0008] The sealing drive unit is used for sealing the feed opening after the bearing frame is pushed into the etching cylinder cavity.

[0009] The automatic liquid adding unit is used for automatically adding an appropriate amount of alkaline solution into the heating cavity according to the amount of the silicon carbide wafer placed on the bearing frame.

[0010] The bearing frame is mounted on the sealing drive unit, and the sealing drive unit, the heater and the automatic liquid adding unit are all mounted on a support frame.

[0011] As a preferred embodiment in the embodiment, the sealing drive unit comprises an L-shaped mounting frame mounted on the support frame, a sliding rail mounted at the top of the etching cylinder cavity, an electric track mounted on the L-shaped mounting frame, a moving slider mounted on the electric track, a rotating shaft rotatably arranged at the lower end of the moving slider, a sealing plate fixedly arranged on the rotating shaft and matched with the feed opening, a connecting sliding rod rotatably connected between the left end of the rotating shaft and the right end of the connecting sliding rod, the left end of the connecting sliding rod being slidingly arranged on the sliding rail, a first umbrella-shaped gear mounted on the right end of the rotating shaft, and a drive motor fixedly arranged at the lower end of the moving slider and having a second umbrella-shaped gear meshingly connected with the first umbrella-shaped gear.

[0012] The automatic liquid adding unit comprises a mounting groove mounted on the lower end of the connecting sliding rod, a movable stand rod slidingly penetrating through the support frame and arranged below the bearing frame, a T-shaped block movably arranged in the mounting groove, and a plurality of linear springs arranged at equal intervals and connecting the T-shaped block with the mounting groove, and an opening arranged at the bottom of the mounting groove and penetrating through the lower end of the T-shaped block and fixedly connected with the upper end of the bearing frame.

[0013] The upper end of the movable vertical rod is fixed with a contact plate in contact with the bottom of the bearing frame, and the two sides of the movable vertical rod are equally spaced with first guide wheels, and counterweight ropes are assembled and connected on the two first guide wheels, the end of the counterweight rope passes through the through hole provided on the movable vertical rod, the middle of the rope body of the counterweight rope is fixed in the through hole, the two ends of the counterweight rope are fixed with counterweight blocks of the same size, the two counterweight blocks always keep the same height, a plurality of drive teeth are arranged on the front end of the movable vertical rod at equal intervals from top to bottom, the drive teeth are in tooth connection with the one-way gear, the one-way gear is fixedly sleeved on the crankshaft, the crankshaft is rotatably arranged on the U-shaped frame arranged on the bottom of the support frame, two movable rods are movably arranged on the crankshaft, and the lower ends of the two movable rods are movably connected with the corresponding piston heads, the two piston heads are respectively sealingly and slidingly arranged in the corresponding piston cylinders, the two piston cylinders are communicated with the liquid storage cavity of the liquid storage barrel through the inlet pipes arranged at the lower ends, and the two piston cylinders are communicated with the heating cavity of the heater through the outlet pipes arranged at the side ends, the inlet pipes and the outlet pipes are respectively provided with inlet one-way valves and outlet one-way valves.

[0014] The weight of the two counterweight blocks is greater than the overall weight of the movable vertical rod.

[0015] The heater, the drive motor and the electric track are electrically connected with the PLC controller on the support frame.

[0016] As a preferred embodiment in the present embodiment, a self-locking unit is further included, which can lock the movable vertical rod when the movable vertical rod cannot continue to move downward, and can automatically release the locking of the movable vertical rod when the bearing frame enters the corrosion cylinder, is processed, is moved out and returns to the initial state.

[0017] As a preferred embodiment in the present embodiment, the self-locking unit includes a plurality of ratchets arranged in a straight line from top to bottom at the rear end of the movable vertical rod, a mounting stand fixed on the support frame and an L-shaped unlocking rod fixedly installed at the lower end of the bearing frame, the front end of the mounting stand is rotatably provided with a pawl matched with the ratchets, the movable end of the pawl is connected with the mounting stand through a self-locking spring, the rear end of the mounting stand is installed with a second guide wheel, the movable end of the pawl is fixed with a pull rope, one end of the pull rope passes through the axis of the self-locking spring and is assembled with the second guide wheel, and finally is fixedly connected with the lower end of the L-shaped self-locking rod, the lower end of the L-shaped self-locking rod slidingly penetrates the horizontal plate on the mounting stand, and the L-shaped self-locking rod is provided with a blocking block larger than the through hole on the horizontal plate.

