CN114690592A - Method for compensating alignment deviation - Google Patents

Abstract

A method of compensating for alignment deviation, comprising: acquiring alignment model deviation information according to the first alignment model and the second alignment model; and after the initial photoetching alignment is carried out on the initial second photoetching layer, carrying out compensation photoetching alignment on the initial second photoetching layer according to the alignment model deviation information so as to pattern the initial second photoetching layer and form a second photoetching layer. Therefore, in the photoetching process, the precision and the reliability of photoetching alignment are improved, and the stability of photoetching alignment is improved.

Description

Compensation method for misalignment

technical field

The invention relates to the field of semiconductor manufacturing, in particular to a compensation method for alignment deviation.

Background technique

Photolithography is a crucial technology in semiconductor fabrication, which can transfer patterns from the reticle to the surface of the silicon wafer to form semiconductor products that meet design requirements.

During the photolithography process, before exposure, first, the wafer needs to be aligned, that is, the alignment layer used for alignment in the wafer is aligned with the reticle.

In the process of wafer manufacturing, due to the influence of the manufacturing process, the wafer will be deformed. Therefore, the alignment mark of the alignment layer of the wafer will also change due to the influence of the deformation, resulting in the actual position of the alignment mark. Variety. Usually, in the process of aligning the wafer, an alignment model is used to compensate the alignment process of the wafer according to the detected position information of the alignment mark, so as to improve the alignment between the actual position of the alignment mark and the mask. accuracy.

In order to compensate the tiny deformation of the wafer and further improve the accuracy of lithography alignment, a Radial Base Function Alignment Model (RBF Alignment Model) is proposed. Due to the high compensation sensitivity of the RBF alignment model, sufficient alignment compensation can be made even for small deformations of the wafer.

However, when detecting the position information of the alignment marks, it is affected by some special process steps, such as some high temperature steps, planarization steps, etc., which may lead to false detection of the position information of the alignment marks, resulting in the detection of the alignment marks. There is a large deviation between the alignment mark position reflected by the position information and the actual alignment mark position. Since the compensation alignment is performed according to the RBF alignment model, the position information of the erroneous alignment marks is also compensated. Therefore, when a false detection occurs, when the compensation alignment is performed according to the RBF alignment model, a corresponding error compensation will be generated. This results in low lithography alignment accuracy and poor reliability, resulting in low overlay engraving accuracy.

SUMMARY OF THE INVENTION

The technical problem solved by the present invention is to provide a compensation method for alignment deviation, so as to improve the accuracy and reliability of lithography alignment and improve the stability of lithography alignment in the lithography process, so as to improve the overlay accuracy .

In order to solve the above technical problems, the technical solution of the present invention provides a compensation method for alignment deviation, which includes: providing a wafer to be compensated, the wafer to be compensated includes an initial first layer and is located on the initial first layer The initial first lithography layer of a photolithography layer to form a first photolithography layer; patterning the initial first layer according to the first photolithography layer to form a first layer; forming an initial second photolithography layer on the first layer; according to For the second alignment model, perform initial lithography alignment on the initial second lithography layer; obtain alignment model deviation information according to the first alignment model and the second alignment model; After the initial lithography alignment is performed on the initial second lithography layer, compensation lithography alignment is performed on the initial second lithography layer according to the alignment model deviation information, so as to pattern the initial second lithography layer, A second photolithographic layer is formed.

Optionally, the wafer to be compensated further includes: a first alignment layer, the initial first layer is located on the first alignment layer, and the initial first lithography layer is undergoing lithography alignment. On time, the first alignment layer is aligned.

Optionally, according to the first alignment model and the second alignment model, the method for obtaining alignment model deviation information includes: providing first preset alignment position information of the first alignment layer; The first preset alignment position information and the first alignment layer obtain the first detection alignment position information; according to the first detection alignment position information and the first alignment model, obtain the first alignment offset information; The first detection of the alignment position information and the second alignment model, to obtain the second alignment offset information; according to the first alignment offset information and the second alignment offset information, to obtain the alignment model deviation information .

Optionally, when performing lithography alignment on the initial first lithography layer according to the first alignment model, the first alignment offset information is acquired.

Optionally, when performing lithography alignment on the initial first lithography layer according to the first alignment model, the second alignment offset information is acquired.

Optionally, before the initial first lithography layer is patterned and the first lithography layer is formed, lithography alignment is performed on the initial first lithography layer according to the second alignment model to obtain all the the second alignment offset information.

Optionally, the first alignment layer includes a plurality of first alignment marks, and the first preset alignment position information includes preset position information of each of the first alignment marks; the first light The etching layer includes a plurality of first lithography alignment marks, and each of the first lithography alignment marks corresponds to one of the first alignment marks.

