Simulation method of epitaxial process

Abstract

An epitaxy process simulation method, comprising: obtaining an epitaxy process to be simulated, the epitaxy process to be simulated comprising a plurality of epitaxy stages to be simulated, each epitaxy stage to be simulated having a corresponding initial epitaxy time rate relationship model; obtaining a plurality of groups of epitaxy process parameters, each epitaxy process parameter comprising an epitaxy rate and an epitaxy time; fitting the initial epitaxy time rate relationship model of any of the epitaxy stages to be simulated according to the epitaxy rate and the epitaxy time in at least one group of epitaxy process parameters, to obtain a corresponding reference epitaxy time rate relationship model of the epitaxy stage to be simulated; and obtaining a simulated epitaxy filling amount of the epitaxy process to be simulated according to the reference epitaxy time rate relationship models corresponding to the plurality of epitaxy stages to be simulated. The epitaxy process simulation method improves the adjustment mode of the deep trench filling process, simplifies the adjustment steps of the filling process, shortens the process adjustment time, and improves the process adjustment efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, in particular to a simulation method of epitaxy process. BACKGROUND

[0002] Deep trench super junction device is a kind of power device with wide application, which has the characteristics of high current density and low on-resistance per unit area, and has attracted the attention of the semiconductor industry.

[0003] As a crucial step in the process of deep trench super junction, the filling effect and concentration control of super junction epitaxial filling (SJ-EPI) will affect the performance of super junction device. With the feature size of deep trench super junction becoming smaller and smaller, the requirement for epitaxial filling capability in the forming process is also getting higher and higher.

[0004] In the process of filling deep trench to form deep trench super junction, too much or too little filling is easy to produce dislocation or gap defects, and too fast filling is easy to cause premature sealing and produce hole defects. However, in the existing process, in order to find the appropriate filling condition, the steps of adjusting the epitaxial filling process are complex and the efficiency is low, which leads to a large time consumption and high cost of process adjustment. SUMMARY

[0005] The technical problem solved by the present application is to provide a simulation method of epitaxy process, which improves the adjustment method of deep trench filling process, simplifies the adjustment steps of filling process, shortens the process adjustment time and improves the process adjustment efficiency.

[0006] To solve the above technical problems, the technical scheme of the present application provides a simulation method of epitaxy process, comprising: obtaining a to-be-simulated epitaxy process, the to-be-simulated epitaxy process comprising a plurality of to-be-simulated epitaxy stages, each to-be-simulated epitaxy stage having a corresponding initial epitaxial time rate relationship model; obtaining a plurality of sets of epitaxial process parameters, each epitaxial process parameter comprising an epitaxial rate and an epitaxial time; fitting the initial epitaxial time rate relationship model of any to-be-simulated epitaxy stage according to the epitaxial rate and the epitaxial time in at least one set of epitaxial process parameters, to obtain a reference epitaxial time rate relationship model corresponding to the to-be-simulated epitaxy stage; and obtaining a simulation epitaxial filling amount of the to-be-simulated epitaxy process according to the reference epitaxial time rate relationship models corresponding to the plurality of to-be-simulated epitaxy stages.

[0007] Optionally, the method for obtaining the epitaxial rate in the plurality of sets of epitaxial process parameters comprises: providing a substrate; performing a plurality of preliminary epitaxial processes on the substrate, each preliminary epitaxial process having a corresponding epitaxial process parameter; obtaining the performing time t and the epitaxial thickness h of each preliminary epitaxial process; and obtaining each epitaxial rate v = h / t according to the performing time t and the epitaxial thickness h.

[0008] Optionally, the substrate surface is planar.

[0009] Optionally, the number of the obtained epitaxial rates is greater than or equal to 4.

[0010] Optionally, the epitaxial stage to be simulated comprises a single-rate epitaxial process, a step-rate epitaxial process, or a gradual-rate epitaxial process.

[0011] Optionally, when the epitaxial stage to be simulated is a single-rate epitaxial process, the epitaxial rate of the epitaxial stage to be simulated is constant.

[0012] Optionally, when the epitaxial stage to be simulated is a single-rate epitaxial process, the initial epitaxial time-rate relationship model is R(T)=d, where R is the epitaxial rate and T is the epitaxial time.

[0013] Optionally, when the epitaxial stage to be simulated is a step-rate epitaxial process, the epitaxial stage to be simulated comprises a first stage and a second stage, the epitaxial rate of the first stage is constant, the epitaxial rate of the second stage is constant, and the epitaxial rate of the first stage is greater than the epitaxial rate of the second stage.

[0014] Optionally, the first stage has a corresponding initial first epitaxial time-rate relationship model R(T)=e(T0≤T<T1), and the second stage has a corresponding initial second epitaxial time-rate relationship model R(T)=f(T1≤T<T2), where R is the epitaxial rate and T is the epitaxial time.

