Guide structure and method for manufacturing guide structure

Abstract

To provide a guide structure capable of contributing to improvement of resolution.SOLUTION: Forming a plurality of first protective films extending in one direction in parallel at intervals on a substrate, forming a second protective film on the plurality of first protective films and the substrate, and removing a part of the second protective film on the plurality of first protective films and a part of the plurality of first protective films in this order, forming a plurality of first exposed portions where the substrate is exposed, forming a first recess by etching the first exposed portions of the substrate by first etching, and removing all of the second protective film on the substrate; A method for manufacturing a guide structure, comprising: forming a second exposed portion in which the substrate is exposed at a portion not covered by the plurality of first protective films; forming a second recess by etching the second exposed portion of the substrate by second etching; and removing the entire first protective film on the substrate.SELECTED DRAWING: Figure 15

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a guide structure. [Background technology]

[0002] Currently, X-ray image sensors are being used in a wide range of equipment that requires non-destructive observation, such as X-ray machines, baggage inspection at airports, and pre-inspection for maintenance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4211435 Summary of the Invention [Problem to be solved by the invention]

[0004] There are two types of X-ray image sensors: direct conversion and indirect conversion.

[0005] The direct conversion method converts the intensity of X-rays directly into signals representing the magnitude of negative and positive charges of electrons and holes using an amorphous selenium semiconductor (a-Se). These converted charge magnitude signals are then read as output signals corresponding to pixels using thin film transistors (TFTs) made of semiconductors such as amorphous silicon (a-Si). The output signals are then converted into current signals, which are then converted into digital signals.

[0006] The indirect conversion method converts the intensity of X-rays into visible light using a phosphor (scintillator) or similar, and then converts this light intensity into a signal representing the magnitude of an electric charge using a photodiode array. This signal representing the magnitude of the electric charge is read by a TFT, and the TFT current signal is then converted into a digital signal.

[0007] Currently, the mainstream X-ray image sensor is an indirect conversion type, which can be driven at a relatively low voltage and enables dose reduction. However, this type converts light into visible light using a scintillator, which reduces spatial resolution due to light scattering, generates heat and requires cooling, and has process issues related to fabricating a photodiode for each pixel in a TFT array.

[0008] The inventors of the present invention have conducted extensive research into whether there is room for improvement in the direct conversion method, aiming to improve resolution. As a result, they have discovered a novel guide structure that can contribute to improving the resolution in the focusing of X-rays in X-ray image sensors.

[0009] An object of the present disclosure is to provide a novel method for manufacturing a guide structure that can contribute to improving resolution, and a guide structure obtained by the manufacturing method. [Means for solving the problem]

[0010] The present disclosure includes the following aspects: [Section 1] A method for manufacturing a guide structure, the method comprising: forming a plurality of first protective films extending in one direction and parallel to each other at intervals on a substrate; forming a second protective film on the plurality of first protective films and on the substrate; removing a portion of the second protective film on the plurality of first protective films and a portion of the plurality of first protective films in this order to form a plurality of first exposed portions where the substrate is exposed; etching the first exposed portion of the substrate with a first etch to form a first recess; removing all of the second protective films on the substrate to form second exposed portions in which the substrate is exposed in portions not covered by the plurality of first protective films; a second etch to etch the second exposed portion of the substrate to form a second recess; and A method for manufacturing a guide structure, comprising removing all of the first protective film on the substrate. [Section 2] The plurality of first protective films extending in one direction in parallel with a gap therebetween, forming a first protective film to cover the surface of the substrate; forming a plurality of first resists on the first protective film, the first resists extending in one direction and in parallel with each other at intervals; Item 2. The method for manufacturing a guide structure according to item 1, wherein the guide structure is created by removing the first protective film that is not covered with the plurality of first resists. [Section 3] The first exposed portion forming a second resist having a plurality of openings on the second protective film after the second protective film is formed; wherein the plurality of openings are located on the plurality of first protective films at intervals, 3. The method for manufacturing a guide structure according to item 1 or 2, wherein the guide structure is created by removing a portion of the second protective film and a portion of the first protective film in the plurality of openings in this order. [Section 4] Item 4. The method for manufacturing a guide structure according to Item 3, wherein the plurality of openings in the second resist are arranged in a lattice pattern or a staggered pattern. [Section 5] 5. The method for manufacturing a guide structure according to any one of items 1 to 4, wherein the first recesses are arranged in a lattice pattern or a staggered pattern. [Section 6] After forming the first recess and before forming the second exposed portion, forming a recess protection film on the first recess; 6. The method for manufacturing a guide structure according to any one of items 1 to 5, wherein the second exposed portion is a portion where the plurality of first protective films and the recess protective film are not present. [Section 7] Item 7. The method for manufacturing a guide structure according to any one of items 1 to 6, wherein the first recess and the second recess have a V-shaped groove structure. [Section 8] 8. The method for manufacturing a guide structure according to any one of items 1 to 7, wherein the first protective film is an oxide film. [Section 9] Item 9. The method for manufacturing a guide structure according to any one of items 1 to 8, wherein the second protective film is a nitride film. [Section 10] A guide structure for guiding electromagnetic waves, the guide structure having a plurality of columnar protrusions. [Section 11] Item 11. The guide structure according to item 10, wherein the plurality of columnar protrusions are arranged in a lattice or staggered pattern. [Section 12] Item 12. The guide structure according to item 10 or 11, wherein the upper surfaces of the plurality of columnar protrusions are on the same plane. [Section 13] 13. The guide structure according to any one of items 10 to 12, wherein the columnar shape is a frustum shape. [Effects of the Invention]

[0011] The method for manufacturing a guide structure according to the present disclosure provides a guide structure that can contribute to improving the resolution of an X-ray image sensor by concentrating X-rays, even in the case of a direct conversion method. [Brief explanation of the drawings]

[0012] A method for manufacturing the guide structure of the present disclosure according to one embodiment will be described below.

