TW424277B - Chemical etching method applicable in semiconductor process - Google Patents

Abstract

The present invention discloses a chemical etching method applicable in a semiconductor process, particularly a method for etching a polysilicon. The method comprises: using a mixed etching gas of SF6/C2F6 added into Cl2/HB4, and using a chemical etchant mainly containing F and a chemical etchant mainly containing C, to increase the etching rate of polysilicon and reduce the sidewall etching rate, thereby obtaining a better polysilicon profile and increasing the etching rate.

Description

V. Description of the invention (i) 5-] [Invention field method The present invention relates to a chemical etching method applied to semiconductor processes-2 Background of the invention In the past ten years or more, since the birth of the computer, random memory (kam The use of κ in a wide range of areas 'makes the demand increase rapidly. It is especially applicable to the information industry of computer hardware. At the same time, it is not only used in the information industry' It is also commonly used in large-scale integrated circuits (LSI) and very large-scale integrated circuits Circuits (VLSI) and very large integrated circuits (ULSI). No doubt, even in the next century, the process technology of random memory (RAM) still occupies a very important position in the information industry. In the process of random memory 'Especially in the production of dynamic random memory' With the advancement of process technology, the future component size will increasingly tend to minimize atomic size ° The current line width on the production line has reached the width of the sub-micron, such as 〇 · 18 microns. At the same time, the goal of manufacturing finished products is also toward the southern accumulation degree of semiconductors. In the process, 'Chemical Etching' is not an option. One of the missing steps. Generally, for thin film layers, the gaseous gas (CL) / hydrogen bromide (HBr) mixed gas is used as the etching gas in the process. Its advantage is that it has a good polymer / photoresist film selection ratio, but must avoid helium / oxygen (He / 〇2) mixing

Page 4 V. Description of the invention (2) ^ As the thickness of the product is increased by the layered film, when using an etching gas mainly composed of gas (C12) / > deodorized hydrogen (HBr), there will be The slow etching speed and the generation of slight reentry (Reentry), such as part 15 of the first diagram. The other marked parts as shown in the first figure are: 丨 丨 is a semiconductor substrate, 12 is a polycrystalline stone, 13 is an inorganic anti-reflection layer (Inorganic ARC), and 14 is a photoresist layer. According to this report, the etching rate for a 1 micron high capacitor is only 5 pieces per hour per reaction chamber. These slow etching speeds and the generation of slight reentry angles (Reentry) seriously affect the high requirements and high yield of the process. As mentioned above, in view of the need to improve and increase the process technology of random dynamic memory (DRAM), it is urgent to propose a new process method and structure to improve the above problems and improve the quality of components and their manufacturing efficiency. . 5-3 Purpose and summary of the invention: In the above background of the invention, "The traditional mixed gas mainly composed of chlorine (cl2) / hydrogen bromide / HBr) is used as an etching gas in the manufacturing process. Sulfur fluoride / sulfur fluoride is dagger / dagger) in a mixed gas of chlorine gas / edge hydrogen ((CL / HBr)); and a chemical silver etchant based on fluorine (F) and carbon ( C) The main chemical engraving agent. According to the method described above, the present invention provides a method for increasing polycrystals.

Page 5 77 " τί V. Explanation of the invention (3) The rate of hired insects (Sidewall has better vertical wheel's characteristics and advantages can be better & the attached drawings, detailed Shi Xi CPolysHicon) etching rate and reduction Side Etching Rate). This allows the polysilicon to profile and specifically increase the silver etch rate. In order to make the above description and other objects of the present invention obvious and easy to understand, the preferred embodiments and detailed descriptions are listed in the following 5-4 diagrams: The first picture shows the etching results of the traditional process. The second figure shows the results of the etching process. The representative symbols of the main parts of the present invention: 11, 21 semiconductor substrates 12, 22 polycrystalline silicon 13, 23 inorganic anti-reflection layer (Inorgani 14, 24 photoresist layer 15 and concave corner c ARC) 5-5 Detailed description of the invention: Will cooperate first with a show will be described later. The following is a description of the invention. The description of the present invention is for reference. Some variations and advantages of the present invention V. Description of the invention (4)-The preferred method of manufacturing will be discussed later. Furthermore, although the present invention is illustrated by several embodiments, these descriptions do not limit the scope or application of the present invention. And, although these examples; using a thin dielectric layer, it should be understood that "'the main part may be replaced by the relevant part. Therefore, the semiconductor element of the present invention does not limit the description of the structure. These elements include proof and applicability of the invention and presentation. Use only King I Even though the present invention has been described by way of example and by citing a preferred embodiment, the present invention is not limited to the illustrated embodiment. Previously though