Optionally, the first alignment offset information includes several pieces of first offset information, and each first lithography alignment mark corresponds to one piece of first offset information; the second alignment offset information includes Several pieces of second offset information, each first lithography alignment mark also corresponds to one piece of second offset information; the alignment model deviation information includes: model offset information of each first lithography alignment mark , the model offset information is deviation information between a piece of first offset information and a piece of second offset information corresponding to the first lithography alignment mark.

Optionally, the method for acquiring first detection alignment position information includes: detecting each corresponding first alignment mark in the first alignment layer according to preset position information of each of the first alignment marks. position of the mark to obtain detection position information of each first alignment mark, where the first detection alignment position information includes detection position information of each of the first alignment marks.

Optionally, the method for obtaining the first offset information includes: according to the first alignment model, the preset position information of one first alignment mark, and the detection position information of the first alignment mark, obtaining and matching the first alignment mark. One piece of first offset information corresponding to one first lithography alignment mark corresponding to the first alignment mark.

Optionally, the method for obtaining the second offset information includes: according to the second alignment model, the preset position information of one first alignment mark, and the detection position information of the first alignment mark, obtaining the One piece of second offset information corresponding to the first lithography alignment mark corresponding to the first alignment mark.

Optionally, the method for compensating for lithography alignment further includes: providing an overlay deviation compensation model; before patterning the initial second lithography layer, further compensating the initial lithography deviation compensation model according to the overlay deviation compensation model. The two lithographic layers are aligned for compensation lithography.

Optionally, the method for compensating for lithography alignment further includes: providing an overlay deviation compensation model; acquiring a compensation alignment model according to the alignment model deviation information and the overlay deviation compensation model; The quasi-model performs compensatory lithographic alignment of the initial second lithographic layer.

Optionally, it further includes: before forming the initial second lithography layer, forming an initial second layer on the first layer; after forming the second lithography layer, according to the second lithography layer Layer patterning initializes the second layer to form the second layer.

Optionally, the method further includes: patterning the first layer according to the second photolithography layer to form a second layer.

Optionally, it further includes: providing a target overlay accuracy range of the second layer; providing a preset overlay accuracy range; providing an overlay safety factor X; providing n batches of wafers to be compensated, where n is a natural number; Obtain the overlay accuracy Y of the second layer of each wafer to be compensated in the kth batch to the k+ith batch in the n batches, where k is a natural number, i is a natural number, And k+i is within the range of n; when the target overlay accuracy range of the second layer is within the preset overlay accuracy range, and any (Y±X) target in the second layer When the overlay accuracy is within the range, obtain batch alignment model deviation information according to one of several alignment model deviation information of at least one batch in the first to k+i th batches; For the batch alignment model deviation information, compensation lithography is performed on the initial second lithography layer of the k+i+1 th batch of wafers to be compensated, so as to pattern the k+i+1 th lithography layer. The initial second photolithography layer of the wafers to be compensated for each batch is formed into the second photolithography layer of the wafer to be compensated for the k+i+1th batch.

Optionally, the first alignment model is a radial basis function alignment model.

Optionally, the second alignment model is a linear alignment model or a higher-order alignment model.

Compared with the prior art, the technical scheme of the present invention has the following beneficial effects:

In the compensation method for alignment deviation provided by the technical solution of the present invention, the second photolithography layer is used to form the second layer of the wafer to be compensated. Since the initial lithography alignment is performed on the initial first lithography layer according to the first alignment model, and the initial lithography alignment is performed on the initial second lithography layer according to the second alignment model, therefore, in In the process of forming the first layer and the second layer, different alignment models can be used according to different conditions of the wafer to be compensated. Therefore, by switching the alignment models, the alignment model in the lithography alignment is improved. For wafer suitability in different situations to improve the accuracy and reliability of lithography alignment. At the same time, since the alignment model deviation information is obtained according to the first alignment model and the second alignment model, and after the initial second lithography layer is lithographically aligned, according to the alignment model deviation information, and after performing initial lithography alignment on the initial second lithography layer, perform compensation lithography alignment on the initial second lithography layer according to the alignment model deviation information, therefore, in After the initial lithography alignment is performed on the initial second lithography layer, the model deviation between the first alignment model and the second alignment model can be compensated in the compensation lithography alignment, thereby improving the The stability of the lithography process between the first layer and the second layer is improved. In conclusion, through the alignment deviation compensation method, in the photolithography process, the accuracy and reliability of the photolithography alignment are improved, and the stability of the photolithography alignment is improved, so that the overetching of the wafer to be compensated is improved. High precision.

