JP5664999B2 - Method for forming organic-inorganic composite film and developer for organic-inorganic composite film - Google Patents

Description

  The present invention relates to silicon, metal, silicon or metal oxide, silicon or metal nitride, silicon or metal carbide used in optical films, display elements, touch panels, electronic paper, various sensors and the like, and at least of these. The present invention relates to a method for producing a functional coating film containing at least one kind of inorganic fine particles selected from the group consisting of two kinds of composites by a photolithography method and a developer used at that time.

  In devices using light, such as touch panels, display elements, and various sensors, device performance is improved by laminating a wide variety of thin films with highly controlled optical characteristics. At this time, the required characteristics can be obtained by allowing these thin films to exist only at desired sites. For this purpose, a photolithography method is generally used. The thin film used here is made of various organic and inorganic films. In particular, an organic-inorganic composite film in which an inorganic material such as a metal or its oxide is introduced into the organic film has high optical characteristics. It is known that the use is expected.

  In recent years, optical characteristics required for devices using light have become more sophisticated, and performance that is difficult to achieve with conventional techniques has been demanded. Among such required characteristics, there are characteristics that can be reached by increasing the inorganic components in the film, and therefore, an organic-inorganic composite film having a high inorganic fine particle content is required. However, in this case, since a large amount of inorganic fine particles are contained, the organic components constituting the film are inevitably reduced. Therefore, in the photolithography method of the photosensitive resin film by the conventional method, the development process is also performed. Unnecessary film portions could not be sufficiently removed, causing development residue, and pattern shape accuracy was not sufficient, and precise patterning was not possible.

  In a conventional method, Patent Document 1 describes that an acetylene alcohol surfactant is added to improve the wettability of a developer, but this developer uses a naphthoquinonediazide-based positive photoresist film. There is no disclosure about developing an organic-inorganic composite film having a high inorganic fine particle content, and no such effects or possibilities are taught. Patent Document 2 describes that an acetylene alcohol-based surfactant is added to a negative photoresist developer for wettability and antifoaming properties. In this case as well, organic compounds having a high inorganic fine particle content are described. There is no disclosure of developing an inorganic composite film, nor does it teach such effects or possibilities. Further, in Patent Document 3, it is pointed out that it is difficult to develop a photoresist in which a pigment is dispersed, and problems such as development residue and image edge disturbance occur, and acetylene alcohol-based surface activity is required for cleaning after development. However, the present invention is not related to a developing solution, and does not disclose that an organic-inorganic composite film having a high inorganic fine particle content is developed. There is no teaching.

JP-A-62-32453 JP-A-4-32849 JP 2005-146171 A

  Accordingly, the present invention provides a method of developing an organic-inorganic composite film by developing an organic-inorganic composite film having a high inorganic fine particle content and a developer capable of developing an organic-inorganic composite film having a high inorganic fine particle content. Let it be an issue.

The present invention relates to at least one inorganic material selected from the group consisting of silicon, metal, silicon or metal oxide, silicon or metal nitride, silicon or metal carbide, and a composite of at least two of them. After exposure of a photosensitive film containing 60 to 98% by weight of fine particles and 2 to 40% by weight of a photosensitive resin composition comprising an alkali-soluble resin and a photopolymerization initiator in terms of solid content, the HLB value according to the Griffin method Is a method for forming an organic-inorganic composite film, wherein development is performed with a developer containing 7 to 18 acetylene alcohol surfactant, an alkali component, and water.
The present invention also provides an organic-inorganic composite film containing 0.2 to 10% by weight of an acetylene alcohol surfactant having an HLB value of 7 to 18 by the Griffin method, 0.01 to 10% by weight of an alkali component, and the balance. Developer.

