Overlay method, device and equipment based on feed-forward compensation and medium

Abstract

The invention relates to the field of overlay calibration, in particular to an overlay method, device, equipment and medium based on feedforward compensation, and the method comprises the steps: obtaining a feedback compensation sub-prescription corresponding to a current layer in a previous batch, a previous layer overlay sub-prescription corresponding to the current layer, a current layer photoetching machine drift sub-prescription and a previous layer photoetching machine drift sub-prescription; combining the feedback compensation sub-prescription with the current-layer photoetching machine drift sub-prescription to obtain a current-layer feedback value; according to the current-layer photoetching machine drift sub-prescription and the previous-layer photoetching machine drift sub-prescription, determining a photoetching machine drift compensation value; determining a feed-forward value of the current layer according to the front layer alignment sub prescription and the drift compensation value of the photoetching machine; and according to the current layer feed-forward value and the current layer feedback value, current layer overlay pre-compensation is determined, and photoetching of the current layer is carried out according to the current layer overlay pre-compensation. According to the method, the difference between the two sub-prescriptions is used as a compensation item of a feed-forward value in traditional overlay, so that the overlay precision is greatly improved, and the yield of a final product is also improved.

Description

Technical Field

[0001] The present invention relates to the field of overlay calibration, and in particular to an overlay method, device, equipment and medium based on feedforward compensation. Background Art

[0002] With the advancement of semiconductor technology, process nodes are shrinking. In addition, with the introduction of complex lithography processes such as LELE and SADP, the requirements for product overlay are getting higher and higher.

[0003] In addition to the traditional APC system's feedforward and feedback compensation for low-order overlay, the current high-order overlay optimization of advanced node (28nm and below) products is mainly achieved through feedback (Feedback) or feedforward (Feedforward) of the high-order overlay sub-prescription (EEXY) to achieve high-order overlay compensation of the product.

[0004] The feedforward of the overlay recipe (EEXY Feedforward) can pre-compensate the product fingerprint of the process sheet on the previous layer to the current layer, so as to optimize the overlay and reduce the rework rate. However, the overlay accuracy and precision of the current feedforward overlay are still slightly insufficient, which means that the current feedforward overlay strategy still has room for improvement.

[0005] Therefore, how to further improve the overlay accuracy of the overlay method based on feedforward compensation and improve the yield of finished products has become an urgent problem to be solved by technical personnel in this field. Summary of the invention

[0006] The purpose of the present invention is to provide an overlay method, device, equipment and medium based on feedforward compensation to solve the problems of insufficient overlay accuracy and low finished product yield in the prior art.

[0007] In order to solve the above technical problems, the present invention provides an overlay method based on feedforward compensation, comprising:

[0008] Obtaining the feedback compensation sub-prescription corresponding to the previous batch of the current layer, the previous layer overlay sub-prescription corresponding to the current layer, the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription;

[0009] Combining the feedback compensation sub-prescription with the current layer lithography machine drift sub-prescription to obtain the current layer feedback value;

[0010] Determining a drift compensation value of a photolithography machine according to the drift sub-prescription of the current-layer photolithography machine and the drift sub-prescription of the previous-layer photolithography machine;

[0011] Determine the current layer feedforward value according to the previous layer overlay sub-prescription and the lithography machine drift compensation value;

[0012] According to the current layer feedforward value and the current layer feedback value, the current layer overlay pre-compensation is determined, and the current layer is photolithographically processed according to the current layer overlay pre-compensation.

[0013] Optionally, in the feedforward compensation-based overlay method, after the current layer is obtained by photolithography, the method further includes:

[0014] Scanning the current layer to obtain a feedback sub-prescription to be peeled off;

[0015] The feedback sub-prescription to be stripped is subtracted from the current layer feedforward value to obtain an updated calibration feedback compensation sub-prescription.

[0016] Optionally, in the feedforward compensation-based overlay method, the acquisition of the drift sub-prescription of the front-layer lithography machine includes:

[0017] Get the previous batch running time point;

[0018] According to the front-layer batch run time point, the corresponding front-layer lithography machine drift sub-prescription is obtained from the LCP server.

