Semiconductor process parameter determination method, detection method and semiconductor processing equipment

Abstract

The present application discloses a method for determining semiconductor process parameters, a detection method, and semiconductor processing equipment. The method includes: S1, calculating the first leakage rate of the chamber based on the current preset air intake flow rate and the pressure reducing valve pressure, and calculating the second leakage rate of the chamber based on the current preset radio frequency starting power; S2, calculating the ultimate vacuum degree of the chamber based on the background leakage rate, the first leakage rate, the second leakage rate, and the pumping speed of the vacuum pump of the chamber; S3, if the ultimate vacuum degree is less than or equal to the current preset target chamber pressure, then using the preset air intake flow rate, the preset radio frequency starting power, and the preset target chamber pressure as semiconductor process parameters. This method does not require an actual pumping experiment to determine whether the current equipment vacuum system can control the chamber to the target chamber pressure based on the current preset process parameters. Instead, the conclusion is drawn directly through calculation and processing by the system, which not only reduces manpower and material costs, but also has high efficiency.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a method for determining and detecting semiconductor process parameters and semiconductor processing equipment. Background Art

[0002] A necessary condition for plasma-related equipment to produce low-temperature plasma is vacuum, that is, plasma-related process equipment needs to evacuate the chamber to a certain vacuum in order to obtain low-temperature plasma. Therefore, the vacuum system is an essential component in plasma equipment. Normally, the vacuum system consists of a vacuum pump (including mechanical pumps, molecular pumps, and cold pumps, etc.) and a swing valve. The gas pressure in the chamber can be adjusted by adjusting the opening of the swing valve. When the swing valve is opened to the maximum, the vacuum system's vacuum pumping capacity reaches the maximum / limit value. Under the same chamber pressure, the greater the intake air flow rate, the higher the vacuum system's vacuum pumping capacity requirements, that is, a larger swing valve opening is required.

[0003] Taking a plasma etcher as an example, lower chamber pressure improves the plasma's mean free path (enabling deep silicon etching) and etching uniformity. On the other hand, a higher air flow rate can achieve a faster etching rate, thereby increasing production capacity and reducing costs. Because the process involves simultaneous vacuum pumping and RF ignition, determining whether low chamber pressure and high air flow exceed the capabilities of existing equipment (i.e., the vacuum system) in such a complex situation—in other words, whether the swing valve can function properly—is a significant challenge.

[0004] In the related art, it is necessary to manually perform intake pressure control and conduct repeated tests to determine the normal pressure control range, which not only wastes manpower and is costly, but also has low efficiency. Summary of the Invention

[0005] In response to the above technical problems, the present application provides a method for determining semiconductor process parameters, a detection method and semiconductor processing equipment, which can improve the problems of high cost and low efficiency of existing methods for determining semiconductor process parameters.

[0006] To solve the above technical problems, in a first aspect, an embodiment of the present application provides a method for determining semiconductor process parameters, the method comprising:

[0007] S1, calculating a first leakage rate of the chamber according to a current preset intake flow rate and a pressure reducing valve pressure, and calculating a second leakage rate of the chamber according to a current preset radio frequency starting power;

[0008] S2. Calculating the ultimate vacuum degree of the chamber according to the background leak rate of the chamber, the first leak rate, the second leak rate, and the pumping speed of the vacuum pump;

[0009] S3. If the ultimate vacuum degree is less than or equal to the current preset target chamber pressure, the preset intake flow rate, the preset RF starting power and the preset target chamber pressure are used as the semiconductor process parameters.

[0010] Optionally, after S2, the step further includes:

[0011] S4. If the ultimate vacuum degree is greater than the preset target chamber pressure, perform at least one parameter adjustment step from (a) to (c) below, update the adjusted parameter to the current value, and return to S1; wherein the parameter adjustment step includes:

[0012] (a) reducing the preset intake air flow rate;

[0013] (b) reducing the preset radio frequency starting power;

[0014] (c) increasing the preset target cavity pressure.

[0015] Optionally, the first leakage rate Q F The calculation method is:

[0016] Q F =F g *p s *1.127×10 -4 and / or,

[0017] The second leakage rate Q P The calculation method is: Q P =(2 / 3)*η*ΔP A ,

[0018] Among them, F g is the equivalent intake flow rate of the preset intake flow rate, p s is the pressure reducing valve pressure, ΔP A is the preset RF starting power, and η is the effective ratio constant.

