Method for forming patterned insulating resin film, method for producing electronic components, and photosensitive film

Abstract

This method forms an insulating resin film having a pattern that contains a through hole and a recess, wherein the method comprises: preparing a photosensitive layer containing a first resin layer and a second resin layer stacked in this order; irradiating, within the photosensitive layer, a region corresponding to the recess, etc., with a second active light; irradiating, within the photosensitive layer, a region corresponding to the through hole, or a region different therefrom, with a first active light; and forming a patterned insulating resin film by a development that collectively removes a part of the first resin layer and a part of the second resin layer. The sensitivity to at least one of the first active light and the second active light is different between the first resin layer and the second resin layer.

Description

Method for forming an insulating resin film having a pattern, method for manufacturing an electronic component, and photosensitive film 【0001】 The present disclosure relates to a method for forming an insulating resin film having a pattern, a method for manufacturing an electronic component, and a photosensitive film. 【0002】 In recent years, with the rapid advancement of high functionality in electronic devices represented by AI / HPC, etc., the increase in size and density of semiconductor packages has been accelerating. Regarding the structure of semiconductor packages, not only the density of surface mounting has increased, but also the technology of inorganic (silicon) interposers or organic interposers (Bridge die / RDL), and 2.xD mounting and 3D mounting technology (HBM / Chiplet) using the same, have led to the complexity and diversification of the mounting process. For example, Resonac Co., Ltd. is mainly based on the "Packaging Solution Center" and is engaged in the technological development of the next-generation semiconductor packaging process from the perspective of customers (semiconductor manufacturers) by combining the mounting process and materials. 【0003】 In an electronic component such as a fan-out type semiconductor package, generally, a wiring layer including fine wirings formed in an organic insulating layer is provided. As a method for forming the wiring layer, a damascene method may be adopted, which includes forming a concave portion on the surface of an insulating material layer and forming a conductor layer constituting the wiring in the concave portion by plating (for example, Patent Document 1). 【0004】 International Publication No. 2024 / 142742 【0005】 In order to form a fine multilayer wiring layer, in addition to the portions constituting the wiring portions of each layer, a complex process including forming an insulating resin film having concave portions with different depths is often required to form a conductor layer including portions connecting between layers. The present disclosure relates to a method capable of forming a fine wiring layer including an insulating resin film having through holes and concave portions with a simpler process. 【0006】This disclosure includes: [1] an insulating resin film having a pattern, wherein the pattern includes through holes penetrating the insulating resin film and recesses having a depth less than the thickness of the insulating resin film, the method comprising: preparing a photosensitive layer comprising a first resin layer and a second resin layer, which are laminated in this order; irradiating the photosensitive layer with a second active ray to a portion of the photosensitive layer corresponding to the recesses or other portions, or to a portion of the through holes and the recesses or other portions; irradiating the photosensitive layer with a first active ray containing light of a different wavelength than the wavelength of the second active ray to a portion of the photosensitive layer corresponding to the through holes or other portions; and forming the insulating resin film having the pattern by developing, which removes a portion of the first resin layer and a portion of the second resin layer together, wherein the through holes are formed by removing a portion of the first resin layer and a portion of the second resin layer by developing, and the recesses are formed by removing a portion of the second resin layer by developing. [1] A method wherein the sensitivity of the first resin layer and the second resin layer to at least one of the first active ray or the second active ray is different. [2] The method according to [1], wherein the first active ray is an h-ray and the second active ray is an i-ray, or the first active ray is an i-ray and the second active ray is an h-ray. [3] The method according to [1] or [2], wherein the first resin layer and the second resin layer are positive-type photosensitive resin layers, the first active ray is irradiated onto a portion of the photosensitive layer corresponding to the through hole, the second active ray is irradiated onto a portion of the photosensitive layer corresponding to the recess, or the portion of the through hole and the recess, and the sensitivity of the first resin layer to the second active ray is lower than the sensitivity of the second resin layer.