CN113189967A - Control performance diagnosis method for semiconductor process batch control system - Google Patents
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Abstract
The invention provides a control performance diagnosis method of a semiconductor process batch control system, which comprises the following steps of firstly, estimating reference working condition white noise, a reference working condition disturbance model, reference working condition model residual error, actual working condition white noise, an actual working condition disturbance model and actual working condition model residual error according to closed loop data of historical normal working conditions and closed loop data of actual working conditions; secondly, acquiring four diagnostic monitoring quantities according to the reference working condition white noise and the model residual thereof, the actual working condition white noise and the model residual thereof, and acquiring the control performance monitoring quantity and the control upper limit/lower limit of the four diagnostic monitoring quantities according to the closed loop data of the historical normal working condition; and finally, evaluating the control performance of the batch control system according to the control performance monitoring quantity and the control upper limit/lower limit thereof. The method not only can correctly evaluate the control performance of the closed-loop system under the conventional operating condition of the semiconductor manufacturing process, but also can effectively diagnose the reason causing the performance reduction of the system, thereby reducing the cost of system maintenance and improving the safety of the system.
Description
Technical Field
The invention belongs to the field of control performance evaluation and diagnosis of a process industrial control system, and particularly relates to a control performance diagnosis method of a semiconductor manufacturing process batch control system, which is used for evaluating the control performance of the semiconductor manufacturing process batch control system and diagnosing the reason of the degradation of the control performance.
Background
In recent years, with the adoption of a great market demand, abundant manpower resources and other advantages, the semiconductor industry in China has rapidly developed and has become the focus of attention of the global integrated circuit industry. The industrial level of semiconductors in China is still extremely disproportionate to the status of the big country in China. For example, high-tech enterprises in the middle and high-tech village take the majority of computer market share in China, but the profit margin is only about 3%, while the pure profit margin of the central processor manufacturer intel for years is more than 30%.
The semiconductor industry is primarily concerned with the industry of manufacturing semiconductor solid state devices and circuits, a process known as wafer fabrication. The production of wafers is a rather long and complex process involving hundreds of process steps, which cannot be performed perfectly at each time, and the occurrence of defects in any one process affects the final quality of the product. An Exponentially Weighted Moving Average (EWMA) batch-to-batch controller is an advanced controller commonly used in semiconductor manufacturing processes, and the controller adjusts manipulated variables of the next batch according to input and output data of historical batches, so that influences of process disturbances in forms of offset, drift and the like on product quality are reduced, and yield is improved. Wafer processing is often affected by internal and external uncertainties of the system, which may cause degradation of system control performance, reduction of energy, material utilization, and economic benefits, and even safety hazards. Therefore, it is important to research the performance monitoring and diagnosis technology of the EWMA batch control system in the semiconductor manufacturing process to improve the quality of the wafer product.
After the system is put into operation, the control quality of the EWMA batch controller is influenced by factors such as model mismatch, external disturbance change, controller adjustment and the like, and the system performance is reduced due to the factors. The product quality, operational safety, material energy consumption rate and economic performance of semiconductor manufacturing processes are closely related to the control performance of batch controllers. The loss of control performance from any one process can be quite dramatic, with losses of up to $ 5000 for 300 mm wafers.
Disclosure of Invention
The invention provides a control performance diagnosis method of a semiconductor manufacturing process batch control system, which aims to monitor the control performance of an EWMA batch controller and diagnose the reason of performance degradation, and solves the technical problem that the existing control performance monitoring method is difficult to determine the specific factors of control performance degradation.
The technical scheme of the invention is realized as follows:
a control performance diagnostic method for a semiconductor process batch control system comprises the following steps:
s1, obtaining N groups of input data and output data of historical normal working conditions of the EWMA batch control system in the semiconductor manufacturing process as sample data, dividing the sample data into S +1 windows, and calculating a white noise estimation value epsilon of the reference working condition by using the input data and the output data of the first windowrAnd reference working condition disturbance model estimation valueObtaining process-disturbance combined model residual e (t), process data setAnd output data set Y1 0And based on the process data setObtaining a matrix X of reference conditions1From the output data set Y1 0Obtaining a matrix Y of reference conditions1Construction of Hankel matrix XpAnd XfAnd projection matrix Jq;
S2, constructing a process data set using the input data and the output data of the k' th windowAnd outputting the data setFrom a process data setObtaining matrix X of actual working conditionk'From the output data setObtaining matrix Y of actual working conditionsk'Obtaining the control performance monitoring quantity of the EWMA batch-to-batch control system corresponding to the kth window by adopting a typical variable analysis methodWherein k ═ 2,3, …, S + 1;
s3, according to the reference working condition disturbance model estimated value in the step S1Obtaining reference working condition model residual error v from input data and output data of kth windowr,k'(t) and model mismatch/perturbation dynamics joint monitoring volume
S4, input data using k' th windowObtaining the white noise estimation value epsilon of the actual working condition corresponding to the kth window by the output datah,k'(t) and actual condition disturbance model estimation valueAnd according to the actual working condition disturbance model estimated valueObtaining the residual error v of the actual working condition modelh,k'(t);
S5, according to the reference working condition white noise estimated value epsilon in the step S1rAnd the white noise estimate of the actual condition ε in step S4h,k'(t) calculating an interference characteristic monitoring quantityAccording to the reference working condition model residual v in the step S3r,k'(t) and the actual condition model residual v in step S4h,k'(t) calculating the amount of monitoring of the disturbance modelAccording to the actual working condition white noise estimated value epsilon in the step S4h,k'(t) and the actual condition model residual vh,k'(t) obtaining a model mismatch monitoring quantity
S6, respectively obtaining the control upper limit UP of the control performance monitoring quantity by adopting a kernel density estimation methodCPIUpper control limit UP of model mismatch/disturbance dynamic joint monitoring quantityPDMIUpper limit UP of control of the monitored quantity of interference characteristicsDVILower limit of control LP of disturbance characteristic monitoring amountDVILower control limit LP of disturbance model monitoring quantityDMIAnd the upper control limit UP of the model mismatch monitoring quantityPMI;
S7, collecting N1 groups of input data and output data of the EWMA batch control system of the semiconductor process on line, and obtaining the control performance monitoring quantity eta of the current working conditionCPIAccording to the upper limit of control in step S6UPCPIJudging whether the control performance of the closed-loop system is reduced or not in real time;
s8, if the control performance monitoring quantity etaCPIControl upper limit UP greater than control performance monitoring amountCPIIf the performance of the EWMA batch control system is reduced, executing the step S9, otherwise, the EWMA batch control system has good performance;
s9, using the reference working condition disturbance model estimated value in the step S1Obtaining the model mismatch/disturbance dynamic combined monitoring quantity eta of the current working condition from the N1 groups of input data and output data in the step S7PDMI;
S10, if the model mismatching/disturbance dynamic joint monitoring quantity etaPDMIGreater than the upper control limit UP of the combined monitoring quantity of model mismatch/disturbance dynamics in step S6PDMIIf the performance of the EWMA batch control system is reduced due to model mismatch or disturbance dynamics, executing the step S11, otherwise, the performance of the EWMA batch control system is reduced due to the change of the controller parameters;
s11, calculating the disturbance characteristic monitoring quantity eta of the current working conditionDVIMonitoring quantity eta of disturbance modelDMIAnd model mismatch monitor ηPMI(ii) a Disturbance characteristic monitoring quantity eta when current working conditionDVIGreater than the upper control limit UP of the disturbance characteristic monitoring amount in step S6DVIOr less than the lower control limit LP of the disturbance characteristic monitored quantityDVIWhen the interference characteristic changes, the performance of the EWMA batch control system is reduced; when the disturbance model monitors the quantity etaDMILower control limit LP less than disturbance model monitoring quantityDMIMeanwhile, the performance of the EWMA batch control system is reduced due to the change of the disturbance model; when model mismatch monitor ηPMIControl upper limit UP greater than model mismatch monitoring amountPMIModel mismatch results in performance degradation of the EWMA batch-to-batch control system.
Matrix X of the reference condition1And Y1Respectively expressed as:
wherein u isiRepresents the ith process input vector, i 1, …, mu,muDenotes the number of input vectors, t denotes the sampling time, ui"represents the i-th process input vector after normalization, i.e. Means representing the ith process input vector, (σ)u,r)iRepresents the standard deviation of the ith process input vector; y isjRepresents the jth process output vector, j ═ 1, …, my,myIndicating the number of output vectors, yj"represents the normalized j-th process output vector, i.e. Means for representing the jth process output vector, (σ)y,r)jRepresents the standard deviation of the jth process output vector; e.g. of the typej(t) denotes the jth process-perturbation joint model residual vector, where ej=(ej(t)), ej(t)=yj(t)-(Gm(q-1))ju(t),(Gm(q-1))jRepresenting the process model G used in the first windowm(q-1) J-th line of (1), yj(t) denotes the jth process output at the tth sampling instant, u (t) denotes the column vector formed by all process inputs at the tth sampling instant in the first window, e ″jRepresents the normalized j process-perturbation joint model residual vector, means for representing the jth process-perturbation combined model residual, (σ)e,r)jRepresenting the standard deviation of the jth process-perturbation combined model residual error;
the projection matrix JqComprises the following steps:wherein, VqRepresenting a matrix constructed from the first q columns of the unitary matrix V,represents the Hankel matrix XpThe covariance matrix of (2).
wherein the content of the first and second substances,the process input vector representing the kth window,the process-perturbation joint model residual vector representing the kth window,a process output vector representing the kth window;
matrix X of the actual working conditionk'And Yk'Respectively expressed as:
wherein u isi,k'The process input vector, u ", representing the k' th windowi,k'The process input vector representing the normalized k' th window, i.e.yj,k'Represents the process output vector, y ″, of the k' th windowj,k'The process output vector representing the normalized k' th window, i.e.ej,k'Process-perturbation joint model residual vector representing the kth window, ej,k'=(ej,k'(t)), ej,k'(t)=yj,k'(t)-(Gm,k′(q-1))juk'(t),yj,k'(t) denotes the jth process output, u, at the tth sampling instant in the kth windowk'(t) represents the column vector formed by all process inputs at the tth sampling instant in the kth window, (G)m,k′(q-1))jRepresenting the Process model G used by the EWMA batch-to-batch controller in the k' th windowm,k′(q-1) Line j, e ″)j,k'Process-perturbation joint model residuals representing the normalized k' th window, i.e.
Obtaining control performance monitoring quantity of EWMA batch control system by adopting typical variable analysis methodComprises the following steps:wherein the content of the first and second substances,indicating correspondence of the kth windowAmount of control Performance monitoring of EWMA inter-batch control System, JqRepresenting a projection matrix, pk,k'Representing matrix Xp,k'The k-th column of (1).
The model mismatch/disturbance dynamic joint monitoring quantityComprises the following steps:wherein the content of the first and second substances,represents the model mismatch/disturbance dynamic joint monitoring quantity corresponding to the k' th window,has a value range of (0, 1)],εr(t) the white noise estimation value of the reference condition at the t-th sampling moment, vr,k'(t) represents the reference condition model residual at the t-th sampling instant in the kth' window, | cov (εr(t)) | denotes εrDeterminant of covariance matrix of (t), | cov (v)r,k'(t)) | denotes vr,k'(t) determinant of covariance matrix;
the reference working condition model residual vr,k'(t) is:wherein v isr,k'(t) represents the reference condition model residual error corresponding to the k' th window,disturbance model estimation value representing reference working conditionInverse of (y)k'(t) represents the process output vector at the t-th sampling instant of the k' -th window, uk'(t) represents the process input vector at the t-th sampling instant in the k' -th window, Gm,k′(q-1) Denotes the k' th windowA process model for use with a intraoral EWMA batch controller.
The actual working condition model residual error vh,k'(t) is:wherein v ish,k'(t) represents the real model residual at the t-th sampling instant of the k' -th window,actual condition disturbance model estimated value representing k' th windowInverse of (y)k'(t) represents the process output vector at the t-th sampling instant of the k' -th window, uk'(t) represents the process input vector at the t-th sampling instant of the k' -th window, Gm,k′(q-1) Representing the process model used by the EWMA batch controller in the k' th window.
Step S5 includes the following steps:
s5.1, calculating interference characteristic monitoring quantityWherein epsilonr(t) represents the white noise estimation value of the reference condition at the t-th sampling moment, epsilonh,k'(t) represents the white noise estimate for the actual condition at the t-th sampling instant in the kth' window, | cov (εh,k'(t)) | denotes εh,k'Determinant of covariance matrix of (t), | cov (εr(t)) | denotes εr(t) determinant of covariance matrix;
s5.2, calculating the monitoring quantity of the disturbance modelWherein the content of the first and second substances,represents the perturbation model monitoring quantity of the k' th window,has a value range of (0, 1)]If, ifNear or equal to 1, the perturbation model is unchanged, vr,k'(t) represents the reference operating condition model residual at the t-th sampling moment in the k' -th window, vh,k'(t) represents the actual condition model residual at the t-th sampling instant in the k' -th window, J (f (v)r,k'(t)),g(vh,k'(t))) represents vh,k'(t) and vr,k'(t) KL divergence, expressed as:
wherein, f (v)r,k'(t)) represents v constructed using the nuclear density estimation methodr,k'(t) probability density function, f (v)h,k'(t)) represents v obtained by the nuclear density estimation methodh,k'(t) probability density function, i ═ 1,2, …, Nf,NfRepresenting the total number of independent identically distributed sample points resulting from the kernel density estimation;
s5.3, calculating model mismatch monitoring quantityWherein epsilonh,k'(t) represents the white noise estimation value of the actual working condition at the t sampling moment in the k' th window, vh,k'(t) represents the real-world model residual at the t-th sampling instant in the kth' window, | cov (εh,k'(t)) | denotes εh,k'Determinant of covariance matrix of (t), | cov (v)h,k'(t)) | denotes vh,k'(t) determinant of covariance matrix.