[0018] As a preferred embodiment in the embodiment, an auxiliary unit is further included for assisting the movable vertical rod to overcome the resistance when driving the crankshaft to rotate.

[0019] As a preferred embodiment in the embodiment, the auxiliary unit includes a plurality of iron blocks mounted on the upper end of the T-shaped block and arranged at equal intervals, the lower end of each of the plurality of iron blocks is slidingly arranged in the inner cavity of the T-shaped block, a permanent magnet is fixed on the inner cavity portion of the mounting groove corresponding to each of the plurality of iron blocks, in the initial state, i.e., when the silicon carbide wafer is not placed on the carrier, the plurality of permanent magnets are adsorbed and fixed with the corresponding iron blocks, the linear spring is in a compressed state, the sum of the magnetic forces generated by the plurality of permanent magnets and the plurality of iron blocks is less than the gravity of a single silicon carbide wafer, and the sum of the magnetic forces is greater than the sum of the gravity of the plurality of iron blocks.

[0020] In summary, the technical effects and advantages of the present application are:

[0021] The automatic liquid adding unit of the device can automatically add an appropriate amount of alkaline solution according to the number of silicon carbide wafers, without manual addition operation, and without the need to remember the number of placed silicon carbide wafers.

[0022] In the present application, a self-locking unit is provided, which can allow the height of the movable vertical rod to be kept unchanged without the need for manual operation during the entire corrosion process, thereby reducing the labor intensity of the operator.

[0023] In the present application, an auxiliary unit is provided for assisting the movable vertical rod to overcome the resistance when driving the crankshaft to rotate, which can further improve the addition precision of the alkaline solution. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiment or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0025] Figure 1 is a front view of the structure of the present application;

[0026] Figure 2 is Figure 1 is a rear view of the structure of the present application;

[0027] Figure 3 is Figure 2 is a partial structure schematic view of the automatic liquid adding unit in the present application;

[0028] Figure 4 is Figure 3 is a partial front view and enlarged structure schematic view in the present application;

[0029] Figure 5 for Figure 4 schematic diagram of the counterweight structure in the middle;

[0030] Figure 6 for Figure 3 schematic diagram of the self-locking unit structure in the middle;

[0031] Figure 7 for Figure 6 schematic diagram of the enlarged structure at A in the middle;

[0032] Figure 8 for Figure 2 schematic diagram of the cross-sectional structure of the mounting groove in the middle;

[0033] Figure 9 for Figure 8 schematic diagram of the cross-sectional structure of the T-shaped block in the middle;

[0034] Figure 10 for Figure 1 schematic diagram of the bearing frame structure in the middle.

[0035] In the figure: 1, support frame; 2, heater; 3, corrosion cylinder; 4, sealing drive unit; 41, sealing plate; 42, connecting slide rod; 43, L-shaped mounting frame; 44, electric track; 45, moving slide block; 46, drive motor; 47, rotating shaft; 5, automatic liquid adding unit; 51, mounting groove; 52, T-shaped block; 53, through port; 54, movable vertical rod; 55, contact plate; 56, drive tooth; 57, first guide wheel; 58, counterweight block; 59, counterweight rope; 510, crankshaft; 511, one-way gear; 512, movable rod; 513, piston head; 514, piston cylinder; 515, U-shaped frame; 516, liquid inlet pipe; 517, liquid outlet pipe; 518, liquid storage barrel; 519, linear spring; 6, bearing frame; 7, self-locking unit; 71, mounting vertical frame; 72, pawl; 73, self-locking spring; 74, pull rope; 75, second guide wheel; 76, blocking block; 77, L-shaped self-locking rod; 78, L-shaped unlocking rod; 79, ratchet; 8, iron block; 9, permanent magnet; 10, air vent opening; 11, arc-shaped limiting rod; 12, buffer spring. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0037] Embodiment: refer to Figures 1-5The shown automatic liquid adding type silicon carbide etching equipment includes an etching cylinder 3 with a feed opening at the right end and a cylindrical structure, and a bearing frame 6 for bearing a silicon carbide wafer, the bottom of the etching cylinder 3 is provided with a heater 2, and the outer surface of the heater 2 is provided with a heat preservation shell, the heating cavity inside the heater 2 is communicated with the inner cavity of the etching cylinder 3 through the air opening 10 arranged at the bottom of the inner cavity of the etching cylinder 3, and the automatic liquid adding unit 5 is further included;

