Method, device and computer-readable storage medium for controlling drug solution concentration

Abstract

The present application discloses a method, device and computer-readable storage medium for controlling the concentration of a liquid medicine, and belongs to the field of semiconductor process technology. A method for controlling the concentration of a liquid medicine, applied to semiconductor process equipment, the control method comprising: obtaining the mass difference of a silicon wafer before and after a preset time of reaction with a liquid medicine in a semiconductor process equipment; obtaining a first loss amount of active ingredients in the liquid medicine and the concentration of a silicification product according to the mass difference; judging whether the concentration of the silicification product is greater than or equal to a threshold; if not, adjusting the concentration of the active ingredient in the liquid medicine according to the first loss amount; if so, discharging part of the liquid medicine in the semiconductor process equipment according to the first discharge amount, and adjusting the concentration of the active ingredient in the liquid medicine according to the first discharge amount and the first loss amount. The present application can solve the problem of unstable processing caused by the fact that the active ingredients of the liquid medicine in the tank during the current silicon wafer processing process are continuously consumed as the reaction proceeds.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor process technology, and specifically relates to a method and device for controlling the concentration of a drug solution, and a computer-readable storage medium. Background Art

[0002] In semiconductor manufacturing processes or semiconductor processes, various reactive liquids are required, such as acid, alkali, organic solution and other liquids. Especially for semiconductor wet processes, these reactive liquids are often required to treat silicon wafers for different purposes. For example, in the field of solar photovoltaic power generation, the manufacturing process of solar cells involves the cleaning and texturing of silicon wafers. A certain concentration of reactive liquid is set in the texturing tank, cleaning tank and other liquid tanks of the texturing / cleaning equipment, which is used to etch and clean the silicon wafer for different purposes, such as etching the surface of the silicon wafer to form a velvet surface or etching (corrosion) to remove the surface layer of the silicon wafer. The quality of silicon wafer etching or cleaning has a certain impact on the performance of the device. Therefore, in order to maintain the stability of the etching or cleaning process and reduce or avoid the impact on the performance of the device, it is necessary to accurately control the concentration of the liquid in the equipment.

[0003] During the processing of silicon wafers, such as texturing or cleaning, the effective components (active ingredients) of the reactive liquid in the tank will be continuously consumed as the reaction proceeds, which will cause instability in the texturing or cleaning process. At present, in order to alleviate this phenomenon, the usual practice is to add liquid to the tank at intervals based on production experience to roughly maintain the concentration of the liquid, but this method is not effective and affects the texturing or cleaning effect. Summary of the invention

[0004] In view of the above problems, the present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the present invention provides a method for controlling the concentration of a chemical solution, a semiconductor process device and a computer-readable storage medium, which are mainly used to alleviate the problem of unstable processing caused by the active ingredients of the reactive chemical solution in the tank being continuously consumed as the reaction proceeds during the current silicon wafer processing process.

[0005] In order to solve the above technical problems, this application is implemented as follows:

[0006] The present application provides a method for controlling the concentration of a chemical solution, which is applied to semiconductor process equipment. The control method includes:

[0007] Obtaining the quality difference of silicon wafers before and after a preset time of reaction with a chemical solution in a semiconductor process equipment;

[0008] According to the mass difference, obtaining a first loss amount of the active ingredient in the drug solution and a concentration of the silicification product;

[0009] determining whether the concentration of the silicidation product is greater than or equal to a threshold;

[0010] If the concentration of the siliconized product is less than the threshold, adjusting the concentration of the active ingredient in the liquid medicine according to the first loss amount;

[0011] If the concentration of the silicidation product is greater than or equal to a threshold, part of the chemical solution in the semiconductor process equipment is discharged according to a first discharge amount, and the concentration of the active ingredient in the chemical solution is adjusted according to the first discharge amount and the first loss amount.

[0012] In addition, the method for controlling the concentration of the drug solution according to the present application may also have the following additional technical features:

[0013] In some embodiments, the step of adjusting the concentration of the active ingredient in the liquid medicine according to the first loss amount includes: obtaining a first replenishing liquid having a first volume and a first concentration of the active ingredient, wherein the first volume is less than or equal to the volume difference of the liquid medicine in the semiconductor process equipment corresponding to the mass difference, and the product of the first concentration and the first volume is the first loss amount;

[0014] The first replenishing liquid is added into the semiconductor process equipment.

[0015] In some embodiments, the step of adjusting the concentration of the active ingredient in the liquid medicine according to the first discharge amount and the first loss amount includes:

[0016] Obtaining a second loss amount of the active ingredient caused by discharging the first discharge amount of the liquid medicine;

[0017] Obtaining a second replenishing solution having a second volume and an active ingredient concentration of a second concentration, wherein the second volume is less than or equal to the volume difference of the drug solution in the semiconductor process equipment corresponding to the mass difference, and the product of the second concentration and the second volume is the sum of the first loss amount and the second loss amount;

[0018] The second replenishing liquid is added into the semiconductor process equipment.

[0019] In some embodiments, the step of obtaining a second loss amount of the active ingredient caused by discharging the first discharge amount of the liquid medicine comprises:

[0020] Obtaining a current concentration of the active ingredient in the drug solution after the silicon wafer reaction according to the initial volume of the drug solution before the silicon wafer reaction and the initial concentration of the active ingredient therein, and the current volume of the drug solution after the silicon wafer reaction;

[0021] The product of the first emission amount and the current concentration is taken as the second loss amount.

