TW575903B - Adjusting method of phase-match mapping in lithography process - Google Patents

Description

575903

This book is about a lithography process to adjust the matching mapping in the lithography process, and in particular, it is about a kind of lithography process that is undoubtedly very important in the manufacturing process of semiconductor integrated circuits. As a result, our company can accurately define the designed pattern on the photoresist layer through this process.% The pattern of the photoresist layer is transferred to the semiconductor substrate by the etching process, and the required circuit structure. Generally speaking, the lithography process mainly includes priming, photocoating (coating), pre-baking (or soft baking), exposure, post-exposure processing, development, and hard baking, etc. Several steps. Its -2, the resolution of the exposure process (resoiution) is good, especially the component accumulation. Whether it is a key factor for further improvement, all major semiconductor manufacturers have invested heavily in research and development to seek higher levels. From the analysis of optical principles, the resolution of the exposure machine is proportional to the wavelength of the light source used, that is, the shorter the wavelength of the exposure light source, the smaller its resolution. In terms of the current commercial semiconductor process, the exposure machine has evolved from using light sources with wavelengths such as 436nm (g-line) and 365 (i-line) to 248nm using sub-wave 1 eng th. Light sources in the deep UV range, or even shorter wavelengths, in response to increasing demand for component accumulation. Today's lithography technology has overlay specifications to ensure that different film layers can be stacked (matched) well. There are two main factors for stacking errors, one is the error of the optical projection system, and the other is the error of the stacking of the mask to the mask. At present, the difference between the reticle and reticle error is only calculated by adding reference marks to the periphery of the pattern area and the prohibited area of the reticle.

0503-7672TWf; TSMC2001-0972; YCCHEN.ptd page 4 575903

Figure 1 shows a conventional mask with a reference mark, which forms a pattern area on a mask substrate 10 ', such as quartz glass, such as a mask composed of a chromium (Cr) metal layer. pattern. Numeral 14 is a prohibited article, and there must be no pattern on it. The reference mark 1 6 is added to the periphery of the prohibited area. The reference mark 6 is used to calculate the overlap between the photomask and the photomask = error. For example, it is used to calculate the photomask defining the active area pattern and define the gate. The error of overlap between the masks in the f 'case. Figure 2 shows the overlap error between the two photomasks obtained by using the above reference standard, which is based on a 2 7 χ 2 7 array. "'No.' Figure 3 shows the digital representation of Figure 2 The error of the overlap between the two photomasks is in nanometers. Figure 34 shows the error in the γ direction, and the error in the direction. From Figures 2 and 3, it can be seen that the above method in the prohibited area cannot accurately represent the photomask. For the error between the masks, in addition, Figure 4 shows that the other two masks overlap each other: 'In the area labeled 20, there is a certain tendency, and the error is small in the central part. In order to solve the above problems, the purpose of the present invention is to adjust the matching mapping method in order to use the error data of the ancient and / or lithographic interlayers. Read ^ Accuracy of a single pair of photomasks. The method includes the following steps. First, a mask and a pattern area are provided. Next, a white M mask is provided in one of the pattern areas. Then, the coordinates of the reference mark are obtained as the reference value of the reference mark. Finally, the reference mark is removed. ^ The application of the matching mapping Matches Ming adjustment method of mapping to the lithography process

^ / 5903 Explanation of the five inventions (3) Obtain the error data of the high accuracy of the two precise light stars. You can use this magnification and reduction amount, the block rotation of the optical projection system, and the above optical The change in the projection r's degree of crossover and offset. By correcting the error, the addition of the number :: can effectively compensate for the yield of the two thin layers on the wafer. The yield rate of the addition process is continued. The method of adjusting the matching mapping is described in detail in the following example. Mask beauty ^ 1: Baixian, as shown in Figure 5A, is provided with a -mask, such as the -Yuzhuo substrate 100, for example The county sf ^ area 102, for example, is a chromium (Cr) public residence (quartz) glass, forming a pattern forbidden area ... incomplete mask pattern. The reference number 104 is with a clip test; the Λ pattern. On the periphery of the forbidden area 104 is ς ^ ° 06. It is shown that 108 is one of the blocks in the pattern area 102. The picture is an enlarged view of the β "丄 block 108, where the number 110 is an opaque pattern and the number 112 is a transparent blank area. Next, please refer to FIG. 5C, and add a reference mark Gan,:, and a photoresist layer (not shown) in the blank area 112. The shielding layer may be a chrome metal layer. Cheng Yi: Two-implementation of the photoresist layer with a reference f t: pattern-beam exposure and development μ. The photoresist layer after the 'm' is used as a mask, and the masking layer is etched to transfer the pattern of the photoresist layer to the masking layer. Finally, the photoresist layer is removed to complete the production of the reference mark 114. Fig. 5D shows the method of Fig. 5C in which several reference marks 11 4 are added to the pattern area 102.

