Method and device for compensating overlay error of photoetching process and photoetching machine

Abstract

The invention discloses a photoetching process overlay error compensation method, a photoetching process overlay error compensation device and a photoetching machine, which can be used in the field of semiconductor manufacturing, and the method comprises the following steps: firstly, obtaining overlay error distribution data; then, based on the overlay error distribution data, a target compensation scheme is obtained through a pre-established compensation model; the target compensation scheme comprises a target stress compensation scheme and a target local thermal compensation scheme; and finally, driving a stress actuator to apply compensation stress to the mask plate based on the target stress compensation scheme. And driving a thermal compensation device to apply a compensation thermal dose to the mask based on the target local thermal compensation scheme. Therefore, through the pre-established compensation model, the compensation stress and the compensation heat dose required for compensating the overlay error are reversely obtained according to the overlay error distribution data, and the mask plate is deformed by applying the compensation stress and the compensation heat dose to the mask plate, so that the overlay error of a photoetching process can be effectively reduced, the reliability and the yield of a product are improved, and the yield of the product is improved. And the large-scale production cost is reduced.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a method, device and lithography machine for compensating overlay errors in a lithography process. Background Art

[0002] With the development of semiconductor technology, the integration of chips has been significantly improved, and the requirements for overlay errors in the photolithography process have become increasingly stringent.

[0003] In semiconductor manufacturing, overlay error refers to the difference between each layer of circuits, which can be quantitatively described as the coordinate deviation between the lithography pattern and the reference pattern in the X and Y directions. Traditional projection lithography systems rely on optical lenses to compensate for overlay errors. However, as technology nodes shrink, this compensation capability is gradually approaching its limit and it is difficult to meet current requirements for lithography quality.

[0004] Therefore, how to reduce the overlay error of the photolithography process becomes a problem that needs to be solved. Summary of the invention

[0005] Based on the above problems, the present application provides a method, device and lithography machine for compensating overlay error in a lithography process, which can reduce the overlay error in the lithography process.

[0006] The embodiments of the present application disclose the following technical solutions:

[0007] In a first aspect, an embodiment of the present application provides a method for compensating overlay errors in a lithography process, the method comprising:

[0008] Acquire overlay error distribution data; the overlay error distribution data includes an offset value between the lithographic pattern at each acquisition point and a reference pattern;

[0009] Based on the overlay error distribution data, a target compensation scheme is obtained through a pre-established compensation model; the compensation model is established based on the correlation between the overlay error distribution data, the compensation scheme and the compensation parameters; the target compensation scheme includes a target stress compensation scheme and a target local thermal compensation scheme;

[0010] Based on the target stress compensation scheme, a stress actuator is driven to apply compensation stress to the mask; based on the target local thermal compensation scheme, a thermal compensation device is driven to apply compensation thermal dose to the mask.

[0011] Optionally, the compensation model is established by the following method:

[0012] Acquire the overlay error distribution data, the in-field coordinates of the exposure field corresponding to each acquisition point, the first correlation relationship between the compensation parameters, and a plurality of optional compensation schemes;

[0013] Based on the first association relationship, simulating the multiple optional compensation schemes through a simulation model to establish a second association relationship between the compensation schemes and the compensation parameters;

[0014] A compensation model is established based on the first association relationship and the second association relationship.

[0015] Optionally, before simulating the plurality of optional compensation schemes through a simulation model based on the first association relationship and establishing a second association relationship between the compensation schemes and compensation parameters, the method further includes:

[0016] A simulation model is established based on the physical parameters of the mask, the stress around the mask and the local thermal dose input; the simulation model is used to predict the deformation and displacement information of the mask pattern under different stress and local thermal dose input conditions.

[0017] Optionally, after driving the stress actuator to apply compensating stress to the mask based on the target stress compensation scheme; and driving the thermal compensation device to apply compensating thermal dose to the mask based on the target local thermal compensation scheme, the method further comprises:

[0018] Acquire actual residual distribution data and theoretical residual distribution data; the residual distribution data is overlay error distribution data after overlay error compensation;

[0019] A residual error is calculated based on the actual residual distribution data and the theoretical residual distribution data.