Further, since the target overlay accuracy range of the second layer is within the preset overlay accuracy range, and any (Y±X) is within the target overlay accuracy range of the second layer, therefore, The overlay accuracy of the second layer of the wafer to be compensated in the k+i th batch is highly stable. On this basis, according to the first batch to the k+ith batch, one of several alignment model deviation information of at least one batch is obtained, and the batch alignment model deviation information is obtained, and, According to the deviation information of the batch alignment model, perform compensation lithography alignment on the initial second lithography layer of the k+i+1th batch of wafers to be compensated, so as to pattern the k+i+th The initial second lithography layer of one batch of wafers to be compensated forms the second photolithography layer of the k+i+1 batch of wafers to be compensated. Alignment model deviation information (batch alignment model deviation information), instead of the alignment model deviation information corresponding to each wafer to be compensated in the k+i+1th batch, is used for the k+i+1th batch. Compensation lithography alignment is performed on the batches of wafers to be compensated, so that after the compensation lithography alignment is ensured, the overlay accuracy of the second lithography layer formed is relatively stable, which improves the accuracy of the k+i-th batch. The efficiency of the alignment deviation compensation of the wafers to be compensated for each batch of subsequent batches.

Description of drawings

FIG. 1 is a schematic flowchart of a compensation method for alignment deviation according to an embodiment of the present invention;

2 to 7 are schematic structural diagrams of steps in a method for compensating for alignment deviation according to an embodiment of the present invention.

Detailed ways

As described in the background art, when detecting the position information of the alignment marks, it is affected by some special process steps, such as some high temperature steps, planarization steps, etc., which may lead to false detection of the position information of the alignment marks, resulting in the detection of There is a large deviation between the alignment mark position reflected by the position information of the alignment mark and the actual alignment mark position. Since the compensation alignment is performed according to the RBF alignment model, the position information of the erroneous alignment marks is also compensated. Therefore, when a false detection occurs, when the compensation alignment is performed according to the RBF alignment model, a corresponding error compensation will be generated. This results in low lithography alignment accuracy and poor reliability, resulting in low overlay engraving accuracy.

In order to solve the above technical problems, the technical solution of the present invention provides a compensation method for alignment deviation, after performing initial photolithography alignment on the initial second photolithography layer, The second lithography layer performs compensation lithography alignment to pattern the initial second lithography layer to form the second lithography layer, thereby improving the lithography alignment accuracy and reliability of the wafer.

In order to make the above objects, features and beneficial effects of the present invention more clearly understood, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic flowchart of a compensation method for alignment deviation according to an embodiment of the present invention.

Referring to FIG. 1, the compensation method for the alignment deviation includes:

Step S100, providing a to-be-compensated wafer, the to-be-compensated wafer including an initial first layer and an initial first lithography layer on the initial first layer;

Step S110, providing a first alignment model and a second alignment model;

Step S120, performing lithography alignment on the initial first lithography layer according to the first alignment model, so as to pattern the initial first lithography layer to form a first lithography layer;

Step S130, patterning the initial first layer according to the first lithography layer to form a first layer;

Step S140, forming an initial second photolithography layer on the first layer;

Step S150, performing initial lithography alignment on the initial second lithography layer according to the second alignment model;

Step S160, obtaining alignment model deviation information according to the first alignment model and the second alignment model;

Step S170, after performing initial lithography alignment on the initial second lithography layer, perform compensation lithography alignment on the initial second lithography layer according to the alignment model deviation information to pattern the A second photolithography layer is initially formed to form a second photolithography layer.

Wherein, the second photolithography layer is used to form the second layer of the to-be-compensated wafer.

Since the initial lithography alignment is performed on the initial first lithography layer according to the first alignment model, and the initial lithography alignment is performed on the initial second lithography layer according to the second alignment model, therefore, in In the process of forming the first layer and the second layer, different alignment models can be used according to different conditions of the wafer to be compensated. Therefore, by switching the alignment models, the alignment model in the lithography alignment is improved. For wafer suitability in different situations to improve the accuracy and reliability of lithography alignment. At the same time, since the alignment model deviation information is obtained according to the first alignment model and the second alignment model, and after the initial second lithography layer is lithographically aligned, according to the alignment model deviation information, and after performing initial lithography alignment on the initial second lithography layer, perform compensation lithography alignment on the initial second lithography layer according to the alignment model deviation information, therefore, in After the initial lithography alignment is performed on the initial second lithography layer, the model deviation between the first alignment model and the second alignment model can be compensated in the compensation lithography alignment, thereby improving the The stability of the lithography process between the first layer and the second layer is improved. In conclusion, through the alignment deviation compensation method, in the photolithography process, the accuracy and reliability of the photolithography alignment are improved, and the stability of the photolithography alignment is improved, so that the overetching of the wafer to be compensated is improved. High precision.

It should be noted that the sequence between steps S130 to S150 and step S160 does not affect the technical effect of the embodiments of the present invention. Therefore, step S160 may be performed before, after, or between steps S130 to S150.

The following detailed description is given in conjunction with the accompanying drawings.

2 to 7 are schematic structural diagrams of steps in a method for compensating for alignment deviation according to an embodiment of the present invention.

Referring to FIG. 2 , a wafer to be compensated 200 is provided. The wafer to be compensated 200 includes an initial first layer 210 and an initial first photolithography layer 220 on the initial first layer 210 .

