JP5661343B2 - Pattern structure manufacturing method - Google Patents

Description

  The present invention relates to a manufacturing method of a pattern structure using a heat-reactive resist material and a mold manufactured using the manufacturing method, and more particularly to a manufacturing method of a fine pattern structure having a large aspect ratio.

  In recent years, with increasing demands for higher density and higher integration in the fields of semiconductors, optical / magnetic recording, etc., a fine pattern processing technique of several hundred nm to several tens of nm or less is essential. Therefore, in order to realize such fine pattern processing, elemental technologies of each process such as a mask / stepper, exposure, resist material and the like are actively studied.

  Many studies are also being conducted on resist materials. Currently, the most common resist material is a photoreactive organic resist (hereinafter also referred to as a photoresist) that reacts with an exposure light source such as ultraviolet light, electron beam, or X-ray (Patent Document 1, Non-Patent Document 1). ).

In the laser light used for exposure, the intensity of the laser light normally focused by a lens shows a Gaussian distribution shape as shown in FIG. At this time, the spot diameter of the laser beam is defined by 1 / e ² . In general, a photoresist reaction is initiated by absorbing energy represented by E = hν (E: energy, h: Planck constant, ν: wavelength). The reaction is therefore not strongly dependent on the light intensity, but rather on the wavelength of the light. For this reason, almost all reaction occurs in the irradiated portion (exposed portion). Therefore, when a photoresist is used, exposure is performed faithfully with respect to the spot diameter.

  The pattern formation method using a photoreactive organic resist is a very effective method for forming a fine pattern of about several hundreds of nanometers. However, since a photoresist using a photoreaction is used, a finer pattern is formed. In order to form, it is necessary to expose with a spot smaller than the pattern required in principle. For this reason, in order to perform exposure with a small spot, it is necessary to use a KrF or ArF laser having a short wavelength as an exposure light source. However, these light source devices such as KrF and ArF lasers are very large and expensive, and are not suitable from the viewpoint of manufacturing cost reduction. In addition, when using an exposure light source such as an electron beam or X-ray having a shorter wavelength, the exposure atmosphere must be in a vacuum state, and a vacuum chamber must be used. There is a limit.

  Therefore, a thermal reaction type resist material is being studied. Unlike a photoresist that uses the above-described photoreaction, this thermally reactive resist material is a resist material that uses a thermal reaction that uses laser light as a heat source. Hereinafter, the principle will be described. Normally, when a laser beam is irradiated onto an object, the temperature of the object has the same Gaussian distribution as the intensity distribution of the laser beam, as shown in FIG. At this time, if a resist that reacts at a certain temperature or higher, that is, a heat-reactive resist is used, the reaction proceeds only at a portion that exceeds a predetermined temperature, so that it is possible to cause a thermal reaction in a range smaller than the laser beam spot diameter. Become. That is, since it becomes possible to form a pattern finer than the spot diameter without shortening the exposure light source wavelength, the influence of the exposure light source wavelength can be reduced by using the heat-reactive resist material. .

  As an example of fine pattern formation using a thermally reactive resist material, in the field of optical recording, WOx, MoOx or other chalcogenide glass (Ag-As-S series) is used as a thermally reactive resist, and a semiconductor laser or a 476 nm laser is used. A technique for forming a fine pattern through thermal reaction by exposure has been reported (Patent Document 2, Non-Patent Document 2). However, the formation of fine patterns using these heat-reactive resists is in response to the demand for narrowing the pattern pitch in the film surface direction, and is not suitable for forming deep grooves in the film thickness direction. Usually, the depth of the groove in the film thickness direction is the same as the depth of the groove in the depth direction as the thickness of the film of the thermal reaction resist. Therefore, in order to form a deep groove, the thickness of the thermal reaction resist is increased. There is a need to. However, the thermal reaction due to exposure of the heat-reactive resist material is isotropic, and as the film thickness increases, the pattern of the heat-reactive resist material increases not only in the depth direction but also in the pattern width in the film surface direction. There was a problem that.

Therefore, as a method of forming a fine pattern with deep grooves in the film thickness direction, a film having a thickness corresponding to a desired groove depth (same as an etching layer) is formed in advance under these thermal reaction type resist material films. In addition, a method of forming a deep groove by etching or the like using a heat-reactive resist material that has been thermally reacted by exposure, developed, and provided with a pattern shape as a mask has been considered. Usually, in order to etch uniformly in the depth direction, a processing method by dry etching is used. As an example, a processing method is used in which SiO ₂ is used as the material of the etching layer and the etching layer is dry-etched with a chlorofluorocarbon gas.

When dry etching is used, the heat-reactive resist material is also exposed to the fluorocarbon gas, so that the heat-reactive resist material used as a mask is required to have resistance to dry etching by the fluorocarbon gas in addition to being capable of fine pattern processing. . Conventionally, WOx, MoOx, and other chalcogenide glasses (Ag—As—S series) have been reported as thermal reaction type resist materials. However, these heat-reactive resists have a problem of low resistance to chlorofluorocarbon gases when dry etching is performed using chlorofluorocarbon gases. For example, even in WOx having relatively high resistance to chlorofluorocarbon gases, the etching selectivity with respect to the etching layer is less than 3 (a value obtained by dividing the etching rate of SiO _{2 by} the etching rate of WOx). As described above, the conventional heat-reactive resist material is insufficient as a heat-reactive resist material for a mask material for forming a deep groove (Non-patent Document 3).

