CN109696804B

CN109696804B - Overlay offset measurement compensation method and device and storage medium

Info

Publication number: CN109696804B
Application number: CN201711003144.2A
Authority: CN
Inventors: 不公告发明人
Original assignee: Changxin Memory Technologies Inc
Current assignee: Changxin Memory Technologies Inc
Priority date: 2017-10-24
Filing date: 2017-10-24
Publication date: 2021-07-09
Anticipated expiration: 2037-10-24
Also published as: CN109696804A

Abstract

The invention provides at least one overlay measurement method, which comprises the following steps: obtaining a first parameter and a second parameter of an exposure unit; calculating a first overlay offset of the exposure unit based on the first parameter; measuring a second overlay offset of the exposure unit based on the second parameter; obtaining a correlation coefficient of the first overlay offset and the second overlay offset; and calculating a third overlay offset of the exposure unit, wherein the third overlay offset is the first overlay offset multiplied by the correlation coefficient. The overlay measurement compensation method provided by the embodiment of the invention can be directly applied to an exposure machine to realize CPE measurement, and the measurement time is short, so that the CPE measurement frequency can be increased, the overlay accuracy is improved, the production period of a product is shortened, the yield is improved, and the production cost is reduced.

Description

Overlay offset measurement compensation method and device and storage medium

Technical Field

The invention relates to the field of semiconductor manufacturing, in particular to a method and a device for measuring and compensating overlay offset of a semiconductor in a photoetching process and a storage medium.

Background

The photolithography process is applied to a semiconductor manufacturing process, and transfers a circuit structure in a pattern form on a Mask (Mask) to the surface of a wafer coated with photoresist through the steps of alignment, exposure, development and the like, so as to form a layer of photoresist Mask pattern on the surface of the wafer.

The semiconductor device is formed by overlapping a plurality of layers of circuits, so tens of times of photoetching steps are needed, each layer must be ensured to be aligned with a front layer and a rear layer, namely Overlay (Overlay), and the performance of the semiconductor device is directly influenced by large Overlay error, even the device is failed due to short circuit. The overlay measurement device is used for overlay measurement, and the measurement results can be fed back or fed forward to a lithography control system or other processing tool to make corrections at the current layer or at a later layer. Overlay Mark (Overlay Mark) is usually formed at the same time when the circuit structure pattern is formed, and the Overlay offset can be obtained by measuring the Overlay marks of different layers. Common overlay marks include: a Box-in-Box (BIB) mark, an Advanced Imaging Metrology (AIM) mark, and a Diffraction Based Overlay (DBO) mark.

The degree of planarization of the wafer surface affects the focal length of the exposure machine, so that the actual focal length of the exposure machine is different from the preset value, and the size and the profile of the exposed wafer are different from the preset value. The PWG (Patterned Wafer Geometry) measuring device can be used to measure the planar deformation of the Wafer surface and feed the measurement result back to the exposure machine for adjusting the focal length of the exposure machine. This measurement method requires an additional measurement apparatus and requires a sampling measurement to which a sampled wafer needs to be moved, thereby increasing the production cycle time and cost of semiconductor devices.

Disclosure of Invention

The invention provides a method and a device for measuring and compensating overlay offset and a storage medium, which are used for at least solving the technical problems in the prior art.

As one aspect of the present invention, the present invention provides a method for compensating for overlay offset measurement, including:

obtaining a first parameter and a second parameter of an exposure unit, wherein the first parameter comprises a Z-axis value of the exposure unit and the second parameter, and the second parameter comprises an X-axis value and/or a Y-axis value of the exposure unit;

calculating a first overlay offset of the exposure unit, the calculation of the first overlay offset being based on the first parameter;

measuring a second overlay offset of the exposure unit, the measuring of the second overlay offset comprising a re-measurement based on the second parameter;

obtaining a correlation coefficient of the first overlay offset and the second overlay offset; and the number of the first and second groups,

and calculating a third overlay offset of the exposure unit, wherein the third overlay offset is obtained by multiplying the first overlay offset by the correlation coefficient.

In some embodiments, the method of measuring the second overlay offset of the exposure unit comprises concentric alignment mark measurement or advanced imaging mark measurement or diffraction-based overlay mark measurement.