[4] The method according to [1] or [2], wherein the first resin layer and the second resin layer are negative-type photosensitive resin layers, the first active ray is irradiated onto a portion of the photosensitive layer other than the portion corresponding to the through-hole, the second active ray is irradiated onto a portion of the photosensitive layer other than the portion corresponding to the through-hole and the recess, and the sensitivity of the first resin layer to the first active ray is higher than the sensitivity of the second resin layer. [5] A method for manufacturing an electronic component, comprising: forming an insulating resin film having a pattern by any one of the methods according to [1] to [4], wherein the pattern includes through-holes penetrating the insulating resin film and recesses having a depth less than the thickness of the insulating resin film; and forming a conductor layer in the through-hole and the recess, thereby forming a wiring layer including the insulating resin film and the conductor layer. [6] A photosensitive film comprising a photosensitive layer, wherein the photosensitive layer comprises a first resin layer and a second resin layer, which are laminated in that order, the first resin layer and the second resin layer are positive-type photosensitive resin layers, and the sensitivity of the first resin layer to at least one of the h-line or i-line is lower than the sensitivity of the second resin layer. [7] A photosensitive film comprising a photosensitive layer, wherein the photosensitive layer comprises a first resin layer and a second resin layer, which are laminated in that order, the first resin layer and the second resin layer are negative-type photosensitive resin layers, and the sensitivity of the first resin layer to at least one of the h-line or i-line is higher than the sensitivity of the second resin layer. 【0007】 A fine wiring layer, including an insulating resin film having through holes and recesses, can be formed using a simpler process. 【0008】Figures 1(a) and 1(b) are process diagrams showing examples of methods for forming an insulating resin film. Figures 2(a) and 2(b) are process diagrams showing examples of methods for forming an insulating resin film. Figure 3 is a process diagram showing an example of a method for forming an insulating resin film. Figures 4(a) and 4(b) are process diagrams showing examples of methods for forming an insulating resin film. Figures 5(a) and 5(b) are process diagrams showing examples of methods for forming an insulating resin film. Figures 6(a) and 6(b) are process diagrams showing examples of methods for manufacturing electronic components. Figure 7 is an electron microscope image of the insulating resin film after development. Figure 8 is an electron microscope image of the insulating resin film after development. 【0009】 The present invention is not limited to the following examples. In the following description, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions may be omitted. Unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the illustrations. The term "layer" is used to include not only the structure of the shape formed on the entire surface when observed as a plan view, but also the structure of the shape formed on a part of it. 【0010】 Figures 1, 2, and 3 are process diagrams illustrating an example of a method for forming an insulating resin film. The method shown in Figures 1 to 3 includes preparing a photosensitive film 2 as shown in Figure 1(a), which comprises a photosensitive layer 20 having a first resin layer 21p and a second resin layer 22p, and forming an insulating resin film 20A as shown in Figure 3 on a substrate 1, which has a pattern including through holes 31 and recesses 32. The first resin layer 21p and the second resin layer 22p constituting the photosensitive layer 20 are each positive-type photosensitive resin layers. 【0011】The insulating resin film 20A shown in Figure 3 may include a first insulating layer 21A formed from a first resin layer 21 and a second insulating layer 22A formed from a second resin layer 22. However, a clear interface does not need to be formed between the first insulating layer 21A and the second insulating layer 22A. The first insulating layer 21A and the second insulating layer 22A are laminated in this order from the substrate 1 side and each has an opening. The through hole 31 is formed by connecting the opening of the first insulating layer 21A and a part of the opening of the second insulating layer 22A. The through hole 31 is provided at a position corresponding to a via portion that electrically connects the wiring layer having the insulating resin film 20A to an adjacent wiring layer, etc., when a multilayer wiring layer including the insulating resin film 20A is formed. The recess 32 is an opening that penetrates the second insulating layer 22A and has a depth smaller than the thickness of the insulating resin film 20A. In other words, the recess 32 is formed from the surface of the insulating resin film 20A on the second insulating layer 22A side to an intermediate position in the thickness direction of the insulating resin film 20A, without penetrating the insulating resin film 20A. The recess 32 may have a pattern corresponding to a designed circuit, including trenches that extend linearly in a plane parallel to the main surface of the substrate 1. 【0012】 The photosensitive layer 20 of a pre-prepared photosensitive film 2 can be laminated onto the substrate 1 as shown in Figure 1(b). The photosensitive film 2 may further have a support film, and the photosensitive layer 20 may be provided on the support film. The first resin layer 21p and the second resin layer 22p may be prepared separately, and the first resin layer 21p and the second resin layer 22p may be laminated on the substrate 1 in this order. Alternatively, the first resin layer 21p and the second resin layer 22p may be formed sequentially on the substrate 1 by applying and drying varnish. 