TWI231528B - Method of preventing photoresist residues - Google Patents

Abstract

A method to prevent photoresist residues formed in a contact or via hole is provided. The method includes using a halogen-containing plasma treatment before the contact or via hole is filled with a photoresist. Due to the halogen-containing plasma treatment, amine components on the sidewalls of a via or contact hole or trench opening can be efficiently removed. Accordingly, photoresist residues or via poison can be avoided.

Description

1231528 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a method for manufacturing a semiconductor integrated circuit, and more particularly to a method for forming a dual-mosaic structure in a semiconductor integrated circuit. [Prior Art] Many elements are connected to each other using metal wires in a semiconductor wafer. Generally, a metal window is connected to each semiconductor circuit element using a contact window, and a metal window is used to connect the metal wires. The connection points of metal wires and vias / contacts are usually made using different lithography, etching, and film deposition processes. As the size of semiconductor elements continues to shrink, semiconductor wafers are getting smaller and smaller, and the density of elements is getting higher and higher, so misalignment between different pattern layers (M i sa 1 i gnment) often occurs. In the conventional technology, some methods are used in the semiconductor wafer process to improve the resolution of Gao Zhengying's processes, such as deep ultraviolet (j) eep U 11 ra-vi ο 1 et, DUV) and extreme ultra-violet, EUV) light engraving technology to improve the resolution of semiconductor processes, it uses a light source with a wavelength of 193nm or 157nm, or even shorter wavelengths. Due to the resistance value of the metal wire and the parasitic capacitance between the wires, the problem of the resistance-capacitance (Rc) delay of the multilayer interconnection in another semiconductor circuit is caused. These are the main factors affecting the operation speed of the semiconductor circuit. Other methods use various materials to solve the problem of RC delay. For example, in the semiconductor industry, low dielectric constant materials are often used because of their lower dielectric constant. In addition, copper metals with low resistance values can also be used instead of aluminum copper (A 1 -Cu) metal as a conductive material. Due to the low dielectric constant material and low

1231528 V. Description of the invention (2) Copper metal with resistance value, so it can effectively reduce the RC delay effect of multilayer interconnects in the semiconductor circuit structure. However, it is not easy to etch copper metal by the traditional etching process. Therefore, a dual damascene process is used to manufacture copper interconnects instead of the traditional patterning process. Generally speaking, the dual damascene process is divided into a damascene process that first forms a trench and a damascene process that first forms a via hole. In the step of the damascene process that first forms a trench, the metal dielectric is interconnected. A trench opening is formed on the (Inter-metal Layer 'IMD) layer, and then a patterned photoresist layer is formed on the I MD layer having the trench opening to form a via hole structure. Generally, a patterned photoresist layer forming a via structure is located within the trench opening. Then, an etching process is performed to form a via hole in the IMD layer. Finally, a conductive material such as aluminum-copper or copper metal is filled in the via hole and the trench opening to form the via layer and the trench wire, respectively. In the step of forming a via hole first, a via structure is etched in the IMD layer with an etch stop layer, and then a patterned photoresist layer is deposited on the wafer with the via structure to form a trench structure. . An etch process is then used to form a trench structure, and an etch stop layer is used to remove a portion of the IMD layer. In addition, the feature of the damascene process of forming a via hole first is to form a photoresist polymer (Polymer) to fill in the via hole to protect the metal conductive layer under the via hole and avoid the trench etching process Damage 'Finally, a metal is filled in the via hole structure and the trench opening', for example, a copper or copper, silver, gold, alloy and other metals to form a via and a trench wire, respectively. In a damascene process where a dielectric hole or trench is first formed, a dielectric layer is used as

Page 7 1231528 V. Description of the invention (3) It is an anti-reflection coating (ARC), and it is terminated by an etching stop layer or chemical mechanical polishing (CMP) in the sacrificial damascene process. Floor. The reason for using the anti-reflection layer (ARC) is to avoid or eliminate the interference or diffraction effects caused by the reflected light during the lithography process. In addition, in order to planarize the surface of a multilayer structure of a semiconductor circuit, a CMP process or a surface return process is required. Generally, a CMP process is used when a strongly bonded dielectric layer responds to etchback. Ji Huan According to the requirements of the lithography process and the planarization process, silicon oxynitride is used as the reflective layer '. However, the anti-reflection layer also has several problems in the semiconductor circuit structure. 9! Wang Sheng him

