A method for aligning the pattern positions between an EUV lithography machine and a DUV lithography machine

Abstract

The present application provides a method for aligning the positions of patterns between an EUV lithography machine and a DUV lithography machine, belonging to the technical field of lithography machines. Specifically, it includes: fabricating an EUV photomask with a first measurement pattern and a DUV photomask with a second measurement pattern; measuring the positions of the first measurement pattern and the second measurement pattern, and calculating the position deviation value A between the two; using the EUV lithography machine to perform the first-layer exposure on the wafer through the fabricated EUV photomask; using the DUV lithography machine to perform the second-layer exposure on the wafer through the fabricated DUV photomask; measuring the position deviation value B between the pattern of the first layer and the pattern of the second layer; calculating the position correction value C of the photomask according to the position deviation value A and the position deviation value B; compensating the position correction value C to the EUV photomask or the DUV photomask by using the GMC function of the photomask lithography machine. Through the processing solution of the present application, the yield of the chip is improved.

Description

Technical Field

[0001] The present application relates to the technical field of lithography machines, and in particular to a method for aligning graphic positions between an EUV lithography machine and a DUV lithography machine. Background Art

[0002] During the chip manufacturing process, the alignment of the graphic positions between layers is an important factor affecting the chip quality and yield. Poor alignment will affect the electrical properties and even cause the upper and lower layer circuits to be blocked, resulting in a decrease in output yield.

[0003] The 5-nanometer chip process has used EUV lithography technology in some key layers, and DUV lithography technology is still used in other layers. Due to the differences in the optical systems of the two lithography technologies, there will still be a residual deviation even after position alignment correction. If this residual deviation can be reduced, it will be of great help in improving chip yield.

[0004] EUV and DUV lithography machines have the function of pattern alignment correction. Before starting exposure, the lithography machine will first measure the position of the calibration pattern on the wafer, calculate its deviation, and simulate the correction coefficient with a high-order polynomial. This correction coefficient is then fed back to the optical system to correct the position of the lithography pattern. This method has a better correction effect for linear deviations such as displacement, magnification, and rotation, but it cannot completely correct nonlinear deviations such as distortion and protrusions, and there will be a correction residual value.

[0005] The deviation of the graphic position between the two optical systems of EUV and DUV lithography machines includes linear and nonlinear deviations. After the graphic position alignment correction, the front and back layers exposed by the two lithography machines will still have a deviation residual value of 1 to 5nm. Summary of the invention

[0006] In view of this, an embodiment of the present application provides a method for aligning graphic positions between an EUV lithography machine and a DUV lithography machine, which at least partially solves the problem in the prior art that there are still residual deviations after correction of the graphic position alignment between the two optical systems of the EUV and DUV lithography machines.

[0007] The embodiment of the present application provides a method for aligning pattern positions between an EUV lithography machine and a DUV lithography machine, the method comprising:

[0008] Manufacturing an EUV photomask having a first measurement pattern and a DUV photomask having a second measurement pattern;

[0009] Measuring the positions of the first measurement pattern and the second measurement pattern, and calculating a position deviation value A between the two;

[0010] Use an EUV lithography machine to expose the first layer of the wafer through the manufactured EUV photomask;

[0011] Performing a second layer exposure on the wafer using a DUV lithography machine through a manufactured DUV photomask;

[0012] Measuring a position deviation value B between the pattern of the first layer and the pattern of the second layer;

[0013] Calculate a position correction value C of the photomask according to the position deviation value A and the position deviation value B;

[0014] The position correction value C is compensated to the EUV photomask or the DUV photomask using the GMC function of the photomask lithography machine.

[0015] According to a specific implementation manner of the embodiment of the present application, center points of the first measurement pattern and the second measurement pattern coincide with each other.

[0016] According to a specific implementation manner of the embodiment of the present application, the first measurement pattern and the second measurement pattern do not overlap.

[0017] According to a specific implementation manner of the embodiment of the present application, the first measurement pattern and the second measurement pattern are both set to be multiple, and the positions of each first measurement pattern and each second measurement pattern are set relative to each other.