[0015] Optionally, when the epitaxial stage to be simulated is a gradual-rate epitaxial process, the epitaxial rate of the epitaxial stage to be simulated increases or decreases with an increase in the epitaxial time.

[0016] Optionally, when the epitaxial stage to be simulated is a gradual-rate epitaxial process, the initial epitaxial time-rate relationship model is R(T)=a*T 2 +b*T+c, where R is the epitaxial rate and T is the epitaxial time.

[0017] Optionally, when the epitaxial stage to be simulated is a single-rate epitaxial process, the initial epitaxial time-rate relationship model of the epitaxial stage to be simulated is fitted according to the epitaxial rate and the epitaxial time in at least one set of epitaxial process parameters, and a reference epitaxial time-rate relationship model corresponding to the epitaxial stage to be simulated is obtained.

[0018] Optionally, when the to-be-simulated epitaxial stage is a step rate epitaxial process, the initial epitaxial time rate relationship model of the first stage is fitted according to the epitaxial rate and the epitaxial time in the at least one set of epitaxial process parameters, to obtain a first reference epitaxial time rate relationship model corresponding to the first stage; the initial epitaxial time rate relationship model of the second stage is fitted according to the epitaxial rate and the epitaxial time in the at least one set of epitaxial process parameters, to obtain a second reference epitaxial time rate relationship model corresponding to the second stage, and the first reference epitaxial time rate relationship model and the second reference epitaxial time rate relationship model jointly constitute a reference epitaxial time rate relationship model corresponding to the to-be-simulated epitaxial stage.

[0019] Optionally, when the to-be-simulated epitaxial stage is a gradual rate epitaxial process, the initial epitaxial time rate relationship model of the to-be-simulated epitaxial stage is fitted according to the epitaxial rate and the epitaxial time in the at least three sets of epitaxial process parameters, to obtain a reference epitaxial time rate relationship model corresponding to the to-be-simulated epitaxial stage.

[0020] Optionally, the method for obtaining the simulated epitaxial filling amount of the to-be-simulated epitaxial process comprises: respectively performing integral processing on the reference epitaxial time rate relationship model corresponding to each to-be-simulated epitaxial stage, to obtain a simulated stage filling amount corresponding to each to-be-simulated epitaxial stage; and adding the simulated stage filling amounts to obtain the simulated epitaxial filling amount of the to-be-simulated epitaxial process.

[0021] Optionally, the method further comprises: performing normalization processing on each epitaxial rate.

[0022] Compared with the prior art, the technical scheme of the embodiment of the present application has the following beneficial effects:

[0023] The simulation method of the epitaxial process provided by the technical scheme of the present application comprises the following steps: obtaining an epitaxial process to be simulated, which comprises a plurality of epitaxial stages to be simulated, each of the epitaxial stages to be simulated having a corresponding initial epitaxial time rate relationship model; then, obtaining a plurality of groups of epitaxial process parameters comprising an epitaxial rate and an epitaxial time, and fitting the initial epitaxial time rate relationship model of any of the epitaxial stages to be simulated according to the epitaxial process parameters to obtain a corresponding reference epitaxial time rate relationship of the epitaxial stage to be simulated; and finally, obtaining a simulation epitaxial filling amount of the epitaxial process to be simulated according to the reference epitaxial time rate relationship models of the plurality of epitaxial stages to be simulated. Since the obtained epitaxial process parameters can correspond to actual epitaxial processes, the initial epitaxial time rate relationship model of any of the epitaxial stages to be simulated is fitted according to the epitaxial process parameters to obtain the reference epitaxial time rate relationship model of the epitaxial stage to be simulated, thereby completing the simulation of the actual epitaxial process. After the simulation epitaxial filling amount of the epitaxial process to be simulated is obtained, the simulation filling amount can simulate the filling condition of the actual epitaxial process, so that the process can be adjusted and a better epitaxial process method can be designed on this basis. Therefore, the simulation method can more targetedly adjust the process and design a better process adjustment method through theoretical calculation, thereby improving the efficiency and cost of actual process adjustment. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a structural schematic diagram of a deep trench filling process;

[0025] Figure 2 is a flowchart of the simulation method of the epitaxial process of an embodiment of the present application;

[0026] Figure 3 is a schematic diagram of an initial epitaxial time rate relationship model corresponding to an epitaxial stage to be simulated in an embodiment of the present application;

[0027] Figure 4 and Figure 5 is a schematic diagram of a process of obtaining an epitaxial rate in an embodiment of the present application;

[0028] Figure 6 is a schematic diagram of a process of obtaining a reference epitaxial time rate relationship model corresponding to each of the epitaxial stages to be simulated in an embodiment of the present application;

[0029] Figure 7 is a schematic diagram of a process of obtaining a reference epitaxial time rate relationship model corresponding to each of the epitaxial stages to be simulated in another embodiment of the present application. DETAILED DESCRIPTION

[0030] As described in the background, in the prior art, in order to find suitable epitaxial filling conditions, the steps of adjusting the epitaxial filling process are complex and inefficient, resulting in a large time cost and high cost of process adjustment.