  In addition, when the etching selectivity of the heat-reactive resist material to the etching layer is less than 3, in order to increase the aspect ratio, it is necessary to increase the resist layer according to the thickness of the etching layer. However, the thermal reaction due to the exposure of the heat-reactive resist material is isotropic. By increasing the thickness of the resist layer, the pattern of the heat-reactive resist material is expanded not only in the depth direction but also in the film surface direction. Therefore, it is difficult to form a fine pattern at present. In order to solve this problem, attempts have been made to improve by laminating a heat-reactive resist material on an organic resist (Patent Document 3). In this method, the thermal reaction resist is micropatterned, and the fine pattern is transferred to the organic resist layer by dry etching using oxygen, thereby improving the problem that the etching selectivity of the thermal reaction resist material used is low. ing. However, in the case of dry etching using oxygen, the organic resist layer is isotropically etched, so that the opening width of the fine pattern widens and a dimensional error occurs.

JP 2007-144959 A Japanese Patent No. 4055543 JP 2008-233552 A

Published by Information Technology Corporation “Latest Resist Materials” P.59-P.76 SPIE Vol.3424 (1998) P.20 The 19th Symposium on Phase Change Optical Information Storage (2007) p77

  As described above, when a fine pattern having a high aspect ratio is formed using a heat-reactive resist, the method using the dry etching process has a problem that both etching of the etching layer and etching of the heat-reactive resist material proceed. . For this reason, it is desired to increase the etching selectivity of the etching layer with respect to the heat-reactive resist layer.

  The present invention has been made in view of such points, and an object thereof is to provide a fine pattern structure having a high aspect ratio.

The pattern structure manufacturing method of the present invention includes a step of laminating a transfer layer and a heat-reactive resist layer in order on an etching layer, and a thermal reaction with a predetermined region of the heat-reactive resist layer, followed by a heat reaction. Patterning the thermal reaction resist layer by etching the region, patterning the transfer layer by performing a first dry etching on the transfer layer using the patterned thermal reaction resist layer as a mask, And patterning the etching layer by performing a second dry etching on the etching layer using at least the patterned transfer layer as a mask, and the etching layer, the transfer layer, and the thermal reaction type resist layer are different from each other. The first dry etching and the second dry etching are formed using an inorganic material, and Using different etching gas, as a transfer layer, the second dry etching is formed of a material which is resistant than the thermal reaction type resist layer, as the transfer layer, Co, Zn, Sb, Ni, Nb, said metal group And a material containing at least one of a composite metal of two or more kinds of metals selected from the metal group and an oxide thereof, and Cu, Cu as a heat-reactive resist layer oxide, and a material containing one at least one of two or more kinds of composite metal and its oxide containing Cu, as the gas of the first dry etching, any one of at least CF _4, and SF ₆ And at least CHF ₃ , CH ₂ F ₂ , CxFy (x is an integer of 2 to 4, y is 2x), and C ₃ F as the gas for the second dry etching Any one of ₈ is used .

In the method for producing a pattern structure of the present invention, a step of sequentially laminating a transfer layer and a heat-reactive resist layer on an etching layer, and a heat reaction is performed on a predetermined region of the heat-reactive resist layer, followed by a heat reaction. Patterning the thermal reaction resist layer by etching the region, patterning the transfer layer by performing a first dry etching on the transfer layer using the patterned thermal reaction resist layer as a mask, And patterning the etching layer by performing a second dry etching on the etching layer using at least the patterned transfer layer as a mask, and the etching layer, the transfer layer, and the thermal reaction type resist layer are different from each other. Formed using an inorganic material, the first dry etching and the second dry etching , Using different etching gases from each other, as the transfer layer, the second dry etching is formed of a material which is resistant than the thermal reaction type resist layer, as the transfer layer, Cu, Mo, Sn, Bi , Ga, V, Using a material containing at least one of an oxide of a metal selected from the metal group, a composite metal of two or more metals selected from the metal group , and an oxide thereof, a heat-reactive resist layer as, Ti, Ge, Nb, Sb , Te, W, Pb, oxides of metals selected from the metal group, and among the composite metal and oxides of two or more metals selected from the metal group using a material containing an at least one, as a gas in the first dry etching, at least _{CHF 3, CH 2 F 2,} C x F y (x is integer from 2 to 4, y is 2x), and Using any one of the ₃ F _8, a second dry etching gas, characterized by using any one of at least _CF 4, and SF _6.

In the pattern structure manufacturing method of the present invention, the etching layers are Si, SiO _x1 (x1 is 0 <x1 ≦ 2), and SiN _x2 (x2 is 0 <x2 ≦ 0.75), And TaO _x3 (x3 is 0 <x3 ≦ 0.4).

  In the method for producing a pattern structure of the present invention, it is preferable that a thermal reaction is performed on the heat-reactive resist layer by irradiating the heat-reactive resist layer with laser light.

  In the method for producing a pattern structure of the present invention, it is preferable that the laser beam is irradiated using a semiconductor laser.

  In the method for producing a pattern structure of the present invention, it is preferable that the etching layer, the transfer layer, and the heat-reactive resist layer are formed by sputtering, vapor deposition, or CVD.

  In the pattern structure manufacturing method of the present invention, the etching layer is preferably formed on a substrate having a flat plate shape or a sleeve shape.

