JP5589283B2 - Wiring board and manufacturing method thereof - Google Patents

Description

  The present invention relates to a wiring board and a manufacturing method thereof, and more particularly to a multilayer wiring board having a built-in resistance element and a manufacturing method thereof.

  In order to realize high performance, high functionality, miniaturization and thinning of electronic equipment, for example, a thin film resistor element is formed on a semiconductor substrate or glass substrate for a multilayer wiring substrate for mounting a semiconductor device. However, technology development for integration is underway. However, when the multilayer wiring board on which the thin film resistance element is formed is used in a circuit that allows a large current to flow, such as a power supply circuit, there is a problem that the resistance value fluctuates due to Joule heat generated in the thin film resistance element. Therefore, for example, Patent Document 1 and Patent Document 2 disclose a method for dissipating Joule heat generated in a thin film resistance element.

  A semiconductor integrated circuit device described in Patent Document 1 has a resistor made of a polycrystalline silicon film formed on an insulating film made of an inorganic film on a semiconductor substrate, and metal wiring as electrodes on both sides of the resistor And a metal film for heat dissipation is provided on the resistor via an insulating film.

  A semiconductor integrated circuit device described in Patent Document 2 is formed by forming a resistance layer on an insulating film on a surface of a semiconductor substrate, a thick insulating film selectively formed on the surface of the semiconductor substrate, and a semiconductor substrate And a thin insulating film formed in a region sandwiched between thick insulating films on the surface, and the resistance layer is formed over each region of the thick insulating film and the thin insulating film.

JP-A-62-108567 JP 2001-257317 A

  The following analysis is given from the perspective of the present invention.

  In order to increase the capacity of current flowing in a circuit having a thin film resistor, electromigration is unlikely to occur in the material of the wiring body in order to suppress disconnection failure due to electromigration of the wiring body formed in the same layer as the heat dissipation wiring body. At least one of using a material and increasing the cross-sectional area of the wiring body perpendicular to the direction of the current flowing in the wiring body is required.

  When taking measures to increase the cross-sectional area of the wiring body, the thickness of the wiring body is at most 1 μm, so the width of the wiring body is widened. However, when the insulating film is formed of an inorganic film as in the semiconductor integrated circuit device described in Patent Document 1, for example, the thickness is at most 1 μm. Therefore, in the semiconductor integrated circuit device described in Patent Document 1, when the width of the metal wiring formed in the same layer as the heat dissipation metal film is increased, the parasitic capacitance through the insulating film between the substrate and the metal wiring increases. As a result, there arises a problem that loss in high frequency characteristics increases. Similarly, in the semiconductor integrated circuit device described in Patent Document 2, the increase in the thickness of the oxide film is limited, and it is difficult to reduce the parasitic capacitance.

  On the other hand, when an organic resin is used as the insulating film, it can be easily formed thicker than the inorganic film. Therefore, by adjusting the viscosity of the precursor solution of the organic resin, the film thickness can be changed from several μm to several tens of μm, so the substrate by widening the width of the wiring body formed in the same layer as the heat dissipation wiring body And increase the parasitic capacitance. However, the thickness between the thin film resistor and the heat dissipating wiring body is increased, resulting in a problem that heat cannot be effectively dissipated.

  An object of the present invention is to provide a wiring board that efficiently dissipates heat generated in a resistance element, and a manufacturing method thereof.

According to a first aspect of the present invention, a resistance film, a resistance element having a conductive thin film having a light reflectance different from that of the resistance film, an insulating layer formed in contact with the resistance element, and the resistance element and the electrical resistance There is provided a wiring board comprising: a conductive wiring layer connected to the conductive layer; and a heat radiating wiring layer that radiates heat generated in the resistance element. The insulating layer has a through-hole formed so that the resistance element is exposed, and a concave portion formed so that the bottom portion faces the resistance element and the resistance element is not exposed. The part which forms a through-hole and a recessed part at least among insulating layers is formed from photosensitive resin. The conductive wiring layer is disposed in the through hole. The heat dissipation wiring layer is disposed in the recess. The conductive thin film is formed so as to face the bottom of the through hole or the recess.

According to the second aspect of the present invention, a step of forming a resistance element, a step of forming an insulating layer in contact with the resistance element with a photosensitive resin, a through hole exposing the resistance element in the insulating layer, and a bottom portion having resistance Forming a recess facing the element and not exposing the resistance element in the same process by varying the exposure amount of the area where the through hole is formed and the area where the recess is formed; There is provided a method of manufacturing a wiring board including a step of forming a conductive wiring layer to be connected electrically and a step of forming a heat dissipation wiring layer in a recess.

According to the third aspect of the present invention, the step of forming the heat dissipation wiring layer, the step of forming the first insulating layer covering the heat dissipation wiring layer, and the heat dissipation wiring layer on the first insulating layer Forming a resistive element through the first insulating layer, forming a second insulating layer in contact with the resistive element, forming a through hole exposing the resistive element in the second insulating layer, And forming a conductive wiring layer electrically connected to the resistance element in the hole. In the step of forming the first insulating layer, the first insulating layer is left on the heat dissipating wiring layer by reacting the heat dissipating wiring layer with a part of the precursor layer of the first insulating layer. An insulating layer is formed.

  The present invention has at least one of the following effects.

  According to the present invention, the heat generated in the resistance element can be efficiently radiated. Further, according to the present invention, it is possible to suppress the generation of parasitic capacitance without reducing the heat dissipation effect.

