Monocrystalline silicon sample corrosion system and corrosion process thereof

Abstract

The invention relates to the technical field of monocrystalline silicon corrosion treatment, in particular to a monocrystalline silicon sample corrosion system and a corrosion process thereof, the corrosion system comprises a corrosion tank, a material carrying box and a cover plate, the corrosion tank is filled with corrosion liquid, and the corrosion tank is divided into an inner tank and an outer tank. The device is provided with the inner tank, the outer tank and the material carrying box, during corrosion operation, a corrosion liquid in the outer tank directionally flows into the inner tank, and the corrosion liquid in the inner tank flows from bottom to top, so that the corrosion liquid reacted with a monocrystalline silicon sample and a reaction product flow from bottom to top, and the corrosion liquid is separated from the reaction product. By controlling the immersion time of the monocrystalline silicon sample in the corrosive liquid, the corrosive liquid around the monocrystalline silicon sample is ensured not to react with the monocrystalline silicon sample all the time, so that the concentration of the corrosive liquid around the monocrystalline silicon sample is ensured to be unchanged as far as possible, the corrosion speed of the corrosive liquid can be accurately predicted, and the corrosion speed of the monocrystalline silicon sample can be accurately predicted by controlling the immersion time of the monocrystalline silicon sample in the corrosive liquid. Therefore, the corrosion depth and the surface appearance of the surface of the monocrystalline silicon sample can be accurately controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of single-crystal silicon etching treatment, and particularly to a single-crystal silicon sample etching system and an etching process thereof. Background Art

[0002] A single-crystal silicon wafer is a thin wafer made of single-crystal silicon. Single-crystal silicon has a highly ordered atomic structure, which makes it excellent in electronic properties and is widely used in the manufacture of various semiconductor devices, such as integrated circuits. During the cutting and grinding processes of the single-crystal silicon wafer, an inevitable damage layer will be formed on the surface of the wafer. These damages will seriously affect the electrical properties of the wafer and may lead to the failure of subsequent processes. And through etching, these damage layers can be effectively removed to restore the high-quality crystal structure on the surface of the wafer.

[0003] In the existing silicon wafer etching technologies, the most common one is the wet etching technology. During specific operations, the silicon wafer is placed in the etching solution, and through the chemical reaction between the etching solution and the silicon wafer, the defects on the surface of the silicon wafer are removed. However, the following problems exist in the above etching process: the substances etched off from the silicon wafer (such as hexafluorosilicic acid, silicate, etc.) dissolve in the etching solution, and the existence of these substances will cause continuous interference to the etching, resulting in the consumption of the effective components (such as HNO3, HF, KOH, etc.) in the etching solution, and the concentration of the etching solution decreases, thereby making it difficult to precisely control the etching depth and surface topography of the silicon wafer surface. Summary of the Invention

[0004] Based on this, it is necessary to provide a single-crystal silicon sample etching system and an etching process thereof for the problems existing in the current silicon wafer etching equipment, so as to solve the problem of difficult precise control of the etching depth and surface topography of the silicon wafer surface.

[0005] The above object is achieved by the following technical solutions: A single-crystal silicon sample etching system includes: An etching tank, the etching tank is filled with an etching solution. The etching tank is divided into an inner tank and an outer tank. The tops of both the inner tank and the outer tank are open. A liquid discharge port is provided in the upper part of the inner tank, and a communication hole is provided in the lower part of the inner tank; A loading box, the loading box can move vertically. The loading box is used to place a single-crystal silicon sample. The loading box is located inside the inner tank and the outer side wall of the loading box is slidably sealed with the inner tank; A cover plate, the cover plate can move vertically, and the cover plate is located inside the outer tank and is slidably sealed with the outer tank; During the etching operation, the material carrier moves vertically downward, causing the etching solution inside the inner groove to flow directionally through the communication holes into the outer groove. When the material carrier moves vertically until its interior is in communication with the communication holes, the material carrier stops moving downward. At this time, the cover plate moves vertically downward, causing the etching solution inside the outer groove to flow directionally into the material carrier through the communication holes. At the same time, by suction through the liquid discharge port, the etching solution flowing into the material carrier moves directionally from bottom to top.

[0006] Preferably, a first driving assembly is provided outside the etching tank, and the first driving assembly is used to drive the cover plate to move in the vertical direction. The first driving assembly includes a first linear driving element, a connecting frame, and a first connecting plate. The first linear driving element is arranged outside the etching tank. The connecting frame is fixedly connected to the power end of the first linear driving element. The upper end of the first connecting plate is fixedly connected to the connecting frame, and the lower end of the first connecting plate is fixedly connected to the upper surface of the cover plate.

