JP4826397B2 - Pattern structure and pattern forming method - Google Patents

Description

  The present invention relates to a pattern structure formed by using a photolithography technique and a pattern forming method.

  In the manufacturing process of various electronic components including a semiconductor device, a resist pattern formed by using a photolithography technique which is one of fine processing techniques is widely used. In the field of MEMS (Micro-Electro-Mechanical System) and the like, formation of a resist pattern having a higher aspect ratio is required, but pattern peeling and falling after development are serious problems.

  6A to 6D are process cross-sectional views illustrating a conventional method for forming a resist pattern. An adhesive layer 52 that enhances adhesion to a resist material is formed on a substrate 51 made of semiconductor silicon, glass, or the like, and then a resist material 53 is applied. As the adhesion layer 52, a coating film of HMDS (hexamethyldisilazane) that makes the surface of the substrate 51 hydrophobic is widely used. Then, the resist material 53 is exposed using the mask 54 and then subjected to development processing, whereby a resist pattern 55 corresponding to the mask pattern is formed on the substrate 51.

  However, when the resist pattern 55 is fine and has a high aspect ratio, there is a problem that the pattern peels off and disappears or falls or undulates as shown in the figure. This is considered to be caused by the fact that the resist pattern is fine and has a high aspect ratio shape, so that the adhesion with the substrate 51 is lowered and peeling occurs.

  In order to solve this problem, as the photosensitive resin composition, an amine-based material is selected for the main chain of the base resin (see Patent Document 1 below), or a carbon film is sputtered on the substrate and then subjected to chemical treatment. (See Patent Document 2 below). In addition, a method of rinsing and drying with a rinse solution degassed under reduced pressure before dropping the rinse on the substrate after development (see Patent Document 3 below), and forming a fluorine-containing polymer layer before applying the photosensitive material Method (see Patent Document 4 below), rinsing of a resist pattern after development using a rinsing liquid for lithography that contains water and an ethyleneoxy group and contains a nonionic surfactant so as not to break fluorine atoms A method (see Patent Document 5 below) has been proposed.

JP-A-6-202329 Japanese Patent Laid-Open No. 7-191467 JP-A-9-246156 JP 2002-198283 A JP 2004-184648 A

  However, any of the above-mentioned methods is not sufficient as a countermeasure in terms of pattern flow and peeling, and particularly a problem remains in forming a fine and high aspect ratio pattern on glass or film. It was.

  This invention is made | formed in view of the above-mentioned problem, and makes it a subject to provide the pattern structure which can form the resist pattern of a fine and high aspect ratio with respect to glass or a film, and a pattern formation method.

  In solving the above problems, the pattern structure of the present invention comprises a substrate, a base layer made of a photosensitive resist material formed on the substrate, and a photosensitive resist material patterned on the base layer. And a pattern layer.

  The pattern forming method of the present invention is a pattern forming method in which a photosensitive resist material is applied on a substrate, and a resist pattern is formed through at least exposure and development steps, and the photosensitive resist material is formed on the substrate. Before the step of coating the substrate, there is a step of forming a base layer made of the same or other photosensitive resist material on the substrate.

  In the present invention, by providing a base layer made of a photosensitive material as the base of the pattern layer, the adhesion between the substrate and the pattern layer is improved, and a fine and high aspect ratio pattern layer can be formed. Moreover, in order to improve the adhesiveness between a board | substrate and a base layer, it is preferable to interpose the contact bonding layer which consists of HMDS (hexamethyldisilazane), for example.

  The photosensitive resist material used for the underlayer may be different from the photosensitive resist material constituting the pattern layer, but the affinity, compatibility, and adhesion to the pattern layer can be obtained by using the same type of photosensitive resist material. Therefore, it is possible to stably form a fine and high aspect ratio pattern layer. The sensitive light source of the photosensitive resist material is not particularly limited, and various resist materials that are cured by ultraviolet rays, infrared rays, electron beams, and the like can be used.

