TW542942B - Method to repair attenuation type phase shift mask - Google Patents

Abstract

The present invention discloses a method to repair an attenuation type phase shift mask, wherein an opaque layer is deposited on the phase shift layer around the translucent region of contact hole on the mask to repair the pinhole defect position. Finally, form a concave groove with 180 DEG phase angle on the substrate of the translucent region of contact hole, so as to improve the phase shift characteristics of mask.

Description

542942 V. Description of the Invention (1) Field of the Invention: The present invention relates to a process technology of a semiconductor integrated circuit element, and particularly to a defect of a repair attenuate phase shift mask (APSM) ( defects). Relevant technical description: In the manufacturing process of semiconductor integrated circuits, the lithography process occupies a very important position. With this process, we can accurately define the design items on the photoresist layer / then The pattern of the photoresist layer is transferred to the semiconductor substrate using the remaining process to produce a desired line: structure. -Generally speaking, the lithography process mainly includes several steps, such as priming coating, pre-baking (or soft baking), exposure (exp ·) processing, development, and hard baking. Among them, the exposure program K = = Uti〇n) good insight into whether the degree of component accumulation can be further improved-all major semiconductor manufacturers have actively invested in research and development to achieve higher costs. From the analysis of the wave, the shorter the resolution of the exposure machine and the wavelength of the light source used, that is, the wavelength of the exposure light source, the analysis is: "industrialization" conductor process, the exposure machine source has evolved to use 248nm or less Light sources in the same wavelength range of light, in response to the element's accumulation degree :, Evening light wide: uv) As the size of the element will continue to shrink, the photomask: as small as two, the effect of the light diffraction effect will be greater than the main = Ai It is more obvious that

542942 V. Description of the invention (2) The photoresist layer in the non-j light zone has also undergone a number of reductions in light intensity (contrast), and it is also recognized that the% exposure is converted into an exposure pair for the purpose of experience. The development step proceeds. : The exposure area can still be kept under bright light when it is zoomed out. Good contrast, there are _ species of lettuce _ hh p AA j, non-exposed first & ri j developed from the phase shift type of A contrast, such as Figure 丨 shows an attenuated phase shift mask patterned with a contact hole pattern using the flying mask technology. Below the contact hole, please refer to Figure 1. The symbol 10 shown in the figure indicates a transparent Quartz 'light transmittance is approximately = 0: not = a patterned phase shift layer with a specific diffraction index (phase S 1. er), meaning the transparent area of the contact hole of the photomask is 100. Moreover, No.

1 5 represents the mask layer of JB ,, r- Ijb, and JU that is composed of metal. This area cannot pass the exposure light source of the lithography process. Once it is detected that the above phase shift pattern has defects, the entire phase shift mask must be scrapped, and this is not very cost effective. Therefore, there is a need to develop a method for repairing the defects in the phase shift pattern of the phase shift mask. When a pinhole defect is generated on the light reduction phase shift mask, an opaque material is deposited for repair to prevent light from penetrating through the pinhole defect. 1 & 1 et al. Disclosed in US Patent No. 6, 〇16,357 on January 18, 2000 a feedbac [i method to repair phase shift mask], which has defects in transmission Aeriai image analysis results of the phase shift mask for repair.

Yang et al. Announced U.S. Patent No. 6, 1 1 4, 0 73 on September 5, 2000

542942 V. Description of the Invention (3) ~ — Lizhong discloses a method for removing opaque pollutants on a photomask by using a focused ion beam method.

Baum et al., U.S. Patent No. 6,159,641, published on December 12, 2000, disclose the use of a reactive gas to deposit an opaque repair material on the defect of a photomask. However, “the traditional repair method of a light-reducing phase-shifting photomask that touches a hole”, a defect is formed on the photomask, and an opaque material is directly deposited for repair. However, the repairing material is opaque and cannot provide the function of a phase shift layer. Therefore, the repaired photomask functions like a traditional dual intensity mask and does not have a phase shift effect.纟 The analysis of the patched area on the same mask is worse than that of the unpatched S-field, which has a heavy impact on the "process window" in the "system". In view of this, in order to solve the above-mentioned problem, the present invention has two main methods for repairing the attenuation phase shift mask, which can make the mask still provide a 180 degree phase shift in the contact hole area. First, the summary of the invention: The purpose of the present invention is to provide a method for reducing the A-then-the original% of the light% shift mask. 31 ::: J :::: Repairing the attenuation phase First, provide an attenuation type Phase shift mask dagger-patterned phase shift layer, the above phase "yes"-a light-transmitting substrate and an I-phase shift layer are provided on the surface of the light-transmitting substrate