[0007] Preferably, a second driving assembly is further provided outside the etching tank, and the second driving assembly is used to drive the material carrier to move in the vertical direction. The second driving assembly includes a second linear driving element, an intermediate plate, and a second connecting plate. The second linear driving element is arranged outside the etching tank. The intermediate plate is fixedly connected to the power end of the second linear driving element. The upper end of the second connecting plate is fixedly connected to the intermediate plate, and the lower end of the second connecting plate is fixedly connected to the outer side surface of the material carrier.

[0008] Preferably, a rotating disk is rotatably arranged inside the material carrier. The axis of the rotating disk is horizontal, and a plurality of material clamping jigs are equidistantly arranged in the circumferential direction of the rotating disk. The material clamping jigs are used to clamp single-crystal silicon samples.

[0009] Preferably, a third driving assembly is provided between the rotating disk and the intermediate plate, and the third driving assembly is used to drive the rotating disk to rotate slowly around its own axis.

[0010] Preferably, the third driving assembly includes a motor, a long shaft, a central shaft, and a conical transmission disk. The motor is arranged on the intermediate plate. The output shaft of the motor is coaxially and fixedly connected to the long shaft. A conical transmission surface is provided at one end of the long shaft away from the motor. The central shaft is coaxially arranged at one end of the rotating disk and rotatably passes through the side surface of the material carrier. The conical transmission disk is in transmission cooperation with the conical transmission surface.

[0011] Preferably, the material loading fixture includes a connecting rod, an outer clamping plate, an inner clamping plate, and a right clamping block. One end of the connecting rod is provided on the side wall of the material loading box. The inner clamping plate is fixedly connected to the end of the connecting rod away from the material loading box. The outer clamping plate is elastically slidably connected to the outside of the inner clamping plate, and the outer clamping plate can move relative to the inner clamping plate along the axis of the corresponding connecting rod. There are multiple right clamping blocks, and the multiple right clamping blocks are arranged at equal intervals along the axis of the corresponding connecting rod on the upper surface and the lower surface inside the outer clamping plate. The left clamping blocks are arranged at equal intervals along the axis of the corresponding connecting rod on the upper surface and the lower surface inside the inner clamping plate; When the outer clamping plate moves relative to the inner clamping plate along the axis of the corresponding connecting rod, the left clamping block and the right clamping block move away from each other.

[0012] Preferably, a fourth driving assembly is provided between the connecting rod and the material loading box, and the fourth driving assembly is used to drive the connecting rod to rotate around its axis.

[0013] Preferably, the fourth driving assembly includes a planetary gear and an external gear ring. There are multiple planetary gears, and the multiple planetary gears correspond to multiple central shafts one by one, and the planetary gears are coaxially and fixedly connected to the central shafts. The external gear ring is arranged on the inner side wall of the material loading box, and the external gear ring meshes with the planetary gears.

[0014] A single crystal silicon sample etching process uses the single crystal silicon sample etching system described in any one of the above.

[0015] The beneficial effects of the present invention are: The present invention is provided with an inner groove, an outer groove, and a material loading box. During the etching operation, the etching solution in the outer groove is directed to flow into the inner groove, and the etching solution in the inner groove flows from bottom to top, so that the etching solution after reacting with the single crystal silicon sample together with the reaction products flows from bottom to top, ensuring that the etching solution around the single crystal silicon sample is always the etching solution that has not reacted with the single crystal silicon sample, thereby ensuring that the concentration of the etching solution around the single crystal silicon sample remains as constant as possible, and further ensuring that the etching rate of the etching solution can be accurately predicted. In this way, by controlling the immersion time of the single crystal silicon sample in the etching solution, the etching depth and surface morphology of the single crystal silicon sample surface can be accurately controlled. Description of the Drawings

[0016] Figure 1 It is an overall schematic diagram of a single crystal silicon sample etching system of the present invention; Figure 2 It is a structural schematic diagram of the first driving assembly in a single crystal silicon sample etching system of the present invention; Figure 3 It is a structural schematic diagram of the liquid replenishing port in a single crystal silicon sample etching system of the present invention; Figure 4 It is a structural schematic diagram of the inner groove and the outer groove in a single crystal silicon sample etching system of the present invention; Figure 5 Schematic structural diagram of the loading fixture in a single-crystal silicon sample etching system of the present invention; Figure 6 Schematic structural diagram of the third driving component and the fourth driving component in a single-crystal silicon sample etching system of the present invention; Figure 7 Schematic structural diagram of the loading cassette in a single-crystal silicon sample etching system of the present invention; Figure 8 Exploded view of the third driving component in a single-crystal silicon sample etching system of the present invention; Figure 9 is Figure 8 Schematic diagram of the enlarged structure at position A in Figure 10 Exploded view of the loading fixture in a single-crystal silicon sample etching system of the present invention.