[0038] The sealing drive unit 4 is used to push the bearing frame 6 into the inner cavity of the etching cylinder 3 and seal the feed opening;

[0039] The automatic liquid adding unit 5 automatically adds an appropriate amount of alkaline solution into the heating cavity according to the amount of the silicon carbide wafer placed on the bearing frame 6;

[0040] The bearing frame 6 is installed on the sealing drive unit 4, and the sealing drive unit 4, the heater 2 and the automatic liquid adding unit 5 are all installed on the support frame 1.

[0041] As a preferred embodiment in the embodiment, the sealing drive unit 4 includes an L-shaped mounting frame 43 installed on the support frame 1 and a sliding rail installed at the top of the inner cavity of the etching cylinder 3, an electric track 44 is installed on the L-shaped mounting frame 43, a moving block 45 is installed on the electric track 44, a rotating shaft 47 is rotationally arranged at the lower end of the moving block 45, a sealing plate 41 adapted to the feed opening is fixed on the rotating shaft 47, the left end of the rotating shaft 47 is rotationally connected with the right end of a connecting slide rod 42, the left end of the connecting slide rod 42 is slidingly arranged on the sliding rail, a first umbrella-shaped gear is installed on the right end of the rotating shaft 47, a drive motor 46 is fixed at the lower end of the moving block 45, and a second umbrella-shaped gear meshingly connected with the first umbrella-shaped gear is installed at the lower end of the drive motor 46;

[0042] The automatic liquid adding unit 5 includes an installation groove 51 installed at the lower end of the connecting slide rod 42 and an active vertical rod 54 slidingly penetrating the support frame 1 below the bearing frame 6, a T-shaped block 52 is movably arranged in the installation groove 51, and the T-shaped block 52 is connected with the installation groove 51 through a plurality of linear springs 519 arranged at equal intervals, an opening is arranged at the lower end of the T-shaped block 52 to fixedly connect with the upper end of the bearing frame 6 through the bottom of the installation groove 51;

[0043] The upper end of the movable vertical rod 54 is fixed with a contact plate 55 in contact with the bottom of the bearing frame 6, and the two sides of the movable vertical rod 54 are equally spaced with first guide wheels 57, and the two first guide wheels 57 are fitted and connected with counterweight ropes 59, the ends of the counterweight ropes 59 pass through the through hole 53 provided on the movable vertical rod 54, the middle of the rope body of the counterweight rope 59 is fixed in the through hole 53, and the two ends of the counterweight rope 59 are fixed with counterweight blocks 58 of the same size, the two counterweight blocks 58 always keep the same height, and the front end of the movable vertical rod 54 is provided with a plurality of drive teeth 56 at equal intervals from top to bottom, the drive teeth 56 are in tooth connection with the one-way gear 511, the one-way gear 511 is fixedly sleeved on the crankshaft 510, the crankshaft 510 is rotatably arranged on the U-shaped frame 515 arranged on the bottom of the support frame 1, two movable rods 512 are movably arranged on the crankshaft 510, and the lower ends of the two movable rods 512 are movably connected with the corresponding piston heads 513, the two piston heads 513 are sealingly and slidably arranged in the corresponding piston cylinders 514, the two piston cylinders 514 are communicated with the liquid storage cavity of the liquid storage barrel 518 through the liquid inlet pipe 516 arranged at the lower end, and the two piston cylinders 514 are communicated with the heating cavity of the heater 2 through the liquid outlet pipe 517 arranged at the side end, and the liquid inlet pipe 516 and the liquid outlet pipe 517 are respectively provided with liquid inlet one-way valves and liquid outlet one-way valves;