The initial first layer 210 is used for subsequent formation of the first layer.

The initial first lithography layer 220 is used for subsequent formation of the first lithography layer.

In this embodiment, the to-be-compensated wafer 200 further includes: a first alignment layer 110, the initial first layer 210 is located on the first alignment layer 110, and the subsequent initial first light The etching layer 220 is aligned with the first alignment layer 110 during photolithography alignment.

The first alignment layer 110 includes several first alignment marks (not shown), and each exposure shot includes one of the first alignment marks.

It should be noted that the exposure field refers to the area covered by one imaging of the lithography machine. In the process of fabricating integrated circuits on a wafer, for the convenience of process fabrication, the wafer is divided into several exposure fields as basic units in production, and the exposure fields are periodically repeated on the wafer.

Referring to FIG. 3, a first alignment model and a second alignment model are provided; the initial first lithography layer 220 is lithographically aligned according to the first alignment model to pattern the initial first lithography layer 220 to form a first photolithography layer 221 .

The method for performing photolithography alignment on the initial first photolithography layer 220 according to a first alignment model includes: providing first preset alignment position information of the first alignment layer 110; Suppose the alignment position information and the first alignment layer 110 obtain the first detection alignment position information; according to the first detection alignment position information and the first alignment model, obtain the first alignment offset information; according to the The first alignment offset information performs photolithography alignment on the initial first photolithography layer 220 .

Specifically, in this embodiment, the first alignment offset information is acquired when performing photolithography alignment on the initial first photolithography layer 220 according to a first alignment model.

The first preset alignment position information includes preset position information of each of the first alignment marks.

The method for acquiring first detection alignment position information includes: detecting the position of each corresponding first alignment mark in the first alignment layer 110 according to preset position information of each first alignment mark , to obtain detection position information of each first alignment mark, where the first detection alignment position information includes detection position information of each of the first alignment marks.

Specifically, in order to align the actual position of the first alignment mark in the subsequent lithography alignment, it is necessary to detect the actual position of each first alignment mark in order to align the lithography alignment mark. The standard process can be adjusted so that the subsequently formed photolithography layer can be aligned with the first alignment layer 110 to meet the design requirements.

The preset position information of the first alignment mark refers to preset information that can reflect the preset position of the first alignment mark. The detection position information of the first alignment mark refers to detection information that can reflect the actual position of the first alignment mark. It can be seen from this that there is correspondence between the preset position information of each first alignment mark and the detected position information.

It should be noted that, in order not to perform destructive detection on the wafer to be compensated, the actual position of the first alignment mark is usually detected by an optical method. Therefore, the detection information of the actual position of the first alignment mark is 1 through optical method. The detection information obtained by the signal, rather than the actual position of the first alignment mark. Due to the influence of some special process steps, such as some high temperature steps, planarization steps, etc., when the position information of the first alignment mark is detected, the detection position information of the first alignment mark has the risk of false detection, thus, When the false detection exists, the detected position of the first alignment mark reflected by the detected position information of the first alignment mark has a large deviation from the actual position of the first alignment mark.

In this embodiment, the first lithography layer 221 includes a plurality of first lithography alignment marks (not shown), each of the first lithography alignment marks and one of the first alignment marks correspond.

Specifically, when the initial first lithography layer 220 is lithographically aligned, a first layer mask (not shown) for exposure is provided. The pattern of the first layer mask includes several first mask alignment marks, and each first mask alignment mark corresponds to one first alignment mark. In the process of lithography alignment, by moving the wafer to be compensated or moving the first mask, the corresponding first mask alignment marks are aligned with the first alignment marks, so that after exposure and development, Several first lithography alignment marks are formed in the first lithography layer 221 , and each of the first lithography alignment marks corresponds to one of the first alignment marks.

In this embodiment, the first alignment offset information includes several pieces of first offset information, and each first lithography alignment mark corresponds to one piece of first offset information.

Specifically, in the process of lithography alignment, the alignment model calculates the offset information of each first mask alignment mark according to the detection position information of each first alignment mark, so that each Each of the first mask alignment marks is as close as possible to the corresponding first alignment marks, so as to realize the alignment between the corresponding first mask alignment marks and the first alignment marks.

The first alignment model and the second alignment model are different alignment models.

Specifically, in this embodiment, the first alignment model is a radial basis function alignment model. The second alignment model is a High Order Wafer Alignment Model (HOWA Model, High Order Wafer Alignment Model).

In one other embodiment, the second alignment model is a Linear AlignmentModel.

In yet another embodiment, the first alignment model is a higher-order alignment model or a linear alignment model, and the second alignment model is a radial basis function alignment model.

Since the first alignment model and the second alignment model are different alignment models, when the offset information of the first mask alignment mark is calculated according to the same first detection alignment information, different alignment models may be calculated. offset information, so that the first alignment model and the second alignment model respectively acquire different alignment offset information according to the first detected alignment information.