0503-7728TW; TSMC200M596; 1597; Felicia. Page 6 542942

Surface, and the surface of the transparent substrate has a contact hole transparent region in the patterned phase shift layer, wherein the patterned phase shift layer around the contact hole transparent region has a damage defect. Then, an opaque layer is formed in the patterned phase shift around the transparent area of the contact hole to repair the damaged defect position. Finally, a part of the transparent substrate in the transparent region of the contact hole is etched to a certain depth to form a transparent substrate region with a phase angle of 180 degrees. According to the concept of the present invention, the light-transmitting substrate of the light-transmitting area of the contact hole is etched to form a groove with a phase angle of 180 °, and the groove may be located in the center of the light-transmitting area of the contact hole or at the center of the light-transmitting area of the contact hole. Around the frame of the contact hole light transmitting area. As mentioned above, the material of the light-transmitting substrate is, for example, quartz glass, and the light transmittance is about 100%. The material of the patterned phase shift layer, such as oxynitride (MoSiON), has a transmittance of about 6% and a phase angle of 180 °. As described above, the step of forming the above-mentioned opaque layer includes: depositing an opaque layer in the presence of a hydrocarbon-containing gas or a carbon-containing gas using a -focus ion beam method. Among them, the above-mentioned hydrocarbon-containing gas system is styrene gas. As described above, the light-transmitting substrate in which the light-transmitting area of the contact hole is etched uses XeFz as an auxiliary gas and the focused ion beam method is used to complete the etching. Example: The flow chart of the process of repairing the photomask according to the first embodiment is to explain one of the present invention. Please refer to FIG. 2A to FIG. 2C and FIG. 3A to FIG.

542942 V. Description of the invention (5) First, please refer to FIG. 2A to provide an attenuation phase shift mask 30 suitable for exposing a contact hole pattern on a wafer. The attenuation phase shift mask 30 is composed of a transparent substrate 300 and a patterned phase shifter 302. The phase shift layer 302 is disposed on the surface of the transparent substrate 300, and The photomask 30 has at least one contact hole transparent region 601, 602 in the patterned phase shift layer 3 02. When an exposure light source is provided, the light source can pass through the contact hole light-transmitting regions 60 1 and 60 2 to form a contact hole pattern. However, the photomask is liable to be damaged like a pin hole during use. For example, the patterned phase shift layer 3 2 around the transparent area 6 0 2 of the contact hole has a damage defect. As for the contact hole, The light-transmitting area 6 〇1 remains normal without damage defects. The material of the translucent substrate 300 is, for example, quartz glass, and its transmittance is about 100%. The material of the patterned phase shift layer 3 02 is, for example, vermiculite oxynitride (MoSiON), and its transmittance is about 6%, which can provide a phase shift with a phase angle of about 180 degrees. For the sake of clarity, please refer to the top view of the photomask in FIG. 3A, which can clearly show the difference between a contact hole transparent area 601 that maintains normal and no damage and a contact hole transparent area 602 with broken defects. Next, please return to the cross-sectional view of the process and refer to FIG. 2B, which is a cross-sectional view showing the subsequent steps of FIG. 2 A, forming an opaque layer 3 〇3 around the above-mentioned transparent area 6 0 of the contact hole. The patterned phase shift is 3 2 0 to repair the σ defect position. Can use a commercial mask repair machine, for example

Micrion's focus ion beam maehine is in a carbon-based gas or a hydrocarbon-containing gas