[0022] In some embodiments, the step of obtaining the current concentration of the active ingredient in the medicine solution after the silicon wafer reaction according to the initial volume of the medicine solution before the silicon wafer reaction and the initial concentration of the active ingredient therein, and the current volume of the medicine solution after the silicon wafer reaction, comprises:

[0023] Obtaining a current amount of the active ingredient in the drug solution after the silicon wafer reacts, wherein the current amount is a difference between a product of the initial volume and the initial concentration and the first loss amount;

[0024] The ratio of the current amount to the current volume is taken as the current concentration.

[0025] In some embodiments, the step of obtaining a first loss amount of the active ingredient in the drug solution and a concentration of the silicification product according to the mass difference comprises:

[0026] The first loss amount and the concentration of the silicidation product are obtained according to the proportional relationship in the chemical equation of the reaction between the silicon wafer and the active component.

[0027] In some embodiments, the drug solution includes the active ingredient and a solvent, and the active ingredient includes hydroxide ions.

[0028] An embodiment of the present application also provides a semiconductor process equipment, which is used to clean or etch silicon wafers using a chemical solution. The semiconductor process equipment includes a processor and a memory, a mass acquisition component, and a concentration adjustment component respectively coupled to the processor, wherein program instructions are stored on the memory, and the processor is capable of executing the program instructions and cooperating with the mass acquisition component and the concentration adjustment component to implement the method for controlling the concentration of the chemical solution as described above.

[0029] In some of the embodiments, the semiconductor process equipment includes a tank wet cleaning equipment or a tank wet texturing equipment.

[0030] The embodiment of the present application also provides a computer-readable storage medium, on which program instructions are stored. The program instructions can be executed by a processor to implement the method for controlling the concentration of the drug solution as described above.

[0031] Implementing the technical solution of the present invention has at least the following beneficial effects:

[0032] In the embodiment of the present application, the provided method for controlling the concentration of the liquid medicine can be applied to semiconductor process equipment. The method obtains the first loss amount of the active ingredient in the liquid medicine and the concentration of the silicification product according to the mass difference before and after the preset time of the reaction between the silicon wafer and the liquid medicine, and compares the relationship between the concentration of the silicification product and the threshold value. According to whether the concentration of the silicification product is less than the threshold value, or greater than or equal to the threshold value, appropriate operations such as replenishing or draining the liquid are performed, so that the concentration of the active ingredient in the liquid medicine can be accurately adjusted during the silicon wafer processing process, and the effective ingredient in the liquid medicine can be in a balanced state. Therefore, by adopting the control method of the present invention, without adding additional devices, the concentration of the liquid medicine and the concentration of the product can be controlled within a predetermined range, the stability of the silicon wafer processing such as cleaning or texturing can be maintained, and the processing of the silicon wafer can be made more stable, which helps to improve the yield of the device.

[0033] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of a method for controlling the concentration of a chemical solution in a semiconductor process provided for some exemplary embodiments of the present application;

[0035] Figure 2 A partial schematic diagram of a method for controlling the concentration of a chemical solution in a semiconductor process provided by some exemplary embodiments of the present application;

[0036] Figure 3 A partial schematic diagram of a method for controlling the concentration of a chemical solution in a semiconductor process provided for some exemplary embodiments of the present application. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0038] In the related art, in order to control the concentration of the liquid during cleaning or texturing, the liquid replenishment operation is usually performed at intervals based on production experience to roughly maintain the concentration of the liquid. However, the inventors of the present invention have found in their research that this treatment method based on experience is not effective and cannot accurately maintain the liquid within the required range, which affects the texturing or cleaning effect.

[0039] To solve the above technical problems, as one aspect of the present invention, in some embodiments, a method for controlling the concentration of a chemical solution is provided, which is applied to semiconductor process equipment, and the semiconductor process equipment can be used to clean or etch silicon wafers with a chemical solution.

[0040] It should be noted that the control method of this embodiment can be applied in the field of processing and manufacturing of semiconductor devices, such as in the field of solar cell manufacturing or in the field of integrated circuit silicon wafer manufacturing. For solar cell manufacturing, the cleaning, texturing or etching of silicon wafers requires the use of liquid medicine to treat the silicon wafers, so as to etch the surface of the silicon wafer to form a velvet surface or etch the surface layer of the silicon wafer. For the field of integrated circuit silicon wafer manufacturing, it involves the corrosion or cleaning process of silicon wafers, which uses the method of chemically corroding the surface of the silicon wafer to remove the damage caused to the silicon wafer during the production process, such as acid liquid or alkaline liquid at a certain concentration and a certain temperature reacting chemically with the silicon wafer, so as to achieve the purpose of uniform chemical thinning of the surface of the silicon wafer. For the sake of simplicity, the following mainly takes the texturing treatment of silicon wafers in the production and manufacturing of solar cells as an example to explain the control method of the present invention in detail. However, it should be understood that the control of the concentration of liquid medicine in the cleaning or chemical corrosion of silicon wafers has the same or similar principles, which will not be repeated here.

[0041] Optionally, the semiconductor process equipment includes, but is not limited to, a tank wet cleaning equipment or a tank wet texturing equipment. The following mainly uses the semiconductor process equipment as a tank wet texturing equipment as an example for explanation. The tank wet texturing equipment can adopt a conventional tank wet texturing equipment or a tank wet texturing equipment with an improved structure in the related technology. The tank wet texturing equipment includes a texturing tank, and an etching solution and a silicon wafer perform an etching reaction in the texturing tank to form a pyramid velvet structure on the surface of the silicon wafer. However, it can be understood that the control method of the embodiment of the present invention has the same or similar principles when applied to other related or similar semiconductor process equipment.

