Wet etching method and device

Abstract

The invention provides a wet etching method and device, and belongs to the technical field of semiconductor chip manufacturing. The wet etching method comprises the following steps: forming a metal layer on the surface of a wafer; the wafer is controlled to move back and forth between a first position and a second position until the corrosion operation of the metal layer is completed, when the wafer is located at the first position, the wafer intrudes into the corrosion solution of the corrosion groove, and when the wafer is located at the second position, the wafer is located outside the corrosion solution of the corrosion groove. The problem of inconsistent metal corrosion rates can be improved, and the pattern corrosion precision of the metal layer is improved.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor chip manufacturing technology, and in particular to a wet etching method and apparatus. Background Technology

[0002] In semiconductor device fabrication, tank etching is a common wet process. Tank etching involves immersing the wafer in a tank containing chemical reagents, selectively removing metal through chemical reactions to achieve fine pattern transfer and structural shaping. It is a key wet step in semiconductor metal interconnect processes.

[0003] In related technologies, tank etching typically involves immersing the wafer in a tank containing an etching solution, relying on static or simple agitation to achieve contact between the solution and the wafer.

[0004] However, as the reaction proceeds, the reactants in the tank are gradually consumed, while byproducts accumulate, causing uneven composition of the reagent in different locations within the tank, resulting in inconsistent corrosion rates. Furthermore, temperature differences in the reagent or gas generated by the chemical reaction cause changes in liquid density, leading to slight liquid flow. However, this flow is usually very weak and insufficient to ensure continuous and uniform contact of fresh reagent with all parts of the wafer. This can easily lead to a situation where reactants are not replenished in time after localized consumption, resulting in uneven metal corrosion rates and thus affecting pattern accuracy. Summary of the Invention

[0005] This disclosure provides a wet etching method and apparatus that can improve the problem of inconsistent metal corrosion rates and enhance the accuracy of patterned etching of metal layers. The technical solution is as follows: On one hand, this disclosure provides a wet etching method, which includes: forming a metal layer on the surface of a wafer; controlling the wafer to reciprocate between a first position and a second position until the etching of the metal layer is completed, wherein when the wafer is in the first position, the wafer is immersed in the etching solution of the etching tank, and when the wafer is in the second position, the wafer is outside the etching solution of the etching tank.

[0006] In one implementation of this disclosure, controlling the wafer to reciprocate between a first position and a second position includes controlling the frequency of the wafer's reciprocating movement between the first position and the second position to be greater than or equal to 20 Hz.

[0007] In another implementation of the present disclosure, when controlling the wafer to reciprocate between the first position and the second position, the method further includes: controlling the temperature of the etching solution in the etching tank to be 20°C to 30°C, and controlling the circulation flow rate of the etching solution injected into the etching tank to be 8L / Min to 12L / Min.

[0008] In another implementation of this disclosure, controlling the wafer to reciprocate between a first position and a second position includes: when the wafer moves to the first position, immersing the wafer in the etching tank to a depth greater than or equal to 10 cm; and when the wafer moves to the second position, ensuring that the distance between the wafer and the liquid surface of the etching tank is greater than or equal to 10 cm.

[0009] In another implementation of the present disclosure, the corrosion rate of the metal layer is greater than or equal to 1400 angstroms / min, and the uniformity of the corrosion rate of the metal layer is greater than or equal to 3.6%.

[0010] On the other hand, this disclosure provides a wet etching apparatus, which includes an etching tank, a carrier, and a drive unit. The etching tank contains an etching solution, and the carrier is used to mount a wafer. The drive unit controls the carrier to reciprocate between a first position and a second position until the etching operation is completed. When the carrier is in the first position, it is immersed in the etching solution in the etching tank. When the carrier is in the second position, it is located outside the etching solution in the etching tank.

[0011] In another implementation of the present disclosure, the drive unit is further configured to control the vehicle to reciprocate between the first position and the second position at a frequency greater than or equal to 20 Hz.

