Wet etching equipment and wet etching method

Abstract

The present invention provides a wet etching device and a wet etching method. The wet etching device includes an etching chamber and an adsorption module. One end of the adsorption module is connected to the drainage port of the etching chamber and / or the adsorption module is arranged in the etching chamber. The etching chamber is used for wet etching of silicon oxide, silicon or silicon nitride on a substrate. The adsorption module is provided with an adsorption substance for adsorbing the etching product silicon compound. The etching liquid in the etching process of silicon oxide, silicon or silicon nitride material in the etching chamber flows through the adsorption module, and the etching product silicon compound is adsorbed and removed by the adsorption module, thereby realizing the regeneration of the etching liquid. The wet etching device of the present invention is provided with an adsorption module capable of adsorbing silicon compounds on the circulation path of the etching liquid, which can effectively extend the service life of the etching liquid, reduce the use cost and reduce the environmental pollution caused by the waste liquid discharge of the etching liquid, and can reduce the frequency of replacing the etching liquid, which is helpful to improve production efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor manufacturing, in particular to wet etching technology, and in particular to a wet etching device and a wet etching method. Background Art

[0002] Integrated circuits are the foundation of the information industry, and integrated circuit manufacturing is an important part of the integrated circuit industry. In semiconductor manufacturing, wet etching is a commonly used process for removing dielectric materials such as silicon, silicon oxide or silicon nitride compounds on substrates. The corrosion mechanism of silicon and / or its inorganic compound materials on the substrate in the etching solution is quite different, so the service life of the etching solution is affected by many factors. Among them, the increase in the concentration of etching products in the etching solution is one of the most important factors affecting the service life of the etching solution. How to remove etching products in the etching solution, extend the service life of the etching solution, reduce costs, save resources and improve production efficiency is an important topic. One of the etching products of silicon and / or its inorganic compound materials on the substrate in the etching solution is a silicon-containing compound, hereinafter referred to as a silicon compound. The present invention acts on the etching product silicon compound by an adsorbent substance, and the etching product silicon compound is adsorbed on the adsorbent substance to achieve the purpose of removing the etching product silicon compound, which can effectively extend the service life of the etching solution to reduce costs, and reduce the operation of replacing the etching solution to improve production efficiency.

[0003] Taking the wet etching of silicon nitride as an example, the wet etching of silicon nitride is usually carried out with an etching solution containing phosphoric acid, and the chemical reaction equation is as follows:

[0004] 3Si3N4+4H3PO4+36H2O=4(NH4)3PO4+9Si(OH)4,

[0005] Among them, phosphoric acid mainly plays a catalytic role, with a relatively small consumption, and the main substance component that reacts with silicon nitride is water. As the silicon nitride etching reaction proceeds, the content of silicon compound Si(OH)4, the etching product of silicon nitride in the phosphoric acid etching solution, increases. When the concentration of Si(OH)4 rises to a level exceeding a certain solubility, the silicon nitride etching reaction may gradually stop and silicon oxide particles may appear on the substrate, causing a significant adverse effect on the product yield.

[0006] Taking wet etching of silicon oxide film as an example, the commonly used etching solution is diluted hydrofluoric acid solution (DHF) or buffered oxide etchant (BOE), where the basic chemical reaction equation is as follows:

[0007] SiO2+6HF=H2SiF6+3H2O

[0008] Taking wet etching of silicon as an example, isotropic wet etching of silicon uses a mixed solution of nitric acid, hydrofluoric acid and water. The basic chemical equation is as follows:

[0009] Si+HNO3+6HF=H2SiF6+HNO2+H2O+H2↑

[0010] Anisotropic wet etching of silicon uses alkaline substances, such as KOH, where the basic chemical reaction equation is as follows:

[0011] Si+4H2O=Si(OH)4+2H2↑

[0012] The above-mentioned etching products all contain silicon compounds, which enter the etching solution as the etching reaction proceeds. As the etching process of silicon and / or its inorganic compound materials in the etching solution proceeds, the content of silicon compounds in the etching solution gradually increases. When it rises to a certain concentration, silicon compound precipitation may occur, affecting the etching effect.

[0013] There is no effective solution to the above problems. The only way is to partially or completely replace the etching solution with fresh one to reduce the concentration of silicon compounds in the etching solution before processing the next batch of substrates. This results in a short service life of the etching solution, large amount of usage, waste of resources, high cost and low production efficiency, and a large amount of waste liquid discharge causes environmental pollution.

[0014] Although the industry has been committed to removing etching products, namely silicon compounds, from etching solutions to maximize the service life of etching solutions, the existence of silicon compounds in etching solutions is complex, and the treatment method of heating the etching solution and adding liquid to react with it is inefficient and cannot effectively remove silicon compounds. The present invention uses an adsorption module for adsorption, and the efficiency is significantly improved. Summary of the invention

[0015] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a wet etching device and a wet etching method, which are used to solve the problem in the prior art that when performing a wet etching process of silicon and / or its inorganic compound materials on a substrate, it is difficult to effectively remove the etching products in the etching solution, namely, silicon compounds, by adding water, heating the liquid, etc., and the etching solution cannot be recycled and can only be replaced frequently, resulting in a short service life of the etching solution and a large amount of usage, resulting in increased production costs, low production efficiency, and environmental pollution.

