TW416092B - Mask capable of increasing line width resolution and production method therefor - Google Patents

Abstract

The invention relates to a mask with increased resolution of line width and its production method therefor, in which materials with penetration rate roughly 100%, such as quartz, are utilized to form mask substrate. Further use the material with penetration rate roughly 0%, such as the Cr film of the Binary Intensity Mask (BIM) to form the dense pattern area and use the material with penetration rate in between 5% and 30%, such as the MoSiON film of the Attenuated Phase Shift Mask (APSM) to form sparse pattern area. Therefore, the resolution of the dense pattern area and Depth Of Focus (DOF) of the sparse pattern area can be both taken into account. Besides, the sparse pattern area can provide a mask bias to further improve the acquired aerial image and DOF.

Description

416092 Five 'invention description (1) " " " " The present invention relates to a photomask and a method for manufacturing the same, and more particularly, to a photomask capable of improving line width resolution and a method for manufacturing the same, A photomask substrate is formed using a material having a light transmittance of approximately 100%, and a dense pattern region is formed on a surface of the photomask substrate by using a material having a light transmittance of approximately 0%, and a light transmittance between 5% and 30 is used. The material between% forms a sparse pattern area. In the semiconductor process, 'the tools required for photoresist exposure on the wafer surface are in addition to a light source' and a photomask for providing a circuit pattern for performing pattern transfer. Figure U is a cross-sectional view of a conventional Binary Intensi ty Mask (BIM). As shown in the figure, the substrate of the binary mask is composed of flat and transparent quartz 10, and the semiconductor elements (the patterns of each layer are coated on the surface of the quartz 10 with an opaque network with a thickness of about several hundred angstroms). The film 12 is shown. In addition, in order to prevent reflection of the metallic chromium film 12 during exposure, the surface of the chromium film 12 may be further covered with a layer of chromium dioxide film 14 having a thickness of about 200 angstroms, as shown in FIG. 1B. However, taking the design of line width 0.18um as an example, the binary mask can only provide a depth depth of focus (DOF) of 0.6um, which cannot be applied to mass production. Therefore, some people are in binary Scattering bar or Assistant feature is added to the reticle, using optical proximity correction technology (Optical

I

Proximity Correction (〇PC) in order to improve the line width difference (CD difference) between the sparse pattern area and the dense pattern area and increase the focal depth of the sparse pattern area to 0.8um . Because the focal depth of the dense pattern area will be greater than the focal depth of the sparse pattern area ’

P.4 1609292 5. The main concept of the invention (2) method is to adjust the original sparse pattern area to a semi-dense pattern area using the addition of scattering lines to obtain a better focal depth. . However, this method will also increase the mask manufacturing complexity, which affects Mask inspection and Mask repair, and is still insufficient when applied to the next-generation process. Therefore, ‘some people have proposed to replace the binary mask with an Attenuated Phase Shift Mask (APSM)’ and use its Edge Contrast enhancement to improve focal depth. The so-called attenuating phase shift mask is to directly define the pattern of the opaque area with a phase shift layer with a light transmittance of about 5% to 30%, and use the phase shift layer to generate the positive and negative phases during (exposure) Interference, so that the image pattern projected by the exposure machine (Stepper) on the wafer has better resolution. Take the design of line width 0.18um as an example, when the light transmittance is 5%, there is no scattering rod The depth of focal length can be increased to 0.7um, and the depth of focal length with a scattering rod can be further increased to 0.9um. Figures 2A and 2B are sectional and top views of the attenuation phase shift mask. As shown in the figure As shown, the attenuated phase shift mask includes, from bottom to top, a quartz layer 20 'made of quartz whose light transmittance is generally 100%. Mo'SiON is made of MoSiON whose light transmittance is generally 5-30%. Layer or CrF layer 22 'and a chromium layer 24 made of chromium (cr) with a light transmittance of substantially 0%. A chromium layer 24 with a light transmittance of substantially 0% is formed at the edge of the pattern so that light does not penetrate this Area, however, the increase in Background Transmittance and Proximity Effect And it will cause contrast resolution dense pattern area (Re so 1 u t i on) decreased 'attenuated phase shift such that light

