Wafer deviation compensation value calculation method, calculation device and compensation method for lithography machine

Abstract

The application provides a photoetching machine platform wafer deviation compensation value calculation method, a calculation device and a compensation method. The calculation method comprises the following steps: providing a standard wafer and a standard mask, wherein the standard mask is provided with an exposure pattern; performing exposure etching treatment on the standard wafer through the exposure pattern on the standard mask to form a plurality of mark areas on the standard wafer, which are located on the same straight line; performing exposure development treatment on the mark areas of the standard wafer through the standard mask to form an exposure area on each mark area of the standard wafer; obtaining a first deviation value between each mark area and the corresponding exposure area; and calculating a compensation value of the photoetching machine platform according to the first deviation value. The application can calibrate the difference between the photoetching machine platform and the wafer according to the compensation value, and quickly solve the wafer deviation problem among various wafer factories.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit manufacturing technology, and in particular to a method, device and method for calculating the offset compensation value on a lithography machine. Background Technology

[0002] Because wafer fabs currently use lithography machines from different manufacturers, and there is no single standard for wafer fabrication deviation across different fabs, wafer fabrication difficulties arise between them (such as exposure machine alignment failures). Attempting to detect wafer fabrication deviations by continuously blindly adjusting machine parameters is extremely costly in terms of manpower and resources.

[0003] Therefore, it is necessary to provide a novel method, device, and method for calculating the offset compensation value on a lithography machine to solve the aforementioned problems in the prior art. Summary of the Invention

[0004] The purpose of this invention is to provide a method, device and method for calculating wafer loading deviation compensation value on a lithography machine, which can quickly solve the problem of wafer loading deviation between different wafer fabs.

[0005] To achieve the above objectives, the method for calculating the wafer offset compensation value on a lithography machine stage according to the present invention includes:

[0006] A wafer and a standard photomask are provided, wherein the standard photomask has an exposure pattern disposed thereon;

[0007] The wafer is photolithographically etched using the exposure pattern on the standard photomask to form at least one marking region on the wafer, thereby forming a standard wafer.

[0008] The standard wafer is photolithographically processed using the exposure pattern on the standard photomask to form at least one exposure area on the standard wafer.

[0009] Obtain the first-level deviation value between each of the marked areas and the corresponding exposure area;

[0010] The compensation value of the lithography machine is calculated based on the first-level deviation value.

[0011] The beneficial effect of calculating the wafer loading deviation compensation value of the lithography machine described in this invention is as follows: multiple marking areas located on the same straight line are formed on the wafer by the exposure pattern on the standard photomask. Then, the marking areas on the standard wafer are photolithographically processed by the standard photomask, thereby forming corresponding exposure areas near the marking areas. Then, the compensation value of the lithography machine is calculated by the first-level deviation value between the marking areas and the corresponding exposure areas. The difference between the lithography machine and the wafer can be calibrated according to the compensation value, which can quickly solve the problem of wafer loading deviation between various wafer fabs.

[0012] Optionally, in the step of photolithographic etching of the wafer using the exposure pattern on the standard photomask, multiple marking areas located on the same straight line are formed on the wafer; in the step of photolithographic etching of the standard wafer using the exposure pattern on the standard photomask, multiple exposure areas are correspondingly formed on the standard wafer; and the calculation of the compensation value of the photolithography machine based on the first-level deviation value includes:

[0013] The marking area located in the middle of the plurality of marking areas and the corresponding exposure area are calibrated;

[0014] Calculate the secondary deviation value between the remaining marked areas and the corresponding exposure areas after calibration and alignment based on the primary deviation value;

[0015] The compensation value is calculated based on the secondary deviation value.