[0044] The weight of the two counterweight blocks 58 is greater than the overall weight of the movable vertical rod 54;

[0045] The heater 2, the drive motor 46 and the electric track 44 are electrically connected with the PLC controller on the support frame 1.

[0046] When the initial state, the lower end of the carrier 6 is just in contact with the contact plate 55, a certain number of silicon carbide wafers are placed on the carrier 6, within the elastic range of the linear spring 519, for each silicon carbide wafer placed on the carrier 6, it will be equidistantly lowered by a distance, while the carrier 6 is lowered, part of its weight acts on the contact plate 55, so that the movable vertical rod 54 overcomes the total weight of the two counterweights 58 and the resistance to rotate the crankshaft 510 to move downward, with the downward movement of the movable vertical rod 54, the engagement connection of the driving teeth 56 and the one-way gear 511, so that the crankshaft 510 rotates, the crankshaft 510 drives the two movable rods 512 to move up and down, thereby driving the two piston heads 513 to move up and down in the corresponding piston cylinder 514, finally the alkaline solution in the storage barrel 518 is continuously pumped into the heating cavity, for each distance that the carrier 6 drives the movable vertical rod 54 to lower, a certain amount of alkaline solution will be pumped into the heating cavity, even if the movable vertical rod 54 has a small distance of descent, a corresponding amount of alkaline solution will be pumped into the heating cavity, which is beneficial to the precise control of the amount of alkaline solution, when the silicon carbide wafers are placed (at this time, the height of the movable vertical rod 54 can be kept unchanged by hand until the carrier 6 is corroded and then restored to its original position), control the motor to work, drive the motor 46 to rotate the shaft 47, and finally make the sealing plate 41 rotate outward by a certain angle, at this angle, when the sealing plate 41 moves horizontally, it will not come into contact with the contact plate 55, after the angle adjustment of the sealing plate 41 is completed, the electric track 44 drives the sealing plate 41 and the carrier 6 to move horizontally, that is, to move towards the inner cavity of the corrosion cylinder 3, and when the carrier 6 moves completely into the corrosion cylinder 3 and the sealing plate 41 passes over the contact plate 55, control the drive motor 46 to move in the opposite direction and restore the original angle, and then under the drive of the electric slide rail 44, the sealing plate 41 will form a seal with the inlet opening end of the corrosion cylinder 3, at this time, control the heater 2 to control, the heater 2 heats the alkaline solution in the heating cavity to form alkaline steam to corrode the silicon carbide wafers, after the corrosion is completed (at this time, the heater 2 stops heating), through the cooperation of the electric track 44 and the drive motor 46, the carrier 6 and the sealing plate 41 (which will pass over the contact plate 55 again) are restored to their original positions (after restoration, the hand holding the height of the movable vertical rod 54 can be released, under the action of the gravity of the two counterweights 58, the movable vertical rod 54 will move upward and restore to its original position, and in this process, the crankshaft 510 will not rotate, at this time, the lower end of the counterweight 58 will be in contact with the support block on the U-shaped frame 515), the automatic liquid adding unit 5 can automatically add an appropriate amount of alkaline solution according to the number of silicon carbide wafers, without manual addition operation, and without the need to remember the number of silicon carbide wafers placed.