[0042] like Figure 1 As shown, the control method includes:

[0043] Step S1, obtaining the mass difference of a silicon wafer before and after a preset time of reaction with a chemical solution in a semiconductor process equipment.

[0044] In some embodiments, in step S1, obtaining the mass difference of the silicon wafer before and after the silicon wafer reacts with the chemical solution in the semiconductor process equipment for a preset time specifically includes:

[0045] Step 1: first weigh the mass of the silicon wafer, and then place the silicon wafer in a texturing tank of a semiconductor process equipment containing a chemical solution;

[0046] Step 2: The silicon wafer reacts with the drug solution for a preset time;

[0047] Step three, after reaching the preset time, the mass of the silicon wafer is weighed again to obtain the mass difference before and after the preset time of the silicon wafer reacting with the chemical solution in the semiconductor process equipment.

[0048] It should be noted that, in the process of texturing silicon wafers, the production efficiency is improved by continuously texturing multiple batches of silicon wafers. The above silicon wafers can be a batch of silicon wafers, that is, a batch of silicon wafers are placed in the texturing tank; the quality difference of the silicon wafers obtained can be the quality difference of a batch of silicon wafers. Each batch of silicon wafers can contain dozens or hundreds of silicon wafers. After the texturing of a batch of silicon wafers is completed in the texturing tank, the texturing treatment of the next batch of silicon wafers is continued.

[0049] Optionally, before placing a batch of silicon wafers into the texturing tank, the mass of the batch of silicon wafers can be weighed first (such as m1); after a period of etching time, that is, after reaching the preset time, the batch of silicon wafers can be taken out and the mass of the batch of silicon wafers can be weighed again (such as m2), and the difference between m1-m2 can be calculated to obtain the mass difference of the batch of silicon wafers after the preset time of reaction with the solution, that is, the reaction amount of Si in the batch of silicon wafers can be obtained.

[0050] In this embodiment, there may be many specific ways to obtain the quality difference of silicon wafers. For example, the quality of the silicon wafers may be weighed before being placed in the texturing tank, and the quality of the silicon wafers may be weighed again during the processing or after the texturing is completed; or, a quality monitoring component may be provided in the texturing tank, and the quality of the silicon wafers in the texturing tank may be tested by the quality monitoring component.

[0051] In this embodiment, the method for obtaining the mass difference of the silicon wafer is to weigh the mass of the silicon wafer before placing the silicon wafer in the semiconductor process equipment, and record it as the first mass; after reaching the preset etching time, the silicon wafer is taken out of the semiconductor process equipment, and the mass of the silicon wafer is weighed again, and recorded as the second mass, and the difference between the second mass and the first mass is calculated.

[0052] Optionally, a robotic arm is used to place the silicon wafer in a texturing tank of a semiconductor process equipment, and / or a robotic arm is used to take the silicon wafer out of the texturing tank of a semiconductor process equipment. For example, a robotic arm is used to transport the silicon wafer into the texturing tank, and after a preset etching time is reached, the robotic arm is used to take the silicon wafer out of the texturing tank.

[0053] It should be noted that the above-mentioned preset etching time can be set by those skilled in the art according to actual process conditions or relevant experience, and this embodiment does not limit this.

[0054] In some other embodiments, a quality monitoring component is provided in the semiconductor process equipment, and the quality monitoring component is used to detect the quality of the silicon wafer; the quality difference of the silicon wafer can also be obtained by using the quality monitoring component. Optionally, the quality monitoring component can include a quality sensor, and the quality sensor can be connected to the controller signal of the semiconductor process equipment.

[0055] The specific structure and working principle of the quality sensor or the controller in the semiconductor process equipment can refer to the prior art, which is not limited in this embodiment and will not be described in detail. The semiconductor process equipment can monitor the quality of silicon wafers during etching or cleaning processes.

[0056] Therefore, based on the above settings, taking the texturing process of silicon wafer as an example, a certain amount of liquid is added to the texturing tank, such as adding an alkaline etching solution of a first concentration, the mass of the silicon wafer is weighed, and the silicon wafer is transported to the texturing tank by a robotic arm. The hydroxide ions (OH - ) The surface of the silicon wafer is selectively etched to form a pyramid velvet structure on the surface of the silicon wafer. After the predetermined etching time is reached, the silicon wafer is taken away by a robotic arm, and the texturing effect is monitored by the quality difference of the silicon wafer before and after texturing. Taking the etching solution as NaOH solution and water as an example, the chemical reaction equation involved in the texturing process is as follows:

[0057] Si+2NaOH+H2O=Na2SiO3+2H2 (1)

[0058] During the texturing process, as the reaction proceeds, the concentration of the solution such as the alkaline etching solution continues to decrease, and the concentration of the silicide product such as sodium silicate continues to increase, which will affect the etching rate and thus the texturing effect. Therefore, it is necessary to control the alkali concentration and product concentration in the etching solution.

[0059] Step S2, obtaining a first loss amount of the active ingredient in the drug solution and a concentration of the silicification product according to the mass difference.

[0060] In some embodiments, the medical solution comprises an active ingredient and a solvent, and the active ingredient comprises hydroxide ions.

[0061] Optionally, the chemical solution, such as the etching chemical solution, may include an alkaline solution and water, wherein the alkaline solution is a mixture of an alkaline substance and water. The active component is an alkaline solution, the solvent is water, and the active component includes hydroxide ions (OH) for reacting with silicon (Si). - ). Of course, in other embodiments, other types of solvents or active ingredients may also be used.