Step S6 includes the following steps:
s6.1, calculating the control upper limit UP of the control performance monitoring quantityCPI:Wherein the content of the first and second substances,the control performance monitoring quantity corresponding to the kth window is K ', K' is 2, 3.., S +1, h represents the kernel bandwidth, and K (·) represents the kernel density estimation with the kernel as a radial basis function;
s6.2, calculating the control upper limit UP of the model mismatch/disturbance dynamic combined monitoring quantityPDMI: Wherein the content of the first and second substances,model mismatch/disturbance dynamic combined monitoring quantity corresponding to the kth' window;
s6.3, calculating the control upper limit UP of the interference characteristic monitoring quantityDVIAnd a lower control limit LPDVI:Wherein the content of the first and second substances,is the interference characteristic monitoring quantity corresponding to the kth window;
s6.4, calculating a control lower limit LP of the monitoring quantity of the disturbance modelDMI:Wherein the content of the first and second substances,is the disturbance model monitoring quantity corresponding to the kth window;
s6.5, calculating the control upper limit UP of the model mismatch monitoring quantityPMI:Wherein the content of the first and second substances,is the interference corresponding to the k' th windowFeature monitoring amount.
Step S7 includes the following steps:
s7.1, collecting N1 groups of input data and output data of the EWMA batch control system of the semiconductor process on line as actual working condition sample data, and dividing the actual working condition sample data into S1An online window, each window containing n groups of samples, wherein S1=N1-n+1;
S7.2, calculating the residual error of the online process-disturbance combined model: e.g. of the typel(t)=yl(t)-Gm,l(q-1)ul(t) wherein el(t) represents the on-line process-perturbation joint model residual error at the tth sampling instant of the ith window, yl(t) represents the process output vector at the tth sampling instant of the ith window, ul(t) denotes the input vector at the tth sampling instant of the l-th window, t denotes the sampling instant, Gm,l(q-1) Representing a Process model, q, used by an EWMA batch-to-batch controller in an on-line regime-1Denotes a difference operator, where l is 1,2, …, S1;
S7.3, acquiring a process input data set of the current working condition by using the process output vector, the process input vector and the process-disturbance combined model residual error which are acquired in real timeAnd output data set Yl 0:
Wherein the content of the first and second substances,representing the on-line process input vector and,representing an online process-perturbation joint model residual vector,representing an online process output vector;
s7.4, constructing a matrix XlAnd Yl:
Wherein u isi,lRepresents the process input vector, u ″, in the ith window of the online datai,lThe process input vector representing the normalized l-th window, i.e.yj,lRepresents the process output vector, y ″, of the ith window of online dataj,lThe process output vector representing the normalized l-th window, i.e.ej,lProcess-perturbation joint model residual vector representing the ith window of online data, ej,l=(ej,l(t)), ej,l(t)=yj,l(t)-(Gm,l(q-1))jul(t),(Gm,l(q-1))jProcess model G representing EWMA inter-batch controller usage in the ith window of online datam,l(q-1) J-th line of (1), yj,l(t) denotes the jth process output at the tth sampling instant of the ith window of online data, ul(t) represents the vector formed by all process inputs at the tth sampling time of the ith window of online data, e ″j,lRepresenting the normalized process-perturbation joint model residual,
s7.5, constructing a Hankel matrix Xp,lAnd Xf,l:
Wherein p isp+1,lRepresenting a history data vector at the p +1 th sampling instant in the ith window of line data, i.e. pp+1,l=[xl(p)T … xl(1)T yl(p)T … yl(1)T]T,xl(p) a representation matrixP column of (2), xl(1) Representation matrixThe p-th column of (2),representation matrix XlTranspose of (y)l(p) represents a matrix Yl TP column, yl(1) Representation matrix Yl TColumn 1, Yl TRepresentation matrix YlTransposing; f. ofp+1,lThe vector of predicted data representing the p +1 th sampling instant in the l window of line data, i.e. fp+1,l=[yl(p+1)T yl(p+2)T … yl(p+f-1)T]T,yl(p +1) represents Yl TP +1 column, yl(p +2) represents Yl TP +2 column, yl(p + f-1) represents Yl TP + f-1 column (b);
s7.6, acquiring control performance monitoring quantity eta of the current working condition by using online dataCPI:
Wherein the content of the first and second substances,indicating the control performance monitoring quantity, p, of the ith window of the on-line datak,lRepresentation matrix Xp,lThe k thA column vector;
s7.7, control Upper Limit UP according to control Performance monitoring amountCPIJudgment ofWhether or not less than UPCPIIf, ifLess than UPCPIThen the system performance is better, ifGreater than UPCPIThe system performance is degraded.
Step S9 includes the following steps:
s9.1, obtaining a reference working condition model residual error by using online data:wherein v isr,l(t) represents the reference operating mode model residual error at the tth sampling moment of the ith window of the online data,representing the reference condition disturbance model estimate, yl(t) an online data process output vector, u, at the tth sampling instant of the ith windowl(t) an on-line data process input vector, G, representing the t-th sampling instant of the l-th windowm,l(q-1) Representing a process model used by the EWMA batch controller in the ith window of the online data;
s9.2, calculating model mismatching/disturbance dynamic combined monitoring quantity eta by utilizing online collected input data and output dataPDMI: Wherein the content of the first and second substances,has a value range of (0, 1)],εr(t) reference for the t-th sampling instantEstimate of operating condition white noise, | cov (εr(t)) | denotes εr(t) determinant of covariance matrix, vr,l(t) represents the on-line data reference case model residual at the tth sampling instant of the ith window, | cov (v)r,l(t)) | denotes vr,l(t) determinant of covariance matrix;
s9.3, combining control upper limit UP of model mismatch/disturbance dynamic joint monitoring quantityPDMIThe factors for controlling the performance degradation are preliminarily diagnosed if the current working condition is metGreater than UPPDMIIf the model mismatch or the external disturbance dynamics is changed, the system performance is reduced due to the model mismatch or the external disturbance dynamics; if the current operating condition isLess than UPPDMIThen changes in the controller tuning parameters are a factor that causes degradation in system performance.
Step S11 includes the following steps:
s11.1, calculating interference characteristic monitoring quantity eta of online dataDVI:Wherein the content of the first and second substances,representing the interference characteristic monitoring quantity of the online data corresponding to the ith window,for characterizing the change of the white noise variance, ε, in the actual operating conditionsr(t) represents the white noise estimate of the reference condition at the tth sampling time, εh,l(t) represents the white noise estimation value of the actual working condition at the t sampling moment of the ith window in the online monitoring stage, | cov (epsilon)h,l(t)) | denotes εh,lDeterminant of covariance matrix of (t), | cov (εr(t)) | denotes εr(t) determinant of covariance matrix;
s11.2, calculating the actual working condition model residual error of the online data:wherein v ish,l(t) represents the model residual error of the online data actual condition corresponding to the ith window,on-line data actual condition disturbance model estimation value y representing ith windowl(t) an online data process output vector, u, at the tth sampling instant of the ith windowl(t) an online data process input vector, G, for the tth sampling instant of the l-th windowm,l(q-1) Representing a process model used by the EWMA batch controller in the ith window of the online data;
s11.3, calculating disturbance model monitoring quantity eta of online dataDMI:Wherein the content of the first and second substances,representing the monitored quantity, v, of the disturbance model corresponding to the l-th windowr,l(t) represents the on-line data reference condition model residual at the tth sampling instant of the ith window, vh,l(t) represents the on-line data real-time model residual error at the tth sampling time of the ith window, J (f (v)r,l(t)),g(vh,l(t))) represents vh,l(t) and vr,l(t) KL divergence;
s11.4, calculating model mismatch monitoring quantity eta of online dataPMI:Wherein the content of the first and second substances,model mismatch monitoring quantity, epsilon, of the on-line data corresponding to the ith window of the on-line datah,l(t) denotes the ith of the on-line dataWhite noise estimation value of practical working condition at the t-th sampling moment of window vh,l(t) represents the real model residual at the tth sampling instant of the l windows of online data, cov (εh,l(t)) represents εh,l(t) determinant of covariance matrix, cov (v)h,l(t)) represents vh,l(t) determinant of covariance matrix;
s11.5, combining the lower control limit LP of the interference characteristic monitoring quantityDVIUpper limit UP of control of the monitored quantity of interference characteristicsDVILower control limit LP of disturbance model monitoring quantityDMIAnd upper control limit UP of model mismatch monitoring quantityPMIFurther diagnosing and identifying the factors causing the performance degradation of the EWMA batch-to-batch control system, and a plurality of disturbance characteristic monitoring quantitiesGreater than UPDVIOr less than LPDVIIf so, the white noise variance changes to cause the performance of the EWMA batch-to-batch control system to be reduced; if the model monitoring quantity is disturbedLess than LPDMIIf so, the performance of the EWMA batch control system is reduced due to the change of the external disturbance model; monitoring quantity if model mismatchingGreater than UPPMIThen the model mismatch causes the EWMA inter-batch control system performance to degrade.
Compared with the prior art, the invention has the following beneficial effects:
1) when monitoring the control performance of a semiconductor process batch control system, the control performance monitoring quantity constructed by adopting a typical variable analysis method is closely related to controller regulation, model mismatch and disturbance dynamics according to the relation between process output and process input and a process-disturbance combined model residual error; compared with other control performance evaluation indexes, the control performance monitoring quantity provided by the invention directly reflects the influence of controller regulation, model mismatch and disturbance dynamics on the control performance.
2) When the control performance of a semiconductor process batch control system is diagnosed, four diagnosis statistics are established, wherein the four diagnosis statistics are as follows: model mismatch/disturbance dynamic monitoring quantity, interference characteristic monitoring quantity, disturbance model monitoring quantity and model mismatch monitoring quantity; the model mismatch/disturbance dynamic monitoring quantity is not influenced by the adjusting parameters of the controller, the disturbance characteristic monitoring quantity can separate the white noise variance change from other factors influencing the control performance, the disturbance model monitoring quantity can separate the disturbance model change from other factors influencing the control performance, and the model mismatch monitoring quantity separates the model mismatch from other factors influencing the control performance.
3) The method can effectively monitor the control performance change condition of the system and can also effectively distinguish the influence of three factors of model mismatch, disturbance dynamics and controller adjusting parameters on the control performance, when the control performance is reduced, the closed-loop system needs to be shut down, and a system identification experiment is carried out on the closed-loop system to diagnose the reason of the reduction of the control performance of the system.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flow chart of the present invention;
FIG. 2 is a schematic diagram of a CMP process of the present invention;
FIG. 3 is a schematic diagram of the control performance monitoring index and each diagnostic index when the model is mismatched according to the present invention, wherein (a) is a monitoring graph of the control performance monitoring amount, (b) is a monitoring graph of the model mismatch/disturbance dynamics monitoring amount, (c) is a monitoring graph of the disturbance characteristic monitoring amount, (d) is a monitoring graph of the disturbance model monitoring amount, and (e) is a monitoring graph of the model mismatch monitoring amount;
FIG. 4 is a schematic diagram of the control performance monitoring index and each diagnostic index when the white noise variance changes according to the present invention, wherein (a) is a monitoring graph of the monitoring amount of control performance, (b) is a monitoring graph of the monitoring amount of model mismatch/disturbance dynamics, (c) is a monitoring graph of the monitoring amount of disturbance characteristic, (d) is a monitoring graph of the monitoring amount of disturbance model, and (e) is a monitoring graph of the monitoring amount of model mismatch;
FIG. 5 is a diagram of a control performance monitoring index and diagnostic indices when a controller parameter changes according to the present invention, wherein (a) is a monitoring graph of a control performance monitoring amount, (b) is a monitoring graph of a model mismatch/disturbance dynamics monitoring amount, (c) is a monitoring graph of a disturbance characteristic monitoring amount, (d) is a monitoring graph of a disturbance model monitoring amount, and (e) is a monitoring graph of a model mismatch monitoring amount;
FIG. 6 is a schematic diagram of the control performance monitoring index and each diagnostic index when the disturbance model is changed, wherein (a) is a monitoring graph of the control performance monitoring amount, (b) is a monitoring graph of the model mismatch/disturbance dynamics monitoring amount, (c) is a monitoring graph of the disturbance characteristic monitoring amount, (d) is a monitoring graph of the disturbance model monitoring amount, and (e) is a monitoring graph of the model mismatch monitoring amount, according to the present invention;
FIG. 7 is a schematic diagram of the control performance monitoring index and each diagnostic index when the model is mismatched and the white noise variance is changed, wherein (a) is a monitoring graph of the monitoring quantity of the control performance, (b) is a monitoring graph of the monitoring quantity of the model mismatch/disturbance dynamics, (c) is a monitoring graph of the monitoring quantity of the disturbance characteristic, (d) is a monitoring graph of the monitoring quantity of the disturbance model, and (e) is a monitoring graph of the monitoring quantity of the model mismatch;
fig. 8 is a schematic diagram of the control performance monitoring index and each diagnostic index when the model is mismatched and the disturbance model is changed according to the present invention, where (a) is a monitoring map of the control performance monitoring amount, (b) is a monitoring map of the model mismatch/disturbance dynamics monitoring amount, (c) is a monitoring map of the disturbance characteristic monitoring amount, (d) is a monitoring map of the disturbance model monitoring amount, and (e) is a monitoring map of the model mismatch monitoring amount.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.
As shown in fig. 1, an embodiment of the invention provides a method for diagnosing control performance of a semiconductor manufacturing lot-to-lot control system, which includes the following steps:
s1, obtaining N groups of input data and output data of historical normal working conditions of the EWMA batch control system in the semiconductor manufacturing process as sample data, dividing the sample data into S +1 windows, and calculating a white noise estimation value epsilon of the reference working condition by using the input data and the output data of the first windowrAnd reference working condition disturbance model estimation valueObtaining process-disturbance combined model residual e (t), process data setAnd output data set Y1 0Collecting the process dataIs subtracted from the ith columnProcess data setMean of all samples in column i divided by the process data setObtaining a matrix X of the reference working condition by the standard deviation of the sample of the ith column1Will output data set Y1 0Is subtracted from the output data set Y1 0Is divided by the output data set Y after averaging all samples in column i1 0Obtaining a matrix Y of the reference working condition by the standard deviation of the sample of the ith column1Construction of Hankel matrix XpAnd XfAnd projection matrix Jq。
Step S1 includes:
s1.1, acquiring input data and output data of N groups of historical normal working conditions in a semiconductor manufacturing process with an EWMA batch controller as sample data, dividing the sample data into S +1 windows, wherein each window comprises N groups of samples, and S is N-N. The calculation process of the window S is as follows: s ═ N/d ], where d is the window moving step length, [ · ] denotes rounding the data down, in this example, d ═ 1.