[0016] Optionally, the number of marking areas is three, namely a first marking area, a second marking area, and a third marking area. The second marking area is located between the first marking area and the third marking area. The exposure areas corresponding to the first marking area, the second marking area, and the third marking area are respectively the first exposure area, the second exposure area, and the second exposure area. The deviations of the first marking area and the first exposure area in the horizontal and vertical directions are respectively the first horizontal deviation and the first vertical deviation. The deviations of the second marking area and the second exposure area in the horizontal and vertical directions are respectively the second horizontal deviation and the second vertical deviation. The deviations of the third marking area and the third exposure area in the horizontal and vertical directions are respectively the third horizontal deviation and the third vertical deviation.

[0017] Optionally, the calibration process of aligning the marker area located at the middle position of the plurality of marker areas with the corresponding exposure area includes:

[0018] The second marking area and the second exposure area are calibrated and aligned in the horizontal direction according to the second horizontal deviation, and in the vertical direction according to the second vertical deviation.

[0019] Optionally, the secondary deviation values ​​include a first horizontal relative difference, a first vertical relative difference, a second horizontal relative difference, and a second vertical relative difference. The first horizontal relative difference is the difference between the first horizontal deviation and the second horizontal deviation. The first vertical relative difference is the difference between the first vertical deviation and the second vertical deviation. The second horizontal relative difference is the difference between the third horizontal deviation and the second horizontal deviation. The second vertical relative difference is the difference between the third vertical deviation and the second vertical deviation.

[0020] Optionally, the compensation value includes a first compensation value X, a second compensation value Y, and a third compensation value Rot, and the calculation process of the first compensation value X, the second compensation value Y, and the third compensation value Rot satisfies the following formula:

[0021] X = -X²;

[0022] Y = -Y2;

[0023] Rot=0.5*(Arctan(X'2 / (A-Y'2))+Arctan(X'3 / (B-Y'3)));

[0024] Wherein, X1 is the first horizontal difference, Y1 is the second horizontal difference, X'2 is the first horizontal relative difference, Y'2 is the first vertical relative difference, X'3 is the second horizontal relative difference, Y'3 is the second vertical relative difference, A is the distance between the center point of the first marking area and the center point of the second marking area, and B is the distance between the center point of the third marking area and the center point of the second marking area.

[0025] Optionally, the distance between the center point of the first marking area and the center point of the second marking area is equal to the distance between the center point of the third marking area and the center point of the second marking area.

[0026] Optionally, the exposure pattern is cross-shaped, with a width and length of 1000 μm, and is provided with scale markings.

[0027] The present invention also provides a device for calculating the wafer offset compensation value on a lithography machine, comprising:

[0028] The first-level deviation calculation module is used to obtain the first-level deviation value between each of the marked areas and the exposure area at the corresponding position;

[0029] A calibration module is used to calibrate the marking area located in the middle of the plurality of marking areas and the corresponding exposure area;

[0030] The secondary deviation calculation module is used to calculate the secondary deviation value between the remaining marked areas and the corresponding exposure areas after calibration and alignment, based on the primary deviation value;

[0031] The compensation calculation module is used to calculate the compensation value based on the secondary deviation value.

[0032] The present invention also provides an exposure compensation method for a lithography machine, wherein the compensation value obtained by the above-mentioned method for calculating the wafer deviation compensation value of the lithography machine is applied to the lithography machine. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating the method for calculating the wafer deviation compensation value on the lithography machine according to an embodiment of the present invention.

[0034] Figure 2 This is a flowchart of step S500 in the method for calculating the wafer deviation compensation value on the lithography machine according to an embodiment of the present invention.

[0035] Figure 3 The structural block diagram of the lithography machine stage deviation compensation value calculation device described in this embodiment of the invention.

[0036] Figure 4 A schematic diagram of the standard photomask in the method for calculating the offset compensation value on the lithography machine stage according to an embodiment of the present invention.

[0037] Figure 5 A schematic diagram of the exposure pattern in the method for calculating the offset compensation value on the lithography machine stage according to an embodiment of the present invention.