[0017] Wherein: 100, etching tank; 110, inner tank; 111, liquid discharge port; 112, communication hole; 120, outer tank; 121, liquid replenishment port; 130, cover plate; 200, loading cassette; 210, rotating disk; 220, through hole; 300, first driving component; 310, first linear driving element; 320, connecting frame; 330, first connecting plate; 400, second driving component; 410, second linear driving element; 420, intermediate plate; 430, second connecting plate; 500, loading fixture; 510, connecting rod; 520, outer clamping plate; 530, inner clamping plate; 540, right clamping block; 550, left clamping block; 600, third driving component; 610, motor; 620, long shaft; 621, conical transmission surface; 630, central shaft; 640, conical transmission disk; 700, fourth driving component; 710, planetary gear; 720, external gear ring; 800, single-crystal silicon sample. Detailed implementation manners

[0018] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] The serial numbers assigned to the components in this document itself, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meaning. The "connection" and "coupling" mentioned in this invention, unless otherwise specified, both include direct and indirect connection (coupling). In the description of this invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to this invention.

[0020] In this invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0021] As Figures 1 to 10 shown, a single-crystal silicon sample etching system includes an etching tank 100, a loading box 200, and a cover plate 130. The etching tank 100 contains an etching solution. The etching tank 100 is divided into an inner tank 110 and an outer tank 120. The tops of both the inner tank 110 and the outer tank 120 are open. A liquid discharge port 111 is provided in the upper part of the inner tank 110, and a communication hole 112 is provided in the lower part of the inner tank 110. The loading box 200 can move in the vertical direction. The loading box 200 is used to place a single-crystal silicon sample 800. The loading box 200 is located inside the inner tank 110, and the outer sidewall of the loading box 200 is slidably sealed with the inner tank 110. The cover plate 130 can move in the vertical direction, and the cover plate 130 is located inside the outer tank 120 and is slidably sealed with the outer tank 120. During the etching operation, the loading box 200 moves vertically downward, so that the etching solution inside the inner tank 110 flows directionally through the communication hole 112 into the outer tank 120. When the loading box 200 moves vertically until its inside is in communication with the communication hole 112, the loading box 200 stops moving downward. At this time, the cover plate 130 moves vertically downward, so that the etching solution inside the outer tank 120 flows directionally into the loading box 200 through the communication hole 112. At the same time, through suction by the liquid discharge port 111, the etching solution flowing into the loading box 200 flows directionally from bottom to top.

[0022] It should also be added that in order to enable the etching solution inside the outer groove 120 to flow into the loading box 200 in a directional manner through the communication holes 112 when the loading box 200 moves vertically downward to a preset position. Specifically, a plurality of through holes 220 are circumferentially and evenly formed in the lower side of the loading box 200. In this way, when the loading box 200 moves vertically downward until the through holes 220 thereon and the communication holes 112 at the lower part of the inner groove 110 are at the same height position, the through holes 220 and the communication holes 112 are communicated. At this time, the etching solution inside the outer groove 120 can enter the inside of the loading box 200 through the communication holes 112 and the through holes 220 in sequence.

