JP2004079707A - Manufacture method of miniaturized t-shape electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method wherein a miniaturized T-shape electrode is manufactured inexpensively with a high throughput. <P>SOLUTION: The manufacturing method of the miniaturized T-shape electrode comprises a laminated resist forming process for forming a laminated resist comprising an ultraviolet ray sensitive resist layer on the uppermost layer of a T-shape gate electrode forming surface, an uppermost layer opening forming process for forming an uppermost layer opening by patterning only an ultraviolet ray sensitive resist layer by irradiating ultraviolet rays against the laminated resist, an uppermost layer opening contracting process for contracting the diameter of the same opening formed on the ultraviolet rays sensitive resist layer by applying a resist pattern thickening material on the ultraviolet ray resist layer, a lowermost layer opening forming process by transferring the uppermost layer opening formed on the ultraviolet ray sensitive resist layer to a lower layer and penetrate the laminated resist to form a lowermost layer opening in the lowermost layer of the laminated resist, a lowermost layer opening contracting process for contracting the opening in the lowermost layer of the laminated resist, and a T-shape electrode forming process for forming the T-shape electrode in the opening formed by penetrating the laminated resist. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a fine T-type electrode capable of manufacturing a fine T-type electrode at low cost and high throughput without using an expensive process such as electron beam drawing or SOR light exposure.
[0002]
[Prior art]
The fine T-type electrode is used as a gate electrode of a field-effect transistor in an advanced communication field using a high frequency such as a microwave or a millimeter wave band. In the case of such an application, it is necessary that the gate length at the root of the fine T-type electrode is 0.1 μm or less. In addition, in order to reduce the gate resistance as much as possible, the over-gate portion of the fine T-type electrode is generally designed to be larger than the root portion.
In the case of manufacturing the fine T-type electrode, using a laminated resist, an opening for determining the size of the gate length is formed below the laminated resist, and an opening for determining the size of the over gate portion is formed above the laminated resist. Has been done conventionally. In this case, a plurality of resist materials having different sensitivities are required to obtain a laminated resist in which openings having different sizes are formed in different layers. Further, when a lift-off method is used for manufacturing the fine T-type electrode, it is necessary to provide an intermediate layer resist for ensuring the ease of lift-off on the laminated resist. Conventionally, since there are many electron beam resists having different sensitivities, and since the gate length at the root of the fine T-type electrode needs to be 0.1 μm or less, the electron beam resist is used as the laminated resist. It has been generally practiced to manufacture a fine T-type electrode using high cost electron beam lithography. However, in this case, there is a problem that the fine T-shaped electrode cannot be manufactured at low cost and high throughput.
[0003]
Therefore, in order to solve the above problem, not only the electron beam resist but also a multi-layer resist combined with a photoresist having a higher throughput than electron beam drawing, and a part of light exposure is used for manufacturing the fine T-type electrode. The process used has been proposed. For example, in Japanese Unexamined Patent Publication No. Hei 7-153666, as shown in FIG. 23A, an opening 12 is formed by electron beam lithography in a lower resist 11 applied and formed on a substrate 20, and an upper resist 14 is formed thereon. To form a mixing layer 15 of the upper resist 14 and the lower resist 11. Then, as shown in FIG. 23 (b), a pattern having a T-shaped cross section is formed by exposing the upper resist 14 to ultraviolet rays 16, and thereafter, as shown in FIG. 23 (c), a T-type gate electrode is formed. It discloses that a fine T-type gate electrode is manufactured by forming and removing the lower resist 11 and the like as shown in FIG. Here, the overgate portion of the T-type gate electrode 18 is formed by light exposure, and an opening is formed by electron beam lithography using an electron beam resist as the lower layer resist 11 so that the gate length of the root portion of the T-type gate electrode 18 is reduced. Shortening has been proposed.
However, in this case, in order to obtain a gate length of 0.1 μm or less, the opening 12 provided in the lower resist 11 must be formed by electron beam lithography, which causes a problem of high cost and low throughput.
[0004]
On the other hand, Japanese Patent Application Laid-Open No. H11-307549 discloses that a fine T-type electrode is formed by performing fine patterning using an i-line stepper at high throughput and at the same level as EB exposure. As shown in FIG. 24A, an EB exposure resist film 23, a buffer film 24, and an i-ray exposure resist film 25 are sequentially formed on the substrate 20 by application, and thereafter, the i-ray exposure resist film 25 is formed. Then, i-line exposure is performed on the buffer film 24 to perform patterning, thereby forming a first opening 25a. Next, as shown in FIG. 24B, the EB exposure resist film 23 is dry-etched using the i-ray exposure resist film 25 as a mask, so that the EB exposure resist film 23 is exposed to the i-ray exposure resist. A second opening 23a to which the pattern of the film 25 has been transferred is formed. Next, as shown in FIG. 24C, a chemically amplified third resist film 26 capable of forming the EB exposure resist film 23 and the mixing layer 27 is applied to the entire surface of the EB exposure resist film 23. . Thereby, the wall surface of the second opening 23a is covered with the mixing layer 27, and the opening width of the second opening 23a is reduced. Thereafter, as shown in FIG. 24D, i-line exposure is performed on the third resist film 26 to perform patterning. It is disclosed that a T-type gate electrode is obtained by forming an electrode and removing the resist film. In this case, low cost is expected in that only light exposure by an i-line stepper is used and electron beam drawing is not performed.
However, it is necessary to perform the exposure using the i-line stepper twice, when the i-ray exposure resist film 25 is opened and when the third resist film 26 is opened, which is not sufficient from the viewpoint of throughput. Absent. The opening of the i-line exposure resist film 25 is about 0.4 μm, and the first opening 23a has the same size, but the opening is reduced by the mixing layer 27 from this size to 0.1 μm or less. The problem is that the dimensional controllability is poor and difficult. Further, since the T-shaped configuration is formed by the two layers of the third resist film 26 and the mixing layer 27, it is not easy to lift off the resist film at the time of manufacturing a fine T-shaped gate electrode of 0.1 μm or less. There is.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to solve the conventional problems and achieve the following objects. That is, the present invention provides a method of manufacturing a fine T-type electrode that can manufacture a fine T-type electrode at low cost and with high throughput without using an expensive process such as electron beam drawing or SOR light exposure. Aim.
[0006]
[Means for Solving the Problems]
The present invention provides a laminated resist forming step of forming a laminated resist including a light-sensitive photoresist layer on at least the uppermost layer on a T-type gate electrode forming surface, and irradiating the laminated resist with light to form the photoresist layer. Forming an uppermost opening by patterning only the uppermost opening, and reducing the diameter of the uppermost opening formed in the photoresist layer by applying a resist pattern thickening material to the photoresist layer. An uppermost layer opening reducing step of transferring the uppermost layer opening formed in the photoresist layer to a lower layer of the photoresist layer, penetrating the laminated resist, and forming a lowermost layer opening in the lowermost layer of the laminated resist. Forming a lowermost layer opening, and a lowermost layer opening reducing step of reducing the size of the lowermost layer opening in the lowermost layer of the laminated resist; A method for producing a fine T-shaped electrode, characterized in that the opening formed through the multi-layer resist comprises a T-type electrode forming step of forming a T-shaped electrode.
In the laminated resist forming step, a laminated resist having a light-sensitive photoresist layer on at least the uppermost layer is formed on the T-type gate electrode formation surface. In the uppermost layer opening forming step, a resist pattern thickening material is applied to the photoresist layer, and the diameter of the uppermost layer opening formed in the photoresist layer is reduced. In the lowermost layer opening forming step, the uppermost layer opening formed in the photoresist layer is transferred to a lower layer of the photoresist layer, the laminated resist is penetrated, and a lowermost layer opening in the lowermost layer of the laminated resist is formed. Is done. In the lowermost layer opening reducing step, the size of the lowermost layer opening in the lowermost layer of the laminated resist is reduced. In the T-type electrode forming step, a T-type electrode is formed in an opening formed through the laminated resist. As described above, a fine T-type electrode having a gate length of about 0.1 μm or less can be manufactured at low cost and high throughput.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
(Method of manufacturing fine T-shaped electrode)
The method for manufacturing a fine T-type electrode according to the present invention includes a laminated resist forming step, an uppermost layer opening forming step, an uppermost layer opening reducing step, a lowermost layer opening forming step, a lowermost layer opening reducing step, a T-type electrode forming step. And a step appropriately selected as necessary.
