TW434865B - Etching process for reducing the contact resistance in the multi-layer structure - Google Patents

Abstract

A method for forming the contact in the multi-layer structure which includes the following steps: providing a substrate, there is a formed metal oxide semiconductor transistor on the upper surface and inside of the substrate, in which the transistor comprises a metal silicide covering thereon and forming a capping layer on the gate of the transistor; then, forming a dielectric and a photoresist on the substrate that the photoresist is used to define the contacts on the active region of the transistor and the gate; being the critical step, directly etching the planarized dielectric uncovered by the photoresist layer; and, using the etchant with high selectivity in the high density plasma etching machine to let the etching process stopped at the capping layer; and, directly etching the capping layer and using the etchant with high selectivity in the high density plasma etching machine to let the etching process stopped at the metal silicide layer.

Description

V. Description of the invention (1) 5 -1 Field of the invention: The present invention relates to a method for reducing the resistance value of a contact window, and in particular, to reducing the resistance value of a contact window in a multilayer structure (mu 11 i-1 ay er). Method of leakage current. BACKGROUND OF THE INVENTION In various fields in the fabrication of integrated circuits, contact window etching is a necessary step. For example, "a gold (polycrystalline oxide gate of MOS transistor) separated by a field oxygen region (fie 1 d ox i da ti on)" is covered with a planarized insulating layer or an interposer Electric submersible, such as Butterfly Phosphor Dream Glass (BPSG), Phosphor-Silicon Glass (PSG), Spin-Coated Silica Glass (S0G), Tetraoxyethyl Silicon, etc. (TE0S). In order to effectively connect the polycrystalline hard brake in the active area of the component It is necessary to pass through the interconnecting layer at the selected position. The opened contact window will be connected by the pattern-transferred metal. 〇2 5 micron technology requires a multilayer connection with low window resistance and low leakage current = window process ^ Due to the low selectivity of titanium oxides to silicon compounds, the current etching machines for reactive ic * n etcher (MERIE) oxides exhibit high contact window resistance values. If there is a titanium silicon compound residue in the contact window, a high leakage current will be caused. One solution is to require an additional p 1 ug implant step to compensate for silicon junction loss. As first

V. Description of the invention (2) Figure. Referring to FIG. 1A, a substrate is provided, in which a metal oxide semiconductor (MOS) is formed into two layers of gold to form a dielectric layer covering a semiconductor transistor and a semiconductor layer. Formation of instructions. However, carved by full money. One and then use the credit. Because of the need and the high cost, this crystal is formed inside and above the substrate 10. It is next to the oxidized layer 1 1 2A and 1 1 2B, and above 114. The 114 and 112A layers are the top of the gate of the metal oxide, and the 1 1 2 B layer is the top of the active region of the metal oxide. . Next, a planarization 0 and a photoresist layer 14 0 are formed, and a contact window hole () is defined. A conventional oxide etching machine etches the dielectric layer contact holes 1 30A and 1 30B. As the first B circle has a lower selection ratio, the metal silicide layer 1 1 2 B is finished. The solution is worn when the money is carved. Over-metal; implanted outside the epsilon layer 1 1 2 B to compensate for the loss of stone joints, as shown in the first C figure, N + and P + are implanted separately. This step requires two photoresistor leakage currents, and then forms A layer of adhesion 1 50. The procedure is more complicated. Objectives and Summary of the Invention: In the background of the invention described above, many disadvantages caused by the traditional contact window engraving technique are provided in the present invention, which provide the engraving technique for reducing the contact window resistance and leakage current.