[0023] In the initial state, the etching tank 100 is filled with etching solution inside. Since the lower parts of the inner tank 110 and the outer tank 120 are connected by the communication hole 112, the liquid levels in the inner tank 110 and the outer tank 120 are the same. At this time, the loading box 200 is located above the liquid level of the etching solution. The loading box 200 contains the single-crystalline silicon sample 800 to be etched, and the surface of the single-crystalline silicon sample 800 to be etched is exposed. The surface of the single-crystalline silicon sample 800 that does not need to be processed is wrapped with a protective film. During the etching operation, the staff moves the loading box 200 vertically downward. When the lower bottom surface of the loading box 200 contacts the liquid level of the etching solution, the loading box 200 pushes the etching solution in the inner tank 110, causing the liquid level of the etching solution in the inner tank 110 to drop. At this time, the etching solution in the inner tank 110 enters the inside of the outer tank 120 through the communication hole 112, causing the liquid level of the etching solution in the outer tank 120 to rise. When the loading box 200 is vertically moved downward to a position where the communication hole 112 and the through hole 220 on the side surface of the loading box 200 are at the same height, the communication hole 112 and the through hole 220 are in a communicating state. At this time, under the action of the liquid level difference, the etching solution inside the outer tank 120 sequentially flows into the inside of the loading box 200 through the communication hole 112 and the through hole 220 to immerse and etch the single-crystalline silicon sample 800 inside the loading box 200. To accelerate the directional flow rate of the etching solution, at this time, the staff moves the cover plate 130 vertically downward, thereby pushing the liquid level of the etching solution in the outer tank 120 to drop rapidly and increasing the directional flow rate of the etching solution. At the same time, the staff sucks the etching solution in the inner tank 110 through the pump connected to the drain port 111, causing the etching solution in the inner tank 110 to flow directionally from bottom to top. Specifically, the drain port 111 can be connected to the input end of the pump, so that the etching solution in the inner tank 110 can flow from bottom to top, causing the etching solution after reacting with the single-crystalline silicon sample 800 and the reaction products to flow from bottom to top, ensuring that the etching solution around the single-crystalline silicon sample 800 is always the etching solution that has not reacted with the single-crystalline silicon sample 800, thereby ensuring that the concentration of the etching solution around the single-crystalline silicon sample 800 remains as unchanged as possible, and further ensuring that the etching rate of the etching solution can be accurately predicted. In this way, by controlling the immersion time of the single-crystalline silicon sample 800 in the etching solution, the etching depth and surface morphology of the surface of the single-crystalline silicon sample 800 can be accurately controlled.

[0024] It should also be supplemented that before the material loading box 200 is immersed in the etching solution, the etching solution in the inner tank 110 is squeezed by the bottom surface of the material loading box 200 and enters the outer tank 120, causing the liquid level in the outer tank 120 to be higher than that in the inner tank 110. At this time, the etching solution in the outer tank 120 surrounds the periphery of the material loading box 200. In addition, the etching solution in the inner tank 110 is located at the bottom of the material loading box 200. Therefore, it can form a temperature wrap for the single crystal silicon sample 800 in the material loading box 200, preheat the single crystal silicon sample in the material loading box 200, and reduce the temperature difference between the single crystal silicon sample 800 and the etching solution.

[0025] It should also be noted that the existing etching tank 100 for containing the etchant usually has an open-top shape. The etching solution near the liquid level of the etching solution is extremely likely to undergo an oxidation reaction with the air. This will cause the single crystal silicon sample 800 to inevitably come into contact with this part of the etching solution when the single crystal silicon sample 800 is placed down. And this part of the etching solution has an unpredictable concentration due to its oxidation reaction, which will cause the etching depth and surface morphology of the surface of the single crystal silicon sample 800 to become uncontrollable. To solve this problem, the present invention provides a cover plate 130 to seal the opening of the outer tank 120, and makes the lower surface of the material loading box 200 slide-sealed with the peripheral wall of the inner tank 110. In this way, before the etching solution enters the inside of the material loading box 200, the etching solution inside the etching tank 100 will not come into contact with the outside air, thus reducing the possibility of the etching solution being oxidized.

[0026] It should also be supplemented that when the etching solution inside the outer tank 120 enters the inside of the material loading box 200 and the liquid level height in the inner tank 110 is lower than the height of the liquid discharge port 111, the etching solution in the inner tank 110 can no longer stably move upward directionally from bottom to top. To solve this problem, a flexible tube can be inserted into the liquid discharge port 111, and a lightweight plastic floating ball is provided at the end of the flexible tube away from the liquid discharge port 111. In this way, the plastic floating ball always floats at the liquid level position in the inner tank 110. In this way, when the liquid level height in the inner tank 110 is lower than the height of the liquid discharge port 111, it can also ensure that the etching solution in the inner tank 110 flows upward directionally from bottom to top.

[0027] In this embodiment, as Figure 2 shown, a first driving assembly 300 is provided outside the etching tank 100. The first driving assembly 300 is used to drive the cover plate 130 to move in the vertical direction. The first driving assembly 300 includes a first linear driving element 310, a connecting frame 320, and a first connecting plate 330. The first linear driving element 310 is arranged outside the etching tank 100. The connecting frame 320 is fixedly connected to the power end of the first linear driving element 310. The upper end of the first connecting plate 330 is fixedly connected to the connecting frame 320, and the lower end of the first connecting plate 330 is fixedly connected to the upper surface of the cover plate 130.

[0028] When the staff needs the cover plate 130 to move in the vertical direction, the power end of the first linear driving element 310 drives the connecting frame 320 to move synchronously. The connecting frame 320 drives the first connecting plate 330 to move synchronously, and the first connecting plate 330 drives the cover plate 130 to move synchronously.