[0008]
-Laminated resist formation process-
The step of forming a laminated resist is a step of forming a laminated resist having a light-sensitive photoresist layer on at least the uppermost layer on the surface on which the T-type gate electrode is formed.
[0009]
The T-type gate electrode formation surface is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a gate electrode formation surface in various semiconductor devices and the like. A gate electrode formation surface of a field-effect transistor in an advanced communication field using a high frequency such as a waveband is particularly preferably used.
[0010]
The laminated resist is not particularly limited except that it has a light-sensitive photoresist layer on the uppermost layer, and the number of layers, the type of resist, the thickness of each layer, the opening diameter, and the like are appropriately selected depending on the purpose. Can be.
[0011]
The photoresist for forming the photoresist layer (hereinafter sometimes referred to as the “top layer”) is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include a g-line resist and an i-line resist. , KrF resist, ArF resist, F2 resist, and the like. Among them, i-line resist is preferable from the viewpoint of manufacturing a fine T-type electrode at low cost and high throughput. These may use a commercial item.
[0012]
The number of layers of the laminated resist is not particularly limited and may be appropriately selected depending on the intended purpose. (1) The number of layers for forming the opening for forming the root portion of the fine T-type electrode is the same as that of the lowermost layer. A three-layer structure including an upper layer for forming an overgate portion of the fine T-type electrode and the uppermost layer; (2) the lowermost layer and an intermediate layer for achieving lift-off easiness A four-layer structure of the upper layer and the uppermost layer (see FIG. 1); (3) the lowermost layer, the upper layer, an insulating layer having excellent etching resistance provided immediately above the uppermost layer, and the uppermost layer (4) a five-layer structure of the lowermost layer, an intermediate layer for achieving lift-off easiness, the upper layer, the insulating layer, and the uppermost layer (see FIG. 2), and the like. Are preferred.
[0013]
The material of the resist of each layer constituting the laminated resist is not particularly limited except that the uppermost layer is a photoresist, but a layer immediately below the uppermost layer, preferably a layer other than the uppermost layer, The material can be appropriately selected from materials which are insensitive to light to which the uppermost layer is exposed.
[0014]
The material of the lowermost layer is not particularly limited and may be appropriately selected depending on the intended purpose.A material that is not sensitive to light is preferable, and a material that can be thickened by the resist pattern thickening material is more preferable. For example, a polymethyl methacrylate (PMMA) -based resist is preferably used.
[0015]
The material of the intermediate layer is not particularly limited and may be appropriately selected depending on the intended purpose. From the viewpoint of efficient formation of the overgate portion of the fine T-type electrode, a material that can be side-etched is used. More preferably, for example, a resist containing polydimethylglutarimide (PMGI) as a main component is preferably used.
[0016]
The material of the upper layer is not particularly limited and may be appropriately selected depending on the intended purpose.A material which is not sensitive to light is preferable, such as a polystyrene polymer-containing resist containing a polystyrene polymer and an acrylic resin. Are preferred.
Commercially available products can be appropriately used as these materials.
[0017]
The material of the insulating layer is not particularly limited and may be appropriately selected depending on the purpose. For example, a material that can be deposited and formed by a plasma CVD method is preferable, and specifically, SiN, SiON, and the like are preferable. Preferred examples are given. Providing the insulating layer in the laminated resist is advantageous in that the shape of the uppermost layer opening can be maintained even when the etching resistance of the photoresist layer (uppermost layer) is not sufficient. It is.
[0018]
The thickness of each layer constituting the laminated resist is not particularly limited and can be appropriately selected depending on the purpose. Thickness conditions conventionally used for manufacturing a T-type electrode can be employed.
[0019]
-Top layer opening forming process-
The uppermost layer opening forming step is a step of irradiating the laminated resist with light and patterning only the uppermost layer to form an uppermost layer opening.
[0020]
The light applied to the laminated resist is not particularly limited and may be appropriately selected depending on the type of the resist material forming the uppermost layer in the laminated resist. Examples thereof include g-line, i-line, and KrF excimer laser. , ArF excimer laser, F2 excimer laser and the like. Among them, ultraviolet rays are preferable, and from the viewpoint of producing a fine T-type electrode at low cost and high throughput, i-line is particularly preferable.
The exposure machine for irradiating light is not particularly limited and can be appropriately selected depending on the purpose. For example, an i-line stepper is preferably used. In patterning the uppermost layer, a photomask or the like can be suitably used.
[0021]
The diameter of the opening formed in the laminated resist is about 0.35 to 0.50 μm in consideration of, for example, shortening the gate length of the fine T-type electrode and performing exposure such as i-line in the uppermost layer. It is preferred that
[0022]
By irradiating the laminated resist with light in the uppermost layer opening forming step, only the photoresist layer (uppermost layer) can be patterned to form an uppermost layer opening.
[0023]
-Top layer opening reduction process-
In the uppermost layer opening reduction step, a diameter of the uppermost layer opening formed in the photoresist layer (uppermost layer) is reduced by applying a resist pattern thickening material to the photoresist layer (uppermost layer). It is a process.
[0024]
−−Resist pattern thickening material−−
The resist pattern thickening material contains a resin, a cross-linking agent, and a surfactant, and further includes a water-soluble aromatic compound and an aromatic compound which are appropriately selected as necessary. Resin, organic solvent, and other components.
[0025]
The resist pattern thickening material is water-soluble or alkali-soluble.
The resist pattern thickening material may be in the form of an aqueous solution, colloid liquid, emulsion liquid, or the like, but is preferably in the form of an aqueous solution.
[0026]
The resin is not particularly limited and may be appropriately selected depending on the intended purpose. However, it is preferably water-soluble or alkali-soluble, and a water-soluble crosslinking agent which can or does not cause a crosslinking reaction More preferably, it can be mixed with.
[0027]
When the resin is a water-soluble resin, the water-soluble resin is preferably a water-soluble resin that dissolves in 0.1 g or more in water at 25 ° C.
As the water-soluble resin, for example, polyvinyl alcohol, polyvinyl acetal, polyvinyl acetate, polyacrylic acid, polyvinylpyrrolidone, polyethyleneimine, polyethylene oxide, styrene-maleic acid copolymer, polyvinylamine, polyallylamine, oxazoline group-containing water-soluble Resins, water-soluble melamine resins, water-soluble urea resins, alkyd resins, sulfonamide resins and the like.
[0028]
When the resin is alkali-soluble, the alkali-soluble resin is preferably a resin exhibiting alkali solubility of 0.1 g or more in 2.38% TMAH aqueous solution at 25 ° C.
Examples of the alkali-soluble resin include a novolak resin, a vinylphenol resin, polyacrylic acid, polymethacrylic acid, poly p-hydroxyphenyl acrylate, poly p-hydroxyphenyl methacrylate, and a copolymer thereof.
[0029]
The resins may be used alone or in combination of two or more. Among them, polyvinyl alcohol, polyvinyl acetal, polyvinyl acetate and the like are preferable.
[0030]
The content of the resin in the resist pattern thickening material varies depending on the type and content of the cross-linking agent and the like and cannot be specified unconditionally, but can be appropriately determined according to the purpose.
[0031]
The cross-linking agent is not particularly limited and may be appropriately selected depending on the intended purpose. However, a water-soluble cross-linking agent that generates cross-linking by heat or acid is preferable, and an amino cross-linking agent is, for example, preferably.
Preferable examples of the amino-based crosslinking agent include melamine derivatives, urea derivatives, and uryl derivatives. These may be used alone or in combination of two or more.
Examples of the urea derivative include urea, alkoxymethylene urea, N-alkoxymethylene urea, ethylene urea, ethylene urea carboxylic acid, and derivatives thereof.
Examples of the melamine derivative include alkoxymethylmelamine and derivatives thereof.
Examples of the uryl derivative include benzoguanamine, glycoluril, and derivatives thereof.
[0032]
The content of the cross-linking agent in the resist pattern thickening material varies depending on the type and content of the resin and cannot be unconditionally defined, but can be appropriately determined according to the purpose.
[0033]
The surfactant is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include a nonionic surfactant, a cationic surfactant, an anionic surfactant, and an amphoteric surfactant. Can be These may be used alone or in combination of two or more. Among these, nonionic surfactants are preferred because they do not contain metal ions.