Page 5 434865 V. Description of the invention (3) Another object of the present invention is to reduce the process cost and simplify the steps. Two ion implantation steps to lower according to this technique. First, ’one of the barriers on the gate. The contact between the titanium in the moving region of the photoresist layer and the formation of the fossil layer is also described above. The present invention provides a method of providing a metal oxide semiconductive silicon layer overlying a transistor and nitrogen. Into. Then formed on the substrate-on the gate and active area of the stone oxide crystal. Β, then, the silicon layer is not etched by the photoresist layer and etched through the window hole on the gate. When etching the oxide, the Qinhua dream layer that was not engraved on the gate was not etched. The most adherent layer is formed above the contact window hole. The substrate of the contact window etched body is a silicon silicon layer coating which is connected to the oxidized nitrided photoresist layer that is in contact with the contact lens. It is a light window hole that defines the hair Layer to main sand layer, because of the covered nitrogen conformation (5-4) A simple explanation: Figures A to C show a traditional etching connection, the schematic circle of each step; ⑷ contact self-made species Flow chart of each step; Figures 2A to 3D show the schematic diagrams of the steps of etching according to the present invention. Representative symbols of the main part in the strip solidification process 10 substrates page 6 5. Description of the invention (4) 2 0 dielectric layer 3 0 metal oxide layer 4 0 photoresist layer 5 0 adhesion layer 1 0 0 substrate 1 2 0 dielectric layer 1 2 2 insulating layer 1 3 0 metal oxide layer 1 4 0 Photoresist layer 1 5 0 Adhesive layer 5-5 Detailed description of the invention: The detailed embodiments of the invention are described next. However, it should be understood that the invention can be achieved with other obvious embodiments. The invention is not limited Special implementation ^ Π ^ —The diagram is a frank process of a method for forming a contact window according to the present embodiment. Ϊ́: an internal dielectric layer is formed on it and a silicon nitride layer is passed through the planar electrode; The transistor is formed on the substrate. The step of the transistor is to use a high-density electrode as a termination layer. Then the key dielectric layer is formed to contact the two-year-old 'with an etching sword with a high selectivity to straighten Etching silicon oxide and nitride = ^ 0 2. This etching step includes both because the remaining process has a high selection ratio, not $ 7 pages

There is an excessive amount of time, so there are fewer conditions suitable for the different steps in 'the formation of the contact layer of the contact window 2'. Semiconductor field-effect transistors, either deposition or mixed 0. The optimal thickness of this oxide layer is 30,000 angstroms and the thinnest is 15,000 angstroms. Deposited tetraoxosilicone, high-density Shi Xi 'Shed Shi Xi broken glass, atmospheric pressure chemical silicon, or any of its known shapes The main function is to provide the multilayer junction to form B' by any conventional method In the material examples of the metal oxide semiconductor layer 12A and 12B, the closed top region of the metal silicide layer 12A field-effect transistor is used as the top of the active region. It is not important that the present invention is contained in the substrate 10 in the second A picture, and the present invention is not understood. Subsequent embolic implantation steps. Ran 3. The steps mentioned in the second figure will be in the following third A to third containing integrated circuit structures, such as a metal oxide bottom layer 1 0 0, and a flat oxide layer 1 2 is formed on it by an oxidation method. 2 2 0 0 Angstroms, but the maximum thickness is about the same time. The oxide layer 120 may also be an oxygen-oxidized layer formed by an oxidative vapor deposition (APCVD) method formed by an electric paddle gain method (HDP). The inner dielectric layer in this oxide structure. A part of the 12F and 12 field-effect transistors of the metal lithotripsy layer. The metal stone is basically a titanium fossil. In the present embodiment, it is used as a metal oxide semiconductor field, and the metal oxide layer 1 2 B must be mentioned briefly here. The structure of the first element is formed, and these pairs cannot be described without detailed tracing details. Reason

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A cap layer 14 is formed on the metal silicide layer 128, and is used as an etching stop layer. The cover layer formed by the conventional chemical vapor deposition method is mainly a stack of silicon nitride or silicon oxynitride. After that, the photoresist layer is formed by any appropriate method, and the contact window pattern is transferred to the photoresist layer 40 at the position where the window hole is contacted. Electrical layer 2 Polymer over-etched Non-oxidized etc. Some alternatives are shown for polymers. Refer to the third figure B and 0. In order to achieve the etched layer, such as etching β in the hydrogen-containing high-density plasma-etched high-density plasma oxide pair, it will etch Shi Xi, Qin Shi Xi, silicon nitride, or develop this oxide, such as C {J2 Silicone / Nitrogen and Oxygen The third C picture 'in a dry #engraving method to engrav a rice' in an oxide dumpling engraving machine, with an etching ratio rich in carbon materials. Carbon-rich polymer oxides stop at the base compounds including silicon substrates, such as silicon nitride, titanium nitride, aluminum, and oxynitride. The key lies in the hydrogen-containing phase, with C4 F8. / C 0 / A r compound plus one F2, CH3F 'chf3, c2H2F4, etc., will manifest the silicon layer without silver titanate

, And ;, thermally reversing the 2 walls with alpha compounds. The decomposition of the oxide / Qin Shixiren 2 2 gas in the post-electrochemical process produces adjustment process parameters to select the ratio of the material to the oxide / silicon nitride through the degree of etching. The process has a high selection ratio. The bottom layer is used in the over-implantation step.