[0029] It should also be supplemented that the first linear driving element 310 is specifically an electric telescopic rod, a cylinder or a screw slider mechanism. Taking the first linear driving element 310 as a screw slider mechanism as an example, there are two screw slider mechanisms. The two screw slider mechanisms are located on the left and right sides of the corrosion tank 100. The screws are vertically arranged outside the corrosion tank 100, the axes of the screws are vertical, and the screws are threadedly connected to the connecting frame 320. One end of the screw is fixedly connected with a servo motor. To install the servo motor, a support frame also needs to be arranged outside the corrosion tank 100, and the servo motor is arranged on the support frame.

[0030] In this embodiment, as Figure 1 shown, a second driving assembly 400 is further arranged outside the corrosion tank 100. The second driving assembly 400 is used to drive the material loading box 200 to move in the vertical direction. The second driving assembly 400 includes a second linear driving element 410, an intermediate plate 420 and a second connecting plate 430. The second linear driving element 410 is arranged outside the corrosion tank 100. The intermediate plate 420 is fixedly connected to the power end of the second linear driving element 410. The upper end of the second connecting plate 430 is fixedly connected to the intermediate plate 420, and the lower end of the second connecting plate 430 is fixedly connected to the outer side surface of the material loading box 200.

[0031] When the staff needs the material loading box 200 to move in the vertical direction, the power end of the second linear driving element 410 drives the intermediate plate 420 to move synchronously. The intermediate plate 420 drives the second connecting plate 430 to move synchronously, and the second connecting plate 430 drives the material loading box 200 to move synchronously.

[0032] It should also be supplemented that the second linear driving element 410 is specifically any one of an electric telescopic rod, a cylinder or a screw slider mechanism. Taking the second linear driving element 410 as a screw slider mechanism as an example, there are two screw slider mechanisms. The two screw slider mechanisms are located on the front and back sides of the corrosion tank 100. The screws are vertically arranged outside the corrosion tank 100, the axes of the screws are vertical, and the screws are threadedly connected to the intermediate plate 420. One end of the screw is fixedly connected with a servo motor. To install the servo motor, a support frame also needs to be arranged outside the corrosion tank 100, and the servo motor is arranged on the support frame.

[0033] In this embodiment, as Figure 5 and Figure 6As shown, a rotating disk 210 is rotatably arranged inside the material loading box 200. The axis of the rotating disk 210 is horizontal, and a plurality of material loading jigs 500 are circumferentially and equidistantly arranged on the rotating disk 210. The material loading jigs 500 are used to clamp the single crystal silicon samples 800.

[0034] After the material loading box 200 is immersed in the etching solution, the material loading jigs 500 together with the single crystal silicon samples 800 they clamp enter the etching solution. At this time, the operator rotates the rotating disk 210 around its own axis. Since the plurality of material loading jigs 500 are circumferentially and equidistantly arranged on the rotating disk 210, as the rotating disk 210 rotates circumferentially, the material loading jigs 500 that enter the etching solution first together with the single crystal silicon samples 800 they clamp are removed from the etching solution first, and the material loading jigs 500 that enter the etching solution later together with the single crystal silicon samples 800 they clamp are removed from the etching solution later, so as to ensure that the time lengths for the single crystal silicon samples 800 clamped on each material loading jig 500 to be immersed in the etching solution are basically the same, thereby ensuring that the surface etching depths and surface morphologies of each single crystal silicon sample 800 are basically the same.

[0035] In this embodiment, as Figure 6 and Figure 8 shown, a third driving assembly 600 is arranged between the rotating disk 210 and the middle plate 420. The third driving assembly 600 is used to drive the rotating disk 210 to rotate slowly around its own axis. The third driving assembly 600 includes a motor 610, a long shaft 620, a central shaft 630 and a conical transmission disk 640. The motor 610 is arranged on the middle plate 420, and the output shaft of the motor 610 is coaxially and fixedly connected to the long shaft 620. A conical transmission surface 621 is formed at one end of the long shaft 620 away from the motor 610. The central shaft 630 is coaxially arranged at one end of the rotating disk 210 and rotates out from the side of the material loading box 200. The conical transmission disk 640 is in transmission cooperation with the conical transmission surface 621.