[0012] In another implementation of this disclosure, the wet etching apparatus further includes a temperature sensor, a heating element, and a controller. The controller is electrically connected to the temperature sensor and the heating element, respectively. The temperature sensor is used to detect the temperature of the solution in the etching tank. The controller is used to acquire the detected temperature of the temperature sensor in real time, and control the heating element to heat or stop heating the etching solution in the etching tank based on the detected temperature, so that the temperature of the etching solution in the etching tank is maintained at 20°C to 30°C.

[0013] In another implementation of the present disclosure, the wet corrosion apparatus further includes an electric pump, and the controller is electrically connected to the electric pump. The controller is used to control the electric pump to inject corrosion solution into the corrosion tank at a circulation flow rate of 8L / Min to 12L / Min.

[0014] In another implementation of this disclosure, the driving component includes a robotic arm. The robotic arm grasps the carrier and immerses it in the corrosion tank to a depth greater than or equal to 10 cm, thereby moving the carrier to the first position. The robotic arm also grasps the carrier at a distance greater than or equal to 10 cm from the liquid surface of the corrosion tank, thereby moving the carrier to the second position.

[0015] The beneficial effects of the technical solutions provided in this disclosure include at least the following: The wet etching method provided in this disclosure first forms a metal layer on the surface of a wafer, and then controls the wafer to move back and forth between a first position and a second position until the etching of the metal layer is completed. When the wafer is in the first position, it is immersed in the etching solution of the etching tank; when the wafer is in the second position, it is outside the etching solution of the etching tank.

[0016] By repeatedly lifting and immersing the wafer in the solution at a fixed oscillation frequency, this oscillation process effectively increases the flow rate of the solution on the wafer surface. The rapid solution flow quickly washes away byproducts on the wafer surface, such as metal ions or bubbles generated during the reaction. The presence of these byproducts can affect the etching reaction; timely removal helps ensure the normal progress of the etching reaction. Furthermore, the oscillation process increases forced convection of the solution. Forced convection allows for sufficient exchange of old and new solution at different locations on the wafer, avoiding inconsistent etching rates caused by uneven solution composition. Simultaneously, the oscillation process also increases the dissolved oxygen content in the solution. Sufficient oxygen can accelerate the metal oxidation reaction, thereby increasing the etching rate of the wafer metal. Therefore, the wet etching method provided in this disclosure not only improves the etching rate of the metal on the wafer but, more importantly, ensures the uniformity of etching, effectively improving pattern accuracy and making the semiconductor manufacturing process more stable and reliable. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of a wet corrosion method provided in an embodiment of this disclosure; Figure 2 This is a diagram showing the usage status of a wet etching apparatus provided in an embodiment of this disclosure; Figure 3 This is a diagram showing the usage status of a wet corrosion apparatus provided in an embodiment of this disclosure.

[0019] The markings in the diagram are explained as follows: 10. Etching tank; 20. Vehicles; 30. Drive components; 40. Controller; 41. Temperature sensor; 42. Heating element; 43. Electric pump; 50. Wafer. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0021] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” “third,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the elements or objects preceding “comprising” or “including” encompass the elements or objects listed following “comprising” or “including” and their equivalents, and do not exclude other elements or objects. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” “right,” “top,” and “bottom,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0022] Figure 1 This is a flowchart of a wet corrosion method provided in an embodiment of this disclosure. Figure 1 As shown, the wet etching method includes: Step S11: Form a metal layer on the surface of the wafer.

[0023] Step S12: Control the wafer to move back and forth between the first and second positions until the etching of the metal layer is completed.

[0024] When the wafer is in the first position, it is immersed in the etching solution of the etching tank; when the wafer is in the second position, it is outside the etching solution of the etching tank.

[0025] The wet etching method provided in this disclosure first forms a metal layer on the surface of a wafer, and then controls the wafer to move back and forth between a first position and a second position until the etching of the metal layer is completed. When the wafer is in the first position, it is immersed in the etching solution of the etching tank; when the wafer is in the second position, it is outside the etching solution of the etching tank.