S1.2, regarding a first window in the S +1 windows acquired in the step S1.1 as a reference working condition, and respectively performing centralization processing on input data and output data of the first window:
wherein u' (t) represents the process input vector at the t-th sampling time after the centering process, u (t) represents the input vector at the t-th sampling time of the first window,representing the mean vector, m, of the input vectors at the t-th sampling instant of the first windowuRepresenting the number of input vectors, t representing the sampling instant, n representing the firstThe number of samples in the window, y' (t) represents the process output vector at the t-th sampling instant after the centering process, y (t) represents the output vector at the t-th sampling instant of the first window,mean vector, m, representing the output vector at the t-th sampling instant of the first windowyIndicating the number of output vectors.
S1.3, obtaining an estimated value of white noise of a reference working condition:
εr(t)=y′P(t){I-YP′(t)T[YP′(t)YP′(t)T]-1YP′(t)},
wherein epsilonr(t) represents a reference condition white noise estimation value y 'at the t-th sampling time'P(t)=[y′(t) … y′(t-P+1)]Representing a data vector constructed from a centralised process output vector Y' (t), YP′(t)=[y′P(t-1)T… y′P(t-L)T]TIs represented by a data vector y'P(t) constructing a data matrix, P representing the size of a data window for estimating white noise, L representing the data matrix YP' (T) and T denotes a transpose operation.
S1.4, constructing an autoregressive moving average model of the process output data after centralization processing and with out-of-band source input:
wherein the content of the first and second substances,denotes a delay factor, phi1,…,φICoefficient, phi, representing the autoregressive partI+1,…,φI+KCoefficient of exogenous input, phiI+K+1, …,φI+K+JCoefficient representing moving average, I represents maximum order of autoregressive part, and K represents exogenous inputMaximum order of entry; j denotes the maximum order of the moving average.
S1.5, acquiring coefficient vectors and orders of an autoregressive moving average model with out-of-band source input according to an adaptive minimum absolute value contraction and operator selection method:
wherein the content of the first and second substances, YW(t)=[y′(t) … y′(t-W+1)]T(ii) a W denotes the window size of the sampled data, YW(t) denotes a W × 1-dimensional data matrix, HW(t) represents a W × (I + K + J) dimensional data matrix;expressing the adaptive minimum absolute value shrinkage and selection operator method to estimate the coefficient vector of the autoregressive moving average model, i.e.Denotes the coefficients of the estimated autoregressive moving average model, phi denotes the coefficient vector of the actual but unknown autoregressive moving average type, phi ═ phi1,…,φI+K+J]λ denotes an adjustable parameter controlling the penalty factor in the adaptive minimum absolute value shrinkage and selection operator method,j-th coefficient phi in coefficients representing autoregressive moving average modeljThe weighting factor of (2).
S1.6, calculating a process-disturbance combined model residual error according to an input vector and an output vector of a first window:
e(t)=y(t)-Gm(q-1)u(t),
wherein e (t) represents the process-perturbation joint model residual, Gm(q-1) Indicating EWMA inter-batch controller usage in the first windowProcess model of (a), q-1A difference operator is represented.
S1.7, acquiring a process data set of a reference working condition by utilizing a process input vector, a process output vector and a process-disturbance combined model residual error of a first windowAnd output data set Y1 0:
Wherein the content of the first and second substances,which represents the input vector of the process,representing the process-perturbation joint model residual vector,representing the process output vector.
S1.8, calculating a mean vector and a standard deviation vector of process input vectors of a first window:
wherein the content of the first and second substances,is the mean vector, σ, of the process input vectors at the t-th sampling instant of the first windowu,rThe process of the first window inputs the vector of standard deviation of the vector;
calculating a mean vector and a standard deviation vector of the output vector of the first window process:
wherein the content of the first and second substances,is the mean vector, σ, of the process output vectors at the t-th sampling instant of the first windowy,rThe process of the first window outputs a vector of standard deviations of the vectors;
calculating a mean vector and a standard deviation vector of a first window process-disturbance combined model residual:
wherein the content of the first and second substances,mean vector, σ, of the process-perturbation combined model residuals for the first windowe,rThe process-perturbation for the first window is the standard deviation vector of the joint model residual.
S1.9, constructing a matrix X1And Y1:
Wherein u isiRepresents the ith process input vector, i 1, …, mu,muDenotes the number of input vectors, t denotes the sampling time, ui"represents the i-th process input vector after normalization, i.e. Means representing the ith process input vector, (σ)u,r)iRepresents the standard deviation of the ith process input vector; y isjRepresents the jth process output vector, j ═ 1, …, my,myIndicating the number of output vectors, yj"represents the normalized j-th process output vector, i.e. Means for representing the jth process output vector, (σ)y,r)jRepresents the standard deviation of the jth process output vector; e.g. of the typej(t) denotes the jth process-perturbation joint model residual vector, where ej=(ej(t)), ej(t)=yj(t)-(Gm(q-1))ju(t),(Gm(q-1))jRepresenting the process model G used in the first windowm(q-1) J-th line of (1), yj(t) denotes the jth process output at the tth sampling instant, u (t) denotes the column vector formed by all process inputs at the tth sampling instant in the first window, e ″jRepresents the normalized j process-perturbation joint model residual vector, means for representing the jth process-perturbation combined model residual, (σ)e,r)jRepresents the standard deviation of the jth process-perturbation combined model residual.
S1.10, constructionHankel matrix XpAnd Xf:
Wherein m is mu+2my,pp+1Representing the historical data vector at the p +1 th sampling instant, i.e. pp+1=[x(p)T … x(1)T y(p)T … y(1)T]TX (p) represents a matrixP column of (2), x (1) represents a matrixThe number 1. sup. st column of (a),representing matrix X1Y (p) denotes a matrix Y1 TY (1) denotes the matrix Y1 TColumn 1, Y1 TRepresentation matrix Y1Transposing; f. ofp+1The vector of prediction data representing the p +1 th sampling instant, i.e. fp+1=[y(p+1)T y(p+2)T … y(p+f-1)T]TY (p +1) represents Y1 TColumn p +1, Y (p +2) represents Y1 TIn the p +2 th column, Y (p + f-1) represents Y1 TM denotes the number of vectors of the history data vector and the prediction data vector constructed from n sets of observation data, and M is n-p-f + 1.
S1.11, calculating a unitary matrix V: h ═ U ∑ VTWherein V represents a unitary matrix constructed when singular value decomposition is performed on the matrix H,is represented by XpAnd XfThe constructed matrix Hankel matrix is used as a matrix,represents the sample covariance of the historical data vector,represents the sample covariance of the prediction data vector,representing the cross covariance of the historical data vector and the predicted data vector.
S1.12, calculating a projection matrix Jq:Wherein, VqRepresenting a matrix constructed from the first q columns of the unitary matrix V,represents the Hankel matrix XpThe covariance matrix of (2).
S2, constructing a process data set using the input data and the output data of the k' th windowAnd outputting the data setCollecting process dataColumn i minus the process data setMean of all samples in column i divided by the process data setObtaining a matrix X of actual working conditions by the standard deviation of the sample of the ith columnk'Will output the data setI th of (1)Column-minus output datasetIs divided by the output data set after averaging all samples in column iObtaining a matrix Y of actual working conditions by the standard deviation of the sample of the ith columnk'Acquiring control performance monitoring quantity of an EWMA batch-to-batch control system by adopting a typical variable Analysis (CVA)Where k' is 2,3, …, S + 1.
Step S2 includes:
s2.1, obtaining a process-disturbance combined model residual error of a k 'th window by using input data and output data of the k' th window: e.g. of the typek'(t)=yk'(t)-Gm,k'(q-1)uk' (t) wherein ek'(t) denotes the process-perturbation joint model residual at the t-th sampling instant of the k' -th window, yk'(t) denotes the kth' window process output vector at the tth sampling instant uk'(t) represents the process input vector for the kth window at the tth sampling instant, Gm,k'(q-1) Representing the process model used by the EWMA batch controller in the current operating regime.
S2.2, acquiring a process input data set under the current working condition according to the process input vector and the output vector of the kth window and the process-disturbance combined model residual error of the kth windowAnd outputting the data set
Wherein the content of the first and second substances,the process input vector representing the kth window,the process-perturbation joint model residual vector representing the kth window,the process output vector representing the k' th window.
S2.3, constructing a matrix Xk'And Yk':
Wherein u isi,k'The process input vector, u ", representing the k' th windowi,k'The process input vector representing the normalized k' th window, i.e.yj,k'Represents the process output vector, y ″, of the k' th windowj,k'The process output vector representing the normalized k' th window, i.e.ej,k'Process-perturbation joint model residual vector representing the kth window, ej,k'=(ej,k'(t)), ej,k'(t)=yj,k'(t)-(Gm,k′(q-1))juk'(t),yj,k'(t) denotes the jth process output, u, at the tth sampling instant in the kth windowk'(t) represents the column vector formed by all process inputs at the tth sampling instant in the kth window, (G)m,k′(q-1))jRepresents Gm,k′(q-1) Line j, e ″)j,k'Representing the process-perturbation combined model residual of the normalized k' th window, i.e.
S2.4, constructing a Hankel matrix Xp,k'And Xf,k':
Wherein p isp+1kRepresenting the historical data vector at the p +1 th sampling instant in the k' th window, i.e. pp+1,k'=[xk'(p)T … xk'(1)T yk'(p)T … yk'(1)T]T,xk'(p) a representation matrixP column of (2), xk'(1) Representation matrixThe number 1. sup. st column of (a),representation matrix Xk'Transpose of (y)k'(p) a representation matrixP column, yk'(1) Representation matrixThe number 1. sup. st column of (a),representation matrix Xk'Transposing; f. ofp+1kDenotes the vector of prediction data at the p +1 th sampling instant in the k' th window, i.e. fp+1,k'=[y(k')(p+1)T y(k')(p+2)T … y(k')(p+f-1)T]T,y(k')(p +1) representsP +1 column, y(k')(p +2) representsP +2 column, y(k')(p + f-1) representsColumn p + f-1.
S2.5, obtaining control performance monitoring quantity of the EWMA batch control system by adopting a typical variable analysis methodComprises the following steps:wherein the content of the first and second substances,represents the amount of control performance monitoring, J, of the EWMA batch-to-batch control system corresponding to the kth windowqRepresenting a projection matrix, pk,k'Representation matrix Xp,k'The k-th column of (1).
S3, according to the reference working condition disturbance model estimated value in the step S1Obtaining reference working condition model residual error v from input data and output data of k' th windowr,k'(t) and model mismatch/perturbation dynamics joint monitoring volume
Step S3 includes:
s3.1, disturbing the model estimated value according to the reference working conditionObtaining reference working condition model residual error v from input data and output data of k' th windowr,k'(t):Wherein v isr,k'(t) reference behavior model residual, y, at the t-th sampling time of the k' -th windowk'(t) represents the process output vector at the t-th sampling instant of the k' -th window, uk'(t) represents the process input vector at the t-th sampling instant of the k' -th window, Gm,k'(q-1) Representing the process model used by the EWMA batch controller in the k' th window.
S3.2, according to the model residual error v of the reference working conditionr,k'(t) obtaining model mismatch/disturbance dynamic combined monitoring quantity by white noise estimated value of reference working conditionWherein the content of the first and second substances,represents the model mismatch/disturbance dynamic joint monitoring quantity corresponding to the k' th window,has a value range of (0, 1)],εr(t) the white noise estimation value of the reference condition at the t-th sampling moment, vr,k'(t) represents the reference condition model residual at the t-th sampling instant in the kth' window, | cov (εr(t)) | denotes εrDeterminant of covariance matrix of (t), | cov (v)r,k'(t)) | denotes vr,k'(t) determinant of covariance matrix.
S4, obtaining the white noise estimation value epsilon of the practical working condition corresponding to the k 'th window by using the input data and the output data of the k' th windowh,k'(t) and actual condition disturbance model estimation valueAnd according to the actual working condition disturbance model estimated valueObtaining an actual condition modelResidual vh,k'(t)。
Step S4 includes:
s4.1, carrying out centralized processing on input data and output data of a k' th window:
wherein u'k'(t) represents the process input vector at the t-th sampling instant of the k' -th window after the centering process, uk'(t) represents the process input vector at the t-th sampling instant of the k' -th window that is not centered,mean vector, y ', of process input vectors representing the t-th sampling instant of the k ' -th window 'k'(t) represents the process output vector at the t-th sampling instant of the k' -th window after the centering process, yk'(t) represents the process output vector at the t-th sampling instant of the k' -th window that is not centered,the mean vector of the process output vectors at the t-th sampling instant of the k' -th window is represented.
S4.2, calculating an estimated value of white noise under an actual working condition: epsilonh,k'(t)=y′P,k'(t){I-Y′P,k'(t)T[Y′P,k'(t)Y′P,k'(t)T]-1Y′P,k'(t) }, in which εh,k'(t) represents an actual working condition white noise estimated value y 'of the acquired kth sampling moment of the kth window'P,k'(t)=[y′k'(t) … y′k'(t-P+1)]Represents the process output vector y ' using the centered k ' th window 'k'(t) constructed data vector, Y'P,k'(t)=[y′P,k'(t-1)T … y′P,k'(t-L)T]TIs represented by a data vector y'P,k'(t) the constructed data matrix.
