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EP-3396016-B1 - FILM FORMATION APPARATUS AND FILM FORMATION METHOD

EP3396016B1EP 3396016 B1EP3396016 B1EP 3396016B1EP-3396016-B1

Inventors

  • JIDAI, HIDETAKA
  • MATSUDA, RYOJI

Dates

Publication Date
20260513
Application Date
20161207

Claims (8)

  1. A film formation apparatus (1;2) for forming a multilayer film including {n + 1} or more layers, wherein n represents a positive integer of 1 or larger, the film formation apparatus (1;2) comprising: a rotational body (10;14) that is configured to rotate while supporting a to-be-film-formed material (50,52,54); a film formation mechanism (20) that is configured to perform a film formation process on the to-be-film-formed material (50,52,54); a monitor mechanism (30) that is configured to monitor the rotational speed of the rotational body (10) and a control mechanism (40) that is configured to control rotation of the rotational body (10;14), wherein the control mechanism (40) is configured to calculate a number of rotations of the rotational body (10;14) from a desired layer thickness of a layer of the multilayer film, a default forming rate of the film formation mechanism (20) and a default rotational speed of the rotational body (10;14), and to adjust the rotational speed of the rotational body (10;14) in such a way as to make the calculated number of rotations of the rotational body (10;14) closer to an integer, and wherein in a first alternative the control mechanism (40) is configured to in the step of adjusting the rotational speed of the rotational body (10), grasp the rotational speed of the rotational body (10) for an n th layer from a result of the monitoring by the monitor mechanism (30), and to adjust the rotational speed of the rotational body (10) for an {n + 1} th layer and/or a following layer, wherein n represents a positive integer of 1 or larger; and wherein the control mechanism (40) is configured to set a measurement interval t [sec] of the monitor mechanism (30) and a number of rotations A of the rotational body (10) required for one measurement in such a way as to satisfy a conditional formula: {Ra 2 × t × da} / {60 × {60 × s × A + Ra × t × s}} ≤ 0.05, wherein Ra represents the rotational speed [rpm] of the rotational body (10) for the {n + 1} th layer, da represents the desired layer thickness [nm] of the {n + 1} th layer, and s represents the forming rate [nm/sec] of the film formation mechanism (20); and in a second alternative the to-be-film-formed material includes a number of substrates (50,52,54); wherein the number of substrates is divided into plural sections; the control mechanism (40) is configured to, in the step of adjusting the rotational speed of the rotational body (10), grasp the rotational speed of the rotational body (1 O) for an m"'1 section of an nu'I layer from a result of the monitoring by the monitor mechanism (80), and to adjust the rotational speed of the rotational body (10) for an {m + IF" section and/or a following section at the n"'1 layer, wherein m represents a positive integer of 1 or larger, and wherein the control mechanism (40) is further configured to set a measurement interval t [sec] of the monitor mechanism (30) and a number of rotations A of the rotational body (1 0) required for one measurement in such a way as to satisfy a conditional formula: Rc 2 × t × dc / 60 × 60 × s × A + Rc × t × s ≤ 0.05 wherein Rc represents the rotational speed [rpm] of the rotational body (10) for the {m + l) th section and/or a following section of the n th layer, dc represents the desired layer thickness [nm] of the n th layer; and s represents the forming rate [nm/sec] of the film formation mechanism (20).
  2. The film formation apparatus (1) according toclaim 1, wherein the control mechanism (40) is configured to adjust a forming time or the forming rate of the film formation mechanism (20) in such a way as to make the calculated number of rotations of the rotational body (10) closer to the integer.
  3. The film formation apparatus (1) according to any one of claims 1 or 2, comprising a detection mechanism (60) that is configured to detect a reference point (12) of the rotational body (10), wherein the control mechanism (40) is configured to adjust a rotational position of the rotational body (10) based on a result of the detection by the detection mechanism (60) such that formation of each layer starts at the reference point (12) of the rotational body (10), finishes at the reference point (12) of the rotational body (10), or starts and finishes at the reference point (12) of the rotational body (10).
  4. The film formation apparatus (1) according to any one of claims 1 to 3, comprising a second film formation mechanism (70) that is configured to perform the film formation process on the to-be-film-formed material (50), wherein the control mechanism (40) is configured to adjust the rotational speed of the rotational body (10) in such a way as to make the calculated number of rotations of the rotational body (10) closer to the integer even in a time slot (82) for shifting from formation of the multilayer film to formation of a next multilayer film.