[0019] Optionally, in the overlay method based on feedforward compensation, determining the drift compensation value of the lithography machine according to the drift sub-prescription of the current layer lithography machine and the drift sub-prescription of the previous layer lithography machine includes:

[0020] The drift sub-prescription of the current-layer lithography machine is subtracted from the drift sub-prescription of the previous-layer lithography machine to determine the lithography machine drift compensation value.

[0021] An overlay device based on feedforward compensation, comprising:

[0022] An acquisition module, used to acquire the feedback compensation sub-prescription corresponding to the previous batch of the current layer, the previous layer overlay sub-prescription corresponding to the current layer, the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription;

[0023] A feedback module, used for combining the feedback compensation sub-prescription with the current layer lithography machine drift sub-prescription to obtain a current layer feedback value;

[0024] A drift module, used for determining a drift compensation value of a photolithography machine according to the drift sub-prescription of the current photolithography machine and the drift sub-prescription of the previous photolithography machine;

[0025] A feedforward module, used to determine the current layer feedforward value according to the previous layer overlay sub-prescription and the lithography machine drift compensation value;

[0026] The compensation lithography module is used to determine the overlay pre-compensation of the current layer according to the current layer feedforward value and the current layer feedback value, and perform lithography of the current layer according to the current layer overlay pre-compensation.

[0027] Optionally, in the overlay device based on feedforward compensation, the compensation lithography module further includes:

[0028] A scanning unit, used for scanning the current layer to obtain a feedback sub-prescription to be peeled off;

[0029] The calibration unit is used to make a difference between the feedback sub-prescription to be peeled off and the current layer feedforward value to obtain an updated calibration feedback compensation sub-prescription.

[0030] Optionally, in the feedforward compensation-based overlay device, the acquisition module includes:

[0031] Time point unit, used to obtain the previous batch time point;

[0032] The time corresponding acquisition unit is used to obtain the corresponding front-layer lithography machine drift sub-prescription from the LCP server according to the front-layer batch running time point.

[0033] Optionally, in the overlay device based on feedforward compensation, the drift module includes:

[0034] The subtraction module is used to subtract the drift sub-prescription of the current layer lithography machine from the drift sub-prescription of the previous layer lithography machine to determine the lithography machine drift compensation value.

[0035] An overlay device based on feedforward compensation, comprising:

[0036] Memory for storing computer programs;

[0037] A processor is used to implement the steps of any of the above-mentioned overlay methods based on feedforward compensation when executing the computer program.

[0038] A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of any of the above-described feedforward compensation-based overlay methods.

[0039] The overlay method based on feedforward compensation provided by the present invention obtains the feedback compensation sub-prescription corresponding to the previous batch of the current layer, the previous layer overlay sub-prescription corresponding to the current layer, the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription; the feedback compensation sub-prescription is combined with the current layer lithography machine drift sub-prescription to obtain the current layer feedback value; the lithography machine drift compensation value is determined according to the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription; the current layer feedforward value is determined according to the previous layer overlay sub-prescription and the lithography machine drift compensation value; the current layer overlay pre-compensation is determined according to the current layer feedforward value and the current layer feedback value, and the lithography of the current layer is performed according to the current layer overlay pre-compensation. After the lithography machine is measured and compared, its performance usually reaches the best. However, as the batch is continuously run, the horizontal performance of the lithography machine will drift, which is an error source that cannot be ignored in the overlay process. Therefore, the present invention uses historical records to capture the drift sub-prescription of the front-layer lithography machine during the front-layer lithography process and the drift sub-prescription of the current-layer lithography machine during the current-layer lithography process, and uses the difference between the two sub-prescriptions as the compensation item of the feedforward value in the traditional overlay, which greatly improves the overlay accuracy and thus improves the yield of the final product. The present invention also provides an overlay device, equipment and medium based on feedforward compensation with the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 A structural schematic diagram of a specific implementation of the overlay method based on feedforward compensation provided by the present invention;

[0042] Figure 2 A curve diagram showing the drift of a photolithography machine over time;

[0043] Figure 3 A structural schematic diagram of another specific implementation of the overlay method based on feedforward compensation provided by the present invention;

[0044] Figure 4 A schematic structural diagram of a specific implementation of the overlay device based on feedforward compensation provided by the present invention.