The problem of the lithography process is the nitrogen-containing medium and D. Therefore, the mutual reciprocity between the nitrogen-containing medium layer and the photoresist layer is based on the photoacid, which leads to a part of the photoresistance in the development process; First: Residual = edge = structural sidewalls appear in the via hole or contact hole. When ^ mm On, the phenomenon is called the drawer / 4 vertical contact obstruction (Pollslon), and it is used in the conventional technology—the company ’s Θ seed | layer / connection to solve these processes. The question ❶ II., '. Structure and method A method for reducing the interlayer obstruction of the dual damascene structure, as described in Patent No. 319, No. 6, Figure: First, a metal layer i 1 0 and No. 1 are formed on a substrate. Companion technology = Sequentially formed a constant two ^ 15 on the first protective layer 115, and then ... stop layer 125, the second low dielectric constant dielectric and the first meaning 1231528 V. Description of the invention (4) 1 3 5 . Then, a photolithography process is used to form a via / contact hole in the multilayer structure. After the photoresist is removed, a UV radiation step is used to remove the residual photoresist on the via / contact hole. FIG. 2 shows a method for reducing the resistance of the interlayer / contact hole and removing the photoresist. For example, US Patent Application No. 2001/003674 0, a metal layer 210 is first formed on a substrate 200, and then a substrate 20 is formed. An inter-layer dielectric (IL) 2 2 0 and a photoresist layer 2 3 0 are sequentially formed on 0, and then a contact hole or a via hole 24 is formed in the ILD layer 220 and the photoresist layer 230. 〇, and then use CF and HA plasma 250 to remove the photoresist residue 26 and the photoresist layer 230, wherein the photoresist residue 260 is formed in the interlayer / contact hole etching process. It is therefore necessary to avoid the formation of photoresist residues in the openings, which are vias, contact holes or trenches. [Summary of the Invention] ^ 1 month long, a manufacturing method for avoiding the formation of photoresist residues in the openings. Before the photoresist is filled in the openings, firstly use the electric element containing The system is used to form a trench pattern. The photoresist may be, for example, DUV light, or an electron beam photoresist. Nitrogen-containing materials or sources of low-resistance photoresistance, due to amines, 'photoresistance (especially, >', ...) is completely transferred to an acidic substance after the exposure step, and the side of the hole is blocked The residue will adhere to the edge of the patterned feature shape or open " V. Before using the photoresist to form a trench pattern on the substrate, perform

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1231528 V. Description of the invention (5) Electrocracking treatment step 'to reduce the nitrogen-containing component or amine component on the surface of the cover layer and the side wall of the opening. Because the electric treatment can react with amine to form an acidic environment, the photoresist used to form the trench pattern will not react with the test material of the interlayer material by eliminating or reducing the photoreceptive components, effectively avoiding photoresist. Residues or residues of harmful vias. [Embodiment] Figures 3A-3D are cross-sectional views showing a process of forming a interlayer dual damascene structure in a semiconductor circuit according to the present invention. FIG. 3A is a cross-sectional view showing a multilayer material structure formed on a substrate 300 according to the present invention. First, a substrate 300 having a wire 310 is provided. The substrate 300 is a semiconductor with various components. The substrate 300 may be, for example, a silicon substrate of a semiconductor, a silicon germanium substrate, an insulating silicon substrate (SOI), or III— Group V composite substrate. The conductive wire 3 1 0 is composed of a conductive material, such as copper-metal or copper metal. In addition, the conductive wire 3 1 0 can be formed by a lithographic etching method or a chemical mechanical polishing method. Next, a multi-layer material structure is formed on the substrate 300, that is, a protective layer 315, a first dielectric layer 320, an epitaxial termination layer 330, a second dielectric layer 3400, and a protective layer 315 are sequentially formed on the substrate 300. Cover layer 350. The protective layer 3 15 is used to protect the components on the substrate 300 to isolate impurities generated by the first dielectric layer 3 2 0. The protective layer 315 may be, for example, a silicon nitride layer, a oxynitride layer, a carbide stone layer, or any material having the same function as the protective layer 315. In an embodiment ’using a nitrided layer as a protective layer 3 1 $, thickness