[0018] According to a specific implementation of the embodiment of the present application, the first measurement pattern and the second measurement pattern are both arranged in a uniform array on the photomask, and the array range is larger than the scanning range of the lithography machine.

[0019] According to a specific implementation of the embodiment of the present application, the calculation formula of the position correction value C is:

[0020] C=N*BA,

[0021] Where N is the miniaturization factor from the photomask pattern to the wafer pattern.

[0022] According to a specific implementation of the embodiment of the present application, a size of the first measurement pattern / the second measurement pattern is less than or equal to 20 μm, and a line width range of the first measurement pattern / the second measurement pattern is 0.5 μm-3 μm.

[0023] According to a specific implementation of the embodiment of the present application, the step of manufacturing an EUV photomask having a first measurement pattern includes:

[0024] Draw a first measurement graph;

[0025] Expose the EUV photomask substrate using a photolithography machine according to the first measurement pattern;

[0026] Bake / develop after exposure;

[0027] performing etching of the hard mask layer;

[0028] Remove the photoresist and etch the ruthenium layer and the multi-layer molybdenum / silicon layer;

[0029] The hard mask layer is removed.

[0030] According to a specific implementation of the embodiment of the present application, the step of making a DUV photomask having a second measurement pattern includes:

[0031] Draw a second measurement graph;

[0032] exposing the DUV photomask substrate using a photolithography machine according to the second measurement pattern;

[0033] Bake / develop after exposure;

[0034] Etching the chromium layer;

[0035] removing the photoresist and etching the molybdenum silicide layer;

[0036] The chromium layer is removed.

[0037] Beneficial Effects

[0038] The method for aligning the graphic position between the EUV lithography machine and the DUV lithography machine in the embodiment of the present application utilizes a photomask to compensate for the residual value of the graphic position deviation between the EUV and DUV lithography machines, thereby achieving better graphic position alignment and effectively improving the quality and yield of the chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments 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.

[0040] Figure 1 This is a flow chart of a method for aligning pattern positions between an EUV lithography machine and a DUV lithography machine according to an embodiment of the present invention;

[0041] Figure 2 is a schematic diagram of calculating a position deviation value A according to an embodiment of the present invention;

[0042] Figure 3 is a schematic diagram of calculating a position deviation value B according to an embodiment of the present invention;

[0043] Figure 4 A schematic structural diagram of an EUV photomask substrate according to an embodiment of the present invention;

[0044] Figure 5 FIG. 4 is a schematic structural diagram of a DUV photomask substrate according to an embodiment of the present invention.

[0045] In the figure: 1. Photoresist layer; 2. Hard mask layer; 3. Ruthenium layer; 4. Multilayer Mo / Si layer; 5. Low thermal expansion material base layer; 6. Chromium layer; 7. Molybdenum silicide layer; 8. Quartz layer. DETAILED DESCRIPTION

[0046] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0047] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0048] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0049] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0050] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0051] The present application embodiment provides a method for aligning pattern positions between an EUV lithography machine and a DUV lithography machine. Figures 1 to 5 Describe in detail.

[0052] The pattern position alignment method between the EUV lithography machine and the DUV lithography machine in this embodiment refers to Figure 1 , specifically including:

[0053] Step 1: Prepare an EUV photomask having a first measurement pattern and a DUV photomask having a second measurement pattern. In this step, the EUV photomask needs to use an EUV photomask substrate. The structure of the EUV photomask substrate is as follows: Figure 4 As shown, the film layers included from top to bottom are: photoresist layer 1, hard mask layer 2, ruthenium layer 3, multi-layer molybdenum / silicon layer 4 and low thermal expansion material base layer 5; the DUV photomask substrate used by the DUV photomask is generally an attenuated phase shift mask substrate, and its structure refers to Figure 5 , the film layers from top to bottom are: photoresist layer 1, chromium layer 6, molybdenum silicide layer 7 and quartz layer 8.

