TW544766B - Method for fabricating phase shifting mask of photolithography process - Google Patents

Abstract

First of all, a substrate applied in the lithography process is provided, and then a high transmission attenuate layer (HTAL) is formed on the substrate. Then an opaque layer is formed on the high transmission attenuate layer (HTAL). A photoresist layer is formed on the high transmission attenuate layer (HTAL) to expose a first phase region and a second phase region. Afterward, the opaque layer is etched to define a first phase region and a second phase region on the high transmission attenuate layer (HTAL). Subsequently, a photoresist layer is formed on the second phase region and the opaque layer to expose a partial surface of the high transmission attenuate layer (HTAL) that is located the first phase region. Then the partial surface of the high transmission attenuate layer (HTAL) that is located on the first phase region is etched through until a predetermined depth in the substrate. Finally, removing the photoresist layer is to form a phase shifted region in the etched region and a phase unshifted region in the unetched region, whereby a phase shifting mask that can make uniform exposure intensity is obtained by this invention.

Description

544766 V. Description of the invention (1) 5-1 Field of the invention: The present invention relates to a method for forming a phase shift mask for a lithography process, and more particularly to an optical lithography process using a high penetration weakening layer. The method of strong phase shift mask. 5-2 Background of the Invention: With the increasing accumulation of semiconductor devices, such as Metal-Oxide-Semiconductor (MOS) devices, in order to keep the area of the chip (ch ip) the same, or even shrink, to continue to reduce The only way for the unit cost of the circuit is to continuously reduce the design rule of the circuit to meet the future development trend of the high-tech industry. Therefore, the space area occupied by the components also follows the circuit design specification (des 丨 叩 ru 1 e) and gradually shrink. With the development of semiconductor technology, the size of integrated circuit components has been reduced to the sub-micron range. When semiconductors are continuously scaled down to the deep sub-micron range, some problems in process scaling occur. In order to build very small active components on the wafer surface, the impact of these effects must be limited to small, well-defined areas. In complementary metal-oxide-semiconductor devices, the lithography (1 i thography) technology in the manufacture of very large integrated circuits is a process that converts the opening pattern to a light-sensitive polymer (commonly called photoresist). Defines the microstructure of silicon-based materials that are changed by the special effects of a series of process steps.

544766

V. Description of Invention (2) Domain. The manufacture of complementary metal oxide semiconductor wafers includes pattern transfer of repeated resistance, followed by etching, ion implantation, deposition, or other Y effects, and ends with removing the consumed photoresist for use in the next 2 repeating New photoresist layer in process sequence. The basic lithography system includes two light sources, a printed template or a mask containing a pattern to be transferred to the wafer, a set of lenses, and a device for aligning the pattern on the mask with the pattern of the wafer. Because a wafer containing more than 50 to 100 crystal strips (d 丨 es is one to four crystal strips (dies) at a time for pattern transfer = es), the stepper is a Rayleigh (Ray丨 eigh) equation is bounded by Quan Wei's as follows:

R = kl X λ / NA where is again the wavelength of the light source projected on the system, and NA is the projected numerical aperture. {^ 1 is a factor that combines the analytical limit of the theory that can be used in micro-systems. The standard exposure system is reduced from 0.8 to 0.5. In optical lithography, steppers with wavelengths of 193, 2 48, 3 5 6 nm are currently widely used. The traditional photomask contains a chrome pattern on a quartz plate, allowing light to pass through the place where the chromium is removed. ◦ Light of a specific wavelength is projected through a mask onto a photoresist coated on the wafer. The chrome pattern is removed from the mask and exposed on the photoresist. Exposing the photoresist to an appropriate wavelength will cause the molecular structure of the photoresist to be modified and changed. The photoresist polymer allows the developer to chemically