  The mold of the present invention is characterized by having a pattern structure having a pattern period of 50 nm to 1000 nm, which is produced by using the above-described method for producing a pattern structure.

  According to the present invention, a transfer layer having an etching selectivity with respect to the etching layer and a thermal reaction resist layer capable of forming a fine pattern by thermal reaction are sequentially laminated on the etching layer to form the thermal reaction resist layer. Since the fine pattern is transferred to the transfer layer and the etching layer is etched using the patterned transfer layer as a mask, a fine pattern structure having a high aspect ratio can be provided.

(A)-(d) is a figure which shows the manufacturing process which shows one Embodiment of the laminated body and mold manufacturing method which concern on this invention. It is a figure which shows the selection ratio by the combination of the thermal reaction type resist layer which concerns on this invention, a transfer layer, an etching layer, and etching gas. It is a figure which shows the selection ratio by the combination of the thermal reaction type resist layer which concerns on this invention, a transfer layer, an etching layer, and etching gas. It is a figure which shows the intensity distribution of a general laser beam. It is a figure which shows the temperature distribution of a general object.

  As a result of intensive studies and experiments conducted by the inventors to solve the above-described problems, even when the heat-reactive resist layer is a material having poor fluorocarbon etching resistance, the present invention is not provided between the etching layer and the heat-reactive resist layer. By providing a transfer layer containing a specific material and forming a fine pattern similar to that of the thermal reaction type resist layer on the transfer layer, the etching selectivity between the transfer layer and the etching layer can be increased, and a high aspect ratio can be obtained. It was discovered that a fine pattern can be formed.

  In addition, some inorganic materials that are highly resistant to chlorofluorocarbon etching cannot be used as a heat-reactive resist because it is difficult to cause a thermal reaction with laser light, but it cannot be used as a heat-reactive resist layer. When the transfer layer is provided as a transfer layer, the same pattern as the heat-reactive resist can be formed on the transfer layer. Therefore, the etching layer can be etched using a material having a high etching resistance as a mask. It was discovered that a pattern can be formed. Hereinafter, a method for manufacturing a pattern structure according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  The pattern structure manufacturing method according to the present embodiment includes a film forming process in which a transfer layer and a heat-reactive resist layer are sequentially stacked on an etching layer, and a thermal reaction with respect to a predetermined region of the heat-reactive resist layer. After that, a resist layer patterning step for patterning the thermal reaction resist layer by etching the thermally reacted region, and a first dry etching is performed on the transfer layer using the patterned thermal reaction resist layer as a mask. A transfer layer patterning step of patterning the transfer layer by etching, and an etching layer patterning step of patterning the etching layer by performing a second dry etching on the etching layer using at least the patterned transfer layer as a mask. And materials used for the thermal reaction type resist layer and the first dry etching As an etching gas used for the second dry etching is characterized by the application of certain materials or gases.

  Specifically, an inorganic material that can be suitably patterned by thermal reaction is used as the thermal reaction type resist layer, and a material that is resistant to the second dry etching as the transfer layer (at least from the thermal reaction type resist layer). The first dry etching and the second dry etching are different fluorocarbon gases. Hereinafter, each step will be described in detail.

<Film formation process>
First, a transfer layer 103 and a thermal reaction type resist layer 104 are sequentially stacked on an etching layer 102 formed on a substrate 101 (see FIG. 1A).

  The material of the substrate 101 is not particularly limited as long as a smooth surface can be secured, and materials such as metal, glass, and silicon wafer can be used. In view of the smoothness of the surface and the low reflection of laser light during exposure, glass is preferred among these. The substrate 101 preferably has a flat plate shape or a sleeve shape.

As a material of the etching layer 102, an etching material used for various dry etchings can be used. Among these etching materials, Si, SiO _x1 (x1 is 0 <x1 ≦ 2) and SiN _x2 (x2) from the viewpoint of improving the aspect ratio by allowing etching to proceed in one direction (anisotropic). Is a material selected from inorganic compounds such as 0 <x2 ≦ 0.75 and TaO _x3 (x3 is 0 <x3 ≦ 0.4). By using these inorganic materials as the etching layer 102 and using a chlorofluorocarbon-based gas as a dry etching gas, it is possible to suppress the opening width of the fine pattern during the dry etching and effectively reduce the dimensional error. It becomes possible. In FIG. 1, when the substrate 101 is etched, the substrate 101 becomes an etching layer.

  In this embodiment, the material of the transfer layer 103 and the heat-reactive resist layer 104 is characterized by the following two combinations.

[Combination 1]
As the material of the thermal reaction type resist layer 104, Cu, Cu oxide, as well as the case of using a material containing an at least one of two or more kinds of composite metal and material selected from the oxide containing Cu, transfer layer 103, Co, Zn, Sb, Ni, Nb, oxides selected from the group of metals, as well as any of at least one material selected from the complex metal and its oxide of a metal selected two or more in the metal group A material containing kagami is used. As used herein, composite metal refers to alloys, eutectics, mixtures, and the like. These combinations are excellent in etching selectivity when the pattern of the heat-reactive resist layer 104 is formed on the transfer layer (see FIG. 3).