Enumeration and narrative-specific implementations. Obviously, other equivalent changes or improvements made without departing from the spirit of the present invention should be included in the scope of patent application of the present invention. In addition, all other similar and approximate changes or modifications not completed without departing from the spirit of the present invention are also included in the scope of patent application of the present invention. At the same time, the scope of the present invention should be interpreted in the broadest definition so as to encompass all modifications and similar structures. 2. The etching result of the present invention as shown in the second figure. The labels in the figure are: 21 is a semiconductor substrate, 22 is polycrystalline silicon, 23 is an inorganic anti-reflection layer (Inorganic ARC), and 24 is a photoresist layer. The etched body of the present invention uses a Fine Adjusted ratio of sulfur fluoride / sulfur fluoride (^ ^), and is added at a uniform speed, and already contains a quantitative ratio of chlorine gas / hydrogen bromide (cl2 / HBr) The mixed etching gas is used as an etching gas. And then add it to the main

Page 7 Description of the invention (5) Chemical engraving process. Therefore, this method of engraving polycrystalline silicon with silver to form a random memory (RAM) capacitor: generally includes chlorine (cl2), hydrogen bromide (HBr), sulfur fluoride (SF6), and sulfurized sulfur (C2Fe) as an etching gas. Then, a chemical etching process including fluorine (F) as the main chemical etching agent and carbon (C) -containing chemical etching agent is added together to perform a chemical etching process. Among them, gas (C lz) and hydrogen bromide (HBr) are formulated in a certain mixing ratio to form sulfur difluoride (SF6) and sulfur fluoride (C2FS) in a certain mixing ratio. Chlorine j (fl2), evolved hydrogen (HBr), sulfur fluoride (SF6), and sulfur fluoride (C2F6) are formulated at a mixing ratio of rhenium. The mixing ratio determines the etching rate, thereby controlling the etching rate by controlling the mixing ratio. 'According to the method described above, a chemical etchant mainly composed of fluorine (F) can increase the etching rate of crystalline silicon (Polysi) and increase the etching speed. A chemical etchant based on s carbon (C) can reduce the sidewall etch rate (^ deWall Etching Rate) and at the same time reduce the re-concave angle (Reentry ^ This method has a good polymer / photoresist film The selection ratio enables the crystalline silicon to have a better vertical profile (Pr0file) to form an effective pure rth. And T specifically increases the etching rate. It can also improve the overall production rate of the wafer fab & Throughput. According to The above description is only within the scope of the equivalent patent application completed under the spirit of the present invention to limit the scope of the patent application model of the present invention. The preferred embodiments of the invention are not intended to be used; Or modifications should be included in

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Claims (1)