[0026] By repeatedly lifting and immersing the wafer in the solution at a fixed oscillation frequency, this oscillation process effectively increases the flow rate of the solution on the wafer surface. The rapid solution flow quickly washes away byproducts on the wafer surface, such as metal ions or bubbles generated during the reaction. The presence of these byproducts can affect the etching reaction; timely removal helps ensure the normal progress of the etching reaction. Furthermore, the oscillation process increases forced convection of the solution. Forced convection allows for sufficient exchange of old and new solution at different locations on the wafer, avoiding inconsistent etching rates caused by uneven solution composition. Simultaneously, the oscillation process also increases the dissolved oxygen content in the solution. Sufficient oxygen can accelerate the metal oxidation reaction, thereby increasing the etching rate of the wafer metal. Therefore, the wet etching method provided in this disclosure not only improves the etching rate of the metal on the wafer but, more importantly, ensures the uniformity of etching, effectively improving pattern accuracy and making the semiconductor manufacturing process more stable and reliable.

[0027] Step S11 may include: growing a layer of Cu metal on the surface of a Si substrate using physical vapor deposition.

[0028] The substrate can be a Si substrate, a sapphire substrate, or a SiC substrate; the metal layer can be a Cu layer, an Ag layer, or an AlSiCu layer, and can be flexibly selected according to actual needs.

[0029] Before the etching operation in step S12, the process may also include: using photolithography, employing materials such as photoresist, and precisely creating the desired pattern through exposure, development, and other operations to form a mask on the surface of the metal layer. The mask allows for precise control of the contact between the etching solution and the metal layer, achieving high-precision patterned etching of the metal layer.

[0030] When controlling the reciprocating movement of the wafer in step S12, it may include controlling the frequency of the wafer's reciprocating movement at the first and second positions to be greater than or equal to 20 Hz.

[0031] High-frequency reciprocating motion greatly enhances forced convection of the solution. More than 20 reciprocations per second allow for faster and more frequent exchange of solution with the wafer surface, ensuring thorough mixing of old and new solutions across the wafer. This effectively avoids the problem of localized reactant depletion without timely replenishment, ensuring a consistent corrosion environment across the entire wafer surface and thus guaranteeing uniform corrosion rates.

[0032] Furthermore, the intense solution flow generated by the high-frequency movement has a strong scouring force, which can quickly and efficiently wash away byproducts such as metal ions and bubbles generated during the reaction on the wafer surface. The timely removal of these byproducts prevents them from hindering the corrosion reaction, allowing the corrosion reaction to proceed more smoothly, thereby increasing the overall corrosion rate.

[0033] Furthermore, high-frequency movement can also increase the dissolved oxygen content of the solution. Sufficient oxygen accelerates the metal oxidation reaction, further speeding up the metal corrosion process, while also helping to maintain the stability and efficiency of the corrosion reaction.

[0034] Optionally, during the process of controlling the reciprocating movement of the wafer, at the beginning of the corrosion reaction, when there is sufficient reactant, the oscillation frequency can be appropriately reduced to decrease excessive disturbance of the solution; at the end of the corrosion reaction, when the reactant is reduced, the oscillation frequency can be increased to accelerate the replenishment of fresh solution.

[0035] Among these methods, multiple experiments can be conducted in advance to record the time points from the onset of corrosion to the appearance of significant changes in the reaction rate under different conditions.

[0036] For example, after multiple tests, it was found that for a copper metal layer on a specific wafer, under given etching solution formulation and a temperature of 25°C, the reactants are sufficient for the first 2 to 3 minutes; this stage can be defined as the initial stage of the etching reaction. After 3 minutes, the reactants are gradually consumed, entering the final stage of the etching reaction. In actual production, a timer is started when etching begins, and the oscillation frequency is adjusted according to the set time. A lower oscillation frequency is used for the first 2 to 3 minutes, and the oscillation frequency is increased after 3 minutes.

[0037] Optionally, the corrosion effect can be further optimized by dynamically adjusting the oscillation frequency through real-time monitoring of corrosion rate and solution composition.

[0038] In the example selection, when the corrosion rate decreases to 1200 angstroms / minute, the frequency of reciprocating movement can be increased; when the corrosion rate reaches 1800 angstroms / minute, the frequency of reciprocating movement can be decreased.