[0034]
As the nonionic surfactant, those selected from an alkoxylate surfactant, a fatty acid ester surfactant, an amide surfactant, an alcohol surfactant, and an ethylenediamine surfactant are preferably used. No. In addition, as these specific examples, a polyoxyethylene-polyoxypropylene condensate compound, a polyoxyalkylene alkyl ether compound, a polyoxyethylene alkyl ether compound, a polyoxyethylene derivative compound, a sorbitan fatty acid ester compound, a glycerin fatty acid ester compound, Primary alcohol ethoxylate compound, phenol ethoxylate compound, nonylphenol ethoxylate type, octylphenol ethoxylate type, lauryl alcohol ethoxylate type, oleyl alcohol ethoxylate type, fatty acid ester type, amide type, natural alcohol type, ethylenediamine type, Secondary alcohol ethoxylates and the like can be mentioned.
[0035]
The cationic surfactant is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include an alkyl cation surfactant, an amide quaternary cation surfactant, and an ester quaternary cation surfactant. Surfactants and the like.
[0036]
The amphoteric surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include an amine oxide-based surfactant and a betaine-based surfactant.
[0037]
The content of the above surfactant in the resist pattern thickening material varies depending on the type and content of the resin, the cross-linking agent, and the like, and cannot be specified unconditionally, but is appropriately determined according to the purpose. You can choose.
[0038]
It is preferable that the resist pattern thickening material contains a water-soluble aromatic compound because the etching resistance of the uppermost layer opening can be significantly improved.
The water-soluble aromatic compound is not particularly limited as long as it is an aromatic compound and shows water solubility, and can be appropriately selected according to the purpose. A water-soluble substance which dissolves at least 3 g in 100 g of water at 25 ° C. is more preferable, and a water-soluble substance which dissolves at least 5 g in 100 g of water at 25 ° C. is particularly preferable.
[0039]
Examples of the water-soluble aromatic compound include, for example, polyphenol compounds, aromatic carboxylic acid compounds, naphthalene polyhydric alcohol compounds, benzophenone compounds, flavonoid compounds, porphine, water-soluble phenoxy resins, aromatic-containing water-soluble dyes, derivatives thereof, These glycosides and the like can be mentioned. These may be used alone or in combination of two or more.
[0040]
Examples of the polyphenol compound and derivatives thereof include catechin, anthocyanidin (pelargodine type (4′-hydroxy), cyanidin type (3 ′, 4′-dihydroxy), and delphinidin type (3 ′, 4 ′, 5′-trihydroxy). )), Flavan-3,4-diol, proanthocyanidin, resorcin, resorcin [4] arene, pyrogallol, gallic acid, derivatives or glycosides thereof.
[0041]
Examples of the aromatic carboxylic acid compound and its derivative include salicylic acid, phthalic acid, dihydroxybenzoic acid, tannin, derivatives and glycosides thereof.
[0042]
Examples of the naphthalene polyhydric alcohol compound and derivatives thereof include naphthalene diol, naphthalene triol, derivatives thereof, and glycosides.
[0043]
Examples of the benzophenone compound and its derivatives include alizarin yellow A, derivatives and glycosides thereof.
[0044]
Examples of the flavonoid compound and its derivative include flavone, isoflavone, flavanol, flavonone, flavonol, flavan-3-ol, auron, chalcone, dihydrochalcone, quercetin, and derivatives or glycosides thereof.
[0045]
Among the water-soluble aromatic compounds, those having two or more polar groups are preferable, those having three or more polar groups are more preferable, and those having four or more polar groups are particularly preferable in terms of excellent water solubility.
The polar group is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include a hydroxyl group, a carboxyl group, a carbonyl group, and a sulfonyl group.
[0046]
The content of the water-soluble aromatic compound in the resist pattern thickening material can be appropriately determined according to the type and content of the resin, the crosslinking agent, and the like.
[0047]
It is preferable that the resist pattern thickening material contains a resin partially containing an aromatic compound, since the etching resistance of the uppermost layer opening can be significantly improved.
The resin partially containing the aromatic compound is not particularly limited and may be appropriately selected depending on the purpose. However, it is preferable that a crosslinking reaction can be caused, and for example, a polyvinyl aryl acetal resin , A polyvinyl aryl ether resin, a polyvinyl aryl ester resin, a derivative thereof, and the like, preferably at least one selected from these, and an acetyl group in terms of exhibiting appropriate water solubility to alkali solubility. Are more preferable. These may be used alone or in combination of two or more.
[0048]
The polyvinyl aryl acetal resin is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include β-resorcin acetal.
The polyvinyl aryl ether resin is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include 4-hydroxybenzyl ether.
The polyvinyl aryl ester resin is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include benzoic acid esters.
[0049]
The method for producing the polyvinyl aryl acetal resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a production method utilizing a known polyvinyl acetal reaction is preferably exemplified. The production method is, for example, a method in which polyvinyl alcohol and an aldehyde in a stoichiometrically required amount are acetalized in the presence of an acid catalyst. Specifically, US Pat. 897, 5,262,270, and JP-A-5-78414.
[0050]
The method for producing the polyvinyl aryl ether resin is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include a copolymerization reaction of a corresponding vinyl aryl ether monomer and vinyl acetate, and the presence of a basic catalyst. Examples thereof include an etherification reaction of polyvinyl alcohol with an aromatic compound having a halogenated alkyl group (a reaction of Williamson's ether synthesis), and specifically, JP-A-2001-40086 and JP-A-2001-181383. And the method disclosed in JP-A-6-116194.
[0051]
The method for producing the polyvinyl aryl ester resin is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include a copolymerization reaction of a corresponding vinyl aryl ester monomer and vinyl acetate, and the presence of a basic catalyst. Examples of the reaction include an esterification reaction between polyvinyl alcohol and an aromatic carboxylic acid halide compound.
[0052]
The aromatic compound in the resin partially having the aromatic compound is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a monocyclic aromatic benzene derivative and a pyridine derivative. And compounds in which a plurality of aromatic rings are linked (polycyclic aromatics such as naphthalene and anthracene).
[0053]
The aromatic compound in the resin partially having the aromatic compound is, for example, a hydroxyl group, a cyano group, an alkoxyl group, a carboxyl group, an amino group, an amide group, an alkoxycarbonyl group, a hydroxyalkyl group, a sulfonyl group, an acid It is preferable to have at least one functional group such as an anhydride group, a lactone group, a cyanate group, an isocyanate group, and a ketone group and at least one saccharide derivative from the viewpoint of appropriate water solubility, and a hydroxyl group, an amino group, a sulfonyl group, a carboxyl group More preferably, it has at least one functional group selected from groups and groups derived from these derivatives.
[0054]
The molar content of the aromatic compound in the resin partially having the aromatic compound is not particularly limited as long as it does not affect the etching resistance, and may be appropriately selected depending on the intended purpose. Is required, it is preferably at least 5 mol%, more preferably at least 10 mol%.
The molar content of the aromatic compound in the resin partially containing the aromatic compound can be measured using, for example, NMR.
[0055]
The content of the resin having a part of the aromatic compound in the resist pattern thickening material can be appropriately determined according to the type and content of the resin, the crosslinking agent, and the like.
[0056]
By including the organic solvent in the resist pattern thickening material, the solubility of the resin, the crosslinking agent, and the like in the resist pattern thickening material can be improved.
[0057]
The organic solvent is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include an alcohol-based organic solvent, a chain ester-based organic solvent, a cyclic ester-based organic solvent, a ketone-based organic solvent, and a chain ether. Organic solvents, cyclic ether organic solvents, and the like.
[0058]
Examples of the alcohol-based organic solvent include methanol, ethanol, propyl alcohol, isopropyl alcohol, and butyl alcohol.
Examples of the chain ester organic solvent include ethyl lactate and propylene glycol methyl ether acetate (PGMEA).
Examples of the cyclic ester organic solvent include lactone organic solvents such as γ-butyrolactone.
Examples of the ketone-based organic solvent include ketone-based organic solvents such as acetone, cyclohexanone, and heptanone.
Examples of the chain ether organic solvent include ethylene glycol dimethyl ether.
Examples of the cyclic ether include tetrahydrofuran and dioxane.
[0059]
These organic solvents may be used alone or in combination of two or more. Among them, those having a boiling point of about 80 to 200 ° C. are preferable in that the thickness can be finely increased.
[0060]
The content of the organic solvent in the resist pattern thickening material can be appropriately determined according to the type and content of the resin, the crosslinking agent, the surfactant, and the like.