[Combination 2]
As the material of the thermal reaction type resist layer 104, Ti, Ge, Nb, Sb, Te, W, Pb, oxides of metals selected from the metal group, and a composite metal and selected two or more in the metal group when using a material containing an at least any one material selected from the oxide, the transfer layer 103 is, Cu, Mo, Sn, Bi , Ga, V, oxides of metals selected from the metal group, and A material containing at least one selected from a composite metal selected from two or more of the metals and an oxide thereof is used. These combinations are excellent in the miniaturization of the pattern formed in the resist layer, and in the case of GeSb and PbO used in the resist layer of Examples described later, 70 nm can be formed by L & S (line and space).

  Further, the film thickness t2 of the transfer layer 103 and the film thickness t3 of the thermal reaction type resist layer 104 are formed to be thinner than the film thickness t1 of the etching layer 102, respectively. The transfer layer 103, the resist layer 104, and the etching layer 102 are formed with a film thickness of about 10 nm to 50 nm, 10 nm to 50 nm, and 300 nm to 1000 nm, respectively, by sputtering, for example.

It is desirable to form a barrier layer between the transfer layer 103 and the heat-reactive resist layer 104 to prevent reaction at the interface between the transfer layer 103 and the heat-reactive resist layer 104 due to heat in the resist layer patterning step described below. . For the barrier layer, Si, SiO _x1 (x1 is 0 <x1 ≦ 2), SiN _x2 (x2 is 0 <x2 ≦ 0.75), TaO _x3 (x3 is 0 <x3 ≦). A material selected from inorganic compounds such as 0.4) can be used. The barrier layer is not particularly limited as long as it is a material that prevents reaction between the thermal resist layer and the transfer layer and particle growth, and can be determined from, for example, a phase diagram.

<Resist layer patterning process>
In the resist layer patterning step, the thermal reaction type resist layer 104 is patterned to form a resist opening 105 and a resist pattern 106 (see FIG. 1B).

  Specifically, after a predetermined region (region where the resist opening 105 is formed) of the thermal reaction type resist layer 104 is thermally reacted, the region subjected to the thermal reaction is etched to thereby form the thermal reaction type resist layer 104. A part of the resist opening 105 is formed by removing a part thereof. The remaining portion of the thermal reaction type resist layer 104 becomes a resist pattern 106.

  The thermal reaction of the thermal reaction type resist layer 104 can be performed by irradiating the thermal reaction type resist layer 104 with light. For example, any light source device used for exposure of a photoreactive photoresist can be used without particular limitation. In order to form a fine pattern, it is preferable to expose with a semiconductor laser. The exposure with laser light may be performed by controlling the irradiation range of laser light and the intensity of laser light so that the region of the resist opening 105 of the thermal reaction type resist layer 104 is equal to or higher than the reaction point of the thermal reaction. It is not necessary to use a laser beam corresponding to the spot diameter and groove width corresponding to the region of the opening 105. For example, even in the condition shown in FIG. 1B where the laser beam hits a region other than the resist opening 105 of the heat-reactive resist layer 104, only the resist opening 105 heats the temperature distribution of the heat-reactive resist layer 104. By controlling the laser beam so as to react, only the resist opening 105 can be thermally reacted. In this embodiment mode, a pattern having an arbitrary shape such as a circle or an ellipse can be formed by changing the intensity of the laser beam during the irradiation of the laser beam.

  Next, etching of the thermal reaction type resist layer 104 in which a predetermined region is thermally reacted will be described. For the etching of the heat-reactive resist layer 104, development conditions used for the photoreactive photoresist can be used. For example, a wet process using a developer can be used. As the developer used in the wet process, an acid, an alkali, or a developer obtained by adding a potential adjusting agent or a surfactant to them can be used. By this etching process, the thermal reaction region of the thermal reaction type resist layer 104 is dissolved and removed (or other than the thermal reaction region is dissolved and removed), and the resist opening 105 and the resist pattern 106 are formed.

<Transfer layer patterning process>
In the transfer layer patterning step, the transfer pattern 107 is formed by patterning the transfer layer 103 by dry etching using an etching gas having a predetermined composition using the patterned thermal reaction resist layer 104 (resist pattern 106) as a mask. (See FIG. 1C).

  In the dry etching in the transfer layer patterning step, the type of etching gas used for each group of combinations of the material of the transfer layer 103 and the thermal reaction type resist layer 104 is appropriately selected.

In the case of the combination 1, an etching gas containing at least one of CF ₄ and SF ₆ is used as an etching gas.

In the case of the combination 2, an etching gas containing at least one of CHF ₃ , CH ₂ F ₂ , C _x F _y (x is an integer of 2 to 4, y is 2x), and C ₃ F ₈ as an etching gas. Is used. Among these etching gases, it is preferable to use an etching gas containing at least one of C ₂ F ₆ , C ₃ F ₆ , C ₄ F ₈ , and C ₃ F ₈ .

<Etching layer patterning process>
In the etching layer patterning step, an etching pattern 108 is formed by patterning the etching layer 102 by dry etching using an etching gas having a predetermined composition using at least the patterned transfer layer 104 (transfer pattern 107) as a mask. (See FIG. 1 (d)). If the resist pattern 106 remains after dry etching in the transfer layer patterning step, the resist pattern 106 can also be used as a mask. Conversely, when the resist pattern 106 remains after dry etching in the transfer layer patterning step, the resist pattern 106 may be selectively removed.