575903 V. Description of the invention (4) 俨 卞: 5 Take the coordinates of all the reference marks 1 1 4 of the child. Use the coordinates of these reference beams to obtain the final mask room. The iron beams show the π gate difference Beco 0 1 .. Ming 4 ..., 5 £: Picture, remove the reference mark in the blank area 112: A cover layer 12 is formed on the substrate 100 to expose the reference mark, and the reference mark 114 is removed by a post-cut process. In this way, all reference marks U4 in the pattern area 102 in FIG. 5D are removed. _ f Resurrection method can form a reference mark in the pattern area of another photomask ^ 4 Ϊ Serve the coordinates of the reference mark on it. Then, the two masks ^ ^ ^ ° can be used to obtain the negative accuracy of the mask-to-mask overlap error that is not accurate. The reference area f Si? Is a comparison of the measured data obtained from the conventional method and the pattern :: i 二 ί: 1 ... jin in this embodiment. * The figure can be used to obtain the high-accuracy mask-to-mask door error data. Canzhuang Jiyou soaps and hoods are hunted by the umbrella to obtain the accuracy of the surface @ You can use this high accuracy time ... error data, block rotation ,; poor material t correction optical projection system area , Coordinate 糸 degrees 篁, orthogonal degrees and offset dan i. By modifying the parameters of the above-mentioned optical projection system, it is possible to convert = layer overlap ... difference, such as the method of the present invention; take the == difference data of the overlap between the mask of the patterned mask and the mask of the gate electrode, and then By using these error data to calculate the parameters of the error optical projection system and system by software, it is possible to effectively compensate the errors of the overlap between the moving poles.勒勒 & and gate Figure 7 shows an example using the implementation / Friends

575903 V. Description of the invention (5) Schematic diagram of the effect. In the figure, the four points A, β, c, and D are located outside the mask pattern, and their overlapping errors are 100 nm, E, and! ^ Points are located inside the mask pattern. The pair error is 50nm. If only four points a, B, C, and D are measured and corrected by 0.8 ppm to reduce the residual error from 100n ^ to 4 n ^, however, this correction makes the residual error at points E and F from 50nm increased to 82nm. If this implementation is used, the method measures six points A, B, C, D, E, and F and corrects 0.5 ppm to reduce the remaining errors of A, B, C, and D from 100nra to 40nm, E and? The dot residual error increased from 50 nm to 70 nm. Therefore, using the compensation of this embodiment to compensate for the error of the overlap between the two photomasks' as described above can reduce the error in the pattern from 82nm to 70nm. The materials used in ί ::: f are not limited to those cited in the examples, but are replaced by various materials and forming methods with appropriate characteristics, and the structural space of the present invention is not limited to the scales cited in the examples. Although the present invention has been disclosed as above with the preferred embodiments, it is appropriate to make the present invention. Anyone who is familiar with this skill, * do not depart from = limit can be changed and retouched within the range. Therefore, the husband X, n ^ enclosing the stubborn princes is defined by the scope of the present invention. The field of protection of the present invention is subject to the scope of the patent application attached to the eyes.

575903 Brief description of the drawings In order to make the above-mentioned objects, features, and advantages of the present invention more comprehensible, the preferred embodiments are described below in detail with the accompanying drawings as follows. Figure 1 shows a conventional mask with reference marks. Fig. 2 shows the overlap error between the two photomasks obtained by using the above reference marks. Figure 3 A shows the error in the Y direction. Figure 3B shows the error in the X direction. Figure 4 shows the overlap error between the other two masks. Figures 5A to 5E show the manufacturing method of the embodiment of the present invention. Figures 6A and 6B are comparisons of the measured data obtained by adding a reference mark to the pattern area using a conventional method and this embodiment. Fig. 7 is a schematic diagram illustrating the effect achieved by the method of this embodiment. Explanation of symbols 10, 100 ~ photomask substrate; 12, 102 ~ pattern area; 1, 4, 104 ~ forbidden area; 1, 6, 10, 1 1 4 ~ reference mark; 108 ~ pattern area 102 One block; 110 ~ opaque pattern; 112 ~ transparent blank area; 120 ~ cover layer; 20 ~ block.