542942 V. Description of the invention (6) In the presence of (hydrocarbon-containing gas), an opaque layer 303 made of, for example, an organic polymer is deposited on the above-mentioned patterned phase shift layer 302 at the location of the damage defect, so that it is repaired. The contact hole light-transmitting area 6 〇 2 a has been exposed successively, and the imaging size on the wafer or other substrate is equal to the size of the normal non-defective contact hole light-transmitting area 601. The hydrocarbon-containing gas is, for example, a styrene gas. Then 'Please refer to FIG. 2C'. This step is mainly to engrav the light-transmitting substrate 300 of the repaired contact hole light-transmitting area 602a to a predetermined depth to form a groove I with a phase angle of 180 ° as described above. The center of the contact hole light-transmitting area 602a. The method of engraving the substrate 3 0 is to use the above-mentioned focused ion beam machine ′ of M i c r ο η and use XeF2 as a gas assistance etching (AGE) for etching. Wherein, the remaining depth of the light-transmitting substrate 300 varies with the exposure light source wavelength to adjust the phase shift to 180 °. For example, when the light source wavelength used during exposure is 248 nm, the light-transmitting substrate 30 The depth of the engraved depth of 0 is about 2 2 0 to 2 4 5 nm; and when the wavelength of the light source used during the exposure is 193 nm, the #etched depth of the above-mentioned transparent substrate 3 0 0 is about 1 50 to 1 90 nm . In this way, the repair process of the attenuation phase shift mask 30 is completed. 0 Please refer to FIG. 3B, which is a top view showing the repaired mask 3 0, and the repaired contact hole transparent area 6 0 2 a is number 3 0 3 shows a patched opaque layer, and the light source can penetrate this area. The center of the contact hole transparent area 602 is a groove I with a phase of 180 degrees to provide a phase shift effect, so that the repaired contact hole transparent area 602a has a contact hole transparent area without damage. The exposure results of 601 are the same, with the same depth of focus (depth 〇f

0503-7728TWF; TSMC200M596; 1597; Felicia.ptd Page 9 542942 V. Description of the invention (7) focus 'DOF' and resolution (res0iUfi0n), and its process window is equivalent. Example 2 In the following, please refer to the flowchart of the repair mask process in FIGS. 4A to 4C and the top views of the mask process in FIGS. 5A to 5B to illustrate a preferred embodiment of the present invention. First, please refer to FIG. 4A, and provide an attenuation phase shift mask 40 suitable for exposing a contact hole pattern on a wafer. The attenuation phase shift mask 40 is composed of a transparent substrate 400 and a patterned phase shift layer 402. The phase shift layer 40 is disposed on the surface of the transparent substrate 400. In addition, the photomask 40 has at least one contact hole light transmitting area 800m and 802 in the patterned phase shift layer 402. When an exposure light source is provided, the light source can pass through the contact hole transparent areas 801 and 802 to form a contact hole pattern. However, 'the photomask is liable to be damaged like a pinhole during use', for example, the patterned phase shift layer 402 around the above-mentioned contact hole light-transmitting area 80 2 has a damage defect, and the above-mentioned contact hole is transparent Area 〇1 remained normal without damage defects. The material of the light-transmitting substrate 400 is, for example, quartz glass', and its transmission is about 100%. The material of the patterned phase shift layer 402 is, for example, molybdenum silicon nitride oxide (MoSiON), and its transmittance is about 6%, which can provide a phase shift with a phase angle of about 180 degrees. For the sake of clarity, please refer to the top view of the photomask in FIG. 4A, which can clearly show the difference between a contact hole transparent area 801 that maintains normal and no damage and a contact hole transparent area 802 with broken defects .

542942

Next, please return to the cross-sectional view of the process and refer to FIG. 4B, which is a cross-sectional view showing the subsequent steps of FIG. 4A. An opaque layer is formed in the patterned phase shift 4o2 around the transparent area 802 of the contact hole. To repair the above-mentioned damaged defect locations. A commercially available mask repair machine can be used, such as

Micri ^ n's focus ion beam machine (focus i〇n beam machine), in the presence of a carbon-based gas or hydrocarbon-containing gas (hydrocarbon-containing gas), deposit a material such as The opaque layer 403, which is an organic polymer, is at the position of the damaged defect of the patterned phase shift layer 402, so that the repaired contact hole transparent area 802 & size and the normal non-damaged contact hole transparent area 801 size is equal. The above-mentioned fe-containing gas is, for example, a styrene gas. Then, please refer to FIG. 4C. This step is mainly to etch the transparent substrate 400 of the transparent contact area 802a, which has been repaired, to a predetermined depth, and more to form a groove with a phase angle of 180 degrees. Π around the outer frame of the contact hole light-transmitting area 802 &. The substrate 400 is etched by using the above-mentioned MicrOn's focused ion beam machine 'and using XeF2 as a gas assistance etching (AGE) for etching. The etching depth of the light-transmitting substrate 400 varies with the exposure light source wavelength to adjust the phase shift to 80 °. For example, when the light source wavelength used during exposure is 248 nm, the The etching depth is about 220 ~ 245nm; and when the wavelength of the light source used in the exposure is 193nm, the above-mentioned transparent substrate 400 has an etching depth of about 150 ~ 190nm. In this way, the repair of the attenuation phase shift mask 40 is completed. < Advantages of the invention:

