Laminate and indicator

Abstract

To provide a laminate having a color change layer configured to change a color tone thereof by detecting at least one kind selected from a group consisting of plasma, ozone, ion, ultraviolet light and radical-containing gas, and a substrate layer, the laminate with a faster color change speed at the color change layer, capable of accurately evaluating a color tone change and improving a color change sensitivity in the color change layer.SOLUTION: A laminate includes a color change layer, an underlayer and a substrate layer in this order. The color change layer includes a base material and a pigment. The pigment is a component that changes a color tone when at least one kind selected from a group consisting of plasma, ozone, ion, ultraviolet light and radical-containing gas is detected. A color difference (ΔE*ab) of the underlayer and a color tone of the color change layer after a color change is 6.5 or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a laminate and an indicator. [Background technology]

[0002] In manufacturing electronic devices, it is necessary to uniformly perform treatment with at least one selected from the group consisting of plasma, ozone, ions, ultraviolet light, and radical-containing gas (hereinafter sometimes referred to as "plasma, etc."). It is also necessary to perform treatment so that the thermal history of each electronic device is uniform. For example, it is important that treatment with plasma, etc. in the pre-process of semiconductor chip manufacturing is performed uniformly within the wafer surface, and that in-plane uniformity is maintained. If the in-plane uniformity is impaired, the performance of each semiconductor chip formed on the semiconductor wafer will vary, affecting the yield. For this reason, confirmation of the uniformity of processing by plasma or the like is essential when designing each electronic device manufacturing apparatus and when managing the manufacturing process using said apparatus. Various methods are known for evaluating the uniformity of plasma processing. Among these, methods using various indicators are known as methods for directly measuring the in-plane distribution of each treatment.

[0003] Patent Document 1 describes an indicator in which an ink containing a dye, a specific surfactant, and a nonionic surfactant is applied to a substrate. By placing this indicator in a reaction chamber or the like, it is possible to detect the end point of a treatment such as plasma. Patent Document 2 describes an indicator that includes a color-changing layer formed from ink that changes color or loses color upon reaction with plasma, etc. This indicator has the same shape as the substrate used in electronic device manufacturing equipment, and makes it possible to confirm the uniformity of treatment with plasma, etc. Patent Document 3 describes a plasma indicator in which a dye is contained in pores formed by anodization. Patent Document 4 describes a plasma indicator having a color-changing layer in the pores of a porous body, the color-changing layer containing a dye that changes color or loses color upon reaction with plasma or the like.

[0004] The indicators described in Patent Documents 1 to 4 utilize the principle that when irradiated with plasma or the like, the detecting agent decomposes and the color-changing layer changes or disappears, and analyze the in-plane distribution of irradiation with plasma or the like by measuring the color difference before and after irradiation with plasma or the like. However, if the concealing property of the color-changing layer is insufficient, the color tone of the layer below the color-changing layer may affect the color tone of the color-changing layer, making it difficult to accurately measure the color difference. On the other hand, if the color-changing layer is made thicker in order to improve the concealing property of the color-changing layer, the color-changing speed and the color-changing sensitivity may decrease. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-013982 A [Patent Document 2] International Publication No. 2015 / 025699 [Patent Document 3] International Publication No. 2018 / 128123 [Patent Document 4] JP 2020-180963 A Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a laminate having a base layer and a color-changing layer that changes color upon detecting at least one type selected from the group consisting of plasma, ozone, ions, ultraviolet light, and radical-containing gases, in which the color-changing layer changes color at a fast rate, the change in color can be accurately evaluated, and the color-changing sensitivity of the color-changing layer is improved.

[0007] As a result of investigations aimed at solving the above problems, the present inventors have found that the above problems can be solved by forming a laminate having a specific structure and using this as an indicator. Specifically, the following are included: [1] A color-changing layer, an underlayer, and a base layer are provided in this order, the color-changing layer contains a base material and a dye, the dye is a component whose color tone changes upon detection of at least one type selected from the group consisting of plasma, ozone, ions, ultraviolet light, and radical-containing gases, and the color difference (ΔE * ab) is 6.5 or less. [2] A laminate of [1], in which the constituent components of the lower layer are composed of the base material of the color-changing layer. [3] A laminate of [1] or [2], in which the thickness of the lower layer is thicker than the thickness of the color-changing layer. [4] The laminate according to any one of [1] to [3], wherein the color-changing layer is a porous layer, and the film density of the lower layer is higher than the film density of the color-changing layer. [5] The laminate according to any one of [1] to [4], wherein the color-changing layer and the lower layer are both made of a polyimide-based material. [6] A plasma indicator comprising the laminate according to any one of [1] to [5]. Effect of the Invention

[0008] The present invention provides a laminate having a base layer and a color-changing layer that changes color upon detecting at least one type selected from the group consisting of plasma, ozone, ions, ultraviolet light, and radical-containing gas, in which the color-changing layer changes color at a fast rate, the change in color can be accurately evaluated, and the color-changing sensitivity of the color-changing layer is improved. [Brief description of the drawings]

[0009] [Figure 1] 3 is a cross-sectional photograph of a laminate according to an example, which is one embodiment of the present invention. [Diagram 2] 1 is a graph showing the color difference ΔE*ab before and after discoloration of a discoloration layer versus plasma exposure time in a laminate according to an example, which is one embodiment of the present invention. [Diagram 3] 1 is a graph showing the change in a*b* coordinates (color change) in the L*a*b* color space of a color-changing layer versus plasma exposure time in a laminate according to an example, which is one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Laminate] The laminate of the present invention comprises a color-change layer, an underlayer, and a base layer in this order, the color-change layer contains a base material and a dye, the dye being a component whose color tone changes upon detection of at least one type of light selected from the group consisting of plasma, ozone, ions, ultraviolet light, and radical-containing gases, and a color difference (ΔE * ab) is 6.5 or less. In this specification, the terms plasma, ozone, ions, ultraviolet rays and radical-containing gas are defined as follows.

