TW561552B - Optical grading layer and its manufacturing method - Google Patents

Abstract

A kind of method of forming optical grading layer suitable for use on a substrate is disclosed in the present invention. The invention contains the following steps: forming a dielectric layer on the substrate, in which the dielectric layer contains an upper surface and a lower surface, and the lower surface has an interface with the substrate; and using a gas plasma containing oxygen atoms to process the dielectric layer, so as to form an optical grading layer that is used as an antireflection layer, and has an oxidizing reaction decreasing downwards from the surface during the oxidization procedure. The invention also includes an optical grading layer formed on a substrate and a dielectric layer containing an upper surface and a lower surface, in which the lower surface has an interface with the substrate. The optical grading layer is formed by using gas plasma containing oxygen atoms to process the dielectric layer, and is used as an antireflection layer, so as to have an oxidizing reaction decreasing downwards from the surface during the oxidization procedure.

Description

561552

FIELD OF THE INVENTION The present invention relates to a semiconductor lithography process, and more particularly to a lithography process = an anti-reflection layer. More specifically, it relates to a kind of light and a method for making the same. Background of the altar team. In the lithography process, in order to increase the resolution, the light source required for exposure is gradually reduced from G-line (wavelength 436 nm) and I-line (wavelength 365 nm) to less than 250 nm, such as deep Ultraviolet light argon fluoride (ArF) laser (193 nm) and vacuum ultraviolet light fluorine (I? 2) laser (157 nm). Since most substrates, such as highly reflective substrates, especially in the deep ultraviolet and vacuum ultraviolet light bands, have reflection problems that are larger than those in the visible light band, their guiding, standing wave effects and notches in the photoresist layer (n. The "tching" effect will be more serious, which greatly reduces the reliability of pattern transfer during the lithography process. In addition, because of the use of chemically amplified photoresistors in the production of deep ultraviolet light in this industry, this type of photoresist is very sensitive to small exposure changes. Therefore, how to make it in deep ultraviolet and vacuum ultraviolet light High-efficiency optical impedance reflective layers are very important. In order to improve the disadvantages mentioned above when lithography using low-wavelength light sources, especially for highly reflective substrates, many methods have been proposed. One of them is the bottom anti-reflection layer (BARC), which is widely used in the industry. It is mainly used to reduce the reflected light at the resist / substrate interface. Figure 1 is a cross-sectional view of a conventional anti-reflection structure at the bottom using an anti-reflection layer to improve the reflected light at the resist / substrate interface, where reference numeral 10 is a substrate, such as silicon or metal, with high reflection Substrate. To eliminate this height

〇522-8457TWF (N); dwwang.ptd Page 5 561552 5. Description of the invention (2) The reflective substrate generates light reflection during lithography, which causes the standing wave effect and the notching effect as described above. A surface of the substrate 10 is covered with a bottom anti-reflection layer 11, and then a resist layer 12 is coated on the bottom anti-reflection layer 11. In this way, during the lithography process, the presence of the bottom antireflection layer Η can cause the reflected light at the interface of the resist layer 1 2 / bottom antireflection layer 11 and the reflected light at the bottom antireflection layer 11 / substrate 10 interface to generate. Destructive interference can reduce the reflected light generated by the substrate 10 and avoid standing wave and notching effects that can affect the reliability of lithography. However, the above-mentioned conventional bottom anti-reflection layer usually includes only a single layer, and in order to make the reflected light at the interface of the resist layer 12 / bottom anti-reflection layer 11 and the reflected light at the interface of the bottom anti-reflection layer 11 / substrate 10 destructive. Interference, the thickness of the bottom anti-reflection layer 11 must be accurately controlled according to the wavelength of the incident light (not shown in the figure) and the refractive index of the bottom anti-reflection layer 11, but the substrate 10 often has various irregularities on the surface due to the factors of the previous process Phenomenon, and the thickness of the bottom anti-reflection layer 11 is changed due to the difference in position on the substrate 10, which is difficult to control. Therefore, the above-mentioned reduction of the reflected light generated by the substrate 10 is avoided to avoid affecting the reliability of lithography. The standing wave and notch effects are not as effective. In view of this, the bottom anti-reflection layer of a double-layer or multi-layer structure has been developed. For example, as shown in FIG. 2, the bottom anti-reflection layer 21 on the substrate 20 has five layers such as 21a, 21b, 21c, 21d, and 21e. In the bottom anti-reflection layer of the double-layer or multi-layer structure, the difference in optical properties between the layers is usually that the upper layer is a material with an extinction coefficient and a lower refractive index, and the lower the material, the extinction coefficient and refraction The larger the rate, the better the purpose of eliminating the reflected light in the lithography process. And the above two layers or more