[0013] [Figure 1A] FIG. 1A is a schematic perspective view showing a state in which a first protective film is formed on a substrate. [Figure 1B] FIG. 1B is a cross-sectional view taken along line AA in FIG. 1A. [Figure 2A] FIG. 2A is a schematic perspective view showing a state in which a first resist is formed on a first protective film. [Figure 2B] FIG. 2B is a cross-sectional view taken along line AA in FIG. 2A. [Figure 3] FIG. 3 is a diagram schematically illustrating the first mask. [Figure 4A]FIG. 4A is a schematic perspective view showing a state in which a plurality of first resists extending in one direction and parallel to each other at intervals are formed on a first protective film. [Figure 4B] FIG. 4B is a cross-sectional view taken along line AA in FIG. 4A. [Figure 4C] FIG. 4C is a cross-sectional view taken along line BB in FIG. 4A. [Figure 5A] FIG. 5A is a schematic perspective view showing a first protective film covered with a plurality of first resists. [Figure 5B] FIG. 5B is a cross-sectional view taken along line AA in FIG. 5A. [Figure 5C] FIG. 5C is a cross-sectional view taken along line BB in FIG. 5A. [Figure 6A] FIG. 6A is a schematic perspective view showing a state in which a plurality of first protective films extending in one direction and parallel to each other at intervals are formed on a substrate in a step of forming a plurality of first protective films. [Figure 6B] FIG. 6B is a cross-sectional view taken along line AA in FIG. 6A. [Figure 6C] FIG. 6C is a cross-sectional view taken along line BB in FIG. 6A. [Figure 7A] FIG. 7A is a schematic perspective view showing the state after the second protective film is formed. [Figure 7B] FIG. 7B is a cross-sectional view taken along line AA in FIG. 7A. [Figure 7C] FIG. 7C is a cross-sectional view taken along line BB in FIG. 7A. [Figure 8A] FIG. 8A is a schematic perspective view showing a state in which a plurality of openings are provided in the second resist. [Figure 8B] FIG. 8B is a cross-sectional view taken along line AA in FIG. 8A. [Figure 8C] FIG. 8C is a cross-sectional view taken along line BB in FIG. 8A. [Figure 9A] FIG. 9A is a schematic diagram showing the state of the openings in the second mask. [Figure 9B] FIG. 9B is a schematic diagram showing the state of the openings in the second mask. [Figure 10A]FIG. 10A is a schematic perspective view showing a state after the first exposed portion is provided through the second mask. [Figure 10B] FIG. 10B is a cross-sectional view taken along line AA in FIG. 10A. [Figure 10C] FIG. 10C is a cross-sectional view taken along line BB in FIG. 10A. [Figure 11A] FIG. 11A is a schematic perspective view showing the state after the second resist has been removed. [Figure 11B] FIG. 11B is a cross-sectional view taken along line AA in FIG. 11A. [Figure 11C] FIG. 11C is a cross-sectional view taken along line BB in FIG. 11A. [Figure 12A] FIG. 12A is a schematic perspective view showing a state in which a first recess is provided. [Figure 12B] FIG. 12B is a cross-sectional view taken along line AA in FIG. 12A. [Figure 12C] FIG. 12C is a cross-sectional view taken along line BB in FIG. 12A. [Figure 13A] FIG. 13A is a schematic perspective view showing a state in which a recess protection film is provided. [Figure 13B] FIG. 13B is a cross-sectional view taken along line AA in FIG. 13A. [Figure 13C] FIG. 13C is a cross-sectional view taken along line BB in FIG. 13A. [Figure 14A] FIG. 14A is a schematic perspective view showing the state after all the second protective films have been removed. [Figure 14B] FIG. 14B is a cross-sectional view taken along line AA in FIG. 14A. [Figure 14C] FIG. 14C is a cross-sectional view taken along line BB in FIG. 14A. [Figure 15] FIG. 15 is a schematic perspective view showing a guide structure according to one embodiment of the present disclosure. [Figure 16] FIG. 16 is a schematic diagram illustrating a state in which a guide structure according to an embodiment of the present disclosure and an electronic device are joined together. DETAILED DESCRIPTION OF THE INVENTION

[0014] The following describes in more detail the manufacturing method of the guide structure of the present disclosure and the guide structure obtained by the manufacturing method. Although the description will be made with reference to drawings as necessary, the various elements in the drawings are merely shown schematically and exemplarily to facilitate understanding of the manufacturing method of the guide structure of the present disclosure and the guide structure obtained by the manufacturing method, and the appearance and / or dimensional ratios may differ from the actual products.

[0015] The various numerical ranges mentioned in this specification are intended to include both the lower and upper limits. For example, a numerical range of 1 to 10 can be interpreted as including the lower limit of 1 and the upper limit of 10.

[0016] <Manufacturing method of guide structure> The manufacturing method of the guide structure of the present disclosure includes: forming a plurality of first protective films extending in one direction and parallel to each other at intervals on a substrate; forming a second protective film on the plurality of first protective films and on the substrate; removing a portion of the second protective film on the plurality of first protective films and a portion of the plurality of first protective films in this order to form a plurality of first exposed portions where the substrate is exposed; etching the first exposed portion of the substrate with a first etch to form a first recess; removing all of the second protective films on the substrate to form second exposed portions in which the substrate is exposed in portions not covered by the plurality of first protective films; a second etch to etch the second exposed portion of the substrate to form a second recess; and Removing all of the first protective film on the substrate.

[0017] The manufacturing method of the guide structure of the present disclosure will be described in detail below.

[0018] [Formation of first protective film] First, a substrate 10 is prepared. Then, as shown in Figures 1A and 1B, a first protective film 11 is formed to cover the surface of the substrate 10. Here, the first protective film 11 covering the surface of the substrate 10 is one-sided or single-sided, as shown in Figures 1A and 1B. The first protective film 11 covering the surface of the substrate 10 may be formed by thermally oxidizing the substrate 10.