  The pattern structure configured as described above may constitute the final structure, or the pattern structure may be thinned by peeling the resist pattern from the substrate. Examples of application of the pattern structure according to the present invention include, for example, microchannel devices for DNA chips, optical devices such as optical waveguides, viewing angle control elements utilizing the transparency and scattering properties of liquid crystal materials, and the like. Of course, it is not limited to these.

  As described above, according to the present embodiment, since the base layer made of a photosensitive material is provided on the base layer of the pattern layer, the adhesion between the substrate and the pattern layer is improved, and the pattern layer of a fine and high aspect ratio is formed. Formation is possible.

  Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to the following embodiments, and various modifications can be made based on the technical idea of the present invention.

(First embodiment)
1A to 1E are schematic process cross-sectional views illustrating a pattern forming method according to a first embodiment of the present invention. First, as shown in FIG. 1A, a substrate 11 on which a pattern layer is to be formed is prepared. The substrate 11 is made of a transparent substrate such as glass, a polymer film, or a polymer film containing an inorganic filler, but other than this, a semiconductor substrate such as a silicon substrate may be used.

  Next, as shown in FIG. 1B, an adhesion layer 12 is formed on the surface of the substrate 11. The adhesion layer 12 is for enhancing adhesion between the substrate 11 and the photosensitive resist material. Examples of the constituent material of the adhesion layer 12 include, but are not limited to, HMDS (hexamethyldisilazane). The adhesion layer 12 is formed by applying HMDS to the surface of the substrate 11.

  Next, as shown in FIG. 1C, a base layer 13 </ b> A made of a photosensitive resist material is formed on the adhesion layer 12. In the present embodiment, as a method for forming the base layer 13 </ b> A, in addition to applying a liquid resist material, a dry film resist material may be laminated on the substrate 11. The base layer 13A is cured by overall exposure after coating. In the present embodiment, the base layer 13A is made of a resist material that is exposed to ultraviolet rays.

  The formation thickness of the underlayer 13A is not particularly limited, but if it is too thick, peeling or cracking is likely to occur due to internal stress of the underlayer, and if it is too thin, the adhesion of the pattern layer tends to be reduced. Although it depends on the device to be used, the formation thickness of the base layer 13A is preferably 1 to 100 μm, more preferably 5 to 30 μm.

  As a specific method of forming the underlayer 13A, a resist material (for example, “SU-8” manufactured by Kayaku Microchem Co., Ltd.) is spin-coated at 3000 rpm × 30 seconds, and 65 ° C. × 5 minutes and 95 ° C. × 30 minutes. By baking under conditions, an underlayer having a thickness of 20 μm can be formed. When forming a base layer on a flexible substrate such as a film or a large substrate, a slit die coater or the like can be used in addition to the spin coater. Note that the above formation conditions are examples, and can be appropriately changed according to specifications and the like.

  Subsequently, as shown in FIG. 1D, a resist layer 13B is formed on the base layer 13A, and the resist layer 13B is dried and then exposed through a mask. Thereafter, as shown in FIG. 1E, the exposed resist layer 13B is developed to form a pattern layer 15 corresponding to the pattern shape of the mask.

  The resist layer 13B is made of the same type of photosensitive resist material as that of the base layer 13A, but a different kind of resist material may be used. By using the same type of photosensitive resist material, the affinity, compatibility, and adhesion to the pattern layer are improved, and a fine and high aspect ratio pattern layer can be stably formed.

  In the present embodiment, as the resist layer 13B, a negative photosensitive resist material in which an exposed portion is cured and remains is used. Among these, by using a chemically amplified resist material (for example, “SU-8” manufactured by Kayaku Microchem Corporation), the fine and high aspect ratio pattern layer 15 can be accurately formed.

  Next, a specific method for forming the pattern layer 15 will be described with reference to FIG. A resist layer 13B is formed on the base layer 13A by spin coating. The thickness of the resist layer can be appropriately determined depending on the device to be used, but if it is too thick like the underlayer, peeling and cracks are likely to be formed. Examples of methods for preventing these include a method of applying the resist layer in a plurality of times, and devising an ascending / descending speed in the drying process.

