CN100428058C - In-situ detection method for odd aberration of projection objective lens in lithography machine - Google Patents

Abstract

According to the method, the wave front tilt, the coma aberration and the three-wave aberration in the odd aberration can be accurately measured at the same time according to the imaging position offset measured under different defocus amounts. Compared with the prior art, the method detects the odd aberration based on the change of the defocusing amount, avoids the optimization work of various different numerical apertures and partial coherence factors of the projection objective of the photoetching machine, and has simple detection process. The method of the invention improves the detection precision of the odd aberration due to the increase of the variation range of the sensitivity coefficient.

Description

In-situ detection method for odd aberration of projection objective lens in lithography machine

technical field

The invention relates to a lithography machine, in particular to an in-situ detection method for the odd aberration of the projection objective lens of the lithography machine, and in particular to an in-situ detection method for wavefront tilt, coma and triple wave aberration in the odd aberration of the projection objective lens of the lithography machine.

Background technique

Projection lithography machines for optical lithography are well known in integrated circuit fabrication facilities. In the projection lithography machine, the exposure beam illuminates the mask engraved with the integrated circuit pattern, and the mask is imaged on the substrate through the projection objective lens, so that the photoresist coated on the substrate is exposed.

With the improvement of the integration level of semiconductor integrated circuits, the requirements for photolithography resolution and overlay accuracy are getting higher and higher. The aberration of the projection objective lens is an important factor affecting the resolution and overlay accuracy of lithography. The aberration of a projection objective is usually expressed in terms of wave aberration, which can be decomposed into the form of Zernike polynomials. Wave aberrations decomposed by Zernike polynomials can be divided into idol aberrations and odd aberrations. Odd aberrations include wavefront tilt, coma and triple wave aberration. With the continuous reduction of lithography feature size, especially the use of lithography resolution enhancement technologies such as off-axis illumination, the influence of projection objective lens odd aberration on lithography resolution and overlay accuracy has become more and more prominent. Therefore, high-precision in-situ detection technology for odd aberrations of the projection objective lens of lithography machines is indispensable.

DAMIS (Displacement At Multiple Illumination Settings) is an aberration detection technology based on setting the numerical aperture and partial coherence factor of the projection objective lens. 1], Joost Sytsma, Hans van der Laan, Marco Moers, Rob Willekers. "Improved Imaging Metrology Needed for Advanced Lithography". Semiconductor international 2001, 4). In the prior art [1], first, different numerical apertures and partial coherence factors of the projection objective lens are set, and a mask with multiple test marks is exposed on a substrate coated with photoresist. The structure of any test mark on the mask is shown in Figure 1. After post-baking and developing the substrate, a pattern of mask test marks is formed on the photoresist on the substrate. These patterns are aligned by the optical alignment system in the lithography machine to obtain the imaging position (X, Y) of the mask test mark, and the imaging position offset (ΔX, ΔY) is obtained after comparing with the ideal position. Then use lithography simulation software to determine the sensitivity coefficient under different numerical apertures and partial coherence factors. According to different numerical apertures and partial coherence factors, different imaging position offsets and sensitivity coefficients are obtained, and Zernike coefficients Z ₇ , Z ₈ , Z ₁₄ , and Z ₁₅ , which characterize the coma aberration of the projection objective lens, are obtained by using specific mathematical models and algorithms. DAMIS uses the inherent hardware and functions of the lithography machine to detect aberrations, without adding additional hardware, and realizes the in-situ detection of the coma aberration of the projection objective lens of the lithography machine. The detection method is simple and direct. Unfortunately, this method needs to optimize the numerical aperture and partial coherence factor of the projection objective lens before detection. During the detection process, it is necessary to repeatedly set a variety of different numerical apertures and partial coherence factors, which makes the detection process complicated; With the improvement of the efficiency, DAMIS is gradually unable to meet the needs of the detection accuracy and detection speed of the odd aberration of the projection objective lens.

Contents of the invention

Aiming at the above-mentioned deficiencies in the prior art [1], the present invention provides a high-precision in-situ detection method for odd aberrations of the projection objective lens of a lithography machine.