  According to the present invention, the recess and the through hole can be formed by the same process. Further, according to the present invention, a wiring board excellent in heat dissipation and suppression of parasitic capacitance can be manufactured more easily.

1 is a schematic cross-sectional view of a wiring board according to a first embodiment of the present invention. The schematic sectional drawing for demonstrating the manufacturing method of the wiring board which concerns on 1st Embodiment of this invention. The schematic sectional drawing for demonstrating the manufacturing method of the wiring board which concerns on 1st Embodiment of this invention. The schematic sectional drawing for demonstrating the manufacturing method of the wiring board which concerns on 1st Embodiment of this invention. The schematic sectional drawing of the wiring board which concerns on 2nd Embodiment of this invention. The schematic fragmentary sectional view of the recessed part for thermal radiation of the wiring board which concerns on 2nd Embodiment. The schematic sectional drawing for demonstrating the manufacturing method of the wiring board which concerns on 2nd Embodiment of this invention. The schematic sectional drawing of the wiring board which concerns on 3rd Embodiment of this invention. The schematic fragmentary sectional view of the recessed part for thermal radiation of the wiring board which concerns on 3rd Embodiment. The schematic sectional drawing for demonstrating the manufacturing method of the wiring board which concerns on 3rd Embodiment of this invention. The schematic sectional drawing for demonstrating the manufacturing method of the wiring board which concerns on 3rd Embodiment of this invention. The schematic sectional drawing of the wiring board which concerns on 4th Embodiment of this invention. The schematic sectional drawing for demonstrating the manufacturing method of the wiring board which concerns on 4th Embodiment of this invention. The schematic sectional drawing for demonstrating the manufacturing method of the wiring board which concerns on 4th Embodiment of this invention. The schematic sectional drawing of the wiring board which concerns on 5th Embodiment of this invention. The schematic sectional drawing for demonstrating the manufacturing method of the wiring board which concerns on 5th Embodiment of this invention. The schematic sectional drawing for demonstrating the manufacturing method of the wiring board which concerns on 5th Embodiment of this invention. The schematic sectional drawing of the wiring board which concerns on 6th Embodiment of this invention. The schematic sectional drawing of the wiring board of this invention which shows the example which combined several embodiment.

  The preferable form of the said 1st viewpoint-the 3rd viewpoint is described below.

According to the preferable form of the first aspect, the insulating layer includes the first insulating layer and the second insulating layer formed so that a resistance element is interposed between the first insulating layer and the first insulating layer. The through hole and the recess are formed in the first insulating layer .

  According to the preferable form of the first aspect, the thickness of the first insulating layer is 1 μm to 30 μm.

  According to a preferred form of the first aspect, the wiring board further includes a board in contact with the second insulating layer.

  According to the preferable form of the first aspect, the bottom of the recess faces the center of the current path of the resistance element.

According to the preferred embodiment of the first aspect, the through hole is formed so as to expose the conductive thin film. The resistance film is connected between the conductive thin films. The bottom of the recess faces the resistance film .

  According to a preferred form of the first aspect, the conductive thin film is formed on the resistance film. The bottom of the recess faces the conductive thin film. The through hole is formed so as to expose the resistance film.

  According to the preferred embodiment of the first aspect, the corner formed by the side surface and the bottom surface of the recess is rounded.

According to the preferable form of the first aspect, the conductive thin film of the resistance element contains copper. The precursor of the part which forms a recessed part at least among insulating layers contains a polyamic acid.

  According to a preferred embodiment of the first aspect, the heat dissipation wiring layer contains copper. The precursor of the part which forms a recessed part at least among insulating layers contains a polyamic acid.

  According to the preferable form of the first aspect, the portion of the insulating layer that forms the bottom of the recess contains copper.

  According to the preferable form of the first aspect, the concave portion has at least one convex portion or concave portion at the bottom thereof.

  According to the preferred embodiment of the second aspect, the conductive wiring layer and the heat dissipation wiring layer are formed by the same process.

  According to the preferable form of the second aspect, when the precursor layer of the first insulating layer is exposed, light is transmitted between the first mask that covers the region where the through hole is formed and the second mask that covers the region where the recess is formed. Different rates.

  According to the preferable form of the second viewpoint, the conductive thin film that is a part of the resistance element is formed in the region facing the region where the through hole is formed. A resistance film which is a part of the resistance element and has a light reflectance different from that of the conductive thin film is formed in a region facing the region where the recess is formed. A precursor layer of the first insulating layer is formed on the resistance element, and the precursor layer of the insulating layer is exposed to form a through hole and a recess.

  According to a preferred embodiment of the second aspect, the reaction between the part of the resistance element facing the region where the recess is formed and the part of the precursor layer of the first insulating layer causes the reaction between the recess and the resistance element. 1 The insulating layer is left to form a recess.

  According to a preferred form of the second aspect, the precursor of the insulating layer is a photosensitive resin containing polyamic acid. At least a part of the resistance element contains copper.

According to a preferred form of the third aspect, the precursor of the first insulating layer is a photosensitive resin containing polyamic acid. The heat dissipation wiring layer contains copper.

  A wiring board according to a first embodiment of the present invention will be described. FIG. 1 shows a schematic cross-sectional view of a wiring board according to the first embodiment of the present invention. Although the wiring board of the present invention can be formed as a multilayer wiring board, the wiring board 100 according to the present embodiment shown in FIG. 1 shows only one wiring layer for simplification.

  The wiring substrate 100 includes a substrate 101, a resistance element 103 formed on the substrate 101, a conductive wiring layer 106 electrically connected to the resistance element 103, and a heat dissipation wiring layer formed above the resistance element 103. 107 and a first insulating layer 104 formed on the substrate 101.