[0020] Optionally, after driving the stress actuator to apply compensating stress to the mask based on the target stress compensation scheme; and driving the thermal compensation device to apply compensating thermal dose to the mask based on the target local thermal compensation scheme, the method further comprises:

[0021] Monitoring actual residual distribution data; the actual residual distribution data includes an offset value between the lithographic pattern and the reference pattern at each acquisition point;

[0022] Based on the actual residual distribution data, the absolute average value of the offset value of each acquisition point and the sum of three times the standard deviation are calculated to obtain first data;

[0023] If the first data is greater than the preset threshold value for more than the preset number of consecutive times, an alarm message is output.

[0024] Optionally, after obtaining a target compensation solution based on the overlay error distribution data through a pre-established compensation model, the method further includes:

[0025] Obtaining the theoretical displacement deviation of each acquisition point after applying the target compensation scheme;

[0026] Based on the theoretical displacement deviation of each acquisition point, an error compensation vector diagram is obtained.

[0027] In a second aspect, an embodiment of the present application provides a device for compensating overlay errors in a photolithography process, the device comprising: an acquisition module, a scheme determination module and a driving module;

[0028] The acquisition module is used to acquire overlay error distribution data; the overlay error distribution data includes an offset value between the lithographic pattern at each acquisition point and the reference pattern;

[0029] The scheme determination module is used to obtain a target compensation scheme based on the overlay error distribution data through a pre-established compensation model; the compensation model is established based on the correlation between the overlay error distribution data, the compensation scheme and the compensation parameters; the target compensation scheme includes a target stress compensation scheme and a target local thermal compensation scheme;

[0030] The driving module is used to drive the stress actuator to apply compensation stress to the mask based on the target stress compensation scheme; and drive the thermal compensation device to apply compensation thermal dose to the mask based on the target local thermal compensation scheme.

[0031] In a third aspect, an embodiment of the present application provides a lithography machine, the lithography machine comprising: a controller, a stress actuator, and a thermal compensation device;

[0032] The controller is electrically connected to the stress actuator and the thermal compensation device;

[0033] The controller is used to drive the stress actuator to execute a target stress compensation scheme and drive the thermal compensation device to execute a target local thermal compensation scheme according to the steps of compensating for overlay errors in the lithography process described in any embodiment of the first aspect.

[0034] Optionally, the lithography machine includes 16 stress actuators; the stress actuators are symmetrically arranged around the mask; and every 4 stress actuators are arranged on the same side of the mask.

[0035] Optionally, the thermal compensation device includes a plurality of micro heaters and micro coolers.

[0036] Compared with the prior art, this application has the following beneficial effects:

[0037] The present application provides a method for compensating overlay errors in a photolithography process. In the method, first, overlay error distribution data is obtained; the overlay error distribution data includes the offset value between the photolithography pattern and the reference pattern at each acquisition point; then, based on the overlay error distribution data, a target compensation scheme is obtained through a pre-established compensation model; the compensation model is established based on the correlation between the overlay error distribution data, the compensation scheme and the compensation parameters; the target compensation scheme includes a target stress compensation scheme and a target local thermal compensation scheme; finally, based on the target stress compensation scheme, a stress actuator is driven to apply compensation stress to the mask; based on the target local thermal compensation scheme, a thermal compensation device is driven to apply a compensation thermal dose to the mask. Thus, through the pre-established compensation model, the compensation stress and compensation thermal dose required to compensate for the overlay error are reversely obtained according to the overlay error distribution data, and then the mask is deformed by applying the compensation stress and compensation thermal dose to the mask, thereby realizing compensation for the overlay error in the photolithography process, which can effectively reduce the overlay error of the photolithography process, improve the reliability and yield of the product, and reduce the cost of large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A flow chart of a method for compensating overlay errors in a photolithography process provided in an embodiment of the present application;

[0040] Figure 2 A flow chart of a method for establishing a compensation model provided in an embodiment of the present application;

[0041] Figure 3 A schematic diagram of stress around a mask and local thermal dose input provided in an embodiment of the present application;

[0042] Figure 4 A compensation parameter distribution diagram provided in an embodiment of the present application;

[0043] Figure 5 An overlay error distribution vector diagram provided in an embodiment of the present application;

[0044] Figure 6 An error compensation distribution vector diagram provided in an embodiment of the present application;

[0045] Figure 7 An overlay residual distribution vector diagram provided in an embodiment of the present application;

[0046] Figure 8 A residual error distribution diagram provided in an embodiment of the present application;

[0047] Fig. 9 A compensation effect analysis diagram provided in an embodiment of the present application;

[0048] Fig.10 A schematic diagram of a photolithography process overlay error compensation device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The method, device and lithography machine for compensating overlay errors in a lithography process provided in the present application can be used in the field of semiconductor manufacturing. The above is only an example and does not limit the application field of the method, device and lithography machine for compensating overlay errors in a lithography process provided in the present application.