  “SU-8” manufactured by Kayaku Microchem Corporation is used as a constituent material of the resist layer 13B, and this is formed with a profile of 1000 rpm × 5 seconds, 1200 rpm × 10 seconds, and 1500 rpm × 60 seconds. The above operation is performed three times to obtain a resist layer 13B having a thickness of 150 μm. Next, the resist layer 13B is soft baked under conditions of 65 ° C. × 5 minutes and 95 ° C. × 30 minutes. Thereafter, i-line exposure is performed, post-exposure baking (PEB) is performed, and then development processing is performed by a dipping method. If necessary, the formed resist pattern is hard baked. As described above, the pattern layer 15 can be formed on the base layer 13A. Note that the above formation conditions are examples, and can be appropriately changed according to specifications and the like.

  As described above, the pattern structure 10 in which the pattern layer 15 on the substrate 11 is formed is manufactured. According to this embodiment, since there is a step of forming the base layer 13A on the substrate 11 before the step of applying and forming the resist layer 13B, the adhesion of the pattern layer 15 to the base layer 13A is enhanced. Further, it is possible to prevent pattern defects such as disappearance or collapse due to pattern peeling during development. Accordingly, the adhesion of the pattern layer 15 to the substrate 11 is improved, and the fine and high aspect ratio pattern layer 15 can be formed with high accuracy.

  The shape of the pattern layer 15 may be a stripe shape, a lattice shape, a honeycomb shape, or the like, or a shape having a pattern density in each region. Further, the formed base layer 13A and pattern layer 15 may have a light-transmitting property or may not have a light-transmitting property. Furthermore, it is also possible to peel off the produced pattern layer 15 from the substrate 11 together with the base layer 13A.

  The pattern structure 10 produced as described above can be configured as, for example, a microchannel device such as a DNA chip that separates a sample solution into a target substance during the flow process. The pattern structure 10 of the present embodiment is configured as an optical device such as an optical waveguide such as an optical fiber by filling an optical material between the pattern layers 15 and optimizing the refractive index of the resist material. Can do.

(Second Embodiment)
FIG. 3 shows a second embodiment of the present invention. In the figure, portions corresponding to those of the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the pattern structure 20 of the present embodiment, the transparent electrode layer 16 is formed between the substrate 11 and the adhesion layer 12. A gap between the pattern layers 15 is filled with a liquid crystal material 17, and a counter substrate 19 including a transparent electrode layer 18 is laminated so as to prevent the liquid crystal material 17 from flowing out. The transparent electrode layers 16 and 18 are made of a transparent conductive oxide such as ITO (Indium Tin Oxide). The substrate 11 and the counter substrate 19 are made of a transparent substrate such as glass or a polymer film substrate. As the liquid crystal material 17, a dispersed liquid crystal material such as PDLC (Polymer Dispersed Liquid Crystal) or PNLC (Polymer Network Liquid Crystal) is preferably used.

  As described above, the pattern structure 20 of the present embodiment constitutes the light control element 21 that controls the emission angle of the light transmitted through the liquid crystal material 17. The transmitted light control by the light control element 21 is performed by turning on / off the voltage between the pair of transparent electrode layers 16 and 18. 4A and 4B are schematic configuration diagrams of a liquid crystal display device 24 including the light control element 21. FIG. The liquid crystal display device 24 has a configuration in which the light control element 21 is disposed between the backlight unit 22 and the liquid crystal display panel 23. As the backlight unit 22, a backlight unit having a relatively high directivity in the front direction is used.

  In this embodiment, the liquid crystal material 17 is a material in which liquid crystal molecules are randomly oriented when no voltage is applied, and the major axis direction of the liquid crystal molecules is aligned in the electric field direction when a voltage is applied. Therefore, when no voltage is applied, the liquid crystal material 17 is clouded as shown in FIG. 4A, and the light control element 21 scatters and emits the light from the backlight unit 22 to the liquid crystal display panel 23. Thereby, the wide viewing angle mode of the liquid crystal display panel 23 is realized. On the other hand, when a voltage is applied, the liquid crystal material 17 is in a transparent state as shown in FIG. 4B, and the light control element 21 linearly transmits the light from the backlight 22 to the liquid crystal display panel 23. Thereby, the narrow viewing angle mode of the liquid crystal display panel 23 is realized.