  5. A film formation method for forming a multilayer film including {n + 1} or more layers, wherein n represents a positive integer of 1 or larger, using a film formation apparatus (1;2) including a rotational body (10;14) that rotates while supporting a to-be-film-formed material (50,52,54), and a film formation mechanism (20) that performs a film formation process on the to-be-film-formed material (50,52,54), a monitor mechanism (30) that monitors the rotational speed of the rotational body (10); the film formation method comprising: controlling rotation of the rotational body (10;14), calculating a number of rotations of the rotational body (10;14) from a desired layer thickness of a layer of the multilayer film, a default forming rate of the film formation mechanism (20) and a default rotational speed of the rotational body (10;14), and adjusting the rotational speed of the rotational body (10;14) in such a way as to make the calculated number of rotations of the rotational body (10;14) closer to an integer, wherein in a first alternative the film formation method comprises, in the step of adjusting the rotational speed of the rotational body (10), grasping the rotational speed of the rotational body (10) for an n th layer from a result of the monitoring by the monitor mechanism (30) and adjusting the rotational speed of the rotational body (10) for an {n + 1} th layer and/or a following layer, wherein n represents a positive integer of 1 or larger; and wherein the film formation method comprises setting a measurement interval t [sec] of the monitor mechanism (30) and a number of rotations A of the rotational body (10) required for one measurement in such a way as to satisfy a conditional formula: {Ra 2 × t × da} / {60 × {60 × s × A + Ra × t × s}} ≤ 0.05, wherein Ra represents the rotational speed [rpm] of the rotational body (10) for the {n + 1} th layer, da represents the desired layer thickness [nm] of the {n + 1} th layer, and s represents the forming rate [nm/sec] of the film formation mechanism (20); in a second alternative the to-be-film-formed material (50,52,54) includes a number of substrates, which number is divided into plural sections, wherein the film formation method comprises, in the step of adjusting the rotational speed of the rotational body (10), grasping the rotational speed of the rotational body (10) for an m th section of an n th layer from a result of the monitoring by the monitor mechanism (30) and adjusting the rotational speed of the rotational body (10) for an {m + 1} th section and/or a following section of the n th layer, wherein m represents a positive integer of 1 or larger, and the film formation method comprises setting a measurement interval t [sec] of the monitor mechanism (30) and a number of rotations A of the rotational body (10) required for one measurement in such a way as to satisfy a conditional formula: {Rc 2 × t × dc} / {60 × {60 × s × A + Rc × t × s}} ≤ 0.05, wherein Rc represents the rotational speed [rpm] of the rotational body (10) for the {m + 1} th section and/or the following section of the n th layer, dc represents the desired layer thickness [nm] of the n th layer of the multilayer film, and s represents the forming rate [nm/sec] of the film formation mechanism (20).
  6. The film formation method according toclaim 5, comprising adjusting a forming time or the forming rate of the film formation mechanism (20) in such a way as to make the calculated number of rotations of the rotational body (10) closer to the integer.
  7. The film formation method according to any one of claims 5 or 6, wherein the film formation apparatus (1) includes a detection mechanism (60) that detects a reference point (12) of the rotational body (10), and the film formation method comprises adjusting a rotational position of the rotational body (10) based on a result of the detection by the detection mechanism (60) such that formation of each layer starts at the reference point (12) of the rotational body (10), finishes at the reference point (12) of the rotational body (10), or starts and finishes at the reference point (12) of the rotational body (10).
  8. The film formation method according to any one of claims 5 to 7, wherein the film formation apparatus (1) includes a second film formation mechanism (70) that performs the film formation process on the to-be-film-formed material (50), and the film formation method comprises adjusting the rotational speed of the rotational body (10) in such a way as to make the calculated number of rotations of the rotational body (10) closer to the integer even in a time slot (82) for shifting from formation of the multilayer film to formation of a next multilayer film.