[0019] -substrate The substrate is a substrate used in the fields of semiconductors, semiconductor elements, etc., and may be, for example, a Si wafer. The shape of the substrate is not particularly limited, and may be circular, quadrangular (for example, square, rectangular, etc.), etc.

[0020] The size of the substrate, in diameter or length of one side, may be 1 inch (2.54 cm) or more, 2 inches (5.08 cm) or more, 3 inches (7.62 cm) or more, 4 inches (10.16 cm) or more, 5 inches (12.7 cm) or more, 7 inches (17.78 cm) or more, or 10 inches (25.4 cm) or more, and may be 20 inches (50.8 cm) or less, 17 inches (43.18 cm) or less, 15 inches (38.1 cm) or less, 13 inches (33.02 cm) or less, 11 inches (27.94 cm) or less, or 9 inches (22.86 cm) or less.

[0021] In one embodiment, the substrate size may be 4 inches (10.16 cm) in diameter.

[0022] The thickness of the substrate may be 100 μm or more, 200 μm or more, 300 μm or more, 400 μm or more, 500 μm or more, 600 μm or more, 800 μm or more, or 1000 μm or more, and may be 2000 μm or less, 1800 μm or less, 1600 μm or less, 1400 μm or less, 1200 μm or less, 1000 μm or less, or 800 μm or less.

[0023] In one embodiment, the thickness of the substrate may be 525 μm.

[0024] The substrate may be either P-type or N-type, but when used to guide X-rays, the substrate is preferably N-type.

[0025] -thermal oxidation 1A and 1B may be formed by thermally oxidizing the substrate 10. The temperature during thermal oxidation is not particularly limited, but may be 800° C. or higher, 900° C. or higher, or 1000° C. or higher, and may be 1200° C. or lower, 1100° C. or lower, or 1000° C. or lower. Thermal oxidation may be performed using, for example, a thermal oxidation furnace, or may be performed by commercially available means.

[0026] The duration of the thermal oxidation may be 1 hour or more, 2 hours or more, or 3 hours or more, and may be 6 hours or less, 5 hours or less, or 4 hours or less.

[0027] The atmosphere for thermal oxidation is not particularly limited, but may be an atmosphere containing water vapor and / or oxygen.

[0028] In one embodiment, the substrate may be placed in an oxidation furnace at 1000° C., and water and oxygen may be introduced therein for three hours to form a first protective film on the substrate.

[0029] The thickness of the first protective film may be 100 nm or more, 300 nm or more, 500 nm or more, or 700 nm or more, and may be 2000 nm or less, 1500 nm or less, 1200 nm or less, or 1000 nm or less.

[0030] [Formation of first resist] 2A and 2B, a first resist 11R is formed so as to cover the single surface of the first protective film 11. The first resist 11R may be formed by the following method.

[0031] - Dehydration bake Before applying the first resist to the first protective film, a dehydration bake may be performed to improve the adhesion of the resist. The conditions for the dehydration bake are not particularly limited, but the temperature may be 100°C or higher, 120°C or higher, or 140°C or higher, and may be 200°C or lower, 180°C or lower, or 160°C or lower. The time may be 5 minutes or longer, 10 minutes or longer, or 30 minutes or longer, and may be 60 minutes or shorter, 50 minutes or shorter, or 40 minutes or shorter. In one embodiment, the dehydration bake may be performed at 120°C for 10 minutes.

[0032] -OAP processing After the dehydration bake, and before applying the first resist to the first protective film, a hexamethyldisilazane (OAP) treatment may be performed to improve the adhesion of the resist, which helps prevent the resist layer from peeling during development.

[0033] The conditions for the OAP treatment are not particularly limited. However, from the viewpoint of uniformly applying hexamethyldisilazane to the substrate, the OAP treatment may be performed by first applying hexamethyldisilazane to the substrate at a low rotation speed and then rotating the substrate at a high rotation speed. Here, "low rotation speed" refers to a speed between 300 rpm and 700 rpm. "High rotation speed" refers to a speed between 2000 rpm and 4000 rpm. The rotation time is not particularly limited, but may be adjusted appropriately between 1 second and 30 seconds. In one embodiment, the OAP treatment may involve applying hexamethyldisilazane to the substrate while rotating the substrate at 500 rpm for 5 seconds and then at 3000 rpm for 20 seconds.

[0034] Although the conditions for the OAP treatment are exemplified by spin coating, the OAP treatment can also be performed by known methods. For example, the OAP treatment may be performed by a suitable coating method such as roll coating, flow coating, dip coating, spray coating, or doctor coating so as to achieve a predetermined coating thickness.

[0035] - Application of the first resist A first resist is applied so as to cover the entire first protective film covering the substrate surface. The conditions for applying the first resist are not particularly limited, but may be the same as those for the OAP treatment described above. The first resist may be a commercially available resist, such as OFPR800LB (manufactured by Tokyo Ohka Kogyo Co., Ltd.).

[0036] After application of the first resist and before exposure, pre-baking may be performed to evaporate the solvent inside the resist. The pre-baking conditions are not particularly limited, but the temperature may be 80°C or higher, 90°C or higher, or 100°C or higher, and 150°C or lower, 130°C or lower, or 110°C or lower. The pre-baking time may be 60 seconds or higher, 90 seconds or higher, or 120 seconds or higher, and 240 seconds or lower, 210 seconds or lower, or 180 seconds or lower. In one embodiment, pre-baking may be performed at 90°C for 90 seconds.

[0037] By the above method, the first resist 11R can be formed so as to cover a single surface of the first protective film 11. Next, by subjecting the first resist 11R to exposure and development, which will be described in detail below, a plurality of first resists 11R extending in one direction in parallel with spaces between them can be formed on the first protective film 11 covering the substrate surface, as shown in Figures 2A and 2B.