  In dry etching in the etching layer patterning step, the type of etching gas used for each group of combinations of the material of the transfer layer 103 and the resist layer 104 is appropriately selected.

In the case of the combination 1, an etching gas containing at least one of CHF ₃ , CH ₂ F ₂ , C _x F _y (x is an integer from 2 to 4, y is 2x), and C ₃ F ₈ as an etching gas. Is used. Among these etching gases, it is preferable to use an etching gas containing at least one of C ₂ F ₆ , C ₃ F ₆ , C ₄ F ₈ , and C ₃ F ₈ .

In the case of the combination 2, an etching gas containing at least one of CF ₄ and SF ₆ is used as an etching gas.

  After the etching pattern 108 is formed, the pattern structure can be manufactured by removing the transfer pattern 107 (and the resist pattern 106) used as a mask. As shown in this embodiment mode, the transfer layer 103 made of a combination of specific materials and the thermal reaction type resist layer 104 are stacked on the etching layer 108 and patterned by different methods, whereby the etching layer 102 is obtained. A mask (transfer pattern 107) having a fine pattern and a high etching selectivity with respect to the etching layer 102 can be provided thereon. By patterning the etching layer 102 using this mask, a fine pattern structure with a high aspect ratio can be manufactured.

In addition, in the dry etching of the transfer layer patterning step and the etching layer patterning step according to the present embodiment, different gases may be contained as long as they satisfy the types and compositions of the above etching gases, such as Ar. It is preferable to contain an inert gas and O ₂ and H ₂ . When such a dry etching gas is used, the Ar ion in the plasma collides with the chlorofluorocarbon gas during the etching, so that the degree of dissociation of the chlorofluorocarbon gas changes and the fluorocarbon film serving as a protective layer against dry etching is changed. Since the deposition amount and the amount of fluorine radicals that etch the etching layer 102, the transfer layer 103, and the thermal reaction type resist layer 104 change, the etching rate (etching rate) of the etching layer 102, the transfer layer 103, and the resist layer 104 is increased or decreased. This is preferable.

As the additive gas mixed with the etching gas, N ₂ , He, Ne, Kr, Xe, or the like can be used in addition to the above-described Ar, O ₂ , H ₂ . Among these additive gases, Ar, N ₂ , O ₂ , and H ₂ are preferable from the viewpoint of adjusting the etching rate.

As a combination of etching gas and additive gas, CF ₄ + Ar, C ₂ F ₄ + Ar, C ₃ F ₆ + Ar, C ₄ F ₈ + Ar, C ₃ F ₈ + Ar, CHF ₃ + Ar, CH ₂ F ₂ + Ar, SF ₆ + Ar , CF ₄ + N ₂ , C ₂ F ₄ + N ₂ , C ₃ F ₆ + N ₂ , C ₄ F ₈ + N ₂ , C ₃ F ₈ + N ₂ , CHF ₃ + N ₂ , CH ₂ F ₂ + N ₂ , SF ₆ + N ₂ , CF ₄ + O ₂ , C ₂ F ₄ + O ₂ , C ₃ F ₆ + O ₂ , C ₄ F ₈ + O ₂ , C ₃ F ₈ + O ₂ , CHF ₃ + O ₂ , CH ₂ F ₂ + O ₂ , SF ₆ + O ₂ , CF ₄ + H ₂ , C ₂ F ₄ + H ₂ , C ₃ F ₆ + H ₂ , C ₄ F ₈ + H ₂ , C ₃ F ₈ + H ₂ , CHF ₃ + H ₂ , CH ₂ F ₂ + H ₂ , SF ₆ + H ₂ Is preferred.

  Next, the present invention will be described in detail with reference to examples carried out to clarify the effects of the present invention. In addition, this invention is not limited at all by the following examples.

[Selection ratio measurement method]
In this embodiment, the etching rate is measured by partially forming a dry etching mask on each of the heat-reactive resist layer, the transfer layer, and the etching layer. The etching time is 10 to 20 minutes, the processing pressure is 1 to 5 Pa, After performing dry etching under the same conditions in the range of electric power of 100 W to 500 W and gas flow rate of 10 sccm to 100 sccm, the mask is removed, and the step formed by the mask portion and the non-mask portion is measured by a step gauge (KLA -It measured by measuring by Alpha-StepIQ made by Tencor. The etching selectivity ratio of the thermal reaction type resist layer to the transfer layer is a value represented by the etching rate of the thermal reaction type resist layer / the etching rate of the transfer layer, and the etching selectivity ratio of the transfer layer to the etching layer is the etching rate of the etching layer / A numerical value represented by the etching rate of the transfer layer was used. As a dry etching mask in measuring the selectivity, a mask made of a photoresist or Kapton tape can be used.

[Relationship between selection ratio and aspect ratio]
The selection ratio and aspect ratio have the following relationship. The aspect ratio is defined as B / A, where A is the fine pattern opening width and B is the fine pattern depth. For example, in the case of a layer structure such as a heat-reactive resist layer and an etching layer, when the opening width of the fine pattern of the heat-reactive resist layer is about 100 nm, the selectivity ratio between the heat-reactive resist layer and the etching layer is 10, When the film thickness of the thermal reaction type resist layer is 40 nm, the depth of the etching layer that can be dry-etched is 400 nm. In this case, the aspect ratio is 4. If the selection ratio is 50, the aspect ratio is 20. As described above, the higher the selection ratio between the thermal reaction type resist layer and the etching layer, the higher the aspect ratio fine pattern can be formed.