[0045] In the figure, it includes 100-acquisition module, 200-feedback module, 300-drift module, 400-feedforward module, and 500-compensation lithography module. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0047] The core of the present invention is to provide an overlay method based on feedforward compensation, and a flowchart of a specific implementation method thereof is shown as follows: Figure 1 As shown, it is called specific implementation mode 1, including:

[0048] S101: Obtain the feedback compensation sub-prescription corresponding to the previous batch of the current layer, the previous layer overlay sub-prescription corresponding to the current layer, the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription.

[0049] The current layer refers to the layer to be photolithographically processed, and the feedback compensation sub-prescription corresponding to the previous batch refers to the compensation sub-prescription fed back from the layer corresponding to the current layer in the previously produced chip. For example, if the batch in which the current layer is located is N, the previous batch may be any one of N-1, N-2, N-3…

[0050] The feedback compensation sub-prescription is obtained by scanning and measuring the lithography results of the corresponding layer of the previous batch, usually generated by GM (GridMapper) or LIS (Litho InSight), generally stored on the LCP (Litho Computing Platform) server, and can be obtained through time tags or exposure batch numbers.

[0051] Specifically, the acquisition of the drift sub-prescription of the front-layer lithography machine includes:

[0052] A1: Get the previous batch running time point.

[0053] A2: According to the front-layer batch run time point, the corresponding front-layer lithography machine drift sub-prescription is obtained from the LCP server.

[0054] like Figure 2As shown in the figure, after the lithography machine is calibrated and compensated in the horizontal direction, its performance usually reaches the best. At this moment, the characteristic horizontal morphology of the lithography machine is the baseline level (Baseline) of the lithography machine, which is obtained through the BMMO (Baseliner Matched Machine Overlay) test. As time goes by, the horizontal performance of the lithography machine will drift. For example, at T1 and T2, the performance of the lithography machine drifts to the positions of curves T1 and T2 respectively. The difference between it and the baseline, that is, the drift amount, can be obtained through BMMO measurement and recorded in the SBC (T1) and SBC (T2) lithography machine drift sub-prescription SBC (Scanner BaselineConstant) files. All historical sub-prescriptions will be stored in the LCP (Litho Computing Platform) server and can be obtained through time and other tags.

[0055] In this preferred embodiment, the drift situation of the lithography machine at the corresponding time is obtained from the LCP server through the batch running time point of the front layer, which is used as the drift sub-recipe of the lithography machine of the front layer.

[0056] S102: Combining the feedback compensation sub-recipe with the current layer lithography machine drift sub-recipe to obtain a current layer feedback value.

[0057] As mentioned above, the feedback compensation sub-prescription can be understood as the summary and feedback of the same layer as the current layer in the production history after the overlay is completed. The current layer lithography machine drift sub-prescription represents the lithography machine drift that occurs when the current layer is actually lithographically processed. The result of combining the two (which can be simply added) is used as the feedback value of the current layer.

[0058] S103: Determine a drift compensation value of the lithography machine according to the drift sub-recipe of the current lithography machine and the drift sub-recipe of the previous lithography machine.

[0059] This step specifically includes:

[0060] The drift sub-prescription of the current-layer lithography machine is subtracted from the drift sub-prescription of the previous-layer lithography machine to determine the lithography machine drift compensation value.

[0061] Under ideal conditions, the lithography machine will not deviate naturally. Therefore, in actual production, in order to improve the accuracy and precision of overlay, the drift degree of the lithography machine should not change when lithography is performed on the front layer and the current layer. Therefore, the drift sub-prescription of the current layer lithography machine should be subtracted from the drift sub-prescription of the front layer lithography machine to obtain the drift compensation value of the lithography machine.