[0038] -exposure After the first resist is applied, photolithography is performed. Specifically, the first resist 11R formed on the substrate is exposed through a first mask 21. As shown in FIG. 3, the first mask 21 has a first mask pattern portion 211 and a plurality of openings 212. The plurality of openings 212 extend in one direction in parallel with a plurality of intervals. When the resist is exposed through the first mask 21, the resist is patterned to correspond to the plurality of openings 212.

[0039] For example, when photolithography is performed in a positive tone, if the first mask pattern portion is used as a light-shielding portion, then subsequent development can form multiple first protective films extending parallel to one another at intervals on the substrate, as shown in Figures 4A to 4C.

[0040] For example, when negative photolithography is performed, subsequent development can form a plurality of first protective films extending in one direction and parallel to each other at intervals on the substrate as shown in FIGS. 4A to 4C.

[0041] The exposure conditions are not particularly limited, but the illuminance is preferably 10 w / cm 2 Above, 20w / cm 2 or more, or 30w / cm 2 or more, or 50 w / cm 2 Below, 40w / cm 2 or less, or 30w / cm 2 The exposure time may be 3 seconds or more, 4 seconds or more, or 5 seconds or more, and may be 10 seconds or less, 8 seconds or less, or 6 seconds or less. The exposure conditions may be adjusted arbitrarily in terms of illuminance and time, provided that illuminance x time ≥ 100. In one embodiment, the illuminance is 20 watts / cm 2 , the exposure time may be 5.5 seconds.

[0042] First Mask As shown in FIG. 3, the width W1 of each opening 212 in the first mask 21 may be 30 μm or more, 40 μm or more, 50 μm or more, 60 μm or more, 80 μm or more, 100 μm or more, 150 μm or more, 200 μm or more, 250 μm or more, 300 μm or more, or 350 μm or more, or 400 μm or less, 350 μm or less, 300 μm or less, 250 μm or less, 200 μm or less, 150 μm or less, 100 μm or less, 80 μm or less, or 60 μm or less.

[0043] As shown in FIG. 3, the distance D1 between each of the openings 212 in the first mask 21 may be 1 μm or more, 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, 40 μm or more, 50 μm or more, 60 μm or more, or 70 μm or more, or may be 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, or 20 μm or less.

[0044] -developing After exposure, the first resist is developed using a developer. The developer may be a commercially available developer, such as NMD-3 (manufactured by Tokyo Ohka Kogyo Co., Ltd.). Other developers that can be used include alkaline solution developers such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), and tetrabutylammonium hydroxide (TBAH). The solution concentration may be, for example, 0.1 to 10% by mass, and preferably 2 to 5% by mass.

[0045] Other examples of the developer include organic solvents, such as aromatic compounds such as benzene, xylene, and toluene; alcohols such as methanol, 1-propanol, isopropanol, and 1-butanol; ketones such as acetone, methyl ethyl ketone, and 2-octanone; and ethers such as tetrahydrofuran and dioxane.

[0046] The development conditions are not particularly limited, but the development time may be 60 seconds or more, 90 seconds or more, or 120 seconds or more, and may be 300 seconds or less, 240 seconds or less, or 180 seconds or less.

[0047] After development, the film may be washed with running water for a period of time that is not particularly limited, but may be 60 seconds or more and 120 seconds or less.

[0048] -Post-bake After development, post-baking may be performed. Post-baking can harden the resist, making it more resistant to subsequent processes. The post-baking conditions are not particularly limited, but the temperature may be 100°C or higher, 120°C or higher, or 140°C or higher, and may be 200°C or lower, 180°C or lower, or 160°C or lower. The time may be 60 seconds or higher, 90 seconds or higher, or 120 seconds or higher, and may be 240 seconds or lower, 180 seconds or lower, or 120 seconds or lower. In one embodiment, post-baking may be performed at 120°C for 90 seconds.

[0049] By going through the above steps, a plurality of first resists extending in one direction and parallel to each other at intervals can be formed on the first protective film covering the surface of the substrate.

[0050] [Step of forming multiple first protective films] After forming a plurality of first resists spaced apart and extending in one direction in parallel on a first protective film covering the surface of the substrate, the first protective film that is not covered by the plurality of first resists is removed. As a result of this removal, only the first protective film 11 covered by the plurality of first resists 11R remains on the substrate 10, as shown in Figures 5A to 5C. The formation of the plurality of first protective films 11 spaced apart and extending in one direction in parallel on the substrate 10 may be achieved by the following etching and removal of the first resist.

[0051] -etching The first protective film not covered by the plurality of first resists may be removed using an etching solution, such as a commercially available etching solution such as HF or BHF. Furthermore, the first protective film not covered by the plurality of first resists may be removed by an etching gas. The etching gas may be a commercially available etching gas, such as CF4 or CH3F. In a preferred embodiment, the first protective film not covered by the plurality of first resists may be removed by reactive ion etching (RIE) using the etching gas.

[0052] The time required to remove the first protective film not covered by the plurality of first resists is not particularly limited, but may be 5 minutes or more, 7 minutes or more, or 10 minutes or more, and may be 20 minutes or less, 15 minutes or less, or 10 minutes or less. In one embodiment, the removal may be performed for 7 minutes using BHF as an etching solution.

[0053] After removal, the material may be washed with running water. The washing time is not particularly limited, but may be from 1 minute to 10 minutes. Washing may be performed multiple times.

[0054] 5A to 5C, the multiple first protective films 11 formed in the first protective film forming step are arranged in parallel at regular intervals on the substrate 10. Here, "parallel" means that, among the multiple first protective films 11, the center line of one first protective film 11 and the center line of another first protective film 11 extend in the same direction while maintaining a regular interval between them.

[0055] The first protective film is not particularly limited, but may be an oxide, nitride, oxynitride, or the like of the material constituting the substrate, and is preferably an oxide. In this regard, the first protective film may be an oxide film.