[0016] To achieve the above-mentioned purpose and other related purposes, the present invention provides a wet etching device, which includes an etching chamber and an adsorption module, one end of the adsorption module is connected to the drainage port of the etching chamber and / or the adsorption module is arranged in the etching chamber; the etching chamber accommodates a substrate to be processed and an etching liquid, and the etching liquid contacts the substrate to etch the material on the substrate and produce an etching product silicon compound, wherein the material on the substrate includes any one of silicon, silicon oxide and silicon nitride; the adsorption module is provided with an adsorbent, the etching liquid in the etching chamber enters the adsorption module, and the etching product silicon compound is removed by the adsorbent in the adsorption module.

[0017] Optionally, the adsorbent includes any one or more of ion exchange resin, aluminum oxide, zirconium oxide, titanium oxide, silicon oxide and organosilicon compounds, or any one or more of the above adsorbents with surface groups modified, wherein group modification refers to modification using one or more of the surface groups of fluorine, sulfonic acid, carboxyl, cyclohexyl, trimethylaminopropyl, benzenesulfonic acid propyl, ethylenediamine-N-propyl and the above adsorbents.

[0018] Optionally, the adsorbent includes silicon, silicon carbide, silicic acid polymer, polymer containing hydroxyl group, polymer containing carboxyl group and any one or more fluorine-based modified materials of the above adsorbents.

[0019] Optionally, the adsorption module further comprises a filtering unit, and the filtering unit is used to prevent the adsorbent from flowing out of the adsorption module.

[0020] Optionally, the wet etching equipment further includes a monitoring module for detecting the concentration of the silicon compound.

[0021] Optionally, the wet etching equipment further includes an adsorbent regeneration module.

[0022] Optionally, the wet etching equipment further includes one or more of a circulation pipeline, a pump, a filter, a heater, a heat exchanger, a liquid replenishment module and an automatic control module.

[0023] The present invention also provides a wet etching method, comprising the following steps:

[0024] Step S1: exposing one or a combination of silicon, silicon oxide or silicon nitride materials on the substrate to an etching solution for an etching process to generate an etching product silicon compound;

[0025] Step S2: using an adsorbent to adsorb the silicon compound, and separating the adsorbent from the etching solution to achieve recycling of the etching solution.

[0026] Optionally, the etching solution includes one or more of a phosphoric acid solution, a hydrofluoric acid solution, a tetramethylammonium hydroxide solution, a potassium hydroxide solution, and a sodium hydroxide solution.

[0027] Optionally, the adsorbent includes any one or more of ion exchange resin, aluminum oxide, zirconium oxide, titanium oxide, silicon oxide and organosilicon compounds, or any one or more of the above adsorbents with surface groups modified, wherein group modification refers to modification using one or more of the surface groups including sulfonic acid group, carboxyl group, cyclohexyl group, trimethylaminopropyl group, benzenesulfonic acid propyl group, ethylenediamine-N-propyl group and the above adsorbents.

[0028] Optionally, the adsorbent includes silicon, silicon carbide, silicic acid polymer, polymer containing hydroxyl group, polymer containing carboxyl group and any one or more fluorine surface modified materials of the above adsorbents.

[0029] Optionally, the method of separating the adsorbent from the etching solution includes one or more of filtration, cooling and precipitation.

[0030] Optionally, the method includes adjusting the adsorption of the silicon compound on the surface of the adsorbent to adjust the concentration of the silicon compound in the etching solution, wherein the adjustment method includes one or a combination of adjusting the temperature of the etching solution, adjusting the concentration of the etching solution and adjusting the temperature of the adsorbent.

[0031] Optionally, step S2 further includes adding an adsorption accelerator, wherein the adsorption accelerator includes one or a combination of water, hydrofluoric acid, ammonium fluoride and ammonium bifluoride.

[0032] As described above, the wet etching equipment and wet etching method provided by the present invention have the following beneficial effects: the wet etching equipment and method provided by the present invention provide an adsorption module capable of adsorbing silicon compounds on the circulation path of the etching liquid, which can effectively reduce the concentration of the etching product silicon compounds in the etching liquid, extend the service life of the etching liquid, reduce the use cost and reduce the environmental pollution caused by the waste liquid discharge of the etching liquid, and can reduce the frequency of replacing the etching liquid, which helps to improve production efficiency. The wet etching method provided by the present invention helps to improve etching efficiency and reduce etching costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figures 1 to 3 Shown are exemplary structural schematic diagrams of the wet etching equipment provided by the present invention in different embodiments.

[0034] Figure 4 Shown is a schematic structural diagram of a single-chip etching chamber provided by the present invention.