[0011] <Plasma> The plasma refers to plasma generated by applying an AC voltage, a DC voltage, a pulse voltage, high frequency, microwaves, or the like using a plasma generating gas, and includes both low-pressure plasma and atmospheric pressure plasma. As the plasma generating gas, for example, at least one gas selected from the group consisting of oxygen, nitrogen, hydrogen, fluorine, chlorine, helium, neon, argon, silane, ammonia, sulfur bromide, water vapor, nitrous oxide, tetraethoxysilane, carbon tetrafluoride, trifluoromethane, carbon tetrachloride, silicon tetrachloride, sulfur hexafluoride, titanium tetrachloride, dichlorosilane, trimethylgallium, trimethylindium, trimethylaluminum, air, and carbon dioxide can be used. Examples of the plasma include plasma generated in a plasma processing apparatus (an apparatus that performs plasma processing by applying an AC voltage, a DC voltage, a pulse voltage, a high frequency wave, a microwave, or the like in an atmosphere containing a gas for generating plasma) used in a film formation process, an etching process, an ashing process, an impurity addition process, a cleaning process, and the like during the manufacture of an electronic device.

[0012] <Ozone> Examples of ozone include ozone generated when oxygen is exposed to ultraviolet light, ozone generated by discharging in an oxygen-containing gas such as dry air or in oxygen gas, ozone generated by electrolysis of dilute sulfuric acid, etc. For example, ozone may be ozone generated in an ozone treatment device used in a film formation process, an ashing process, a cleaning process, etc. during the manufacture of electronic devices, or ozone generated during the generation of photochemical smog. <Aeon> Examples of ions include those generated by applying high-frequency power to gases such as argon, methane, acetylene, etc. For example, ions may be those used in sputtering, which is performed by accelerating ionized argon in an electric field in a vacuum and irradiating and colliding it with a metal surface or the like to remove surface atoms by utilizing the property of hardly causing a chemical reaction, ion beam etching, doping, etc.

[0013] <Ultraviolet rays> Ultraviolet rays refer to electromagnetic waves with wavelengths of about 1 to 400 nm, and include near ultraviolet rays, far ultraviolet rays, vacuum ultraviolet rays, and extreme ultraviolet rays. For example, ultraviolet rays can be generated from ultraviolet irradiation devices including mercury lamps and LEDs, or can be obtained from ultraviolet treatment devices used in photolithography, ashing, cleaning, and other processes during the manufacture of electronic devices.

[0014] <Radical-containing gas> The radical-containing gas is, for example, hydrogen gas passed through a Ta thin tube heated to 2100 K by electron beam bombardment, and the degree of vacuum is set to 1.0×10 -4 Torr~1.0×10 -6 Torr. Furthermore, for example, the radical-containing gas can be obtained by a radical-containing gas treatment apparatus used in a film-forming process, an etching process, an ashing process, a cleaning process, or the like during the manufacture of electronic devices.

[0015] <Discolored layer> The color-changing layer contains a base material and a dye. The color change of the color-changing layer occurs when the dye comes into contact with plasma or the like, causing one or more color changes, such as discoloration, decolorization, or color development. Here, the plasma or the like is at least one selected from the group consisting of plasma, ozone, ions, ultraviolet rays, and radical-containing gases, as described above. In the color-changing layer of the present invention, the detecting agent is uniformly present within the surface of the color-changing layer.

[0016] (Base material) The base material is not particularly limited as long as it can hold the detecting agent such as plasma and can form a discoloration layer. The base material is at least one selected from the group consisting of organic materials, inorganic materials, and organic-inorganic composite materials. By using the base material, it is possible to measure the color change of the detecting agent over time according to the penetration degree of the plasma, etc., and the color change proportional to the amount or strength of exposure to the plasma, etc. The color tone of the base material may be any color tone that allows the change in color tone of the dye to be grasped, and is preferably transparent, colored transparent, white, or pale color.

[0017] The organic material may be at least one selected from the group consisting of resin, nonwoven fabric, knitted fabric, woven fabric, paper, activated carbon, fullerene, carbon nanotube, and the like. The resin is not particularly limited. For example, at least one selected from the group consisting of polyimide resin, polyamideimide resin, polybenzimidazole resin, polyamide resin, polyolefin resin, polyurethane resin, melamine resin, polyester resin, polycarbonate resin, etc. can be mentioned. In particular, when polyamideimide resin, polyimide resin, polybenzimidazole resin, or polyamide resin is used as the base material, a laminate with excellent heat resistance is obtained, so that an indicator that can be used under high temperature conditions and has strong resistance to plasma treatment can be constructed. Examples of inorganic materials include one or more materials selected from the group consisting of metals, silica-based materials, alumina-based materials, zeolite-based materials, silicate-based materials, glass-based materials, ceramic-based materials, mesoporous materials, natural ores, metal oxides, and metal hydroxides. In the present invention, when the content of each metal atom in the laminate is set to less than 5.0 ppm by mass, it is preferable to use an organic material, particularly a resin, as the base material constituting the color-change layer. In order to prevent contamination of the inside of electronic device manufacturing equipment with metal atoms, it is preferable to use an organic material, particularly a resin, as the base material constituting the color-change layer.