[0050] The terms "first", "second", "third" and "fourth" etc. in the specification, claims and drawings of this application are used to distinguish different objects rather than to limit a specific order.

[0051] In the embodiments of the present application, the words "as an example" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "as an example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the words "as an example" or "for example" is intended to present the relevant concepts in a specific way.

[0052] The terms used in the implementation section of this application are only used to explain the specific embodiments of this application and are not intended to limit this application.

[0053] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0054] See also Figure 1 , which is a flow chart of a method for compensating overlay errors in a lithography process provided in an embodiment of the present application, the method comprising:

[0055] S101: Acquire overlay error distribution data.

[0056] Using a photolithography machine, the mask and the wafer are precisely aligned, and the wafer coated with photoresist is exposed by the light source in the photolithography machine. The photoresist undergoes a chemical reaction under light, and a corresponding photolithography pattern is formed according to the pattern of the mask. Then, the wafer is placed in a developer to remove the exposed photoresist (positive photoresist) or the unexposed photoresist (negative photoresist) to obtain a photoresist mask. Among them, a suitable type of photolithography machine can be selected according to actual needs, such as a nanoimprint photolithography machine, a plasma photolithography machine, or a contact photolithography machine; the wafer can be a silicon wafer, a germanium wafer, a quartz glass substrate, or a substrate made of a compound semiconductor material composed of group III elements and group V elements, etc.

[0057] As an example, a high-resolution optical microscope with image recognition and measurement functions can be used to scan the displayed lithography pattern through an automated measurement system to accurately capture the offset of the lithography pattern on the X and Y axes, and obtain the offset values ​​(i.e., overlay errors) δx and δy between the lithography pattern and the reference pattern at each acquisition point on the wafer. The measurement process needs to be carried out in a clean and temperature-stable environment to prevent external interference from affecting the accuracy of the data.

[0058] Optionally, the overlay error distribution data may include the offset value between the lithographic pattern and the reference pattern at each acquisition point, as well as parameters such as the error distribution mode and the root mean square error. The overlay error distribution data may be saved in a table or matrix form, and after being digitized, packaged into a standard format suitable for inputting a compensation model, so as to be used for compensation of overlay errors in subsequent steps.

[0059] Optionally, the absolute mean value of the offset value of each acquisition point and the sum of three times the standard deviation can be calculated to obtain the overlay error; if the overlay error is less than a preset error threshold, it can be considered that the current overlay error is within an acceptable range and does not need to be compensated, and the photolithography process can continue; if the overlay error is greater than or equal to the preset error threshold, it can be considered that the current overlay error is large and needs to be compensated before continuing the photolithography process.

[0060] S102: Based on the overlay error distribution data, a target compensation solution is obtained through a pre-established compensation model.

[0061] The inventors have found that temperature changes and applied stress can cause the mask to deform, and the mask pattern to deform and shift, thereby causing the overlay error to change. In the embodiment of the present application, the overlay error distribution data is transmitted to the compensation model. The compensation model can analyze the overlay error distribution data, calculate the compensation stress and thermal dose and other parameters required to compensate for the overlay error, and provide a corresponding target compensation scheme. Among them, the target compensation scheme includes a target stress compensation scheme and a target local thermal compensation scheme. By performing stress compensation and local thermal compensation, the overlay error caused by the compensation stress and the compensation thermal dose is complementary to the original overlay error, thereby achieving compensation for the overlay error.

[0062] As an example, the compensation model can be Figure 2 The steps shown establish:

[0063] S21: Acquire the overlay error distribution data, the in-field coordinates of the exposure field corresponding to each acquisition point, the first correlation relationship between the compensation parameters, and a plurality of optional compensation schemes.