[0062] Of course, according to actual conditions, other situations can be set for determining the drift compensation value of the lithography machine based on the drift sub-prescription of the current layer lithography machine and the drift sub-prescription of the previous layer lithography machine. For example, when the drift of the lithography machine is irregular, and the drift-time curves of the lithography machine in multiple historical records are different, cannot overlap, and have large differences, then the average value of the drift sub-prescription of the current layer lithography machine and the drift sub-prescription of the previous layer lithography machine can be used as the drift compensation value of the lithography machine.

[0063] S104: Determine the current layer feedforward value according to the previous layer overlay sub-prescription and the lithography machine drift compensation value.

[0064] The current layer feedforward value reflects the pre-lithography condition of the current layer, and includes not only the previous layer overlay sub-prescription reflecting the lithography condition of the previous layer, but also the lithography machine drift compensation value reflecting the lithography machine offset condition between the previous layer and the current layer in step S103.

[0065] S105: Determine the overlay pre-compensation of the current layer according to the current layer feedforward value and the current layer feedback value, and perform photolithography of the current layer according to the current layer overlay pre-compensation.

[0066] The current layer overlay precompensation may be a comprehensive sub-prescription obtained by calculating the current layer feedforward value and the current layer feedback value through LIS. Of course, it may also be obtained through other algorithms, which is not limited in this application.

[0067] The overlay method based on feedforward compensation provided by the present invention obtains the feedback compensation sub-prescription corresponding to the previous batch of the current layer, the previous layer overlay sub-prescription corresponding to the current layer, the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription; the feedback compensation sub-prescription is combined with the current layer lithography machine drift sub-prescription to obtain the current layer feedback value; the lithography machine drift compensation value is determined according to the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription; the current layer feedforward value is determined according to the previous layer overlay sub-prescription and the lithography machine drift compensation value; the current layer overlay pre-compensation is determined according to the current layer feedforward value and the current layer feedback value, and the lithography of the current layer is performed according to the current layer overlay pre-compensation. After the lithography machine is measured and compared, its performance usually reaches the best. However, as the overlay is carried out continuously, the horizontal performance of the lithography machine will drift. This is a source of error that cannot be ignored in the overlay process. Therefore, the present invention uses historical records to capture the drift sub-prescription of the previous layer lithography machine during the previous layer lithography during the overlay process, and the drift sub-prescription of the current layer lithography machine during the current layer lithography, and uses the difference between the two sub-prescriptions as the compensation item of the feedforward value in traditional overlay, which greatly improves the overlay accuracy and thus improves the yield of the final product.

[0068] On the basis of the first specific implementation mode, after each batch is completed, the feedback compensation sub-prescription is updated and corrected to obtain the second specific implementation mode, and its flow chart is as follows: Figure 3 As shown, including:

[0069] S201: Obtain the feedback compensation sub-prescription corresponding to the previous batch of the current layer, the previous layer overlay sub-prescription corresponding to the current layer, the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription.

[0070] S202: Combine the feedback compensation sub-recipe with the current layer lithography machine drift sub-recipe to obtain a current layer feedback value.

[0071] S203: Determine a drift compensation value of the lithography machine according to the drift sub-recipe of the current lithography machine and the drift sub-recipe of the previous lithography machine.

[0072] S204: Determine the feedforward value of the current layer according to the previous layer overlay sub-prescription and the lithography machine drift compensation value.

[0073] S205: Determine the overlay pre-compensation of the current layer according to the current layer feedforward value and the current layer feedback value, and perform photolithography of the current layer according to the current layer overlay pre-compensation.

[0074] S206: Scan the current layer to obtain a feedback sub-prescription to be peeled off.

[0075] S207: Subtract the feedback sub-prescription to be peeled from the current layer feedforward value to obtain an updated calibration feedback compensation sub-prescription.

[0076] The difference between this specific implementation and the above specific implementation is that, in this specific implementation, after the photolithography is completed, the feedback data used for subsequent batches is adjusted and improved, and the remaining steps are the same as the above specific implementation, which will not be elaborated here.