Based on the change of the defocus amount of the imaging plane, the method realizes simultaneous high-precision in-situ detection of wavefront tilt, coma, and triple wave aberration in the odd aberration of the projection objective lens of the lithography machine. The problems of complicated detection process, low detection precision and slow detection speed in the prior art [1] are solved.

Technical solution of the present invention is as follows:

An in-situ detection method for odd aberrations of a projection objective lens of a photolithography machine, the method comprising the following steps:

① Turn on the light source of the lithography machine, adjust the workpiece table of the lithography machine, so that the substrate carried by the workpiece table is located at a position with a certain amount of defocus;

② The light beam emitted by the light source is adjusted by the lighting system of the lithography machine and irradiated on the mask; the test mark on the mask is imaged on the substrate through the projection objective lens, and the test mark with the defocus amount is obtained after exposure latent image of

③Change the defocus amount Δf of the substrate, repeat the above step ②, and obtain a series of latent image images of test marks with different defocus amounts on the substrate;

④ After post-baking and developing the exposed substrate, use the optical alignment system of the lithography machine to measure the imaging position of the mask test mark pattern on the substrate, and compare it with the theoretical imaging position of the mask test mark pattern to obtain the substrate The offset (ΔX _i , ΔY _i ) of the imaging position of the mask test mark under a series of defocus conditions;

⑤ Determine the sensitivity coefficient S of the odd aberration according to the imaging position offset (ΔX _i , ΔY _i ) of the defocus position;

⑥ Using the imaging position offset (ΔX _i , ΔY _i ) and the sensitivity coefficient S, calculate the odd aberration Z _k of the projection objective lens of the lithography machine through Z _k = S ^-1 · ΔX _i , and the i and k is a positive integer greater than or equal to 1. .

The process of determining the sensitivity coefficient S of the odd aberration includes the following steps:

① Select one of the Zernike coefficients Z _k and the value x of the corresponding Zernike coefficient, and use the lithography simulation software to simulate and gradually obtain the Zernike coefficient Z according to the selected series of defocus positions _k Next series of imaging position simulation offset (Δx _i , Δy _i );

② Using the imaging position simulation offset ( _Δxi , Δy _i ), calculate the odd aberration sensitivity coefficient S _i according to S _i = _Δxi /x, where i and k are positive integers greater than or equal to 1.

The series of defocusing amounts of the substrate carried by the workpiece table are within the selected defocusing range near the focal plane, and the number of defocusing amounts should be greater than 4 at intervals of a certain defocusing step amount.

The mask test marks include a group of horizontal dense lines and a group of vertical dense lines, and the period of the mask test marks is the same as that of the alignment marks used by the optical alignment system.

The number of the mask test marks is 5 or more, and they are evenly distributed in the exposure field of view.

The present invention has the following advantages:

1. Compared with the prior art [1], the variation range of the sensitivity coefficient of the imaging position offset relative to the odd aberration under different defocus amounts adopted by the present invention is increased, and the detection of the odd aberration is improved precision.

2. Compared with the prior art [1], the test mark adopted in the present invention uses a group of horizontal and vertical dense lines to replace the two groups of horizontal and vertical dense lines in the prior art [1], which improves the use of the alignment system to detect The speed of the imaging position of the mask test marks, thereby improving the detection speed of odd aberrations.

3. Compared with the prior art [1], the in-situ detection method for the odd aberration of the projection objective lens proposed by the present invention is based on the defocus of the imaging plane to detect the odd aberration of the projection objective lens in situ, and the detection accuracy of the odd aberration is not affected by the The limitations and effects of the numerical aperture and partial coherence factor settings of the projection objective.

4. Compared with the prior art [1], the present invention avoids the optimization of various numerical apertures and partial coherence factors before detection, and does not need to repeatedly set multiple different numerical apertures and partial coherence factors during detection. Simple.