[0047] It should be noted that, as Figure 10As shown, the carrier frame 6 comprises a plurality of arc-shaped support rods 61 arranged at equal intervals, and the arc-shaped support rods are connected by a plurality of connecting rods 62. The silicon carbide wafer is placed in the clamping gap between two adjacent arc-shaped support rods 61, and the lower end of the silicon carbide wafer is supported by the connecting rod 62. Second, the device is suitable for automatic liquid adding operation of silicon carbide wafers of the same specification (so that the weight of each wafer is consistent), which can make the addition amount of alkaline solution more accurate. The device is also suitable for automatic liquid adding operation of silicon carbide wafers with the same thickness and different diameters. Third, by arranging the counterweight block, the resistance of the carrier frame 6 to downward movement can be kept constant. At the same time, the counterweight block 58 can offset the gravitational force of the movable vertical rod 54, so that the carrier frame 6 will be subjected to smaller resistance when moving downward, which is beneficial to the accurate addition of alkaline solution. Fourth, the device can automatically and quantitatively heat the silicon carbide wafer while placing it, which can improve work efficiency.

[0048] As a preferred embodiment in this embodiment, as shown in Figure 3 It also includes a self-locking unit 7, which can lock the movable vertical rod 54 when it cannot continue to move downward. When the carrier frame 6 enters the etching cylinder 3 and is processed, and then moves out and returns to the initial state, the locking of the movable vertical rod 54 can be automatically released.

[0049] The self-locking unit 7 can make the height of the movable vertical rod 54 remain unchanged without the need for manual operation during the entire etching process, thereby reducing the labor intensity of the operator.

[0050] As a preferred embodiment in this embodiment, as shown in Figure 3 And Figure 7 As shown, the self-locking unit 7 comprises a plurality of ratchet teeth 79 arranged in a straight line from the rear end of the movable vertical rod 54 and downward, a mounting stand 71 fixed on the support frame 1, and an L-shaped unlocking rod 78 fixedly installed at the lower end of the carrier frame 6. The front end of the mounting stand 71 is rotationally provided with a pawl 72 adapted to the ratchet teeth 79. The movable end of the pawl 72 is connected to the mounting stand 71 through a self-locking spring 73. A second guide wheel 75 is installed on the rear end of the mounting stand 71. A pull rope 74 is fixed to the movable end of the pawl 72. One end of the pull rope 74 passes through the axis of the self-locking spring 73 and is assembled with the second guide wheel 75, and finally fixedly connected with the lower end of the L-shaped self-locking rod 77. The lower end of the L-shaped self-locking rod 77 slides through the horizontal plate on the mounting stand 71. The L-shaped self-locking rod 77 is provided with a blocking block 76 larger than the through hole on the horizontal plate.

[0051] When the movable upright 54 can no longer move downwards, the pawl 72 and ratchet 79 prevent the movable upright 54 from moving upwards under the weight of the counterweight 58, thus locking the movable upright 54. When the silicon carbide wafers on the support frame 6 have been etched and returned to their original positions, the silicon carbide wafers on the support frame 6 can be removed. As the silicon carbide wafers are removed one by one, the support frame 6 gradually raises the height of the L-shaped unlocking rod 78 under the action of the linear spring 519. When all the silicon carbide wafers on the support frame 6 have been removed, the L-shaped unlocking rod 78 will contact the L-shaped self-locking rod 77 and move it upwards a certain distance. As the L-shaped self-locking rod 77 moves upwards a certain distance, the pull rope 74 will cause the pawl 72 to compress the self-locking spring 73, releasing the self-locking state of the pawl 72 and ratchet 79. Under the weight of the counterweight 58, the movable upright 54 returns to its original position. The self-locking unit 7 eliminates the need to manually maintain the height of the movable pole 54 throughout the corrosion process, reducing the workload of operators.