[0039] When controlling the reciprocating movement of the wafer in step S12, it may also include: controlling the temperature of the etching solution in the etching tank to be 20°C to 30°C, and controlling the circulation flow rate of the etching solution injected into the etching tank to be 8L / Min to 12L / Min.

[0040] In the above implementation method, controlling the temperature of the etching solution within the range of 20℃ to 30℃ allows the chemical reaction to proceed at a relatively stable and suitable rate. If the temperature is too low, the reaction rate will slow down, leading to low etching efficiency and prolonged production time; while if the temperature is too high, the reaction may become too vigorous, making it difficult to precisely control the process and extent of etching, easily resulting in over-etching and affecting the accuracy and quality of the pattern. A suitable temperature ensures the stability and controllability of the etching reaction, allowing the etching process to proceed as expected.

[0041] Controlling the circulation flow rate between 8 L / min and 12 L / min provides sufficient flow to ensure a continuous and stable supply of fresh etching solution to the wafer surface, promptly replacing the solution after surface reaction. This ensures that all parts of the wafer are always in contact with a fresh solution of uniform composition. This helps improve the uniformity of solution composition and prevents situations where reactants are consumed in certain areas without timely replenishment. Simultaneously, a stable circulation flow rate also promotes solution flow, enhances convection, further washes away byproducts on the wafer surface, improves etching uniformity and rate, and ultimately enhances the quality and efficiency of the entire metal layer etching process.

[0042] Optionally, a local heating zone can be set up at the bottom of the etching tank, in the area directly opposite the wafer, so that the solution temperature near the wafer is slightly higher than that in other areas, thereby accelerating the metal oxidation reaction rate in that area. Combined with the uniform flow of the overall solution, this achieves more precise corrosion control and improves the corrosion uniformity of complex pattern areas.

[0043] Optionally, a stirring device can be added to the etching tank. This stirring device generates multi-directional solution flow. For example, it can create horizontal circulation. This multi-directional flow can more comprehensively scour all parts of the wafer, reducing dead zones and further improving the adequacy of solution exchange.

[0044] When controlling the reciprocating movement of the wafer in step S12, it may also include: when controlling the wafer to move to the first position, making the depth of the wafer immersed in the etching tank greater than or equal to 10cm.

[0045] By controlling the wafer immersion depth to ≥10cm, sufficient solution coverage and uniform contact can be ensured. An immersion depth of ≥10cm ensures that the entire wafer is completely submerged in the etching solution, avoiding the risk of uneven localized etching caused by shallow immersion, which would leave the wafer edges exposed to air or only in contact with a thin layer of solution. For large wafers (e.g., 300mm), sufficient immersion depth maximizes the contact area between the solution and the wafer surface, allowing the etching reaction to occur simultaneously across the entire wafer surface, further improving the overall consistency of pattern accuracy.

[0046] Meanwhile, the deeper immersion depth places the wafer in a stable hydrostatic environment, resulting in a more uniform pressure distribution on the wafer surface. This helps reduce abnormal solution flow caused by surface fluctuations or edge effects. This stable hydrostatic condition provides a more controllable environment for the corrosion reaction, avoiding localized fluctuations in the reaction rate caused by pressure differences, thus ensuring the uniformity of the corrosion rate of the metal layer.

[0047] Furthermore, with shallow immersion (e.g., <10cm), the solution near the wafer is more susceptible to evaporation due to ambient temperature, leading to increased local solution concentration or accumulation of byproducts. A depth of ≥10cm reduces the exposed surface area of ​​the solution, minimizing the interference of evaporation on the solution composition and maintaining the stability of the etching solution. Simultaneously, a deeper immersion layer buffers minor disturbances caused by wafer movement, preventing gradient differences in solution composition due to insufficient local mixing, and further ensuring that the solutions contacting different locations on the wafer have similar reactivity.

[0048] When controlling the reciprocating movement of the wafer in step S12, it may also include: when controlling the wafer to move to the second position, making the distance between the wafer and the liquid surface of the etching tank greater than or equal to 10cm.