S4.3, constructing an autoregressive moving average model of the out-of-band source input of the process output vector of the kth window:
wherein the content of the first and second substances,which is indicative of the delay factor, is,the coefficients of the auto-regressions are represented,the coefficient representing the input of the external source,coefficient representing moving average, Ik' represents the maximum order of autoregressive, Kk' represents the maximum order of exogenous input; j. the design is a squarek' denotes the maximum order of the moving average.
S4.4, acquiring coefficient vector and order of the autoregressive moving average model with out-of-band source input according to the adaptive minimum absolute value contraction and operator selection method:
wherein the content of the first and second substances, Wk' denotes the window size of the sampled data,represents WkA data matrix of dimension' x 1,represents Wk'×(Ik'+Kk'+Jk') A dimensional data matrix;the method representing the adaptive minimum absolute value shrinkage and selection operator estimates the coefficient vector of the autoregressive moving average model, i.e.Coefficient, phi, representing the estimated autoregressive moving average modelk'A coefficient vector representing a real but unknown type of auto-regressive moving average, j-th coefficient phi in coefficients representing autoregressive moving average modelj,k'The weighting factor of (2).
S4.5, obtaining an estimated value of the actual working condition disturbance model according to the autoregressive moving average model with out-of-band source input:
wherein the content of the first and second substances,and representing the estimated value of the actual working condition disturbance model of the k' th window.
S4.6, calculating the residual error of the actual working condition model:
wherein v ish,k'(t) actual condition model of t sampling time of k' th windowThe residual error is a residual error that is,actual condition disturbance model estimation value representing k' th windowInverse of (y)k'(t) represents the process output vector at the t-th sampling instant of the k' -th window, uk'(t) represents the process input vector at the t-th sampling instant of the k' -th window, Gm,k′(q-1) Representing the process model used by the EWMA batch controller in the k' th window.
S5, according to the reference working condition white noise estimated value epsilon in the step S1rAnd the white noise estimate of the actual condition ε in step S4h,k'(t) calculating an interference characteristic monitoring quantityAccording to the reference working condition model residual v in the step S3r,k'(t) and the actual condition model residual v in step S4h,k'(t) calculating the amount of monitoring of the disturbance modelAccording to the actual working condition white noise estimated value epsilon in the step S4h,k'(t) and the actual condition model residual vh,k'(t) obtaining a model mismatch monitoring quantity
Step S5 includes:
s5.1, calculating interference characteristic monitoring quantityWherein epsilonr(t) represents the white noise estimation value of the reference condition at the t-th sampling moment, epsilonh,k'(t) represents the white noise estimate for the actual condition at the t-th sampling instant in the kth' window, | cov (εh,k'(t)) | denotes εh,k'Determinant of covariance matrix of (t), | cov (εr(t)) | denotes εr(t) determinant of covariance matrix.
S5.2, calculating the monitoring quantity of the disturbance modelWherein the content of the first and second substances,represents the perturbation model monitoring quantity of the k' th window,has a value range of (0, 1)]If, ifNear or equal to 1, the perturbation model is unchanged, vr,k'(t) represents the reference operating condition model residual at the t-th sampling moment in the k' -th window, vh,k'(t) represents the actual condition model residual at the t-th sampling instant in the k' -th window, J (f (v)r,k'(t)),g(vh,k'(t))) represents vh,k'(t) and vr,k'(t) KL divergence, expressed as:
wherein, f (v)r,k'(t)) represents v constructed using the nuclear density estimation methodr,k'(t) probability density function, f (v)h,k'(t)) represents v acquired by the kernel density estimation methodh,k'(t) probability density function, i ═ 1,2, …, Nf,NfRepresenting the total number of independent identically distributed sample points produced by the kernel density estimate.
S5.3, calculating model mismatch monitoring quantityWherein epsilonh,k'(t) represents the white noise estimation value of the actual working condition at the t sampling moment in the k' th window, vh,k'(t) represents the t sample in the k' windowActual condition model residual error of moment, | cov (εh,k'(t)) | denotes εh,k'Determinant of covariance matrix of (t), | cov (v)h,k'(t)) | denotes vh,k'(t) determinant of covariance matrix.
S6, respectively obtaining the control upper limit UP of the control performance monitoring quantity by adopting a kernel density estimation methodCPIUpper control limit UP of model mismatch/disturbance dynamic joint monitoring quantityPDMIUpper limit UP of control of the monitored quantity of interference characteristicsDVILower limit of control LP of disturbance characteristic monitoring amountDVILower control limit LP of disturbance model monitoring quantityDMIAnd the upper control limit UP of the model mismatch monitoring quantityPMI。
Step S6 includes:
s6.1, calculating the control upper limit UP of the control performance monitoring quantityCPI:Wherein the content of the first and second substances,is the control performance monitoring amount corresponding to the kth window, K' is 2, 3.., S +1, h represents the kernel bandwidth, and K (·) represents the kernel density estimation with the kernel being a radial basis function.
S6.2, calculating the control upper limit UP of the model mismatch/disturbance dynamic combined monitoring quantityPDMI: Wherein the content of the first and second substances,is the model mismatch/disturbance dynamic joint monitoring quantity corresponding to the k' th window.
S6.3, calculating the control upper limit UP of the interference characteristic monitoring quantityDVIAnd a lower control limit LPDVI:Wherein the content of the first and second substances,is the interference characteristic monitoring quantity corresponding to the k' th window.
S6.4, calculating a control lower limit LP of the monitoring quantity of the disturbance modelDMI:Wherein the content of the first and second substances,is the disturbance model monitoring quantity corresponding to the k' th window.
S6.5, calculating the control upper limit UP of the model mismatch monitoring quantityPMI:Wherein the content of the first and second substances,is the interference characteristic monitoring quantity corresponding to the k' th window.
S7, collecting N1 groups of input data and output data of the EWMA batch control system of the semiconductor process on line, and obtaining the control performance monitoring quantity eta of the current working conditionCPIAccording to the control upper limit UP in step S6CPIAnd judging whether the control performance of the closed-loop system is reduced or not in real time.
Step S7 includes:
s7.1, collecting N1 groups of input data and output data of the EWMA batch control system of the semiconductor process on line as actual working condition sample data, and dividing the actual working condition sample data into S1An online window, each window containing n groups of samples, wherein S1=N1-n+ 1。
S7.2, calculating the residual error of the online process-disturbance combined model: e.g. of the typel(t)=yl(t)-Gm,l(q-1)ul(t) wherein el(t) represents the on-line process-perturbation joint model residual error at the tth sampling instant of the ith window, yl(t) represents the process output vector at the tth sampling instant of the ith window, ul(t) denotes an input vector at the tth sampling time of the ith window, and t denotesSampling time, Gm,l(q-1) Representing a Process model, q, used by an EWMA batch-to-batch controller in an on-line regime-1Denotes a difference operator, where l is 1,2, …, S1。
S7.3, acquiring a process input data set of the current working condition by using the process output vector, the process input vector and the process-disturbance combined model residual error which are acquired in real timeAnd output data set Yl 0:
Wherein the content of the first and second substances,representing the on-line process input vector and,representing an online process-perturbation joint model residual vector,representing an online process output vector.
S7.4, constructing a matrix XlAnd Yl:
Wherein u isi,lRepresents the process input vector, u ″, in the ith window of the online datai,lThe process input vector representing the normalized l-th window, i.e.yj,lRepresents the process output vector, y ″, of the ith window of online dataj,lProcess output representing normalized ith windowAmount of, i.e.ej,lProcess-perturbation joint model residual vector representing the ith window of online data, ej,l=(ej,l(t)), ej,l(t)=yj,l(t)-(Gm,l(q-1))jul(t),(Gm,l(q-1))jProcess model G representing EWMA inter-batch controller usage in the ith window of online datam,l(q-1) J-th line of (1), yj,l(t) denotes the jth process output at the tth sampling instant of the ith window of online data, ul(t) represents the vector formed by all process inputs at the tth sampling time of the ith window of online data, e ″j,lRepresenting the normalized process-perturbation joint model residual,
s7.5, constructing a Hankel matrix Xp,lAnd Xf,l:
Wherein p isp+1,lRepresenting a history data vector at the p +1 th sampling instant in the ith window of line data, i.e. pp+1,l=[xl(p)T … xl(1)T yl(p)T … yl(1)T]T,xl(p) a representation matrixP column of (2), xl(1) Representation matrixThe p-th column of (2),representation matrix XlIs rotatedPosition yl(p) represents a matrix Yl TP column, yl(1) Representation matrix Yl TColumn 1, Yl TRepresentation matrix YlTransposing; f. ofp+1,lThe vector of predicted data representing the p +1 th sampling instant in the l window of line data, i.e. fp+1,l=[yl(p+1)T yl(p+2)T … yl(p+f-1)T]T,yl(p +1) represents Yl TP +1 column, yl(p +2) represents Yl TP +2 column, yl(p + f-1) represents Yl TColumn p + f-1.
S7.6, acquiring control performance monitoring quantity eta of the current working condition by using online dataCPI:Wherein the content of the first and second substances,control performance monitor quantity, p, representing the current operating condition corresponding to the ith windowk,lRepresentation matrix Xp,lThe kth column vector of (1).
S7.7, control Upper Limit UP according to control Performance monitoring amountCPIJudgment ofWhether or not less than UPCPIIf, ifLess than UPCPIThen the system performance is better, ifGreater than UPCPIThe system performance is degraded.
S8, if the control performance monitoring quantity etaCPIControl upper limit UP greater than control performance monitoring amountCPIIf the performance of the EWMA inter-batch control system is degraded, the step S9 is executed, otherwise, the EWMA inter-batch control system is executedThe performance is good.
S9, using the reference working condition disturbance model estimated value in the step S1Obtaining the model mismatch/disturbance dynamic combined monitoring quantity eta of the current working condition from the N1 groups of input data and output data in the step S7PDMI。
Step S9 includes:
s9.1, obtaining a reference working condition model residual error by using online data:wherein v isr,l(t) represents the reference operating mode model residual error at the tth sampling moment of the ith window of the online data,and representing the reference working condition disturbance model estimation value.
S9.2, calculating model mismatch/disturbance dynamic combined monitoring quantity etaPDMI:Wherein the content of the first and second substances,has a value range of (0, 1)],εr(t) represents the white noise estimate for the baseline condition, | cov (εr(t)) | denotes εr(t) determinant of covariance matrix, vr,l(t) represents the reference condition model residual at the tth sampling instant, | cov (v)r,l(t)) | denotes vr,l(t) determinant of covariance matrix.
S9.3, combining control upper limit UP of model mismatch/disturbance dynamic joint monitoring quantityPDMIThe factors for controlling the performance degradation are preliminarily diagnosed if the current working condition is metGreater than UPPDMIThe model mismatch or external disturbance dynamics changes, andresulting in system performance degradation; if the current operating condition isLess than UPPDMIThen changes in the controller parameters are a factor that causes degradation in system performance.
S10, if the model mismatching/disturbance dynamic joint monitoring quantity etaPDMIGreater than the upper control limit UP of the combined monitoring quantity of model mismatch/disturbance dynamics in step S6PDMIIf the model mismatch or disturbance dynamics results in performance degradation of the EWMA batch control system, step S11 is executed, otherwise, the controller parameter change results in performance degradation of the EWMA batch control system.
S11, calculating the disturbance characteristic monitoring quantity eta of the current working conditionDVIMonitoring quantity eta of disturbance modelDMIAnd model mismatch monitor ηPMI(ii) a Disturbance characteristic monitoring quantity eta when current working conditionDVIGreater than the upper control limit UP of the disturbance characteristic monitoring amount in step S6DVIOr less than the lower control limit LP of the disturbance characteristic monitored quantityDVIWhen the interference characteristic changes, the performance of the EWMA batch control system is reduced; when the disturbance model monitors the quantity etaDMILower control limit LP less than disturbance model monitoring quantityDMIMeanwhile, the performance of the EWMA batch control system is reduced due to the change of the disturbance model; when model mismatch monitor ηPMIControl upper limit UP greater than model mismatch monitoring amountPMIModel mismatch results in performance degradation of the EWMA batch-to-batch control system.
Step S11 includes:
s11.1, calculating interference characteristic monitoring quantity eta of online dataDVI:Wherein the content of the first and second substances,representing the interference characteristic monitoring quantity of the on-line data corresponding to the ith window, representing the change of white noise variance in actual working conditionr(t) the white noise estimation value of the reference condition at the tth sampling time,εh,l(t) represents the white noise estimate for the actual condition at the tth sampling instant, | cov (εh,l(t)) | denotes εh,l(t) covariance matrix determinant, | cov (εr(t)) | denotes εr(t) covariance matrix determinant.
S11.2, calculating the actual working condition model residual error of the online data:wherein v ish,l(t) represents the model residual error of the online data actual condition corresponding to the ith window,on-line data actual condition disturbance model estimation value y representing ith windowl(t) an online data process output vector, u, at the tth sampling instant of the ith windowl(t) an online data process input vector, G, for the tth sampling instant of the l-th windowm,l(q-1) Representing a process model used by the EWMA batch controller in the ith window of the online data;
s11.3, calculating disturbance model monitoring quantity eta of online dataDMI:Wherein the content of the first and second substances,representing the monitored quantity, v, of the disturbance model corresponding to the l-th windowr,l(t) represents the on-line data reference condition model residual at the tth sampling instant of the ith window, vh,l(t) represents the on-line data real-time model residual error at the tth sampling time of the ith window, J (f (v)r,l(t)),g(vh,l(t))) represents vh,l(t) and vr,l(t) KL divergence.
S11.4, calculating model mismatch monitoring quantity eta of online dataPMI:Wherein the content of the first and second substances,model mismatch monitoring quantity, epsilon, of the on-line data corresponding to the ith window of the on-line datah,l(t) an actual condition white noise estimate, v, at the tth sampling time of the ith window of the on-line datah,l(t) represents the real model residual at the tth sampling instant of the l windows of online data, cov (εh,l(t)) represents εh,l(t) determinant of covariance matrix, cov (v)h,l(t)) represents vh,l(t) determinant of covariance matrix.