[0031] Figure 1 is a structural schematic diagram of a deep trench filling process.

[0032] Please refer to Figure 1 The deep trench filling process includes: forming a deep trench (not marked) in the substrate 100; and sequentially growing a first epitaxial layer 101, a second epitaxial layer 102, and a third epitaxial layer 103 in the deep trench until the deep trench is filled. However, in the existing epitaxial growth process for filling the deep trench, the epitaxial filling amount, filling rate, etc. in the deep trench will affect the final filling effect. In order to avoid defects such as holes, gaps, and dislocations, it is usually necessary to repeatedly adjust the process parameters of epitaxial growth, and analyze the filling effect of the epitaxial layer formed under the corresponding process parameters through slicing, so as to adjust the process parameters in the next step accordingly. Therefore, through such a way, it is often necessary to repeat experiments several times to find suitable filling conditions, and the efficiency of process adjustment is low, and the time cost is high.

[0033] To solve the above technical problems, the technical scheme of the present application provides an epitaxial process simulation method, which first acquires an epitaxial process to be simulated including a plurality of epitaxial stages to be simulated, each epitaxial stage to be simulated having a corresponding initial epitaxial time rate relationship model; then, a plurality of groups of epitaxial process parameters including epitaxial rate and epitaxial time are acquired, and the initial epitaxial time rate relationship model of any of the epitaxial stages to be simulated is fitted according to the epitaxial process parameters, to acquire a reference epitaxial time rate relationship corresponding to the epitaxial stage to be simulated; finally, according to the reference epitaxial time rate relationship models corresponding to the plurality of epitaxial stages to be simulated, the simulation epitaxial filling amount of the epitaxial process to be simulated is acquired. Since the acquired epitaxial process parameters can correspond to the actual epitaxial process, the initial epitaxial time rate relationship model of any of the epitaxial stages to be simulated is fitted according to the epitaxial process parameters, to acquire the reference epitaxial time rate relationship model corresponding to the epitaxial stage to be simulated, thereby completing the simulation of the actual epitaxial process. After the simulation epitaxial filling amount of the epitaxial process to be simulated is acquired, the simulation filling amount can simulate the filling condition of the actual epitaxial process, thereby being able to more targetedly adjust the process, and designing a more optimal process adjustment mode through theoretical calculation, thereby improving the efficiency of actual process adjustment and reducing the cost.

[0034] In order to make the above-mentioned purposes, features and benefits of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0035] Figure 2is a flowchart of an embodiment of the simulation method of the epitaxial process.

[0036] Referring to Figure 2 , the simulation method of the epitaxial process comprises:

[0037] Step S11, obtaining an epitaxial process to be simulated, the epitaxial process to be simulated comprising a plurality of epitaxial stages to be simulated, each epitaxial stage to be simulated having a corresponding initial epitaxial time rate relationship model;

[0038] Step S12, obtaining a plurality of groups of epitaxial process parameters, each epitaxial process parameter comprising an epitaxial rate and an epitaxial time;

[0039] Step S13, fitting the epitaxial time rate relationship model of any of the epitaxial stages to be simulated according to the epitaxial rate and the epitaxial time in at least one group of epitaxial process parameters, to obtain a reference epitaxial time rate relationship model corresponding to the epitaxial stage to be simulated;

[0040] Step S14, obtaining a simulation epitaxial filling amount of the epitaxial process to be simulated according to the reference epitaxial time rate relationship models corresponding to the plurality of epitaxial stages to be simulated.

[0041] The following will be described in detail Figures 3 to 6 , each step in the simulation method of the epitaxial process.

[0042] Please refer to Figure 3 Step S11, obtaining an epitaxial process to be simulated, the epitaxial process to be simulated comprising a plurality of epitaxial stages to be simulated, each epitaxial stage to be simulated having a corresponding initial epitaxial time rate relationship model, Figure 3 is a schematic diagram of the initial epitaxial time rate relationship model corresponding to the epitaxial stage to be simulated in this embodiment.

[0043] In this embodiment, the epitaxial stage to be simulated comprises a single rate epitaxial process, a step rate epitaxial process or a gradual rate epitaxial process. The single rate epitaxial process, the step rate epitaxial process or the gradual rate epitaxial process is a deep trench super junction epitaxial filling process method commonly used in actual production.

[0044] Wherein, each of the epitaxial stages to be simulated corresponds to an initial epitaxial time rate relationship model of different types, and the initial epitaxial time rate relationship model corresponding to the single rate epitaxial process, the step rate epitaxial process or the gradual rate epitaxial process is as shown in Figure 3 .