[0061]
The other components are not particularly limited as long as they do not impair the effects of the present invention, and may be appropriately selected depending on the intended purpose. Various known additives, for example, thermal acid generators, amines, amides, A quencher represented by ammonium chlorine and the like can be mentioned.
The content of the other components in the resist pattern thickening material can be appropriately determined according to the type and content of the resin, the crosslinking agent, and the like.
[0062]
When the resist pattern thickening material is applied to the uppermost layer opening and crosslinked, the uppermost layer opening is thickened, a surface layer is formed on the uppermost layer opening, and the diameter of the uppermost layer opening is reduced. . As a result, a finer uppermost layer opening is formed without using electron beam drawing or the like, exceeding the exposure limit of the light source of the exposure apparatus used for forming the uppermost layer opening.
[0063]
At this time, the amount of thickening of the uppermost layer opening, that is, the amount of reduction of the diameter of the uppermost layer opening is the composition, composition ratio, compounding amount, concentration, viscosity, coating thickness, and coating thickness of the resist pattern thickening material. By appropriately adjusting the baking temperature, the baking time, and the like, the temperature can be controlled to a desired range.
The composition, composition ratio, compounding amount, concentration, viscosity, and the like of the resist pattern thickening material are not particularly limited, and can be appropriately selected depending on the purpose.
As the total content of components other than water in the resist pattern thickening material, the thickness of the uppermost layer opening, that is, from the viewpoint of controlling the amount of reduction in the diameter of the uppermost layer opening, usually 1 to 80 mass%, preferably 5 to 50 mass%, more preferably 10 to 20 mass%.
[0064]
After the coating, a developing treatment can be performed. By performing the developing process, it is possible to remove the excess resist pattern thickening material which did not form a mixing layer with the uppermost layer.
The developing process may be a water developing process or a developing process using a weak alkaline aqueous solution. However, the water developing process is preferable because the developing process can be performed efficiently at low cost.
[0065]
The method for applying the resist pattern thickening material is not particularly limited, and can be appropriately selected from known application methods depending on the purpose. For example, a spin coating method is preferably used. . In the case of the spin coating method, the conditions are, for example, a rotation speed of about 100 to 10000 rpm, preferably 800 to 5000 rpm, a time of about 1 second to 10 minutes, and preferably 1 second to 90 seconds.
The coating thickness at the time of the coating is usually about 100 to 10000, preferably about 2000 to 5000.
At the time of the application, the surfactant may be separately applied before the resist pattern thickening material is applied without being contained in the resist pattern thickening material.
[0066]
Pre-baking (heating / drying) the applied resist pattern thickening material during or after the application is performed at the interface between the uppermost layer and the resist pattern thickening material. Mixing (impregnation) of the material into the uppermost layer is preferable in that it can be efficiently generated.
The conditions and method of the prebaking (heating / drying) are not particularly limited as long as the uppermost layer is not softened, and can be appropriately selected depending on the purpose. For example, the temperature is 40 to 120 ° C. About 70 to 100 ° C., and the time is about 10 to 5 minutes, preferably 40 to 100 seconds.
[0067]
Further, after the pre-baking (heating and drying), the applied resist pattern thickening material is subjected to cross-linking baking (cross-linking reaction) at the interface between the uppermost layer and the resist pattern thickening material. This is preferable in that the cross-linking reaction of the mixed (impregnated) portion can proceed efficiently.
The conditions and method of the cross-linking baking (cross-linking reaction) are not particularly limited and can be appropriately selected depending on the purpose. However, temperature conditions which are usually higher than those of the pre-baking (heating and drying) are employed. Is done. As conditions for the crosslinking baking (crosslinking reaction), for example, the temperature is about 70 to 150 ° C., preferably 90 to 130 ° C., and the time is about 10 to 5 minutes, and preferably 40 to 100 seconds.
[0068]
Further, after the crosslinking bake (crosslinking reaction), it is preferable to perform a development process on the applied resist pattern thickening material. In this case, a portion of the applied resist pattern thickening material that is not cross-linked to the uppermost layer or a portion where cross-linking is weak (highly water-soluble portion) is dissolved and removed, and the thickened resist pattern is developed (obtained). ) Is preferable.
[0069]
-Lowermost layer opening forming process-
The lowermost layer opening forming step transfers the uppermost layer opening formed in the photoresist layer to a lower layer of the photoresist layer, penetrates the laminated resist, and forms a lowermost layer opening in the lowermost layer of the laminated resist. This is the step of doing.
[0070]
The method of transferring the uppermost layer opening to the lower layer (the upper layer, the intermediate layer, the lowermost layer, etc.) of the photoresist layer (the uppermost layer) is not particularly limited, and can be appropriately selected depending on the purpose. However, etching and the like are preferable.
The etching method is not particularly limited and may be appropriately selected from known methods according to the purpose. Examples thereof include dry etching and plasma ashing. Among these, dry etching is preferable. Is preferred.
The etching conditions are not particularly limited and can be appropriately selected depending on the purpose.
The gas used for the etching is not particularly limited and can be appropriately selected depending on the intended purpose; however, an etching gas containing at least one kind of oxygen atom, fluorine atom, and chlorine atom in the molecule, oxygen plasma, and the like are preferable. It is listed.
[0071]
The plasma ashing is preferably oxygen plasma ashing, and is particularly suitable when the upper layer is a polystyrene polymer-containing resist. In this case, the intermediate layer is preferably exposed and developed, and the lowermost layer is also preferably subjected to oxygen plasma ashing.
[0072]
In the lowermost layer opening forming step, the uppermost layer in which the uppermost layer opening is formed functions as a mask, and layers other than the uppermost layer (the upper layer and the intermediate layer) exposed from the uppermost layer opening in the uppermost layer , The lowermost layer) is etched away. As a result, the uppermost layer opening is transferred to a layer other than the uppermost layer, the multilayer resist is penetrated, and finally, a lowermost layer opening is formed in the lowermost layer of the multilayer resist. At this time, the upper layer and the intermediate layer are side-etched, and have a larger opening diameter than the uppermost layer opening. The openings formed in the upper layer and the intermediate layer serve as spaces for forming the overgate portion.
[0073]
In the present invention, after the lowermost layer opening forming step and before the lowermost layer opening reducing step, a side etching step of side-etching the opening of the intermediate layer using the intermediate layer soluble solution, A heat treatment step of forming a tapered structure in the lowermost layer opening by subjecting the heat treatment to a heat treatment.
The side etching step is preferable in that the intermediate layer is side-etched in the first stage, and a space for forming an overgate portion can be secured in an opening formed in the laminated resist.
[0074]
-Lowermost opening reduction process-
The lowermost opening reduction step is a step of reducing the size of the lowermost opening in the lowermost layer of the laminated resist.
[0075]
The method of reducing the size of the lowermost layer opening is not particularly limited and can be appropriately selected depending on the purpose.For example, by applying the resist pattern thickening material to the lowermost layer opening, A method of reducing the opening diameter, a method of reducing the opening diameter by heating the lowermost opening, and the like, among these, by applying the resist pattern thickening material to the lowermost opening, A method of reducing the opening diameter is preferable. The method of reducing the opening diameter by heating the lowermost layer opening can be suitably employed when the lowermost layer is formed of a polymethyl methacrylate (PMMA) -based resist.
[0076]
In the lowermost layer opening reduction step, the lowermost layer opening in the lowermost layer of the multilayer resist is thickened, and the size of the opening is reduced. In the lowermost layer opening reducing step, the above-described resist pattern thickening material can be suitably used.In this case, when the resist pattern thickening material is applied to the lowermost layer opening and crosslinked, the The lowermost opening is made thicker, a surface layer is formed on the lowermost opening, and the diameter (size) of the lowermost opening is reduced. As a result, without using electron beam drawing or the like, a finer lower layer opening is formed that exceeds the exposure limit of the light source of the exposure apparatus used for forming the uppermost layer opening.
[0077]
At this time, the amount of thickening of the lowermost layer opening, that is, the amount of reduction of the diameter of the lowermost layer opening is the composition, composition ratio, blending amount, concentration, viscosity, coating thickness, and coating thickness of the resist pattern thickening material. By appropriately adjusting the baking temperature, the baking time, and the like, the temperature can be controlled to a desired range.
The composition, composition ratio, compounding amount, concentration, viscosity, and the like of the resist pattern thickening material are not particularly limited, and can be appropriately selected depending on the purpose.