【0013】The first resin layer 21p and the second resin layer 22p can each be formed using a positive-type photosensitive resin composition containing a photosensitive substance, which is commonly used to form insulating resin films constituting wiring layers or rewiring layers of electronic components such as semiconductor packages by photolithography. For example, the positive-type photosensitive resin composition, and the first resin layer 21p and second resin layer 22p formed therefrom, may be so-called dissolution-inhibiting materials containing a polymer material and a dissolution inhibitor that is a photosensitive substance. The polymer material may include, for example, a phenol novolac resin. The dissolution inhibitor may include, for example, a diazonaphthoquinone compound. The photosensitive resin composition may be a polyimide-based material, and examples include a combination of polyhydroxyamide and a diazonaphthoquinone diazide compound, and a combination of partially esterified polyamic acid and a diazonaphthoquinone diazide compound. The positive-type photosensitive resin composition may contain a photoacid generator as the photosensitive substance. 【0014】 The thickness of the first resin layer 21p may be, for example, 0.5 μm or more and 15 μm or less. The thickness of the second resin layer 22p may be, for example, 0.5 μm or more and 15 μm or less. 【0015】 The base material 1 can be any member that supports the wiring layer containing the insulating resin film 20A. The base material 1 may be a member that includes the wiring layer. The base material 1 may include a semiconductor chip or a semiconductor wafer. The base material 1 may be a member that includes a temporary fixing material capable of temporarily holding the wiring layer containing the insulating resin film. 【0016】An insulating resin film 20A can be formed by a method that includes, after a photosensitive layer 20 is provided on the substrate 1, irradiating the portion of the photosensitive layer 20 corresponding to the through-hole 31 and the portion corresponding to the recess 32 with a second active light hν2, as shown in Figure 2(a), irradiating the portion of the photosensitive layer 20 corresponding to the through-hole 31 with a first active light hν1, as shown in Figure 2(b), and developing to remove a portion of the first resin layer 21p and a portion of the second resin layer 22p together, thereby forming an insulating resin film 20A having a pattern including the through-hole 31 and the recess 32. By removing the portion 21h of the first resin layer 21p corresponding to the through-hole 31 by development, a first insulating layer 21A having an opening is formed. By removing the portion of the second resin layer 22p corresponding to the through-hole 31 and the portion 22h corresponding to the recess 32 by development, a second insulating layer 22A having an opening that forms the through-hole 31 and the recess 32 is formed. 【0017】 By irradiating the photosensitive layer 20 with the second active ray hν2 from the second resin layer 22p side through a mask 62 having openings corresponding to the positions of the through holes 31 and recesses 32, the portion of the photosensitive layer 20 corresponding to the through holes 31 and recesses 32 is exposed with the second active ray hν2. By irradiating the photosensitive layer 20 with the first active ray hν1 from the second resin layer 22p side through a mask 61 having openings corresponding to the position of the through holes 31, the portion of the photosensitive layer 20 corresponding to the position of the through holes 31 is exposed with the first active ray hν1. Instead of using a mask, the first active ray hν1 and / or the second active ray hν2 may be irradiated onto the photosensitive layer 20 by direct drawing. The order of irradiation with the first active ray hν1 and the second active ray hν2 can be changed arbitrarily. The photosensitive layer 20 may be irradiated with the first active ray hν1 first, and then with the second active ray hν2. The first active ray hν1 and the second active ray hν2 may be irradiated from the first resin layer 21p side. The second active ray hν2 may not be irradiated to the portion corresponding to the through hole 31, but rather to the portion corresponding to the recess 32. 【0018】In the examples shown in Figures 1-3, the sensitivity of the first resin layer 21p to the second active light hν2 is lower than that of the second resin layer 22p. Therefore, when irradiated with the second active light hν2, the photoreaction of the second resin layer 22p can be selectively promoted while suppressing the progress of the photoreaction of the first resin layer 21p. By irradiating with the first active light hν1, which contains light of a different wavelength than the second active light hν2 and promotes the photoreaction in the first resin layer 21p, the photoreaction of the first resin layer 21p can be sufficiently promoted in the portion of the photosensitive layer 20 corresponding to the through-holes 31. Through such a two-stage exposure, an insulating resin film 20A having a fine pattern including through-holes and recesses can be easily formed in fewer steps. An insulating resin film having a pattern including through-holes and recesses can also be formed in fewer steps by so-called grayscale exposure, in which a single photosensitive layer is exposed with active light so that the exposure amount differs depending on the position. However, in the case of grayscale exposure, the depth of the recesses tends to be particularly difficult to stabilize. Also, recesses with a semicircular bottom surface are easily formed. According to the two-stage exposure method described herein, a recess 32 having a regular rectangular cross-sectional shape and a stable depth can be easily formed by irradiating the second resin layer 22p with a second active ray hν2 that exhibits sufficient sensitivity. 