Page 10, 1231528 V. Description of the invention (6) === Angstrom, and using atmospheric pressure chemical vapor deposition method (_ to form it. When the interstitial hole / connection: hole description 'Wang Shi, etching The termination layer 3 3 0 is used to prevent the bottom layer from being damaged to form a dual damascene structure. Generally, the f ′ etching process has a higher residual rate for the second dielectric layer 34.02 and the termination layer 3 3 0. When When a nitrided layer is used as the etch stop layer 330, the thickness of the silicon nitride layer is between 0 and 1,000 Angstroms, and the atmospheric pressure chemical vapor deposition method (ApcvD) or low-pressure chemical gas is used. Formed by phase deposition (LPCVD) or plasma-assisted chemical vapor deposition (pEcvD). The cover layer 3 50 is used as the anti-reflection layer (arc) in the subsequent lithography process. In addition, the cover layer 3 50 can also be used as an etching The termination layer, the protective layer, or a combination thereof. The cover layer 350 may be, for example, a silicon nitride layer or a silicon oxynitride layer ^ is any material having the same function as the cover layer 350. In one embodiment, The silicon nitride layer is used as the cover layer 3 50, and the thickness is between 500 and 700 angstroms. Method (APCVD) or low pressure chemical vapor deposition (LPCVD) or plasma-assisted chemical vapor deposition (PECV). The first dielectric layer 320 and the second dielectric layer 340 may be the same or different. The material of the dielectric constant, the dielectric constant is less than 4.0, for example, SiLK (Poly-arylene Ether), FLARE (Fluorinated Poly-arylene Ether), or HSQ (Hydrogen Silsesquioxane). In one embodiment, the first dielectric layer 320 The thickness of the second dielectric layer 340 is between 2000 and 6000 angstroms, and can be formed by a spin coating method or a chemical vapor deposition method. In another embodiment, the first dielectric layer

Page 11 1231528 V. Description of the invention (7) _ The layer 32 0 and the second dielectric layer 3 40 may be low dielectric lightning a greater than 3.0. Number material, its dielectric constant. Those familiar with this technology should understand the above-mentioned multi-drawer process technology and the new ^ = quality structure used to form all dielectric layers on the integrated electrical substrate 300. Only 4 and it doesn't need to be in the wood material, the customer ® + like the ground 'in addition to the material shell calendar shown in Figure 3' evening layer material structure can also include the factory's 3B figure showing the first 3A picture of multiple layers ;; material layers. Structure scraping surface. A knot that forms an opening in the material structure of the mouth Yixi shield forms a p on the cover layer 3 50 and 厣 f to 厫 —etching process, using the traditional lithography = i 2 i ΐ to make an opening. Then, a patterned photoresist layer is used as a mask to remove a cover layer 350, which is known by Γ op, and a second interposer G hole Mo 2: stop layer 330, dielectric In the process of forming the layer 320 and the protective layer 315 in the shape of the interlayer double-mosaic structure, holes are formed. In addition, continuous multi-layer etching of -M is performed using continuous anisotropic etching. This etching process can be performed in a single reaction chamber or in different reaction chambers. FIG. 3C shows a cross-sectional view of the structure of the plasma treatment 380 after the polymer plug 37 is formed in the via 36 36. Next, a process for forming the plug 37 and a plasma treatment process will be described. After the openings 360 are formed, a filling material (not shown) is filled in the openings 360 and the surface thereof is flattened. The filling material may be, for example, a polymer material such as a resin. Then, an etch-back step is performed to remove a part of the filling layer and form a polymer filler 370 in the opening 36 of FIG. 3C. The purpose of the polymer filler 370 is to protect the conductor 3 丨 〇, Free from damage in subsequent etching processes.