  As the substrate 101, for example, a semiconductor substrate, a glass substrate, a ceramic substrate, or the like can be used. The thickness of the substrate 101 can be set to 0.5 mm, for example.

  In the case where the substrate 101 is a low-resistance substrate, an insulating layer is preferably formed over the substrate 101 in order to prevent a change in the resistance value of the resistance element 103. In this embodiment, the second insulating layer 102 is formed on the substrate 101. The second insulating layer 102 may be either an inorganic insulating film or a resin insulating film. For example, a silicon oxide film can be used.

  In the present embodiment, the resistance element 103 is formed on the second insulating layer 102 in the form of a resistance film. As the resistance element 103, a high-resistance thin film conductive film can be used. For example, titanium nitride, tantalum nitride, nichrome (an alloy of nickel and chromium), or the like can be used. The thickness of the resistance element 103 is preferably less than or equal to the thickness of the conductive wiring layer 106, and can be, for example, 1 μm or less. The resistance value of the resistance element 103 is preferably set as appropriate according to the amount of voltage and the amount of current, and is preferably set to be 100Ω or less, for example. The resistance element 103 may be formed from a plurality of thin films, for example, may have a resistance film and a conductive thin film. In this case, it is preferable to dispose the heat dissipation wiring layer 107 so as to dissipate the heat generated in the resistive film that generates more heat.

  A first insulating layer 104 is formed on the second insulating layer 102 and the resistance element 103. The first insulating layer 104 may be either an inorganic insulating film or a resin insulating film, but an organic resin is used so that the layer thickness can be easily adjusted (in particular, it can be formed thick in order to reduce parasitic capacitance). Preferably formed. As the first insulating layer 104, for example, polyimide resin, epoxy resin, BCB (benzocyclobutene) resin, PBO (polybenzoxazole) resin, or the like can be used. The thickness of the first insulating layer 104 is preferably set so as not to be affected by parasitic capacitance, and is preferably set to 1 μm to 30 μm, for example.

  The first insulating layer 104 is formed with a conductive through hole 104a so that the resistance element 103 is exposed. The conductive wiring layer 106 is formed so as to fill the conductive through-hole 104 a and is electrically connected to both ends of the resistance element 103. The conductive wiring layer 106 is preferably formed to be higher than the upper surface of the first insulating layer 104. For example, copper can be used as the conductive wiring layer 106. In this embodiment, the conductive wiring layer 106 is electrically connected to the resistance element 103 through a seed layer 105 for forming the conductive wiring layer 106. The layer thickness of the conductive wiring layer 106 is preferably set so that the current density does not increase, and can be, for example, several μm to 30 μm.

  Further, the first insulating layer 104 has a heat radiation recess or groove (hereinafter referred to as “heat radiation recess”) 104 b so that the bottom portion faces the resistance element 103 and the resistance element 103 is not exposed. The heat radiation wiring layer 107 is formed so as to fill the heat radiation recess 104 b and is not electrically connected to the resistance element 103. The heat dissipation wiring layer 107 is preferably formed to be higher than the upper surface of the first insulating layer 104. For example, copper can be used as the heat dissipation wiring layer 107. In this embodiment, the heat dissipation wiring layer 107 is electrically connected to the resistance element 103 through the seed layer 105 for forming the heat dissipation wiring layer 107. In the cross section as shown in FIG. 1, one heat radiating wiring layer 107 is shown, but a plurality of heat radiating wiring layers 107 may be formed for one resistance element 103. Further, the heat radiation wiring layer 107 is preferably formed at a location where the resistance element 103 generates the most heat, and is preferably formed at the center of the current flow path of the resistance element 103, for example. The heat dissipation wiring layer 107 may be thermally connected to the substrate or the outside so as to be able to dissipate heat more efficiently, or may be in a floating state.

The layer thickness t of the first insulating layer 104 that determines the distance between the bottom surface of the heat-dissipating recess 104b of the first insulating layer 104 and the resistance element 103 is preferably set from the viewpoints of heat dissipation and insulation, for example, 0.05 μm to 0 μm. .3 μm. Area bottom and the resistance element 103 of the radiating recess 104b is opposed, from the viewpoint of heat dissipation, can be, for example, 50μm ² ~10,000μm ^2.

  According to the present invention, the thickness of the first insulating layer 104 between the heat dissipation wiring layer 107 and the resistance element 103 can be reduced, and the heat of the resistance element 103 can be efficiently radiated. In addition, the thickness of the first insulating layer 104 between the substrate 101 and the first wiring layer 106 is reduced while the thickness of the first insulating layer 104 between the heat dissipation wiring layer 107 and the resistance element 103 is reduced. Since the thickness of the first insulating layer 104 between the layer 107 and the resistance element 103 can be made thicker, an increase in parasitic capacitance between the substrate 101 and the conductive wiring layer 106 can be suppressed. This also makes it possible to increase the withstand current capacity that can be passed through the resistance element by an order of magnitude compared to the background art.

  Next, an example of the manufacturing method of the wiring board according to the first embodiment of the present invention will be described. 2 to 4 are schematic cross-sectional views for explaining a method of manufacturing a wiring board according to the first embodiment of the present invention.