[0035] Figure 5 The process flow chart of the wet etching method of the present invention is illustrated.

[0036] Component number description

[0037] 11 Circulation pipeline

[0038] 12 Adsorption module

[0039] 13 Pump

[0040] 14 Filters

[0041] 15 Heater

[0042] 16 Valves

[0043] 17 Fluid Replenishment Module

[0044] 20 Etching chamber DETAILED DESCRIPTION

[0045] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. For example, when describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional view showing the device structure will not be partially enlarged according to the general proportion, and the schematic diagram is only an example, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0046] For ease of description, spatially relative terms such as "under", "below", "below", "below", "above", "on", etc. may be used herein to describe the relationship of one element or feature shown in the drawings to other elements or features. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the drawings. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

[0047] In the context of the present application, a structure in which a first feature is described as being "above" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0048] It should be noted that the diagrams provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the diagrams only show the components related to the present invention rather than the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed arbitrarily, and the layout of the components may also be more complicated. In order to make the diagrams as concise as possible, not all structures are marked in the drawings.

[0049] The present invention provides a wet etching device, which comprises an etching chamber and an adsorption module, wherein one end of the adsorption module is connected to a liquid discharge port of the etching chamber and / or the adsorption module is arranged in the etching chamber; the etching chamber accommodates a substrate to be processed and an etching liquid, and the etching liquid contacts the substrate to etch a material on the substrate and generate an etching product silicon compound, wherein the material on the substrate comprises any one or a combination of silicon, silicon oxide and silicon nitride; the adsorption module is provided with an adsorbent, the etching liquid in the etching chamber enters the adsorption module, and the etching product silicon compound is removed by the adsorbent in the adsorption module.

[0050] It should be noted that the materials to be etched, silicon, silicon oxide and silicon nitride, may refer to silicon, silicon oxide and silicon nitride in a general sense, or may refer to the above materials doped with certain elements.

[0051] It should be noted that the etching product silicon compound is generally a compound that dissolves in the etching solution. If it is a silicon compound that is not soluble in the etching solution, for example, if the concentration of the silicon compound exceeds the solubility in the etching solution to form an insoluble substance, it can be removed by a filter, and the etching product in a dissolved form can be removed by an adsorption module. Therefore, the etching product in the present invention, both in the form of dissolving or not dissolving in the etching solution, can be removed by the adsorption module.

[0052] Next, this specification will focus on using silicon nitride etching equipment and methods as examples to illustrate the wet etching equipment of the present invention, but the types and applications of the wet etching equipment and methods are not limited thereto.

[0053] Specifically, Figure 1As shown, the present invention provides a wet etching device, which includes an etching chamber 20 and an adsorption module 12, one end of which is connected to the drainage port of the etching chamber 20. In this embodiment, the adsorption module 12 is located outside the etching chamber 20. In other examples, the adsorption module 12 may also be located inside the etching chamber 20, or part of the adsorption module 12 is located inside the etching chamber 20 and part of it is located outside the etching chamber 20. In this embodiment, the etching chamber 20 is used for wet etching of silicon nitride material on a substrate. The adsorption module 12, or silicon removal module, is provided with an adsorption substance for adsorbing silicon compounds, a product of silicon nitride etching. The silicon nitride etching liquid during or after etching flowing out of the etching chamber 20 flows through the adsorption module 12, and the silicon compounds, a product of etching of the silicon nitride material, are removed by the adsorption module 12.

[0054] Based on the fact that the wet etching equipment is a silicon nitride wet etching equipment, the etching chamber 20 is used to contain an etching solution containing phosphoric acid and a substrate containing silicon nitride to be etched, so as to etch the silicon nitride material. The etching chamber 20 includes an etching solution discharge port and an etching solution inlet port, and the adsorption module 12 is used to adsorb silicon oxide compounds, which are the etching products of silicon nitride, i.e., an adsorbent is used, including but not limited to a solid adsorbent, and the etching solution after silicon nitride etching flows through the adsorption module 12, where the etching solution refers to an etching solution containing phosphoric acid, and the silicon oxide compounds, which are the etching products of silicon nitride, are removed by the adsorption module 12. In a further example, the other end of the adsorption module 12 is connected to the inlet port of the etching chamber 20, so that the phosphoric acid solution from which the silicon oxides are removed by the adsorption module 12 is transported back to the etching chamber 20, which can realize online processing, and help to further simplify the equipment structure, improve production efficiency and reduce production costs.

[0055] In a further example, the wet etching equipment may also include several of the circulation pipeline 11, the pump 13, the filter 14, the heater 15, the liquid replenishment module 17 and the automatic control module. For example, all of the above structures may be set, or some of them may be set as needed, and no excessive restrictions are made here.