In some embodiments, the second parameter comprises an X-axis value of the exposure unit, the first overlay offset comprises an overlay offset on the X-axis, the first overlay offset is calculated according to the following equation:

the OVX1 is the first overlay offset of the exposure unit on the X axis, Z is the Z axis value of the exposure unit, X is the X axis value of the exposure unit, and d is the thickness of the wafer to be processed.

In some embodiments, the second parameter comprises a Y-axis value of the exposure unit, the first overlay offset comprises an overlay offset on the Y-axis, the first overlay offset is calculated according to the following equation:

OVY1 is the first overlay offset of the exposure unit on the Y axis, Z is the Z axis value of the exposure unit, Y is the Y axis value of the exposure unit, and d is the thickness of the wafer to be processed.

In some embodiments, the third stack pair offset is fed back to a control system, and the control system controls the current lithography layer or the subsequent lithography layer to perform the third stack pair offset correction.

In some embodiments, the correction method includes the control unit controlling the current lithography layer or the subsequent lithography layer to move an overlay compensation amount, the overlay compensation amount being calculated according to the following formula:

COR＝-OV3×P

where COR is the overlay compensation amount, OV3 is the third overlay offset amount, and P is the compensation coefficient.

In some embodiments, the compensation factor is 80% to 90%, inclusive.

As another aspect of the present invention, the present invention also provides an overlay offset measurement compensation apparatus, including:

the device comprises a parameter obtaining unit, a parameter calculating unit and a parameter calculating unit, wherein the parameter obtaining unit is used for obtaining a first parameter and a second parameter of an exposure unit, the first parameter comprises a Z-axis value of the exposure unit and the second parameter, and the second parameter comprises an X-axis value and/or a Y-axis value of the exposure unit;

a first overlay offset calculation unit that calculates a first overlay offset of the exposure unit based on the first parameter;

a second overlay shift amount measurement unit that measures a second overlay shift amount of the exposure unit based on the second parameter;

a correlation coefficient obtaining unit configured to obtain a correlation coefficient between the first overlay offset and the second overlay offset; and the number of the first and second groups,

and a third overlay offset calculation unit configured to calculate a third overlay offset of the exposure unit, where the third overlay offset is obtained by multiplying the correlation coefficient by the first overlay offset.

In some embodiments, the measurement compensation apparatus further includes a feedback unit connected to a control system, the feedback unit feeds back the third stack pair offset to the control system, and the control system controls the current lithography layer or the subsequent lithography layer to perform the third stack pair offset correction.

As another aspect of the present invention, the present invention also provides a computer-readable storage medium storing a computer program, characterized in that the computer program realizes the above-mentioned method when executed by a computer processor.

The embodiment of the invention can shorten the production period of the product and reduce the production cost.

The foregoing summary is provided for the purpose of description only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the present invention will be readily apparent by reference to the drawings and following detailed description.

Drawings

In the drawings, like reference numerals refer to the same or similar parts or elements throughout the several views unless otherwise specified. The figures are not necessarily to scale. It is appreciated that these drawings depict only some embodiments in accordance with the disclosure and are therefore not to be considered limiting of its scope.

FIG. 1 is a schematic diagram of the structure of an exposure machine and a wafer during an exposure process.

FIG. 2 is a schematic view of an exposure unit for a wafer.

Fig. 3 is a flowchart of a method for measuring overlay offset according to the first embodiment.

FIG. 4 is a schematic diagram of the conversion of Z-axis data to X-axis component data.

Fig. 5 is a diagram illustrating a statistical method of the first correlation coefficient.

Fig. 6 is a flowchart of an overlay offset measurement method according to the second embodiment.

Fig. 7 is a flowchart of an overlay offset compensation method according to the second embodiment.

Fig. 8 is a schematic block diagram of an overlay shift amount measurement compensation apparatus according to a third embodiment.

Description of the reference numerals

10: a wafer; 11: an exposure unit; 20: an exposure machine; 21: a light source; 22: masking;

23: a lens; 30: a control system; 101: a first photoresist layer; 102: a second photoresist layer;

41: a parameter acquisition unit; 42: a first overlay offset calculation unit;

43: a second overlay offset measurement unit; 44: a correlation coefficient obtaining unit;

45: a third stacking pair offset calculating unit; 46: and a feedback unit.