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The anti-reflection film at the bottom of the layer structure has different optical characteristics, complexity, and cost. Too much, usually no larger than the purpose of the radiation layer must go through the process bar, so it also increases so in practical applications, all five layers. Changes in the components are achieved to achieve the process time and the number of layers produced by the process. One of the features of the present invention is to provide an optically graded layer and a method for manufacturing the same. Bottom: Anti-soil layer, get infinite multilayer optical gradient layer, its anti: 邛 anti-reflection from Miaocheng-▲ Dan Shen reflection effect is better than Chuanjiao

= The bottom anti-reflection layer is ㊣, and the process complexity is lower than the bottom anti-reflection layer of the H-layer structure, and the process time and cost are reduced. 0 Ganshe would like to use the out-of-light lithography process definition to be less than 180⑽ 'Α Reduces the uneven exposure in the resist caused by highly reflective substrates. Usually the bottom anti-reflection layer is a silicon oxynitride-based material, but these materials are baked after exposure in the lithography process (PEB). The alkaline substance is released during the step, which will destroy the resolution of the chemically amplified photoresist. If a single-layer organic bottom anti-reflection layer is used, new organic materials and processes for deep ultraviolet light must be developed. The second feature of the present invention is to provide an optically graded layer and its preparation method. A single-layer bottom anti-reflection layer is treated with a gas plasma containing oxygen atoms to obtain an infinite number of optically graded layers. The surface of the anti-reflection layer is modified, so that the optical gradient layer in the photolithography process is exposed during the post-baking step to 'reduce the release of diagnostic substances and avoid the resolution of the chemically amplified photoresist from being damaged. Brief description of the invention

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The object of the present invention is to provide an optically graded layer and a method for manufacturing the same. The bottom layer of a single layer is treated with a gas plasma containing oxygen atoms to obtain a multilayered optically graded layer. The bottom anti-reflection layer is better, and the process complexity is lower than that of the bottom anti-reflection layer for preparing a double-layer or multi-layer structure, and the process time and cost can also be reduced. Another purpose of the present invention is to provide an optically graded layer and a method for making the same ^ A single-layer bottom anti-reflection layer is treated with a gas plasma containing oxygen atoms to obtain an infinite number of optically graded layers while also resisting the bottom The surface of the reflective layer is modified, so that the optical gradient layer is baked in the photolithography process after the exposure step, reducing the release of alkaline substances, and avoiding the resolution of the chemically amplified photoresist. The method is suitable for forming a dielectric on the substrate, wherein the lower surface is an optically graded layer in which the dielectric is electropolymerized with the substrate gas to change the quality gradually. The present invention provides a method for forming a substrate, including the following steps: including an upper surface and a lower surface, an interface, and an oxygen-containing atom-forming layer as an anti-reflection layer, and the material is formed in another The invention further provides the above-mentioned method—an optically graded layer formed on a substrate, including: on the substrate, a surface and a lower surface are formed, the lower surface of the above and the substrate are formed by An optically-graded layer in which an oxygen atom gas plasma is used to treat one formed by the above dielectric as an anti-reflection layer, and the degree of oxidation is reduced from above. k the upper surface gradually downwards

