TW478097B - Manufacture method of barrier layer with sandwich structure - Google Patents

Abstract

This invention provides manufacture method of barrier layer with sandwich structure (titanium nitride, tantalum nitride and tungsten nitride) in semiconductor manufacture process to inhibit copper diffusion in copper metallization process. The inventive method introduces thin metal layer (titanium, tantalum and tungsten) or metal oxynitride layer (titanium oxynitride, tantalum oxynitride and tungsten oxynitride) to divide the original metal nitride into 2, 3 or 4 layers during the conventional metal nitride deposition process. Because the greater discrepancy of the crystalline structures, the thin sandwich layers can destroy the continuity of cylindrical crystalline structure of the initial single metal nitride layer and thus multiple layer interface separates the individual metal nitride layers to lengthen diffusion path of copper metal and reduce diffusion damage from copper metal. In the deposition system, the metal nitride layer, metal layer and metal oxynitride can be deposited in the same system through the change of sputter atmosphere of the sputter process.

Description

4 / 5UV / V. Description of the invention (1) The present invention relates to a 滁 / 苴 t t, especially about a kind of integrated electricity; * ϋ a method of forming a barrier layer, a special method. Manufacture of barrier layer with sandwich structure in circuit manufacturing process • fei, Yu ί 5: 'Summer heat stability and good electrical conductivity, refractory are all good nitrides (titanium nitride, gas 彳 μRu, metal materials ., lrfc, emulsification, nitrided crane) are the most common diffusion barriers used in the manufacturing process nowadays & A # U 丨 bulk circuit

d ^ ^ Early Composite Materials, but this material has an AI 'that phase 5 valleys easily form a columnar crystal structure (as shown in Figure 1), this columnar crystal structure is a fast barrier ability of barrier metals Degraded, and element characteristics are deteriorated. In view of this, the object of the present invention is to provide a gold-layer structure with a thin interlayer as a barrier layer in the integrated circuit manufacturing process to prevent the diffusion of metal during the manufacturing process. In order to achieve the above-mentioned object, the present invention proposes a structure with a thin interlayer of nitrogen ▲, (titanium nitride, tantalum nitride, tungsten nitride) as a barrier layer in an integrated circuit system to block copper metal. Copper metal diffusion during the chemical process. = Method: Through the deposition of a traditional metal nitride layer, through the intervention of a thin metal layer (^ titanium ^, button, tungsten) or a metal oxynitride layer (titanium oxide, nitrogen oxide ^, tungsten oxynitride), The original nitrided metal layer is divided into two and three layers. As far as the crystal structure is concerned, due to the large difference in crystal structure, this #reflective layer can find the continuity of the columnar crystal structure of the original single nitrided metal layer and show multiple layers of grain boundaries staggering the nitrided metal layer, extending and Turn the diffusion path of steel metal to reduce the diffusion damage of copper metal. The metal nitride layer, the metal layer, and the metal oxynitride layer can be changed in the same deposition system through the change of the sputtering atmosphere during the sputtering process.

Page 4 478097 V. Description of the invention (3) Prevent metal diffusion during metallization process. Please refer to M2 to FIG. 4, which show a manufacturing method of a barrier layer with a sandwich structure in the embodiment of the present invention. As shown in FIG. 2, this embodiment is applicable to a substrate. The substrate includes a Γ region, and the metal interconnects are 100. Here, the metal interconnects in the lower layer 100 are taken as an example, and the metal interconnects in the lower layer. On the surface, a flattened inner metal dielectric layer (IMD) or an inner insulating layer (ild) is formed on the surface. Here, the inner metal dielectric layer (IMD) is used as an example, and the commonly used inner metal dielectric layer (IMD) is used as an example. Electrical layer materials include one or more layers of silicon oxide, borosilicate glass, borophosphosilicate glass, or low dielectric constant materials (such as FLARE, pAE-2, FSG, hsq, etc.). Among them, since the damascene process is used to solve the problem of difficult etching of copper metal in the production of copper wires, one of the methods is to first etch out the underlying metal interconnections on the flat inner metal dielectric layer nQ. Trenches (or more including etched vias) 120 on the surface of the line 100. Next, please refer to Figure 3 and conformally form a metal nitride layer such as titanium nitride. Nitriding button or tungsten nitride 丨 30. Then refer to FIG. 4 to form a thin metal layer 140, such as titanium, tantalum, tungsten, or a metal oxynitride layer, with a thickness of 100 ^ Αγ. The metal layer knife is one, two, or four, etc., which can be performed in the same sputtering key cavity and two sputtering chambers in the same system. Due to the same sputtering deposition process, the sputtering atmosphere is adjusted by (Ar, Ν2) Into (Ar) or (Ar, N2, 02) and then back to (Ar, N2) or adjusted to (Ar) or (Ar, N2, 02) and then back to (Ar, N2) ... • 'As a titanium nitride barrier layer, it can be made by a thin titanium interlayer or a thin nitrogen oxide