Detailed Description

In the following, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

As shown in fig. 1, in the photolithography process, an exposure and development process is performed on a Wafer (Wafer)10 by an exposure machine 20. The exposure machine 20 mainly includes a light source 21 and a lens 22, the wafer 10 is placed under the lens 22, and a pattern on a Mask (Mask)30 is exposed and transferred to the surface of the wafer 10 coated with a photoresist, thereby forming a photoresist Mask pattern on the surface of the wafer 10. As shown in fig. 2, each wafer 10 includes a plurality of exposure units (shots) 11 on the surface, and the pattern on each exposure unit 11 is the same, i.e. the wafer 10 is divided into a plurality of exposure units 11 having a periodic structure.

The semiconductor device requires tens of photolithography steps, i.e., forming a multi-layer circuit structure on the surface of the wafer 10, and it is necessary to ensure that each layer is aligned with the previous layer and the next layer, so that Overlay offset is measured during photolithography, and the Overlay offset is used for feedback to the control system 30, so as to perform compensation correction on the current photolithography layer or the next photolithography layer.

The following embodiment presents a measurement compensation method of overlay offset, which is performed by the control system 30. The control system 30 may comprise a computer component, which may be a dedicated computer outside the exposure machine 20, or a control processing unit inside the exposure machine 20, or a central processor for controlling the entire lithographic apparatus system. The computer component may include a computer-readable storage medium for storing a computer program executable by a computer processor, the computer program may implement the overlay offset measurement compensation method of the following embodiments.

The following embodiments are based on a cartesian coordinate system, as shown in fig. 1 and 2, the direction perpendicular to the plane of the wafer 10 is the Z axis, the plane of the wafer 10 is the X axis and the Y axis, and the overlay offset occurs on the plane of the wafer 10, i.e. the overlay offset includes the overlay offset of the exposure unit 11 on the X axis and the Y axis. The exposure unit 11 has X, Y and Z values on the X-axis, Y-axis and Z-axis, respectively, which are measured on the exposure machine 20.

Example one

As shown in fig. 3, the method for measuring overlay shift amount of the present embodiment includes:

step S101, obtaining a first parameter and a second parameter of the exposure unit 11, wherein the first parameter includes a Z-axis value and the second parameter of the exposure unit 11, the second parameter includes an X-axis value of the exposure unit, that is, the first parameter includes a coordinate value (X, Z), the second parameter includes a coordinate value (X), and the first parameter (X, Z) and the second parameter (X) can be obtained by measurement on the exposure machine 20;

step S102, calculating a first overlay offset of the exposure unit 11, wherein the first overlay offset includes an overlay offset OVX1 on the X-axis, and the calculation is based on a first parameter (X, Z), that is, the overlay offset on the X-axis is obtained by using the Z-axis value of the exposure unit 11;

step S103 of measuring a second overlay shift amount of the exposure unit 11, wherein the second overlay shift amount includes an overlay shift amount OVX2 on the X-axis, which is a re-measurement based on the second parameter (X);

step S104, obtaining a correlation coefficient between the first overlay offset and the second overlay offset, i.e. in this embodiment, obtaining a first correlation coefficient r1 between the first overlay offset OVX1 on the X axis and the second overlay offset OVX2 on the X axis;

step 105, calculating a third overlay offset of the exposure unit 11, where the third overlay offset is the first overlay offset multiplied by a correlation coefficient, and in this embodiment, the third overlay offset includes an overlay offset OVX3 on the X axis, and can be calculated by the following formula:

equation 1: OVX3 ═ OVX1 × r 1.

In step S102, the first overlay offset OVX1 is calculated based on the first parameter (x, z). The Z-axis value of the exposure unit 11 represents the physical deformation (plane distortion) of the wafer 10, and the overlay offset can be obtained by using the physical deformation amount, and the specific method includes converting the component of the exposure unit 11 on the Z-axis into the component on the X-axis, and the conversion method usually adopts a calculus algorithm. A conversion method of converting the component of the exposure unit 11 in the Z axis into the component in the X axis is given below, and as shown in fig. 4, the wafer 10 is physically deformed in the Z axis direction, wherein the thickness of the wafer 10 is d.

