Alkaline vapor etching silicon carbide wafer equipment

Abstract

The present invention discloses an alkaline steam etching silicon carbide wafer device and an operation method, comprising an etching cylinder with a feeding opening at the right end and a cylindrical structure and a support frame for carrying silicon carbide wafers, a heater is provided at the bottom of the etching cylinder, and a heat-insulating shell is provided on the outer surface of the heater, and a heating chamber inside the heater is communicated with the inner cavity of the etching cylinder through a ventilation opening provided at the bottom of the inner cavity of the etching cylinder, and is characterized in that it also includes a sealing drive unit, an automatic liquid adding unit and an atomization cleaning and cooling unit. 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 adding operation, and without remembering the number of placed silicon carbide wafers.

Description

Technical Field

[0001] The invention relates to the technical field of silicon carbide wafers, and in particular to an alkaline steam etching silicon carbide wafer device. Background Art

[0002] Silicon carbide is one of the most widely studied third-generation semiconductor materials and is widely used in photovoltaics, new energy vehicles, smart

[0003] It has good application prospects in areas such as power grids, and related research and products are continuously launched, with good economic benefits and high application value.

[0004] Currently, an important issue restricting the application of silicon carbide devices is wafer defects. After continuous efforts by scientific research and industry, defects such as inclusions, voids, and polymorphism in high-quality silicon carbide wafers have been completely eliminated, and defects such as micropipes and dislocations have become the focus of current attention. Micropipes can cause direct failure of devices, and dislocations such as edge dislocations, screw dislocations, and basal plane dislocations can reduce carrier lifetimes and affect device performance. Therefore, locating and analyzing such defects has become a major issue in material preparation and device manufacturing.

[0005] Important needs of work.

[0006] Corrosion is the main method for characterizing silicon carbide defects. By controlling the corrosion process, one or several defects can be quickly distinguished. High-temperature alkaline vapor has a good distinguishing effect on silicon carbide corrosion defects.

[0007] After searching, a Chinese patent document with the authorization announcement number CN113550012B and the name "A device for alkaline vapor corrosion of silicon carbide wafers" was obtained. According to the contents in its specification, before the device corrodes the silicon carbide wafers, the operator needs to add a certain amount of alkaline solution into the corrosion-resistant boat according to the number of silicon carbide wafers placed. Manual addition is troublesome, and each time adding, it is necessary to clearly understand the number of specific silicon carbide wafers placed to avoid excessive addition of alkaline solution (generally, the number of silicon carbide wafers needs to be confirmed before adding the alkaline solution). Therefore, the present application provides an alkaline vapor corrosion silicon carbide wafer equipment to meet the needs. Summary of the invention

[0008] The purpose of the present application is to provide an alkaline vapor etching silicon carbide wafer device to solve the technical problem in the prior art that an appropriate amount of alkaline solution needs to be manually added according to the number of placed silicon carbide wafers.

[0009] To achieve the above-mentioned purpose, the present application provides the following technical solutions: an alkaline vapor etching silicon carbide wafer device, comprising an etching cylinder with a cylindrical structure and a feeding opening at the right end, and a carrier for carrying silicon carbide wafers, a heater is arranged at the bottom of the etching cylinder, and a heat-insulating shell is arranged on the outer surface of the heater, and a heating chamber inside the heater communicates with the inner cavity of the etching cylinder through a ventilation opening arranged at the bottom of the inner cavity of the etching cylinder, characterized in that: it also includes a sealing drive unit, an automatic liquid adding unit and an atomizing cleaning and cooling unit;

[0010] Sealing drive unit: used to push the carrier into the inner cavity of the corrosion cylinder and then seal the feed opening;

[0011] Automatic liquid adding unit: automatically and quantitatively adding an appropriate amount of alkaline solution into the heating chamber according to the amount of silicon carbide wafers placed on the carrier;

[0012] The carrier is mounted on the sealing drive unit, and the sealing drive unit, the heater and the automatic liquid adding unit are all mounted on the supporting frame;

[0013] Atomization cleaning and cooling unit: used for cleaning and cooling the corroded silicon carbide wafers, and also for cooling and liquefying the excess alkaline vapor in the etching cylinder.

[0014] As a preferred implementation manner in this embodiment, the sealing drive unit includes an L-shaped mounting frame installed on the supporting frame and a slide rail installed on the top of the inner cavity of the corrosion cylinder, the L-shaped mounting frame is installed with an electric track, a moving slider is installed on the electric track, a rotating shaft is rotatably provided at the lower end of the moving slider, a sealing plate adapted to the feed opening is fixed on the rotating shaft, the left end of the rotating shaft is rotatably connected to the right end of the connecting slide rod, the left end of the connecting slide rod is slidably provided on the slide rail, a first bevel gear is installed on the right end of the rotating shaft, a driving motor is fixed to the lower end of the moving slider, and a second bevel gear meshingly connected to the first bevel gear is installed at the lower end of the driving motor;

[0015] The automatic liquid adding unit comprises a mounting groove installed at the lower end of the connecting slide rod and a movable vertical rod located below the supporting frame and slidingly passing through the supporting frame, a T-shaped block is movably arranged in the mounting groove, and the T-shaped block is connected to the mounting groove through a plurality of linear springs arranged at equal intervals, and the lower end of the T-shaped block passes through an opening provided at the bottom of the mounting groove and is fixedly connected to the upper end of the supporting frame;

