TW535212B - Method of correcting photomask patterns - Google Patents

Abstract

A photomask pattern including at least a line pattern is provided. An endcap is formed on the line pattern, the endcap being adjacent to an end portion of the line pattern. The endcap and the line pattern define a profile for a word line. An auto optical proximity correction (auto-OPC) program is performed to modify the line pattern excluding the end portion of the line pattern.

Description

535212

FIELD OF THE INVENTION The present invention is to provide a method for correcting a mask pattern, in particular to modify a contour of the end of a mask pattern. Background Description In semiconductor manufacturing, in order to integrate circuits The patterns of circuits) are smoothly transferred to the semiconductor wafer. The circuit patterns must not be counted on a photomask layout, and then a photomask is produced according to the photomask pattern output from the photomask layout. The pattern on the photomask is transferred to the semiconductor wafer at a certain ratio. Because the critical dimension (CD) of the pattern that can be made on the reticle is limited by the resolution limit of the optical exposure tool, it follows the integration The circuit patterns are designed to be smaller and smaller. When these high-density mask patterns are subjected to an exposure process for pattern transfer, it is easy to produce an optical proximity effect (OPPE). For example, right-angled corner rounded, line end shortened, and line width increase / decrease are common mask patterns caused by optical proximity effects. defect.

535212 V. Description of the invention (2) In order to avoid the distortion of the mask pattern transfer caused by the optical proximity effect, the current solution is to use computer aided design (CAD) to automatically perform the mask layout. Optical proximity correction (auto-OPC) to eliminate the optical proximity effect, and then make a mask based on the modified pattern. Please refer to FIG. 1 and FIG. 2. FIG. 1 and FIG. 2 are schematic diagrams of a conventional method for performing mask pattern correction on a mask layout diagram 10 using an automatic optical proximity correction program. As shown in FIG. 1, the mask layout 10 includes a plurality of linear mask patterns 12 for defining a character line pattern, and the character line pattern 1 is used to form a character line mask (not shown) ) To transfer the word line patterns 12 to a semiconductor wafer (not shown). Among them, the method for transferring the word line pattern 1 on the semiconductor wafer uses a conventional technique such as yellow light and etching. Since the technology of yellow light and etching is not the focus of the present invention, it will not be repeated here. In addition, in order to illustrate the relative positions of different mask patterns, the mask layout diagram 10 further includes a diffusion region pattern 14 for defining a doped region or a diffusion region such as a source electrode and a non-polar electrode. A diffuse area mask (not shown) can be made by turning out, and then the yellow area and the doping technology can be used to transfer the diffuse area pattern 14 to the above-mentioned semiconductor wafer. Among them, the word line pattern 12 and the diffuse The area where the area pattern 14 overlaps may be defined as an active gate, and the active gate and the diffusion regions 14 on both sides thereof may be defined as an active ar.ea 16.

535212 V. Description of the invention (3) As shown in Figure 2, in order to avoid the optical proximity effect, when performing the character line pattern 12 correction, the automatic optical proximity correction program will use the correction factors set in the program, including exposure, development, Process parameters such as etching, and graphic parameters such as the width and length of the character line and the distance between the plurality of character lines, calculate the parts of the character line pattern 12 that need to be modified, such as the line edge of the character line 12, At the end of the line (line end) and corner (corner), etc., the character line pattern 12 is modified according to the calculation result to obtain a character line correction contour 18. In order to avoid the subsequent yellow light and the etching process causing the length of the character line pattern 12 to be excessively reduced, which affects the range of the active area 16. Therefore, in the above-mentioned correction process, the automatic optical proximity correction program usually uses the character line pattern 1 2 An end cap 18a having a width greater than the line width of the character line is formed at the end region to compensate for the loss that may occur in the process of the end of the character line. Because the optical proximity effect may cause the pattern to have different degrees of error depending on the shape of the character line pattern 12 and the surrounding pattern of the character line pattern 12, the character line correction formed by the automatic optical proximity correction program is used. Over contouring may cause problems with overcorrection. Still as shown in FIG. 2, suppose that the extended lengths of the modified contours 18 of different character lines outside the active area 16 are the correction parameters a and b, respectively, because the correction parameter b is limited by two relative character line patterns 1 2 The distance has a correction value of a certain size. In contrast, because the correction parameter a does not have a limit on the distance between surrounding patterns, it may cause excessive expansion. Therefore, the end pattern 1 8 a is excessively extended, resulting in a character line diagram.

Page 6 535212 V. Description of the invention (4) Case 1 2 overlaps with the diffused area pattern 14 in areas other than the active area 16 and causes problems such as leakage current. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for correcting a mask pattern, so as to avoid the problem of over-correction of the mask pattern and affecting the quality of circuit components. In a preferred embodiment of the present invention, a mask pattern is first provided, and the mask pattern includes at least a linear pattern. Then, an end pattern is formed above the linear pattern, the end pattern is close to the end of the linear pattern, and the end pattern and the linear pattern form a word line outline. An automatic optical proximity correction program is then performed to correct the non-terminal area of the linear pattern. Since the present invention separately forms the end contour of the character line and the contour of the non-end region of the correction character line, and the end contour of the character line is separately formed above the original linear pattern, when the non-end region correction of the linear pattern is subsequently performed It does not include the correction of the contour of the end of the character line. Therefore, the present invention can precisely control the size of the contour of the end of the character line, thereby completely avoiding the problem of excessive correction of the end area of the mask pattern and improving the quality of the circuit element.