[0052] It should be noted that: First, the weight of the etched silicon carbide wafer is lower than that of the untreated silicon carbide wafer; therefore, the lower end of the support frame 6 holding the etched wafer is located above the lower end of the support frame 6 when the wafer is untreated; Second, if... Figure 7 As shown, the pawl 72 includes a first part and a second part, which are connected by a buffer spring 12. An arc-shaped limiting rod 11, consistent with the movement path of the first part, is fixedly mounted on the first part. The end of the arc-shaped limiting rod 11 away from the first part is slidably disposed within the cavity of the second part. The pawl 72 is thus configured as two parts connected by the buffer spring 12. When the pawl 72 rotates around the rotation axis under the tension of the pull rope 74, it exerts a downward force on the ratchet 79. At this time, the ratchet 72 can pass through the arc-shaped limiting rod 11 on the first part. The lever 13 moves toward the inner cavity of the second part (while also compressing the buffer spring 12), thereby buffering the force on the ratchet 79. This prevents the movable upright 54 from moving downwards when the pawl 72 and ratchet 79 are released from self-locking (when the movable upright 54 moves downwards, it will cause the alkaline solution in the storage tank 518 to be pumped into the heating chamber, resulting in unnecessary waste of alkaline solution). It also avoids the situation where the L-shaped unlocking lever 78 needs to apply a large upward force to the L-shaped self-locking lever 77 to release the self-locking state.

[0053] As a preferred embodiment of this invention, an auxiliary unit is also included to assist the movable upright 54 in overcoming the resistance encountered when driving the crankshaft 510 to rotate.

[0054] Due to the existence of resistance, when a small number of wafers are placed on the carrier 6, such as one wafer, the moving vertical rod 54 is easily lowered by a small distance, resulting in too little alkaline solution being added to the heating cavity, which cannot cause good corrosion treatment of the wafer. Therefore, the auxiliary unit is arranged to overcome the resistance when the driving crankshaft 510 rotates, so that an appropriate amount of alkaline solution can be added to the heating cavity.

[0055] As a preferred embodiment in the present embodiment, as shown in Figure 8 and Figure 9 The auxiliary unit includes a plurality of iron blocks 8 mounted on the upper end of the T-shaped block 52 at equal intervals, the lower end of each of the plurality of iron blocks 8 is slidingly arranged in the inner cavity of the T-shaped block 52, and a permanent magnet 9 is fixed on the inner cavity portion of the slot 51 corresponding to the plurality of iron blocks 8. In the initial state, that is, when the carrier 6 does not place a silicon carbide wafer, the plurality of permanent magnets 9 are adsorbed and fixed with the corresponding iron blocks 8, the linear spring 519 is in a compressed state, the sum of the magnetic force generated by the plurality of permanent magnets 9 and the plurality of iron blocks 8 is less than the gravity of a single silicon carbide wafer, and the sum of the magnetic force is greater than the sum of the gravity of the plurality of iron blocks 8.

[0056] At the beginning, through the magnetic attraction of the permanent magnet 9 and the iron block 8, only part of the weight of the carrier 6 acts on the linear spring 519, and the weight of the plurality of iron blocks 8 does not act on the linear spring 519 (the sum of the weight of the plurality of iron blocks 8 is equal to the resistance when the driving crankshaft 510 rotates, which further improves the accuracy of the automatic addition of alkaline solution in this state), when a wafer is placed on the carrier 6, under the action of its gravity, the permanent magnet 9 and the iron block 8 are separated to generate a gap (the magnetic force between the permanent magnet 9 and the iron block 8 is related to the interval, when the interval between the two is larger, the magnetic force will quickly become smaller), the magnetic force is weakened, and finally the weight of the carrier 6, the single wafer and the plurality of iron blocks all act on the linear spring 519 (at this time, the iron block 8 is not affected by the magnetic force), thereby making the moving vertical rod 54 move downward by a larger distance under the action of the carrier 6 (this distance is compared with the state without the permanent magnet 9 and the iron block 8), that is, even for a single wafer corrosion, an appropriate amount of alkaline solution can be added to the heating cavity, and the wafer can continue to be added to the carrier 6. Within the elastic range of the linear spring 519, with each additional wafer, the carrier 6 drives the moving vertical rod 54 to move downward at equal intervals by a certain distance, thereby adding an equal amount of alkaline solution to the heating cavity. A plurality of wafers can be placed on the carrier 6, and the permanent magnet 9 and the iron block 8 can further improve the accuracy of the amount of alkaline solution added compared to the state without the permanent magnet 9 and the iron block 8. After the corrosion is completed, after all the silicon carbide wafers on the carrier 6 are removed, when the carrier 6 rises to a certain height and cannot continue to rise, the iron block 8 moves upward relative to the carrier 6 and contacts and adsorbs the permanent magnet 9 through the magnetic force.