542942 V. Description of the invention (9) Please refer to Figure 5B, which is a top view showing the repaired mask 4 〇 The top view of the repaired contact hole transparent area 802a shows a repaired / transparent layer, light source Can penetrate this area. The outer periphery of the contact hole transparent area 602 is a 180 degree phase groove Π to provide the effect of phase shift, so that the repaired contact hole transparent area 802a has no damage from normal. The exposure results of the transparent area 801 of the contact hole are the same, with the same depth of focus ((1 邛 讣 of focus; DOF) and resolutin), and the process window is equivalent. /, 4 Figure 6A Fig. 6B shows the photomask (curve B) using a complete mask (curve A), repaired by the conventional method of deposition (best focus) and def0cus, respectively, and according to the present invention. The result after exposure of the repaired mask (curve C) is shown in Fig. 6a. The curve ◦ has the largest slope, so the mask according to the present invention can expose a scene with better contrast (contrast) image. It can be seen from FIG. 6B that the critical dimension (CD) of the photomask repaired by the conventional deposition method is reduced, and the CU of the photomask repaired according to the present invention is equivalent. The conventional repairing first mask technology can be seen. Will cause the CD to shrink, making the process capacity = multiple fill mask technology, available The better exposure image is ~ s CD, so it will not cause the process tolerance to be reduced. Features and advantages of the invention, such as =, are characterized by the use of a conventional mask repair machine, such as ^, ion beam machine, The defects on the surface are impervious to deposition, and after repairing, the function of replacing the phase shift layer is etched in the light-transmitting area.

542942 V. Description of the invention (10) Refer to FIG. 4 ′, which shows the results of the electric field amplitude intensity and image light intensity after exposure of the original mask and the mask according to the conventional method and the repair method of the present invention. To sum up, the method of repairing the attenuated phase shift mask of the present invention has the following advantages: 1. Compared with the conventional repair method, according to the repair method of the present invention, the line width of the exposure pattern can be narrowed, thereby improving the resolution ( resolution) 2 · Complete repair of root platform 3 · Similar shadows (depth 〇 Complemented light The spirit and scope of the present invention The scope of protection of the present invention is supplemented according to the present invention, there is no need to follow the image of the present invention, maintaining the f focus cover will not affect In a wider range, within the scope of Dangdang, the D0D attached to the back is similar to the D0F attached to the back. It is good to know how to implement the application, and the steps are simple, the optical characteristics after exposure, examples, and resolution. (Reso continues the example of the lithography process as disclosed above. This artist, ^ 's changes and the patented scope of the patent, easy to control can provide the original mask, such as: focus depth lution), so modify the parameters. However, it is not intended to be limited without departing from the scope of the present invention, so the intent of the present invention shall prevail.

542942 Brief description of the drawings -------- "To make the above-mentioned object of the present invention" The features and advantages are more obvious and understandable. The following exemplifies a preferred embodiment in conjunction with the drawings. The detailed description is as follows: FIG. 1 shows a conventional attenuation phase shift mask for defining a pattern of a contact hole on a wafer. Figures 2A to 2C are process flow diagrams according to a preferred embodiment of the present invention. 3A to 3B are top views showing a photomask according to a preferred embodiment of the present invention. 4A to 4C are flowcharts showing a process according to another preferred embodiment of the present invention. 5A to 5B are top views showing a photomask according to another preferred embodiment of the present invention. Figures 6A and 6B show the mask (Curve B) and the mask (Curve B) which have been repaired by the conventional ^ product method under the best focus (best focus) and defocus, respectively. / L (curve C) repaired according to the method of the present invention is the result after exposure. $ 卓 Symbol description: 10, 300, 400 ~ transparent substrate; 20, 302, 402 ~ patterned phase shift layer (phase Shihe 100, 601, 602, 801, 802 ~ transparent area of contact hole; '3 0, 4 0 ~ attenuation phase shift mask; 15 ~ light-shielding layer; 601, 801 ~ normal contact hole light transmission area

542942 Schematic description of 602 and 802 ~ transparent areas of contact holes with defects; 60 2a and 80 2a ~ transparent areas of contact holes with repaired opaque layer; 303 and 403 ~ opaque layers; I, II A groove with a phase angle of ~ 180 degrees.