As the total content of components other than water in the resist pattern thickening material, the thickness of the uppermost layer opening, that is, from the viewpoint of controlling the amount of reduction in the diameter of the uppermost layer opening, usually 1 to 80 mass%, preferably 5 to 50 mass%, more preferably 10 to 20 mass%.
[0078]
-T-type electrode forming process-
The T-type electrode forming step is a step of forming a T-type electrode in an opening formed through the laminated resist.
The method for forming the T-type electrode is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a vapor deposition method is preferably used.
The metal material to be deposited by the vapor deposition method can be appropriately selected from those known as electrode materials. For example, Ti, Pt, Au and the like are preferable. These may be used alone or in combination of two or more. In addition, these metals may be laminated to form the T-type electrode. In this case, for example, a mode in which the T-type electrode is formed by a laminated film of Ti, Pt, and Au is preferably exemplified.
[0079]
After the formation of the T-type electrode, it is necessary to remove the laminated resist. Examples of the method for removing the laminated resist include a lift-off method and an etching method. Are preferred. The conditions and the like of these methods are not particularly limited, and can be appropriately selected from known conditions and the like.
[0080]
In the T-type electrode forming step, a T-type electrode is formed in an opening formed through the laminated resist. Specifically, a root portion of the fine T-type electrode is formed at the lowermost layer opening, and the opening in the side-etched intermediate layer is a space for forming an overgate portion. Then, the laminated resist is removed to obtain a fine T-shaped electrode.
[0081]
Next, a specific embodiment of the method for manufacturing a fine T-type electrode of the present invention will be described with reference to the drawings.
[0082]
(First embodiment)
As shown in FIG. 1, a PMMA-based resist 2 (a polymethyl methacrylate-based resist) and a PMGI resist 3 (a resist mainly composed of polydimethylglutarimide) are formed on a formation surface 1 (here, a semiconductor surface) of a fine T-type electrode. ), A resist 4 containing a polystyrene polymer (an electron beam resist containing a polystyrene polymer and an acrylic resin) and an i-ray resist 5 were sequentially applied to form a laminated resist. The above is the laminated resist forming step. In addition, as shown in FIG. 2, an insulating layer 30 may be provided between the polystyrene polymer-containing resist 4 (electron beam resist containing a polystyrene polymer and an acrylic resin) and the i-line resist 5.
[0083]
Next, as shown in FIG. 3, an i-line 6 was selectively irradiated onto the i-line resist 5, and an opening for forming a fine T-type electrode was patterned by photolithography. Then, an opening 5a was formed on the i-line resist 5 as shown in FIG. The opening dimension (opening diameter) of the opening 5a varies depending on the exposure conditions, but here is about 0.35 μm to 0.50 μm. This opening 5a is the uppermost layer opening. The above is the uppermost layer opening forming step.
[0084]
Next, a resist pattern thickening material is applied on the i-line resist 5 and the pre-baking is performed. When the i-line resist 5 and the resist pattern thickening material are mixed at the interface of the opening 5a, the mixing layer 7 is formed. It is formed. Thereafter, when the cross-linking baking is performed at a higher temperature than the pre-baking, the mixing layer 7 is cross-linked. In this state, when development was performed using water, IPA, or a weak alkaline aqueous solution, the resist pattern thickening material other than the crosslinked mixing layer 7 was dissolved and removed. As a result, as shown in FIG. 5, the opening dimension (opening diameter) of the opening 5a was reduced. The above is the uppermost layer opening reduction step.
[0085]
In the uppermost layer opening reduction step, by adjusting the type, composition, composition ratio, blending amount, concentration, etc. of the resin and the cross-linking agent contained in the resist pattern thickening material, or the resist pattern thickness By appropriately changing the application conditions of the fleshy material, or by adjusting the temperature and time of baking performed after application, the thickness of the mixing layer and the degree of crosslinking in the mixing layer can be changed, The amount of the resist pattern thickening material to be dissolved and removed by the treatment can be changed, and the reduction of the opening size (opening diameter) of the opening 5a can be controlled to a desired degree.
Specifically, as the resist pattern thickening material, a material containing 5 to 40% by weight in total of a polyvinyl acetal (corresponding to the resin) and a uryl derivative (corresponding to the crosslinking agent) was used. However, the opening size (opening diameter) of the opening 5a whose initial opening size (opening diameter) was 0.5 μm was reduced in the range of 0.07 to 0.23 μm.
[0086]
Next, when dry etching was performed using an etching gas containing a fluorine atom through the opening 5a, as shown in FIG. 6, the polystyrene polymer-containing resist 4 exposed from the opening 5a and the vicinity thereof were etched and removed. 4a was formed. At this time, the opening formed in the layer of the polystyrene polymer-containing resist 4 had a tapered structure. When dry etching was subsequently performed, as shown in FIG. 7, the layer of the PMGI resist 3 exposed from the opening 5a was etched and removed, and the opening 3a was formed. When dry etching was further performed, as shown in FIG. 8, the layer of the PMMA-based resist 2 exposed from the opening 5a was etched and removed. As a result, the openings 5a were sequentially transferred to a multilayer resist including the PMMA-based resist 2, the PMGI 3, and the polystyrene polymer-containing resist 4, and the openings 2a were formed. Part of the formation surface 1 of the fine T-type electrode is exposed from the opening 2a. Then, while the layer of the PMMA-based resist 2 was etched, the polystyrene polymer-containing resist 4 was side-etched, but the PMGI 3 and the PMMA-based resist 2 located thereunder were etched and removed substantially vertically. The opening dimension (opening diameter) of the layer of the PMMA-based resist 2 was 0.21 to 0.37 μm. The above is the lowermost layer opening forming step. The processes shown in FIGS. 5 to 8 are actually performed continuously.
[0087]
Subsequently, in order to form an overgate portion in the fine T-type electrode, the PMGI3 layer as the intermediate layer in the laminated resist is subjected to side etching using a PMGI-soluble solution such as an aqueous solution of tetramethylammonium hydroxide. Was. The amount of side etching of the PMGI3 layer can be easily controlled by adjusting the processing time of the PMGI soluble solution. In this side etching process, since the i-line resist 5 is also dissolved, as shown in FIG. 9, the opening dimension (opening diameter) of the layer of PMGI 3 is changed to the opening of each layer of the PMMA-based resist 2 and the polystyrene polymer-containing resist 4. The shape became larger than the size (opening diameter). The above is the side etching process.
Subsequently, heat treatment was performed to form an opening of the PMMA-based resist 2 into a tapered structure as shown in FIG. The above is the heat treatment step.
[0088]
After that, the resist pattern thickening material 8 is applied to the opening of the PMMA-based resist 2, prebaked, and then crosslinked and baked at a higher temperature than the prebaking to reduce the opening of the i-line resist 5. As a result, as shown in FIG. 11, the opening dimension (opening diameter) of the opening 2a of the PMMA-based resist 2 could be reduced. The above is the lowermost layer opening reduction step.
[0089]
Next, as shown in FIG. 12, the fine T-type electrode 10 was formed by vapor-depositing a metal as an electrode material toward the formation surface 1 of the fine T-type electrode exposed from the opening 2a. At this time, the metal of the electrode material was also deposited on the polystyrene polymer-containing resist 4. Then, when the laminated resist was dissolved and removed by a lift-off method, as shown in FIG. 13, a fine T-type electrode 10 was formed on the formation surface 1 of the fine T-type electrode. The above is the T-type electrode forming step.
[0090]
In the lowermost layer opening reduction step, by adjusting the type, composition, composition ratio, blending amount, concentration, etc. of the resin and the cross-linking agent contained in the resist pattern thickening material, or the resist pattern thickening The thickness of the mixing layer and the degree of crosslinking in the mixing layer can be changed by appropriately changing the application conditions of the coating material or by adjusting the temperature and time of baking performed after application, and As a result, the amount of the resist pattern thickening material to be dissolved and removed can be changed, and the reduction of the opening size (opening diameter) of the opening 2a can be controlled to a desired degree.
Specifically, as the resist pattern thickening material, a material containing 10 to 20% by weight in total of a polyvinyl acetal (corresponding to the resin) and a uryl derivative (corresponding to the cross-linking agent) was used. However, the opening size (opening diameter) of the opening 2a whose initial opening size (opening diameter) was 0.10 to 0.40 μm was reduced to a range of 0.02 to 0.20 μm. As a result, the opening dimension (opening diameter) of the PMMA-based resist 2 for determining the gate length could be formed to about 0.1 μm or less.