With the above configuration, the present invention is selected from the group consisting of silicon, metal, silicon or metal oxide, silicon or metal nitride, silicon or metal carbide, and a composite of at least two of them. An organic-inorganic composite film having a high inorganic fine particle content containing at least 60% by weight of at least one kind of inorganic fine particles can be developed with high pattern shape accuracy without generation of a development residue. Such an effect on an organic-inorganic composite film having a high inorganic fine particle content in a composition containing an acetylene alcohol surfactant, an alkali component and water has not been known so far, and it contains a large amount of inorganic fine particles, Since it is expected that a film having a small resin component cannot be sufficiently developed with a normal developer, it is an unexpected effect that it can be developed satisfactorily.
Therefore, the present invention provides a forming method capable of patterning a thin film having high optical properties, which is useful for improving the quality of a device using light, and a developer used therefor.

The organic-inorganic composite film developer of the present invention (hereinafter also simply referred to as the developer of the present invention) may contain the following components (A) to (E). Among these, the components (A) to (C) are essential components, and the components (D) and (E) are optional components to be added as necessary.
(A) Acetylene alcohol-based surfactant having an HLB value of 7 to 18 (B) Alkali component (C) Water (D) Organic solvent (E) Other additives

(A) Acetylene alcohol-based surfactant having an HLB value of 7-18 The acetylene alcohol-based surfactant used in the developer of the present invention has an HLB value of 7-18. The HLB value indicates the balance between the hydrophilic group and the lipophilic group contained in the surfactant molecule, and the higher the numerical value, the higher the solubility in water. The HLB value is a value obtained by the Griffin method. The HLB value by the Griffin method is determined by the following formula based on the formula weight and molecular weight of the hydrophilic group. Therefore, the HLB value in this case has a value in the range of 0-20.
HLB value = 20 × (sum of formula weight of hydrophilic group / molecular weight)

  A surfactant having an HLB value of less than 7 is insufficient in water solubility, so that uniform solubility in a developer cannot be obtained. Conversely, if it exceeds 18, the dissolution power of the uncured resin decreases during development. As a result, the development performance becomes insufficient. The HLB value is preferably 8-17, more preferably 10-16.

  As such a surfactant, for example, a compound obtained by adding an alkylene oxide to acetylene diol, specifically, for example, acetylene glycol (for example, 2,4,7,9-tetramethyl-5-decyne-4,7 -Diol) and an addition reaction of ethylene oxide with an addition amount of ethylene oxide of 35 to 90% by weight, for example, 2,4,7,9-tetramethyl-5-decyne-4 , 7-diol with 40% by weight of ethylene oxide added (HLB value 8), 65% by weight added (HLB value 13) or 85% by weight added (HLB value 17). Moreover, it is a mixture of the compound obtained by addition reaction of acetylene glycol and ethylene oxide, Comprising: The thing whose weighted average of the HLB value by the Griffin method of each compound is 7-18 may be sufficient. For example, the HLB value of a mixture obtained by mixing equal amounts of those having an HLB value of 6 and 13 by the Griffin method is 9.5, and such a mixture can also be used.

  In the developer of the present invention, the addition amount of the acetylene alcohol surfactant is preferably 0.2 to 10% by weight, more preferably 0.3 to 7% by weight, still more preferably 0.5 to 5%. % By weight, most preferably 0.55 to 5% by weight. If it is less than the range of 0.2 to 10% by weight, a long development time is required, and if it exceeds this range, separation tends to occur in the developer.

(B) Alkali component The alkali component used in the developer of the present invention may be either an organic alkali or an inorganic alkali. For example, alkali metal hydroxides such as lithium, sodium and potassium, carbonates, bicarbonates, phosphorus Inorganic alkalis such as acid salts or pyrophosphates; primary amines such as benzylamine and butylamine; secondary amines such as dimethylamine, diethanolamine and dibenzylamine; tertiary amines such as trimethylamine, triethylamine and triethanolamine Cyclic amines such as morpholine, piperazine, piperidine and pyridine, polyamines such as ethylenediamine and hexamethylenediamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylphenol Organic alkalis such as ammonium hydroxides such as phenylbenzylammonium hydroxide, sulfonium hydroxides such as trimethylsulfonium hydroxide, diethylmethylsulfonium hydroxide, dimethylbenzylsulfonium hydroxide, etc., or containing choline and silicate A buffer solution or the like may be used, and these may be used alone or in combination. Of these, tetramethylammonium hydroxide is preferred.