[0016] A contact plate in contact with the bottom of the carrier frame is fixed to the upper end of the movable upright pole, first guide wheels are evenly spaced on both sides of the movable upright pole, counterweight ropes are assembled and connected to the two first guide wheels, the ends of the counterweight ropes pass through the through-holes provided on the movable upright pole, the middle part of the rope body of the counterweight rope is fixed in the through-holes, counterweight blocks of the same specifications are fixed at both ends of the counterweight rope, and the two counterweight blocks always keep the same height, a plurality of driving teeth are evenly spaced from top to bottom on the front end of the movable upright pole, the driving teeth are toothed with the one-way gear, and the one-way gear is connected to the one-way gear. The gear is fixedly sleeved on the crankshaft, and the crankshaft is rotatably arranged on a U-shaped frame arranged at the bottom of the support frame. Two movable rods are movably installed on the crankshaft, one up and one down, and the lower ends of the two movable rods are movably connected with the corresponding piston heads. The two piston heads are respectively sealed and slidably arranged in the corresponding piston cylinders. The two piston cylinders are communicated with the liquid storage chamber of the liquid storage barrel through the liquid inlet pipes arranged at the lower ends, and the two piston cylinders are communicated with the heating chamber of the heater through the liquid outlet pipes arranged at the side ends. The liquid inlet one-way valve and the liquid outlet one-way valve are respectively arranged on the liquid inlet pipe and the liquid outlet pipe;

[0017] The weight of the two counterweight blocks is greater than the overall weight of the movable upright pole;

[0018] The atomizing cleaning and cooling unit includes a spray pipe with a valve on the liquid inlet end and a discharge pipe connected to the inner cavity of the heating chamber and with a valve. A plurality of atomizing spray heads are arranged at equal intervals on the spray pipe, and the plurality of atomizing spray heads are all located in the inner cavity of the corrosion cylinder. The discharge pipe is located at the bottom of the heater.

[0019] The heater, the drive motor and the electric track are all electrically connected to the PLC controller on the support frame.

[0020] As a preferred implementation manner in this embodiment, it also includes a self-locking unit, which can lock the movable vertical rod when the movable vertical rod cannot continue to move downward. After the support frame enters the corrosion cylinder for processing and moves out and returns to the initial state, the movable vertical rod can be automatically unlocked.

[0021] As a preferred implementation scheme in this embodiment, the self-locking unit includes a plurality of ratchets arranged at the rear end of the movable upright and arranged in a straight line from top to bottom, a mounting stand fixed on the support frame, and an L-shaped unlocking rod whose upper end is fixedly mounted on the lower end of the carrier frame, the front end of the mounting stand is rotatably provided with a pawl adapted to the ratchets, the movable end of the pawl is connected to the mounting stand through a self-locking spring, a second guide wheel is installed on the rear end of the mounting stand, a pull rope is fixed on the movable end of the pawl, and one end of the pull rope passes through the axis of the self-locking spring and is assembled with the second guide wheel and is finally fixedly connected to the lower end of the L-shaped self-locking rod, the lower end of the L-shaped self-locking rod slides through the horizontal plate on the mounting stand, and the L-shaped self-locking rod is provided with a blocking block larger than the passing opening on the horizontal plate.

[0022] As a preferred implementation scheme in this embodiment, the pawl includes a first part and a second part, the first part and the second part are connected by a buffer spring, an arc-shaped limit rod consistent with the movement path of the first part is fixedly provided on the first part, and the arc-shaped limit rod is slidably set in the inner cavity of the second part away from the end of the first part.

[0023] As a preferred implementation manner in this embodiment, it also includes an auxiliary unit for assisting the movable upright rod to overcome the resistance encountered when driving the crankshaft to rotate.

[0024] As a preferred implementation mode in this embodiment, the auxiliary unit includes a plurality of iron blocks installed on the upper end of the T-shaped block and arranged at equal intervals, the lower ends of the plurality of iron blocks are slidably arranged in the inner cavity of the T-shaped block, and permanent magnets are fixed on the inner cavity parts of the mounting grooves corresponding to the plurality of iron blocks. In the initial state, that is, when no silicon carbide wafer is placed on the carrier frame, the plurality of permanent magnets are adsorbed and fixed to 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 8.

[0025] The operating method of the alkaline vapor etching silicon carbide wafer equipment is characterized by comprising the following steps:

[0026] S1: Manual loading and quantitative automatic liquid addition, placing silicon carbide wafers one by one on the carrier, within the elastic range of the linear spring, each time a silicon carbide wafer is added, the carrier moves downward by a certain distance, as the silicon carbide wafers continue to increase, the carrier contacts the contact plate and drives the movable vertical rod to move downward, and the alkaline solution stored in the liquid storage barrel is continuously pumped into the heating chamber through the movement of the piston until the silicon carbide wafers are placed, and the liquid addition stops;

[0027] S2: feeding and sealing, controlling the driving motor and the electric track to work, the moving slider drives the carrier and the sealing plate to move toward the inner cavity of the etching cylinder, and at the same time, the driving motor drives the rotating shaft to rotate, and the sealing plate is driven by the rotating shaft to rotate a certain angle and then stops moving, and after the sealing plate passes over the contact plate, the driving motor rotates and returns to its original position, and the sealing plate continues to move close to the etching cylinder and finally completes the sealing of the etching cylinder, at this time, the carrier moves to the inner cavity of the etching cylinder, controls the heater to work, heats the alkaline solution in the heating chamber, and vaporizes it to form alkaline steam to process the silicon carbide wafer;