[0054] Specifically, the steps of manufacturing an EUV photomask having a first measurement pattern include:

[0055] Step 111, drawing a first measurement graph;

[0056] Step 112, exposing the EUV photomask using a photolithography machine according to the first measurement pattern;

[0057] Step 113, baking / developing after exposure;

[0058] Step 114, etching the hard mask layer 2;

[0059] Step 115, removing the photoresist layer 1, and etching the ruthenium layer 3 and the multi-layer molybdenum / silicon layer 4;

[0060] Step 116 , removing the hard mask layer 2 .

[0061] Specifically, the steps of making a DUV photomask having a second measurement pattern include:

[0062] Step 121, drawing a second measurement graph;

[0063] Step 122, exposing the DUV photomask using a photolithography machine according to the second measurement pattern;

[0064] Step 123, baking / developing after exposure;

[0065] Step 124, etching the chromium layer 6;

[0066] Step 125, removing the photoresist layer 1, and etching the molybdenum silicide layer 7;

[0067] Step 126 , removing the chromium layer 6 .

[0068] Step 2: Measure the positions of the first measurement pattern and the second measurement pattern, and calculate the position deviation value A between the two.

[0069] Specifically, refer to Figure 2 In the figure, the black grid points represent the ideal position, and the arrows represent the size and direction of the point deviation. The dotted arrows represent the size and direction of the point deviation on the EUV photomask, the dotted arrows represent the size and direction of the point deviation on the DUV photomask, and the solid arrows represent the position deviation value A of the points on the two photomasks.

[0070] Step 3: Use an EUV lithography machine to perform first layer exposure on the wafer through the manufactured EUV photomask, that is, prepare a first measurement pattern on the first layer.

[0071] Step 4: Use a DUV lithography machine to expose the wafer to the second layer through the manufactured DUV photomask, and prepare a second measurement pattern on the second layer. At this time, the first layer and the second layer are in a front-to-back layer relationship. In order to calculate the position deviation, the center points of the first measurement pattern and the second measurement pattern coincide to confirm their pattern registration. Furthermore, the first measurement pattern and the second measurement pattern do not overlap.

[0072] The shape of the measurement pattern is not particularly limited in this application. For the convenience of measurement, for example, it can be a simple cross, square, rectangle, frame, etc. Due to the measurement range and resolution limitations of the photomask measurement equipment, the size of the first measurement pattern / the second measurement pattern is less than or equal to 20μm, and the line width of the first measurement pattern / the second measurement pattern ranges from 0.5μm to 3μm.

[0073] In order to improve the accuracy of correction, the first measurement pattern and the second measurement pattern are both provided in plurality, and the positions of the first measurement patterns and the second measurement patterns are arranged relative to each other.

[0074] Furthermore, the first measurement pattern and the second measurement pattern are both arranged in an array on the photomask in a uniform manner, and the array range is larger than the scanning range of the photolithography machine of 10.4 cm×13.2 cm.

[0075] Step 5: Measure the position deviation value B between the pattern of the first layer and the pattern of the second layer.

[0076] Specifically, refer to Figure 3In this embodiment, the first measurement figure is set as a smaller square frame and the second measurement figure is set as a larger square frame. In the figure, a point is taken as an example. The horizontal coordinate deviation of the point is recorded as x deviation, and the vertical coordinate deviation is recorded as y deviation. x deviation = (x1-x2) / 2, y deviation = (y1-y2) / 2. The x deviation and y deviation can represent the position deviation value B of the point.

[0077] Step 6: Calculate the position correction value C of the photomask according to the position deviation value A and the position deviation value B. In this step, the specific calculation formula of the position correction value C is:

[0078] C=N*BA,

[0079] Where N is the miniaturization factor from the photomask pattern to the wafer pattern.

[0080] Step 7: Compensate the position correction value C to the EUV photomask or DUV photomask using the GMC (Grid matching correction) function of the photomask lithography machine.