【0019】 Here, "the sensitivity of the first resin layer 21p to the second active light hν2 is lower than the sensitivity of the second resin layer 22p" means that the minimum exposure of the second active light hν2 required to convert the first resin layer 21p to a state where it can be removed by development is greater than the minimum exposure of the second active light hν2 required to convert the second resin layer 22p to a state where it can be removed by development. The sensitivities of the first resin layer 21p and the second resin layer 22p can be adjusted by conventional methods that are commonly applied by those skilled in the art. For example, the sensitivity can be adjusted by the type and amount of photosensitive material (e.g., dissolution inhibitor, photoacid generator) and the type and amount of reaction inhibitor so that the sensitivity of the first resin layer 21p to the second active light hν2 is lower than the sensitivity of the second resin layer 22p to the second active light hν2. Multiple types of commercially available photosensitive films having positive-type photosensitive resin layers with different wavelengths exhibiting high sensitivity may be combined. 【0020】The first active ray hν1 and the second active ray hν2 may be ultraviolet light. The second active ray hν2 mainly contains light of a wavelength that promotes the photoreaction in the second resin layer 22p. However, the second active ray hν2 may also promote the photoreaction in the first resin layer 21p to some extent. The first active ray hν1 is light that mainly promotes the photoreaction in the first resin layer 21p and contains light of a different wavelength than the second active ray hν2. The first active ray hν1 may also promote the photoreaction in the second resin layer 22p. For example, the first active ray hν1 may be an h-ray with a wavelength of 405 nm and the second active ray hν2 may be an i-ray with a wavelength of 365 nm. Alternatively, the first active ray hν1 may be an i-ray and the second active ray hν2 may be an h-ray. When the second active ray hν2 is an h-ray, the sensitivity of the first resin layer 21p to the h-ray may be less than the sensitivity of the second resin layer 22p to the h-ray. When the second active ray hν2 is an i-ray, the absorbance of the first resin layer 21p for the i-ray may be smaller than the absorbance of the second resin layer 22p for the i-ray. 【0021】 After exposure with the first active light hν1 and the second active light hν2, a portion of the first resin layer 21p and a portion of the second resin layer 22p are removed collectively by development, thereby forming the insulating resin film 20A shown in Figure 3. Development includes, for example, supplying a developer onto the photosensitive layer 20. The portion 21h corresponding to the through-holes 31 of the first resin layer 21p and the portion 22h corresponding to the through-holes 31 and recesses 32 of the second resin layer 22p are removed by dissolving in the developer. 【0022】 Examples of development methods using a developer include shower development, spray development, immersion development, and paddle development. The insulating resin film 20A after development may be washed with water or the like. The developer may be an alkaline aqueous solution. The alkaline aqueous solution may contain one or more bases selected from sodium carbonate, sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, ethylamine, diethylamine, triethylamine, triethanolamine, and tetramethylammonium hydroxide (TMAH). The concentration of the base in the alkaline aqueous solution may be 0.1 to 10% by mass based on the mass of the alkaline aqueous solution. The developer may contain alcohol or a surfactant. 【0023】 After development, the insulating resin film 20A may be heated as needed to promote the curing of the first insulating layer 21A and / or the second insulating layer 22A. 【0024】 In the formed insulating resin film 20A, the minimum width of the through-hole 31 (the minimum width in the direction perpendicular to the thickness direction of the insulating resin film 20A) may be, for example, 0.3 μm or more and 10 μm or less, or 1.0 μm or more and 5.0 μm or less. The minimum width of the recess 32 (the minimum width in the direction perpendicular to the thickness direction of the insulating resin film 20A) may be, for example, 0.3 μm or more and 10 μm or less, or 1.0 μm or more and 5.0 μm or less. The maximum depth of the recess 32 may be, for example, 0.5 μm or more and 15.0 μm or less. The maximum depth of the recess 32 may be substantially the same as the thickness of the second resin layer 22p. 