  First, a silicon oxide film was formed as a second insulating layer 102 on a 0.5 mm thick high resistance silicon substrate 101 (FIG. 2A). Next, after cleaning the second insulating layer 102, it is introduced into a DC sputtering apparatus, and after reaching a desired degree of vacuum, a titanium nitride layer having a thickness of 100 nm is formed as a resistance element precursor layer 103A that is the basis of the resistance element 103. Was deposited on the entire surface of the substrate 101 (FIG. 2B). Next, after forming a photoresist on the entire surface as the mask 111, the mask 111 was formed into a desired pattern by using a photolithography method (FIG. 2C). Next, an unnecessary region of the resistance element precursor layer 103A is removed by dry etching or wet etching, and the desired resistance element 103 is formed by removing the mask 111 by an organic solvent and oxygen plasma treatment (FIG. 2D). ). Next, as a first insulating layer precursor layer 104A that is a base of the first insulating layer 104, a negative photosensitive polyimide resin precursor solution was applied on the entire surface and dried (FIG. 2E). Next, conductive through holes 104a were formed in the first insulating layer precursor layer 104A on the resistance element 103 by exposure and development using the mask 112 and the glass mask 113. After the development, the polyimide resin as the first insulating layer precursor layer 104A is cured by heating and holding in a nitrogen atmosphere to form the first insulating layer 104 having a layer thickness of 10 μm (FIGS. 2 (f) and 3 (3)). g)). Note that the resin of the first insulating layer 104 may be a positive type. In that case, the mask 112 and the glass mask 113 may be interchanged.

  Next, a photoresist was formed as a mask 114 on the entire surface of the first insulating layer 104 and the resistance element 103, and a pattern having a desired shape was formed by photolithography (FIG. 3H). Next, a heat radiating recess 104b was formed in the first insulating layer 104 by dry or wet etching (FIG. 3 (i)), and the mask 114 was removed by organic solvent and oxygen plasma treatment (FIG. 3 (j)). The distance between the bottom surface of the heat radiation recess 104b and the resistance element 103 was set to 0.1 μm. Next, the surfaces of the first insulating layer 104 and the resistance element 103 were cleaned by oxygen plasma treatment, and then introduced into a DC sputtering apparatus. After reaching the desired degree of vacuum, titanium (Ti) and copper (Cu) were sequentially stacked on the entire surface of each of the first insulating layer 104 and the resistance element 103 to form a seed layer 105 (FIG. 3 (k )). In the seed layer 105, the thickness of each component was 50 nm of titanium and 300 nm of copper. Here, copper acts as a power feeding layer in later electrolytic plating. Titanium acts as an adhesion layer for enhancing adhesion between the first insulating layer 104 and the like and copper. The adhesion layer is not limited to titanium, for example, tantalum (Ta), chromium (Cr), molybdenum (Mo), aluminum (Al), nickel (Ni), tungsten (W), or at least of these Compounds containing one may be used.

  Next, a photoresist was formed on the entire surface of the seed layer 105 as a mask 115, and a pattern having a desired shape was formed by photolithography (FIG. 4L). Next, the seed layer 105 was used as a power feeding layer, and copper plating to be a heat radiation wiring layer 107 and a conductive wiring layer 106 was formed on the opening surface of the mask 115 by electrolytic plating so as to have a film thickness of 5 μm (FIG. 4 ( m)). In addition, the formation method of the heat dissipation wiring layer 107 and the conductive wiring layer 106 is not limited to the electrolytic plating method. For example, a formation method using an electroless plating method and wet etching, a formation method using a screen printing method, or the like is used. May be. Next, the mask 115 was removed by an organic solvent and oxygen plasma treatment (FIG. 4 (n)). Next, the unnecessary seed layer 105 was removed by a chemical etching method, and the wiring board 100 was manufactured (FIG. 4O).

  In the case of manufacturing a multilayer wiring board, the above-described steps are repeated to laminate the insulating layer and the wiring layer to form a multilayer wiring board having a built-in resistance element (not shown).

  According to the manufacturing method of this embodiment, the heat radiation wiring layer 107 and the conductive wiring layer 106 having a desired pattern can be formed in a lump.

  A wiring board according to a second embodiment of the present invention will be described. FIG. 5 is a schematic cross-sectional view of a wiring board according to the second embodiment of the present invention. FIG. 6 is a schematic partial cross-sectional view of the heat dissipation recess of the wiring board according to the second embodiment. Note that the wiring substrate 200 shown in FIG. 5 shows only one wiring layer for simplification. 5 and 6, the same elements as those of the first embodiment shown in FIGS.

  The wiring board 200 according to the second embodiment has the same configuration as the wiring board according to the first embodiment, except that the bottom surface of the heat-dissipating recess 204a of the first insulating layer 204 has at least one protrusion ( It is a point which has a recessed part, a collar part, a groove part, or a wave-like part) 204c. Preferably, the bottom surface of the heat-dissipating recess 204b of the first insulating layer 204 has a plurality of protrusions 204c. The pattern formed by the plurality of convex portions 204c can be formed in various patterns such as a grid pattern, a slit pattern, and a dot pattern, for example. In the form shown in FIG. 6, the bottom surface of the heat radiating recess 204b has a wave shape.

  The first insulating layer 204 is preferably formed from a photosensitive resin.

  Next, an example of a method for manufacturing a wiring board according to the second embodiment of the present invention will be described. FIG. 7 is a schematic cross-sectional view for explaining the method for manufacturing a wiring board according to the second embodiment of the present invention.

  First, the first insulating layer precursor layer 204A was formed in the same manner as the steps shown in FIGS. 2A to 2E of the first embodiment. Next, the conductive through-hole 204a and the heat-dissipating recess 204b were formed in the first insulating layer precursor layer 204A using the glass mask 214 (FIGS. 7F and 7G). In the step shown in FIG. 2 (f) of the first embodiment, only the conductive through hole is formed by exposure / development, and then the heat radiating recess is formed by etching. The through hole 204a and the heat radiating recess 204b were formed at the same time.