Equation 2:

equation 3:

the calculation formula of the first overlay shift amount OVX1 of the exposure unit 11 on the X axis can be derived from the above formula 2 and formula 3:

equation 4:

in step 103, the measurement of the second overlay offset OV2 is based on the second parameter (x). According to one embodiment, an Overlay Mark (Overlay Mark) may be formed simultaneously with the formation of the circuit structure pattern, and an Overlay offset may be obtained by measuring Overlay marks of different layers. That is, the second Overlay offset OV2 can be measured by a Box-in-Box (BIB) mark measurement method, an Advanced Imaging Metrology (AIM) mark measurement method, and a Diffraction Based Overlay (DBO) mark measurement method. Those skilled in the art will know how to make the measurements and will not be elaborated upon here.

In step S104, the first correlation coefficient r1 is obtained by obtaining a first correlation coefficient r1 through a statistical algorithm based on a number of exposure units 11, that is, the first overlay shift amount and the second overlay shift amount of the plurality of exposure units 11 on the X axis. The more the number of values of the exposure unit 11 is, the more accurate the obtained first correlation coefficient r1 is.

The correlation coefficient is a statistical index for reflecting the degree of closeness of the correlation between the variables, and is a quantity of the degree of linear correlation between the two variables. There are many ways of defining and statistical methods for the correlation coefficient depending on the subject. As shown in fig. 5, according to an embodiment, a first overlay shift amount OVX1 and a second overlay shift amount OVX2 of the plurality of exposure units 11 on the X axis may be input into the coordinate system to obtain a first correlation coefficient r 1. After absolute values are taken, r1 is 0 to 0.09 and represents that the first overlay offset OVX1 and the second overlay offset OVX2 have no correlation, r1 is 0.1 to 0.3 and represents that the first overlay offset OVX1 and the second overlay offset OVX2 are weak correlation, r1 is 0.3 to 0.5 and represents that the first overlay offset OVX1 and the second overlay offset OVX2 are medium correlation, and r1 is 0.5 to 1.0 and represents that the first overlay offset OVX1 and the second overlay offset OVX2 are strong correlation.

After obtaining the first correlation coefficient r1, the formula 1 and formula 4 can be used to obtain the calculation formula of the third overlay shift amount OVX3 of the exposure unit 11 on the X axis:

equation 5:

in the testing stage of the wafer control wafer (wafer without processing), the overlay shift measurement method according to the embodiment can obtain the first correlation coefficient r 1. In the subsequent mass production stage, the overlay offset (the third overlay offset OVX3 on the X axis) can be measured on the exposure machine 20 by the Z-axis data of the wafer 10 in the exposure machine 20 and the first correlation coefficient r1 obtained in the test stage, that is, the overlay offset in the mass production stage is measured by formula 5.

After the overlay offset is obtained, the overlay offset is fed back to the control system 30 for correction, that is, the third overlay offset OVX3 on the X axis is fed back to the control system 30, the control system 30 controls the current lithography layer or the next lithography layer to move the overlay compensation amount COR on the X axis, and the calculation formula of the overlay compensation amount COR is as follows:

equation 6: COR ═ OV3 × P.

In this embodiment, OV3 is the third overlay offset, OV3 is the third overlay offset OVX3 on the X axis, and P is the compensation coefficient, and according to the production experience, after the overlay offset is obtained, the compensation is not 100%, and the compensation coefficient P is usually multiplied by the compensation coefficient P, and the value range of the compensation coefficient P is 80% to 90%, inclusive.

In the prior art, the measurement of overlay offset requires that the wafer is transferred from the Exposure machine to another testing machine for random sampling measurement, the sampling ratio is usually less than 1%, and then the wafer is returned to the Exposure machine for compensation, and the measurement time is long, so the CPE (Correct Per Exposure unit) measurement can be performed only under some specific conditions, and the overlay accuracy is limited. The overlay offset measurement of the embodiment can be directly carried out on the exposure machine, overlay measurement and compensation can be carried out on each exposure unit without sampling, and the measurement time is short, so that the CPE measurement frequency can be increased, the overlay accuracy is improved, the production period of a product is shortened, the yield is improved, and the production cost is reduced.

