Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
  • C23C14/14—Metallic material, boron or silicon
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
  • C23C14/14—Metallic material, boron or silicon
  • C23C14/18—Metallic material, boron or silicon on other inorganic substrates
  • C23C14/185—Metallic material, boron or silicon on other inorganic substrates by cathodic sputtering
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
  • C23C14/3407—Cathode assembly for sputtering apparatus, e.g. Target
  • C23C14/3414—Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
  • H10D30/00—Field-effect transistors [FET]
  • H10D30/60—Insulated-gate field-effect transistors [IGFET]
  • H10D30/67—Thin-film transistors [TFT]
  • H10D30/6729—Thin-film transistors [TFT] characterised by the electrodes
  • H10D30/6737—Thin-film transistors [TFT] characterised by the electrodes characterised by the electrode materials
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
  • H10D30/00—Field-effect transistors [FET]
  • H10D30/60—Insulated-gate field-effect transistors [IGFET]
  • H10D30/67—Thin-film transistors [TFT]
  • H10D30/6729—Thin-film transistors [TFT] characterised by the electrodes
  • H10D30/6737—Thin-film transistors [TFT] characterised by the electrodes characterised by the electrode materials
  • H10D30/6739—Conductor-insulator-semiconductor electrodes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
  • H10D30/00—Field-effect transistors [FET]
  • H10D30/60—Insulated-gate field-effect transistors [IGFET]
  • H10D30/67—Thin-film transistors [TFT]
  • H10D30/674—Thin-film transistors [TFT] characterised by the active materials
  • H10D30/6741—Group IV materials, e.g. germanium or silicon carbide
  • H10D30/6743—Silicon
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/40—Formation of materials, e.g. in the shape of layers or pillars of conductive or resistive materials
  • H10P14/42—Formation of materials, e.g. in the shape of layers or pillars of conductive or resistive materials using a gas or vapour
  • H10P14/44—Physical vapour deposition [PVD]
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/09—Use of materials for the conductive, e.g. metallic pattern
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12736—Al-base component

Definitions

• the present invention relates to an aluminum alloy thin film and a sputtering target material for forming the aluminum alloy thin film, and particularly to an aluminum alloy thin film having high heat resistance and low resistance which constitutes a thin film wiring of a liquid crystal display, an electrode, and a wiring of a semiconductor integrated circuit. , And a sputtering material suitable for forming an aluminum alloy thin film thereof.
• liquid crystal displays have been widely used as substitutes for so-called cathode ray tubes (CRTs), using computer display devices such as notebook computers as a typical example.
• CRTs cathode ray tubes
• TFT thin film transistor
• the required characteristics of the liquid crystal displays are becoming more severe.
• wiring materials with low specific resistance are required. The characteristic requirement of the specific resistance is to prevent the occurrence of a signal delay that occurs when the wiring is made longer and thinner.
• high melting point materials such as tantalum, chromium, titanium, and their alloys have been used as wiring materials for liquid crystal displays.
• high melting point materials have too high specific resistance, resulting in large screens. It is not suitable for high-definition liquid crystal display wiring. Therefore, aluminum has attracted attention as a wiring material because of its low specific resistance and easy wiring.
• aluminum has a relatively low melting point of 660 ° C, Is problematic in that respect. In other words, after forming an aluminum film on a substrate by sputtering and wiring, and then forming an insulating film by CVD, heat of 300 to 400 ° C. is applied to the processed aluminum thin film. At this time, bumps like hillocks are formed on the surface of the aluminum film.
• the present inventors have developed an aluminum alloy thin film containing carbon and manganese (see Japanese Patent Application Laid-Open No. 2000-33647).
• the aluminum alloy thin film containing carbon and manganese has extremely low generation of hillocks, has very low specific resistance characteristics, and is very suitable as a thin film constituting TFT.