  The first mask 212 for forming the conductive through hole 204a is the same as the mask in the first embodiment, but in this embodiment, the second mask 213 for forming the heat radiating recess 204b is replaced with the glass mask 214. Is provided. In order to make the depth of the heat radiating recess 204b smaller than the depth of the conductive through hole 204a, the second mask 213 is formed with a through hole for partially adjusting the light transmittance. Thereby, the exposure amount can be adjusted, and the first insulating layer 204 can be left at the bottom of the heat radiation recess 204b. The through hole is preferably a pattern having a size smaller than the resolution of the exposure machine. For example, the second mask 213 can be formed with through holes of various patterns such as a grid pattern, a slit pattern, and a dot pattern. By forming the heat dissipation recesses 204b using the second mask 213, a plurality of protrusions 204c corresponding to the pattern of the through holes were formed on the bottom surface of the heat dissipation recesses 204b.

  The processes after FIG. 7G are the same as the processes shown in FIGS. 3K to 4O of the first embodiment, and the description thereof is omitted here.

  Other aspects of the present embodiment are the same as those of the first embodiment, and a description thereof is omitted here.

  According to this embodiment, the bottom surface of the heat dissipation recess 204b has a large surface area due to the unevenness, and the heat of the resistance element 103 can be radiated more efficiently. Further, the heat-dissipating recess 204b and the conductive through-hole 204a can be formed in the same process, and the number of manufacturing processes can be reduced.

  A wiring board according to a third embodiment of the present invention will be described. FIG. 8 is a schematic sectional view of a wiring board according to the third embodiment of the present invention. FIG. 9 shows a schematic partial cross-sectional view of the heat dissipation recess of the wiring board according to the third embodiment. Note that the wiring board 300 shown in FIG. 8 shows only one wiring layer for simplification. Moreover, in FIG. 8, the same code | symbol is attached | subjected to the same element as 1st Embodiment shown in FIGS.

  In the wiring board 300 according to the third embodiment, the resistance element includes the resistance film 303 and the conductive thin film 106. The conductive thin film 308 is formed under the conductive wiring layer 106, and the resistance film 303 is connected between the conductive thin films 308. The resistance film 303 is electrically connected to the conductive wiring layer 106, and may be electrically connected to the conductive wiring layer 106 through the conductive thin film 308. In the form shown in FIG. 8, the resistance film 303 is formed so as to cover a part on the conductive thin film 308.

  The first insulating layer 304 is preferably formed from a photosensitive resin.

  The resistance film 303 and the conductive thin film 308 have different light reflectivities. For example, for the conductive thin film 308, a conductive material having a light reflectance different from that of the resistance film 303 is selected. When the first insulating layer 304 is formed from a negative-type photosensitive polyimide resin precursor solution, the reflectance of the resistance film 303 is made smaller than that of the conductive thin film 308. For example, when the resistance film 303 is titanium nitride, ruthenium can be used as the conductive thin film 308. When titanium nitride is used, a part of the light is transmitted, so that the heat radiating recess 304 b can be formed by the light scattered in the resistance film 303. The reflectance can be appropriately adjusted by selecting a material, surface roughness, and the like.

  The heat radiation recess 304b has an inclination 304c from the side surface to the bottom surface. The slope 304c has a shape such that a corner formed by the side surface and the bottom surface of the heat radiation recess 304b is rounded. Alternatively, the slope 304c has a shape such that the bottom surface of the heat dissipation recess 304b is deeper toward the center.

  The conductive thin film 308 may be an upper electrode of a thin film capacitor. That is, a thin film capacitor may be built under the conductive wiring layer 106.

  Next, an example of a method for manufacturing a wiring board according to the third embodiment of the present invention will be described. 10 to 11 are schematic cross-sectional views for explaining a method for manufacturing a wiring board according to the third embodiment of the present invention.

  First, in the same manner as the process shown in FIG. 2A of the first embodiment, the second insulating layer 102 was formed on the substrate 101 (FIG. 10A). Next, the surface of the second insulating layer 102 was cleaned and then introduced into a DC sputtering apparatus. After reaching a desired degree of vacuum, a conductive thin film 308 made of ruthenium (Ru) is formed at a predetermined position on the second insulating layer 102 using a mask (for example, a metal mask) 311 (FIG. 10B). The film was formed with a film thickness of 50 nm (FIG. 10C). The conductive thin film 308 may be formed in a desired pattern by photolithography and etching after being formed over the entire surface of the second insulating layer 102. Next, similarly to the first embodiment, a resistive film precursor layer 403A made of titanium nitride is formed (FIG. 10D), a desired resistive film 303 is formed using the mask 312 and the mask 312 is removed. (FIG. 10E). In the above example, the resistive element is formed after forming the conductive thin film. However, the conductive thin film may be formed after forming the resistive element.

