TW439213B - Process of copper adhesion/barrier layer - Google Patents

Abstract

A processing for copper adhesion/barrier layer which is applied for a substrate that the steps includes firstly forming titanium nitride precursor containing carbon and hydrogen on the substrate; and, conducting in-situ nitrogen/silicon methane plasma processing on the titanium nitride precursor containing carbon and hydrogen to form a silicon titanium nitride layer as the copper adhesion/barrier layer; therefore, it provides better barrier characteristic for copper diffusion effect.

Description

V. Description of the invention (1) The present invention relates to a copper adhesion / diffusion iayer process, and particularly to a copper adhesion / barrier layer that forms a titanium nitride layer to prevent copper diffusion. Process. With the increasing demand for high-performance integrated circuits, the size design of circuit components has been reduced as much as possible to achieve the best performance. For example, when the gate length of the rib 3 transistor decreases to less than 0.25um (Sub-halfiicron), the switching speed of the transistor will also increase significantly. Therefore, in order to make full use of the increased speed of the transistor, the metal interconnects must have excellent electrical conductivity to facilitate transmission. In fact, the performance of advanced integrated circuit components is often limited by the conductivity of the metal interconnects, which are coupled to each component of the integrated circuit. In the past, aluminum (A1) and its alloys were the most widely used materials in the interconnection process. However, as the size of integrated circuit components has been shrinking, the number of interconnect components has continued to increase. This has led to a large demand for narrow interconnect ieads, and has also limited the application of aluminum and f alloys in next-generation integrated circuits. In addition, the high electrical resistance characteristics of aluminum and its alloys prevent it from developing β χ In view of this, many other metals (such as gold, silver, and copper) have been reconsidered as alternatives to aluminum and its alloys. Product. Among them, copper (Cu) is considered to be one of the best substitutes for aluminum and its alloys because of its low resistance and good electromigration resistance. However, copper easily diffuses 1 (difiusion) in integrated circuit materials and is not easily adhered to other metals / dielectric layers (germanium

V. Description of the invention (2)】 The shortcomings of the golden tin t t1, mouse silicon layer ...) make it unable to directly respond to the manufacturing process, and must require special treatment or provide additional attachments / barrier layers. use. At present, the technology of metal interconnects using copper as a CM0S element has not been developed. It is necessary to increase the adhesion and avoid damage to the semi-ordinary under the steel + the following inner interconnects or device areas. An additional adhesion / barrier layer must be formed between them to prevent the copper metal layer from diffusing to the underlying interconnects or device areas and react with it, and add copper gold (TaN) or titanium nitride (TiN), etc. , And its ability to prevent the diffusion of the copper metal layer still needs to be improved. The present invention proposes a process-compatible copper adhesion / barrier layer process suitable for a substrate. The steps are to form a titanium nitride precursor containing carbon and hydrogen on the substrate, and then The titanium nitride precursor is subjected to a nitrogen / siloxane plasma treatment in an in-situ to form a silicon silicon nitride layer as a copper adhesion / barrier layer. The invention further proposes a process-compatible copper adhesion / barrier layer process. The step is to form a carbon and hydrogen-containing titanium nitride on the substrate after forming a carbon-and-hydrogen-containing nitride precursor. The precursor is subjected to a nitrogen / hydrogen plasma treatment to 'form a nitrided drinking layer', and then the titanium nitride layer is subjected to a post-plasma plasma treatment or post-silicon thermal annealing ( thermal anneal ing) process to form a titanium silicon nitride layer as a copper adhesion / barrier layer. Among them, since a silicon-containing titanium nitride is provided as a silicon

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5. Description of the invention (3) Better barrier characteristics. This kind of steel adhesion / barrier layer process has a barrier layer, and therefore has a copper diffusion phenomenon as follows. One embodiment of the present invention will be described with reference to the drawings. Schematic diagram Copper adhesion / barrier layer. Figure 图% / shows the process of the embodiment of the present invention. [Explanation of symbols] -130 ~ 170 semiconductor substrate ~ 100; dielectric layer ~ 110; interlayer window ~ 120; precursor, titanium silicon nitride layer ~ 140, 160; silicon nitride layer ~ 150. Copper Metal Layer Embodiments Refer to FIGS. 1 to 5, which show a copper adhesion / barrier layer process in an embodiment of the present invention.蚺 Refer to FIG. 1, this embodiment is applicable to a substrate. The substrate includes a lower device area or a metal interconnect 100. Here, the lower metal interconnect 100 is used as an example. In addition, the lower metal interconnect is connected. On the surface, a flat inner metal dielectric layer (IMD) or an inner insulating layer (ILD) IIO is formed on the surface. Here, an inner metal dielectric layer (IMD) is used as an example, and a common inner metal dielectric layer is used. Materials include one or more layers of silicon oxide, borosilicate glass, borofilled silica glass, or low-k dielectric materials (such as flare, pAE_2, FSG, HSQ, etc.). In 1 since the damascene process is used to solve the problem of difficult etching of steel metal in the production of copper wires, one of the methods is to first etch the exposed metal on the flat inner metal dielectric layer n0. Trenches (or more including etched vias) 120 on the surface of the interconnect 100.