[0062] Optionally, the alkaline substance includes, but is not limited to, sodium hydroxide (NaOH) or potassium hydroxide (KOH), that is, the alkaline solution can be a sodium hydroxide solution or a potassium hydroxide solution. Of course, other alkaline solutions that can react with the silicon wafer can also be used, and this embodiment is not limited to this.

[0063] The mass fraction of the alkaline substance in the alkaline solution can be 1%-65%, further can be 10%-50%, further can be 30%-40%, etc. For example, a 30%-40% sodium hydroxide alkaline solution can be used. The specific mass fraction of the alkaline substance such as sodium hydroxide or potassium hydroxide can be adjusted according to actual conditions, and this embodiment does not limit this.

[0064] The ratio of alkaline solution to water in the above-mentioned etching solution can be determined according to the equation for the reaction between the etching solution and silicon (Si) in the silicon wafer. Optionally, optional additives can be added to the etching solution, and the additives may not participate in the reaction; the additives in the etching solution may be added or not, and the specific type or amount of the additives can also be selected and set according to actual needs, which is not limited in this embodiment.

[0065] In addition, in other embodiments, the etching solution may also include an acidic solution, such as one of hydrofluoric acid and nitric acid, or a mixture of the two. For example, a solar cell texturing process combining acid texturing and alkali texturing may be used, such as acid texturing first and then alkali texturing. Acid texturing can clean the surface of the silicon wafer, and acid texturing can also corrode the surface of the silicon wafer.

[0066] Specifically, in some embodiments, the first loss amount and the concentration of the silicidation product may be obtained in the following manner:

[0067] The first loss amount and the concentration of the silicidation product are obtained according to the proportional relationship in the chemical equation of the reaction between the silicon wafer and the active component.

[0068] In this embodiment, the first loss amount of the active ingredient in the liquid medicine can be obtained according to relevant conversions, such as according to the above chemical reaction equation (1), when the reaction amount of Si is known, the first loss amount of the active ingredient in the liquid medicine can be calculated. The first loss amount can be, for example, the molar loss amount of the active ingredient in the liquid medicine, the mass loss amount of the active ingredient in the etching liquid medicine, or the concentration loss amount of the active ingredient in the etching liquid medicine, or the volume loss amount of the active ingredient in the etching liquid medicine, etc.

[0069] Step S3, determining whether the concentration of the silicidation product is greater than or equal to a threshold value.

[0070] Further, after the first loss amount of active ingredients in the liquid medicine and the concentration of the silicified product are known, it is necessary to judge the concentration of the silicified product, that is, to judge whether the concentration of the silicified product is greater than or equal to the threshold value. If the judgment is no, that is, the concentration of the silicified product is less than the threshold value, the following step S4 is performed. If the judgment is yes, that is, the concentration of the silicified product is greater than or equal to the threshold value, the following step S5 is performed.

[0071] In this embodiment, the quality difference of the silicon wafers is obtained; based on the quality difference of the silicon wafers, the first loss amount of active components in the etching solution and the concentration of the silicidation product are calculated; and the relationship between the concentration thresholds of the silicidation product is determined, so as to control the alkali concentration and product concentration in the etching solution.

[0072] In detail, according to the above reaction equation (1), the reaction amount of Si can be known according to the mass difference of the silicon wafer, so the mass of the consumed alkali and water and the generated silicification product sodium silicate can be calculated, and the total volume of the liquid in the texturing tank remains unchanged for a period of time, so the concentration of the silicification product sodium silicate can be calculated, so that the concentration of the silicification product sodium silicate can be compared with the preset product concentration threshold. It should be noted that the concentration threshold of the silicification product can be set according to relevant experience, and this embodiment does not limit the specific value of the threshold.

[0073] Step S4, adjusting the concentration of the active ingredient in the drug solution according to the first loss amount.

[0074] According to this embodiment, if the calculated concentration of the current silicide product (e.g., sodium silicate) is less than the threshold value, it means that the influence of the concentration of the silicide product on the etching rate is within an acceptable range, and drainage is not required, so that the concentration of the active ingredient in the etching solution can be directly adjusted according to the calculated first loss amount of the active ingredient in the etching solution. For example, the amount of replenishment is known according to the first loss amount, and then the corresponding amount of etching solution is added to the texturing tank. It should be understood that replenishment to the texturing tank is usually replenishment of alkaline solution and water of a certain concentration, that is, what is replenished is the substance that participates in the reaction and is continuously reduced with the texturing process. According to the first loss amount of the active ingredient in the etching solution and the amount of liquid that can be replenished in the texturing tank, the amount of replenishment of alkaline solution and pure water of appropriate concentration are selected, and added to the texturing tank, the alkali concentration is controlled within a predetermined range, and the volume of the etching solution is controlled within a predetermined value.

[0075] Step S5, discharging part of the chemical solution in the semiconductor process equipment according to the first discharge amount, and adjusting the concentration of the active ingredient in the chemical solution according to the first discharge amount and the first loss amount.

[0076] According to this embodiment, if the calculated concentration of the current silicide product (e.g., sodium silicate) is greater than or equal to the threshold, it means that the influence of the concentration of the silicide product on the etching rate is unacceptable, and the concentration of the silicide product in the mixed solution in the texturing tank needs to be controlled. At this time, the texturing tank needs to be drained. For example, the drainage operation can be performed first according to a preset fixed displacement, i.e., the first discharge volume, to discharge the mixed solution with a high concentration of silicide products in the texturing tank. Then, the concentration of the active ingredient in the liquid is adjusted according to the first discharge volume and the first loss volume, for example, a replenishment operation of a suitable concentration is selected.