[0018] The form of the base material of the present invention is not particularly limited, and examples thereof include a porous body having an internal space communicating with the openings on the surface, a binder in which the detecting agent is dissolved and uniformly contained, and a binder in which the detecting agent is uniformly dispersed. When the base material is a porous body, the internal space of the porous body communicates with the surface openings, and the internal space contains at least one type of detecting agent, forming a discoloration layer. In this case, plasma or the like can easily come into contact with the detecting agent, so that the discoloration rate of the discoloration layer can be increased, the change in color tone can be accurately evaluated, and the discoloration sensitivity of the discoloration layer can be improved. When the base material is a binder, at least one type of binder and at least one type of detecting agent are uniformly mixed to form a non-porous discoloration layer made of a composition. In this case, deterioration of the detecting agent over time can be prevented.

[0019] In the present invention, by using a porous body as the base material, the color change speed of the color change layer can be increased, the change in color tone can be accurately evaluated, and the color change sensitivity of the color change layer can be improved. As the base material, for example, (i) a porous body having an internal space communicating with the openings on the surface, (ii) at least one of holes, recesses, protrusions, and cracks is provided to form an internal space corresponding to the openings on the surface, and (iii) a composition having a porous substance disposed on the surface, etc. can be used. Among these, (i) a porous body having an internal space communicating with the openings on the surface is preferably used.

[0020] The materials constituting the base material may contain components such as an extender, if necessary. In the present invention, when the content of each metal atom in the laminate is less than 5.0 ppm by mass and / or the content of each halogen atom is less than 30 ppm by mass, it is preferable to use a base material that does not contain metal atoms and / or halogen atoms. When the content of each metal atom in the laminate is less than 5.0 ppm by mass and / or the content of each halogen atom is less than 30 ppm by mass, it is preferable to use an organic porous body, particularly a resin porous body, as the structure constituting the color-changing layer, which can reduce contamination of the inside of an electronic device manufacturing apparatus by metal atoms and / or halogen atoms.

[0021] (Detection agent) The detecting agent contains at least one dye that changes color upon detecting plasma etc. The detecting agent may contain other components in addition to the dye as necessary. In the present invention, the detecting agent is preferably composed of a compound that does not contain metal atoms, particularly a dye that does not contain atoms other than carbon, hydrogen, oxygen, and nitrogen. In addition, it is preferable to prevent impurities such as metal atoms and halogen atoms from being mixed into the detecting agent by thoroughly purifying the components thereof and not using metal tools during preparation. This makes it possible to make the content of each metal atom in the laminate less than 5.0 ppm by mass and / or the content of each halogen atom in the laminate less than 30 ppm by mass, and when the laminate is used as an indicator for detecting plasma or the like, contamination in an electronic device manufacturing apparatus, particularly contamination by metal atoms and halogen atoms, can be effectively prevented. The detecting agent may contain components other than the dye, within a range that does not impair the effect of the color change caused by the dye, for the purpose of adjusting the sensitivity, improving the visibility of the color difference before and after detection, etc. Examples of such components include at least one selected from the group consisting of dyes that do not function as dyes (those that do not change in color when exposed to a detection target), resins and / or resin precursors, surfactants, fillers, color change retarders, color change promoters, solvents, leveling agents, antifoaming agents, and other additives.

[0022] {pigment} The dye that changes color upon detecting plasma or the like is not particularly limited as long as it exhibits a behavior in which the color tone changes when exposed to plasma or the like. For example, among dyes known as colorants, preferably dyes and pigments, at least one selected from the group consisting of dyes that change color upon detecting plasma or the like is included. For example, it is preferable to use at least one selected from the group consisting of anthraquinone dyes, perylene dyes, methine dyes, azo dyes (monoazo dyes, diazo dyes, triazo dyes, polyazo dyes, azoic dyes (diazo components), azoic dyes (coupling components), etc.), phthalocyanine dyes, triarylmethane dyes, xanthene dyes, oxazine dyes, indanthrene dyes, food dyes, and perinone dyes. Preferably, the dye is at least one selected from the group consisting of anthraquinone-based dyes, perylene-based dyes, methine-based dyes, azo-based dyes, phthalocyanine-based dyes, triarylmethane-based dyes, xanthene-based dyes, indanthrene-based dyes, and edible dyes, and particularly preferably, the dye is at least one selected from the group consisting of anthraquinone-based dyes, perylene-based dyes, methine-based dyes, indanthrene-based dyes, and azo-based dyes.

[0023] Specific examples of these dyes include CIAzoic Coupling Component 3, 16, CIBasic Green 4, CIMordant Red 27, CISolvent Black 3, CISolvent Blue 35, CISolvent Red 18, 24, 27, 49, 52, CISolvent Violet 14, CISolvent Yellow 29, CIVat Black 8, 9, 25, 27, 29, CIVat Brown 1, 3, 25, 44, CIVat Green 8, CIVat Orange 13, 15, CIVat Red 10, 13, 15, CIVat Yellow 10, 20, Lumogen F IR 788, Lumogen F Orange 240, Lumogen F Pink 285, Lumogen F Red 300, 305, 339, Lumogen F Violet 570, Lumogen F Yellow 083,170, Iketon Violet extra, Oil Peacock Blue, and Oil Brown BG extra.