Description of drawings

The structural representation of the test mark described in the prior art [1] of Fig. 1;

Fig. 2 Schematic diagram of the structure of the projection lithography machine;

Fig. 3 is the detection flowchart of the projection objective lens odd aberration detection technology proposed by the present invention;

Fig. 4 is a schematic structural view of any test mark on the mask of the present invention;

The sensitivity coefficient change curve obtained under different defocus amounts of Fig. 5 of the present invention;

Detailed ways

Below by embodiment the present invention will be further described.

The present invention is applied in a projection photolithography machine as shown in FIG. The projection objective lens 5 with graphics imaged on the substrate 7, the mask table 4 that carries the mask 3 and can be positioned accurately, and the workpiece table 8 is used to carry the substrate 7 and can accurately adjust the defocus amount of the substrate 7 for measurement An optical alignment system 6 for the pattern on the photoresist on the substrate 7 .

The detection process of the in-situ detection method for projection objective lens odd aberration of the present invention is shown in FIG. The specific operation steps of the imaging position offset acquisition process 100, the sensitivity coefficient determination process 200 and the data processing process 300 are as follows:

Imaging position offset acquisition process 100:

(11) Determination of test process conditions: refers to the photoresist type, photoresist thickness, post-baking temperature, post-baking time, developing time and other conditions, which are the same as the general photolithography situation;

(12) Test exposure: adjust the workpiece table 8 so that the substrate 7 carried by the workpiece table 8 is located under the defocus amount _Δf1 ; _The projection objective lens 5 is imaged on the substrate ₇ coated with photoresist _; the _defocus step is selected to be Δf, and the mask The test marks are exposed on the photoresist-coated substrate 7 at a series of out-of-focus positions;

(13) Process treatment: post-baking or developing after post-baking the exposed substrate 7 in the above step (12);

(14) Optical alignment measurement: use the optical alignment system 6 to align the pattern of the mask test mark on the photoresist on the substrate 7 in the above step (13), and obtain the mask test mark at different defocus The imaging position under the measurement is denoted as (X, Y);

(15) Calculation of imaging position offset: According to the theoretical position of any test mark on the mask 3 in the exposure field of view, that is, the nominal position (X _m , Y _m ), and use it to obtain in the above step (14) Calculate the imaging position offset (ΔX, ΔY) of any test mark on the mask 3 according to formula (1),

$\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; \&Delta;X</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}\\ \mathrm{<span\; class="notranslate">\; \&Delta;Y</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

The imaging position offset corresponding to the defocus amount Δf ₁ , Δf ₁ +Δf, Δf ₁ +2Δf, Δf ₁ +3Δf, Δf ₁ +4Δf can be obtained from formula (1) $(\mathrm{\&Delta;}{x}_{\mathrm{\&Delta;}{f}_1},\mathrm{\&Delta;}{Y}_{\mathrm{\&Delta;}{f}_1}),(\mathrm{\&Delta;}{x}_{\mathrm{\&Delta;}{f}_1+\mathrm{\&Delta;\; f}},\mathrm{\&Delta;}{Y}_{\mathrm{\&Delta;}{f}_1+\mathrm{\&Delta;\; f}}),(\mathrm{\&Delta;}{x}_{\mathrm{\&Delta;}{f}_1+2\mathrm{\&Delta;f}},$ $\mathrm{\&Delta;}{Y}_{\mathrm{\&Delta;}{f}_1+2\mathrm{\&Delta;f}}),(\mathrm{\&Delta;}{x}_{\mathrm{\&Delta;}{f}_1+3\mathrm{\&Delta;f}},\mathrm{\&Delta;}{Y}_{{\mathrm{\&Delta;\; f}}_1+3\mathrm{\&Delta;\; f}}),(\mathrm{\&Delta;}{x}_{\mathrm{\&Delta;}{f}_1+4\mathrm{\&Delta;\; f}},\mathrm{\&Delta;}{Y}_{\mathrm{\&Delta;}{f}_1+4\mathrm{\&Delta;\; f}}).$

Sensitivity coefficient determination process 200:

(21) Select a Zernike coefficient Z _k and the value x of this Zernike coefficient, and use the lithography simulation software to simulate to obtain the corresponding imaging position simulation offset;