[0064] As an example, the overlay error distribution data, the in-field coordinates of the exposure field corresponding to each acquisition point, and the compensation parameters have a first correlation relationship as shown below:

[0065] δx=k1+k3·x+k5·y+k7·x 2 +k9·xy+k 11 · y 2 +k 13 · x 3 +k 15 · x 2 y+k 17 ·xy 2 +k 19 ·y 3 ;

[0066] δy=k2+k4·y+k6·x+k8·y 2 +k 10 ·xy+k 12 · x 2 +k 14 ·y 3 +k 16 ·y 2 x+k 18 ·yx 2 +k 20 ·x 3 .

[0067] Among them, k1, k2,…, k 20The compensation parameters for the lithography machine to compensate for the overlay error by adjusting the position or parameters of components such as the wafer worktable, mask worktable and projection lens system; (x, y) is the in-field coordinate of each exposure field (i.e., acquisition point).

[0068] For example, it can be based on Figure 3 The optional compensation schemes for the stress around the mask and the local thermal dose input are shown. For example, 16 stress actuators are set in the lithography machine, and the stress actuators are symmetrically arranged around the mask. Every 4 stress actuators are arranged on the same side of the mask. Under the premise of meeting the basic principles of elastic deformation and moment balance of the mask, 16 stress compensation schemes for the hinges around the mask and the local thermal compensation scheme for the local thermal dose input can be designed. Among them, the stress compensation schemes can include 8 schemes in which stress actuators appear in pairs, 4 schemes with two symmetrical features, and 4 schemes with symmetrical features.

[0069] S22: Based on the first association relationship, multiple optional compensation schemes are simulated through a simulation model to establish a second association relationship between the compensation schemes and the compensation parameters.

[0070] Optionally, a simulation model that considers the thermal-mechanical coupling effect of the mask can be constructed in advance based on the physical parameters of the mask in actual near-field lithography, such as the thermal conductivity, expansion coefficient and temperature response of the mask material, as well as the stress around the mask and the local thermal dose input, so as to simulate and execute multiple compensation schemes and accurately predict the deformation and displacement of the mask pattern under different stress and local thermal dose input conditions.

[0071] Through the pre-established simulation model, using the finite element numerical simulation method, iterative testing of various optional compensation schemes can be performed to evaluate the effectiveness of the compensation scheme under different compensation stresses and compensation thermal doses. Through the simulation process, the displacement, deformation and other key responses of the mask under the action of thermal effects and stress distribution can be observed to verify the accuracy of the compensation scheme. Statistical analysis of the functional relationship between different compensation schemes and compensation parameters k can be performed to obtain the distribution of compensation parameters k in different schemes F, such as Figure 4 As shown. Through fitting and optimization, the second correlation relationship between the compensation scheme and the compensation parameters can be established:

[0072] Where F represents the stress compensation scheme, H in Represents a local thermal compensation scheme.

[0073] S23: Establishing a compensation model based on the first association relationship and the second association relationship.

[0074] As an example, the compensation model may include modules such as overlay error distribution data input, target compensation scheme calculation, and target compensation scheme output. It can automatically read and analyze the spatial variation characteristics in the overlay error distribution data, generate control parameters of stress and local thermal dose according to the overlay error distribution data, that is, compensation stress and compensation thermal dose, and then generate a target compensation scheme for the current process conditions. It can flexibly provide suitable target compensation schemes for random and diverse overlay error distribution data.

[0075] Alternatively, see Figure 5 , which is a distribution vector diagram of overlay error provided by an embodiment of the present application, wherein the overlay error of each acquisition point is The distribution is displayed in the form of a vector diagram, and the superposition error in the X and Y directions |mean|+3δ can be marked in the vector diagram, where the superposition error in the X direction can be recorded as OVL x , the stacking error in the Y direction can be recorded as OVL y , thereby more intuitively displaying the distribution of overlay errors, making it easier for technicians to quickly understand the overlay errors that will occur during lithography under current conditions.

[0076] Optionally, after obtaining the target compensation solution, the theoretical displacement deviation of each acquisition point after applying the target compensation solution can also be obtained. The theoretical displacement deviation can be provided by the compensation model. The distribution is shown in the form of vector diagrams, such as Figure 6 , to show the change of overlay error before and after compensation, and to display the correction effect of overlay deviation in each area, so as to further analyze the effectiveness of overlay error compensation.

[0077] Optionally, theoretical residual distribution data can be obtained based on the overlay error distribution data and the theoretical displacement deviation. Through visualization tools, an overlay residual distribution vector diagram can be obtained to intuitively display the theoretical compensation effect, such as Figure 7 .