[0024] In the present invention, the color change sensitivity of the detecting agent and the color development and color change of the color-changing layer can be controlled by selecting the type of dye (e.g., molecular structure), using a mixture of multiple dyes, adjusting the dye content, etc. The content of the detecting agent in the color-changing layer may be appropriately adjusted depending on the type of detecting agent, color change sensitivity, product form, characteristics of the base material, and the like. For example, the detection agent in the color-changing layer is, for example, 0.01 mass % or more, preferably 0.05 mass % or more, more preferably 0.10 mass % or more, and for example, 20.0 mass % or less, preferably 10.0 mass % or less, more preferably 1.0 mass % or less, and even more preferably 0.7 mass % or less. If the color-changing layer contains a large amount of detection agent, the color-changing sensitivity tends to decrease. If the amount of detection agent is too small, the color-changing sensitivity also tends to decrease.

[0025] (Thickness of discoloration layer) The film thickness (thickness) of the color-changing layer is not particularly limited as long as it exhibits a detection function, and can be appropriately optimized according to the application, desired characteristics, etc. In terms of the color-changing layer's color-changing speed, color tone change evaluation accuracy, and color-changing sensitivity, it is, for example, less than 10 μm, preferably 9.5 μm, more preferably 9 μm or less, for example, 0.5 μm or more, preferably 1 μm or more. If the color-changing layer has a film thickness of 10 μm or more, the color-changing speed is slow, and when the processing time of plasma or the like is short or the output of plasma or the like is weak, the accuracy of the color tone change evaluation and the color-changing sensitivity may be insufficient. In addition, if the film thickness is less than 0.5 μm, the color-changing layer is insufficient in coloring, the color-changing range is narrow, and the accuracy of the color tone change evaluation may be insufficient.

[0026] (Film density of discoloration layer) The film density of the color-changing layer is not particularly limited as long as it does not impair the detection function, and can be appropriately optimized according to the application, desired characteristics, etc. For example, when the color-changing layer is a non-porous layer, it is the film density of the base material. When the color-changing layer is a porous layer, the film density is 75.0% or less, preferably 35.0% or less, more preferably 30.0% or less, more preferably 25.0% or less, and preferably 15.0% or more, based on the film density of the base material when the color-changing layer is a non-porous layer being 100%. If it is less than 15.0%, it is difficult to form the color-changing layer, and the film strength of the color-changing layer is insufficient. If it exceeds 75.0%, the penetration of plasma into the color-changing layer is hindered, the decomposition of the detection agent is not performed sufficiently, and the color-changing sensitivity of the color-changing layer is reduced. In the present invention, by forming the color-changing layer as a porous layer, it is possible to satisfy the color-changing speed of the color-changing layer, the accuracy of the color tone change evaluation, and the color-changing sensitivity.

[0027] The film density can be set to any value by adjusting the porosity of the base material constituting the color-changing layer. Examples of methods for adjusting the porosity of the base material constituting the color-changing layer include (1) a method for adjusting the resin constituting the base material, the type and amount of a good solvent for the resin, and the type and amount of a poor solvent for the resin, and (2) a method for adjusting the resin constituting the base material constituting the color-changing layer and the amount of a foaming agent, etc. In the present invention, a good solvent for a resin is a solvent that dissolves 0.1 g or more of the resin in 100 g of the solvent at 25° C. A poor solvent for a resin is a solvent that dissolves less than 0.1 g of the resin in 100 g of the solvent at 25° C.

[0028] In the present invention, it is preferable to adjust the porosity of the base material by the method (1). In this case, the resin constituting the base material is preferably a polyimide resin, a polyamideimide resin, a polybenzimidazole resin, etc., the good solvent is preferably a nitrogen-containing polar solvent such as an amide solvent or a urea solvent, and the poor solvent is preferably an ether solvent, a hydrocarbon solvent, an ester solvent, etc. Examples of the amide solvent include N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide (DMAc), etc. Examples of the urea solvent include tetramethylurea, dimethylethyleneurea, etc. Examples of ether solvents include diglyme, triglyme, tetraethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tripropylene glycol dimethyl ether, dipropylene glycol dimethyl ether, tetrahydrofuran, and dioxane. Examples of hydrocarbon solvents include n-hexane, cyclohexane, benzene, toluene, xylene, and petroleum ether. Examples of ester solvents include ethyl carbitol acetate, butyl carbitol acetate, dimethyl succinate, diethyl succinate, dimethyl glutarate, diethyl glutarate, dimethyl adipate, and diethyl adipate.

[0029] In the present invention, when the total amount of the resin, the good solvent, and the poor solvent is taken as 100 mass %, the amounts of the resin, the good solvent, and the poor solvent used are preferably as follows, respectively. Resin: for example, 7.0% by mass or more, preferably 8.0% by mass or more, and for example, 15.0% by mass or less, preferably 11.0% by mass or less Good solvent: for example, 10.0% by mass or more, preferably 15.0% by mass or more, and for example, 50.0% by mass or less, preferably 40.0% by mass or less Poor solvent: for example, 35.0% by mass or more, preferably 40.0% by mass or more, and for example, 80.0% by mass or less, preferably 70.0% by mass or less If the amount of the resin exceeds 15.0% by mass, it is difficult to adjust the porosity and the color change range may be narrowed, whereas if the amount of the resin is less than 7.0% by mass, the porous film may not be formed and the color change sensitivity may be deteriorated. If the amount of the good solvent exceeds 50.0% by mass, it may be impossible to form a porous film, and if the amount of the good solvent is less than 10.0% by mass, unevenness may occur and phase separation may occur. If the amount of the poor solvent exceeds 80.0% by mass, unevenness may occur and phase separation may occur, whereas if the amount of the poor solvent is less than 35.0% by mass, a porous membrane may not be formed.