[0077] Therefore, compared with the existing method of controlling the concentration of the liquid medicine according to the experience of the operator, the liquid medicine concentration control method provided in this embodiment provides a more scientific and reasonable calculation or operation control method, which obtains the first loss amount of the active ingredient in the liquid medicine and the concentration of the silicification product according to the mass difference before and after the preset time of the reaction between the silicon wafer and the liquid medicine, and compares the relationship between the concentration of the silicification product and the threshold value, and performs appropriate operations such as replenishing or draining the liquid according to the concentration of the silicification product being less than the threshold value, or being greater than or equal to the threshold value. Therefore, the method can control the concentration of the liquid medicine and the concentration of the product within a predetermined range without adding additional devices, can maintain the stability of the wet processing of the silicon wafer, solves the problem of unstable wet process execution caused by excessive or insufficient liquid medicine concentration, effectively improves the performance of the wet processing process, ensures the cleaning or texturing effect, and thus can improve the yield of the device. In addition, the method of the present invention can be used to supplement the content of the active ingredient in the liquid medicine multiple times in the wet processing process carried out in multiple cycles, improves the utilization rate of the active ingredient in the liquid medicine, and prolongs the service life of the liquid medicine.

[0078] In some embodiments, Figure 2 As shown, in the above step S4, if the concentration of the silicification product is less than the threshold value, the concentration of the active ingredient in the liquid medicine is adjusted according to the first loss amount, specifically including:

[0079] Step S11, obtaining a first replenishing solution with a first volume and an active ingredient concentration of a first concentration.

[0080] The first volume is less than or equal to the volume difference of the chemical solution in the semiconductor process equipment corresponding to the mass difference, and the product of the first concentration and the first volume is the first loss amount.

[0081] Step S12, adding the first replenishing liquid into the semiconductor process equipment.

[0082] The above-mentioned first concentration can be a molar concentration, and the first loss amount can be a molar loss amount of the active ingredient in the liquid medicine, so that it is easy to obtain relevant parameters and more convenient to calculate. According to this embodiment, if the calculated current concentration of the silicide product is less than the threshold value, it means that the influence of the concentration of the silicide product on the etching rate is within an acceptable range, and it is not necessary to drain the liquid, so that the first replenishing liquid whose product of the first concentration and the first volume is the first loss amount can be directly selected and then added to the semiconductor process equipment, such as adding it to the texturing tank of the semiconductor process equipment, so as to control the alkali concentration within a predetermined range and the volume of the etching liquid within a predetermined value.

[0083] like Figure 3 As shown, in some embodiments, in step S5, if the concentration of the silicidation product is greater than or equal to the threshold value, part of the liquid medicine in the semiconductor process equipment is discharged according to the first discharge amount, and the concentration of the active ingredient in the liquid medicine is adjusted according to the first discharge amount and the first loss amount, specifically including:

[0084] Step S21, obtaining a second loss amount of active ingredient caused by discharging the first discharge amount of liquid medicine.

[0085] Step S22, obtaining a second replenishing solution with a second volume and an active ingredient concentration of a second concentration, wherein the second volume is less than or equal to the volume difference of the drug solution in the semiconductor process equipment corresponding to the mass difference, and the product of the second concentration and the second volume is the sum of the first loss amount and the second loss amount.

[0086] Step S23, adding the second replenishing liquid into the semiconductor process equipment, for example, adding the second replenishing liquid into the texturing tank of the semiconductor process equipment.

[0087] According to this embodiment, if the calculated current concentration of the silicidation product is greater than or equal to the threshold value, it means that the influence of the silicidation product concentration on the etching rate is unacceptable, and it is necessary to drain the liquid first and obtain the second loss amount of the active component caused by the drainage, and then select the second replenishing liquid whose product of the second concentration and the second volume is the sum of the first loss amount and the second loss amount, and then add it to the semiconductor process equipment, such as adding it to the texturing tank of the semiconductor process equipment, so as to control the alkali concentration within a predetermined range and the volume of the etching solution within a predetermined value.

[0088] Optionally, the second loss amount of active ingredient caused by discharging the first discharge amount of liquid medicine can be obtained by the following steps:

[0089] Step S31, obtaining the current concentration of the active ingredient in the drug solution after the silicon wafer reaction according to the initial volume of the drug solution before the silicon wafer reaction and the initial concentration of the active ingredient therein, and the current volume of the drug solution after the silicon wafer reaction.

[0090] Specifically, the current amount of active ingredients in the drug solution after the silicon wafer reaction can be obtained first, and then the ratio of the current amount to the current volume is used as the current concentration, where the current amount is the difference between the product of the initial volume and the initial concentration and the first loss amount.

[0091] Step S32: taking the product of the first emission amount and the current concentration as the second loss amount.

[0092] Usually, the initial volume and initial concentration of the solution before texturing are known, that is, the total amount of active ingredients before texturing can be calculated, and the current remaining amount can be calculated based on the first loss amount and the total amount of active ingredients in the etching solution calculated previously, so that the current concentration can be calculated. At the same time, the drainage operation will also cause the loss of active ingredients. The second loss amount of the etching solution can be calculated based on the current concentration of the active ingredients in the solution and the first discharge amount. The second loss amount is the product of the first discharge amount and the current concentration. Therefore, based on the above, the total loss of active ingredients is known, that is, the replenishment amount of the second replenishing liquid is known, so that the appropriate concentration of replenishment, replenishment amount and pure water can be selected according to the total loss and the amount of replenishable liquid in the texturing tank, and added to the texturing tank to control the alkali concentration within a predetermined range and the volume of the solution within a predetermined value.