[0028] S3: cleaning and cooling. After the alkaline steam has completed the etching treatment of the silicon carbide wafer, deionized water at room temperature is injected into the spray pipe through the pump body to perform atomized spray cleaning on the silicon carbide wafer. At the same time, atomization can quickly cool down the excess alkaline steam and air in the etching cylinder, and finally liquefy the steam and gather it in the heating chamber. The cleaning liquid can be discharged through the drain pipe. After cleaning, the carrier is stationary in the etching cylinder for a period of time, and the droplets on the wafer fall into the heating chamber, and then the electric track and the drive motor are controlled to work, so that the carrier and the sealing plate return to their original positions.

[0029] In summary, the technical effects and advantages of the present invention are as follows:

[0030] The invention has a reasonable structure. 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, without manual adding operation, and without remembering the number of silicon carbide wafers placed. The atomization cleaning and cooling unit can clean and cool the corroded silicon carbide wafers, and also cool and liquefy the excess alkaline steam in the corrosion cylinder.

[0031] In the present invention, a self-locking unit is provided, so that the height of the movable upright pole can be kept unchanged without manual effort during the entire corrosion process, thereby reducing the labor intensity of the operator;

[0032] In the present invention, an auxiliary unit is provided to assist the movable upright rod to overcome the resistance encountered when the crankshaft is driven to rotate, thereby further improving the adding accuracy of the alkaline solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 It is a front view structural schematic diagram of the present invention;

[0035] Figure 2 for Figure 1 Middle and rear view structure diagram;

[0036] Figure 3 for Figure 2 Schematic diagram of the local structure of the automatic liquid adding unit;

[0037] Figure 4 for Figure 3 The middle part is viewed frontally and the enlarged structural diagram;

[0038] Figure 5 for Figure 4 Schematic diagram of the structure of the middle counterweight block;

[0039] Figure 6 for Figure 3 Schematic diagram of the self-locking unit structure;

[0040] Figure 7 for Figure 6 The enlarged structural diagram at A in the middle;

[0041] Figure 8 for Figure 2 Schematic diagram of the cross-section structure of the middle installation groove;

[0042] Fig. 9 for Figure 8 Schematic diagram of the cross-section structure of the middle T-shaped block;

[0043] Fig.10 for Figure 1 Schematic diagram of the middle load-bearing frame structure.

[0044] 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, driving motor; 47, rotating shaft; 5, automatic liquid adding unit; 51, mounting groove; 52, T-shaped block; 53, through-hole; 54, movable vertical rod; 55, contact plate; 56, driving gear; 57, first guide wheel; 58, counterweight block; 59, counterweight rope; 510, crankshaft; 511, one-way gear; 512, movable rod; 51 3. 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. Carrying frame; 7. Self-locking unit; 71. Mounting stand; 72. Ratchet; 73. Self-locking spring; 74. Pull rope; 75. Second guide wheel; 76. Block block; 77. L-shaped self-locking rod; 78. L-shaped unlocking rod; 79. Ratchet; 8. Iron block; 9. Permanent magnet; 10. Spray pipe; 11. Drain pipe; 12. Ventilation opening; 13. Arc-shaped limit rod; 14. Buffer spring. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] Example: Reference Figure 1-5 The alkaline vapor etching silicon carbide wafer device shown in the figure comprises an etching cylinder 3 of a cylindrical structure with a feed opening at the right end and a carrier 6 for carrying silicon carbide wafers, a heater 2 is arranged at the bottom of the etching cylinder 3, and a heat-insulating shell is arranged on the outer surface of the heater 2, and the heating chamber inside the heater 2 is communicated with the inner chamber of the etching cylinder 3 through a vent opening 12 arranged at the bottom of the inner chamber of the etching cylinder 3, and is characterized in that: it also comprises a sealing drive unit 4, an automatic liquid adding unit 5 and an atomizing cleaning and cooling unit;

[0047] Sealing drive unit 4: used to push the carrier 6 into the inner cavity of the corrosion cylinder 3 and seal the feed opening;

[0048] Automatic liquid adding unit 5: automatically and quantitatively adding an appropriate amount of alkaline solution into the heating chamber according to the amount of silicon carbide wafers placed on the carrier 6;

[0049] The carrier frame 6 is mounted on the sealing drive unit 4, and the sealing drive unit 4, the heater 2 and the automatic liquid adding unit 5 are all mounted on the support frame 1;

[0050] Atomization cleaning and cooling unit: used to clean and cool the silicon carbide wafer after etching, and also to cool and liquefy the excess alkaline vapor in the etching cylinder 3.