Page 7 535212, description of the invention (5) For detailed description, please refer to Figure 3 and Figure 4 for the mask pattern and mask layout. Figure 20 contains the mask pattern 22 to the mask pattern, and the diffusion region pattern of at least one diffusion region. • Sub-line photomask (not shown: on the chip (not shown), and diffuser (not shown) to put on the expansion sheet. In addition, the linear pattern can be defined as an active gate, defined as an active area 26 The less one of the corrections in Figure 3 is used to determine 24. It is >> to show the scatter plots and the scatter plots in Figure 22 and the active method to define the 'linear pattern in the sense source' 1 4 cases 1 4 Turn diffusion area gate pole # tolerance map. As shown in the figure = the character line pattern and the dopant pattern such as the drain electrode 22 is used to transfer 22-is used to make-moved to the above-mentioned half pattern 24 overlapping its two sides The diffused linear light area or the semiconductor area of the semiconductor diffused area may be formed at the end of the pattern 2 2 with a mallet case 28 next to the end profile. The near correction method (manual) light automatic optical connection Form a line graph at the modified end of the invention Domain Jin (hammer is formed in the end diagram of the line diagram, and the approach is close to the correction plan. The other rounds of the amendment are implemented: correction, that is, in the line diagram J 22 :: the shape of the end pattern 28, and the other end 22a. In addition, the case 28 can use any sense element line ^ including the near-correction program or temple of the auto-optical optical interface I. Then, as shown in Figure 4, the edge of the C pattern 22 is corrected: Medium 'To control the line width of the character line. This J T, the above-mentioned automatic optical proximity correction process

535212 V. Description of the invention (6) When correcting the line width of the linear pattern 22, it can also include the correction of the corners and ends of the linear pattern 22. Because the end pattern 28 provides the correction of the end area of the character line, and the linear pattern correction contour 30 provides the correction of the line width portion of the character line, the end pattern 28 and the line pattern are used when making the character line mask. The correction contour 30 must be outputted together to form a complete character line pattern. And when the end pattern 28 is formed, the size of the end contour of the character line can be adjusted according to the position of the active area 26, so the character line pattern can be completely avoided from being over-corrected with the diffusion area pattern 24 outside the active area 26 Generate overlap. Compared with the conventional mask pattern correction method, the present invention uses two optical proximity corrections to form the character line end contour and the non-terminal region contour of the character line, respectively. Above the original linear pattern, and subsequent correction of the line width and corner of the linear pattern, this character line end contour correction is not included, so the size of the character line end contour can be precisely controlled, and the characters can be completely avoided. The problem of excessive correction of the end region of the line mask pattern improves the quality of the circuit components. The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the scope of the patent application for the present invention shall fall within the scope of the invention patent.

535212 Simple illustration of the diagram Simple illustration of the diagram Figures 1 and 2 are schematic diagrams of a conventional method for correcting a mask pattern. 3 and 4 are schematic diagrams of a method for correcting a mask pattern according to the present invention. Explanation of Symbols 10 Mask Layout Figure 12 Character Line Pattern 14 Diffuse Pattern 16 Active Area 18 Character Line Correction Outline 18a End Pattern 20 Mask Layout Figure 22 Line Pattern 22a Line Pattern End 24 Diffuse Pattern 26 Active Area 28 end pattern 30 linear pattern correction contour a 'b correction parameter

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Claims (1)

535212 VI. Scope of patent application 1. A method for correcting a photomask pattern on a photomask layout, the photomask layout includes a linear pattern and a diffusion area pattern, and the linear pattern and the The area where the diffusion pattern overlaps is defined as an active gate. The method includes the following steps: performing a first predetermined form of optical proximity correction (0PC), and line end of the linear pattern ) To make corrections and avoid overlapping of the linear pattern and the diffusion pattern in areas other than the active gate; and perform a second predetermined form of optical proximity correction to correct the non-end regions of the linear pattern. 2. The method of claim 1, wherein the linear pattern is formed on a first photomask to form a word line pattern on a semiconductor wafer, and the diffusion region pattern is formed on a A second photomask for forming the diffusion region pattern on the semiconductor wafer. 3. The method according to item 1 of the scope of patent application, wherein the first predetermined form of optical proximity correction is to form another end pattern above the linear pattern, the end pattern is close to the end of the linear pattern, and the end The pattern and the linear pattern form a character line outline. 4. The method of claim 3, wherein the end pattern includes a hammer head shape pattern. 535212 6. Application for Patent Scope 5. The method of the first scope of patent application, wherein the second predetermined form of optical proximity correction includes the correction of the edge of the linear pattern (1 ineedge) to control the critical dimension of the linear pattern. , CD). 6. A method for correcting a mask pattern, the method comprising the following steps: providing a mask pattern, the mask pattern including at least a linear pattern; forming an end pattern above the linear pattern, and the end pattern is immediately adjacent to the The end of the linear pattern, and the end pattern and the linear pattern form a sub 70 line, and an automatic optical proximity correction program is performed to correct the linear pattern. 7. The method according to item 6 of the patent application range, wherein the automatic optical proximity correction program corrects a non-terminal region of the linear pattern. 8. The method according to item 6 of the patent application range, wherein the automatic optical proximity correction program includes a correction of an end region of the linear pattern. 9. The method of claim 6 in which the end pattern includes a mallet-shaped pattern. = 1 0. The method according to item 6 of the patent application scope, wherein the linear pattern is used to define a character line. Page 12 535212 6. Scope of patent application 1 1. The method of item 10 of the scope of patent application, wherein the size of the end pattern is determined according to the position of the active area of the character line.