[0093] It should be noted that when the robot arm is used to take out the silicon wafer, a small amount of etching solution may be taken away. The logic similar to the above can also be used to appropriately replenish the active ingredient loss caused by the part of the solution taken away by the robot arm; for example, the amount of etching solution taken away by the robot arm each time the silicon wafer is taken out can be equivalent to the first fixed displacement mentioned above. However, since the amount of etching required by the robot arm when taking out the silicon wafer is usually small, it can sometimes be ignored, and this effect does not need to be considered every time the solution is replenished, or this factor can be considered at a replenishment after processing multiple batches of silicon wafers.

[0094] Optionally, the semiconductor process equipment includes a liquid supplement component and a first liquid storage tank for storing etching liquid, and the method for replenishing the etching liquid into the texturing tank of the semiconductor process equipment can be: control the liquid supplement component to extract part of the etching liquid from the first liquid storage tank and transport it to the texturing tank of the semiconductor process equipment. The amount of the part of the etching liquid extracted from the first liquid storage tank is the amount of liquid replenishment that needs to be added to the texturing tank calculated before, such as the first replenishing liquid or the second replenishing liquid.

[0095] In some embodiments, the semiconductor process equipment further includes a solution discharge member and a second liquid storage tank for storing the discharged mixed solution, and discharging at least part of the mixed solution in the semiconductor process equipment includes: controlling the solution discharge member to inject a first discharge amount of the mixed solution into the second liquid storage tank. That is, the first discharge amount of the mixed solution discharged from the texturing tank can be input into the second liquid storage tank for storage.

[0096] According to this embodiment, the semiconductor process equipment may include a texturing tank, a liquid supplement, a first liquid storage tank, a solution discharge member, and a second liquid storage tank, wherein one end of the texturing tank may be connected to the first liquid storage tank via the liquid supplement, and the other end of the texturing tank may be connected to the second liquid storage tank via the solution discharge member. In this way, it is convenient to perform liquid replenishment or liquid discharge operations, and it is easy to control, and the amount of liquid replenishment or liquid discharge can be controlled more accurately.

[0097] Optionally, the liquid medicine supplement includes one or more of a control valve, a flow meter, and a metering pump. For example, the liquid medicine supplement may be a control valve and a flow meter, which may be connected to a controller signal in a semiconductor process equipment; or the liquid medicine supplement may be a metering pump, which may be connected to a controller signal in a semiconductor process equipment.

[0098] Optionally, the solution discharge component includes one or more of a control valve, a flow meter, and a metering pump. For example, the solution discharge component may be a control valve and a flow meter, which may be connected to a controller signal in a semiconductor process equipment; or the solution discharge component may be a metering pump, which may be connected to a controller signal in a semiconductor process equipment.

[0099] It should be noted that the specific structure or connection setting and working principle of the above-mentioned control valve, flow meter and metering pump can refer to the existing technology, which is not limited in this embodiment and will not be described in detail here.

[0100] Based on the same inventive concept, an embodiment of the present application also provides a semiconductor process equipment, which is used to clean or etch silicon wafers using a chemical solution, and the semiconductor process equipment can implement the control method as described above.

[0101] The semiconductor process equipment includes a processor and a memory, a mass acquisition component and a concentration adjustment component respectively coupled to the processor, wherein the memory stores program instructions, and the processor can execute the program instructions and cooperate with the mass acquisition component and the concentration adjustment component to implement the aforementioned method for controlling the concentration of the drug solution.

[0102] Optionally, the semiconductor process equipment includes a tank wet cleaning equipment or a tank wet texturing equipment.

[0103] It should be understood that the semiconductor process equipment of this embodiment and the aforementioned method for controlling the concentration of the chemical solution are based on the same inventive concept, and thus have at least all the features and advantages of the method for controlling the concentration of the chemical solution, which will not be described in detail herein.

[0104] Based on the same inventive concept, an embodiment of the present application further provides a computer-readable storage medium, on which program instructions are stored. The program instructions can be executed by a processor to implement the aforementioned method for controlling the concentration of the drug solution.

[0105] The following further describes the method for controlling the concentration of the drug solution of the present application with specific examples. Those skilled in the art will understand that the description in the present invention is only a partial example, and any other suitable specific examples are within the scope of the present invention.

[0106] Example 1

[0107] A method for controlling the concentration of chemical solution in a semiconductor process is used in a silicon wafer texturing process, wherein a sodium hydroxide solution and water (ultrapure water) are used to texturing the silicon wafer. The control method comprises:

[0108] S1, obtaining the mass difference of the silicon wafer before and after the silicon wafer reacts with the chemical solution in the semiconductor process equipment for a preset time.

[0109] Specifically, the mass of the silicon wafer is first weighed, and then the silicon wafer is transported by a robotic arm to a texturing tank of a semiconductor process equipment containing a chemical solution (including a sodium hydroxide solution and water); the silicon wafer reacts with the chemical solution for a preset time, so that the chemical solution reacts with silicon to generate a silicidation product; after the preset time is reached, the mass of the silicon wafer is weighed again, thereby obtaining the mass difference between the silicon wafer before and after the preset time of reaction with the chemical solution in the semiconductor process equipment.

[0110] The chemical reaction equation involved in the texturing process is as follows:

[0111] Si+2NaOH+H2O=Na2SiO3+2H2

[0112] In the texturing tank, the initial concentration and initial volume of the liquid are known; this embodiment is described by taking the volume of the liquid in the texturing tank as 260 L, of which 226 L is ultrapure water and 34 L is 40% NaOH solution.