[Production Example 1]
In FIG. 1, a GeSb target is selected as the material for the thermal reaction type resist layer 104, and a CuO target is selected as the material for the transfer layer 103. A SiO ₂ target was selected as the etching layer 102. The CuO selected here may have a composition containing 10 to 20% at of other elements.

First, a 300 nm etching layer 102 was formed on a 50 mmφ glass flat substrate 101 by a sputtering method using a SiO ₂ target. Subsequently, using a CuO, SiO ₂ , and GeSb target, a transfer layer 103 was formed to a thickness of 40 nm, a barrier layer was formed to 20 nm, and a thermal reaction type resist layer 104 was formed to a thickness of 40 nm (see FIG. 1A).

  The heat-reactive resist layer 104 formed as described above was exposed under the following conditions.

Semiconductor laser wavelength for exposure: 405 nm
Lens numerical aperture: 0.85
Exposure laser power: 1mW ~ 10mW
Feed pitch: 150 nm to 350 nm

  Various shapes and patterns can be produced by modulating the intensity of the laser beam while irradiating the heat-reactive resist layer 104 with the laser beam, but in the experiment, a continuous groove shape was used as a pattern to confirm the accuracy of the thermal reaction. It was used. The patterning shape of the heat-reactive resist layer 104 may be an isolated circular shape, an elliptical shape, or the like depending on the intended application, and is not limited at all.

  Subsequently, development of the heat-reactive resist that had been subjected to a heat reaction in a predetermined region was performed by the exposure machine (see FIG. 1B). Development by wet process was applied. As the developer, an acid, an alkali, or a material obtained by adding a potential adjusting agent or a surfactant to them can be used.

Next, by performing dry etching using the resist pattern 106 of the thermal reaction type resist layer 104 as a mask, a transfer pattern 107 was formed on the transfer layer 103 as shown in FIG. In dry etching, CHF ₃ was used as an etching gas, dry etching was performed under conditions of a processing gas pressure of 5 Pa, a processing power of 300 W, and a processing time of 10 minutes.

Finally, the etching layer 102 was dry etched to form an etching pattern 108. Etching was performed using SF ₆ or CF ₄ as an etching gas under conditions of a processing gas pressure of 5 Pa, a processing power of 300 W, and a processing time of 10 minutes. A shape as shown in FIG. 1D is obtained after the dry etching. In this case, since the selection ratio between the transfer layer 103 and the etching layer 102 is larger than the selection ratio between the thermal reaction type resist layer 104 and the etching layer 102, a fine pattern with a high aspect ratio can be easily obtained.

  FIG. 2 shows the etching rate of the thermal reaction type resist layer 104, the transfer layer 103, and the etching layer 102, the etching selectivity of the thermal reaction type resist layer 104 with respect to the transfer layer 103, and the etching of the transfer layer 103 with respect to the etching layer 102. The selectivity is shown. FIG. 2 shows a case where BiSn and CuV are used as the transfer layer 103 in addition to CuO as compared with the case where GeSb is used as the thermal reaction type resist layer 104 (see FIGS. 2A to 2C). .

In order to reduce etching size and shape errors, it is preferable that the respective selection ratios are high. The combination of the thermal reaction type resist layer 104 and the transfer layer 103 is GeSb / CuO, GeSb / BiSn, or GeSb / CuV, but GeSb / BiSn having a high selectivity between the transfer layer 103 and the etching layer 102 is more preferable. BiSn uses SF ₆ or CF ₄ as the etching gas, the processing gas pressure is 5 Pa, the processing power is 300 W, and the processing time is 10 minutes. When dry etching is performed, the transfer layer 103 is not etched and the fluorocarbon film is formed. Since the film is deposited, the selection ratio becomes very large, and a fine pattern with a high aspect ratio can be easily obtained. Here, the selectivity is calculated with an etching rate of 0.1.

As an example in which the transfer pattern 107 is easily formed on the transfer layer 103, a combination of GeSb / CuO can be given. When the etching gas is CHF ₃ , the processing gas pressure is 5 Pa, the processing power is 300 W, and the processing time is 10 minutes, the transfer pattern 107 is formed with a selection ratio of 4.2 between the thermal reaction type resist layer 104 and the transfer layer 103. In the etching layer patterning process for forming the etching pattern 108, when the etching gas is SF ₆ , the processing gas pressure is 5 Pa, the processing power is 300 W, and the processing time is 10 minutes, the transfer layer 103, the etching is performed. The selection ratio of the layer 102 is about 49. If the transfer layer 103 has a thickness of 40 nm, SiO ₂ can be etched by 3.5 μm or more. When the opening width of the etching pattern 7 is 100 nm, the aspect ratio is 35. The material described in this production example is the composition of the target.

[Production Example 2]
In FIG. 1, a PbO target was selected as the material for the thermal reaction type resist layer 104, and a CuO target was selected as the material for the transfer layer 103. A SiO ₂ target was selected as the etching layer 102. The CuO selected here may have a composition containing 10% to 20% of other elements.

First, a 300 nm etching layer 102 was formed on a 50 mmφ glass flat substrate 101 by a sputtering method using a SiO ₂ target. Subsequently, using a CuO and PbO target, a transfer layer 103 was formed to a thickness of 40 nm and a thermal reaction type resist layer 104 was formed to a thickness of 20 nm (FIG. 1A). The steps of exposure and development are the same as in Example 1.