561552 V. Description of the invention (5) " " '" ----- / Figure 3 shows the steps and structure of forming the optically graded layer in the preferred embodiment of the present invention. Said. Referring to FIG. 3A, the substrate 30 may be a metal or semiconductor substrate. For example, a broken substrate is formed with a thickness of about 15 nm to 100 nm, preferably about 30 nm, and the material may be nitride or carbonized. It is preferably a single-layer dielectric anti-reflection layer 31 made of silicon nitride oxide, carbon oxide, or a combination thereof. Then, a single-layer dielectric anti-reflection layer 31 is treated with a gas plasma 33 containing oxygen atoms, preferably a 20 plasma; wherein the power of the gas plasma 33 containing oxygen atoms / is set to 100 ~ 80 0 Watts, preferably 100 to 400 Watts' processing time is about 2 to 30 minutes, preferably 2 to 10 minutes; the processing depth can be 1 nm to 100 nm, depending on the single-layer dielectric The thickness of the anti-reflection layer 31 depends on the manufacturing process. By simply applying a simple plasma treatment step, the optically graded layer 34 shown in Fig. 3B can be obtained. Next, please refer to FIG. 4, which shows the change of the oxygen atom content along the line a, C in FIG. 3B in the preferred yoke example of the present invention. Among them, the vertical coordinate is the percentage of the content of oxygen atoms, which is indicated by a linear coordinate; the horizontal coordinate is the depth of the optical gradient layer 34, which is at the origin of point A, and the point b is about 30 cm in depth, and is indicated by a linear coordinate. Among them, in a preferred embodiment of the present invention, the oxygen atom content is gradually changed in a range of 3 to 10 nm in depth, and an optically graded layer with an equivalent number of layers can be obtained. Next, reference is made to FIG. 5, which shows the reflectance of the bottom anti-reflection layer before and after the plasma treatment at different wavelengths of the incident light of the lithographic light in a preferred embodiment of the present invention; The vertical coordinate is the reflectivity, which is indicated by a linear coordinate; and the horizontal coordinate is the wavelength of the lithographic incident light, which is indicated by a linear coordinate.

561552 V. Description of invention (6) No. Among them, especially under a light source having a wavelength of less than 200 nm, the reflectance of the optically graded layer 34 is much lower than that of the single-layer dielectric anti-reflection layer 31. ^ Please refer to FIG. 6, which shows a comparison of the single-layer dielectric = anti-reflective layer 31 as the single-layer dielectric = anti-reflective layer 31 in the preferred practical example of the present invention. At different baking temperatures T, the bottom anti-reflection layer and the optically graded layer 34 are used as the bottom L 射 f emissive layer, the ionic strengths released by the bottom anti-reflection layer are different. The vertical coordinate is the ionic strength (Α), which is indicated by a linear ^; the baking temperature (.0, is indicated by a linear coordinate. When used as the bottom anti-reflection layer, the ion f, & 10 1G A, especially at a general baking temperature of 90 ° C ~ 120. The ion intensity of the alkaline substance released from the bottom anti-reflection layer is much lower than that of the single-layer dielectric anti-reflection layer. The ionic strength of the alkaline substance released by the layer. ^ The present invention uses an optically graded layer in the form of an optically graded layer to make Λ outside reduction > The anti-reflection layer at the bottom of the resist. The f-forming method is to form a dielectric on the above-mentioned substrate, including an upper surface containing oxygen; the fluorene of the fonium is at the boundary with the above-mentioned substrate; The above dielectric change layer is processed in bulk. The above actinization is equivalent to infinite multilayer optical gradation light 4 at a wavelength of less than 2 °. The light source is a layer, and at the same wavelength, a single-layer dielectric is used as the bottom impedance. The reflectivity under the exposure source in the reflection lithography process is low, and in the subsequent anti-reflection layer At the time, the release of Erxin 4 with the above-mentioned optical gradient layer as the bottom released the basic ionic strength, which was much higher than that of the single layer described above. Page 10 0522-8457TWF (N); dwwang.Ptd 561552