5. Explanation of the invention on page 6 (4) Next, referring to FIGS. 2 to 3, a titanium nitride precursor 130 containing carbon and hydrogen is conformably formed in the interlayer window 120 and extends to the inner metal dielectric layer ( IMD) 110 surface, and then treat the titanium nitride precursor (Precursor: TiCxNyHz) 130 containing hydrogen and hydrogen with a nitrogen / silicon methane (N2 / SiH4) slurry treatment in the same environment (in-si1; u) A titanium silicon nitride layer 14 0 ′ is formed as a copper adhesion / barrier layer. For example, a metal organic chemical vapor deposition process (M0CVD) is used to deposit a precursor such as TDMAT (tetrakis (dimethylamido) titanium) or TDEAT (tetrakis (diethylamido) 〇titanium) 130 while heating the substrate to a process temperature as usual. Within the interlayer window 120 and extending to the surface of the internal metal dielectric layer (IMD) 110, then the precursor 13 is subjected to a nitrogen / silicon methane (N2 / SiH4) under in-situ conditions. After the plasma treatment, the by-products formed are removed to form a titanium silicon nitride layer (T i S i [0140] as a copper adhesion / barrier layer.

Please refer to Figs. 4A to 4B ', which shows another embodiment of the present invention. First, as shown in Fig. 2, first conformally formed-a titanium nitride precursor containing carbon and hydrogen 130 in the interlayer window 120 and Extending to the inner metal dielectric layer (IM1)) 11 surface and then performing a nitrogen / hydrogen (] ^ 2 / {12) charge on the titanium nitride precursor 130 containing hydrogen and hydrogen according to FIG. 4A. Plasma treatment 'forms a titanium nitride layer 15o, and then performs a post-plasma treatment or post-silicon thermal annealing on the titanium nitride layer 150 according to FIG. 4B'. (Thermal anneal i ng) treatment, a titanium silicon nitride layer 16 is formed as a copper adhesion / barrier layer. For example, using a metal organic chemical vapor deposition process (MO C v))), when the substrate is heated to a process temperature such as 300 ° C, a

Page 7 V. Description of the invention (5) Antecedents 130 such as TDHAT (tetrakis (dimethylamido) titanium) or TDEAT (tetrakis (diethylamido) ti1; anium), etc. 130 in the interlayer window 120 and extend to the inner metal dielectric layer (IMD) ll10 surface, and then nitrogen / hydrogen plasma treatment of this precursor 130 according to FIG. 4A, after forming the by-products to remove a titanium nitride layer 150, and then according to FIG. 4B, nitriding The titanium layer 150 is subjected to post-plasma plasma treatment or thermal annealing treatment to form a polysilicon nitrided layer 160 as a copper adhesion / barrier layer. Finally, please refer to FIG. 5, after the copper adhesion / barrier layer 160 of the titanium silicon nitride layer is formed, chemical vapor deposition (CVD) and physical vapor deposition are used.

(PVD) or Eiectroplating method performs a comprehensive copper deposition on the inner metal dielectric layer 110 and fills the trench with copper. For example, an ionized metal plasma (IMP) can be used to deposit a seed layer, and then the copper conductive layer is deposited by electroplating. After the copper deposition is completed, the inner metal dielectric layer 110 is used as the polishing end point. Chemical mechanical polishing removes the excess metal copper to obtain the upper copper metal interconnect 170. Since the present invention further provides a silicon-containing titanium nitride as an adhesion / barrier layer between the upper copper metal interconnect 170 and the inner metal dielectric layer 110 and the lower semiconductor elements, therefore, for preventing copper metal The diffusion barrier characteristics can be further improved. Although the present invention has been defined by a preferred one, anyone familiar with this spirit and scope should have some protection scope as the attached patent

The embodiment is disclosed as above, but it is not a skilled person, and it does not deviate from the refinement and retouching of the present invention, so what is defined by the scope of the present invention shall prevail.

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Claims (1)

i439213 6. Scope of patent application I. A copper adhesion / barrier layer process is applicable to a substrate, including the following steps: (a) forming a titanium nitride precursor containing hydrogen and hydrogen on the substrate; and (b) The carbon / hydrogen-containing titanium nitride precursor is subjected to a nitrogen / silicon methane plasma treatment under the same environment (Un-Situ) to form a silicon silicon nitride layer as a steel adhesion / barrier layer. 2. The process as described in item 1 of the scope of patent application, wherein the titanium nitride precursor containing carbon and hydrogen is TDMATT. 3. The process as described in item 1 of the scope of patent application, wherein the titanium nitride precursor containing carbon and hydrogen is TDEAT. 4. A copper adhesion / barrier layer process suitable for a substrate, comprising the following steps: (a) forming a titanium nitride containing carbon and hydrogen on the substrate; (b) forming the carbon and hydrogen containing A titanium nitride precursor is subjected to a nitrogen / hydrogen plasma treatment to form a titanium nitride layer; and (C) the titanium nitride layer is subjected to a post (P0St) silicon methane plasma (pi asma) treatment. 'Form a titanium silicon nitride layer as a steel adhesion / barrier layer. 5 * The process as described in item 4 of the scope of patent application, wherein the titanium nitride precursor containing carbon and hydrogen is TDMAT. 6. The process according to item 4 of the scope of patent application, wherein the carbon and hydrogen-containing titanium nitride precursor is TDEAT. ?, A copper cladding / barrier layer process is suitable for a substrate, including the following steps: a) forming a titanium nitride precursor containing carbon and hydrogen on the substrate; Page 9 6. Scope of patent application (b) A nitrogen / hydrogen plasma treatment is performed on the carbon and hydrogen-containing titanium nitride precursor to form a titanium nitride layer; and (C) the titanium nitride layer A post thermal annealing annealing process is performed to form a titanium nitride layer as a steel adhesion / barrier layer. 8. The process according to item 7 of the scope of patent application, wherein the titanium nitride precursor containing carbon and hydrogen is TDMAT. 9. The process according to item 7 of the scope of patent application, wherein the titanium nitride precursor containing carbon and hydrogen is TDEAT. 0503-4993TTV.ptd Page 10