0503-7728TWF; TSMC2001-1596; 1597; Felicia.ptd p. 15

Claims (1)

542942 1 · A method for repairing an attenuated phase shift mask, the above-mentioned attenuated shift mask is suitable for forming a contact hole, and includes the following steps:-An attenuated phase shift mask having a transparent substrate and a patterned phase [The phase shift layer is disposed on the surface of the light-transmitting substrate, and the surface of the light-transmitting substrate has a contact hole light transmitting area in the patterned phase private layer, wherein a patterned phase shift sound around the light transmitting area of the contact hole Has a broken defect; that is, forming an opaque layer in a patterned phase shift around the transparent area of the contact hole to repair the damaged defect position; and etching a part of the transparent substrate in the transparent area of the contact hole to a certain extent Depth 'to form a transparent substrate region with a phase angle of 180 degrees. 2. The method for repairing an attenuated phase shift mask as described in item 1 of the scope of patent application, wherein the light-transmitting substrate is made of quartz glass. 3. The method of repairing the attenuation phase shift mask as described in item 1 of the scope of the patent application, wherein the light transmittance of the transparent substrate is about 100%. 4. The method of repairing the attenuation phase shift mask described in item 1 of the scope of the patent application ', wherein the patterned phase shift layer is composed of molybdenum silicon nitride oxide (MoSiON). 5. The method of repairing an attenuation phase shift mask as described in item 1 of the scope of patent application ', wherein the transmittance of the patterned phase shift layer is approximately. 6. The method of repairing the attenuation phase shift mask described in item 1 of the scope of patent application ', wherein the phase angle of the patterned phase shift layer is 180 degrees. 7 · Repair attenuated phase shift light as described in item 1 of the scope of patent application 0503-7728TWF; TSMC2001-1596; 1597; Felicia.ptd 542942 The method of applying for the scope of patent application, JL φ flower; > The steps of coke ion beam and eight-forming into the above-mentioned opaque layer include ... using a pair of products f in the presence of a hydrocarbon-containing gas or a carbon-containing gas Shen 1 only returned the light layer. The repaired attenuated phase-shifted light body described in item 7 of the 8th patent of the mask. ', ^^ The ancient and idol of the styrene gas hood of the smoke gas system] The repair and decay phase shift light as described in the first item of the scope, as soon as possible. The light-transmitting substrate of the light-transmitting area of the contact hole at 1 minute was completed by a focused ion beam etching method. The 3 generations of the mask are repaired and attenuated phase shift light XpF and Huo 2 'as described in item 9 of the patent scope of the patent. Among them, the light-transmitting substrate engraved in the light-transmitting area of the contact hole uses XeF2 as an auxiliary gas to complete the etching . a ^ \ A method for repairing the attenuation phase shift mask, the above attenuation phase shift mask is suitable for forming a contact hole (^ M) into a contact hole, including the following steps: A light-transmitting substrate and a pattern are provided on the surface of the light-transmitting substrate, and the surface of the light-transmitting substrate has a contact hole light-transmitting area in the patterned phase-shifting layer. μ, +, u α Β ^ Υ 1 patterned phase shift layer around the transparent area of the contact hole Has a broken defect; 10%-an opaque layer in a patterned phase shift around the transparent area of the contact hole to repair the location of the broken defect; and etching a part of the transparent substrate in the transparent area of the contact hole to form A groove with a phase angle of 180 degrees is at the center of the light-transmitting area of the contact hole. 542942 VI. Applying for a patent —— # Wei Shishen's patent scope first mask method, Gan + must 'where the above-mentioned light transmission # stomach · such as the patent application scope of the first mask Fang Mu ei' Light transmission & stomach ^. As described in the first patent application method, method 'wherein the above pattern (MoSiON) is composed. Yikou 芊 15. Fang Mu ^.