[0056] The shape of the plurality of first protective films is not particularly limited, but may be rectangular, preferably oblong as shown in FIGS. 4A to 4C.

[0057] The spacing between each of the multiple first protective films may be 30 μm or more, 40 μm or more, 50 μm or more, 60 μm or more, or 70 μm or more, and may be 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, or 60 μm or less.

[0058] The width of each of the multiple first protective films may be 1 μm or more, 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, 40 μm or more, 50 μm or more, 60 μm or more, or 70 μm or more, and may be 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, or 20 μm or less.

[0059] -Removal of the first resist After the etching, the first resists 11R are removed to form a plurality of first protective films 11 extending in one direction and parallel to each other at intervals on the substrate 10, as shown in Figures 6A to 6C. The first resists may be removed by ultrasonic cleaning. The ultrasonic cleaning may be performed until the first resists are removed, for example, for 3 minutes to 10 minutes.

[0060] [Second protective film forming step] The second protective film forming step includes forming a second protective film 12 on the plurality of first protective films 11 and on the substrate 10, as shown in FIGS. 7A to 7C.

[0061] The second protective film is not particularly limited, but may be an oxide, nitride, oxynitride, or the like of the material constituting the substrate, and is preferably a nitride. In this regard, the second protective film may be a nitride film.

[0062] The second protective film may be formed by depositing a nitride film on the substrate by, but not limited to, LPCVD, plasma CVD, or thermal nitridation.

[0063] An example of the LPCVD method is to form a nitride film (e.g., SiN) on a substrate by vapor-phase reaction of a source gas (e.g., Si gas) and ammonia gas at a temperature of 700°C to 800°C. An example of the plasma CVD method is to convert a source gas and ammonia gas into plasma and form a nitride film on a substrate at a low temperature (300°C to 400°C). An example of the thermal nitridation method is to obtain a nitride film by heating a substrate to 1100°C or higher in a nitrogen atmosphere, or to obtain a nitride oxide film by thermal nitriding an oxide film on a substrate.

[0064] The thickness of the second protective film may be 30 nm or more, 50 nm or more, or 70 nm or more, and may be 200 nm or less, 150 nm or less, 120 nm or less, or 100 nm or less.

[0065] [Second resist formation step] In the second resist formation step, as shown in FIGS. 8A to 8C, a second resist 12R having a plurality of openings 121 is formed on the formed second protective film 12. The second resist 12R having a plurality of openings 121 may be formed by first forming a single surface of the second resist 12R on the second protective film 12, and then providing the openings 121. Here, each of the plurality of openings 121 is also located on a plurality of first protective films 11 at intervals. The second resist 12R having a plurality of openings 121 may be formed by the method exemplified below.

[0066] - Dehydration bake Before applying the second resist onto the second protective film, a dehydration bake may be performed to improve the adhesion of the resist, and the dehydration bake conditions may be the same as those described in [Formation of the First Resist].

[0067] -OAP processing After the dehydration bake, a hexamethyldisilazane treatment (OAP treatment) may be performed before applying a second resist to the second protective film to improve the adhesion of the resist. The OAP treatment conditions may be the same as those described in [Formation of the First Resist].

[0068] - Coating of second resist A second resist is applied so as to cover the entire second protective film covering the substrate surface. The conditions for applying the second resist are not particularly limited, but the same conditions as those for the OAP treatment described above may be adopted. The second resist may be a commercially available resist, such as OFPR800LB (manufactured by Tokyo Ohka Kogyo Co., Ltd.).

[0069] After the second resist is applied and before exposure, pre-baking may be performed to improve the adhesion of the resist, and the pre-baking conditions may be the same as those described in [Formation of the First Resist].

[0070] -exposure After the second resist is applied, photolithography is performed. Specifically, the second resist formed on the substrate is exposed to light through a second mask.

[0071] 9A and 9B, the second mask 22 has a plurality of openings 221 and a mask pattern portion 222. When the resist is exposed through the second mask 22, the resist is patterned to correspond to the openings 221.

[0072] The arrangement of the plurality of openings in the second mask is not particularly limited as long as they are positioned on the first protective film, and the openings may be arranged in a grid pattern or a staggered pattern as shown in Figures 9A and 9B. Arranging the openings in a staggered pattern is preferable because it allows for a larger number of convex portions of the guide structure per area, as will be described later.

[0073] The exposure conditions may be the same as those described in [Formation of the first resist].

[0074] Second Mask The respective spacings D2 between the openings 221 in the second mask 22 may be 1 μm or more, 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, 40 μm or more, 50 μm or more, 60 μm or more, or 70 μm or more, and may be 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, or 20 μm or less.

[0075] The length W2 of the opening 221 in the second mask 22 may be 50 μm or more, 80 μm or more, 100 μm or more, 150 μm or more, 200 μm or more, 250 μm or more, 300 μm or more, or 350 μm or more, and may be 400 μm or less, 350 μm or less, 300 μm or less, 250 μm or less, 200 μm or less, 150 μm or less, 100 μm or less, or 80 μm or less.

[0076] The width W3 of the opening 221 in the second mask 22 may be 30 μm or more, 40 μm or more, 50 μm or more, 60 μm or more, 80 μm or more, 100 μm or more, 150 μm or more, 200 μm or more, 250 μm or more, 300 μm or more, or 350 μm or more, or 400 μm or less, 350 μm or less, 300 μm or less, 250 μm or less, 200 μm or less, 150 μm or less, 100 μm or less, 80 μm or less, or 60 μm or less.

[0077] 9B has a plurality of openings 221, which are arranged with a vertical and horizontal offset. Such an offset arrangement can be determined, for example, by the length W4 of the region where openings A and B in FIG. 9B overlap in the short direction.