[0051] As a preferred implementation in this embodiment, Figure 1-5 As shown, the sealing drive unit 4 includes an L-shaped mounting frame 43 mounted on the support frame 1 and a slide rail mounted on the top of the inner cavity of the corrosion cylinder 3, an electric track 44 is mounted on the L-shaped mounting frame 43, a moving slider 45 is mounted on the electric track 44, a rotating shaft 47 is rotatably provided at the lower end of the moving slider 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 rotatably connected to the right end of the connecting slide rod 42, the left end of the connecting slide rod 42 is slidably provided on the slide rail, a first bevel gear is mounted on the right end of the rotating shaft 47, a driving motor 46 is fixed to the lower end of the moving slider 45, and a second bevel gear meshingly connected to the first bevel gear is mounted on the lower end of the driving motor 46;

[0052] The automatic liquid adding unit 5 includes a mounting groove 51 mounted at the lower end of the connecting slide rod 42 and a movable vertical rod 54 located below the carrier frame 6 and slidingly penetrating the support frame 1. A T-shaped block 52 is movably arranged in the mounting groove 51, and the T-shaped block 52 is connected to the mounting groove 51 through a plurality of linear springs 519 arranged at equal intervals. The lower end of the T-shaped block 52 passes through an opening at the bottom of the mounting groove 51 and is fixedly connected to the upper end of the carrier frame 6.

[0053] A contact plate 55 in contact with the bottom of the carrier frame 6 is fixed to the upper end of the movable vertical rod 54, and first guide wheels 57 are evenly spaced on both sides of the movable vertical rod 54. Counterweight ropes 59 are assembled and connected to the two first guide wheels 57. The ends of the counterweight ropes 59 pass through the through-holes 53 provided on the movable vertical rod 54, and the middle part of the rope body of the counterweight rope 59 is fixed in the through-holes 53. Counterweight blocks 58 of the same specifications are fixed at both ends of the counterweight rope 59. The two counterweight blocks 58 always keep the same height. A plurality of driving teeth 56 are evenly spaced from top to bottom on the front end of the movable vertical rod 54. The driving teeth 56 are toothed with the one-way gear 511, and the one-way gear 511 is fixedly sleeved on On the crankshaft 510, the crankshaft 510 is rotatably arranged on a U-shaped frame 515 arranged at the bottom of the support frame 1, and 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, and the two piston heads 513 are respectively sealed and slidably arranged in the corresponding piston cylinders 514, and the two piston cylinders 514 are communicated with the liquid storage chamber 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 chamber of the heater 2 through the liquid outlet pipe 517 arranged at the side end, and the liquid inlet one-way valve and the liquid outlet one-way valve are respectively arranged on the liquid inlet pipe 516 and the liquid outlet pipe 517;

[0054] The weight of the two counterweights 58 is greater than the overall weight of the movable upright 54;

[0055] The atomizing cleaning and cooling unit includes a spray pipe 10 with a valve on the liquid inlet end and a discharge pipe 11 which is connected to the inner cavity of the heating chamber and has a valve. A plurality of atomizing spray heads are arranged at equal intervals on the spray pipe 10, and the plurality of atomizing spray heads are all located in the inner cavity of the corrosion cylinder 3. The discharge pipe 11 is located at the bottom of the heater 2.

[0056] The heater 2 , the driving motor 46 and the electric track 44 are all electrically connected to the PLC controller on the support frame 1 .

[0057] In the initial state, the lower end of the carrier 6 just contacts the contact plate 55, and a certain number of silicon carbide wafers are placed on the carrier 6. Within the elastic range of the linear spring 519, each time a silicon carbide wafer is placed on the carrier 6, it will drop a certain distance at an equal distance. When the carrier 6 drops, part of its weight acts on the contact plate 55, so that the movable vertical rod 54 overcomes the total gravity of the two counterweights 58 and the resistance of the crankshaft 510 to rotate downward. As the movable vertical rod 54 moves downward, the driving tooth 56 is meshed with 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 cylinders 514. The alkaline solution in the liquid storage barrel 518 is pumped continuously into the heating chamber with a movement. Every time the carrier 6 drives the movable vertical rod 54 to descend a certain distance, the alkaline solution will be pumped into the heating chamber. Even if the movable vertical rod 54 descends a small distance, a corresponding amount of alkaline solution will be pumped into the heating chamber, which is conducive to the precise control of the amount of alkaline solution. When the silicon carbide wafer is placed (the height of the movable vertical rod 54 can be kept unchanged by hand until the carrier 6 is restored to its original position after corrosion), the driving motor 46 is controlled to work, and the driving motor 46 drives the rotating shaft 47 to rotate, and finally the sealing plate 41 is rotated outward by a certain angle. At this angle, when the sealing plate 41 moves horizontally, it will not contact the contact plate 55, and the angle of the sealing plate 41 is adjusted. After the section is completed, the electric rail 44 is controlled to drive the sealing plate 41 and the carrier 6 to move horizontally, that is, to move toward the inner cavity of the etching cylinder 3. When the carrier 6 is completely moved into the etching cylinder 3 and the sealing plate 41 passes over the contact plate 55, the driving motor 46 is controlled to move in the opposite direction and restore the original angle. Then, driven by the electric slide rail 44, the sealing plate 41 will form a seal with the feed opening end of the etching cylinder 3. At this time, the heater 2 is controlled to heat the alkaline solution in the heating chamber to form alkaline steam to corrode the silicon carbide wafer. After the corrosion is completed (the heater 2 stops heating at this time), the pump body is controlled to inject room temperature deionized water into the spray pipe 11 to atomize and clean the silicon carbide wafer and cool it down. At the same time, the atomization of deionized water at room temperature can effectively and comprehensively The excess unreacted alkaline vapor is cooled and condensed, so that the excess alkaline vapor is condensed into droplets and finally gathered in the heating chamber (to avoid the overflow of alkaline gas when the carrier 6 is removed). The mixed liquid (alkaline solution and deionized water cleaning liquid containing impurities) gathered in the heating chamber can be discharged through the drain pipe 11. After waiting for the cleaning droplets on the silicon carbide wafer to drip into the heating chamber, the electric track 44 and the driving motor 46 cooperate to make the carrier 6 and the sealing plate 41 (which will pass over the contact plate 55 again) return to their original positions (after returning to their original positions, the hand holding the movable upright 54 at a constant height can be released. Under the action of the gravity of the two counterweights 58, the movable upright 54 will move upward and return to its original position, and will not drive the crankshaft 510 to rotate during this process.At this time, the lower end of the counterweight block 58 will contact 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 remembering the number of silicon carbide wafers placed.