Wherein, the first alignment offset information is obtained according to the first alignment model and the first detection alignment information. In addition, in the first alignment offset information, each first offset information corresponds to one first mask alignment mark, so that each first lithography alignment mark corresponds to one first offset information correspond.

Specifically, the method for acquiring the first offset information includes: acquiring a first light beam corresponding to the first alignment mark according to the first alignment model and detection position information of a first alignment mark One piece of first offset information corresponding to the engraved alignment mark.

In this embodiment, the method for performing photolithography alignment on the initial first photolithography layer 220 further includes: providing an overlay deviation compensation model for the first layer; Before 220, photolithography alignment is also performed on the initial first photolithography layer 220 according to the overlay deviation compensation model of the first layer.

It should be noted that, the lithography alignment performed on the initial first lithography layer 220 may be performed separately according to the first alignment offset information and the overlay deviation compensation model of the first layer, and the actual lithography alignment is performed separately The action may also be to perform only one actual photolithography alignment action after obtaining parameters for photolithography alignment according to the first alignment offset information and the overlay deviation compensation model of the first layer.

Please continue to refer to FIG. 3 , and obtain alignment model deviation information according to the first alignment model and the second alignment model.

In this embodiment, according to the first alignment model and the second alignment model, the method for obtaining alignment model deviation information includes: providing first preset alignment position information of the first alignment layer 110; Obtain the first detection alignment position information according to the first preset alignment position information and the first alignment layer 110; obtain the first alignment bias according to the first detection alignment position information and the first alignment model according to the first detection alignment position information and the second alignment model, obtain second alignment offset information; according to the first alignment offset information and the second alignment offset information, obtain Quasi-model bias information.

The first preset alignment position information of the first alignment layer 110 is provided, the first detection alignment position information is acquired according to the first preset alignment position information and the first alignment layer 110, and the first detection alignment position information is obtained according to the The first detection of the alignment position information and the first alignment model and the acquisition of the first alignment offset information have already been described in the process of performing the photolithography alignment on the initial first photolithography layer 220 , and will not be repeated here.

In addition, since the first alignment model and the second alignment model obtain different alignment offset information according to the first detection alignment information, respectively, according to the first detection alignment position information and the first detection alignment information The second alignment model is obtained, and the second alignment offset information is obtained.

In this embodiment, before the initial first lithography layer 220 is patterned and the first lithography layer 221 is formed, lithography alignment is performed on the initial first lithography layer 220 according to the second alignment model alignment to obtain the second alignment offset information.

It should be noted that the performing lithography alignment on the initial first lithography layer 220 according to the second alignment model refers to performing lithography alignment on the initial first lithography layer 220 according to the second alignment model According to the quasi-position information, the offset information of the first mask alignment mark is calculated, that is, the real photolithography alignment operation is not performed.

The second alignment offset information includes several pieces of second offset information, and each first lithography alignment mark also corresponds to one piece of second offset information.

Similar to the first alignment offset information, in the second alignment offset information, each second offset information corresponds to one first mask alignment mark, so that each first lithography alignment The flag corresponds to one piece of second offset information.

And, similarly, the method for acquiring the second offset information includes: acquiring the first light corresponding to the first alignment mark according to the second alignment model and the detection position information of one first alignment mark One piece of second offset information corresponding to the engraved alignment mark.

In one other embodiment, the second alignment model is a linear alignment model, and the radial basis function alignment model is an alignment model that performs quadratic compensation on the basis of the linear alignment model. Therefore, When performing lithography alignment based on the radial basis function alignment model, the alignment offset information when performing lithography alignment based on the linear alignment model can be directly obtained. That is, in one other embodiment, when performing lithography alignment on the initial first lithography layer according to the first alignment model, second alignment offset information can also be obtained.

In this embodiment, the alignment model deviation information includes: model offset information of each first lithography alignment mark, and the model offset information is one corresponding to the first lithography alignment mark Difference information between the first offset information and one piece of second offset information.

The alignment model deviation information reflects the model deviation between the first alignment model and the second alignment model, that is, it reflects that the first alignment model and the second alignment model are detected according to the same first When aligning the information, the calculated deviation between the offset information of each first mask alignment mark.

Referring to FIG. 4 , the initial first layer 210 is patterned according to the first photolithography layer 221 to form the first layer 211 .

In this embodiment, after the first layer 211 is formed, the first photolithography layer 221 is removed.

Referring to FIG. 5 , an initial second layer 230 is formed on the first layer 211 ; after the initial second layer 230 is formed, an initial second photolithography layer 240 is formed on the initial second layer 230 .

The initial second photolithography layer 240 is used for the subsequent formation of the second photolithography layer, and the second photolithography layer is used for patterning the initial second layer 230 to form the second layer.