[0019] Optionally, the calculation method of the equivalent intake air flow is:

[0020] F g =Σ[F i / (M i / M0) 0.5 ] (13)

[0021] Among them, F i is the preset intake flow rate of the i-th gas, M i is the molecular weight of the i-th gas actually inhaled, and M0 is the molecular weight of the reference gas.

[0022] In a second aspect, an embodiment of the present application further provides a method for detecting a vacuum system, the method comprising:

[0023] S5. Determine the semiconductor process parameters according to the method described in the above embodiments;

[0024] S6. Pumping down the chamber according to the semiconductor process parameters to obtain an actual pumping time for pumping down the chamber from an initial chamber pressure to a current preset intermediate chamber pressure, wherein the preset intermediate chamber pressure is less than the initial chamber pressure and greater than or equal to the preset target chamber pressure;

[0025] S7, calculating the theoretical pumping time for pumping the chamber from the initial chamber pressure to the preset intermediate chamber pressure;

[0026] S8. If the ratio of the actual pumping time to the theoretical pumping time is greater than a preset threshold, it is determined that the vacuum system is abnormal.

[0027] Optionally, after S7, the step further includes:

[0028] S9. If the ratio of the actual pumping time to the theoretical pumping time is less than or equal to the preset threshold, reducing the preset intermediate chamber pressure by a preset pressure value;

[0029] S10 , if the preset intermediate cavity pressure after adjustment is greater than the preset target cavity pressure, then the preset intermediate cavity pressure after adjustment is updated as the current preset intermediate cavity pressure, and the process returns to S6 .

[0030] Optionally, after S9, the step further includes:

[0031] S11 , if the preset intermediate cavity pressure after being adjusted down is less than or equal to the preset target cavity pressure, it is determined that the vacuum system is normal.

[0032] Optionally, the preset threshold value ranges from 1 to 5.

[0033] Optionally, the preset intermediate cavity pressure is an intermediate value between the initial cavity pressure and the preset target cavity pressure.

[0034] In a third aspect, an embodiment of the present application further provides a semiconductor processing device, which executes the method described in the above embodiments to determine the semiconductor process parameters, and executes the corresponding semiconductor processing process according to the semiconductor process parameters.

[0035] As described above, the method for determining semiconductor process parameters of the present application establishes an analytical calculation model that divides the factors affecting the ultimate vacuum degree of the chamber into three parts: (1) the background leak rate of the chamber; (2) the intake flow rate of the gas delivered to the chamber, which can be converted into a corresponding leak rate, namely the first leak rate; and (3) the change in leak rate caused by the increase in the gas temperature and chamber pressure in the chamber due to RF ignition, namely the second leak rate. The ultimate vacuum degree of the chamber can then be calculated using the background leak rate, the first leak rate, and the second leak rate. If the calculated ultimate vacuum degree is less than or equal to the current preset target chamber pressure, it means that under the current process parameters, the vacuum pump can pump the chamber pressure to the target chamber pressure. Therefore, the preset intake flow rate, the preset RF ignition power, and the preset target chamber pressure can be used as semiconductor process parameters. This method does not require an actual pumping experiment to determine whether the current equipment vacuum system can control the chamber to the target chamber pressure based on the current preset process parameters. Instead, it directly draws conclusions through system calculation processing, which not only reduces manpower and material costs but also has high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings herein are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without inventive work.

[0037] Figure 1 This is a flow chart of a method for determining semiconductor process parameters provided by an embodiment of the present application;

[0038] Figure 2 It is a flow chart of a vacuum system detection method provided in an embodiment of the present application.

[0039] The purpose of this application, its features, and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings. The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and the accompanying text are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of this application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0040] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0041] It should be noted that, in this document, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or different meanings, and their specific meanings need to be determined by their explanation in the specific embodiment or further combined with the context of the specific embodiment.

[0042] It should be understood that although the terms "first," "second," "third," etc. may be used herein to describe various types of information, such information should not be limited to these terms. These terms are merely used to distinguish information of the same type from one another. For example, first information may be referred to as second information, and similarly, second information may be referred to as first information without departing from the scope of this disclosure.