[0058] It should be noted that, Fig.10 As shown, the carrier 6 includes a plurality of arc-shaped support rods 61 arranged at equal intervals, and the plurality of arc-shaped support rods are connected by a plurality of connecting rods 62, so that 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 rods 62; secondly, the device is suitable for the automatic liquid addition operation of silicon carbide wafers of the same specification (so that the weight of each wafer is consistent), which can make the amount of alkaline solution added more accurate, and the device is also suitable for the automatic liquid addition operation of silicon carbide wafers of the same thickness and different diameters; thirdly, by setting the counterweight block, it can be ensured that the resistance encountered by the carrier 6 when it moves downward remains unchanged, and at the same time, the counterweight block 58 can offset the gravity of the movable vertical rod 54, so that the carrier 6 will be subject to less resistance when it moves downward, which is conducive to the accurate addition of alkaline solution; fourthly, the device automatically performs quantitative heating while placing the silicon carbide wafer, which can improve work efficiency.

[0059] As a preferred implementation in this embodiment, Figure 3 As shown, it also includes a self-locking unit 7, which can lock the movable upright rod 54 when the movable upright rod 54 cannot continue to move downward. After the supporting frame 6 enters the corrosion cylinder 3 and completes the processing and moves out and returns to the initial state, the movable upright rod 54 can be automatically unlocked.

[0060] The arrangement of the self-locking unit 7 allows the height of the movable upright 54 to be kept constant without manual effort during the entire corrosion process, thereby reducing the labor intensity of the operator.

[0061] As a preferred implementation in this embodiment, Figure 3 and Figure 6 As shown, the self-locking unit 7 includes a plurality of ratchets 79 arranged at the rear end of the movable upright 54 and arranged in a straight line from top to bottom, a mounting stand 71 fixed on the support frame 1, and an L-shaped unlocking rod 78 whose upper end is fixedly mounted on the lower end of the carrier frame 6. A pawl 72 adapted to the ratchet 79 is rotatably provided at the front end of the mounting stand 71. 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 is finally fixedly connected to 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.

[0062] When the movable vertical rod 54 can no longer move downward, the cooperation between the pawl 72 and the ratchet 79 prevents the movable vertical rod 54 from moving upward under the gravity of the counterweight 58. At this time, the movable vertical rod 54 is locked. When the carbide wafers on the carrier frame 6 are restored to their original positions after corrosion treatment, the silicon carbide wafers on the carrier frame 6 can be removed. As the silicon carbide wafers are removed one by one, under the action of the linear spring 519, the carrier frame 6 drives the L-shaped unlocking rod 78 to gradually rise in height. When all the silicon carbide wafers on the carrier frame 6 are removed, the L-shaped unlocking rod 78 will contact the L-shaped self-locking rod 77 and drive it to move upward a distance. Since the L-shaped self-locking rod 77 moves upward for a distance, the pull rope 74 will cause the pawl 72 to compress the self-locking spring 73, thereby releasing the self-locking state of the pawl 72 and the ratchet 79. Under the gravity of the counterweight 58, the movable vertical rod 54 returns to its original position. The arrangement of the self-locking unit 7 allows the height of the movable upright 54 to be kept constant without manual effort during the entire corrosion process, thereby reducing the labor intensity of the operator.

[0063] It should be noted that the weight of the etched silicon carbide wafer is lower than the weight of the untreated silicon carbide wafer, so the lower end of the carrier 6 loaded with the etched wafer is located above the lower end of the carrier 6 when the wafer is untreated.

[0064] As a preferred implementation in this embodiment, Figure 7 As shown, the pawl 72 includes a first part and a second part, the first part and the second part are connected by a buffer spring 14, an arc-shaped limit rod 13 consistent with the movement path of the first part is fixedly provided on the first part, and the arc-shaped limit rod 13 is slidably arranged in the inner cavity of the second part away from the end of the first part.

[0065] The pawl 72 is configured as two parts and connected by a buffer spring 14. When the pawl 72 rotates around the rotating shaft under the action of the pulling force of the pull rope 74, a downward force will be generated on the ratchet 79. At this time, the arc-shaped limit rod 13 on the first part can move toward the inner cavity of the second part (at this time, the movement of the compression buffer spring 14 is also performed), thereby buffering the force on the ratchet 79, thereby avoiding the movable vertical rod 54 from moving downward when the self-locking of the pawl 72 and the ratchet 79 is released (when the movable vertical rod 54 moves downward, the alkaline solution in the liquid storage barrel 518 will be pumped into the heating chamber, causing unnecessary waste of alkaline solution), and also avoiding the situation where the L-shaped unlocking rod 78 needs to exert a large upward force on the L-shaped self-locking rod 77 to release the self-locking state.