[0056] In this embodiment, one end of the circulation pipeline 11 is connected to the discharge port of the etching chamber 20, or the adsorption module 12 is connected to the discharge port of the etching chamber 20 via the circulation pipeline 11, and the other end can be connected to the liquid inlet of the etching chamber 20. The adsorption module 12, the pump 13, the filter 14 and the heater 15 are all arranged on the circulation pipeline 11 and are connected to the circulation pipeline 11. The pump 13 is used to provide power to promote the flow of the etching liquid, for example, to promote the flow of the etching liquid in the entire circulation pipeline 11, wherein more than one pump 13 can be arranged on the entire circulation pipeline 11, and multiple pumps 13 can be arranged at different positions, for example, the pump 13 can be arranged at the discharge port and the adsorption module 12, and can also be arranged between the adsorption module 12 and the filter 14; the heater 15 is arranged between the filter 14 and the liquid inlet of the etching chamber 20, and is used to heat the phosphoric acid etching solution finally delivered to the etching chamber 20. The water content and temperature of the phosphoric acid etching solution are adjusted to the water content and temperature required for the etching process through the liquid replenishment module 17 such as the water replenishment module and the heater 15, so that the water content and temperature of the phosphoric acid etching solution finally entering the etching chamber 20 are maintained within a certain range, the purpose is to make the treated etching solution can be directly used for the etching of silicon nitride. Of course, according to needs, the liquid replenishment module 17 can be omitted, and water can be directly replenished into the etching chamber 20. No excessive restrictions are made here.

[0057] The adsorption module 12 is provided with an adsorbent (also referred to as an adsorbent material or a silicon removal material) for adsorbing silicon compounds produced by silicon nitride etching. When the etching solution containing silicon compounds produced by silicon nitride etching flows through the adsorption module 12, the silicon compounds can be adsorbed on the adsorbent to reduce the concentration of silicon compounds in the phosphoric acid etching solution. The adsorbent may include a solid, liquid or gel-like adsorbent, wherein the adsorbent may include any one or more of ion exchange resins, aluminum oxide, zirconium oxide, titanium oxide, silicon oxide and organic silicon compounds, or any one or more of the above adsorbents with surface group modified, wherein group modification refers to modification using one or more of fluoro groups, sulfonic acid groups, carboxyl groups, cyclohexyl groups, trimethylaminopropyl groups, benzenesulfonic acid propyl groups, ethylenediamine-N-propyl groups and the surface groups of the above adsorbents.

[0058] As an example, the adsorbent may include silicon, silicon carbide, silicic acid polymer, a polymer containing a hydroxyl group, a polymer containing a carboxyl group, and a fluorine-based modified material of any one or more of the above adsorbents.

[0059] Specifically, the adsorbent may be solid or liquid at room temperature, such as 25°C. When the adsorbent adopts a solid adsorbent, the form of the solid adsorbent may be, for example, surface-modified, porous, crystalline, or other forms. When the adsorbent adopts a solid adsorbent, it may include various shapes, such as flakes. When the adsorbent adopts a solid adsorbent, the adsorbent material may be partially or completely wrapped with a non-adsorbent material. As an example, the adsorbent may be loaded into the adsorption module 12 in the following manner. First, the adsorbent is placed in the adsorption module 12, and filtering devices of different shapes are arranged in the adsorption module 12 to prevent the adsorbent from moving out of the adsorption module 12; second, the adsorbent is processed into an integrated filter structure of different shapes, and the integrated filter is placed in the adsorption module 12.

[0060] As an example, the adsorbent may be provided to the adsorption module by an adsorbent supply module, which is connected to the adsorption module and is not shown herein.

[0061] As an example, the working modes of the adsorption module 12 include continuous mode and batch mode, which are used for continuous and batch removal of etching product silicon compounds in the etching solution, respectively. Figure 1 and Figure 2 As shown, in this embodiment, a diagram showing that the adsorption module 12 can be suitable for batch work is illustrated, wherein when the adsorption module 12 is working, by adjusting the valve 16, such as a three-way valve, the pipe section A can be in a closed state. When the adsorption module 12 needs to be replaced, such as for cleaning, etc., the valve 16 can be used to make the pipe section A open and the pipe section B closed, so as to suspend the adsorption process of the adsorption module 12 and avoid stagnation of the entire etching equipment. When the adsorption module 12 can work, the valve 16 can be adjusted again to make the pipe section B open. The specific settings can be selected according to needs. Of course, the selected adsorption module 12 can also be a continuous working mode. At this time, please refer to Figure 3 To remove the pipe section A.

[0062] In order to prevent the adsorbent from flowing out of the adsorption module 12, a filtering unit (not shown) is preferably further provided in the adsorption module 20 to filter the adsorbent through the filtering unit to separate the adsorbent from the etching liquid, wherein the method of separating the adsorbent from the etching liquid may include filtering, cooling, precipitation and the like, and preferably the particle size of the adsorbent is greater than the filtering accuracy of the filtering unit to prevent the adsorbent from entering the circulation pipeline.