或或

或

或 (22) Lithography simulation software simulation: Utilize the process conditions determined in the above step (11), use the lithography simulation software to simulate the actual exposure, post-baking, and development processes, and obtain the simulated deviation of the imaging position of the mask test mark under different defocus amounts. displacement Δx _k (Δf ₁ ) or Δy _k (Δf ₁ ),

or or

or

or

按(2)式计算，(23) Determination of sensitivity coefficient: under a certain amount of defocus, the simulated offset of the imaging position is linearly related to the Zernike coefficient representing the odd aberration. Using the imaging position simulation offset Δx _k (Δf ₁ ) or Δy _k (Δf ₁ ) of the mask test mark obtained in the above step (22), the imaging position offset is relative to the Zernike coefficient under the defocus amount Δf ₁ Sensitivity coefficient of Z _k

According to formula (2),

${\mathrm{<span\; class="notranslate">\; S</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; \&Delta;x</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; \&Delta;x</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

From formula (2), it can be obtained that the sensitivity coefficients corresponding to the defocus amount Δf ₁ +Δf, Δf ₁ +2Δf, Δf ₁ +3Δf, Δf ₁ +4Δf are $S_{\mathrm{\&Delta;}{f}_1+\mathrm{\&Delta;f},Z_k},S_{\mathrm{\&Delta;}{f}_1+2\mathrm{\&Delta;f},Z_k},S_{\mathrm{\&Delta;}{f}_1+3\mathrm{\&Delta;f},Z_k},S_{\mathrm{\&Delta;}{f}_1+4\mathrm{\&Delta;\; f},Z_k};$

Data processing process 300:

(31) Odd aberration calculation: any test mark of the mask corresponding to the defocus amount Δf ₁ , Δf ₁ +Δf, Δf ₁ +2Δf, Δf ₁ +3Δf, Δf ₁ +4Δf obtained in the above step (15) Imaging position offset of $(\mathrm{\&Delta;}{x}_{\mathrm{\&Delta;}{f}_1},\mathrm{\&Delta;}{Y}_{\mathrm{\&Delta;}{f}_1}),(\mathrm{\&Delta;}{x}_{\mathrm{\&Delta;}{f}_1+\mathrm{\&Delta;f}},\mathrm{\&Delta;}{Y}_{\mathrm{\&Delta;}{f}_1+\mathrm{\&Delta;f}}),(\mathrm{\&Delta;}{x}_{\mathrm{\&Delta;}{f}_1+2\mathrm{\&Delta;f}},\mathrm{\&Delta;}{Y}_{\mathrm{\&Delta;}{f}_1+2\mathrm{\&Delta;f}}),(\mathrm{\&Delta;}{x}_{\mathrm{\&Delta;}{f}_1+3\mathrm{\&Delta;f}},$ $\mathrm{\&Delta;}{Y}_{\mathrm{\&Delta;}{f}_1+3\mathrm{\&Delta;f}}),(\mathrm{\&Delta;}{x}_{\mathrm{\&Delta;}{f}_1+4\mathrm{\&Delta;\; f}},\mathrm{\&Delta;}{Y}_{\mathrm{\&Delta;}{f}_1+4\mathrm{\&Delta;f}}).$ Obtained by above-mentioned step (23) under above-mentioned defocus amount, the sensitivity coefficient of imaging position offset with respect to Z _k is respectively $S_{\mathrm{\&Delta;}{f}_1,Z_k},S_{\mathrm{\&Delta;}{f}_1+\mathrm{\&Delta;\; f},Z_k},S_{\mathrm{\&Delta;}{f}_1+2\mathrm{\&Delta;f},Z_k},$ $S_{\mathrm{\&Delta;}{f}_1+3\mathrm{\&Delta;f},Z_k},S_{\mathrm{\&Delta;}{f}_1+4\mathrm{\&Delta;\; f},Z_k},$ Where k can be taken as 2, 3, 7, 8, 10, 11, 14, 15 respectively. The odd aberration of the projection objective lens is calculated by the method of least squares according to formula (3),

