The present disclosure relates to an information processing apparatus and a storage medium.
An exposure apparatus can overlay the pattern of an original on a plurality of layers on a substrate and transfer it. To overlay the layers accurately, it is necessary to align each shot region of the substrate with the original. For example, an alignment mark arranged in each shot region on the substrate can be detected, and then the alignment can be performed based on position information of the alignment mark obtained by the detection and position information of the pattern of the original.
To implement accurate alignment, it is ideal to detect the alignment marks in all the shot regions on the substrate. However, this is not realistic from the viewpoint of productivity. Therefore, in general, a global alignment method is adopted to align all shot regions on a substrate and an original (see Japanese Patent Laid-Open Nos. 61-44429 and 62-84516).
In the global alignment method, it is assumed that the relative position of each of all shot regions on a substrate can be expressed by a function of the position coordinates of the shot region. Under this assumption, alignment marks only in some shot regions (sample shot regions) among the plurality of shot regions on the substrate are actually measured. Next, the parameters of the function model are estimated, using regression analysis-like statistic operation processing, from the assumed function model and the position measurement result. Using the estimated parameters and the function model, the position coordinates of each shot region on a stage coordinate system are calculated, thereby performing alignment. In the global alignment method, a polynomial model using stage coordinates as variables is used in general. Scaling that is a first-order polynomial of stage coordinates, rotation, uniform offset, and the like are mainly used (see Japanese Patent Laid-Open No. 6-349705).
There is also proposed a method using a regression model that considers, as a parameter, even a high-order component of the array of shot regions on the substrate (see Japanese Patent No. 3230271). Furthermore, there is proposed a method of measuring a plurality of sample points in advance, selecting a coefficient by a regression model having a regularization term and the data, and calculating position information of a shot region using the selected coefficient.
To perform accurate correction with a small number of sample shot regions (sample points), a method of accurately predicting (without overfitting) a high-order component of a substrate using a model of a high degree of freedom has been studied. This method can include, for example, creating, from a first regression model formed by a plurality of terms, a second regression model formed by some terms of the plurality of terms, and determining a plurality of sample shot regions using the second regression model.
However, to confirm the effect, it is currently necessary to calculate an overlay error by performing actual measurement using a parameter determined by prediction with respect to the created second regression model. Therefore, it is desired to readily predict, without performing such actual measurement, influence exerted when comparing parameters before and after prediction or adjusting a parameter.
The present disclosure provides a technique advantageous in readily confirming the effect of adjustment of a parameter associated with processing of determining sample shot regions.
The present invention in its aspect provides an information processing apparatus including a processor configured to determine, using a first regression model formed by a plurality of terms, a plurality of sample shot regions from a plurality of shot regions on a substrate, and a display controller configured to perform display control so that information of the plurality of sample shot regions determined by the processor is displayed on a user interface screen, wherein the processor is configured to redetermine a plurality of sample shot regions using a second regression model formed by some terms of the plurality of terms, and the display controller is configured to update display of the user interface screen so that information of the plurality of sample shot regions redetermined by the processor is displayed on the user interface screen.
Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).
Hereinafter, embodiments will be described in detail with reference to the attached drawings. Note, the following embodiments are not intended to limit the scope of the claimed invention. Multiple features are described in the embodiments, but limitation is not made to an invention that requires all such features, and multiple such features may be combined as appropriate. Furthermore, in the attached drawings, the same reference numerals are given to the same or similar configurations, and redundant description thereof is omitted.
As shown in
The controller CN is formed by, for example, a computer (information processing apparatus) including a CPU and a memory, and generally controls the units of the exposure apparatus 1 in accordance with a program stored in the storage unit SU or the like. In this embodiment, in addition to controlling exposure processing of exposing the substrate 4 via the original 2, the controller CN can function as a processor configured to obtain an array (a shot array or a region array) of a plurality of shot regions on the substrate (a plurality of regions on the substrate). On the display unit D, a user interface screen (UI screen) showing the setting, state, and the like of exposure processing is displayed. The controller CN can function as a display controller configured to control display of the UI screen.
The storage unit SU stores a program and various kinds of information (data) necessary to execute exposure processing of exposing the substrate 4 by controlling the units of the exposure apparatus 1. The storage unit SU also stores a program and various kinds of information (data) necessary for the controller CN to obtain the arrangement of the sample shot regions. Note that the controller CN, the storage unit SU, and the display unit D may be formed as external devices of the exposure apparatus 1. For example, an information processing apparatus including the controller CN, the storage unit SU, and the display unit D may be formed as a server apparatus configured to manage the exposure apparatus 1. Alternatively, an information processing apparatus including the controller CN, the storage unit SU, and the display unit D may be formed as a simulation apparatus configured to perform simulation for determining sample shot regions. An input device (a mouse, a keyboard, or the like) (not shown) operated by the user is also connected to the controller CN. Note that the storage unit SU may be a semiconductor memory, a disk such as a hard disk, or a memory in another form. A program for obtaining the arrangement of the sample shot regions may be stored in a computer-readable memory medium or may be provided to an information processing apparatus via a communication facility such as an electric communication network.
Light from the light source 8 is reflected by the beam splitter 9 and illuminates, via the lens 10, an alignment mark 11 or 12 provided on the substrate 4. The light diffracted by the alignment mark 11 or 12 is received by the sensor 14 via the lens 10, the beam splitter 9, and the lens 13.