[0063] After the etching liquid discharged from the drain port of the etching chamber 20 has had the silicon compounds removed in the adsorption module 12, the phosphoric acid etching liquid after the preliminary treatment is transported to the filter 14 with the assistance of the pump 13 for further filtration treatment, and then replenished, such as water, by the replenishment module 17 and the heater 15 to adjust the water content of the phosphoric acid etching liquid, and heated to a preset process temperature, and finally transported back to the etching chamber. The replenishment module 17 can also directly replenish water into the etching chamber 20. Because the silicon compounds are removed, the workload of the filter on the etching equipment can be reduced, which helps to extend the service life of the filter.

[0064] In one example, the circulation pipeline 11 may be directly connected to the etching chamber 20 .

[0065] As an example, the etching chamber 20 may include a multi-wafer type etching chamber or a single-wafer type etching chamber.

[0066] Specifically, Figure 1 to Figure 3 In the embodiment, the etching chamber 20 is a multi-chip etching chamber, such as a tank type, so as to perform etching operations on multiple substrates at the same time. An outer tank for collecting the discharged etching liquid is set between the etching chamber 20 and the adsorption module 12. The etching chamber 20 can also include an inner tank and an outer tank at the same time. The inner tank is used for silicon nitride etching, for example, and the outer tank is used to collect the circulating overflow phosphoric acid etching liquid. The phosphoric acid etching liquid in use overflows from the inner tank, is collected by the outer tank, and is transported to the circulation pipeline 11, and then transported back to the inner tank after being processed. Of course, according to needs, the etching chamber 20 can also adopt a single-chip etching chamber, such as Figure 4 As shown, it is suitable for single-chip processing needs.

[0067] In this embodiment, the etching chamber 20 is a circulating overflow tank, the outer tank is located outside the inner tank, and the phosphoric acid etching liquid after etching silicon nitride overflowing from the inner tank is discharged into the outer tank, and then transported to the circulation pipeline 11, and the treated etching liquid enters the inner tank to etch the silicon nitride substrate. Of course, in other examples, the outer tank can also be set at the bottom of the inner tank, or the inner tank and the outer tank can also be placed in completely different places, which is not strictly limited.

[0068] As an example, the adsorption module 12 may be single or multiple. When there are multiple modules, the multiple adsorption modules 12 may be all connected in series or all connected in parallel. The adsorption modules 12 may also be partially connected in series and partially connected in parallel, and there is no strict restriction on this. The wet etching equipment may also be provided with the adsorbent regeneration module (not shown), and the regeneration module is connected to the adsorption module 12. For example, the regeneration module includes a flushing pipeline. When it is necessary to clean the adsorption module 12, the control valves at both ends of the adsorption module 12 are closed, and the flushing pipeline is started to clean the adsorption module 12. The waste liquid after cleaning is directly discharged. The regeneration module can be cleaned when needed, and the adsorption module 12 can also be activated and regenerated by introducing special liquids when needed.

[0069] In one example, if Figure 1 As shown, the wet etching equipment also includes a temperature regulating module (not shown) for regulating the temperature of the phosphoric acid etching solution. By adjusting the temperature, the adsorption effect of the adsorption module 12 can be adjusted. The temperature regulating module can be connected to the adsorption module 12, and / or arranged on the circulation pipeline 11 between the outer tank and the adsorption module 12 (that is, the temperature regulating module can be single or more than two). The temperature regulating module can be a heat exchanger, and the heat exchanger can be arranged on the circulation pipeline 11 between the discharge port of the etching chamber 20 and the adsorption module 12 to control the temperature of the phosphoric acid etching solution in the circulation pipeline 11. Of course, in other examples, the temperature regulating module can also directly act on the adsorption module 12, such as using the heating unit or cooling unit in the temperature control module to control the temperature of the adsorbent in the adsorption module 12.

[0070] In order to accurately control the component ratio of the treated phosphoric acid etching solution and improve the treatment effect, as an example, the wet etching equipment also includes a monitoring module, which is arranged on the circulation pipeline 11 or the adsorption module 12 to sample and analyze the phosphoric acid etching solution in the circulation pipeline 11. The monitoring module may include but is not limited to an inductively coupled plasma emission spectrometer and an infrared spectrum, which is used to detect the concentration of silicon compounds in the phosphoric acid etching solution. The monitoring module can be single or multiple, for example, at least two, one is arranged on the circulation pipeline 11 between the adsorption module 12 and the outer tank, and the other is arranged on the circulation pipeline 11 between the adsorption module 12 and the filter 14, so as to analyze the etching solution before and after adsorption by the adsorption module 12, such as phosphoric acid etching solution. Of course, in other examples, a sampling line can also be set up separately, and both ends of the sampling line are connected to the circulation line 11, and the diameter of the sampling line is much smaller than the diameter of the circulation line 11 (for example, less than one quarter of the diameter of the circulation line 11), and the monitoring module is arranged on the sampling line, and valves for sampling can also be arranged at the front and rear ends of the monitoring module. The advantages of setting up a sampling line are, first, to avoid affecting the flow of liquid in the circulation line 11 due to sampling, and second, a sampling line with a small flow rate is more convenient for sampling and analysis. The extracted etching liquid sample passes through the sample processing unit in the analysis module, such as mixing with a certain amount of ultrapure water for quantitative dilution, and enters the analysis instrument for detection.