$\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}\\ {\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 7</span>}}\\ {\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}}\\ {\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}}\\ {\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}\\ {\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 14</span>}}\\ {\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 15</span>}}\end{array}\right]<span\; class="notranslate">\; =</span>{\left[\begin{array}{cccccccc}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 7</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 14</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 15</span>}}}\\ {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 7</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 14</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 15</span>}}}\\ {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 7</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 14</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 15</span>}}}\\ {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 7</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 14</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 15</span>}}}\\ {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 7</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 14</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}}& \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}{<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 15</span>}}}\end{array}\right]}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; \&Delta;X</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}\\ {\mathrm{<span\; class="notranslate">\; \&Delta;Y</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}\\ {\mathrm{<span\; class="notranslate">\; \&Delta;X</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}\\ {\mathrm{<span\; class="notranslate">\; \&Delta;Y</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}\\ {\mathrm{<span\; class="notranslate">\; \&Delta;X</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2\&Delta;</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}\\ {\mathrm{<span\; class="notranslate">\; \&Delta;Y</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2\&Delta;</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}\\ {\mathrm{<span\; class="notranslate">\; \&Delta;X</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 3\&Delta;</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}\\ {\mathrm{<span\; class="notranslate">\; \&Delta;Y</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}\\ {\mathrm{<span\; class="notranslate">\; \&Delta;X</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4\&Delta;</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}\\ {\mathrm{<span\; class="notranslate">\; \&Delta;Y</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}}\end{array}\right]$

(3);

In the above-mentioned step (12), the light source 1 is a mercury lamp or an excimer laser and other ultraviolet, deep ultraviolet and other light sources.

The number and distribution of the test marks on the mask 3 should ensure that at least 5 marks are in the exposure field of view, and the marks are evenly distributed in the field of view. Any of the marking structures should include a set of horizontal dense lines and a set of vertical dense lines, as shown in Figure 4.

The period of the test mark is the same as the period of the alignment mark used by the optical alignment system in the lithography machine.

The series of out-of-focus positions refers to several out-of-focus positions at intervals of a certain defocus step amount within the selected defocus range, and the number of them should be greater than four.

The substrate 7 refers to a semiconductor material wafer with a certain lattice structure, such as a silicon wafer or the like.

The lithography simulation software in the above step (21) refers to software that can accurately simulate the lithography process and effect, such as PROLITH, SOLID-C and other lithography simulation software.

One of the Zernike coefficients in the Zernike coefficients refers to one of the Zernike coefficients that characterize the wavefront tilt, coma, and three-wave aberration in the odd aberration, that is, any one of the Zernike coefficients in Table 1 coefficient.

Table 1 Zernike coefficient and its corresponding odd aberration

Z₂ X is tilted towards the wavefront Z₃ Y is tilted towards the wavefront Z₇ X-direction third-order coma Z₈ Y-direction third-order coma Z₁₀ Three wave difference in X direction Z₁₁ Three wave differences in Y direction Z₁₄ X-direction fifth-order coma Z₁₅ Y-direction fifth-order coma

FIG. 2 is a schematic structural diagram of a projection lithography machine used in this embodiment, wherein the light source 1 is a deep ultraviolet excimer laser. The defocusing range of the workpiece table 9 is 0.2um-1.6um, and the defocusing step is 0.2um. A silicon wafer is used for the substrate 7 . The process conditions are: Sumitomo PAR710 photoresist, the thickness of the film is 1000nm, the post-baking temperature is 95°, the post-baking time is 60s, and the developing time is 60s; the test mark period is 8um. The Zernike coefficient is Z ₇ with a value of 9.65nm. Use the PROLITH lithography simulation software of KLA-Tencor Company for simulation.

The laser light emitted by the light source 1 is irradiated on the mask 3 after passing through the illumination system 2 . Under different defocus amounts, the test marks on the mask 3 are imaged on the substrate 7 coated with photoresist through the projection objective lens 5 . After the substrate 7 is post-baked and developed, the alignment system 6 is used to align the patterns of the mask test marks on the photoresist on the substrate 7 to obtain the imaging positions of the mask test marks under different defocus amounts. After the simulation stage 22 of the lithography simulation software, the sensitivity coefficient of the imaging position offset relative to the Zernike coefficient Z ₇ representing coma under different defocus amounts is obtained, as shown in FIG. 5 .