[0091]
(Second embodiment)
In the second embodiment, the steps up to the uppermost layer opening reduction step are the same as those in the first embodiment.
Next, in FIG. 5, when ashing was performed by oxygen plasma from the opening 5a of the i-line resist 5, an opening 4a was formed in the polystyrene polymer-containing resist 4 as shown in FIG. Next, the opening 4a was irradiated with ultraviolet light from an excimer xenon lamp. Since PMGI3 has a high solubility in a developing solution when irradiated with ultraviolet light, when irradiated with ultraviolet light and then treated with a PMGI developing solution, an opening 3a is formed in PMGI3 as shown in FIG. Was. Next, when ashing with oxygen plasma was performed through the opening 3a of the PMGI 3, the opening 2a was formed in the PMMA-based resist 2 as shown in FIG. The above is the lowermost layer opening forming step.
In the second embodiment, since the oxygen asher is used for the etching in the lowermost layer opening forming step, the lowermost layer opening can be formed more easily and at lower cost than the dry etching in the first embodiment.
[0092]
Subsequently, when the PMGI3 as the intermediate layer in the laminated resist was subjected to a side etching treatment using a PMGI-soluble solution such as tetramethylammonium hydroxide (NMD-W), as shown in FIG. The opening size (opening diameter) of each layer became larger than the opening size (opening diameter) of each layer of the PMMA-based resist 2 and the polystyrene polymer-containing resist 4. The above is the side etching process.
[0093]
The lowermost layer opening reducing step and the electrode forming step were performed in the same manner as in the first embodiment, and a fine T-type electrode was formed as shown in FIG.
[0094]
(Third form)
In the third embodiment, the heat treatment step was performed in the same manner as in the first embodiment. Then, the opening 2a of the PMMA-based resist 2 was formed into a tapered structure by the heat treatment as shown in FIG.
After the opening 2a of the PMMA-based resist 2 is formed into a tapered structure, the opening 2a of the PMMA-based resist 2 is reduced and the opening size (opening diameter) is reduced as shown in FIG. . The above is the lowermost layer opening reduction step. The heat treatment conditions in the lowermost opening reduction step are different from those in the case where the opening 2a has a tapered structure in the heat treatment step. The amount can be controlled to a desired value.
In the heat treatment in the lowermost layer opening reduction step, when the heat treatment time is 5 to 7 minutes and the heat treatment temperature is 136 to 141 ° C., the amount of reduction of the opening dimension (opening diameter) of the opening 2 a is in the range of more than 0 to 0.2 μm. Was reduced. As a result, the opening dimension (opening diameter) of the PMMA-based resist 2 for determining the gate length could be formed to about 0.1 μm or less.
[0095]
The electrode forming step was performed in the same manner as in the first embodiment, and a fine T-type electrode was formed as shown in FIGS.
[0096]
【Example】
Hereinafter, examples of the present invention will be specifically described, but the present invention is not limited to these examples.
[0097]
(Example 1)
As described below, the laminated resist forming step was performed. That is, as shown in FIG. 1, a PMMA-based resist 2 (ZEP-2000, manufactured by Zeon Corporation) is coated on a GaAs substrate, which is a forming surface 1 of a fine T-type electrode, by a PMGI 3 (MCC) so that the thickness becomes 2600 °. I-line resist 5 (manufactured by Sumitomo Chemical Co., Ltd.) such that the thickness of polystyrene polymer-containing resist 4 (manufactured by Zeon Corporation: ZEP-520) is 2700 mm. : PFI-32) was applied in this order to a thickness of 8500 ° to form a laminated resist.
[0098]
Next, the uppermost layer opening forming step was performed. That is, as shown in FIG. 3, the i-line 6 is selectively exposed to the i-line resist 5 (exposure time 450 msec.) By the photolithography method using the i-line, and as shown in FIG. An opening 5a for forming an electrode was formed. The size of the opening 5a was 0.43 μm.
[0099]
Next, the uppermost layer opening reduction step was performed. First, a resist pattern thickening material was prepared. That is, 16 parts by mass of a polyvinyl acetal resin (KW-3, manufactured by Sekisui Chemical) as the resin, 1 to 1.5 parts by mass of tetramethoxymethyl glycoluril (manufactured by Sekisui Chemical) as the crosslinking agent, 0.06 to 0.3 parts by mass of a polyoxyethylene monoalkyl ether-based surfactant (TN-80, non-ionic surfactant, manufactured by Asahi Denka Co., Ltd.) as a surfactant. As a main solvent component excluding the resin, the cross-linking agent, and the surfactant, a mixed solution of pure water (deionized water) and isopropyl alcohol (mass ratio of pure water (deionized water): isopropyl alcohol = 98.6: 0.4). Next, as shown in FIG. 4, this resist pattern thickening material is applied by a spin coating method at 3000 rpm for 60 seconds, and then pre-baked at 85 ° C. for 70 seconds, and as shown in FIG. On the surface, a mixing layer 7 of the i-line resist 5 and the resist pattern thickening material was formed. Thereafter, a cross-linking bake was performed at 95 ° C. for 70 seconds to cross-link the mixing layer 7. Then, by developing with water for 60 seconds, the resist pattern thickening material other than the crosslinked portion was dissolved and removed. As a result, the opening size of the opening 5a was 0.21 μm, and the opening size of the opening 5a was reduced by 0.22 μm.
[0100]
Next, the lowermost layer opening step was performed. SF from opening 5a ₆ And CHF ₃ Dry etching was performed using a mixed gas of The dry etching conditions were a pressure of 0.5 Pa and an etching film thickness of 1.3 μm. Then, first, as shown in FIG. 6, an opening 4a was formed in the polystyrene polymer-containing resist 4. The opening 4a has a tapered structure. The dry etching was continued to form an opening 3a in the PMGI 3 as shown in FIG. 7, and an opening 2a in the PMMA-based resist 2 as shown in FIG. The opening size of the opening 2a was 0.27 μm.
[0101]
Next, the side etching step was performed. That is, the opening 3a of the PMGI 3 as the intermediate layer in the laminated resist is treated with a tetramethylammonium hydroxide aqueous solution (NMD-W), which is a PMGI-soluble solution, for 40 seconds, and as shown in FIG. Etching was performed. The side etching amount of the opening 3a was 0.20 μm, which was a sufficient amount to facilitate lift-off.
[0102]
Next, the heat treatment step was performed. By subjecting the laminated resist to heat treatment at 138 ° C. for 5 minutes, the opening 2a of the PMMA-based resist 2 was formed into a tapered structure as shown in FIG.
[0103]
Next, the lowermost layer opening reduction step was performed. That is, the resist pattern thickening material used in the uppermost layer opening reduction step is applied at 3000 rpm for 60 seconds to form a mixing layer 8, pre-baked at 85 ° C. for 70 seconds, and then crosslinked at 95 ° C. for 70 seconds. Baking was performed to crosslink the mixing layer 8 in the same manner as in the uppermost layer opening reduction step. Then, by performing development processing for 60 seconds using water, the resist pattern thickening material other than the crosslinked portion was dissolved and removed. As a result, as shown in FIG. 11, the opening 2a was reduced, and the opening size of the opening 2a was 0.11 μm. The reduction amount of the opening size of the opening 2a was 0.16 μm.
[0104]
Next, the electrode forming step was performed. That is, as shown in FIG. ^-7 Electrodes having a thickness of 10 °, a thickness of Pt of 300 °, and a thickness of Au of 5000 ° were formed by vapor deposition using an electron gun heating method or a resistance heating method in a vacuum chamber of Torr or less. Thereafter, the laminated resist was removed by a lift-off method (a method of immersing in a bath solution of N-methyl-2-pyrrolidinone (manufactured by Tokyo Ohka Co., Ltd.) at 75 ° C. for 2 hours), and as shown in FIG. Formed a fine T-type electrode of about 0.1 μm.
Thus, a fine T-type electrode was manufactured.
[0105]
(Example 2)
The steps up to the step of reducing the uppermost layer opening were the same as those in Example 1.