Page 5 416092 V. Description of the invention (3) The mask cannot be used to figure out the dense pattern area (Dense Pattern), that is, a very large numerical aperture (NA) is used. In addition, the inspection and repair of the attenuation phase shift mask is also very complicated. ^ In view of this, the main object of the present invention is to provide a photomask capable of improving the line f resolution and a manufacturing method thereof, which can simultaneously take into consideration the focal depth depth of the sparse pattern area and the line width resolution of the dense pattern area. In order to achieve the above and other objectives, the present invention provides a photomask manufacturing method capable of improving line width resolution, which mainly uses a material C (such as quartz) having a light transmittance of approximately 10 形成 to form a photomask substrate; and The surface of the cover substrate is made of a material with a light transmittance of approximately 0% (such as the chromium film of a binary photomask) to form a dense ξ pattern area, and a material with a light transmittance between 5% and 30% (such as MoSiON film of an attenuated phase shift mask) forms a sparse pattern area. In this way, the resolution of the dense pattern area and the focal depth of the sparse pattern area can be taken into consideration. In addition, the sparse pattern area can also have a mask difference to further improve the obtained image distribution and focal depth. In addition, the present invention also provides a photomask capable of improving line width resolution, and f has a photomask substrate. The photomask is formed using a material with a light transmittance of approximately 100% (such as Shiyang); a uniform dense pattern area is provided on the photomask substrate. The surface is made of a material with a light transmittance of approximately 0% (such as the chrome film of a binary photomask); and a sparse pattern area 'on the surface of the photomask substrate' uses light transmittance between 0% and 2 5 % '' 'Material (such as the "film" of the attenuation phase shift mask). In addition, the sparse pattern area can also have a mask difference to further improve the obtained image distribution and focal depth. To make the above and other objects, features, and advantages of the present invention clearer

______ 5. Description of the invention (4) 'Easy to understand' The following is a detailed description of a preferred embodiment and the accompanying drawings, as follows: Brief description of the drawings Figure 1A is a traditional binary photomask Sectional view; Figure 1B is a sectional view of Figure 1A plus an anti-reflection layer; Figure 2A is a sectional view of a traditional attenuation phase shift mask; Figure 2B is Figure 2A attenuation phase shift Top view of a photomask; FIG. 3 is a top view of a photomask capable of improving line width resolution according to the present invention; and FIG. 4 is a flow chart of manufacturing a photomask capable of penetrating line width resolution according to the present invention. The embodiment overcomes the problems that the binary mask cannot provide sufficient focal length depth in the sparse pattern area and the attenuation phase shift mask cannot provide sufficient resolution in the dense pattern area. The present invention combines the binary mask in the dense pattern area The high-resolution and attenuated phase shift mask has the advantages of high focal length depth in the sparse pattern area to form a mask. In this type of mask, the pattern of the dense pattern area is formed using a chromium film with a light transmittance of approximately 0%, and the pattern of the high-resolution 'sparse pattern area with a binary mask is made using the light transmittance between Phase shift layers between 5% and 30% form a 'high focal depth with an attenuating phase shift mask. Read and refer to FIG. 3 'This is a plan view of a photomask capable of improving line width resolution according to the present invention. As shown in the figure, the photomask of the present invention is divided into a sparse pattern area A (I so 1 a t ed Pa 11 ern Reg i on) and a dense pattern area B (Dense