[0045] In the embodiment, when the to-be-simulated epitaxial stage is a single-rate epitaxial process, the epitaxial rate of the to-be-simulated epitaxial stage is constant. Specifically, the initial epitaxial time-rate relationship model is R(T)=d, where R is the epitaxial rate and T is the epitaxial time.

[0046] In the embodiment, when the to-be-simulated epitaxial stage is a step-rate epitaxial process, the to-be-simulated epitaxial stage includes a first stage and a second stage, the epitaxial rate of the first stage is constant, the epitaxial rate of the second stage is constant, and the epitaxial rate of the first stage is greater than the epitaxial rate of the second stage.

[0047] Specifically, the first stage has a corresponding initial first epitaxial time-rate relationship model R(T)=e(T0≤T<T1), and the second stage has a corresponding initial second epitaxial time-rate relationship model R(T)=f(T1≤T<T2), where R is the epitaxial rate and T is the epitaxial time. Therefore, the epitaxial rate of the to-be-simulated epitaxial stage jumps at T1.

[0048] In the embodiment, when the to-be-simulated epitaxial stage is a step-rate epitaxial process, the epitaxial rate of the to-be-simulated epitaxial stage is constant. Specifically, the initial epitaxial time-rate relationship model is R(T)=d, where R is the epitaxial rate and T is the epitaxial time. 2 Therefore, the epitaxial rate of the to-be-simulated epitaxial stage gradually decreases as the epitaxial time increases.

[0049] In another embodiment, when the to-be-simulated epitaxial stage is a step-rate epitaxial process, the epitaxial rate of the to-be-simulated epitaxial stage increases as the epitaxial time increases.

[0050] Please refer to 4 and Figure 5 Referring to step S12, a plurality of sets of epitaxial process parameters are obtained, each epitaxial process parameter including an epitaxial rate and an epitaxial time. Wherein, Figure 4 and Figure 5 is a schematic diagram of the process of obtaining the epitaxial rate in the embodiment.

[0051] In the embodiment, the method for obtaining the epitaxial rate in the plurality of sets of epitaxial process parameters includes: providing a substrate 200; performing a plurality of preliminary epitaxial processes on the substrate 200, each preliminary epitaxial process having a corresponding epitaxial process parameter; obtaining the performing time t and the epitaxial thickness h of each preliminary epitaxial process; and obtaining each epitaxial rate v=h / t according to the performing time t and the epitaxial thickness h.

[0052] In the embodiment, the surface of the substrate 200 is planar. Each of the preparatory epitaxial processes performed on the substrate 200 is performed under a corresponding epitaxial process parameter, and each epitaxial process parameter is different, so that each of the preparatory epitaxial processes has a different epitaxial rate, i.e., each of the obtained epitaxial rates can be achieved by the actual epitaxial process parameter.

[0053] In the embodiment, the epitaxial time in each of the epitaxial process parameters is set according to the corresponding process design requirement.

[0054] In the subsequent simulation of the epitaxial process, each epitaxial rate is combined with a corresponding epitaxial time to form an epitaxial process parameter, and then the reference epitaxial time rate relationship model corresponding to the to-be-simulated epitaxial stage is obtained in combination with the initial epitaxial time rate relationship model possessed by each to-be-simulated epitaxial stage.

[0055] In the embodiment, the more the data amount of different epitaxial rates obtained, and the more the data amount of different epitaxial process parameters formed, the more abundant the simulation of the epitaxial process can be, and the more flexible and accurate the reference epitaxial time rate relationship model obtained.

[0056] In the embodiment, 6 preparatory epitaxial processes are performed on the substrate, each of the preparatory epitaxial processes has different epitaxial process parameters, so as to obtain 6 different epitaxial rates. The epitaxial thickness of each preparatory epitaxial process is the thickness of each epitaxial layer formed correspondingly, and the time of each preparatory epitaxial process is the formation time of each epitaxial layer correspondingly. Among them, the epitaxial thickness of each preparatory epitaxial process is the same.

[0057] In other embodiments, the epitaxial thickness of each preparatory epitaxial process can be different. In addition, the number of preparatory epitaxial processes can be less than or greater than 6, and on this basis, in order to ensure that there is enough data amount of epitaxial rate, the number of epitaxial rates should be greater than or equal to 4.

[0058] Please continue to refer to Figure 4 and Figure 5 In the embodiment, by sequentially performing each of the preparatory epitaxial processes on the substrate 200, different epitaxial layers are obtained, so as to obtain corresponding epitaxial rates. Each of the preparatory epitaxial processes can be denoted as preparatory epitaxial process 1, preparatory epitaxial process 2, preparatory epitaxial process 3, preparatory epitaxial process 4, preparatory epitaxial process 5, and preparatory epitaxial process 6, and correspondingly, the formed epitaxial layers are denoted as first epitaxial layer 201, second epitaxial layer 202, third epitaxial layer 203, fourth epitaxial layer 204, fifth epitaxial layer 205, and sixth epitaxial layer 206.