• a TFT when configured as a switching element of a liquid crystal display, it is necessary to form a transparent connection between a typical ITO (Indium Tin Oxide) film and an aluminum alloy thin film by an atomic bonding. If an aluminum or aluminum alloy thin film is bonded directly on the ITO film, the aluminum is oxidized at the bonding interface and the ITO film is reduced, and the bonding resistance changes. It is known that this is a phenomenon caused by an electrochemical reaction caused by a difference in electrode potential between the aluminum or aluminum alloy thin film and the ITO film.
• ITO Indium Tin Oxide
• a high-melting-point material such as molybdenum is interposed as a barrier layer between the ITO film and the aluminum alloy thin film during ohmic bonding, that is, a laminated structure of the aluminum alloy thin film Z-molybdenum / ITO is formed. This is usually done. Since such a laminated structure leads to an increase in production cost, a TFT At present, there is a demand for an aluminum alloy thin film having characteristics that can improve the structure of the aluminum alloy. Disclosure of the invention
• the present invention has been made in view of the above-described circumstances, and enables an anodic junction directly to an ITO film, prevents mutual diffusion of silicon and aluminum, has a low specific resistance, and has excellent heat resistance. It is intended to provide a thin aluminum alloy film. Another object is to provide a sputtering target material suitable for forming an aluminum alloy thin film having such characteristics.
• the present inventors have studied various aluminum alloys containing carbon, and as a result, have found that the above-mentioned object can be achieved if the alloy composition of the aluminum alloy thin film is as follows. completed.
• the alloy composition of the aluminum alloy thin film is as follows. completed.
• at least one element of nickel, cobalt, and iron is 0.5 to 7.0 at%, and carbon is 0.1 to 3.0 at%.
• carbon is 0.1 to 3.0 at%.
• the balance is aluminum.
• electrode potential refers to the potential at which the oxidation rate and the reduction rate are equal and equilibrium in the oxidation-reduction reaction of a reactant, so-called equilibrium potential, or natural potential. However, in this specification, it means a self potential.
• the spontaneous potential refers to a potential shown with respect to the reference electrode in a state where no current is supplied to the measurement system, that is, when a certain reactant is immersed in an aqueous solution.
• the ITO film and the ohmic junction In this case, it is possible to directly bond to the ITO film without providing a high melting point material such as molybdenum as a barrier layer, which simplifies the TFT manufacturing process and reduces production costs. . Further, since the aluminum alloy thin film of the present invention has excellent heat resistance and low specific resistance, it is possible to form a wiring suitable for a large-sized or high-definition liquid crystal display.
• the aluminum alloy thin film of the present invention may contain any one element of nickel, cobalt, and iron, and may contain two or more of these elements. However, the content is preferably in the range of 0.5 to 7.0 at%, so that preferable characteristics can be realized. If the content is less than 0.5 at%, the electrode potential of the aluminum alloy thin film is significantly different from that of the ITO film, so that the aluminum alloy thin film cannot be directly bonded to the IT ⁇ film, and the heat resistance of the thin film becomes poor. descend. In addition, if it exceeds 7.0 at%, even if an aluminum alloy thin film is formed at a substrate temperature of 20 Ot, the specific resistance value is 20 ⁇ cm after heat treatment at 300 ° C for 1 hour in a vacuum. And it is no longer a practical wiring material for liquid crystal display applications.
• the range of 0.5 to 5 at% is more preferable. Within this range, a thin film having low specific resistance and good heat resistance is obtained, which is very suitable as a wiring material for a large-screen or high-definition liquid crystal display. .
• the range of 2.0 to 5.0 at% is more preferable.
• the carbon contained in the aluminum alloy thin film of the present invention can achieve good characteristics when the content is 0.1 to 3.0 at%. If the carbon content is less than 0.5 lat%, the effect of suppressing the generation of hillocks will be lost, and if it exceeds 3.0 at%, the specific resistance value will increase, and practical wiring for liquid crystal displays Cannot be formed.