In the first embodiment, a method for measuring overlay shift of the wafer 10 in the X axis is provided, and in fact, the overlay shift of the wafer 10 in the Y axis also occurs, so that measurement and compensation are also required, which are the same as those in the X axis.

Example two

As shown in fig. 6, the method for measuring overlay shift amount of the present embodiment includes:

step S201, obtaining a first parameter (x, y, z) and a second parameter (x, y) of the exposure unit 11;

step S202, calculating a first overlay offset value OVX1 on the X axis and a first overlay offset value OVY1 on the Y axis of the exposure unit 11, namely converting the Z axis value of the exposure unit 11 into the overlay offset values on the X axis and the Y axis;

step S203, measuring a second overlay offset OVX2 on the X axis and a second overlay offset OVX2 on the Y axis of the exposure sheet 11;

step S204, obtaining a first correlation coefficient r1 of the first overlay offset OVX1 on the X-axis and the second overlay offset OVX2 on the X-axis, and a second correlation coefficient r2 of the first overlay offset OVY1 on the Y-axis and the second overlay offset OVX2 on the Y-axis;

in step 205, a third overlay offset OVX3 on the X axis and a third overlay offset OVY3 on the Y axis of the exposure unit 11 are calculated, which can be calculated by the following formula:

equation 1: OVX3 ═ OVX1 × r 1;

equation 7: OVY3 is OVY1 × r 2.

In step S202, to convert the component of the exposure unit 11 in the Z axis into the components in the X axis and the Y axis, the conversion method generally employs a calculus algorithm. According to the conversion method in the first embodiment, the following results are obtained:

equation 4:

equation 8:

in step 203, the second overlay offset OV2 is measured based on the second parameter (x) and the fourth overlay offset OV4 is measured based on the fourth parameter (y), i.e., using conventional overlay offset measurement equipment and measurement methods known in the art, including concentric alignment mark measurement, advanced imaging metrology mark measurement, and diffraction-based overlay mark measurement.

In step S204, the first correlation coefficient r1 and the second correlation coefficient r2 are obtained based on a plurality of exposure units 11, and the more the number of the exposure units 11 is, the more accurate the obtained first correlation coefficient r1 and the second correlation coefficient r2 are.

After the first correlation coefficient r1 and the second correlation coefficient r2 are obtained, the third overlay shift amounts OVX3 and OVY3 of the exposure unit 11 on the X axis and the Y axis can be obtained:

equation 5:

equation 9:

in the testing stage of the wafer control wafer, the overlay shift amount measurement method according to the embodiment is used to obtain the first correlation coefficient r1 and the second correlation coefficient r 2. In the subsequent mass production stage, the measurement of the overlay offset (the third overlay offset OVX3 and OVY3) in the X axis and the Y axis can be realized on the exposure machine 20 through the Z-axis data of the wafer 10 in the exposure machine 20 and the first correlation coefficient r1 and the second correlation coefficient r2 obtained in the test stage, that is, the measurement of the overlay offset in the mass production stage is performed through the formula 5 and the formula 9.

After the overlay offset is obtained, the overlay offset is fed back to the control system 30 for correction, that is, the third overlay offset OVX3 and OVY3 are fed back to the control system 30, the control system 30 controls the current lithography layer or the next lithography layer to move the overlay compensation amount COR, and the calculation formula of the overlay compensation amount COR is as shown in formula 6. In the present embodiment, the control system 30 controls the current lithography layer or the next lithography layer to move by the first compensation amount COR1 in the X-axis direction and the second compensation amount COR2 in the Y-axis direction, and the calculation formulas of the first compensation amount COR1 and the second compensation amount COR2 are as follows:

equation 10: COR1 ═ OVX3 × P;

equation 11: COR2 ═ OVY3 XP

Wherein, P is a compensation coefficient, and according to the production experience, after the overlay offset is obtained, the compensation is not performed by 100%, and the compensation coefficient P is usually multiplied by the compensation coefficient P, and the value range of the compensation coefficient P is 80% -90%, including the endpoint value.

Fig. 7 is a schematic diagram illustrating a method for measuring and compensating overlay offset in a mass production stage according to the present embodiment, which takes two photolithography layers as an example.