[0036] When it is necessary to rotate the rotating disk 210 about its own axis, the motor 610 is started. The output shaft of the motor 610 drives the long shaft 620 to rotate. The long shaft 620 drives the conical transmission disk 640 to rotate through its conical transmission surface 621. The conical transmission disk 640 drives the central shaft 630 to rotate. The central shaft 630 drives the rotating disk 210 to rotate, thereby realizing the rotation of the rotating disk 210 about its own axis. It can be understood that specifically, the transmission between the conical transmission disk 640 and the conical transmission surface 621 can be a friction surface transmission or a gear transmission. In other embodiments, specifically for driving the rotating disk 210 to rotate about its own axis, the third driving assembly 600 includes a motor 610, a first transmission gear, a second transmission gear, and a central shaft 630. The motor 610 is arranged on the second connecting plate 430, the axis of the motor 610 is horizontal, the first transmission gear is fixedly connected to the output shaft of the motor 610, the central shaft 630 is coaxially and fixedly connected to one end of the rotating disk 210, the second transmission gear is coaxially and fixedly connected to the central shaft 630, and the first transmission gear is in transmission connection with the second transmission gear. When it is necessary to drive the rotating disk 210 to rotate about its own axis, the motor 610 is started. The output shaft of the motor 610 drives the first transmission gear to rotate. The first transmission gear drives the second transmission gear to rotate through a transmission belt. The second transmission gear drives the central shaft 630 to rotate. The central shaft 630 drives the rotating disk 210 to rotate, thereby realizing the low-speed rotation of the rotating disk 210 about its own axis.

[0037] In this embodiment, as Figure 9 and Figure 10 shown, the material loading fixture 500 includes a connecting rod 510, an outer clamping plate 520, an inner clamping plate 530, and a right clamping block 540. One end of the connecting rod 510 is arranged on the side wall of the material loading box 200. The inner clamping plate 530 is fixedly connected to the end of the connecting rod 510 far from the material loading box 200. The outer clamping plate 520 is elastically slidably connected to the outside of the inner clamping plate 530. Specifically, in order to enable the outer clamping plate 520 to be elastically slidably connected to the outside of the inner clamping plate 530, a compression spring is sleeved on the outer periphery of the connecting rod 510. One end of the compression spring is connected to the inner clamping plate 530, and the other end of the compression spring is connected to the outer clamping plate 520. And the outer clamping plate 520 can move relative to the inner clamping plate 530 along the axis of the corresponding connecting rod 510. There are multiple right clamping blocks 540. The multiple right clamping blocks 540 are arranged at equal intervals along the axis of the corresponding connecting rod 510 on the upper surface and the lower surface inside the outer clamping plate 520. The upper surface and the lower surface inside the inner clamping plate 530 are provided with left clamping blocks 550 at equal intervals along the axis of the corresponding connecting rod 510. When the outer clamping plate 520 moves relative to the inner clamping plate 530 along the axis of the corresponding connecting rod 510, the left clamping blocks 550 and the right clamping blocks 540 move away from each other.

[0038] When clamping the single-crystal silicon sample 800, the operator pulls the outer clamping plate 520, causing the outer clamping plate 520 to move relative to the inner clamping plate 530 along the axis of the corresponding connecting rod 510. At this time, the left clamping block 550 and the right clamping block 540 move away from each other, and the distance between the left clamping block 550 and the right clamping block 540 becomes larger. At this time, the operator places the single-crystal silicon sample 800 into the gap between the left clamping block 550 and the right clamping block 540, and then releases the outer clamping plate 520. At this time, the outer clamping plate 520 moves in the reverse direction under the action of the spring force, so that the left clamping block 550 and the right clamping block 540 approach each other, thereby completing the clamping of the single-crystal silicon sample 800 by the left clamping block 550 and the right clamping block 540.

[0039] It should also be supplemented that, in order to enable the inner clamping plate 530 and the outer clamping plate 520 to move relative to each other only along the axis of the connecting rod 510, specifically, slots are provided on both sides of the outer clamping plate 520 in the width direction of the outer clamping plate 520. In addition, the inner clamping plate 530 is designed as two separable parts. During installation, the inner clamping plate 530 slides through the slots and the side surface of the inner clamping plate 530 is in sliding contact with the bottom of the slots, and then the two parts of the inner clamping plate 530 are fixedly connected together. In this way, the inner clamping plate 530 and the outer clamping plate 520 can only move relative to each other along the axis of the connecting rod 510.

[0040] In this embodiment, a fourth driving assembly 700 is provided between the connecting rod 510 and the material loading box 200. The fourth driving assembly 700 is used to drive the connecting rod 510 to rotate around its axis. The fourth driving assembly 700 includes a planetary gear 710 and an external gear ring 720. There are multiple planetary gears 710, and the multiple planetary gears 710 correspond to the multiple central shafts 630 one by one, and the planetary gear 710 is coaxially and fixedly connected to the central shaft 630. The external gear ring 720 is arranged on the inner side wall of the material loading box 200, and the external gear ring 720 meshes with the planetary gear 710.