[0059] In other embodiments, each of the preparatory epitaxial processes can be performed on different substrates, so as to obtain corresponding epitaxial rates.

[0060] In the embodiment, after the epitaxial rate is obtained, each epitaxial rate is normalized, facilitating subsequent model fitting.

[0061] Please combine Figure 6 Referring to step S13, Figure 6 A schematic diagram for obtaining a reference epitaxial time rate relationship model corresponding to each to-be-simulated epitaxial stage in the embodiment. An initial epitaxial time rate relationship model of any to-be-simulated epitaxial stage is fitted according to the epitaxial rate and the epitaxial time in at least one set of epitaxial process parameters, to obtain a reference epitaxial time rate relationship model corresponding to the to-be-simulated epitaxial stage.

[0062] In the embodiment, by selecting several sets of epitaxial process parameters and combining the corresponding type of to-be-simulated epitaxial stage, an initial epitaxial time rate relationship model of the to-be-simulated epitaxial stage is fitted according to the epitaxial rate and the epitaxial time in several epitaxial process parameters, to obtain a reference epitaxial time rate relationship model corresponding to each to-be-simulated epitaxial stage. The combination of each reference epitaxial time rate relationship model constitutes the overall reference model of the to-be-simulated epitaxial process, and the simulation of the actual epitaxial process is completed.

[0063] Specifically, in the embodiment, the to-be-simulated epitaxial process includes a first to-be-simulated epitaxial stage A and a second to-be-simulated epitaxial stage B. The first to-be-simulated epitaxial stage A is a gradual rate epitaxial process, and the corresponding epitaxial time rate relationship model is R(T)=a*T 2 +b*T+c; the second to-be-simulated epitaxial stage B is a single rate epitaxial process, and the corresponding initial epitaxial time rate relationship model is R(T)=d, where R is the epitaxial rate and T is the epitaxial time.

[0064] The specific method for obtaining a reference epitaxial time rate relationship model corresponding to each to-be-simulated epitaxial stage is as follows. Taking obtaining a reference epitaxial time rate relationship model corresponding to the first to-be-simulated epitaxial stage A as an example, three sets of epitaxial process parameters are selected to cooperate with the first to-be-simulated epitaxial stage A, where the epitaxial rates in the three sets of epitaxial process parameters are Figure 5 as shown in the epitaxial rates of the preliminary epitaxial process 1, the preliminary epitaxial process 2 and the preliminary epitaxial process 3, and the corresponding epitaxial times in the three sets of epitaxial process parameters are set values. Then, the initial epitaxial time rate relationship model of the first to-be-simulated epitaxial stage A is fitted according to the three sets of epitaxial process parameters, to obtain the actual values A1, B1 and C1 of the coefficients a, b and c in the epitaxial time rate relationship model R(T)=a*T 2 +b*T+c, thereby obtaining the reference epitaxial time rate relationship model R(T)=A1*T 2 +B1*T+C1.

[0065] Similarly, by selecting two sets of epitaxial process parameters for the second to-be-simulated epitaxial stage B, wherein the epitaxial rates in the two sets of epitaxial process parameters are respectively Figure 5 the epitaxial rate of the preliminary epitaxial process 4 shown in the figure, the corresponding epitaxial time in the two sets of epitaxial process parameters is a set value. Then, the initial epitaxial time rate relationship model of the second to-be-simulated epitaxial stage B is fitted according to the two sets of epitaxial process parameters, and the actual value D1 of the coefficient d in the epitaxial time rate relationship model R(T) = d is obtained, thereby obtaining the reference epitaxial time rate relationship model R(T) = D1. The combination of the reference epitaxial time rate relationship models corresponding to the first to-be-simulated epitaxial stage A and the second to-be-simulated epitaxial stage B constitutes the overall reference model of the to-be-simulated epitaxial process, denoted as reference model one.

[0066] In this embodiment, the starting point and the ending point of each to-be-simulated epitaxial stage are determined by epitaxial process parameters, and each epitaxial process parameter and the initial epitaxial time rate relationship model can correspond to an actual epitaxial process method. Therefore, the to-be-simulated epitaxial stage and the corresponding epitaxial process parameters selected in this simulation method can be specifically implemented by an actual epitaxial process, that is, each reference epitaxial time rate relationship model corresponds to an actual epitaxial process method, thereby making the simulation method of the epitaxial process in this embodiment have practical value.

[0067] Next, please continue to combine Figure 6 According to the reference epitaxial time rate relationship models corresponding to the to-be-simulated epitaxial stages, the simulated epitaxial filling amount of the to-be-simulated epitaxial process is obtained.