6. Scope of Shenyin Patent 1. A method for engraving polycrystalline stone (P 〇1 ysi 1 ic ο η), including at least: gas (Cl2); hydrogen bromide (HBr); sulfurized sulfur (SF6) ; And sulfur fluoride (C2 Fe) as an etching gas; with the addition of fluorine (F) -based chemical etchant; chemical engraving process with carbon (C) -based chemical etching process: Increase the polycrystalline stone eve (P 〇1 ysi 1 ic ο η) meal rate and reduce the side edge engraving rate CSidewal 1 Etching Rate; and make polycrystalline eve can have a better vertical profile (P r 〇fi 1 e) and specifically increase the meal rate ^. 2. The method according to item 1 of the scope of patent application, wherein the above-mentioned chlorine gas (c2) and hydrogen bromide (HBr) are formulated in a certain mixing ratio. 32. The method according to item 1 of the scope of the patent application, wherein the above-mentioned sulfur fluoride (s) and sulfur fluoride (C: 2 F6) are formulated at a certain mixing ratio. 4. The method according to claim 1 of the patent scope, wherein the above-mentioned chlorine gas (C 12), hydrogen bromide (HBr), sulfur fluoride (SFe) and sulfur fluoride are mixed at a predetermined mixing ratio. Sixth, the scope of patent application 6. —A method of etching polycrystalline silicon to form random memory (RAM) capacitors at least includes: a method of 'gas (C 12); desertified hydrogen (Η B r); sulfur fluoride (SFe); and sulfur fluoride (C2 Fs) is used as an etching gas; it is added with a chemical etchant mainly composed of fluorine (F); a chemical etching process is performed together with a chemical etchant mainly composed of carbon (C) to increase polycrystalline silicon (P〇). 1 y S 丨 丨 i C〇n) and the reduction of the side etch rate (Sidewal 1 Etching Rate); so that polycrystalline silicon can have a better vertical profile (pr 〇fi 丨 e) and specifically increase the contact Carved rate. . 7. The method according to item 6 of the patent application, wherein the above-mentioned chlorine gas (Cl2) and hydrogen bromide (HBr) are prepared in a certain mixing ratio. 8. For the method of claim 6 in the scope of patent application, wherein the above-mentioned sulfur fluoride (SF6) and gasified sulfur (QF6) are formulated in a certain mixing ratio. 9. ^ The method of claim 6 in the scope of patent application, wherein the above-mentioned chlorine gas (cl2), hydrogen bromide (HBr), sulfur fluoride (SFe), and sulfur fluoride (QFj) are prepared in a certain mixing ratio. Page 10 6. Scope of Patent Application 10. The method of item 7 or 8 or 9 of the scope of patent application, wherein the above-mentioned mixing ratio determines the etching rate, thereby controlling the insect-saving rate by controlling the mixing ratio. 11. A gas for etching polycrystalline silicon, including at least: chlorine (Cl2); hydrogen bromide (ΗBr); sulfur fluoride (SF6); and sulfur fluoride (C2 F6) as an etching gas. 12. The gas in item 11 of the scope of patent application, wherein the above-mentioned chlorine gas ((: 12) and desertified hydrogen (HB r) are formulated in a certain mixing ratio. 1 3. The base poison in item 11 of scope of patent application The above-mentioned sulfur fluoride (SF6) and sulfur fluoride (C2 Fe) are prepared in a certain mixing ratio. 14. For example, the above-mentioned chlorine gas (Cl2), odorized hydrogen (Η B r), Reduced sparse (S F6) and sulfur fluoride (C2 F6) in a certain mixing ratio to make 15. If the scope of the application for patent No. 12 or 1 3 or 14 Chinese mixed The combined ratio determines the etching rate, thereby controlling the etch rate by controlling the mixing ratio. Page 11 VI. Application Patent Range 16, Kind of etching polycrystalline silicon to form random memory (RA body, at least: gas (ci2); hydrogen bromide (HBr); sulfur fluoride (SF6); and sulfur fluoride (C2) is used as an etching gas. 17 The gas according to item 16 of the patent scope, wherein the above-mentioned chlorine gas (Cl2) is mixed with a stink gas (HBr) at a certain mixing ratio. Item 1 and sulfur fluoride (C2 Fe) in a certain mixing ratio > > 1 9. As the above-mentioned sulfur fluoride (SF6) in item 6 of the patent application scope, the above-mentioned ^ The above-mentioned gas (Cl2), hydrogen bromide (HBr), sulfur fluoride (SFe) and sulfur fluoride ((6)) are prepared in a certain mixing ratio. The above-mentioned mixing ratio in item ^. AV 7 ^ N of 19 items determines the silver engraving rate, thereby controlling the money engraving rate by controlling the mixing ratio. Page 12