# US 2010/0167540 A1 · Film Forming Method, Plasma Film Forming Apparatus and Storage Medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0167540 A1 - Document ID: US20100167540A1 - Status: Published application - Kind: A1 - Application number: 12/223,781 - Filed: 2007-02-09 - Published: 2010-07-01 - Earliest claimed: 2006-02-09 - Assignees: Tokyo Electron Limited - Inventors: Takashi Sakuma; Taro Ikeda; Osamu Yokoyama; Tsukasa Matsuda; Tatsuo Hatano; Yasushi Mizusawa - Web page: https://patentgrep.com/patent/US20100167540A1 ## CPC - C23C 14/046: {Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates} - H01J 37/321: {the radio frequency energy being inductively coupled to the plasma} - H01J 37/34: operating with cathodic sputtering (H01J37/36 takes precedence {; methods of cathodic sputtering C23C14/34}) - H10P 14/44: Physical vapour deposition [PVD] - H10W 20/035: {combinations of barrier, adhesion or liner layers, e.g. multi-layered barrier layers} - H10W 20/056: {by filling conductive material into holes, grooves or trenches} - H10W 20/059: {by reflowing or applying pressure} - 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 (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract Disclosed is a technique for embedding metal in a recess provided in the surface of a process object, such as a semiconductor wafer W, only by plasma sputtering. The metal is copper as a typical example. The recess has a microscopic hole or trench having a diameter or width of 100 nm or less as a typical example. A film forming step and a diffusion step are alternately performed a plurality of times. The film forming step deposits a small amount of a metal film in the recess. The diffusion step moves the deposited metal film toward the bottom portion of the recess. In the film forming step, bias power to be applied to a stage for supporting the wafer W is set to a value ensuring that, on the surface of the wafer W, the rate of metal deposition due to the drawing-in of metal particles is substantially equal to the rate of the sputter etching by plasma. In the diffusion step, the wafer W is maintained at a temperature which permits occurrence of surface diffusion of the metal film deposited in the recess. ## Claims ### Claim 1 A film forming method, comprising: a step of placing a process object on a stage disposed in a process vessel, the substrate having a surface and a recess opening into the surface; a film forming step including a step of generating metal particles in the process vessel by generating plasma in the process vessel, by sputtering a metal target disposed in the process vessel by the plasma, and by applying bias power to the stage to draw the metal particles into the recess and deposit the metal particles in the recess, thereby embedding the recess with a metal, wherein the film forming step is performed under conditions that the bias power is set such that, on the surface of the process object, a deposition rate which is a rate of metal deposition caused by drawing-in of the metal particles is substantially equal to an etch rate which is a rate of sputter etching caused by the plasma; a diffusion step that maintains the process object at a predetermined temperature ensuring that surface diffusion occurs in a metal film deposited in the recess under conditions that no metal particles generated from the metal target, thereby to move metal atoms constituting the metal film toward a bottom portion of the recess; and a step of alternately and repeatedly performing the film forming step and the diffusion step a plurality of times. ### Claim 2 (depends on 1) The method according to claim 1, wherein the bias power is of a level ensuring that a base layer, which has been formed on surfaces of the recess before said film forming method is performed, is not etched. ### Claim 3 (depends on 1) The method according to claim 1, wherein the predetermined temperature is lower than any temperatures at which volume diffusion of the metal atoms constituting the metal film occurs. ### Claim 4 (depends on 1) The method according to claim 1, wherein, in the diffusion step, the process object is heated by collision energy generated by collision of plasma with the process object. ### Claim 5 (depends on 1) The method according to claim 1, wherein the diffusion step is performed in the process vessel in which the film forming step is performed. ### Claim 6 (depends on 1) The method according to claim 1, wherein the recess comprises a groove having a width of 100 nm or less, or a hole having a diameter of 100 nm or less. ### Claim 7 (depends on 1) The method according to claim 1, wherein thickness of the metal film formed in each of the film forming steps is 5 nm or less. ### Claim 8 (depends on 1) The method according to claim 1, wherein the recess comprises a groove for wiring or a hole for wiring. ### Claim 9 (depends on 1) The method according to claim 1, wherein the metal film is made of copper or a copper alloy. ### Claim 10 (depends on 9) The method according to claim 9, wherein the predetermined