【0025】 Figures 4 and 5 are process diagrams showing another example of a method for forming an insulating resin film. The insulating resin film 20A of Figure 3 can also be formed by the methods of Figures 4 and 5. In this example, a photosensitive film 2 having a photosensitive layer 20 composed of a first resin layer 21n and a second resin layer 22n is prepared (Figure 4(a)). The first resin layer 21n and the second resin layer 22 are negative-type photosensitive resin layers. The thicknesses of the first resin layer 21n and the second resin layer 22n can be the same as the thicknesses of the first resin layer 21p and the second resin layer 22p, respectively. Next, as shown in Figure 4(b), the photosensitive layer 20 having the first resin layer 21n and the second resin layer 22n is provided on the substrate 1. As with the example in Figure 1, the method of providing the photosensitive layer 20 on the substrate 1 is not limited to the method using the photosensitive film 2. 【0026】The first resin layer 21n and the second resin layer 22n can each be formed using a negative-type photosensitive resin composition containing a photosensitive substance, which is commonly used to form insulating resin films constituting wiring layers or rewiring layers of electronic components such as semiconductor packages by photolithography. For example, the negative-type photosensitive resin composition, and the first resin layer 21n and the second resin layer 22n formed therefrom, may contain a photopolymerizable monomer, a photopolymerization initiator, and a sensitizer. The photopolymerizable monomer may be a compound having an acrylic group or a methacrylic group. The negative-type photosensitive resin composition, and the first resin layer 21n and the second resin layer 22n formed therefrom, may contain polyimide. The negative-type photosensitive resin composition, and the first resin layer 21n and the second resin layer 22n formed therefrom, may contain a photoacid generator. 【0027】 As shown in Figure 5(a), the photosensitive layer 20 is irradiated with the second active ray hν2 through a mask 64 having openings in areas other than those corresponding to the through holes 31 and recesses 32. Subsequently, as shown in Figure 5(b), the photosensitive layer 20 is irradiated with the first active ray hν1 through a mask 63 having openings in areas other than those corresponding to the through holes 31. The sensitivity of the first resin layer 21n to the first active ray hν1 is higher than that of the second resin layer 22n. Instead of using a mask, the first active ray hν1 and / or the second active ray hν2 may be irradiated onto the photosensitive layer 20 by direct drawing. 【0028】In the example shown in Figure 5, irradiation with the second active light hν2 causes the portion of the second resin layer 22n other than the portion 22h corresponding to the through-holes 31 and recesses 32 to be converted to a state that will not be removed by development due to the progression of the photoreaction (Figure 5(a)). Irradiation with the second active light hν2 may also cause the photoreaction to proceed in portions of the first resin layer 21n other than those corresponding to the through-holes 31 and recesses 32. Subsequently, irradiation with the first active light hν1 selectively causes the photoreaction in the first resin layer 21n, which has a higher sensitivity to the first active light hν1, to proceed. As a result, the portion of the first resin layer 21n other than the portion 21h corresponding to the through-holes 31 is converted to a state that will not be removed by development. The order of irradiation with the first active light hν1 and the second active light hν2 can be changed arbitrarily. The photosensitive layer 20 may be irradiated with the first active light hν1, and then the photosensitive layer 20 may be irradiated with the second active light hν2. An insulating resin film 20A is formed by development after exposure. 【0029】 Here, "the sensitivity of the first resin layer 21n to the first active light hν1 is higher than the sensitivity of the second resin layer 22n" means that the minimum exposure of the first active light hν1 required to convert the first resin layer 21n into a state that cannot be removed by development is smaller than the minimum exposure of the first active light hν1 required to convert the second resin layer 22n into a state that cannot be removed by development. The sensitivities of the first resin layer 21n and the second resin layer 22n can be adjusted by conventional methods that can be commonly applied by those skilled in the art. For example, the sensitivity can be adjusted by the type and amount of photosensitive material (e.g., photoacid generator, sensitizer, photopolymerization initiator) and the type and amount of reaction inhibitor so that the sensitivity of the first resin layer 21n to the first active light hν1 is greater than the sensitivity of the second resin layer 22n to the first active light hν1. Multiple types of commercially available photosensitive films having negative-type photosensitive resin layers with different wavelengths exhibiting high sensitivity may be combined. 【0030】 Apart from the above, the methods shown in Figures 4 and 5 can be the same as the examples in Figures 1 to 3. By this method as well, a recess 32 having a regular rectangular cross-sectional shape and a stable depth can be easily formed in a small number of steps. 