[0068] In this embodiment, the method for obtaining the simulated epitaxial filling amount of the to-be-simulated epitaxial process includes: respectively integrating the reference epitaxial time rate relationship models corresponding to each to-be-simulated epitaxial stage to obtain the simulated stage filling amount corresponding to each to-be-simulated epitaxial stage; and adding the simulated stage filling amounts to obtain the simulated epitaxial filling amount of the to-be-simulated epitaxial process.

[0069] Specifically, the reference epitaxial time rate relationship model R(T) = A1*T 2 + B1*T + C1 corresponding to the first to-be-simulated epitaxial stage A, therefore, the simulated stage filling amount corresponding to the first to-be-simulated epitaxial stage A is The reference epitaxial time rate relationship model R(T) = D1 corresponding to the second to-be-simulated epitaxial stage B, therefore, the simulated stage filling amount corresponding to the second to-be-simulated epitaxial stage B is Wherein, T 1P is the ending point of the first to-be-simulated epitaxial stage A, and T 1E is the ending point of the second to-be-simulated epitaxial stage B. Therefore, the simulated epitaxial filling amount Kf1 = K1 + K2.

[0070] In the embodiment, since each reference epitaxial time rate relationship model corresponds to an actual epitaxial process method, the simulation filling amount obtained by respectively integrating the reference epitaxial time rate relationship models can simulate the filling condition of the actual epitaxial process, which can guide the subsequent epitaxial process adjustment direction. By adjusting the epitaxial process on this basis, a better epitaxial process method can be designed and verified by the actual epitaxial process. Therefore, the epitaxial process simulation method can more targetedly adjust the process, and a better process adjustment scheme can be designed by theoretical calculation, thereby improving the efficiency of the actual process adjustment and reducing the cost.

[0071] Please refer to Figure 6 on the basis of Figure 7 , Figure 7 is a schematic diagram for obtaining the reference epitaxial time rate relationship model corresponding to each to-be-simulated epitaxial stage in another embodiment of the application.

[0072] In the embodiment, different to-be-simulated epitaxial processes and corresponding simulation epitaxial filling amounts can be obtained multiple times, so that the epitaxial process simulation method has more flexibility and richness.

[0073] Figure 7 Three different overall reference models corresponding to three different to-be-simulated epitaxial processes are respectively shown, which are respectively referred to as reference model one, reference model two and reference model three.

[0074] The selection of each to-be-simulated epitaxial stage, each epitaxial process parameter and the obtaining method of the simulation epitaxial filling amount corresponding to the reference model one are the same as those of the reference model one shown in Figure 6 , which will not be described herein again.

[0075] In the embodiment, the to-be-simulated epitaxial process corresponding to the reference model two includes two to-be-simulated epitaxial stages, which are respectively a gradual rate epitaxial process and a single rate epitaxial process; by selecting a plurality of groups of epitaxial process parameters, the initial epitaxial time rate relationship model of each to-be-simulated epitaxial stage is fitted to obtain the reference epitaxial time rate relationship model corresponding to each to-be-simulated epitaxial stage; then, the reference epitaxial time rate relationship models corresponding to the plurality of to-be-simulated epitaxial stages are integrated to obtain the simulation stage filling amount corresponding to each to-be-simulated epitaxial stage, and the simulation epitaxial filling amount of the to-be-simulated epitaxial process is obtained by summation.

[0076] In the embodiment, the to-be-simulated epitaxial process corresponding to the reference model three includes one to-be-simulated epitaxial stage, which is a step-rate epitaxial process including a first stage and a second stage, the epitaxial rate of the first stage is constant, the epitaxial rate of the second stage is constant, and the epitaxial rate of the first stage is greater than that of the second stage. By selecting a plurality of sets of epitaxial process parameters, an initial first epitaxial time rate relationship model corresponding to the first stage and an initial second epitaxial time rate relationship model corresponding to the second stage are fitted to obtain a corresponding reference epitaxial time rate relationship model; then, the reference epitaxial time rate relationship model is integrated to obtain a simulated epitaxial filling amount of the to-be-simulated epitaxial process.

[0077] In the embodiment, the method for obtaining the reference epitaxial time rate relationship model corresponding to each to-be-simulated epitaxial stage is specifically as follows.

[0078] When the to-be-simulated epitaxial stage is a single-rate epitaxial process, an initial epitaxial time rate relationship model of the to-be-simulated epitaxial stage is fitted according to the epitaxial rate and the epitaxial time in at least one set of epitaxial process parameters to obtain a reference epitaxial time rate relationship model corresponding to the to-be-simulated epitaxial stage.