V. Description of the invention (7) When the electric shell is used as the bottom anti-reflection layer, the ionic strength released is low. As mentioned above, the present invention achieves an optical gradient layer and its preparation method. The bottom anti-reflection layer of a single layer is treated with a gas plasma containing oxygen atoms. The anti-reflection effect of an infinite number of optical gradient layers is known. It is better than the traditional single-layer bottom anti-reflection layer, and the process complexity is lower than that of the bottom anti-reflection layer of double-layer or multi-layer structure, and the process time and cost can also be reduced. In addition, the present invention can also achieve an optical gradient layer and its producer j 'using a gas plasma containing oxygen atoms to process a single layer of the bottom anti-reflection layer, to obtain that the multi-layer optical gradient layer is also anti-reflection to the bottom. The surface of the layer is modified so that the optically graded layer is exposed to light during the photolithography process and then baked, thereby reducing the release of alkaline substances and avoiding the resolution of the chemically amplified photoresist. However, the present invention is a preferred embodiment. The disclosure is like 丨, but it is not intended to limit 2 r 'Wai: ί He who is familiar with this art, does not depart from the spirit of the invention ® ^ ^ ^ ^ -V ^ Noon changes and decorations, so the invention of The scope of protection shall be subject to the definition of the "scarves of money" patent.

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In order to make the above-mentioned objects, features, and advantages of the present invention more obvious and easy, the following detailed description is made with the accompanying drawings as follows: The drawings are briefly explained. Figure 1 shows a conventional single-layer anti-reflection of the bottom layer. Layer structure. FIG. 2 shows a conventional structure of a multi-layered bottom anti-reflection layer. Figures 3A and 3B show the steps and structure of forming an optical gradient layer in a preferred embodiment of the present invention. Fig. 4 shows the change in the oxygen atom content along the line AA 'in Fig. 3B in the preferred embodiment of the present invention. Fig. 5 shows the reflectance of the bottom anti-reflection layer before and after the electrical processing at the wavelength of human light emitted by different lithographic rays in a preferred embodiment of the present invention. FIG. 6 shows the comparison of the single-layer dielectric anti-reflection layer 31 as the bottom Deng Ying reflection layer and the optical The graded layer 34 serves as a bottom anti-reflection layer. Under different baking and temperature conditions, the intensity of the alkaline substance released by the bottom anti-reflection layer is low. 10 ~ substrate, 11 ~ single-layer bottom anti-reflection layer, 12 ~ resist, 20 ~ substrate, 21 ~ multilayer bottom anti-reflection layer, 21a ~ first layer of multilayer bottom anti-reflection layer, 21b ~ multilayer bottom anti-reflection layer The second layer of the reflective layer,

561552 Schematic description of 21c. ~ The third layer of the multilayer bottom antireflection layer, 21d, ~ The fourth layer of the multilayer bottom antireflection layer, 21e, ~ The fifth layer of the multilayer bottom antireflection layer, 30 ~ substrate, 31 ~ Single-layer dielectric anti-reflection layer, 33 ~ 02 plasma treatment, 34 ~ optical gradient layer. ΙΙΙϋ! 0522-8457TWF (N); dwwang.ρ td page 13

Claims (1)