Description

Technological Field The present invention relates to a film formation apparatus and a film formation method, and, in particular, relates to a technology for reducing deviation from a desired thickness. Background Art Technologies for forming thin films, such as sputtering and vapor deposition, are widely known. Making film thickness(es) of a thin film(s) uniform is important to realize functions of the thin film(s). In particular, in a multilayer film composed of many layers made of metal, dielectrics and/or the like being stacked, change in layer thickness between the layers greatly affects the entire film thickness of the multilayer film. Examples of the multilayer film include optical films, such as an antireflection film. A technology for reducing difference in film thickness of a thin film is disclosed in JP 2003-321770 A. In JP 2003-321770 A, a substrate 10 is rotated such that a vapor deposition point on the substrate 10 at the start of vapor deposition is matched with a vapor deposition point on the substrate 10 at the end of vapor deposition (first embodiment), a rotational speed of the substrate 10 is set according to a target film thickness non-uniformity value a (second embodiment), or the rotational speed of the substrate 10 is set according to the target film thickness non-uniformity value a, a forming speed α and a desired film thickness d (third embodiment). US 2013/0092528 A1 discloses a film-forming device including a chamber in which a substrate is disposed, a target, disposed within the chamber, which contains a material from which a film is formed, a substrate-supporting table disposed inside the chamber, a driving unit that rotates the substrate-supporting table, a sputtering cathode that causes sputtered particles to be incident on the substrate from an oblique direction, and a control unit that controls the driving unit by setting a rotation period so that a sputtering film formation time required to form a film having a desired thickness is an integer multiple of a rotation period of the substrate-supporting table. EP 2246170 A1 discloses a seamless mold manufacturing method having the steps of forming a thermal reaction type resist layer on a sleeve-shaped mold, and exposing using a laser and developing the thermal reaction type resist layer and thereby forming a fine mold pattern while the sleeve rotates. To ensure resist layer thickness accuracy the rotation speed of the sleeve is approximately determined by the total number of rotations that is the product of the speed and the deposition time. When the total number of deposition rotations is low, due to the effect of fluctuations in the deposition rate by shutter open/close time for starting and finishing deposition, mechanical axial fluctuations of the sleeve rotation axis, temperature variations during deposition and the like, the resist thickness uniformity degrades in the circumference. To solve this problem, by increasing the total number of rotations in the deposition, the deposition rate variations are averaged, and it is possible to reduce fluctuations. Summary of the Invention Problems to be Solved by the Invention However, in forming of a multilayer film, if, like the technology of the first embodiment of JP 2003-321770 A, a forming point at the start of film formation is simply matched with a forming point at the end of film formation, forming time is extended, and deviation from a desired film thickness occurs accordingly. If, like the technologies of the second and third embodiments of JP 2003-321770A, the rotational speed of a substrate is set according to, for example, the target film thickness non-uniformity value a, although difference in layer thickness in a layer is suppressed, a micro error in layer thickness between layers occurs, and accordingly, in a multilayer film composed of such layers being stacked, deviation from a desired film thickness occurs. Hence, one of objects of the present invention is to provide a film formation apparatus and a film formation method that can reduce deviation from a desired thickness. Means for Solving the Problems In order to achieve at least one of the abovementioned objects, a film formation apparatus of the present invention comprises the features of claim 1 or claim 3 and includes inter alia: a film formation apparatus that forms a multilayer film including (n + 1) or more layers, wherein n represents a positive integer of 1 or larger, the film formation apparatus including: a rotational body that rotates while supporting a to-be-film-formed material;a film formation mechanism that performs a film formation process on the to-be-film-formed material; anda control mechanism that controls rotation of the rotational body, wherein the control mechanism calculates a number of rotations of the rotational body from a desired layer thickness of a layer of the multilayer film, a default forming rate of the film formation mechanism and a default rotational speed of the rotational