TW523808B - Method for improving the resolution of optic lithography - Google Patents

Abstract

A method for improving the resolution of optic lithographic is disclosed. The method includes a step of forming an etched layer on the substrate, an inorganic photoresist layer is spun-on the etched layer, and an atomic layer on the inorganic photoresist layer. Then, a deep ultraviolet light is illuminated to the inorganic photoresist layer such that the acid molecular is formed from inorganic photoresist layer. Next, the atomic layer is catalyzed by acid molecular and converted to metallic oxide by active oxygen atom. After oxidation, the oxide pattern can be obtained and it is easy by etching process.

Description

523808 V. Description of the invention (1) 5-1 Field of the invention: The present invention relates to a method for improving the resolution of optical lithography, and more particularly to a method for treating a photoresist layer by ultraviolet light irradiation. 5-2 Background of the Invention: _ The lithography process is mostly used for the manufacture of semiconductor components, such as integrated circuit wafers and electromagnetic drives, such as magnetic disk drives (d i s c d r i v e r) and magnetic tape drives (t a p e d r i v e r). The lithography process step includes depositing a photoresist material on a device by spin coating (s p i η-c oa t i n g), which can be a silicon wafer. Next, for the emitted light, such as ultraviolet light, X-ray, or ion or electron beam (ion 0 r e 1 e c t rοn b e am). The final step includes a developer solution, such as tetramethylammonium hydroxide (TMAH). Using it solution, it can be negative photo resist or positive light that emits photons. Resistance (positive photo resist) was removed. i

Page 5 523808 V. Description of the invention (2) The transfer of light from the case map is based on the meeting of the mass-blocking material, which is necessary for the inversion of the system. Moving the question to the bad case will cause the broken image to be transferred to the layer and the light image tool and DUV) to expose the case wavelength to improve the resolution of the underlying material. In addition, in the area of the photoresist pattern, these steps of micron light so that the transfer of the resist pattern is destroyed are even more ultraviolet and deep ultraviolet wavelengths used to generate a photoresist pattern by minimizing diffraction (resolution, but light The uncontrollable generated on the resist layer instead increases the quality of the underlying reflective material in the pattern of the underlying reflective material. The quality of the underlying reflective material will be significantly reduced. A resistive pattern will also be generated near the reflective area generated by the underlying material on the semiconductor substrate. The last micron geometric figure integrated electricity included when the optical lithography process was used in the deep ultraviolet 5 case. Although the short-term diffracti ο η constraint condition can easily affect the pattern, the It is because when the quality of this optical metal is changed for the first time, it is low in the irradiated area. The degree of stepped shape usually increases and the photoresistance in the region is destroyed. Therefore, the formation of is difficult to control. It is very difficult to make the circuit. In the traditional wafer pattern transfer process, the photosensitive material using organic polymers is used. The mask pattern is transferred to the conductive body of the wafer after the etching step. However, the photosensitive material of the organic polymer cannot be controlled. This is due to the short-wavelength radiation, such as deep ultraviolet light, when the organic photoresist layer is illuminated. The photoresist layer will cause a photochemical reaction (ph 〇 〇chemica 1 react i on) due to irradiation, which will cause the chemical bond to break, and this organic light can no longer be used.

Page 6 523808 V. Description of the invention (3) Resistive layer, which will increase the use cost of the photoresistive layer. Another disadvantage is to improve the resolution of the optical lithography process and reduce the wavelength during irradiation. When the irradiation wavelength is low, the characteristics of the organic polymer photoresist will be reduced and out-gassing will occur. The lens used for exposure will also be contaminated due to the photoresist layer being damaged. Will decrease. 5-3 Invention Purpose and Overview:

The main purpose of the present invention is to form an inorganic photoresist layer on a wafer to avoid the problem of chemical bond rupture caused by the photoresist layer due to irradiation. Another object of the present invention is to improve the problem of outgassing in the lithography process. Another object of the present invention is to improve the resolution of the optical lithography process. A secondary object of the present invention is to reduce the cost of replacing the photoresist layer in the integrated circuit manufacturing process. 0 According to the above-mentioned purpose, the present invention provides an embodiment in which a surname engraved layer, an inorganic photoresist layer, and an atomic layer are sequentially formed on a substrate. Then, the advantage of using this inorganic photoresist layer is that

Page 7 523808 V. Description of the invention After (4), the chemical bonding of the inorganic photoresist layer will not be interrupted by the irradiation of ultraviolet light, and no outgassing will occur. Then, when the ultraviolet light is irradiated to the inorganic photoresist layer, the inorganic photoresist layer thus generates an acid molecule that can be used as a catalyst, and then the acid layer is used to catalyze the atomic layer, and then react with the active oxygen atom to oxidize Forms oxides. The formation of this oxide makes subsequent etching processes easy. 5-4 Detailed Description of the Invention: Some embodiments of the present invention will be described in detail as follows. However, in addition to the detailed description, the present invention can also be widely implemented in other embodiments, and the scope of the present invention is not limited, which is subject to the scope of subsequent patents. The tools for optical lithography include at least an ultraviolet (UV) light source, a mask, an optical system, and a wafer with a photosensitive layer. The photosensitive layer can also be called a photoresist layer. ). This is because the photosensitive layer can be used as an anti-resistance chemical in subsequent processes. For optical lithography technology, most of them are arc lamps and laser sources that use ultraviolet light sources and are under high voltage. The spectral range of the emitted light can be divided into three parts: deep UV between 100 nm and 300 nm, and between 300 nm and 360 nm.