  In the developer of the present invention, the addition amount of the alkali component is preferably 0.01 to 10% by weight, more preferably 0.03 to 5% by weight, and still more preferably 0.05 to 1% by weight. . If it is less than the range of 0.01 to 10% by weight, a long development time is required. If this range is exceeded, the development time becomes extremely short and a development margin cannot be obtained, and film peeling or the like is likely to occur.

  In the developer of the present invention, the total amount of the component (A) and the component (B), which are essential components, is preferably 0.21 to 20% by weight, more preferably 0.33 to 12% by weight. Is 0.55 to 6% by weight. If it is less than 0.21% by weight, a long development time is required, and if it exceeds 20% by weight, the development time becomes extremely short or film peeling occurs.

(C) Water In the developer of the present invention, the water content is the balance of the total amount of the component (A) and the component (B), which are essential components, but contains any components described below. If it is, it is the balance after subtracting the blending amount. The water content varies depending on the blending amount of other components, but even when blending optional components, the lower limit of the water content is preferably 30% by weight or more, and generally depends on the blending amount of other components. For example, in an amount of 35% by weight or more, for example 40% by weight, 60% by weight or more.

(D) Organic solvent An organic solvent may be added to the developer of the present invention, and the type thereof is not particularly limited as long as it does not inhibit the dispersibility of the inorganic fine particles. Examples of the organic solvent include various organic solvents. For example, alcohols such as n-propyl alcohol, isopropyl alcohol, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diacetone alcohol, tetrahydrofurfuryl alcohol, cyclohexanol, ethylene glycol, polyethylene glycol, glycerin, methyl lactate, ethyl lactate Solvents, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether and other glycol alkyl ether solvents, ethylene glycol Monomethyl ether ace , Glycol glycol ether acetate solvents such as ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, triethylene glycol monomethyl ether acetate, triethylene glycol monoethyl ether acetate, tetrahydrofuran, dioxane, ethylene glycol Ether solvents such as dimethyl ether and diethylene glycol dimethyl ether; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ester solvents such as ethyl acetate, butyl acetate, amyl acetate and benzyl acetate; dimethylformamide, dimethylacetamide and N-methylpyrrolidone Nitrogen-containing solvents such as Door can be. Note that whether or not a certain organic solvent inhibits dispersibility depends on the polarity of the inorganic fine particles to be used, and therefore cannot be determined in general regardless of the inorganic fine particles. For example, in the case where silicon or metal oxide is used as the inorganic fine particles, isopropyl alcohol or the like can be used.

  In the developer of the present invention, the amount added when an organic solvent is used is usually preferably 40% by weight or less, more preferably 35% by weight or less, and further preferably 30% by weight or less in the developer. If it exceeds 40% by weight, film peeling tends to occur. In this case, the blending amount of water is the balance of the total amount of the added amount of the organic solvent, the component (A) and the component (B).

(E) Other additive Various additives can be mix | blended with the developing solution of this invention in the range which does not impair the effect of this invention. As such an additive, an antifoamer etc. are mentioned, for example.

  In the case of using an antifoaming agent, the addition amount is usually preferably 0.01 to 5% by weight, more preferably 0.05 to 3% by weight, and further preferably 0.1 to 2% in the developer. % By weight. If it is less than the range of 0.01 to 5% by weight, the defoaming effect is hardly obtained, and if it exceeds this range, the developability deteriorates. In this case, the blending amount of water is the balance of the additive amount of other additives, the additive amount of the organic solvent, if applicable, and the balance of the total amount of the component (A) and the component (B).

  A method for forming an organic-inorganic composite film using the developer of the present invention will be described below. The method of the present invention is at least one selected from the group consisting of silicon, metal, silicon or metal oxide, silicon or metal nitride, silicon or metal carbide, and a composite of at least two of them. After exposure of a photosensitive film containing 60 to 98% by weight of inorganic fine particles and 2 to 40% by weight of a photosensitive resin composition comprising an alkali-soluble resin and a photopolymerization initiator in terms of solid content, the griffin method is used. Development is performed with a developer containing an acetylene alcohol surfactant having an HLB value of 7 to 18, an alkali component, and water.