【0031】Figure 6 is a process diagram showing an example of a method for manufacturing an electronic component having a wiring layer including an insulating resin film formed by the methods exemplified above. The method shown in Figure 6 includes forming a conductor layer 40 having a maximum thickness greater than the thickness of the insulating resin film 20A and covering the entire insulating resin film 20A, as shown in Figure 6(a), and then forming a conductor layer 40 including via portions 41 and wiring portions 42 by removing a portion of the conductor layer 40 from the side opposite to the substrate 1, as shown in Figure 6(b). The via portions 41 fill through holes 31. The wiring portions 42 fill recesses 32. By this method, an electronic component 100 having a wiring layer 5 composed of an insulating resin film 20A and a conductor layer 40 is manufactured. 【0032】 The conductive material constituting the conductive layer 40 may include metals such as copper and nickel. The conductive layer 40 containing metal can be formed by conventional methods applied to form wiring layers. For example, the conductive layer 40 may be formed by a method that includes forming a seed layer on the insulating resin film 20A by electroless plating and forming an electroplated layer on the seed layer by electroplating. 【0033】 The method for removing a portion of the conductor layer 40 can be a conventional method such as chemical mechanical polishing. The conductor layer 40 may be removed until a generally flat surface is formed between the insulating resin film 20A and the conductor layer 40. 【0034】 By repeating the formation of the wiring layer 5 two or more times as necessary, an electronic component having multiple wiring layers can be obtained. 【0035】 An apparatus for manufacturing an electronic component having a wiring layer, which includes forming an insulating resin film, comprises, for example, a holding unit for holding a structure having a photosensitive layer 20, an exposure apparatus including a first light source that emits a first active ray hν1 and a second light source that emits a second active ray hν2 that includes light having a different wavelength from the wavelength of the first active ray hν1, and a developing apparatus including a supply unit for supplying a developing solution. 【0036】Verification Example Below is an experimental example verifying the formation of an insulating resin film by two-stage exposure. 1. Photosensitive Film A commercially available photosensitive film was prepared having two types of negative-type photosensitive resin layers, #1 or #2, with different sensitivities to h-rays. Photosensitive resin layers #1 and #2 have high sensitivity to i-rays. The sensitivity of photosensitive resin layer #1 to h-rays is higher than that of photosensitive resin layer #2 to h-rays. Photosensitive resin layer #1 (thickness: 15 μm) Photosensitive resin layer #2 (thickness: 7 μm) 【0037】 2. Formation of through-holes (openings for vias) A test substrate was prepared, consisting of a silicon wafer and a Cu film formed on the silicon wafer by sputtering. A two-layer photosensitive layer was formed on the Cu film of this substrate, with photosensitive resin layer #1 as the lower layer (first resin layer) and photosensitive resin layer #2 as the upper layer (second resin layer). The formed photosensitive layer was irradiated with i-rays through a mask having a circular opening with a diameter of 10 μm. The exposure dose was 200 mJ / cm². ２ The photosensitive layer after exposure was developed using a 1% by mass aqueous sodium carbonate solution as the developer. Development formed an insulating resin film with through-holes. A cross-section of the insulating resin film containing the through-holes was formed and observed with an electron microscope. Figure 7 is an electron microscope image of the insulating resin film after development. It was confirmed that through-holes are formed in the insulating resin film by exposure and development of a photosensitive layer composed of two resin layers with different sensitivities. 【0038】3. Formation Test of Recesses (Openings for Wiring) Similar to the through-hole formation test, a two-layer photosensitive layer was formed on the Cu film of the substrate, with photosensitive resin layer #1 as the lower layer (first resin layer) and photosensitive resin layer #2 as the upper layer (second resin layer). The entire surface of the photosensitive layer was irradiated with h-rays (first active light). Subsequently, the photosensitive layer was irradiated with i-rays (second active light) through a mask having openings corresponding to a linear pattern of L / S = 5 μm / 5 μm. The photosensitive layer after exposure was developed using a 1% by mass aqueous sodium carbonate solution as the developer. Development formed an insulating resin film with trenches, which are linear recesses. A cross-section of the insulating resin film containing the recesses was formed, and that portion was observed with an electron microscope. Figure 8 is an electron microscope image of the insulating resin film after development. It was confirmed that exposure and development of a photosensitive layer composed of two resin layers with different sensitivities resulted in the formation of a linear recess in the portion corresponding to the upper photosensitive resin layer #2. 【0039】 1...Substrate, 2...Photosensitive film, 5...Wiring layer, 20...Photosensitive layer, 20A...Insulating resin film, 21n, 21p...First resin layer, 22n, 22p...Second resin layer, 21A...First insulating layer, 22A...Second insulating layer, 21h...Part corresponding to through hole, 22h...Part corresponding to recess, 31...Through hole, 32...Recess, 40...Conducting layer, 41...Via part, 42...Wiring part, 100...Electronic component, hν1...First active ray, hν2...Second active ray.