  According to the present embodiment, since the pattern layer 15 that partitions the liquid crystal material 17 can be formed with high accuracy, for example, the pattern structure 20 having the fine and high aspect ratio pattern layer 15 corresponding to the pixel pitch can be stably and stably formed. It can be formed with high accuracy. Note that the structure of the light control element using a liquid crystal material is not limited to the above example.

(Third embodiment)
5A and 5B show a third embodiment of the present invention. In the figure, portions corresponding to those of the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this embodiment, the pattern structure 10 in which the adhesion layer 12, the base layer 13A, and the pattern layer 15 are sequentially formed on the substrate 11 is manufactured (FIG. 5A). Thereafter, as shown in FIG. 5B, the resist pattern structure 10A including the base layer 13A and the pattern layer 15 is formed by separating the substrate 11 and the base layer 13A. Thereby, it is possible to reduce the thickness of the device including the pattern layer 15.

  In the present embodiment, the substrate 11 is preferably a silicon substrate, and a high-definition and high-aspect pattern layer 15 can be formed. The resist pattern structure 10A can be easily peeled from the substrate 11 by dissolving the adhesion layer 12 and / or the natural oxide film layer using a chemical solution such as hydrofluoric acid. Specifically, the resist pattern structure 10A is peeled from the substrate 11 by immersing the pattern structure 10 in a several percent HF solution for several hours.

It is process sectional drawing of the pattern formation method demonstrated in the 1st Embodiment of this invention. In the pattern formation method of FIG. 1, it is process drawing explaining the detail of the formation process of a pattern layer. It is sectional drawing which shows schematic structure of the pattern structure demonstrated in the 2nd Embodiment of this invention. It is a figure explaining the function of the light control element shown in FIG. It is a figure explaining the formation method of the conductor pattern explaining the 3rd Embodiment of this invention. It is process sectional drawing explaining the formation method of the conventional resist pattern.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10,20 ... Pattern structure, 10A ... Resist pattern structure, 11 ... Substrate, 12 ... Adhesion layer, 13A ... Underlayer, 13B ... Resist layer, 14 ... Mask, 15 ... Pattern layer, 16, 18 ... Transparent electrode layer , 19 ... Counter substrate, 21 ... Light control element

Claims (9)

A substrate,
An underlayer made of a photosensitive resist material formed on the substrate;
A pattern layer comprising a photosensitive resist material patterned on the underlayer, and filled with a liquid crystal material ;
A pattern structure comprising: The pattern structure according to claim 1,
The pattern structure which the photosensitive resist material which comprises the said base layer, and the photosensitive resist material which forms the said pattern layer consist of the same material, respectively. The pattern structure according to claim 1,
The foundation layer and the pattern layer have translucency. The pattern structure according to claim 1,
The underlayer is a pattern structure formed on the substrate via an adhesion layer. The pattern structure according to claim 1,
A pattern structure in which a transparent electrode layer is formed between the substrate and the base layer. The pattern structure according to claim 1,
The said board | substrate is a pattern structure which consists of a polymer film with glass, a polymer film, or an inorganic filler. An underlayer made of a photosensitive resist material is formed on the substrate,
A resist layer made of the same or other photosensitive resist is formed on the underlayer,
By exposing and developing the resist layer, a pattern layer is formed,
A pattern forming method of filling a gap between the pattern layers with a liquid crystal material . The pattern forming method according to claim 7,
The pattern formation method which has the process of apply | coating hexamethyldisilazane on the said board | substrate before the process of forming the said base layer on the said board | substrate. The pattern forming method according to claim 7,
The pattern formation method which has the process of peeling the said resist pattern from the said board | substrate after formation of the said resist pattern.

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