  Next, similarly to the first embodiment, a first insulating layer precursor layer 304A was formed using a polyimide resin precursor solution having negative photosensitivity. Next, the first insulating layer precursor layer 304A was exposed using a glass mask 315 having a first mask 313 for forming the conductive through-hole 304a and a second mask 314 for forming the heat-dissipating recess 304b. (FIG. 11 (f)). Here, the conductive thin film 308 made of ruthenium and the resistive film 303 made of titanium nitride have different light reflectivities or light transmittances into the thin film. Therefore, the conductive thin film 308 and the resistive film 303 are different from each other. The optimum exposure amount of the first insulating layer precursor layer 304A is different. Therefore, when exposure is performed with an optimal exposure amount for the first insulating layer precursor layer 304A on the conductive thin film 308, the light below the second mask 314 is caused by light transmitted into the resistance film 303 or light scattered inside the resistance film 303. The portion is also exposed, and the first insulating layer precursor layer 304A on the resistance film 303 is overexposed. Therefore, the reaction also proceeds in the region masked by the second mask 314 by the light from the side (lateral) direction of the second mask 314 or the light scattered by the resistance film 303. As a result, a conductive through hole 304a in which the conductive thin film 308 is exposed is formed in the region of the first insulating layer precursor layer 304A under the first mask 313, and the first insulating layer precursor layer 304A under the second mask 314 is formed. In this region, a heat radiating recess 304b where the resistance film 303 is not exposed is formed (FIG. 11G). Next, similarly to the first embodiment, the seed layer 105, the conductive wiring layer 106, and the heat dissipation wiring layer 107 were formed, and the wiring substrate 300 was formed.

  In the case of using a positive photosensitive resin, the resistance film 303 is made of, for example, ruthenium, and the positions of the resistance film 303 and the conductive thin film 308 are exchanged to form the conductive through hole 304a and the heat radiating recess 304b all together. can do.

  Other aspects of the present embodiment are the same as those of the first embodiment, and a description thereof is omitted here.

  According to the present embodiment, the conductive through hole 304a and the heat radiating recess 304b can be formed in the same process.

  A wiring board according to a fourth embodiment of the present invention will be described. FIG. 12 is a schematic sectional view of a wiring board according to the fourth embodiment of the present invention. Note that the wiring substrate 400 shown in FIG. 12 shows only one wiring layer for simplification. Further, in FIG. 12, the same elements as those in the first embodiment shown in FIGS.

  In the wiring board 400 according to the fourth embodiment, the resistance element includes a resistance film 403 and a conductive thin film 408. The conductive thin film 408 is formed on the resistance film 403 under the heat dissipation wiring layer 107. The conductive thin film 408 and the heat radiation wiring layer 107 (or the seed layer 105) are not in contact with each other, and the first insulating layer 404 is interposed therebetween. The conductive thin film 408 is made of a material that can react with the raw material of the first insulating layer 404 and leave the first insulating layer 404 between the heat sink recess 404b and the conductive thin film 408. For example, when the first insulating layer 404 is formed using a polyimide resin precursor solution containing polyamic acid, a material containing copper (Cu) (for example, a copper film) may be used as the conductive thin film 408. it can.

  The bottom portion of the heat dissipation recess 404b (that is, the first insulating layer 404 portion between the bottom surface of the heat dissipation recess 404b and the conductive thin film 408) contains copper diffused from the conductive thin film 408.

  Next, an example of a method for manufacturing a wiring board according to the fourth embodiment of the present invention will be described. 13 to 14 are schematic cross-sectional views for explaining a method of manufacturing a wiring board according to the fourth embodiment of the present invention.

  First, similarly to the process shown in FIG. 2A of the first embodiment, the second insulating layer 102 was formed on the substrate 101 (FIG. 13A). Next, the surface of the second insulating layer 102 was cleaned and then introduced into a DC sputtering apparatus. After reaching the desired degree of vacuum, a resistance film precursor layer 403A made of titanium nitride is formed on the second insulating layer 102, and then a conductive film having a thickness of 10 nm made of copper is formed on the resistance film precursor layer 403A. The thin film precursor layer 408A was formed (FIG. 13B). Note that the thickness of the conductive thin film precursor layer 408A may be a thickness that does not greatly change the resistance value of the resistance film 403 and can form the first insulating layer 404 that is difficult to dissolve on the conductive thin film 408. For example, 1 nm to 20 nm is preferable. Next, in the same manner as in the above embodiment, the conductive thin film 408 is formed using the mask 411 (FIGS. 13C and 13D), and the resistance film 403 is formed using the mask 412 (FIG. 13 ( e), FIG. 14 (f)). Note that the conductive thin film 408 may be formed over the resistance film 403 using a metal mask. In this case, the conductive thin film 408 may be formed either before or after the pattern formation of the resistance film 403.

  Next, as the first insulating layer precursor layer 404A, a negative photosensitive polyimide resin precursor solution containing polyamic acid was applied on the entire surface and dried. The conductive thin film 408 made of Cu diffuses and reacts with the first insulating layer precursor layer 404A containing polyamic acid to make it difficult to dissolve the first insulating layer precursor layer 404A on the conductive thin film 408. As a result, the conductive through-hole 404a with the resistive film 403 exposed and the heat-dissipating recess 404b with the first insulating layer precursor layer 404A on the conductive thin film 408 remaining and the conductive thin film 408 not exposed are collectively formed. can do. Next, the first insulating layer precursor layer 404A was heated in a nitrogen atmosphere to cure the polyimide resin, thereby forming a first insulating layer 404 having a layer thickness of 10 μm and a thickness of 0.05 μm at the bottom of the heat dissipation recess 404b ( FIG. 14 (g), (h)). Next, in the same manner as in the first embodiment, the seed layer 105, the conductive wiring layer 106, and the heat dissipation wiring layer 107 were formed to form the wiring board 400 (FIG. 14 (i)).

  Other aspects of the present embodiment are the same as those of the first embodiment, and a description thereof is omitted here.

  According to the present embodiment, the conductive through hole 404a and the heat radiating recess 404b can be formed in the same process.