[0038] Figure 6 A schematic diagram of the structure of a standard wafer in the method for calculating the wafer deviation compensation value on a lithography machine according to an embodiment of the present invention.

[0039] Figure 7 A schematic diagram of the structure of a standard wafer after photolithography in the method for calculating the wafer deviation compensation value on a lithography machine according to an embodiment of the present invention.

[0040] Figure 8 for Figure 7 An enlarged diagram of A in the diagram.

[0041] Figure 9 A schematic diagram illustrating the compensation value calculation process of the lithography machine stage deviation compensation value calculation method described in this embodiment of the invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, but do not exclude other elements or objects.

[0043] To address the problems existing in the prior art, embodiments of the present invention provide a method for calculating the wafer offset compensation value on a lithography machine stage, referring to... Figure 1 It includes the following steps:

[0044] S100. A standard wafer and a standard photomask are provided, wherein the standard photomask has an exposure pattern.

[0045] In some embodiments, reference Figure 4 The exposure pattern 2 on the standard photomask 1 is cross-shaped, and the width and length of the exposure pattern are both 1000 μm. (Reference) Figure 5 The exposure pattern is provided with a scale, wherein the length and width of the exposure pattern refer to the distance between the ends of the exposure pattern.

[0046] The exposure pattern set on the standard photomask makes it easy to create a marking area on the standard wafer. The scale set on the exposure pattern facilitates subsequent size measurement, and the positional deviation between the marking area and the exposure area is determined based on the measurement results to complete the compensation value calculation process without the need to add a separate ruler for measurement.

[0047] It should be noted that the exposure pattern is not limited to a cross shape, but can also be a triangle or a rectangle. This solution does not impose any special limitations on this, and will not be elaborated here.

[0048] S200: The wafer is photolithographically etched using the exposure pattern on the standard photomask to form at least one marking region on the wafer, thereby forming a standard wafer.

[0049] In this embodiment, reference Figure 6 The standard wafer 3 is fabricated by photolithography and etching on the wafer using the exposure pattern on the standard photomask to form multiple marking areas 4, so as to facilitate the subsequent calculation of the compensation value of the photolithography machine using the standard wafer.

[0050] Furthermore, the center of each marked area 4 is located on the same straight line, which facilitates the subsequent formation of exposure areas based on the marked areas and the calculation of compensation values.

[0051] S300. The standard wafer is placed in a photolithography machine, and the standard wafer is photolithographically processed by the exposure pattern on the standard photomask to form at least one exposure area on the standard wafer.

[0052] Specifically, after pre-aligning the marked areas using the exposure pattern on the standard photomask, photolithography is performed near each marked area using the exposure pattern to form an exposure area on the marked area. The resulting pattern is as follows: Figure 7 and Figure 8 As shown, since the lithography equipment used to fabricate the standard wafer in step S200 and the lithography equipment used to form the exposure area in step S300 are not necessarily the same, by placing the standard wafer fabricated in step S200 into the lithography equipment of this scheme, the standard wafer can be lithographically lithographically processed by the lithography equipment of this scheme to obtain the exposure area, thereby facilitating the subsequent calculation of the deviation value through calibration. Furthermore, the scale set on the exposure pattern allows for quick reading of the length of the marking area and the exposure area, facilitating the subsequent calculation of the first-level deviation value.

[0053] S400: Obtain the first-level deviation value between each of the marked areas and the corresponding exposure area.

[0054] In this embodiment, the first-level deviation value is the positional deviation between the marking area and the corresponding exposure area in the horizontal and vertical directions. After measuring the lengths of the exposure area and the marking area through the scale on the exposure pattern, the first-level deviation value between the marking area and the exposure area can be calculated accordingly.

[0055] S500. Calculate the compensation value of the lithography machine based on the first-level deviation value.