[0081] The GMC function is briefly described here. The position correction value C calculated in step 6 is the position correction value of each point. Here, C is represented as C(Δx ij , Δy ij ), Δx ij is the x-direction deviation of a point, Δy ij is the y-direction deviation of a certain point, so the calculation formula for the position deviation value of each point is as follows:

[0082] Δx ij =a 0 +a 1 x+a 2 y+a 3 x 2 +a 4 xy+a 5 y 2 +a 6 x 3 +a 7 x 2 y+a 8 xy 2 +a 9 y 3

[0083] Δy ij =b 0 +b 1 x+b 2 y+b 3 x 2 +b 4 xy+b5 y 2 +b 6 x 3 +b 7 x 2 y+b 8 xy 2 +b 9 y 3 ,

[0084] In the formula, x and y are the ideal coordinates of a point, a 0 -a 9 and b 0 -b 9 is the correction coefficient. For each point, x, y, Δx ij and Δy ij All are known, so by substituting the values ​​of multiple points into the above calculation formula, the correction coefficient a can be obtained. 0 -a 9 and b 0 -b 9 The value of 0 -a 9 and b 0 -b 9 The EUV photomask or DUV photomask can be compensated to complete the position correction.

[0085] The embodiment provided by the present invention improves the quality and yield of the chip by compensating the residual value of the pattern position alignment deviation of EUV and DUV lithography machines with a photomask.

[0086] 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 shall be based on the protection scope of the claims.

Claims

1. A method for aligning the pattern positions between an EUV lithography machine and a DUV lithography machine, characterized in that, the method includes: manufacturing an EUV photomask with a first measurement pattern and a DUV photomask with a second measurement pattern; measuring the positions of the first measurement pattern and the second measurement pattern, and calculating the position deviation value A between the two; using the EUV lithography machine to perform the first layer exposure on the wafer through the manufactured EUV photomask; using the DUV lithography machine to perform the second layer exposure on the wafer through the manufactured DUV photomask; measuring the position deviation value B between the pattern of the first layer and the pattern of the second layer; calculating the position correction value C of the photomask according to the position deviation value A and the position deviation value B; wherein, the calculation formula of the position correction value C is: C = N*B - A, where N is the reduction multiple from the photomask pattern to the wafer pattern; compensating the position correction value C to the EUV photomask or the DUV photomask by using the GMC function of the photomask lithography machine.

2. The method for aligning the pattern positions between an EUV lithography machine and a DUV lithography machine according to claim 1, characterized in that, the centers of the first measurement pattern and the second measurement pattern coincide.

3. The method for aligning the pattern positions between an EUV lithography machine and a DUV lithography machine according to claim 2, characterized in that, the first measurement pattern and the second measurement pattern do not overlap.

4. The method for aligning the pattern positions between an EUV lithography machine and a DUV lithography machine according to claim 1, characterized in that, both the first measurement pattern and the second measurement pattern are set to be multiple, and the positions of each first measurement pattern and each second measurement pattern are relatively set.

5. The method for aligning the pattern positions between an EUV lithography machine and a DUV lithography machine according to claim 4, characterized in that, both the first measurement pattern and the second measurement pattern are set in a uniformly arranged array form on the photomask, and the array range is larger than the scanning range of the lithography machine.

6. The method for aligning the pattern positions between an EUV lithography machine and a DUV lithography machine according to any one of claims 1-5, characterized in that, the size of the first measurement pattern / second measurement pattern is less than or equal to 20 μm, and the line width range of the first measurement pattern / second measurement pattern is 0.5 μm - 3 μm.

7. The method for aligning the pattern positions between an EUV lithography machine and a DUV lithography machine according to claim 1, characterized in that, the step of manufacturing the EUV photomask with the first measurement pattern includes: drawing the first measurement pattern; exposing the EUV photomask substrate by using the lithography machine according to the first measurement pattern; performing baking / development after exposure; performing etching of the hard mask layer; removing the photoresist and performing etching of the ruthenium layer and the multi-layer molybdenum / silicon layer; removing the hard mask layer.

8. The method for aligning the pattern positions between an EUV lithography machine and a DUV lithography machine according to claim 1, characterized in that, the step of manufacturing the DUV photomask with the second measurement pattern includes: drawing the second measurement pattern; exposing the DUV photomask substrate by using the lithography machine according to the second measurement pattern; performing baking / development after exposure; Etch the chromium layer; Remove the photoresist and etch the molybdenum silicide layer; Remove the chromium layer.

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