  A wiring board according to a fifth embodiment of the present invention will be described. FIG. 15 is a schematic cross-sectional view of a wiring board according to the fifth embodiment of the present invention. Note that the wiring substrate 500 shown in FIG. 12 shows only one wiring layer for simplification. Further, in FIG. 12, the same elements as those in the first embodiment shown in FIGS.

  In the first embodiment to the fourth embodiment, the conductive wiring layer and the heat dissipation wiring layer are formed on the same side with respect to the resistance element. However, in the wiring substrate 500 according to the fifth embodiment, the conductive wiring layer The wiring layer 106 and the heat radiation wiring layer 507 are formed on the opposite side to the resistance element 103. In the form shown in FIG. 15, the conductive wiring layer 106 is formed on the resistance element 103 as in the first to fourth embodiments, but the heat radiation recess 502 a is formed in the second insulating layer 502. The heat dissipation wiring layer 507 is formed below the resistance element 103 with the second insulating layer 502 interposed therebetween. The heat dissipating wiring layer 507 is preferably disposed at least partly between the conductive wiring layers 106, and more preferably extends along the resistance element 103 between the conductive wiring layers 106. A seed layer 509 for forming the heat dissipation wiring layer 507 by electrolytic plating is formed under the heat dissipation wiring layer 507.

  Next, an example of a method for manufacturing a wiring board according to the fifth embodiment of the present invention will be described. 16 to 17 are schematic cross-sectional views for explaining a method for manufacturing a wiring board according to a fifth embodiment of the present invention.

  First, similarly to the formation of the conductive wiring layer and the heat dissipation wiring layer in the first embodiment, the heat dissipation wiring layer 507 was formed on the substrate 101. First, a seed layer 509 was formed on the substrate 101. Next, a mask 511 was formed at a predetermined position, and a heat radiation wiring layer 507 was formed by electrolytic plating. Next, the mask 511 and the unnecessary seed layer were removed (FIGS. 16A to 16D).

  Next, as the second insulating layer 502, a non-photosensitive polyimide resin precursor solution was applied on the entire surface, dried, and heated in a nitrogen atmosphere to cure the polyimide resin (FIG. 16E). The thickness of the second insulating layer 502 was 10 μm, and the thickness of the second insulating layer 502 on the heat radiation wiring layer 507 was 0.1 μm. In order to enhance heat dissipation, the second insulating layer 502 on the heat dissipation wiring layer 507 may be thinned by mechanical polishing or etching after the second insulating layer 502 is formed.

  Further, like the first insulating layer formation in the fourth embodiment, the heat dissipation wiring layer 507 is formed of a material containing copper, and the second photosensitive polyimide resin precursor solution containing polyamic acid is used to form the second insulating layer. By forming the insulating layer 502, the second insulating layer 502 may be formed so that the second insulating layer 502 on the heat radiation wiring layer 507 remains.

  The other steps are the same as those in the first embodiment except that the heat-radiating recess and the heat-dissipating wiring layer are not formed, and a description thereof is omitted here (FIGS. 17F to 17H).

  Other aspects of the present embodiment are the same as those of the first embodiment, and a description thereof is omitted here.

  According to the present embodiment, the heat dissipation can be adjusted by changing the facing area between the heat dissipation wiring layer and the resistance element.

  A wiring board according to a sixth embodiment of the present invention will be described. FIG. 18 is a schematic cross-sectional view of a wiring board according to the sixth embodiment of the present invention. Note that the wiring substrate 600 shown in FIG. 18 shows only one wiring layer for simplification. In FIG. 18, the same elements as those in the first embodiment shown in FIGS. 1 to 4 and the fifth embodiment shown in FIGS. 15 to 17 are denoted by the same reference numerals.

  The wiring board 600 according to the sixth embodiment is the same as the wiring board according to the fifth embodiment, except that a through electrode 609 electrically connected to the heat dissipation wiring layer 507 is formed. It is. The through electrode 609 penetrates the substrate 601 and is thermally connected to the outside. Thereby, the heat transmitted from the resistance element 103 to the heat radiation wiring layer 507 can be radiated more efficiently.

  Other aspects of the present embodiment are the same as those of the first and fifth embodiments, and description thereof is omitted here.

  The wiring board and the manufacturing method thereof according to the present invention have been described based on the first to sixth embodiments, but a plurality of embodiments can be combined. FIG. 19 shows an example of a wiring board obtained by combining a plurality of embodiments. For example, a wiring board that combines the first embodiment, the fifth embodiment, and the sixth embodiment may be formed as a wiring board 700 shown in FIG.

  In the above embodiment, the wiring board having one wiring layer has been described. However, the present invention can also be applied to a multilayer wiring board having a plurality of wiring layers.

  The wiring board and the manufacturing method thereof according to the present invention have been described based on the above embodiment, but are not limited to the above embodiment, and are within the scope of the present invention and based on the basic technical idea of the present invention. It goes without saying that various modifications, changes, and improvements can be included in the embodiment. Further, various combinations, substitutions, or selections of various disclosed elements are possible within the scope of the claims of the present invention.

  Further problems, objects, and developments of the present invention will become apparent from the entire disclosure of the present invention including the claims.