[0056] In this embodiment, after calculating the first-level deviation value between the marking area and the exposure area, the compensation value of the lithography machine can be calculated using the corresponding calculation formula. By applying the compensation value to the lithography machine, the differential calibration of lithography machines and wafers from different manufacturers can be completed, and the problem of wafer loading deviation between different wafer fabs can be quickly solved.

[0057] In some embodiments, the compensation value of the lithography machine is calculated based on the first-level deviation value, with reference to... Figure 2 It includes the following steps:

[0058] S501. The marking area located in the middle of the plurality of marking areas and the corresponding exposure area are calibrated.

[0059] S502. Calculate the secondary deviation value between the remaining marked areas and the corresponding exposure areas after calibration and alignment based on the primary deviation value;

[0060] S503. Calculate the compensation value based on the secondary deviation value.

[0061] Specifically, the marking area and the corresponding exposure area in the middle position are first calibrated so that they overlap. After the marking area and the exposure area in the middle position are calibrated and aligned, the secondary deviation value between the remaining marking areas and the corresponding exposure areas is calculated. Then, the compensation value can be calculated based on the primary deviation value and the secondary deviation value.

[0062] It should be noted that, since the marking area and exposure area in the middle position need to be calibrated and aligned, the number of marking areas and exposure areas is an odd number of no less than 3, in order to facilitate calibration and adjustment.

[0063] To further illustrate the calculation process of the compensation value in this application, we will take an example where both the marked area and the exposure area are three. In this embodiment, refer to... Figure 9 The number of marking areas is three, namely a first marking area C1, a second marking area C2, and a third marking area C3. The second marking area C2 is located between the first marking area C1 and the third marking area C3. The exposure areas corresponding to the first marking area C1, the second marking area C2, and the third marking area C3 are the first exposure area D1, the second exposure area D2, and the second exposure area D3, respectively. The horizontal and vertical deviations of the first marking area C1 and the first exposure area D1 are the first horizontal deviation X1 and the first vertical deviation Y1, respectively. The horizontal and vertical deviations of the second marking area C2 and the second exposure area D2 are the second horizontal deviation X2 and the second vertical deviation Y2, respectively. The horizontal and vertical deviations of the third marking area C3 and the third exposure area D3 are the third horizontal deviation X3 and the third vertical deviation Y3, respectively.

[0064] In some embodiments, the calibration process of aligning the marker area located at the middle position of the plurality of marker areas with the corresponding exposure area includes:

[0065] The second marking area C2 and the second exposure area D2 are calibrated and aligned horizontally according to the second horizontal deviation X2, and vertically according to the second vertical deviation Y2. After processing in this way, the second marking area C2 and the second exposure area D2 can be completely overlapped. Furthermore, after the second marking area C2 and the second exposure area D2 are calibrated and overlapped, the secondary deviation values ​​between the first marking area C1 and the first exposure area D1, and between the third marking area C3 and the third exposure area D3, can be calculated.

[0066] Specifically, the secondary deviation values ​​include a first horizontal relative difference X'2, a first vertical relative difference Y'2, a second horizontal relative difference X'3, and a second vertical relative difference Y'3. The first horizontal relative difference X'2 is the difference between the first horizontal deviation X1 and the second horizontal deviation X2. The first vertical relative difference Y'2 is the difference between the first vertical deviation Y1 and the second vertical deviation Y2. The second horizontal relative difference X'3 is the difference between the third horizontal deviation X3 and the second horizontal deviation X2. The second vertical relative difference Y'3 is the difference between the third vertical deviation Y3 and the second vertical deviation Y2.

[0067] In some embodiments, the compensation value includes a first compensation value X, a second compensation value Y, and a third compensation value Rot, and the calculation process of the first compensation value X, the second compensation value Y, and the third compensation value Rot satisfies the following formula:

[0068] X = -X²;

[0069] Y = -Y2;

[0070] Rot=0.5*(Arctan(X'2 / (A-Y'2))+Arctan(X'3 / (B-Y'3)));

[0071] Wherein, X1 is the first horizontal difference, Y1 is the second horizontal difference, X'2 is the first horizontal relative difference, Y'2 is the first vertical relative difference, X'3 is the second horizontal relative difference, Y'3 is the second vertical relative difference, A is the distance between the center point of the first marking area and the center point of the second marking area, and B is the distance between the center point of the third marking area and the center point of the second marking area.