[0049] By controlling the distance between the wafer and the liquid surface to be ≥10cm, it can be ensured that the wafer is completely removed from the etching tank, allowing the wafer to fully contact oxygen. The oxygen is used to accelerate the metal oxidation reaction, thereby increasing the corrosion rate of the wafer metal.

[0050] Furthermore, after the wafer leaves the solution, it needs sufficient space to allow the solution adhering to its surface to drip off or evaporate naturally, while simultaneously accelerating the removal of byproducts such as bubbles. At the same time, a larger air gap allows airflow to purge the wafer surface, helping residual solution evaporate quickly and prompting bubbles generated during the reaction (such as gases produced by metal oxidation) to break up and detach from the wafer surface more rapidly. This not only reduces byproduct residue on the wafer surface but also further improves the cleanliness of the wafer surface after etching, indirectly ensuring pattern accuracy and metal layer quality.

[0051] In this embodiment of the disclosure, the corrosion rate of the metal layer is greater than or equal to 1400 angstroms / min, and the uniformity of the corrosion rate of the metal layer is greater than or equal to 3.6%.

[0052] In related technologies, when the wafer is always immersed in the etching tank, the etching rate of the metal layer is 600 angstroms / min, and the uniformity of the etching rate of the metal layer is 13.4%.

[0053] This embodiment of the present disclosure optimizes the corrosion rate and uniformity of the metal layer by controlling the reciprocating movement of the wafer and controlling the reciprocating movement frequency to ≥20Hz, so that the immersion depth of the wafer is ≥10cm and the distance from the surface of the corrosion solution when entering and leaving the etching tank is ≥10cm. It also combines the solution temperature of 20℃ to 30℃ and the circulation flow rate of 8L / Min to 12L / Min.

[0054] Data comparison shows that the etching rate of this embodiment reaches 1400 Å / min, which is approximately 133% higher than that of related technologies (600 Å / min), significantly shortening the time for a single etching operation and improving production efficiency. Simultaneously, the etching rate uniformity is 3.6% (compared to 13.4% in related technologies), representing an improvement of over 73%. This indicates that the etching rate difference between different regions of the wafer is extremely small, effectively avoiding localized over-etching or under-etching problems and ensuring the dimensional accuracy and consistency of the metal pattern.

[0055] Figure 2 This is a diagram illustrating the operational status of a wet etching apparatus provided in this embodiment. Figure 3 This is a diagram showing the usage status of a wet corrosion apparatus provided in an embodiment of this disclosure. Figure 2 This illustration shows the state of wafer 50 within the etching tank. Figure 3 This illustration shows the state where wafer 50 is located outside the etching tank.

[0056] like Figure 2 , 3 As shown, the wet etching apparatus includes an etching tank 10, a carrier 20, and a drive unit 30. The etching tank 10 is filled with an etching solution, and the carrier 20 is used to mount the wafer 50.

[0057] The drive unit 30 controls the carrier 20 to reciprocate between a first position and a second position until the corrosion operation is completed. When the carrier 20 is in the first position, it is immersed in the corrosion solution of the corrosion tank 10; when the carrier 20 is in the second position, it is outside the corrosion solution of the corrosion tank 10.

[0058] The wet etching apparatus drive unit 30 provided in this embodiment creates a dynamic solution exchange environment by controlling the carrier 20 to reciprocate between a first position (immersed in solution) and a second position (detached from solution). When the carrier 20 is in the first position, the wafer 50 is completely immersed in the etching solution, comes into contact with fresh reactants, and undergoes an etching reaction. When the carrier 20 moves to the second position, the wafer 50 is detached from the solution, and byproducts attached to its surface (such as bubbles and metal ion deposits) are rapidly detached due to the loss of solution support. At the same time, the concentration of reactants in the solution is locally restored. This effectively alleviates the compositional gradient problem caused by the static solution in static etching, ensuring that all positions of the wafer 50 are always in contact with a relatively uniform fresh solution, thereby guaranteeing the consistency of the etching rate.