[0078] S103: driving the stress actuator to apply compensation stress to the mask based on the target stress compensation scheme; and driving the thermal compensation device to apply compensation thermal dose to the mask based on the target local thermal compensation scheme.

[0079] As an example, the stress actuator can be a piezoelectric actuator or other device that can apply a force around the mask. Figure 3 Device with stress conditions shown; the thermal compensation device may include temperature regulating devices such as multiple micro-heaters and micro-coolers to achieve local thermal compensation.

[0080] By controlling the stress actuator to execute the target stress compensation scheme to apply the compensating stress to the mask, and controlling the thermal compensation device to execute the target local thermal compensation scheme to apply the compensating thermal dose to the mask, the target compensation scheme is executed to achieve compensation for the overlay error and correct the overlay error.

[0081] Optionally, after executing the target compensation scheme, the offset value between the lithographic pattern and the reference pattern at each acquisition point may be monitored to obtain actual residual distribution data so as to monitor the compensation effect in real time.

[0082] Optionally, based on the actual residual distribution data, the absolute mean value of the offset value of each acquisition point and the sum of three times the standard deviation are calculated to obtain the first data, that is, the superposition error of the residual; if the first data is greater than the preset threshold for more than a preset number of consecutive times, an alarm message is output.

[0083] For example, the preset number of times can be three times. If the first data is greater than the preset threshold three times in a row since the first photolithography after the execution of the target compensation scheme, it can be considered that the overlay error cannot be effectively compensated by the method provided in the embodiment of the present application. At this time, an alarm message is output and the photolithography operation is stopped; if the first data of the first photolithography after the execution of the target compensation scheme is less than or equal to the preset threshold, and in the subsequent execution of the photolithography process, the first data is greater than the preset threshold three times in a row, it can be considered that the overlay error has further changed with the increase in the number of operations. At this time, an alarm message can be output to prompt the target compensation scheme to be re-determined.

[0084] Optionally, the residual error can be calculated based on the actual residual distribution data and the theoretical residual distribution data, and the residual error can be displayed as follows by a visualization tool: Figure 8 The residual error distribution diagram is shown. If the residual error is much smaller than the theoretical deviation, it can be proved that the theoretical residual distribution data calculated by the model is highly consistent with the actual residual distribution data after actual compensation. Then, the theoretical residual distribution data can be used to provide residual prediction for the area where the overlay error compensation is not completed, to ensure the effectiveness of the compensation scheme and provide a reference for subsequent iterative optimization.

[0085] Optionally, during the execution of the photolithography process, stress and local thermal dose can be monitored in real time, and based on the feedback parameters such as stress and local thermal dose, the stress distribution and local thermal dose input around the mask can be dynamically adjusted to keep the mask pattern stable during the exposure process, thereby achieving real-time correction of overlay errors.

[0086] In the embodiment of the present application, first, the overlay error distribution data is obtained; the overlay error distribution data includes the offset value between the lithography pattern and the reference pattern at each acquisition point; then, based on the overlay error distribution data, a target compensation scheme is obtained through a pre-established compensation model; the compensation model is established based on the correlation between the overlay error distribution data, the compensation scheme and the compensation parameters; the target compensation scheme includes a target stress compensation scheme and a target local thermal compensation scheme; finally, based on the target stress compensation scheme, the stress actuator is driven to apply compensation stress to the mask; based on the target local thermal compensation scheme, the thermal compensation device is driven to apply a compensation thermal dose to the mask. Thus, through the pre-established compensation model, the compensation stress and compensation thermal dose required to compensate for the overlay error are reversely obtained according to the overlay error distribution data, and then the mask is deformed by applying the compensation stress and compensation thermal dose to the mask, thereby realizing compensation for the overlay error in the lithography process, which can effectively reduce the overlay error of the lithography process, improve the reliability and yield of the product, and reduce the cost of large-scale production.

[0087] In particular, in order to verify the effectiveness of the overlay error compensation method provided in the embodiment of the present application in improving the lithography accuracy in large-scale integrated circuit production, we took the average value of 24 compensations as a batch and then took 6 batches as a group to analyze the robustness of the method in multi-batch production. Fig. 9 As shown, the overlay error compensation method provided in the embodiment of the present application exhibits a consistent and efficient compensation effect in different groups, and the average compensation ratios in the X direction and the Y direction are both maintained above 90%. It can be seen that the method has good compensation capabilities in all directions.