100, 200, 300, 400, 500, 600, 700 Wiring board 101, 601 Substrate 102, 502 Second insulating layer 103 Resistance element 303, 403 Resistance film 103A Resistance element precursor layer 303A, 403A Resistance film precursor layer 104, 204, 304, 404, 504 First insulating layer 104A, 204A, 304A, 404A First insulating layer precursor layer 104a, 204a, 304a, 404a Conductive through hole 104b, 204b, 304b, 404b Heat radiation recess 105 Seed layer 106 Conductive wiring Layer 107 Wiring layer for heat dissipation 111, 312, 412 Mask (photoresist)
112 Mask 113, 214, 315, 415 Glass mask 114, 115, 411 Mask 204c Projection 212, 313, 413 First mask 213, 314, 414 Second mask 304c Inclined 308, 408 Conductive thin film 311 Mask 408A Conductive thin film Precursor layer 502a Heat radiation recess 507 Heat radiation wiring layer 509 Seed layer 609 Through electrode

Claims (20)

A resistive element having a resistive thin film and a conductive thin film having a light reflectance different from that of the resistive film ;
An insulating layer formed in contact with the resistance element;
A conductive wiring layer electrically connected to the resistance element;
A heat dissipation wiring layer that dissipates heat generated in the resistance element, and
The insulating layer has a through hole formed so that the resistance element is exposed, and a recess formed so that the bottom portion faces the resistance element and the resistance element is not exposed,
Of the insulating layer, at least the part that forms the through hole and the recess is formed of a photosensitive resin,
The conductive wiring layer is disposed in the through hole,
The heat dissipation wiring layer is disposed in the recess ,
The wiring substrate, wherein the conductive thin film is formed so as to face the bottom of the through hole or the recess . The insulating layer has a first insulating layer and a second insulating layer formed so as to interpose the resistance element between the first insulating layer,
The wiring substrate according to claim 1, wherein the through hole and the recess are formed in the first insulating layer.   The wiring board according to claim 2, wherein the first insulating layer has a thickness of 1 μm to 30 μm.   The wiring board according to claim 2, further comprising a board in contact with the second insulating layer.   The wiring board according to claim 1, wherein the bottom portion of the concave portion faces a central portion of a current path of the resistance element. The resistive film is connected between the conductive thin films,
The through hole is formed to expose the conductive thin film,
The bottom portion is the wiring board according to any one of claims 1 to 5, characterized in that opposite to the resistive film of said recess. The conductive thin film is formed on the resistance film,
The bottom of the recess is opposed to the conductive thin film;
The through hole, the wiring substrate according to any one of claims 1 to 5, characterized in that it is formed so as to expose the resistive layer. The wiring board according to claim 1 , wherein a corner formed by a side surface and a bottom surface of the recess is rounded. The conductive thin film of the resistive element contains copper,
The wiring board according to any one of claims 1 to 8, wherein a precursor of at least a portion of the insulating layer that forms the concave portion contains polyamic acid. The heat dissipation wiring layer contains copper,
The wiring board according to any one of claims 1 to 8, wherein a precursor of at least a portion of the insulating layer that forms the concave portion contains polyamic acid. 11. The wiring board according to claim 9, wherein a portion of the insulating layer that forms a bottom portion of the concave portion contains copper. The recess, the wiring board according to any one of claims 1 to 11, characterized in that at least one of the projections or recesses of the bottom part.
Forming a resistance element;
Forming an insulating layer in contact with the resistance element with a photosensitive resin ;
The insulating layer has a through hole that exposes the resistive element, a bottom portion that faces the resistive element, and a concave portion that does not expose the resistive element, and an exposure of a region that forms the through hole and a region that forms the concave portion. Forming the same process by varying the amount ; and
Forming a conductive wiring layer electrically connected to the resistance element in the through hole;
Forming a heat-dissipating wiring layer in the recess. 14. The method of manufacturing a wiring board according to claim 13 , wherein the conductive wiring layer and the heat dissipation wiring layer are formed by the same process. When exposing the precursor layer of the first insulating layer,
The manufacturing method of a wiring board according to claim 13 or 14 , wherein the light transmittance of the first mask covering the region for forming the through hole and the second mask covering the region for forming the recess are different. Method. Forming a conductive thin film which is a part of the resistance element in a region facing the region where the through hole is formed;
Forming a resistive film that is part of the resistive element in a region facing the region where the concave portion is formed, and having a light reflectance different from that of the conductive thin film;
The said through-hole and the said recessed part are formed by forming the precursor layer of the said 1st insulating layer on the said resistive element, and exposing the precursor layer of the said insulating layer, The Claim 13 or 14 characterized by the above-mentioned. Wiring board manufacturing method. The first insulating layer remains between the recess and the resistance element by reacting a part of the resistance element facing the region where the recess is formed and a part of the precursor layer of the first insulating layer. The method of manufacturing a wiring board according to claim 13 , wherein the recess is formed. The precursor of the insulating layer is a photosensitive resin containing polyamic acid,
The method for manufacturing a wiring board according to claim 17 , wherein at least a part of the resistance element contains copper. Forming a heat dissipation wiring layer;
Forming a first insulating layer covering the heat dissipation wiring layer;
Forming a resistance element on the first insulating layer between the heat dissipation wiring layer and the first insulating layer;
Forming a second insulating layer in contact with the resistance element;
Forming a through hole exposing the resistance element in the second insulating layer;
Wherein the through hole, seen including a step of forming a conductive wiring layer connecting said resistive element electrically,
In the step of forming the first insulating layer, the heat insulating wiring layer and a part of the precursor layer of the first insulating layer are reacted to leave the first insulating layer on the heat dissipating wiring layer. And forming the first insulating layer . A method for manufacturing a wiring board, comprising: The precursor of the first insulating layer is a photosensitive resin containing polyamic acid,
The method for manufacturing a wiring board according to claim 19 , wherein the heat dissipation wiring layer contains copper.

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