Next, the lowermost layer opening forming step was performed. That is, in FIG. 5, when ashing with oxygen plasma was performed at 300 W for 5 minutes from the opening 5a of the i-line resist 5, the opening 4a was formed in the polystyrene polymer-containing resist 4 as shown in FIG. Next, the opening 4a was irradiated with ultraviolet light from an excimer xenon lamp for 10 seconds. PMGI3 has a high solubility in a developer when irradiated with ultraviolet light. Therefore, after irradiation with ultraviolet light, PMGI3 is treated for 40 seconds using an aqueous solution of tetramethylammonium hydroxide (NMD-W) as a PMGI developer. As shown in FIG. 7, an opening 3a was formed in PMGI3. Next, ashing with oxygen plasma was performed through the opening 3a of the PMGI 3 at 300 W for 5 minutes, so that the opening 2a was formed in the PMMA-based resist 2 as shown in FIG. The opening size of the opening 2a was 0.30 μm.
[0106]
The lowermost opening reduction step and the electrode forming step were performed in the same manner as in the first embodiment, and a fine T-type electrode having a gate length of about 0.1 μm was formed as shown in FIG.
[0107]
(Example 3)
Up to the heat treatment step, the procedure was the same as in Example 1.
Next, the lowermost layer opening reduction step was performed. That is, as shown in FIG. 14, the opening 2a was subjected to a heat treatment at 141 ° C. for 7 minutes to reduce the size of the opening as shown in FIG.
The electrode forming step was performed in the same manner as in the first embodiment, and a fine T-type electrode having a gate length of about 0.1 μm was formed as shown in FIG.
[0108]
(Example 4)
In the fourth embodiment, a fine T-type electrode is formed on a device having a gate recess structure commonly used in FETs, HEMTs and the like by using the method for manufacturing a fine T-type electrode of the present invention.
In Example 1, instead of the GaAs substrate that is the formation surface 1 of the fine T-type electrode, as shown in FIG. 18, InAlAs as the Schottky layer 1a, and InGaAs with a thickness of 300 ° as the cap layer 1b that forms the recess. Are formed in this order to form a fine T-type electrode forming surface 1. Then, the steps up to the step of forming the lowermost layer opening were performed in the same manner as in Example 1.
Next, the heat treatment step was performed at 138 ° C. for 5 minutes, and the opening 2a of the PMMA-based resist 2 was formed into a tapered structure as shown in FIG.
[0109]
Next, when the InGaAs serving as the cap layer 1b was etched from the opening 2a of the PMMA-based resist 2 with a phosphoric acid-based etchant, a gate recess opening 1c was formed as shown in FIG. At this time, assuming that the opening 2a of the PMMA-based resist 2 is about 0.25 μm, the opening dimension of the opening in the gate recess is about 0.30 μm.
[0110]
Next, as shown in FIG. 20, the above-mentioned resist pattern thickening material used in Example 1 was applied to the opening 2a and the opening of the gate recess portion at 3000 rpm for 60 seconds to form a mixing layer 8, Pre-baking was performed at 85 ° C. for 70 seconds, and then crosslinking baking was performed at 95 ° C. for 70 seconds. The mixing layer 8 was cross-linked in the same manner as in the step of reducing the lowermost layer opening of Example 1. Then, the opening 2a of the PMMA-based resist 2 was reduced as shown in FIG. 20 by performing the same processing as the developing processing in Example 1. The size of the opening 2a was about 0.12 μm, and the reduction amount of the opening 2a was 0.19 μm.
[0111]
Next, as shown in FIG. 21, a fine T-type electrode 10 having a gate length of about 0.1 μm was formed in the gate recess in the same manner as in the electrode forming step in Example 1. By the same processing as the lift-off in Example 1, the fine T-type electrode 10 shown in FIG. 22 was formed.
[0112]
Here, the preferred embodiments of the present invention are as follows.
(Supplementary Note 1) A laminated resist forming step of forming a laminated resist including a light-sensitive photoresist layer on at least the uppermost layer on a T-type gate electrode forming surface, and irradiating the laminated resist with light to form the photoresist layer Forming an uppermost opening by patterning only the uppermost opening, and reducing the diameter of the uppermost opening formed in the photoresist layer by applying a resist pattern thickening material to the photoresist layer. An uppermost layer opening reducing step of transferring the uppermost layer opening formed in the photoresist layer to a lower layer of the photoresist layer, penetrating the laminated resist, and forming a lowermost layer opening in the lowermost layer of the laminated resist. Forming a lowermost layer opening, and a lowermost layer opening reducing step of reducing the size of the lowermost layer opening in the lowermost layer of the laminated resist; Forming a T-type electrode in an opening formed through the laminated resist.
(Supplementary Note 2) The lowermost layer opening reduction step is performed by applying a resist pattern thickening material to the surface of the exposed lowermost layer to reduce the diameter of the lowermost layer opening formed in the lowermost layer. 3. The method for producing a fine T-type electrode according to item 1.
(Supplementary Note 3) The production of the fine T-type electrode according to Supplementary Note 1, wherein the lowermost layer opening reduction step is performed by heating the lowermost layer at 136 to 141 ° C., and the lowermost layer is formed of a polymethyl methacrylate-based resist. Method.
(Supplementary Note 4) The method for manufacturing a fine T-type electrode according to any one of Supplementary Notes 1 to 3, wherein the lowermost layer opening forming step is performed by an etching process.
(Supplementary note 5) The method for producing a fine T-type electrode according to supplementary note 4, wherein the etching process is dry etching.
(Supplementary Note 6) The method for manufacturing a fine T-type electrode according to Supplementary Note 4, wherein the etching process includes performing ashing by oxygen plasma.
(Supplementary note 7) The method for manufacturing a fine T-type electrode according to any one of Supplementary notes 1 to 6, wherein the lowermost layer opening forming step includes a heat treatment, and the lowermost layer opening is formed into a tapered structure by the heat treatment.
(Supplementary Note 8) The method for producing a fine T-type electrode according to any one of Supplementary Notes 1 to 7, wherein the laminated resist includes an insulating layer immediately below the photoresist layer.
(Supplementary note 9) The method for producing a fine T-type electrode according to supplementary note 8, wherein the insulating layer is deposited and formed by a plasma CVD method.
(Supplementary Note 10) The method for manufacturing a fine T-type electrode according to any one of Supplementary Notes 1 to 9, wherein the lowermost layer is formed of a material that can be thickened by a resist pattern thickening material.
(Supplementary Note 11) The method of manufacturing a fine T-type electrode according to any one of Supplementary Notes 1 to 10, wherein the lowermost layer is formed of an electron beam resist.
(Supplementary Note 12) The method of manufacturing a fine T-type electrode according to any one of Supplementary Notes 1 to 11, wherein the lowermost layer is formed of a polymethyl methacrylate-based resist.
(Supplementary Note 13) The method for manufacturing a fine T-type electrode according to any one of Supplementary Notes 1 to 12, wherein a layer immediately above the lowermost layer is side-etchable.
(Supplementary Note 14) The method for manufacturing a fine T-type electrode according to any one of Supplementary Notes 1 to 13, wherein the layer immediately above the lowermost layer is formed of a photoresist.
(Supplementary Note 15) The method of manufacturing a fine T-type electrode according to any of Supplementary Notes 1 to 14, wherein the layer immediately above the lowermost layer is formed of a resist containing polydimethylglutarimide as a main component.
(Supplementary Note 16) The method for producing a fine T-type electrode according to any one of Supplementary Notes 1 to 15, wherein a layer immediately below the uppermost layer is formed of an electron beam resist.
(Supplementary Note 17) The method for producing a fine T-type electrode according to any one of Supplementary Notes 1 to 16, wherein a layer immediately below the uppermost layer is formed of a polystyrene polymer-containing resist.
(Supplementary Note 18) The laminated resist is composed of four layers, the lowermost layer is formed of a polymethyl methacrylate-based resist, the layer immediately above the lowermost layer is formed of a resist mainly composed of polydimethylglutarimide, and the upper layer 18. The method for producing a fine T-type electrode according to supplementary notes 1 to 17, wherein is formed of a polystyrene polymer-containing resist, and the uppermost layer is formed of an ultraviolet-sensitive resist.
(Supplementary note 19) The method of manufacturing a fine T-type electrode according to any one of Supplementary notes 1 to 18, wherein the T-type electrode forming step includes removing the laminated resist after forming the T-type electrode by an evaporation method.
(Supplementary Note 20) The method for producing a fine T-type electrode according to supplementary note 19, wherein the removal of the laminated resist is performed by a lift-off method.