[0043] Depending on the context, the word "if" as used herein can be interpreted as "at the time of" or "when" or "in response to determining". Furthermore, as used in this article, the singular forms "a", "an" and "the" are intended to also include the plural forms, unless there is an opposite indication in the context. It should be further understood that the terms "comprising" and "including" indicate the presence of the described features, steps, operations, elements, components, projects, kinds, and / or groups, but do not exclude the existence, occurrence or addition of one or more other features, steps, operations, elements, components, projects, kinds, and / or groups. The terms "or", "and / or", "including at least one of the following" etc. used in this application can be interpreted as inclusive, or mean any one or any combination. For example, “comprising at least one of the following: A, B, C” means “any of the following: A; B; C; A and B; A and C; B and C; A and B and C”; and for another example, “A, B or C” or “A, B and / or C” means “any of the following: A; B; C; A and B; A and C; B and C; A and B and C”. An exception to this definition will occur only when a combination of elements, functions, steps or operations are inherently mutually exclusive in some manner.

[0044] It should be understood that, although the various steps in the flowchart in the embodiment of the present application are shown in sequence according to the indication of the arrows, these steps are not necessarily performed in sequence in the order indicated by the arrows. Unless clearly stated herein, the execution of these steps is not strictly limited in order, and they can be performed in other orders. Moreover, at least a portion of the steps in the figure may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and their execution order is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0045] Taking a plasma etcher as an example, a lower chamber pressure is beneficial to improving the mean free path of the plasma (to achieve deep silicon etching) and etching uniformity. On the other hand, a higher air intake flow rate can achieve a faster etching rate, thereby increasing production capacity and reducing costs. When a plasma device generates low-temperature plasma, it takes in air while evacuating the chamber, and is also accompanied by radio frequency ignition. The applicant's research found that the increase in gas temperature caused by radio frequency ignition will cause the pressure in the chamber to increase, thereby further affecting the air extraction. Since the above-mentioned influencing factors are numerous and have a certain influence on each other, it is currently necessary to manually control the air intake pressure and conduct repeated tests to draw conclusions in order to determine whether the low chamber pressure and high air intake flow rate exceed the capabilities of existing equipment (i.e., vacuum systems). This is not only a waste of manpower and high cost, but also inefficient. Based on this, the present application provides a method for determining semiconductor process parameters, a detection method, and semiconductor processing equipment.

[0046] See also Figure 1 , Figure 1 10 is a flow chart of a method for determining semiconductor process parameters provided in an embodiment of the present application, the method including steps 101-103.

[0047] 101. Calculate a first leakage rate of the chamber according to a current preset intake flow rate and a pressure reducing valve pressure, and calculate a second leakage rate of the chamber according to a current preset radio frequency starting power.

[0048] 102. Calculate the ultimate vacuum degree of the chamber based on the background leak rate, the first leak rate, the second leak rate, and the pumping speed of the vacuum pump.

[0049] 103. If the ultimate vacuum degree is less than or equal to the current preset target chamber pressure, the preset intake flow rate, the preset RF starting power and the preset target chamber pressure are used as semiconductor process parameters.

[0050] The process parameters of plasma-related equipment can be set manually, in which the gas cylinder containing the gas is connected to the process chamber through a gas pipeline, and the pressure reducing valve can be set on the gas pipeline. The pressure of the pressure reducing valve is basically a fixed value under the premise of ensuring safety, and it will basically not be changed after setting. For example, for gases that are easy to liquefy (such as octafluorocyclobutane), the pressure reducing valve pressure can be set to 5psi, and for gases that are not easy to liquefy, it can be set to 30psi. The target cavity pressure is set according to different process requirements or product types. For example, different target cavity pressures can be set for chemical / physical vapor deposition, deep silicon etching, edge etching, etc. Whether the current equipment vacuum system can make the pressure in the chamber reach the target cavity pressure has a significant impact on the setting of the intake flow rate and the RF starting power.

[0051] In some application scenarios, process parameters such as inlet gas flow rate, RF ignition power, and target chamber pressure can be set on the semiconductor processing equipment's UI. The system then calculates and analyzes whether the chamber pressure can be controlled to the target pressure based on the current equipment vacuum system. Currently, there's no scientific and convenient way to verify this, other than conducting actual pumping experiments.