Page 8 523808 V. Description of the invention (5) is medium-ultraviolet light (mid-UV) and near-UV light is in the range of 360 nm to 450 nm. In the preferred embodiment of the present invention, a substrate is provided and a layer on the substrate can be used as a money engraved layer (e ^ ched 1 ayer), an inorganic photoresist layer is on the etching layer and an atom The layer is on the inorganic photoresist layer. Next, an ultraviolet light with a wavelength of about 15 7 nanometers is irradiated through the mask to generate acid molecules on the inorganic photoresist layer. At the same time, oxygen also forms active oxygen atoms due to the irradiation of ultraviolet light. Among them, the acid molecule is used as a catalyst to catalyze the atomic layer, and the active oxygen atom is used to oxidize the atomic layer that has been catalyzed to form an oxide. Next, an etching step is performed on the atomic layer to remove the oxide by etching. Then, using the atomic layer as a photomask, the inorganic photoresist layer and the engraved layer are sequentially etched. The advantage of the present invention is that the chemical bonding of the inorganic photoresist layer will not be damaged by the irradiation of ultraviolet light, which can reduce the cost in the whole process. Another advantage is that an oxide pattern can be obtained so that the etching step can be easily performed. Referring to the first figure, as the etched etching layer 丨 2 is deposited on the substrate 10 ′, wherein an oxide or polycrystalline silicon can be used as the material of the etching layer 12. An inorganic photoresist layer is formed on the etching layer 12 by spin coating. The inorganic photoresist layer 14 is a photo acid generator layer (PAG layer, photo acid generator layer). The photo-acid-forming layer 14 is composed of a photo-acid-generating compound, and the photo-acid-generating compound is in an exposed area 523808. 5. Description of the invention (6), especially in the case of ultraviolet light irradiation Acid molecules are generated, and then an atomic layer 16 is deposited on the photoacid-forming layer 14 by a general chemical vapor deposition (CVD) method. The material of the atomic layer 16 may be metal inscriptions or aluminum alloys. For deep lithography, the most commonly used laser light source is the e X c i m e r laser light source. The word e X c i m e r is obtained by a combination of excitation (e x c i t e d) and a dimer (di m m r). The so-called dimer is a kind of two completely similar atoms, such as krypton (K r 2). The e X cimer sub-system is used to describe excited compounds, such as rare gas halides, such as' KrF (krF, krypton-fluoride), XeC (xenon-chloride), and ArF (ArF) , Argon -f 1 uo ride). In the preferred embodiment of the present invention, the M light source for deep ultraviolet light is a mouse (F2, fluoride). The wavelength generated by the excimer laser light source is about 1 5 7 nanometers (nm, nanometer). The resolution when using fluorine as the light source ranges from 100 nanometers to 70 nanometers, which is better than the resolution of argon fluoride used in the past. The resolution range of argon is between 130 nanometers and 100 nanometers. Then referring to the second and third figures, a deep ultraviolet light having a wavelength of 15 7 nanometers 2 is irradiated through a photomask 20 to An inorganic photoresist layer 14 on the wafer. Then, 'acid molecules are formed on the irradiated area 26 and below the atomic layer 16 due to the irradiation of ultraviolet light 24, and the acid molecules are

Page 10 523808 V. Description of the invention (7) The inorganic photoresist layer 16 is generated by irradiation. This acid is also called Lewis acid, which is used as a catalyst for catalyzing the atomic layer 16. When the ultraviolet light 24 is irradiated to the inorganic photoresist layer 14, the oxygen in the reaction chamber is also decomposed to form active oxygen atoms due to the ultraviolet light. This active oxygen atom is used to oxidize the atomic layer 28 (shown in the fourth figure) that has been catalyzed by the acid molecule. Referring to the fourth and fifth figures, an atomic layer 28 that has been catalyzed by an acid molecule is formed over the exposed area 26, and performs an oxidation reaction with an active oxygen atom. After oxidation, an oxide 30 (metallic oxide) is formed on the atomic layer 16. The chemical formula of this oxide can be written as B x0 y, where B is a metal (that is, an atom of an atomic layer), and 0 is an oxygen atom. At the same time, patterns of oxides can also be obtained. Next, an engraving step is performed on the atomic layer 16 to remove the oxide 30 by using a different etching ratio between the oxide 3 0 and the atomic layer 16. Then, the non-etched atomic layer 16 is used as an etching mask, and then the inorganic photoresist layer 14 and the remaining layer 12 are sequentially etched.

Page 11 523808 V. Description of the invention (8) The acid molecules produced by the inorganic photoresist layer through ultraviolet light irradiation are used as catalysts to catalyze the atomic layer and then oxidize the atomic layer with active oxygen atoms. After the oxidation, an oxidized pattern can be obtained on the wafer and the etching step can be easily performed. The above are merely preferred embodiments of the present invention, and are not intended to limit the scope of patent application for the present invention; all other equivalent changes or modifications made without departing from the spirit disclosed by the present invention shall be included in the following Within the scope of patent application.