[0078] In the second mask 22, W4 may be -50 μm or more, -30 μm or more, -20 μm or more, -10 μm or more, 0 μm or more, 10 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more, or may be 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, or 10 μm or less.

[0079] Note that W4 being 0 μm means that the tip of opening A and the tip of opening B are on the same straight line. If the value of W4 is negative, opening A and opening B are spaced apart from each other.

[0080] The shape of the opening of the second mask is not particularly limited, and may be rectangular, polygonal, elliptical, etc.

[0081] -developing After exposure, the second resist is developed using a developer. The development conditions for the second resist may be the same as those described in [Formation of the First Resist].

[0082] -Post-bake After development, post-baking may be performed under the conditions described in [Formation of the first resist].

[0083] By going through the above steps, a second resist 12R having a plurality of openings 121 can be formed on the formed second protective film 12, as shown in FIGS. 8A to 8C.

[0084] [First exposed portion forming step] The first exposed portion forming step includes removing, in this order, portions of the second protective film on the plurality of first protective films and portions of the plurality of first protective films, thereby forming a plurality of first exposed portions where the substrate is exposed. In the example shown in FIGS. 8B and 8C, the second protective film 12 on the first protective film 11 at the plurality of openings 121 in the second resist 12R and portions of the plurality of first protective films 11 are removed in this order. As a result, as shown in FIGS. 10A to 10C, a plurality of first exposed portions 101 where the substrate 10 is exposed are formed at the locations of the plurality of openings 121. After forming the plurality of first exposed portions 101, the second resist 12R is removed, resulting in the structure shown in FIGS. 11A to 11C. The first exposed portion forming step will be described in detail below.

[0085] -Removal of the second protective film The second protective film on the first protective film in the plurality of openings of the second mask may be removed by dry etching. The dry etching is not particularly limited, but reactive ion etching (RIE), plasma etching, sputter etching, etc. may be employed. As the dry etching, reactive ion etching (RIE) is preferred, and ICP (inductively coupled plasma)-RIE is particularly preferred.

[0086] The gas used for dry etching may be CF4, SF6, CHF3, C4F8, NF3, O2, or a mixture thereof.

[0087] The flow rate of the etching gas may be 10 sccm or more and 200 sccm or less, and is preferably 10 sccm or more and 50 sccm or less.

[0088] The pressure of the etching gas may be 3 mtorr or more and 500 mtorr or less, and preferably 100 mtorr or more and 400 mtorr or less.

[0089] The RF power may be 10 W or more and 300 W or less, and is preferably 10 W or more and 100 W or less.

[0090] The treatment time may be from 10 seconds to 20 minutes, and is preferably from 30 seconds to 10 minutes.

[0091] -Removal of the second resist Next, the second resist may be removed by the same method as used to remove the first resist in the step of forming a plurality of first protective films.

[0092] -Removal of the first protective film After removing the second protective film on the first protective film in the plurality of openings of the second mask, a portion of the first protective film in the openings is removed. The etching conditions described in the "Forming a plurality of first protective films" may be adopted for removing the portion of the first protective film.

[0093] By carrying out the removal of the second protective film and the removal of the first protective film, first exposed portions are formed in which the substrate is exposed at the locations where the plurality of openings in the second mask are located.

[0094] 11A to 11C, the first exposed portion 101 may cross the first protective film 11. Such a crossing makes it easier to form the convex portion of the guide structure, which will be described later.

[0095] The second resist may be removed after the first protective film is removed.

[0096] [First recess formation step] The first recess formation step includes performing a first etching process to form a first recess by etching a first exposed portion of the substrate. Specifically, as shown in Figures 11A to 11C, the first etching process is performed in a state where a first protective film 11 and a second protective film 12 are formed on a substrate 10. By performing the first etching process, the substrate 10 is etched at the first exposed portion 101, and a first recess 101U is formed in the first exposed portion 101.

[0097] -First etching The first etching may be performed by wet etching. The wet etching is not particularly limited, but may be either a dip etching method or a spin etching method. The first etching is preferably anisotropic etching.

[0098] The chemical solution used for wet etching may be an alkaline solution, such as a TMAH (tetramethyl ammonium hydroxide) solution, a sodium hydroxide solution, or a potassium hydroxide solution, preferably a TMAH solution, whose concentration may be 10% by mass or more and 30% by mass or less, preferably 15% by mass or more and 25% by mass or less.

[0099] The etching temperature may be 30° C. or higher and 90° C. or lower, and preferably 60° C. or higher and 90° C. or lower. The etching time may be 1 hour or higher and 4 hours or lower, and preferably 1 hour 30 minutes or higher and 3 hours or lower. The first etching may be performed until a V-shaped groove structure is formed in the B-B cross section, as shown in FIG. 12C.

[0100] Under the above conditions, the first exposed portion of the substrate is etched, and as shown in FIGS. 12A to 12C, a first recess 101U is formed in the first exposed portion 101.

[0101] The arrangement of the first recesses is not particularly limited, and as shown in Figures 12A to 12C, the first recesses may be arranged in a grid pattern or a staggered pattern. Arranging the first recesses in a staggered pattern is preferable because it allows for a larger number of protrusions of the guide structure per area, as described below. The arrangement of the first recesses corresponds to the arrangement of the openings of the second mask.

[0102] The depth of the first recess may be 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, 50 μm or more, 70 μm or more, 100 μm or more, 150 μm or more, or 200 μm or more, and may be 300 μm or less, 250 μm or less, 200 μm or less, 150 μm or less, 130 μm or less, 100 μm or less, 80 μm or less, 60 μm or less, or 50 μm or less.

[0103] [Second exposed portion forming step] After the first recess is formed, a second exposed portion forming step is carried out. The second exposed portion forming step may include forming a recess protective film in the first recess, removing all of the second protective film on the substrate, and forming second exposed portions where the substrate is exposed in areas where the plurality of first protective films and the recess protective film are not present.