  Among the inorganic fine particles, examples of the metal fine particles include titanium, zirconium, niobium, aluminum, gold, silver, copper, iron, nickel, cobalt, and zinc. Examples of silicon or metal oxides include silicon dioxide, titanium oxide, zirconium oxide, niobium oxide, aluminum oxide, silver oxide, copper oxide, iron oxide, nickel oxide, cobalt oxide, and zinc oxide. Examples of silicon or metal nitrides include silicon nitride, titanium nitride, zirconium nitride, niobium nitride, and nickel nitride. Examples of silicon or metal carbides include silicon carbide, titanium carbide, and zirconium carbide. , Niobium carbide, nickel carbide and the like. Examples of the composite include a composite of silicon nitride and titanium nitride, a composite of metal such as silicon carbide and titanium, and a composite of silicon oxide and titanium oxide.

  The inorganic fine particles may be surface-treated, for example, treated with a silane coupling agent or the like. The above-described processing can be performed by a known method, and for example, can be performed by the method disclosed in the examples of the present specification or its application usually performed by those skilled in the art.

  The primary particle size of the inorganic fine particles is preferably 1 to 500 nm from the viewpoint of particle dispersibility during development, and more preferably 1 to 200 nm.

  The content of the inorganic fine particles in the photosensitive film is 60 to 98% by weight, more preferably 65 to 95% by weight, and further preferably 70 to 92% by weight. If the content is less than 60% by weight, the function of the inorganic fine particles is insufficient, and if it exceeds 98% by weight, the dispersibility and developability of the inorganic fine particles are deteriorated. Since the content of the inorganic fine particles depends on the use of the composite film, it can be determined in accordance with the use within the above range.

  The said photosensitive resin composition consists of resin and a photoinitiator. The resin is not particularly limited as long as it is a resin having film formability and alkali solubility. Specific examples of the resin include a novolak resin and an acrylate resin containing an alkali solubility promoting group (for example, a carboxyl group, a sulfonic acid group, or a hydroxyl group).

  Examples of the photopolymerization initiator include benzophenones, acetophenones, benzoins, α-hydroxy ketones, α-amino ketones, α-diketones, α-diketone dialkyl acetals, oxime esters, anthraquinones, thioxanthones, Mention may be made of phosphine oxides.

  As a compounding quantity of the said photoinitiator, it is 0.1 to 10 weight% normally with respect to 100 weight part of said resin.

  Content in the photosensitive film | membrane of the said photosensitive resin composition is 2 to 40 weight% in conversion of solid content. When the content is less than 2% by weight, the developability is deteriorated. On the other hand, when the content exceeds 40% by weight, the function by the inorganic fine particles is insufficient. More preferably, it is 5 to 35% by weight. The total content of the photosensitive resin composition in the photosensitive film and the content of the inorganic fine particles in the photosensitive film may be 100% by weight.

  The photosensitive film may contain a thermally crosslinkable resin or the like as desired. The content is usually about 0.1 to 10% by weight.

  The components including the predetermined amount of inorganic fine particles and the predetermined amount of the photosensitive resin composition, which are mixed using a solvent as necessary, are applied to a desired substrate by a known method and dried. A photosensitive film is formed. Examples of the solvent include acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, ethylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, methyl alcohol, ethyl alcohol, benzene, toluene, xylene and the like. it can. As the usage-amount of the said solvent, it is preferable to mix | blend so that the solid content concentration of a composition may be about 1 to 50 weight%. Moreover, you may use a dispersing agent as needed, for example, an anionic or nonionic high molecular type surfactant etc. can be mix | blended. The coating thickness may be appropriately set according to the purpose, but may be, for example, about 0.05 to 20 μm. After coating, it is preferable to pre-bake at about 80 to 100 ° C. for about 60 to 150 seconds for drying. Examples of the material for the substrate include glass, polyester resin, polycarbonate resin, acrylic resin, silicon, and semiconductor.