Page 523808 Brief description of the diagram The first diagram is a schematic diagram of the structure of an undercut layer, an inorganic photoresist layer, and an atomic layer sequentially formed on a substrate according to the technology disclosed in the present invention. The second diagram is based on The technology disclosed in the present invention covers a structure of a photomask on the structure of the first diagram; the third diagram is a structure diagram of an inorganic photoresist layer irradiated with ultraviolet light through the mask according to the technology disclosed in the present invention; The fourth figure is a schematic diagram of the structure of the atomic layer in the region illuminated by the acid molecules provided by the inorganic photoresist layer according to the technology disclosed in the present invention; and the fifth figure is based on the disclosure of the present invention. Technology, the structure of the fourth figure is oxidized to form an oxide structure. Representative symbols of main parts: 1 0 substrate 1 2 engraved layer 1 4 inorganic photoresist layer 1 6 atomic layer 20 photomask 2 4 ultraviolet light

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Claims (1)

523808 6. Application scope 1. A method for processing a photoresist layer, the method at least comprises: providing an inorganic photoresist layer on a substrate and an atomic layer on the inorganic photoresist layer, wherein the inorganic photoresist layer Is used to provide acid molecules; irradiate an ultraviolet light to the inorganic photoresist layer so that the inorganic photoresist layer forms a plurality of acid molecules; and oxidize the atomic layer on the irradiated area with active oxygen atoms to convert into an oxide On this atomic layer. 2. The method according to item 1 of the patent application range, wherein the substrate includes at least one remaining etched layer. 3. The method according to item 2 of the patent application, wherein the material of the etching layer includes an oxide. -4. The method according to item 2 of the patent application, wherein the material of the etching layer includes a polycrystalline stone. 5. The method according to item 1 of the patent application range, wherein the inorganic photoresist layer is a photo acid generator (PAG layer, photo acid generator) 6. The method according to item 1 of the patent application scope, further comprising forming a plurality of active oxygen atoms after the irradiation step. 523808 6. Scope of patent application 7 · The method of the first scope of patent application, wherein the above-mentioned ultraviolet light contains at least one deep ultraviolet light. 8. The method according to item 7 of the patent application, wherein the wavelength of the above-mentioned deep ultraviolet light is about 157 nanometers (nm, nanometer). 9. The method according to item 1 of the patent application, wherein the material of the above atomic layer includes Shao. 10. The method according to item 9 of the scope of patent application, wherein the material of the atomic layer _ includes a Shao alloy. 11. A method for improving the resolution of optical lithography, the method at least comprises: providing a substrate having an etched layer, an inorganic photoresist layer on the #etched layer, and an atomic layer on the inorganic light On the resist layer; irradiating the inorganic photoresist layer with deep ultraviolet light so that a plurality of acid molecules are formed on the irradiation area, and simultaneously decomposing oxygen to form a plurality of active oxygen atoms; using the plurality of acid molecules to catalyze the atom layer; And using the plurality of active oxygen atoms to oxidize the atomic layer located on the irradiation area to convert it into an oxide on the atomic layer. 12. The method according to item 11 of the scope of patent application, wherein the material of the etching layer comprises an oxide. Page 16 523808 6. Scope of patent application 1 3. The method according to item 11 of the scope of patent application, wherein the material of the above-mentioned etching layer includes a polycrystalline stone. 14. The method according to item 11 of the scope of patent application, wherein the inorganic photoresist layer is a photoacid-forming layer. 15. The method according to item 11 of the patent application range, wherein the material of the atomic layer comprises aluminum. 16. The method according to item 15 of the scope of patent application, wherein the material of the atomic layer includes an alloy. 17. The method according to item 11 of the scope of patent application, wherein the wavelength of the above-mentioned tritium ultraviolet light is about 157 nanometers (nm, nanometer). 1 8. A method for improving the resolution of an inorganic photoresist layer, the method at least comprising: providing a substrate having an oxide layer; spin coating an inorganic photoresist layer on the oxide layer; depositing an aluminum atom layer on the layer The inorganic photoresist layer is irradiated with deep ultraviolet light to the inorganic photoresist layer so that the inorganic photoresist layer generates a plurality of acid molecules on the irradiated area, and simultaneously decomposes oxygen to form a plurality of active oxygen atoms; using the majority Acid molecules catalyze the aluminum atomic layer; and Page 17 523808 Six of the top 19 materials 20 materials 2 1. The method according to item 18 of the patent application has a wavelength of about 15 7 nm. The scope of the patent application uses the plurality of active oxygen atoms to oxidize the irradiated area. The method of converting the atomic layer into an oxide at the atomic layer such as the method in item 18 of the patent application range, wherein the above oxidation The material of the layer contains polycrystalline silicon. For example, the method according to item 18 of the scope of patent application, wherein the aluminum atomic layer includes an alloy. Where the above-mentioned deep ultraviolet light wave