[0104] - Formation of a protective film for recesses After forming the first recess, a recess protection film may be formed in the first recess before removing all of the second protection film on the substrate. The recess protection film may be formed under the thermal oxidation conditions described in [Formation of the first protection film].

[0105] 13A to 13C show a state in which a recess protective film 1011 is formed on the first recess 101U. The recess protective film is provided so as to cover the entire first recess 101U. By providing the recess protective film 1011, it becomes easier to remove all of the second protective films later.

[0106] -Removal of all secondary protective coatings In the second exposed portion forming step, all of the second protective film on the substrate is removed. The etching solution used to remove the second protective film is not particularly limited, but phosphoric acid alone or a phosphoric acid solution may be used. The temperature of the etching solution may be 150°C or higher and 200°C or lower, preferably 160°C or higher and 180°C or lower. The etching time may be 10 minutes or higher and 2 hours or lower, preferably 30 minutes or higher and 1 hour 30 minutes or lower.

[0107] By removing all of the second protective films 12 on the substrate 10, second exposed portions 102 are formed on the substrate 10, as shown in Figures 14A to 14C. Specifically, the second exposed portions 102 are formed in areas where the plurality of first protective films 11 and recess protective films 1011 are not present.

[0108] [Second recess formation step] After forming the second exposed portion, a second recess is formed. The second recess forming step includes etching the second exposed portion of the substrate by a second etch to form a second recess.

[0109] -Second etching The second etching conditions may be the same as those for the first etching in the "first recess formation step." In particular, the second etching is preferably anisotropic etching. The second etching may be performed until a V-shaped groove structure is formed in the second recess 102U in the AA cross section, as shown in FIGS. 14A and 14B.

[0110] The depth of the second recess may be 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, 50 μm or more, 70 μm or more, 100 μm or more, 150 μm or more, or 200 μm or more, and may be 300 μm or less, 250 μm or less, 200 μm or less, 150 μm or less, 130 μm or less, 100 μm or less, 80 μm or less, 60 μm or less, or 50 μm or less.

[0111] -Removal of all primary protective coatings After the second etching, all of the first protective films on the substrate are removed. The removal of the first protective films may be performed under the conditions described in the etching step of forming multiple first protective films.

[0112] A guide structure can be obtained by the method for manufacturing a guide structure described above. In one embodiment of the method for manufacturing a guide structure according to the present disclosure, two-stage anisotropic wet etching is performed using a first etching step and a second etching step. This two-stage wet etching step makes it easier to manufacture the guide structure described in detail below.

[0113] <Guide structure> The guide structure of the present disclosure is a guide structure for guiding electromagnetic waves, and has a plurality of columnar protrusions. The guide structure of the present disclosure can be used to guide electromagnetic waves, particularly X-rays.

[0114] The guide structure of the present disclosure is used by being joined to an electronic device. The portion where the guide structure and the electronic device are joined is the top (tip) of the convex portion of the guide structure. The top (or tip) of the convex portion of the guide structure is planar.

[0115] 15, the apex 3 of the convex portion of the guide structure is bonded to the electronic device. When the guide structure is used in an image sensor, the guide structure of the present disclosure can be bonded to the top of a storage capacitor or the like of the image sensor to form the image sensor.

[0116] An example of focusing electromagnetic waves using the guide structure of the present disclosure is shown in Figure 16. Electromagnetic waves 30 are irradiated from the bottom 2 of the convex portion of the guide structure 10 toward the top 3 that is bonded to the device. The electromagnetic waves enter the guide structure from the bottom 2 of the guide structure. Electrons and holes are generated in the guide structure 1 by the electromagnetic waves 30 that enter the guide structure, and the magnitude of the negative and positive charges of these electrons and holes can be converted into signals that can be read.

[0117] 16 has a tapered structure from the bottom 2 to the top 3. Therefore, the electromagnetic wave 30 focused at the bottom 2 of the guide structure travels in a manner that it converges as it travels from the bottom 2 to the top 3. Similarly, electrons generated in the guide structure 1 can also converge as it travels from the bottom 2 to the top 3. The converged electrons can reach the sensor 41 of the electronic device 40 that is joined to the top 3.

[0118] By focusing the electromagnetic waves using the guide structure described above, it is possible to ensure the dose required for detection while suppressing the dose by focusing the electromagnetic waves, even in the direct conversion method. This may lead to the realization of an image sensor with high resolution. It may also lead to the realization of an image sensor that can operate at room temperature.

[0119] Furthermore, by focusing electromagnetic waves using the above-described guide structure, the guide structure of the present disclosure can focus X-rays, which are difficult to refract with lenses. The guide structure of the present disclosure makes it easy to increase the photoelectric conversion efficiency for X-rays and is compatible with semiconductors made from silicon substrates.

[0120] Various aspects of the guide structure of the present disclosure are described in detail below.

[0121] The plurality of columnar protrusions of the guide structure of the present disclosure are arranged in a specific pattern. The arrangement may be a lattice pattern (i.e., a parallel arrangement of the protrusions) or a staggered pattern (i.e., a crossed arrangement of the protrusions). The staggered pattern is preferable to the lattice pattern because it is easier to increase the density of the protrusions per area.

[0122] The tops 3 of the multiple columnar protrusions of the guide structure of the present disclosure may be on the same plane as shown in Fig. 15. Having the tops 3 of the multiple columnar protrusions on the same plane makes it easier for each of the multiple tops 3 to be uniformly bonded to the electronic device 40 as shown in Fig. 16.

[0123] The plurality of columnar protrusions of the guide structure of the present disclosure may have a frustum shape. The frustum shape may be a pyramid shape or a cone shape, and preferably a quadrangular frustum shape. [Example]

[0124] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to these examples.

[0125] The substrate used was a Si wafer, which had a diameter of 4 inches, a surface orientation of (100), a P type, and a thickness of 525 μm.