• the aluminum alloy thin film of the present invention has a screen content of 0.5 to 2.0 at%. It is desirable to further include recon. It is known that when an aluminum alloy thin film is directly bonded to silicon, aluminum and silicon cause interdiffusion at the bonding interface (Reference: "VLSI Thin Film Technology", Publisher: Maruzen Co., Ltd., 1986 Year). Therefore, if silicon is contained in the aluminum alloy thin film in advance, mutual diffusion of aluminum and silicon can be effectively prevented. If the silicon content is less than 0.5 at%, the effect of preventing interdiffusion at the bonding interface is reduced, and if the silicon content exceeds 2.0 at%, wet etching is not performed. It is not preferable because silicon or a silicon precipitate becomes an etching residue.
• the above-described aluminum alloy thin film according to the present invention is very suitable as a wiring material for forming a thin film wiring of a liquid crystal display, an electrode, a wiring of a semiconductor integrated circuit, and the like.
• a TFT it is necessary to form an aluminum alloy thin film according to the present invention directly on an ITO film without forming a barrier layer of a high melting point material such as molybdenum and to form an ohmic junction. It is possible.
• TFT is formed, mutual diffusion between the aluminum alloy and silicon can be prevented.
• At least one element of nickel, cobalt, and iron is 0.5 to 7.0 & 1:%, and carbon is 0.1 to 3%. It is preferable to use a target material for forming an aluminum alloy thin film containing 0.5 at% and the balance being aluminum, and further use a target containing 0.5 to 2.0 at% of silicon. Is preferred. When a target material having this composition is used, a thin film having a composition similar to that of the target material can be easily formed by sputtering, although it depends on the film formation conditions.
• the formation of the aluminum alloy thin film according to the present invention is preferably performed by using the evening gate material having the above-described composition, but is not limited to the simple target material containing all the necessary elements in advance.
• the simple target material containing all the necessary elements in advance For example, on the surface of an aluminum-carbon alloy target material, nickel, iron, Alternatively, a composite target material in which a tip of a metal tip is embedded may be used, or a composite target material in which a chip such as a carbon chip or nickel is embedded on the surface of a pure aluminum target material may be used.
• a thin film within the composition range of the aluminum alloy thin film according to the present invention can be formed, and an optimum target material may be appropriately selected in consideration of a sputtering device, conditions, and the like.
• Table 1 lists the film compositions, the film specific resistance values, and the results of hillock generation state investigations for Examples 1A to 14A and Comparative Examples 1 and 2.
• the thin films having the respective compositions of Examples 1A to 14A shown in Table 1 were formed using the evening getters manufactured as follows.
• a 99.99% pure aluminum is charged into a carbon pipe (purity: 99.9%), and heated to a temperature range of 160 to 250 ° C.
• the aluminum was dissolved.
• the dissolution of aluminum by the carbon tube was performed in an argon gas atmosphere at atmospheric pressure. After maintaining at this melting temperature for about 5 minutes to produce aluminum-carbon alloy in the carbon tube, the molten metal was put into a carbon mold and left standing for natural cooling to produce.
• a lump of aluminum-carbon alloy produced in this carbon mold was taken out, a predetermined amount of aluminum and nickel having a purity of 99.9% was added, and the mixture was put into a carbon melting tube for re-melting at 800 ° C.
• the mixture was redissolved by heating to about 1 minute and stirred for about 1 minute. This re-dissolution was also performed in an argon gas atmosphere at an atmospheric pressure. After the stirring, the molten metal was poured into a copper water cooled mold to obtain a target material having a predetermined shape.
• the final target material size was ⁇ 100 mm ⁇ thickness 6 mm.
• the target material of each composition was prepared by the above-described manufacturing method, and the target material of each composition was used to form a film under the above-mentioned thin film forming conditions, thereby forming the thin film of each example shown in Table 1.
• the film composition of each thin film shown in Table 1 was determined by using ICP emission spectroscopy (inductively coupled plasma emission spectroscopy) for nickel, cobalt, iron, and silicon, and carbon was quantified using a carbon analyzer.
• the specific resistance of each thin film was measured with a four-terminal resistance measurement device (measurement current: 100 mA).