[0113] Among them, the mass difference of silicon wafers is obtained; for example, in the texturing process of silicon wafers, 400 silicon wafers are fed in each batch, and each silicon wafer is required to lose 0.8g in weight; or according to the weighing of the silicon wafers before and after the reaction, the mass difference of the batch of silicon wafers is 0.8×400=320g.

[0114] S2, obtaining a first loss amount of the active ingredient in the drug solution and a concentration of the silicification product according to the mass difference.

[0115] Specifically include:

[0116] The first loss amount and the concentration of the silicidation product are obtained according to the proportional relationship in the chemical equation of the reaction between the silicon wafer and the active component.

[0117] In order to facilitate the acquisition of relevant parameters or calculations, relevant conversions are performed. Chemical reactions follow the principle of electron conservation. According to the molar mass of silicon being 28 g / mol, it can be seen that the mass difference of 400 pieces of silicon converted into molar mass is: (0.8×400)÷28=11.43 mol.

[0118] Therefore, according to the quality difference of the batch of silicon wafers, the first loss amount of active ingredients in the solution and the concentration of the silicide product can be calculated. Specifically, according to the above chemical reaction equation, the molar amounts of NaOH and H2O consumed to corrode 11.43 mol of Si are: the molar amount of NaOH is 22.86 mol (11.43×2=22.86 mol), and the molar amount of H2O is 11.43 mol, thereby obtaining the first loss amount of the etching solution. The molar amount of the silicide product Na2SiO3 is 11.43 mol.

[0119] According to relevant literature such as the Chemical Handbook, the molar concentration of 40% NaOH solution is 14.3 mol / L; the molar mass of Na2SiO3 is 122.06 g / mol. Therefore, when the silicon wafer is textured, the volume of 40% NaOH solution required for etching reaction of each batch of silicon wafers is 22.86 mol÷14.3 mol / L=1.6 L, the volume of water required is 11.43×18=205 g=0.205 L, and the mass of the silicification product Na2SiO3 generated by the reaction is 11.43×122.06=1395 g, from which the concentration of Na2SiO3 can be calculated (such as 1395 g÷260 L=5.37 g / L).

[0120] Based on the above, the first loss amount of active ingredients in the liquid medicine and the concentration of the silicide product can be known. In addition, H2 will be generated during the etching reaction of the silicon wafer, and the generated H2 will be exhausted with ventilation without affecting the subsequent reaction.

[0121] S3, determining whether the concentration of the silicidation product is greater than or equal to a threshold.

[0122] If the judgment is no, that is, the concentration of the silicide product is less than the threshold, then the following step S4 is performed. If the judgment is yes, that is, the concentration of the silicide product is greater than or equal to the threshold, then the following step S5 is performed.

[0123] S4, adjusting the concentration of the active ingredient in the drug solution according to the first loss amount.

[0124] Specifically include:

[0125] Step 1, obtaining a first replenishing solution with a first volume and an active ingredient concentration of a first concentration, wherein the first volume is less than or equal to the volume difference of the drug solution in the semiconductor process equipment corresponding to the mass difference, and the product of the first concentration and the first volume is the first loss amount;

[0126] Step 2: Add the first replenishing liquid into the semiconductor process equipment, such as into the texturing tank of the semiconductor process equipment.

[0127] Exemplarily, the concentration threshold of the silicidation product is 20 g / L, and the concentration of the silicidation product Na2SiO3 calculated in step S2 is 5.37 g / L, which is less than the threshold value. The influence of the silicidation product Na2SiO3 on the progress of the etching reaction is within an acceptable range, and the etching solution can be replenished into the texturing tank according to the first loss amount of the active ingredient in the etching solution, that is, the first replenishing liquid is added to the texturing tank.

[0128] Therefore, after each batch of etching reaction is completed, 1.6L of NaOH (40% NaOH solution) and 0.205L of pure water are added accordingly (in addition, under the condition of 80°C, a certain amount of water will evaporate, which can be quantitatively added according to empirical data). In addition, when the silicon wafers are taken out by the robot arm, the liquid loss of the basket carrying the silicon wafers in each batch is a quantitative value, and the loss can be supplemented according to the initial group ratio.

[0129] It can be understood that, since the reaction is irreversible, Na2SiO3 as a product will be generated more and more as multiple batches of etching reactions proceed, and the solubility of Na2SiO3 will gradually increase. When the saturated solubility is reached, solid flocs will precipitate. In order to ensure the smooth progress of the chemical reaction, it is necessary to perform regular and quantitative drainage operations to ensure the equilibrium state of the solubility of Na2SiO3.

[0130] S5, discharging part of the chemical solution in the semiconductor process equipment according to the first discharge amount, and adjusting the concentration of the active ingredient in the chemical solution according to the first discharge amount and the first loss amount.

[0131] Specifically include:

[0132] Step 1: obtaining a second loss amount of the active ingredient caused by discharging the first discharge amount of the drug solution. Specifically, according to the initial volume of the drug solution before the silicon wafer reaction and the initial concentration of the active ingredient therein, and the current volume of the drug solution after the silicon wafer reaction, obtaining the current concentration of the active ingredient in the drug solution after the silicon wafer reaction; the product of the first discharge amount and the current concentration is taken as the second loss amount;

[0133] Exemplarily, the current amount of active ingredients in the drug solution after the silicon wafer reaction is obtained, where the current amount is the difference between the product of the initial volume and the initial concentration and the first loss amount; the ratio of the current amount to the current volume is taken as the current concentration.