The photosensitive film is cured by exposure, and then an uncured portion is removed by development to form an organic-inorganic composite film. The exposure is performed on a desired part as necessary using a light source such as a carbon arc lamp, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, or a visible light laser. For example, pattern exposure through a photomask or pattern exposure by light beam scanning can be performed. The amount of irradiation energy can be appropriately determined depending on the light source to be used. However, for example, in the case of a high-pressure mercury lamp, it can usually be about 10 to 1000 mJ / cm ² .

  In the development performed after the exposure, the developer of the present invention is preferably used as the developer. The developing conditions may be 20 to 25 ° C. and 30 to 300 seconds, and the developer may be applied by a spraying method or a dipping method. After the development, a pure water rinse treatment can be performed as necessary. Further, a dehydration baking process may be performed at 80 to 150 ° C. for 60 to 300 seconds for drying.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to synthesis examples and examples, but the present invention is not limited to these examples.

Synthesis example 1
100 g of Super Titania F-2 (manufactured by Showa Denko KK) and 50 g of 3-methacryloylpropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503) are mixed with 2000 g of propylene glycol monomethyl ether acetate (PGMEA), Dispersion was performed for 5 hours in a paint shaker (manufactured by Red Devil) using zirconia beads as a medium to obtain a titanium oxide dispersion. Further, the dispersion is heated at 60 to 70 ° C. for 3 hours to carry out a surface treatment, and then the solvent is partially removed by concentration under reduced pressure to obtain a titanium oxide dispersion having a solid content of 20% by weight and an average particle size of 48 nm. Got.

Synthesis example 2
20 g of silicon nitride nanoparticles (manufactured by Sigma Aldrich Japan Co., Ltd.) and 10 g of 3-methacryloylpropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503) are mixed with 400 g of propylene glycol monomethyl ether acetate (PGMEA), Dispersion was performed for 5 hours with a paint shaker (manufactured by Red Devil) using zirconia beads as a medium to obtain a silicon nitride dispersion. Further, the dispersion is subjected to surface treatment by heating at 60 to 70 ° C. for 3 hours, and then part of the solvent is removed by concentration under reduced pressure to obtain a silicon nitride dispersion having a solid content of 20% by weight and an average particle size of 55 nm. Got.

Synthesis example 3
20 g of silicon oxide nanoparticles (manufactured by Sigma Aldrich Japan) and 10 g of 3-methacryloylpropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503) are mixed with 400 g of propylene glycol monomethyl ether acetate (PGMEA), Dispersion was performed for 5 hours with a paint shaker (manufactured by Red Devil) using zirconia beads as a medium to obtain a silicon oxide dispersion. Further, the dispersion was heated at 60 to 70 ° C. for 3 hours to perform surface treatment, and then part of the solvent was removed by concentration under reduced pressure to obtain a silicon oxide dispersion having a solid content of 20% by weight and an average particle size of 25 nm. Got.

Synthesis example 4
In a 300 ml four-necked flask, 120 g of AER-260 (bisphenol A type epoxy resin: manufactured by Asahi Kasei Chemicals Corporation), 600 mg of triethylbenzylammonium chloride as a catalyst, 30 mg of 2,6-diisobutylphenol as a polymerization inhibitor, and 36 g of acrylic acid Was dissolved by heating at 90 to 100 ° C. while blowing air at a rate of 10 mL / min. Next, the temperature was gradually raised to 120 ° C. During this time, the acid value was measured, and heating and stirring were continued until the acid value was less than 1.0 mg KOH / g to obtain a light yellow transparent and solid epoxy ester resin. It took 15 hours for the acid value to reach the target. To this epoxy ester resin, 65 g of propylene glycol monomethyl ether acetate (PGMEA) was added and dissolved, and then 15 g of biphenyltetracarboxylic dianhydride (BPDA) and 0.1 g of tetraethylammonium bromide were mixed. The reaction was carried out at 110-115 ° C. for 14 hours. In this manner, 193 g of a binder resin PGMEA solution (including 133 g of resin) was obtained. The disappearance of the acid anhydride was confirmed by IR spectrum.