[0052] The present embodiment establishes an analytical calculation model that divides the factors affecting the ultimate vacuum degree of a chamber into three parts: (1) the chamber's background leak rate; (2) the inlet flow rate of the gas delivered to the chamber, which can be converted into a corresponding leak rate, namely the first leak rate; and (3) the change in leak rate caused by the increase in gas temperature and chamber pressure caused by RF ignition, namely the second leak rate. The overall leak rate of the chamber can then be calculated from the background leak rate, the first leak rate, and the second leak rate, and the ultimate vacuum degree of the chamber can be calculated from the overall leak rate.

[0053] It should be noted that the leakage rate refers to the rate at which the chamber vacuum is destroyed, that is, the amount of gas molecules entering the chamber from the leakage point in the chamber per unit time. Theoretically, there is no absolutely closed space, that is, the vacuum system will definitely have a leakage rate, but the degree will vary.

[0054] As is common knowledge in this field, the calculation formula for the chamber's ultimate vacuum degree p0 is:

[0055] p0=Q / S (1)

[0056] Among them, Q is the chamber leakage rate, S is the pumping speed of the vacuum pump, and is an inherent parameter of the vacuum pump.

[0057] If the calculated ultimate vacuum degree p0 is less than or equal to the current preset target chamber pressure p F , it indicates that under the current process parameters, the vacuum pump can pump the chamber pressure to the target pressure. Therefore, the preset inlet gas flow rate, preset RF ignition power, and preset target pressure can be used as semiconductor process parameters. This method eliminates the need for actual pumping experiments to determine whether the current equipment vacuum system can control the chamber to the target pressure based on the preset process parameters. Instead, the system directly calculates and processes the results, which not only reduces labor and material costs but also improves efficiency.

[0058] It should be noted that, since the present application is to calculate the ultimate vacuum degree of the chamber, the peak value of the pumping speed of the vacuum pump can be used for calculation.

[0059] Furthermore, the above step 101 may further include:

[0060] 104. If the ultimate vacuum degree is greater than the preset target chamber pressure, perform at least one parameter adjustment step from (a) to (c) below, update the adjusted parameter to the current value, and return to S101; wherein the parameter adjustment step includes:

[0061] (a) reducing the preset intake air flow rate;

[0062] (b) reducing the preset radio frequency starting power;

[0063] (c) increasing the preset target cavity pressure.

[0064] That is, when p0>p FIf the target chamber pressure is too low, or other parameters are improperly set, the vacuum pump cannot pump the chamber to the target pressure. If the process allows, the target chamber pressure can be set above the calculated ultimate vacuum level p0. Alternatively, adjust the preset intake flow rate, the preset RF ignition power, or two or three of the three simultaneously, until the recalculated ultimate vacuum level is less than or equal to the target chamber pressure.

[0065] It should be noted that the background leakage rate of the chamber Q B It is an inherent parameter of the chamber and has a certain value when the equipment is intact and can operate normally and the equipment status does not change significantly (such as no cavity opening for cleaning, etc.). It can be measured in advance by a sealing tester, such as a helium mass spectrometer leak detector.

[0066] The embodiment of the present application also provides a method for calculating and processing the first leak rate and the second leak rate.

[0067] The first leak rate Q F The conversion is performed by the intake flow F, that is, the intake is regarded as a leak rate for conversion processing, and the current preset intake flow F (unit: sccm) and the pressure reducing valve pressure p s (Unit: psi, one atmosphere is approximately equal to 15 psi) is calculated, where the pressure of the gas entering the chamber is approximately equal to the pressure at the outlet of the pressure reducing valve (i.e., the pressure of the pressure reducing valve). According to formula (1), the first leak rate (SI unit: Pa·m 3 ·s -1 ) is calculated as:

[0068] Q F =F*p s *1.127×10 -4 (2)

[0069] It is understandable that since the intake flow rate represents the volume of gas flowing into the chamber per unit time, and the gas volume is different under different pressures, the intake flow rate and the pressure reducing valve pressure need to be multiplied when calculating the first leak rate.