[0071] As an example, the wet etching device may further include a flow control module (not shown), which may be disposed on the circulation pipeline 11 between the adsorption module 12 and the outer tank to monitor the liquid flow in the circulation pipeline 11 in real time. There may be multiple flow control modules, and another flow control module may be disposed on the circulation pipeline 11 between the heater 15 and the inner tank. The circulation pipeline 11 may further include a temperature detection module (not shown), which may be disposed on the circulation pipeline 11 between the adsorption module 12 and the outer tank (i.e., the drainage port of the etching chamber) to detect the temperature of the phosphoric acid etching solution in real time; or the temperature detection module and the flow control module may be integrated into the same module and disposed on the circulation pipeline 11 between the outer tank and the adsorption module 12.

[0072] The filter 14 may be a high-efficiency filter, and the number of the filter 14 may be single or multiple. When there are multiple filters 14, the multiple filters 14 may be connected in series, or in parallel, or partially in parallel and partially in series. It is preferred that the multiple filters 14 are connected in parallel to form at least two pipelines, so that when the filter 14 on one of the flow paths fails, another flow path can be activated in time to improve the stability of the wet etching equipment.

[0073] As an example, the wet etching device further includes an automatic control module, such as a controller, to realize automatic control of the wet etching device. The controller can be electrically connected to the aforementioned modules with detection functions such as a monitoring module and a heater to control the operation of each module according to the corresponding detection results.

[0074] In another example, if Figure 2 As shown, the wet etching equipment is a silicon oxide etching equipment, and the etching chamber 20 is used to contain silicon oxide etching solution and a silicon oxide-containing substrate to be etched for silicon oxide etching. The silicon oxide etching equipment also includes one or more of a circulation pipeline 11, a pump 13, a filter 14 and a monitoring module, preferably all of which include the aforementioned structures, one end of the circulation pipeline 11 is connected to the discharge port of the etching chamber 20, and the other end is connected to the liquid inlet of the etching chamber 20, and the adsorption module 12, the pump 13, the filter 14 and the monitoring module are connected to the circulation pipeline. More specifically, on the circulation pipeline between the liquid discharge port and the liquid inlet of the etching chamber 20, the pump 13, the adsorption module 12 and the filter 14 are sequentially arranged in the direction away from the liquid discharge port, and there are two monitoring modules, one is arranged on the circulation pipeline 11 between the pump 13 and the adsorption module 12, and the other is arranged on the circulation pipeline 11 between the adsorption module 12 and the filter 14, so that the concentration of silicon compounds in the etching liquid after silicon oxide etching discharged from the etching chamber 20 before and after passing through the adsorption module 12 can be detected. The functions of each module refer to the above introduction and are not repeated for the purpose of brevity. The silicon oxide etching equipment can also be provided with an automatic control module such as a controller, and the controller is connected to the aforementioned monitoring module and other modules with detection functions to control the operation of other modules according to the detection results of each module, thereby improving the automation level of the equipment.

[0075] In another example, if Figure 3As shown, the wet etching equipment is a silicon etching equipment, and the etching chamber 20 is used to contain silicon etching solution and a silicon substrate to be etched for silicon oxide etching. The silicon etching equipment also includes one or more of a circulation pipeline 11, a pump 13, a filter 14, a heating module 15 and a monitoring module, preferably all of which include the aforementioned structures, one end of the circulation pipeline is connected to the discharge port of the etching chamber 20, and the other end is connected to the liquid inlet of the etching chamber 20, and the adsorption module 12, the pump 13, the filter 14, the heater module 15 and the monitoring module are connected to the circulation pipeline. More specifically, on the circulation pipeline between the liquid discharge port and the liquid inlet of the etching chamber 20, the pump 13, the adsorption module 12, the filter 14 and the heater module 15 are sequentially arranged in the direction away from the liquid discharge port, and there are two monitoring modules, one is arranged on the circulation pipeline between the pump 13 and the silicon removal module 12, and the other is arranged on the circulation pipeline between the silicon removal module 12 and the filter 14, so that the concentration of silicon compounds in the etching liquid after silicon etching discharged from the etching chamber before and after passing through the adsorption module 12 can be detected. The functions of each module refer to the above introduction and will not be repeated for the purpose of simplicity. The silicon etching equipment can also be provided with a controller, which is connected to the aforementioned monitoring module and other modules with detection functions to control the operation of other modules according to the detection results of each module, thereby improving the automation level of the equipment.