[0057] It should be noted that, first, the outer surface of the iron block 8 is provided with a corrosion-resistant coating; second, a plurality of downwardly inclined flow guide holes are arranged at the side end of the T-shaped block 52, and the plurality of flow guide holes are respectively communicated with the corresponding sliding groove inner cavities accommodating the iron block 8, so that the liquid in the sliding groove can be guided out through the flow guide holes, thereby avoiding increasing the overall weight of the bearing frame 6 and avoiding affecting the subsequent alkali solution adding precision; third, the permanent magnet is made of high-temperature resistant material.

[0058] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for limiting the present application, although the foregoing embodiments of the present application are described in detail, for those skilled in the art, it still can be modified, or part of the technical features of the equivalent replacement, within the spirit and principles of the present application, any modification, equivalent replacement, improvement, etc., should be included within the scope of the present application.

Claims

1. An automatic liquid feeding type silicon carbide etching device, comprising an etching cylinder (3) with a feed opening at the right end and a cylindrical structure, and a carrier frame (6) for carrying a silicon carbide wafer, the bottom of the etching cylinder (3) is provided with a heater (2), and the outer surface of the heater (2) is provided with a heat preservation shell, the heating cavity inside the heater (2) is communicated with the inner cavity of the etching cylinder (3) through the ventilation opening (10) provided at the bottom of the inner cavity of the etching cylinder (3), characterized in that it further comprises a sealing drive unit (4) and an automatic liquid feeding unit (5); The sealing drive unit (4) is used to seal the feed opening after the carrier frame (6) is pushed into the inner cavity of the etching cylinder (3); The automatic liquid feeding unit (5) automatically adds an appropriate amount of alkaline solution into the heating cavity according to the amount of the silicon carbide wafer placed on the carrier frame (6); The carrier frame (6) is installed on the sealing drive unit (4), and the sealing drive unit (4), the heater (2) and the automatic liquid feeding unit (5) are all installed on the support frame (1); The sealing drive unit (4) comprises an L-shaped mounting bracket (43) installed on the support frame (1) and a sliding rail installed at the top of the inner cavity of the etching cylinder (3), an electric track (44) is installed on the L-shaped mounting bracket (43), a moving slider (45) is installed on the electric track (44), a rotating shaft (47) is rotationally arranged at the lower end of the moving slider (45), a sealing plate (41) matched with the feed opening is fixed on the rotating shaft (47), the left end of the rotating shaft (47) is rotationally connected with the right end of a connecting slide rod (42), the left end of the connecting slide rod (42) is slidingly arranged on the sliding rail, a first umbrella gear is installed on the right end of the rotating shaft (47), a drive motor (46) is fixed at the lower end of the moving slider (45), and a second umbrella gear meshingly connected with the first umbrella gear is installed at the lower end of the drive motor (46); The automatic liquid feeding unit (5) comprises a mounting groove (51) installed at the lower end of the connecting slide rod (42) and an active vertical rod (54) slidingly penetrating through the support frame (1) below the carrier frame (6), a T-shaped block (52) is movably arranged in the mounting groove (51), the T-shaped block (52) is connected with the mounting groove (51) through a plurality of linear springs (519) arranged at equal intervals, and the lower end of the T-shaped block (52) is fixedly connected with the upper end of the carrier frame (6) through an opening provided at the bottom of the mounting groove (51). The upper end of the movable vertical rod (54) is fixed with a contact plate (55) in contact with the bottom of the bearing frame (6), and the two sides of the movable vertical rod (54) are equidistantly provided with first guide wheels (57), and the two first guide wheels (57) are assembled and connected with counterweight ropes (59), the ends of the counterweight ropes (59) pass through the through holes (53) provided on the movable vertical rod (54), the middle of the rope body of the counterweight rope (59) is fixed in the through hole (53), and the two ends of the counterweight rope (59) are fixed with counterweight blocks (58) of the same specification, the two counterweight blocks (58) always keep the same height, a plurality of drive teeth (56) are equidistantly arranged on the front end of the movable vertical rod (54) from top to bottom, the drive teeth (56) are in tooth connection with one-way gears (511), the one-way gears (511) are fixedly sleeved on a crankshaft (510), the crankshaft (510) is rotatably arranged on the U-shaped frame (515) arranged at the bottom of the support frame (1), two movable rods (512) are movably arranged on the crankshaft (510) one above the other, and the lower ends of the two movable rods (512) are movably connected with corresponding piston heads (513), the two piston heads (513) are respectively sealingly and slidingly arranged in corresponding piston cylinders (514), the two piston cylinders (514) are communicated with the liquid storage cavity of the liquid storage barrel (518) through the liquid inlet pipe (516) arranged at the lower end, and the two piston cylinders (514) are communicated with the heating cavity of the heater (2) through the liquid outlet pipe (517) arranged at the side end, the liquid inlet pipe (516) and the liquid outlet pipe (517) are respectively provided with liquid inlet one-way valves and liquid outlet one-way valves; The weights of the two counterweight blocks (58) are greater than the overall weight of the movable vertical rod (54); The heater (2), the drive motor (46) and the electric track (44) are electrically connected with the PLC controller on the support frame (1).