[0070] The second leak rate can be calculated based on the current preset RF ignition power. RF ignition causes an increase in temperature and pressure within the chamber, ultimately affecting the chamber's leak rate. The processing method in this embodiment of the application is to convert the pressure increase into a corresponding leak rate (the second leak rate), as follows.

[0071] First, formulas (3) to (5) are common knowledge. The formula for the average translational energy of a single gas molecule is:

[0072] ε k=(1 / 2)*mv 2 =(3 / 2)*kT (3)

[0073] Among them, ε k is the average translational energy of a single gas molecule, m is the mass of a single gas molecule, v is the average translational velocity of a single gas molecule, k is the Boltzmann constant, and T is the macroscopic temperature (the temperature in the chamber).

[0074] The ideal gas state equation is:

[0075] pV=nRT (4)

[0076] Where p is the chamber pressure, V is the chamber volume, n is the amount of gas in the chamber (mol), and R is the ideal gas constant.

[0077] The Boltzmann constant k and the ideal gas constant R satisfy the following formula (5):

[0078] k=R / N A (5)

[0079] Among them, N A is Avogadro's constant.

[0080] After RF ignition, assuming that the pressure change in the chamber is Δp and the temperature change is ΔT, the kinetic energy change Δε of all gases in the chamber can be obtained according to formulas (3) to (5):

[0081] Δε=Δε k *n*N A =(3 / 2)*kΔT*n*N A =(3 / 2)*Δp*V (6)

[0082] The increase in the average kinetic energy of the gas is caused by the RF starting power. Most of the RF starting power only produces thermal effects, that is, the coil current generates Joule heat. Only about 15% of the power forms an alternating electromagnetic field and acts on the gas in the chamber. Most of this 15% of power is used for gas dissociation to form free radicals, and only a small part is used for ionization excitation and acceleration of ions to generate kinetic energy for gas molecular motion. Therefore, the effective power in the RF starting power is:

[0083] ΔP E =η*ΔP A (7)

[0084] Where ΔP A is the RF starting power, ΔP Eis the effective power in the RF starting power, which is used to generate kinetic energy for molecular motion. η is the effective ratio constant, which can be determined based on experiments, for example, it can be determined to be 0.3%, 0.5%, 0.8%, 1%, etc.

[0085] According to the law of conservation of energy, the increase in the average kinetic energy of the gas after RF ignition is equal to the effective power in the RF ignition power, which can be referred to the following formula:

[0086] ΔP E =Δε / t (8)

[0087] Where t is the time the RF starting power is applied.

[0088] According to formulas (6) to (8), the pressure change in the chamber after RF ignition is Δp:

[0089] Δp=(2 / 3)*η*ΔP A *t / V (9)

[0090] Convert the increase in chamber pressure after RF ignition into the second leakage rate Q p , combined with formula (9), Q p The calculation formula is as follows:

[0091] Q p =Δp*V / t=(2 / 3)*η*ΔP A (10)

[0092] According to formulas (1), (2) and (10), the ultimate vacuum p0 of the chamber can be calculated:

[0093] p0=(Q B +Q F +Q p ) / S=[Q B +F*p s *1.127×10 -4 +(2 / 3)*η*ΔP A ] / S (11)

[0094] It should be noted that the pumping speed S of the vacuum pump is generally based on the pumping speed of the reference gas (g), such as nitrogen. Due to the different molecular weights of different gases, the preset intake flow rate F of the gas can be equivalent to the flow rate of the reference gas, and the equivalent intake flow rate F g for:

[0095] F g =F / (M / M0) 0.5 (12)

[0096] Where M is the molecular weight of the actual intake gas, and M0 is the molecular weight of the reference gas.

[0097] If there are multiple different gases for intake, the formula (12) can be summed:

[0098] F g =Σ[F i / (M i / M0) 0.5 ] (13)

[0099] Among them, F i is the preset intake flow rate of the i-th gas, M i is the molecular weight of the i-th gas actually inhaled.

[0100] According to formulas (11) and (13), the ultimate vacuum p0 of a chamber with multiple gases as inlet can be obtained:

[0101] p0={Q B +Σ[p si *F i / (M i / M0) 0.5 ]*1.127×10 -4 +(2 / 3)*η*ΔP A} / S (14)

[0102] It should be noted that in the above formula, the unit of intake air flow is sccm, p si is the pressure reducing valve pressure corresponding to the i-th gas, and its unit is psi. The other physical quantities are all in the International System of Units.