It can be seen from FIG. 4 that the test mark used in the present invention is half of the test mark in DAMIS, so the time of using the alignment system to detect the imaging position of the mark is shortened by half, and the detection speed of the odd aberration is doubled. In Fig. 5, the variation range of the sensitivity coefficient is 2.1, and the variation range of the sensitivity coefficient in the prior art [1] is 1.6. It can be seen that the variation range of the sensitivity coefficient in the present invention is increased by 0.5 compared with the prior art [1], thus improving the detection accuracy of the odd aberration of the projection objective lens. Under the condition that the detection precision of imaging position offset is constant, the detection precision of the method for in-situ detection of odd aberration of projection objective lens of the present invention is improved by 31.3% compared with the prior art [1].

Claims (5)

1. An in-situ detection method for odd aberrations of a projection objective lens of a lithography machine, characterized in that the method comprises the following steps: ① Turn on the light source (1) of the lithography machine, adjust the workpiece table (8) of the lithography machine, so that the substrate (7) carried by the workpiece table is located at a position with a certain amount of defocus; ② The light beam emitted by the light source (1) is irradiated on the mask (3) after being adjusted by the lighting system (2) of the lithography machine; the test mark on the mask is imaged on the substrate ( 7) On, after exposure, obtain the latent image image of the test mark with the amount of defocus; ③ Change the defocusing amount Δf of the substrate (7), repeat the above step ②, and obtain a series of latent image images of test marks with different defocusing amounts on the substrate (7); ④ After post-baking and developing the exposed substrate (7), use the optical alignment system (6) of the photolithography machine to measure the imaging position of the mask test mark pattern on the substrate (7), and the theoretical imaging of the mask test mark pattern Comparing the positions to obtain the offset (ΔX _i , ΔY _i ) of the imaging position of the mask test mark on the substrate (7) under a series of defocus conditions; ⑤ Determine the sensitivity coefficient S of the odd aberration according to the imaging position offset (ΔX _i , ΔY _i ) of the defocus position; ⑥ Using the imaging position offset (ΔX _i , ΔY _i ) and the sensitivity coefficient S, calculate the Zernike coefficient Z _k corresponding to the odd aberration of the projection objective lens of the lithography machine through Z _k = S ^-1 · ΔX _i , and the The aforementioned i and k are positive integers greater than or equal to 1. 2. According to the in-situ detection method for odd aberrations of the projection objective lens of a lithography machine according to claim 1, it is characterized in that the process of determining the sensitivity coefficient S of odd aberrations comprises the following steps: ① Select one of the Zernike coefficients Z _k and the value x of the corresponding Zernike coefficient, and use the lithography simulation software to simulate and gradually obtain the Zernike coefficient Z according to the selected series of defocus positions _k Next series of imaging position simulation offset (Δx _i , Δy _i ); ② Using the imaging position simulation offset ( _Δxi , Δy _i ), calculate the odd aberration sensitivity coefficient S _i according to S _i = _Δxi /x, where i and k are positive integers greater than or equal to 1. 3. The in-situ detection method for odd aberrations of the projection objective lens of a lithography machine according to claim 1, wherein a series of defocus amounts of the substrate (7) carried by the workpiece table (8) are near the focal plane Within the selected defocus range, the number of several defocus values at intervals of a certain defocus step amount should be greater than 4. 4. The in-situ detection method for odd aberrations of the projection objective lens of a lithography machine according to claim 1, wherein the mask test mark includes a group of horizontal dense lines and a group of vertical dense lines, and the mask test mark The period is the same as the alignment mark period used by the optical alignment system. 5. The in-situ detection method for odd aberrations of the projection objective lens of a lithography machine according to claim 1, characterized in that the number of the mask test marks is 5 or more, and they are evenly distributed in the exposure field of view .

Images