Examples 1-15, Comparative Examples 1-4
Each component was mixed by the mixing | blending of Table 1, and each sample composition was obtained. Here, the blending ratio of each component shown in Table 1 describes the solid content (not including the solvent), and each PGMEA was added to prepare a solid content concentration of 20% by weight. This composition was applied onto a silicon substrate using a spinner and then pre-baked on a hot plate at 90 ° C. for 120 seconds to form a coating film having a thickness of about 1 μm.

A mask having a line-and-space pattern is placed on the surface of the silicon substrate having the coating film, and an ultraviolet ray having a light intensity of 9.5 mW / cm ² at a wavelength of 405 nm is applied at 500 mJ / mm using a 250 W high-pressure mercury lamp. Irradiation was performed so that the energy amount was cm ² .

Next, a dip development treatment was performed at 23 ° C. for 120 seconds using a developer obtained by mixing each component according to the formulation shown in Table 2. Here, the remaining part in which the total of the composition of each component shown in Table 2 is less than 100% is water. Then, the rinse process was performed with ultrapure water, and the substrate having the obtained thin film was subjected to a dehydration baking process on a hot plate at 100 ° C. for 120 seconds. The developability of the unexposed part and the patterning shape of the exposed part were observed and evaluated by ○ ×. The results are shown in Table 2. The evaluation criteria are as follows.
Developability (circle): The coating-film component does not remain in the unexposed part by visual confirmation.
X: The coating-film component remains in the unexposed part by visual confirmation.
Patterning shape ○: The exposed portion is not peeled off and is transferred according to the photomask pattern.
X: The exposed part is peeled off or the coating film component remains in the unexposed part.

The meanings of the abbreviations in Tables 1 and 2 are as follows.
IC907: Ciba Japan Co., Ltd. polymerization initiator TMAH: Tetramethylammonium hydroxide PGME: Propylene glycol monomethyl ether IPA: Isopropyl alcohol Surfynol 465: Air Products Co., Ltd., acetylene alcohol surfactant, HLB value 13
Surfynol 440: manufactured by Air Products, acetylene alcohol surfactant, HLB value 8
Olfin 4200: manufactured by Air Products, acetylene alcohol surfactant, HLB value 12
BYK-180: manufactured by BYK Japan, Inc., polymeric amine dispersant AQ-330: manufactured by Enomoto Kasei Co., Ltd., pigment dispersant Surfynol 420: manufactured by Air Products, Inc., acetylene alcohol surfactant, HLB value 4

  As can be seen from Table 2, Comparative Example 1 is a developer containing no surfactant but containing only an alkali component, but a high inorganic content composite film could not be developed. Further, Comparative Example 2 did not contain an alkali component and contained only a surfactant, and the composite film could not be developed. Further, even in Comparative Examples 3 and 4 which contain an alkali component but do not use the surfactant used in the present invention, development was not possible. Also in Comparative Example 5 using an acetylene alcohol surfactant having an HLB value other than 7 to 18, the composite film could not be developed.

  On the other hand, the developer of the present invention was excellent in both developability and patterning shape, and was able to develop a high inorganic content composite film.

Claims (5)

60 to at least one inorganic fine particle selected from the group consisting of silicon, metal, silicon or metal oxide, silicon or metal nitride, silicon or metal carbide, and a composite of at least two of them. After exposure of a photosensitive film containing 98 wt% and a photosensitive resin composition comprising an alkali-soluble resin and a photopolymerization initiator in an amount of 2 to 40 wt% in terms of solid content, the HLB value by the Griffin method is 7 to 18 A method for forming an organic-inorganic composite film, comprising developing with a developer containing an acetylene alcohol surfactant, an alkali component and water. The forming method according to claim 1, wherein the content of the acetylene alcohol surfactant is 0.2 to 10% by weight in the developer. The forming method according to claim 1, wherein the content of the alkali component is 0.01 to 10% by weight in the developer. The formation method according to claim 1, wherein the primary particle diameter of the inorganic fine particles is 1 to 500 nm. The formation method according to claim 1, wherein the exposure is performed by pattern exposure using a photomask or scanning.