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Page 6 0522-5702TW-ptd 478097 V. Description of the invention (4) The fluorinated layer = into the original titanium nitride barrier layer, which can result in a thin layer as shown in Figure 4: Three ... · Barrier structure of thin interlayer. The above method for manufacturing the barrier layer can be applied to both aluminum wires and tungsten plugs (W-plug). ^ Figure 5 t is a transmission electron microscope analysis picture, Figure 5A is a traditional gasification barrier layer, and Figure 5B is a titanium nitride barrier layer with interlayer titanium, showing that a thin layer of titanium can be successfully used. A barrier layer of titanium nitride (upper layer) / thin interlayer titanium / nitrium (lower layer) is formed. In this structure, the continuity of the 单一 -shaped crystal structure of the original single titanium nitride layer is destroyed, and multiple grain boundaries are present. Staggered titanium nitride metal layers. Figure 6 is the leakage current analysis chart. The analysis of the leakage current at the junction shows that at the temperature of 5 50 C '30 minutes after the annealing heat treatment failure test, copper will have a larger leakage in the traditional titanium nitride barrier layer. The current (Figure 6 A) is due to the diffusion into the Shixi substrate. Relatively speaking, in the structure of the gasification barrier layer with (double) interlayer titanium shown in Fig. 6β, the leakage current is still kept very low, which shows that its barrier ability is significantly improved. Figure 7 is a sheet resistance value analysis chart. The sheet resistance value analysis after annealing heat treatment at different temperatures for 30 minutes has also shown that the early layer of titanium nitride resist P with interlayer titanium has high thermal stability. Figure 8 is a scanning electron microscope analysis photo of the 1 / barrier layer / silicon substrate structure after the annealing treatment at 60 ° C and 30 minutes. Shows obvious damage (Figure 8A). Relatively, the titanium nitride barrier layer with inflammation layer has higher thermal stability or integrity (Figure 8B).

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478〇97 Description of the invention (5) Figure 9 shows the depth analysis of Auje Electronics after the copper / barrier layer / silicon substrate structure has been damaged by annealing and heat treatment. Auje Electronics analysis is shown after the heat treatment experiment. Interlayer titanium and titanium nitride barrier layers can reduce mutual diffusion. y Although the present invention has defined the invention with better practice, anyone familiar with this item on the way, but it is not used within the spirit and scope, can be changed and clouded, without departing from the essence of the invention. The scope of patent application = decoration, so the scope of protection of the present invention @ W shall prevail.

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Claims (1)

Case No. 89122418 6. Scope of patent application Repair 丨 1. The manufacture of a barrier layer with inflammatory layer structure ^ one by one = bottom, including the following steps: Method 'applicable to a nitride-based metal layer based on the substrate; for the nitrided metal At least one gold metal layer is formed in the layer to divide the nitrided metal layer into at least two or at least one oxynitride. 2. As described in the first patent application, the square metal layer is made of titanium nitride, nitride For buttons or tungsten nitride, 'The nitriding 3. If the patent, please apply for the first! The method described in item 5 is selected from titanium, buttons or tungsten. ’,. Hay metal 4. The method as described in item i of the patent application range, wherein the metallization layer is selected from titanium oxynitride, nitrogen oxynitride or tungsten oxynitride. 5. The method as described in item i of the scope of the patent application, wherein forming at least one metal layer or the at least one metal oxynitride layer is performed in the same system as the nitrogen " metallized layer, because of the same deposition In the manufacturing process, it is completed by adjusting the sputtering atmosphere. 6. The method according to item 5 of the scope of patent application, wherein the adjustment of the sputtering atmosphere is to adjust the sputtering atmosphere from (Ar, M to (Ar) or (Ar, N2, 02) and then back to (Ar, N2). ' 2-5702twfl.ptc Page 9