[0077] In the conventional overlay calibration, after the structure of the current layer is completed by lithography, the current layer completed by lithography needs to be scanned by a device, and the feedback compensation sub-prescription obtained by scanning can be used for feedback calibration of subsequent batches (equivalent to the "feedback compensation sub-prescription corresponding to the previous batch" in steps S101 and S201). In the present specific implementation, the feedback sub-prescription directly obtained by scanning (that is, the feedback sub-prescription to be stripped) will not be directly stored for subsequent feedback calibration. Since the "current layer" of each batch (assuming that there are three batches of chips "N-1, N, N+1", and the chips include a, b, c) is not directly stored, the feedback compensation sub-prescription obtained by scanning can be used for feedback calibration of subsequent batches. Three layers, assuming b is the target layer waiting for lithography, the "current layer" here refers to the b layer corresponding to each of the three batches) have different lithography environments (different offsets of the previous layer, different offsets of the lithography machine, etc.). Therefore, in this preferred implementation, after obtaining the feedback sub-prescription to be stripped, it will be further processed to remove the influence of the current layer feedforward value to obtain the updated calibration feedback compensation sub-prescription. When subsequent batches need to obtain the feedback compensation sub-prescription corresponding to this batch, they can directly obtain the feedback compensation sub-prescription corresponding to the previous batch, thereby further greatly improving the accuracy of subsequent batch overlay.

[0078] The following is an introduction to an overlay device based on feedforward compensation provided in an embodiment of the present invention. The overlay device based on feedforward compensation described below and the overlay method based on feedforward compensation described above can refer to each other.

[0079] Figure 4 The structural block diagram of the overlay device based on feedforward compensation provided by the embodiment of the present invention is shown in FIG. Figure 4 The overlay device based on feedforward compensation may include:

[0080] An acquisition module 100 is used to acquire a feedback compensation sub-prescription corresponding to the previous batch of the current layer, a previous layer overlay sub-prescription corresponding to the current layer, a current layer lithography machine drift sub-prescription, and a previous layer lithography machine drift sub-prescription;

[0081] Feedback module 200, used to combine the feedback compensation sub-prescription with the current layer lithography machine drift sub-prescription to obtain a current layer feedback value;

[0082] The drift module 300 is used to determine the drift compensation value of the lithography machine according to the drift sub-prescription of the current lithography machine and the drift sub-prescription of the previous lithography machine;

[0083] A feedforward module 400, for determining a current layer feedforward value according to the previous layer overlay sub-prescription and the lithography machine drift compensation value;

[0084] The compensation lithography module 500 is used to determine the overlay pre-compensation of the current layer according to the current layer feedforward value and the current layer feedback value, and perform lithography of the current layer according to the current layer overlay pre-compensation.

[0085] As a preferred implementation, the compensation overlay module 500 further includes:

[0086] A scanning unit, used for scanning the current layer to obtain a feedback sub-prescription to be peeled off;

[0087] The calibration unit is used to make a difference between the feedback sub-prescription to be peeled off and the current layer feedforward value to obtain an updated calibration feedback compensation sub-prescription.

[0088] As a preferred implementation, the acquisition module 100 includes:

[0089] Time point unit, used to obtain the previous batch time point;

[0090] The time corresponding acquisition unit is used to obtain the corresponding front-layer lithography machine drift sub-prescription from the LCP server according to the front-layer batch running time point.

[0091] As a preferred implementation, the drift module 300 includes:

[0092] The subtraction module is used to subtract the drift sub-prescription of the current layer lithography machine from the drift sub-prescription of the previous layer lithography machine to determine the lithography machine drift compensation value.