temperature in the diffusion step is in a range of 200° C. to 400° C. ### Claim 11 (depends on 1) The method according to claim 1, wherein the recess has a relatively small lower space and a relatively large upper space, said method further comprising a plating step that embeds the upper space with a plating after the lower space is embedded with the metal film by repeatedly performing the film forming step and the diffusion step. ### Claim 12 (depends on 1) The method according to claim 1, wherein: the recess has a relatively small lower space and a relatively large upper space, and both the lower space and the upper space are embedded with the metal film by repeatedly performing the film forming step and the diffusion step. ### Claim 13 A film forming apparatus comprising: a process vessel adapted to be evacuated; a stage for placing a process object thereon; gas introducing means for introducing a process gas into the process vessel; a plasma source for generating plasma in the process vessel; a metal target disposed in the process vessel; a direct current power supply for supplying power for discharge to the metal target; a bias power supply for supplying bias power to the stage; and an apparatus controller for controlling whole operations of said film forming apparatus, wherein the apparatus controller is configured to control said film forming apparatus to cause said film forming apparatus to perform: a film forming step including a step of generating metal particles in the process vessel by generating plasma in the process vessel, by sputtering a metal target disposed in the process vessel by the plasma, and by applying bias power to the stage to draw the metal particles into a recess formed in a surface of the process object and deposit the metal particle in the recess, thereby embedding the recess with a metal, wherein the film forming step is performed under conditions that the bias power is set such that, on the surface of the process object, a deposition rate which is a rate of metal deposition caused by drawing-in of the metal particles is substantially equal to an etch rate which is a rate of sputter etching caused by the plasma; a diffusion step that maintains the process object at a predetermined temperature ensuring that surface diffusion occurs in a metal film deposited in the recess under conditions that no metal particles generated from the metal target, thereby to move metal atoms constituting the metal film toward a bottom portion of the recess; and a step of alternately and repeatedly performing the film forming step and the diffusion step a plurality of times. ### Claim 14 (depends on 13) The apparatus according to claim 13, wherein the stage has means for cooling the process object. ### Claim 15 (depends on 13) The apparatus according to claim 13, wherein the stage has means for heating the process object. ### Claim 16 (depends on 13) The apparatus according to claim 13, wherein a gas groove, through which a thermally conductive gas flows, is provided in the surface of the stage. ### Claim 17 A storage medium storing a program for controlling a film forming apparatus, the film forming apparatus including: a process vessel adapted to be evacuated; a stage for placing a process object thereon; gas introducing means for introducing a process gas into the process vessel; a plasma source for generating plasma in the process vessel; a metal target disposed in the process vessel; a direct current power supply for supplying power for discharge to the metal target; a bias power supply for supplying bias power to the stage; and an apparatus controller in a form of a computer for controlling whole operations of said film forming apparatus, wherein the apparatus controller, upon execution of the program, controls the film forming apparatus to perform a film forming method, the film forming method including: a film forming step including a step of generating metal particles in the process vessel by generating plasma in the process vessel, by sputtering a metal target disposed in the process vessel by the plasma, and by applying bias power to the stage to draw the metal particles into a recess formed in a surface of the process object and deposit the metal particle in the recess, thereby embedding the recess with a metal, wherein the film forming step is performed under conditions that the bias power is set such that, on the surface of the process object, a deposition rate which is a rate of metal deposition caused by drawing-in of the metal particles is substantially equal to an etch rate which is a rate of sputter etching caused by the plasma; a diffusion step that maintains the process object at a predetermined temperature ensuring that surface diffusion occurs in a metal film deposited in the recess under conditions that no metal particles generated from the metal target, thereby to move metal atoms constituting the metal film toward a bottom portion of the recess; and a step of alternately and repeatedly performing the film forming step and the diffusion step a plurality of times.