The processed wafer 10 is placed under the lens 22 of the exposure machine 20 to form the first photoresist layer 101, and third overlay offsets OVX3 and OVY3 of the first photoresist layer 101 in the X and Y axes are measured.

Feeding back the third overlay offset OVX3 and OVY3 to the control system 30, and controlling the first lithography layer 101 by the control system 30 to correct, namely controlling the first lithography layer 101 to move a first compensation amount COV1 in the X-axis direction and move a second compensation amount COV2 in the Y-axis direction, and then continuing the next process; alternatively, the third stack pair offsets OVX3 and OVY3 are fed back to the control system 30 and then directly continue to the next process.

The processed wafer 10 is again placed under the lens 22 of the exposure machine 20 to form the second photoresist layer 102, and if the first photoresist layer 101 is not corrected, the control system 30 controls the second photoresist layer 102 to correct, i.e., controls the second photoresist layer 102 to move the first compensation amount COV1 in the X-axis direction, move the second compensation amount COV2 in the Y-axis direction, and then measure the third overlay offset amounts OVX3 'and OVY 3' of the second photoresist layer 102 in the X-axis and Y-axis directions.

The third overlay offset OVX3 'and OVY 3' are fed back to the control system 30, and the control system 30 controls the second photoresist layer 102 to perform correction, i.e. controls the second photoresist layer 102 to move the first compensation amount COV1 'in the X-axis direction, and to move the second compensation amount COV 2' in the Y-axis direction, and then continues to the next process. If there are more lithography layers, then the second lithography layer 102 may not be corrected, but the next lithography layer may be controlled to be corrected.

In the prior art, the measurement of overlay offset requires that the wafer is transferred from the exposure machine to another test machine for random sampling measurement, the sampling proportion is usually less than 1%, and then the wafer is returned to the exposure machine for compensation, the measurement time is long, so the CPE measurement can be performed only under certain specific conditions, and the overlay accuracy is limited. The overlay offset measurement method can be directly carried out on the exposure machine, and overlay measurement and compensation can be carried out on each exposure unit without sampling. The overlay measurement method and the compensation method of the embodiment of the invention can be directly applied to the exposure machine, and the Z-axis data obtained from the exposure machine is decomposed into the X-axis component and the Y-axis component, so that the CPE is measured, and the measurement time is short, therefore, the CPE measurement frequency can be increased, the overlay accuracy is improved, the product production period is shortened, the yield is improved, and the production cost is reduced.

EXAMPLE III

The present invention provides a measurement and compensation device for overlay offset, and the measurement and compensation device for overlay offset according to various embodiments of the present invention will be described below with reference to the accompanying drawings. The foregoing description of the method can be used to understand the overlay offset measurement compensation apparatus according to the embodiments of the present invention.

FIG. 8 shows a schematic block diagram of an overlay offset measurement compensation apparatus according to an embodiment of the present invention. As shown in fig. 8, the measurement compensation apparatus for overlay shift amount according to one embodiment of the present invention includes a parameter obtaining unit 41, a first overlay shift amount calculating unit 42, a second overlay shift amount measuring unit 43, a correlation coefficient obtaining unit 44, and a third overlay shift amount calculating unit 45.

The parameter obtaining unit 41 may obtain the coordinate values of the exposure unit 11 including the first parameter (x, y, z) and the second parameter (x, y) using the exposure machine 20.

The first overlay shift amount calculation unit 42 is connected to the parameter obtaining unit 41, and calculates a first overlay shift amount of the exposure unit 11 based on the first parameter, that is, a component of the exposure unit 11 in the Z axis is converted into overlay shift amounts in the X axis and the Y axis.

The second overlay shift amount measurement unit 43 is connected to the parameter obtaining unit 41, and measures the second overlay shift amount of the exposure unit 11 based on the second parameter, that is, the overlay shift amounts in the X-axis and the Y-axis are measured using conventional measurement methods including concentric alignment type mark measurement, advanced imaging measurement type mark measurement, and diffraction-based overlay mark measurement.

The correlation coefficient obtaining unit 44 is connected to the first overlay offset calculating unit 42 and the second overlay offset measuring unit 43, and is configured to obtain a correlation coefficient between the first overlay offset and the second overlay offset according to a statistical algorithm.