[0030] In the present invention, a varnish containing a resin and an organic solvent may be used, and a good solvent and a poor solvent may be mixed with the resin varnish. As the resin varnish, a varnish having a resin content of 10 to 20 mass%, preferably 10 to 15 mass%, may be used. In this case, when the total amount of the resin varnish, the good solvent, and the poor solvent is taken as 100 mass%, it is preferable that the amounts of the resin, the good solvent, and the poor solvent are respectively as follows. Resin varnish: for example, 60% by mass or more, preferably 70% by mass or more, and for example, 90% by mass or less, preferably 80% by mass or less Good solvent: for example, 1% by mass or more, preferably 10% by mass or more, and for example, 20% by mass or less, preferably 15% by mass or less Poor solvent: for example, 1% by mass or more, preferably 10% by mass or more, for example, 20% by mass or less, preferably 15% by mass or less If the amount of the resin exceeds 90% by mass, the discoloration range may be narrowed, whereas if the amount of the resin is less than 60% by mass, the porous film may not be formed and the discoloration sensitivity may be deteriorated. If the amount of the good solvent exceeds 20% by mass, it may be impossible to form a porous film, and if the amount of the good solvent is less than 1% by mass, unevenness may occur and phase separation may occur. If the amount of the poor solvent exceeds 20% by mass, unevenness may occur and phase separation may occur, whereas if the amount of the poor solvent is less than 1% by mass, a porous membrane may not be formed.

[0031] <lower layer> The lower layer is formed between the color-changing layer and the base layer, and is not particularly limited as long as the color difference (ΔE*ab) between the color tone of the lower layer and the color tone of the color-changing layer after discoloration is 6.5 or less. By providing such an underlayer, it is possible to prevent the color tone of the base layer from affecting the color tone of the color-changing layer and the observation of the discoloration of the color-changing layer. As a result, the color-changing layer can be made to change at a high speed, the change in color tone can be accurately evaluated, and the color-changing sensitivity of the color-changing layer can be improved. In the present invention, the main cause of the color change is discoloration due to decomposition of the dye in the color-changing layer. Note that, depending on the plasma conditions, discoloration may occur due to etching. Even in such a case, the present invention can accurately evaluate the color change.

[0032] (Color difference ΔE between the lower layer and the discolored layer after discoloration * ab) Color difference ΔE between the lower layer and the discolored layer after discoloration * ab is 6.5 or less, preferably less than 3.0, more preferably less than 1.6, and even more preferably less than 0.8. Color difference ΔE * When ab is 6.5 or less, the colors can be treated as the same color at the impression level, and this is the allowable color difference range in which the colors can generally be treated as the same color tone in color management. * It is preferable to set ab to less than 3.0 (a color difference that is barely noticeable in a color comparison and is generally considered to be the same color, and is the acceptable color difference range in which the standard color sample and the sample color are judged to be the same color tone when visually judged). By setting the color difference to 6.5 or less, the color change speed is fast, the change in color tone can be accurately evaluated, and the color change sensitivity of the color change layer is improved. Color difference ΔE * The adjustment of ab can be performed by adding various dyes to the lower layer and / or the color-changing layer, etc. Also, it can be performed by using the same materials for the lower layer and the color-changing layer that does not contain a dye.

[0033] Color difference ΔE * ab is L * a * b * This is the color difference in the color space. * , a * and b * and L of the discolored layer after plasma treatment * , a * and b * Measure each with a colorimeter and calculate the difference ΔL * , Δa * , Δb * The following formula is calculated: ΔE * ab = [(ΔL * ) 2 +(Δa * ) 2 +(Δb * ) 2 ] 1 / 2 is required from.

[0034] (Constituent material of lower layer) The material for the lower layer is not particularly limited as long as the color difference (ΔE*ab) between the color tone of the lower layer and the color tone of the color-changing layer after the color change is 6.5 or less. For example, the materials listed as the base material for the color-changing layer can be used. For example, if it is made of the same components as the base material that makes up the discoloration layer, the color tone of the lower layer will be similar to the color tone of the discoloration layer after discoloration, making it possible to more accurately evaluate the discoloration of the discoloration layer. Furthermore, even if the components of the concealing layer are different from the base material constituting the color-changing layer, it is advantageous to consider the color tone and make it similar to the color tone of the color-changing layer after discoloration. Furthermore, by making the lower layer a lower layer having a primer function, the adhesion between the base layer and the color-changing layer can be improved. In the present invention, it is simple and preferable that the constituent components of the lower layer are composed of the same material as the base material of the color-changing layer (the constituent materials of the lower layer and the color-changing layer not containing a pigment are the same). In the present invention, it is preferable that both the color-changing layer and the lower layer are made of a polyimide-based material.

[0035] (Relationship between the thickness of the lower layer and the discolored layer) The thickness of the lower layer is preferably thicker than the thickness of the color-changing layer. This can prevent the color tone of the base layer from affecting the color tone of the color-changing layer and the observation of the color change of the color-changing layer. The thickness of the lower layer is not particularly limited, but is, for example, 1.1 times or more, preferably 1.2 times or more, more preferably 1.5 times or more, and 10.0 times or less, preferably 5.0 times or less, of the thickness of the color-changing layer.