[0093] The overlay device based on feedforward compensation provided by the present invention is used to obtain the feedback compensation sub-prescription corresponding to the previous batch of the current layer, the previous layer overlay sub-prescription corresponding to the current layer, the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription through an acquisition module 100; a feedback module 200 is used to merge the feedback compensation sub-prescription with the current layer lithography machine drift sub-prescription to obtain the current layer feedback value; a drift module 300 is used to determine the lithography machine drift compensation value according to the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription; a feedforward module 400 is used to determine the current layer feedforward value according to the previous layer overlay sub-prescription and the lithography machine drift compensation value; a compensation lithography module 500 is used to determine the current layer overlay pre-compensation according to the current layer feedforward value and the current layer feedback value, and perform lithography of the current layer according to the current layer overlay pre-compensation. After the lithography machine is tested and compared, its performance usually reaches the best. However, as the batch is run continuously, the horizontal performance of the lithography machine will drift, which is a source of error that cannot be ignored in the overlay process. Therefore, the present invention uses historical records to capture the drift sub-prescription of the previous layer lithography machine during the previous layer lithography in the overlay process, and the drift sub-prescription of the current layer lithography machine during the current layer lithography, and uses the difference between the two sub-prescriptions as the compensation item of the feedforward value in traditional overlay, which greatly improves the overlay accuracy and thus improves the yield of the final product.

[0094] The feedforward compensation-based overlay device of this embodiment is used to implement the aforementioned feedforward compensation-based overlay method. Therefore, the specific implementation method of the feedforward compensation-based overlay device can be seen in the embodiment part of the feedforward compensation-based overlay method in the previous text. For example, the acquisition module 100, the feedback module 200, the drift module 300, the feedforward module 400, the compensation lithography module 500 are respectively used to implement the steps S101, S102, S103, S104 and S105 in the aforementioned feedforward compensation-based overlay method. Therefore, its specific implementation method can refer to the description of the corresponding embodiments of each part, which will not be repeated here.

[0095] The present invention also provides an overlay device based on feedforward compensation, comprising:

[0096] Memory for storing computer programs;

[0097] A processor is used to implement the steps of the overlay method based on feedforward compensation as described in any one of the above when executing the computer program. The overlay method based on feedforward compensation provided by the present invention obtains the feedback compensation sub-prescription corresponding to the previous batch of the current layer, the previous layer overlay sub-prescription corresponding to the current layer, the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription; the feedback compensation sub-prescription is combined with the current layer lithography machine drift sub-prescription to obtain the current layer feedback value; the lithography machine drift compensation value is determined according to the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription; the current layer feedforward value is determined according to the previous layer overlay sub-prescription and the lithography machine drift compensation value; the current layer overlay pre-compensation is determined according to the current layer feedforward value and the current layer feedback value, and the current layer lithography is performed according to the current layer overlay pre-compensation. After the lithography machine is tested and compared, its performance usually reaches the best. However, as the batch running continues, the horizontal performance of the lithography machine will drift, which is a source of error that cannot be ignored in the lithography process. Therefore, the present invention uses historical records to capture the drift sub-prescription of the previous layer lithography machine during the previous layer lithography during the overlay process, and the drift sub-prescription of the current layer lithography machine during the current layer lithography, and uses the difference between the two sub-prescriptions as the compensation item of the feedforward value in traditional overlay, which greatly improves the overlay accuracy and thus improves the yield of the final product.

[0098] The present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the overlay method based on feedforward compensation as described above are implemented. The overlay method based on feedforward compensation provided by the present invention obtains the feedback compensation sub-prescription corresponding to the previous batch of the current layer, the previous layer overlay sub-prescription corresponding to the current layer, the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription; the feedback compensation sub-prescription is combined with the current layer lithography machine drift sub-prescription to obtain the current layer feedback value; the lithography machine drift compensation value is determined according to the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription; the current layer feedforward value is determined according to the previous layer overlay sub-prescription and the lithography machine drift compensation value; the current layer overlay pre-compensation is determined according to the current layer feedforward value and the current layer feedback value, and the current layer lithography is performed according to the current layer overlay pre-compensation. After the lithography machine is measured and compared, its performance usually reaches the best. However, as the overlay is continuously carried out, the horizontal performance of the lithography machine will drift. This is a source of error that cannot be ignored in the lithography process. Therefore, the present invention uses historical records to capture the drift sub-prescription of the previous layer lithography machine during the previous layer lithography during the overlay process, and the drift sub-prescription of the current layer lithography machine during the current layer lithography, and uses the difference between the two sub-prescriptions as the compensation item of the feedforward value in traditional overlay, which greatly improves the overlay accuracy and thus improves the yield of the final product.