In other embodiments, the initial second layer is not formed. The second photolithographic layer is used to pattern the first layer to form the second layer.

Please continue to refer to FIG. 5 , according to the second alignment model, perform initial photolithography alignment on the initial second photolithography layer 240 .

Since the initial photolithography alignment is performed on the initial first photolithography layer 220 according to the first alignment model, and the initial photolithography alignment is performed on the initial second photolithography layer 240 according to the second alignment model, therefore , in the process of forming the first layer 211 and the second layer, different alignment models can be used according to the different conditions of the wafer to be compensated before and after the formation of the first layer 211, so that by switching the alignment model, In the lithography alignment, the applicability of each alignment model to the wafer under different conditions is improved, so as to improve the precision and reliability of the lithography alignment.

Specifically, when the detection position information of the first alignment mark has a small risk of false detection, the radial basis function alignment model can be used. The accuracy of lithographic alignment is better due to the high sensitivity of the radial basis function alignment model. After some special process steps, such as high temperature steps, planarization steps, etc., since the detection position information of the first alignment marks has a high risk of false detection, a high-order alignment model or a linear alignment model can be used. , in order to reduce the risk of erroneous compensation of the radial basis function alignment model in the lithography alignment, thereby improving the accuracy and reliability of the lithography alignment.

In this embodiment, in the initial photolithography alignment, the initial second photolithography layer 240 is aligned with the first alignment layer 110 .

In other embodiments, the wafer to be compensated further includes a second alignment layer, and in the initial photolithography alignment, the initial second photolithography layer is aligned with the second alignment layer.

Referring to FIG. 6 , after the initial photolithography alignment is performed on the initial second photolithography layer 240 , compensation photolithography alignment is performed on the initial second photolithography layer 240 according to the alignment model deviation information, so as to The initial second photoresist layer 240 is patterned to form a second photoresist layer 241 .

Since the deviation information of the alignment model is obtained according to the first alignment model and the second alignment model, and after the initial lithography alignment is performed on the initial second lithography layer 240, the alignment model is obtained according to the alignment model. The model deviation information performs compensation lithography alignment on the initial second lithography layer 240. Therefore, after the initial lithography alignment on the initial second lithography layer 240, the first alignment model and the second pair of The model deviation between the quasi-models can be compensated in the compensation lithography alignment, thereby improving the stability of the lithography process between the first layer 211 and the second layer.

It can be seen from the above that, through the compensation method for alignment deviation, in the lithography process, the precision and reliability of lithography alignment are improved, and the stability of lithography alignment is improved, so that the wafer to be compensated is improved. The overlay accuracy is high.

In this embodiment, the method for compensating lithography alignment further includes: providing an overlay deviation compensation model; obtaining a compensation alignment model according to the alignment model deviation information and the overlay deviation compensation model; The alignment model performs compensatory lithographic alignment on the initial second lithographic layer.

Specifically, in this embodiment, an overlay deviation compensation model for performing overlay deviation compensation on the second layer is also provided. Next, a total optimization model (compensation alignment model) is formed according to the alignment model deviation information and the overlay deviation compensation model, and after the initial lithography alignment, alignment is performed according to the compensation model The model performs compensation lithography alignment on the initial second lithography layer 240 .

Therefore, according to the compensation alignment model, not only the compensation of the overlay deviation is performed, but also the compensation of the model deviation is realized.

In other embodiments, the method for compensating for lithography alignment further comprises: providing an overlay deviation compensation model; before patterning the initial second lithography layer, further compensating the overlay deviation compensation model for the The initial second lithographic layer is subjected to compensation lithographic alignment. Specifically, in other embodiments, parameters for lithography alignment are respectively obtained according to the alignment model deviation information and the overlay deviation compensation model, and the lithography alignment is compensated according to the separately obtained parameters. It should be noted that the initial lithography alignment and the compensation lithography alignment may be actual lithography alignment actions performed separately, or may be based on the parameters used for the initial lithography alignment and the compensation lithography Alignment parameters, after obtaining the total parameters for lithography alignment, only one actual lithography alignment operation is performed.

In this embodiment, the first layer 211 includes several first layer alignment marks (not shown), each first layer alignment mark corresponds to one first alignment mark, and one first light The engraved alignment marks correspond. In order to meet the design requirements, the overlay accuracy between the second layer and the first layer 211 needs to be within a preset overlay accuracy range. Therefore, the first layer 211 and the first alignment layer 110 are also detected to obtain the alignment deviation information between the first layer 211 and the first alignment layer 110, the first layer 211 and the first alignment layer The alignment deviation information between 110 includes: several first alignment deviations, and one first alignment deviation is the position deviation information between the corresponding first layer alignment mark and the first alignment mark. In addition, after the initial lithography alignment, and before the compensation lithography alignment, according to the alignment deviation information between the first layer 211 and the first alignment layer 110, the The initial second lithography layer 240 is subjected to feed-forward compensation lithography alignment, so as to realize the alignment between the initial second lithography layer 240 and the first layer 211 .