[0066] As a preferred implementation manner in this embodiment, an auxiliary unit is also included to assist the movable upright rod 54 to overcome the resistance encountered when the driving crankshaft 510 rotates.

[0067] Due to the existence of resistance, when a small number of chips, such as one chip, are placed on the carrier 6, it is easy for the movable upright 54 to descend too short a distance, resulting in too little alkaline solution being added to the heating chamber, and the chips cannot be well corroded. Therefore, an auxiliary unit is provided to overcome the resistance encountered when the driving crankshaft 510 rotates, so that an appropriate amount of alkaline solution can be added to the heating chamber.

[0068] As a preferred implementation in this embodiment, Figure 8 and Fig. 9 As shown, the auxiliary unit includes a plurality of iron blocks 8 installed on the upper end of a T-shaped block 52 and arranged at equal intervals, the lower ends of the plurality of iron blocks 8 are slidably arranged in the inner cavity of the T-shaped block 52, and permanent magnets 9 are fixed on the inner cavity parts of the mounting grooves 51 corresponding to the plurality of iron blocks 8. In the initial state, that is, when no silicon carbide wafer is placed on the carrier frame 6, the plurality of permanent magnets 9 are adsorbed and fixed to 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 gravity of the plurality of iron blocks 8.

[0069] At the beginning, through the magnetic attraction between 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 multiple iron blocks 8 does not act on the linear spring 519 (the sum of the weights of the multiple iron blocks 8 is equal to the resistance encountered when the crankshaft 510 is driven to rotate. In this state, the accuracy of automatic addition of the alkaline solution will be further improved). When a chip is placed on the carrier 6, under the action of its gravity, the permanent magnet 9 and the iron block 8 are separated to produce a gap (the magnetic force between the permanent magnet 9 and the iron block 8 is related to the distance between them. When the distance between the two becomes larger, the magnetic force will rapidly decrease), the magnetic force is weakened, and finally the weight of the carrier 6, the single chip and the weight of the multiple iron blocks all act on the linear spring 519 (at this time, there is no magnetic effect on the iron block 8), thereby making the movable upright 54 Under the action of the support frame 6, it moves downward for a large distance (this distance is compared with the case where the permanent magnet 9 and the iron block 8 are not set). Even for the corrosion of a single chip, an appropriate amount of alkaline solution can be added to the heating chamber, and chips can continue to be added to the support frame 6. Within the elastic range of the linear spring 519, each time a chip is added, the support frame 6 drives the movable vertical rod 54 to drop a certain distance at equal intervals, and then an equal amount of alkaline solution is added to the heating chamber. Multiple chips can be placed on the support frame 6. With the permanent magnet 9 and the iron block 8, the accuracy of the amount of alkaline solution added can be further improved compared with the case where the permanent magnet 9 and the iron block 8 are not set. After the corrosion is completed, all the silicon carbide chips on the support frame 6 are removed. When the support frame 6 rises to a certain height and cannot continue to rise, the iron block 8 moves upward relative to the support frame 6 through the action of magnetic force, and contacts with the permanent magnet 9 to be adsorbed and fixed.

[0070] 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 guide holes are provided on the side end of the T-shaped block 52, and the plurality of guide holes are respectively communicated with the corresponding chute inner cavity accommodating the iron block 8, so that the liquid inside the chute can be discharged through the guide holes, thereby avoiding increasing the overall weight of the carrier frame 6 and avoiding affecting the accuracy of subsequent alkali solution addition.

[0071] An operating method for an alkaline vapor etching silicon carbide wafer device comprises the following steps:

[0072] S1: Manual loading and quantitative automatic liquid addition, placing silicon carbide wafers one by one on the carrier 6, within the elastic range of the linear spring 519, each time a silicon carbide wafer is added, the carrier 6 moves downward by a certain distance, as the silicon carbide wafers continue to increase, the carrier 6 contacts the contact plate 55 and drives the movable vertical rod 54 to move downward, and the alkaline solution stored in the liquid storage barrel 518 is continuously pumped into the heating chamber through the movement of the piston until the silicon carbide wafers are placed, and the liquid addition stops;

[0073] S2: feeding and sealing, controlling the driving motor 46 and the electric track 44 to work, moving the slider 45 to drive the carrier 6 and the sealing plate 41 to move toward the inner cavity of the etching cylinder 3, and at the same time, the driving motor 46 drives the rotating shaft 47 to rotate, and drives the sealing plate 41 to rotate a certain angle through the rotating shaft 47 and then stops moving, and after the sealing plate 41 passes over the contact plate 55, the driving motor 46 rotates in the direction and returns to its original position, and the sealing plate 41 continues to move close to the etching cylinder 3 and finally completes the sealing of the etching cylinder 3, at this time, the carrier 6 moves to the inner cavity of the etching cylinder 3, and controls the heater 2 to work, and heats the alkaline solution in the heating chamber, so that it vaporizes to form alkaline steam to process the silicon carbide wafer;

[0074] S3: cleaning and cooling. After the alkaline steam has completed the etching treatment of the silicon carbide wafer, deionized water at room temperature is injected into the spray pipe 10 through the pump body to perform atomized spray cleaning on the silicon carbide wafer. At the same time, atomization can quickly cool down the excess alkaline steam and air in the etching cylinder 3, and finally liquefy the steam and gather it in the heating chamber. The cleaning liquid can be discharged through the drain pipe 11. After cleaning, the carrier 6 remains stationary in the etching cylinder 3 for a period of time, and waits for the droplets on the wafer to fall into the heating chamber, and then controls the electric track 44 and the drive motor 46 to work, so that the carrier 6 and the sealing plate 41 return to their original positions.