[0103] Formula (14) can be used to automatically calculate the chamber's ultimate vacuum degree p0 based on the current preset intake flow rate and preset RF starting power, and further determine whether the chamber can be normally controlled based on its relationship with the preset target chamber pressure.

[0104] Based on the method for determining semiconductor process parameters in the above embodiment, the present application also provides a method for detecting a vacuum system, which can be used to detect whether the vacuum system of a chamber is working normally and whether it needs to be repaired and maintained. Figure 2 , Figure 2 20 is a flow chart of a vacuum system detection method provided in an embodiment of the present application, the method including steps 201-204.

[0105] 201. Determine semiconductor process parameters.

[0106] This step can refer to the method of the previous embodiment (e.g., steps 101-104) to determine the preset intake air flow rate, preset RF ignition power, and preset target chamber pressure, and thus will not be described in detail. Based on the process parameters determined by the above method, the chamber vacuum system can theoretically operate normally.

[0107] 202. Pump down the chamber according to the determined semiconductor process parameters to obtain an actual pumping time for pumping down the chamber from an initial chamber pressure to a current preset intermediate chamber pressure, wherein the preset intermediate chamber pressure is less than the initial chamber pressure and greater than or equal to a preset target chamber pressure.

[0108] When performing actual air extraction testing, you can first determine the current preset intermediate cavity pressure p m , p m The value is less than the initial cavity pressure p i , and is greater than or equal to the preset target cavity pressure p f .

[0109] For example, when p f <p m <p i When the pressure in the chamber is pumped down to p m It is possible that an abnormality in the vacuum system can be found at this time, and there is no need to pump to the end point p f As an example, p m =p f +(p i -p f ) / 2, that is, the preset intermediate cavity pressure is the middle value between the preset target cavity pressure and the initial cavity pressure.

[0110] When p m =p f When the chamber pressure is directly reduced from the initial chamber pressure p i Pump to the preset target chamber pressure p f That is, in some applications, when p i With p f This method can be used when the difference is not large and the pumping time is relatively short.

[0111] When the chamber is pumped from the initial chamber pressure to the current preset intermediate chamber pressure, the actual pumping time t is recorded. r It is understandable that the setting of the preset intermediate cavity pressure can save verification time and reduce detection costs in some cases.

[0112] Calculate the theoretical pumping time required to pump the chamber from the initial chamber pressure to the preset intermediate chamber pressure.

[0113] The chamber starts from the initial chamber pressure p i Pump to the preset intermediate chamber pressure p m Theoretical pumping time t used c , the calculation formula can refer to the following well-known formula in the art:

[0114] t c =2.3*(V / S)*lg[(pi -p0) / (p m -p0)] (15)

[0115] Where V is the volume of the chamber, S is the pumping speed of the vacuum pump, and p0 is the ultimate vacuum degree of the chamber, which can be calculated according to formula (14).

[0116] 204. If the ratio of the actual pumping time to the theoretical pumping time is greater than a preset threshold, it is determined that the vacuum system is abnormal.

[0117] The actual pumping time t from the initial chamber pressure to the current preset intermediate chamber pressure is obtained. r and theoretical pumping time t c Then, we further calculate the ratio r between the two:

[0118] r=t r / t c (16)

[0119] When r is greater than the preset threshold, it means that the actual pumping time is too long. This may be due to insufficient sealing of the vacuum system or abnormal pumping speed of the vacuum pump, or other reasons. Therefore, it can be determined that the vacuum system is abnormal.

[0120] It is understood that the larger the preset threshold, the greater the tolerance for vacuum system errors, while the smaller the preset threshold, the higher the maintenance requirements for the vacuum system. As an example, the preset threshold can range from 1 to 5, for example, the preset threshold can be 1.0, 1.2, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, etc. The preset threshold is preferably 1.5, which ensures that the vacuum system is in a highly reliable operating state.