Next, by performing dry etching using the resist pattern 106 of the thermal reaction type resist layer 104 as a mask, a transfer pattern 107 was formed on the transfer layer 103 as shown in FIG. In dry etching, C ₄ F ₈ was used as an etching gas, dry etching was performed under the conditions of a processing gas pressure of 5 Pa, a processing power of 300 W, and a processing time of 5 minutes. The C ₄ F ₈ gas used here may contain an additive gas.

Finally, the etching layer 102 was dry etched to form an etching pattern 108. Etching was performed using SF ₆ or CF ₄ as an etching gas under conditions of a processing gas pressure of 5 Pa, a processing power of 300 W, and a processing time of 10 minutes. A shape as shown in FIG. 1D is obtained after the dry etching. In this case, since the selection ratio between the transfer layer 103 and the etching layer 102 is larger than the selection ratio between the thermal reaction type resist layer 104 and the etching layer 102, a fine pattern with a high aspect ratio can be easily obtained.

  2 shows the etching rate of the thermal reaction type resist layer 104, the transfer layer 103, and the etching layer 102, the selection ratio of the etching of the thermal reaction type resist layer 104 to the transfer layer 103, and the etching rate of the transfer layer 103 relative to the etching layer 102. The selectivity is shown. Note that FIG. 2 shows a case where CuO is used as the transfer layer 103 in contrast to the case where PbO is the heat-reactive resist layer 104 (see FIG. 2D).

In the case of a combination of PbO / CuO, the transfer pattern 107 to the transfer layer 103 is easily formed. When the etching gas is C ₄ F ₈ , the processing gas pressure is 5 Pa, the processing power is 300 W, and the processing time is 5 minutes, the selection ratio of the thermal reaction type resist layer 104 and the transfer layer 103 is 10, and the transfer pattern 107 is formed. In the etching layer patterning process for forming the etching pattern 108, when the etching gas is SF ₆ , the processing gas pressure is 5 Pa, the processing power is 300 W, and the processing time is 10 minutes, the transfer layer 103, the etching is performed. The selection ratio of the layer 102 is about 49. If the transfer layer 103 has a thickness of 40 nm, SiO ₂ can be etched by 3.5 μm or more. When the opening width of the etching pattern 7 is 100 nm, the aspect ratio is 35. The material described in this production example is the composition of the target.

[Production Example 3]
A CuO target was selected as the heat-reactive resist layer 104, and a Co ₃ O ₄ target was selected as the material of the transfer layer 103. A SiO ₂ target was selected as the etching layer 102. (CuO selected here may have a composition containing 10 to 20% at least of other elements)

First, a 300 nm etching layer 102 was formed on a 50 mmφ glass flat substrate 101 by a sputtering method using a SiO ₂ target. Subsequently, using a Co ₃ O ₄ , SiO ₂ , and CuO target, a transfer layer 103 was deposited to a thickness of 20 nm, a barrier layer was deposited to 20 nm, and a thermal reaction type resist layer 104 was deposited to a thickness of 40 nm (FIG. 1A). The steps of exposure and development are the same as in Example 1.

Next, as shown in FIG. 1B, by performing dry etching using the resist pattern 106 of the thermal reaction type resist layer 104 as a mask, a transfer pattern 107 is formed on the transfer layer 103 as shown in FIG. 1C. To do. In dry etching, CF ₄ was used as an etching gas, dry etching was performed under conditions of a processing gas pressure of 5 Pa, a processing power of 300 W, and a processing time of 10 minutes.

Finally, the etching layer 102 was dry etched to form an etching pattern 108. Etching was performed using CHF ₃ as an etching gas under conditions of a processing gas pressure of 5 Pa, a processing power of 300 W, and a processing time of 10 minutes. A shape as shown in FIG. 1D is obtained after the dry etching. In this case, since the fluorocarbon film is deposited without etching the transfer layer 103, the selection ratio becomes very large, and a fine pattern with a high aspect ratio can be easily obtained. Here, the selectivity is calculated with an etching rate of 0.1.

FIG. 3 shows the etching rate of the thermal reaction type resist layer 104, the transfer layer 103, and the etching layer 102, the etching selectivity ratio of the thermal reaction type resist layer 104 to the transfer layer 103, and the etching rate of the transfer layer 103 relative to the etching layer 102. The selectivity is shown. FIG. 3 shows a case where ZnSb and NiNb are used as the transfer layer 103 in addition to Co ₃ O ₄ as compared with the case where CuO is used as the thermal reaction type resist layer 104 (FIGS. 3A to 3). c)).

In order to reduce etching size and shape errors, it is preferable that the respective selection ratios are high. The combination of the thermal reaction type resist layer 104 and the transfer layer 103 is CuO / Co ₃ O ₄ , CuO / ZnSb, CuO / NiNb, but CuO / Co ₃ O ₄ having a high selectivity between the transfer layer 103 and the etching layer 102, CuO / NiNb is more preferable. Co ₃ O ₄ and NiNb use CHF ₃ as an etching gas, a processing gas pressure of 5 Pa, a processing power of 300 W, and a dry processing time of 10 minutes, the transfer layer 103 is not etched and the fluorocarbon film is not etched. Therefore, the selection ratio becomes very large, and a fine pattern with a high aspect ratio can be easily obtained. Here, the selectivity is calculated with an etching rate of 0.1.