[0075] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An alkaline vapor etching device for silicon carbide wafers, comprising an etching cylinder (3) with a feeding opening at the right end and a cylindrical structure and a carrier (6) for carrying silicon carbide wafers, characterized in that: It also includes a sealing drive unit (4) and an automatic liquid adding unit (5); A sealing drive unit (4): used to push the carrier (6) into the inner cavity of the corrosion cylinder (3) and then seal the feed opening; An automatic liquid adding unit (5) is configured to automatically and quantitatively add an appropriate amount of alkaline solution to the heating chamber of the etching cylinder (3) according to the number of silicon carbide wafers placed on the carrier (6); The bearing frame (6) is mounted on the sealing drive unit (4), and the sealing drive unit (4) and the automatic liquid adding unit (5) are both mounted on the supporting frame (1); The automatic liquid adding unit (5) comprises a mounting groove (51) mounted at the lower end of the connecting slide rod (42) and a movable vertical rod (54) located below the supporting frame (6) and slidingly passing through the supporting frame (1); a T-shaped block (52) is movably arranged in the mounting groove (51), and the T-shaped block (52) is connected to the mounting groove (51) via a plurality of linear springs (519) arranged at equal intervals; the lower end of the T-shaped block (52) passes through an opening provided at the bottom of the mounting groove (51) and is fixedly connected to the upper end of the supporting frame (6); A contact plate (55) in contact with the bottom of the support frame (6) is fixed at the upper end of the movable upright pole (54), first guide wheels (57) are evenly spaced on both sides of the movable upright pole (54), and counterweight ropes (59) are mounted and connected to the two first guide wheels (57). The ends of the counterweight ropes (59) pass through a through hole (53) provided on the movable upright pole (54), and the middle of the rope body of the counterweight rope (59) is fixed in the through hole (53). Counterweight blocks (58) of the same specification are fixed at both ends of the counterweight rope (59), and the two counterweight blocks (58) always maintain the same height. A plurality of driving teeth (56) are evenly spaced from top to bottom on the front end of the movable upright pole (54), and the driving teeth (56) are tooth-connected with a one-way gear (511). The one-way gear (511) is connected to the one-way gear (511). 511) is fixedly sleeved on the crankshaft (510), and the crankshaft (510) is rotatably arranged on a U-shaped frame (515) arranged at the bottom of the support frame (1), and two movable rods (512) are movably arranged on the crankshaft (510), and the lower ends of the two movable rods (512) are movably connected to the corresponding piston heads (513), and the two piston heads (513) are respectively sealed and slidably arranged in the corresponding piston cylinders (514), and the two piston cylinders (514) are communicated with the liquid storage chamber of the liquid storage barrel (518) through the liquid inlet pipes (516) arranged at the lower ends, and the two piston cylinders (514) are communicated with the heating chamber through the liquid outlet pipes (517) arranged at the side ends, and the liquid inlet one-way valve and the liquid outlet one-way valve are respectively arranged on the liquid inlet pipe (516) and the liquid outlet pipe (517); The weight of the two counterweight blocks (58) is greater than the overall weight of the movable upright pole (54).

2. The alkaline vapor etching silicon carbide wafer device according to claim 1, characterized in that: The sealing drive unit (4) comprises an L-shaped mounting frame (43) mounted on the support frame (1) and a slide rail mounted on the top of the inner cavity of the corrosion cylinder (3); an electric track (44) is mounted on the L-shaped mounting frame (43); a movable slider (45) is mounted on the electric track (44); a rotating shaft (47) is rotatably provided at the lower end of the movable slider (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 rotatably connected to the right end of the connecting slide rod (42); the left end of the connecting slide rod (42) is slidably provided on the slide rail; a first bevel gear is mounted on the right end of the rotating shaft (47); a driving motor (46) is fixed to the lower end of the movable slider (45); and a second bevel gear meshingly connected to the first bevel gear is mounted on the lower end of the driving motor (46); A heater (2) is provided at the bottom of the corrosion cylinder (3), and a heat-insulating shell is provided on the outer surface of the heater (2); a heating chamber inside the heater (2) is communicated with the inner chamber of the corrosion cylinder (3) through a ventilation opening (12) provided at the bottom of the inner chamber of the corrosion cylinder (3); the heater (2), the drive motor (46) and the electric track (44) are all electrically connected to a PLC controller on the support frame (1); It also includes an atomization cleaning and cooling unit, which is used to clean and cool the etched silicon carbide wafer, and also cool and liquefy the excess alkaline steam in the etching cylinder (3); The atomizing cleaning and cooling unit comprises a spray pipe (10) with a valve on the liquid inlet end and a liquid discharge pipe (11) communicating with the inner cavity of the heating chamber and having a valve, a plurality of atomizing spray heads being arranged at equal intervals on the spray pipe (10), and the plurality of atomizing spray heads are all located in the inner cavity of the corrosion cylinder (3), and the liquid discharge pipe (11) is located at the bottom of the heater (2).