416092 V. Description of invention (5) ‘

Pattern Region). In order to improve the focal depth, the pattern of the sparse pattern area A (such as the attenuation phase shift mask shown in Figures 2A and 2B) is composed of a phase shift layer (such as MoSi ON) with a transmittance between 5% and 30% Layer) is formed on the surface of a photomask substrate (such as a quartz layer) having a transmittance of approximately 100%. In addition, in order to improve the resolution, the pattern of the dense pattern area B (such as the binary mask shown in Figs. 1A and 1B) is formed by an opaque layer (such as a chromium film) with a light transmittance of approximately 0%. On the surface of a photomask substrate (such as a quartz layer) with a transmittance of approximately 100%. With the above structure, the photomask capable of improving the line width resolution of the present invention can take into account both the focal depth of the sparse pattern area and the resolution of the dense pattern area. In addition, in order to further improve the obtained image distribution (Aerial Image) and focus (distance from depth), the present invention can also apply a mask difference (Sketch Bias) in the sparse pattern area. As for the conventional method of setting a scattering rod in the mask, It increases the complexity of photomask manufacturing and affects the inspection and repair of photomasks, so it is no longer necessary. Figure 4 shows the manufacturing flow chart of photomasks that can be line-width-resolved according to the present invention. In STEP1, a mask substrate is provided by using a material (such as quartz) whose light transmittance is generally im. Then, in step STEP2, the surface of the mask substrate is formed with a dense pattern area such as chrome, And the use of the time between the material and secret) to build ΓίΓ in 5% cloth (Aerial Image) and focal depth. . The transmitted image is divided into a design with a line width of 0.18 u m as an example. With this type of mask without a diffuser, the focal depth is improved to more than 0.8um and dense.

Page 8 41609 ^ _____ V. Description of the invention (6) The graphics in the pattern area can also be clearly analyzed. In addition, the proximity effect from the pattern density (Pattern Dens 1 ty) l: 1.2 to isolation can also be maintained in a small state. Furthermore, this method can extend the phase shift layer to a very high light transmittance without being limited to the conventional range of 5%. In summary, the present invention provides a photomask capable of improving line width resolution and a manufacturing method thereof, which can simultaneously take into account the focal length depth of a sparse pattern area and the line width resolution of a dense pattern area. Although the present invention has better defined the present invention's' any familiarity with this technique and scope 'as a modification and the scope of the patent application appended to Envision, the examples are disclosed above, but it is not intended to be an artist' Without departing from the spirit of the present invention, the scope of protection of the present invention shall prevail.

Page 9

Claims (1)

416092 VI. Application for patent scope 1. A method of forming the mask on the light material through a light-transmitting mask 2. Rushen mask manufacturing method 3. Rushen mask manufacturing method 4. Rushen mask manufacturing method MoSiON ° 5 Such as the cover manufacturing method difference (Mask 6.-one by one by one by the surface of the board by one by one & read the substrate Table 7 · Rushen cover, which can improve the linear luminosity of the substrate cover density The patent mask of the substrate mask of the pattern mask is patented, among which the patent is patented, among which is patented, among which is patented, among which is Bias). The sparseness of the light transmittance interface in the case area which can improve the line transmittance, the light transmittance, and the dense area. The patent discloses a method for manufacturing a mask with a wide transmittance, including: forming the mask with a material of 100%. The substrate 'on the surface' with a material-shaped area with a light transmittance of generally 0%; and the surface 'with a sparse pattern area α with a light transmittance between 5% and 30%. For wide-resolution light, the material whose transmittance is approximately 100% is quartz. The light that can improve the line width resolution as described in item 1 The material whose light transmittance is substantially 0% is chromium. The light that improves line width resolution as described in item 1 The light transmittance between 5% and 30% is the light that is used to improve line width resolution as described in item 1 The sparse pattern area of the mask A mask with a resolution of the screen is applied, including a substrate made of 100% material; a body made of 0% material and formed on the base; and between 5% and 30% Made of materials and forming a pattern area. The material for improving line width resolution described in item 6 is generally 100% quartz. No. 10 I 416092 6. Scope of patent application 8. As described in item 6 of the scope of patent application, the mask capable of improving line width resolution, wherein the material having a light transmittance of substantially 0% is chromium. -9. The mask capable of improving the line width resolution as described in item 6 of the scope of patent application, wherein the material having a light transmittance between 5% and 30¾ is MoSiON. \ 1 0. The mask capable of improving line width resolution as described in item 6 of the scope of patent application, wherein the sparse pattern area further has a mask difference (Mask Bias) α