[0088] See also Fig.10 , this figure is a schematic diagram of a lithography process overlay error compensation device provided in an embodiment of the present application, and the device includes: an acquisition module 1001, a scheme determination module 1002 and a driving module 1003.

[0089] The acquisition module 1001 is used to acquire overlay error distribution data; the overlay error distribution data includes an offset value between the lithographic pattern and the reference pattern at each acquisition point;

[0090] The scheme determination module 1002 is used to obtain a target compensation scheme based on the overlay error distribution data through a pre-established compensation model; the compensation model is established based on the correlation between the overlay error distribution data, the compensation scheme and the compensation parameters; the target compensation scheme includes a target stress compensation scheme and a target local thermal compensation scheme;

[0091] The driving module 1003 is used to drive the stress actuator to apply compensation stress to the mask based on the target stress compensation scheme; and drive the thermal compensation device to apply compensation thermal dose to the mask based on the target local thermal compensation scheme.

[0092] Therefore, through the pre-established compensation model, the compensation stress and compensation heat dose required to compensate for the overlay error are reversely derived according to the overlay error distribution data, and then the mask is deformed by applying the compensation stress and compensation heat dose to the mask, thereby achieving compensation for the overlay error in the lithography process, which can effectively reduce the overlay error of the lithography process, improve the reliability and yield of the product, and reduce the cost of large-scale production.

[0093] Optionally, another lithography process overlay error compensation device provided in the present application also includes: a model building module; used to obtain overlay error distribution data, the in-field coordinates of the exposure field corresponding to each acquisition point, and a first correlation between compensation parameters, and multiple optional compensation schemes; based on the first correlation, simulating the multiple optional compensation schemes through a simulation model to establish a second correlation between the compensation schemes and compensation parameters; based on the first correlation and the second correlation, establishing a compensation model.

[0094] Optionally, the model building module is also used to build a simulation model based on the physical parameters of the mask, the stress around the mask and the local thermal dose input; the simulation model is used to predict the deformation and displacement information of the mask pattern under different stress and local thermal dose input conditions.

[0095] Optionally, another lithography process overlay error compensation device provided in the present application also includes: a residual error calculation module, used to obtain actual residual distribution data and theoretical residual distribution data; the residual distribution data is the overlay error distribution data after overlay error compensation; based on the actual residual distribution data and the theoretical residual distribution data, the residual error is calculated.

[0096] Optionally, another lithography process overlay error compensation device provided by the present application also includes: an alarm module; used to monitor actual residual distribution data; the actual residual distribution data includes the offset value between the lithography pattern of each acquisition point and the reference pattern; based on the actual residual distribution data, the absolute mean value and the sum of three times the standard deviation of the offset value of each acquisition point are calculated to obtain first data; if the first data is greater than a preset threshold for more than a preset number of consecutive times, an alarm message is output.

[0097] Optionally, another lithography process overlay error compensation device provided by the present application also includes: a visualization module; used to obtain the theoretical displacement deviation of each acquisition point after applying the target compensation scheme; and obtain an error compensation vector diagram based on the theoretical displacement deviation of each acquisition point.

[0098] In addition, an embodiment of the present application also provides a lithography machine, which includes: a controller stress actuator and a thermal compensation device; wherein the controller is electrically connected to the stress actuator and the thermal compensation device; the controller is used to drive the stress actuator to execute a target stress compensation scheme according to the above-mentioned lithography process overlay error compensation steps, and drive the thermal compensation device to execute a target local thermal compensation scheme.

[0099] Alternatively, if Figure 3 As shown, the lithography machine includes 16 stress actuators; the stress actuators are symmetrically arranged around the mask; and every 4 stress actuators are arranged on the same side of the mask.

[0100] Optionally, the thermal compensation device includes a plurality of micro heaters and micro coolers, and the stress actuator may be a piezoelectric actuator.

[0101] It should be noted that each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device and equipment embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiments. The device and equipment embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components indicated as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. A person of ordinary skill in the art can understand and implement it without paying creative labor.