(Supplementary Note 21) The method for producing a fine T-type electrode according to any one of Supplementary Notes 1 to 20, wherein the resist pattern thickening material contains a resin, a crosslinking agent, and a surfactant.
(Supplementary note 22) The method for producing a fine T-type electrode according to supplementary note 21, wherein the resist pattern thickening material is soluble in water or alkali.
(Supplementary Note 23) The method for producing a fine T-type electrode according to Supplementary Note 21 or 22, wherein the surfactant is a nonionic surfactant.
(Supplementary note 24) The method for producing a fine T-type electrode according to any one of supplementary notes 21 to 23, wherein the resin is at least one selected from polyvinyl alcohol, polyvinyl acetal, and polyvinyl acetate.
(Supplementary note 25) The method for producing a fine T-type electrode according to any one of Supplementary notes 21 to 24, wherein the crosslinking agent is at least one selected from a melamine derivative, a urea derivative, and a uryl derivative.
(Supplementary Note 26) The method for producing a fine T-type electrode according to any one of Supplementary Notes 21 to 25, comprising at least one selected from a water-soluble aromatic compound and a resin partially having an aromatic compound.
(Supplementary Note 27) The water-soluble aromatic compound is selected from a polyphenol compound, an aromatic carboxylic acid compound, a naphthalene polyhydric alcohol compound, a benzophenone compound, a flavonoid compound, a derivative thereof, and a glycoside thereof. 27. The method for producing a fine T-type electrode according to supplementary note 26, wherein the resin provided in the part is selected from a polyvinyl aryl acetal resin, a polyvinyl aryl ether resin, and a polyvinyl aryl ester resin.
(Supplementary Note 28) The method for producing a fine T-type electrode according to any one of Supplementary Notes 21 to 27, including an organic solvent.
(Supplementary Note 29) The supplementary note 28, wherein the organic solvent is at least one selected from alcohol solvents, chain ester solvents, cyclic ester solvents, ketone solvents, chain ether solvents, and cyclic ether solvents. A method for producing a fine T-shaped electrode according to the above.
(Supplementary Note 30) The method for producing a fine T-type electrode according to any one of Supplementary Notes 21 to 29, wherein a total content of components other than water in the resist pattern thickening material is 1 to 80% by mass.
[0113]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the conventional problem can be solved and the fine T-type electrode which can manufacture a fine T-type electrode at low cost and high throughput without using expensive processes, such as electron beam drawing and SOR light exposure. An electrode manufacturing method can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view for explaining an example of a laminated resist forming step in the method for producing a fine T-type electrode according to the present invention.
FIG. 2 is a schematic explanatory view for explaining another example of a laminated resist forming step in the method for producing a fine T-type electrode according to the present invention.
FIG. 3 is a schematic explanatory view for explaining an example of an uppermost layer opening forming step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 4 is a schematic explanatory view for explaining an example of a state in which an uppermost layer opening is formed by an uppermost layer opening forming step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 5 is a schematic explanatory view for explaining an example of an uppermost layer opening reduction step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 6 is a schematic explanatory view for explaining an example (part 1) of a lowermost layer opening forming step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 7 is a schematic explanatory view for explaining an example (part 2) of a lowermost layer opening forming step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 8 is a schematic explanatory view for explaining an example (part 3) of the lowermost layer opening forming step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 9 is a schematic explanatory view for explaining an example of a side etching step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 10 is a schematic explanatory view for explaining an example of a heat treatment step in the method for producing a fine T-type electrode according to the present invention.
FIG. 11 is a schematic explanatory view for explaining an example of a lowermost layer opening reduction step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 12 is a schematic explanatory view for explaining an example (part 1) of an electrode forming step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 13 is a schematic explanatory view for explaining an example (part 2) of an electrode forming step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 14 is a schematic explanatory view for explaining another example of the heat treatment step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 15 is a schematic explanatory view for explaining another example of the lowermost layer opening reduction step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 16 is a schematic explanatory view for explaining another example (part 1) of an electrode forming step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 17 is a schematic explanatory view for explaining another example (part 2) of the electrode forming step in the method for manufacturing a fine T-type electrode according to the present invention.
FIG. 18 is an example in which a T-type electrode is formed on an element having a gate recess structure, and is a schematic explanatory view for explaining an example of a heat treatment step in the method for manufacturing a fine T-type electrode of the present invention. .
FIG. 19 is an example in which a T-type electrode is formed on an element having a gate recess structure, schematically illustrating a step of forming a gate recess in a method for manufacturing a fine T-type electrode according to the present invention. FIG.
FIG. 20 is an example in which a T-type electrode is formed on an element having a gate recess structure, and is a schematic description for explaining an example of a lowermost layer opening reduction step in the method for manufacturing a fine T-type electrode according to the present invention. FIG.
FIG. 21 is an example in which a T-type electrode is formed on an element having a gate recess structure, for explaining an example (part 1) of an electrode forming step in the method for manufacturing a fine T-type electrode of the present invention. FIG.
FIG. 22 is an example in which a T-type electrode is formed on an element having a gate recess structure, for explaining an example (part 2) of an electrode forming step in the method for manufacturing a fine T-type electrode of the present invention. FIG.
FIG. 23 is a schematic explanatory view for explaining an example of a conventional method for manufacturing a T-type electrode.
FIG. 24 is a schematic explanatory view for explaining another example of a conventional method for manufacturing a T-type electrode.
[Explanation of symbols]
1. Forming surface of fine T-shaped electrode
1a Schottky layer
1b Cap layer
1c Opening (gate recess opening)
2 PMMA resist
2a Opening (lowest layer opening)
3 PMGI
3a opening
4 Resist containing polystyrene polymer
4a opening
5 i-line resist
5a Opening (top layer opening)
6 i-line
7 Mixing layer
8 Mixing layer
9 Electrode material layer
10 Fine T-shaped electrode
11 Lower layer resist
12 opening
14 Upper layer resist
15 Mixing layer
16 UV
18 T-type gate electrode
20 substrates
23 EB exposure resist film
23a second opening
24 Buffer film
25 i-line exposure resist film
25a first opening
26 Third resist film
27 Mixing layer
30 insulating layer

Claims (10)

A laminated resist forming step of forming a laminated resist including a light-sensitive photoresist layer on at least the uppermost layer on the T-type gate electrode formation surface, and irradiating the laminated resist with light to pattern only the photoresist layer. A top layer opening forming step of forming a top layer opening; and a top layer opening for reducing the diameter of the top layer opening formed in the photoresist layer by applying a resist pattern thickening material to the photoresist layer. A reducing step, a lowermost opening for transferring the uppermost opening formed in the photoresist layer to a lower layer of the photoresist layer, penetrating the laminated resist, and forming a lowermost opening in the lowermost layer of the laminated resist; Forming a lowermost opening for reducing the size of the lowermost opening in the lowermost layer of the multilayer resist; Method for producing a fine T-shaped electrode, characterized in that it comprises a T-type electrode forming step of forming a T-shaped electrode in the opening formed through the door. 2. The lowermost layer opening reduction step according to claim 1, wherein the resist pattern thickening material is applied to the surface of the exposed lowermost layer to reduce the diameter of the lowermost layer opening formed in the lowermost layer. A method for manufacturing a fine T-shaped electrode. 3. The method for manufacturing a fine T-type electrode according to claim 1, wherein the lowermost layer opening forming step is performed by an etching process. 4. The method for manufacturing a fine T-type electrode according to claim 1, wherein the lowermost layer opening forming step includes a heat treatment, and the lowermost layer opening has a tapered structure by the heat treatment. 5. The method according to claim 1, wherein the lowermost layer is formed of an electron beam resist. The method for manufacturing a fine T-type electrode according to any one of claims 1 to 5, wherein a layer immediately above the lowermost layer is capable of side etching. 7. The method for manufacturing a fine T-type electrode according to claim 1, wherein a layer immediately above the lowermost layer is formed of a photoresist. 8. The method for manufacturing a fine T-type electrode according to claim 1, wherein the layer immediately below the uppermost layer is formed of an electron beam resist. 9. The method for manufacturing a fine T-type electrode according to claim 1, wherein the resist pattern thickening material contains a resin, a crosslinking agent, and a surfactant. The method for producing a fine T-type electrode according to claim 9, wherein the total content of components other than water in the resist pattern thickening material is 1 to 80% by mass.

Images