561552 6. Scope of patent application i A method for forming an optical gradient layer, which is applicable to a substrate, includes the following steps: forming a dielectric on the substrate, including an upper surface and a lower surface, wherein the lower surface And the substrate is treated with an oxygen atom-containing gas plasma to form an optically-graded layer that acts as an anti-reflection layer and whose degree of oxidation gradually decreases downward from the upper surface. 2. The method of forming an optically graded layer as described in item 1 of the scope of the patent application, wherein the dielectric is selected from nitrides, carbides, oxynitrides, oxycarbides, or a combination thereof. 3. The method of forming an optically graded layer as described in item 2 of the scope of the patent application, 'wherein the nitrogen or carbon atoms in the dielectric molecule are replaced with oxygen atoms during the plasma treatment process, and the proportion of substitution It gradually decreases from the upper surface downward. 4. The method for forming an optically graded layer as described in item 1 of the scope of the patent application, wherein the gas plasma containing oxygen atoms is selected from a N2 plasma or a 02 plasma. 5. The method for forming an optically graded layer as described in item 1 or 4 of the scope of the patent application, wherein the power of the gas plasma containing oxygen atoms is 100 watts to 800 watts. 6. The method for forming an optically graded layer as described in item 1 or 4 of the scope of the patent application, wherein the dielectric anti-reflection layer is treated with the oxygen-containing gas plasma for a time of 2 to 30 minutes. 7 · The method of forming an optically graded layer as described in item 1 of the scope of patent application ', wherein the thickness of the optically graded layer is 15 nm to 100 nm. 0522-8457TWF (N); dwwang.ptd Page 14 561552 VI. Application for patent scope 8 · The method for forming an optically graded layer as described in item 1 of the scope of patent application 'wherein the oxygen atom-containing gas plasma treatment can reach a depth of i nm to 100 nm 0 9 · An optical graded layer formed on a substrate includes: forming a dielectric on the substrate, including an upper surface and a lower surface, wherein a lower surface is an interface with the substrate, and an oxygen-containing atom is formed on the substrate; An optically graded layer formed by processing the dielectric material as an anti-reflection layer with an oxidizing degree gradually lowered downward from the upper surface. 10. The optically graded layer according to item 9 in the scope of the patent application, wherein the material of the dielectric is selected from nitride, carbide, oxynitride, carbide, or a combination thereof. 11. The optical gradient layer according to item 10 in the scope of the patent application, wherein the material of the optical gradient layer is composed of oxygen atoms replacing nitrogen atoms or carbon atoms in the molecules of the dielectric material, and the substitution ratio is determined by the The upper surface gradually decreases downward. 12. The optical gradient layer according to item 9 or 丨 丨 in the scope of application for a patent, wherein the thickness of the optical gradient layer is i 5 nm to 100 nm. 13. The optically graded layer according to item 9 of the scope of the patent application, wherein the depth of the plasma treatment with the oxygen atom-containing gas plasma is 1 nm to 100 nm. 14. A method of forming an optically graded layer, suitable for use on a semiconductor substrate, comprising the following steps: forming a dielectric on the semiconductor substrate, including an upper surface and a lower surface, wherein the lower surface is related to the Semiconductor substrate junction, and the dielectric 0522-8457TWF (N); dwwang.ptd Page 15 561552 The substrate is selected from the group consisting of nitride, carbide, oxynitride, carbon oxide, or a combination thereof; and the dielectric is treated with an oxygen atom-containing gas plasma to form an anti-reflection layer. , And the degree of oxidation gradually decreases from the upper surface downward. 15. The method of forming an optically graded layer as described in item 14 of the scope of the patent application, wherein in the plasma treatment process, nitrogen atoms or carbon atoms in the dielectric molecule are replaced with oxygen atoms, and the substitution ratio is determined by the The upper surface gradually decreases downward. 16. The method for forming an optically graded layer as described in item 14 or 5 of the scope of the patent application, wherein the gas plasma containing oxygen atoms is selected from N20 plasma or 02 plasma. 17. The method for forming an optically graded layer as described in item 16 of the scope of patent application, wherein the power of the gas plasma containing oxygen atoms is 100 watts to 800 watts. 18 · The method for forming an optically graded layer as described in item 6 of the scope of the patent application, wherein the dielectric anti-reflection layer is treated with the oxygen atom-containing gas plasma for a time of 2 to 30 minutes. 