Page 121231528 V. Description of the invention (8) However, it is not necessary to form a polymer filler 370 'in the opening 360, but using the polymer filler 3 7 0 will more effectively protect the substrate 3 0 0 from subsequent etching Process damage. Next, a plasma treatment process 380 is performed. The plasma treatment process 380 uses a halogen-containing plasma. The halogen contains fluorine, chlorine, molybdenum, or indium. If a plasma containing chlorine is used to process the substrate in the manufacturing process, a gas containing chlorine can be used as a gas source. The gas source is C 1 2, HC, C XC 1 y, C XH yC 1 Wei is one of the combinations, To produce a gas-containing plasma. In one embodiment, the plasma treatment 380 includes a nitrogen component and an inert gas. The nitrogen component may be generated from a nitrogen-containing gas, such as N 20 is N 20, and the October gas may be helium, gas, argon, or krypton. In a preferred embodiment, gas (eh) is used as the plasma source, and the flow rate is between 5 and 400 sccm, and the flow rate is between 10 and 400 SCcm. In addition, N2 / 0 can be used in the described embodiments. In another embodiment, the plasma treatment 380 may use a dual power supply system, a charger, by applying an electrode power source between 2000 and 2000 wa 11 s, and a voltage between / 0 and 400 watts. Lower electrode power. Those skilled in the art should know that the above-mentioned embodiment is fine-tuned to achieve the purpose of removing the content or amine located in the opening 360. The human page Π forms a structural cross-section of the patterned photoresist layer 390. In the process of forming the :: embedded structure, the purpose of the photoresist layer 390 is to shape the layer 39 °. For example, it can be a DUV photoresist layer, or any photoresist, as described above, a nitrogen-containing material or a source. Due to the basicity of the amine, it is completely converted into two cases after the exposure step, which is generated by the benzylamine, and is attached to the edge of the patterned feature shape or the side of the opening.

Page 13 1231528 V. Description of the invention (9) Before the resist layer 39 0 forms a trench pattern on the substrate, plasma treatment 380 steps are performed to remove the inclusions on the surface of the cover layer 3 50 and the side wall of the opening 3 6 0. Nitrogen or amine. Because the plasma treatment 380 can react with amines to neutralize the bases and form a neutral or acidic environment, the photoresist layer 390 used to form the trench pattern will not react with the multilayer material structure. Figures 4A-4C are cross-sectional views illustrating a process for forming a trench dual damascene structure in a semiconductor circuit according to the present invention. The numbers of the same components as 4A-4C and 3A-3_ increase by 1 0 0. These components include a substrate 400, a wire 4o, a protective layer 415, a first dielectric layer 420, an etch stop layer 43o, a second dielectric layer 440, a cover layer 450, and a plasma treatment 48o. The details of the components will not be repeated. FIG. 4A shows a cross-sectional view similar to FIG. 3A according to the present invention. A protective layer 415, a first dielectric layer 420, an etch stop layer 430, a second dielectric layer 440, and a cover layer 450 are sequentially formed on the substrate 400. FIG. 4B shows a cross-sectional view of the structure of the openings 460 in a multilayer material structure and 480 according to the present invention. : ί: 4 A photoresist layer (not shown) is formed on the top, which is formed by using a traditional lithography resist layer to etch a ί layer. Then, a patterned photo-electric layer 42 is used to remove a part of the cover layer 450 and the second channel double-mounting :: into: hole 46 °. In the embodiment of the present invention, the trenches unequal two holes 460 are formed as a trench opening. In addition, part of the multi-layer material structure is continuously removed by etching, which is harmful in the etching process. As described above, the dielectric layer 420 ′ avoids etch damage 所述 As described in Section 3B, the manufacturing process of this multilayer material structure is etched.

1231528 V. Description of the Invention (ίο) Performed in the same reaction chamber. In addition, it is not necessary to add all material layers to the structure. Similarly, in addition to the material layers shown in FIG. 4A, more material layers can be included. Plasma treatment process 480 is followed. Plasma treatment process 480 uses a halogen-containing plasma. The halogen contains fluorine, chlorine, bromine, or indium. If a plasma containing chlorine is used to process the substrate in the process, a chlorine-containing gas can be used as a gas source. The gas source is C 12, HC 1, C XC 1 y, C XH yC 1 Wei is one of the combination, To produce a chlorine-containing plasma. In one embodiment, the plasma treatment 480 includes a nitrogen component and an inert gas. The nitrogen component may be generated from a nitrogen-containing gas, such as N 20 and N 20. The inert gas may be helium, neon, argon, or xenon. It is worth noting that the plasma treatment process 480 does not require the use of nitrogen and inert gases. In a preferred embodiment, chlorine is used as the plasma source, and its flow rate is between 5 and 40 sccm, and argon is used. The rate is between 10 and 4 0 sccm. In another embodiment, the electric beam treatment 480 can use a dual power supply system by applying an electrode power supply between 2000 and 2000 wa 11 s and an electrode power supply between 0 and 400 watts. . Those skilled in the art should know how to fine-tune the above embodiments to achieve the purpose of removing nitrogen-containing components or amines in the openings 460. Figure 4C shows a view of the social structure of the patterned photoresist layer 49〇 according to the present invention. In the process of forming the trench dual damascene structure, the photoresist layer 3 °° purpose is used to form the interlayer pattern. Light The resist layer 490 may be, for example, a Duv photoresist layer, or a photoresist. As described above, a nitrogen-containing material or a low dielectric constant material is the source of the amine ^. Due to the experimental characteristics of the amine, the &太太 图 奁 Serve's wins and benefits 々 / Therefore 'resistance of photoresist is on the edge of the patterned feature or the side of the opening