It should be noted that the initial lithography alignment, the feedforward compensation lithography alignment and the compensation lithography alignment may be actual lithography alignment actions performed separately, or may be based on the Alignment parameters, parameters for feedforward compensation lithography alignment, and parameters for compensating lithography alignment, after obtaining the total parameters for lithography alignment, only one actual lithography alignment is performed action.

Referring to FIG. 7 , after the second photoresist layer 241 is formed, the initial second layer 230 is patterned according to the second photoresist layer 241 to form the second layer 231 .

In other embodiments, the initial second layer is not formed, and the first layer is patterned according to the second lithographic layer to form the second layer.

In another embodiment, the compensation method for the alignment deviation is also adjusted according to different batches of wafers to be compensated. Specifically, the compensation method for the alignment deviation further includes: providing a target overlay accuracy range of the second layer; providing a preset overlay accuracy range; providing an overlay safety factor X; Compensation wafer, n is a natural number; obtain the overlay accuracy Y of the second layer of each wafer to be compensated in the kth batch to the k+ith batch in the n batches, wherein, k is a natural number, i is a natural number, and k+i is within the range of n; when the target overlay precision range of the second layer is within the preset overlay precision range, and any (Y±X) When the target overlay accuracy of the second layer is within the range, obtain a batch according to one of several alignment model deviation information of at least one batch in the first to k+ith batches. Secondary alignment model deviation information; according to the batch alignment model deviation information, perform compensation lithography alignment on the initial second lithography layer of the k+i+1 th batch of wafers to be compensated for to pattern The initial second lithography layer of the k+i+1 th batch of wafers to be compensated forms the second lithography layer of the k+i+1 th batch of wafers to be compensated.

Since the target overlay accuracy range of the second layer is within the preset overlay accuracy range, and any (Y±X) is within the target overlay accuracy range of the second layer, the kth The overlay accuracy of the second layer of the +i batch of wafers to be compensated is highly stable. On this basis, according to the first batch to the k+i th batch, one of several alignment model deviation information of at least one batch is obtained, and the batch alignment model deviation information is obtained, and, According to the deviation information of the batch alignment model, perform compensation lithography alignment on the initial second lithography layer of the k+i+1th batch of wafers to be compensated, so as to pattern the k+i+th The initial second lithography layer of one batch of wafers to be compensated forms the second photolithography layer of the k+i+1 batch of wafers to be compensated. Alignment model deviation information (batch alignment model deviation information), instead of the alignment model deviation information corresponding to each wafer to be compensated in the k+i+1th batch, is used for the k+i+1th batch. Compensation lithography alignment is performed on the batches of wafers to be compensated, so that after the compensation lithography alignment is ensured, the overlay accuracy of the second lithography layer formed is relatively stable, which improves the accuracy of the k+i-th batch. The efficiency of the alignment deviation compensation of the wafers to be compensated for each batch of subsequent batches.

Specifically, in another embodiment, the batch alignment model deviation information may be a plurality of batches to be compensated in any one or more batches from the first batch to the k+ith batch. The average value of the alignment model deviation information for the wafer. Alternatively, the batch alignment model deviation information may also be among the alignment model deviation information of multiple wafers to be compensated for any one or more batches in the first to k+i th batches. 1 largest.

Although the present invention is disclosed above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be based on the scope defined by the claims.

Claims (18)

1. A method of compensating for misalignment, comprising:

providing a wafer to be compensated, wherein the wafer to be compensated comprises an initial first layer and an initial first photoetching layer positioned on the initial first layer;

providing a first alignment model and a second alignment model;

carrying out photoetching alignment on the initial first photoetching layer according to a first alignment model so as to pattern the initial first photoetching layer and form a first photoetching layer;

patterning the initial first layer according to the first lithography layer to form a first layer;

forming an initial second photolithographic layer on the first layer;

performing initial photoetching alignment on the initial second photoetching layer according to the second alignment model;

acquiring alignment model deviation information according to the first alignment model and the second alignment model;

and after carrying out initial photoetching alignment on the initial second photoetching layer, carrying out compensation photoetching alignment on the initial second photoetching layer according to the alignment model deviation information so as to pattern the initial second photoetching layer and form a second photoetching layer.

2. The method for compensating for alignment deviation as claimed in claim 1, wherein the wafer to be compensated further comprises: a first alignment layer, the initial first layer being on the first alignment layer and the initial first lithographic layer aligning the first alignment layer when performing lithographic alignment.

3. The method of compensating for misalignment of claim 2, wherein the method of obtaining the alignment model misalignment information based on the first alignment model and the second alignment model comprises: providing first preset alignment position information of the first alignment layer; acquiring first detection alignment position information according to the first preset alignment position information and a first alignment layer; acquiring first alignment offset information according to the first detection alignment position information and the first alignment model; acquiring second alignment offset information according to the first detection alignment position information and the second alignment model; and acquiring the deviation information of the alignment model according to the first alignment deviation information and the second alignment deviation information.