19. The method for forming an optically graded layer as described in item 14 of the scope of patent application, wherein the thickness of the optically graded layer is 15 nm to 100 nm. 20. The method for forming an optically graded layer as described in item 14 of the scope of the patent application, wherein the oxygen plasma-containing gas plasma treatment can reach a depth of 1 nm to 100 nm 〇21 · —an optically graded layer formed on / On semiconductor substrates, including: 0522-8457TWF (N); dwwang.ptd Page 16 561552 6. The scope of the patent application A dielectric is formed on the semiconductor substrate, including an upper surface and a lower surface, where the lower surface is at the interface with the semiconductor substrate And the medium is selected from the group consisting of nitride, carbide, oxynitride, oxycarbide, or a combination of the foregoing; and an action formed by treating the dielectric with a gas plasma containing an oxygen atom. An anti-reflection layer, and an optically graded layer whose oxidation degree gradually decreases from the upper surface downward. 22. The optical gradient layer according to item 21 of the scope of application for a patent, wherein the material of the optical gradient layer is to replace oxygen or carbon atoms in the dielectric material with oxygen atoms, and the substitution ratio is from the upper surface to Down gradually decreases. 23. The optical gradient layer according to item 21 of the scope of application for a patent, wherein the thickness of the optical gradient layer is 15 nm to 100 nm. ^ 24. The optically graded layer according to item 21 of the scope of patent application, wherein the depth of the plasma treatment with the oxygen atom-containing gas plasma is 1 nm to 100 nm. 25 · —A method for forming an optical gradient layer, which is applicable to a metal substrate and includes the following steps: forming a dielectric on the metal substrate, including an upper surface and a lower surface, wherein the lower surface is connected with The metal substrate is bordered, and the dielectric is selected from the group consisting of nitride, carbide, oxynitride, carbon oxide, or a combination thereof; and the dielectric is treated with a gas plasma containing oxygen atoms An electric substance is formed to form an optically graded layer as an anti-reflection layer, and the degree of oxidation gradually decreases downward from the upper surface. 26. Forming an optical gradient layer as described in item 25 of the scope of patent application 561552 VI. Application for patent method In the process of plasma treatment, oxygen atoms are used to replace nitrogen or carbon atoms in the dielectric molecule, and the proportion of substitution is gradually reduced from the upper surface downward. 27. The method for forming an optically graded layer as described in item 25 or 26 of the scope of the patent application, wherein the gas plasma containing oxygen atoms is selected from a ratio plasma or a plasma plasma. 28. The method for forming an optically graded layer as described in item 27 of the scope of patent application, wherein the power of the oxygen atom-containing gas plasma is 100 watts to 800 watts. 29. The method for forming an optically graded layer as described in item 27 of the scope of patent application, wherein the dielectric anti-reflection layer is treated with the oxygen-containing gas plasma for a time of 2 to 30 minutes. 30. The method for forming an optically graded layer as described in item 25 of the scope of patent application, wherein the thickness of the optically graded layer is 15 nm to 100 nm. 31. The method for forming an optically graded layer as described in item 25 of the scope of the patent application, wherein the reachable depth of the oxygen plasma-containing gas plasma treatment is 1 nm to 100 nm 〇32 · —an optically graded layer And formed on a metal substrate, including: forming a dielectric material on the metal substrate including an upper surface and a lower surface, wherein the lower surface is at the boundary with the metal substrate, and the dielectric material Selected from the group consisting of nitrides, carbides, oxynitrides, oxycarbides, or a combination of the foregoing; and a process formed by treating the dielectric with a gas plasma containing oxygen atoms 0522-8457TWF (N); dwwang.p t d p.18 561552 VI. Application Outline " " An optically graded layer that is an anti-reflective layer and whose degree of oxidation gradually decreases from the top surface downward. ^ 33. The optical gradient layer according to item 32 of the scope of the patent application, wherein the material of the optical gradient layer is to replace gas atoms or carbon atoms in the dielectric material with oxygen atoms, and the replacement ratio is determined by the upper surface. Gradually decrease. 34. The optical gradient layer according to item 32 of the scope of application for a patent, wherein the thickness of the optical gradient layer is 15 nm to 100 nm. 35. The optically graded layer according to item 32 of the scope of patent application, wherein the depth of the plasma treatment with the oxygen atom-containing gas plasma is 1 nm to 100 nm. 0522-8457TWF (N); dwwang.ptd Page 19