[0079] When the to-be-simulated epitaxial stage is a step-rate epitaxial process, an initial first epitaxial time rate relationship model of the first stage is fitted according to the epitaxial rate and the epitaxial time in at least one set of epitaxial process parameters to obtain a first reference epitaxial time rate relationship model corresponding to the first stage; an initial second epitaxial time rate relationship model of the second stage is fitted according to the epitaxial rate and the epitaxial time in at least one set of epitaxial process parameters to obtain a second reference epitaxial time rate relationship model corresponding to the second stage, and the first reference epitaxial time rate relationship model and the second reference epitaxial time rate relationship model jointly constitute a reference epitaxial time rate relationship model corresponding to the to-be-simulated epitaxial stage.

[0080] When the to-be-simulated epitaxial stage is a gradual-rate epitaxial process, an initial epitaxial time rate relationship model of the to-be-simulated epitaxial stage is fitted according to the epitaxial rate and the epitaxial time in at least three sets of epitaxial process parameters to obtain a reference epitaxial time rate relationship model corresponding to the to-be-simulated epitaxial stage.

[0081] In the embodiment, the epitaxial process parameters used for fitting the initial epitaxial time rate relationship model of each to-be-simulated epitaxial stage can all correspond to actual epitaxial processes, and the epitaxial rate in each epitaxial process parameter is selected from the epitaxial rates in each of the preliminary epitaxial processes shown in the table. Figure 5 Therefore, the reference model one, the reference model two, and the reference model three can all correspond to actual epitaxial processes.

[0082] In the embodiment, the start point and the end point of each to-be-simulated epitaxial stage are determined by epitaxial process parameters.

[0083] In the embodiment, the simulated epitaxial filling amounts corresponding to the reference model one, the reference model two and the reference model three are respectively denoted as a first simulated epitaxial filling amount K f1 , a second simulated epitaxial filling amount K f2 and a third simulated epitaxial filling amount K f3 . In the embodiment, through theoretical calculation, the first simulated epitaxial filling amount K f1 is 67714, the second simulated epitaxial filling amount K f2 is 67447, and the third simulated epitaxial filling amount K f3 is 67265, and the values of the three are close. Then, the epitaxial processes corresponding to the reference model one, the reference model two and the reference model three are realized through actual operation, and the deep trench epitaxial filling amounts obtained under the three epitaxial processes are also close. Therefore, it is confirmed that the simulation method of the epitaxial process can effectively simulate the epitaxial filling condition in the actual deep trench filling epitaxial process.

[0084] In actual production process, the corresponding reference epitaxial time rate relationship model and simulated epitaxial filling amount can be obtained through the simulation method of the epitaxial process, so as to guide the adjustment and design direction of the epitaxial process. Specifically, when the actual epitaxial filling amount obtained through the actual epitaxial process corresponding to the reference epitaxial time rate relationship model is too small, the to-be-simulated epitaxial stages in the to-be-simulated epitaxial process can be adjusted, and different epitaxial process parameters can be selected to simulate the initial epitaxial time rate relationship model, so as to obtain a new reference epitaxial time rate relationship model, so as to obtain a higher simulated epitaxial filling amount, and then verified through actual epitaxial process. Similarly, when the actual epitaxial filling amount obtained through the actual epitaxial process corresponding to the reference epitaxial time rate relationship model is too large, the to-be-simulated epitaxial process can also be adjusted through the similar method, so as to obtain a lower simulated epitaxial filling amount. In addition, the simulated epitaxial filling amount to be reached can also be preset, and the to-be-simulated epitaxial process is adjusted according to the simulated epitaxial filling amount to be reached, so as to obtain a suitable reference epitaxial time rate relationship model, and thus obtain an actual epitaxial process.

[0085] Therefore, the simulation method of the epitaxial process can simulate the filling amount, filling quality and the like of the actual epitaxial process, on the basis of which the process is adjusted, a better epitaxial process method can be designed, and is verified through the actual epitaxial process. Therefore, through the simulation method of the epitaxial process, the process can be more targeted adjusted, a better process adjustment method is designed through theoretical calculation, the process of repeated experiments and structure slice observation is avoided, and therefore the efficiency of the deep trench epitaxial filling process adjustment in actual production is improved, and the cost is greatly reduced.

[0086] Although the present application is disclosed as above, the present application is not limited to this. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore the protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. A method for simulating epitaxial processes, characterized in that, include: Obtain the epitaxial process to be simulated, which includes several epitaxial stages to be simulated, and each epitaxial stage to be simulated has a corresponding initial epitaxial time rate relationship model. Acquire several sets of epitaxial process parameters, each of which includes epitaxial rate and epitaxial time; The initial epitaxial time-rate relationship model of any of the epitaxial stages to be simulated is fitted according to the epitaxial rate and epitaxial time in at least one set of epitaxial process parameters to obtain the reference epitaxial time-rate relationship model corresponding to the epitaxial stage to be simulated. Based on the reference epitaxial time rate relationship model corresponding to the several epitaxial stages to be simulated, the simulated epitaxial filling amount of the epitaxial process to be simulated is obtained.