[0099] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0100] It should be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0101] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0102] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0103] The above is a detailed introduction to the overlay method, device, equipment and medium based on feedforward compensation provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. An overlay method based on feedforward compensation, characterized in that: include: Obtaining the feedback compensation sub-prescription corresponding to the previous batch of the current layer, the previous layer overlay sub-prescription corresponding to the current layer, the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription; Combining the feedback compensation sub-prescription with the current layer lithography machine drift sub-prescription to obtain the current layer feedback value; Determining a drift compensation value of a photolithography machine according to the drift sub-prescription of the current-layer photolithography machine and the drift sub-prescription of the previous-layer photolithography machine; Determine the current layer feedforward value according to the previous layer overlay sub-prescription and the lithography machine drift compensation value; According to the current layer feedforward value and the current layer feedback value, the current layer overlay pre-compensation is determined, and the current layer is photolithographically processed according to the current layer overlay pre-compensation.

2. The overlay method based on feedforward compensation according to claim 1, characterized in that: After the current layer is obtained by photolithography, the method further comprises: Scanning the current layer to obtain a feedback sub-prescription to be peeled off; The feedback sub-prescription to be stripped is subtracted from the current layer feedforward value to obtain an updated calibration feedback compensation sub-prescription.

3. The overlay method based on feedforward compensation as claimed in claim 1, characterized in that: The acquisition of the drift sub-prescription of the front-layer lithography machine includes: Get the previous batch running time point; According to the front-layer batch run time point, the corresponding front-layer lithography machine drift sub-prescription is obtained from the LCP server.

4. The overlay method based on feedforward compensation as claimed in claim 1, characterized in that: The step of determining the drift compensation value of the lithography machine according to the drift sub-prescription of the current lithography machine and the drift sub-prescription of the previous lithography machine comprises: The drift sub-prescription of the current-layer lithography machine is subtracted from the drift sub-prescription of the previous-layer lithography machine to determine the lithography machine drift compensation value.

5. An overlay device based on feedforward compensation, characterized in that: include: An acquisition module, used to acquire the feedback compensation sub-prescription corresponding to the previous batch of the current layer, the previous layer overlay sub-prescription corresponding to the current layer, the current layer lithography machine drift sub-prescription and the previous layer lithography machine drift sub-prescription; A feedback module, used for combining the feedback compensation sub-prescription with the current layer lithography machine drift sub-prescription to obtain a current layer feedback value; A drift module, used for determining a drift compensation value of a photolithography machine according to the drift sub-prescription of the current photolithography machine and the drift sub-prescription of the previous photolithography machine; A feedforward module, used to determine the current layer feedforward value according to the previous layer overlay sub-prescription and the lithography machine drift compensation value; The compensation lithography module is used to determine the overlay pre-compensation of the current layer according to the current layer feedforward value and the current layer feedback value, and perform lithography of the current layer according to the current layer overlay pre-compensation.

6. The overlay device based on feedforward compensation as claimed in claim 1, characterized in that: The compensation lithography module further includes: A scanning unit, used for scanning the current layer to obtain a feedback sub-prescription to be peeled off; The calibration unit is used to make a difference between the feedback sub-prescription to be peeled off and the current layer feedforward value to obtain an updated calibration feedback compensation sub-prescription.

7. The overlay device based on feedforward compensation as claimed in claim 1, characterized in that: The acquisition module comprises: Time point unit, used to obtain the previous batch time point; The time corresponding acquisition unit is used to obtain the corresponding front-layer lithography machine drift sub-prescription from the LCP server according to the front-layer batch running time point.

8. The overlay device based on feedforward compensation as claimed in claim 1, characterized in that: The drift module comprises: The subtraction module is used to subtract the drift sub-prescription of the current layer lithography machine from the drift sub-prescription of the previous layer lithography machine to determine the lithography machine drift compensation value.

9. An overlay device based on feedforward compensation, characterized in that: include: Memory for storing computer programs; A processor, configured to implement the steps of the overlay method based on feedforward compensation as described in any one of claims 1 to 4 when executing the computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the overlay method based on feedforward compensation as described in any one of claims 1 to 4 are implemented.

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