[0036] (Relationship between film density in the lower layer and discolored layer) When the color-changing layer is a porous layer, the film density of the lower layer is preferably higher than that of the color-changing layer. This can prevent the color tone of the base layer from affecting the color tone of the color-changing layer and the observation of the color change of the color-changing layer. The film density of the lower layer is not particularly limited, but is, for example, 1.20 times or more, preferably 1.30 times or more, more preferably 1.40 times or more, and 100.0 times or less, preferably 80.0 times or less, of the film density of the color-changing layer.

[0037] <Base material layer> The substrate layer is not particularly limited as long as it can support the color-changing layer. At least one material selected from the group consisting of inorganic materials, organic materials, and composites thereof can be used. The thickness of the base layer is not particularly limited as long as it can reliably support the color-changing layer, and is, for example, 0.01 mm or more, preferably 0.1 mm or more, and, for example, 10 mm or less, preferably 1 mm or less.

[0038] The inorganic material constituting the substrate layer may be, for example, at least one material selected from the group consisting of metals or alloys, semiconductor materials, ceramics, glass, quartz, sapphire, and concrete. The organic material constituting the base layer may be, for example, at least one selected from the group consisting of resin, paper, fibers (nonwoven fabric, knitted fabric, woven fabric, other fiber sheets), leather, and the like. Of these, it is preferable to use at least one material selected from the group consisting of semiconductor materials, glass, sapphire, resin, and paper as the base material layer.

[0039] Examples of the semiconductor material include, but are not limited to, at least one selected from the group consisting of metal oxides and metal oxynitrides such as silicon (Si), germanium (Ge), tellurium (Te), zinc oxide (ZnO), gallium arsenide (GaAs), gallium nitride (GaN), gallium oxide (Ga2O3), aluminum nitride (AlN), indium nitride (InN), silicon carbide (SiC), aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), and indium aluminum gallium nitride (InAlGaN). Examples of the resin include at least one selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polyethylene-based resins, polypropylene-based resins, polynorbornene-based resins, polyamide-based resins, polyamideimide-based resins, polyimide-based resins, polycarbonate-based resins, and acrylic-based resins.

[0040] When the laminate is used as an indicator in a manufacturing device for each product, examples of materials constituting the base layer include the following. Indicators for semiconductor manufacturing equipment: silicon, gallium arsenide, silicon carbide, etc. Indicators for LED manufacturing equipment: Sapphire, Gallium Nitride, Gallium Arsenide, etc. Indicators for semiconductor laser manufacturing equipment: Gallium arsenide, gallium nitride, sapphire, etc. Indicators for power device manufacturing equipment: silicon carbide, gallium nitride, silicon, etc. Indicators for solar cell manufacturing equipment: silicon, glass, germanium, etc. Indicators for LCD manufacturing equipment: silicon, glass, germanium, etc. Indicators for organic EL display manufacturing equipment: glass, etc. General-purpose / simple indicators: resin, paper, glass, etc.

[0041] <Layer configuration> The laminate of the present invention may have other layers in addition to the color-changing layer, the lower layer, and the base layer. The other layers are the color-changing layer, the lower layer, and the base layer in this order, and can be provided at any position as long as they do not interfere with the detection of plasma or the like in the color-changing layer. The color-changing layer, the underlayer, and the other layers may each be formed as one layer, or as multiple layers. Also, the same layers may be adjacent to each other. In this case, the same layers may have the same composition or different compositions. The color-changing layer, the underlayer, and other layers may be formed on the entire surface of the substrate layer or each layer, or may be formed partially. In these cases, the color-changing layer and other layers can be formed so that at least one color-changing layer is partially or entirely exposed to plasma or the like, in order to ensure a color tone change of the color-changing layer in particular.

[0042] The laminate of the present invention may be formed by combining the color-changing layer, the underlayer, and other layers in any combination, as long as the completion of each of the above-mentioned treatments and the in-plane uniformity can be confirmed. The color-changing layer may not overlap the other layers, or may overlap the other layers. The laminate of the present invention may be configured such that at least one of letters, designs, and symbols appears due to the change in color of the color-changing layer, in order to notify the user that the color tone of the color-changing layer has changed due to plasma, etc. The letters, designs, and symbols include all information that notifies the user of a color change, and these letters, etc. can be designed appropriately depending on the purpose of use, etc.

[0043] <Shape> The laminate of the present invention may have any shape depending on the application. For example, the laminate can be made to have the same or nearly the same shape as a substrate used in an electronic device manufacturing apparatus and used as a so-called dummy substrate, making it possible to easily detect whether the above-mentioned processing is being performed uniformly over the entire substrate.