Exposure processing by the exposure apparatus 1 will be described with reference to
In step S103, the controller CN executes fine alignment. More specifically, first, based on the result of pre-alignment, the controller CN drives the substrate stage 6 to a position where the alignment mark 12 for fine alignment provided on the substrate 4 can be detected by the alignment optical system 7. Then, the controller CN detects, using the alignment optical system 7, the alignment mark 12 provided in each of the plurality of shot regions on the substrate 4, thereby precisely obtaining the shift and the first-order linear component (magnification or rotation) of the entire substrate 4. At this time, the controller CN can also precisely obtain the high-order deformation component of the substrate 4 by obtaining the positions of a number of shot regions. This makes it possible to obtain the precise position of each shot region on the substrate 4, that is, the shot array.
In step S104, the controller CN exposes the substrate 4. More specifically, after the fine alignment is executed, the controller CN transfers the pattern of the original 2 to each shot region on the substrate 4 via the projection optical system 3. In step S105, the substrate 4 is unloaded from the exposure apparatus 1.
In this embodiment, if the substrate 4 is distorted, the high-order deformation component is corrected in the fine alignment of step S103. As a regression model used to estimate the shot array, a fifth-order polynomial model is used. However, the regression model is not limited to this. For example, as the regression model, an arbitrary order model can be used. A model (a triangle function model or a logarithmic model) other than a polynomial model may be used.
If the deformation of the substrate is expressed by a fifth-order polynomial model, the position deviations (ShiftX, ShiftY) of each shot region are represented by equations (1) below. Note that a position deviation of each shot region may be understood as a correction value used to correct the position deviation.
In the global alignment method, alignment measurement is executed in sample shot regions which are some of the plurality of shot regions on the substrate.
In the example shown in
After that, the controller CN determines the arrangement of the sample shot regions by a method using a regression model with respect to the provisionally determined arrangement of the sample shot regions. The decision method can include, for example, a first step of creating, from a first regression model formed by a plurality of terms, a second regression model formed by some terms of the plurality of terms, and a second step of determining the arrangement of the sample shot regions using the second regression model. The controller CN controls the UI screen 60 so that information of the determined arrangement of the sample shot regions is displayed on the wafer map display screen 62.
Furthermore, the controller CN controls the UI screen 60 so that the application status of the coefficient of each term forming the second regression model is displayed on the coefficient display screen 63. In this example, since the fifth-order polynomial model is assumed as the first regression model, the high-order correction coefficients k1 to k42 are displayed, on the coefficient display screen 63, as candidates to be applied. Then, among them, coefficients applied to the finally used regression model are identifiably displayed on the coefficient display screen 63. For example, in the example shown in
The number of sample points can be changed by a user operation. For example, when a mouse pointer overlaps the graph of the graph display screen 61, a partial region 101 including the position of the mouse pointer is displayed in a specific color by the rollover effect. If the mouse is clicked in this state, the number of sample points corresponding to the partial region 101 is set. In this way, the user can designate the number of sample shot regions. That is, in this embodiment, the graph display screen 61 is a designation screen used by the user to designate the number of sample shot regions.
The wafer map display screen 62 is a display screen that displays information of the position of each of the plurality of sample shot regions on the substrate. When the number of sample points is designated or changed, the controller CN redetermines the arrangement of the shot regions. After that, the controller CN updates the display so that the redetermined arrangement of the sample shot regions is displayed on the wafer map display screen 62. Furthermore, the controller CN updates the display so that the coefficients applied to the regression model when redetermining the arrangement of the sample shot regions are displayed on the coefficient display screen 63.
The correction residual for each shot region may be displayed on the wafer map display screen 62. For example, as shown in
In an example, the user can change the arrangement of the sample shot regions on the wafer map display screen 62 by operating the mouse and/or keyboard. For example, the user can move an arbitrary sample shot region to another region by dragging it using the mouse. If the arrangement of the sample shot regions is changed, the controller CN recalculates the correction residual, and updates the vector display of the correction residual of each shot region.
In an example, the user can change ON/OFF of each checkbox on the coefficient display screen 63 by operating the mouse and/or keyboard. That is, the coefficient display screen 63 is a selection screen for selecting some or all of the plurality of terms forming the regression model by user designation. This changes the application status of the coefficient of each term forming the second regression model. If ON/OFF of any of the checkboxes on the coefficient display screen 63 is changed, the controller CN recalculates the correction residual, and updates the vector display of the correction residual of each shot region. Referring to
A method of manufacturing an article according to the embodiment of the present disclosure is suitable for manufacturing an article, for example, a microdevice such as a semiconductor device or an element having a fine structure. The method of manufacturing an article according to the embodiment includes a step of forming, using the above-described exposure apparatus, a latent image pattern on a photosensitive agent applied on a substrate (a step of exposing the substrate), and a step of developing the substrate on which the latent image pattern has been formed in the above step. In addition, the manufacturing method includes other well-known steps (oxidation, film formation, deposition, doping, planarization, etching, resist removal, dicing, bonding, packaging, and the like). The method of manufacturing an article according to this embodiment is more advantageous than the conventional methods in at least one of the performance, quality, productivity, and production cost of the article.
Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2023-030132, filed Feb. 28, 2023, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
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2023-030132 | Feb 2023 | JP | national |