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Claims (1)

6. Scope of Patent Application 1. A method for forming a contact window without the need for embolization, the method includes at least: providing a substrate, the substrate having an formed metal oxide semiconductor transistor on and inside the substrate, Wherein the transistor has a metal silicide layer covering it, and a cover layer is formed on the gate of the transistor; a dielectric layer is formed on the substrate; a photoresist layer is formed on the dielectric layer, The photoresist layer defines a contact window on the active area and gate of the transistor; the planarized dielectric layer not directly covered by the photoresist layer is engraved directly, and has a high selection ratio in the plasma etching machine. The etchant stops the etching on the cover layer; and, directly etches the cover layer, and stops the etching on the conductor layer with a high selectivity etchant in a high-density plasma etching machine. Wherein the above-mentioned cover layer is at least, the above-mentioned cover layer is at least, and the above-mentioned conductor layer is at least 2. The method according to item 1 of the patent application scope includes a stacked layer of silicon nitride and silicon oxynitride. 3. The method according to item 1 of the patent application scope, comprising silicon oxynitride. 4 * The method according to item 1 of the patent application scope includes metal dreams β Page 11 ^ 34g〇5 6. Scope of patent application The step of covering the layer is completed by generating a hydrogen-containing polymer in a high-density plasma etching machine. 6. The method according to item 5 of the patent application, wherein the above-mentioned hydrogen-containing polymer is formed by the decomposition of CH2 F2 in a high-density plasma etching machine. 7. The method according to item 1 of the scope of patent application, wherein the step of directly etching the dielectric layer is completed by generating a carbon-containing polymer in a high-density plasma etching machine. 8. The method according to item 7 of the scope of patent application, wherein the above-mentioned carbon-containing polymer is produced in the wall of the thermal reaction chamber as C4F8 / CO / Ar / CH2F2. 9. The method of claim 1 further includes sputtering a conformal adhesion layer on the contact hole. 10. The method according to item 1 of the scope of patent application, further comprising planarizing the dielectric layer 11. The method according to item 1 of the scope of patent application, wherein the above-mentioned dielectric layer is oxidized. 12. A method for forming a contact window without the need for an embolization, the method comprising at least: Page 12 ^ -34865 VI. The scope of the patent application provides a substrate, the top of the substrate and the metal oxide semiconductor transistor 'which should be covered thereon, and a substrate formed on the substrate of the transistor's free electrode. A layer of stone oxide; on the silicon oxide layer, a photoresist layer crystal is formed on the active area and the gate defines a contact directly etched without being covered by the photoresist layer in a South Density Plasma Silver Engraver with a high selection ratio in the Cover layer; directly etch the cover layer, and the etching agent with a high selectivity ratio makes the etch formation-conformal adhesion layer at the contact; the inside has an already formed transistor with a chinite layer to form a cover layer; 'Wherein the photoresist layer is on the electrical window; the planarized dielectric layer, and the remaining agent makes the etching stop in the plasma etching machine with a high conductor layer; and on the hole. 13. If the 12th item of the scope of patent application does not contain the nitrided material, the method is as follows: the stack layer of silicon, /, lice gasified silicon, among which the above-mentioned cover layer is up to 14. If the scope of patent application is No. 12 Jg Contains little silicon oxynitride. Method, and middle, upper, and high-pass—Sheng $ /, T The above-mentioned coating layer to 15 ', as described in the patent application scope item 12, the steps of the coating layer, the method, the material to complete. … The density of the electric paddle is described directly in the insect engraving machine to generate hydrogen-containing polymerization 16. If the method of the scope of patent application No. 15, Gan 4 'It makes the above-mentioned hydrogen-containing polymerization 6. The scope of the patent application is in high-density electricity It is formed by the decomposition of ch2f2 in a slurry etching machine. For example, the method of claim 12 in the scope of patent application, wherein the above-mentioned step of directly etching the dielectric layer is completed by generating human-containing substances in a high-density plasma etching machine.口 18. The method according to item 17 of the scope of patent application, wherein the above carbon-containing material is generated in the wall of the thermal reaction chamber. , 0 further includes flattening the gasification 1 9. The method according to item 12 of the scope of patent application Sand layer.