[0044] <Content of each metal atom in the laminate> The content of each metal atom in the laminate is preferably less than 5.0 ppm by mass, more preferably less than 1.0 ppm by mass, even more preferably less than 0.5 ppm by mass, even more preferably less than 0.1 ppm by mass, most preferably less than 1.0 ppt by mass, and even more preferably less than 0.5 ppt by mass. Here, "metal atom" means an atom other than hydrogen, carbon, nitrogen, oxygen, silicon, fluorine, chlorine, bromine, iodine and rare gases. In order to make the content of each metal atom in the laminate less than 5.0 ppm by mass, all materials contained in the laminate are made to be free of metal atoms. In addition, all components related to the laminate (including solvents, etc.) are made to be free of metal atoms, and metal atom-containing substances contained as impurities are removed by purification. Furthermore, it is preferable not to use tools, etc. that may cause contamination of metal atoms in the manufacturing process. In the present invention, the content of each metal atom in all layers, including the discoloration layer, lower layer, and base layer, is measured by ICP-MS (Inductively Coupled Plasma Mass Spectrometry) or the like, and if each is less than 5.0 ppm by mass, the content of each metal atom in the laminate is determined to be less than 5.0 ppm by mass. Also, an indicator including the laminate of the present invention is introduced into a treatment device together with a material to be treated, and a treatment such as plasma treatment is carried out. After that, each metal atom on the surface of the material to be treated introduced into the treatment device is recovered with hydrofluoric acid or the like, and the content of each metal atom is measured by ICP-MS or the like. If each is less than 5.0 ppm by mass, each metal atom in the laminate is deemed to be less than 5.0 ppm by mass. By making the content of each metal atom in the laminate less than 5.0 ppm by mass, when the laminate is used as an indicator in an electronic device manufacturing equipment, it is possible to prevent contamination of the treated object and the inside of the manufacturing equipment with metal atoms. This makes it possible to obtain an indicator that can be used in the manufacturing process of semiconductor electronic devices (particularly the etching process in the first half of the process) where the presence of metal atoms is particularly undesirable.

[0045] <Content of each halogen atom in the laminate> The content of each halogen atom in the laminate is preferably less than 30 ppm by mass, more preferably less than 5 ppm by mass, even more preferably less than 1 ppm by mass, still more preferably less than 0.5 ppm by mass, and most preferably less than 1.0 ppt by mass. In order to make the content of each halogen atom in the laminate less than 30 ppm by mass, it is preferable that all materials contained in the laminate are composed of materials that do not contain halogen atoms. It is also preferable to use all components (including solvents, etc.) related to the laminate that do not contain halogen atoms and to remove halogen-atom-containing substances contained as impurities by purification. Furthermore, it is preferable to use a method, etc. that does not use tools, etc. that may cause contamination of halogen atoms in the manufacturing process. In the present invention, the content of each halogen atom in all layers, including the color-changing layer, lower layer, and base layer, is measured by combustion ion chromatography, ICP-MS (inductively coupled plasma mass spectrometry), or the like, and if each is less than 30 ppm by mass, the content of each halogen atom in the laminate is determined to be less than 30 ppm by mass. Also, an indicator including the laminate of the present invention is introduced into a treatment device together with a material to be treated, and a treatment such as plasma treatment is carried out. Thereafter, halogen atoms present on the surface of the material to be treated introduced into the treatment device are collected and the content of each halogen atom is measured by combustion ion chromatography, ICP-MS, or the like, and if each is less than 30 ppm by mass, the content of each halogen atom in the laminate is determined to be less than 30 ppm by mass. By making the content of each halogen atom in the laminate less than 30 ppm by mass, when the laminate is used as an indicator in an electronic device manufacturing equipment, it is possible to prevent contamination of the treated material and the inside of the manufacturing equipment with halogen atoms. This makes it possible to obtain an indicator that can be used in the manufacturing process of semiconductor electronic devices (particularly the etching process in the first half of the process) where the presence of halogen atoms is particularly undesirable.

[0046] <Method of manufacturing laminate> The method for producing the laminate is not particularly limited, and examples thereof include the following methods (1) to (5). (1) A method in which a lower layer is provided on a substrate layer, a color-changing layer-forming material containing a base material and a detecting agent is applied on the lower layer, and the color-changing layer is formed by drying and heating to form a laminate. (2) A method in which a lower layer is provided on a substrate layer, and a discoloration layer-forming material containing a base material, a detection agent, a poor solvent for the base material, and a good solvent for the base material is applied on the lower layer, and then dried and heated to form a porous discoloration layer, resulting in a laminate. (3) A method in which a lower layer is provided on a substrate layer, and a base material having an internal space communicating with the openings on the surface is provided on the lower layer, and then a detecting agent or a detecting agent solution is applied, impregnated or sprayed, etc., to retain the detecting agent in the internal space, thereby forming a laminate. (4) A method in which a composition containing a base material, a component that forms an internal space in the base material that communicates with the openings in the surface, and the detecting agent is provided on a substrate layer, and then a treatment is performed to form an internal space in the base material that communicates with the openings in the surface. (5) A method in which a detecting agent or a detecting agent solution is applied, impregnated or sprayed onto a base material having an internal space communicating with the openings on the surface, thereby retaining the detecting agent within the internal space, and then fixing the detecting agent onto a lower layer provided on the base layer. (5) A method in which a discoloration layer-forming material containing a base material, a detection agent, a poor solvent for the base material, and a good solvent for the base material is applied, and then dried and heated to form a porous discoloration layer, which is then fixed on top of a substrate layer. In the present invention, from the viewpoints of ease of production of the laminate and prevention of impurities from being mixed into the laminate, methods (1) to (3) are preferred, method (1) or (2) is more preferred, and method (1) is even more preferred.

[0047] When the laminate of the present invention has a polyimide resin lower layer on a base layer, and a color-changing layer containing a polyimide resin and a detecting agent on the lower layer, the color-changing layer is preferably produced, for example, by the following methods a to c. A method in which a mixture of polyimide (PI) or its precursor + good solvent for PI or its precursor + poor solvent for PI or its precursor + dye is prepared, and then coated and dried to form a porous color-changing layer. b: A method in which a mixture of polyimide (PI) or its precursor + organic solvent (a good solvent for PI or its precursor) + dye is prepared, and this mixture is coated and dried to form a non-porous color-changing layer. c: A method in which a porous polyimide (PI) membrane is formed, then impregnated with a dye solution and dried to form a porous discoloration layer.