S11.5, combining the lower control limit LP of the interference characteristic monitoring quantityDVIUpper limit UP of control of the monitored quantity of interference characteristicsDVILower control limit LP of disturbance model monitoring quantityDMIAnd upper control limit UP of model mismatch monitoring quantityPMIFurther diagnosing and identifying the factors causing the performance degradation of the EWMA batch-to-batch control system if the characteristic monitoring quantity is disturbedGreater than UPDVIOr less than LPDVIIf so, the white noise variance changes to cause the performance of the EWMA batch-to-batch control system to be reduced; if the model monitoring quantity is disturbedLess than LPDMIIf so, the performance of the EWMA batch control system is reduced due to the change of the external disturbance model; monitoring quantity if model mismatchingGreater than UPPMIThen the model mismatch causes the EWMA inter-batch control system performance to degrade.
Specific example 1
Chemical-mechanical planarization (CMP) is the planarization method of choice in the semiconductor industry today, as shown in figure 2. In 1989, Davari et al developed a CMP process for global planarization of interlevel dielectrics. In the early 90 s of the 20 th century, IBM successfully addressed the problem of slow dry etching of copper using the CMP process. In addition, CMP has been integrated with the dual-damascen process to simplify the fabrication steps of conductive lines between successive layers of a multi-layer integrated circuit. As wafer sizes increase to 300 mm or more, equipment and process design improvements address these issues. In addition, as the demand for high-performance products is increasing in the fierce semiconductor market, the quality of semiconductor products is also more and more important as manufacturers increase. This example uses a simulated CMP process. The discrete model of the CMP process is described as follows:
where θ is 0.65, and ∈ (t) ∈ N (0,100). According to the above formula, the process has a manipulated variable and a controlled variable, wherein the manipulated variable u (t) is the platen rotation speed, and the controlled variable y (t) is the removal rate. The removal rate y (t) represents the average of the difference between the initial and final phosphosilicate glass thickness on the wafer. An EWMA inter-batch controller is used to control the removal rate during CMP. The EWMA batch controller consists of an EWMA filter and a minimum beat control rule, and is as follows:
wherein, a (t) represents the output of the EWMA filter, t represents the sampling time, lambda represents the adjusting parameter of the EWMA batch controller, b represents the coefficient of the process model in the EWMA batch controller, tau represents the set value of the controlled variable y (t), and u (t-1) represents the manipulated variable at the t-1 sampling time.
The control performance diagnosis method of the semiconductor process batch control system based on the model residual error provided by the invention is used for diagnosing the control performance of the CMP process, and comprises the following steps:
(1) the method comprises the steps of collecting 1000 groups of input data and output data of historical normal working conditions in a semiconductor manufacturing process of an EWMA batch controller as standard working condition sample data, and obtaining process input data and process output data after centralized processing.
The reference working condition sample data is divided into S +1 windows, and each window comprises 500 groups of samples, wherein S is 500. Firstly, the mean value of the input data of the process is obtained, and the calculation formula isThen, 500 sets of process input data after centralization are obtained:according to 500 sets of collected process output data, firstly, obtaining a mean value of process output, wherein a calculation formula is as follows:then, 500 sets of process output data after centralization are obtained, and the calculation formula is as follows:
(2) acquiring an estimated value of white noise of a reference working condition;
firstly, outputting a data vector constructed by y' (t) according to the centralization processing process acquired in the step (1): y'P(t)=[y′(t) … y′(t-P+1)](ii) a Then, by vector y'P(t) constructed data matrix: y isP′(t)=[y′P(t-1)T … y′P(t-L)T]TWhere P represents the data window size of the estimated white noise. Obtaining an estimated value of the white noise of the reference working condition according to the following formula: epsilonr(t)=y′P(t){I-YP′(t)T[YP′(t)YP′(t)T]-1YP′(t)}。
(3) Obtaining a reference working condition disturbance model estimation value;
(3.1) obtaining an autoregressive moving average model of the out-of-band source input of the centralized process output according to the following formula:
wherein the content of the first and second substances,denotes a delay factor, phi1,…,φICoefficient of autoregressive representationI+1,…,φI+KCoefficient of exogenous input, phiI+K+1, …,φI+K+JRepresenting the coefficient of the moving average, I representing the maximum order of autoregressive, and K representing the maximum order of exogenous input; j represents the maximum order of the moving average, y '(t) represents the process output after the centering process obtained in step (1), u' (t) represents the process input after the centering process obtained in step (1), εrAnd (t) representing the reference working condition white noise estimated value obtained in the step (2).
(3.2) according to the self-adaptive minimum absolute value contraction and operator selection method, obtaining the coefficient vector and the order of the autoregressive moving average model with out-of-band source input:
wherein the content of the first and second substances,YW(t)=[y′(t) … y′(t-W+1)]T(ii) a W denotes the window size of the sampled data, YW(t) denotes a W × 1-dimensional data matrix, HW(t) represents a W × (I + K + J) dimensional data matrix; y '(t) represents the process output after the centering process, u' (t) represents the process input after the centering process, εr(t) represents the acquired white noise estimate of the reference condition,the coefficient vector representing the adaptive minimum absolute value shrinkage and selection operator method for estimating the autoregressive moving average model, i.e. Representing the coefficients of the estimated autoregressive moving average model, I representing the maximum order of the autoregressive portion, and K representing the maximum order of the exogenous input portion; j denotes the maximum order of the moving average part, phi denotes the coefficient vector of the actual but unknown autoregressive moving average type, phi ═ phi1,…,φI+K+J]λ represents an adjustable parameter for controlling penalty factors in the adaptive minimum absolute value shrinkage and selection operator method,j-th coefficient phi in coefficients representing autoregressive moving average modeljThe weighting factor of (2).
(3.3) according to the autoregressive moving average model of the out-of-band source input estimated in the step (3.2), acquiring a reference working condition disturbance model estimated value according to the following formula:
wherein the content of the first and second substances,coefficients representing the above estimated autoregressive portion and moving average portion, coefficients of an autoregressive moving average model,and representing the reference working condition disturbance model estimation value.
(4) Obtaining process-disturbance combined model residual
Obtaining a process-perturbation combined model residual error of the first window according to the following formula: e (t) ═ y (t) — Gm(q-1) u (t); wherein e (t) represents the process-perturbation combined model residual error, y (t) represents the process output at the tth sampling moment, u (t) represents the process input at the tth sampling moment, Gm(q-1) Representing the process model used by the EWMA batch controller in the first window, q-1A difference operator is represented.
(5) Construction of Hankel matrix XpAnd Xf
(5.1) acquiring a process data set of the reference working condition according to the following formula by using the process output, the process input and the process-disturbance combined model residual error of the first windowAnd output data set Y1 0:
Wherein the content of the first and second substances,representing the process input vector, muDenotes the number of input variables, mu=1,Representing the process-perturbation joint model residual vector,representing the process output vector, myDenotes the number of output variables, my=1。
(5.2) obtaining the process input mean vector and the standard deviation vector of the first window according to the following formula:
wherein the content of the first and second substances,is the over-sampling of the tth sampling time of the first windowMean vector of range inputs, σu,rThe standard deviation vector of the process input, m, for the first windowuDenotes the number of input variables, mu=1,myDenotes the number of input variables, myT denotes the sampling time, n denotes the number of samples of the first window, n is 500, u1(t) represents a first input variable,denotes the m-thuAn input variable; obtaining a mean vector and a standard deviation vector output by the first window process according to the following formula:
wherein the content of the first and second substances,is the mean vector, σ, of the process outputs at the t-th sampling instant of the first windowy,rThe standard deviation vector of the process output of the first window, myDenotes the number of output variables, myN denotes the number of samples of the first window, n is 500, y1(t) represents a first output variable,denotes the m-thyAn output variable; obtaining a mean vector and a standard deviation vector of a first window process-disturbance combined model residual error according to the following formula:
wherein the content of the first and second substances,mean vector, σ, of the process-perturbation combined model residuals for the first windowe,rThe standard deviation vector of the process-perturbation combined model residuals of the first window, myDenotes the number of output variables, my=1,e1(t) represents the first process-perturbation joint model residual,denotes the m-thyProcess-perturbation joint model residuals.
(5.3) constructing matrix X according to the following equation1And Y1
Wherein u isiRepresents the ith process input vector, i 1, …, mu,ui"represents the i-th process input vector after normalization, i.e. Means representing the ith process input vector, (σ)u,r)iRepresents the standard deviation of the ith process input vector; y isjRepresents the jth process output vector, j ═ 1, …, my,yj"represents the normalized j-th process output vector, i.e. Represents the mean of the jth process output vector (σ)y,r)jRepresents the standard deviation of the jth process output vector; e.g. of the typej(t) denotes the j-th process-perturbation combined model residual vector, j is 1, …, my,ej=(ej(t)),ej(t)=yj(t)-(Gm(q-1))juj(t),(Gm(q-1))jRepresentation process model Gm(q-1) J-th line of (1), yj(t) denotes the jth process output at the tth sampling instant uj(t) denotes the process input at the tth sampling instant, e ″jRepresents the normalized j process-perturbation joint model residual vector, means for representing the jth process-perturbation combined model residual, (σ)e,r)jRepresents the standard deviation of the jth process-perturbation combined model residual.
(5.4) construction of Hankel matrix X according to the following formulapAnd Xf:
Wherein m is mu+2my,pp+1Representing the historical data vector at the p +1 th sampling instant, i.e. pp+1=[x(p)T … x(1)T y(p)T … y(1)T]TX (p) represents a matrixP column of (2), x (1) represents a matrixThe number 1. sup. st column of (a),representation matrix X1Is transferred toY (p) denotes a matrix Y1 TY (1) denotes the matrix Y1 TColumn 1, Y1 TRepresentation matrix Y1Transposing; f. ofp+1The vector of prediction data representing the p +1 th sampling instant, i.e. fp+1=[y(p+1)T y(p+2)T … y(p+f-1)T]TY (p +1) represents Y1 TColumn p +1, Y (p +2) represents Y1 TIn the p +2 th column, Y (p + f-1) represents Y1 TColumn p + f-1, M denotes the number of vectors of the history data vector and the prediction data vector constructed from n sets of observation data, M is n-p-f +1, n is 500, p is 10, f is 10, and M is 481.
(6) Obtaining a projection matrix Jq
(6.1) obtaining the unitary matrix V according to: h ═ U ∑ VTWherein V represents a unitary matrix constructed when singular value decomposition is performed on the matrix H,is represented by XpAnd XfThe constructed matrix Hankel matrix is used as a matrix,represents the sample covariance of the historical data vector,represents the sample covariance of the prediction data vector,representing the cross covariance of the historical data vector and the predicted data vector.
(6.2) obtaining the projection matrix J according to the following formulaq:Wherein, VqRepresenting a matrix constructed from the first q columns of the unitary matrix V,represents the Hankel matrix XpThe covariance matrix of (2).
(7) Obtaining process-perturbation joint model residuals for the kth window, k ═ 2,3, …, S +1
Acquiring a process-disturbance combined model residual error of the kth window by using the input and output data of the kth window acquired in the step (1): e.g. of the typek'(t)=yk'(t)-Gm,k'(q-1)uk'(t) wherein ek'(t) represents the process-perturbation joint model residual at the tth sampling instant of the kth' window, yk'(t) denotes the kth' window process output vector at the tth sampling instant uk'(t) represents the process input vector for the kth window at the tth sampling instant, Gm,k'(q-1) Representing the Process model, q, used by the EWMA batch controller in the Current operating regime-1A difference operator is represented.
(8) Construction of a Hankel matrix X according to the following formulap,k'And Xf,k'
Wherein the content of the first and second substances,process input vector, m, representing the kth windowuDenotes the number of input variables, mu=1, The process-perturbation joint model residual vector representing the kth window,process output vector, m, representing the kth windowyDenotes the number of output variables, my=1。
(8.2) constructing matrix Xk'And Yk':
Wherein u isi,k'The process input vector, u ", representing the k' th windowi,k'The process input vector representing the normalized k' th window, i.e.yj,k'Represents the process output vector, y ″, of the k' th windowj,k'The process output vector representing the normalized k' th window, i.e.ej,k'(t) Process-perturbation Joint model residual error, e, for the kth windowj,k'=(ej,k'(t)), ej,k'(t)=yj,k'(t)-(Gm,k′(q-1))juk'(t),yj,k'(t) denotes the jth process output, u, at the tth sampling instant in the kth windowk'(t) represents the column vector formed by all process inputs at the tth sampling instant in the kth window, (G)m,k′(q-1))jRepresents Gm,k′(q-1) Line j, e ″)j,k'Representing the process-perturbation combined model residual of the normalized k' th window, i.e.
(8.3) construction of Hankel matrix X according to the following formulap,k'And Xf,k':
Wherein p isp+1kRepresenting the historical data vector at the p +1 th sampling instant, i.e. pp+1,k'=[xk'(p)T … xk'(1)Tyk'(p)T … yk'(1)T]T,xk'(p) a representation matrixP column of (2), xk'(1) Representation matrixThe number 1. sup. st column of (a),representation matrix Xk'Transpose of (y)k'(p) a representation matrixP column, yk'(1) Representation matrixThe number 1. sup. st column of (a),representation matrix Yk'Transposing; f. ofp+1,k'Representing the vector of predicted data at the p +1 th sampling instant in the k' th window, i.e. fp+1,k'=[y(k')(p+1)Ty(k')(p+2)T … y(k')(p+f-1)T]T,y(k')(p +1) representsP +1 column, y(k')(p +2) representsP +2 column, y(k')(p + f-1) representsColumn p + f-1, M indicates the number of vectors of past and future data vectors constructed from n sets of observation data, M is n-p-f +1, n is 500, p is 10, f is 10, and M is 481.
(9) Obtaining a control performance monitoring index eta of an EWMA batch control systemCPIIndex (I)
Acquiring a control performance monitoring index eta of an EWMA batch control system according to the following formulaCPIIndexes are as follows:wherein the content of the first and second substances,represents the amount of control performance monitoring, J, of the EWMA batch-to-batch control system corresponding to the kth windowqRepresenting a projection matrix, pk,k'Representation matrix Xp,k'The k-th column of (1).