As an example in which the transfer pattern 107 is easily formed on the transfer layer 103, a combination of CuO / ZnSb can be given. When the etching gas is SF ₆ , the processing gas pressure is 5 Pa, the processing power is 300 W, and the processing time is 10 minutes, the selection ratio of the thermal reaction type resist layer 104 and the transfer layer 103 is 9.8, and the transfer pattern 107 is formed. In the etching layer patterning process for forming the etching pattern 108, when the etching gas is CHF ₃ , the processing gas pressure is 5 Pa, the processing power is 300 W, and the processing time is 10 minutes, the transfer layer 103, the etching is performed. The selection ratio of the layer 102 is about 49. If the transfer layer 103 has a thickness of 40 nm, SiO ₂ can be etched by 1.9 μm or more. When the opening width of the etching pattern 108 is 100 nm, the aspect ratio is 19. The material described in this production example is the composition of the target.

  The method for producing a pattern structure of the present invention is suitably used as a method for producing a structure having a fine structure such as a mold.

DESCRIPTION OF SYMBOLS 101 Substrate 102 Etching layer 103 Transfer layer 104 Thermal reaction type resist layer 105 Resist opening 106 Resist pattern 107 Transfer pattern 108 Etching pattern

Claims (8)

Laminating a transfer layer and a heat-reactive resist layer in order on the etching layer;
Patterning the thermally-reactive resist layer by performing a thermal reaction on a predetermined region of the thermally-reactive resist layer and then etching the thermally-reacted region; and
Patterning the transfer layer by applying a first dry etching to the transfer layer using the patterned thermal reaction resist layer as a mask;
Patterning the etching layer by performing a second dry etching on the etching layer using at least the patterned transfer layer as a mask, and
The etching layer, the transfer layer, and the thermal reaction type resist layer are formed using different inorganic materials,
Different etching gases are used as the first dry etching and the second dry etching,
The transfer layer is formed of a material that is more resistant to the second dry etching than the thermal reaction type resist layer ,
As the transfer layer, at least one of Co, Zn, Sb, Ni, Nb, an oxide selected from the metal group, a composite metal of two or more metals selected from the metal group, and an oxide thereof Using a material containing
As the heat-reactive resist layer, a material containing at least one of Cu, Cu oxide, two or more kinds of composite metals containing Cu, and oxides thereof is used.
As the gas for the first dry etching, at least one of CF ₄ and SF ₆ is used,
As the second dry etching gas, at least one of CHF ₃ , CH ₂ F ₂ , CxFy (x is an integer of 2 to 4, y is 2x), and C ₃ F ₈ is used. A manufacturing method of a pattern structure. Laminating a transfer layer and a heat-reactive resist layer in order on the etching layer;
Patterning the thermally-reactive resist layer by performing a thermal reaction on a predetermined region of the thermally-reactive resist layer and then etching the thermally-reacted region; and
Patterning the transfer layer by applying a first dry etching to the transfer layer using the patterned thermal reaction resist layer as a mask;
Patterning the etching layer by performing a second dry etching on the etching layer using at least the patterned transfer layer as a mask, and
The etching layer, the transfer layer, and the thermal reaction type resist layer are formed using different inorganic materials,
Different etching gases are used as the first dry etching and the second dry etching,
The transfer layer is formed of a material that is more resistant to the second dry etching than the thermal reaction type resist layer,
As the transfer layer, Cu, Mo, Sn, Bi , Ga, V, oxides of metals selected from the metal group, and the complex metal and its oxides of two or more metals selected from the metal group Use a material containing at least one of them,
As the thermal reaction type resist layer, Ti, Ge, Nb, Sb , Te, W, Pb, oxides of metals selected from the metal group, and a composite metal of two or more metals selected from the metal group And a material containing at least one of the oxides thereof,
As the gas for the first dry etching, at least one of CHF ₃ , CH ₂ F ₂ , C _x F _y (x is an integer of 2 to 4, y is 2x), and C ₃ F ₈ is used.
Wherein the second dry etching gas, at least CF _4, and a manufacturing method of the characteristics and to Rupa turn structure the use of any one of SF _6. The etch layer is, _{Si, SiO} x1 (x1 is 0 <x1 ≦ 2.) And _SiN x2 (x2 is 0 <x2 ≦ 0.75.), And TaO _x3 (x3 is 0 < a x3 ≦ 0.4 is.) the method of producing a pattern structure according to claim 1 or claim 2, characterized in that it is selected from. By irradiating a laser beam to the heat reaction type resist layer, producing a pattern structure according to any one of claims 1 to 3, characterized by performing thermal reaction against the thermal reaction type resist layer Method. The pattern structure manufacturing method according to claim 4 , wherein the laser light irradiation is performed using a semiconductor laser. The etching layer, the transfer layer and the thermal reaction type resist layer, a sputtering method, a pattern structure as claimed in any one of claims 5, characterized in that the deposited using vapor deposition or CVD Production method. Method of manufacturing a patterned structure according to any one of claims 1 to claim 6, said etching layer, and forming on a substrate having a plate shape or a sleeve shape. A mold having a pattern structure with a pattern period of 50 nm to 1000 nm, produced using the method for producing a pattern structure according to any one of claims 1 to 7 .

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