Page 15 1231528 V. Description of the invention (11) Resist layer 49 0 Before forming a trench pattern on the substrate, perform a plasma treatment 480 step to reduce the nitrogen-containing component or amine located on the surface of the cover 450 and the side wall of the opening 460. ingredient. Because the plasma treatment 480 can react with amine to form a photoacid, by eliminating or reducing the amine component, the photoresist layer 49 0 used to form the trench pattern will not react with the multilayer material structure of FIG. 4C. Before filling the openings (such as vias / contact holes or trenches with photoresist), apply a plasma treatment containing halogen to avoid photoresist residues in the openings. [Although the present invention has been disclosed as above with a preferred embodiment, it is not used when "π μ defines the present invention. Any person skilled in this art can make various changes and modifications without departing from the spirit and scope of the present invention. Retouching, so the second addiction of the present invention. 丨 Mu Lin's scope shall be determined by the scope of the attached patent application.

Page 16 1231528 Brief description of the drawings [Simplified description of the drawings] In order to make the above and other objects, features, and advantages of the present invention more comprehensible, the following describes the preferred embodiments with the accompanying drawings to make The detailed description is as follows: FIG. 1 is a cross-sectional view showing a structure of a conventional technique. FIG. 2 is a cross-sectional view showing another structure of the conventional technology. Figures 3A-3D are cross-sectional views showing a process of forming a interlayer dual damascene structure in a semiconductor circuit according to the present invention.

Figures 4A-4C are cross-sectional views illustrating a process for forming a trench dual damascene structure in a semiconductor circuit according to the present invention. [Simple description of element representative symbols] 110 metal layer 115 first protective layer 1 2 0 first low dielectric constant dielectric layer 1 2 5 etch stop layer 130 second low dielectric constant dielectric layer 135 second protective layer 20 0 Substrate 210 Metal layer 220 Inner dielectric layer 230 Photoresist layer 240 Interlayer hole 250 Plasma 2 6 0 Photoresist residue 3 0 0

3 1 0 wire 3 1 5 protective layer 320 first dielectric layer 330 etch stop layer 340 second dielectric layer 3 5 0 cover layer 3 6 0 openings 3 7 0 polymer filler 380 plasma treatment 390 photoresist layer

Page 17 1231528 Brief description of the diagram 4 0 0 substrate 41 0 wire 415 protective layer 420 first dielectric layer 43 0 etch stop layer 440 second dielectric layer 4 5 0 cover layer 4 6 0 opening 480 plasma treatment 490 photoresist layer

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Claims (1)