[0041] During the etching operation, the rotating disk 210 rotates around its own axis, and the rotating disk 210 drives the multiple connecting rods 510 to rotate synchronously, that is, the connecting rods 510 revolve following the rotating disk 210. At the same time, under the cooperative action of the planetary gear 710 and the external gear ring 720, the connecting rod 510 also rotates around its own axis (i.e., rotates self). At this time, the connecting rod 510 drives the inner clamping plate 530 to rotate synchronously, the inner clamping plate 530 drives the outer clamping plate 520 to rotate synchronously, and the outer clamping plate 520 and the inner clamping plate 530 drive the single-crystal silicon sample 800 to rotate synchronously, so that the time for each part of the single-crystal silicon sample 800 to be immersed in the etching solution is kept basically the same, thereby ensuring the overall etching uniformity of the single-crystal silicon sample 800, so as to facilitate the precise control of the etching depth and surface morphology of the surface of the single-crystal silicon sample 800.

[0042] In this embodiment, a liquid replenishing port 121 is provided outside the outer groove 120. The liquid replenishing port 121 is connected to a two-way valve. One interface of the two-way valve is used to replenish the etching solution, and the other interface is used to completely drain the etching solution from the etching tank 100.

[0043] A single-crystal silicon sample etching process uses the above single-crystal silicon sample etching system and includes the following steps: Cutting: Cut the single-crystal silicon sample from the single-crystal silicon wafer. The length of the cut single-crystal silicon wafer is about 2 cm, and the width is about 0.5 cm.

[0044] Primary cleaning: Wrap the single-crystal silicon sample with a blue film and put it into an ultrasonic machine for the first cleaning. The ultrasonic cleaning time is controlled within 3 - 5 minutes, and the ultrasonic cleaning temperature is controlled within 20 - 50 °C. The purpose is to remove the particulate impurities on the surface of the single-crystal silicon sample.

[0045] Drying: Put the cleaned single-crystal silicon sample into a vacuum dryer to dry it.

[0046] Clamping: The operator pulls the outer clamping plate to clamp the dried single-crystal silicon sample between the right clamping block and the left clamping block.

[0047] Preheating: Before the loading box is immersed in the etching solution, the etching solution in the outer groove surrounds the loading box on all sides, and the etching solution in the inner groove is located at the bottom of the loading box, thereby forming a temperature wrap around the single-crystal silicon sample in the loading box for preheating it.

[0048] Etching: Before the loading box enters the etching solution in the inner groove and after the loading box enters the etching solution in the inner groove, make the connecting rod rotate around its own axis and revolve around the axis of the rotating disk at the same time. The immersion time lasts for about 1 minute, and the temperature of the etching solution is controlled within 20 - 30 °C. After the single-crystal silicon sample has been immersed in the etching solution for 1 minute, make the loading box move vertically upward so that the single-crystal silicon sample is removed from the etching solution. At the same time, drain the etching solution in the loading box through the liquid discharge port, then let the single-crystal silicon sample stand for 1 minute. At the same time, first drain the etching solution in the inner groove and the outer groove through the liquid replenishing port, and then replenish new etching solution into the inner groove and the outer groove. After the standing ends, make the loading box move vertically downward again so that the immersion time of the single-crystal silicon sample lasts for about 1 minute. After repeating the above operations about 10 times, the etching process ends.

[0049] Rinsing: Put the etched single-crystal silicon sample into a cleaning agent for rinsing. The rinsing temperature is controlled within 20 - 35 °C, and the rinsing time is controlled within 3 - 15 minutes.

[0050] Secondary cleaning: The ultrasonic cleaning time is controlled within 3 - 5 minutes, and the ultrasonic cleaning temperature is controlled within 20 - 50 °C.

[0051] Secondary drying: Blow hot air along the etched surface of the single-crystal silicon sample to dry the etched surface, and then put it into a vacuum dryer for drying after drying.