[0134] Step two, obtain a second replenishing liquid with a second volume and an active ingredient concentration of a second concentration, wherein the second volume is less than or equal to the volume difference of the drug solution in the semiconductor process equipment corresponding to the mass difference, and the product of the second concentration and the second volume is the sum of the first loss amount and the second loss amount; add the second replenishing liquid to the semiconductor process equipment, such as adding it to the texturing tank of the semiconductor process equipment.

[0135] It should be noted that in other embodiments, if the concentration of the silicidation product is greater than or equal to the threshold value, a quantitative discharge operation is performed according to the first discharge amount to discharge at least part of the mixed solution in the semiconductor process equipment, and then the concentration of the active ingredient in the solution is adjusted according to the first discharge amount and the first loss amount so that the concentration of the etching solution is within a preset range.

[0136] In summary, the method for controlling the concentration of the chemical solution provided by the present invention controls the alkali concentration and the product concentration in the chemical solution within a predetermined range by means of calculation without adding any additional devices, thereby stabilizing the silicon wafer processing effect and improving the yield of the device.

[0137] Parts not described in detail in the specification of the present invention are well known to those skilled in the art.

[0138] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. It should be noted that the terms "and / or" or " / " used in this article are merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the concentration of a chemical solution, applied to semiconductor process equipment, characterized in that: The control method comprises: Obtaining the quality difference of silicon wafers before and after a preset time of reaction with a chemical solution in a semiconductor process equipment; According to the mass difference, obtaining a first loss amount of the active ingredient in the drug solution and a concentration of the silicification product; determining whether the concentration of the silicidation product is greater than or equal to a threshold; If the concentration of the silicification product is less than the threshold, adjusting the concentration of the active ingredient in the liquid medicine according to the first loss amount; the step of obtaining the first loss amount of the active ingredient in the liquid medicine and the concentration of the silicification product according to the mass difference comprises: Obtaining the first loss amount and the concentration of the silicidation product according to a proportional relationship in a chemical equation of a reaction between the silicon wafer and the active ingredient; If the concentration of the silicidation product is greater than or equal to a threshold value, part of the liquid medicine in the semiconductor process equipment is discharged according to a first discharge amount, and the concentration of the active ingredient in the liquid medicine is adjusted according to the first discharge amount and the first loss amount; the first discharge amount is a pre-set fixed discharge amount.

2. The method for controlling the concentration of a drug solution according to claim 1, characterized in that: The step of adjusting the concentration of the active ingredient in the liquid medicine according to the first loss amount comprises: obtaining a first replenishing liquid having a first volume and a first concentration of the active ingredient, wherein the first volume is less than or equal to the volume difference of the liquid medicine in the semiconductor process equipment corresponding to the mass difference, and the product of the first concentration and the first volume is the first loss amount; The first replenishing liquid is added into the semiconductor process equipment.

3. The method for controlling the concentration of a drug solution according to claim 1, characterized in that: The step of adjusting the concentration of the active ingredient in the liquid medicine according to the first discharge amount and the first loss amount comprises: Obtaining a second loss amount of the active ingredient caused by discharging the first discharge amount of the liquid medicine; Obtaining a second replenishing solution having a second volume and an active ingredient concentration of a second concentration, wherein the second volume is less than or equal to the volume difference of the drug solution in the semiconductor process equipment corresponding to the mass difference, and the product of the second concentration and the second volume is the sum of the first loss amount and the second loss amount; The second replenishing liquid is added into the semiconductor process equipment.

4. The method for controlling the concentration of a drug solution according to claim 3, characterized in that: The step of obtaining a second loss amount of the active ingredient caused by discharging the first discharge amount of the liquid medicine comprises: Obtaining a current concentration of the active ingredient in the drug solution after the silicon wafer reaction according to the initial volume of the drug solution before the silicon wafer reaction and the initial concentration of the active ingredient therein, and the current volume of the drug solution after the silicon wafer reaction; The product of the first emission amount and the current concentration is taken as the second loss amount.

5. The method for controlling the concentration of a drug solution according to claim 4, characterized in that: The step of obtaining the current concentration of the active ingredient in the medicine solution after the silicon wafer reaction according to the initial volume of the medicine solution before the silicon wafer reaction and the initial concentration of the active ingredient therein, and the current volume of the medicine solution after the silicon wafer reaction comprises: Obtaining a current amount of the active ingredient in the drug solution after the silicon wafer reacts, wherein the current amount is a difference between a product of the initial volume and the initial concentration and the first loss amount; The ratio of the current amount to the current volume is taken as the current concentration.

6. The method for controlling the concentration of a drug solution according to any one of claims 1 to 5, characterized in that: The drug solution includes the active ingredient and a solvent, and the active ingredient includes hydroxide ions.

7. A semiconductor process equipment, which is used for cleaning or etching silicon wafers with a chemical solution, characterized in that: The semiconductor process equipment includes a processor and a memory, a mass acquisition component and a concentration adjustment component respectively coupled to the processor, wherein the memory stores program instructions, and the processor is capable of executing the program instructions and cooperating with the mass acquisition component and the concentration adjustment component to implement the method for controlling the concentration of the drug solution as described in any one of claims 1-6.

8. The semiconductor process equipment according to claim 7, characterized in that: The semiconductor process equipment includes a tank-type wet cleaning equipment or a tank-type wet texturing equipment.

9. A computer-readable storage medium, characterized in that: The storage medium stores program instructions, and the program instructions can be executed by a processor to implement the method for controlling the concentration of the drug solution as described in any one of claims 1-6.

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