[0059] Furthermore, the reciprocating movement of the carrier 20 causes the wafer 50 to rapidly switch between inside and outside the solution, creating strong mechanical disturbances. When the wafer 50 is re-immersed from outside the solution, the fresh solution quickly coats the surface of the wafer 50 due to inertia; when it is detached from the solution, the surface solution is carried away by the movement of the wafer 50, creating a local negative pressure that attracts the surrounding fresh solution to replenish it. This high-frequency action is equivalent to applying forced convection to the solution, effectively increasing the contact frequency and mixing efficiency between the solution and the surface of the wafer 50. On the one hand, the fresh solution can quickly replenish reactants (such as oxidants) to maintain the continuous progress of the corrosion reaction; on the other hand, byproducts (such as metal ions or bubbles generated by the reaction) are promptly carried away from the surface of the wafer 50, preventing them from covering the metal layer and hindering the reaction.

[0060] Optionally, the drive unit 30 is also used to control the vehicle 20 to reciprocate at a frequency greater than or equal to 20 Hz at a first position and a second position.

[0061] High-frequency reciprocating motion greatly enhances the forced convection of the solution. More than 20 reciprocations per second allow for faster and more frequent exchange of solution with the wafer 50 surface, ensuring thorough mixing of old and new solutions at all locations on the wafer 50. This effectively avoids the problem of localized reactant depletion without timely replenishment, ensuring a consistent corrosion environment across the entire wafer 50 surface and thus guaranteeing uniform corrosion rates.

[0062] Furthermore, the intense solution flow generated by the high-frequency movement has a strong scouring force, which can quickly and efficiently wash away byproducts such as metal ions and bubbles generated on the surface of wafer 50. The timely removal of these byproducts prevents them from hindering the corrosion reaction, allowing the corrosion reaction to proceed more smoothly, thereby improving the overall corrosion rate.

[0063] Furthermore, high-frequency movement can also increase the dissolved oxygen content of the solution. Sufficient oxygen accelerates the metal oxidation reaction, further speeding up the metal corrosion process, while also helping to maintain the stability and efficiency of the corrosion reaction.

[0064] Optionally, such as Figure 2 , 3 As shown, the wet corrosion apparatus also includes a temperature sensor 41, a heating element 42, and a controller 40. The controller 40 is electrically connected to the temperature sensor 41 and the heating element 42, respectively. The temperature sensor 41 is used to detect the temperature of the solution in the corrosion tank 10.

[0065] The controller 40 is used to acquire the detected temperature of the temperature sensor 41 in real time, and control the heating element 42 to heat or stop heating the corrosion solution in the corrosion tank 10 based on the detected temperature, so that the temperature of the corrosion solution in the corrosion tank 10 is maintained at 20°C to 30°C.

[0066] In the above implementation, the temperature sensor 41 can monitor the solution temperature in real time, and the controller 40 dynamically controls the start and stop of the heating element 42 based on the detected value, ensuring that the solution temperature is stably maintained within the optimal range of 20℃ to 30℃. Within this range, the chemical reaction rate is moderate and stable, which avoids both the slow reaction caused by low temperature (low corrosion efficiency) and the runaway reaction caused by high temperature (excessive corrosion or pattern distortion), thereby ensuring the maximization and uniformity of the metal layer corrosion rate. The stable temperature environment can also reduce the local concentration differences of solution components caused by thermal fluctuations, avoid solution density changes and irregular flow caused by temperature differences, and further suppress local corrosion rate fluctuations.

[0067] For example, the temperature sensor 41 can be a resistance temperature detector (RTD), which has high accuracy and good stability and can accurately measure the temperature of the solution.

[0068] In the example selection, the heating element 42 can be an immersion ceramic heating rod, which is corrosion resistant and provides uniform heating, and can act directly on the solution.

[0069] For example, the controller 40 may be a programmable logic controller (PLC), which can acquire temperature data in real time according to a preset program, accurately control the start and stop of the heating element 42, and stably maintain the solution temperature at 20°C to 30°C.