(10) Obtaining a reference condition model residual error
Using formulasObtaining a reference condition model residual error of the kth sampling moment of the kth window, wherein,representing the reference condition disturbance model estimated value y in the step (3.3)k'(t) represents the process output vector of the kth window at the tth sampling instant uk'(t) represents the process input vector for the kth window at the tth sampling instant, Gm,k'(q-1) Representing the process model used by the EWMA batch controller in the k' th window.
Using formulasObtaining the model mismatch/disturbance dynamic combined monitoring quantity, wherein,represents the model mismatch/disturbance dynamic joint monitoring quantity corresponding to the k' th window,has a value range of (0, 1)],εr(t) white noise estimate for the reference condition at the tth sampling time, cov (εr(t)) represents εrCovariance of (t), cov (v)r,k'(t)) represents vr,k'(t) covariance.
(12) Centralizing the closed-loop input and output data of the k' th window
And respectively carrying out centralized processing on the closed-loop input and the process output according to the following formula by utilizing the closed-loop input and output data of the kth window:wherein u'k'(t) represents the process input vector at the t-th sampling instant of the k' -th window after centering, uk'(t) represents the process input vector at the t-th sampling instant of the k' -th window that is not centered,mean vector, m, representing the process input at the t-th sampling instant of the k' -th windowuDenotes the number of input variables, m u1, t denotes the t-th sampling time, n denotes the number of samples of the k '-th window, and n is 500, y'k'(t) represents the process output vector, y, of the k' th window after centeringk'(t) represents the process output vector at the t-th sampling instant of the k' -th window that is not centered,mean vector, m, representing process output at the t-th sampling instantyRepresenting output variablesNumber, my=1。
(13) Obtaining the estimated value of white noise of actual working condition
Firstly, according to the process output y of the centralization processing obtained in the step (12)k′'(t) constructed data vector: y'P,k'(t)=[y′k'(t) … y′k'(t-P+1)](ii) a Then, by vector y'P,k'(t) constructed data matrix: y'P,k'(t)=[y′P,k'(t-1)T … y′P,k'(t-L)T]TWhere P denotes the data window size of the estimated white noise. Obtaining an estimated value epsilon of white noise of the reference working condition according to the following formulah,k'(t)=y′P,k'(t){I-Y′P,k'(t)T[Y′P,k'(t)Y′P,k'(t)T]-1Y′P,k'(t)}。
(14) Obtaining an estimated value of a disturbance model of an actual working condition
(14.1) obtaining an autoregressive moving average model of the out-of-band source input for the process output of the kth window according to:
wherein the content of the first and second substances,which is indicative of the delay factor, is,the coefficients of the auto-regressions are represented,the coefficient representing the input of the external source,coefficient representing moving average, Ik' represents the maximum order of autoregressive, Kk' represents the maximum order of exogenous input; j. the design is a squarek' indicating movementAverage maximum order;
(14.2) according to the self-adaptive minimum absolute value contraction and operator selection method, obtaining the coefficient vector and the order of the autoregressive moving average model input by the out-of-band source in the step (4.3):
Wk' denotes the window size of the sampled data,represents WkA data matrix of dimension' x 1,represents Wk'×(Ik'+Kk'+Jk') A dimensional data matrix;the method representing the adaptive minimum absolute value shrinkage and selection operator estimates the coefficient vector of the autoregressive moving average model, i.e. Coefficient, phi, representing the estimated autoregressive moving average modelk'A coefficient vector representing a real but unknown type of auto-regressive moving average, j-th coefficient phi in coefficients representing autoregressive moving average modelj,k'The weighting factor of (2).
(14.3) obtaining an estimated value of the actual working condition disturbance model according to the autoregressive moving average model of the out-of-band source input obtained in the step (13.2):wherein the content of the first and second substances,representing the coefficients of the auto-regressive part and the coefficients of the moving average part estimated in step (13.2),and representing the estimated value of the actual working condition disturbance model.
(15) Obtaining a model residual error of an actual working condition:
using formulasWherein the content of the first and second substances,representing the actual condition disturbance model estimated value, G, obtained by the step (14.3)m,k′(q-1) Representing the process model used by the EWMA batch controller in the k' th window.
(16) Obtaining interference characteristic monitoring quantity etaDVI
Using formulasObtaining interference characteristic monitoring quantityWherein epsilonh,k'(t) represents the white noise estimate for the actual condition at the tth sampling instant in the kth' window, | cov (εh,k'(t)) | denotes εh,k'(t) of the covariance matrixDeterminant, | cov (εr(t)) | denotes εr(t) determinant of covariance matrix.
(17) Obtaining a monitoring quantity eta of the disturbance modelDMI
Using formulasObtaining disturbance model monitoring quantity based on KL divergence Has a value range of (0, 1)]If, ifNear or equal to 1, the perturbation model is unchanged, vr,k'(t) reference condition model residual, v, at the tth sampling timeh,k'(t) represents the actual condition model residual at the t-th sampling instant in the k' -th window, J (f (v)r,k'(t)),g(vh,k'(t))) represents vh,k'(t) and vr,k'(t) KL divergence, expressed as:
wherein, f (v)r,k'(t)) represents v constructed using the nuclear density estimation methodr,k'(t) probability density function, f (v)h,k'(t)) represents v acquired by the kernel density estimation methodh,k'(t) probability density function, i ═ 1,2, …, Nf,NfRepresenting the total number of independent identically distributed sample points produced by the kernel density estimate.
(18) Obtaining model mismatch monitoring quantity etaPMI
Using formulasObtaining model mismatch monitoring quantityWherein epsilonh,k'(t) represents the white noise estimate of the actual condition at the t-th sampling instant in the k' -th window, vh,k'(t) represents the real-world model residual at the t-th sampling instant in the kth' window, | cov (εh,k'(t)) | denotes εh,k'Determinant of covariance matrix of (t), | cov (v)h,k'(t)) | denotes vh,k'(t) determinant of covariance matrix.
(19) Obtaining control limits of control performance monitoring quantity, model mismatch/disturbance dynamic monitoring quantity, interference characteristic monitoring quantity, disturbance model monitoring quantity and model mismatch monitoring quantity
(19.1) obtaining the control upper limit UP of the control performance monitoring amount according to the following formulaCPI:Wherein the content of the first and second substances,the control performance monitoring amount corresponding to the kth window is K ', K' is 2, 3.., S +1, h represents the kernel bandwidth, and K (·) represents the kernel density estimation with the kernel being a radial basis function.
(19.2) obtaining the control upper limit UP of the model mismatch/disturbance dynamic combined monitoring quantity according to the following formulaPDM: Wherein the content of the first and second substances,is the model mismatch/disturbance dynamic joint monitoring quantity corresponding to the k' th window.
(19.3) obtaining the control upper limit UP of the disturbance characteristic monitoring amount according to the following formulaDVAnd a lower control limit LPDV: Wherein the content of the first and second substances,is the interference characteristic monitoring quantity corresponding to the k' th window.
(19.4) obtaining the lower control limit LP of the disturbance model monitored quantity according to the following formulaDM: Wherein the content of the first and second substances,is the disturbance model monitoring quantity corresponding to the k' th window.
(19.5) obtaining the control upper limit UP of the model mismatch monitoring amount according to the following formulaPMI:Wherein the content of the first and second substances,is the interference characteristic monitoring quantity corresponding to the k' th window.
(20) Construction of Hankel matrix Xp,lAnd Xf,l
(20.1) acquiring N1 groups of input data and output data of the EWMA batch control system of the semiconductor process on line as actual working condition sample data, and dividing the actual working condition sample data into S1An online window, each window containing n groups of samples, wherein S1=N1-n+ 1。
(20.2) obtaining an online process-disturbance combined model residual according to the following formula:
el(t)=yl(t)-Gm,l(q-1)ul(t),
wherein e isl(t) represents the on-line process-perturbation joint model residual error at the tth sampling instant of the ith window, yl(t) represents the process output vector at the tth sampling instant of the ith window, ul(t) denotes the input vector at the tth sampling instant of the l-th window, t denotes the sampling instant, Gm(q-1) Representing a process model, q, used by the EWMA lot controller in the current operating regime-1Representing a difference operator,/=1,2,…,S1。
(20.3) acquiring a process input data set of the current working condition by using the process output vector, the process input vector and the process-disturbance combined model residual error which are acquired in real timeAnd output data set Yl 0:
Wherein the content of the first and second substances,representing an online process input vector, mu=1,Representing the on-line process-perturbation joint model residual vector,representing the on-line process output vector, my=1。
(20.4) constructing matrix X according tolAnd Yl:
Wherein u isi,lRepresents the process input vector, u ″, in the ith window of the online datai,lThe process input vector representing the normalized l-th window, i.e.yj,lRepresents the process output vector, y ″, of the ith window of online dataj,lThe process output vector representing the normalized l-th window, i.e.ej,lProcess-perturbation joint model residual vector representing the ith window of online data, ej,l=(ej,l(t)), ej,l(t)=yj,l(t)-(Gm,l(q-1))jul(t),(Gm,l(q-1))jProcess model G representing EWMA inter-batch controller usage in the ith window of online datam,l(q-1) J-th line of (1), yj,l(t) denotes the jth process output at the tth sampling instant of the ith window of online data, ul(t) represents the vector formed by all process inputs at the tth sampling time of the ith window of online data, e ″j,lRepresenting the normalized process-perturbation joint model residual,
(20.5) construction of Hankel matrix X according to the following formulap,lAnd Xf,l:
Wherein p isp+1,lRepresenting a history data vector at the p +1 th sampling instant in the ith window of line data, i.e. pp+1,l=[xl(p)T … xl(1)T yl(p)T … yl(1)T]T,xl(p) a representation matrixP column of (2), xl(1) Representation matrixThe p-th column of (2),representation matrix XlTranspose of (y)l(p) represents a matrix Yl TP column, yl(1) To representMatrix Yl TColumn 1, Yl TRepresentation matrix YlTransposing; f. ofp+1,lThe vector of predicted data representing the p +1 th sampling instant in the l window of line data, i.e. fp+1,l=[yl(p+1)T yl(p+2)T … yl(p+f-1)T]T,yl(p +1) represents Yl TP +1 column, yl(p +2) represents Yl TP +2 column, yl(p + f-1) represents Yl TColumn p + f-1, M indicates the number of vectors of past data vectors and future data vectors constructed from n sets of observation data, M is n-p-f +1, n is 500, p is 10, f is 10, and M is 481.
(21) Monitoring control performance of EWMA batch-to-batch control system
Obtaining the control performance monitoring quantity eta of the current working condition according to the following formula by utilizing the online dataCPI:Wherein the content of the first and second substances,indicating the control performance monitoring quantity, p, of the current operating mode corresponding to the ith windowk,lRepresentation matrix Xp,lThe kth column vector of (1).
According to the control upper limit UP of the control performance monitoring quantity obtained in the step (19.1)CPIJudgment ofWhether or not less than UPCPIIf, ifLess than UPCPIThen the system performance is better, ifGreater than UPCPIThe system performance is degraded.
(22) Preliminary diagnosis of factors leading to system performance degradation
(22.1) acquiring a reference working condition model residual error according to the following formula by using the online data:wherein v isr,l(t) represents the reference condition model residual error at the tth sampling time of the ith window of the online data,and representing the reference working condition disturbance model estimation value.
(22.2) obtaining the model mismatch/disturbance dynamic combined monitoring quantity eta according to the following formulaPDMI:Wherein the content of the first and second substances,has a value range of (0, 1)],vr,l(t) represents the reference condition model residual at the tth sampling instant, | cov (v)r,l(t)) | denotes vr,l(t) determinant of covariance matrix.
(22.3) calculating model mismatching/disturbance dynamic combined monitoring quantity eta by using online collected input data and output dataPDMIUpper control limit UP combined with model mismatch/disturbance dynamic joint monitoring quantityPDMIThe factors for controlling the performance degradation are preliminarily diagnosed if the current working condition is metGreater than UPPDMIIf the model mismatch or the external disturbance dynamics is changed, the system performance is reduced due to the model mismatch or the external disturbance dynamics; if the current operating condition isLess than UPPDMIThen changes in the controller parameters are a factor that causes degradation in system performance.
(23) Further diagnosis of factors leading to system performance degradation
(23.1) acquiring an estimated value epsilon of white noise of the actual working condition according to the steps (13) to (15) by utilizing the online datah,l(t), actual condition disturbance model estimation valueActual condition model residual vh,l(t)。
(23.2) obtaining the interference characteristic monitoring quantity eta of the on-line data according to the following formulaDVI:Wherein the content of the first and second substances,representing the interference characteristic monitoring quantity of the on-line data corresponding to the ith window, representing the change of white noise variance in actual working conditionr(t) represents the white noise estimation value of the reference condition at the t-th sampling moment, epsilonh,l(t) represents the white noise estimate for the actual condition at the tth sampling instant, | cov (εh,l(t)) | denotes εh,l(t) covariance matrix determinant, | cov (εr(t)) | denotes εr(t) covariance matrix determinant.
(23.3) calculating the actual working condition model residual error of the online data:wherein v ish,l(t) represents the model residual error of the online data actual condition corresponding to the ith window,on-line data actual condition disturbance model estimation value y representing ith windowl(t) an online data process output vector, u, at the tth sampling instant of the ith windowl(t) an online data process input vector, G, for the tth sampling instant of the l-th windowm,l(q-1) Represents the process model used by the EWMA batch controller in the ith window of the online data.
(23.4) obtaining the disturbance of the on-line data according to the following formulaModel monitoring quantity etaDMI:Wherein the content of the first and second substances,representing the monitored quantity, v, of the disturbance model corresponding to the l-th windowr,l(t) reference condition model residual, v, at the tth sampling timeh,l(t) represents the real model residual at the tth sampling instant, J (f (v)r,l(t)),g(vh,l(t))) represents vh,l(t) and vr,l(t) KL divergence.