[0072] In some embodiments, the distance A between the center point of the first marking area and the center point of the second marking area is equal to the distance B between the center point of the third marking area and the center point of the second marking area.

[0073] In some other embodiments, the first marking area, the second marking area, and the third marking area are evenly distributed, and a rectangular coordinate system is established with the vertical direction as the Y-axis and the horizontal direction as the X-axis. The center point of the second marking area coincides with the origin of the rectangular coordinate system, which facilitates adjustment.

[0074] For example, if the first marking area, the second marking area, and the third marking area are all located on the Y-axis, and the distance between the first marking area and the second marking area, and the distance between the second marking area and the third marking area are both 140, then the calculation process of the third compensation value Rot satisfies the following formula:

[0075] Rot=0.5*(Arctan(X'2 / (140-Y'2))+Arctan(X'3 / (140-Y'3)))

[0076] The calculation of the wafer loading deviation compensation value of the lithography machine described in this invention involves forming multiple marked areas on the same straight line on a standard wafer using the exposure pattern on a standard photomask. Then, the standard wafer is exposed and developed using a standard photomask, thereby forming corresponding exposure areas near the marked areas. The compensation value of the lithography machine is then calculated based on the first-order deviation value between the marked areas and the corresponding exposure areas. The difference between the lithography machine and the wafer can be calibrated according to the compensation value, which can quickly solve the problem of wafer loading deviation between different wafer fabs.

[0077] This invention provides a device for calculating the wafer offset compensation value on a lithography machine stage, with reference to... Figure 3 ,include:

[0078] The first-level deviation calculation module 301 is used to obtain the first-level deviation value between each of the marked areas and the exposure area at the corresponding position;

[0079] The calibration module 302 is used to perform calibration processing on the mark area located in the middle of the plurality of mark areas and the corresponding exposure area;

[0080] The secondary deviation calculation module 303 is used to calculate the secondary deviation value between the remaining marked areas and the corresponding exposure areas after calibration and alignment based on the primary deviation value;

[0081] The compensation calculation module 304 is used to calculate the compensation value based on the secondary deviation value.

[0082] Since the modules of the above-mentioned lithography machine stage deviation compensation value calculation device correspond one-to-one with the aforementioned steps for calculating the lithography machine stage deviation compensation value, they will not be described again here.

[0083] The present invention also provides an exposure compensation method for a lithography machine, wherein the compensation value obtained by the above-mentioned method for calculating the wafer deviation compensation value of the lithography machine is applied to the lithography machine.

[0084] After obtaining the compensation value through the above-mentioned method for calculating the wafer loading deviation compensation value on the lithography machine, the compensation value is applied to the lithography machine to complete the calibration of the differences between lithography machines and wafers from different manufacturers, and quickly solve the problem of wafer loading deviation between different wafer foundries.

[0085] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A method for calculating the offset compensation value on a lithography machine stage, characterized in that, include: A wafer and a standard photomask are provided, wherein the standard photomask has an exposure pattern disposed thereon; The wafer is photolithographically etched using the exposure pattern on the standard photomask to form multiple marking areas on the wafer that are located on the same straight line, thereby forming a standard wafer. The standard wafer is placed in a photolithography machine, and the standard wafer is photolithographically processed by the exposure pattern on the standard photomask to form multiple exposure areas on the standard wafer. Obtain the first-level deviation value between each of the marked areas and the corresponding exposure area; The compensation value of the lithography machine is calculated based on the primary deviation value, including: calibrating the marker area located in the middle of the plurality of marker areas with the corresponding exposure area; calculating the secondary deviation value between the remaining marker areas and the corresponding exposure area after calibration and alignment based on the primary deviation value; and calculating the compensation value based on the secondary deviation value.