[0070] Optionally, such as Figure 2 , 3 As shown, the wet corrosion apparatus also includes an electric pump 43, and a controller 40 is electrically connected to the electric pump 43. The controller 40 is used to control the electric pump 43 to inject corrosion solution into the corrosion tank 10 at a circulation flow rate of 8L / Min to 12L / Min.

[0071] Under the control of the controller 40, the electric pump 43 can stably maintain a circulation flow rate of 8L / min to 12L / min. Firstly, the stable circulation flow creates a forced convection environment, accelerating the contact and exchange between the fresh etching solution and the surface of the wafer 50, ensuring a continuous supply of reactants to all areas of the wafer 50 and preventing a decrease in the etching rate due to localized consumption. Secondly, the circulating flow effectively washes away byproducts adhering to the surface of the wafer 50, preventing their accumulation from affecting the etching reaction and improving surface reactivity. Finally, the constant flow control ensures the uniformity of the solution composition, avoiding localized concentration gradient differences caused by unstable injection rates. Through this precise flow control, the device can improve the etching rate while optimizing etching uniformity, thereby enhancing the accuracy and consistency of metal layer pattern processing.

[0072] For example, the electric pump 43 can be a magnetically driven circulation pump. The magnetically driven circulation pump uses magnetic coupling transmission, has no mechanical seal, effectively prevents leakage of corrosive solutions, and avoids corrosion damage to the motor. It has good corrosion resistance and can adapt to various corrosive solutions. It provides stable flow, accurately achieving circulation flow requirements from 8L / min to 12L / min, ensuring stable circulation of the solution within the wet corrosion apparatus.

[0073] Optionally, the drive unit 30 includes a robotic arm that grips the carrier 20 and immerses it in the corrosion tank 10 to a depth greater than or equal to 10 cm, thereby moving the carrier 20 to a first position.

[0074] The robotic arm grasps the carrier 20 at a distance of 10cm or more from the liquid surface of the corrosion tank 10, and moves the carrier 20 to the second position.

[0075] When the carrier 20 is immersed to a depth of ≥10cm by a robotic arm, the carrier 20 (including the wafer 50) can be completely submerged in the etching solution, ensuring that all areas of the wafer 50 are in full contact with the fresh solution, avoiding localized exposure or uneven solution coverage caused by shallow immersion. At the same time, the deeper immersion position reduces the disturbance of the solution surface, placing the wafer 50 in a more stable solution environment, which helps maintain the uniformity of the etching reaction and ensures that the reaction conditions are consistent throughout the metal layer.

[0076] Furthermore, when the carrier 20 is removed from the liquid surface, the distance between the carrier 20 and the liquid surface is ≥10cm, which ensures that the wafer on the carrier 20 is completely removed from the etching tank, allowing the wafer to fully contact with oxygen and using oxygen to accelerate the metal oxidation reaction, thereby increasing the corrosion rate of the wafer metal.

[0077] In this embodiment of the disclosure, the corrosion rate of the metal layer is greater than or equal to 1400 angstroms / min, and the uniformity of the corrosion rate of the metal layer is greater than or equal to 3.6%.

[0078] In the relevant technology, when the wafer 50 is always immersed in the etching tank 10, the etching rate of the metal layer is 600 angstroms / min, and the uniformity of the etching rate of the metal layer is 13.4%.

[0079] This embodiment of the present disclosure controls the reciprocating movement of the wafer 50 and controls the reciprocating movement frequency to be ≥20Hz, so that the immersion depth of the wafer 50 is ≥10cm and the distance from the surface of the etching solution when entering and leaving the etching tank 10 is ≥10cm. It also combines the solution temperature of 20°C to 30°C and the circulation flow rate of 8L / Min to 12L / Min to optimize the etching rate and uniformity of the metal layer.

[0080] Data comparison shows that the etching rate of this embodiment reaches 1400 Å / min, which is approximately 133% higher than that of related technologies (600 Å / min), significantly shortening the time for a single etching operation and improving production efficiency. Simultaneously, the etching rate uniformity is 3.6% (compared to 13.4% in related technologies), representing an improvement of over 73%. This indicates that the etching rate differences across different regions of the wafer are extremely small, effectively avoiding localized over-etching or under-etching issues and ensuring the dimensional accuracy and consistency of the metal pattern.