% As the first photomask of the scope of patent application. That is, the above-mentioned pattern 16. The method of the first photomask in the scope of patent application, wherein the repair attenuation phase shift substrate described in the above-mentioned pattern degree 01 is made of quartz glass. The light transmittance of the repaired attenuation phase shift substrate described in item 1 is about 1 Q ％. The repair attenuation phase shift phase shift layer described in item 1 is composed of molybdenum silicon nitride oxide. The light transmittance of the repair attenuation phase shift phase shift layer described in item 1 is about 61. The phase angle of the phase-shifted phase-shifted layer is approximately 8 〇 〇 I 2. The repaired attenuation phase-shift as described in item 1 of the scope of patent application:: Method 'wherein the step of forming the above-mentioned opaque layer includes: A focused ion beam method is used to deposit an opaque layer in the presence of a hydrocarbon-containing gas or a carbon-containing gas. ， 8 · The method for repairing the attenuation phase shift photomask as described in item 17 of the declared patent scope, wherein the above-mentioned hydrocarbon-containing gas system is styrene gas 0 1 9 In the method for repairing the attenuation phase shift mask, the light-transmitting substrate for etching the light-transmitting area of the contact hole is completed by using a focused ion beam I engraving method. 2 〇 · Phase repair phase shift as described in item 19 of the scope of patent application 0503-7728TW: TSMC200M596; 1597; Felicia.ptd, page 18, 542942 6. Method of applying a patent mask, in which the transparent substrate engraved with the above-mentioned contact hole light-transmitting area uses XeF2 as an auxiliary gas to complete the etching . A method for repairing an attenuated phase shift mask. The above-mentioned attenuated phase shift mask is suitable for forming a contact hole (conn tact hole), and includes the following steps: Provide an attenuated phase shift mask with a transparent Optical substrate and a patterned phase shift layer 'The phase shift layer is disposed on the surface of the transparent substrate, and the surface of the transparent substrate has a contact hole light transmitting region in the patterned phase shift layer', wherein the contact hole is transparent The patterned phase shift layer around the area has a damaged defect; forming an opaque layer in the patterned phase shift around the transparent area of the contact hole to repair the location of the damaged defect; The inner part of the transparent substrate forms a groove with a phase angle of 180 degrees around the outer frame of the transparent area of the contact hole. 22. The method for repairing an attenuated phase shift mask as described in item 2 of the patent application scope, wherein the transparent substrate is made of quartz glass. 23. The method for repairing an attenuated phase shift mask as described in item 21 of the scope of patent application, wherein the light transmittance of the light-transmitting substrate is about 100%. 24. The method for repairing an attenuated phase shift mask as described in item 21 of the scope of the patent application, wherein the patterned phase shift layer is composed of molybdenum silicon nitride oxide (MoSiON). 25. The method for repairing an attenuated phase shift mask as described in item 21 of the scope of patent application, wherein the transmittance of the patterned phase shift layer is about 6 M! 0503-7728TWF; TSMC2001-1596; 1597; Felicia.ptd page 19 542942 ~, 丨-application patent range one 26. The method for repairing the attenuation phase shift mask described in item 21 of the patent application range, where The phase angle of the patterned phase shift layer is about 180 degrees. 2 7 · The method for repairing an attenuated phase shift mask as described in item 21 of the scope of patent application, wherein the step of forming the opaque layer includes: using a focused ion beam method, in a hydrocarbon-containing gas or a In the presence of a carbon-containing gas, an opaque layer is deposited. 2 8 · The method for repairing an attenuation phase shift mask as described in item 2 of the scope of patent application, wherein the styrene gas in the above-mentioned hydrocarbon-containing gas system is used. '2 9 · The method for repairing an attenuated phase shift mask as described in item 21 of the scope of the patent application, wherein the transparent substrate for etching the transparent region of the contact hole is completed using a focused ion beam > 1 insect engraving method. 30. The method for repairing the attenuation phase shift mask as described in item 29 of the scope of the patent application, wherein the light-transmitting substrate for etching the light-transmitting area of the above-mentioned contact hole uses X e F2 as an auxiliary gas to complete | . 0503-7728TW; TSMC2001-1596; 1597; Felicia.ptd p. 20