First, the description of the invention (3) The method decomposes and removes the photoresist on the exposure system to allow the unexposed photoresist to develop:. On the 2nd ground, the negative photoresistor can be imagined as each independent. The helmet can be opened after the cover is irradiated (the point is limited by the clean area, and the light source can be controlled by). These traditional photomasks are either closed (points covered by chromium, glass; COG) or one-called chrome on the glass (Chrome step function only has accurate == ary) light cover. Perfect square shape At any distance, such as the theoretical limit of the wafer surface. Tilt in limited image with matte. The relatively small radiation effect will cause the image to appear printed on the opposite side; the I / NA is small, and the size, distance, and the constructive addition of the image size and distance V: nearby shadows ^ ^ are not completely dark, Instead, it presents a light intensity of 5 intensity curves between features. In contrast, the interaction of the neighboring features of the exposure system shows that the first resolution is limited to the projected light image, that is, the intensity difference between the dark features of the neighboring shells. Lai Qiangeng i TA is an increase in the dark area. Finally, the intensity of the shadow is not hanging. It is printed as a combined structure. Yin: 1? The quality can be copied in lithography, which mainly depends on The latitude of exposure in clothing can be reduced; that is, the tolerance of the exposure and the change in focal length will still get the correct image size. As design features become smaller and smaller, all Lithography Resolution Enhancement Techniques (LRET) in principle use an alternating phase photomask (Alternati ^

Phase Mask), also known as Phase Shifted Mask 544766 V. Description of the Invention (4)) This is a '-equivalent transfer pattern. The phase parameter improves the third parameter of the lithography process. The phase with the magnitude and the square quantity can also change the path of the mask material. The light passing through the mask will have an inversion of 180 degrees, which is just the opposite. The method that makes this effective is to provide nearly twice the exposure latitude of the analytical SMfted Mask micro- $, or by introducing a lower kl value of light. The electric field vector is oriented in the same direction as any vector, so in addition to changing the amplitude of the electric field, it shifts the direction of the beam by correcting the change in the beam line i to phase. By recessing the mask into a thinner part and the light passing through the thicker part of the mask: that is, the electric field vector will be equal in size but will be completely offset after the interference of the direction 1 beam. The traditional photomask is a reticle, which is usually called COG or Eryang Yuancheng Chengli ’s optical circuit with a chrome film. It is produced by the optical lithography process. In general, good lithography technology will usually provide improved solutions = size will usually be reduced. Resizing and electromagnetic radiation act on the mask j degree, 14 produces the smallest shrinkable mask ... Good usually contains phase Si domain = light or some parts are phase shifted. / 、 The process of some opening masks on the first mask has improved a lot in the resolution of the phase shift mask technology. Therefore, the fabrication of photomasks today is difficult: lithography solution. . However, strong phase-shifted light? It is best that the strong phase-shifted light is a regular and repetitive graph t, = there may not be enough space in the hood design ^ The contraction of the rule of f makes the light u "from the phase-shifted light Hood technology. Page 9 544766 V. Description of the invention (5) ___ No matter what, it is difficult to produce a uniform exposure mask in the traditional process. In addition to the difficulty of making the photomask, the most important subject two is subject to different penetration intensities on the wafers. What's more, He She first contributed to the above reasons, and we need a method for forming a photomask. In order to improve the yield of subsequent processes: ::: shift 5-3 The purpose and summary of the invention: In the background of the produced f: ^, the traditional photomask manufacturing method has problems in the process. The present method can be used to overcome the traditional system. One of the objectives of the present invention is to improve the general strong phase shift mask by forming a high penetration attenuation layer (HTAL). Take this. The same exposure intensity is obtained in the phase shift region. Based on this, yield. In addition, because of the present invention, the method can save process costs. Therefore, the method of the present invention provides a kind of penetration energy (High can reduce the phase shift. The method of the present invention can achieve easy and can form a strong phase shift mask unevenness phenomenon. The transmission non-phase shift zone of the present invention Exposure source of strong G can simultaneously improve the production process. 7 Compatible with the traditional process, it is economically efficient. Applicable to deep sub-micron technology. Page 10 544766 5. Description of the invention ( 6) Medium 0