[0081] The above is not intended to limit this disclosure in any way. Although this disclosure has been disclosed above through embodiments, it is not intended to limit this disclosure. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this disclosure. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this disclosure without departing from the content of the technical solution of this disclosure shall still fall within the scope of the technical solution of this disclosure.

Claims

1. A wet etching method, characterized in that, The wet etching method includes: A metal layer is formed on the surface of the wafer; The wafer is controlled to move back and forth between a first position and a second position until the etching of the metal layer is completed. When the wafer is in the first position, it is immersed in the etching solution of the etching tank. When the wafer is in the second position, it is outside the etching solution of the etching tank.

2. The wet etching method according to claim 1, characterized in that, Controlling the wafer to reciprocate at the first and second positions includes: The frequency at which the wafer reciprocates between the first position and the second position is greater than or equal to 20 Hz.

3. The wet etching method according to claim 1, characterized in that, When controlling the wafer to reciprocate between the first and second positions, the method further includes: The temperature of the corrosion solution in the corrosion tank is controlled to be between 20°C and 30°C, and the circulation flow rate of the corrosion solution injected into the corrosion tank is controlled to be between 8L / min and 12L / min.

4. The wet etching method according to claim 1, characterized in that, Controlling the wafer to reciprocate at the first and second positions includes: When the wafer is moved to the first position, the depth of the wafer immersed in the etching tank is greater than or equal to 10 cm. When the wafer is moved to the second position, the distance between the wafer and the liquid surface of the etching tank is greater than or equal to 10 cm.

5. The wet etching method according to any one of claims 1 to 4, characterized in that, The corrosion rate of the metal layer is greater than or equal to 1400 angstroms / min, and the uniformity of the corrosion rate of the metal layer is greater than or equal to 3.6%.

6. A wet etching apparatus, characterized in that, The wet etching apparatus includes an etching tank (10), a carrier (20), and a drive unit (30). The etching tank (10) contains an etching solution, and the carrier (20) is used to mount a wafer (50). The drive unit (30) is used to control the carrier (20) to move back and forth between a first position and a second position until the corrosion operation is completed. When the carrier (20) is in the first position, the carrier (20) is immersed in the corrosion solution of the corrosion tank (10). When the carrier (20) is in the second position, the carrier (20) is outside the corrosion solution of the corrosion tank (10).

7. The wet etching apparatus according to claim 6, characterized in that, The drive unit (30) is also used to control the vehicle (20) to reciprocate between the first position and the second position at a frequency greater than or equal to 20 Hz.

8. The wet corrosion apparatus according to claim 6 or 7, characterized in that, The wet corrosion apparatus further includes a temperature sensor (41), a heating element (42), and a controller (40). The controller (40) is electrically connected to the temperature sensor (41) and the heating element (42) respectively. The temperature sensor (41) is used to detect the solution temperature in the corrosion tank (10). The controller (40) is used to acquire the detection temperature of the temperature sensor (41) in real time, and control the heating element (42) to heat or stop heating the corrosion solution in the corrosion tank (10) based on the detection temperature, so that the temperature of the corrosion solution in the corrosion tank (10) is maintained at 20°C to 30°C.

9. The wet etching apparatus according to claim 8, characterized in that, The wet corrosion apparatus also includes an electric pump (43), and the controller (40) is electrically connected to the electric pump (43). The controller (40) is used to control the electric pump (43) to inject corrosion solution into the corrosion tank (10) at a circulation flow rate of 8L / Min to 12L / Min.

10. The wet etching apparatus according to claim 8, characterized in that, The drive unit (30) includes a robotic arm, which grasps the carrier (20) and immerses it in the corrosion tank (10) to a depth greater than or equal to 10 cm, thereby moving the carrier (20) to the first position. The robotic arm grasps the carrier (20) at a distance of 10 cm or more from the liquid surface of the corrosion tank (10), thereby moving the carrier (20) to the second position.

Images