[0076] like Figure 1 to Figure 3 The wet etching equipment can be a multi-wafer processing equipment, such as a tank type, that is, it can etch dozens of substrates at the same time. This etching equipment has the advantages of high etching efficiency. Traditional multi-wafer wet etching equipment needs to frequently replace new etching liquid, but the wet etching equipment provided by the present invention can effectively reduce the amount of etching liquid because it realizes efficient and rapid processing of etching liquid. Of course, the wet etching equipment can also be a single-wafer processing equipment, such as Figure 4 As shown, in this case, a stage for placing the substrate is usually provided in the etching chamber, and the treated etching liquid is sprayed into the etching chamber through a nozzle. The wet etching equipment of the present invention is applicable to both etching methods, and can effectively remove the etching product silicon compound in the etching liquid, which helps to improve the etching efficiency and yield, and through the recycling and regeneration of the etching liquid, it helps to reduce the etching cost and improve the equipment output rate.

[0077] The present invention also provides a wet etching method, which can be performed according to the wet etching equipment described in any of the above schemes, but is not limited thereto. For the introduction of the wet etching equipment, please refer to the above content, which will not be repeated for the purpose of brevity.

[0078] The wet etching method may include the steps of:

[0079] Step S1: exposing one or a combination of silicon, silicon oxide or silicon nitride materials on the substrate to an etching solution for an etching process to generate an etching product silicon compound;

[0080] Step S2: using an adsorbent to adsorb the silicon compound, and separating the adsorbent from the etching solution to achieve recycling of the etching solution.

[0081] Specifically, the process of the wet etching method can be found in Figure 5 , wherein the wet etching method can be any one or a combination of a silicon wet etching method, a silicon nitride wet etching method and a silicon oxide wet etching method.

[0082] It should be noted that after the silicon compound in the etching solution is adsorbed by the adsorbent, it is generally necessary to separate the adsorbent from the etching solution. If not separated, the adsorbent will contact the substrate being processed and affect the quality of the substrate surface, such as solid adsorbents. In special cases, it is not necessary to separate the adsorbent and the etching solution, such as when the adsorbent is a liquid adsorbent and forms a homogeneous system with the etching solution, it is not necessary to separate.

[0083] When the wet etching is performed, the etching solution may include one or more of a phosphoric acid solution, a hydrofluoric acid solution, a tetramethylammonium hydroxide solution, a potassium hydroxide solution, and a sodium hydroxide solution. The adsorbent may include any one or more of ion exchange resins, aluminum oxide, zirconium oxide, titanium oxide, silicon oxide, and organosilicon compounds, or any one or more of the above adsorbents with modified surface groups, wherein group modification refers to modification using one or more of sulfonic acid groups, carboxyl groups, cyclohexyl groups, trimethylaminopropyl groups, benzenesulfonic acid propyl groups, ethylenediamine-N-propyl groups, and the surface groups of the above adsorbents. For example, the adsorbent may include silicon, silicon carbide, silicate polymers, polymers containing hydroxyl groups, polymers containing carboxyl groups, and any one or more fluorine-based modified materials of the above adsorbents. The method for separating the adsorbent from the etching solution may include one or more of filtration, cooling, and precipitation.

[0084] Different materials to be etched produce different silicon compounds as etching products in different etching solutions. For example, the product produced by etching silicon nitride materials in phosphoric acid solution is silicon oxide compounds, the product produced by etching silicon oxide materials in hydrofluoric acid solution is fluorine silicon oxide compounds, the silicon material in acidic etching solution, such as a mixed solution of hydrofluoric acid and nitric acid, produces fluorine silicic acid compounds, and the silicon material in alkaline etching solution, such as sodium hydroxide solution, produces silicon oxide compounds. For different etching product silicon compounds, different groups on the surface of the adsorbent, such as hydroxyl, carboxyl, fluorine, cyclohexyl, etc., are used to form hydrogen bonds, van der Waals forces or chemical bonds with the etching product silicon compound groups in the etching solution, so as to adsorb the silicon compounds from the etching solution and retain them on the surface of the adsorbent material to remove the etching product silicon compounds in the etching solution. For example, the silicon oxide compounds produced by silicon nitride in phosphoric acid solution and the silicon oxide compounds produced by silicon in alkaline etching solution, the groups of the above silicon oxide compounds and the groups on the surface of the adsorbent, such as silanol and carboxyl, form silicon-oxygen-silicon or carbon-oxygen-silicon bonds, thereby adsorbing on the surface of the adsorbent.

[0085] The concentration of the silicon compound in the etching solution is adjusted by adjusting the adsorption of the silicon compound on the surface of the adsorbent. The adjustment method may include one or a combination of adjusting the temperature of the etching solution, adjusting the concentration of the etching solution and adjusting the temperature of the adsorbent.

[0086] Furthermore, when using an adsorbent to adsorb silicon compounds, an adsorption accelerator may be provided, such as one or a combination of water, hydrofluoric acid, ammonium fluoride and ammonium bifluoride, to accelerate the adsorption of silicon compounds on the surface of the adsorbent, thereby accelerating the removal of the silicon compounds and improving efficiency.