According to the above-mentioned object, the present invention discloses a method for forming a strong phase shift mask for a lithography process. In one embodiment of the present invention, a substrate for a lithography process is first provided, and a high penetration reduction layer (HTAL) is formed on the substrate. Then, an opaque layer is formed on the high penetration reducing layer (HTAL). Second, the opaque layer is etched to define a first phase region and a second phase region on the high penetration weakening layer (HTAL). Next, a photoresist layer is formed on the second phase region and the opaque layer, and a part of the surface of the high penetration reduction layer (HTAL) located in the first phase region is exposed. Thereafter, a portion of the surface of the high penetration weakening layer (HTAL) located in the phase shift region is etched to a predetermined depth inside the substrate. Finally, the photoresist layer is removed to form a phase shift region in the etched region and a non-phase shift region in the non-etched region. Thereby, a phase shift mask having a uniform exposure intensity can be formed. Detailed description of 5-4 inventions:

The present invention is directed to a method for manufacturing a strong phase shift mask for forming an optical lithography process. In order to fully understand the present invention, detailed steps will be proposed in the description of the following II. Obviously, the implementation of the present invention is not limited to the specific details familiar to those skilled in semiconductor manufacturing. On the other hand, well-known components or process steps have not been described in detail to avoid unnecessary limitations of the present invention. The preferred embodiments of the present invention will be described in detail as follows. However, in addition to these detailed descriptions, the present invention can also be

Page 11 544766 V. Description of the invention (7) It is widely implemented in other embodiments, and the scope of the present invention is not limited, which is subject to the scope of subsequent patents. Referring to FIG. 1A, in one embodiment of the present invention, a substrate 100 for optical lithography mask manufacturing process is first provided. The material of the substrate includes a transparent material, such as ,quartz. Then, a FAW first weakening layer (HTAL) 1 110 is formed on the substrate 100, and a high penetration weakening sound (htAL) 1 1 0 is formed by a deposition process, for example, a chemical vapor deposition method ( Chemical Vapor Deposition; CVD), and the material of the high penetration weakening layer (HTAL) 11 0 further includes a high penetration phase shift material, such as' Ta a S i / 3 0x, where the high penetration weakening layer (HTAL) The transmittance can be adjusted by the percentage of the component when it is deposited. Next, an opaque layer 120 is formed on the high penetration reducing layer (HTAL) 110, wherein the opaque layer 20 further includes a chromium layer (Chromium; Cr). Referring to FIG. 1B, in this embodiment, a first / photoresist layer 140 is formed on the opaque layer 120, and a first phase region 150A and a second phase region 150B are defined. . Then, the first photoresist layer is used as an etching mask to perform a first etching process of 160 to etch the opaque layer ι 2 and form a first phase region 15 (^ and a second phase region 1508). On the high penetration weakening layer (11 丁 人 1 ^) 11〇, where the first first etching process 160 includes a dry etching process. After removing the first photoresist layer 140, a second photoresist is formed. The layer 17 is on the second phase region 150 and 8 and the opaque layer 120, and exposes a part of the surface of the high penetration reduction layer CHTAL) 11 on the first phase region 1508, as shown in the first c figure. Show.

544766 V. Inventive Words (9) Purpose of Benefit. Therefore, the method of the present invention is simple and applicable to deep submicron technology. For the deep sub-micron process, this method is a better method for forming a strong phase shift mask for an optical lithography process. Of course, the present invention may be applied to any photolithography process, as well as any semiconductor process. Furthermore, the present invention has not been developed for use in forming a strong phase shift mask by forming a high penetration weakening layer.

Disgracefully, according to the description in the above embodiment, the present invention may have many positive and negative differences. Therefore, it needs to be understood within the scope of the appended claims. In addition to the above detailed description, the present invention can be widely implemented in other embodiments. The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the patent application of the present invention; all other changes or modifications that do not depart from the spirit disclosed by the present invention shall be included in the following patent applications Within range.