• the specific resistance was carried out immediately after sputtering (as- d 0 pe), respectively 1 hour heat treatment at 3 levels of each of the thin film-coated glass plate in a vacuum 3 00 ° C, 3 50 D C, 400 ° C, the The film resistivity after the heat treatment was measured. The results were as shown in Table 1.
• Example 1A A 1 -0.3C-1.2N i 100 6.18 6.32 4.57 4.03 XX
• Example 2 AA 1 -0.3C-2.3N i 100 8.66 6.99 4.86 4.08 XX XX
• Example 3 AA> 1 -0.3C-3.1N i 100 10.34 7.37 5.51 4.40 ⁇ ⁇ X
• Example 4 AA 1 -0.8C-0.9N i 100 6.73 6.78 6.12 4.23 ⁇ XX
• Example 5 AA 1 -0.8C-1.9N i 100 8.01 6.87 4.84 4.08 ⁇ ⁇ X
• Example 6 AA 1 -0.8C-3.2N i 100 11.80 7.26 5.12 3.97 ⁇ ⁇ X
• Example 7 AA 1 -1.9C-1.2N i 100 8.50 8.70 6.93 5.36 ⁇ XX
• Example 8 AA 1 -1.9C-1.7N i 100 10.70 9.26 5.96 5.01 ⁇ ⁇ X
• Example 9 AA 1 -1.9C-
• the aluminum alloy thin film containing cobalt (Examples 11A and 12A) and iron (Examples 13A and 14A) in addition to nickel has a slightly higher specific resistance immediately after sputtering, but the wiring material As a result, it has a practical specific resistance value, has little hillocks, and has excellent heat resistance, like nickel.
• Table 2 shows the results of Examples 1B to 14B and Comparative Examples 1B and 2B.
• the formation of each thin film shown in Table 2 was performed under the same conditions as in Table 1 except that the substrate temperature was 200 ° C. Further, the measurement of the specific resistance and the observation of the hillock occurrence state are the same as those described above, and the description thereof will be omitted.
• a thin film having a predetermined thickness (0.3 im) was formed on a glass substrate with each composition shown in Table 3, and the glass substrate was cut out to obtain a potential measurement sample. Then, the surface of the potential measurement sample was masked so as to expose an area corresponding to 1 cm 2 to form a measurement electrode.
• the spontaneous potential was measured using a 3.5% aqueous sodium chloride solution (solution temperature 27 ° C), and silver Z silver chloride as the reference electrode.
• I TO film serving as a counterpart of O one Mick junction I n 2 ⁇ 3 _ 1 0 wt% S ⁇ .
• the composition of the following was used.
• the spontaneous potential of the ITO film was about 100 OmV. It was confirmed that the value was about 155 OmV for a pure aluminum thin film and -1400 to 1-1500 mV for an aluminum-carbon alloy thin film. On the other hand, in the thin film of the aluminum carbon alloy containing nickel, cobalt, and iron, the self potential was in the range of about 1650 to 11000 mV, which was about the same as that of the ITO film.
• a pattern of the ITO electrode (lX20 mm, thickness 0.3 im) was formed, and a sample for measuring the junction resistance was prepared. Then, the sample for measuring the junction resistance was heat-treated in a vacuum at 250 ° C. for 1 hour, and the change in resistance at the junction between the aluminum alloy thin film electrode and the ITO film electrode was examined. As a result, in the case of the combination of pure aluminum (5N) and the ITO film, the junction resistance after heat treatment was about four times the junction resistance before heat treatment. On the other hand, it was found that the combination of a thin film containing a predetermined amount of nickel, cobalt, and iron in an aluminum alloy carbon alloy and an ITO film did not change the junction resistance after heat treatment from that before heat treatment.
• the aluminum alloy thin film of the present invention has the same level of natural potential as the ITO film, it is possible to directly form an ohmic junction with the ITO film and prevent mutual diffusion between silicon and aluminum. In addition, the specific resistance is small and the heat resistance is excellent.

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• 2001
  • 2001-09-18 JP JP2001283306A patent/JP2003089864A/ja active Pending
• 2002
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