0503-7672TWf; TSMC2001-0972; YCTHEN.ptd page 9

Claims (1)

6. Scope of Patent Application 1 · One step in the lithography process: The method of adjusting matching mapping includes providing a photomask, obtaining the reference mark in the pattern area and the photomask having a pattern area; inserting in a blank area A reference mark; write down the coordinates as a reference for adjusting the matching mapping value The phase adjustment in the photolithography process described in item 1 of the mapping 3 patent scope is <Wanfa, where the reference mark is a chrome metal layer. The step of adjusting the phase in the photolithography process described in the first scope of the patent 4 shots 11: the step of removing the reference mark, including the step of engraving Γίίί to form a cover layer and exposing the reference mark; And eclipse the reference mark. The method of adjusting the phase-contrast method in the photolithography process as described in item 1 of the scope of the patent application is to adjust the phase-to-phase method and the water-t method. It also includes using the coordinates of the reference mark obtained to overlap the mask before the mask. Error data. As described in Item 5 of the stated patent scope, the method of adjusting coincidence in the lithography process also includes using the obtained mask to overlap the masks ^ ^ to correct the block rotation of the optical projection system. The amount of reduction is measured by the coordinate system, orthogonality, and offset. 575903 6. The scope of patent application for screening is the method of adjusting the phase error in the lithography process described in item 5 of the project. It also includes the use of the obtained masks to overlap the masks and the difference between the masks. In order to compensate for the overlap error between the two thin film layers on the wafer. 8 · —A method for adjusting matching mapping in a lithography process, including: a first photomask provided with a first pattern area; ^ in a first blank area of one of the first pattern areas Insert a first reference mark Lu Ji, ， to get the seat of the first reference mark; provide a second photomask, the photomask has a second pattern area; a second blank area in one of the second pattern areas Insert a second test mark in;, do not obtain the coordinates of the second reference mark; ^ 〃 use the obtained coordinates of the first and second reference marks to obtain the first and second masks to the mask Overlapping error data; and removing the first and second reference marks. 9. The method for adjusting matching mapping in the lithography process as described in item 8 of the scope of patent application, wherein the first and second photomasks have a photomask substrate made of quartz glass. 'I 0 · The method of adjusting the matching mapping in the lithography process as described in item 8 of the scope of the patent application, wherein the first and second reference marks are chrome metal layers. II · The method of adjusting matching mapping in the lithography process as described in item 8 of the claim range, wherein the step of removing the reference mark further includes the following steps: forming a mask layer on the photomask to really expose the reference Mark; and dumplings 0503-7672TlVf; TSMC2001-0972; YCCHEN.ptd 11th buy 575903 Mark to remove the reference mark. The phase error data in the photolithography process described in item 8 of the wm screen is adjusted to rely on the use of the obtained photomasks to overlap the photomasks, and the production of the projection system. Changes in block rotation, zoom in and out, orthogonality, and offset. Screening 2: As Fang Shen: Special: Adjusting the phase and time of photolithography in the photolithography process described in item 8 of the scope Overlap error between two thin film layers on a circle. 14. · The following steps for adjusting the matching mapping in the lithography process: 広 has been provided to provide a photomask, the photomask has a pattern area;. Find a blank area in the pattern area; and form on the photomask A masking layer; defining the masking layer using a lithographic engraving process to reference a mark in the blank area; obtaining the coordinates of the reference mark as a threshold value for adjusting a matching map; and removing the reference mark in a clever way. 15. The method for adjusting matching mapping in a lithography process as described in item 14 of the scope of the patent application, wherein the photomask has a photomask substrate made of quartz glass. '16. The method for adjusting matching mapping in a lithography process as described in item 14 of the scope of patent application, wherein the shielding layer is a metal-clad layer. 1 7 · Adjust the phase in the lithography process as described in item 14 of the scope of patent application W5903 Method of mapping: Steps of removing the reference mark further include forming a mask layer on the mask and exposing the reference mark; and removing the reference mark at a later time. .18. As described in item 14 of the scope of the patent application, the soft phase matching of bismuth in the lithography process + + * ^ you are neat and correct, and it also includes using the obtained reference mark to Obtain the error data of the reticle-to-reticle overlap. It is known that the method of I 专利 in the lithography process as described in item 8 of the scope of patent application, t includes using the obtained mask to overlap the mask and difference data to correct the optical projection system. Block rotation, zoom in and out, coordinate system measurement, orthogonality and offset change. ， 2 〇 · The method of adjusting the phase and mapping in the lithography process as described in item 18 of the scope of the patent application, further including using the obtained error data of the σ overlap between the photomask and the photomask to compensate the crystal Overlap error between two thin film layers on a circle. And 0503-7672TlVf; TSMC2001-0972; YOCHEN.ptd