2. The method for simulating epitaxial processes as described in claim 1, characterized in that, A method for obtaining the epitaxial rate from several sets of epitaxial process parameters includes: providing a substrate; performing several pre-epitaxial processes on the substrate, each pre-epitaxial process having corresponding epitaxial process parameters; obtaining the execution time t and epitaxial thickness h of each pre-epitaxial process; and obtaining the epitaxial rate v = h / t based on the execution time t and epitaxial thickness h.

3. The method for simulating epitaxial processes as described in claim 2, characterized in that, The substrate surface is planar.

4. The method for simulating epitaxial processes as described in claim 1, characterized in that, The number of epitaxial rates obtained is greater than or equal to 4.

5. The method for simulating epitaxial processes as described in claim 1, characterized in that, The epitaxial stage to be simulated includes single-rate epitaxial process, stepped-rate epitaxial process, or gradual-rate epitaxial process.

6. The method for simulating epitaxial processes as described in claim 5, characterized in that, When the epitaxial stage to be simulated is a single-rate epitaxial process, the epitaxial rate of the epitaxial stage to be simulated is constant.

7. The method for simulating epitaxial processes as described in claim 6, characterized in that, When the epitaxial stage to be simulated is a single-rate epitaxial process, the initial epitaxial time-rate relationship model is R(T)=d, where R is the epitaxial rate, T is the epitaxial time, and d is a coefficient.

8. The method for simulating epitaxial processes as described in claim 5, characterized in that, When the epitaxial stage to be simulated is a stepped rate epitaxial process, the epitaxial stage to be simulated includes a first stage and a second stage. The epitaxial rate of the first stage is constant, the epitaxial rate of the second stage is constant, and the epitaxial rate of the first stage is greater than the epitaxial rate of the second stage.

9. The method for simulating epitaxial processes as described in claim 8, characterized in that, The first stage has an initial first extensional time rate relationship model of R(T)=e (T0≤T<T1); the second stage has an initial second extensional time rate relationship model of R(T)=f (T1≤T<T2), where R is the extensional rate, T is the extensional time, the time period from T0 to T1 is the first stage, the time period from T1 to T2 is the second stage, and e and f are both coefficients.

10. The method for simulating epitaxial processes as described in claim 5, characterized in that, When the epitaxial stage to be simulated is a gradual rate epitaxial process, the epitaxial rate of the epitaxial stage to be simulated increases or decreases as the epitaxial time increases.

11. The method for simulating epitaxial processes as described in claim 10, characterized in that, When the epitaxial stage to be simulated is a gradual rate epitaxial process, the initial epitaxial time-rate relationship model is R(T)=a*T. 2 +b*T+c, where R is the extension rate, T is the extension time, and a, b, and c are coefficients.

12. The method for simulating epitaxial processes as described in claim 6, characterized in that, When the epitaxial stage to be simulated is a single-rate epitaxial process, the initial epitaxial time-rate relationship model of the epitaxial stage to be simulated is fitted according to the epitaxial rate and epitaxial time in at least one set of epitaxial process parameters to obtain the reference epitaxial time-rate relationship model corresponding to the epitaxial stage to be simulated.

13. The method for simulating epitaxial processes as described in claim 8, characterized in that, When the epitaxial stage to be simulated is a stepped-rate epitaxial process, the initial epitaxial time-rate relationship model of the first stage is fitted according to the epitaxial rate and epitaxial time in at least one set of epitaxial process parameters to obtain a first reference epitaxial time-rate relationship model corresponding to the first stage; the initial epitaxial time-rate relationship model of the second stage is fitted according to the epitaxial rate and epitaxial time in at least one set of epitaxial process parameters to obtain a second reference epitaxial time-rate relationship model corresponding to the second stage. The first reference epitaxial time-rate relationship model and the second reference epitaxial time-rate relationship model together constitute the reference epitaxial time-rate relationship model corresponding to the epitaxial stage to be simulated.

14. The method for simulating epitaxial processes as described in claim 10, characterized in that, When the epitaxial stage to be simulated is a gradual rate epitaxial process, the initial epitaxial time-rate relationship model of the epitaxial stage to be simulated is fitted according to the epitaxial rate and epitaxial time in at least three sets of epitaxial process parameters to obtain the reference epitaxial time-rate relationship model corresponding to the epitaxial stage to be simulated.

15. The method for simulating epitaxial processes as described in claim 1, characterized in that, The method for obtaining the simulated epitaxial fill amount of the epitaxial process to be simulated includes: performing integration processing on the reference epitaxial time rate relationship model corresponding to each of the epitaxial stages to be simulated, and obtaining the simulated stage fill amount corresponding to each of the epitaxial stages to be simulated; and adding the fill amounts of each simulated stage to obtain the simulated epitaxial fill amount of the epitaxial process to be simulated.

16. The method for simulating epitaxial processes as described in claim 2, characterized in that, Also includes: The extrapolation rates are normalized.

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