(23.5) obtaining a model mismatch monitoring quantity eta of the on-line data according to the following formulaPMI:Wherein the content of the first and second substances,model mismatch monitoring quantity, epsilon, representing the on-line data corresponding to the ith windowh,l(t) the estimated value of the white noise of the actual working condition at the t-th sampling moment obtained in the step (23.1), vh,l(t) represents the actual condition model residual error, | cov (ε), of the t-th sampling time obtained in step (23.1)h,l(t)) | denotes εh,l(t) determinant of covariance matrix, | cov (v)h,l(t)) | denotes vh,l(t) determinant of covariance matrix.
(23.6) disturbance feature monitoring amount calculated using on-line dataMonitoring quantity of disturbance modelAmount of model mismatch monitoringLower control limit LP combined with disturbance characteristic monitoring quantityDVIControl of the amount of monitoring of the interference characteristicUpper limit UPDVILower control limit LP of disturbance model monitoring quantityDMIAnd upper control limit UP of model mismatch monitoring quantityPMIFurther diagnosing and identifying the factors causing the performance degradation of the EWMA batch-to-batch control system, and if the characteristic monitoring quantity is disturbedGreater than UPDVIOr less than LPDVIIf so, the white noise variance changes to cause the performance of the EWMA batch-to-batch control system to be reduced; if the model monitoring quantity is disturbedLess than LPDMIIf so, the performance of the EWMA batch control system is reduced due to the change of the external disturbance model; monitoring quantity if model mismatchingGreater than UPPMIThen the model mismatch causes the EWMA inter-batch control system performance to degrade.
In the reference operating mode, the control parameter of the controller is λ ═ 0.35, and the object model used in the controller: gm(q-1)=159.3q-1I.e., b is 159.3, the variance of white noise isThe present simulation will consider six cases shown in table 1:
TABLE 1 parameter settings
When a model mismatch occurs, fig. 3 shows the trend of the change in the control performance index and each diagnostic index. As can be seen from FIG. 3(a), the control performance indicator ηCPIExceeding the upper control limit from the 481 st sampling instant indicates a decrease in system performance, and therefore further diagnosis of the cause of system performance degradation is required. As can be seen from FIG. 4(b), η is after the 481-th sampling timingPDMIBeyond its upper control limit UPPDMIModel mismatch or perturbation dynamics changes are accounted for. By observing fig. 3(c) - (e), starting from the 481 th sampling timing, the interference characteristic monitoring amount ηDVIAnd the monitored quantity eta of the disturbance modelDMIAre all kept within the control interval, i.e. LPDVI<ηDVI<UPDVIAnd η DMI1, but the model mismatch monitor ηPMIBeyond its control limit, i.e. ηPMI>UPPMIThis shows that neither the disturbance signature (or white noise variance) nor the disturbance model of the EWMA batch-to-batch control system has changed, but the process model of the batch-to-batch control system does not match the actual process and results in a degradation of system performance. Therefore, the method of the present invention effectively evaluates system performance and identifies model mismatch from factors that control performance degradation.
Fig. 4 shows the variation tendency of the control performance index and each diagnostic index when the white noise variance of the external disturbance changes. As can be seen from FIG. 4(a), the control performance indicator ηCPIExceeding the upper control limit from the 481-th sampling instant indicates a decrease in system performance, and therefore further diagnosis of the cause of system performance degradation is required. As can be seen from FIG. 4(b), η is after the 481-th sampling timingPDMIBeyond its upper control limit UPPDMIModel mismatch or perturbation dynamics changes are illustrated. By observing fig. 4(c) - (e), the model mismatch monitor amount η starts from the 481 th sampling time instantPMIAnd the monitored quantity eta of the disturbance modelDMIAre all kept within a control region, i.e. ηPMI<UPPMIAnd η DMI1, but the interference characteristic monitoring quantity etaDVIBeyond its control line, i.e. etaDVI<LPDVIThis indicates that the process model and the actual process matching and disturbance model of the EWMA batch control system have not changed, but the disturbance signature (or white noise variance) has changed and resulted in a degradation of system performance. Thus, the method of the present invention effectively evaluates system performance and identifies changes in the interference signature (or white noise variance) from factors that control performance degradation.
FIG. 5 shows changes in control performance indicators and diagnostic indicators as controller parameters changeTrend. As can be seen from FIG. 5(a), the control performance indicator ηCPIExceeding the upper control limit from the 481-th sampling instant indicates a decrease in system performance, and therefore further diagnosis of the cause of system performance degradation is required. As can be seen from FIG. 5(b), η is after the 481-th sampling timingPDMIWithin its control limits, i.e. etaPDMI<UPPDMIAccounting for the controller parameter changes and resulting in a degradation of system performance. By observing fig. 5(c) - (e), the model mismatch monitor amount η starts from the 481 th sampling time instantPMIInterference characteristic monitoring quantity etaDVIMonitoring quantity eta of disturbance modelDMIAre all kept within a control region, i.e. ηPMI<UPPMI、 LPDVI<ηDVI<UPDVIAnd ηDMIThis indicates that the process model of the EWMA batch-to-batch control system matches the actual process, and neither the disturbance signature (or white noise variance) nor the disturbance model has changed. Thus, the method of the present invention effectively evaluates system performance and identifies changes in controller parameters from factors that control performance degradation.
Fig. 6 shows the variation tendency of the control performance index and each diagnostic index when the disturbance model is changed. As can be seen from FIG. 6(a), the control performance indicator ηCPIExceeding the upper control limit from the 481 st sampling instant indicates a decrease in system performance, and therefore further diagnosis of the cause of system performance degradation is required. As can be seen from FIG. 6(b), η is after the 481-th sampling timingPDMIBeyond its upper control limit UPPDMIModel mismatch or perturbation dynamics changes are accounted for. By observing fig. 6(c) - (e), the model mismatch monitor amount η starts from the 481 th sampling time instantPMIAnd interference characteristic monitoring quantity etaDVIAre all kept within a control region, i.e. ηPMI<UPPMIAnd LPDVI<ηDVI<UPDVIHowever, the disturbance model monitoring quantity etaDMIBeyond its control line, i.e. etaDMI<LPDMIThis indicates that the process model and actual process matching and disturbance characteristics (or white noise variance) of the EWMA batch-to-batch control system have not changed, but the disturbance model has changed and resulted in a system performanceAnd (5) reducing. Therefore, the method of the invention effectively evaluates the system performance and identifies the change of the disturbance model from the factors of control performance degradation.
Fig. 7 shows the trend of the change in the control performance index and each diagnostic index when the model mismatch and the white noise variance change occur simultaneously. As can be seen from FIG. 7(a), the control performance index ηCPIExceeding the upper control limit from the 481-th sampling instant indicates that the system performance is degraded, and therefore further diagnosis of the cause of system performance degradation is required. As can be seen from FIG. 7(b), η is after the 481-th sampling timingPDMIBeyond its upper control limit UPPDMIModel mismatch or perturbation dynamics changes are accounted for. By observing fig. 7(c) - (e), starting from the 481 th sampling timing, the interference characteristic monitored quantity ηDVIAnd model mismatch monitor ηPMIAre all changed, i.e. etaDVI<LPDVIAnd ηPMI>UPPMIHowever, the disturbance model monitoring quantity etaDMIStill within its control limits, i.e. ηDMIThis indicates that the disturbance model of the EWMA batch-to-batch control system has not changed, but the process model and the actual process mismatch and the disturbance signature (or white noise variance) have changed, and both have resulted in a degradation of the system performance. Thus, the method of the present invention effectively evaluates system performance and identifies interference signature changes and model mismatches from factors that control performance degradation.
When the models are mismatched and the disturbance model is changed, fig. 8 shows the variation tendency of the control performance index and each diagnostic index. As can be seen from FIG. 8(a), the control performance index ηCPIExceeding the upper control limit from the 481 st sampling instant indicates a decrease in system performance, and therefore further diagnosis of the cause of system performance degradation is required. As can be seen from FIG. 8(b), η is after the 481-th sampling timingPDMIBeyond its upper control limit UPPDMIModel mismatch or perturbation dynamics changes are accounted for. By observing fig. 8(c) - (e), starting from the 481 th sampling timing, the interference characteristic monitoring amount ηDVIAnd the monitored quantity eta of the disturbance modelDMIAre all changed, i.e. etaDVI<LPDVIAnd ηDMI<LPDMIBut the amount of model mismatch monitoring ηPMIStill within its control limits, i.e. etaPMI<UPPMIThis shows that the process model of the EWMA batch-to-batch control system matches the actual process, but both the disturbance signature (or white noise variance) and the disturbance model change, and both result in a degradation of the system performance. Thus, the method of the present invention effectively evaluates system performance and identifies changes in disturbance characteristics and disturbance models from factors that control performance degradation.
Through the analysis of the 1-6 and 6 fault conditions of the actual working conditions, the control performance diagnosis method of the semiconductor process batch control system based on the model residual error can be used for accurately diagnosing the factors of the system performance reduction.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A control performance diagnosis method of a semiconductor process batch control system is characterized by comprising the following steps:
s1, obtaining N groups of input data and output data of historical normal working conditions of the EWMA batch control system in the semiconductor manufacturing process as sample data, dividing the sample data into S +1 windows, and calculating a white noise estimation value epsilon of the reference working condition by using the input data and the output data of the first windowrAnd reference working condition disturbance model estimation valueObtaining process-disturbance combined model residual e (t), process data setAnd output data set Y1 0And based on the process data setObtaining a matrix X of reference conditions1From the output data set Y1 0Obtaining a matrix Y of reference conditions1Construction of Hankel matrix XpAnd XfAnd projection matrix Jq;
S2, constructing a process data set using the input data and the output data of the k' th windowAnd outputting the data setFrom a process data setObtaining matrix X of actual working conditionk'From the output data setObtaining matrix Y of actual working conditionsk'Obtaining the control performance monitoring quantity of the EWMA batch-to-batch control system corresponding to the kth window by adopting a typical variable analysis methodWherein k ═ 2,3, …, S + 1;
s3, according to the reference working condition disturbance model estimated value in the step S1Obtaining reference working condition model residual error v from input data and output data of k' th windowr,k'(t) and model mismatch/perturbation dynamics joint monitoring volume
S4, obtaining the actual working condition white noise estimation corresponding to the k 'th window by using the input data and the output data of the k' th windowValue epsilonh,k'(t) and actual condition disturbance model estimation valueAnd according to the actual working condition disturbance model estimated valueObtaining the residual error v of the actual working condition modelh,k'(t);
S5, according to the reference working condition white noise estimated value epsilon in the step S1rAnd the white noise estimate of the actual condition ε in step S4h,k'(t) calculating an interference characteristic monitoring quantityAccording to the reference working condition model residual v in the step S3r,k'(t) and the actual condition model residual v in step S4h,k'(t) calculating the amount of monitoring of the disturbance modelAccording to the actual working condition white noise estimated value epsilon in the step S4h,k'(t) and the actual condition model residual vh,k'(t) obtaining a model mismatch monitoring quantity
S6, respectively obtaining the control upper limit UP of the control performance monitoring quantity by adopting a kernel density estimation methodCPIUpper control limit UP of combined monitoring quantity of model mismatch/disturbance dynamicsPDMIUpper limit UP of control of the monitored quantity of interference characteristicsDVILower limit of control LP of disturbance characteristic monitoring amountDVILower control limit LP of disturbance model monitoring quantityDMIAnd the upper control limit UP of the model mismatch monitoring quantityPMI;
S7, collecting N1 groups of input data and output data of the EWMA batch control system of the semiconductor process on line, and obtaining the control performance monitoring quantity eta of the current working conditionCPIAccording to the control upper limit UP in step S6CPIJudging whether the control performance of the closed-loop system is reduced or not in real time;
s8, if the control performance monitoring quantity etaCPIControl upper limit UP greater than control performance monitoring amountCPIIf the performance of the EWMA batch control system is reduced, executing the step S9, otherwise, the EWMA batch control system has good performance;
s9, using the reference working condition disturbance model estimated value in the step S1The N1 groups of input data and output data in the step S7 acquire the model mismatch/disturbance dynamic combined monitoring quantity eta of the current working conditionPDMI;
S10, if the model mismatching/disturbance dynamic joint monitoring quantity etaPDMIControl upper limit UP larger than the model mismatch/disturbance dynamic joint monitoring amount in step S6PDMIIf the performance of the EWMA batch control system is reduced due to model mismatch or disturbance dynamics, executing the step S11, otherwise, the performance of the EWMA batch control system is reduced due to the change of the controller parameters;
s11, calculating the disturbance characteristic monitoring quantity eta of the current working conditionDVIMonitoring quantity eta of disturbance modelDMIAnd model mismatch monitor ηPMI(ii) a Disturbance characteristic monitoring quantity eta when current working conditionDVIGreater than the upper control limit UP of the disturbance characteristic monitoring amount in step S6DVIOr less than the lower control limit LP of the disturbance characteristic monitored quantityDVIWhen the interference characteristic changes, the performance of the EWMA batch control system is reduced; when the disturbance model monitors the quantity etaDMILower control limit LP less than disturbance model monitoring amountDMIMeanwhile, the performance of the EWMA batch control system is reduced due to the change of the disturbance model; when model mismatch monitor etaPMIControl upper limit UP greater than model mismatch monitoring amountPMIModel mismatch results in performance degradation of the EWMA batch-to-batch control system.