The third overlay shift amount calculation unit 45 is connected to the first overlay shift amount calculation unit 42 and the correlation coefficient obtaining unit 44, and is configured to calculate a third overlay shift amount of the exposure unit 11, where the third overlay shift amount is the first overlay shift amount multiplied by the correlation coefficient.

In the testing stage of the wafer control wafer, the overlay offset measurement apparatus according to the embodiment can obtain the correlation coefficient. In the subsequent mass production stage, measurement of the overlay shift amount (third overlay shift amount) can be performed on the exposure machine 20 by the Z-axis value of the wafer 10 in the exposure machine 20 and the correlation coefficient obtained in the test stage.

The measurement compensation apparatus of the embodiment of the present invention further includes a feedback unit 46, connected to the control system 30, for feeding back the overlay offset (third overlay offset) to the control system 30, and the control system 30 controls the current lithography layer or the subsequent lithography layer to perform the correction of the overlay offset (third overlay offset).

The overlay offset measurement and compensation device provided by the embodiment of the invention can directly measure and compensate overlay offset on the exposure machine 20, CPE measurement and compensation can be carried out on each exposure unit without sampling, and the measurement time is short, so that the CPE measurement frequency can be increased, the overlay accuracy is improved, the production period of products is shortened, the yield is improved, and the production cost is reduced.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.

The logic and/or steps represented in the flowcharts or otherwise described herein, e.g., an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.

It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.

It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.

In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a separate product, may also be stored in a computer readable storage medium. The storage medium may be a read-only memory, a magnetic or optical disk, or the like.

The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive various changes or substitutions within the technical scope of the present invention, and these should be covered by the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. A method for measuring and compensating overlay offset is characterized by comprising the following steps:

calculating a first overlay offset of the exposure unit, wherein the calculation of the first overlay offset is based on the first parameter, and the first overlay offset comprises a component of the Z-axis value on an axis where the second parameter is located;

measuring a second overlay offset of the exposure unit, the measuring of the second overlay offset including a re-measurement based on the second parameter to obtain the second overlay offset by measuring overlay marks of different layers;

2. The overlay shift measurement compensation method of claim 1, wherein the method of measuring the second overlay shift of the exposure unit comprises concentric alignment type mark measurement or advanced imaging mark measurement or diffraction-based overlay mark measurement.

3. The overlay offset measurement compensation method according to claim 1, wherein the second parameter comprises an X-axis value of the exposure unit, the first overlay offset comprises an overlay offset on an X-axis, and the first overlay offset is calculated according to the following formula:

4. The overlay offset measurement compensation method according to any one of claims 1 to 3, wherein the second parameter includes a Y-axis value of the exposure unit, the first overlay offset includes an overlay offset on a Y-axis, and the first overlay offset is calculated according to the following formula:

5. The overlay offset measurement compensation method according to claim 1, further comprising feeding back the third overlay offset to a control system, wherein the control system controls the current lithography layer or the subsequent lithography layer to perform the third overlay offset correction.

6. The overlay offset measurement compensation method of claim 5, wherein said correcting comprises said control system controlling said current lithography layer or said subsequent lithography layer to move an overlay compensation amount, said overlay compensation amount being calculated according to the following formula:

COR＝-OV3×P

7. The overlay offset measurement compensation method of claim 6, wherein the compensation factor is 80% to 90%, inclusive.

8. An overlay offset measurement compensation apparatus, comprising:

a first overlay offset calculation unit, configured to calculate a first overlay offset of the exposure unit based on the first parameter, where the first overlay offset includes a component of the Z-axis value on an axis where the second parameter is located;

a second overlay offset measurement unit configured to measure a second overlay offset of the exposure unit, the measurement of the second overlay offset including a re-measurement based on the second parameter to obtain the second overlay offset of the exposure unit by measuring overlay marks of different layers;

9. The measurement compensation apparatus of claim 8, further comprising a feedback unit connected to a control system, wherein the feedback unit feeds back the third stack offset amount to the control system, and the control system controls the current lithography layer or the subsequent lithography layer to perform the third stack offset correction.

10. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a computer processor, implements the method of any of claims 1-7.