[0052] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0053] The above-described embodiments only represent several implementation manners of the present invention, and the description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A single-crystal silicon sample etching system, characterized in that, Comprising: An etching tank filled with an etching solution. The etching tank is divided into an inner tank and an outer tank, both the top of the inner tank and the outer tank are open. A liquid discharge port is provided in the upper part of the inner tank, and a communication hole is provided in the lower part of the inner tank. A material loading box capable of moving in the vertical direction, which is used to place a single crystal silicon sample. The material loading box is located inside the inner tank and the outer side wall of the material loading box is slidably sealed with the inner tank. A cover plate capable of moving in the vertical direction, and the cover plate is located inside the outer tank and is slidably sealed with the outer tank. During the etching operation, the material loading box moves vertically downward, so that the etching solution inside the inner tank flows directionally through the communication hole into the outer tank. When the material loading box moves vertically until its inside is connected to the communication hole, the material loading box stops moving downward. At this time, the cover plate moves vertically downward, so that the etching solution inside the outer tank flows directionally into the material loading box through the communication hole. At the same time, suction is applied through the liquid discharge port to make the etching solution flowing into the material loading box flow directionally from bottom to top.

2. The monocrystalline silicon sample etching system according to claim 1, characterized in that A first driving assembly is provided outside the etching tank, and the first driving assembly is used to drive the cover plate to move in the vertical direction. The first driving assembly includes a first linear driving element, a connecting frame and a first connecting plate. The first linear driving element is arranged outside the etching tank. The connecting frame is fixedly connected to the power end of the first linear driving element. The upper end of the first connecting plate is fixedly connected to the connecting frame, and the lower end of the first connecting plate is fixedly connected to the upper surface of the cover plate.

3. A single-crystal silicon sample etching system according to claim 2, characterized in that, A second driving assembly is also provided outside the etching tank, and the second driving assembly is used to drive the material loading box to move in the vertical direction. The second driving assembly includes a second linear driving element, an intermediate plate and a second connecting plate. The second linear driving element is arranged outside the etching tank. The intermediate plate is fixedly connected to the power end of the second linear driving element. The upper end of the second connecting plate is fixedly connected to the intermediate plate, and the lower end of the second connecting plate is fixedly connected to the outer side surface of the material loading box.

4. A monocrystalline silicon sample etching system according to claim 3, characterized in that, A rotating disk is rotatably arranged inside the material loading box. The axis of the rotating disk is horizontal, and a plurality of material loading clamps are equidistantly arranged in the circumferential direction of the rotating disk. The material loading clamps are used to clamp the single crystal silicon sample.

5. A monocrystalline silicon sample etching system according to claim 4, characterized in that, A third driving assembly is provided between the rotating disk and the intermediate plate, and the third driving assembly is used to drive the rotating disk to rotate slowly around its own axis.

6. The single-crystalline silicon sample etching system according to claim 5, characterized in that, The third driving assembly includes a motor, a long shaft, a central shaft and a conical transmission disk. The motor is arranged on the intermediate plate, and the output shaft of the motor is coaxially and fixedly connected to the long shaft. A conical transmission surface is provided at the end of the long shaft away from the motor. The central shaft is coaxially arranged at one end of the rotating disk and the central shaft rotates out from the side surface of the material loading box. The conical transmission disk is in transmission cooperation with the conical transmission surface.

7. A single-crystal silicon sample etching system according to claim 4, characterized in that, The material loading clamp includes a connecting rod, an outer clamping plate, an inner clamping plate and a right clamping block. One end of the connecting rod is arranged on the side wall of the material loading box. The inner clamping plate is fixedly connected to the end of the connecting rod away from the material loading box. The outer clamping plate is elastically and slidably connected to the outside of the inner clamping plate, and the outer clamping plate can move relative to the inner clamping plate along the axis of the corresponding connecting rod. There are a plurality of right clamping blocks, and the plurality of right clamping blocks are equidistantly arranged on the upper surface and the lower surface inside the outer clamping plate along the axis of the corresponding connecting rod. Left clamping blocks are equidistantly arranged on the upper surface and the lower surface inside the inner clamping plate along the axis of the corresponding connecting rod. When the outer clamping plate moves relative to the inner clamping plate along the axis of the corresponding connecting rod, the left clamping block and the right clamping block move away from each other.

8. A monocrystalline silicon sample etching system according to claim 7, characterized in that, A fourth driving assembly is provided between the connecting rod and the material loading box, and the fourth driving assembly is used to drive the connecting rod to rotate around its axis.

9. A single-crystal silicon sample etching system according to claim 8, wherein, The fourth driving assembly includes a planetary gear and an external gear ring. There are multiple planetary gears. The multiple planetary gears correspond to multiple central shafts one by one, and the planetary gears are coaxially and fixedly connected to the central shafts. The external gear ring is arranged on the inner side wall of the material loading box, and the external gear ring meshes with the planetary gears.

10. A single-crystalline silicon sample etching process, characterized in that, The single crystal silicon sample etching system according to any one of claims 1-9 is used.

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