[0126] First, the wafer was placed in an oxidation furnace at 1000°C, and water and oxygen were introduced for three hours to grow an oxide film on the silicon.

[0127] Photolithography was performed under the conditions in Table 1, and patterning was performed using Mask #1 (D1 = 50 μm, W1 = 50 μm) shown in Figure 3. After that, oxide film etching was performed according to the conditions in Table 2, and ultrasonic cleaning was performed for a total of 4 minutes to remove the resist.

[0128] [Table 1]

[0129] [Table 2]

[0130] A nitride film was formed on the patterned layer by LPCVD, and then photolithography was performed again using Mask #2 shown in 9B (W2 = 110 μm, W3 = 30 μm, W4 = 10 μm, D2 = 50 μm, staggered arrangement) to perform patterning.

[0131] Nitride film etching was performed using RIE under the conditions in Table 3. After oxide film etching was performed under the conditions in Table 2, the resist was removed. After that, wet etching of the silicon substrate was performed under the conditions in Table 4, and a V-groove (V-groove depth T Si Etching was stopped when a thickness of 21 μm was achieved.

[0132] [Table 3]

[0133] [Table 4]

[0134] Thermal oxidation was performed to form another oxide film on the wet-etched surface. Then, to remove all of the nitride film, nitride film etching was performed using hot phosphoric acid under the conditions shown in Table 5.

[0135] [Table 5]

[0136] After that, a second wet etching was performed under the conditions in Table 4, and a V-groove (V-groove depth T Si Etching was stopped when a thickness of 21 μm was achieved. Finally, the oxide film was etched to complete the three-dimensional Si pyramid structure. Each pyramid was arranged in a staggered pattern.

[0137] The above process allows for the fabrication of 68 devices on a single wafer, and multiple wafers can be handled simultaneously.

[0138] Furthermore, a guide structure could be fabricated even when the dimensions of mask #1 (W1), mask #2 (W2-W4), and V-groove depth were set to the conditions in Table 6 (the conditions other than those in Table 6 were the same as in the above example). Chip number 5 corresponds to the above example.

[0139] [Table 6] [Industrial Applicability]

[0140] The guide structure of the present disclosure can be used to guide electromagnetic waves (especially X-rays). For example, the guide structure of the present disclosure can be applied to X-ray flat panel detectors and the like, and can be applied in fields other than medical use as well as non-destructive testing fields such as baggage inspection and maintenance. [Explanation of symbols]

[0141] 1 Guide structure 2 bottom 3 Top 4 electron 10 Substrate 101 First exposed part 101U First recess 1011 Recess protection film 102 Second exposed part 102U Second recess 11 First protective film 11R First Resist 12 Second protective film 12R Second Resist 121 Multiple Openings 21 The First Mask 211 first mask pattern unit 212 multiple openings in the first mask 22 The Second Mask 221 Multiple openings in the second mask 222 Second mask pattern section 30 Electromagnetic Waves 40 Electronic Devices 41 Sensors D1: the respective spacings between the first mask pattern portions D2: the respective spacing between the openings in the second mask W1 Width of each of the first mask pattern portions W2 Length of the opening in the second mask W3 Width of the opening in the second mask W4: Length of the overlapping area between opening A and opening B

Claims

1. A method for manufacturing a guide structure, the method comprising: forming a plurality of first protective films extending in one direction in parallel with a space therebetween on a substrate; forming a second protective film on the plurality of first protective films and on the substrate; removing a portion of the second protective film on the plurality of first protective films and a portion of the plurality of first protective films in this order to form a plurality of first exposed portions where the substrate is exposed; etching the first exposed portion of the substrate with a first etch to form a first recess; removing all of the second protective films on the substrate to form second exposed portions in which the substrate is exposed in portions not covered by the plurality of first protective films; etching the second exposed portion of the substrate to form a second recess with a second etch; and A method for manufacturing a guide structure, comprising removing all of the first protective film on the substrate.

2. The plurality of first protective films extending in one direction in parallel with a gap therebetween, forming a first protective film to cover the surface of the substrate; forming a plurality of first resists on the first protective film, the first resists extending in one direction and in parallel with each other at intervals; 2. The method for manufacturing a guide structure according to claim 1, wherein the guide structure is formed by removing, of the first protective film, portions of the first protective film that are not covered with the plurality of first resists.

3. The first exposed portion forming a second resist having a plurality of openings on the second protective film after the second protective film is formed; wherein the plurality of openings are located on the plurality of first protective films at intervals, The method for manufacturing a guide structure according to claim 1 , wherein the guide structure is formed by removing a portion of the second protective film and a portion of the first protective film in the openings in this order.

4. The method for manufacturing a guide structure according to claim 3 , wherein the plurality of openings in the second resist are arranged in a lattice pattern or a staggered pattern.

5. The method for manufacturing a guide structure according to claim 1 , wherein the first recesses are arranged in a lattice pattern or a staggered pattern.

6. After forming the first recess and before forming the second exposed portion, forming a recess protection film in the first recess; The method for manufacturing a guide structure according to claim 1 , wherein the second exposed portion is a portion where the plurality of first protective films and the recess protective film are not present.

7. The method for manufacturing a guide structure according to claim 1 , wherein the first recess and the second recess have a V-shaped groove structure.

8. The method for manufacturing a guide structure according to claim 1 , wherein the first protective film is an oxide film.

9. The method for manufacturing a guide structure according to claim 1 , wherein the second protective film is a nitride film.

10. A guide structure for guiding electromagnetic waves, the guide structure having a plurality of columnar protrusions.

11. The guide structure according to claim 10 , wherein the plurality of columnar protrusions are arranged in a lattice pattern or a staggered pattern.

12. The guide structure according to claim 10 , wherein the upper surfaces of the plurality of columnar protrusions are flush with each other.

13. The guide structure according to claim 10 , wherein the columnar shape is a frustum shape.

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