[0087] The wet etching method is carried out by using the aforementioned wet etching equipment. After the etching of a silicon-containing film, such as a silicon nitride film, is completed in the etching chamber, the used etching solution, or the etching solution during the etching of the silicon nitride material, such as the etching solution containing phosphoric acid, flows through the adsorption module, and the silicon compound contained in the silicon nitride wet etching product is removed by the adsorption module. In the case where a water replenishment module and a heater module are provided, the concentration and temperature can also be adjusted to achieve the treatment of the phosphoric acid etching solution and can be directly used for the etching of the silicon nitride film, which can not only improve the etching efficiency, but also effectively reduce the use of the phosphoric acid etching solution, reduce the frequency of changing the etching solution, and effectively reduce the etching cost.

[0088] In summary, the present invention provides a wet etching device and a wet etching method. The present invention provides a wet etching device, the wet etching device includes an etching chamber and an adsorption module. The wet etching device of the present invention is provided with an adsorption module capable of absorbing silicon compounds on the recovery path of the etching liquid, which can effectively extend the service life of the etching liquid, reduce the use cost and reduce the environmental pollution caused by the waste liquid discharge of the etching liquid, and can reduce the frequency of replacing the etching liquid, which helps to improve production efficiency. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0089] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A wet etching device, characterized in that: The etching equipment includes an etching chamber and an adsorption module, one end of the adsorption module is connected to the liquid discharge port of the etching chamber through a circulation pipeline; the other end is connected to the liquid inlet of the etching chamber; wherein the circulation pipeline includes a valve, a pipe section A and a pipe section B, the adsorption module is arranged in the pipe section B, and the valve is used to control the etching liquid to flow to the pipe section A or the pipe section B; the etching chamber accommodates the substrate to be processed and the etching liquid, and the etching liquid contacts the substrate to etch the material on the substrate and generate an etching product silicon compound, wherein the material on the substrate includes silicon, silicon oxide and silicon nitride; the adsorption module is provided with an adsorbent, the etching liquid in the etching chamber enters the adsorption module, and the etching product silicon compound is removed by the adsorbent in the adsorption module; wherein the adsorbent is a solid chemical adsorbent, loaded in the adsorption module, including any one or more of ion exchange resin, aluminum oxide, zirconium oxide, titanium oxide, silicon oxide and organic silicon compound after surface group modification, wherein group modification refers to modification using one or more of sulfonic acid group, carboxyl group, cyclohexyl group, trimethylaminopropyl group, benzenesulfonic acid propyl group and ethylenediamine-N-propyl group.

2. The wet etching equipment according to claim 1, characterized in that: The adsorbent includes silicon, silicic acid polymer, silicon carbide, a polymer containing a hydroxyl group, a polymer containing a carboxyl group, and any one or more fluorine-based modified materials of the above adsorbents.

3. The wet etching equipment according to claim 1, characterized in that: The adsorption module further includes a filtering unit, and the filtering unit prevents the adsorbent from flowing out of the adsorption module.

4. The wet etching equipment according to claim 1, characterized in that: The wet etching equipment also includes a monitoring module for detecting the concentration of the silicon compound.

5. The wet etching equipment according to claim 1, characterized in that: The wet etching equipment also includes a regeneration module for the adsorbent.

6. The wet etching device according to any one of claims 1 to 5, characterized in that: The wet etching equipment also includes one or more of a pump, a filter, a heater, a heat exchanger, a liquid replenishment module and an automatic control module.

7. A wet etching method using the wet etching device according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step S1: exposing one or a combination of silicon, silicon oxide or silicon nitride materials on the substrate to an etching solution for an etching process to generate an etching product silicon compound; Step S2: using an adsorbent to adsorb the silicon compound, and separating the adsorbent from the etching solution to achieve recycling of the etching solution.

8. The wet etching method according to claim 7, characterized in that: The etching solution includes one or more of a phosphoric acid solution, a hydrofluoric acid solution, a tetramethylammonium hydroxide solution, a potassium hydroxide solution, and a sodium hydroxide solution.

9. The wet etching method according to claim 7, characterized in that: The adsorbent includes silicon, silicon carbide, silicic acid polymer, polymer containing hydroxyl group, polymer containing carboxyl group and any one or more fluorine-based modified materials of the above adsorbents.

10. The wet etching method according to claim 7, characterized in that: The method of separating the adsorbent from the etching solution includes one or more of filtration, cooling and precipitation.

11. The wet etching method according to claim 7, characterized in that: The concentration of the silicon compound in the etching solution is adjusted by adjusting the adsorption of the silicon compound on the surface of the adsorbent, wherein the adjustment method includes one or a combination of adjusting the temperature of the etching solution, adjusting the concentration of the etching solution and adjusting the temperature of the adsorbent.

12. The wet etching method according to claim 7, characterized in that: Step S2 also includes adding an adsorption accelerator, wherein the adsorption accelerator includes one or a combination of water, hydrofluoric acid, ammonium fluoride and ammonium bifluoride.

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