2. The method of claim 1, wherein the matrix X of baseline operating conditions is a matrix of run-to-run control systems1And Y1Respectively expressed as:
wherein u isiRepresents the ith process input vector, i 1, …, mu,muDenotes the number of input vectors, t denotes the sampling time, u ″iRepresenting the i-th process input vector after normalization, i.e. Means representing the ith process input vector, (σ)u,r)iRepresents the standard deviation of the ith process input vector; y isjRepresents the jth process output vector, j ═ 1, …, my,myIndicates the number of output vectors, y ″)jRepresenting the normalized jth process output vector, i.e. Means for representing the jth process output vector, (σ)y,r)jRepresents the standard deviation of the jth process output vector; e.g. of the typej(t) denotes the jth process-perturbation joint model residual vector, where ej=(ej(t)),ej(t)=yj(t)-(Gm(q-1))ju(t),(Gm(q-1))jRepresenting the process model G used in the first windowm(q-1) J-th line of (1), yj(t) representsthe jth process output at the sampling instant t, u (t) representing the column vector, e ″, formed by all the process inputs at the sampling instant t in the first windowjRepresents the normalized jth process-perturbation joint model residual vector, represents the mean of the jth process-perturbation combined model residual, (σ)e,r)jRepresenting the standard deviation of the jth process-perturbation combined model residual error;
the projection matrix JqComprises the following steps:
3. The method of claim 2, wherein the process data set is a process data setAnd outputting the data setRespectively expressed as:
wherein the content of the first and second substances,the process input vector representing the kth window,the process-perturbation joint model residual vector representing the kth window,a process output vector representing the kth window;
matrix X of the actual working conditionk'And Yk'Respectively expressed as:
wherein u isi,k'The process input vector, u ", representing the k' th windowi,k'The process input vector representing the normalized k' th window, i.e.yj,k'Represents the process output vector, y ″, of the k' th windowj,k'The process output vector representing the normalized k' th window, i.e.ej,k'Process-perturbation joint model residual vector representing the kth window, ej,k'=(ej,k'(t)),ej,k'(t)=yj,k'(t)-(Gm,k′(q-1))juk'(t),yj,k'(t) denotes the jth process output, u, at the tth sampling instant in the kth windowk'(t) represents the column vector formed by all process inputs at the tth sampling instant in the kth window, (G)m,k′(q-1))jRepresenting the Process model G used by the EWMA batch-to-batch controller in the k' th windowm,k′(q-1) Line j, e ″)j,k'Representing the process-perturbation combined model residual of the normalized k' th window, i.e.
Obtaining control performance monitoring quantity of EWMA batch control system by adopting typical variable analysis methodComprises the following steps:
4. The method as claimed in claim 1 or 3, wherein the model mismatch/disturbance dynamics joint monitoring isComprises the following steps:
wherein the content of the first and second substances,represents the model mismatch/disturbance dynamic joint monitoring quantity corresponding to the k' th window,has a value range of (0, 1)],εr(t) the white noise estimation value of the reference condition at the t-th sampling moment, vr,k'(t) represents the reference condition model residual at the t-th sampling instant in the kth' window, | cov (εr(t)) | denotes εrDeterminant of covariance matrix of (t), | cov (v)r,k'(t)) | denotes vr,k'(t) determinant of covariance matrix;
the reference working condition model residual vr,k'(t) is:
wherein v isr,k'(t) represents the reference condition model residual error corresponding to the k' th window,disturbance model estimation value representing reference working conditionInverse of (y)k'(t) represents the process output vector at the t-th sampling instant of the k' -th window, uk'(t) represents the process input vector at the t-th sampling instant in the k' -th window, Gm,k′(q-1) Representing the process model used by the EWMA batch controller in the k' th window.
5. The method of claim 4, wherein the actual process is performed in a batch control systemCondition model residual vh,k'(t) is:
wherein v ish,k'(t) represents the real model residual at the t-th sampling instant of the k' -th window,actual condition disturbance model estimation value representing k' th windowInverse of (y)k'(t) represents the process output vector at the t-th sampling instant of the k' -th window, uk'(t) represents the process input vector at the t-th sampling instant of the k' -th window, Gm,k′(q-1) Representing the process model used by the EWMA batch controller in the k' th window.
6. The method of claim 5, wherein the step S5 includes the steps of:
Wherein epsilonr(t) represents the white noise estimation value of the reference condition at the t-th sampling moment, epsilonh,k'(t) represents the white noise estimate for the actual condition at the t-th sampling instant in the kth' window, | cov (εh,k'(t)) | denotes εh,k'Determinant of covariance matrix of (t), | cov (εr(t)) | denotes εr(t) determinant of covariance matrix;
Wherein the content of the first and second substances,representing the monitored amount of the perturbation model for the k' th window,has a value range of (0, 1)]If, ifNear or equal to 1, the perturbation model is unchanged, vr,k'(t) represents the reference condition model residual at the t-th sampling instant in the k' -th window, vh,k'(t) represents the actual condition model residual at the t-th sampling instant in the k' -th window, J (f (v)r,k'(t)),g(vh,k'(t))) represents vh,k'(t) and vr,k'(t) KL divergence, expressed as:
wherein, f (v)r,k'(t)) represents v constructed using the nuclear density estimation methodr,k'(t) probability density function, f (v)h,k'(t)) represents v obtained by the nuclear density estimation methodh,k'(t) probability density function, i ═ 1,2, …, Nf,NfRepresenting the total number of independent identically distributed sample points resulting from the kernel density estimation;
Wherein epsilonh,k'(t) represents the white noise estimate of the actual condition at the t-th sampling instant in the k' -th window, vh,k'(t) represents the real-world model residual at the t-th sampling instant in the kth' window, | cov (εh,k'(t)) | denotes εh,k'Determinant of covariance matrix of (t), | cov (v)h,k'(t)) | denotes vh,k'(t) determinant of covariance matrix.
7. The method of claim 1 or 5, wherein the step S6 includes the steps of:
s6.1, calculating the control upper limit UP of the control performance monitoring quantityCPI:
Wherein the content of the first and second substances,the control performance monitoring quantity corresponding to the kth window is K ', K' is 2, 3.., S +1, h represents the kernel bandwidth, and K (·) represents the kernel density estimation with the kernel as a radial basis function;
s6.2, calculating the control upper limit UP of the model mismatch/disturbance dynamic combined monitoring quantityPDMI:
Wherein the content of the first and second substances,model mismatch/disturbance dynamic combined monitoring quantity corresponding to the kth' window;
s6.3, calculating the control upper limit UP of the interference characteristic monitoring quantityDVIAnd a lower control limit LPDVI:
Wherein the content of the first and second substances,is the interference characteristic monitoring quantity corresponding to the kth window;
s6.4, calculating a control lower limit LP of the monitoring quantity of the disturbance modelDMI:
Wherein the content of the first and second substances,is the disturbance model monitoring quantity corresponding to the kth window;
s6.5, calculating the control upper limit UP of the model mismatch monitoring quantityPMI:
8. The method of claim 2 or 3, wherein the step S7 includes the steps of:
s7.1, collecting the semiconductor system on lineTaking N1 groups of input data and output data of the batch control system of the EWMA as actual working condition sample data, and dividing the actual working condition sample data into S1An online window, each window containing n groups of samples, wherein S1=N1-n+1;
S7.2, calculating the residual error of the online process-disturbance combined model:
el(t)=yl(t)-Gm,l(q-1)ul(t),
wherein e isl(t) represents the on-line process-perturbation joint model residual error at the tth sampling instant of the ith window, yl(t) represents the process output vector at the tth sampling instant of the ith window, ul(t) denotes the input vector at the tth sampling instant of the l-th window, t denotes the sampling instant, Gm,l(q-1) Representing a Process model, q, used by an EWMA batch-to-batch controller in an on-line regime-1Denotes a difference operator, where l is 1,2, …, S1;
S7.3, acquiring a process input data set of the current working condition by using the process output vector, the process input vector and the process-disturbance combined model residual error which are acquired in real timeAnd output data set Y0 L:
Wherein the content of the first and second substances,representing the on-line process input vector and,representing the on-line process-perturbation joint model residual vector,representing an online process output vector;
s7.4, constructing a matrix XlAnd Yl:
Wherein u isi,lRepresents the process input vector, u ″, in the ith window of the online datai,lThe process input vector representing the normalized l-th window, i.e.yj,lRepresents the process output vector, y ″, of the ith window of online dataj,lThe process output vector representing the normalized l-th window, i.e.ej,lProcess-perturbation joint model residual vector representing the ith window of online data, ej,l=(ej,l(t)),ej,l(t)=yj,l(t)-(Gm,l(q-1))jul(t),(Gm,l(q-1))jProcess model G representing EWMA inter-batch controller usage in the ith window of online datam,l(q-1) J-th line of (1), yj,l(t) denotes the jth process output at the tth sampling instant of the ith window of online data, ul(t) represents the vector formed by all process inputs at the tth sampling time of the ith window of online data, e ″j,lRepresenting the normalized process-perturbation joint model residual,
s7.5, constructing a Hankel matrix Xp,lAnd Xf,l:
Wherein p isp+1,lRepresenting a history data vector at the p +1 th sampling instant in the ith window of line data, i.e. pp+1,l=[xl(p)T … xl(1)T yl(p)T … yl(1)T]T,xl(p) a representation matrixP column of (2), xl(1) Representation matrixThe p-th column of (2),representation matrix XlTranspose of (y)l(p) represents a matrix Yl TP column, yl(1) Representation matrix Yl TColumn 1, Yl TRepresentation matrix YlTransposing; f. ofp+1,lThe vector of predicted data representing the p +1 th sampling instant in the l window of line data, i.e. fp+1,l=[yl(p+1)T yl(p+2)T … yl(p+f-1)T]T,yl(p +1) represents Yl TP +1 column, yl(p +2) represents Yl TP +2 column, yl(p + f-1) represents Yl TP + f-1 column (b);
s7.6, acquiring control performance monitoring quantity eta of the current working condition by using online dataCPI:
Wherein the content of the first and second substances,indicating the control performance monitoring quantity, p, of the ith window of the on-line datak,lRepresentation matrix Xp,lThe kth column vector of (1);
9. The method of claim 5, wherein the step S9 includes the steps of:
s9.1, obtaining a reference working condition model residual error by using online data:
wherein v isr,l(t) reference for the sampling instant of the ith window of the on-line dataThe residual error of the working condition model,representing the reference condition disturbance model estimate, yl(t) an online data process output vector, u, at the tth sampling instant of the ith windowl(t) an online data process input vector at the tth sampling instant, G, for the ith windowm,l(q-1) Representing a process model used by the EWMA batch controller in the ith window of the online data;
s9.2, calculating model mismatching/disturbance dynamic combined monitoring quantity eta by utilizing online collected input data and output dataPDMI:
Wherein the content of the first and second substances,has a value range of (0, 1)],εr(t) represents the white noise estimate for the reference condition at the tth sampling instant, | cov (εr(t)) | denotes εr(t) determinant of covariance matrix, vr,l(t) represents the on-line data reference case model residual at the tth sampling instant of the ith window, | cov (v)r,l(t)) | denotes vr,l(t) determinant of covariance matrix;
s9.3, combining control upper limit UP of model mismatch/disturbance dynamic joint monitoring quantityPDMIThe factors for controlling the performance degradation are preliminarily diagnosed if the current working condition is metGreater than UPPDMIIf the model mismatch or the external disturbance dynamics is changed, the system performance is reduced due to the model mismatch or the external disturbance dynamics; if the current operating condition isLess than UPPDMIThen changes in the controller tuning parameters are a factor that causes degradation in system performance.
10. The method of claim 8, wherein the step S11 includes the steps of:
s11.1, calculating interference characteristic monitoring quantity eta of online dataDVI:
Wherein the content of the first and second substances,representing the interference characteristic monitoring quantity of the online data corresponding to the ith window,for characterizing the change of the white noise variance, ε, in the actual operating conditionsr(t) represents the white noise estimation value of the reference condition at the t-th sampling moment, epsilonh,l(t) represents the white noise estimation value of the actual working condition at the tth sampling moment of the ith window in the online monitoring stage, | cov (epsilon)h,l(t)) | denotes εh,lDeterminant of covariance matrix of (t), | cov (εr(t)) | denotes εr(t) determinant of covariance matrix;
s11.2, calculating the actual working condition model residual error of the online data:
wherein v ish,l(t) represents the model residual error of the online data actual condition corresponding to the ith window,on-line data real condition disturbance representing the ith windowDynamic model estimate, yl(t) an online data process output vector, u, at the tth sampling instant of the ith windowl(t) an online data process input vector at the tth sampling instant, G, for the ith windowm,l(q-1) Representing a process model used by the EWMA batch controller in the ith window of the online data;
s11.3, calculating disturbance model monitoring quantity eta of online dataDMI:
Wherein the content of the first and second substances,representing the monitored quantity, v, of the disturbance model corresponding to the l-th windowr,l(t) represents the on-line data reference condition model residual at the tth sampling instant of the ith window, vh,l(t) represents the on-line data real-time model residual error at the tth sampling time of the ith window, J (f (v)r,l(t)),g(vh,l(t))) represents vh,l(t) and vr,l(t) KL divergence;
s11.4, calculating model mismatch monitoring quantity eta of online dataPMI:
Wherein the content of the first and second substances,model mismatch monitoring quantity, epsilon, of the on-line data corresponding to the ith window of the on-line datah,l(t) represents the white noise estimate of the actual condition at the tth sampling time of the ith window of the on-line data, vh,l(t) represents the real model residual at the tth sampling instant of the l windows of online data, cov (εh,l(t)) represents εh,l(t) determinant of covariance matrix, cov (v)h,l(t)) represents vh,l(t) determinant of covariance matrix;
s11.5, combining the lower control limit LP of the interference characteristic monitoring quantityDVIUpper limit UP of control of the monitored quantity of interference characteristicsDVILower control limit LP of disturbance model monitoring quantityDMIAnd upper control limit UP of model mismatch monitoring quantityPMIFurther diagnosing and identifying the factors causing the performance degradation of the EWMA batch-to-batch control system and a plurality of disturbance characteristic monitoring quantitiesGreater than UPDVIOr less than LPDVIIf so, the white noise variance changes to cause the performance of the EWMA batch-to-batch control system to be reduced; if the model monitoring quantity is disturbedLess than LPDMIIf so, the performance of the EWMA batch control system is reduced due to the change of the external disturbance model; monitoring quantity if model mismatchingGreater than UPPMIThen the model mismatch causes the EWMA inter-batch control system performance to degrade.
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