[0121] The embodiment of the present application is based on the process parameters (preset intake flow rate, preset RF starting power and preset target chamber pressure) determined by the method of the aforementioned embodiment, and combined with the actual pumping operation, it is possible to detect the current vacuum system of the chamber, determine whether it can work normally, and provide guidance on whether the current vacuum system of the chamber requires maintenance.

[0122] As an example, see Figure 2 , step 204 may further include steps 205 and 206.

[0123] 205. If the ratio of the actual pumping time to the theoretical pumping time is less than or equal to the preset threshold, the preset intermediate cavity pressure is reduced by a preset pressure value.

[0124] When r is less than or equal to the preset threshold, it means that the current process parameters can meet the requirements of pumping the chamber from the initial chamber pressure to the current preset intermediate chamber pressure. Therefore, it can be further verified whether the current process parameters meet the requirements of the current preset intermediate chamber pressure to the preset target chamber pressure p. f The specific verification process can also be carried out in stages, for example, the preset intermediate cavity pressure is adjusted down by a preset pressure value to gradually approach the preset target cavity pressure, wherein the preset pressure value can be set according to actual conditions.

[0125] As an example, we can assign p m =p m -1mTorr.

[0126] 206 . If the reduced preset intermediate cavity pressure is greater than the preset target cavity pressure, the reduced preset intermediate cavity pressure is updated as the current preset intermediate cavity pressure, and the process returns to step 202 .

[0127] If the preset intermediate cavity pressure after the adjustment is greater than the preset target cavity pressure, it means that the currently verified preset intermediate cavity pressure is still within the range to be verified (p f , p i ), the reduced preset intermediate cavity pressure is updated as the current preset intermediate cavity pressure, and then the process returns to step 202 to perform the next cycle of verification.

[0128] Furthermore, step 207 may be included after step 205 or 206.

[0129] 207. If the preset intermediate cavity pressure after adjustment is less than or equal to the preset target cavity pressure, it is determined that the vacuum system is normal.

[0130] If the preset intermediate cavity pressure after the adjustment is less than or equal to the preset target cavity pressure, it means that the currently verified preset intermediate cavity pressure has exceeded the range to be verified (p f , p i ), and the previous process has verified that the current process parameters can meet the requirements for pumping the chamber from the initial chamber pressure to the current preset intermediate chamber pressure. Therefore, it can be determined that the vacuum system is normal.

[0131] For example, consider a high-density plasma chemical vapor deposition (HDCPCVD) system with a gas cylinder pressure relief valve of 15 psi, a vacuum pump (based on N2) pumping speed of 3200 L / s, and a chamber volume of 115 L. Under a specific process recipe (preset inlet flow rate, preset RF ignition power, and preset target chamber pressure), the preset inlet flow rate is converted to an N2 inlet flow rate of 800 sccm. The chamber's background leak rate is negligible relative to this inlet flow rate. At a specific sub-step, before RF ignition, the ultimate vacuum can be calculated:

[0132] p0=800*15*1.127×10 -4 / (3200*1000)=0.4225Pa=3.177mTorr

[0133] If the preset target chamber pressure in the process recipe is lower than 3 mTorr, it means that the pressure cannot be controlled normally and at least one of the three parameters in the process recipe needs to be adjusted.

[0134] If the target chamber pressure in the process recipe is 5 mTorr, which is greater than the calculated vacuum limit, then the pressure control is normal. At this point, further testing can be performed to determine if the vacuum system is functioning properly.

[0135] For example, if the initial chamber pressure before a sub-step is 40 mTorr, the theoretical pumping time required to pump down from 40 mTorr to 5 mTorr is:

[0136] t=2.3*(115 / 3200)*lg[(40-3.177) / (5-3.177)]=0.108s;

[0137] Then, actual pumping is performed, and the preset target chamber pressure of 5 mTorr can be achieved when the actual pumping time is 0.15 s.

[0138] The r value is calculated, r = 0.15 / 0.108 = 1.38 < 1.5 (preset threshold), indicating that the equipment vacuum system is working normally and no maintenance or repair is required.

[0139] An embodiment of the present application further provides a semiconductor processing device, which executes the method described in the above embodiments to determine semiconductor process parameters and executes a corresponding semiconductor processing process according to the semiconductor process parameters.