Page 14 544766 Brief Description of Drawings Figures A through E are schematic cross-sectional structure diagrams of a phase photomask for forming an optical lithography process according to an embodiment of the present invention. Main notice [5 points representative symbol

10 0 110 12 0 140 1 5 0A 1 5 0B 16 0 1 70 1 80 1 90A 1 90B Substrate high penetration weakening layer opaque layer No. photoresist layer No. 2 mesh area No. 1 first etching process No. Phase shift region and non-phase shift region in the second etching process of the two photoresist layers

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Claims (1)

544766 VI. Application Patent Scope 1. A method for forming a phase shift mask in an optical lithography process. The method for forming a component of the optical lithography process includes the following steps: providing a photomask substrate; forming a penetration reducing layer on On the photomask substrate; forming an opaque layer on the penetration reducing layer; touching a part of the opaque layer to form a first phase region and a second phase region on the penetration reducing layer; And etch through a part of the surface of the penetration reducing layer located in the first phase region up to a predetermined depth inside the light-transmitting substrate to form a phase shift region in the first phase region and a non-phase shift region In the second phase region. 2. The method for forming a phase shift mask in the optical lithography process according to item 1 of the scope of the patent application, wherein the material of the aforementioned mask substrate includes a light-transmitting material. 3. The method for forming a phase shift mask in the optical lithography process according to item 2 of the scope of the patent application, wherein the light-transmitting material further includes a quartz material. 4. The method for forming a phase shift mask in the optical lithography process according to item 1 of the scope of the patent application, wherein the material of the above-mentioned penetration reducing layer includes a highly penetrating phase shift material. 5. Phase of the optical lithography process as described in item 4 of the scope of patent application Page 16 544766 VI. Method for forming a patented shift mask, wherein the above-mentioned highly penetrating phase shift material further includes a Ta a S / 5 Ox 〇 6. The optical micro-device as described in the first patent scope A method for forming a phase shift mask in a shadow process, wherein the method for forming a penetration reduction layer described above includes a deposition process. 7. The method for forming a phase shift mask of the optical lithography process according to item 6 of the scope of the patent application, wherein the above-mentioned deposition process includes a chemical vapor deposition method. Phases of the process of making shadows, micro-science, the description of light, including the more transparent layer of light on the 1st paragraph, the law of the law, please apply for the form of the cover • Mask 8-light shift layer each of the middle circle The law-makers specially requested to apply the form of the hood 9 _ The process of light shifting phase shadowing microscopy The description of the rate of refracting material is η Long wave C light = ί D: It is determined by λ The phase formula is Φ 7Γ Cheng Xifang Φ column, which is borrowed from the bottom and middle, it is 3 degrees} deep -1 fixed η pre / (λ Desc cm-1 Covers with wrap-around method under the step series. “The light path of the base material is transparent to make a shadow for micro-lifting. The upper part of the upper layer is weaker and the light is less transparent. Layer light transmission and penetration is not high ^ 1 Page 17 544766 VI. Applying the special brake range, the opaque layer is formed to form a first phase region and a second phase region on the south penetrating weakening layer to form a photoresist layer on the second phase. Area and the opaque layer, and is exposed on a part of the surface of the high penetration weakening layer of the first phase area; a photo-engraving process is performed by using the photoresist layer as an overprint mask to pass through the first A portion of the surface of the high penetration weakening layer in a phase region reaches a phase depth in the transparent substrate; and removing the photoresist layer to form a phase shift region in the first phase region The non-phase shift region is in the second phase region. 11. The method for forming a phase shift mask in the optical lithography process as described in item 10 of the scope of the patent application, wherein the material of the high penetration reduction layer further includes a TaaSi / 30x. 12. The method for forming a phase-shifting photomask in the optical lithography process according to item 10 of the scope of patent application, wherein the opaque layer includes a chromium layer. 13. The method for forming a phase shift mask in the optical lithography process as described in item 10 of the scope of patent application, wherein the above-mentioned etching process includes a dry etching process. 1 4. The method for forming a phase shift mask in the optical lithography process as described in item 10 of the scope of patent application, wherein the phase depth is determined by the following equation: D = (Φ / 2 7Γ) X [ λ / (n-1)], where Φ is Page 18