[0048] In addition, when mixing, dissolving or dispersing the components in forming the discoloration layer, etc., a known stirrer can be used as necessary. In this case, it is preferable to prevent contaminating components caused by the stirrer from being mixed. When mixing, dissolving or dispersing, a known method can be used. For example, a method of adding the dye to the solvent, a method of adding the solvent to the dye, a method of adding each component constituting the detecting agent to the solvent in order, etc. can be used. When the dye is retained in the internal space, the solvent can be removed by a known means such as drying, if necessary. When providing a base material on a substrate layer, the substrate layer may be subjected to a surface treatment as necessary to improve adhesion. The surface treatment may be at least one selected from the group consisting of well-known methods such as primer treatment, chemical conversion treatment, plasma treatment, corona treatment, flame treatment, and sandblasting treatment.

[0049] <Applications of laminates> The laminate of the present invention can be used not only to detect plasma, etc., by measuring the color difference based on the color of the discoloration layer before treatment, but also as an indicator to detect the uniformity of treatment such as plasma, and a temperature indicator to easily and relatively detect the temperature distribution on the surface of the treated object. For example, the laminate can be used as an indicator for use in an apparatus for manufacturing electronic devices such as semiconductors, LEDs, semiconductor lasers, power devices, solar cells, liquid crystal displays, organic EL displays, MEMS, etc. Also, the laminate can be used as a general-purpose / simple indicator for detecting plasma, etc.

[0050] When using the indicator, the indicator of the present invention may be placed at a location where a substrate is placed in each electronic device manufacturing apparatus where the above-mentioned processes are carried out during the manufacture of electronic devices. For example, the wafer may be placed horizontally (horizontally) on a wafer stage, heater, vacuum chuck table, etc., or may be placed vertically (vertically) using a wafer boat, etc. When the indicator of the present invention has the same shape as a substrate used in manufacturing an electronic device, it can be handled and installed in the same manner as a substrate. In such a case, an indicator placed within the apparatus changes color when exposed to the treatment, and the in-plane uniformity of the treatment can be easily detected. EXAMPLES

[0051] The laminate and indicator of the present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to these examples. In addition, unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass".

[0052] [Laminate manufacturing] The silicon wafer was immersed in an alkaline cleaning solution consisting of ammonia water, hydrogen peroxide water, and pure water for 5 minutes to make the surface hydrophilic, and then washed with pure water to condition the substrate. A polyimide precursor varnish for forming an underlayer, which contains a polyimide precursor (polyamic acid), an amide-based solvent, and an ether-based solvent, is applied onto the substrate prepared above, prebaked at 110 to 170°C, and then postbaked at 250 to 350°C to obtain a dry film thickness of 21.0 μm and a dry film density of 0.45 g / cm. 3 A lower layer of was formed on the substrate. A polyimide precursor varnish for forming an upper layer, which contains a polyimide precursor (polyamic acid), an amide-based solvent, an ether-based solvent, and a perylene-based red dye, is applied onto the lower layer, prebaked at 110 to 170°C, and then postbaked at 250 to 350°C to form a film having a dry thickness of 7.0 μm and a dry film density of 0.30 g / cm. 3 A color-changing layer of the above formula was formed on the lower layer to obtain a laminate.

[0053] [Color change of laminated body due to plasma] The resulting laminate was subjected to a plasma treatment under the following conditions. <Plasma treatment conditions> Plasma method: Capacitively coupled (CCP) Interelectrode distance: 40mm Plasma gas: 1:1 mixture of O2 and CF4 Gas flow rate: O2 = 75sccm, CF4 = 75sccm Processing pressure: 20Pa Power: 50W

[0054] Color difference ΔE before and after plasma exposure for laminates * The graphs ab are shown in Figure 2. As shown in Figure 2, in the laminate of the present invention, only the color change of the color-changing layer can be accurately observed. In addition, the relationship between the plasma irradiation time and the L * a * b * In color space, L * a * b * The change in coordinates (color change) is shown in Table 1. * b * The change in coordinates (change in color tone) is shown in Figure 3. As shown in Table 1 and Figure 3, in the laminate of the present invention, the color-changing layer changes from the initial color (reddish color) to a color that is almost the same as the color of the lower layer (yellowish color) as the plasma irradiation time elapses, and the L * , a * and b * When the values ​​become almost the same, the discoloration reaches saturation. This makes it easy to determine the end point of the discoloration, and allows accurate observation of only the color tone change of the discolored layer.

[0055] [Table 1]

Claims

1. A color-changing layer, a lower layer, and a base layer are provided in this order, the color-changing layer contains a resin and a dye, the dye being a component that changes color when it detects at least one type of light selected from the group consisting of plasma, ozone, ions, ultraviolet light, and a radical-containing gas; Color difference ΔE between the lower layer and the color-changing layer after discoloration ＊ ab is 3.0 or less; Laminate.

2. 2. The laminate according to claim 1, wherein the constituent components of the lower layer are composed of a resin of the color-changing layer.

3. 3. The laminate according to claim 1, wherein the lower layer has a thickness greater than that of the color-changing layer.

4. 4. The laminate according to claim 1, wherein the color-changing layer is a porous layer, and the film density of the lower layer is higher than the film density of the color-changing layer.

5. The laminate according to any one of claims 1 to 4, wherein the color-changing layer and the lower layer are both made of a polyimide-based material.

6. A plasma indicator comprising the laminate according to any one of claims 1 to 5.

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