[0140] The semiconductor processing equipment is a plasma-related equipment. As some examples, the semiconductor processing equipment may be a plasma etching equipment, a plasma-enhanced chemical vapor deposition equipment, a physical vapor deposition equipment, etc.

[0141] The above describes in detail a method for determining and detecting semiconductor process parameters, as well as semiconductor processing equipment, provided by this application. This article uses specific examples to illustrate the principles and implementation methods of this application. It should be noted that in this application, the descriptions of each embodiment have their own emphases. For portions not detailed or recorded in a particular embodiment, please refer to the relevant descriptions of other embodiments.

[0142] The various technical features of the technical solution of this application can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0143] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for determining semiconductor process parameters, characterized in that: The method comprises: S1, calculating a first leakage rate of the chamber according to a current preset intake flow rate and a pressure reducing valve pressure, and calculating a second leakage rate of the chamber according to a current preset radio frequency starting power; S2. Calculating the ultimate vacuum degree of the chamber according to the background leak rate of the chamber, the first leak rate, the second leak rate, and the pumping speed of the vacuum pump; S3. If the ultimate vacuum degree is less than or equal to the current preset target chamber pressure, the preset intake flow rate, the preset RF starting power and the preset target chamber pressure are used as the semiconductor process parameters.

2. The method according to claim 1, characterized in that The S2 also includes: S4. If the ultimate vacuum degree is greater than the preset target chamber pressure, perform at least one parameter adjustment step from (a) to (c) below, update the adjusted parameter to the current value, and return to S1; wherein the parameter adjustment step includes: (a) reducing the preset intake air flow rate; (b) reducing the preset radio frequency starting power; (c) increasing the preset target cavity pressure.

3. The method according to claim 1 or 2, characterized in that The first leakage rate Q F The calculation method is: Q F =F g *p s *1.127×10 -4 and / or, The second leakage rate Q P The calculation method is: Q P =(2 / 3)*η*ΔP A , Among them, F g is the equivalent intake flow rate of the preset intake flow rate, p s is the pressure reducing valve pressure, ΔP A is the preset RF starting power, and η is the effective ratio constant.

4. The method according to claim 3, characterized in that The calculation method of the equivalent intake air flow is: F g =Σ[F i / (M i / M0) 0.5 ] (13) Among them, F i is the preset intake flow rate of the i-th gas, M i is the molecular weight of the i-th gas actually inhaled, and M0 is the molecular weight of the reference gas.

5. A method for detecting a vacuum system, characterized in that: The method comprises: S5. Determine the semiconductor process parameters according to the method according to any one of claims 1 to 4; S6. Pumping down the chamber according to the semiconductor process parameters to obtain an actual pumping time for pumping down the chamber from an initial chamber pressure to a current preset intermediate chamber pressure, wherein the preset intermediate chamber pressure is less than the initial chamber pressure and greater than or equal to the preset target chamber pressure; S7, calculating the theoretical pumping time for pumping the chamber from the initial chamber pressure to the preset intermediate chamber pressure; S8. If the ratio of the actual pumping time to the theoretical pumping time is greater than a preset threshold, it is determined that the vacuum system is abnormal.

6. The method according to claim 5, characterized in that The S7 further includes: S9. If the ratio of the actual pumping time to the theoretical pumping time is less than or equal to the preset threshold, reducing the preset intermediate chamber pressure by a preset pressure value; S10 , if the preset intermediate cavity pressure after adjustment is greater than the preset target cavity pressure, then the preset intermediate cavity pressure after adjustment is updated as the current preset intermediate cavity pressure, and the process returns to S6 .

7. The method according to claim 6, characterized in that The S9 and subsequent steps also include: S11 , if the preset intermediate cavity pressure after being adjusted down is less than or equal to the preset target cavity pressure, it is determined that the vacuum system is normal.

8. The method according to claim 5, characterized in that The preset threshold value ranges from 1 to 5.

9. The method according to claim 5, characterized in that The preset intermediate cavity pressure is an intermediate value between the initial cavity pressure and the preset target cavity pressure.

10. A semiconductor processing device, characterized in that: The semiconductor processing equipment executes the method according to any one of claims 1 to 4 to determine the semiconductor process parameters, and executes a corresponding semiconductor processing process according to the semiconductor process parameters.

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