2. The automatic liquid-adding type silicon carbide etching apparatus according to claim 1, characterized by: Further comprising a self-locking unit (7), which can lock the movable vertical rod (54) when the movable vertical rod (54) cannot continue to move downward, and can automatically release the locking of the movable vertical rod (54) when the bearing frame (6) enters the corrosion cylinder (3) and is processed, removed and restored to the initial state.

3. The automatic liquid-adding type silicon carbide etching apparatus according to claim 2, characterized by: The self-locking unit (7) comprises a plurality of ratchets (79) arranged in a straight line from the rear end of the movable vertical rod (54) and below, a mounting stand (71) fixed on the support frame (1), and an L-shaped unlocking rod (78) fixedly installed at the lower end of the bearing frame (6). The front end of the mounting stand (71) is rotatably provided with a pawl (72) matched with the ratchet (79). The movable end of the pawl (72) is connected with the mounting stand (71) through a self-locking spring (73). A second guide wheel (75) is installed on the rear end of the mounting stand (71). A pull rope (74) is fixed on the movable end of the pawl (72), one end of the pull rope (74) penetrates the axis of the self-locking spring (73) and is assembled with the second guide wheel (75), and finally fixedly connected with the lower end of the L-shaped self-locking rod (77). The lower end of the L-shaped self-locking rod (77) slides through the horizontal plate on the mounting stand (71). The L-shaped self-locking rod (77) is provided with a blocking block (76) larger than the through hole on the horizontal plate.

4. The automatic liquid-adding type silicon carbide etching apparatus according to claim 1, characterized by: It also includes an auxiliary unit for assisting the movable vertical rod (54) to overcome the resistance when driving the rotation of the crankshaft (510).

5. The automatic liquid-adding type silicon carbide etching apparatus according to claim 4, characterized by: The auxiliary unit comprises a plurality of iron blocks (8) installed on the upper end of the T-shaped block (52) and arranged at equal intervals. The lower end of each of the plurality of iron blocks (8) is slidably arranged in the inner cavity of the T-shaped block (52). A permanent magnet (9) is fixed on the inner cavity portion of the mounting groove (51) corresponding to each of the plurality of iron blocks (8). In the initial state, i.e. when the bearing frame (6) does not place the silicon carbide wafer, the plurality of permanent magnets (9) are adsorbed and fixed with the corresponding iron blocks (8). The linear spring (519) is in a compressed state. The sum of the magnetic forces generated by the plurality of permanent magnets (9) and the plurality of iron blocks (8) is less than the gravity of a single silicon carbide wafer, and the sum of the magnetic forces is greater than the sum of the gravities of the plurality of iron blocks (8).

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