1231528 6. Scope of patent application 1. A manufacturing method for avoiding the formation of residual photoresist in the openings. Before the step of filling the photoresist in the openings, at least the step of using a halogen-containing plasma for processing is included. 2. The process method as described in item 1 of the scope of patent application, wherein the opening is a via hole or a contact hole. 3. The process method as described in item 2 of the patent application scope, wherein the photoresist is used to form a trench pattern. 4. The process method described in item 1 of the scope of patent application, wherein the photoresist is a deep ultraviolet (DUV) photoresist. 5. The manufacturing method according to item 1 of the scope of patent application, wherein a sidewall of the opening has a nitrogen component. 6. The process method as described in item 5 of the scope of patent application, wherein the nitrogen component includes at least an amine component. 7. The process method as described in item 6 of the scope of the patent application, wherein the step of treating with a halogen-containing plasma is to reduce the amine component on the side wall of the opening. 8. The process method described in item 1 of the scope of patent application, wherein the use of halogen-containing Page 19 1231528 VI. Scope of patent application The process of plasma processing by element includes at least the use of chlorine reaction gas. 9. The process method as described in item 8 of the scope of the patent application, wherein the chlorine reaction gas system is selected from one of a combination of Cl2, H (M, CxCly, CxHyCl ^). The process method, wherein the chlorine reaction gas system is C 12. 11. The process method according to claim 10 in the patent application scope, wherein the chlorine reaction gas further comprises an inert gas. 1 2. As in the patent application scope item 11 The process method, wherein the inert gas is argon. 1 3. The process method according to item 12 of the scope of patent application, wherein the C 1 flow rate is between 5 and 4 0 0 sccm, and The flow rate of argon is between 10 and 400 sccm. 1 4. The process method as described in item 13 of the scope of patent application, wherein the chlorine reaction gas further comprises a nitrogen component. 1 5. According to the scope of patent application The method according to item 14, wherein the nitrogen component uses N as a gas source. Page 20 1231528 6. Scope of patent application 1 6. — A process method to avoid the formation of residual photoresist in the via / contact hole, at least before the step of filling the photoresist in the via / contact hole, at least Contains the step of processing using a gas-containing plasma. 17 · The process method as described in item 16 of the patent application scope, wherein the photoresist is used to form a trench pattern. 1 8. The process method as described in item 17 of the scope of patent application, wherein the photoresist is a deep ultraviolet (DUV) photoresist. 19. The process method as described in item 16 of the scope of patent application, wherein the sidewall of the via / contact hole has a nitrogen component. 20. The process method as described in item 19 of the scope of patent application, wherein the nitrogen component includes at least an amine component. 2 1. The process method as described in item 20 of the scope of the patent application, wherein the step of using the chlorine-containing plasma for processing is to reduce the amine component on the side wall of the opening. 2 2. The process method as described in item 17 of the scope of patent application, wherein the reaction gas system of chlorine is selected from the group consisting of Cl2, HU, CxCly, CxHyCl, and combinations thereof. 2 3. The process method as described in item 22 of the scope of patent application, wherein the gas Page 21 1231528 6. Scope of patent application The reaction gas system is C 1 2. 24. The process method as described in item 23 of the scope of patent application, wherein the reaction gas of the gas further comprises an inert gas. 2 5. The process method as described in item 24 of the scope of patent application, wherein the inert gas is argon. 26. The process method as described in claim 25, wherein the C 1 fishing flow rate is between 5 and 4 0 0 sccm, and the argon flow rate is between 10 and 4 0 0 sccm. . 27. The process method as described in item 26 of the scope of patent application, wherein the reaction gas of chlorine further comprises a nitrogen component. 28. The process method as described in item 27 of the scope of patent application, wherein the nitrogen component uses N 拃 as a gas source. 2 9. — A method for avoiding the formation of residual photoresist in the interlayer / contact hole of the dual damascene structure, including at least the following steps: providing a substrate having an amine-containing material layer on the substrate; Forming a via hole / contact hole in the amine material layer; treating the via hole / contact hole with a chlorine-containing plasma; and filling the via hole / contact hole with a DUV photoresist to form a trench pattern Page 22 1231528 6. Scope of patent application. 30. The process method as described in item 29 of the scope of the patent application, wherein the step of treating with a plasma containing chlorine is used to reduce the amine component on the sidewall of the via / contact hole. 3 1. The process method as described in item 29 of the scope of the patent application, wherein the chlorine reaction gas system is selected from one of C 1 2, HC, C XC 1 y, C XH yC 1 and combinations thereof. 3 2 · The process method described in item 31 of the scope of patent application, wherein the reaction gas system of chlorine is C1 2. 33. The process method as described in item 32 of the scope of patent application, wherein the reaction gas of chlorine further comprises an inert gas. 34. The process method as described in claim 33, wherein the inert gas is argon. 35. The process method according to item 34 of the scope of patent application, wherein the C 1 fishing flow rate is between 5 and 40 0 seem, and the argon flow rate is between 10 and 40 Osccra. 36. The process method as described in item 35 of the scope of patent application, wherein the gas reaction gas further comprises a nitrogen component. Page 23 1231528 6. Scope of patent application 37. The process method described in item 36 of the scope of patent application, wherein the nitrogen component uses N 拃 as a gas source. Page 24