[0102] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for compensating overlay error in a photolithography process, characterized in that: The method comprises: Acquire overlay error distribution data; the overlay error distribution data includes an offset value between the lithographic pattern at each acquisition point and a reference pattern; Based on the overlay error distribution data, a target compensation scheme is obtained through a pre-established compensation model; the compensation model is established based on the correlation between the overlay error distribution data, the compensation scheme and the compensation parameters; the target compensation scheme includes a target stress compensation scheme and a target local thermal compensation scheme; Based on the target stress compensation scheme, a stress actuator is driven to apply compensation stress to the mask; based on the target local thermal compensation scheme, a thermal compensation device is driven to apply compensation thermal dose to the mask.

2. The method according to claim 1, characterized in that The compensation model is established by the following method: Acquire the overlay error distribution data, the in-field coordinates of the exposure field corresponding to each acquisition point, the first correlation relationship between the compensation parameters, and a plurality of optional compensation schemes; Based on the first association relationship, simulating the multiple optional compensation schemes through a simulation model to establish a second association relationship between the compensation schemes and the compensation parameters; A compensation model is established based on the first association relationship and the second association relationship.

3. The method according to claim 2, characterized in that Before simulating the plurality of optional compensation schemes based on the first association relationship through a simulation model to establish a second association relationship between the compensation schemes and the compensation parameters, the method further includes: A simulation model is established based on the physical parameters of the mask, the stress around the mask and the local thermal dose input; the simulation model is used to predict the deformation and displacement information of the mask pattern under different stress and local thermal dose input conditions.

4. The method according to claim 1, characterized in that said driving a stress actuator to apply compensation stress to the mask based on said target stress compensation scheme; After driving the thermal compensation device to apply a compensation thermal dose to the mask based on the target local thermal compensation scheme, the method further includes: Acquire actual residual distribution data and theoretical residual distribution data; the residual distribution data is overlay error distribution data after overlay error compensation; A residual error is calculated based on the actual residual distribution data and the theoretical residual distribution data.

5. The method according to claim 1, characterized in that said driving a stress actuator to apply compensation stress to the mask based on said target stress compensation scheme; After driving the thermal compensation device to apply a compensation thermal dose to the mask based on the target local thermal compensation scheme, the method further includes: Monitoring actual residual distribution data; the actual residual distribution data includes an offset value between the lithographic pattern and the reference pattern at each acquisition point; Based on the actual residual distribution data, the absolute average value of the offset value of each acquisition point and the sum of three times the standard deviation are calculated to obtain first data; If the first data is greater than the preset threshold value for more than the preset number of consecutive times, an alarm message is output.

6. The method according to claim 1, characterized in that After obtaining a target compensation solution based on the overlay error distribution data through a pre-established compensation model, the method further includes: Obtaining the theoretical displacement deviation of each acquisition point after applying the target compensation scheme; Based on the theoretical displacement deviation of each acquisition point, an error compensation vector diagram is obtained.

7. A device for compensating overlay error in a photolithography process, characterized in that: The method device comprises: an acquisition module, a scheme determination module and a driving module; The acquisition module is used to acquire overlay error distribution data; the overlay error distribution data includes an offset value between the lithographic pattern at each acquisition point and the reference pattern; The scheme determination module is used to obtain a target compensation scheme based on the overlay error distribution data through a pre-established compensation model; the compensation model is established based on the correlation between the overlay error distribution data, the compensation scheme and the compensation parameters; the target compensation scheme includes a target stress compensation scheme and a target local thermal compensation scheme; The driving module is used to drive the stress actuator to apply compensation stress to the mask based on the target stress compensation scheme; and drive the thermal compensation device to apply compensation thermal dose to the mask based on the target local thermal compensation scheme.

8. A photolithography machine, characterized in that: The photolithography machine comprises: a controller, a stress actuator and a thermal compensation device; The controller is electrically connected to the stress actuator and the thermal compensation device; The controller is used for driving the stress actuator to execute a target stress compensation scheme and driving the thermal compensation device to execute a target local thermal compensation scheme according to the step of overlay error compensation in the lithography process according to any one of claims 1 to 5.

9. The photolithography machine according to claim 8, characterized in that: The photolithography machine comprises 16 stress actuators; the stress actuators are symmetrically arranged around the mask; and every four stress actuators are arranged on the same side of the mask.

10. The photolithography machine according to claim 8, characterized in that: The thermal compensation device includes a plurality of micro heaters and micro coolers.

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