3. The alkaline vapor etching silicon carbide wafer device according to claim 1, characterized in that: It also includes a self-locking unit (7) which can lock the movable upright rod (54) when the movable upright rod (54) cannot continue to move downward, and can automatically release the lock on the movable upright rod (54) after the support frame (6) enters the corrosion cylinder (3) to complete the treatment and moves out to restore the initial state.

4. The alkaline vapor etching silicon carbide wafer device according to claim 3, characterized in that: The self-locking unit (7) comprises a plurality of ratchets (79) arranged at the rear end of the movable upright rod (54) and arranged in a straight line from top to bottom, a mounting frame (71) fixed on the support frame (1), and an L-shaped unlocking rod (78) whose upper end is fixedly mounted on the lower end of the bearing frame (6); a ratchet (72) adapted to the ratchet (79) is rotatably arranged at the front end of the mounting frame (71); a movable end of the ratchet (72) is connected to the mounting frame (71) via a self-locking spring (73); A second guide wheel (75) is installed on the rear end of the stand (71), a pull rope (74) is fixed on the movable end of the ratchet (72), and 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), and the L-shaped self-locking rod (77) is provided with a blocking block (76) larger than the through hole on the horizontal plate.

5. The alkaline vapor etching silicon carbide wafer device according to claim 4, characterized in that: The pawl (72) comprises a first part and a second part, the first part and the second part are connected via a buffer spring (14), an arc-shaped limit rod (13) which is consistent with the movement path of the first part is fixedly arranged on the first part, and the arc-shaped limit rod (13) is slidably arranged in the inner cavity of the second part away from the end of the first part.

6. The alkaline vapor etching silicon carbide wafer device according to claim 1, characterized in that: It also includes an auxiliary unit, which is used to assist the movable upright rod (54) in overcoming the resistance encountered when driving the crankshaft (510) to rotate.

7. The alkaline vapor etching silicon carbide wafer device according to claim 6, characterized in that: The auxiliary unit comprises a plurality of iron blocks (8) mounted on the upper end of the T-shaped block (52) and arranged at equal intervals, the lower ends of the plurality of iron blocks (8) are slidably arranged in the inner cavity of the T-shaped block (52), and permanent magnets (9) are fixed on the inner cavity parts of the mounting grooves (51) corresponding to the plurality of iron blocks (8). In an initial state, i.e., when no silicon carbide wafer is placed on the carrier (6), the plurality of permanent magnets (9) are adsorbed and fixed to the corresponding iron blocks (8), the linear spring (519) is in a compressed state, and 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 weight of a single silicon carbide wafer, and the sum of the magnetic forces is greater than the sum of the weights of the plurality of iron blocks (8).

8. The method for operating an alkaline vapor etching silicon carbide wafer device according to any one of claims 1 to 7, characterized in that: The steps include: S1: Manual loading and quantitative automatic liquid addition, silicon carbide wafers are placed one by one on the carrier (6), and within the elastic range of the linear spring (519), each time a silicon carbide wafer is added, the carrier (6) moves downward a certain distance. As the silicon carbide wafers continue to increase, the carrier (6) contacts the contact plate (55) and drives the movable vertical rod (54) to move downward, and the alkaline solution stored in the liquid storage barrel (518) is continuously pumped into the heating chamber through the movement of the piston until the silicon carbide wafers are placed, and the liquid addition stops; S2: feeding and sealing, controlling the driving motor (46) and the electric track (44) to work, moving the slider (45) to drive the carrier (6) and the sealing plate (41) to move toward the inner cavity of the etching cylinder (3), and at the same time, the driving motor (46) drives the rotating shaft (47) to rotate, and drives the sealing plate (41) to rotate a certain angle through the rotating shaft (47) and then stop moving. After the sealing plate (41) passes over the contact plate (55), the driving motor (46) rotates in the direction and returns to its original position, and the sealing plate (41) continues to move closer to the etching cylinder (3) and finally completes the sealing of the etching cylinder (3). At this time, the carrier (6) moves to the inner cavity of the etching cylinder (3), and the heater (2) is controlled to work to heat the alkaline solution in the heating chamber, so that it vaporizes to form alkaline steam to process the silicon carbide wafer; S3: cleaning and cooling. After the alkaline steam has been used to corrode the silicon carbide wafer, deionized water at room temperature is injected into the spray pipe (10) through the pump body to perform atomized spray cleaning on the silicon carbide wafer. At the same time, atomization can quickly cool down the excess alkaline steam and air in the corrosion cylinder (3), and finally liquefy the steam and gather it in the heating chamber. The cleaning liquid can be discharged through the drain pipe (11). After cleaning, the support frame (6) is stationary in the corrosion cylinder (3) for a period of time, and the droplets on the wafer fall into the heating chamber. Then, the electric track (44) and the drive motor (46) are controlled to work, so that the support frame (6) and the sealing plate (41) return to their original positions.

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