4. A method of compensating for alignment deviations as claimed in claim 3, characterized in that the first alignment deviation information is acquired while the initial first lithographic layer is being lithographically aligned according to a first alignment model.

5. A method of compensating for alignment deviation as claimed in claim 3, wherein said second alignment deviation information is obtained when lithographically aligning said initial first lithographic layer in accordance with said first alignment model.

6. A method of compensating for alignment misalignment as claimed in claim 3, wherein the initial first lithographic layer is lithographically aligned according to the second alignment model to obtain the second alignment offset information before being patterned to form the first lithographic layer.

7. The method of compensating for alignment deviation according to claim 3, wherein the first alignment layer includes a plurality of first alignment marks, and the first preset alignment position information includes preset position information of each of the first alignment marks; the first lithography layer comprises a plurality of first lithography alignment marks, and each first lithography alignment mark corresponds to 1 first alignment mark.

8. The method of compensating for alignment deviation of claim 7, wherein the first alignment deviation information includes a number of first deviation information, each first lithographic alignment mark corresponding to 1 first deviation information; the second alignment offset information comprises a plurality of second offset information, and each first photoetching alignment mark also corresponds to 1 second offset information; the alignment model bias information includes: and model offset information of each first lithography alignment mark, wherein the model offset information is deviation information between 1 first offset information and 1 second offset information corresponding to the first lithography alignment mark.

9. The method of compensating for an alignment deviation of claim 8, wherein the method of acquiring the first detected alignment position information comprises: detecting the position of each corresponding first alignment mark in the first alignment layer according to the preset position information of each first alignment mark to obtain the detection position information of each first alignment mark, wherein the first detection alignment position information comprises the detection position information of each first alignment mark.

10. The method of compensating for an alignment deviation according to claim 9, wherein the method of acquiring the first deviation information includes: and acquiring 1 piece of first offset information corresponding to 1 piece of first photoetching alignment mark corresponding to the first alignment mark according to the first alignment model, the preset position information of 1 piece of first alignment mark and the detection position information of the first alignment mark.

11. The method of compensating for an alignment deviation according to claim 9, wherein the method of acquiring the second deviation information includes: and acquiring 1 second offset information corresponding to the first photoetching alignment mark corresponding to the first alignment mark according to the second alignment model, the preset position information of 1 first alignment mark and the detection position information of the first alignment mark.

12. The method for compensating for alignment deviation as claimed in claim 1, wherein the method for compensating for lithographic alignment further comprises: providing an overlay deviation compensation model; before the initial second photoetching layer is patterned, carrying out compensation photoetching alignment on the initial second photoetching layer according to the overlay deviation compensation model.

13. The method for compensating for alignment deviation as claimed in claim 1, wherein the method for compensating for lithographic alignment further comprises: providing an overlay deviation compensation model; acquiring a compensation alignment model according to the alignment model deviation information and the overlay deviation compensation model; and performing compensation lithography alignment on the initial second lithography layer according to the compensation alignment model.

14. The method of compensating for an alignment deviation according to claim 1, further comprising: forming an initial second layer on the first layer prior to forming the initial second lithographic layer; after forming the second lithographic layer, patterning the initial second layer according to the second lithographic layer to form a second layer.

15. The alignment deviation compensation method according to claim 1, further comprising: patterning the first layer according to the second lithography layer to form a second layer.

16. The method of compensating for an alignment deviation according to claim 14 or 15, further comprising:

providing a target overlay accuracy range for the second layer; providing a preset alignment precision range; providing an overlay safety factor X; providing n batches of wafers to be compensated, wherein n is a natural number; acquiring the overlay accuracy Y of the second layer of each wafer to be compensated in the kth batch to the kth + i batch in the n batches, wherein k is a natural number, i is a natural number, and k + i is within the range of n; when the target overlay accuracy range of the second layer is within the preset overlay accuracy range and any (Y +/-X) is within the target overlay accuracy range of the second layer, acquiring batch alignment model deviation information according to 1 of a plurality of alignment model deviation information of at least 1 batch from the 1 st batch to the k + i batch; and performing compensation lithography alignment on the initial second lithography layers of the (k + i + 1) th batches of wafers to be compensated according to the batch alignment model deviation information to pattern the initial second lithography layers of the (k + i + 1) th batches of wafers to be compensated and form the second lithography layers of the (k + i + 1) th batches of wafers to be compensated.

17. The method for compensating for alignment deviation according to claim 1, wherein the first alignment model is a radial basis function alignment model.

18. The method of compensating for alignment deviation of claim 1, wherein the second alignment model is a linear alignment model or a higher order alignment model.

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