Claims

1. A method for forming an insulating resin film having a pattern, wherein the pattern includes through holes penetrating the insulating resin film and recesses having a depth less than the thickness of the insulating resin film, the method comprising: preparing a photosensitive layer including a first resin layer and a second resin layer, which are laminated in this order; irradiating a portion of the photosensitive layer corresponding to the recesses or other portions, or a portion of the photosensitive layer corresponding to the through holes and the recesses or other portions, irradiating a portion of the photosensitive layer corresponding to the through holes or other portions with a first active light containing light of a different wavelength than the wavelength of the second active light; and forming the insulating resin film having the pattern by developing, which removes a portion of the first resin layer and a portion of the second resin layer together, wherein the through holes are formed by removing a portion of the first resin layer and a portion of the second resin layer by developing, the recesses are formed by removing a portion of the second resin layer by developing, and the sensitivity to at least one of the first active light or the second active light is different between the first resin layer and the second resin layer.

2. The method according to claim 1, wherein the first active ray is an h-ray and the second active ray is an i-ray, or the first active ray is an i-ray and the second active ray is an h-ray.

3. The method according to claim 1, wherein the first resin layer and the second resin layer are positive-type photosensitive resin layers, the first active light is irradiated onto a portion of the photosensitive layer corresponding to the through hole, the second active light is irradiated onto a portion of the photosensitive layer corresponding to the recess, or the portion corresponding to both the through hole and the recess, and the sensitivity of the first resin layer to the second active light is lower than the sensitivity of the second resin layer.

4. The method according to claim 1, wherein the first resin layer and the second resin layer are negative-type photosensitive resin layers, the first active light is irradiated onto a portion of the photosensitive layer other than the portion corresponding to the through hole, the second active light is irradiated onto a portion of the photosensitive layer other than the portion corresponding to the through hole and the recess, and the sensitivity of the first resin layer to the first active light is higher than the sensitivity of the second resin layer.

5. A method for manufacturing an electronic component, comprising: forming an insulating resin film having a pattern, wherein the pattern includes through holes penetrating the insulating resin film and recesses having a depth less than the thickness of the insulating resin film; and forming a conductor layer in the through holes and in the recesses, thereby forming a wiring layer including the insulating resin film and the conductor layer.

6. A photosensitive film comprising a photosensitive layer, wherein the photosensitive layer includes a first resin layer and a second resin layer, which are laminated in this order, the first resin layer and the second resin layer are positive-type photosensitive resin layers, and the sensitivity of the first resin layer to at least one of h-lines or i-lines is lower than the sensitivity of the second resin layer.

7. A photosensitive film comprising a photosensitive layer, wherein the photosensitive layer includes a first resin layer and a second resin layer, which are laminated in this order, the first resin layer and the second resin layer are negative-type photosensitive resin layers, and the sensitivity of the first resin layer to at least one of the h-line or i-line is higher than the sensitivity of the second resin layer.

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