2. The method for calculating the wafer deviation compensation value on a lithography machine stage according to claim 1, characterized in that, The number of marking areas is three, namely a first marking area, a second marking area, and a third marking area. The second marking area is located between the first marking area and the third marking area. The exposure areas corresponding to the first marking area, the second marking area, and the third marking area are respectively the first exposure area, the second exposure area, and the third exposure area. The deviations of the first marking area and the first exposure area in the horizontal and vertical directions are respectively the first horizontal deviation and the first vertical deviation. The deviations of the second marking area and the second exposure area in the horizontal and vertical directions are respectively the second horizontal deviation and the second vertical deviation. The deviations of the third marking area and the third exposure area in the horizontal and vertical directions are respectively the third horizontal deviation and the third vertical deviation.

3. The method for calculating the wafer deviation compensation value on a lithography machine stage according to claim 2, characterized in that, The calibration process for the marker area located in the middle of the plurality of marker areas and the corresponding exposure area includes: The second marking area and the second exposure area are calibrated and aligned in the horizontal direction according to the second horizontal deviation, and in the vertical direction according to the second vertical deviation.

4. The method for calculating the wafer deviation compensation value on a lithography machine stage according to claim 2, characterized in that, The secondary deviation values ​​include a first horizontal relative difference, a first vertical relative difference, a second horizontal relative difference, and a second vertical relative difference. The first horizontal relative difference is the difference between the first horizontal deviation and the second horizontal deviation. The first vertical relative difference is the difference between the first vertical deviation and the second vertical deviation. The second horizontal relative difference is the difference between the third horizontal deviation and the second horizontal deviation. The second vertical relative difference is the difference between the third vertical deviation and the second vertical deviation.

5. The method for calculating the wafer deviation compensation value on a lithography machine stage according to claim 4, characterized in that, The compensation value includes a first compensation value X, a second compensation value Y, and a third compensation value Rot. The calculation process of the first compensation value X, the second compensation value Y, and the third compensation value Rot satisfies the following formula: ； ； ； Where X1 is the first level difference and Y1 is the second level difference. The first level relative difference, This is the first vertical relative difference. The relative difference at the second level. The second vertical relative difference is A, which is the distance between the center point of the first marking area and the center point of the second marking area, and B is the distance between the center point of the third marking area and the center point of the second marking area.

6. The method for calculating the wafer deviation compensation value on a lithography machine stage according to claim 5, characterized in that, The distance between the center point of the first marking area and the center point of the second marking area is equal to the distance between the center point of the third marking area and the center point of the second marking area.

7. The method for calculating the wafer offset compensation value on a lithography machine stage according to any one of claims 1 to 6, characterized in that, The exposure pattern is cross-shaped, with a width and length of 1000 μm, and is marked with graduations.

8. A device for calculating the film deviation compensation value on an exposure machine table, characterized in that, The calculation device, used for calculating the wafer offset compensation value on the lithography machine stage according to any one of claims 1 to 7, comprises: The first-level deviation calculation module is used to obtain the first-level deviation value between each of the marked areas and the exposure area at the corresponding position; A calibration module is used to calibrate the marking area located in the middle of the plurality of marking areas and the corresponding exposure area; The secondary deviation calculation module is used to calculate the secondary deviation value between the remaining marked areas and the corresponding exposure areas after calibration and alignment, based on the primary deviation value; The compensation calculation module is used to calculate the compensation value based on the secondary deviation value.

9. An exposure compensation method for a photolithography machine, characterized in that, The compensation value obtained by the method for calculating the offset compensation value of the lithography machine stage according to any one of claims 1 to 7 is applied to the lithography machine stage.

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